JP7800366B2 - Current Sensor - Google Patents

Description

This disclosure relates to a current sensor.

As described in Patent Document 1, a current sensor is known that detects the AC current flowing through an inverter used to drive an AC motor in a hybrid or electric vehicle. This current sensor includes a bus bar through which the inverter's AC current flows, a core through which a magnetic field generated by the AC current flowing through the bus bar passes, and a sensor chip placed in a gap formed in the core. The sensor chip detects the magnetic field passing through this core gap, thereby detecting the AC current flowing through the inverter.

JP 2008-51704 A

According to the inventors' research, there is a need to expand the range of current magnitudes that can be detected by current sensors. However, when the current magnitudes detected by current sensors increase, magnetic saturation occurs in the core of current sensors such as those described in Patent Document 1, making it difficult to expand the range of current magnitudes that can be detected by the current sensors.

The present disclosure aims to provide a current sensor that suppresses magnetic saturation.

The invention of claim 1 is a current sensor including a bus bar (100, 200, 300) formed in a plate shape, a core hole (114, 214, 314) into which the bus bar is inserted, a first end face (115, 215, 315) facing a width direction (DW) of the bus bar, a second end face (116, 216, 316) facing the first end face in the width direction, and a gap forming portion including a gap (117, 217, 317) formed by the first end face and the second end face and communicating with the core hole and the outside. a core (110, 120, 130) having a core horizontal portion (112, 212, 312, 1121, 2122, 3123) connected to the gap forming portion and extending in the thickness direction (DT) of the bus bar, and a core bottom portion (113, 213, 313, 1131, 2132, 3133) connected to the core horizontal portion and extending in the width direction and forming a core hole together with the gap forming portion and the core horizontal portion; and a detection unit (120, 220, 320) for detecting the strength of the magnetic field generated in the gap. The core is formed of a grain-oriented electromagnetic steel sheet, so that the magnetic permeability of the lateral core portion is smaller than that of the bottom core portion. The core is laminated, and the gap forming portion, the lateral core portion, and the bottom core portion are integrated. The core has protrusions (1151, 1152, 2151, 2152, 3151, 3152) protruding in the thickness direction from the outer surface of the gap forming portion facing outward in the thickness direction. 52), the protrusion portion includes protrusion surfaces (1161, 1162, 2161, 2162, 3161, 3162), the protrusion surfaces face inward in the width direction and are connected to the first end surfaces, and if a line passing through the center in the thickness direction of the surface where the protrusion surfaces and the first end surfaces are joined and extending in the width direction is taken as a center line (O1, O2, O3), the detection unit is positioned closer to the core hole than the center line, and the length of the bottom of the core in the thickness direction is shorter than the length of the lateral part of the core in the width direction .

This makes the magnetic flux density applied to the side portions of the core lower than the magnetic flux density applied to the bottom portion of the core, thereby suppressing magnetic saturation in the side portions of the core and therefore suppressing magnetic saturation in the core.

Note that the reference symbols in parentheses attached to each component indicate an example of the correspondence between that component and the specific components described in the embodiments described below.

FIG. 2 is a perspective view of the current sensor according to the first embodiment. 2 is a cross-sectional view taken along line II-II in FIG. 1; FIG. 2 is a top view of the bus bar, core, detection unit, lead wire, board, and terminal of the current sensor. FIG. 10 is a diagram showing the relationship between the magnetic field strength, the magnetic flux density applied to the first easy axis portion, and the magnetic flux density applied to the first hard axis portion. FIG. 10 is a cross-sectional view of a current sensor according to a second embodiment. FIG. 10 is a cross-sectional view of a current sensor according to a third embodiment. FIG. 2 is a top view of the bus bar, core, detection unit, lead wire, board, and terminal of the current sensor. FIG. 10 is a cross-sectional view of a current sensor according to a fourth embodiment. FIG. 10 is a cross-sectional view of a current sensor according to a fifth embodiment. FIG. 13 is a cross-sectional view of a current sensor according to a sixth embodiment. FIG. 13 is a cross-sectional view of a current sensor according to a seventh embodiment. FIG. 13 is a cross-sectional view of a current sensor according to an eighth embodiment. FIG. 13 is a cross-sectional view of a current sensor according to a ninth embodiment. FIG. 23 is a cross-sectional view of a current sensor according to a tenth embodiment. FIG. 23 is a cross-sectional view of a current sensor according to an eleventh embodiment. FIG. 23 is a cross-sectional view of a first core and a first detection portion of a current sensor according to a twelfth embodiment. FIG. 4 is a cross-sectional view of a second core and a second detection portion of the current sensor. FIG. 4 is a cross-sectional view of a third core and a third detection portion of the current sensor. FIG. 23 is a cross-sectional view of a first core and a first detection portion of a current sensor according to a thirteenth embodiment. FIG. 4 is a cross-sectional view of a second core and a second detection portion of the current sensor. FIG. 4 is a cross-sectional view of a third core and a third detection portion of the current sensor. FIG. 23 is a cross-sectional view of a first core and a first detection portion of a current sensor according to a fourteenth embodiment. FIG. 4 is a cross-sectional view of a second core and a second detection portion of the current sensor. FIG. 4 is a cross-sectional view of a third core and a third detection portion of the current sensor. FIG. 23 is a cross-sectional view of a first core of a current sensor according to a fifteenth embodiment. FIG. 4 is a cross-sectional view of a second core of the current sensor. FIG. 4 is a cross-sectional view of a third core of the current sensor. FIG. 23 is a cross-sectional view of a first core of a current sensor according to a sixteenth embodiment. FIG. 4 is a cross-sectional view of a second core of the current sensor. FIG. 4 is a cross-sectional view of a third core of the current sensor. FIG. 23 is a cross-sectional view of the first core, the second core, and the third core in the current sensor of the seventeenth embodiment. FIG. 23 is a cross-sectional view of the first core, the second core, and the third core in the current sensor of the eighteenth embodiment. 20 is a cross-sectional view of the first core, the second core, and the third core in the current sensor of the 19th embodiment. FIG. 20 is a cross-sectional view of the first core, the second core, and the third core in the current sensor of the twentieth embodiment. 21. A cross-sectional view of the first plate portion of the first bus bar and the first opening of the case in the current sensor of the 21st embodiment. Cross-sectional view taken along line XXXVI-XXXVI in Figure 35. Cross-sectional view of line XXXVII-XXXVII in Figure 35. 10 is a cross-sectional view of a second plate portion of a second bus bar and a second opening of a case in the current sensor. FIG. Cross-sectional view of line XXXIX-XXXIX in Figure 38. Cross-sectional view of line XL-XL in Figure 38. 10 is a cross-sectional view of a third plate portion of a third bus bar and a third opening of a case in the current sensor. FIG. Cross-sectional view taken along line XLII-XLII in Figure 41. Cross-sectional view taken along line XLIII-XLIII in Figure 41. 22nd embodiment of the current sensor, a first plate portion of the first bus bar and a first opening of the case cross-sectional view. 10 is a cross-sectional view of a second plate portion of a second bus bar and a second opening of a case in the current sensor. FIG. 10 is a cross-sectional view of a third plate portion of a third bus bar and a third opening of a case in the current sensor. FIG. 23rd embodiment of the current sensor of the first plate portion of the first bus bar and the first opening of the case cross-sectional view. 10 is a cross-sectional view of a second plate portion of a second bus bar and a second opening of a case in the current sensor. FIG. 10 is a cross-sectional view of a third plate portion of a third bus bar and a third opening of a case in the current sensor. FIG. 24th embodiment of the current sensor of the first plate portion of the first bus bar and the first opening of the case cross-sectional view. 10 is a cross-sectional view of a second plate portion of a second bus bar and a second opening of a case in the current sensor. FIG. 10 is a cross-sectional view of a third plate portion of a third bus bar and a third opening of a case in the current sensor. FIG. 25th embodiment of the current sensor of the first plate portion of the first bus bar and the first opening of the case cross-sectional view. 10 is a cross-sectional view of a second plate portion of a second bus bar and a second opening of a case in the current sensor. FIG. 10 is a cross-sectional view of a third plate portion of a third bus bar and a third opening of a case in the current sensor. FIG. 26th embodiment of the current sensor of the first bus bar, the first core, the first detection portion, and the case of the cross-sectional view. FIG. 4 is a cross-sectional view of a second bus bar, a second core, a second detection portion, and a case of the current sensor. FIG. 4 is a cross-sectional view of a third bus bar, a third core, a third detection portion, and a case of the current sensor. FIG. 10 is a relationship diagram between the first ratio and the amplitude ratio in the current sensor. 27th embodiment of the current sensor of the first bus bar, the first core, and the first detection portion of the cross-sectional view. FIG. 4 is a cross-sectional view of a second bus bar, a second core, and a second detection portion in the current sensor. FIG. 4 is a cross-sectional view of a third bus bar, a third core, and a third detection portion in the current sensor. 28th embodiment of the current sensor of the first bus bar and the first opening of the case cross-sectional view. Cross-sectional view taken along line LXIV-LXIV in Figure 63. FIG. 6 is a cross-sectional view of a second bus bar and a second opening of the case in the current sensor. Cross-sectional view taken along line LXVI-LXVI in Figure 65. FIG. 10 is a cross-sectional view of a third bus bar and a third opening of the case in the current sensor. Cross-sectional view taken along line LXVIII-LXVIII in Figure 67. 29th embodiment of the current sensor of the first bus bar and the first opening of the case cross-sectional view. FIG. 6 is a cross-sectional view of a second bus bar and a second opening of the case in the current sensor. FIG. 10 is a cross-sectional view of a third bus bar and a third opening of the case in the current sensor. 30. A cross-sectional view of the first bus bar and the first opening of the case in the current sensor of the 30th embodiment. FIG. 6 is a cross-sectional view of a second bus bar and a second opening of the case in the current sensor. FIG. 10 is a cross-sectional view of a third bus bar and a third opening of the case in the current sensor. 31 is a cross-sectional view of a first bus bar and a first opening of a case in a current sensor according to a thirty-first embodiment. FIG. FIG. 6 is a cross-sectional view of a second bus bar and a second opening of the case in the current sensor. FIG. 10 is a cross-sectional view of a third bus bar and a third opening of the case in the current sensor.

Embodiments will be described below with reference to the drawings. Note that, in the following embodiments, identical or equivalent parts will be designated by the same reference numerals, and their description will be omitted.

(First embodiment)
The current sensor 5 of this embodiment is used in an inverter that drives a three-phase AC motor mounted on a vehicle (not shown). Specifically, as shown in Figures 1 to 3, the current sensor 5 includes a first sensor 10, a second sensor 20, a third sensor 30, a circuit board 50, a plurality of terminals 60, and a case 70.

The first sensor 10 has a first bus bar 100, a first core 110, a first detection portion 120, and a first lead wire 130.

The first bus bar 100 is formed into a plate shape from copper or the like. Furthermore, the surface of the first bus bar 100 is plated as needed to prevent surface oxidation. Furthermore, the first bus bar 100 has a first plate portion 101, a first extension portion 102, and a second extension portion 103.

The first plate portion 101 includes a first bolt hole 104. Bolts (not shown) are inserted into the first bolt hole 104 and holes provided in the inverter. This connects the first plate portion 101 to a part of the inverter.

Hereinafter, for convenience, the longitudinal direction DL of the first plate portion 101 will be referred to simply as the longitudinal direction DL. Furthermore, the width direction DW of the first plate portion 101 will be referred to simply as the width direction DW. Furthermore, the thickness direction DT of the first plate portion 101 will be referred to simply as the thickness direction DT.

The first extension portion 102 is connected to the side of the first plate portion 101 opposite the first bolt hole 104. The first extension portion 102 also extends in the thickness direction DT from the boundary between the first extension portion 102 and the first plate portion 101.

The second extension portion 103 is connected to the side of the first extension portion 102 opposite the first plate portion 101. The second extension portion 103 also extends in the longitudinal direction DL from the boundary between the second extension portion 103 and the first extension portion 102. Furthermore, the second extension portion 103 is connected to part of the inverter by being welded to the inverter.

The first core 110 is formed in a C-shape from a soft magnetic material such as permalloy or directional electromagnetic steel sheet. For example, the first core 110 is formed by bending a plate of soft magnetic material into a C-shape. The first core 110 also includes a first gap forming portion 111, a first easy axis portion 112, a first hard axis portion 113, and a first core hole 114.

The first gap forming portion 111 is formed in a plate shape extending in the width direction DW. The first gap forming portion 111 is separated from the first busbar 100 in the thickness direction DT. The first outer lateral corner C1_out_top, which is the outer corner of the first gap forming portion 111 in the width direction DW, is rounded. The first gap forming portion 111 includes a first core end face 115, a second core end face 116, and a first gap 117. When the second core end face 116 is projected in the width direction DW, the first core end face 115 overlaps with the projected second core end face 116. The first gap 117 is a space defined by the first core end face 115 and the second core end face 116. The first gap 117 is connected to the first core hole 114 and the outside of the first core 110.

Here, the surface of the first plate portion 101 facing the first core end face 115 and the second core end face 116 in the thickness direction DT is referred to as the first plate surface S1. When the first core end face 115 is projected onto the first plate surface S1 in the thickness direction DT, the portion of the first plate surface S1 that overlaps with the projected first core end face 115 is referred to as the first projection portion Ps1. When the second core end face 116 is projected onto the first plate surface S1 in the thickness direction DT, the portion of the first plate surface S1 that overlaps with the projected second core end face 116 is referred to as the second projection portion Ps2. Furthermore, the region of the first plate surface S1 defined by the first projection portion Ps1 and the second projection portion Ps2 is referred to as the first region R1. A first recess 118 is formed in at least a portion of the first region R1, recessed in the thickness direction DT. The first recess 118 is formed in a rectangular shape. The first recess 118 is not limited to being rectangular, but may also be polygonal or circular.

The first easy axis portion 112 is connected to the first gap forming portion 111. The first easy axis portion 112 extends in the thickness direction DT from the boundary between the first easy axis portion 112 and the first gap forming portion 111. Furthermore, the first lateral inner corner C1_in_top on the inner side of the boundary between the first easy axis portion 112 and the first gap forming portion 111 is rounded. The first easy axis portion 112 is separated from the first busbar 100 in the width direction DW.

The first hard axis portion 113 is connected to the first easy axis portion 112. The first hard axis portion 113 extends in the width direction DW. The magnetic permeability of the first hard axis portion 113 is smaller than that of the first easy axis portion 112. The saturation magnetic flux density of the first hard axis portion 113 is smaller than that of the first easy axis portion 112. The length of the first hard axis portion 113 in the thickness direction DT is longer than the length of the first easy axis portion 112 in the width direction DW. Note that here, magnetic permeability refers to, for example, the maximum magnetic permeability, which is the maximum value of the change in magnetic flux density with respect to the strength of the magnetic field.

The first core hole 114 is a space formed by the first gap forming portion 111, the first easy axis portion 112, and the first hard axis portion 113. A portion of the first plate portion 101 of the first busbar 100 is inserted into the first core hole 114.

The first detection unit 120 is disposed in the first gap 117. Therefore, when the first core end face 115 is projected in the width direction DW, the first detection unit 120 overlaps with the projected first core end face 115. Furthermore, when the second core end face 116 is projected in the width direction DW, the first detection unit 120 overlaps with the projected second core end face 116. The first detection unit 120 also includes, for example, a Hall element, a TMR element, a GMR element, and an AMR element (not shown). Using these elements, the first detection unit 120 detects the strength of the magnetic field in the width direction DW applied to the first detection unit 120. Furthermore, the first detection unit 120 outputs a signal corresponding to the strength of the detected magnetic field to the outside. The first lead wire 130 is connected to the first detection unit 120. Note that TMR stands for Tunnel Magneto Resistive. GMR stands for Giant Magneto Resistive. AMR stands for Anisotropic Magneto Resistive.

The second sensor 20 has a second bus bar 200, a second core 210, a second detection portion 220, and a second lead wire 230.

The second bus bar 200 is formed into a plate shape from copper or the like. If necessary, the surface of the second bus bar 200 may be plated to prevent surface oxidation. Furthermore, the second bus bar 200 has a second plate portion 201, a third extension portion 202, and a fourth extension portion 203.

The second plate portion 201 includes a second bolt hole 204. Bolts (not shown) are inserted into the second bolt hole 204 and holes provided in the inverter. This connects the second plate portion 201 to a part of the inverter.

The third extension portion 202 is connected to the side of the second plate portion 201 opposite the second bolt hole 204. The third extension portion 202 also extends in the thickness direction DT from the boundary between the third extension portion 202 and the second plate portion 201.

The fourth extension portion 203 is connected to the side of the third extension portion 202 opposite the second plate portion 201. The fourth extension portion 203 also extends in the longitudinal direction DL from the boundary between the fourth extension portion 203 and the third extension portion 202. Furthermore, the fourth extension portion 203 is connected to part of the inverter by being welded to the inverter.

The second core 210 is formed in a C-shape from a soft magnetic material such as permalloy or directional electromagnetic steel plate. For example, the second core 210 is formed by bending a plate of soft magnetic material into a C-shape. The second core 210 also includes a second gap forming portion 211, a second easy axis portion 212, a second hard axis portion 213, and a second core hole 214.

The second gap forming portion 211 is formed in a plate shape extending in the width direction DW. The second gap forming portion 211 is separated from the second bus bar 200 in the thickness direction DT. The second lateral outer corner C2_out_top, which is the outer corner of the second gap forming portion 211 in the width direction DW, is rounded. The second lateral outer corner C2_out_top and the first lateral outer corner C1_out_top face each other in the width direction DW. The second gap forming portion 211 includes a third core end face 215, a fourth core end face 216, and a second gap 217. When the fourth core end face 216 is projected in the width direction DW, the third core end face 215 overlaps with the projected fourth core end face 216. The second gap 217 is a space defined by the third core end face 215 and the fourth core end face 216. Furthermore, the second gap 217 is in communication with the second core hole 214 and the outside of the second core 210.

Here, the surface of the second plate portion 201 that faces the third core end face 215 and the fourth core end face 216 in the thickness direction DT is referred to as the second plate surface S2. When the third core end face 215 is projected onto the second plate surface S2 in the thickness direction DT, the portion of the second plate surface S2 that overlaps with the projected third core end face 215 is referred to as the third projection portion Ps3. When the fourth core end face 216 is projected onto the second plate surface S2 in the thickness direction DT, the portion of the second plate surface S2 that overlaps with the projected fourth core end face 216 is referred to as the fourth projection portion Ps4. Furthermore, the region of the second plate surface S2 defined by the third projection portion Ps3 and the fourth projection portion Ps4 is referred to as the second region R2. A second recess 218 is formed in at least a portion of the second region R2, recessed in the thickness direction DT. The second recess 218 is formed in a rectangular shape. The second recess 218 is not limited to being rectangular in shape, and may also be polygonal or circular.

The second easy axis portion 212 is connected to the second gap forming portion 211. The second easy axis portion 212 extends in the thickness direction DT from the boundary between the second easy axis portion 212 and the second gap forming portion 211. Furthermore, the second lateral inner corner C2_in_top on the inner side at the boundary between the second easy axis portion 212 and the second gap forming portion 211 is rounded. The second easy axis portion 212 is separated from the second bus bar 200 in the width direction DW.

The second hard axis region 213 is connected to the second easy axis region 212. The second hard axis region 213 extends in the width direction DW. The magnetic permeability of the second hard axis region 213 is smaller than that of the second easy axis region 212. The saturation magnetic flux density of the second hard axis region 213 is smaller than that of the second easy axis region 212. The length of the second hard axis region 213 in the thickness direction DT is longer than the length of the second easy axis region 212 in the width direction DW.

The second core hole 214 is a space formed by the second gap forming portion 211, the second easy axis portion 212, and the second hard axis portion 213. A portion of the second plate portion 201 of the second busbar 200 is inserted into the second core hole 214.

The second detection unit 220 is disposed in the second gap 217. Therefore, when the third core end face 215 is projected in the width direction DW, the second detection unit 220 overlaps with the projected third core end face 215. Furthermore, when the fourth core end face 216 is projected in the width direction DW, the second detection unit 220 overlaps with the projected fourth core end face 216. The second detection unit 220 also includes, for example, a Hall element, a TMR element, a GMR element, and an AMR element (not shown). Using these elements, the second detection unit 220 detects the strength of the magnetic field in the width direction DW applied to the second detection unit 220. Furthermore, the second detection unit 220 outputs a signal corresponding to the strength of the detected magnetic field to the outside. The second lead wire 230 is connected to the second detection unit 220.

The third sensor 30 has a third bus bar 300, a third core 310, a third detection portion 320, and a third lead wire 330.

The third bus bar 300 is formed into a plate shape from copper or the like. If necessary, the surface of the third bus bar 300 may be plated to prevent surface oxidation. Furthermore, the third bus bar 300 has a third plate portion 301, a fifth extension portion 302, and a sixth extension portion 303.

The third plate portion 301 includes a third bolt hole 304. Bolts (not shown) are inserted into the third bolt hole 304 and holes provided in the inverter. This connects the third plate portion 301 to a part of the inverter.

The fifth extension portion 302 is connected to the side of the third plate portion 301 opposite the third bolt hole 304. The fifth extension portion 302 also extends in the thickness direction DT from the boundary between the fifth extension portion 302 and the third plate portion 301.

The sixth extension portion 303 is connected to the fifth extension portion 302 on the side opposite to the third plate portion 301. The sixth extension portion 303 also extends in the longitudinal direction DL from the boundary between the sixth extension portion 303 and the fifth extension portion 302. Furthermore, the sixth extension portion 303 is connected to part of the inverter by being welded to the inverter.

The third core 310 is formed in a C-shape from a soft magnetic material such as permalloy or a grain-oriented electromagnetic steel plate. For example, the third core 310 is formed by bending a plate of soft magnetic material into a C-shape. The third core 310 also includes a third gap forming portion 311, a third easy axis portion 312, a third hard axis portion 313, and a third core hole 314.

The third gap forming portion 311 is formed in a plate shape extending in the width direction DW. The third gap forming portion 311 is separated from the third bus bar 300 in the thickness direction DT. The third lateral outer corner C3_out_top, which is the outer corner of the third gap forming portion 311 in the width direction DW, is rounded. The third lateral outer corner C3_out_top and the second lateral outer corner C2_out_top face each other in the width direction DW. The third gap forming portion 311 includes a fifth core end face 315, a sixth core end face 316, and a third gap 317. When the sixth core end face 316 is projected in the width direction DW, the fifth core end face 315 overlaps with the projected sixth core end face 316. The third gap 317 is a space defined by the fifth core end face 315 and the sixth core end face 316. Furthermore, the third gap 317 is in communication with the third core hole 314 and the outside of the third core 310.

Here, the surface of the third plate portion 301 facing the fifth core end face 315 and the sixth core end face 316 in the thickness direction DT is referred to as the third plate surface S3. When the fifth core end face 315 is projected onto the third plate surface S3 in the thickness direction DT, the portion of the third plate surface S3 that overlaps with the projected fifth core end face 315 is referred to as the fifth projection portion Ps5. When the sixth core end face 316 is projected onto the third plate surface S3 in the thickness direction DT, the portion of the third plate surface S3 that overlaps with the projected sixth core end face 316 is referred to as the sixth projection portion Ps6. Furthermore, the region of the third plate surface S3 defined by the fifth projection portion Ps5 and the sixth projection portion Ps6 is referred to as the third region R3. A third recess 318 is formed in at least a portion of the third region R3, recessed in the thickness direction DT. The third recess 318 is formed in a rectangular shape. The third recess 318 is not limited to being rectangular in shape, and may also be polygonal or circular.

The third easy axis portion 312 is connected to the third gap forming portion 311. The third easy axis portion 312 extends in the thickness direction DT from the boundary between the third easy axis portion 312 and the third gap forming portion 311. Furthermore, the third lateral inner corner C3_in_top on the inner side at the boundary between the third easy axis portion 312 and the third gap forming portion 311 is rounded. The third easy axis portion 312 is separated from the third bus bar 300 in the width direction DW.

The third hard axis portion 313 is connected to the third easy axis portion 312. The third hard axis portion 313 extends in the width direction DW. The magnetic permeability of the third hard axis portion 313 is smaller than that of the third easy axis portion 312. The saturation magnetic flux density of the third hard axis portion 313 is smaller than that of the third easy axis portion 312. The length of the third hard axis portion 313 in the thickness direction DT is longer than the length of the third easy axis portion 312 in the width direction DW.

The third core hole 314 is a space formed by the third gap forming portion 311, the third easy axis portion 312, and the third hard axis portion 313. A portion of the third plate portion 301 of the third busbar 300 is inserted into the third core hole 314.

The third detection unit 320 is disposed in the third gap 317. Therefore, when the fifth core end face 315 is projected in the width direction DW, the third detection unit 320 overlaps with the projected fifth core end face 315. Furthermore, when the sixth core end face 316 is projected in the width direction DW, the third detection unit 320 overlaps with the projected sixth core end face 316. The third detection unit 320 also includes, for example, a Hall element, a TMR element, a GMR element, and an AMR element (not shown). Using these elements, the third detection unit 320 detects the strength of the magnetic field in the width direction DW applied to the third detection unit 320. Furthermore, the third detection unit 320 outputs a signal corresponding to the strength of the detected magnetic field to the outside. The third lead wire 330 is connected to the third detection unit 320.

The substrate 50 is a printed circuit board. The substrate 50 is connected to the first lead wire 130, the second lead wire 230, and the third lead wire 330 by soldering or the like.

The terminal 60 is connected to the circuit board 50 by soldering or the like. The terminal 60 is also connected to a computing device (not shown).

The case 70 is made of a thermoplastic resin such as PBT. For example, the case 70 is formed by injection molding. The case 70 also has a storage section 700, a flange section 701, and a fixing collar 702. PBT is an abbreviation for Poly Butylene Terephthalate.

The accommodating section 700 is formed in the shape of a rectangular tube. The accommodating section 700 accommodates the first core 110, the second core 210, the third core 310, the first detection section 120, the second detection section 220, the third detection section 320, the first lead wire 130, the second lead wire 230, and the third lead wire 330. The accommodating section 700 also accommodates the circuit board 50 and a portion of the terminal 60. The space within the accommodating section 700 is filled with a resin such as urethane (not shown). This seals the interior of the accommodating section 700, protecting the components housed within the accommodating section 700. Furthermore, the accommodating portion 700 accommodates the first extension portion 102 and part of the second extension portion 103 of the first bus bar 100, the third extension portion 202 and part of the fourth extension portion 203 of the second bus bar 200, and the fifth extension portion 302 and part of the sixth extension portion 303 of the third bus bar 300. The accommodating portion 700 also includes a first opening 711, a second opening 712, and a third opening 713.

A portion of the first opening 711 is inserted into the first core hole 114. A portion of the first plate portion 101 of the first busbar 100 is inserted into the space of the first opening 711. The first opening 711 also includes a first opposing surface 721 and a first protruding portion 731. The first opposing surface 721 faces the first plate portion 101 in the width direction DW and the thickness direction DT. The first protruding portion 731 protrudes from the first opposing surface 721 in the thickness direction DT and the width direction DW. The first protruding portion 731 also contacts the first plate portion 101. This positions the case 70 and the first busbar 100. A first space 741 is formed between the first opposing surface 721 and the first plate portion 101.

A portion of the second opening 712 is inserted into the second core hole 214. A portion of the second plate portion 201 of the second busbar 200 is inserted into the space of the second opening 712. The second opening 712 also includes a second opposing surface 722 and a second protruding portion 732. The second opposing surface 722 faces the second plate portion 201 in the width direction DW and the thickness direction DT. The second protruding portion 732 protrudes from the second opposing surface 722 in the thickness direction DT and the width direction DW. The second protruding portion 732 also contacts the second plate portion 201. This positions the case 70 and the second busbar 200. A second space 742 is formed between the second opposing surface 722 and the second plate portion 201.

A portion of the third opening 713 is inserted into the third core hole 314. A portion of the third plate portion 301 of the third busbar 300 is inserted into the space of the third opening 713. The third opening 713 also includes a third opposing surface 723 and a third protruding portion 733. The third opposing surface 723 faces the third plate portion 301 in the width direction DW and the thickness direction DT. The third protruding portion 733 protrudes from the third opposing surface 723 in the thickness direction DT and the width direction DW. The third protruding portion 733 also contacts the third plate portion 301. This positions the case 70 and the third busbar 300. A third space 743 is formed between the third opposing surface 723 and the third plate portion 301.

The flange 701 protrudes in the width direction DW from a portion of the housing 700 on the width direction DW side. The flange 701 also includes a flange hole 704. The flange hole 704 is connected to the outside in the thickness direction DT. A fixing collar 702 is inserted into the flange hole 704. An external shaft (not shown) is inserted into the fixing collar 702, connecting the case 70 to the outside and thereby fixing the current sensor 5 to the outside.

The current sensor 5 of the first embodiment is configured as described above. Next, we will explain how the current sensor 5 detects three-phase AC current in the inverter.

The first plate portion 101 of the first busbar 100 in the first sensor 10 is connected to a part of the inverter. Furthermore, the second extension portion 103 of the first busbar 100 is connected to a part of the inverter. Therefore, AC current from the inverter flows through the first plate portion 101. At this time, the AC current flowing through the first plate portion 101 generates a circumferential magnetic field centered on an axis extending in the longitudinal direction DL while passing through the first plate portion 101. Furthermore, this generated magnetic field causes magnetic field lines to pass through the first core 110 and thus through the first gap 117. Therefore, these magnetic field lines pass through the first detection unit 120. Therefore, the first detection unit 120 detects the strength of the magnetic field in the width direction DW. As a result, the first detection unit 120 detects the current from the inverter corresponding to the strength of this magnetic field. The first detection unit 120 also outputs a signal corresponding to the strength of the detected magnetic field to an external computing device (not shown) via the first lead wire 130, the circuit board 50, and the terminal 60. This computing device then calculates the current from the inverter based on the signal from the first detection unit 120.

Here, the magnetic field leaking from the first gap 117 penetrates the first plate portion 101, and changes in the magnetic field over time occur due to changes in the frequency of the inverter's AC current. This generates an induced electromotive force in the opposite direction to the direction of the current flowing from the inverter to the first plate portion 101. The magnetic field generated by the current flowing through the first plate portion 101 due to this induced electromotive force changes the magnetic field applied to the first gap 117. This results in an error in the current detected by the current sensor 5. Furthermore, as the frequency of the inverter's AC current increases, the current flowing on the surface of the first plate portion 101 due to the induced electromotive force increases due to the skin effect, making the magnetic field applied to the first gap 117 more likely to change. This makes it more likely to result in an error in the current detected by the current sensor 5. However, in the first sensor 10, the first recess 118 is formed in the first region R1 of the first plate portion 101, making it easier for the first plate portion 101 to move away from the first gap 117. This prevents magnetic field lines from penetrating the first plate portion 101 from the first gap 117, thereby suppressing the generation of induced electromotive force in the direction opposite to the direction of the current flowing through the first plate portion 101. This reduces the likelihood of errors in the current detected by the current sensor 5, improving the frequency characteristics of the current sensor 5.

In this way, the first sensor 10 detects one phase of the three-phase AC current of the inverter. Similarly to the first sensor 10, the second sensor 20 detects one phase of the three-phase AC current of the inverter. Therefore, in the description of the second sensor 20, the first sensor 10 will be referred to as the second sensor 20. The first busbar 100 will be referred to as the second busbar 200. The first plate portion 101 will be referred to as the second plate portion 201. The second extension portion 103 will be referred to as the fourth extension portion 203. The first core 110 will be referred to as the second core 210. The first gap 117 will be referred to as the second gap 217. The first detection portion 120 will be referred to as the second detection portion 220. The first lead wire 130 will be referred to as the second lead wire 230. The first region R1 will be referred to as the second region R2. The first recess 118 will be referred to as the second recess 218. Similarly to the first sensor 10, the third sensor 30 detects one phase of the three-phase AC current of the inverter. Therefore, in the description of the third sensor 30, the first sensor 10 will be referred to as the third sensor 30. The first busbar 100 will be referred to as the third busbar 300. The first plate portion 101 will be referred to as the third plate portion 301. The second extension portion 103 will be referred to as the sixth extension portion 303. The first core 110 will be referred to as the third core 310. The first gap 117 will be referred to as the third gap 317. The first detection portion 120 will be referred to as the third detection portion 320. The first lead wire 130 will be referred to as the third lead wire 330. The first region R1 will be referred to as the third region R3. The first recess 118 will be referred to as the third recess 318.

As described above, the current sensor 5 detects the three-phase AC current of the inverter. Next, we will explain how the frequency characteristics of the current sensor 5 are improved.

In a comparison current sensor such as that described in Patent Document 1, the magnetic field leaking from the core gap penetrates the bus bar, and changes in the frequency of the AC current cause the magnetic field to change over time, generating an induced electromotive force in the opposite direction to the direction of the current flowing through the bus bar. The magnetic field generated by the current flowing through the bus bar due to this induced electromotive force changes the magnetic field applied to the core gap. This causes an error in the current detected by the comparison current sensor, resulting in a deterioration in the frequency characteristics of the comparison current sensor.

In contrast, the current sensor 5 detects the AC current of the inverter. The current sensor 5 also includes a first bus bar 100, a second bus bar 200, a third bus bar 300, a first core 110, a second core 210, a third core 310, a first detection unit 120, a second detection unit 220, and a third detection unit 320. The first bus bar 100, the second bus bar 200, and the third bus bar 300 are formed in a plate shape. The first core 110 has a first core hole 114 and a first gap forming portion 111. The first bus bar 100 is inserted into the first core hole 114. The first gap forming portion 111 includes a first core end face 115, a second core end face 116, and a first gap 117. The first core end face 115 faces the width direction DW. The second core end face 116 faces the first core end face 115 in the width direction DW. The first gap 117 is formed by the first core end face 115 and the second core end face 116 and communicates with the first core hole 114 and the outside. The second core 210 has a second core hole 214 and a second gap forming portion 211. The second core hole 214 has the second bus bar 200 inserted therein. The second gap forming portion 211 includes a third core end face 215, a fourth core end face 216, and a second gap 217. The third core end face 215 faces the width direction DW. The fourth core end face 216 faces the third core end face 215 in the width direction DW. The second gap 217 is formed by the third core end face 215 and the fourth core end face 216 and communicates with the second core hole 214 and the outside. The third core 310 has a third core hole 314 and a third gap forming portion 311. The third bus bar 300 is inserted into the third core hole 314. The third gap forming portion 311 includes a fifth core end face 315, a sixth core end face 316, and a third gap 317. The fifth core end face 315 faces the width direction DW. The sixth core end face 316 faces the fifth core end face 315 in the width direction DW. The third gap 317 is formed by the fifth core end face 315 and the sixth core end face 316 and communicates with the third core hole 314 and the outside. The first bus bar 100 also has a first projection portion Ps1, a second projection portion Ps2, a first region R1, and a first recess 118. The first projection portion Ps1 is a portion of the first bus bar 100 that overlaps with the projected first core end face 115 when the first core end face 115 is projected onto the first bus bar 100 in the thickness direction DT. The second projection portion Ps2 is a portion of the first bus bar 100 that overlaps with the projected second core end face 116 when the second core end face 116 is projected onto the first bus bar 100 in the thickness direction DT. The first region R1 is a region between the first projection portion Ps1 and the second projection portion Ps2. The first recess 118 is recessed from the first region R1 in the thickness direction DT. Furthermore, the second bus bar 200 has a third projection portion Ps3, a fourth projection portion Ps4, a second region R2, and a second recess 218. The third projection portion Ps3 is a portion of the second bus bar 200 that overlaps with the projected third core end face 215 when the third core end face 215 is projected onto the second bus bar 200 in the thickness direction DT. The fourth projection portion Ps4 is a portion of the second bus bar 200 that overlaps with the projected fourth core end face 216 when the fourth core end face 216 is projected onto the second bus bar 200 in the thickness direction DT. The second region R2 is a region between the third projection portion Ps3 and the fourth projection portion Ps4. The second recess 218 is recessed from the second region R2 in the thickness direction DT. The third bus bar 300 also has a fifth projection portion Ps5, a sixth projection portion Ps6, a third region R3, and a third recess 318. The fifth projection portion Ps5 is a portion of the third bus bar 300 that overlaps with the fifth core end face 315 when the fifth core end face 315 is projected onto the third bus bar 300 in the thickness direction DT. The sixth projection portion Ps6 is a portion of the third bus bar 300 that overlaps with the sixth core end face 316 when the sixth core end face 316 is projected onto the third bus bar 300 in the thickness direction DT. The third region R3 is a region between the fifth projection portion Ps5 and the sixth projection portion Ps6. The third recess 318 is recessed from the third region R3 in the thickness direction DT. The first bus bar 100, the second bus bar 200, and the third bus bar 300 correspond to bus bars. The first core 110, the second core 210, and the third core 310 correspond to cores. The first detection unit 120, the second detection unit 220, and the third detection unit 320 correspond to the detection units. The first core hole 114, the second core hole 214, and the third core hole 314 correspond to the core holes. The first gap forming unit 111, the second gap forming unit 211, and the third gap forming unit 311 correspond to the gap forming units. The first core end face 115, the third core end face 215, and the fifth core end face 315 correspond to the first end face. The second core end face 116, the fourth core end face 216, and the sixth core end face 316 correspond to the second end face. The first gap 117, the second gap 217, and the third gap 317 correspond to the gap. The third projection unit Ps3 and the fifth projection unit Ps5 correspond to the first projection unit Ps1. The fourth projection unit Ps4 and the sixth projection unit Ps6 correspond to the second projection unit Ps2. The first region R1, the second region R2, and the third region R3 correspond to regions. The first recess 118, the second recess 218, and the third recess 318 correspond to recesses.

The first recess 118 makes it easier for the first plate portion 101 to separate from the first gap 117. This prevents magnetic field lines from penetrating from the first gap 117 into the first plate portion 101. The second recess 218 also makes it easier for the second plate portion 201 to separate from the second gap 217. This prevents magnetic field lines from penetrating from the second gap 217 into the second plate portion 201. The third recess 318 also makes it easier for the third plate portion 301 to separate from the third gap 317. This prevents magnetic field lines from penetrating from the third gap 317 into the third plate portion 301. This prevents the generation of induced electromotive force in the direction opposite to the direction of the current flowing through the first plate portion 101, the second plate portion 201, and the third plate portion 301. This reduces the likelihood of errors in the current detected by the current sensor 5, improving the frequency characteristics of the current sensor 5.

The current sensor 5 also provides the following advantages:

[1-1] As described above, the magnetic permeability of the first hard axis portion 113 is smaller than that of the first easy axis portion 112, and therefore the magnetic permeability of the first easy axis portion 112 is greater than that of the first hard axis portion 113. As a result, as shown in FIG. 4 , the linear region of the magnetic flux density of the first easy axis portion 112 relative to the magnetic field strength is greater than the linear region of the magnetic flux density of the first hard axis portion 113 relative to the magnetic field strength. Therefore, magnetic saturation of the first easy axis portion 112 is suppressed, and the lengths of the first easy axis portion 112 in the width direction DW and the longitudinal direction DL can be reduced. Furthermore, the magnetic permeability of the second easy axis portion 212 is greater than that of the second hard axis portion 213. As a result, magnetic saturation of the second easy axis portion 212 is suppressed, and the lengths of the second easy axis portion 212 in the width direction DW and the longitudinal direction DL can be reduced. Furthermore, the magnetic permeability of the third easy axis portion 312 is greater than that of the third hard axis portion 313. This suppresses magnetic saturation in the third easy axis portion 312, allowing the lengths of the third easy axis portion 312 in the width direction DW and the longitudinal direction DL to be reduced. This allows the size of the current sensor 5 to be reduced. In FIG. 4 , Be1 indicates the magnetic flux density of the first easy axis portion 112 versus the magnetic field strength. Bd1 indicates the magnetic flux density of the first hard axis portion 113 versus the magnetic field strength. The first easy axis portion 112, the second easy axis portion 212, and the third easy axis portion 312 correspond to the core side portions. The first hard axis portion 113, the second hard axis portion 213, and the third hard axis portion 313 correspond to the core bottom portion.

In addition, because magnetic saturation of the first easy axis portion 112, the second easy axis portion 212, and the third easy axis portion 312 is suppressed, the range of magnetic strength detected by the current sensor 5 for the current from the inverter is increased. This increases the range of current magnitude detected by the current sensor 5.

[1-2] The saturation magnetic flux density of the first easy axis portion 112 is greater than the saturation magnetic flux density of the first hard axis portion 113. As a result, the linear region of the magnetic flux density of the first easy axis portion 112 relative to the magnetic field strength is greater than the linear region of the magnetic flux density of the first hard axis portion 113 relative to the magnetic field strength. Therefore, magnetic saturation of the first easy axis portion 112 is suppressed, and the lengths of the first easy axis portion 112 in the width direction DW and the longitudinal direction DL can be reduced. Furthermore, the saturation magnetic flux density of the second easy axis portion 212 is greater than the saturation magnetic flux density of the second hard axis portion 213. As a result, magnetic saturation of the second easy axis portion 212 is suppressed, and the lengths of the second easy axis portion 212 in the width direction DW and the longitudinal direction DL can be reduced. Furthermore, the saturation magnetic flux density of the third easy axis portion 312 is greater than the saturation magnetic flux density of the third hard axis portion 313. As a result, magnetic saturation of the third easy axis portion 312 is suppressed, and the lengths of the third easy axis portion 312 in the width direction DW and longitudinal direction DL can be reduced. This allows the size of the current sensor 5 to be reduced.

In addition, because magnetic saturation of the first easy axis portion 112, the second easy axis portion 212, and the third easy axis portion 312 is suppressed, the range of magnetic strength detected by the current sensor 5 for the current from the inverter is increased. This increases the range of current magnitude detected by the current sensor 5.

[1-3] The length in the thickness direction DT of the first hard axis region 113 is equal to or greater than the length in the width direction DW of the first easy axis region 112. As a result, the magnetic flux density applied to the first hard axis region 113 is lower than the magnetic flux density applied to the first easy axis region 112. This suppresses magnetic saturation of the first hard axis region 113. Furthermore, the length in the thickness direction DT of the second hard axis region 213 is equal to or greater than the length in the width direction DW of the second easy axis region 212. This suppresses magnetic saturation of the second hard axis region 213. Furthermore, the length in the thickness direction DT of the third hard axis region 313 is equal to or greater than the length in the width direction DW of the third easy axis region 312. This suppresses magnetic saturation of the third hard axis region 313. This suppresses magnetic saturation in the third hard axis portion 313.

In addition, because magnetic saturation of the first hard axis section 113, the second hard axis section 213, and the third hard axis section 313 is suppressed, the range of magnetic strength detected by the current sensor 5 for the current from the inverter is increased. This increases the range of current magnitude detected by the current sensor 5.

[1-4] The current sensor 5 further includes a case 70. The case 70 houses the second core 210, the second core 210, and the third core 310. The case 70 further includes a first opening 711, a second opening 712, and a third opening 713. The first opening 711 is inserted into the first core hole 114, and the first bus bar 100 is inserted therein. The first opening 711 also includes a first opposing surface 721 and a first protruding portion 731. The first opposing surface 721 faces the first plate portion 101. The first protruding portion 731 protrudes from the first opposing surface 721 toward the first bus bar 100, thereby making contact with the first bus bar 100. A first space 741 is formed between the first opposing surface 721 and the first bus bar 100. The second opening 712 is inserted into the second core hole 214 and the second bus bar 200. The second opening 712 also includes a second opposing surface 722 and a second protruding portion 732. The second opposing surface 722 faces the second plate portion 201. The second protruding portion 732 protrudes from the second opposing surface 722 toward the second bus bar 200 and is in contact with the second bus bar 200. A second space 742 is formed between the second opposing surface 722 and the second plate portion 201. The third opening 713 is inserted into the third core hole 314 and the third bus bar 300 is inserted therein. The third opening 713 also includes a third opposing surface 723 and a third protruding portion 733. The third opposing surface 723 faces the third plate portion 301. The third protrusion 733 protrudes from the third opposing surface 723 toward the third bus bar 300 and is in contact with the third bus bar 300. Furthermore, a third space 743 is formed between the third opposing surface 723 and the third bus bar 300. The first opening 711, the second opening 712, and the third opening 713 correspond to openings. The first opposing surface 721, the second opposing surface 722, and the third opposing surface 723 correspond to opposing surfaces. The first protrusion 731, the second protrusion 732, and the third protrusion 733 correspond to protrusions.

Here, when current flows through the first busbar 100, the second busbar 200, and the third busbar 300, the first busbar 100, the second busbar 200, and the third busbar 300 generate heat. However, in the current sensor 5, the first protrusion 731, the second protrusion 732, and the third protrusion 733 form the first space 741, the second space 742, and the third space 743. This makes it difficult for heat generated by the first busbar 100, the second busbar 200, and the third busbar 300 to be transferred to the case 70. As a result, heat is hardly transferred from the case 70 to the first detection unit 120, the second detection unit 220, and the third detection unit 320. This prevents characteristic changes and failures in the elements of the first detection unit 120, the second detection unit 220, and the third detection unit 320.

Furthermore, the first protrusion 731 contacts the first plate portion 101, thereby positioning the case 70 and the first bus bar 100. This reduces positional variation between the case 70 and the first bus bar 100. Furthermore, the second protrusion 732 contacts the second plate portion 201, thereby positioning the case 70 and the second bus bar 200. This reduces positional variation between the case 70 and the second bus bar 200. Furthermore, the third protrusion 733 contacts the third plate portion 301, thereby positioning the case 70 and the third bus bar 300. This reduces positional variation between the case 70 and the third bus bar 300.

Second Embodiment
5, the second embodiment differs from the first embodiment in the shapes of the first plate portion 101, the second plate portion 201, and the third plate portion 301. Other than this, the second embodiment is similar to the first embodiment.

The first plate portion 101 includes a first through hole 119 instead of the first recess 118. The first through hole 119 penetrates in the thickness direction DT from at least a portion of the first region R1. The second plate portion 201 includes a second through hole 219 instead of the second recess 218. The second through hole 219 penetrates in the thickness direction DT from at least a portion of the second region R2. The third plate portion 301 includes a third through hole 319 instead of the third recess 318. The third through hole 319 penetrates in the thickness direction DT from at least a portion of the third region R3. The first through hole 119, second through hole 219, and third through hole 319 are formed in a rectangular shape. The first through hole 119, second through hole 219, and third through hole 319 correspond to through holes. Furthermore, the first through hole 119, the second through hole 219, and the third through hole 319 are not limited to being formed in a rectangular shape, and may also be formed in a polygonal or circular shape.

The current sensor 5 of the second embodiment is configured as described above. This second embodiment also achieves the same effects as the first embodiment.

(Third embodiment)
6 and 7, the third embodiment differs from the first embodiment in the shapes of the first gap forming portion 111, the second gap forming portion 211, and the third gap forming portion 311. Other than this, the third embodiment is similar to the first embodiment.

The first gap forming portion 111 includes a first inclined surface 151 and a second inclined surface 152 in addition to a first core end surface 115, a second core end surface 116, and a first gap 117.

The first inclined surface 151 is connected to the edge of the first core end face 115. The first inclined surface 151 also extends from the edge of the first core end face 115 in a direction intersecting with the first core end face 115. As a result, the first inclined surface 151 is inclined relative to the first core end face 115 in a direction away from the first gap 117.

The second inclined surface 152 is connected to the edge of the second core end face 116. Furthermore, the second inclined surface 152 extends from the edge of the second core end face 116 in a direction intersecting with the second core end face 116. Therefore, the second inclined surface 152 is inclined relative to the second core end face 116 in a direction away from the second gap 217.

The second gap forming portion 211 includes a third inclined surface 251 and a fourth inclined surface 252 in addition to a third core end surface 215, a fourth core end surface 216, and a second gap 217.

The third inclined surface 251 is connected to the edge of the third core end face 215. The third inclined surface 251 also extends from the edge of the third core end face 215 in a direction intersecting with the third core end face 215. As a result, the third inclined surface 251 is inclined relative to the third core end face 215 in a direction away from the second gap 217.

The fourth inclined surface 252 is connected to the edge of the fourth core end face 216. Furthermore, the fourth inclined surface 252 extends from the edge of the fourth core end face 216 in a direction intersecting with the fourth core end face 216. Therefore, the fourth inclined surface 252 is inclined relative to the fourth core end face 216 in a direction away from the second gap 217.

The third gap forming portion 311 includes a fifth inclined surface 351 and a sixth inclined surface 352 in addition to a fifth core end surface 315, a sixth core end surface 316, and a third gap 317.

The fifth inclined surface 351 is connected to the edge of the fifth core end face 315. The fifth inclined surface 351 also extends from the edge of the fifth core end face 315 in a direction intersecting with the fifth core end face 315. As a result, the fifth inclined surface 351 is inclined relative to the fifth core end face 315 in a direction away from the third gap 317.

The sixth inclined surface 352 is connected to the edge of the sixth core end face 316. Furthermore, the sixth inclined surface 352 extends from the edge of the sixth core end face 316 in a direction intersecting with the sixth core end face 316. Therefore, the sixth inclined surface 352 is inclined relative to the sixth core end face 316 in a direction away from the third gap 317.

The current sensor 5 of the third embodiment is configured as described above. This third embodiment also provides the same advantages as the first embodiment. The third embodiment also provides the following advantages.

[2] Here, if the first inclined surface 151 and the second inclined surface 152 were not present, excess magnetic field lines would pass through the first gap 117 from the corners of the first gap forming portion 111. However, in the third embodiment, the first inclined surface 151 and the second inclined surface 152 make it easier for the corners of the first gap forming portion 111 to move away from the first gap 117. As a result, the number of excess magnetic field lines passing through the first gap 117 from the corners of the first gap forming portion 111 is reduced compared to when the first inclined surface 151 and the second inclined surface 152 are not present. This suppresses magnetic saturation of the first gap forming portion 111. Furthermore, the third inclined surface 251 and the fourth inclined surface 252 make it easier for the corners of the second gap forming portion 211 to move away from the second gap 217. As a result, the number of excess magnetic field lines passing through the second gap 217 from the corners of the second gap forming portion 211 is reduced compared to when the third inclined surface 251 and the fourth inclined surface 252 are not present. This suppresses magnetic saturation of the second gap forming portion 211. Furthermore, the fifth inclined surface 351 and the sixth inclined surface 352 make it easier for the corners of the third gap forming portion 311 to move away from the third gap 317. Therefore, compared to a case where the fifth inclined surface 351 and the sixth inclined surface 352 are not present, the number of excess magnetic field lines passing from the corners of the third gap forming portion 311 to the third gap 317 is reduced. This suppresses magnetic saturation of the third gap forming portion 311. Therefore, since magnetic saturation of the first gap forming portion 111, the second gap forming portion 211, and the third gap forming portion 311 is suppressed, the range of magnetic strength detected by the current sensor 5 for the current from the inverter is widened. Therefore, the range of current magnitude detected by the current sensor 5 is widened. Note that the first inclined surface 151, the third inclined surface 251, and the fifth inclined surface 351 correspond to a first surface that is connected to the edge of the first end surface and extends from the edge of the first end surface in a direction away from the gap. Second inclined surface 152, fourth inclined surface 252, and sixth inclined surface 352 correspond to a second surface that is connected to the edge of the second end surface and extends from the edge of the second end surface away from the gap. The angle between first inclined surface 151 and first core end surface 115 may be 90 degrees. The angle between second inclined surface 152 and second core end surface 116 may be 90 degrees. The angle between third inclined surface 251 and third core end surface 215 may be 90 degrees. The angle between fourth inclined surface 252 and fourth core end surface 216 may be 90 degrees. The angle between fifth inclined surface 351 and fifth core end surface 315 may be 90 degrees. The angle between sixth inclined surface 352 and sixth core end surface 316 may be 90 degrees.

(Fourth embodiment)
8, the fourth embodiment differs from the first embodiment in the shapes of the first core 110, the second core 210, and the third core 310. Other than this, the fourth embodiment is similar to the first embodiment.

The first core 110 includes a first core side portion 1121 and a first core bottom portion 1131 instead of the first easy axis portion 112 and the first hard axis portion 113.

The first core horizontal portion 1121 is connected to the first gap forming portion 111. The first core horizontal portion 1121 extends in the thickness direction DT from the boundary between the first core horizontal portion 1121 and the first gap forming portion 111. Furthermore, the first lateral inner corner C1_in_top on the inside of the boundary between the first core horizontal portion 1121 and the first gap forming portion 111 is rounded. The first core horizontal portion 1121 is separated from the first busbar 100 in the width direction DW.

The first core bottom 1131 is connected to the first core horizontal portion 1121. Furthermore, the first core bottom 1131 extends in the width direction DW. The magnetic permeability of the first core bottom 1131 is greater than that of the first core horizontal portion 1121. The saturation magnetic flux density of the first core bottom 1131 is greater than that of the first core horizontal portion 1121. The length of the first core bottom 1131 in the thickness direction DT is shorter than the length of the first core horizontal portion 1121 in the width direction DW. The first core hole 114 is a space formed by the first gap forming portion 111, the first core horizontal portion 1121, and the first core bottom 1131.

The second core 210 includes a second core side portion 2122 and a second core bottom portion 2132 instead of the second easy axis portion 212 and the second hard axis portion 213.

The second core horizontal portion 2122 is connected to the second gap forming portion 211. The second core horizontal portion 2122 extends in the thickness direction DT. Furthermore, the second lateral inner corner C2_in_top on the inner side at the boundary between the second core horizontal portion 2122 and the second gap forming portion 211 is rounded. The second core horizontal portion 2122 is separated from the second bus bar 200 in the width direction DW.

The second core bottom 2132 is connected to the second core horizontal portion 2122. Furthermore, the second core bottom 2132 extends in the width direction DW. The magnetic permeability of the second core bottom 2132 is greater than that of the second core horizontal portion 2122. The saturation magnetic flux density of the second core bottom 2132 is greater than that of the second core horizontal portion 2122. The length of the second core bottom 2132 in the thickness direction DT is shorter than the length of the second core horizontal portion 2122 in the width direction DW. The second core hole 214 is a space formed by the second gap forming portion 211, the second core horizontal portion 2122, and the second core bottom 2132.

The third core 310 includes a third core side portion 3123 and a third core bottom portion 3133 instead of the third easy axis portion 312 and the third hard axis portion 313.

The third core horizontal portion 3123 is connected to the third gap forming portion 311. The third core horizontal portion 3123 extends in the thickness direction DT from the boundary between the third core horizontal portion 3123 and the third gap forming portion 311. Furthermore, the third lateral inner corner C3_in_top on the inner side at the boundary between the third core horizontal portion 3123 and the third gap forming portion 311 is rounded. The third core horizontal portion 3123 is separated from the third bus bar 300 in the width direction DW.

The third core bottom 3133 is connected to the third core horizontal portion 3123. Furthermore, the third core bottom 3133 extends in the width direction DW. The magnetic permeability of the third core bottom 3133 is greater than that of the third core horizontal portion 3123. The saturation magnetic flux density of the third core bottom 3133 is greater than that of the third core horizontal portion 3123. The length of the third core bottom 3133 in the thickness direction DT is shorter than the length of the third core horizontal portion 3123 in the width direction DW. The third core hole 314 is a space formed by the third gap forming portion 311, the third core horizontal portion 3123, and the third core bottom 3133.

The current sensor 5 of the fourth embodiment is configured as described above. This fourth embodiment also provides the same advantages as the first embodiment. The fourth embodiment also provides the following advantages.

[3] The length of the first core bottom portion 1131 in the thickness direction DT is shorter than the length of the first core horizontal portion 1121 in the width direction DW. As a result, the magnetic flux density applied to the first core horizontal portion 1121 is lower than the magnetic flux density applied to the first core bottom portion 1131. This suppresses magnetic saturation of the first core horizontal portion 1121. Furthermore, the length of the second core bottom portion 2132 in the thickness direction DT is shorter than the length of the second core horizontal portion 2122 in the width direction DW. As a result, the magnetic flux density applied to the second core horizontal portion 2122 is lower than the magnetic flux density applied to the second core bottom portion 2132. This suppresses magnetic saturation of the second core horizontal portion 2122. Furthermore, the length of the third core bottom portion 3133 in the thickness direction DT is shorter than the length of the third core horizontal portion 3123 in the width direction DW. As a result, the magnetic flux density applied to the third core horizontal portion 3123 is lower than the magnetic flux density applied to the third core bottom portion 3133. This prevents magnetic saturation of the third core horizontal portion 3123.

Furthermore, the magnetic permeability of the first core horizontal portion 1121 is smaller than that of the first core bottom portion 1131. As a result, the linear region of the magnetic flux density of the first core bottom portion 1131 versus magnetic field strength is larger than the linear region of the magnetic flux density of the first core horizontal portion 1121 versus magnetic field strength. Therefore, magnetic saturation of the first core bottom portion 1131 is suppressed, and the length of the first core bottom portion 1131 in the thickness direction DT and longitudinal direction DL can be reduced. Furthermore, the magnetic permeability of the second core horizontal portion 2122 is smaller than that of the second core bottom portion 2132. As a result, the linear region of the magnetic flux density of the second core bottom portion 2132 versus magnetic field strength is larger than the linear region of the magnetic flux density of the second core horizontal portion 2122 versus magnetic field strength. As a result, magnetic saturation of the second core bottom portion 2132 is suppressed, allowing the lengths of the second core bottom portion 2132 in the thickness direction DT and longitudinal direction DL to be reduced. Furthermore, the magnetic permeability of the third core horizontal portion 3123 is smaller than that of the third core bottom portion 3133. As a result, the linear region of magnetic flux density in the third core bottom portion 3133 versus magnetic field strength is larger than the linear region of magnetic flux density in the third core horizontal portion 3123 versus magnetic field strength. As a result, magnetic saturation of the third core bottom portion 3133 is suppressed, allowing the lengths of the third core bottom portion 3133 in the thickness direction DT and longitudinal direction DL to be reduced.

Fifth Embodiment
9, the fifth embodiment differs from the fourth embodiment in the shapes of the first core side portion 1121, the first core bottom portion 1131, the second core side portion 2122, the second core bottom portion 2132, the third core side portion 3123, and the third core bottom portion 3133. Other than these, the fifth embodiment is the same as the fourth embodiment.

In the fifth embodiment, the length of the first core bottom portion 1131 in the thickness direction DT is the same as the length of the first core horizontal portion 1121 in the width direction DW. Furthermore, the magnetic permeability of the first core horizontal portion 1121 is different from the magnetic permeability of the first core bottom portion 1131. For example, the magnetic permeability of the first core horizontal portion 1121 is greater than that of the first core bottom portion 1131. Note that "same" here includes the range of manufacturing error. Furthermore, the magnetic permeability of the first core horizontal portion 1121 may be smaller than that of the first core bottom portion 1131.

The length of the second core bottom portion 2132 in the thickness direction DT is the same as the length of the second core horizontal portion 2122 in the width direction DW. Furthermore, the magnetic permeability of the second core horizontal portion 2122 is different from the magnetic permeability of the second core bottom portion 2132. For example, the magnetic permeability of the second core horizontal portion 2122 is greater than the magnetic permeability of the second core bottom portion 2132. Note that the magnetic permeability of the second core horizontal portion 2122 may be smaller than the magnetic permeability of the second core bottom portion 2132.

The length of the third core bottom portion 3133 in the thickness direction DT is the same as the length of the third core horizontal portion 3123 in the width direction DW. Furthermore, the magnetic permeability of the third core horizontal portion 3123 is different from the magnetic permeability of the third core bottom portion 3133. For example, the magnetic permeability of the third core horizontal portion 3123 is greater than the magnetic permeability of the third core bottom portion 3133. Note that the magnetic permeability of the third core horizontal portion 3123 may be smaller than the magnetic permeability of the third core bottom portion 3133.

The current sensor 5 of the fifth embodiment is configured as described above. This fifth embodiment also provides the same advantages as the fourth embodiment. The fifth embodiment also provides the following advantages.

[4] Because the magnetic permeability of the first core horizontal portion 1121 is different from that of the first core bottom portion 1131, the magnetic permeability of either the first core horizontal portion 1121 or the first core bottom portion 1131 is large. This allows the linear region of magnetic flux density versus magnetic field strength to be enlarged in either the first core horizontal portion 1121 or the first core bottom portion 1131. This suppresses magnetic saturation in either the first core horizontal portion 1121 or the first core bottom portion 1131. As a result, either the first core horizontal portion 1121 or the first core bottom portion 1131 can be made smaller. Furthermore, because the magnetic permeability of the second core horizontal portion 2122 is different from that of the second core bottom portion 2132, the magnetic permeability of either the second core horizontal portion 2122 or the second core bottom portion 2132 can be made larger. This makes it possible to widen the linear region of magnetic flux density versus magnetic field strength in either the second core horizontal portion 2122 or the second core bottom portion 2132. Therefore, magnetic saturation in either the second core horizontal portion 2122 or the second core bottom portion 2132 is suppressed. Accordingly, the size of either the second core horizontal portion 2122 or the second core bottom portion 2132 can be reduced. Furthermore, since the permeability of the third core horizontal portion 3123 is different from the permeability of the third core bottom portion 3133, the permeability of either the third core horizontal portion 3123 or the third core bottom portion 3133 can be increased. This makes it possible to widen the linear region of magnetic flux density versus magnetic field strength in either the third core horizontal portion 3123 or the third core bottom portion 3133. Therefore, magnetic saturation in either the third core horizontal portion 3123 or the third core bottom portion 3133 is suppressed. As a result, either the third core side portion 3123 or the third core bottom portion 3133 can be made smaller.

Sixth Embodiment
10, the sixth embodiment differs from the first embodiment in the shapes of the first core 110, the second core 210, and the third core 310. Other than this, the sixth embodiment is similar to the first embodiment.

The first core 110 includes a first core side portion 1121 and a first core bottom portion 1131 instead of the first easy axis portion 112 and the first hard axis portion 113.

The first core horizontal portion 1121 is connected to the first gap forming portion 111. The first core horizontal portion 1121 extends in the thickness direction DT from the boundary between the first core horizontal portion 1121 and the first gap forming portion 111. Furthermore, the first lateral inner corner C1_in_top on the inside of the boundary between the first core horizontal portion 1121 and the first gap forming portion 111 is rounded. The first core horizontal portion 1121 is separated from the first bus bar 100 in the width direction DW. As described above, the first gap forming portion 111 is separated from the first bus bar 100 in the thickness direction DT.

The first core bottom 1131 is connected to the first core horizontal portion 1121. Furthermore, the first core bottom 1131 extends in the width direction DW. The magnetic permeability of the first core bottom 1131 is smaller than that of the first core horizontal portion 1121. The saturation magnetic flux density of the first core bottom 1131 is smaller than that of the first core horizontal portion 1121. The length of the first core bottom 1131 in the thickness direction DT is longer than the length of the first core horizontal portion 1121 in the width direction DW. As described above, the first core hole 114 is a space formed by the first gap forming portion 111, the first core horizontal portion 1121, and the first core bottom 1131.

The second core 210 includes a second core side portion 2122 and a second core bottom portion 2132 instead of the second easy axis portion 212 and the second hard axis portion 213.

The second core horizontal portion 2122 is connected to the second gap forming portion 211. The second core horizontal portion 2122 extends in the thickness direction DT from the boundary between the second core horizontal portion 2122 and the second gap forming portion 211. Furthermore, the second lateral inner corner C2_in_top on the inner side at the boundary between the second core horizontal portion 2122 and the second gap forming portion 211 is rounded. The second core horizontal portion 2122 is spaced apart from the second bus bar 200 in the width direction DW. As described above, the second gap forming portion 211 is spaced apart from the second bus bar 200 in the thickness direction DT.

The second core bottom 2132 is connected to the second core horizontal portion 2122. Furthermore, the second core bottom 2132 extends in the width direction DW. The magnetic permeability of the second core bottom 2132 is smaller than that of the second core horizontal portion 2122. The saturation magnetic flux density of the second core bottom 2132 is smaller than that of the second core horizontal portion 2122. The length of the second core bottom 2132 in the thickness direction DT is longer than the length of the second core horizontal portion 2122 in the width direction DW. As described above, the second core hole 214 is a space formed by the second gap forming portion 211, the second core horizontal portion 2122, and the second core bottom 2132.

The third core 310 includes a third core side portion 3123 and a third core bottom portion 3133 instead of the third easy axis portion 312 and the third hard axis portion 313.

The third core horizontal portion 3123 is connected to the third gap forming portion 311. The third core horizontal portion 3123 extends in the thickness direction DT from the boundary between the third core horizontal portion 3123 and the third gap forming portion 311. Furthermore, the third lateral inner corner C3_in_top on the inner side at the boundary between the third core horizontal portion 3123 and the third gap forming portion 311 is rounded. The third core horizontal portion 3123 is separated from the third bus bar 300 in the width direction DW. As described above, the third gap forming portion 311 is separated from the third bus bar 300 in the thickness direction DT.

The third core bottom 3133 is connected to the third core horizontal portion 3123. Furthermore, the third core bottom 3133 extends in the width direction DW. The magnetic permeability of the third core bottom 3133 is smaller than that of the third core horizontal portion 3123. The saturation magnetic flux density of the third core bottom 3133 is smaller than that of the third core horizontal portion 3123. The length of the third core bottom 3133 in the thickness direction DT is longer than the length of the third core horizontal portion 3123 in the width direction DW. As described above, the third core hole 314 is a space formed by the third gap forming portion 311, the third core horizontal portion 3123, and the third core bottom 3133.

The current sensor 5 of the sixth embodiment is configured as described above. This sixth embodiment also provides the same advantages as the first embodiment. The sixth embodiment also provides the following advantages.

[5-1] The first lateral inner corner C1_in_top, the second lateral inner corner C2_in_top, and the third lateral inner corner C3_in_top are rounded. This shortens the magnetic path length inside each of the first core 110, the second core 210, and the third core 310, thereby increasing the strength of the demagnetizing field inside each of the first core 110, the second core 210, and the third core 310. This reduces the magnetic flux density of each of the first core 110, the second core 210, and the third core 310. This therefore reduces magnetic saturation in each of the first core 110, the second core 210, and the third core 310.

[5-2] The first gap forming portion 111 is spaced apart from the first bus bar 100 in the thickness direction DT, and the first core horizontal portion 1121 is spaced apart from the first bus bar 100 in the width direction DW. This prevents contact between the first bus bar 100 and the first core 110. Furthermore, the second gap forming portion 211 is spaced apart from the second bus bar 200 in the thickness direction DT, and the second core horizontal portion 2122 is spaced apart from the second bus bar 200 in the width direction DW. This prevents contact between the second bus bar 200 and the second core 210. Furthermore, the third gap forming portion 311 is spaced apart from the third bus bar 300 in the thickness direction DT, and the third core horizontal portion 3123 is spaced apart from the third bus bar 300 in the width direction DW. This prevents contact between the third bus bar 300 and the third core 310.

Seventh Embodiment
11, the seventh embodiment differs from the first embodiment in the shapes of the first core 110, the second core 210, and the third core 310. Other than this, the seventh embodiment is the same as the sixth embodiment.

In addition to the first lateral inner corner C1_in_top, the first core 110 has a first bottom inner corner C1_in_btm. The first bottom inner corner C1_in_btm is an inner corner at the boundary between the first core lateral portion 1121 and the first core bottom portion 1131, and is formed in an R-shape. Furthermore, the first core bottom portion 1131 is separated from the first busbar 100 in the thickness direction DT.

In addition to the second lateral inner corner C2_in_top, the second core 210 has a second bottom inner corner C2_in_btm. The second bottom inner corner C2_in_btm is an inner corner at the boundary between the second core lateral portion 2122 and the second core bottom portion 2132, and is formed in an R-shape. Furthermore, the second core bottom portion 2132 is separated from the second bus bar 200 in the thickness direction DT.

The third core 310 has a third bottom inner corner C3_in_btm in addition to a third lateral inner corner C3_in_top. The third bottom inner corner C3_in_btm is an inner corner at the boundary between the third core lateral portion 3123 and the third core bottom portion 3133, and is formed in an R-shape. Furthermore, the third core bottom portion 3133 is separated from the third bus bar 300 in the thickness direction DT.

The current sensor 5 of the seventh embodiment is configured as described above. This seventh embodiment also provides the same advantages as the sixth embodiment. The seventh embodiment also provides the following advantages.

[6-1] The first bottom inner corner C1_in_btm, the second bottom inner corner C2_in_btm, and the third bottom inner corner C3_in_btm are rounded. This shortens the magnetic path length inside each of the first core 110, the second core 210, and the third core 310, thereby increasing the strength of the demagnetizing field inside each of the first core 110, the second core 210, and the third core 310. This reduces the magnetic flux density of each of the first core 110, the second core 210, and the third core 310. This reduces magnetic saturation in each of the first core 110, the second core 210, and the third core 310.

[6-2] The first core bottom 1131 is spaced apart from the first bus bar 100 in the thickness direction DT. This prevents contact between the first bus bar 100 and the first core bottom 1131. Furthermore, the second core bottom 2132 is spaced apart from the second bus bar 200 in the thickness direction DT. This prevents contact between the second bus bar 200 and the second core bottom 2132. Furthermore, the third core bottom 3133 is spaced apart from the third bus bar 300 in the thickness direction DT. This prevents contact between the third bus bar 300 and the third core bottom 3133.

Eighth Embodiment
In the eighth embodiment, as shown in Fig. 12, the shapes of the first lateral inner corner C1_in_top and the first bottom inner corner C1_in_btm are different from those of the seventh embodiment. The shapes of the second lateral inner corner C2_in_top and the second bottom inner corner C2_in_btm are also different from those of the seventh embodiment. Furthermore, the shapes of the third lateral inner corner C3_in_top and the third bottom inner corner C3_in_btm are also different from those of the seventh embodiment. Other than these, the eighth embodiment is the same as the seventh embodiment.

The first lateral inner corner C1_in_top is connected to the inner surface of the first gap forming portion 111 and the inner surface of the first core lateral portion 1121, and forms an inclined surface that slopes with respect to the width direction DW and the thickness direction DT. The first bottom inner corner C1_in_btm is connected to the inner surface of the first core lateral portion 1121 and the inner surface of the first core bottom portion 1131, and forms an inclined surface that slopes with respect to the width direction DW and the thickness direction DT.

The second lateral inner corner C2_in_top is connected to the inner surface of the second gap forming portion 211 and the inner surface of the second core lateral portion 2122, and forms an inclined surface that slopes with respect to the width direction DW and the thickness direction DT. The second bottom inner corner C2_in_btm is connected to the inner surface of the second core lateral portion 2122 and the inner surface of the second core bottom portion 2132, and forms an inclined surface that slopes with respect to the width direction DW and the thickness direction DT.

The third lateral inner corner C3_in_top is connected to the inner surface of the third gap forming portion 311 and the inner surface of the third core lateral portion 3123, and forms an inclined surface that slopes with respect to the width direction DW and the thickness direction DT. The third bottom inner corner C3_in_btm is connected to the inner surface of the third core lateral portion 3123 and the inner surface of the third core bottom portion 3133, and forms an inclined surface that slopes with respect to the width direction DW and the thickness direction DT.

The current sensor 5 of the eighth embodiment is configured as described above. This eighth embodiment also achieves the same effects as the seventh embodiment.

Ninth Embodiment
13, the ninth embodiment differs from the first embodiment in the shapes of the first core 110, the second core 210, and the third core 310. Other than this, the ninth embodiment is similar to the first embodiment.

The first core 110 includes a first gap forming portion 111 and a first core hole 114, but includes a first core side portion 1121 and a first core bottom portion 1131 instead of the first easy axis portion 112 and the first hard axis portion 113.

The first core horizontal portion 1121 is connected to the first gap forming portion 111. The first core horizontal portion 1121 extends in the thickness direction DT from the boundary between the first core horizontal portion 1121 and the first gap forming portion 111. As described above, the first outer horizontal corner C1_out_top, which is the outer corner of the first gap forming portion 111 in the width direction DW, is rounded.

The first core bottom 1131 is connected to the first core horizontal portion 1121. Furthermore, the first core bottom 1131 extends in the width direction DW. The magnetic permeability of the first core bottom 1131 is smaller than that of the first core horizontal portion 1121. The saturation magnetic flux density of the first core bottom 1131 is smaller than that of the first core horizontal portion 1121. The length of the first core bottom 1131 in the thickness direction DT is longer than the length of the first core horizontal portion 1121 in the width direction DW. As described above, the first core hole 114 is a space formed by the first gap forming portion 111, the first core horizontal portion 1121, and the first core bottom 1131.

The second core 210 includes a second gap forming portion 211 and a second core hole 214, but includes a second core side portion 2122 and a second core bottom portion 2132 instead of the second easy axis portion 212 and the second hard axis portion 213.

The second core horizontal portion 2122 is connected to the second gap forming portion 211. The second core horizontal portion 2122 extends in the thickness direction DT from the boundary between the second core horizontal portion 2122 and the second gap forming portion 211. As described above, the second horizontal outer corner C2_out_top, which is the corner of the second gap forming portion 211 on the outer side in the width direction DW, is rounded. The second horizontal outer corner C2_out_top and the first horizontal outer corner C1_out_top face each other in the width direction DW.

The second core bottom 2132 is connected to the second core horizontal portion 2122. Furthermore, the second core bottom 2132 extends in the width direction DW. The magnetic permeability of the second core bottom 2132 is smaller than that of the second core horizontal portion 2122. The saturation magnetic flux density of the second core bottom 2132 is smaller than that of the second core horizontal portion 2122. The length of the second core bottom 2132 in the thickness direction DT is longer than the length of the second core horizontal portion 2122 in the width direction DW. As described above, the second core hole 214 is a space formed by the second gap forming portion 211, the second core horizontal portion 2122, and the second core bottom 2132.

The third core 310 includes a third gap forming portion 311 and a third core hole 314, but includes a third core side portion 3123 and a third core bottom portion 3133 instead of the third easy axis portion 312 and the third hard axis portion 313.

The third core horizontal portion 3123 is connected to the third gap forming portion 311. The third core horizontal portion 3123 extends in the thickness direction DT from the boundary between the third core horizontal portion 3123 and the third gap forming portion 311. As described above, the third horizontal outer corner C3_out_top, which is the corner of the third gap forming portion 311 on the outer side in the width direction DW, is rounded. Furthermore, the third horizontal outer corner C3_out_top and the second horizontal outer corner C2_out_top face each other in the width direction DW.

The third core bottom 3133 is connected to the third core horizontal portion 3123. Furthermore, the third core bottom 3133 extends in the width direction DW. The magnetic permeability of the third core bottom 3133 is smaller than that of the third core horizontal portion 3123. The saturation magnetic flux density of the third core bottom 3133 is smaller than that of the third core horizontal portion 3123. The length of the third core bottom 3133 in the thickness direction DT is longer than the length of the third core horizontal portion 3123 in the width direction DW. As described above, the third core hole 314 is a space formed by the third gap forming portion 311, the third core horizontal portion 3123, and the third core bottom 3133.

The current sensor 5 of the ninth embodiment is configured as described above. The ninth embodiment also achieves the same effects as the first embodiment. The ninth embodiment also achieves the effects described below.

[7] The first core 110, second core 210, and third core 310 are arranged in the width direction DW in the order of first core 110, second core 210, and third core 310. Furthermore, the first lateral outer corner C1_out_top and the second lateral outer corner C2_out_top, which face each other in the width direction DW, are rounded. This increases the maximum distance in the width direction DW between the first gap forming portion 111 and the second gap forming portion 211 compared to when they are not rounded. Furthermore, the second lateral outer corner C2_out_top and the third lateral outer corner C3_out_top, which face each other in the width direction DW, are rounded. This increases the maximum distance in the width direction DW between the second gap forming portion 211 and the third gap forming portion 311 compared to when they are not rounded. As a result, the magnetic resistance increases between adjacent first core 110 and second core 210, and between adjacent second core 210 and third core 310. This makes it difficult for a magnetic path to be formed between adjacent first core 110 and second core 210, and between adjacent second core 210 and third core 310. This suppresses a decrease in magnetic resistance across the entire first core 110, second core 210, and third core 310. This suppresses an increase in magnetic flux density in each of the first core 110, second core 210, and third core 310 due to the influence between adjacent cores, thereby suppressing magnetic saturation in each of the first core 110, second core 210, and third core 310.

Tenth Embodiment
14, the tenth embodiment differs from the ninth embodiment in the shapes of the first core 110, the second core 210, and the third core 310. Other than this, the tenth embodiment is similar to the ninth embodiment.

In addition to the first lateral outer corner C1_out_top, the first core 110 has a first bottom outer corner C1_out_btm. The first bottom outer corner C1_out_btm is the outer corner of the first core bottom 1131 in the width direction DW and is formed in an R-shape.

In addition to the second lateral outer corner C2_out_top, the second core 210 has a second bottom outer corner C2_out_btm. The second bottom outer corner C2_out_btm is the outer corner of the second core bottom 2132 in the width direction DW and is formed in an R-shape. The second bottom outer corner C2_out_btm and the first bottom outer corner C1_out_btm face each other in the width direction DW.

The third core 310 has a third bottom outer corner C3_out_btm in addition to a third lateral outer corner C3_out_top. The third bottom outer corner C3_out_btm is the outer corner of the third core bottom 3133 in the width direction DW and is formed in an R-shape. The third bottom outer corner C3_out_btm and the second bottom outer corner C2_out_btm face each other in the width direction DW.

The current sensor 5 of the tenth embodiment is configured as described above. The tenth embodiment also achieves the same effects as the ninth embodiment. The tenth embodiment also achieves the effects described below.

[8] The first bottom outer corner C1_out_btm and the second bottom outer corner C2_out_btm, which face each other in the width direction DW, are rounded. This increases the maximum distance in the width direction DW between the first core bottom 1131 and the second core bottom 2132 compared to when they are not rounded. Furthermore, the second bottom outer corner C2_out_btm and the third bottom outer corner C3_out_btm, which face each other in the width direction DW, are rounded. This increases the maximum distance in the width direction DW between the second core bottom 2132 and the third core bottom 3133 compared to when they are not rounded. As a result, the magnetic reluctance between the adjacent first core 110 and second core 210, and between the adjacent second core 210 and third core 310, is increased. Therefore, it is difficult for a magnetic path to be formed between the adjacent first core 110 and second core 210, and between the adjacent second core 210 and third core 310. This prevents a decrease in magnetic resistance across the entire first core 110, second core 210, and third core 310. This prevents an increase in magnetic flux density in each of the first core 110, second core 210, and third core 310 due to the influence between adjacent cores, thereby preventing magnetic saturation in each of the first core 110, second core 210, and third core 310.

Eleventh Embodiment
15 , the eleventh embodiment differs from the tenth embodiment in the first lateral outer corner C1_out_top and the first bottom outer corner C1_out_btm. The second lateral outer corner C2_out_top and the second bottom outer corner C2_out_btm also differ from the tenth embodiment. Furthermore, the shape of the third lateral outer corner C3_out_top and the third bottom outer corner C3_out_btm differs from the tenth embodiment. Other than these, the eleventh embodiment is the same as the tenth embodiment.

The first lateral outer corner C1_out_top is connected to the outer surface of the first gap forming portion 111 and the outer surface of the first core lateral portion 1121, and forms an inclined surface that slopes with respect to the width direction DW and the thickness direction DT. The first bottom outer corner C1_out_btm is connected to the outer surface of the first core lateral portion 1121 and the outer surface of the first core bottom portion 1131, and forms an inclined surface that slopes with respect to the width direction DW and the thickness direction DT.

The second lateral outer corner C2_out_top is connected to the outer surface of the second gap forming portion 211 and the outer surface of the second core lateral portion 2122, and forms an inclined surface that slopes relative to the width direction DW and the thickness direction DT. The second bottom outer corner C2_out_btm is connected to the outer surface of the second core lateral portion 2122 and the outer surface of the second core bottom portion 2132, and forms an inclined surface that slopes relative to the width direction DW and the thickness direction DT.

The third lateral outer corner C3_out_top is connected to the outer surface of the third gap forming portion 311 and the outer surface of the third core lateral portion 3123, and forms an inclined surface that slopes with respect to the width direction DW and the thickness direction DT. The third bottom outer corner C3_out_btm is connected to the outer surface of the third core lateral portion 3123 and the outer surface of the third core bottom portion 3133, and forms an inclined surface that slopes with respect to the width direction DW and the thickness direction DT.

The current sensor 5 of the 11th embodiment is configured as described above. This 11th embodiment also achieves the same effects as the 10th embodiment.

Twelfth Embodiment
In the twelfth embodiment, as shown in Figures 16 to 18, the shapes of the first core 110, the second core 210, and the third core 310 are different from those of the sixth embodiment. Other than these, the twelfth embodiment is the same as the sixth embodiment. Note that, to avoid complexity, the first bus bar 100, the second bus bar 200, the third bus bar 300, the case 70, and the like are not shown in Figures 16 to 18.

As shown in FIG. 16, the first core 110 includes a first gap forming portion 111, a first core side portion 1121, a first core bottom portion 1131, and a first core hole 114, as well as a first protrusion portion 1151 and a second protrusion portion 1152.

The first protrusion 1151 and the second protrusion 1152 protrude in the thickness direction DT from the outer surface of the first gap forming portion 111 facing outward in the thickness direction DT. Furthermore, the first protrusion surface 1161, which is the surface of the first protrusion 1151 facing inward in the width direction DW, is connected to the first core end surface 115. Furthermore, the second protrusion surface 1162, which is the surface of the second protrusion 1152 facing inward in the width direction DW, is connected to the second core end surface 116. Therefore, the first gap 117 is formed by the first core end surface 115, the second core end surface 116, the first protrusion surface 1161, and the second protrusion surface 1162. While the number of first protrusion 1151 and second protrusion 1152 is one each, this is not limited to one, and the number of each may be two or more. Furthermore, while the shapes of the first protrusion 1151 and the second protrusion 1152 are each a quadrangular prism, they are not limited to this and may each be a polygonal prism, a cylindrical shape, etc.

As shown in FIG. 17, the second core 210 includes a second gap forming portion 211, a second core side portion 2122, a second core bottom portion 2132, and a second core hole 214, as well as a third protrusion portion 2151 and a fourth protrusion portion 2152.

The third protrusion 2151 and the fourth protrusion 2152 protrude in the thickness direction DT from the outer surface of the second gap forming portion 211 facing outward in the thickness direction DT. Furthermore, the third protrusion surface 2161, which is the surface of the third protrusion 2151 facing inward in the width direction DW, is connected to the third core end surface 215. Furthermore, the fourth protrusion surface 2162, which is the surface of the fourth protrusion 2152 facing inward in the width direction DW, is connected to the fourth core end surface 216. Therefore, the second gap 217 is formed by the third core end surface 215, the fourth core end surface 2161, and the fourth protrusion surface 2162 in addition to the third core end surface 215. While the number of the third protrusion 2151 and the fourth protrusion 2152 is one each, this is not limited to one, and the number of each may be two or more. Furthermore, while the shapes of the third protrusion 2151 and the fourth protrusion 2152 are each a quadrangular prism, they are not limited to this and may each be a polygonal prism, a cylindrical shape, etc.

As shown in FIG. 18, the third core 310 includes a third gap forming portion 311, a third core side portion 3123, a third core bottom portion 3133, and a third core hole 314, as well as a fifth protrusion portion 3151 and a sixth protrusion portion 3152.

The fifth protrusion 3151 and the sixth protrusion 3152 protrude in the thickness direction DT from the outer surface of the third gap forming portion 311 facing outward in the thickness direction DT. Furthermore, the fifth protrusion surface 3161, which is the surface of the fifth protrusion 3151 facing inward in the width direction DW, is connected to the fifth core end surface 315. Furthermore, the sixth protrusion surface 3162, which is the surface of the sixth protrusion 3152 facing inward in the width direction DW, is connected to the sixth core end surface 316. Therefore, the third gap 317 is formed by the fifth core end surface 315, the sixth core end surface 316, the fifth protrusion surface 3161, and the sixth protrusion surface 3162. While the number of the fifth protrusion 3151 and the sixth protrusion 3152 is one each, this is not limited to one, and the number of each may be two or more. Furthermore, while the shapes of the fifth protrusion 3151 and the sixth protrusion 3152 are each a quadrangular prism, they are not limited to this and may each be a polygonal prism, a cylindrical shape, etc.

Here, in a cross section of the first core 110 when the first core 110 is cut in a direction perpendicular to the longitudinal direction DL, a line that passes through the inner edge of the first core horizontal portion 1121 extending in the thickness direction DT and extends in the thickness direction DT is defined as a first imaginary line L1. Also, in a cross section of the second core 210 when the second core 210 is cut in a direction perpendicular to the longitudinal direction DL, a line that passes through the inner edge of the second core horizontal portion 2122 extending in the thickness direction DT and extends in the thickness direction DT is defined as a second imaginary line L2. Furthermore, in a cross section of the third core 310 when the third core 310 is cut in a direction perpendicular to the longitudinal direction DL, a line that passes through the inner edge of the third core horizontal portion 3123 extending in the thickness direction DT and extends in the thickness direction DT is defined as a third imaginary line L3.

The first protrusion 1151 and the second protrusion 1152 are located inward in the width direction DW from the first imaginary line L1. The third protrusion 2151 and the fourth protrusion 2152 are located inward in the width direction DW from the second imaginary line L2. The fifth protrusion 3151 and the sixth protrusion 3152 are located inward in the width direction DW from the third imaginary line L3.

Here, the line passing through the center in the thickness direction DT of the surface where the first protrusion surface 1161 and the first core end surface 115 are joined and extending in the width direction DW is referred to as the first center line O1. Furthermore, the first center line O1 passes through the center in the thickness direction DT of the surface where the second protrusion surface 1162 and the second core end surface 116 are joined. Furthermore, the line passing through the center in the thickness direction DT of the surface where the third protrusion surface 2161 and the third core end surface 215 are joined and extending in the width direction DW is referred to as the second center line O2. Furthermore, the second center line O2 passes through the center in the thickness direction DT of the surface where the fourth protrusion surface 2162 and the fourth core end surface 216 are joined. Furthermore, the line passing through the center in the thickness direction DT of the surface where the fifth protrusion surface 3161 and the fifth core end surface 315 are joined and extending in the width direction DW is referred to as the third center line O3. Furthermore, the third center line O3 passes through the center in the thickness direction DT of the surface where the sixth protrusion surface 3162 and the sixth core end surface 316 meet.

The first detection unit 120 is positioned closer to the first core hole 114 than the first center line O1, and therefore the first detection unit 120 is positioned between the first center line O1 and the first bus bar 100 in the thickness direction DT. The second detection unit 220 is positioned closer to the second core hole 214 than the second center line O2, and therefore the second detection unit 220 is positioned between the second center line O2 and the second bus bar 200 in the thickness direction DT. The third detection unit 320 is positioned closer to the third core hole 314 than the third center line O3, and therefore the third detection unit 320 is positioned between the third center line O3 and the third bus bar 300 in the thickness direction DT.

The current sensor 5 of the twelfth embodiment is configured as described above. This twelfth embodiment also provides the same advantages as the sixth embodiment. The twelfth embodiment also provides the following advantages.

[9-1] Here, when the first detection unit 120 detects the strength of the magnetic field at the first gap 117, it may erroneously detect the strength of a disturbance magnetic field, for example, the strength of a magnetic field caused by magnetic field lines leaking from the second core 210. Furthermore, when the second detection unit 220 detects the strength of the magnetic field at the second gap 217, it may erroneously detect the strength of a disturbance magnetic field, for example, the strength of a magnetic field caused by magnetic field lines leaking from the first core 110 and the third core 310. Furthermore, when the third detection unit 320 detects the strength of the magnetic field at the third gap 317, it may erroneously detect the strength of a disturbance magnetic field, for example, the strength of a magnetic field caused by magnetic field lines leaking from the second core 210.

In response to this, it is conceivable that reducing the size of the first gap 117, the second gap 217, and the third gap 317 would make them less susceptible to the effects of disturbance magnetic fields. However, reducing the size of the first gap 117, the second gap 217, and the third gap 317 would also reduce the size of the first core 110, the second core 210, and the third core 310. This would reduce the magnetic resistance of the first core 110, the second core 210, and the third core 310, thereby increasing the magnetic flux density acting on the first core 110, the second core 210, and the third core 310. This would make magnetic saturation of the first core 110, the second core 210, and the third core 310 more likely to occur.

Therefore, the first core 110 has a first protrusion 1151 and a second protrusion 1152. The first protrusion 1151 and the second protrusion 1152 protrude from the first gap forming portion 111 in the thickness direction DT. This reduces the magnetic resistance of the first gap forming portion 111 relative to the magnetic resistance of the entire first core 110 compared to when the first protrusion 1151 and the second protrusion 1152 are not present. This makes it easier for magnetic field lines due to disturbance magnetic fields, such as magnetic field lines leaking from the second core 210, to pass through the first gap forming portion 111 via the first protrusion 1151 and the second protrusion 1152 without passing through the first detection portion 120. This reduces the influence of disturbance magnetic fields on the first detection portion 120, improving the detection accuracy of the first detection portion 120. Furthermore, the first protrusion 1151 and the second protrusion 1152 increase the size of the first gap 117 compared to when the first protrusion 1151 and the second protrusion 1152 are not present, thereby increasing the magnetic resistance of the first core 110. This prevents an increase in the magnetic flux density of the first core 110. Furthermore, the first protrusion 1151 and the second protrusion 1152 eliminate the need to increase the overall size of the first core 110. This prevents the first core 110 from becoming too large, while also preventing magnetic saturation of the first core 110.

The second core 210 also has a third protrusion 2151 and a fourth protrusion 2152. The third protrusion 2151 and the fourth protrusion 2152 protrude from the second gap forming portion 211 in the thickness direction DT. This reduces the magnetic resistance of the second gap forming portion 211 relative to the magnetic resistance of the entire second core 210 compared to when the third protrusion 2151 and the fourth protrusion 2152 are not present. This makes it easier for magnetic field lines caused by disturbance magnetic fields, such as magnetic field lines leaking from the first core 110 and the third core 310, to pass through the second gap forming portion 211 via the third protrusion 2151 and the fourth protrusion 2152 without passing through the second detection portion 220. This reduces the influence of disturbance magnetic fields on the second detection portion 220, improving the detection accuracy of the second detection portion 220. Additionally, the third protrusion 2151 and the fourth protrusion 2152 increase the size of the second gap 217 compared to when the third protrusion 2151 and the fourth protrusion 2152 are not present, thereby increasing the magnetic resistance of the second core 210. This suppresses an increase in the magnetic flux density of the second core 210. Furthermore, the third protrusion 2151 and the fourth protrusion 2152 eliminate the need to increase the overall size of the second core 210. This suppresses an increase in the size of the second core 210 while suppressing magnetic saturation of the second core 210.

Furthermore, the third core 310 has a fifth protrusion 3151 and a sixth protrusion 3152. The fifth protrusion 3151 and the sixth protrusion 3152 protrude from the third gap forming portion 311 in the thickness direction DT. This reduces the magnetic resistance of the third gap forming portion 311 relative to the magnetic resistance of the entire third core 310 compared to when the fifth protrusion 3151 and the sixth protrusion 3152 are not present. This makes it easier for magnetic field lines caused by a disturbance magnetic field, such as magnetic field lines leaking from the second core 210, to pass through the third gap forming portion 311 via the fifth protrusion 3151 and the sixth protrusion 3152 without passing through the third detection portion 320. This reduces the influence of the disturbance magnetic field on the third detection portion 320, improving the detection accuracy of the third detection portion 320. Furthermore, the fifth protrusion 3151 and the sixth protrusion 3152 increase the size of the third gap 317 compared to when the fifth protrusion 3151 and the sixth protrusion 3152 are not present, thereby increasing the magnetic resistance of the third core 310. This suppresses an increase in the magnetic flux density of the third core 310. Furthermore, the fifth protrusion 3151 and the sixth protrusion 3152 eliminate the need to increase the overall size of the third core 310. This suppresses an increase in the size of the third core 310 while suppressing magnetic saturation of the third core 310.

[9-2] The first detection unit 120 is disposed between the first center line O1 and the first bus bar 100 in the thickness direction DT. As a result, the first detection unit 120 is separated from the outside of the first core 110 in the thickness direction DT, making it difficult for magnetic field lines due to a disturbance magnetic field to pass through the first detection unit 120. Therefore, the first detection unit 120 is less susceptible to the influence of the disturbance magnetic field, improving the detection accuracy of the first detection unit 120. Furthermore, the second detection unit 220 is disposed between the second center line O2 and the second bus bar 200 in the thickness direction DT. As a result, the second detection unit 220 is separated from the outside of the second core 210 in the thickness direction DT, making it difficult for magnetic field lines due to a disturbance magnetic field to pass through the second detection unit 220. Therefore, the second detection unit 220 is less susceptible to the influence of the disturbance magnetic field, improving the detection accuracy of the second detection unit 220. Furthermore, the third detection unit 320 is disposed between the third center line O3 and the third bus bar 300 in the thickness direction DT. As a result, the third detection unit 320 is separated from the outside of the third core 310 in the thickness direction DT, making it difficult for magnetic field lines due to disturbance magnetic fields to pass through the third detection unit 320. As a result, the third detection unit 320 is less susceptible to the effects of disturbance magnetic fields, improving the detection accuracy of the third detection unit 320.

Thirteenth Embodiment
19 to 21 , the thirteenth embodiment differs from the twelfth embodiment in the shapes of the first protrusion 1151, the second protrusion 1152, the third protrusion 2151, the fourth protrusion 2152, the fifth protrusion 3151, and the sixth protrusion 3152. Other than these, the thirteenth embodiment is the same as the twelfth embodiment. Note that in FIGS. 19 to 21 , the first bus bar 100, the second bus bar 200, the third bus bar 300, the case 70, and the like are not shown to avoid complication.

The first protrusion surface 1161 and the second protrusion surface 1162 are not connected to the first core end surface 115 and the second core end surface 116, but are connected to the outer surface of the first gap forming portion 111 facing outward in the thickness direction DT. Furthermore, the third protrusion portion 2151 and the fourth protrusion portion 2152 are not connected to the third core end surface 215 and the fourth core end surface 216, but are connected to the outer surface of the second gap forming portion 211 facing outward in the thickness direction DT. Furthermore, the fifth protrusion portion 3151 and the sixth protrusion portion 3152 are not connected to the fifth core end surface 315 and the sixth core end surface 316, but are connected to the outer surface of the third gap forming portion 311 facing outward in the thickness direction DT.

The current sensor 5 of the thirteenth embodiment is configured as described above. This thirteenth embodiment also achieves the same effects as the twelfth embodiment.

(Fourteenth embodiment)
In the fourteenth embodiment, as shown in Figures 22 to 24, the shapes of the first protrusion 1151, the second protrusion 1152, the third protrusion 2151, the fourth protrusion 2152, the fifth protrusion 3151, and the sixth protrusion 3152 are different from those of the twelfth embodiment. Other than these, the fourteenth embodiment is the same as the twelfth embodiment. Note that, to avoid complexity, the first bus bar 100, the second bus bar 200, the third bus bar 300, the case 70, and the like are not shown in Figures 22 to 24.

The first protrusion 1151 and the second protrusion 1152 protrude in the thickness direction DT from the inner surface of the first gap forming portion 111 facing inward in the thickness direction DT. The third protrusion 2151 and the fourth protrusion 2152 protrude in the thickness direction DT from the inner surface of the second gap forming portion 211 facing inward in the thickness direction DT. The fifth protrusion 3151 and the sixth protrusion 3152 protrude in the thickness direction DT from the inner surface of the third gap forming portion 311 facing inward in the thickness direction DT.

The current sensor 5 of the fourteenth embodiment is configured as described above. In this case, magnetic field lines caused by a disturbance magnetic field tend to pass through the first gap forming portion 111 from the outside without passing through the first protrusion 1151 and the second protrusion 1152. Furthermore, magnetic field lines caused by a disturbance magnetic field tend to pass through the second gap forming portion 211 from the outside without passing through the third protrusion 2151 and the fourth protrusion 2152. Furthermore, magnetic field lines caused by a disturbance magnetic field tend to pass through the third gap forming portion 311 without passing through the fifth protrusion 3151 and the sixth protrusion 3152. Therefore, the fourteenth embodiment also achieves the same effects as the twelfth embodiment.

Fifteenth Embodiment
As shown in Figures 25 to 27, the fifteenth embodiment differs from the sixth embodiment in the shapes of the first core 110, the second core 210, and the third core 310. Other than this, the fifteenth embodiment is similar to the sixth embodiment. Note that, to avoid complexity, the first bus bar 100, the second bus bar 200, the third bus bar 300, the first detector 120, the second detector 220, the third detector 320, the case 70, and the like are not shown in Figures 25 to 27.

As shown in FIG. 25, the first core 110 includes a first gap forming portion 111, a first core side portion 1121, a first core bottom portion 1131, a first core hole 114, and a first core recess 1155.

In a cross section of the first core 110 taken in a direction perpendicular to the longitudinal direction DL, the first core recess 1155 is recessed from the outer edge of the first core 110 on the outside in the width direction DW and thickness direction DT toward the inside of the first core 110. For example, in the cross section, the first core recess 1155 is recessed from the outer edges of the first gap forming portion 111 and the first core horizontal portion 1121 on the outside in the width direction DW toward the inside of the first core 110. Note that the first core recess 1155 may be recessed from the outer edges of the first gap forming portion 111 and the first core horizontal portion 1121 in the cross section, but is not limited to this. The first core recess 1155 may also be recessed from the outer edge of the first core bottom portion 1131 in the cross section. While the number of first core recesses 1155 is two, it is not limited to this and at least one is sufficient. Furthermore, while the cross-sectional shape of the first core recess 1155 is rectangular, it is not limited to this and may be, for example, polygonal or arc-shaped.

As shown in FIG. 26, the second core 210 includes a second gap forming portion 211, a second core side portion 2122, a second core bottom portion 2132, a second core hole 214, and a second core recess 2155.

In a cross section of the second core 210 taken in a direction perpendicular to the longitudinal direction DL, the second core recess 2155 is recessed from the outer edge of the second core 210 on the outside in the width direction DW and thickness direction DT toward the inside of the second core 210. For example, in the cross section, the second core recess 2155 is recessed from the outer edges of the second gap forming portion 211 and the second core horizontal portion 2122 on the outside in the width direction DW toward the inside of the second core 210. Note that the second core recess 2155 may be recessed from the outer edges of the second gap forming portion 211 and the second core horizontal portion 2122 in the cross section, but is not limited to this. The second core recess 2155 may also be recessed from the outer edge of the second core bottom portion 2132 in the cross section. While the number of second core recesses 2155 is two, it is not limited to this and at least one is sufficient. Furthermore, while the cross-sectional shape of the second core recess 2155 is rectangular, it is not limited to this and may be, for example, polygonal or arc-shaped.

As shown in FIG. 27, the third core 310 includes a third gap forming portion 311, a third core side portion 3123, a third core bottom portion 3133, a third core hole 314, and a third core recess 3155.

In a cross section of the third core 310 taken in a direction perpendicular to the longitudinal direction DL, the third core recess 3155 is recessed from the outer edge of the third core 310 on the outside in the width direction DW and thickness direction DT toward the inside of the third core 310. For example, in the cross section, the third core recess 3155 is recessed from the outer edges of the third gap forming portion 311 and the third core horizontal portion 3123 on the outside in the width direction DW toward the inside of the third core 310. Note that the third core recess 3155 may be recessed from the outer edges of the third gap forming portion 311 and the third core horizontal portion 3123 in the cross section, but is not limited to this. The third core recess 3155 may also be recessed from the outer edge of the third core bottom portion 3133 in the cross section. While the number of third core recesses 3155 is two, it is not limited to this and at least one is sufficient. Furthermore, while the cross-sectional shape of the third core recess 3155 is rectangular, it is not limited to this and may be, for example, polygonal or arc-shaped.

Here, as shown in FIG. 25, in a cross section of the first core 110 taken in a direction perpendicular to the longitudinal direction DL, a line segment passing through the center of the first gap forming portion 111 in the thickness direction DT and extending in the width direction DW is defined as the first gap center line segment Og1. A line segment passing through the center of the first core horizontal portion 1121 in the width direction DW and extending in the thickness direction DT is defined as the first horizontal center line segment Os1. A line segment passing through the center of the first core bottom portion 1131 in the thickness direction DT and extending in the width direction DW is defined as the first bottom center line segment Ob1. The first gap center line segment Og1 is a line segment connecting the first horizontal center line segments Os1 aligned in the width direction DW. Furthermore, the first horizontal center line segment Os1 is a line segment connecting the first gap center line segment Og1 and the first bottom center line segment Ob1. The first bottom center line segment Ob1 is a line segment connecting the first horizontal center line segment Os1 aligned in the width direction DW. Furthermore, the region outside the first gap center line segment Og1, the first horizontal center line segment Os1, and the first bottom center line segment Ob1 is defined as the first core region Rc1.

As shown in FIG. 26 , in a cross section of the second core 210 taken in a direction perpendicular to the longitudinal direction DL, a line segment passing through the center of the second gap forming portion 211 in the thickness direction DT and extending in the width direction DW is defined as the second gap center line segment Og2. Furthermore, a line segment passing through the center of the second core horizontal portion 2122 in the width direction DW and extending in the thickness direction DT is defined as the second horizontal center line segment Os2. Furthermore, a line segment passing through the center of the second core bottom portion 2132 in the thickness direction DT and extending in the width direction DW is defined as the second bottom center line segment Ob2. Furthermore, the second gap center line segment Og2 is a line segment connecting the second horizontal center line segments Os2 aligned in the width direction DW. Furthermore, the second horizontal center line segment Os2 is a line segment connecting the second gap center line segment Og2 and the second bottom center line segment Ob2. Furthermore, the second bottom center line segment Ob2 is a line segment connecting the second horizontal center line segment Os2 aligned in the width direction DW. The region outside the second gap center line segment Og2, the second horizontal center line segment Os2, and the second bottom center line segment Ob2 is defined as the second core region Rc2.

Furthermore, as shown in FIG. 27 , in a cross section of the third core 310 taken in a direction perpendicular to the longitudinal direction DL, a line segment passing through the center of the third gap forming portion 311 in the thickness direction DT and extending in the width direction DW is defined as the third gap center line segment Og3. A line segment passing through the center of the third core horizontal portion 3123 in the width direction DW and extending in the thickness direction DT is defined as the third horizontal center line segment Os3. A line segment passing through the center of the third core bottom portion 3133 in the thickness direction DT and extending in the width direction DW is defined as the third bottom center line segment Ob3. The third gap center line segment Og3 is a line segment connecting the third horizontal center line segments Os3 aligned in the width direction DW. Furthermore, the third horizontal center line segment Os3 is a line segment connecting the third gap center line segment Og3 and the third bottom center line segment Ob3. The third bottom center line segment Ob3 is a line segment connecting the third horizontal center line segment Os3 aligned in the width direction DW. Furthermore, the region outside the third gap center line segment Og3, the third horizontal center line segment Os3, and the third bottom center line segment Ob3 is defined as the third core region Rc3.

The first core recess 1155 is located in the first core region Rc1. The second core recess 2155 is located in the second core region Rc2. The third core recess 3155 is located in the third core region Rc3.

The current sensor 5 of the fifteenth embodiment is configured as described above. This fifteenth embodiment also provides the same advantages as the sixth embodiment. The fifteenth embodiment also provides the following advantages.

[10-1] Here, when the case 70 is injection molded or otherwise processed, stress is applied to the first core 110, second core 210, and third core 310. This may cause the crystal structure of the first core 110, second core 210, and third core 310 to change. This may cause the magnetic characteristics, such as the BH characteristics, of the first core 110, second core 210, and third core 310 to deteriorate; for example, the linear range of magnetic flux density relative to magnetic field strength may become smaller. Note that the B in the BH characteristics stands for magnetic flux density. The H in the BH characteristics stands for magnetic field.

In contrast, the first core 110 includes a first core recess 1155. In a cross section of the first core 110 taken in a direction perpendicular to the longitudinal direction DL, the first core recess 1155 is recessed from the outer edge of the first core 110 on the outside in the width direction DW and thickness direction DT toward the inside of the first core 110. This reduces stress applied to the first core 110. This suppresses changes in the crystal structure of the first core 110, thereby suppressing deterioration of the magnetic characteristics of the first core 110. Furthermore, the second core 210 includes a second core recess 2155. In a cross section of the second core 210 taken in a direction perpendicular to the longitudinal direction DL, the second core recess 2155 is recessed from the outer edge of the second core 210 on the outside in the width direction DW and thickness direction DT toward the inside of the second core 210. This reduces stress applied to the second core 210. This suppresses changes in the crystal structure of the second core 210, thereby suppressing deterioration in the magnetic properties of the second core 210. Furthermore, the third core 310 includes a third core recess 3155. In a cross section of the third core 310 taken in a direction perpendicular to the longitudinal direction DL, the third core recess 3155 is recessed from the outer edge of the third core 310 on the outside in the width direction DW and thickness direction DT toward the inside of the third core 310. This relieves stress acting on the third core 310. This suppresses changes in the crystal structure of the third core 310, thereby suppressing deterioration in the magnetic properties of the third core 310.

[10-2] The first core recess 1155 is located in the first core region Rc1, where the magnetic field lines of the first core 110 can easily pass through the inside of the first core 110. As a result, the first core recess 1155 is located in a position where the magnetic field lines of the first core 110 cannot easily pass through, thereby preventing the first core recess 1155 from blocking the passage of the magnetic field lines within the first core 110. Furthermore, the second core recess 2155 is located in the second core region Rc2, where the magnetic field lines of the second core 210 can easily pass through the inside of the second core 210. As a result, the second core recess 2155 is located in a position where the magnetic field lines of the second core 210 cannot easily pass through, thereby preventing the second core recess 2155 from blocking the passage of the magnetic field lines of the second core 210. Furthermore, the third core recess 3155 is located in the third core region Rc3, where the magnetic field lines of the third core 310 can easily pass through the inside of the third core 310. This positions the third core recess 3155 in a position where the magnetic field lines of the third core 310 have difficulty passing through, preventing the third core recess 3155 from interfering with the passage of the magnetic field lines inside the third core 310.

[10-3] The case 70 covers the first core 110, the second core 210, and the third core 310, and contacts the first core recess 1155, the second core recess 2155, and the third core recess 3155. This increases the contact area between the case 70 and the first core 110, the second core 210, and the third core 310 compared to when the first core recess 1155, the second core recess 2155, and the third core recess 3155 are not present. This makes it easier for the case 70 to support the first core 110, the second core 210, and the third core 310, reducing misalignment of the relative positions of the first core 110, the second core 210, and the third core 310 with respect to the case 70 in the width direction DW and the thickness direction DT.

Sixteenth Embodiment
In the sixteenth embodiment, as shown in Figures 28 to 30, the first core 110 includes a first core through hole 1156 instead of the first core recess 1155. The second core 210 includes a second core through hole 2156 instead of the second core recess 2155. The third core 310 includes a third core through hole 3156 instead of the third core recess 3155. Other than these, the sixteenth embodiment is the same as the fifteenth embodiment. Note that in Figures 28 to 30, to avoid complexity, the first bus bar 100, the second bus bar 200, the third bus bar 300, the first detector 120, the second detector 220, the third detector 320, the case 70, and the like are not shown.

The first core through hole 1156 penetrates in the longitudinal direction DL. The first core through hole 1156 is located in the first core region Rc1 and is formed, for example, inside the first gap forming portion 111. The first core through hole 1156 may be formed in the first gap forming portion 111, but is not limited to this. The first core through hole 1156 may also be formed in the first core lateral portion 1121 and the first core bottom portion 1131. The number of first core through holes 1156 is one, but is not limited to this and may be two or more. The cross-sectional shape of the first core through hole 1156 is circular, but is not limited to this and may be polygonal, elliptical, or the like.

The second core through hole 2156 penetrates in the longitudinal direction DL. The second core through hole 2156 is located in the second core region Rc2 and is formed, for example, inside the second gap forming portion 211. The second core through hole 2156 may be formed in the second gap forming portion 211, but is not limited to this. The second core through hole 2156 may also be formed in the second core lateral portion 2122 and the second core bottom portion 2132. The number of second core through holes 2156 is one, but is not limited to this and may be two or more. The cross-sectional shape of the second core through hole 2156 is circular, but is not limited to this and may be polygonal, elliptical, or the like.

The third core through hole 3156 penetrates in the longitudinal direction DL. The third core through hole 3156 is located in the third core region Rc3 and is formed, for example, inside the third gap forming portion 311. The third core through hole 3156 may be formed in the third gap forming portion 311, but is not limited to this. The third core through hole 3156 may also be formed in the third core lateral portion 3123 and the third core bottom portion 3133. The number of third core through holes 3156 is one, but is not limited to this and may be two or more. The cross-sectional shape of the third core through hole 3156 is circular, but is not limited to this and may be polygonal, elliptical, or the like.

The current sensor 5 of the 16th embodiment is configured as described above. This 16th embodiment also achieves the same effects as the 15th embodiment.

Seventeenth Embodiment
As shown in Fig. 31 , the seventeenth embodiment differs from the fifteenth embodiment in the shapes of the first core recess 1155, the second core recess 2155, and the third core recess 3155. Other than these, the seventeenth embodiment is similar to the fifteenth embodiment. Note that in Fig. 31 , to avoid complexity, the first bus bar 100, the second bus bar 200, the third bus bar 300, the first detector 120, the second detector 220, the third detector 320, the case 70, and the like are not shown.

In a cross section of the first core 110 taken in a direction perpendicular to the longitudinal direction DL, the first core recess 1155 is recessed from the outer edge of the first core 110 that faces the second core 210 in the width direction DW toward the inside of the first core 110. Specifically, the first core recess 1155 is recessed from the outer edges of the first gap forming portion 111, the first core lateral portion 1121, and the first core bottom portion 1131 that face the second core 210 in the width direction DW toward the inside of the first core 110. While the number of first core recesses 1155 is two, this is not a limitation and at least one is sufficient. Furthermore, while the cross-sectional shape of the first core recess 1155 is rectangular, this is not a limitation and may be polygonal, arc-shaped, or the like.

In a cross section of the second core 210 taken in a direction perpendicular to the longitudinal direction DL, the second core recess 2155 is recessed from the outer edge of the second core 210 that faces the first core 110 in the width direction DW toward the inside of the second core 210. Specifically, in the cross section, the second core recess 2155 is recessed from the outer edges of the second gap forming portion 211, the second core lateral portion 2122, and the second core bottom portion 2132 that face the first core 110 in the width direction DW toward the inside of the second core 210. Furthermore, in the cross section, the second core recess 2155 is recessed from the outer edge of the second core 210 that faces the third core 310 in the width direction DW toward the inside of the second core 210. Specifically, the second core recess 2155 is recessed in cross section from the outer edges of the second gap forming portion 211, second core lateral portion 2122, and second core bottom portion 2132, which face the third core 310 in the width direction DW, toward the inside of the second core 210. The number of second core recesses 2155 is four, but is not limited to this, as long as there is at least one on each of the first core 110 side and the third core 310 side. Furthermore, the cross-sectional shape of the second core recess 2155 is rectangular, but is not limited to this, and may be polygonal, arc-shaped, etc.

In a cross section of the third core 310 taken in a direction perpendicular to the longitudinal direction DL, the third core recess 3155 is recessed from the outer edge of the third core 310 that faces the second core 210 in the width direction DW toward the inside of the third core 310. Specifically, the third core recess 3155 is recessed from the outer edges of the third gap forming portion 311, the third core lateral portion 3123, and the third core bottom portion 3133 that face the second core 210 in the width direction DW toward the inside of the third core 310. While the number of third core recesses 3155 is two, this is not a limitation and at least one is sufficient. Furthermore, while the cross-sectional shape of the third core recess 3155 is rectangular, this is not a limitation and may be polygonal, arc-shaped, or the like.

The first core recess 1155 is located outward in the width direction DW from the first horizontal center line segment Os1. The second core recess 2155 is located outward in the width direction DW from the second horizontal center line segment Os2. The third core recess 3155 is located outward in the width direction DW from the third horizontal center line segment Os3.

The current sensor 5 of the 17th embodiment is configured as described above. This 17th embodiment also provides the same advantages as the 15th embodiment. The 17th embodiment also provides the following advantages.

[11] Here, in order to suppress magnetic saturation of the first core horizontal portion 1121, the second core horizontal portion 2122, and the third core horizontal portion 3123, it is possible to increase the lengths of the first core horizontal portion 1121, the second core horizontal portion 2122, and the third core horizontal portion 3123 in the width direction DW. In this case, when the first core 110, the second core 210, and the third core 310 are aligned in order in the width direction DW, adjacent cores tend to approach each other, reducing the magnetic resistance between the adjacent cores. This makes it easier for a magnetic path to be formed between the adjacent cores, reducing the magnetic resistance throughout the first core 110, the second core 210, and the third core 310. As a result, the magnetic flux density of each of the first core 110, the second core 210, and the third core 310 tends to increase, making magnetic saturation more likely to occur in each of the first core 110, the second core 210, and the third core 310.

In contrast, the first core 110 includes a first core recess 1155. In a cross section of the first core 110 taken in a direction perpendicular to the longitudinal direction DL, the first core recess 1155 is recessed from the outer edge of the first core 110 that faces the second core 210 in the width direction DW toward the inside of the first core 110. Furthermore, the second core 210 includes a second core recess 2155. In a cross section of the second core 210 taken in a direction perpendicular to the longitudinal direction DL, the second core recess 2155 is recessed from the outer edge of the second core 210 that faces the first core 110 or the third core 310 in the width direction DW toward the inside of the second core 210. Furthermore, the third core 310 includes a third core recess 3155. The third core recess 3155 is recessed from the outer edge of the third core 310 that faces the second core 210 in the width direction DW toward the inside of the third core 310 in a cross section of the third core 310 when the third core 310 is cut in a direction perpendicular to the longitudinal direction DL.

This increases the maximum distance in the width direction DW between adjacent first cores 110 and 210, and between adjacent second cores 210 and 310. This increases the magnetic resistance between adjacent first cores 110 and 210, and between adjacent second cores 210 and 310. This makes it difficult for a magnetic path to be formed between adjacent first cores 110 and 210, and between adjacent second cores 210 and 310. This suppresses a decrease in magnetic resistance throughout the first core 110, second core 210, and third core 310. This suppresses an increase in magnetic flux density in each of the first core 110, second core 210, and third core 310, thereby suppressing magnetic saturation in each of the first core 110, second core 210, and third core 310.

(18th embodiment)
In the eighteenth embodiment, as shown in Fig. 32 , the first core 110 includes a first core through hole 1156 instead of the first core recess 1155. The second core 210 includes a second core through hole 2156 instead of the second core recess 2155. The third core 310 includes a third core through hole 3156 instead of the third core recess 3155. Other than these, the eighteenth embodiment is the same as the seventeenth embodiment. Note that in Fig. 32 , to avoid complexity, the first bus bar 100, the second bus bar 200, the third bus bar 300, the first detector 120, the second detector 220, the third detector 320, the case 70, and the like are not shown.

The first core through hole 1156 penetrates in the longitudinal direction DL. The first core through hole 1156 is located outward in the width direction DW from the first horizontal center line segment Os1 and is formed in the first core horizontal portion 1121 and the first core bottom portion 1131, which face the second core 210 in the width direction DW. While the first core through hole 1156 is formed in the first core horizontal portion 1121 and the first core bottom portion 1131, this is not a limitation and the first core through hole 1156 may be formed in the first gap forming portion 111, which faces the second core 210 in the width direction DW. The number of first core through holes 1156 is two, but is not limited to this and may be at least one. The cross-sectional shape of the first core through hole 1156 is circular, but is not limited to this and may be polygonal, elliptical, or other shapes.

The second core through hole 2156 penetrates in the longitudinal direction DL. The second core through hole 2156 is located outward in the width direction DW from the second horizontal center line segment Os2 and is formed in the second core horizontal portion 2122 and the second core bottom portion 2132 that face the first core 110 in the width direction DW. The second core through hole 2156 is located outward in the width direction DW from the second horizontal center line segment Os2 and is formed in the second core horizontal portion 2122 and the second core bottom portion 2132 that face the third core 310 in the width direction DW. While the second core through hole 2156 is formed in the second core horizontal portion 2122 and the second core bottom portion 2132, this is not limiting. The second core through hole 2156 may also be formed in the second gap forming portion 211 that faces the first core 110 in the width direction DW. Furthermore, the second core through hole 2156 may be formed in the second gap forming portion 211 that faces the third core 310 in the width direction DW. Although the number of second core through holes 2156 is four, this is not limited to four, and there may be at least one on each of the first core 110 side and the third core 310 side. Furthermore, although the cross-sectional shape of the second core through hole 2156 is circular, this is not limited to four, and it may be polygonal, elliptical, or the like.

The third core through hole 3156 penetrates in the longitudinal direction DL. The third core through hole 3156 is located outward in the width direction DW from the third horizontal center line segment Os3 and is formed in the third core horizontal portion 3123 and the third core bottom portion 3133, which face the second core 210 in the width direction DW. While the third core through hole 3156 is formed in the third core horizontal portion 3123 and the third core bottom portion 3133, this is not a limitation and the third core through hole 3156 may be formed in the third gap forming portion 311, which faces the second core 210 in the width direction DW. The number of third core through holes 3156 is two, but is not limited to this and may be at least one. The cross-sectional shape of the third core through hole 3156 is circular, but is not limited to this and may be polygonal, elliptical, or other shapes.

The current sensor 5 of the 18th embodiment is configured as described above. This 18th embodiment also achieves the same effects as the 17th embodiment.

Nineteenth Embodiment
The nineteenth embodiment is a combination of the fifteenth and seventeenth embodiments.

Specifically, as shown in FIG. 33, the first core 110 includes a first gap forming portion 111, a first core horizontal portion 1121, a first core bottom portion 1131, a first core hole 114, and a first core recess 1155. Note that in FIG. 33, to avoid complexity, the first bus bar 100, the second bus bar 200, the third bus bar 300, the first detection portion 120, the second detection portion 220, the third detection portion 320, the case 70, and other components are not shown.

In a cross section of the first core 110 when the first core 110 is cut in a direction perpendicular to the longitudinal direction DL, the first core recess 1155 is recessed from the outer edges of the first gap forming portion 111 and the first core horizontal portion 1121 on the outer side in the width direction DW toward the inside of the first core 110. The first core recess 1155 is located further outward in the width direction DW than the first horizontal center line segment Os1. The cross-sectional shape of the first core recess 1155 is an arc shape. While the cross-sectional shape of the first core recess 1155 is an arc shape, it is not limited to this and may be, for example, a polygonal shape.

The second core 210 includes a second gap forming portion 211, a second core side portion 2122, a second core bottom portion 2132, a second core hole 214, and a second core recess 2155.

In a cross section of the second core 210 when the second core 210 is cut in a direction perpendicular to the longitudinal direction DL, the second core recess 2155 is recessed from the outer edges of the second gap forming portion 211 and the second core horizontal portion 2122 on the outer side in the width direction DW toward the inside of the second core 210. The second core recess 2155 is also located further outward in the width direction DW than the second horizontal center line segment Os2. The cross-sectional shape of the second core recess 2155 is an arc shape. Note that while the cross-sectional shape of the second core recess 2155 is an arc shape, it is not limited to this and may be, for example, a polygonal shape.

The third core 310 includes a third gap forming portion 311, a third core side portion 3123, a third core bottom portion 3133, a third core hole 314, and a third core recess 3155.

In a cross section of the third core 310 when the third core 310 is cut in a direction perpendicular to the longitudinal direction DL, the third core recess 3155 is recessed from the outer edges of the third gap forming portion 311 and the third core horizontal portion 3123 on the outer side in the width direction DW toward the inside of the third core 310. The third core recess 3155 is also located further outward in the width direction DW than the third horizontal center line segment Os3. The cross-sectional shape of the third core recess 3155 is an arc shape. Note that while the cross-sectional shape of the third core recess 3155 is an arc shape, it is not limited to this and may be, for example, a polygonal shape.

The first core 110, second core 210, and third core 310 are formed to have the same shape. Furthermore, the second core 210 is located between the first core 110 and the third core 310 in the width direction DW. Furthermore, when the second core recess 2155 on the first core 110 side is projected in the width direction DW, the first core recess 1155 on the second core 210 side overlaps with the projected second core recess 2155. Furthermore, when the second core recess 2155 on the third core 310 side is projected in the width direction DW, the third core recess 3155 on the second core 210 side overlaps with the projected second core recess 2155. As a result, the maximum distance in the width direction DW between the adjacent first core 110 and second core 210, and between the adjacent second core 210 and third core 310, is greater than when they do not overlap. This increases the magnetic resistance between adjacent first core 110 and second core 210, and between adjacent second core 210 and third core 310. This makes it difficult for a magnetic path to be formed between adjacent first core 110 and second core 210, and between adjacent second core 210 and third core 310. This suppresses a decrease in magnetic resistance throughout the first core 110, second core 210, and third core 310. This suppresses an increase in the magnetic flux density of each of the first core 110, second core 210, and third core 310, thereby suppressing magnetic saturation in each of the first core 110, second core 210, and third core 310.

The current sensor 5 of the 19th embodiment is configured as described above. This 19th embodiment also achieves the same effects as the 15th and 17th embodiments. The 19th embodiment also achieves the effects described below.

[12] The first core 110, second core 210, and third core 310 are formed to have the same shape.

This makes it easier to manufacture the first core 110, second core 210, and third core 310 when manufacturing the current sensor 5. This makes it easier to manufacture the current sensor 5.

Twentieth Embodiment
The twentieth embodiment is a combination of the sixteenth and eighteenth embodiments.

Specifically, as shown in FIG. 34 , the first core 110 includes a first core through hole 1156 instead of the first core recess 1155. The first core through hole 1156 penetrates in the longitudinal direction DL. The first core through hole 1156 is located outward in the width direction DW from the first horizontal center line segment Os1. Furthermore, while the cross-sectional shape of the first core through hole 1156 is circular, it is not limited to this and may be polygonal, elliptical, or the like. Note that in FIG. 34 , the first bus bar 100, second bus bar 200, third bus bar 300, first detector 120, second detector 220, third detector 320, and case 70 are not shown to avoid clutter.

The second core 210 includes a second core through hole 2156 instead of the second core recess 2155. The second core through hole 2156 penetrates in the longitudinal direction DL. The second core through hole 2156 is located further outward in the width direction DW than the second horizontal center line segment Os2. Furthermore, while the cross-sectional shape of the second core through hole 2156 is circular, it is not limited to this and may be polygonal, elliptical, or the like.

The third core 310 includes a third core through hole 3156 instead of the third core recess 3155. The third core through hole 3156 penetrates in the longitudinal direction DL. The third core through hole 3156 is located further outward in the width direction DW than the third horizontal center line segment Os3. Furthermore, while the cross-sectional shape of the third core through hole 3156 is circular, it is not limited to this and may be polygonal, elliptical, or the like.

The first core 110, second core 210, and third core 310 are formed to have the same shape. Furthermore, the second core 210 is located between the first core 110 and the third core 310 in the width direction DW. Furthermore, when the second core through hole 2156 on the first core 110 side is projected in the width direction DW, the first core through hole 1156 on the second core 210 side overlaps with the projected second core through hole 2156. Furthermore, when the second core through hole 2156 on the third core 310 side is projected in the width direction DW, the third core through hole 3156 on the second core 210 side overlaps with the projected second core through hole 2156.

The current sensor 5 of the 20th embodiment is configured as described above. This 20th embodiment also achieves the same effects as the 16th and 18th embodiments. Furthermore, in the 20th embodiment, the first core 110, second core 210, and third core 310 are formed to have the same shape.

As described above, this makes it easier to manufacture the first core 110, second core 210, and third core 310 when manufacturing the current sensor 5. This makes it easier to manufacture the current sensor 5.

Twenty-first embodiment
35 to 43, the 21st embodiment differs from the sixth embodiment in the shapes of the first protrusion 731, the second protrusion 732, and the third protrusion 733. Furthermore, the 21st embodiment does not have the first recess 118, the second recess 218, and the third recess 318. Other than this, the 21st embodiment is similar to the sixth embodiment.

As shown in Figure 35, the first protrusion 731 protrudes from the first opposing surface 721 in the thickness direction DT and width direction DW. Furthermore, as shown in Figures 36 and 37, the first protrusion 731 includes a first contact surface 7310 and a first protrusion inclined surface 7311.

The first contact surface 7310 is in contact with the first plate portion 101. The first protrusion inclined surface 7311 is connected to the side of the first contact surface 7310 opposite the first bolt hole 104, in this case, the side of the first extension portion 102. The first protrusion inclined surface 7311 is inclined in a direction such that the size of the space of the first opening 711 increases with increasing distance from the boundary between the first protrusion inclined surface 7311 and the first contact surface 7310. As a result, the first protrusion inclined surface 7311 is formed in a tapered shape.

As shown in Figure 38, the second protrusion 732 protrudes from the second opposing surface 722 in the thickness direction DT and width direction DW. Furthermore, as shown in Figures 39 and 40, the second protrusion 732 includes a second contact surface 7320 and a second protrusion inclined surface 7321.

The second contact surface 7320 is in contact with the second plate portion 201. The second protrusion inclined surface 7321 is connected to the side of the second contact surface 7320 opposite the second bolt hole 204, in this case, the third extension portion 202 side. Furthermore, the second protrusion inclined surface 7321 is inclined in a direction such that the size of the space of the second opening 712 increases with increasing distance from the boundary between the second protrusion inclined surface 7321 and the second contact surface 7320. As a result, the second protrusion inclined surface 7321 is formed in a tapered shape.

As shown in FIG. 41, the third protrusion 733 protrudes from the third opposing surface 723 in the thickness direction DT and width direction DW. Furthermore, as shown in FIGS. 42 and 43, the third protrusion 733 includes a third contact surface 7330 and a third protrusion inclined surface 7331.

The third contact surface 7330 is in contact with the third plate portion 301. The third protrusion inclined surface 7331 is connected to the side of the third contact surface 7330 opposite the third bolt hole 304, in this case, the fifth extension portion 302 side. Furthermore, the third protrusion inclined surface 7331 is inclined in a direction such that the size of the space of the third opening 713 increases with increasing distance from the boundary between the third protrusion inclined surface 7331 and the third contact surface 7330. As a result, the third protrusion inclined surface 7331 is formed in a tapered shape.

As shown in FIG. 36, a plane passing through the substrate 50 and the first lead wire 130 and intersecting perpendicularly to the longitudinal direction DL is defined as a first imaginary plane Si1. As shown in FIG. 39, a plane passing through the substrate 50 and the second lead wire 230 and intersecting perpendicularly to the longitudinal direction DL is defined as a second imaginary plane Si2. As shown in FIG. 42, a plane passing through the substrate 50 and the third lead wire 330 and intersecting perpendicularly to the longitudinal direction DL is defined as a third imaginary plane Si3.

The first protrusion 731 is located on the first imaginary plane Si1, as shown in FIG. 36. The second protrusion 732 is located on the second imaginary plane Si2, as shown in FIG. 39. The third protrusion 733 is located on the third imaginary plane Si3, as shown in FIG. 42.

The current sensor 5 of the 21st embodiment is configured as described above. This 21st embodiment also achieves the same effects as the sixth embodiment. The 21st embodiment also achieves the effects described below.

[13-1] The first protrusion 731 includes a first contact surface 7310 and a first protrusion inclined surface 7311. The first contact surface 7310 is in contact with the first plate portion 101. The first protrusion inclined surface 7311 is connected to the side of the first contact surface 7310 opposite the first bolt hole 104. The first protrusion inclined surface 7311 is inclined in a direction such that the size of the space of the first opening 711 increases with increasing distance from the boundary between the first protrusion inclined surface 7311 and the first contact surface 7310.

As a result, when the first plate portion 101 is inserted into the space of the first opening 711 from the first extension portion 102 side, the first plate portion 101 is guided by the first protrusion inclined surface 7311, making it easier to insert the first plate portion 101. This also reduces wear due to contact between the first plate portion 101 and the first protrusion 731. This prevents wear powder from contacting the first plate portion 101 and the first protrusion 731 from entering the first bolt hole 104. Therefore, when connecting the first plate portion 101 to an external part, such as a part of the inverter, by inserting a bolt into the first bolt hole 104 and a hole provided in the inverter, damage to the first plate portion 101 due to wear powder getting caught in it is prevented.

The second protrusion 732 also includes a second contact surface 7320 and a second protrusion inclined surface 7321. The second contact surface 7320 is in contact with the second plate portion 201. The second protrusion inclined surface 7321 is connected to the second contact surface 7320 on the opposite side from the second bolt hole 204. Furthermore, the second protrusion inclined surface 7321 is inclined in a direction such that the size of the space of the second opening 712 increases with increasing distance from the boundary between the second protrusion inclined surface 7321 and the second contact surface 7320.

As a result, when the second plate portion 201 is inserted into the space of the second opening 712 from the third extension portion 202 side, the second plate portion 201 is guided by the second protrusion inclined surface 7321, making it easier to insert the second plate portion 201. This also reduces wear due to contact between the second plate portion 201 and the second protrusion 732. This prevents wear powder from contacting the second plate portion 201 and the second protrusion 732 from entering the second bolt hole 204. Therefore, when connecting the second plate portion 201 to an external part, such as a part of the inverter, by inserting a bolt into the second bolt hole 204 and a hole provided in the inverter, damage to the second plate portion 201 due to wear powder getting caught in it is prevented.

The third protrusion 733 also includes a third contact surface 7330 and a third protrusion inclined surface 7331. The third contact surface 7330 is in contact with the third plate portion 301. The third protrusion inclined surface 7331 is connected to the side of the third contact surface 7330 opposite the third bolt hole 304. Furthermore, the third protrusion inclined surface 7331 is inclined in a direction such that the size of the space of the third opening 713 increases with increasing distance from the boundary between the third protrusion inclined surface 7331 and the third contact surface 7330.

As a result, when the third plate portion 301 is inserted into the space of the third opening 713 from the fifth extension portion 302 side, the third plate portion 301 is guided by the third protrusion inclined surface 7331, making it easier to insert the third plate portion 301. This also reduces wear due to contact between the third plate portion 301 and the third protrusion 733. This prevents wear powder from contacting the third plate portion 301 and the third protrusion 733 from entering the third bolt hole 304. Therefore, when connecting the third plate portion 301 to an external part, such as a part of the inverter, by inserting a bolt into the third bolt hole 304 and a hole provided in the inverter, damage to the third plate portion 301 due to wear powder getting caught in it is prevented.

[13-2] The first protrusion 731 is located on the first imaginary plane Si1. As a result, the cross-sectional area when cut through the substrate 50, first lead wire 130, and case 70 in a direction perpendicular to the longitudinal direction DL is larger than when the first protrusion 731 is not located on the first imaginary plane Si1. As a result, the section modulus and rigidity of the substrate 50, first lead wire 130, and case 70 are higher than when the first protrusion 731 is not located on the first imaginary plane Si1. Furthermore, when the first plate portion 101 is displaced when connecting the first plate portion 101 to an external device such as part of the inverter, the stress applied to the substrate 50 and first lead wire 130 is reduced. This reduces deformation and damage to the substrate 50 and first lead wire 130.

The second protrusion 732 is located on the second imaginary plane Si2. This increases the cross-sectional area when cut through the substrate 50, the second lead wire 230, and the case 70 in a direction perpendicular to the longitudinal direction DL, compared to when the second protrusion 732 is not located on the second imaginary plane Si2. This increases the section modulus and rigidity of the substrate 50, the second lead wire 230, and the case 70 compared to when the second protrusion 732 is not located on the second imaginary plane Si2. Furthermore, when the second plate portion 201 is displaced when connecting the second plate portion 201 to an external device, such as part of the inverter, the stress acting on the substrate 50 and the second lead wire 230 is reduced. This reduces deformation and damage to the substrate 50 and the second lead wire 230.

Furthermore, the third protrusion 733 is located on the third imaginary plane Si3. As a result, the cross-sectional area when cut through the substrate 50, the third lead wire 330, and the case 70 in a direction perpendicular to the longitudinal direction DL is larger than when the third protrusion 733 is not located on the third imaginary plane Si3. As a result, the section modulus and rigidity of the substrate 50, the third lead wire 330, and the case 70 are higher than when the third protrusion 733 is not located on the third imaginary plane Si3. In addition, when the third plate portion 301 is displaced when connecting the third plate portion 301 to an external device such as part of the inverter, the stress applied to the substrate 50 and the third lead wire 330 is reduced. This reduces deformation and damage to the substrate 50 and the third lead wire 330.

Twenty-second embodiment
44 to 46, the 22nd embodiment differs from the 21st embodiment in the shapes of the first protrusion 731, the second protrusion 732, and the third protrusion 733. Other than this, the 22nd embodiment is similar to the 21st embodiment.

As shown in FIG. 44, the first protrusion 731 protrudes from the first opposing surface 721 in the thickness direction DT and the width direction DW. Furthermore, the first protrusion 731 does not include the first protrusion inclined surface 7311, but includes a first contact surface 7310. The first contact surface 7310 is in contact with the first plate portion 101. The first contact surface 7310 is formed in a convex shape that is convex toward the first plate portion 101, for example, a hemispherical shape. Therefore, the first contact surface 7310 and the first plate portion 101 are in point contact. While the first contact surface 7310 is formed in a hemispherical shape, it is not limited to this and may also be formed in the shape of a circular arc cylindrical side surface, a prolate spheroid, an elliptical arc cylindrical side surface, or the like.

As shown in FIG. 45, the second protrusion 732 protrudes from the second opposing surface 722 in the thickness direction DT and the width direction DW. Furthermore, the second protrusion 732 does not include the second protrusion inclined surface 7321, but includes a second contact surface 7320. The second contact surface 7320 is in contact with the second plate portion 201. The second contact surface 7320 is formed in a convex shape that is convex toward the second plate portion 201, for example, a hemispherical shape. Therefore, the second contact surface 7320 and the second plate portion 201 are in point contact. While the second contact surface 7320 is formed in a hemispherical shape, it is not limited to this and may also be formed in the shape of a circular arc cylindrical side surface, a prolate spheroid, an elliptical arc cylindrical side surface, or the like.

As shown in FIG. 46 , the third protrusion 733 protrudes from the third opposing surface 723 in the thickness direction DT and the width direction DW. Furthermore, the third protrusion 733 does not include the third protrusion inclined surface 7331, but includes a third contact surface 7330. The third contact surface 7330 is in contact with the third plate portion 301. The third contact surface 7330 is formed in a convex shape that is convex toward the third plate portion 301, for example, a hemispherical shape. Therefore, the third contact surface 7330 and the third plate portion 301 are in point contact. While the third contact surface 7330 is formed in a hemispherical shape, it is not limited to this, and may also be formed in the shape of a circular arc cylindrical side surface, a prolate spheroid, an elliptical arc cylindrical side surface, or the like.

The current sensor 5 of the 22nd embodiment is configured as described above. This 22nd embodiment also achieves the same effects as the 21st embodiment.

Twenty-third embodiment
47 to 49, the 23rd embodiment differs from the 21st embodiment in the shapes of the first protrusion 731, the second protrusion 732, and the third protrusion 733. Other than this, the 23rd embodiment is similar to the 21st embodiment.

As shown in FIG. 47, instead of being formed at a position that passes through the center of the first plate portion 101 in the thickness direction DT and the width direction DW, the first protrusion 731 is formed at a position away from the center of the first plate portion 101. Furthermore, the first protrusion 731 protruding in the thickness direction DT is located outward from the first bolt hole 104 in the width direction DW. Therefore, the first protrusion 731 protruding in the thickness direction DT passes through the first bolt hole 104 but does not pass through a plane perpendicular to the width direction DW. Therefore, the first protrusion 731 protruding in the thickness direction DT is more likely to separate from the first bolt hole 104.

As shown in FIG. 48, instead of being formed at a position that passes through the center of the second plate portion 201 in the thickness direction DT and the width direction DW, the second protrusion 732 is formed at a position away from the center of the second plate portion 201. Furthermore, the second protrusion 732 protruding in the thickness direction DT is located outward from the second bolt hole 204 in the width direction DW. Therefore, the second protrusion 732 protruding in the thickness direction DT passes through the second bolt hole 204 but does not pass through a plane perpendicular to the width direction DW. Therefore, the second protrusion 732 protruding in the thickness direction DT is more likely to separate from the second bolt hole 204.

As shown in FIG. 49 , instead of being formed at a position that passes through the center of the third plate portion 301 in the thickness direction DT and the width direction DW, the third protrusion 733 is formed at a position away from the center of the third plate portion 301. Furthermore, the third protrusion 733 protruding in the thickness direction DT is located outward from the third bolt hole 304 in the width direction DW. Therefore, the third protrusion 733 protruding in the thickness direction DT passes through the third bolt hole 304 but does not pass through a plane perpendicular to the width direction DW. Therefore, the third protrusion 733 protruding in the thickness direction DT is more likely to separate from the third bolt hole 304.

The current sensor 5 of the 23rd embodiment is configured as described above. This 23rd embodiment also achieves the same effects as the 21st embodiment.

Twenty-fourth embodiment
50 to 52, the 24th embodiment differs from the 21st embodiment in the shapes of the first protrusion 731, the second protrusion 732, and the third protrusion 733. Other than this, the 24th embodiment is similar to the 21st embodiment.

As shown in FIG. 50 , the first protrusion 731 protruding in the thickness direction DT is formed at a position that passes through the center of the first plate portion 101 in both the thickness direction DT and the width direction DW, but is instead formed at a position away from the center of the first plate portion 101. Furthermore, the first protrusion 731 protruding in the thickness direction DT is positioned further outward than the first bolt hole 104 in the width direction DW. Therefore, the first protrusion 731 protruding in the thickness direction DT passes through the first bolt hole 104 but does not pass through a plane perpendicular to the width direction DW, making it easier for it to separate from the first bolt hole 104.

As shown in FIG. 51 , the second protrusion 732 protruding in the thickness direction DT is formed at a position that passes through the center of the second plate portion 201 in both the thickness direction DT and the width direction DW, but is instead formed at a position away from the center of the second plate portion 201. Furthermore, the second protrusion 732 protruding in the thickness direction DT is positioned outward from the second bolt hole 204 in the width direction DW. Therefore, the second protrusion 732 protruding in the thickness direction DT passes through the second bolt hole 204 but does not pass through a plane perpendicular to the width direction DW, making it easier for it to separate from the second bolt hole 204.

As shown in FIG. 52, the third protrusion 733 protruding in the thickness direction DT is formed at a position that passes through the center of the third plate portion 301 in both the thickness direction DT and the width direction DW, but is instead formed at a position away from the center of the third plate portion 301. Furthermore, the third protrusion 733 protruding in the thickness direction DT is positioned further outward than the third bolt hole 304 in the width direction DW. Therefore, the third protrusion 733 protruding in the thickness direction DT passes through the third bolt hole 304 but does not pass through a plane perpendicular to the width direction DW, making it easier for it to separate from the third bolt hole 304.

The current sensor 5 of the 24th embodiment is configured as described above. This 24th embodiment also achieves the same effects as the 21st embodiment.

Twenty-fifth embodiment
53 to 55, the 25th embodiment differs from the 21st embodiment in the shapes of the first protrusion 731, the second protrusion 732, and the third protrusion 733. Other than this, the 25th embodiment is similar to the 21st embodiment.

The first protrusion 731, instead of being located on the first imaginary plane Si1, is located on the opposite side of the first bolt hole 104 from the first imaginary plane Si1, i.e., on the first extension 102 side, as shown in FIG. 53. The second protrusion 732, instead of being located on the second imaginary plane Si2, is located on the opposite side of the second bolt hole 204 from the second imaginary plane Si2, i.e., on the third extension 202 side, as shown in FIG. 54. The third protrusion 733, instead of being located on the third imaginary plane Si3, is located on the opposite side of the third bolt hole 304 from the third imaginary plane Si3, i.e., on the fifth extension 302 side, as shown in FIG. 55.

The current sensor 5 of the 25th embodiment is configured as described above. This 25th embodiment also achieves the same effects as the 21st embodiment. The 25th embodiment also achieves the effects described below.

[14] The first protrusion 731 is located on the opposite side of the first imaginary plane Si1 from the first bolt hole 104, i.e., on the first extension 102 side.

This allows the first protrusion 731 to more easily separate from the first bolt hole 104. Therefore, when connecting the first plate portion 101 to an external part, such as a part of the inverter, and assuming a constant displacement of the first plate portion 101, the rotation angle of the first plate portion 101 is smaller than when the first protrusion 731 is positioned closer to the first bolt hole 104 than the first imaginary plane Si1. Therefore, when connecting the first plate portion 101 to an external part, such as a part of the inverter, the rotational force acting on the first plate portion 101 is reduced when the first plate portion 101 is displaced. Therefore, when connecting the first plate portion 101 to an external part, such as a part of the inverter, the rotational force and stress acting on the case 70, the circuit board 50, and the first lead wire 130 are reduced when the first plate portion 101 is displaced. This reduces deformation and damage to the circuit board 50 and the first lead wire 130.

Furthermore, the second protrusion 732 is located on the opposite side of the second bolt hole 204 from the second imaginary plane Si2, i.e., on the third extension 202 side.

This allows the second protrusion 732 to more easily separate from the second bolt hole 204. Therefore, when connecting the second plate portion 201 to an external part such as a part of the inverter, assuming a constant displacement of the second plate portion 201, the rotation angle of the second plate portion 201 is smaller than when the second protrusion 732 is positioned closer to the second bolt hole 204 than the second imaginary plane Si2. Therefore, when connecting the second plate portion 201 to an external part such as a part of the inverter, the rotational force acting on the second plate portion 201 when the second plate portion 201 is displaced is reduced. Therefore, when connecting the second plate portion 201 to an external part such as a part of the inverter, the rotational force and stress acting on the case 70, the circuit board 50, and the second lead wire 230 when the second plate portion 201 is displaced is reduced. This reduces deformation and damage to the circuit board 50 and the second lead wire 230.

Furthermore, the third protrusion 733 is located on the opposite side of the third imaginary plane Si3 from the third bolt hole 304, i.e., on the fifth extension 302 side.

This makes it easier for the third protrusion 733 to separate from the third bolt hole 304. Therefore, when connecting the third plate portion 301 to an external part such as a part of the inverter, assuming a constant displacement of the third plate portion 301, the rotation angle of the third plate portion 301 is smaller than when the third protrusion 733 is positioned closer to the third bolt hole 304 than the third imaginary plane Si3. Therefore, when connecting the third plate portion 301 to an external part such as a part of the inverter, the rotational force acting on the third plate portion 301 when the third plate portion 301 is displaced is reduced. Therefore, when connecting the third plate portion 301 to an external part such as a part of the inverter, the rotational force and stress acting on the case 70, the circuit board 50, and the third lead wire 330 when the third plate portion 301 is displaced is reduced. This reduces deformation and damage to the circuit board 50 and the third lead wire 330.

Twenty-sixth embodiment
56 to 58, the twenty-sixth embodiment differs from the sixth embodiment in the shapes of the first core 110, the second core 210, the third core 310, the first bus bar 100, the second bus bar 200, and the third bus bar 300. Furthermore, the twenty-sixth embodiment does not have the first recess 118, the second recess 218, and the third recess 318. Other than these, the twenty-sixth embodiment is the same as the sixth embodiment.

Here, as shown in FIG. 56, the minimum distance from the first core end face 115 to the second core end face 116 in the width direction DW is defined as the first distance Gap1. The maximum distance from the first plate portion 101 to the first gap forming portion 111 in the thickness direction DT is defined as the first clearance distance Clr1_top. The value obtained by dividing the first clearance distance Clr1_top by the first distance Gap1 is defined as the first ratio Clr1/Gap1. Also, as shown in FIG. 57, the minimum distance from the third core end face 215 to the fourth core end face 216 in the width direction DW is defined as the second distance Gap2. The maximum distance from the second plate portion 201 to the second gap forming portion 211 in the thickness direction DT is defined as the second clearance distance Clr2_top. The value obtained by dividing the second clearance distance Clr2_top by the second distance Gap2 is the second ratio Clr2/Gap2. Furthermore, as shown in FIG. 58, the minimum distance from the fifth core end face 315 to the sixth core end face 316 in the width direction DW is the third distance Gap3. The maximum distance from the third plate portion 301 to the third gap forming portion 311 in the thickness direction DT is the third clearance distance Clr3_top. The value obtained by dividing the third clearance distance Clr3_top by the third distance Gap3 is the third ratio Clr3/Gap3.

The first distance Gap1 is, for example, 5.0 to 10.0 mm. The first clearance distance Clr1_top is, for example, 2.0 to 6.0 mm. The first ratio Clr1/Gap1 is, for example, 0.20 or greater and 1.00 or less. The second distance Gap2 is, for example, 5.0 to 10.0 mm. The second clearance distance Clr2_top is, for example, 2.0 to 6.0 mm. The second ratio Clr2/Gap2 is, for example, 0.20 or greater and 1.00 or less. The third distance Gap3 is, for example, 5.0 to 10.0 mm. The third clearance distance Clr3_top is, for example, 2.0 to 6.0 mm. Furthermore, the third ratio Clr2/Gap3 is set to be equal to or greater than 0.20 and equal to or less than 1.00.

The current sensor 5 of the 26th embodiment is configured as described above. This 26th embodiment also provides the same advantages as the 6th embodiment. The 26th embodiment also provides the following advantages.

[15] Now, suppose that an AC current with a frequency of 1 Hz to several kHz and an amplitude of 0 to 2000 A flows through the first bus bar 100. Also, suppose that a DC current with the same amplitude as this AC current flows through the first bus bar 100. Furthermore, let the amplitude of this AC current be Ia. Also, let the value of the DC current with the same amplitude as this AC current be Id. The value obtained by dividing Ia by Id is the amplitude ratio Ia/Id. Also, let Ia and Id be detected by the first detection unit 120.

Furthermore, assume that the value of the first distance Gap1 is fixed and the first ratio Clr1/Gap1 is less than 0.20. In this case, the first clearance distance Clr1_top is relatively short, so the first plate portion 101 and the first gap forming portion 111 are relatively close to each other. This brings the first plate portion 101 and the first gap 117 relatively close to each other, making it easier for the magnetic field leaking from the first gap 117 to penetrate into the first plate portion 101. As a result, the magnetic field leaking from the first gap 117 penetrates into the first plate portion 101, causing the magnetic field to change over time due to changes in the frequency of the inverter's AC current. This makes it easier for an induced electromotive force to be generated in the opposite direction to the current flowing from the inverter to the first plate portion 101. The magnetic field generated by the current flowing through the first plate portion 101 due to this induced electromotive force easily changes the magnetic field acting on the first gap 117. Therefore, errors in the current detected by the current sensor 5 are likely to occur. Furthermore, as the frequency of the inverter's AC current increases, the skin effect causes the current flowing on the surface of the first plate portion 101 due to the induced electromotive force to increase, making the magnetic field applied to the first gap 117 more likely to change. This can easily lead to errors in the current detected by the current sensor 5.

In contrast, in the 26th embodiment, the first ratio Clr1/Gap1 is set to 0.20 or greater.

As a result, the first clearance distance Clr1_top is longer than when the value of the first distance Gap1 is fixed and the first ratio Clr1/Gap1 is less than 0.20. Therefore, the first plate portion 101 and the first gap forming portion 111 are farther apart than when the value of the first distance Gap1 is fixed and the first ratio Clr1/Gap1 is less than 0.20. Therefore, compared to when the value of the first distance Gap1 is fixed and the first ratio Clr1/Gap1 is less than 0.20, the first plate portion 101 and the first gap 117 are farther apart, which reduces the magnetic field lines that penetrate from the first gap 117 into the first plate portion 101. This reduces the generation of induced electromotive force in the direction opposite to the direction of the current flowing through the first plate portion 101. This reduces the likelihood of errors in the current detected by the current sensor 5, improving the frequency characteristics of the current sensor 5.

For this reason, as shown in FIG. 59, the amplitude ratio Ia/Id when the first ratio Clr1/Gap1 is 0.20 or greater is closer to 100% than the amplitude ratio Ia/Id when the first ratio Clr1/Gap1 is less than 0.20, and is less than the first tolerance value. Furthermore, it is more preferable that the first ratio Clr1/Gap1 be 0.30 or greater. Setting the first ratio Clr1/Gap1 to 0.30 or greater brings the amplitude ratio Ia/Id closer to 100% compared to when the first ratio Clr1/Gap1 is 0.20 or greater but less than 0.30. Therefore, setting the first ratio Clr1/Gap1 to 0.30 or greater brings the error in the current detected by the current sensor 5 closer to zero compared to when the first ratio Clr1/Gap1 is 0.20 or greater but less than 0.30. The first and second tolerance values are values related to the allowable error of the current sensor 5. The first tolerance value is, for example, 100.03%. The second tolerance value is, for example, 100.01%.

Furthermore, assume that the first ratio Clr1/Gap1 is greater than 1.00, i.e., Clr1/Gap1 > 1. In this case, the first clearance distance Clr1_top is greater than the first distance Gap1. As a result, the size of the first core 110 in the thickness direction DT is larger than when the first ratio Clr1/Gap1 is 1.00 or less. Therefore, the size of the current sensor 5 is larger than when the first ratio Clr1/Gap1 is 1.00 or less.

For this reason, in the 26th embodiment, the first ratio Clr1/Gap1 is set to 1.00 or less.

As a result, the size of the first core 110 in the thickness direction DT is smaller than when the first ratio Clr1/Gap1 is greater than 1.00. Therefore, the size of the current sensor 5 is smaller than when the first ratio Clr1/Gap1 is greater than 1.00. Therefore, the size of the current sensor 5 is prevented from becoming larger.

In addition, in the 26th embodiment, the second ratio Clr2/Gap2 is greater than or equal to 0.20 and less than or equal to 1.00.

As a result, as with the above, errors in the current detected by the current sensor 5 are less likely to occur compared to when the value of the second distance Gap2 is fixed and the second ratio Clr2/Gap2 is less than 0.20, thereby improving the frequency characteristics of the current sensor 5. Furthermore, compared to when the second ratio Clr2/Gap2 is greater than 1.00, the size of the current sensor 5 is prevented from becoming larger.

Furthermore, in the 26th embodiment, the third ratio Clr3/Gap3 is equal to or greater than 0.20 and equal to or less than 1.00.

As a result, as with the above, errors in the current detected by the current sensor 5 are less likely to occur compared to when the value of the third distance Gap3 is fixed and the third ratio Clr3/Gap3 is less than 0.20, thereby improving the frequency characteristics of the current sensor 5. Furthermore, compared to when the third ratio Clr3/Gap3 is greater than 1.00, the size of the current sensor 5 is prevented from becoming larger.

Twenty-seventh embodiment
As shown in Figures 60 to 62, the 27th embodiment has the same configuration as the 12th embodiment. The 27th embodiment also has the following effects. Note that in Figures 60 to 62, the case 70 and other components are omitted from the illustration to avoid complication.

[16] The first protrusion 1151 and the second protrusion 1152 protrude in the thickness direction DT from the outer surface of the first gap forming portion 111 facing outward in the thickness direction DT. Therefore, the first protrusion 1151 and the second protrusion 1152 protrude in the thickness direction DT from the surface of the first gap forming portion 111 opposite the first plate portion 101.

Here, magnetic field lines passing through the first gap forming portion 111 are more likely to pass through the first protrusion 1151 and the second protrusion 1152 than to exit the first core 110. Furthermore, as described above, the first protrusion 1151 and the second protrusion 1152 protrude in the thickness direction DT from the outer surface of the first gap forming portion 111 facing outward in the thickness direction DT. Therefore, the first protrusion 1151 and the second protrusion 1152 are farther away from the first plate portion 101 than if they protruded toward the first plate portion 101 from the inner surface of the first gap forming portion 111 facing inward in the thickness direction DT. Therefore, magnetic field lines passing through the first protrusion 1151 and the second protrusion 1152 are less likely to pass through the first plate portion 101. This suppresses magnetic field lines from penetrating the first plate portion 101 from the first gap 117. This suppresses the generation of induced electromotive force in the direction opposite to the direction of the current flowing through the first plate portion 101. This reduces the likelihood of errors in the current detected by the current sensor 5, improving the frequency characteristics of the current sensor 5.

Furthermore, the third protrusion 2151 and the fourth protrusion 2152 protrude in the thickness direction DT from the outer surface of the second gap forming portion 211 facing outward in the thickness direction DT. Therefore, the third protrusion 2151 and the fourth protrusion 2152 protrude in the thickness direction DT from the surface of the second gap forming portion 211 opposite the second plate portion 201.

Furthermore, magnetic field lines passing through the second gap forming portion 211 are more likely to pass through the third protrusion 2151 and the fourth protrusion 2152 than to exit the second core 210. As described above, the third protrusion 2151 and the fourth protrusion 2152 protrude in the thickness direction DT from the outer surface of the second gap forming portion 211 facing outward in the thickness direction DT. Therefore, the third protrusion 2151 and the fourth protrusion 2152 are farther away from the second plate portion 201 than if they protruded toward the second plate portion 201 from the inner surface of the second gap forming portion 211 facing inward in the thickness direction DT. Therefore, magnetic field lines passing through the third protrusion 2151 and the fourth protrusion 2152 are less likely to pass through the second plate portion 201. This suppresses magnetic field lines from penetrating the second plate portion 201 from the second gap 217. This suppresses the generation of induced electromotive force in the direction opposite to the direction of the current flowing through the second plate portion 201. This reduces the likelihood of errors in the current detected by the current sensor 5, improving the frequency characteristics of the current sensor 5.

Furthermore, the fifth protrusion 3151 and the sixth protrusion 3152 protrude in the thickness direction DT from the outer surface of the third gap forming portion 311 facing outward in the thickness direction DT. Therefore, the fifth protrusion 3151 and the sixth protrusion 3152 protrude in the thickness direction DT from the surface of the third gap forming portion 311 opposite the third plate portion 301.

Furthermore, here, magnetic field lines passing through the third gap forming portion 311 are more likely to pass through the fifth protrusion 3151 and the sixth protrusion 3152 than to exit the third core 310. Furthermore, as described above, the fifth protrusion 3151 and the sixth protrusion 3152 protrude in the thickness direction DT from the outer surface of the third gap forming portion 311 facing outward in the thickness direction DT. Therefore, the fifth protrusion 3151 and the sixth protrusion 3152 are farther away from the third plate portion 301 than if they protruded toward the third plate portion 301 from the inner surface of the third gap forming portion 311 facing inward in the thickness direction DT. Therefore, magnetic field lines passing through the fifth protrusion 3151 and the sixth protrusion 3152 are less likely to pass through the third plate portion 301. This suppresses magnetic field lines from penetrating the third plate portion 301 from the third gap 317. This suppresses the generation of induced electromotive force in the direction opposite to the direction of the current flowing through the third plate portion 301. This reduces the likelihood of errors in the current detected by the current sensor 5, improving the frequency characteristics of the current sensor 5.

Twenty-eighth embodiment
63 to 68, the 28th embodiment differs from the 24th embodiment in the shapes of the first bus bar 100, the second bus bar 200, and the third bus bar 300. The shapes of the first protrusion 731, the second protrusion 732, and the third protrusion 733 also differ from the 24th embodiment. Other than these, the 28th embodiment is the same as the 24th embodiment.

As shown in Figures 63 and 64, the first bus bar 100 has a first plate portion 101, a first extension portion 102, a second extension portion 103, and a first bus bar protrusion portion 105.

The first bus bar protrusion 105 protrudes from the surface of the first bus bar 100 facing the first opening 711 toward the first opening 711. Specifically, the first bus bar protrusion 105 protrudes in the width direction DW from the first side surface 106 of the first plate portion 101. The first side surface 106 is a surface of the first plate portion 101 that is perpendicular to the width direction DW and corresponds to a surface of the first plate portion 101 that intersects with the width direction DW. While the first bus bar protrusion 105 is formed in a quadrangular prism shape here, this is not limiting. The first bus bar protrusion 105 may also be formed in a polygonal prism shape, a cylindrical shape, a hemispherical shape, etc.

The first protrusion 731 protruding in the width direction DW is in contact with the first bus bar protrusion 105 in the width direction DW. The first protrusion 731 protruding in the thickness direction DT is in contact with the first bus bar protrusion 105 in the thickness direction DT. The Young's modulus of the first protrusion 731 is smaller than the Young's modulus of the first bus bar protrusion 105. This makes the first protrusion 731 more easily deformable than the first bus bar protrusion 105. The Young's modulus of the first protrusion 731 is estimated, for example, from the Young's modulus of the material of the case 70. The Young's modulus of the first bus bar protrusion 105 is estimated, for example, from the Young's modulus of the material of the first bus bar 100.

As shown in Figures 65 and 66, the second bus bar 200 has a second plate portion 201, a third extension portion 202, a fourth extension portion 203, and a second bus bar protrusion portion 205.

The second bus bar protrusion 205 protrudes from the surface of the second bus bar 200 facing the second opening 712 toward the second opening 712. Specifically, the second bus bar protrusion 205 protrudes in the width direction DW from the second side surface 206 of the second plate portion 201. The second side surface 206 is a surface of the second plate portion 201 that is perpendicular to the width direction DW and corresponds to a surface of the second plate portion 201 that intersects with the width direction DW. While the second bus bar protrusion 205 is formed in a quadrangular prism shape here, this is not limiting. The second bus bar protrusion 205 may also be formed in a polygonal prism shape, a cylindrical shape, a hemispherical shape, etc.

The second protrusion 732 protruding in the width direction DW is in contact with the second bus bar protrusion 205 in the width direction DW. The second protrusion 732 protruding in the thickness direction DT is in contact with the second bus bar protrusion 205 in the thickness direction DT. The Young's modulus of the second protrusion 732 is smaller than the Young's modulus of the second bus bar protrusion 205. This makes the second protrusion 732 more easily deformable than the second bus bar protrusion 205. The Young's modulus of the second protrusion 732 is estimated, for example, from the Young's modulus of the material of the case 70. The Young's modulus of the second bus bar protrusion 205 is estimated, for example, from the Young's modulus of the material of the second bus bar 200.

As shown in Figures 67 and 68, the third bus bar 300 has a third plate portion 301, a fifth extension portion 302, a sixth extension portion 303, and a third bus bar protrusion portion 305.

The third bus bar protrusion 305 protrudes from the surface of the third bus bar 300 facing the third opening 713 toward the third opening 713. Specifically, the third bus bar protrusion 305 protrudes in the width direction DW from the third side surface 306 of the third plate portion 301. The third side surface 306 is a surface of the third plate portion 301 that is perpendicular to the width direction DW and corresponds to a surface of the third plate portion 301 that intersects with the width direction DW. While the third bus bar protrusion 305 is formed in a quadrangular prism shape here, this is not limiting. The third bus bar protrusion 305 may also be formed in a polygonal prism, cylindrical, or hemispherical shape.

The third protrusion 733 protruding in the width direction DW is in contact with the third bus bar protrusion 305 in the width direction DW. The third protrusion 733 protruding in the thickness direction DT is in contact with the third bus bar protrusion 305 in the thickness direction DT. The Young's modulus of the third protrusion 733 is smaller than the Young's modulus of the third bus bar protrusion 305. This makes the third protrusion 733 more easily deformable than the third bus bar protrusion 305. The Young's modulus of the third protrusion 733 is estimated, for example, from the Young's modulus of the material of the case 70. The Young's modulus of the third bus bar protrusion 305 is estimated, for example, from the Young's modulus of the material of the third bus bar 300.

The current sensor 5 of the 28th embodiment is configured as described above. This 28th embodiment also achieves the same effects as the 24th embodiment. The 28th embodiment also achieves the effects described below.

[17-1] The first bus bar 100 has a first bus bar protrusion 105. The first bus bar protrusion 105 protrudes from the first side surface 106 in the width direction DW, thereby contacting the first protrusion 731 in the width direction DW. The second bus bar 200 has a second bus bar protrusion 205. The second bus bar protrusion 205 protrudes from the second side surface 206 in the width direction DW, thereby contacting the second protrusion 732 in the width direction DW. The third bus bar 300 has a third bus bar protrusion 305. The third bus bar protrusion 305 protrudes from the third side surface 306 in the width direction DW, thereby contacting the third protrusion 733 in the width direction DW.

When current flows through the first bus bar 100, the second bus bar 200, and the third bus bar 300, the first bus bar 100, the second bus bar 200, and the third bus bar 300 generate heat. Therefore, in the 28th embodiment, a first space 741 is formed by the first protrusion 731 and the first bus bar protrusion 105. A second space 742 is formed by the second protrusion 732 and the second bus bar protrusion 205. A third space 743 is formed by the third protrusion 733 and the third bus bar protrusion 305. The size of the first space 741 when the first bus bar protrusion 105 and the first protrusion 731 are in contact in the width direction DW is larger than the size of the first space 741 when the first side surface 106 and the first protrusion 731 are in contact in the width direction DW. Furthermore, the size of the second space 742 when the second bus bar protrusion 205 and the second protrusion 732 are in contact in the width direction DW is larger than the size of the second space 742 when the second side surface 206 and the second protrusion 732 are in contact in the width direction DW. Also, the size of the third space 743 when the third bus bar protrusion 305 and the third protrusion 733 are in contact in the width direction DW is larger than the size of the third space 743 when the third side surface 306 and the third protrusion 733 are in contact in the width direction DW.

This makes it difficult for heat generated by the first bus bar 100, second bus bar 200, and third bus bar 300 to be transferred to the case 70. As a result, heat is less likely to be transferred from the case 70 to the first detection unit 120, second detection unit 220, and third detection unit 320. This reduces changes in the characteristics and failures of the elements of the first detection unit 120, second detection unit 220, and third detection unit 320.

Furthermore, since the first bus bar protrusion 105 is in contact with the first protrusion 731 in the width direction DW, it becomes easier to position the case 70 and the first bus bar 100 in the width direction DW. Furthermore, since the second bus bar protrusion 205 is in contact with the second protrusion 732 in the width direction DW, it becomes easier to position the case 70 and the second bus bar 200 in the width direction DW. Furthermore, since the third bus bar protrusion 305 is in contact with the third protrusion 733 in the width direction DW, it becomes easier to position the case 70 and the third bus bar 300 in the width direction DW.

[17-2] The first protrusion 731 protrudes from the first opposing surface 721 in the thickness direction DT. The first protrusion 731 protruding in the thickness direction DT is in contact with the first bus bar protrusion 105 in the thickness direction DT.

This makes it easier to position the case 70 and the first bus bar 100 in the thickness direction DT.

The second protrusion 732 protrudes from the second opposing surface 722 in the thickness direction DT. The second protrusion 732 protruding in the thickness direction DT is in contact with the second bus bar protrusion 205 in the thickness direction DT.

This makes it easier to position the case 70 and the second bus bar 200 in the thickness direction DT.

Furthermore, the third protrusion 733 protrudes from the third opposing surface 723 in the thickness direction DT. The third protrusion 733 protruding in the thickness direction DT is in contact with the third bus bar protrusion 305 in the thickness direction DT.

This makes it easier to position the case 70 and the third bus bar 300 in the thickness direction DT.

[17-3] The Young's modulus of the first protrusion 731 is smaller than the Young's modulus of the first bus bar protrusion 105.

As a result, the first protrusion 731 is more easily deformed than the first busbar protrusion 105. Therefore, the first protrusion 731 is more likely to absorb the stress energy that is generated when the first plate portion 101 is displaced when connecting the first plate portion 101 to an external part, such as part of the inverter. This reduces damage to the main body of the case 70.

The Young's modulus of the second protrusion 732 is smaller than the Young's modulus of the second bus bar protrusion 205.

This makes the second protrusion 732 more susceptible to deformation than the second busbar protrusion 205. Therefore, the second protrusion 732 is more likely to absorb the stress energy that is generated when the second plate portion 201 is displaced when connecting the second plate portion 201 to an external part, such as part of the inverter. This reduces damage to the main body of the case 70.

The Young's modulus of the third protrusion 733 is smaller than the Young's modulus of the third bus bar protrusion 305.

As a result, the third protrusion 733 is more easily deformed than the third busbar protrusion 305. Therefore, the third protrusion 733 is more likely to absorb the stress energy that is generated when the third plate portion 301 is displaced when connecting the third plate portion 301 to an external part, such as part of the inverter. This reduces damage to the main body of the case 70.

Twenty-ninth embodiment
In the twenty-ninth embodiment, as shown in Figures 69 to 71, the first opening 711 does not include a first protrusion 731. The second opening 712 does not include a second protrusion 732. The third opening 713 does not include a third protrusion 733. In addition, the shapes of the first bus bar protrusion 105, the second bus bar protrusion 205, and the third bus bar protrusion 305 differ from those of the twenty-eighth embodiment. Other than these, the twenty-ninth embodiment is the same as the twenty-eighth embodiment.

As shown in FIG. 69, the first bus bar protrusion 105 protrudes from the first side surface 106 in the width direction DW, thereby contacting the first opposing surface 721. The first bus bar protrusion 105 also protrudes from the first plate surface S1 in the thickness direction, thereby contacting the first opposing surface 721. Note that here, the first plate surface S1 is a surface of the first plate portion 101 that is perpendicular to the thickness direction DT and corresponds to a surface of the first plate portion 101 that intersects with the thickness direction DT.

As shown in FIG. 70, the second bus bar protrusion 205 protrudes from the second side surface 206 in the width direction DW, thereby contacting the second opposing surface 722. Furthermore, the second bus bar protrusion 205 protrudes from the second plate surface S2 in the thickness direction, thereby contacting the second opposing surface 722. Note that, in this case, the second plate surface S2 is a surface of the second plate portion 201 that is perpendicular to the thickness direction DT and corresponds to a surface of the second plate portion 201 that intersects with the thickness direction DT.

As shown in FIG. 71, the third busbar protrusion 305 protrudes from the third side surface 306 in the width direction DW, thereby contacting the third opposing surface 723. Furthermore, the third busbar protrusion 305 protrudes from the third plate surface S3 in the thickness direction, thereby contacting the third opposing surface 723. Note that, in this case, the third plate surface S3 is a surface of the third plate portion 301 that is perpendicular to the thickness direction DT and corresponds to a surface of the third plate portion 301 that intersects with the thickness direction DT.

The current sensor 5 of the 29th embodiment is configured as described above. This 29th embodiment also provides the same advantages as the 28th embodiment. The 29th embodiment also provides the following advantages.

[18] The first bus bar protrusion 105 protrudes from the surface of the first bus bar 100 facing the first opening 711 toward the first opening 711, thereby making contact with the first opposing surface 721 of the first opening 711. The second bus bar protrusion 205 protrudes from the surface of the second bus bar 200 facing the second opening 712 toward the second opening 712, thereby making contact with the second opposing surface 722 of the second opening 712. The third bus bar protrusion 305 protrudes from the surface of the third bus bar 300 facing the third opening 713 toward the third opening 713, thereby making contact with the third opposing surface 723 of the third opening 713.

As a result, similar to the above, the first space 741, second space 742, and third space 743 are formed, which makes it difficult for heat generated by the first bus bar 100, second bus bar 200, and third bus bar 300 to be transferred to the case 70. Also, similar to the above, it becomes easier to position the case 70 relative to the first bus bar 100, second bus bar 200, and third bus bar 300.

Thirty Embodiment
72 to 74, the 30th embodiment differs from the 29th embodiment in the shapes of the first opposing surface 721, the second opposing surface 722, and the third opposing surface 723. Other than this, the 30th embodiment is similar to the 29th embodiment.

In the 30th embodiment, the first opposing surface 721 is inclined with respect to the longitudinal direction DL, thereby forming a tapered shape. The second opposing surface 722 is also inclined with respect to the longitudinal direction DL, thereby forming a tapered shape. The third opposing surface 723 is also inclined with respect to the longitudinal direction DL, thereby forming a tapered shape.

The current sensor 5 of the 30th embodiment is configured as described above. This 30th embodiment also achieves the same effects as the 29th embodiment.

Thirty-first embodiment
75 to 77, the 31st embodiment differs from the 28th embodiment in the shapes of the first protrusion 731, the second protrusion 732, the third protrusion 733, the first bus bar protrusion 105, the second bus bar protrusion 205, and the third bus bar protrusion 305. Other than this, the 31st embodiment is the same as the 28th embodiment.

The first protrusions 731 protruding in the width direction DW are aligned in the longitudinal direction DL. Furthermore, the first bus bar protrusions 105 are sandwiched between adjacent first protrusions 731. This allows the first bus bar protrusions 105 and the first protrusions 731 protruding in the width direction DW to be in contact with each other in the longitudinal direction DL.

The second protrusions 732 protruding in the width direction DW are aligned in the longitudinal direction DL. Furthermore, the second bus bar protrusions 205 are sandwiched between adjacent second protrusions 732. Therefore, the second bus bar protrusions 205 and the second protrusions 732 protruding in the width direction DW are in contact with each other in the longitudinal direction DL.

The third protrusions 733 protruding in the width direction DW are aligned in the longitudinal direction DL. Furthermore, the third bus bar protrusions 305 are sandwiched between adjacent third protrusions 733. This allows the third bus bar protrusions 305 and the third protrusions 733 protruding in the width direction DW to be in contact with each other in the longitudinal direction DL.

The current sensor 5 of the 31st embodiment is configured as described above. This 31st embodiment also achieves the same effects as the 28th embodiment.

(Other embodiments)
The present disclosure is not limited to the above-described embodiments, and appropriate modifications can be made to the above-described embodiments. Furthermore, it goes without saying that the elements constituting the embodiments in the above-described embodiments are not necessarily essential unless they are specifically stated as essential or are considered to be clearly essential in principle.

In the above embodiment, the current sensor 5 detects the three-phase AC current of the inverter. However, the number of inverter phases detected by the current sensor 5 is not limited to three, and may be one or more.

In the above embodiment, the first core 110, the second core 210, and the third core 310 are formed by bending a plate-shaped soft magnetic material into a C-shape. However, the first core 110, the second core 210, and the third core 310 are not limited to being formed by bending a plate-shaped soft magnetic material into a C-shape. For example, the first core 110, the second core 210, and the third core 310 may be formed by wire-cutting a plate-shaped soft magnetic material. The first core 110, the second core 210, and the third core 310 may also be formed by winding a sheet-shaped soft magnetic material. In this case, an adhesive material is used to prevent peeling between the soft magnetic materials. Furthermore, the first core 110, the second core 210, and the third core 310 may be formed by overlapping and stacking sheet-shaped soft magnetic materials. In this case, multiple soft magnetic materials are formed into sheets by press working, and the sheet-shaped soft magnetic materials are stacked by dowel caulking.

Also, suppose the first core 110, second core 210, and third core 310 are laminated using plate-shaped permalloy. In this case, the hysteresis characteristics of the first core 110, second core 210, and third core 310 are improved compared to when the first core 110, second core 210, and third core 310 are laminated using plate-shaped directional electromagnetic steel sheets. Furthermore, suppose the first core 110, second core 210, and third core 310 are formed using plate-shaped directional electromagnetic steel sheets. In this case, material costs are reduced compared to when the first core 110, second core 210, and third core 310 are formed using permalloy, and therefore the cost of the current sensor 5 can be reduced.

In the above embodiment, the first opening 711, the second opening 712, and the third opening 713 are formed in a rectangular tubular shape. However, the first opening 711, the second opening 712, and the third opening 713 are not limited to being formed in a rectangular tubular shape, and may be formed in a polygonal tubular shape, a cylindrical shape, or the like.

In the above embodiment, the first protrusion 731, the second protrusion 732, and the third protrusion 733 are formed in a rectangular prism shape. However, the first protrusion 731, the second protrusion 732, and the third protrusion 733 are not limited to being formed in a rectangular prism shape, and may be formed in a polygonal prism shape, a cylindrical shape, or a hemisphere shape.

In the above embodiment, the first core end face 115, the second core end face 116, the third core end face 215, the fourth core end face 216, the fifth core end face 315, and the sixth core end face 316 are formed in a planar shape. In contrast, the first core end face 115, the second core end face 116, the third core end face 215, the fourth core end face 216, the fifth core end face 315, and the sixth core end face 316 are not limited to being formed in a planar shape. The first core end face 115, the second core end face 116, the third core end face 215, the fourth core end face 216, the fifth core end face 315, and the sixth core end face 316 may be formed in a spherical or curved shape.

In the first and third embodiments described above, the number of first recesses 118, second recesses 218, and third recesses 318 is one. In contrast, the number of first recesses 118, second recesses 218, and third recesses 318 is not limited to one. The number of first recesses 118, second recesses 218, and third recesses 318 may be two or more.

In the second embodiment described above, the number of first through holes 119, second through holes 219, and third through holes 319 is one. In contrast, the number of first through holes 119, second through holes 219, and third through holes 319 is not limited to one. The number of first through holes 119, second through holes 219, and third through holes 319 may be two or more.

In the above embodiments, the current sensor 5 is used in an inverter, but this is not limited to this and may also be used in, for example, a BMS. BMS stands for Battery Management System.

In each of the above embodiments, the first bus bar 100, second bus bar 200, and third bus bar 300 have a width greater than their thickness, but this is not limited to this, and the thickness may be greater than their width.

The above embodiments may be combined as appropriate.

(Features of the present disclosure)
(assignment)
According to the inventors' research, there is a need to expand the range of current magnitudes that can be detected by current sensors. However, in the case of a current sensor such as that described in Patent Document 1, when the magnitude of the current detected by the current sensor increases, magnetic saturation occurs in the core, making it difficult to expand the range of current magnitudes that can be detected by the current sensor.
The present disclosure aims to provide a current sensor that suppresses magnetic saturation.

[First viewpoint]
A current sensor,
A bus bar (100, 200, 300) formed in a plate shape;
a core hole (114, 214, 314) into which the bus bar is inserted, a first end face (115, 215, 315) facing the width direction (DW) of the bus bar, a second end face (116, 216, 316) facing the first end face in the width direction, and a gap forming portion (111, 211, 31) including a gap (117, 217, 317) formed by the first end face and the second end face and communicating with the core hole and the outside; a core (110, 120, 130) having a core horizontal portion (112, 212, 312, 1121, 2122, 3123) connected to the gap forming portion and extending in the thickness direction (DT) of the bus bar, and a core bottom portion (113, 213, 313, 1131, 2132, 3133) connected to the core horizontal portion and extending in the width direction, and forming the core hole together with the gap forming portion and the core horizontal portion;
a detection unit (120, 220, 320) disposed in the gap and configured to detect the strength of a magnetic field generated in the gap by a current flowing through the bus bar;
Equipped with
A current sensor in which the magnetic permeability of the side portion of the core is greater than the magnetic permeability of the bottom portion of the core.
[Second viewpoint]
A current sensor,
A bus bar (100, 200, 300) formed in a plate shape;
a core (110, 120, 130) having a core hole (114, 214, 314) into which the bus bar is inserted, a first end face (115, 215, 315) facing the width direction (DW) of the bus bar, a second end face (116, 216, 316) facing the first end face in the width direction, and a gap forming portion (111, 211, 311) including a gap (117, 217, 317) formed by the first end face and the second end face and communicating the core hole with the outside, core horizontal portions (1121, 2122, 3123) connected to the gap forming portion and extending in the thickness direction (DT) of the bus bar, and a core bottom portion (1131, 2132, 3133) connected to the core horizontal portion and extending in the width direction and forming the core hole together with the gap forming portion and the core horizontal portion;
a detection unit (120, 220, 320) disposed in the gap and configured to detect the strength of a magnetic field generated in the gap by a current flowing through the bus bar;
Equipped with
A current sensor in which the magnetic permeability of the side portion of the core is smaller than the magnetic permeability of the bottom portion of the core.
[Third viewpoint]
A current sensor,
A bus bar (100, 200, 300) formed in a plate shape;
a core (110, 120, 130) having a core hole (114, 214, 314) into which the bus bar is inserted, a first end face (115, 215, 315) facing the width direction (DW) of the bus bar, a second end face (116, 216, 316) facing the first end face in the width direction, and a gap forming portion (111, 211, 311) including a gap (117, 217, 317) formed by the first end face and the second end face and communicating the core hole with the outside, core horizontal portions (1121, 2122, 3123) connected to the gap forming portion and extending in the thickness direction (DT) of the bus bar, and a core bottom portion (1131, 2132, 3133) connected to the core horizontal portion and extending in the width direction and forming the core hole together with the gap forming portion and the core horizontal portion;
a detection unit (120, 220, 320) disposed in the gap and configured to detect the strength of a magnetic field generated in the gap by a current flowing through the bus bar;
Equipped with
the length of the core bottom portion in the thickness direction is equal to the length of the core lateral portion in the width direction,
A current sensor in which the magnetic permeability of the side portion of the core is different from the magnetic permeability of the bottom portion of the core.
[Fourth viewpoint]
The gap forming portion is
a first surface (151, 251, 351) connected to an edge of the first end surface and extending from the edge of the first end surface in a direction away from the gap;
a second surface (152, 252, 352) connected to the edge of the second end surface and extending from the edge of the second end surface in a direction away from the gap;
The current sensor according to any one of the first to third aspects, comprising:
[Fifth Aspect]
A current sensor according to any one of the first to fourth aspects, wherein lateral inner corners (C1_in_top, C2_in_top, C3_in_top), which are inner corners at the boundary between the gap forming portion and the core lateral portion, are rounded.
[Sixth Aspect]
A current sensor described in any one of the first to fourth aspects, wherein the lateral inner corners (C1_in_top, C2_in_top, C3_in_top), which are inner corners at the boundary between the gap forming portion and the core lateral portion, are inclined surfaces that are inclined with respect to the width direction and the thickness direction.
[Seventh Viewpoint]
A current sensor according to any one of the first to sixth aspects, wherein the bottom inner corners (C1_in_btm, C2_in_btm, C3_in_btm), which are inner corners at the boundary between the core side portion and the core bottom portion, are rounded.
[Eighth Viewpoint]
A current sensor described in any one of the first to sixth aspects, wherein the bottom inner corners (C1_in_btm, C2_in_btm, C3_in_btm), which are inner corners at the boundary between the core side portion and the core bottom portion, are inclined surfaces that are inclined with respect to the width direction and the thickness direction.
[Ninth Viewpoint]
the core includes a core recess (1155, 2155, 3155);
A current sensor described in any one of the first to eighth aspects, wherein the core recess is recessed from the outer edge of the core on the outside in the width direction and the thickness direction toward the inside of the core in a cross section of the core when the core is cut in a direction perpendicular to the longitudinal direction (DL) of the bus bar.
[Tenth Aspect]
In a cross section of the core taken in a direction perpendicular to the longitudinal direction, a line segment passing through the center of the gap forming portion in the thickness direction and extending in the width direction is defined as a gap center line segment (Og1, Og2, Og3),
In a cross section of the core when the core is cut in a direction perpendicular to the longitudinal direction, a line segment passing through the center of the core lateral portion in the width direction and extending in the thickness direction is defined as a lateral center line segment (Os1, Os2, Os3),
In a cross section of the core taken in a direction perpendicular to the longitudinal direction, a line segment passing through the center of the core bottom in the thickness direction and extending in the width direction is defined as a bottom center line segment (Ob1, Ob2, Ob3),
the gap center line segment is a line segment connecting the lateral center line segments arranged in the width direction,
the horizontal center line segment is a line segment connecting the gap center line segment and the bottom center line segment,
The bottom center line segment is a line segment connecting the horizontal center line segments arranged in the width direction,
The current sensor according to a ninth aspect, wherein the core recess is located in an area (Rc1, Rc2, Rc3) outside the gap center line segment, the lateral center line segment, and the bottom center line segment.
[Eleventh Aspect]
the core includes a core through-hole (1156, 2156, 3156) therein;
The current sensor according to any one of the first to eighth aspects, wherein the core through hole penetrates the bus bar in a longitudinal direction (DL) of the bus bar.
[Twelfth Aspect]
In a cross section of the core taken in a direction perpendicular to the longitudinal direction, a line segment passing through the center of the gap forming portion in the thickness direction and extending in the width direction is defined as a gap center line segment (Og1, Og2, Og3),
In a cross section of the core when the core is cut in a direction perpendicular to the longitudinal direction, a line segment passing through the center of the core lateral portion in the width direction and extending in the thickness direction is defined as a lateral center line segment (Os1, Os2, Os3),
In a cross section of the core taken in a direction perpendicular to the longitudinal direction, a line segment passing through the center of the core bottom in the thickness direction and extending in the width direction is defined as a bottom center line segment (Ob1, Ob2, Ob3),
the gap center line segment is a line segment connecting the lateral center line segments arranged in the width direction,
the horizontal center line segment is a line segment connecting the gap center line segment and the bottom center line segment,
The bottom center line segment is a line segment connecting the horizontal center line segments arranged in the width direction,
The current sensor according to an eleventh aspect, wherein the core through-hole is located in an area (Rc1, Rc2, Rc3) outside the gap center line segment, the lateral center line segment, and the bottom center line segment.

(assignment)
In the current sensor described in Patent Document 1, a magnetic field leaking from the core gap penetrates the bus bar, and changes in the magnetic field over time occur due to changes in the frequency of the AC current, generating an induced electromotive force in the direction opposite to the direction of the current flowing through the bus bar. The magnetic field generated by the current flowing through the bus bar due to this induced electromotive force changes the magnetic field applied to the core gap. This causes an error in the current detected by the current sensor, resulting in a deterioration in the frequency characteristics of the current sensor.
An object of the present disclosure is to provide a current sensor with improved frequency characteristics.

[First viewpoint]
A current sensor,
A bus bar (100, 200, 300) formed in a plate shape;
a core hole (114, 214, 314) into which the bus bar is inserted, a first end face (115, 215, 315) facing the width direction (DW) of the bus bar, a second end face (116, 216, 316) facing the first end face in the width direction, and a gap forming portion (111, 211, 31) including a gap (117, 217, 317) formed by the first end face and the second end face and communicating with the core hole and the outside; a core (110, 120, 130) having a core horizontal portion (112, 212, 312, 1121, 2122, 3123) connected to the gap forming portion and extending in the thickness direction (DT) of the bus bar, and a core bottom portion (113, 213, 313, 1131, 2132, 3133) connected to the core horizontal portion and extending in the width direction, and forming the core hole together with the gap forming portion and the core horizontal portion;
a detection unit (120, 220, 320) disposed in the gap and configured to detect the strength of a magnetic field generated in the gap by a current flowing through the bus bar;
Equipped with
The bus bar is
a first projection portion (Ps1, Ps3, Ps5) that is a portion of the bus bar that overlaps with the projected first end surface when the first end surface is projected onto the bus bar in a thickness direction (DT) of the bus bar;
second projection portions (Ps2, Ps4, Ps6) that are portions of the bus bar that overlap with the projected second end surfaces when the second end surfaces are projected onto the bus bar in the thickness direction;
an area (R1, R2, R3) between the first projection unit and the second projection unit;
a recess (118, 218, 318) recessed from the region in the thickness direction;
A current sensor having
[Second viewpoint]
A current sensor,
A bus bar (100, 200, 300) formed in a plate shape;
a core hole (114, 214, 314) into which the bus bar is inserted, a first end face (115, 215, 315) facing the width direction (DW) of the bus bar, a second end face (116, 216, 316) facing the first end face in the width direction, and a gap forming portion (111, 211, 31) including a gap (117, 217, 317) formed by the first end face and the second end face and communicating with the core hole and the outside; a core (110, 120, 130) having a core horizontal portion (112, 212, 312, 1121, 2122, 3123) connected to the gap forming portion and extending in the thickness direction (DT) of the bus bar, and a core bottom portion (113, 213, 313, 1131, 2132, 3133) connected to the core horizontal portion and extending in the width direction, and forming the core hole together with the gap forming portion and the core horizontal portion;
a detection unit (120, 220, 320) disposed in the gap and configured to detect the strength of a magnetic field generated in the gap by a current flowing through the bus bar;
Equipped with
The bus bar is
a first projection portion (Ps1, Ps3, Ps5) that is a portion of the bus bar that overlaps with the projected first end surface when the first end surface is projected onto the bus bar in a thickness direction (DT) of the bus bar;
second projection portions (Ps2, Ps4, Ps6) that are portions of the bus bar that overlap with the projected second end surfaces when the second end surfaces are projected onto the bus bar in the thickness direction;
an area (R1, R2, R3) between the first projection unit and the second projection unit;
a through hole (119, 219, 319) penetrating from the region in the thickness direction;
A current sensor having

(assignment)
In the current sensor described in Patent Document 1, a magnetic field leaking from the core gap penetrates the bus bar, and changes in the magnetic field over time occur due to changes in the frequency of the AC current, generating an induced electromotive force in the direction opposite to the direction of the current flowing through the bus bar. The magnetic field generated by the current flowing through the bus bar due to this induced electromotive force changes the magnetic field applied to the core gap. This causes an error in the current detected by the current sensor, resulting in a deterioration in the frequency characteristics of the current sensor.
An object of the present disclosure is to provide a current sensor with improved frequency characteristics.

[First viewpoint]
A current sensor,
A bus bar (100, 200, 300) formed in a plate shape;
a core hole (114, 214, 314) into which the bus bar is inserted, a first end face (115, 215, 315) facing the width direction (DW) of the bus bar, a second end face (116, 216, 316) facing the first end face in the width direction, and a gap forming portion (111, 211, 31) including a gap (117, 217, 317) formed by the first end face and the second end face and communicating with the core hole and the outside; a core (110, 120, 130) having a core horizontal portion (112, 212, 312, 1121, 2122, 3123) connected to the gap forming portion and extending in the thickness direction (DT) of the bus bar, and a core bottom portion (113, 213, 313, 1131, 2132, 3133) connected to the core horizontal portion and extending in the width direction, and forming the core hole together with the gap forming portion and the core horizontal portion;
a detection unit (120, 220, 320) disposed in the gap and configured to detect the strength of a magnetic field generated in the gap by a current flowing through the bus bar;
Equipped with
A current sensor in which the value (Clr1/Gap1, Clr2/Gap2, Clr3/Gap3) obtained by dividing the distance (Clr1_top, Clr2_top, Clr2_top) from the bus bar to the gap forming portion in the thickness direction by the distance (Gap1, Gap2, Gap3) from the first end face to the second end face in the width direction is 0.20 or more and 1.00 or less.

(assignment)
When a current flows through a bus bar, the bus bar generates heat. Therefore, in a current sensor such as that described in Patent Document 1, the heat generated by the bus bar is transferred to the sensor chip serving as a detection unit via a case that houses the bus bar. This can cause changes in the characteristics of the sensor chip and lead to failure.
An object of the present disclosure is to provide a current sensor that suppresses heat transfer to a detection section.

[First viewpoint]
A current sensor,
A bus bar (100, 200, 300) formed in a plate shape;
a core hole (114, 214, 314) into which the bus bar is inserted, a first end face (115, 215, 315) facing the width direction (DW) of the bus bar, a second end face (116, 216, 316) facing the first end face in the width direction, and a gap forming portion (111, 211, 31) including a gap (117, 217, 317) formed by the first end face and the second end face and communicating with the core hole and the outside; a core (110, 120, 130) having a core horizontal portion (112, 212, 312, 1121, 2122, 3123) connected to the gap forming portion and extending in the thickness direction (DT) of the bus bar, and a core bottom portion (113, 213, 313, 1131, 2132, 3133) connected to the core horizontal portion and extending in the width direction, and forming the core hole together with the gap forming portion and the core horizontal portion;
a detection unit (120, 220, 320) disposed in the gap and configured to detect the strength of a magnetic field generated in the gap by a current flowing through the bus bar;
a case (70) containing the core;
Equipped with
the case has openings (711, 712, 713) that are inserted into the core holes and into which the bus bars are inserted,
The opening is
An opposing surface (721, 722, 723) facing the bus bar;
a protruding portion (731, 732, 733) that protrudes from the opposing surface toward the bus bar and is in contact with the bus bar;
Including,
A current sensor in which spaces (741, 742, 743) are formed between the opposing surfaces and the bus bars.
[Second viewpoint]
A current sensor,
A bus bar (100, 200, 300) formed in a plate shape;
a core hole (114, 214, 314) into which the bus bar is inserted, a first end face (115, 215, 315) facing the width direction (DW) of the bus bar, a second end face (116, 216, 316) facing the first end face in the width direction, and a gap forming portion (111, 211, 31) including a gap (117, 217, 317) formed by the first end face and the second end face and communicating with the core hole and the outside; a core (110, 120, 130) having a core horizontal portion (112, 212, 312, 1121, 2122, 3123) connected to the gap forming portion and extending in the thickness direction (DT) of the bus bar, and a core bottom portion (113, 213, 313, 1131, 2132, 3133) connected to the core horizontal portion and extending in the width direction, and forming the core hole together with the gap forming portion and the core horizontal portion;
a detection unit (120, 220, 320) disposed in the gap and configured to detect the strength of a magnetic field generated in the gap by a current flowing through the bus bar;
a case (70) containing the core;
Equipped with
the case has openings (711, 712, 713) that are inserted into the core holes and into which the bus bars are inserted,
the bus bar has a protruding portion (105, 205, 305) that protrudes from a surface facing the opening toward the opening and is in contact with the opening,
A current sensor in which spaces (741, 742, 743) are formed between the opening and the bus bar portion.

(assignment)
In the current sensor described in Patent Document 1, stress is applied to the core during manufacturing of the current sensor, which may cause a change in the crystal structure of the core, resulting in a deterioration in the magnetic properties of the core, such as the BH characteristics.
An object of the present disclosure is to provide a current sensor that suppresses deterioration of magnetic properties.

[First viewpoint]
A current sensor,
A bus bar (100, 200, 300) formed in a plate shape;
a core hole (114, 214, 314) into which the bus bar is inserted, a first end face (115, 215, 315) facing the width direction (DW) of the bus bar, a second end face (116, 216, 316) facing the first end face in the width direction, and a gap forming portion (111, 211, 31) including a gap (117, 217, 317) formed by the first end face and the second end face and communicating with the core hole and the outside; a core (110, 120, 130) having a core horizontal portion (112, 212, 312, 1121, 2122, 3123) connected to the gap forming portion and extending in the thickness direction (DT) of the bus bar, and a core bottom portion (113, 213, 313, 1131, 2132, 3133) connected to the core horizontal portion and extending in the width direction, and forming the core hole together with the gap forming portion and the core horizontal portion;
a detection unit (120, 220, 320) disposed in the gap and configured to detect the strength of a magnetic field generated in the gap by a current flowing through the bus bar;
Equipped with
the core includes a core recess (1155, 2155, 3155);
The core recess is a current sensor that is recessed from the outer edge of the core on the outside in the width direction and the thickness direction toward the inside of the core in a cross section of the core when the core is cut in a direction perpendicular to the longitudinal direction (DL) of the bus bar.
[Second viewpoint]
A current sensor,
A bus bar (100, 200, 300) formed in a plate shape;
a core hole (114, 214, 314) into which the bus bar is inserted, a first end face (115, 215, 315) facing the width direction (DW) of the bus bar, a second end face (116, 216, 316) facing the first end face in the width direction, and a gap forming portion (111, 211, 31) including a gap (117, 217, 317) formed by the first end face and the second end face and communicating with the core hole and the outside; a core (110, 120, 130) having a core horizontal portion (112, 212, 312, 1121, 2122, 3123) connected to the gap forming portion and extending in the thickness direction (DT) of the bus bar, and a core bottom portion (113, 213, 313, 1131, 2132, 3133) connected to the core horizontal portion and extending in the width direction, and forming the core hole together with the gap forming portion and the core horizontal portion;
a detection unit (120, 220, 320) disposed in the gap and configured to detect the strength of a magnetic field generated in the gap by a current flowing through the bus bar;
Equipped with
the core includes a core through-hole (1156, 2156, 3156) therein;
The core through hole penetrates the bus bar in the longitudinal direction (DL) of the current sensor.

(assignment)
According to the inventors' research, there is a need to expand the range of current magnitudes that can be detected by current sensors. However, in the case of a current sensor such as that described in Patent Document 1, when the magnitude of the current detected by the current sensor increases, magnetic saturation occurs in the core, making it difficult to expand the range of current magnitudes that can be detected by the current sensor.
The present disclosure aims to provide a current sensor that suppresses magnetic saturation.

[First viewpoint]
A current sensor,
A bus bar (100, 200, 300) formed in a plate shape;
a core hole (114, 214, 314) into which the bus bar is inserted, a first end face (115, 215, 315) facing the width direction (DW) of the bus bar, a second end face (116, 216, 316) facing the first end face in the width direction, and a gap forming portion (111, 211, 31) including a gap (117, 217, 317) formed by the first end face and the second end face and communicating with the core hole and the outside; a core (110, 120, 130) having a core horizontal portion (112, 212, 312, 1121, 2122, 3123) connected to the gap forming portion and extending in the thickness direction (DT) of the bus bar, and a core bottom portion (113, 213, 313, 1131, 2132, 3133) connected to the core horizontal portion and extending in the width direction, and forming the core hole together with the gap forming portion and the core horizontal portion;
a detection unit (120, 220, 320) disposed in the gap and configured to detect the strength of a magnetic field generated in the gap by a current flowing through the bus bar;
Equipped with
The core has protrusions (1151, 1152, 2151, 2152, 3151, 3152) protruding from the gap forming portion in the thickness direction.

100, 200, 300 Busbar 110, 120, 130 Core 111, 211, 311 Gap forming portion 114, 214, 314 Core hole 117, 217, 317 Gap 118, 218, 318 Recess 119, 219, 319 Through hole 120, 220, 320 Detection portion R1, R2, R3 Region

Claims (5)

A current sensor,
A bus bar (100, 200, 300) formed in a plate shape;
a core hole (114, 214, 314) into which the bus bar is inserted, a first end face (115, 215, 315) facing the width direction (DW) of the bus bar, a second end face (116, 216, 316) facing the first end face in the width direction, and a gap forming portion (111, 211, 31) including a gap (117, 217, 317) formed by the first end face and the second end face and communicating with the core hole and the outside; a core (110, 120, 130) having a core horizontal portion (112, 212, 312, 1121, 2122, 3123) connected to the gap forming portion and extending in the thickness direction (DT) of the bus bar, and a core bottom portion (113, 213, 313, 1131, 2132, 3133) connected to the core horizontal portion and extending in the width direction, and forming the core hole together with the gap forming portion and the core horizontal portion;
a detection unit (120, 220, 320) disposed in the gap and configured to detect the strength of a magnetic field generated in the gap by a current flowing through the bus bar;
Equipped with
Since the core is formed of a grain-oriented electromagnetic steel sheet, the magnetic permeability of the side portion of the core is smaller than the magnetic permeability of the bottom portion of the core,
The core is laminated,
the gap forming portion, the core side portion, and the core bottom portion are integral with each other,
the core has protrusions (1151, 1152, 2151, 2152, 3151, 3152) that protrude in the thickness direction from an outer surface of the gap forming portion that faces outward in the thickness direction,
The protrusion includes a protrusion surface (1161, 1162, 2161, 2162, 3161, 3162),
the protruding surface faces inward in the width direction and is connected to the first end surface,
If a line passing through the center in the thickness direction of a surface where the protrusion surface and the first end surface are joined and extending in the width direction is defined as a center line (O1, O2, O3),
the detection portion is disposed closer to the core hole than the center line,
The length of the core bottom portion in the thickness direction is shorter than the length of the core lateral portion in the width direction . 2. The current sensor according to claim 1, wherein a value (Clr1/Gap1, Clr2/Gap2, Clr3/Gap3) obtained by dividing a distance (Clr1_top, Clr2_top, Clr3_top) from the bus bar to the gap forming portion in the thickness direction by a distance (Gap1, Gap2, Gap3) from the first end face to the second end face in the width direction is 0.20 or more and 1.00 or less . A current sensor as described in claim 1 or 2, wherein the outer corners (C1_out_top, C2_out_top, C3_out_top) of the gap forming portion in the width direction and the outer corners (C1_out_btm, C2_out_btm, C3_out_btm) of the core bottom in the width direction are rounded. A current sensor as described in claim 1 or 2, wherein the inner corners (C1_in_top, C2_in_top, C3_in_top) at the boundary between the gap forming portion and the core side portion, and the inner corners (C1_in_btm, C2_in_btm, C3_in_btm) at the boundary between the core side portion and the core bottom portion are rounded. The bus bar is a first bus bar (100),
The core hole is a first core hole (114),
The gap is a first gap (117),
The gap forming portion is a first gap forming portion (111),
The core horizontal portion is a first core horizontal portion (112, 1121),
The core bottom is a first core bottom (113, 1131),
The core is a first core (110),
The detection unit is a first detection unit (120),
The protrusions are first protrusions (1151, 1152),
The current sensor
a second bus bar (200) formed in a plate shape;
a second core (120) having a second core hole (214) into which the bus bar is inserted, a third end face (215) facing the width direction, a fourth end face (216) opposing the third end face in the width direction, and a second gap forming portion (211) including a second gap (217) formed by the third end face and the fourth end face and communicating the second core hole with the outside, a second core horizontal portion (212, 2122) connected to the second gap forming portion and extending in the thickness direction, and a second core bottom portion (213, 2132) connected to the second core horizontal portion and extending in the width direction, forming the second core hole together with the second gap forming portion and the second core horizontal portion;
a second detection unit (220) disposed in the second gap and configured to detect the strength of a magnetic field generated in the second gap by a current flowing through the second bus bar;
Equipped with
the second core has second protrusions (2151, 2152) protruding in the thickness direction from an outer surface of the second gap forming portion facing outward in the thickness direction,
The current sensor according to claim 1 , wherein the first core and the second core are aligned in the width direction.