Electric drive system and electric power steering system

Abstract

To provide an electric drive device and an electric power steering device that can maintain sufficient waterproofness even under high water pressure.SOLUTION: An electric drive device includes a motor and an electronic control device that controls rotation of the motor. The electronic control device includes a circuit board, a second housing, a metal lid covering the second housing, and a connector attached to the lid. The connector includes a base, a socket protruding from the base toward the opposite load side, a connector terminal inserted into a through hole of the lid, and a sealing member. The base includes an eaves portion that has an outer edge protruding toward the load side from the back surface of the base, surrounds the outer edge of the connector pedestal portion of the lid, and covers a part of the side surface of the connector pedestal portion, and a sealing support portion that protrudes from the back side of the base toward the load side and is inserted into the through hole of the lid together with the connector terminal. The sealing member is sandwiched between a first inner wall of the through hole and the sealing support portion.SELECTED DRAWING: Figure 18

Description

Technical Field

[0001] The present disclosure relates to an electric drive device and an electric power steering device including an electronic control device that controls the rotation of a motor.

Background Art

[0002] An electric power steering device that generates auxiliary steering torque by a motor includes an electronic control device that is a device for controlling the motor. For example, Patent Documents 1 to 3 describe drive devices in which a motor and a control unit that controls the motor are integrated.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] The electric drive devices of Patent Documents 1 to 3 have an O-ring to suppress the intrusion of moisture into the interior.

[0005] However, the requirement for the waterproof level of the electric drive device is increasing, and it is required to maintain sufficient waterproofness even under high water pressure. For example, the electric drive device is required to satisfy IPx9K of the standard JIS D 5020.

[0006] The present disclosure has been made in view of the above problems, and an object thereof is to provide an electric drive device and an electric power steering device capable of maintaining sufficient waterproofness even under high water pressure. [Means for solving the problem]

[0007] To achieve the above objective, an electric drive device according to one embodiment comprises a motor and an electronic control device for controlling the rotation of the motor, wherein the motor includes a shaft extending axially from the load side to the non-load side, a motor rotor interlocked with the shaft, a motor coil, a motor coil wiring for supplying power to the motor coil, a motor stator for rotating the motor rotor, and a first housing housing the motor rotor and the motor stator inside, the electronic control device includes a circuit board, a second housing, a metal lid that houses at least a portion of the circuit board between itself and the second housing and covers the second housing, and a connector attached to the lid, wherein the lid has a first surface and a portion of the lid from the first surface The connector base portion has a second surface on the non-load side that protrudes to the non-load side, and a side surface between the first surface and the second surface, and a through hole that penetrates the connector base portion from the second surface on the non-load side to the back surface on the load side, and the connector has a base portion, a socket portion that protrudes from the base portion on the non-load side and receives a plug, a connector terminal that is inserted into the through hole, and a sealing member, and the base portion has a canopy portion whose outer edge protrudes to the load side beyond the back surface of the base portion, surrounds the outer edge of the connector base portion, and covers a part of the side surface of the connector base portion, and a sealing support portion that protrudes to the load side beyond the back surface of the base portion together with the connector terminal, is inserted into the through hole, and is arranged around the connector terminal, and the sealing member is sandwiched between the first inner wall of the through hole and the sealing support portion.

[0008] As a result, even if high-pressure water attempts to enter from the outside, the eaves will prevent water from entering. Even if water penetrates beyond the eaves, the sealing member sandwiched between the first inner wall of the through-hole and the sealing support will prevent further water intrusion. Consequently, the waterproofing level of the electric drive device is improved, and sufficient waterproofing can be maintained even under high water pressure.

[0009] In a desirable configuration, the back surface of the base and the second surface of the lid are in close contact. This ensures that even if water penetrates beyond the overhang, the contact surface between the back surface of the base and the second surface of the lid prevents water from entering.

[0010] In a preferred embodiment, the through-hole has a first inner wall having a first diameter, a second inner wall having a second diameter smaller than the first diameter, and a first bottom between the first and second inner walls, and the sealing member is housed in a seal housing space surrounded by the back surface of the base, the first inner wall, the first bottom, and the sealing support portion. As a result, the side surface of the sealing member sandwiched between the first inner wall of the through-hole and the sealing support portion is subjected to pressure, causing the sealing member to deform.

[0011] In a desirable embodiment, there is a gap between the back surface of the base and the sealing member, and between the first bottom and the sealing member, at least one of these gaps. This prevents deformation of the sealing member from widening the gap between the back surface of the base and the second surface of the lid, thus maintaining a tight seal between the back surface of the base and the second surface of the lid.

[0012] In a preferred embodiment, the through-hole has a third inner wall having a third diameter smaller than the second diameter, and a second bottom between the second and third inner walls, with the sealing support portion in contact with the second inner wall but not with the second bottom. This enhances the airtightness of the seal containment space.

[0013] In a preferred embodiment, the through-hole has a third inner wall having a third diameter smaller than the second diameter, and a second bottom between the second and third inner walls. The seal housing space is filled with grease along with the sealing member, and has a groove provided in the second bottom that recesses toward the load side. Even if grease leaks from the seal housing space, the grease is stored in the recess of the groove. As a result, the grease is less likely to enter the second housing and adversely affect the circuit board or the like.

[0014] In a preferred embodiment, the sealing support portion is cylindrical in shape. This improves the accuracy of resin molding and stabilizes the shape of the sealing support portion. As a result, the airtightness of the seal housing space is improved.

[0015] In a preferred embodiment, the base of the connector and the cover are connected by a plurality of fixing members, and a plurality of connector holes are drilled in the base through which each of the fixing members passes, and the angle between the centers of adjacent connector holes and the center of the sealing support portion is equal. As a result, when the base of the connector is attached to the cover and the sealing support portion is inserted into the through-hole together with the connector terminals, the sealing support portion presses the sealing member against the first wall portion, causing the sealing member to be compressed naturally. Then, when the fixing members are fastened, stress is applied that presses the base of the connector against the cover. Since the fixing members are arranged at equiangled angles around the sealing member, it is less likely to cause unintended deformation of the sealing member. As a result, the lifespan of the sealing member is extended and the reliability of the electric drive device is improved.

[0016] In a preferred embodiment, the distance between the eaves and the first surface of the cover is narrower than the distance between the eaves and the side surface of the connector base. As a result, even if water penetrates beyond the eaves, the space between the eaves and the side surface of the connector base is larger than the space between the eaves and the first surface of the cover, making it difficult for water to reach the area between the back surface of the base and the second surface of the cover. Consequently, the waterproof level of the electric drive device is improved, and sufficient waterproofing can be maintained even under high water pressure.

[0017] As a desirable aspect, the circuit board is mounted with a transistor that outputs a current for exciting the motor coil and a rotation angle sensor disposed on an extension line in the axial direction of the shaft. The circuit board has a first circuit board disposed on the load side of the second housing and a second circuit board disposed on the non-load side of the second housing and having a control circuit for controlling a power circuit having the transistor. The lid body houses the second circuit board between the lid body and the second housing, and the first housing houses the first circuit board. Thereby, the second housing suppresses heat generation of the first circuit board and the second circuit board. As a result, the area of the first circuit board is suppressed, and the size of the electronic control device in the radial direction becomes smaller. Further, the heat dissipation of the first circuit board can be enhanced. As a result, the temperature rise in the second heat sink is suppressed.

[0018] As a desirable aspect, the electric power steering device includes the electric drive device described above, and the electric drive device generates an auxiliary steering torque. As described above, the electric drive device can improve waterproof performance even under high water pressure. As a result, the reliability of the electric drive device is improved, and thus the reliability of the electric power steering device is also improved.

Advantages of the Invention

[0019] According to the present disclosure, it is possible to provide an electric drive device and an electric power steering device that can maintain sufficient waterproof performance even under high water pressure.

Brief Description of the Drawings

[0020] [Figure 1] FIG. 1 is a perspective view schematically showing a vehicle equipped with an electric power steering device according to Embodiment 1. [Figure 2] FIG. 2 is a schematic diagram of the electric power steering device according to Embodiment 1. [Figure 3] FIG. 3 is an exploded perspective view showing the electric drive device according to Embodiment 1. [Figure 4] FIG. 4 is a cross-sectional view schematically showing a cross section of the motor according to Embodiment 1. [Figure 5] FIG. 5 is a schematic diagram showing the wiring of the motor according to Embodiment 1. [Figure 6] FIG. 6 is an explanatory diagram showing the relationship between the motor and the ECU according to Embodiment 1. [Figure 7] FIG. 7 is a perspective view showing a configuration example of the ECU according to Embodiment 1. [Figure 8] FIG. 8 is an exploded perspective view showing a configuration example of the ECU according to Embodiment 1. [Figure 9A] FIG. 9A is an exploded perspective view showing a configuration example of attaching the terminal block to the power substrate according to Embodiment 1. [Figure 9B] FIG. 9B is an exploded perspective view showing a configuration example of attaching the motor coil wiring to the terminal block according to Embodiment 1. [Figure 10] FIG. 10 is a perspective view showing a configuration example of attaching the terminal block to the power substrate according to Embodiment 1. [Figure 11] FIG. 11 is an exploded perspective view showing a configuration example of attaching the control substrate to the wiring module according to Embodiment 1. [Figure 12A] FIG. 12A is a top perspective view of the heat sink according to Embodiment 1. [Figure 12B] FIG. 12B is an explanatory diagram for explaining the positional relationship between the heat dissipation surface of the heat sink and the second circuit board according to Embodiment 1. [Figure 12C] FIG. 12C is a top perspective view of the second circuit board according to Embodiment 1. [Figure 13] FIG. 13 is a perspective view showing the top surface of the lid and the connector according to Embodiment 1. [Figure 14] FIG. 14 is a perspective view showing the back surface of the lid according to Embodiment 1. [Figure 15] FIG. 15 is a cross-sectional view showing the cross-section of the electric drive device according to Embodiment 1. [Figure 16] FIG. 16 is a perspective view showing the back surface of the connector according to Embodiment 1. [Figure 17] FIG. 17 is an exploded cross-sectional view of the lid and the connector according to Embodiment 1. [Figure 18] Figure 18 is a cross-sectional view of the assembled lid and connector according to Embodiment 1. [Figure 19] Figure 19 is a circuit diagram showing the equivalent circuit of the power wiring module of Embodiment 1. [Figure 20] Figure 20 is an exploded cross-sectional view of the cover and connector according to Embodiment 2. [Figure 21] Figure 21 is a cross-sectional view of the assembled lid and connector according to Embodiment 2. [Figure 22] Figure 22 is an explanatory diagram illustrating the position of the connector hole through which the fixing member passes in the connector according to Embodiment 3. [Figure 23] Figure 23 is a schematic diagram of an electric power steering system according to Embodiment 4. [Figure 24] Figure 24 is a schematic diagram of an electric power steering system according to Embodiment 5. [Figure 25] Figure 25 is a schematic diagram of an electric power steering system according to Embodiment 6. [Modes for carrying out the invention]

[0021] Embodiments for implementing this disclosure will be described in detail with reference to the drawings. This disclosure is not limited to the embodiments described below. Furthermore, the components described below include those that are easily conceivable to those skilled in the art, and those that are substantially the same. In addition, the components described below can be combined as appropriate.

[0022] Figure 1 is a schematic perspective view of a vehicle equipped with an electric power steering system according to Embodiment 1. Figure 2 is a schematic diagram of the electric power steering system according to Embodiment 1. As shown in Figure 1, the vehicle 101 is equipped with an electric power steering system 100. The outline of the electric power steering system 100 will be explained with reference to Figure 2.

[0023] The electric power steering system 100 includes, in the order in which the force applied by the driver (operator) is transmitted, a steering wheel 191, a steering shaft 192, a universal joint 196, an intermediate shaft 197, a universal joint 198, a first rack and pinion mechanism 199, and a tie rod 172. The electric power steering system 100 also includes a torque sensor 194 for detecting the steering torque of the steering shaft 192, a motor 30, an electronic control unit (hereinafter referred to as ECU (Electronic Control Unit)) 10 for controlling the motor 30, a reduction gear 175, and a power transmission mechanism 173. A vehicle speed sensor 182, a power supply unit 183 (e.g., an on-board battery), and an ignition switch 184 are installed in the vehicle body. The vehicle speed sensor 182 detects the driving speed of the vehicle 101. The vehicle speed sensor 182 outputs the detected vehicle speed signal SV to the ECU 10 via CAN (Controller Area Network) communication. The ECU10 is supplied with power from the power supply unit 183 when the ignition switch 184 is turned on.

[0024] The electric drive unit 1 comprises a motor 30 and an ECU 10 fixed to the non-load side of the motor 30's shaft 31. The electric drive unit 1 may also include an adapter connecting the ECU 10 and the motor 30.

[0025] As shown in Figure 2, the steering shaft 192 comprises an input shaft 192A, an output shaft 192B, and a torsion bar 192C. One end of the input shaft 192A is connected to the steering wheel 191, and the other end is connected to the torsion bar 192C. One end of the output shaft 192B is connected to the torsion bar 192C, and the other end is connected to a universal joint 196. The torque sensor 194 detects the steering torque applied to the steering shaft 192 by detecting the twist of the torsion bar 192C. The torque sensor 194 outputs a steering torque signal T to the ECU 10 corresponding to the detected steering torque. The steering shaft 192 rotates due to the steering force applied to the steering wheel 191.

[0026] The intermediate shaft 197 has an upper shaft 197A and a lower shaft 197B, and transmits torque from the output shaft 192B. The upper shaft 197A is connected to the output shaft 192B via a universal joint 196. Meanwhile, the lower shaft 197B is connected to the first pinion shaft 199A of the first rack and pinion mechanism 199 via a universal joint 198. The upper shaft 197A and the lower shaft 197B are, for example, spline-coupled.

[0027] The first rack and pinion mechanism 199 includes a first pinion shaft 199A, a first pinion gear 199B, a rack shaft 199C, and a first rack 199D. One end of the first pinion shaft 199A is connected to the lower shaft 197B via a universal joint 198, and the other end is connected to the first pinion gear 199B. The first rack 199D formed on the rack shaft 199C meshes with the first pinion gear 199B. The rotational motion of the steering shaft 192 is transmitted to the first rack and pinion mechanism 199 via the intermediate shaft 197. This rotational motion is converted into linear motion of the rack shaft 199C by the first rack and pinion mechanism 199. Tie rods 172 are connected to both ends of the rack shaft 199C, respectively.

[0028] Motor 30 is a motor that generates auxiliary steering torque to assist the driver's steering. Motor 30 may be a brushless motor or a brushed motor having brushes and a commutator.

[0029] The ECU 10 is equipped with a rotation angle sensor 23a. The rotation angle sensor 23a detects the rotation phase of the motor 30. The ECU 10 obtains the rotation phase signal of the motor 30 from the rotation angle sensor 23a, the steering torque signal T from the torque sensor 194, and the vehicle speed signal SV of the vehicle 101 from the vehicle speed sensor 182. Based on the rotation phase signal, the steering torque signal T, and the vehicle speed signal SV, the ECU 10 calculates an auxiliary steering command value for the assist command. Based on the calculated auxiliary steering command value, the ECU 10 supplies current to the motor 30.

[0030] The electric power steering system 100 is a rack-parallel type. The shaft 31 of the motor 30 is connected to the power transmission mechanism 173. The power transmission mechanism 173 has a pulley 176 and a belt 177. The rotation of the belt 177 rotates the nut of the ball screw device 178. This provides an assist force to the rack shaft 199C based on the rotation of the shaft 31 of the motor 30.

[0031] The steering force input by the driver to the steering wheel 191 is transmitted to the first rack and pinion mechanism 199 via the steering shaft 192 and the intermediate shaft 197. The first rack and pinion mechanism 199 transmits the transmitted steering force to the rack shaft 199C as a force applied axially to the rack shaft 199C. At this time, the ECU 10 acquires the steering torque signal T input to the steering shaft 192 from the torque sensor 194. The ECU 10 acquires the vehicle speed signal SV from the vehicle speed sensor 182. The ECU 10 acquires the rotation phase signal of the motor 30 from the rotation angle sensor 23a. Then, the ECU 10 outputs a control signal to control the operation of the motor 30. The belt 177 rotates according to the auxiliary steering torque generated by the motor 30, and the nut of the ball screw device 178 rotates. As a result, an assist force is applied to the rack shaft 199C based on the rotation of the motor 30's shaft 31. In this way, the steering of the driver's steering wheel 191 is assisted by the electric power steering system 100.

[0032] As shown in Figure 2, the electric power steering system 100 is a rack-parallel system, but is not limited thereto. The electric power steering system 100 may also be a single-pinion assist system in which assist force is applied only to the first pinion gear 199B. The electric power steering system 100 may also be a dual-pinion system in which assist force is applied to the second rack-and-pinion mechanism 170. Not limited thereto, the electric power steering system 100 may also be a column assist system in which assist force is applied to the steering shaft 192, for example.

[0033] Figure 3 is an exploded perspective view showing an electric drive device according to Embodiment 1. As shown in Figure 3, the electric drive device 1 comprises a motor 30 and an ECU 10 positioned on the non-load side of the motor 30. A gear 30G is located at the load-side end of the shaft 31 of the motor 30, and the gear 30G is inserted into the reduction gear 175 described above. In this embodiment, axial Ax refers to the direction parallel to the direction in which the shaft 31 of the motor 30 (see Figure 4) extends.

[0034] The motor 30 includes a first housing 930. The first housing 930 is cylindrical. The first housing 930 is also called the motor housing. The first housing 930 has a tool insertion hole 36H and a side cover 36 that covers the tool insertion hole 36H and is removable from the first housing 930. When the side cover 36 is removed from the first housing 930, the terminal block 80, which will be described later, is exposed through the tool insertion hole 36H.

[0035] Furthermore, the second housing 11, which is the enclosure of the ECU 10, is provided with a waterproof and breathable filter 10B. The waterproof and breathable filter 10B is breathable but waterproof, preventing moisture from entering. For example, if the pressure difference between the inside and outside of the ECU 10 increases due to temperature changes, air moves through the waterproof and breathable filter 10B to reduce the pressure difference.

[0036] Figure 4 is a schematic cross-sectional view showing a cross-section of the motor according to Embodiment 1. Figure 5 is a schematic diagram showing the wiring of the motor according to Embodiment 1. In this embodiment, the circumferential direction is the direction along the concentric circles centered on the shaft 31. The radial direction is the direction away from the shaft 31 in a plane perpendicular to the axial direction Ax. As shown in Figure 4, the motor 30 comprises a first housing 930, a motor stator 931, and a motor rotor 932. The cylindrical motor stator 931 includes a plurality of first motor coils 37 and a plurality of second motor coils 38. The motor stator 931 includes an annular back yoke 931a and a plurality of teeth 931b protruding from the inner circumferential surface of the back yoke 931a. There are 12 teeth 931b arranged in the circumferential direction. The motor rotor 932 includes a rotor yoke 932a and a magnet 932b. The magnets 932b are provided on the outer circumferential surface of the rotor yoke 932a. There are, for example, eight magnets 932b. The rotation of the motor rotor 932 is linked to the rotation of the shaft 31.

[0037] As shown in Figure 4, the first motor coil 37 is concentratedly wound on each of the multiple teeth 931b. The first motor coil 37 is concentratedly wound on the outer circumference of the teeth 931b via an insulator. All of the first motor coils 37 are included in the first coil system. The first coil system according to Embodiment 1 is supplied with current and excited by an inverter circuit 251 (see Figure 6) included in the first power circuit 25A. The first coil system includes, for example, six first motor coils 37. The six first motor coils 37 are arranged such that two first motor coils 37 are adjacent to each other in the circumferential direction. Three first coil groups Gr1, each consisting of adjacent first motor coils 37 as one group, are arranged at equal intervals in the circumferential direction. That is, the first coil system comprises three first coil groups Gr1 arranged at equal intervals in the circumferential direction. Note that the first coil groups Gr1 do not necessarily have to be three; it is sufficient if there are 3n first coil groups arranged at equal intervals in the circumferential direction, where n is a natural number. Furthermore, it is preferable that n is an odd number. As explained above, in this embodiment, there are multiple coil groups, and each of the three phases is divided into at least two systems: a first coil group gr1 and a second coil group Gr2, and the stator core is excited with three-phase AC.

[0038] As shown in Figure 4, the second motor coil 38 is concentratedly wound on each of several teeth 931b. The second motor coil 38 is concentratedly wound on the outer circumference of the teeth 931b via an insulator. The teeth 931b on which the second motor coil 38 is concentratedly wound are different teeth 931b from the teeth 931b on which the first motor coil 37 is concentratedly wound. All second motor coils 38 are included in the second coil system. The second coil system is supplied with current and excited by the inverter circuit 251 (see Figure 6) included in the second power circuit 25B. The second coil system includes, for example, six second motor coils 38. The six second motor coils 38 are arranged such that two second motor coils 38 are adjacent to each other in the circumferential direction. Three second coil groups Gr2, each consisting of adjacent second motor coils 38 as a group, are arranged at equal intervals in the circumferential direction. That is, the second coil system comprises three second coil groups Gr2 arranged at equal intervals in the circumferential direction. Note that the second coil group Gr2 does not necessarily have to consist of three coils; it is sufficient if there are 3n coils arranged at equal intervals in the circumferential direction, where n is a natural number. Furthermore, it is preferable that n is an odd number.

[0039] As shown in Figure 5, the six first motor coils 37 include two first U-phase motor coils 37Ua and 37Ub excited by a first U-phase current I1u, two first V-phase motor coils 37Va and 37Vb excited by a first V-phase current I1v, and two first W-phase motor coils 37Wa and 37Wb excited by a first W-phase current I1w. The first U-phase motor coil 37Ub is connected in series with the first U-phase motor coil 37Ua. The first V-phase motor coil 37Vb is connected in series with the first V-phase motor coil 37Va. The first W-phase motor coil 37Wb is connected in series with the first W-phase motor coil 37Wa. The winding direction of all first motor coils 37 with respect to teeth 931b is the same. Furthermore, the first U-phase motor coil 37Ub, the first V-phase motor coil 37Vb, and the first W-phase motor coil 37Wb are connected in a star connection (Y connection).

[0040] As shown in Figure 5, the six second motor coils 38 include two second U-phase motor coils 38Ua and 38Ub excited by a second U-phase current I2u, two second V-phase motor coils 38Va and 38Vb excited by a second V-phase current I2v, and two second W-phase motor coils 38Wa and 38Wb excited by a second W-phase current I2w. The second U-phase motor coils 38Ub are connected in series with the second U-phase motor coils 38Ua. The second V-phase motor coils 38Vb are connected in series with the second V-phase motor coils 38Va. The second W-phase motor coils 38Wb are connected in series with the second W-phase motor coils 38Wa. The winding direction of all the second motor coils 38 with respect to the teeth 931b is the same direction, and is the same as the winding direction of the first motor coil 37. Furthermore, the second U-phase motor coil 38Ub, the second V-phase motor coil 38Vb, and the second W-phase motor coil 38Wb are connected in a star connection (Y-connection).

[0041] As shown in Figure 4, the three first coil groups Gr1 consist of a first UV coil group Gr1UV, a first VW coil group Gr1VW, and a first UW coil group Gr1UW. The first UV coil group Gr1UV includes a first U-phase motor coil 37Ub and a first V-phase motor coil 37Va that are adjacent to each other in the circumferential direction. The first VW coil group Gr1VW includes a first V-phase motor coil 37Vb and a first W-phase motor coil 37Wa that are adjacent to each other in the circumferential direction. The first UW coil group Gr1UW includes a first U-phase motor coil 37Ua and a first W-phase motor coil 37Wb that are adjacent to each other in the circumferential direction.

[0042] As shown in Figure 4, the three second coil groups Gr2 consist of a second UV coil group Gr2UV, a second VW coil group Gr2VW, and a second UW coil group Gr2UW. The second UV coil group Gr2UV includes a second U-phase motor coil 38Ub and a second V-phase motor coil 38Va that are adjacent to each other in the circumferential direction. The second VW coil group Gr2VW includes a second V-phase motor coil 38Vb and a second W-phase motor coil 38Wa that are adjacent to each other in the circumferential direction. The second UW coil group Gr2UW includes a second U-phase motor coil 38Ua and a second W-phase motor coil 38Wb that are adjacent to each other in the circumferential direction.

[0043] The first motor coil 37, which is excited by the first U-phase current I1u, faces the second motor coil 38, which is excited by the second U-phase current I2u, in the radial direction of the motor stator 931. In the following description, the radial direction of the motor stator 931 will be simply referred to as the radial direction. For example, as shown in Figure 4, the first U-phase motor coil 37Ua faces the second U-phase motor coil 38Ua in the radial direction, and the first U-phase motor coil 37Ub faces the second U-phase motor coil 38Ub.

[0044] The first motor coil 37, which is excited by the first V-phase current I1v, faces the second motor coil 38, which is excited by the second V-phase current I2v, in the radial direction. For example, as shown in Figure 4, the first V-phase motor coil 37Va faces the second V-phase motor coil 38Va in the radial direction, and the first V-phase motor coil 37Vb faces the second V-phase motor coil 38Vb.

[0045] The first motor coil 37, which is excited by the first W-phase current I1w, faces the second motor coil 38, which is excited by the second W-phase current I2w, in the radial direction. For example, as shown in Figure 4, the first W-phase motor coil 37Wa faces the second W-phase motor coil 38Wa in the radial direction, and the first W-phase motor coil 37Wb faces the second W-phase motor coil 38Wb.

[0046] Figure 6 is a schematic diagram showing the relationship between the motor and the ECU according to Embodiment 1. As shown in Figure 6, the ECU 10 includes a detection circuit 23, a control circuit 24, a first power circuit 25A, and a second power circuit 25B. The detection circuit 23 includes a rotation angle sensor 23a and a motor rotation speed calculation unit 23b. The control circuit 24 includes a control calculation unit 241, a gate drive circuit 242, and a cutoff drive circuit 243. The first power circuit 25A includes an inverter circuit 251 and a current cutoff circuit 255. The second power circuit 25B includes an inverter circuit 251 and a current cutoff circuit 255. The inverter circuit 251 also includes a plurality of switching elements 252 and a shunt resistor SR for detecting the current value. The shunt resistor SR is connected to the operational amplifier OP of the current detection circuit 254. Note that in Figure 6, circuits that do not require explanation have been omitted as appropriate. The three shunt resistors SR are each connected to one of the three switching elements 252. Alternatively, there may be only one shunt resistor SR, and all three switching elements 252 may be connected to that single shunt resistor SR.

[0047] The control calculation unit 241 calculates the motor current command value. The motor rotation speed calculation unit 23b calculates the motor electrical angle θm and outputs it to the control calculation unit 241. The gate drive circuit 242 receives the motor current command value output from the control calculation unit 241 as input. The gate drive circuit 242 controls the first power circuit 25A and the second power circuit 25B based on the motor current command value. The gate drive circuit 242 includes a capacitor 256, which will be described later, in the power supply line.

[0048] As shown in Figure 6, the ECU10 is equipped with a rotation angle sensor 23a. The rotation angle sensor 23a is, for example, a magnetic sensor. The value detected by the rotation angle sensor 23a is supplied to the motor rotation speed calculation unit 23b. The motor rotation speed calculation unit 23b calculates the motor electrical angle θm based on the value detected by the rotation angle sensor 23a and outputs it to the control calculation unit 241.

[0049] The control calculation unit 241 receives the steering torque signal T detected by the torque sensor 194, the vehicle speed signal SV detected by the vehicle speed sensor 182, and the motor electrical angle θm output from the motor rotation speed calculation unit 23b as input. Based on the steering torque signal T, the vehicle speed signal SV, and the motor electrical angle θm, the control calculation unit 241 calculates a motor current command value and outputs it to the gate drive circuit 242.

[0050] The gate drive circuit 242 calculates a first pulse width modulation signal based on the motor current command value and outputs it to the inverter circuit 251 of the first power circuit 25A. The inverter circuit 251 switches the switching elements 252 to obtain three phase current values ​​according to the duty cycle of the first pulse width modulation signal, thereby generating a three-phase AC current including a first U-phase current I1u, a first V-phase current I1v, and a first W-phase current I1w. The first U-phase current I1u excites the first U-phase motor coils 37Ua and 37Ub, the first V-phase current I1v excites the first V-phase motor coils 37Va and 37Vb, and the first W-phase current I1w excites the first W-phase motor coils 37Wa and 37Wb.

[0051] The gate drive circuit 242 calculates a second pulse width modulation signal based on the motor current command value and outputs it to the inverter circuit 251 of the second power circuit 25B. The inverter circuit 251 switches the switching element 252 to obtain three-phase current values ​​according to the duty cycle of the second pulse width modulation signal, thereby generating a three-phase AC current including a second U-phase current I2u, a second V-phase current I2v, and a second W-phase current I2w. The second U-phase current I2u energizes the second U-phase motor coils 38Ua and 38Ub, the second V-phase current I2v energizes the second V-phase motor coils 38Va and 38Vb, and the second W-phase current I2w energizes the second W-phase motor coils 38Wa and 38Wb.

[0052] The inverter circuit 251 is a power conversion circuit that converts DC power to AC power. As described above, the inverter circuit 251 has a plurality of switching elements 252. The switching elements 252 are, for example, field-effect transistors. Capacitors 253 are connected in parallel to the inverter circuit 251. The first circuit board 60 includes a plurality of capacitors 253 connected in parallel.

[0053] Furthermore, as described above, a current detection circuit 254 is connected to the inverter circuit 251. The current detection circuit 254 is connected, for example, to a shunt resistor SR. The current value detected by the current detection circuit 254 is sent to the control calculation unit 241. The current detection circuit 254 may also be connected to detect the current value of each phase of the motor 30.

[0054] The current interruption circuit 255 is positioned between the inverter circuit 251 and either the first motor coil 37 or the second motor coil 38. If the current value detected by the current detection circuit 254 is determined to be abnormal, the control calculation unit 241 drives the current interruption circuit 255 via the interruption drive circuit 243 to interrupt the current flowing from the inverter circuit 251 to the first motor coil 37. The control calculation unit 241 also drives the current interruption circuit 255 via the interruption drive circuit 243 to interrupt the current flowing from the inverter circuit 251 to the second motor coil 38. In this way, the current flowing to the first motor coil 37 and the current flowing to the second motor coil 38 are controlled independently by the control calculation unit 241. Input and output signals such as the steering torque signal T and the vehicle speed signal SV are transmitted to the control calculation unit 241 via the connector CNT.

[0055] Figure 8 is a perspective view showing an example configuration of the ECU according to Embodiment 1. Figure 9A is an exploded perspective view showing an example configuration of the ECU according to Embodiment 1. Figure 9B is an exploded perspective view showing an example configuration of attaching the terminal block according to Embodiment 1 to the power board. Figure 10 is a perspective view showing an example configuration of attaching the terminal block according to Embodiment 1 to the power board.

[0056] As shown in Figure 3, a magnet 32 ​​is attached to the non-loaded end of the shaft 31 via a magnet holder 32A. The magnet 32 ​​is magnetized with half being the south pole and the other half being the north pole. Alternatively, the magnet 32 ​​may have alternating south and north poles on its outer surface when viewed in the circumferential direction.

[0057] The ECU 10 includes a first circuit board 60 (see Figure 7), a second circuit board 20 (see Figure 11), a second housing 11 (see Figure 3), a cover 40 (see Figure 3), a power wiring module 90 (see Figure 11), and a connector CNT (see Figure 3). The second housing 11 is made of a metal with high heat dissipation properties, such as aluminum or copper. The second housing 11 acts as a heat sink to dissipate the heat generated by the first circuit board 60 and the second circuit board 20. The cover 40 is made of a metal with high heat dissipation properties, such as aluminum or copper, and is joined to the second housing 11. As a result, even if heat generated by the first circuit board 60 and the second circuit board 20 is transferred from the second housing 11, it is efficiently dissipated to the outside through the cover 40.

[0058] As shown in Figure 3, a flange 39 is provided at the non-load end of the first housing 930 of the motor 30. The flange 39 has a female threaded portion 39H in the axial direction Ax. A flange 111 is provided at the load end of the second housing 11. The flange 111 has a through hole 111H in the axial direction Ax. A fixing member B1, such as a screw, passes through the through hole 111H and fastens to the female threaded portion 39H, thereby fixing the first housing 930 and the second housing 11.

[0059] As shown in Figure 3, a plurality of flanges 131 are provided on the non-loaded end of the second housing 11. The flanges 131 are provided with female threads in the axial direction Ax. A plurality of flanges 441 are provided on the outer edge of the cover 40. The flanges 4411 are provided with through holes 441H (see Figure 13) in the axial direction Ax, which will be described later. Fixing members B6 such as screws are fastened through the through holes 441H to the female threads, thereby fixing the cover 40 and the second housing 11.

[0060] As shown in Figure 7, the second housing 11 sandwiches the first circuit board 60 between itself and the support 70. The support 70 is made of a metal such as aluminum or copper, which has high heat dissipation properties, and is a heat sink with excellent heat dissipation capabilities. Two terminal blocks 80 are attached to the side of the support 70.

[0061] As shown in Figures 8 and 9A, the terminal block 80 includes a base 81, a mounting bracket 82, and a conductive terminal 83. The base 81 is made of an insulating material to ensure insulation between the terminals. One end of the conductive terminal 83 is inserted into the first circuit board 60 and electrically connected to the first circuit board 60.

[0062] The other end of the conductive terminal 83 is electrically connected to the mounting bracket 82. As shown in Figures 9A and 9B, the mounting bracket 82 has a through hole 82H through which a fixing member BM, such as a screw shown in Figure 9B, passes. The first motor coil wiring 321 or the second motor coil wiring 322 of the motor 30 has a through hole 32H. The first motor coil wiring 321 or the second motor coil wiring 322 is inserted into the insertion hole 81H of the base 81, and the fixing member BM passes through at the position where the through hole 82H and the through hole 32H are in communication, and fastens with a nut (not shown) on the back of the first motor coil wiring 321 or the second motor coil wiring 322. As a result, one terminal block 80 electrically connects the first circuit board 60 and the first motor coil wiring 321 of the motor 30, and the other terminal block 80 electrically connects the first circuit board 60 and the second motor coil wiring 322 of the motor 30. The mounting bracket 82 may be tightly fixed to the conductive terminal 83, or the mounting bracket 82 may be integrated with the conductive terminal 83 to form a single component.

[0063] The support 70 has a first top plate 71 and a second top plate 79 of different heights. The first top plate 71 and the second top plate 79 are of different sizes according to the heights of the capacitors 253 and 256 located between them and the first circuit board 60. A heat dissipation material is interposed between the capacitors 253 and 256 and the first top plate 71 and the second top plate 79, so that the heat from the capacitors 253 and 256 is transferred to the first top plate 71 and the second top plate 79, thereby suppressing the deterioration of the capacitors 253 and 256. The capacitors 253 and 256 are, for example, electrolytic capacitors.

[0064] As shown in Figure 8, the load side of the second housing 11 has a flat heat dissipation surface 112, a recess 113, and a protrusion 114. The second housing 11 has a first through hole 119 and a second through hole 118 that penetrate in the axial direction Ax. Part of the power wiring module 90 is inserted into the second through hole 118, and the first power terminal 93 reaches the first circuit board 60. The plug 62 of the board-to-board connector is inserted into the first through hole 119 and reaches the receptacle 61 (see Figure 11) of the second circuit board 20. This board-to-board connector transmits signals between the first circuit board 60 and the second circuit board 20. Furthermore, the board-to-board connector having the plug 62 and the receptacle 61 is called a floating connector and has a movable part that can absorb misalignment when the plug 62 and the receptacle 61 are mated together.

[0065] The protrusion 114 has a female threaded portion 114H that is drilled in the axial direction Ax from the upper surface on the load side. Of the multiple protrusions 114, some of the protrusions 114 face the support 70 within the notch 60N of the first circuit board 60. Other protrusions 114 face the through hole 60H2 of the first circuit board 60 shown in Figure 9A. The support 70 has a through hole 72H that penetrates in the axial direction Ax. A fixing member B2 such as a screw passes through the through hole 72H, the notch 60N of the first circuit board 60, or the through hole 60H2 and is fastened to the female threaded portion 114H.

[0066] As shown in Figure 9A, the support 70 has a base 72 and a first top plate 71 that protrudes from the base 72 toward the load side. The support 70 also has two first sides 74 and two second sides 75. The first sides 74 and the second sides 75 connect the base 72 and the first top plate 71, respectively. The support 70 has two second top plates 79 that extend in a second direction away from the two second sides 75, respectively.

[0067] A through-hole 76 is provided in the first top plate 71 of the support 70, extending axially Ax. A magnet 32 ​​(see Figure 3), located at the non-load end of the shaft 31, is inserted into the through-hole 76. As a result, the magnet 32 ​​is positioned near the rotation angle sensor 23a mounted on the first circuit board 60. A through-hole 77 is also provided on the side of the support 70. When the terminal block 80 is attached to the support 70, the through-hole 77 is closed. The support 70 is made lighter by the size of the through-hole 77.

[0068] The support body 70 shown in Figure 10 is provided with four female threaded portions 78 that open on the non-load side. When a fixing member B3 such as a screw passes through the through hole 60H1 of the first circuit board 60 and is fastened to the female threaded portion 78, the support body 70 and the first circuit board 60 are fixed in close contact, as shown in Figure 10. It is desirable that the female threaded portions 78 that open on the non-load side and are located diagonally opposite each other are point-symmetrical. This makes it easier to assemble the support body 70 and the first circuit board 60.

[0069] As shown in Figures 9A and 10, the first circuit board 60 has a plurality of electronic components mounted on both sides of the board body. The board body of the first circuit board 60 is a printed circuit board formed of, for example, resin. The plurality of electronic components mounted on a single board body include field-effect transistors (FETs), magnetic sensors, electrolytic capacitors, resistors, diodes, thermistors, application-specific integrated circuits (ASICs), etc. These plurality of electronic components constitute the detection circuit 23, the first power circuit 25A, and the second power circuit 25B shown in Figure 6.

[0070] As shown in Figure 9A, capacitors 253 and 256 are mounted on the first surface 60A of the first circuit board 60. As shown in Figure 8, when the support 70 is attached to the first circuit board 60, the capacitors 253 and 256 are covered by the support 70.

[0071] As shown in Figure 9A, a rotation angle sensor 23a is mounted on the first surface 60A of the first circuit board 60. The rotation angle sensor 23a is, for example, a spin valve sensor. A spin valve sensor is an element that has a non-magnetic layer sandwiched between a pin layer of a ferromagnetic material whose magnetization direction is fixed by an antiferromagnetic layer, etc., and a free layer of a ferromagnetic material, and is a sensor that can detect changes in the direction of magnetic flux. Spin valve sensors include GMR (Giant Magneto Resistance) sensors and TMR (Tunnel Magneto Resistance) sensors. Note that the rotation angle sensor 23a can be any sensor that can detect the rotation of the magnet 32. The rotation angle sensor 23a may be, for example, an AMR (Anisotropic Magneto Resistance) sensor or a Hall sensor.

[0072] As shown in Figure 9A, the second surface 60B of the first circuit board 60 contains heat-generating electronic components, namely a field-effect transistor TR and a shunt resistor SR. The field-effect transistor TR is provided not only on the switching element 252 shown in Figure 6, but also on the current interruption circuit 255, the interruption drive circuit 243, and on the wiring that supplies the power supply voltage Vdc. As shown in Figure 6, the shunt resistor SR is connected to the current detection circuit 254.

[0073] The field-effect transistor TR is in contact with the heat dissipation surface 112 of the second housing 11 shown in Figure 8 via a heat dissipation material called TIM (Thermal Interface Material). The heat dissipation material is, for example, a material made by mixing a thermally conductive filler with a silicone polymer, and any material other than the above material may be used as long as it has a higher thermal conductivity than the main body of the first circuit board 60. The shunt resistor SR is placed in the recess 113 of the second housing 11 shown in Figure 8. The heat dissipation material is located inside the recess 113.

[0074] As shown in Figure 9A, legs 84 extend from both sides of the base 81 of the terminal block 80 toward the support 70, and through holes 85H are made at the ends 85 of the legs 84. Fixing members B4 such as screws are fastened through the through holes 85H to the female threaded portion 73H on the contact surface 73 of the first side surface 74.

[0075] Here, the contact surface 73 of the first side surface 74 shown in Figure 9A and the contact surface of the fixing member BM of the mounting bracket 82 shown in Figure 9B are parallel. Therefore, even if the terminal block 80 is pressed by a fixing member BM such as a screw, the stress associated with the pressing is absorbed by the contact surface 73 of the first side surface 74 via the end portion 85 of the leg portion 84. As a result, deformation of the conductive terminal 83 and stress applied to the first circuit board 60 are suppressed.

[0076] As described above, the ECU 10 includes a first circuit board 60, a second housing 11, a support 70 which serves as a heat sink, and a terminal block 80. The first circuit board 60 is equipped with a field-effect transistor TR that outputs a current to excite the first motor coil 37 or the second motor coil 38, and a rotation angle sensor 31a positioned on the extension of the axial direction Ax of the shaft 31. The second housing 11 is provided on the non-load side of the first circuit board 60. The support 70 is provided on the load side of the first circuit board 60 and sandwiches the first circuit board 60 between itself and the second housing 11. The terminal block 80 is fixed to the contact surface 73 of the first side surface 74 of the support 70 which serves as a heat sink, and electrically connects the first motor coil wiring 321 or the second motor coil wiring 322 to the first circuit board 60.

[0077] As a result, the first circuit board 60 is sandwiched in the axial direction Ax between the second housing 11 and the support body 70, which is a heat sink. Therefore, the size of the axial direction Ax parallel to the motor shaft 31 is suppressed, and the electric drive unit 1 becomes smaller. The terminal block 80 is fixed and supported on the contact surface 73 of the first side surface 74 of the support body 70. Therefore, even if the terminal block 80 is pressed by a fixing member BM such as a screw, the stress associated with the pressing is applied to the support body 70, and the stress applied to the first circuit board 60 is reduced. As a result, the lifespan of the first circuit board 60 is extended and the reliability of the electric drive unit 1 is improved.

[0078] The first housing 930 has a tool insertion hole 36H. The motor 30 covers the tool insertion hole 36H and is equipped with a side cover 36 that can be attached to and removed from the first housing 930. This makes it easy to connect or disconnect the motor 30 and the ECU 10 electrically by attaching or removing the side cover 36.

[0079] The first circuit board 60 has a field-effect transistor TR mounted on its second surface 60B, which faces the second housing 11, and electrolytic capacitors 253 and 256 mounted on its first surface 60A, which faces the support 70. This allows both sides of the first circuit board 60 to be used effectively, and also allows for a smaller radial size of the first circuit board 60.

[0080] The support 70 has a first top plate 71 that covers the capacitor 253, and a magnet 32 ​​is inserted into an axial through hole 76 opened in the top plate at a position that does not overlap with the capacitor 253. This promotes the cooling of the capacitor 253 by heat conduction to the first top plate 71. Furthermore, the first side surface 74 of the support 70, which is created by the axial Ax of the capacitor 253, can be used as a contact surface 73 with the terminal block 80. In addition, even at the position that does not overlap with the capacitor 253, the space radially outside the magnet 32 ​​can be used as a placement area for the capacitor 253 by inserting the magnet 32. As a result, the axial Ax of the electric drive unit 1 is reduced.

[0081] There is a step between the first top plate 71 and the second top plate 79. As a result, the support 70 becomes a heat sink with a minimum volume corresponding to the size of each capacitor 253, 256, contributing to the weight reduction of the electric drive unit 1.

[0082] As shown in Figure 11, the ECU 10 has a second circuit board 20 which has control circuits 24 that control a first power circuit 25A and a second power circuit 25B, each having a field-effect transistor TR. The second circuit board 20 is located on the non-load side of the second housing 11. The first circuit board 60 and the second circuit board 20 are electrically connected by an inter-board connector inserted into a first through-hole 119 in the axial direction Ax that is opened in the second housing 11. As a result, both axial sides of the second housing 11 are used as heat dissipation surfaces, and the second housing acts as a heat sink.

[0083] The second circuit board 20 is housed in a housing space 11R provided in the second housing 11. This reduces the axial length Ax of the electric drive unit 1.

[0084] The motor stator 931 includes a first motor coil wiring 321 connected to a first coil group Gr1 and a second motor coil wiring 322 connected to a second coil group Gr2. There are two terminal blocks 80, and one terminal block 80 and the other terminal block 80 are positioned on either side of the support 70. Here, one terminal block 80 electrically connects the first motor coil wiring 321 to the first circuit board 60, and the other terminal block 80 electrically connects the second motor coil wiring 322 to the first circuit board 60. As a result, even if the motor coil wiring is redundant, the radial size of the motor 30 is suppressed by utilizing multiple sides of the support 70.

[0085] The second housing 11 and the support body 70 are connected by fixing members B2 such as screws. As a result, even if the terminal block 80 is pressed by fixing members BM such as screws, the stress associated with the pressing is transmitted to the support body 70, fixing members B2, and the second housing 11. Consequently, the stress on the first circuit board 60 is further reduced.

[0086] Figure 11 is an exploded perspective view showing an example of a configuration in which the control board according to Embodiment 1 is attached to a wiring module. Figure 12A is a top perspective view of the heat sink according to Embodiment 1. Figure 12B is an explanatory diagram for explaining the positional relationship between the heat dissipation surface of the heat sink according to Embodiment 1 and the second circuit board. Figure 12C is a top perspective view of the second circuit board according to Embodiment 1.

[0087] As shown in Figure 11, the second circuit board 20 has multiple electronic components mounted on both sides of the board body. The board body of the second circuit board 20 is a printed circuit board formed of, for example, resin. The multiple electronic components mounted on one board body include, for example, a central processing unit (CPU), an application-specific integrated circuit (ASIC), a power management integrated circuit, capacitors, resistors, diodes, thermistors, and receptacles 61. These multiple electronic components constitute the control circuit 24 shown in Figure 6.

[0088] The second circuit board 20 has through holes CNTIN1, CNTIN3, and PWCH.

[0089] As shown in Figure 11, a heat sink 29 is placed between the power wiring module 90 and the second circuit board 20. The heat sink 29 is made of a metal such as aluminum or copper, which has high heat dissipation properties, and can dissipate heat from the second circuit board 20, the choke coil 91, and the capacitor 92.

[0090] As shown in Figure 11, the heat sink 29 has a first base surface 291 on the second circuit board 20 side, a projection 292 protruding from the first base surface 291 toward the second circuit board, a heat dissipation surface 293, and a heat dissipation surface 294. The heat sink 29 has a through hole 29H that penetrates axially. The terminals of the connector CNT2 are placed inside the through hole 29H. This prevents the terminals of the connector CNT2 from contacting the heat sink 29 and causing a short circuit.

[0091] The projection 292 has a frustoconical shape. The projection 292 protrudes toward the second circuit board 20 side more than the heat dissipation surfaces 293 and 294.

[0092] As shown in Figure 12A, the heat sink 29 has a second base surface 295 on the power wiring module 90 side, and recesses 296 and 297 that are recessed from the second base surface 295 toward the second circuit board side.

[0093] As shown in Figure 11, the power wiring module 90 connects power wiring PW (see Figure 2), which transmits power from a power supply 183 connected to connector CNT2 (see Figure 16), to lead frame wiring within the module, and transmits it to the first circuit board 60 and the second circuit board 20. The lead frame wiring is made of, for example, a copper alloy. A choke coil 91 and a capacitor 92 are attached to the power wiring module 90 to remove high-frequency components from the power wiring PW from the power supply 183. The resin of the power wiring module 90 is, for example, polybutylene terephthalate (PBT). The board-to-board connector allows for displacement of the position of the plug 62 relative to the receptacle 61, but is assembled in a way that suppresses variations in the position of the plug 62 relative to the receptacle 61.

[0094] The greater the power required to drive the motor, the larger the power wiring on the circuit board needs to be, which increases the overall area of ​​the board. Therefore, it is desirable to reduce the amount of power wiring on the circuit board. Because there is lead frame wiring in the power wiring module 90, the area of ​​the power wiring on the first circuit board 60 is reduced. As a result, the area of ​​the first circuit board 60 is reduced, and the radial size of the ECU 10 is reduced.

[0095] On the load side of the cover 40, the input / output terminals of connector CNT1, the power input terminals PWCH1 and PWCH2 of connector CNT2, and the input / output terminals of connector CNT3 penetrate the cover 40 axially and protrude from the main body of the cover 40.

[0096] The input and output terminals of connector CNT1 pass outside the power wiring module 90 and the heat sink 29, and are inserted into the through-hole CNTIN1 of the second circuit board 20, where they are electrically connected. Similarly, the input and output terminals of connector CNT3 pass outside the power wiring module 90 and the heat sink 29, and are inserted into the through-hole CNTIN1 of the second circuit board 20, where they are electrically connected.

[0097] As shown in Figure 11, the power wiring module 90 includes a first power terminal 93 and a second power terminal 96 that protrude from the first surface 90A. In the power wiring module 90, the resin of the base 97 of the first power terminal 93 and the second power terminal 96 is thicker than the surrounding area of ​​the base 97. This makes the first power terminal 93 and the second power terminal 96 less likely to tilt in the axial direction.

[0098] As shown in Figure 11, through-holes INH for power input are drilled in the resin in the space adjacent to the power input sections PWin1 and PWin2 of the lead frame wiring. When the power wiring module 90 is attached to the cover 40, the power input terminals PWCH1 and PWCH2 are inserted into the through-holes INH. Power input section PWin1 and power input terminal PWCH1 are electrically connected using a low-melting-point metal such as solder or welding, and power input section PWin2 and power input terminal PWCH1 are electrically connected using a low-melting-point metal such as solder or welding. This ensures insulation and suppresses the thickness in the axial direction Ax, while electrically connecting the connector CNT2 and the power wiring module 90.

[0099] When the two positioning protrusions 95PU of the power wiring module 90 are inserted into the two through holes 299H of the heatsink 29, the position of the heatsink 29 relative to the power wiring module 90 is determined. The mounting portion 298 abuts against the support protrusion 424, and the through hole 298H and the female thread portion 424H of the support protrusion 424 are aligned in a straight line. When a fixing member such as a bolt is fastened to the female thread portion 424H of the support protrusion 424 (see Figure 14), the cover 40 and the heatsink 29 are fixed together. Inside the through hole 29H, power input terminals PWCH1 and PWCH2, and power input sections PWin1 and PWin2 are arranged to prevent short circuits between the heatsink 29 and the power wiring.

[0100] The second circuit board 20 is attached to the power wiring module 90. The second power terminal 96 is inserted into the through-hole PWCH and electrically connected. The input and output terminals of connector CNT1 are inserted into the through-hole CNTIN1 of the second circuit board 20 and electrically connected. Similarly, the input and output terminals of connector CNT3 are inserted into the through-hole CNTIN1 of the second circuit board 20 and electrically connected.

[0101] The second circuit board 20 is supported by contacting the support projection 423 (see Figure 14). A fixing member such as a bolt penetrates the second circuit board 20 and is fastened to a female threaded portion provided at the top of the support projection 423 (see Figure 14).

[0102] The first power terminal 93 shown in Figure 11 is longer than the second power terminal 96. This allows power to be supplied from the power wiring module 90 to both the first circuit board 60 and the second circuit board 20, which are located at different positions in the axial direction Ax.

[0103] A recessed positioning hole 421H and support protrusions 422, 423, and 424 protruding towards the load are positioned on the load-side reference surface 490 of the cover 40. The positioning protrusions (not shown) of the power wiring module 90 are inserted into the positioning hole 421H, determining the position of the power wiring module 90 relative to the cover 40. As shown in Figure 11, a cylindrical body 94 covering the support protrusions 422 is integrally molded into the power wiring module 90. A through hole is drilled in the center of the cylindrical body 94, and there is a hollow space inside the cylindrical body. The support protrusions 422 are inserted into the hollow spaces inside the three cylindrical bodies 94.

[0104] The underside of the cover 40 has a reference surface 490 on the load side of the cover 40. A choke coil 91 is inserted into a recess 491 that is recessed from the reference surface 490. The bottom surface of the recess 491 serves as a heat dissipation surface for the choke coil 91 and one capacitor 92 via a heat dissipation material called TIM (Thermal Interface Material).

[0105] As shown in Figures 11 and 12A, the second base surface 295 is the surface opposite the first base surface 291 in the axial direction. A choke coil 91 and one capacitor 92 are inserted into the recess 296. The bottom surface of the recess 296 serves as a heat dissipation surface for the choke coil 91 and one capacitor 92 via a heat dissipation material called TIM (Thermal Interface Material). Two capacitors 92 are inserted into the recess 297. The bottom surface of the recess 297 serves as a heat dissipation surface for the two capacitors 92 via a heat dissipation material called TIM (Thermal Interface Material). This promotes the cooling of the noise-reducing choke coil 91 by the heat sink 29 and reduces the axial size of the electronic control unit.

[0106] As described above, the heat sink has a first recess 296, and the cover 40 has a second recess 491. The first surface of the choke coil 91 protrudes from the first surface 90A of the power wiring module 90 and is inserted into the first recess 296. The second surface of the choke coil 91 protrudes from the second surface 90B, which is opposite to the first surface 90A, and is inserted into the second recess 491. This improves the heat dissipation of both sides of the choke coil 91.

[0107] As shown in Figures 12B and 12C, the second circuit board 20 is mounted with an integrated circuit 24IC1 and a power control integrated circuit IC24IC2. The heat dissipation surface 293 is positioned to overlap with the integrated circuit 24IC1 in the axial direction. The heat dissipation surface 294 is positioned to overlap with the integrated circuit 24IC4 in the axial direction. This allows the heat generated by the integrated circuits 24IC1 and IC24IC2 to be efficiently transferred to the heat sink 29. The integrated circuit 24IC1 and the power control integrated circuit IC24IC2 constitute the control calculation unit 241 (control circuit 24) shown in Figure 6. The reason there are two of each integrated circuit 24IC1 and power control integrated circuit IC24IC2 is that, as shown in Figure 6, there are two independent control calculation units 241. Even if one control calculation unit 241 fails to operate, the other control calculation unit 241 will continue to function, thus increasing the continuity of operation.

[0108] As shown in Figure 12C, the second circuit board 20 has a recess 20H that is sized to accommodate the projection 292 of the heat sink 29, located opposite the projection 292.

[0109] Figure 13 is a perspective view showing the top surface of the cover and connector according to Embodiment 1. Figure 14 is a perspective view showing the back surface of the cover according to Embodiment 1. Figure 15 is a cross-sectional view showing the cross-section of the electric drive device according to Embodiment 1. Figure 16 is a perspective view showing the back surface of the connector according to Embodiment 1.

[0110] As shown in Figure 13, the connector CNT is divided into connector CNT1, connector CNT2, and connector CNT3 according to their function. Connectors CNT1, CNT2, and CNT3 are attached to the cover 40 via sealing members CNO1, CNO2, and CNO3, respectively, such as O-rings. Sealing members CNO1, CNO2, and CNO3 are so-called O-rings made of rubber or elastomer. Sealing members CNO1, CNO2, and CNO3 are sometimes collectively referred to as sealing member CNO. Connectors CNT1, CNT2, and CNT3 each have a connector hole CNTH that penetrates in the axial direction Ax. Connectors CNT1, CNT2, and CNT3 each have a socket portion 49 for receiving a harness plug.

[0111] The cover 40 has a first surface 44 on the non-load side and a connector base portion that protrudes from the first surface 44 toward the non-load side. The connector base portion has a second surface 45 formed by a part of the cover 40 rising from the first surface 44, and a side surface 451 between the first surface 44 and the second surface 45. In Embodiment 1, there are three connector bases, corresponding to the shapes of connector CNT1, connector CNT2, and connector CNT3.

[0112] Multiple female threaded portions 45H are provided on the second surface 45. Fixing members B5, such as bolts, pass through the connector holes CNTH and are fastened to the female threaded portions 45H. As a result, connectors CNT1, CNT2, and CNT3 are each fixed to the cover 40. The connector terminals 484 (see Figure 16) of connectors CNT1, CNT2, and CNT3 pass through through holes 41H, 42H, and 43H, respectively, which are drilled in the axial direction Ax in the cover 40, and reach the opposite side of the cover 40. The through holes 41H, 42H, and 43H are provided on the second surface 45 of the connector base and penetrate from the second surface 45 to the back surface of the cover 40.

[0113] The power wiring module 90 is fastened and secured to the back surface of the cover 40 with fastening members such as bolts. The second circuit board 20 is fastened and secured to the cover 40 with fastening members such as bolts. The heat sink 29 is fastened and secured to the cover 40 with fastening members such as bolts. As a result, the power wiring module 90, the heat sink 29, and the second circuit board 20 are combined via the cover 40 to form the upper assembly.

[0114] As shown in Figure 11, the integrated circuits 24IC1 and 24IC2 shown in Figure 12C face the first base surface 291, while the noise-reducing choke coil 91 and capacitor 92 of the power wiring module 90 face the second base surface 295. As a result, the heat generated by the integrated circuits 24IC1 and 24IC2 is transferred to the heat sink 29, suppressing the temperature rise of the integrated circuits 24IC1 and 24IC2. In addition, the heat generated by the noise-reducing choke coil 91 and capacitor 92 is also transferred to the heat sink 29.

[0115] The second circuit board 20, the heat sink 29, and the power wiring module 90 are assembled to the cover 40. Viewed in the axial direction, the second circuit board 20, the heat sink 29, and the power wiring module 90 are sized to fit inside the outer shape of the cover 40. When the cover 40 is assembled to close the housing space 11R (see Figure 15) of the second housing 11, the second circuit board 20, the heat sink 29, and the power wiring module 90 are housed in the housing space 11R.

[0116] The second housing 11 has a bottom portion 115 and a side wall portion 116 surrounding the bottom portion 115. Inside the side wall portion 116 is a housing space 11R. The housing space 11R of the second housing 11 is sealed by the lid 40 covering the housing space 11R of the second housing 11 via the sealing member CNO (Figure 13) described above.

[0117] As shown in Figure 15, the non-load side end of the second housing 11 and the load side end of the lid 40 are sealed via a sealing member OR2 (second sealing member). The sealing member OR2 is a so-called O-ring made of rubber or elastomer.

[0118] Similarly, the inner circumferential surface of the first housing 930 and the outer circumferential surface of the second housing 11 are sealed via a sealing member OR1 (first sealing member). The sealing member OR1 is a so-called O-ring made of rubber or elastomer.

[0119] The sealing members OR1, OR2, and ONO enhance the airtightness of the electric drive unit. Increased airtightness makes it more difficult for heat from the electronic components of the first circuit board 60 and the second circuit board 20 to escape, thus necessitating the suppression of temperature rise within the electric drive unit.

[0120] A second circuit board 20 and a power wiring module 90 are mounted on one side of the cover 40 on the load side, and a connector CNT is mounted on the other side of the cover 40 on the non-load side. When the cover 40 is attached to the second housing 11, the second circuit board 20 and the power wiring module 90 are housed in the accommodation space 11R of the second housing 11. This reduces the axial Ax size of the ECU 10.

[0121] As shown in Figure 15, the input / output terminals for inputting and outputting data from the torque sensor 194 (see Figure 2) connected to connector CNT1 are connected directly to the second circuit board 20 without going through the power wiring module 90. Similarly, the communication terminals for CAN communication connected to connector CNT3 are also connected directly to the second circuit board 20 without going through the power wiring module 90.

[0122] As shown in Figure 16, sealing members CNO1, CNO2, and CNO3 are arranged on the outer circumference of the sealing support portion 483. The sealing support portion 483 protrudes on the load side from the back surface 482 of the base portion and has a cylindrical shape. The outer diameter of the sealing support portion 483 is larger than the inner diameter of the sealing member CNO2. The sealing support portion 483 is arranged around the connector terminal 484. This improves the accuracy of resin molding and stabilizes the shape of the sealing support portion 483. As a result, the airtightness of the seal housing space is improved.

[0123] As shown in Figure 16, the two positioning protrusions 46 protrude towards the load side from the back surface 482 of the base. As shown in Figure 13, two recesses 46H are provided on the second surface 45. When the positioning protrusions 46 are inserted into the recesses 46H, the temporary position of the connector CNT2 relative to the connector base is determined. Then, the fixing members B5 pass through the connector holes CNTH and are fastened to the female threaded portions 45H.

[0124] Figure 17 is an exploded cross-sectional view of the cover and connector according to Embodiment 1. Figure 18 is a cross-sectional view of the assembled cover and connector according to Embodiment 1. The connector CNT2 has a base portion 48, a socket portion 49 protruding from the base portion 48 toward the non-load side, a connector terminal 484 inserted into a through hole 42H, and a sealing member CNO2. The base portion 48 has a canopy portion 481 whose outer edge protrudes toward the load side than the back surface 482 of the base portion 48, surrounds the outer edge of the connector base portion, and covers a part of the side surface 451 of the connector base portion, and a sealing support portion 483. The sealing support portion 483 is arranged around the connector terminal 484. In Figure 17, the power input terminal PWCH1 and the power input terminal PWCH2 are exposed from the tip of the connector terminal 484.

[0125] The through hole 42H has a first inner wall 452 having a first diameter L31, a second inner wall 454 having a second diameter L32 smaller than the first diameter L31, and a first bottom 453 between the first inner wall 452 and the second inner wall 454. The through hole 42H further has a third inner wall 456 having a third diameter L33 smaller than the second diameter L32, and a second bottom 455 between the second inner wall 454 and the third inner wall 456.

[0126] The diameter of the sealing support portion 483 is equal to the second diameter L32. The maximum width L34 of the connector terminal 484 is smaller than the second diameter L32, and there is a gap 489 between the sealing support portion 483 and the connector terminal 484. The sealing member CNO2 has a diameter φ.

[0127] As shown in Figure 18, the sealing member CNO2 is inserted into the through hole 42H together with the connector terminal 484. The sealing member CNO2 is sandwiched between the first inner wall 452 of the through hole 42H and the side surface 483S of the sealing support portion 483.

[0128] The diameter φ of the sealing member CNO2 is greater than the distance L22 between the first inner wall 452 of the through hole 42H and the sealing support portion 483. Therefore, although the sealing member CNO2 deforms in the axial direction Ax, it does not become greater than the distance L21 between the back surface of the base portion 48 and the first bottom portion 453. As a result, the sealing member CNO2 is housed in the seal housing space surrounded by the back surface 482 of the base portion 48, the first inner wall 452, the first bottom portion 453, and the side surface 483S of the sealing support portion 483, and at least one of gaps G1 and G2 is created in the axial direction Ax of the sealing member CNO2. As a result, the deformation of the sealing member CNO2 does not widen the gap between the back surface 482 of the base portion 48 and the second surface 45 of the lid 40, and the contact surface between the back surface 482 of the base portion 48 and the second surface 45 of the lid 40 can be maintained.

[0129] The side surface 483S of the sealing support portion 483 is in contact with the second inner wall 454. As a result, even if grease that suppresses deterioration of the sealing member CNO2 is sealed inside the seal housing space, the grease is less likely to leak out. The load-side end portion 483P of the sealing support portion 483 is not in contact with the second bottom portion 455. Therefore, a distance L23 is created between the end portion 483P of the sealing support portion 483 and the second bottom portion 455. The distance L23 is, for example, about 2 mm.

[0130] Even if high-pressure water attempts to enter from the outside, the eaves portion 481 prevents water from entering. Even if water penetrates beyond the eaves portion 481, the sealing member CNO2 sandwiched between the first inner wall 452 of the through hole 42H and the sealing support portion 483 prevents water from entering. As a result, the waterproof level of the electric drive device 1 is improved, and sufficient waterproofing can be maintained even under high water pressure.

[0131] The back surface 482 of the base 48 and the second surface 45 of the cover 40 are in close contact. The second surface 45 of the cover 40 is a milled surface, and its surface roughness is small. The gap between the back surface 482 of the base 48 and the second surface 45 of the cover 40 is smaller than the distance L11 mentioned above. As a result, even if water penetrates beyond the overhang 481, the contact surface between the back surface 482 of the base 48 and the second surface 45 of the cover 40 suppresses the intrusion of water.

[0132] As shown in Figure 18, the load-side end 481P of the canopy portion 481 protrudes towards the first surface 44 side from the mating surface SS between the back surface 482 of the base portion 48 and the second surface 45 of the cover 40.

[0133] The distance L11 between the load-side end 481P of the canopy portion 481 and the first surface 44 of the cover 40 is narrower than the distance between the inner wall 481S of the canopy portion 481 and the side surface 451 of the connector base portion. The distance L11 is, for example, 1 mm or more and 1.5 mm or less. The distance L12 between the canopy portion 481 and the side surface 451 of the connector base portion is greater than the distance L11 between the canopy portion 481 and the first surface 44 of the cover 40. For example, the distance L12 is 2 mm or more and 3 mm or less. Furthermore, the space between the canopy portion 481 and the side surface 451 of the connector base portion is greater than the space between the canopy portion 481 and the first surface 44 of the cover 40. As a result, even if water penetrates beyond the eaves portion 481, the space between the eaves portion 481 and the side surface 451 of the connector base portion is larger than the space between the eaves portion 481 and the first surface 44 of the cover 40, making it difficult for water to reach the area between the back surface 482 of the cover 40 and the second surface 45 of the cover 40. Consequently, the waterproof level of the electric drive device 1 is improved, and sufficient waterproofing can be maintained even under high water pressure.

[0134] The structure of connector CNT2 has been described above. Connectors CNT1 and CNT3 have similar structures, so their structures will not be described. The same applies to Embodiments 2 and 3, which will be described later.

[0135] Figure 19 is a circuit diagram showing the equivalent circuit of the power wiring module of the embodiment. As shown in Figures 19A and 19, power is received from different power inputs PWin1 and PWin2 by independent first power supply circuit 90R and second power supply circuit 90L, respectively. The circuits for the choke coil 91 and capacitor 92 are also separate for the first power supply circuit 90R and the second power supply circuit 90L. The noise-degraded electrodes then branch within the power wiring module 90 to a first power supply terminal 93 that supplies power to the first circuit board 60 and a second power supply terminal 96 that supplies power to the second circuit board 20.

[0136] The first power terminal 93 of the first power supply circuit 90R is connected to the first power circuit 25A (see Figure 6). The first power terminal 93 of the second power supply circuit 90L is connected to the second power circuit 25B (see Figure 6).

[0137] The second power terminal 96 of the first power supply circuit 90R is connected to one of the control calculation units 241 (see Figure 6). The first power terminal 93 of the second power supply circuit 90L is connected to the other control calculation unit 241 (see Figure 6).

[0138] Thus, the electric drive device 1 of this embodiment independently receives power from two systems and drives them in two separate systems, the first coil group gr1 and the second coil group Gr2, thereby improving functional continuity.

[0139] The heat sink support 70 has an outer shape that fits inside the sealing member OR1 when viewed in the axial direction. This allows the support 70 to be housed inside the first housing 930. The heat sink 29 has an outer shape that fits inside the sealing member OR2 when viewed in the axial direction. This allows the heat sink 29 to be housed inside the second housing 11. As a result, the electric drive unit can be miniaturized while suppressing the temperature rise inside the electric drive unit.

[0140] Here, the support 70 and heat sink 29 have a volume limit because they are housed inside either the first housing 930 or the second housing 11. Therefore, the volume of the second housing 11 (heat sink) is made larger than the volume of the support 70 (heat sink) to increase the heat capacity of the second housing 11 (heat sink). The support 70 is fixed to the second housing 11 (heat sink) by a metal fixing member B2 (first fixing member). Electronic components can be mounted on both sides of the first circuit board 60 and the second circuit board 20. As shown in Figure 21, heat from electronic components mounted on one side of the first circuit board 60 is transferred to the second housing 11 (heat sink) via a heat path through the support 70 and the fixing member. As a result, the support 70 is less likely to become thermally saturated. Heat from electronic components mounted on the other side of the first circuit board 60 is transferred to the second housing 11 (heat sink).

[0141] As shown in Figure 22, the heat from the noise-reducing choke coil 91 and capacitor 92 of the power wiring module 90 is dissipated through a heat path to the heat sink 29 and a heat path to the cover 40. Heat from one electronic component on the second circuit board 20 is transferred to the heat path to the heat sink 29, and heat from the other electronic component on the second circuit board 20 is transferred to the heat path to the second housing 11.

[0142] Furthermore, the volume of the lid 40 is made larger than the volume of the heat sink 29, thereby increasing the heat capacity of the lid 40. As shown in Figure 23, the heat from the heat sink 29 is transferred to the lid 40 via a heat path through the metal fixing member B8 (second fixing member). As a result, the heat sink 29 is less likely to become thermally saturated.

[0143] As described above, the electric drive device 1 according to Embodiment 1 comprises a motor 30 and an ECU 10 provided on the non-load side of the shaft 31 for driving and controlling the motor 30. The motor 30 has a shaft 31, a motor rotor 932, a motor stator 931, and a first housing 930. The shaft 31 extends axially Ax from the load side to the non-load side. The rotation of the motor rotor 932 is linked to the rotation of the shaft 31. The motor stator 931 has a first motor coil 37 and a second motor coil 38, and first motor coil wiring 321 and second motor coil wiring 322 for supplying power to the first motor coil 37 and the second motor coil 38, respectively, and rotates the motor rotor 932. The first housing 930 houses the motor rotor 932 and the motor stator 931 inside. A magnet 32 ​​is provided on the non-load side of the shaft 31 for driving and controlling the motor 30.

[0144] The ECU 10 includes a first circuit board 60, a second housing 11, a support 70 which serves as a second heat sink, and a terminal block 80. The first circuit board 60 is equipped with a field-effect transistor TR that outputs a current to excite the first motor coil 37 or the second motor coil 38, and a rotation angle sensor 31a positioned on the extension of the axial direction Ax of the shaft 31. The second housing 11 is provided on the non-load side of the first circuit board 60. The support 70 is provided on the load side of the first circuit board 60 and sandwiches the first circuit board 60 between itself and the second housing 11. The terminal block 80 is fixed to the contact surface 73 of the first side surface 74 of the support 70 which serves as the second heat sink, and electrically connects the first motor coil wiring 321 or the second motor coil wiring 322 to the first circuit board 60.

[0145] As a result, the first circuit board 60 is sandwiched in the axial direction Ax between the second housing 11 and the support 70, which is the second heat sink. Therefore, the size of the axial direction Ax parallel to the shaft 31 of the motor 30 is suppressed, and the electric drive unit 1 becomes smaller. The terminal block 80 is fixed and supported on the contact surface 73 of the first side surface 74 of the support 70. Therefore, even if the terminal block 80 is pressed by a fixing member BM such as a screw, the stress associated with the pressing is applied to the support 70, and the stress applied to the first circuit board 60 is reduced. As a result, the lifespan of the first circuit board 60 is extended and the reliability of the electric drive unit 1 is improved.

[0146] The first housing 930 has a tool insertion hole 36H. The motor 30 covers the tool insertion hole 36H and is equipped with a side cover 36 that can be attached to and removed from the first housing 930. This makes it easy to connect or disconnect the motor 30 and the ECU 10 electrically by attaching or removing the side cover 36.

[0147] The first circuit board 60 has a field-effect transistor TR mounted on its second surface 60B, which faces the second housing 11, and electrolytic capacitors 253 and 256 mounted on its first surface 60A, which faces the support 70. This allows both sides of the first circuit board 60 to be used effectively, and also allows for a smaller radial size of the first circuit board 60.

[0148] The support 70 has a first top plate 71 that covers the capacitor 253, and a magnet 32 ​​is inserted into an axial through hole 76 opened in the top plate at a position that does not overlap with the capacitor 253. This promotes the cooling of the capacitor 253 by heat conduction to the first top plate 71. Furthermore, the first side surface 74 of the support 70, which is created by the axial Ax of the capacitor 253, can be used as a contact surface 73 with the terminal block 80. In addition, even at the position that does not overlap with the capacitor 253, the space radially outside the magnet 32 ​​can be used as a placement area for the capacitor 253 by inserting the magnet 32. As a result, the axial Ax of the electric drive unit 1 is reduced.

[0149] There is a step between the first top plate 71 and the second top plate 79. As a result, the support 70 becomes a heat sink with a minimum volume corresponding to the size of each capacitor 253, 256, contributing to the weight reduction of the electric drive unit 1.

[0150] The second circuit board 20 has control circuits 24 that control the first power circuit 25A and the second power circuit 25B, each having a field-effect transistor TR. The second circuit board 20 is located on the non-load side of the second housing 11, and the first circuit board 60 and the second circuit board 20 are electrically connected by an inter-board connector inserted into a first through-hole 119 in the axial direction Ax that is opened in the second housing 11. This allows both axial sides of the second housing 11 to be used as heat dissipation surfaces.

[0151] The second circuit board 20 is housed in a recessed space 11R provided in the second housing 11. This reduces the axial length Ax of the electric drive unit 1.

[0152] The motor stator 931 includes a first motor coil wiring 321 connected to a first coil group Gr1 and a second motor coil wiring 322 connected to a second coil group Gr2. There are two terminal blocks 80, and one terminal block 80 and the other terminal block 80 are positioned on either side of the support 70. Here, one terminal block 80 electrically connects the first motor coil wiring 321 to the first circuit board 60, and the other terminal block 80 electrically connects the second motor coil wiring 322 to the first circuit board 60. As a result, even if the coil wiring is redundant, the radial size of the motor 30 is suppressed by utilizing multiple sides of the support 70.

[0153] The second housing 11 and the support body 70 are connected by fixing members B2 such as screws. As a result, even if the terminal block 80 is pressed by fixing members BM such as screws, the stress associated with the pressing is transmitted to the support body 70, fixing members B2, and the second housing 11. Consequently, the stress on the first circuit board 60 is further reduced.

[0154] The ECU 10 includes a first circuit board 60, a second circuit board 20, a second housing 11 that houses the second circuit board 20 and has a first through-hole 119 penetrating in the axial direction Ax, a cover 40 that covers the second housing 11, and an inter-board connector. The first circuit board 60 is mounted with a plurality of switching elements 252, which are field-effect transistors that output a current to excite a motor coil, and a rotation angle sensor 23a positioned on the extension of the axial direction Ax of the shaft 31. The first circuit board is located on the non-load side of the shaft 31. The second circuit board 20 has a control circuit 24 that controls the current supplied to the plurality of switching elements 252. The inter-board connector connects the second circuit board 20, located on the non-load side of the second housing 11, and the first circuit board 60, located on the load side of the second housing 11, and is located in the first through-hole 119.

[0155] This ensures that the inter-board connector transmits control signals, while the second heatsink enhances heat dissipation for both the first and second circuit boards.

[0156] The second housing 11 houses the second circuit board 20 and is sandwiched between the first circuit board 60 and the second circuit board 20, acting as a heat sink that receives heat from the electronic components of the first circuit board 60 and the electronic components of the second circuit board 20. The support 70 is provided on the non-load side of the first circuit board 60 and acts as a heat sink that receives heat from the electronic components of the first circuit board 60. The heat sink 29 is provided on the load side of the second circuit board 20 and receives heat from the electronic components of the second circuit board 20. The cover 40 covers the non-load side of the second housing 11, and the cover 40 and the second housing 11 surround the second circuit board 20, the heat sink 29, and the power wiring module 90.

[0157] As a result, the heat sink support 70, the first circuit board 60, the second housing 11 (also a heat sink), the second circuit board 20, the heat sink 29, the power wiring module 90, and the cover 40 are arranged in order along the axial direction. Consequently, the volume inside the housing can be suppressed while improving the airtightness inside the housing and suppressing the temperature rise inside the housing.

[0158] The ECU 10 includes a first circuit board 60, a second circuit board 20, a second housing 11 housing the second circuit board 20, a metal cover 40 covering the second housing 11, a connector CNT2 having power input terminals PWCH1 and PWCH2 that penetrate the cover 40, a power wiring module 90, and a heat sink 29. The first circuit board 60 is mounted with a plurality of switching elements 252, which are field-effect transistors that output a current to excite a motor coil, and a rotation angle sensor 23a positioned on the extension of the axial direction Ax of the shaft 31. The first circuit board is located on the non-load side of the shaft 31. The second circuit board 20 has a control circuit 24 that controls the current supplied to the plurality of switching elements 252. The power wiring module 90 is molded in resin and includes a choke coil 91 and a capacitor 92 for noise suppression, a lead frame wiring with one end connected to the power input terminal PWin and supplying power to the first circuit board 60 and the second circuit board, a first power terminal connected to the first circuit board, and a second power terminal connected to the second circuit board. The heatsink 29 is sandwiched between the power wiring module 90 and the second circuit board 20, with the power wiring module 90 sandwiched between the heatsink 29 and the cover 40.

[0159] As a result, the power wiring in the power wiring module 90 reduces the area of ​​the power wiring on the first circuit board 60. Consequently, the area of ​​the first circuit board 60 is reduced, and the radial size of the ECU 10 becomes smaller. In addition, since the power wiring module 90 is sandwiched between the second housing 11 and the heat sink 29, the heat dissipation of the choke coil 91 can be improved. As a result, the temperature rise inside the second housing 11 is suppressed.

[0160] Connector CNT2 will be used as an example to explain the connector CNT. Connector CNT2 has a base portion 48, a socket portion 49 protruding from the base portion 48 toward the non-load side, a connector terminal 484 inserted into a through hole 42H of the cover 40, and two sealing members CNO2. The base portion 48 has a visor portion 481 whose outer edge protrudes toward the load side beyond the back surface 482 of the base portion 48, surrounding the outer edge of the connector base portion of the cover 40 and covering a part of the side surface 451 of the connector base portion, and a sealing support portion 483 which, together with the connector terminal 484, protrudes toward the load side beyond the back surface 482 of the base portion 48 and is inserted into the through hole 42H of the cover 40. The sealing member CNO2 is sandwiched between the first inner wall 452 of the through hole 42H and the sealing support portion 483.

[0161] As a result, even if high-pressure water attempts to enter from the outside, the eaves portion 481 suppresses the intrusion of water. Even if water penetrates beyond the eaves portion 481, the sealing member CNO2 sandwiched between the first inner wall 452 of the through hole 42H and the sealing support portion 483 suppresses the intrusion of water. As a result, the waterproof level of the electric drive unit 1 is improved, and sufficient waterproofing can be maintained even under high water pressure. Furthermore, the electric drive unit 1 can meet the IPx9K standard of JIS D 5020.

[0162] Since the lid 40 is made of metal, it has high heat dissipation properties, which suppresses the deterioration of the sealing material CNO2 and improves waterproofing at high temperatures.

[0163] Furthermore, the electric power steering system 100 is equipped with the electric drive unit 1 described above, and the electric drive unit 1 generates auxiliary steering torque. As described above, the electric drive unit 1 can improve waterproofing even under high water pressure. As a result, the reliability of the electric drive unit 1 is improved, and therefore the reliability of the electric power steering system 100 is also improved.

[0164] (Embodiment 2) Figure 20 is an exploded cross-sectional view of the lid and connector according to Embodiment 2. Figure 21 is a cross-sectional view of the assembled lid and connector according to Embodiment 2. The same reference numerals are used for the same components as those described in Embodiment 1 above, and redundant descriptions are omitted. The lid 40 of Embodiment 2 differs from that of Embodiment 1 in that it has a groove 457 in the second bottom portion 455.

[0165] As shown in Figures 20 and 21, the sealing member CNO2 is housed in a seal housing space surrounded by the back surface 482 of the base 48, the first inner wall 452, the first bottom 453, and the side surface 483S of the sealing support portion 483. Grease is sealed in the seal housing space along with the sealing member CNO2. It is undesirable for the grease to enter the interior of the second housing 11. Therefore, a part of the second bottom 455 is recessed to form the groove 457 so that the groove 457 can store the grease. When viewed in the axial direction Ax, the groove 457 has the shape of an annular ring that encircles the outer circumference of the third inner wall 456 of the through hole 42H. The groove 457 is not limited to an annular shape, and may have a shape in which a part of the annular ring is intermittently recessed.

[0166] In Embodiment 2, unlike Embodiment 1, two positioning protrusions 46 are located on the second surface 45 of the cover 40, and two recesses 46H are located on the back surface 482 of the base 48. When the positioning protrusions 46 are inserted into the recesses 46H, the temporary position of the connector CNT2 relative to the connector base is determined.

[0167] (Embodiment 3) Figure 22 is an explanatory diagram illustrating the position of the connector hole through which the fixing member passes in the connector according to Embodiment 3. Note that the same reference numerals are used for components that are the same as those described in Embodiment 1 above, and redundant explanations are omitted. The arrangement of the connector hole CNTH in Embodiment 3 differs from Embodiment 1 in that it has [specific features / features].

[0168] The base 48 of the connector CNT and the cover 40 are connected by multiple fixing members B5. As shown in Figure 22, connector holes CNTH are opened in the base 48 through which the fixing members B5 pass. The angle between the center CNTHC of adjacent connector holes CNTH and the center 483C of the sealing support portion 483 is 120°. The angles between the center CNTHC of adjacent connector holes CNTH and the center 483C of the sealing support portion 483 are equal. As a result, when the base 48 of the connector CNT is attached to the cover 40 and the sealing support portion 483 is inserted into the through hole 42H together with the connector terminals 484, the sealing support portion 483 presses the sealing member CNO2 against the first inner wall 452, and the sealing member CNO2 is naturally compressed. Then, when the fixing members B5 are fastened, a stress is applied that presses the base 48 of the connector CNT against the cover 40. Since the fixing member B5 is arranged at equiangled angles around the sealing member CNO2, it is less likely to cause unintended deformation of the sealing member CNO2. As a result, the lifespan of the sealing member CNO2 is extended, and the reliability of the electric drive unit 1 is improved.

[0169] (Embodiment 4) Figure 23 is a schematic diagram of an electric power steering device according to Embodiment 4. Note that the same reference numerals are used for components that were described in Embodiments 1 to 3 above, and redundant explanations are omitted.

[0170] As shown in Figure 23, the electric power steering device 100A of Embodiment 4 is a pinion assist type that provides auxiliary steering torque to the steering shaft 192. As shown in Figure 23, the steering shaft 192 comprises an input shaft 192A and an output shaft 192B. One end of the input shaft 192A is connected to the steering wheel 191, and the other end is connected to a torsion bar. One end of the output shaft 192B is connected to a torsion bar, and the other end is connected to a universal joint 196. The torque sensor 194 detects the steering torque applied to the steering shaft 192 by detecting the twist of the torsion bar. The torque sensor 194 outputs a steering torque signal T corresponding to the detected steering torque to the ECU 10 via CAN communication. The steering shaft 192 rotates due to the steering force applied to the steering wheel 191.

[0171] The intermediate shaft 197 transmits torque from the output shaft 192B. The first rack and pinion mechanism 199 includes a first pinion shaft 199A, a first pinion gear 199B, a rack shaft 199C, and a first rack 199D. One end of the first pinion shaft 199A is connected to the intermediate shaft 197 via a universal joint 198, and the other end is connected to the first pinion gear 199B. The first rack 199D formed on the rack shaft 199C meshes with the first pinion gear 199B.

[0172] The rotational motion of the steering shaft 192 is transmitted to the first rack and pinion mechanism 199 via the intermediate shaft 197. This rotational motion is converted into linear motion of the rack shaft 199C by the first rack and pinion mechanism 199. Tie rods 172 are connected to both ends of the rack shaft 199C, respectively.

[0173] (Embodiment 5) Figure 24 is a schematic diagram of an electric power steering device according to Embodiment 5. Note that the same reference numerals are used for components that are the same as those described in Embodiments 1 to 2 above, and redundant explanations are omitted. The electric power steering device 100B shown in Figure 24 is a pinion assist type that provides auxiliary steering torque to the first pinion shaft 199A. In the electric power steering device 100B, the torque sensor 194 is connected to the first pinion shaft 199A.

[0174] The motor 30 rotates the reduction gear 175 of the worm shaft. The worm wheel of the reduction gear 175 rotates together with the first pinion shaft 199A. As a result, the motor 30 can rotate the first pinion gear 199B. The first pinion gear 199B meshes with the first rack 199D. As a result, the electric drive unit 1 applies assist force to the first rack 199D via the reduction gear 175. The first pinion gear 199B may be orthogonal to the first rack 199D, or it may be obliquely positioned. As described above, the electric power steering device 100B of Embodiment 3 is a single-pinion assist system.

[0175] (Embodiment 6) Figure 25 is a schematic diagram of an electric power steering device according to Embodiment 6. Note that the same reference numerals are used for components that are the same as those described in Embodiments 1 to 3 above, and redundant explanations are omitted. The electric power steering device 100C includes a first pinion shaft 199A and a first pinion gear 199B, as well as an output shaft 192B and a second pinion gear 171B. The electric power steering device 100C is a dual-pinion assist system. The torque sensor 194 detects the torque between the pinion shaft 195 and the first pinion gear 199B.

[0176] The motor 30 rotates the reduction gear 175 of the worm shaft. The worm wheel of the reduction gear 175 rotates together with the output shaft 192B. As a result, the motor 30 can rotate the second pinion gear 171B. The second pinion gear 171B meshes with the second rack 171C. As a result, the electric drive unit 1 applies assist force to the second rack 171C via the reduction gear 175. The second pinion gear 171B may be orthogonal to the second rack 171C, or it may be obliquely positioned. The electric power steering device 100C of Embodiment 4 is a dual pinion assist system. [Explanation of Symbols]

[0177] 1. Electric drive unit 10 ECU 11. Second Housing 11R Containment Space 20 2nd circuit board 23 Detection circuit 23a Rotation Angle Sensor 23b Motor rotation speed calculation unit 24 Control circuits 25A First Power Circuit 25B Second Power Circuit 29 Heatsink 30 motors 30G gear 31 shafts 31a Rotation Angle Sensor 32 magnets 40 Lid 41H, 42H, 43H through hole 44 Page 1 45 Side 2 48 Base 49 Socket section 60 1st circuit board 60A, Side 1 60B 2nd side 61 Receptacle 62 plugs 70 Support 71 First top plate 72 Base 78 Female thread section 79 Second top plate 80 Terminal Blocks 81 Base 90 Power Wiring Modules 93 1st power supply terminal 96 2nd power supply terminal 97 Base 100, 100A, 100B, 100C Electric Power Steering System 451 Side view 452 First Inner Wall 453 1st bottom 454 Second Inner Wall 455 2nd bottom 456 Third Inner Wall 457 Groove 481 Eaves 481P end 481S interior wall 482 Back side 483 Sealing support part 483C center 483P end 483S side 484 Connector terminals 489 Gap 490 Reference plane 491 recess 930 Housing No. 1 931 Motor Stator 932 Motor Rotor Ax axis direction G1, G2 gap

Claims

1. An electric drive device comprising a motor and an electronic control device for controlling the rotation of the motor, The aforementioned motor is A shaft extending axially from the load side to the non-load side, A motor rotor that is linked to the aforementioned shaft, A motor stator having a motor coil and motor coil wiring for supplying power to the motor coil, and which rotates the motor rotor, A first housing that houses the motor rotor and the motor stator inside, Includes, The aforementioned electronic control device is Circuit board and The second housing and A metal lid that houses at least a portion of the circuit board between itself and the second housing and covers the second housing, A connector attached to the cover, Includes, The aforementioned cover is Page 1 and, A connector base portion having a second surface on the non-load side from which a part of the cover protrudes to the non-load side from the first surface, and a side surface between the first surface and the second surface, The connector base portion has a through hole that penetrates from the second surface on the non-load side to the back surface on the load side, It has, The aforementioned connector is base and A socket portion that protrudes from the base toward the non-load side and receives the plug, A connector terminal to be inserted into the aforementioned through hole, Sealing member and It has, The aforementioned base is, The outer edge protrudes on the load side beyond the back surface of the base, surrounds the outer edge of the connector base, and covers a part of the side surface of the connector base, and It has a sealing support portion that protrudes from the back surface of the base toward the load side and is inserted into the through hole, and is arranged around the connector terminal, together with the connector terminal, The back surface of the base and the second surface of the lid are in close contact. The through hole has a first inner wall having a first diameter, a second inner wall having a second diameter smaller than the first diameter, and a first bottom between the first inner wall and the second inner wall. The sealing member is housed in a seal housing space surrounded by the back surface of the base, the first inner wall, the first bottom, and the sealing support portion, and is sandwiched between the first inner wall of the through hole and the sealing support portion. Electric drive system.

2. The electric drive device according to claim 1, wherein there is a gap between the back surface of the base and the sealing member, and between the first bottom and the sealing member, at least one of these gaps.

3. The through hole has a third inner wall having a third diameter smaller than the second diameter, and a second bottom between the second inner wall and the third inner wall. The electric drive device according to claim 1, wherein the sealing support portion abuts against the second inner wall and does not abut against the second bottom.

4. The through hole has a third inner wall having a third diameter smaller than the second diameter, and a second bottom between the second inner wall and the third inner wall. The seal housing space is filled with grease along with the sealing member. The electric drive device according to claim 1, further comprising a groove provided in the second bottom portion that is recessed toward the load side.

5. The electric drive device according to claim 1, wherein the sealing support portion is cylindrical in shape.

6. The base of the connector and the cover are connected by a plurality of fixing members. Multiple connector holes are provided in the base through which each of the aforementioned fixing members passes. The electric drive device according to claim 1, wherein the angle between the centers of adjacent connector holes and the center of the sealing support portion is equal.

7. The distance between the eaves portion and the first surface of the cover is narrower than the distance between the eaves portion and the side surface of the connector base portion. The electric drive device according to claim 1.

8. The aforementioned circuit board is A transistor that outputs a current to excite the motor coil and a rotation angle sensor positioned on the axial extension of the shaft are mounted on the first circuit board positioned on the load side of the second housing, The second housing has a second circuit board positioned on the non-load side and having a control circuit for controlling the power circuit having the transistor, The cover houses the second circuit board between itself and the second housing. The first housing accommodates the first circuit board. The electric drive device according to claim 1.

9. The electric drive device is provided according to any one of claims 1 to 8, An electric power steering system in which the aforementioned electric drive device generates auxiliary steering torque.

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