JP7536714B2 - Electric motor - Google Patents

Description

The present invention relates to an electric motor having a stator wound with a coil and a rotor that rotates relative to the stator.

A small, lightweight, flat electric motor is used as the driving source for electric transport vehicles that transport harvested crops, etc., and for welfare equipment such as electric wheelchairs. By operating an operating switch or the like to supply a driving current to the electric motor, the wheels are driven, and the vehicle can move freely. Such a flat electric motor is described, for example, in Patent Document 1.

The electric motor described in Patent Document 1 has a case and a cover, and the housing formed by butting these together contains a flat motor and a hypocycloid reducer inside. A cable with a first connector and a cable with a second connector are connected to the housing, respectively, which supplies a drive current to the flat motor.

JP 2017-073860 A

However, in the electric motor described in the above-mentioned Patent Document 1, the cable with connector is fixed to the connector fixing portion of the cover via a connecting member (nut). Therefore, although the strength of the fixing of the cable with connector to the cover is sufficiently ensured, it is necessary to prepare a nut and then tighten the nut with a specified tightening torque, which complicates the assembly work.

The object of the present invention is to provide an electric motor that can be easily assembled while ensuring sufficient fixing strength of the cable to the housing.

In one aspect of the present invention, an electric motor has a stator around which a coil is wound and a rotor that rotates relative to the stator, the electric motor having a plurality of power feeders that supply power to the coil, a terminal fixed to a longitudinal base end of the power feeders, a sensor board on which a magnetic sensor is provided that detects a rotation state of the rotor, a sensor cable electrically connected to the sensor board and having a plurality of core wires, a housing that holds the plurality of power feeders and the sensor cable, and a drop-out prevention plate that is attached to the housing and prevents the plurality of power feeders and the sensor cable from falling off from the housing, the sensor cable having a covering member that covers the plurality of core wires , the drop-out prevention plate having a first protrusion that protrudes toward the housing in the axial direction of the rotor and a support protrusion that supports a side of the terminal in a radial direction of the drop-out prevention plate, the sensor cable being sandwiched between the first protrusion and the housing, and the covering member being elastically deformed by the first protrusion.

According to the present invention, the anti-dropout plate is provided with a first protrusion that protrudes toward the housing in the axial direction of the rotor, and the sensor cable having a covering member is clamped between the first protrusion and the housing, and the covering member is elastically deformed by the first protrusion. As a result, simply by fixing the anti-dropout plate to the housing, the fixing strength of the sensor cable to the housing can be sufficiently ensured and assembly can be easily performed.

FIG. 2 is a perspective view showing an output rotor side of the electric motor. FIG. 2 is a plan view showing the output rotor side of the electric motor. 3 is a cross-sectional view taken along line AA in FIG. 2. FIG. 2 is an exploded perspective view showing the cover side of the electric motor. FIG. FIG. 4 is an exploded perspective view illustrating the structure inside the cover. FIG. 4 is a plan view illustrating the layout of the power supply line and the sensor cable. FIG. 4 is a perspective view showing the fall-off prevention plate alone. FIG. 4 is a perspective view illustrating the flat female terminal portion inside the cover. FIG. 3 is a partially enlarged cross-sectional view taken along line BB in FIG. 2. FIG. 3 is a partially enlarged cross-sectional view taken along line CC in FIG. 2. 10A is a cross-sectional view of the sensor cable in a natural state, and FIG. 10B is a cross-sectional view of the sensor cable in an elastically deformed state taken along line DD in FIG.

Below, one embodiment of the present invention will be described in detail with reference to the drawings.

1 is a perspective view showing the output rotor side of the motor, FIG. 2 is a plan view showing the output rotor side of the motor, FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2, FIG. 4 is an exploded perspective view showing the cover side of the motor, FIG. 5 is a perspective view showing the cover alone, FIG. 6 is an exploded perspective view explaining the structure inside the cover, FIG. 7 is a plan view explaining the layout of the power supply line and the sensor cable, FIG. 8 is a perspective view showing the fall prevention plate alone, FIG. 9 is a perspective view explaining the flat female terminal part inside the cover, FIG. 10 is a partially enlarged cross-sectional view taken along line B-B in FIG. 2, FIG. 11 is a partially enlarged cross-sectional view taken along line C-C in FIG. 2, FIG. 12(a) is a cross-sectional view of the sensor cable in its natural state, and (b) is a cross-sectional view taken along line D-D in FIG. 10 of the sensor cable in its elastically deformed state.

The electric motor 10 shown in FIG. 1 drives the wheels (not shown) of an electric transport vehicle that transports harvested crops, etc., and is a relatively high-output motor device. The electric motor 10 is supplied with a driving current from a battery or the like by operating an operating switch or the like (not shown), which causes it to rotate in the forward or reverse direction at a predetermined rotation speed.

As shown in Figures 1 to 3, the electric motor 10 is formed in a generally disk-like flat shape, which allows for a small and lightweight motor. The electric motor 10 has a case 20 and a cover 30 that form its outer shell, and the case 20 and the cover 30 are butted against each other and fixed by a total of five fixing screws SC1.

As shown in FIG. 3, a motor housing chamber MS is formed inside the case 20 and the cover 30, and a flat motor 40, which is a brushless motor, is housed inside the motor housing chamber MS. Also housed inside the motor housing chamber MS is a sensor board 50 provided with three Hall sensors HS (see FIG. 6 and FIG. 7) that detect the rotation state of the flat motor 40 (rotor 42). Here, the cover 30 corresponds to the housing in this invention.

As shown in FIG. 3, the case 20 is formed by casting an aluminum material or the like into a stepped, roughly bowl-like shape, and includes a large-diameter cylindrical section 21 and a small-diameter cylindrical section 22. The large-diameter cylindrical section 21 is disposed on the cover 30 side (lower side in the figure) in the axial direction of the case 20, and the small-diameter cylindrical section 22 is disposed on the opposite side to the cover 30 side (upper side in the figure) in the axial direction of the case 20.

A roughly disk-shaped partition wall 23 is integrally provided between the large diameter cylindrical portion 21 and the small diameter cylindrical portion 22 in the axial direction of the case 20. The partition wall 23, together with the large diameter cylindrical portion 21, forms the motor housing chamber MS. The partition wall 23, together with the small diameter cylindrical portion 22, forms the reducer housing chamber RS. In other words, the partition wall 23 separates the motor housing chamber MS from the reducer housing chamber RS.

A through hole 23a through which the rotor shaft 45 passes is provided in the center of the partition wall 23. A first ball bearing B1 that rotatably supports the shaft body 45a of the rotor shaft 45 is mounted on the radial inside of the through hole 23a.

The flat motor 40 housed inside the motor housing MS has a thickness dimension smaller than its diameter dimension, giving it a flat shape. The flat motor 40 is an inner rotor type brushless motor, and includes an annular stator core (stator) 41 made of multiple laminated steel plates, and a rotor 42 that is rotatably mounted radially inside the stator core 41 via a specified air gap. The stator core 41 is fixed to the partition wall 23 by a total of three fixing screws SC2 (see Figure 4), which allows the rotor 42 to rotate relative to the stator core 41.

An insulator 43 made of an insulating material such as plastic is attached to the stator core 41. The insulator 43 covers almost the entire stator core 41, including the multiple teeth (not shown), and coils 44 are wound in concentrated winding on the portions of the insulator 43 that correspond to the teeth. In other words, the coils 44 are wound around each tooth of the stator core 41 via the insulator 43.

The rotor 42 has a main body 42a formed into a roughly bowl shape by pressing a steel plate or the like. A cylindrical permanent magnet 42b is fixed to the radially outer side of the main body 42a. The permanent magnet 42b is magnetized so that north and south poles appear alternately in the circumferential direction of the rotor 42. In addition, a shaft body 45a of the rotor shaft 45 is fixed to the center of rotation on the radially inner side of the main body 42a, and the rotor shaft 45 rotates in conjunction with the rotation of the rotor 42.

The rotor shaft 45 comprises a shaft body 45a, a first shaft portion 45b, and a second shaft portion 45c, and the axis of the first shaft portion 45b is located at a position offset (eccentric) by a predetermined amount from the axis of the shaft body 45a. In contrast, the axis of the second shaft portion 45c coincides with the axis of the shaft body 45a. The shaft body 45a is rotatably supported by the case 20 via the first ball bearing B1, and the rotor 42 is rotatably supported by the case 20 via the rotor shaft 45.

The reduction gear housing chamber RS houses a hypocycloid reduction gear 60, which is a reduction mechanism. The hypocycloid reduction gear 60 reduces the rotation of the flat motor 40 (rotor shaft 45) and outputs it to the outside, and is equipped with an outer gear 61 and an inner gear 62.

The outer gear 61 is formed in an annular shape and is disposed toward the flat motor 40 in the axial direction of the small diameter cylindrical portion 22. The outer radial side of the outer gear 61 is fixed to the inner radial side of the small diameter cylindrical portion 22, and a tooth portion 61a consisting of spur teeth is formed on the inner radial side of the outer gear 61.

The inner gear 62 is disposed radially inside the outer gear 61, and its outer diameter is smaller than the inner diameter of the outer gear 61. A first tooth portion 62a consisting of spur teeth is formed on the radially outer side of the inner gear 62, and the first tooth portion 62a of the inner gear 62 meshes with the tooth portion 61a of the outer gear 61. In other words, the inner gear 62 rolls inside the outer gear 61 without slipping.

The center of rotation of the inner gear 62 is rotatably supported by the first shaft portion 45b of the rotor shaft 45 via a pair of second ball bearings B2. As a result, when the first shaft portion 45b rotates radially inside the outer gear 61, the inner gear 62 rotatably supported by the pair of second ball bearings B2 rotates radially inside the outer gear 61 at a slower speed than the rotor shaft 45.

A second tooth portion 62b consisting of spur teeth is formed radially inside the first tooth portion 62a of the inner gear 62. The second tooth portion 62b is meshed with a tooth portion 63a consisting of spur teeth of the output rotor 63. Specifically, the tooth portion 63a of the output rotor 63 is disposed radially inside the second tooth portion 62b of the inner gear 62, and its outer diameter dimension is smaller than the inner diameter dimension of the second tooth portion 62b of the inner gear 62. As a result, the output rotor 63 rolls radially inside the second tooth portion 62b of the inner gear 62 without slipping, and rotates at a slower speed than the inner gear 62.

The output rotor 63 is rotatably supported at its radially inner side by a third ball bearing B3 provided on the second shaft portion 45c, and at its radially outer side by a fourth ball bearing B4 provided on the cover member 64. This allows the output rotor 63, which is subject to a particularly large load, to rotate smoothly for a long period of time. The wheels (not shown) of the electric transport vehicle are fixed to the output rotor 63. Therefore, the rotation of the flat motor 40, which has been reduced in speed by the hypocycloid reducer 60, is transmitted to the wheels of the electric transport vehicle in a high-torque state.

The cover member 64 closes the reduction gear housing chamber RS of the case 20, and is fixed to the small diameter cylindrical portion 22 of the case 20 by a total of four fixing screws SC3, as shown in Figures 1 and 2.

As shown in FIG. 3, the hypocycloid reducer 60 has a flat shape and is capable of achieving a relatively large reduction ratio (1/90). Therefore, by adopting it in a flat-shaped electric motor 10, it is possible to easily make the electric motor 10 even flatter (thinner). The "reduction ratio (1/90)" mentioned here means that when the rotor shaft 45 rotates at high speed 90 times, the output rotor 63 finally rotates once in a high-torque state.

As shown in Figures 3 to 5, the cover 30 is formed in a roughly bowl shape by injection molding a resin material such as plastic. The cover 30 has a bottom wall portion 31 formed in a disk shape and a cylindrical side wall portion 32 that is integrally provided on the outer periphery of the bottom wall portion 31.

The side wall 32 is provided with a wiring insertion hole 32a that communicates between the inside and outside of the cover 30. The wiring insertion hole 32a is opened in a substantially rectangular shape, and a rubber grommet 33 (see Figures 3, 10, and 11) that is a sealing member is attached to the wiring insertion hole 32a. The three power supply lines 70u, 70v, and 70w and one sensor cable 80 (see Figures 6 and 7) are each inserted into the grommet 33. This prevents rainwater, dust, and the like from entering the inside of the cover 30 through the wiring insertion hole 32a.

Specifically, as shown in Figures 10 and 11, the grommet 33 has three small diameter holes 33a (only one is shown in the figure) and one large diameter hole 33b, and the power supply lines 70u, 70v, and 70w are inserted into the small diameter holes 33a, respectively, and the sensor cable 80 is inserted into the large diameter hole 33b. In other words, the three power supply lines 70u, 70v, and 70w and the one sensor cable 80 are pulled out to the outside of the cover 30 via the wiring insertion hole 32a and the grommet 33. Here, the wiring insertion hole 32a corresponds to the cable pull-out portion in this invention.

A fixing plate 34 (see Figures 1, 3, 10, and 11) is provided on the outside of the side wall 32 at the wiring insertion hole 32a so as to cover the wiring insertion hole 32a. The fixing plate 34 prevents the grommet 33 attached to the wiring insertion hole 32a from falling off, and is fixed to the side wall 32 by a pair of fixing screws SC4.

As shown in Figures 5 and 7, a line segment CT connects the axial center of the rotor shaft 45 (see Figure 4) and the central portion of the wiring insertion hole 32a in the circumferential direction of the side wall portion 32 in the radial direction of the cover 30. Also, with the line segment CT as the boundary, one radial side of the cover 30 (the right side in Figure 5 and the left side in Figure 7) is the first cover portion C1, and the other radial side of the cover 30 (the left side in Figure 5 and the right side in Figure 7) is the second cover portion C2.

As shown in FIG. 5, a total of three terminal holders 35a, 35b, and 35c are provided on the inside of the side wall portion 32 and on the side of the first cover portion C1. Each of these terminal holders 35a, 35b, and 35c is formed in a hollow box shape, and inside each of them are mounted a flat female terminal M1 crimped to the longitudinal base end of the U-phase power supply line 70u, a flat female terminal M2 crimped to the longitudinal base end of the V-phase power supply line 70v, and a flat female terminal M3 crimped to the longitudinal base end of the W-phase power supply line 70w (see FIG. 6, FIG. 7, and FIG. 9).

In addition, rod-shaped engaging protrusions 36a, 36b are provided on the inside of the side wall 32 on the first cover part C1 side and the second cover part C2 side. These engaging protrusions 36a, 36b protrude to a height dimension that exceeds the side wall 32 of the cover 30, and have the function of guiding the attachment of the cover 30 to the case 20 (see FIG. 4). Specifically, when the cover 30 is attached to the case 20, these engaging protrusions 36a, 36b are first inserted into the engaging recesses (not shown) of the case 20.

This allows the cover 30 to be positioned accurately relative to the case 20, while allowing them to be securely attached to each other. By simply attaching the cover 30 to the case 20, the flat male terminals T1, T2, and T3 (see FIG. 4) on the case 20 side are electrically connected to the respective flat female terminals M1, M2, and M3 with high precision. Here, the flat male terminal T1 connected to the flat female terminal M1 (for U phase) is electrically connected to the coil 44 corresponding to the U phase, the flat male terminal T2 connected to the flat female terminal M2 (for V phase) is electrically connected to the coil 44 corresponding to the V phase, and the flat male terminal T3 connected to the flat female terminal M3 (for W phase) is electrically connected to the coil 44 corresponding to the W phase.

By supplying drive current to each of the power supply lines 70u, 70v, and 70w at a predetermined timing, power is supplied to the coils 44 (see FIG. 4) corresponding to the U-phase, V-phase, and W-phase, respectively, and an electromagnetic force is generated in the stator core 41 (see FIG. 4). As a result, the rotor 42 (see FIG. 4) is driven to rotate in the forward or reverse direction at a predetermined rotational speed.

As shown in Figures 6 and 7, the longitudinal base ends of the U-phase power feeder 70u, the V-phase power feeder 70v, and the W-phase power feeder 70w are housed inside the cover 30. The longitudinal base end of the sensor cable 80 and the sensor board 50 are also housed inside the cover 30. Furthermore, a fall prevention plate 90 that prevents the power feeders 70u, 70v, and 70w and the sensor cable 80 from falling off the cover 30 is housed inside the cover 30.

As shown in FIG. 5, the bottom wall 31 of the cover 30 on the first cover part C1 side is provided with a first retaining groove 31b for retaining the U-phase power supply line 70u, a second retaining groove 31c for retaining the V-phase power supply line 70v, and a third retaining groove 31d for retaining the W-phase power supply line 70w. This allows the power supply lines 70u, 70v, and 70w to be easily routed inside the cover 30 without interfering with or crossing each other.

Furthermore, a fourth holding groove 31e that holds the sensor cable 80 is provided on the second cover part C2 side of the bottom wall part 31 of the cover 30. Here, the sensor cable 80 is thicker than each of the power supply lines 70u, 70v, and 70w. Therefore, the width dimension of the fourth holding groove 31e is larger than the width dimensions of the first, second, and third holding grooves 31b, 31c, and 31d.

Furthermore, a relatively large storage space SP for storing the sensor cable 80 is provided on the second cover portion C2 side of the cover 30 and near the fourth holding groove 31e. This allows the sensor cable 80 to bend significantly with slack inside the cover 30 (see Figures 6 and 7), and thus allows the sensor cable 80 to be routed between the sensor board 50 and the fourth holding groove 31e without being forcibly bent.

In this way, when the cover 30 is divided into a first cover part C1 on one side and a second cover part C2 on the other side with respect to the radial direction of the rotor 42 (see Figure 3) centered on the line segment CT, the U-phase, V-phase, and W-phase power supply lines 70u, 70v, and 70w are arranged on the first cover part C1 side of the cover 30, and the sensor cable 80 is arranged on the second cover part C2 side of the cover 30.

This prevents the power supply lines 70u, 70v, 70w and the sensor cable 80 from contacting or crossing each other inside the cover 30. This reliably prevents short circuits between the power supply lines 70u, 70v, 70w and the sensor cable 80, improving the reliability of the motor 10. Furthermore, the power supply lines 70u, 70v, 70w and the sensor cable 80 can be easily routed to the cover 30, which in turn improves the ease of assembly of the motor 10.

Here, the first cover part C1 corresponds to the power supply line arrangement part in the present invention, and the second cover part C2 corresponds to the sensor cable arrangement part in the present invention. In other words, the first cover part C1 is arranged on one side of the rotor 42 of the cover 30 in the radial direction, and the second cover part C2 is arranged on the other side of the rotor 42 of the cover 30 in the radial direction.

As shown in FIG. 5, a total of four board support columns 31f are provided on the bottom wall portion 31 of the cover 30. Two of these board support columns 31f are provided on each of the first cover portion C1 side and the second cover portion C2 side. In other words, the sensor board 50 supported by these board support columns 31f is fixed to the cover 30 so as to straddle the line segment CT.

The sensor board 50 is positioned by positioning protrusions Pt provided on two of the four board support columns 31f, and is fixed to the other two board support columns 31f by tightening a pair of fixing screws SC5 (see Figures 6 and 7).

As shown in Figures 6, 7, and 9, the sensor board 50 is a printed circuit board that functions as an electronic circuit, with multiple electronic components including three Hall sensors (magnetic sensors) HS soldered to it. The sensor board 50 has a pair of short sides 51, a first long side (first side) 52 provided on the wiring insertion hole 32a side, and a second long side (second side) 53 provided on the opposite side to the wiring insertion hole 32a side (the engaging protrusion 36a side).

Three Hall sensors HS are arranged at a predetermined interval in a portion of the sensor board 50 near the second long side 53. These Hall sensors HS detect the rotation state (rotation speed, etc.) of the rotor 42, and face the permanent magnet 42b in the axial direction of the rotor 42 (see Figures 3 and 4). As a result, the three Hall sensors HS perform a switching operation in response to the changeover of the N pole and S pole of the permanent magnet 42b as the rotor 42 rotates, and each outputs a rectangular wave at a predetermined timing.

The sensor cable 80 is electrically connected to the second long side 53 of the sensor board 50. Specifically, as shown in FIG. 12(a), the sensor cable 80 has a total of six cable cores (cores) 81. The cable cores 81 are thinner electric wires than the U-phase, V-phase, and W-phase power supply lines 70u, 70v, and 70w (see FIG. 7).

The cable core 81 is covered with an insert 82 made of cotton thread, synthetic fiber, or the like, and the cable core 81 and insert 82 are covered with a shield 83 made of aluminum foil or the like and a resin sheath 84. The insert 82, shield 83, and sheath 84 that cover the cable core 81 correspond to the covering member in this invention. The six cable cores 81 are electrically connected to predetermined locations (not shown in detail) of the sensor board 50 by soldering.

The connection portion of the cable core 81 with the sensor board 50 is fixed by soldering and has a relatively low rigidity. Therefore, if a large tensile force is applied to the sensor cable 80, there is a risk of solder cracks (poor electrical continuity). Therefore, in this embodiment, the sensor cable 80 is curved significantly in the accommodation space SP with some slack, as shown in Figures 6 and 7.

As a result, even if the sensor cable 80 is pulled slightly, the curved portion of the sensor cable 80 will bend, effectively preventing the transmission of the tensile force to the soldered portion of the cable core 81. Therefore, in this embodiment, solder cracks are less likely to occur, and sufficient durability is ensured.

Furthermore, as shown in Figs. 5 and 10, the fourth holding groove 31e that houses the sensor cable 80 is provided with a cable support protrusion 31g that protrudes toward the fall-off prevention plate 90. Specifically, the cable support protrusion 31g is disposed closer to the wiring insertion hole 32a in the longitudinal direction of the fourth holding groove 31e. The cable support protrusion 31g has the function of elastically deforming the sensor cable 80 from the bottom wall portion 31 side.

As shown in Figures 1, 2, 4, and 6, the longitudinal ends of the U-phase, V-phase, and W-phase power supply lines 70u, 70v, and 70w drawn out to the outside of the cover 30 are provided with a first connector connection part CN1 to which an external power supply connector (not shown) connected to a controller or the like is connected. In addition, the longitudinal end of the sensor cable 80 drawn out to the outside of the cover 30 is provided with a second connector connection part CN2 to which an external control connector (not shown) connected to a controller or the like is connected.

In this way, by separating the power supply system cables (power supply lines 70u, 70v, 70w) and the control system cables (sensor cable 80), it is possible to prevent electrical noise and other issues radiated from the power supply system cables from adversely affecting the control system cables.

As shown in Figures 6, 8, and 9, the fall-off prevention plate 90 attached inside the cover 30 is formed in a substantially disk-like shape from a resin material such as plastic. The fall-off prevention plate 90 has the function of preventing the U-phase, V-phase, and W-phase power supply lines 70u, 70v, and 70w and the sensor cable 80 from falling off the first, second, third, and fourth holding grooves 31b, 31c, 31d, and 31e (see Figure 7), i.e., from falling off the cover 30.

The fall-prevention plate 90 has a first surface 91 (see FIG. 8) on the bottom wall 31 side, and a second surface 92 (see FIG. 6 and FIG. 9) on the flat motor 40 side. The fall-prevention plate 90 also has a first cutout 93 cut into a substantially rectangular shape, and a second cutout 94 cut into a substantially semicircular shape at the approximate center of the fall-prevention plate 90. The sensor board 50 is disposed in the first cutout 93, as shown in FIG. 9. The rotor shaft 45 is disposed in the second cutout 94, as shown in FIG. 3. Furthermore, as shown in FIG. 6 and FIG. 8, the outer periphery of the fall-prevention plate 90 has a third cutout 95 into which the engaging protrusion 36b provided on the cover 30 fits when the motor 10 is assembled.

As shown in FIG. 8, a cable pressing protrusion 91a is integrally provided on the first surface 91 side of the fall-off prevention plate 90 and on the radially outer portion of the fall-off prevention plate 90. The cable pressing protrusion 91a protrudes from the first surface 91 toward the bottom wall portion 31 of the cover 30 in the axial direction of the rotor 42 (see FIG. 3), and is formed in a tapered shape of a substantially triangle. And, as shown in FIG. 10, the cable pressing protrusion 91a faces the cable support protrusion 31g of the cover 30.

That is, the cable support protrusion 31g is disposed at a position facing the cable pressing protrusion 91a on the cover 30, and protrudes toward the cable pressing protrusion 91a. Here, the cable pressing protrusion 91a corresponds to the first protrusion in the present invention, and the cable support protrusion 31g corresponds to the second protrusion in the present invention.

As shown in Figures 6 and 8, the radially outer portion of the fall-off prevention plate 90 has a total of five screw holes 96 arranged in a circumferential direction. Fixing screws SC6 (a total of five) are inserted into each of these screw holes 96, so that the fall-off prevention plate 90 covers the first, second, third, and fourth retaining grooves 31b, 31c, 31d, and 31e (see Figure 7) and is attached (fixed) to the inside of the cover 30 without rattling.

When the fall prevention plate 90 is fixed to the cover 30, the distance between the cable pressing protrusion 91a and the cable support protrusion 31g is S as shown in FIG. 12(b), and at the portion of the distance S, the sensor cable 80 is elastically deformed as if being crushed, and is clamped between the cable pressing protrusion 91a and the cable support protrusion 31g.

Specifically, as shown in FIG. 12(a), the diameter dimension D of the sensor cable 80 in its natural state (not elastically deformed) is set to approximately 5.4 mm. Also, as shown in FIG. 12(b), the distance S between the cable pressing protrusion 91a and the cable support protrusion 31g is set to approximately 2.4 mm. In other words, the crushing allowance of the sensor cable 80 is "D-S = approximately 3.0 mm", and as a result, as shown in FIG. 10, the sensor cable 80 is firmly fixed between the cable pressing protrusion 91a and the cable support protrusion 31g. Also, because the cable pressing protrusion 91a has a tapered shape of an approximately triangle, it bites into the sensor cable 80. Therefore, the pull-out strength of the sensor cable 80 against the pulling force is sufficiently increased.

In this embodiment, the maximum crushing allowance at which each cable core 81 can function as a sensor cable 80 without breaking or the like is approximately 2.5 mm to 3.5 mm (a value based on test results). Specifically, as shown in FIG. 12(b), when the sensor cable 80 is clamped between the cable pressing protrusion 91a and the cable support protrusion 31g, the cable pressing protrusion 91a and the cable support protrusion 31g elastically deform only the interposer 82, the shield 83, and the sheath 84, and do not deform each cable core 81. Therefore, no excessive load is applied to each cable core 81 from the cable pressing protrusion 91a and the cable support protrusion 31g, and the cable core 81 will not deform or break.

In addition, even if the sensor cable 80 is pulled when the electric motor 10 is installed in an electric transport vehicle (not shown), the sensor cable 80 is firmly fixed in place by being crushed between the cable pressing protrusion 91a and the cable support protrusion 31g, so that the pulling force does not reach the sensor board 50, and the occurrence of defects such as solder cracks is reliably prevented.

Furthermore, as shown in FIG. 8, screw holes 96 are provided on both sides of the cable pressing protrusion 91a. This prevents the portion of the fall prevention plate 90 near the cable pressing protrusion 91a from elastically deforming, thereby ensuring stable fixing strength of the sensor cable 80 by the cable pressing protrusion 91a and the cable support protrusion 31g.

6, 8, and 9, a total of three support protrusions 97 are integrally provided on the second surface 92 side of the fall-prevention plate 90 and on the radially outer portion of the fall-prevention plate 90, lined up in the circumferential direction. These support protrusions 97 protrude from the second surface 92 toward the flat motor 40 (see FIGS. 3 and 4), and are formed in a substantially rectangular parallelepiped shape. As shown in FIG. 9, when the fall-prevention plate 90 is attached to the cover 30, each support protrusion 97 faces the terminal holders 35a, 35b, and 35c in the radial direction of the cover 30.

Each support protrusion 97 supports the side of the flat female terminals M1, M2, M3. This prevents the flat female terminals M1, M2, M3 from tilting relative to the terminal holders 35a, 35b, 35c when connecting the flat male terminals T1, T2, T3 (see FIG. 4) on the case 20 side to the flat female terminals M1, M2, M3. This ensures that the flat male terminals T1, T2, T3 can be electrically connected to the flat female terminals M1, M2, M3.

As described above in detail, according to the electric motor 10 of this embodiment, the anti-fall-out plate 90 is provided with a cable pressing protrusion 91a that protrudes toward the cover 30 in the axial direction of the rotor 42, and the sensor cable 80 having the spacer 82, shield 83, and sheath 84 is clamped between the cable pressing protrusion 91a and the cable support protrusion 31g of the cover 30, and the spacer 82, shield 83, and sheath 84 are elastically deformed by the cable pressing protrusion 91a.

As a result, simply by fixing the anti-fall plate 90 to the cover 30, the fixing strength of the sensor cable 80 to the cover 30 can be sufficiently ensured and assembly can be easily performed.

In addition, according to the electric motor 10 of this embodiment, the cover 30 is provided with a cable support protrusion 31g that protrudes toward the cable pressing protrusion 91a and elastically deforms the interposer 82, the shield 83, and the sheath 84.

As a result, as shown in FIG. 10, the upper and lower portions of the sensor cable 80 can be partially elastically deformed. This allows the sensor cable 80 to be fixed to the cover 30 with a higher fixing strength, making it possible to more reliably prevent the occurrence of solder cracks.

Furthermore, according to the electric motor 10 of this embodiment, the cable pressing protrusion 91a and the cable support protrusion 31g elastically deform only the interposer 82, the shield 83, and the sheath 84, and do not deform the respective cable core wires 81.

This makes it possible to maintain the functionality of the sensor cable 80 for a long period of time without breaking the cable core 81 that forms the sensor cable 80, thereby further improving reliability.

In addition, according to the electric motor 10 of this embodiment, the cover 30 is provided with a first cover part C1 in which the U-phase, V-phase, and W-phase power supply lines 70u, 70v, and 70w are arranged, and a second cover part C2 in which the sensor cable 80 is arranged, and the first cover part C1 is arranged on one side of the cover 30 in the radial direction of the rotor 42, and the second cover part C2 is arranged on the other side of the cover 30 in the radial direction of the rotor 42.

This prevents the power supply lines 70u, 70v, 70w and the sensor cable 80 from contacting or crossing each other inside the cover 30. This reliably prevents the power supply lines 70u, 70v, 70w and the sensor cable 80 from shorting out, thereby improving the reliability of the motor 10. In addition, the power supply lines 70u, 70v, 70w and the sensor cable 80 can be easily routed to the cover 30, thereby improving the assembly workability of the motor 10.

Furthermore, according to the electric motor 10 of this embodiment, the cover 30 is provided with a wiring insertion hole 32a for drawing the sensor cable 80 to the outside of the cover 30, and the sensor board 50 has a first long side portion 52 provided on the wiring insertion hole 32a side and a second long side portion 53 provided on the opposite side to the wiring insertion hole 32a side, and the sensor cable 80 is electrically connected to the second long side portion 53 side of the sensor board 50 and is curved inside the cover 30.

This allows the sensor cable 80 to be routed between the sensor board 50 and the fourth holding groove 31e without forcibly bending it, and even if the sensor cable 80 is pulled slightly, the curved portion of the sensor cable 80 will bend, effectively preventing the transmission of the tensile force to the soldered portion of the cable core 81. This makes it difficult for solder cracks to occur, and ensures sufficient durability.

In addition, the electric motor 10 according to this embodiment can improve the durability of the electric motor 10 and improve the ease of assembly, thereby lengthening the product life cycle and reducing the energy required for production. This can contribute to the Sustainable Development Goals (SDGs) led by the United Nations, particularly Goal 7 (Ensure access to affordable, reliable, sustainable and modern energy) and Goal 13 (Take urgent action to combat climate change and its impacts).

The present invention is not limited to the above embodiment, and it goes without saying that various modifications are possible without departing from the gist of the invention. In the above embodiment, the electric motor 10 is applied to an electric transport vehicle that transports harvested crops, etc., but the present invention is not limited to this, and can also be applied to devices for other purposes, such as as a driving source for welfare equipment such as wheelchair devices.

The material, shape, dimensions, number, installation location, etc. of each component in the above embodiment are arbitrary as long as they can achieve the present invention, and are not limited to the above embodiment.

10: motor, 20: case, 21: large diameter cylinder, 22: small diameter cylinder, 23: partition wall, 23a: through hole, 30: cover (housing), 31: bottom wall, 31b: first retaining groove, 31c: second retaining groove, 31d: third retaining groove, 31e: fourth retaining groove, 31f: board support column, 31g: cable support convex part (second convex part), 32: side wall, 32a: wiring insertion hole (cable pull-out part), 33: grommet, 33a: small diameter hole, 33b: large diameter hole, 34: fixing plate, 35a, 35b, 35c: terminal holder, 36a, 3 6b: engagement protrusion, 40: flat motor, 41: stator core (stator), 42: rotor, 42a: main body, 42b: permanent magnet, 43: insulator, 44: coil, 45: rotor shaft, 45a: shaft main body, 45b: first shaft portion, 45b: first shaft portion, 45c: second shaft portion, 50: sensor board, 51: short side portion, 52: first long side portion (first side portion), 53: second long side portion (second side portion), 60: hypocycloid reducer, 61: outer gear, 61a: teeth portion, 62: inner gear, 62a: first teeth portion, 62b: second Teeth portion, 63: output rotor, 63a: teeth portion, 64: cover member, 70u: U-phase power supply line (power supply line), 70v: V-phase power supply line (power supply line), 70w: W-phase power supply line (power supply line), 80: sensor cable, 81: cable core (core wire), 82: interposition (coating member), 83: shield (coating member), 84: sheath (coating member), 90: fall prevention plate, 91: first surface, 91a: cable pressing protrusion (first convex portion), 92: second surface, 93: first notch portion, 94: second notch portion, 95: third notch portion, 96: screw hole, 97: support Protrusion, B1: First ball bearing, B2: Second ball bearing, B3: Third ball bearing, B4: Fourth ball bearing, C1: First cover part (power supply line arrangement part), C2: Second cover part (sensor cable arrangement part), CN1: First connector connection part, CN2: Second connector connection part, CT: Line segment, HS: Hall sensor (magnetic sensor), M1, M2, M3: Flat female terminal, MS: Motor housing, Pt: Positioning protrusion, RS: Reducer housing, SP: Housing space, T1, T2, T3: Flat male terminal

Claims (5)

A stator on which a coil is wound;
a rotor that rotates relative to the stator;
An electric motor having
A plurality of power supply lines for supplying power to the coil;
a terminal fixed to a base end of the power supply line in a longitudinal direction;
a sensor substrate provided with a magnetic sensor for detecting a rotation state of the rotor;
a sensor cable electrically connected to the sensor board and including a plurality of core wires;
a housing for holding the plurality of power supply lines and the sensor cable;
a drop-out prevention plate attached to the housing to prevent the power supply lines and the sensor cable from dropping out of the housing;
having
the sensor cable includes a covering member that covers the plurality of core wires,
the fall-off prevention plate is provided with a first protrusion protruding toward the housing in the axial direction of the rotor, and a support protrusion supporting a side of the terminal in a radial direction of the fall-off prevention plate,
the sensor cable is sandwiched between the first protrusion and the housing, and the covering member is elastically deformed by the first protrusion.
Electric motor. 2. The electric motor according to claim 1,
The housing is provided with a second protrusion that protrudes toward the first protrusion and elastically deforms the covering member.
Electric motor. The first convex portion and the second convex portion elastically deform only the covering member and do not deform the core wire.
3. The electric motor according to claim 2. The electric motor according to any one of claims 1 to 3,
the housing is provided with a power feed line arrangement section in which the plurality of power feed lines are arranged and a sensor cable arrangement section in which the sensor cable is arranged,
the power supply line arrangement portion is arranged on one side of the housing in a radial direction of the rotor,
the sensor cable arrangement portion is arranged on the other side of the housing in the radial direction of the rotor,
Electric motor. The electric motor according to any one of claims 1 to 4,
the housing is provided with a cable outlet portion through which the sensor cable is led out to the outside of the housing,
the sensor board includes a first side portion provided on the cable outlet side and a second side portion provided on the opposite side to the cable outlet side,
the sensor cable is electrically connected to the second side of the sensor board and is curved inside the housing,
Electric motor.

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