JP7328633B2 - Current sensor and its core hold unit - Google Patents

Description

The present invention relates to a structure for holding cores and bus bars, which are constituent members of a current sensor.

A conventional current sensor consists of a bus bar that forms an energization path, and a core that collects the magnetic flux generated by the current of the bus bar and a U-shaped magnetic material that has a gap in a part of the ring and collects the magnetic flux in the gap. , magneto-sensitive elements that are inserted into the core gap to detect the magnetic flux density, and a case that holds them.

Further, the conventional current sensor has a core hold unit in which the core, the bus bar and the molding resin are integrated by insert molding the core and the bus bar. Insert molding includes a method of directly inserting the core and busbars into a molding die, and a method of integrating the core and busbars with a holding member and inserting the integrated assembly into the molding die. When there are a plurality of cores and bus bars, a method of inserting the assembly using the holding member, which is excellent in work efficiency of inserting into the molding die, is used (see Patent Documents 1 and 2, for example).

JP 2013-242294 A (page 13, FIG. 3) Japanese Patent Application Laid-Open No. 2016-206172 (page 16, FIG. 3)

As described above, a plurality of cores and busbars are pre-assembled by a hold member, and then the conventional hold member is insert-molded. In order to hold the outer peripheral surface formed by It is a structure that holds the board thickness of the bus bar by inserting it into the inner diameter of the core. In this case, the insertion directions of the core and busbar into the hold member are different by 90 degrees, and the core and busbar cannot be inserted into the hold member from the same direction. Is required.

Also, as described above, when insert molding an assembly, the assembly is inserted into the molding die. Since the direction in which the core is inserted into the mold and the direction in which the core is inserted into the hold member differ by 90 degrees, there is a locking structure for the purpose of preventing the core from falling out of the hold member and positional displacement when inserting the assembly into the mold. Required for the hold member.

Further, as described above, the U-shaped core having a gap portion is a laminated core formed by punching a plate-shaped magnetic material with a press die and stacking them, or a laminated core formed by winding a plate-shaped magnetic material around a core to form an annular shape. , a wound core having a gap formed by cutting a part of the ring is generally used. In any core, punching burrs or cut burrs of the magnetic material may remain in the gap. On the other hand, in a current sensor in which a magneto-sensitive element is arranged in the gap of the core, the magnetic flux generated from the busbar is collected in the gap, and detected by the magneto-sensitive element, the relative positions of the magneto-sensitive element and the gap are important. Therefore, the positioning and fixing of the core gap in the case are important when performing insert molding. When positioning the core gap in the insert molding die, a method of positioning the gap is used by inserting the core into a molding die having a convex shape along the width of the core gap. When the core gap portion is inserted into the mold having the convex shape, the core gap portion and the convex shape come into direct contact with each other, so that the press burrs or cut burrs in the core gap portion fall off into the mold and the case mold is removed. There is a possibility that a foreign magnetic material, which is a conductor, is kneaded into the resin. Since a high voltage is applied to the busbars of the current sensor, insulation is provided between the busbars and between the busbar and the core by molding resin, which is an insulator. dielectric breakdown.

The present invention has been made to solve the above-mentioned problems, and the core and bus bar can be inserted into the hold member from the same direction, and the direction of inserting the assembly into the insert molding die can be changed to the hold member. The core and busbar can be inserted without changing the insertion direction, and there is no need for a locking structure to prevent the core from falling out or misalignment when inserting the assembly into the molding die, and the gap between the cores can be inserted into the molding die. It is an object of the present invention to provide a holding member capable of positioning a gap within a mold without direct contact.

The core hold unit used in the current sensor of the present invention comprises a U-shaped core having a gap in a part of an annular shape and a busbar forming a current-carrying path, which are integrally formed by insert molding with molded resin. The core and the bus bar are assembled to the member from the same direction.

According to this invention, the efficiency of assembling the core and the bus bar to the holding member is improved, and the mechanism of the equipment can be simplified when the equipment is used for assembly.

4A and 4B are perspective views of a core hold unit according to Embodiment 1 of the present invention; FIG. 4A and 4B are perspective views of an assembly in which a bus bar is attached to a hold member according to Embodiment 1 of the present invention; FIG. 4(A) and 4(B) are perspective views of an assembly in which a core is assembled after a busbar has been assembled to a hold member according to Embodiment 1 of the present invention. FIG. (A) is a plan view of FIG. 3, and (B) and (C) are cross-sectional views. (A) and (B) are perspective views of a holder according to Embodiment 1 of the present invention. (A) is a plan view of FIG. 5, and (B), (C) and (D) are cross-sectional views. 4 is a perspective view of a core according to Embodiment 1 of the present invention; FIG. 1A is a perspective view of a busbar according to Embodiment 1 of the present invention, and FIGS. 1B and 1C are front views of the busbar. FIG. 1A is a perspective view of a current sensor unit according to Embodiment 1 of the present invention; FIG. (B) is a perspective view showing the positional relationship between the core hold unit and the magneto-sensitive element, (C) is a plan view of the current sensor unit, and (D) is a sectional view.

Embodiment 1
FIG. 1 is a perspective view of core hold unit 100 according to Embodiment 1 of the present invention. In FIG. 1, a core hold unit 100 inserts a plurality of busbars 2 and a plurality of cores 4 into a holder 3 which is a holding member for assembling a plurality of busbars 2 and a plurality of cores 4 before insert molding. It is inserted into a molding die (not shown) and insert-molded with molding resin (case 1) to form an integrated structure.

8A and 8B are a perspective view and a front view of the busbar 2 according to Embodiment 1 of the present invention. The bus bar 2 is made of a copper material or an aluminum material, has a plate-like outer shape with a thickness of 2a, a length of 2b, and a width of 2c, and has a concave portion 2d or a convex portion 2e for positioning.
FIG. 7 is a perspective view of the core 4 according to Embodiment 1 of the present invention. In FIG. 7, the core 4 has a U-shape with a gap portion 4a, and is a laminated core formed by punching a plate-shaped magnetic material with a press die and stacking them, or winding a plate-shaped magnetic material around the core to form an annular shape. After that, a part of the ring is cut to form a gap 4a.
FIG. 5 is a perspective view of holder 3 according to Embodiment 1 of the present invention, and FIG. 6 is a plan view and a sectional view thereof. In FIG. 5, the holder 3 is made of molded resin material and has a core insertion portion 3a into which the core 4 is inserted, a busbar insertion portion 3b into which the busbar 2 is inserted, and a concave portion 3c used for positioning the molding die and for inserting the magneto-sensitive element 5a. . The busbar inserting portion 3b has a groove shape that is equal to or slightly larger than the plate thickness 2a of the busbar 2 . The core insertion portion 3a and the busbar insertion portion 3b are opened so that the core 4 and the busbar 2 are both inserted from the arrow direction k. 6, the core insertion portion 3a has a resin wall 3f along the outer peripheral surface 4c of the core 4, a resin wall 3g along the inner peripheral surface 4b, a resin wall 3h along the side surface 4f, and a resin wall 3i along the bottom surface 4e. 3c has resin walls 3d and 3e.
FIG. 2 is a perspective view of the bus bar 2 inserted into the holder 3 according to Embodiment 1 of the present invention. By inserting the busbar 2 into the busbar insertion portion 3b of the holder 3 in FIG. Further, by combining the recess 2d or the projection 2e provided on the busbar 2 with the holder 3, it is possible to position the busbar 2 on the holder 3 in the direction of the length 2b.
FIG. 3 is a perspective view of an assembly in which the core 4 is assembled after the bus bar 2 has been assembled to the holder 3 according to Embodiment 1 of the present invention, and FIG. 4 is a plan view and a sectional view thereof. By inserting the core 4 into the core insertion portion 3a of the holder 3 in FIG. Directional positioning is possible.
FIG. 9 is a perspective view of current sensor unit 200 according to Embodiment 1 of the present invention. In FIG. 9, the current sensor unit 200 has a signal processing section 5 consisting of a magneto-sensitive element 5a, a connector 5b for inputting/outputting its output signal and control power supply, and a printed circuit board 5c on which these are mounted. The printed circuit board 5c is inserted into the recess 3c of the mold unit 100 and positioned and fixed to the core mold unit 100 with screws 6. As shown in FIG.

In the core holding unit 100 configured as described above, both the insertion of the busbar 2 and the insertion of the core 4 into the holder 3 are performed in the same arrow direction k, and the busbar 2 and the core 4 can be held in the holder without changing the direction of the holder 3 . 3, the efficiency of assembly and the simplification of the assembly mechanism become possible.

Further, by blocking the core 4 with the resin walls 3f, 3g, 3h, and 3i, the busbar 2 and the core 4 are insulated from each other even when a high voltage is applied to the busbar 2. It becomes possible to secure with the holder 3.

In addition, by inserting the assembly into the insert molding die from the arrow direction j (see FIG. 3) that is the same direction as the insertion direction k of the bus bar 2 and the core 4 into the holder 3, the bus bar 2 and the core 4 into the holder 3 From the insertion of the assembly to the insertion of the assembly into the insert molding die, the operation can be performed without changing the direction of the holder 3, and the bus bar 2 and the core 4 can be prevented from falling off from the holder 3 during insertion into the insert molding die.

Also, by inserting the assembly into an insert molding mold having a convex shape along the concave portion 3c of the holder 3, the width of the gap 4a of the core 4 can be adjusted without bringing the gap 4a of the core 4 into direct contact with the insert molding mold. Since the direction and the vertical direction of the gap width can be determined, press burrs or cut burrs in the core gap portion do not drop into the molding die. Therefore, highly reliable insulation can be ensured by preventing magnetic foreign matter, which is a conductor, from being kneaded into the mold resin of the case 1 and causing dielectric breakdown between the busbars and between the busbar and the core.
In the current sensor unit 200 configured as described above, the magnetic flux generated by the current flowing through the busbar 2 and collected in the core gap 4a is detected by the magneto-sensitive element 5a inserted in the concave portion 3c. Output to the outside of the sensor unit 200 . When a high voltage is applied to the busbar 2, a voltage is induced in the core 4 adjacent to the busbar 2 by capacitive coupling, and the voltage of the core 4 is also increased. If the magneto-sensitive element 5a placed in the high-voltage core gap 4a is discharged, the magneto-sensitive element 5a may be damaged. The resin walls 3d and 3e ensure highly reliable insulation between the core 4 and the magneto-sensitive element 5a.

1: Case (mold resin material)
2: Bus bar (copper material or aluminum material)
2a: Thickness of busbar 2b: Length of busbar 2c: Width of busbar 2d: Lengthwise positioning shape of busbar (concave)
2e: Lengthwise positioning shape of bus bar (convex)
3: Holder (mold resin material)
3a: core insertion portion 3b: busbar insertion portion 3c: holding member positioning portion for molding die and magneto-sensitive element placement portion 3d: holding member positioning portion for molding die (core gap width direction)
3e: Hold member positioning portion for molding die (perpendicular to core gap width)
3f: Resin wall 3g of the hold member along the core outer peripheral surface 4c: Resin wall 3h of the hold member along the core gap 4a and the inner peripheral surface 4b: Resin wall 3i of the hold member along the core side surface 4f: Along the core bottom surface 4e Resin wall 4 of hold member: core (magnetic material)
4a: core gap 4b: inner peripheral surface of core 4c: outer peripheral surface of core 4d: top surface of core 4e: bottom surface of core 4f: side surface formed in the thickness direction of core 5: signal processing unit 5a: magneto-sensitive element 5b : Connector 5c: Printed circuit board 6: Screw j: Assembly insertion direction into insert molding die k: Busbar and core insertion direction to holder 100: Core hold unit 200: Current sensor unit

Claims (3)

It is a holding member made of an insulating material to which a U-shaped core having a gap in a part of the ring and formed of a magnetic material and a plate-shaped bus bar extending in a direction orthogonal to the thickness and width can be assembled. A U-shaped core has an inner peripheral surface, an outer peripheral surface, a side surface formed in the thickness direction, and a first concave portion and a first recess formed in a wall shape along a top surface in contact with the inner peripheral surface, the outer peripheral surface, and the side surface, respectively. a core insertion portion having two recesses, and a groove having a U-shaped opening along the thickness of the bus bar between the first and second recesses and on the opening side of the first and second recesses. , the core can be inserted into the hold member from the gap side of the core, and the busbar can be inserted from the same direction as the core. holding material. The holding member has a third recess having an opening shape in a direction opposite to the inserting direction of the core. 2. The holding member according to claim 1, wherein the holding member is formed on a second surface opposite to the first surface and has a side surface between the first and second recesses. The bus bar is inserted into the groove of the holding member, the core is inserted into the first and second recesses, and the magneto-sensitive element is inserted into the third recess. A magnetic flux is generated around the bus bar, the magnetic flux is collected in the core, and the collected magnetic flux interlinks the gap of the core. 3. The hold member according to claim 2, which is used in a current sensor capable of detecting a current flowing through the bus bar by detecting a magnetic flux interlinking the portion.

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