Electric drive device and electric power steering device

Abstract

The present application provides an electric drive device and an electric power steering device that can be reduced in axial size and can suppress stress applied to a circuit board accompanying electrical connection with a motor and the circuit board even when a junction box is mounted. The electric drive device includes a motor and an electronic control device that controls rotation of the motor. The electronic control device includes a first circuit board, a first heat sink, a second heat sink that sandwiches the first circuit board between the first heat sink and the second heat sink, and a junction box that is fixed to a side surface of the second heat sink and electrically connects a motor coil wiring and the first circuit board.

Description

Technical Field

[0001] This invention relates to an electric drive device and an electric power steering device having an electronic control device for controlling the rotation of a motor. Background Technology

[0002] Electric power steering systems that use a motor to generate auxiliary steering torque include an electronic control unit that controls the motor. For example, Patent Document 1 describes a drive unit that integrates the motor and the control unit that controls the motor.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-239296 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] In the electric drive device of Patent Document 1, there is a junction box (terminal block) that connects the motor wiring of the motor and the terminals of the power module. As a result, the motor and the control unit can be easily connected or disconnected without special tools.

[0008] In contrast, there is a requirement to mount field-effect transistors (FETs) on the circuit board to reduce the height of the power module and make it miniaturized.

[0009] However, since the junction box and motor wiring are electrically connected by pressing with threaded parts, stress associated with the pressing is sometimes applied to the circuit board. The circuit board is also subjected to thermal stress due to the heat generated by the field-effect transistors, so it is desirable to suppress the stress from the junction box.

[0010] The present invention was made in view of the above-mentioned problems, and its object is to provide an electric drive device and an electric power steering device that can be miniaturized in the axial direction and can suppress the stress on the circuit board that accompanies the electrical connection between the motor and the circuit board even when a junction box is installed.

[0011] Solution for solving the problem

[0012] To achieve the above objectives, one technical solution provides an electric drive device comprising a motor and an electronic control device for controlling the rotation of the motor. The motor includes: a shaft extending axially from a load side toward the opposite side of the load; a motor rotor coupled to the shaft; a motor stator having motor coils and motor coil wiring for supplying power to the motor coils, the motor stator causing the motor rotor to rotate; a first housing housing the motor rotor and the motor stator inside; and a magnet disposed on the opposite side of the load on the shaft. The electronic control device includes: a first circuit board, which is equipped with... The first circuit board, located on the load-opposite side of the shaft, is equipped with a transistor and a rotation angle sensor. The transistor outputs a current that excites the motor coil, and the rotation angle sensor is disposed on the axial extension of the shaft. A first heat sink is located on the load-opposite side of the first circuit board. A second heat sink is located on the load side of the first circuit board, with the first circuit board sandwiched between the second heat sink and the first heat sink. A junction box is fixed to the side of the second heat sink, electrically connecting the motor coil wiring to the first circuit board.

[0013] Thus, the first circuit board is axially clamped by the first and second heat sinks. Therefore, the axial displacement parallel to the motor shaft can be suppressed, and the electric drive unit becomes smaller. The junction box is fixed and supported on the side of the second heat sink. Therefore, even if the junction box is pressed by the threaded parts, the stress associated with the pressing will act on the second heat sink, thereby reducing the stress acting on the first circuit board. As a result, the lifespan of the first circuit board is extended, and the reliability of the electric drive unit is improved.

[0014] As an ideal technical solution, the first housing has a tool insertion hole, and the motor has a side cover that blocks the tool insertion hole and can be detached from the first housing. Thus, by removing or attaching the side cover, the motor can be easily connected to or disconnected from the electronic control device.

[0015] As an ideal technical solution, the transistor is mounted on the first heat sink side of the first circuit board, and an electrolytic capacitor is mounted on the second heat sink side. Thus, both sides of the first circuit board are effectively utilized, and the first circuit board can also be miniaturized radially.

[0016] As an ideal technical solution, the second heat sink has a top plate covering the electrolytic capacitor, and the magnet is inserted into an axial through-hole in the top plate at a position that does not overlap with the electrolytic capacitor. This allows for improved cooling of the electrolytic capacitor through heat conduction to the top plate of the second heat sink. Furthermore, the side of the second heat sink, sized according to the axial dimensions of the electrolytic capacitor, can be used as a contact surface for abutting the junction box. Additionally, since the magnet is inserted at a position that does not overlap with the electrolytic capacitor, the space radially outer side of the magnet can be used as a placement area for the electrolytic capacitor. Consequently, the axial dimensions of the electric drive device are reduced.

[0017] As an ideal technical solution, the top plate has steps corresponding to the height of the plurality of electrolytic capacitors. Thus, the second heat sink has a minimum volume corresponding to the size of each electrolytic capacitor, contributing to the weight reduction of the electric drive device.

[0018] As an ideal technical solution, the electric drive device has a second circuit board with a control circuit for controlling a power circuit having the transistor. The second circuit board is disposed on the opposite side of the load of the first heat sink and is electrically connected to the first circuit board via a substrate connector inserted into an axial through-hole in the first heat sink. Thus, both axial surfaces of the first heat sink can be used as heat dissipation surfaces.

[0019] As an ideal technical solution, the electric drive device also includes a second circuit board having a control circuit for controlling the current supplied to the transistor, the second circuit board being housed in a receiving space provided in the first heat sink. Thus, the axial size of the electric drive device is reduced.

[0020] As an ideal technical solution, the motor stator includes a first motor coil wiring connected to a first coil group and a second motor coil wiring connected to a second coil group. A junction box electrically connecting the first motor coil wiring to the first circuit board and another junction box electrically connecting the second motor coil wiring to the first circuit board are positioned to sandwich the second heat sink. Thus, even with redundant coil wiring, the radial size of the motor can be suppressed by utilizing multiple sides of the second heat sink.

[0021] As an ideal technical solution, the first heat sink and the second heat sink are connected by a fixing member. Therefore, even if the junction box is pressed by the threaded part, the stress associated with the pressing will act on the second heat sink and be transmitted to the first heat sink via the bolt. As a result, the stress applied to the first circuit board is further reduced.

[0022] As an ideal technical solution, the electric drive device further comprises: a metal cover covering the first heat sink; a connector having a power input terminal penetrating the cover; a power wiring module molded from resin for a noise-reduction choke coil, a capacitor, a lead frame wiring connected at one end to the power input terminal to supply power to the first and second circuit boards, a first power terminal connected to the first circuit board, and a second power terminal connected to the second circuit board; and a third heat sink sandwiching the power wiring module between itself and the cover. Thus, the presence of power wiring within the power wiring module reduces the area of ​​the power wiring on the first circuit board. Consequently, the area of ​​the first circuit board is reduced, and the radial size of the electronic control device is decreased. Furthermore, since the power wiring module is sandwiched between the third heat sink and the cover, the heat dissipation of the choke coil is improved. Consequently, temperature rise within the first heat sink is suppressed.

[0023] As an ideal technical solution, multiple first positioning protrusions of the power wiring module protrude towards the cover, and the first positioning protrusions are inserted into the positioning holes of the cover. This facilitates the assembly of the power wiring module onto the cover, and prevents the power wiring module from accidentally contacting the connector.

[0024] As an ideal technical solution, the third heat sink has a first recess, the cover has a second recess, the first surface of the choke coil protrudes from the first surface of the power wiring module and is inserted into the first recess, and the second surface of the choke coil protrudes from the second surface of the power wiring module on the side opposite to the first surface of the power wiring module and is inserted into the second recess. Thus, the heat dissipation of both sides of the choke coil is improved.

[0025] As an ideal technical solution, the first power terminal is longer than the second power terminal. Thus, power is supplied from the power wiring module to both the first and second circuit boards, which are located at different positions in the axial direction.

[0026] As an ideal technical solution, in the power wiring module, the resin at the base of both the first power terminal and the second power terminal is thicker than the surrounding portion of the base. Therefore, the first power terminal and the second power terminal are less likely to tilt relative to the axial direction.

[0027] As an ideal technical solution, the motor coil includes a first coil system and a second coil system. The first circuit board includes a first power circuit supplying current to the first coil system and a second power circuit supplying current to the second coil system. The lead frame wiring of the power wiring module includes the first power circuit and the second power circuit. A first power terminal of the first power circuit is connected to the first power circuit, and a first power terminal of the second power circuit is connected to the second power circuit. Thus, the power wiring module independently receives power from both systems. As a result, even if one power system is not functioning, the other power system can still function, increasing the continuous functionality of the electric drive device.

[0028] As an ideal technical solution, a through hole for inputting power is formed in the resin in the space adjacent to the power input section of the lead frame wiring. The power input terminal of the connector, which penetrates the cover, is inserted into the through hole for inputting power, thereby electrically connecting the power input section and the power input terminal. This allows for the electrical connection of the connector and the power wiring module while ensuring insulation and suppressing axial thickness.

[0029] As an ideal technical solution, the third heat sink has a first base surface and a second base surface opposite to the first base surface. The second circuit board has an integrated circuit, which faces the first base surface. The noise-removing choke coil and the capacitor of the power wiring module face the second base surface. Thus, the heat generated by the integrated circuit is transferred to the heat sink, suppressing the temperature rise of the integrated circuit. Furthermore, the heat generated by the noise-removing choke coil and the capacitor is transferred to the heat sink.

[0030] As an ideal technical solution, the third heat sink has a heat dissipation surface protruding from the first base surface towards the second circuit board, and the heat dissipation surface is located at a position overlapping the integrated circuit in the axial direction. Thus, the heat generated by the integrated circuit constituting the control circuit is efficiently transferred to the heat sink.

[0031] As an ideal technical solution, an electric power steering device is provided, wherein the electric power steering device includes the aforementioned electric drive device, which generates auxiliary steering torque. This allows for the suppression of axial deviations parallel to the motor shaft, increasing the flexibility in the configuration of the electric power steering device. Furthermore, the improved reliability of the electric drive device also enhances the overall reliability of the electric power steering system.

[0032] The effects of the invention

[0033] According to the present invention, an electric drive device and an electric power steering device are provided that can be miniaturized in the axial direction and can suppress the stress on the first circuit board that accompanies the electrical connection between the motor and the first circuit board even when a junction box is installed. Attached Figure Description

[0034] Figure 1 This is a perspective view schematically showing a vehicle equipped with an electric power steering system according to the embodiment.

[0035] Figure 2 This is a schematic diagram of the electric power steering device according to the embodiment.

[0036] Figure 3 This is a side view showing an example of the configuration of the ECU in the implementation method.

[0037] Figure 4 It is a cross-sectional view of a motor schematically representing an embodiment.

[0038] Figure 5 This is a schematic diagram showing the wiring of the motor in an embodiment.

[0039] Figure 6 This is an explanatory diagram showing the relationship between the motor and the ECU in the implementation method.

[0040] Figure 7 This is an exploded perspective view showing a structural example of an electric drive device according to an embodiment.

[0041] Figure 8 This is a perspective view showing an example of the structure of an ECU in an embodiment.

[0042] Figure 9 This is an exploded perspective view showing an example of the structure of the ECU in the embodiment.

[0043] Figure 10A This is an exploded perspective view showing a structural example of mounting the junction box of the embodiment onto the power board.

[0044] Figure 10B This is an exploded perspective view showing a structural example of mounting motor coil wiring to the junction box in the embodiment.

[0045] Figure 11 This is a perspective view showing a structural example of mounting the junction box of the embodiment onto the power board.

[0046] Figure 12 This is an exploded perspective view showing a structural example of mounting the control board of the embodiment onto the wiring module.

[0047] Figure 13A This is a top-view perspective view of the heat sink in the implementation method.

[0048] Figure 13B This is an explanatory diagram illustrating the positional relationship between the heat dissipation surface of the heat sink and the second circuit board in the embodiment.

[0049] Figure 13C This is a top perspective view of the second circuit board of the embodiment.

[0050] Figure 14 This is a top view showing the upper surface of the cover and connector of the second circuit board of the embodiment on which it is mounted.

[0051] Figure 15 It means Figure 14 A sectional view of the XV-XV section.

[0052] Figure 16 It means Figure 14 A sectional view of section XVI-XVI.

[0053] Figure 17 This is an exploded perspective view showing an example of the structure of the cover and connector in the embodiment.

[0054] Figure 18 This is an explanatory diagram showing the fixture for assembling the cover body into the second housing of the embodiment.

[0055] Figure 19A This is a top view showing the power wiring module of the embodiment opposite to the load.

[0056] Figure 19B This is a top view showing the load side of the power wiring module in the embodiment.

[0057] Figure 19C This is a perspective view of the power wiring module in the implementation method.

[0058] Figure 20 This is a circuit diagram showing the equivalent circuit of the power wiring module in the implementation method.

[0059] Figure 21 It means Figure 14 A sectional view of a partial section of XXI-XXI.

[0060] Figure 22 It means Figure 14 A sectional view of a partial section of XXII-XXII.

[0061] Figure 23 It means Figure 14 A sectional view of a partial section of section XXIII-XXIII. Detailed Implementation

[0062] Referring to the accompanying drawings, the embodiments for carrying out the present invention are described in detail. The present invention is not limited to the content described in the following embodiments. Furthermore, the structural elements described below include content readily conceived by those skilled in the art and substantially the same content. Moreover, the structural elements described below can be appropriately combined.

[0063] Figure 1 This is a perspective view schematically showing a vehicle equipped with an electric power steering system according to the embodiment. Figure 2 This is a schematic diagram of the electric power steering system according to an embodiment. Figure 1 As shown, vehicle 101 is equipped with an electric power steering system 100. (Refer to...) Figure 2 To illustrate the general outline of the electric power steering system 100.

[0064] The electric power steering system 100 includes 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, in the sequence of force transmission applied by the driver (operator). Additionally, the electric power steering system 100 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 an ECU (Electronic Control Unit)) 10 for controlling the motor 30, a reduction gear 175, and a second rack and pinion mechanism 170. A vehicle speed sensor 182, a power supply unit 183 (e.g., an onboard battery), and an ignition switch 184 are located on the vehicle body. The vehicle speed sensor 182 detects the vehicle speed 101. The vehicle speed sensor 182 outputs the detected vehicle speed signal SV to the ECU 10 via CAN (Controller Area Network) communication. When the ignition switch 184 is on, power is supplied to the ECU 10 from the power supply unit 183.

[0065] The electric drive unit 1 includes a motor 30 and an ECU 10 fixed on the opposite side of the load on the shaft 31 of the motor 30. Alternatively, the electric drive unit 1 may also include an adapter that connects the ECU 10 and the motor 30.

[0066] like Figure 2As shown, the steering shaft 192 includes 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. Furthermore, a torque sensor 194 detects the steering torque applied to the steering shaft 192 by detecting the torsion of the torsion bar 192C. The torque sensor 194 outputs a steering torque signal T corresponding to the detected steering torque to the ECU 10. The steering shaft 192 rotates under the influence of the steering force applied to the steering wheel 191.

[0067] The intermediate shaft 197 has an upper shaft 197A and a lower shaft 197B for transmitting torque from the output shaft 192B. The upper shaft 197A is connected to the output shaft 192B via a universal joint 196. On the other hand, the lower shaft 197B is connected to the first pinion shaft 199A of the first gear and rack mechanism 199 via a universal joint 198. The upper shaft 197A and the lower shaft 197B are, for example, connected by a spline joint.

[0068] The first gear and rack mechanism 199 includes a first pinion shaft 199A, a first pinion 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 199B. The first rack 199D, formed on the rack shaft 199C, meshes with the first pinion 199B. The rotational motion of the steering shaft 192 is transmitted to the first gear and rack mechanism 199 via the intermediate shaft 197. This rotational motion is converted into linear motion of the rack shaft 199C by the first gear and rack mechanism 199. A pull rod 172 is connected to both ends of the rack shaft 199C.

[0069] Motor 30 is a motor that generates auxiliary steering torque to assist the driver's control. Motor 30 can be either a brushless motor or a brushed motor with brushes and a commutator.

[0070] ECU 10 includes a rotation angle sensor 23a. Rotation angle sensor 23a is used to detect the rotation phase of motor 30. ECU 10 obtains the rotation phase signal of motor 30 from rotation angle sensor 23a, the steering torque signal T from torque sensor 194, and the vehicle speed signal SV of vehicle 101 from vehicle speed sensor 182. ECU 10 calculates the auxiliary steering command value based on the rotation phase signal, steering torque signal T, and vehicle speed signal SV. ECU 10 supplies current to motor 30 according to the calculated auxiliary steering command value.

[0071] The reduction gear 175 includes a worm 175A that rotates integrally with the shaft 31 of the motor 30 and a worm wheel 175B that meshes with the worm 175A. Therefore, the rotational motion of the shaft 31 is transmitted to the worm wheel 175B via the worm 175A. Furthermore, in this embodiment, the portion of the shaft 31 closest to the reduction gear 175 is referred to as the load-side end, and the portion of the shaft 31 opposite to the reduction gear 175 is referred to as the load-opposite end.

[0072] The second gear and rack mechanism 170 has a second pinion shaft 171A, a second pinion 171B, and a second rack 171C. The second pinion shaft 171A is fixed so that one end is coaxial with and integrally rotates with the worm gear 175B. The other end of the second pinion shaft 171A is connected to the second pinion 171B. The second rack 171C, formed on the rack shaft 199C, meshes with the second pinion 171B. The rotational motion of the motor 30 is transmitted to the second gear and rack mechanism 170 via the reduction gear 175. This rotational motion is converted into linear motion of the rack shaft 199C by the second gear and rack mechanism 170.

[0073] 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 as an axial force applied to the rack shaft 199C. At this time, the ECU 10 obtains the steering torque signal T input to the steering shaft 192 from the torque sensor 194. The ECU 10 obtains the vehicle speed signal SV from the vehicle speed sensor 182. The ECU 10 obtains 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 auxiliary steering torque generated by the motor 30 is transmitted to the second rack and pinion mechanism 170 via the reduction gear 175. The second rack and pinion mechanism 170 transmits the auxiliary steering torque as an axial force applied to the rack shaft 199C. In this way, the driver can be assisted by the electric power steering device 100 when turning the steering wheel 191.

[0074] like Figure 2 As shown, the electric power steering system 100 is a double pinion type in which the second rack and pinion mechanism 170 is given auxiliary force, but it is not limited to this. The electric power steering system 100 can also be a single pinion type in which only the first pinion 199B is given auxiliary force. The electric power steering system 100 can also be a rack and pinion type with a pulley device and a ball screw device. It is not limited to this, for example, the electric power steering system 100 can also be a column type in which the steering shaft 192 is given auxiliary force.

[0075] Figure 3This is a side view illustrating an example configuration of the ECU in an implementation scheme. (Example) Figure 3 As shown, the electric drive unit 1 includes an ECU 10 and a 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. Figure 3 The CNT connector shown enables the wire harness to... Figure 2 The rack shaft 199C shown is inserted and pulled parallel to the direction in which it extends. In this embodiment, axial direction Ax refers to the direction parallel to the shaft 31 of the motor 30 (see reference). Figure 4 The direction in which it extends is parallel to the direction in which it extends.

[0076] The motor 30 includes a first housing 930. The first housing 930 is cylindrical. The first housing 930 is also referred to as the motor housing. The first housing 930 has a tool insertion hole 36H and a side cover 36 that blocks 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 junction box 80, described later, is exposed from the tool insertion hole 36H.

[0077] In addition, a waterproof and breathable filter 10B is provided in the housing of ECU10, i.e., the radiator. The waterproof and breathable filter 10B is breathable and waterproof, preventing moisture from entering. For example, when the pressure difference between the inside and outside of ECU10 increases due to temperature changes, air moves through the waterproof and breathable filter 10B to reduce the pressure difference.

[0078] Figure 4 It is a cross-sectional view of a motor schematically representing an embodiment. Figure 5 This is a schematic diagram showing the wiring of the motor in this embodiment. In this embodiment, circumferential direction refers to the direction along a concentric circle centered on axis 31. Radial direction refers to the direction away from axis 31 in a plane orthogonal to axis Ax. Figure 4 As shown, the motor 30 includes 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 has 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 circumferentially. The motor rotor 932 includes a rotor yoke 932a and magnets 932b. The magnets 932b are disposed on the outer circumferential surface of the rotor yoke 932a. The number of magnets 932b is, for example, 8. The rotation of the motor rotor 932 is linked to the rotation of the shaft 31.

[0079] like Figure 4As shown, the first motor coil 37 is concentratedly wound around each of the multiple teeth 931b. The first motor coil 37 is concentratedly wound around the outer periphery of the teeth 931b through an insulator. All of the first motor coils 37 are included in the first coil system. The inverter circuit 251 included in the first power circuit 25A (see reference...) Figure 6 The first coil system of the embodiment is energized by supplying current to it. The first coil system, for example, includes 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, are arranged at equal intervals in the circumferential direction. That is, the first coil system has three first coil groups Gr1 arranged at equal intervals in the circumferential direction. Furthermore, the number of first coil groups Gr1 is not necessarily three; when n is a natural number, 3n groups can be arranged at equal intervals in the circumferential direction. Additionally, n is preferably an odd number. As explained above, in this embodiment, there are multiple coil groups, and each three phases are divided into at least two systems: a first coil group Gr1 and a second coil group Gr2, and the stator core is energized using three-phase alternating current.

[0080] like Figure 4 As shown, the second motor coil 38 is wound around each of the multiple teeth 931b. The second motor coil 38 is wound around the outer periphery of the teeth 931b through an insulator. The teeth 931b where the second motor coil 38 is wound are different from the teeth 931b where the first motor coil 37 is wound. All of the second motor coils 38 are included in the second coil system. The inverter circuit 251 included in the second power circuit 25B (see reference) Figure 6 The second coil system is energized by supplying current to it. The second coil system, for example, includes six second motor coils 38. These six second motor coils 38 are arranged in a manner where two second motor coils 38 are adjacent to each other circumferentially. Three second coil groups Gr2, each consisting of adjacent second motor coils 38, are arranged at equal intervals circumferentially. That is, the second coil system has three second coil groups Gr2 arranged at equal intervals circumferentially. Furthermore, the number of second coil groups Gr2 is not necessarily three; when n is a natural number, it is sufficient to have 3n groups arranged at equal intervals circumferentially. Additionally, n is preferably an odd number.

[0081] like Figure 5As shown, the six first motor coils 37 include two first-phase motor coils 37Ua and 37Ub energized by the first-phase current I1u, two first-phase motor coils 37Va and 37Vb energized by the first-phase current I1v, and two first-phase motor coils 37Wa and 37Wb energized by the first-phase current I1w. The first-phase motor coils 37Ub are connected in series with respect to the first-phase motor coils 37Ua. The first-phase motor coils 37Vb are connected in series with respect to the first-phase motor coils 37Va. The first-phase motor coils 37Wb are connected in series with respect to the first-phase motor coils 37Wa. The winding direction of all the first motor coils 37 relative to the teeth 931b is the same. In addition, the first U-phase motor coil 37Ub, the first V-phase motor coil 37Vb, and the first W-phase motor coil 37Wb are connected by a star connection (Y connection).

[0082] like Figure 5 As shown, the six second motor coils 38 include two second-phase motor coils 38Ua and 38Ub energized by the second-phase current I2u, two second-phase motor coils 38Va and 38Vb energized by the second-phase current I2v, and two second-phase motor coils 38Wa and 38Wb energized by the second-phase current I2w. The second-phase motor coils 38Ub are connected in series with respect to the second-phase motor coils 38Ua. The second-phase motor coils 38Vb are connected in series with respect to the second-phase motor coils 38Va. The second-phase motor coils 38Wb are connected in series with respect to the second-phase motor coils 38Wa. The winding direction of all the second motor coils 38 relative to the teeth 931b is the same, and the same as the winding direction of the first motor coil 37. In addition, the second phase U motor coil 38Ub, the second phase V motor coil 38Vb, and the second phase W motor coil 38Wb are connected by a star connection (Y connection).

[0083] like Figure 4 As shown, the three first coil groups Gr1 consist of the first UV coil group Gr1UV, the first VW coil group Gr1VW, and the first UW coil group Gr1UW. The first UV coil group Gr1UV includes the first U-phase motor coil 37Ub and the first V-phase motor coil 37Va that are circumferentially adjacent to each other. The first VW coil group Gr1VW includes the first V-phase motor coil 37Vb and the first W-phase motor coil 37Wa that are circumferentially adjacent to each other. The first UW coil group Gr1UW includes the first U-phase motor coil 37Ua and the first W-phase motor coil 37Wb that are circumferentially adjacent to each other.

[0084] like Figure 4As shown, the three second coil groups Gr2 consist of the second UV coil group Gr2UV, the second VW coil group Gr2VW, and the second UW coil group Gr2UW. The second UV coil group Gr2UV includes the second U-phase motor coil 38Ub and the second V-phase motor coil 38Va, which are circumferentially adjacent to each other. The second VW coil group Gr2VW includes the second V-phase motor coil 38Vb and the second W-phase motor coil 38Wa, which are circumferentially adjacent to each other. The second UW coil group Gr2UW includes the second U-phase motor coil 38Ua and the second W-phase motor coil 38Wb, which are circumferentially adjacent to each other.

[0085] The first motor coil 37, excited by the first phase current I1u, is radially opposite the second motor coil 38, excited by the second phase current I2u, in the motor stator 931. In the following description, the radial direction of the motor stator 931 is only referred to as radial. For example, as... Figure 4 As shown, in the radial direction, the first U-phase motor coil 37Ua is opposite to the second U-phase motor coil 38Ua, and the first U-phase motor coil 37Ub is opposite to the second U-phase motor coil 38Ub.

[0086] The first motor coil 37, excited by the first phase current I1v, is radially opposite the second motor coil 38, excited by the second phase current I2v. For example, as... Figure 4 As shown, in the radial direction, the first V phase motor coil 37Va is opposite to the second V phase motor coil 38Va, and the first V phase motor coil 37Vb is opposite to the second V phase motor coil 38Vb.

[0087] The first motor coil 37, excited by the first phase current I1w, is radially opposite the second motor coil 38, excited by the second phase current I2w. For example, as... Figure 4 As shown, in the radial direction, the first W-phase motor coil 37Wa is opposite to the second W-phase motor coil 38Wa, and the first W-phase motor coil 37Wb is opposite to the second W-phase motor coil 38Wb.

[0088] Figure 6 This is a schematic diagram illustrating the relationship between the motor and the ECU in an embodiment. For example... Figure 6As shown, the ECU10 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 speed calculation unit 23b. The control circuit 24 includes a control calculation unit 241, a gate drive circuit 242, and a blocking drive circuit 243. The first power circuit 25A includes an inverter circuit 251 and a current blocking circuit 255. The second power circuit 25B includes an inverter circuit 251 and a current blocking circuit 255. Furthermore, the inverter circuit 251 includes multiple switching elements 252 and a shunt resistor SR for detecting current values. The shunt resistor SR is connected to the operational amplifier OP of the current detection circuit 254. Additionally, in... Figure 6 In this diagram, circuit details that do not require explanation are omitted. Three shunt resistors SR are connected to three switching elements 252 respectively. Alternatively, only one shunt resistor SR can be used, connecting the three switching elements 252 to that single shunt resistor SR.

[0089] The control calculation unit 241 calculates the motor current command value. The motor speed calculation unit 23b calculates the motor electrical angle θm and outputs it to the control calculation unit 241. The motor current command value output from the control calculation unit 241 is input to the gate drive circuit 242. The gate drive circuit 242 controls the first power circuit 25A and the second power circuit 25B according to the motor current command value. The gate drive circuit 242 includes a capacitor 256, which will be described later, on the power supply line.

[0090] like Figure 6 As shown, the ECU10 includes a rotation angle sensor 23a. The rotation angle sensor 23a is, for example, a magnetic sensor. The detection value of the rotation angle sensor 23a is supplied to the motor speed calculation unit 23b. The motor speed calculation unit 23b calculates the motor electrical angle θm based on the detection value of the rotation angle sensor 23a and outputs it to the control calculation unit 241.

[0091] 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 speed calculation unit 23b are input to the control calculation unit 241. The control calculation unit 241 calculates the motor current command value based on the steering torque signal T, the vehicle speed signal SV, and the motor electrical angle θm, and outputs it to the gate drive circuit 242.

[0092] The gate drive circuit 242 calculates the 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, based on the duty cycle of the first pulse width modulation signal, switches the switching element 252 to generate a three-phase AC current consisting of 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.

[0093] The gate drive circuit 242 calculates the 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, based on the duty cycle of the second pulse width modulation signal, switches the switching element 252 to generate a three-phase AC current consisting of 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 excites the second U-phase motor coils 38Ua and 38Ub, the second V-phase current I2v excites the second V-phase motor coils 38Va and 38Vb, and the second W-phase current I2w excites the second W-phase motor coils 38Wa and 38Wb.

[0094] Inverter circuit 251 is a power conversion circuit that converts direct current (DC) power to alternating current (AC) power. As described above, inverter circuit 251 has multiple switching elements 252. The switching elements 252 are, for example, field-effect transistors (FETs). Capacitors 253 are connected in parallel to inverter circuit 251. The first circuit board 60 has multiple capacitors 253 connected in parallel.

[0095] Additionally, 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. Furthermore, the current detection circuit 254 can also be configured to detect the current value of each phase of the motor 30.

[0096] A current blocking circuit 255 is configured between the inverter circuit 251 and the first motor coil 37, or between the inverter circuit 251 and the second motor coil 38. If the current value detected by the current detection circuit 254 is deemed abnormal, the control calculation unit 241 drives the current blocking circuit 255 using the blocking drive circuit 243 to block the current flowing from the inverter circuit 251 to the first motor coil 37. Furthermore, the control calculation unit 241 drives the current blocking circuit 255 using the blocking drive circuit 243 to block the current flowing from the inverter circuit 251 to the second motor coil 38. Thus, the current flowing to the first motor coil 37 and the current flowing to the second motor coil 38 are independently controlled by the control calculation unit 241. Additionally, input / 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.

[0097] Figure 7 This is an exploded perspective view showing a structural example of an electric drive device according to an embodiment. Figure 8 This is a perspective view showing an example of the structure of an ECU in an embodiment. For example... Figure 7 As shown, the electric drive unit 1 includes a motor 30 and an ECU 10 disposed on the load-opposite side of the motor 30.

[0098] At the end of shaft 31 opposite to the load, a magnet 32 ​​is mounted by means of a magnet bracket 32A. Half of the magnet 32 ​​is magnetized as the S pole and the other half as the N pole. Alternatively, the magnet 32 ​​may have S and N poles arranged alternately in the circumferential direction on its outer peripheral surface.

[0099] like Figure 7 As shown, the ECU 10 includes a first circuit board 60, a second circuit board 20, a second housing 11, a cover 40, a power wiring module 90, and a connector CNT. The second housing 11 is made of a metal with high heat dissipation properties, such as aluminum or copper. The second housing 11 functions as a heat sink to dissipate heat generated by the first circuit board 60 and the second circuit board 20. The cover 40 is also made of a metal with high heat dissipation properties, such as aluminum or copper, and is joined to the second housing 11. Thus, even if heat generated by the first circuit board 60 and the second circuit board 20 is transferred from the second housing 11, it can be efficiently dissipated to the outside through the cover 40.

[0100] The second housing 11 has a bottom 115 and sidewalls 116 surrounding the bottom 115. A receiving space 11R is provided inside the sidewalls 116. The receiving space 11R of the second housing 11 is sealed by covering it with a cover 40 via a sealing member OR2. The sealing member OR2 is a so-called O-ring formed of rubber or an elastomer. On the load-bearing opposite side of the bottom 115, there is a recess 117 for receiving electronic components.

[0101] 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 opposite side of the load side. When the cover 40 is installed in the second housing 11, the second circuit board 20 and the power wiring module 90 are accommodated in the accommodating space 11R of the second housing 11. As a result, the size of the ECU 10 in the axial direction Ax becomes smaller.

[0102] A flange 39 is provided at the end of the first housing 930 of the motor 30 on the opposite side of the load. An internal thread 39H is provided on the flange 39 along the axial direction Ax. A flange 111 is provided at the end of the second housing 11 on the load side. A through hole 111H is provided on the flange 111 along the axial direction Ax. A threaded fastening member B1 passes through the through hole 111H and is fastened to the internal thread 39H, thereby fixing the first housing 930 and the second housing 11.

[0103] Multiple flanges 131, 132, 141, 142, and 143 are provided at the end opposite to the load of the second housing 11. Flange 131 has a through hole 131H along the axial direction Ax. Flange 132 has a through hole 132H along the axial direction Ax. Flange 141 has an internal thread portion 141H along the axial direction Ax. Flange 142 has an internal thread portion 142H along the axial direction Ax. Flange 143 has an internal thread portion 143H along the axial direction Ax.

[0104] like Figure 8 As shown, the first circuit board 60 is sandwiched between the second housing 11 and the support 70. The support 70 is made of metals with high heat dissipation properties such as aluminum and copper, and is a heat sink with excellent heat dissipation. Two junction boxes 80 are installed on the side of the support 70.

[0105] Figure 9 This is an exploded perspective view showing an example of the structure of the ECU in the embodiment. Figure 10A This is an exploded perspective view showing a structural example of mounting the junction box of the embodiment onto the power board. For example... Figure 9 and Figure 10A As shown, the junction box 80 has a base 81, mounting accessories 82, and conductive terminals 83. The base 81 is formed 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.

[0106] Figure 10B This is an exploded perspective view showing an example of the structure for mounting motor coil wiring to the junction box in the embodiment. The other end of the conductive terminal 83 is electrically connected to the mounting fitting 82. (As shown...) Figure 10A and Figure 10B As shown, the installation accessory 82 is equipped with a supply Figure 7 and Figure 10BThe threaded fastener BM shown has a through hole 82H through which it 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. At the position where the through hole 82H and the through hole 32H communicate, the fastener BM passes through the through hole 82H and the through hole 32H and is fastened with a nut (not shown) on the back side of the first motor coil wiring 321 or the second motor coil wiring 322. Thus, one junction box 80 electrically connects the first circuit board 60 and the first motor coil wiring 321 of the motor 30, and another junction box 80 electrically connects the first circuit board 60 and the second motor coil wiring 322 of the motor 30. Furthermore, the mounting accessory 82 can be tightly fixed to the conductive terminal 83, or the mounting accessory 82 can be integrated with the conductive terminal 83 to become a single component.

[0107] The support 70 has a first top plate 71 and a second top plate 79 with different heights. The sizes of the first top plate 71 and the second top plate 79 vary according to the height of the capacitors 253 and 256 located between them and the first circuit board 60. Because heat dissipation material is placed between the capacitors 253 and 256 and the first top plate 71 and the second top plate 79, heat from the capacitors 253 and 256 is transferred to the first top plate 71 and the second top plate 79, thus suppressing the degradation of the capacitors 253 and 256. The capacitors 253 and 256 are, for example, electrolytic capacitors.

[0108] like Figure 9 As shown, the second housing 11 has a flat heat dissipation surface 112, a recess 113, and a protrusion 114 on the load side. A first through-hole 119 and a second through-hole 118 penetrate the second housing 11 along the axial direction Ax. A portion of the power wiring module 90 is inserted into the second through-hole 118, and a first power terminal 93 reaches the first circuit board 60. The plug 62 of the inter-board connector is inserted into the first through-hole 119, reaching the socket 61 of the second circuit board 20 (see reference). Figure 12 The inter-board connector transmits signals between the first circuit board 60 and the second circuit board 20. Furthermore, the inter-board connector having a plug 62 and a socket 61 is called a floating connector and has a movable portion capable of absorbing positional shifts during the engagement of the plug 62 and socket 61.

[0109] The protrusion 114 has an internal thread 114H that extends axially along Ax from the upper surface on the load side. A portion of the protrusions 114 are opposite to the support 70 in a notch 60N of the first circuit board 60. Other portions of the protrusions 114 are... Figure 10AThe through-hole 60H2 of the first circuit board 60 shown is opposite. The support body 70 has a through-hole 72H that extends through the support body 70 along the axial direction Ax. The fastening member B2, such as a threaded member, 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 internal thread portion 114H.

[0110] like Figure 10A As shown, the support body 70 has a base 72 and a first top plate 71 protruding from the base 72 toward the load side. Additionally, the support body 70 has two first side surfaces 74 and two second side surfaces 75. The first side surfaces 74 and the second side surfaces 75 respectively connect the base 72 and the first top plate 71. The support body 70 has two second top plates 79 extending in a second direction away from the two second side surfaces 75.

[0111] A through hole 76 extending axially through the first top plate 71 of the support 70 is provided. The magnet 32 ​​(see reference) is located at the end opposite the load side of the shaft 31. Figure 7 A through-hole 76 is inserted. As a result, the magnet 32 ​​is positioned near the rotation angle sensor 23a, which is mounted on the first circuit board 60. Additionally, a through-hole 77 is also provided on the side of the support 70. When the junction box 80 is mounted on the support 70, the through-hole 77 is blocked. Corresponding to the size of the through-hole 77, the support 70 achieves a lightweight design.

[0112] Figure 11 This is a perspective view showing a structural example of mounting the junction box of the embodiment onto a power board. Figure 11 The support body 70 shown has four internally threaded portions 78 that open to the opposite side of the load. When a threaded member or other fixing member B3 passes through the through hole 60H1 of the first circuit board 60 and is fastened to the internally threaded portions 78, as... Figure 11 As shown, the support body 70 and the first circuit board 60 are fixed in a close-fitting state. Ideally, the internal thread portions 78, which open diagonally to the opposite side of the load, are point-symmetrical. This facilitates the assembly of the support body 70 and the first circuit board 60.

[0113] like Figure 10A and Figure 11 As shown, the first circuit board 60 has multiple electronic components mounted on both sides of the substrate body. The substrate body of the first circuit board 60 is, for example, a printed circuit board formed of resin or the like. The multiple electronic components mounted on a single substrate body include field-effect transistors (FETs), magnetic sensors, electrolytic capacitors, resistive elements, diodes, thermistors, and application-specific integrated circuits (ASICs). The circuit board is composed of these multiple electronic components. Figure 6 The detection circuit 23, the first power circuit 25A, and the second power circuit 25B are shown.

[0114] like Figure 10A As shown, capacitors 253 and 256 are mounted on the first surface 60A of the first circuit board 60. Figure 9 As shown, when the support body 70 is mounted on the first circuit board 60, capacitors 253 and 256 are covered by the support body 70.

[0115] like Figure 10A As shown, 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 a component formed by sandwiching a non-magnetic layer between a pinned layer of a strongly magnetic material with its magnetization direction fixed (such as an antiferromagnetic layer) and a free layer of the strongly magnetic material. It is a sensor capable of detecting changes in the direction of magnetic flux. Spin valve sensors may include GMR (Giant Magneto Resistance) sensors or TMR (Tunnel Magneto Resistance) sensors. Furthermore, the rotation angle sensor 23a can be any sensor capable of detecting the rotation of the magnet 32. The rotation angle sensor 23a may also be, for example, an AMR (Anisotropic Magneto Resistance) sensor or a Hall effect sensor.

[0116] like Figure 10A As shown, a field-effect transistor TR and a shunt resistor SR, which are heat-generating electronic components, are disposed on the second surface 60B of the first circuit board 60. The field-effect transistor TR is not only disposed on... Figure 6 The switching element 252 shown is also provided on the wiring of the current blocking circuit 255, the blocking drive circuit 243, and the power supply voltage Vdc. Figure 6 As shown, the shunt resistor SR is connected to the current detection circuit 254.

[0117] The field-effect transistor (TR) is connected to a heat dissipation material called TIM (Thermal Interface Material) via a heat dissipation material. Figure 9 The heat dissipation surface 112 of the second housing 11 shown is in contact. The heat dissipation material is, for example, a material formed by mixing a thermally conductive filler with a silicon polymer. If the thermal conductivity is greater than that of the substrate body of the first circuit board 60, it can be a material other than those mentioned above. The shunt resistor SR is disposed in... Figure 9 The second housing 11 shown has a recess 113. Heat dissipation material is present in the recess 113.

[0118] like Figure 10AAs shown, legs 84 extend toward the support body 70 on both sides of the base 81 of the junction box 80, and through holes 85H are provided at the ends 85 of the legs 84. Threaded fasteners B4 pass through the through holes 85H and are fastened to the internal thread 73H of the contact surface 73 located on the first side surface 74.

[0119] Here, Figure 10A The abutment surface 73 of the first side surface 74 shown is with Figure 10B The contact surfaces of the fixing members BM of the mounting fitting 82 shown are parallel. Therefore, even if the junction box 80 is pressed by the fixing members BM such as threaded parts, the stress associated with the pressing is borne by the contact surface 73 of the first side surface 74 via the end 85 of the leg 84. As a result, deformation of the conductive terminal 83 and stress applied to the first circuit board 60 are suppressed.

[0120] As described above, the ECU 10 includes a first circuit board 60, a second housing 11, a support 70 serving as a heat sink, and a junction box 80. A field-effect transistor TR and a rotation angle sensor 31a are mounted on the first circuit board 60. The field-effect transistor TR outputs current to excite either the first motor coil 37 or the second motor coil 38. The rotation angle sensor 31a is positioned along the extension of the axial direction Ax of the shaft 31. The second housing 11 is located on the load-opposite side of the first circuit board 60. The support 70 is located on the load side of the first circuit board 60, sandwiching the first circuit board 60 between the support 70 and the second housing 11. The junction box 80 is fixed to the abutment 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.

[0121] Thus, the first circuit board 60 is held in the axial direction Ax by the second housing 11 and the support body 70, which serves as a heat sink. Therefore, the size of the axial direction Ax, parallel to the shaft 31 of the motor 30, can be suppressed, and the electric drive unit 1 becomes smaller. The junction box 80 is fixed and supported on the abutment surface 73 of the first side surface 74 of the support body 70. Therefore, even if the junction box 80 is pressed by a fixing member BM such as a threaded member, the stress associated with the pressing will act on the support body 70, thereby reducing the stress acting on the first circuit board 60. As a result, the lifespan of the first circuit board 60 is extended, and the reliability of the electric drive unit 1 is improved.

[0122] The first housing 930 has a tool insertion hole 36H. Furthermore, the motor 30 has a side cover 36 that blocks the tool insertion hole 36H and can be detached from the first housing 930. Thus, by removing or attaching the side cover 36, the motor 30 can be easily connected to or disconnected from the ECU 10.

[0123] The first circuit board 60 has a field-effect transistor TR mounted on its second surface 60B, which is closer to the second housing 11, and capacitors 253 and 256, which are electrolytic capacitors, mounted on its first surface 60A, which is closer to the support 70. Thus, both surfaces of the first circuit board 60 are effectively utilized, and the first circuit board 60 can also be miniaturized in the radial direction.

[0124] The support body 70 has a first top plate 71 covering the capacitor 253, and the magnet 32 ​​is inserted into an axial through hole 76 in the top plate at a position that does not overlap with the capacitor 253. This facilitates cooling of the capacitor 253 through heat conduction to the first top plate 71. Furthermore, the first side surface 74 of the support body 70, which is sized according to the axial direction Ax of the capacitor 253, can be used as a contact surface 73 that abuts against the junction box 80. Additionally, since the magnet 32 ​​is inserted at a position that does not overlap with the capacitor 253, the space radially outer side of the magnet 32 ​​can also be used as a placement area for the capacitor 253. As a result, the axial direction Ax of the electric drive device 1 is reduced.

[0125] There is a step between the first top plate 71 and the second top plate 79. As a result, the support body 70 becomes a heat sink with a minimum volume corresponding to the size of each capacitor 253, 256, which helps to reduce the weight of the electric drive unit 1.

[0126] Figure 12 This is an exploded perspective view showing a structural example of mounting the control board of the embodiment onto the wiring module. For example... Figure 12 As shown, the ECU 10 includes a second circuit board 20 with a control circuit 24, which controls a first power circuit 25A and a second power circuit 25B, each having a field-effect transistor TR. The second circuit board 20 is disposed on the load-opposite 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 of the second housing 11. Thus, both axial surfaces of the second housing 11 are used as heat dissipation surfaces, and the second housing functions as a heat sink.

[0127] The second circuit board 20 is housed in the receiving space 11R provided in the second housing 11. As a result, the size of the electric drive device 1 in the axial direction Ax becomes smaller.

[0128] The motor stator 931 includes a first motor coil wiring 321 connected to the first coil group Gr1 and a second motor coil wiring 322 connected to the second coil group Gr2. Two junction boxes 80 are provided, one 80 and the other 80, positioned to sandwich the support body 70. One junction box 80 electrically connects the first motor coil wiring 321 to the first circuit board 60, and the other junction box 80 electrically connects the second motor coil wiring 322 to the first circuit board 60. Thus, even with redundant motor coil wiring, the radial size of the motor 30 can be suppressed by utilizing multiple sides of the support body 70.

[0129] The second housing 11 and the support 70 are connected by a fixing member B2, such as a threaded member. Therefore, even if the junction box 80 is pressed down by the fixing member B2, the stress associated with the pressing is transmitted to the support 70, the fixing member B2, and the second housing 11. As a result, the stress applied to the first circuit board 60 is further reduced.

[0130] Figure 13A This is a top-view perspective view of the heat sink in the implementation method. Figure 13B This is an explanatory diagram illustrating the positional relationship between the heat dissipation surface of the heat sink and the second circuit board in the embodiment. Figure 13C This is a top perspective view of the second circuit board of the embodiment. Figure 14 This is a top view showing the upper surface of the cover and connector of the second circuit board of the embodiment on which it is mounted. Figure 15 It means Figure 14 A sectional view of the XV-XV section. Figure 16 It means Figure 14 A sectional view of section XVI-XVI. Figure 17 This is an exploded perspective view showing an example of the structure of the cover and connector in the embodiment.

[0131] like Figure 12 As shown, the second circuit board 20 has multiple electronic components mounted on both sides of the substrate body. The substrate body of the second circuit board 20 is a printed circuit board formed of resin or the like. The multiple electronic components mounted on the substrate 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 sockets 61. The circuit board 20 is composed of these multiple electronic components. Figure 6 The control circuit 24 shown.

[0132] The second circuit board 20 has through holes CNTIN1, CNTIN3, and PWCH.

[0133] A heat sink 29 is sandwiched between the power wiring module 90 and the second circuit board 20. The heat sink 29 is made of metal and dissipates heat from the choke coil 91 and capacitor 92 used for noise removal in the power wiring module 90, as well as heat generated on the second circuit board 20.

[0134] like Figure 12 As shown, the heat sink 29 has a first base surface 291 on the side of the second circuit board 20, and a protrusion 292, a heat dissipation surface 293, and a heat dissipation surface 294 protruding from the first base surface 291 toward the second circuit board side. The heat sink 29 has a through hole 29H extending axially through it. A terminal of the connector CNT2 is disposed in the through hole 29H. This prevents the terminal of the connector CNT2 from contacting the heat sink 29 and short-circuiting.

[0135] The protrusion 292 has a frustum shape. The protrusion 292 protrudes toward the second circuit board 20 than the heat dissipation surface 293 and the heat dissipation surface 294.

[0136] like Figure 13A As shown, the heat sink 29 has a second base surface 295 on the side of the power wiring module 90, and recesses 296 and 297 recessed from the second base surface 295 toward the second circuit board side.

[0137] like Figure 12 As shown, the power cabling module 90 will connect to connector CNT2 (see reference). Figure 17 The power supply unit 183 connected to the power supply unit transmits power via power cabling PW (see reference). Figure 2 The power wiring module 90 is connected to the lead frame wiring within the module and transmits power to the first circuit board 60 and the second circuit board 20. The lead frame wiring is formed, for example, from a copper alloy. A choke coil 91 and a capacitor 92 are installed in the power wiring module 90 to remove high-frequency components from the power wiring PW from the power supply device 183. The resin of the power wiring module 90 is, for example, polybutylene terephthalate (PBT).

[0138] The greater the power required to drive the motor, the larger the power wiring within the substrate is, resulting in a larger substrate area. Therefore, it is desirable to reduce the amount of power wiring within the substrate. Because of the lead frame wiring within the power wiring module 90, the area of ​​the power wiring located on the first circuit board 60 can be suppressed. As a result, the area of ​​the first circuit board 60 can be suppressed, and the radial size of the ECU 10 is reduced.

[0139] 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 pass through the cover 40 axially and protrude from the main body of the cover 40.

[0140] The input / output terminals of connector CNT1 are electrically connected by inserting into the through-hole CNTIN1 of the second circuit board 20 through the outside of the power wiring module 90 and the outside of the heat sink 29. Similarly, the input / output terminals of connector CNT3 are electrically connected by inserting into the through-hole CNTIN3 of the second circuit board 20 through the outside of the power wiring module 90 and the outside of the heat sink 29.

[0141] It is provided with a positioning hole 421H recessed relative to the reference surface 490 on the load side of the cover 40 and support protrusions 422, 423, 424 protruding towards the load side.

[0142] The choke coil 91 is inserted into a recess 491 that is recessed into the reference surface 490 on the load side of the cover 40. The bottom surface of the recess 491 serves as a heat dissipation surface for the choke coil 91 and a capacitor 92 by means of a heat dissipation material called TIM (Thermal Interface Material).

[0143] like Figure 12 and Figure 13A As shown, the second base surface 295 is the axially opposite side of the first base surface 291. A choke coil 91 and a 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 the capacitor 92 using a heat-dissipating 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 using a heat-dissipating material called TIM (Thermal Interface Material). Thus, the radiator 29 facilitates cooling of the choke coil 91 used for noise reduction, and the axial size of the electronic control device is reduced.

[0144] 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 on the side opposite to the first surface 90A and is inserted into the second recess 491. Thus, the heat dissipation of both surfaces of the choke coil 91 is improved.

[0145] like Figure 13B and Figure 13CAs shown, integrated circuit 24IC1 and power control integrated circuit 24IC2 are mounted on the second circuit board 20. Furthermore, heat dissipation surface 293 is located at a position overlapping integrated circuit 24IC1 in the axial direction. Additionally, heat dissipation surface 294 is located at a position overlapping integrated circuit 24IC2 in the axial direction. Therefore, the heat generated by integrated circuits 24IC1 and 24IC2 is efficiently transferred to the heat sink 29. Integrated circuit 24IC1 and power control integrated circuit 24IC2 constitute... Figure 6 The control and arithmetic unit 241 (control circuit 24) shown is used because there are two integrated circuits 24IC1 and 24IC2 for power control, as follows: Figure 6 As shown, there are two independent control arithmetic units 241. Even if one control arithmetic unit 241 is not working, the other control arithmetic unit 241 can still function, thus increasing the continuity of function.

[0146] like Figure 13C As shown, the second circuit board 20 has a recess 20H of a size that allows the protrusion 292 to enter at a position opposite to the protrusion 292 of the heat sink 29.

[0147] like Figure 14 As shown, the cover 40 is axially connected to the through holes 131H and 132H (refer to...). Figure 7 The overlapping positions have through holes 401H and 402H. Through hole 401H is a round hole, while through hole 402H is an elongated hole. The cover body has through holes 411H, 412H, and 413H at the positions where it overlaps with the internal threaded parts 141H, 142H, and 143H in the axial direction.

[0148] like Figure 15 As shown, the power wiring module 90 is fastened and fixed to the cover 40 using bolts or other fixing components B6. Figure 15 As shown, the second circuit board 20 is fastened and fixed to the cover 40 using bolts or other fixing components B7. Figure 16 As shown, the heat sink 29 is fastened and fixed to the cover 40 by bolts or other fixing components B8. Thus, the power wiring module 90, the heat sink 29, and the second circuit board 20 are assembled together via the cover 40 to form the upper assembly.

[0149] like Figures 12 to 16 As shown, integrated circuits 24IC1 and 24IC2 face the first base surface 291, while the choke coil 91 and capacitor 92 for noise removal in the power wiring module 90 face the second base surface 295. Therefore, the heat generated by integrated circuits 24IC1 and 24IC2 is transferred to the heat sink 29, suppressing the temperature rise of integrated circuits 24IC1 and 24IC2. Furthermore, the heat generated by the choke coil 91 and capacitor 92 for noise removal is transferred to the heat sink 29.

[0150] like Figure 12 , Figure 15 and Figure 16 As shown, the second circuit board 20, heat sink 29, and power wiring module 90 are assembled onto the cover 40. When viewed axially, the second circuit board 20, heat sink 29, and power wiring module 90 are sized to be disposed inside the outer shape of the cover 40. When the cover 40 is assembled in a manner that blocks the receiving space 11R of the second housing 11, the second circuit board 20, heat sink 29, and power wiring module 90 are received within the receiving space 11R.

[0151] With connector CNT3 (reference) Figure 17 The CAN communication terminals and input / output connectors CNT1 (see reference) are used for CAN communication. Figure 17 The torque sensor 194 connected (refer to) Figure 2 The data input / output terminals are directly connected to the second circuit board 20 without going through the power wiring module 90.

[0152] like Figure 17 As shown, connectors CNT are functionally divided into connector CNT1, connector CNT2, and connector CNT3. Connectors CNT1, CNT2, and CNT3 are mounted on the cover 40 via sealing components CNO1, CNO2, and CNO3, respectively, using O-rings or similar sealing members. Connectors CNT1, CNT2, and CNT3 each have a through hole CNTH extending axially along the Ax direction. The cover 40 has an internal thread 44H. Fixing components B5, such as bolts, pass through the through hole CNTH and are fastened to the internal thread 44H. As a result, connectors CNT1, CNT2, and CNT3 are fixed to the cover 40. The terminals of connectors CNT1, CNT2, and CNT3 pass through the through holes 41H, 42H, and 43H respectively, which are formed axially along the Ax direction in the cover 40, reaching the opposite side of the cover 40.

[0153] The heat sink 29 is sandwiched between the power wiring module 90 and the second circuit board 20. The heat sink 29 is made of metals with high heat dissipation properties such as aluminum and copper, and can dissipate heat from the second circuit board 20, the choke coil 91 and the capacitor 92.

[0154] Figure 18 This is an explanatory diagram showing the fixture for assembling the cover body into the second housing of the embodiment. (Refer to...) Figure 7 , Figure 9 , Figure 18 This will explain the manufacturing method of the electronic control device.

[0155] (Preparation process)

[0156] In the preparation process, the first circuit board 60, the second circuit board 20, the second housing 11, and the cover 40 are prepared.

[0157] (Step 1)

[0158] like Figure 9 As shown, after the preparation process, in the first process, the first circuit board 60 is fixed to the second housing 11 using the fixing member B2. The socket 61 of the inter-board connector is inserted into the first through hole 119, and the socket 61 is disposed inside the first through hole 119.

[0159] (Step 2)

[0160] Prepare Figure 18 The fixture J shown is used to mount the second housing, on which the first circuit board 60 was fixed in the first process. Two pins JP protrude from the fixture J, and each pin JP is inserted into... Figure 7 The through holes 131H and 132H are shown. Here, two pins JP have a length protruding from flanges 131 and 132. The diameters of the through holes 131H and 132H are approximately equal to the diameters of the pins JP. Therefore, the second housing 11 is positioned relative to the fixture J using the pins JP.

[0161] (Step 3)

[0162] like Figure 15 , Figure 16 As shown, after the preparation process, in the third process, the second circuit board 20 is fixed to the cover 40. Figure 19A This is a top view showing the power wiring module of the embodiment opposite to the load. Figure 19B This is a top view showing the load side of the power wiring module in the embodiment. Figure 19C This is a perspective view of the power wiring module in the implementation method.

[0163] Specifically, towards Figure 12 The cover 40 shown is assembled with the power wiring module 90. (As shown...) Figure 19A , Figure 19B and Figure 19C As shown, a cylinder 94 covering the support protrusion 422 is integrally formed on the power wiring module 90. A through hole is provided at the center of the cylinder 94, and a hollow space 94H is provided inside the cylinder 94. The cylinder 94 protrudes from the first surface 90A of the power wiring module 90, but does not protrude from the second surface 90B.

[0164] like Figure 12 , Figure 19A , Figure 19B and Figure 19CAs shown, the power wiring module 90 has a second positioning protrusion 95PU protruding from the first surface 90A and a first positioning protrusion 95PD protruding from the second surface 90B.

[0165] like Figure 12 As shown, the hollow space 94H inside the three cylinders 94 ( Figure 19B Insert the support protrusion 422. Next, insert the two first positioning protrusions 95PD ( Figure 19B , Figure 19C Two positioning holes 421H are inserted to determine the position of the power wiring module 90 relative to the cover 40. This makes it difficult for the power wiring module 90 to contact the power input terminal PWCH1, etc. Figure 15 As shown, bolts and other fixing components B6 penetrate the cylinder 94 and are fastened to the internal thread provided on the top of the support protrusion 422.

[0166] like Figure 12 , Figure 19A As shown, the power wiring module 90 includes a first power terminal 93 and a second power terminal 96 protruding from a first surface 90A. In the power wiring module 90, the resin of the base 97 of both the first power terminal 93 and the second power terminal 96 is thicker than the surrounding portion of the base 97. Therefore, the first power terminal 93 and the second power terminal 96 are less likely to tilt relative to the axial direction.

[0167] like Figure 19A As shown, a through-hole INH for inputting power is formed 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 installed on the cover 40, the power input terminals PWCH1 and PWCH2 are inserted into the through-hole INH. The power input section PWin1 and the power input terminal PWCH1 are electrically connected by brazing and soldering, and the power input section PWin2 and the power input terminal PWCH1 are electrically connected by brazing and soldering. Thus, the connector CNT2 can be electrically connected to the power wiring module 90 while ensuring insulation and suppressing the thickness in the axial direction Ax.

[0168] Next, secure the radiator 29 to the cover 40. For example... Figure 12 As shown, the radiator 29 has a mounting portion 298, a through hole 298H opened along the axial direction Ax in the mounting portion 298, a positioning portion 299, and a through hole 299H opened along the axial direction Ax in the positioning portion 299.

[0169] When the two second positioning protrusions 95PU of the power cabling module 90 are inserted into the two through holes 299H of the heat sink 29, the position of the heat sink 29 relative to the power cabling module 90 is determined. The mounting portion 298 abuts against the support protrusion 424, and the through hole 298H and the internal thread portion 424H of the support protrusion 424 are aligned in a straight line. When Figure 16 The bolt or other fixing member B8 shown is fastened to the internal thread 424H of the support protrusion 424 (see reference). Figure 12 When the cover 40 and the heat sink 29 are fixed, the power input terminals PWCH1 and PWCH2, and power input sections PWin1 and PWin2 are arranged inside the through hole 29H to suppress short circuits between the heat sink 29 and the power wiring.

[0170] Next, the second circuit board 20 is mounted on the power wiring module 90. The second power terminal 96 is inserted into the through hole PWCH for electrical connection. Additionally, the input / output terminals of connector CNT1 are inserted into the through hole CNTIN1 of the second circuit board 20 for electrical connection. Similarly, the input / output terminals of connector CNT3 are inserted into the through hole CNTIN3 of the second circuit board 20 for electrical connection.

[0171] The second circuit board 20 abuts against and is supported by the support protrusion 423. For example... Figure 15 and Figure 16 As shown, a bolt or other fixing member B7 passes through the second circuit board 20 and is fastened to an internal thread provided on the top of the support protrusion 423.

[0172] (Step 4)

[0173] like Figure 18 As shown, after the second and third processes, pins JP protruding from flanges 131 and 132 are made to pass through through holes 401H and 402H of the cover 40. When the cover 40 is brought close to the second housing 11, the plug 62 of the inter-substrate connector approaches the socket 61 exposed from the first through hole 119, and the plug 62 of the inter-substrate connector connects to the socket 61. Similarly, in the through hole PWPH (refer to) of the first circuit board 60 exposed from the second through hole 118... Figure 11 Insert the first power terminal 93 into the housing. Since pin JP restricts the position of the second housing 11 and the cover 40, the through holes 131H and 132H of the second housing 11 and the through holes 401H and 402H of the cover 40 become the positioning references. Therefore, it is easy for operators to assemble the second housing 11 and the cover 40.

[0174] The first power terminal 93 is longer than the second power terminal 96. As a result, power is supplied from the power wiring module 90 to the first circuit board 60 and the second circuit board 20, which are located at different positions in the axial direction Ax.

[0175] (Step 5)

[0176] like Figure 18 As shown, the cover 40 and the second housing 11 are fixed by passing the threaded fastener BT1 through the through holes 411H, 412H, and 413H and fastening it to the internal threads 141H, 142H, and 143H. The inter-board connector is assembled in a manner that allows displacement of the plug 62 relative to the socket 61, but suppresses deviation of the plug 62 relative to the socket 61. The connector mounted on the second circuit board 20 is inserted into the recess 117 provided at the bottom 115. Figure 15 and Figure 16 Electronic components such as capacitors shown 69.

[0177] Figure 20 This is a circuit diagram showing the equivalent circuit of the power wiring module in the implementation method. For example... Figure 19A and Figure 20 As shown, power is received from different power input sections PWin1 and PWin2 using separate first power supply circuits 90R and 90L. The circuits for the choke coil 91 and capacitor 92 are also separately provided in the first power supply circuit 90R and 90L, respectively. Furthermore, noise-removed electrodes branch within the power wiring module 90 into a first power terminal 93 supplying power to the first circuit board 60 and a second power terminal 96 supplying power to the second circuit board 20.

[0178] The first power supply terminal 93 of the first power supply circuit 90R and the first power circuit 25A (refer to) Figure 6 The first power terminal 93 of the second power circuit 90L is connected to the second power circuit 25B (refer to...). Figure 6 )connect.

[0179] The second power supply terminal 96 of the first power supply circuit 90R is connected to a control and arithmetic unit 241 (see reference). Figure 6 The first power supply terminal 93 of the second power supply circuit 90L is connected to another control and arithmetic unit 241 (see reference). Figure 6 )connect.

[0180] Thus, the electric drive device 1 of the embodiment independently receives power from two systems and drives them separately as two systems: the first coil group gr1 and the second coil group Gr2. Therefore, the functionality is more consistent.

[0181] Figure 21 It means Figure 14 A sectional view of a partial section of XXI-XXI. Figure 22 It means Figure 14 A sectional view of a partial section of XXII-XXII. Figure 23 It means Figure 14 A sectional view of a partial section of section XXIII-XXIII. Considering the scenario where the electric drive unit is installed in the chassis of vehicle 101, improved dust and water resistance is required to prevent dust and moisture from entering the housing from the outside. Therefore, as... Figures 21-23 As shown, the inner peripheral surface of the first housing 930 and the outer peripheral surface of the second housing 11 are sealed by a sealing member OR1 (first sealing member). The sealing member OR1 is a so-called O-ring formed of rubber or elastomer. The load-opposite end of the second housing 11 and the load-opposite end of the cover 40 are sealed by a sealing member OR2 (second sealing member). As a result, the airtightness of the electric drive device is improved. If the airtightness is improved, the heat of the electronic components of the first circuit board 60 and the second circuit board 20 is difficult to dissipate to the outside, and it is necessary to suppress the temperature rise inside the electric drive device.

[0182] The support body 70, serving as a radiator, has a shape that extends into the inner side of the first sealing member OR1 when viewed axially. Therefore, the support body 70 can be accommodated inside the first housing 930. The radiator 29 has a shape that extends into the inner side of the second sealing member OR2 when viewed axially. Therefore, the radiator 29 can be accommodated inside the second housing 11. As a result, temperature rise within the electric drive unit is suppressed, and the electric drive unit is miniaturized.

[0183] Here, the support 70 and the heat sink 29 are housed inside the first housing 930 or the second housing 11, thus having a limited volume. 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. Figure 21 As shown, the 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 first heat transfer path HTP1 through the support 70 and the fixing member B2. As a result, the support 70 is less prone to thermal saturation. Additionally, the heat from electronic components mounted on the other side of the first circuit board 60 is transferred to the second housing 11 (heat sink) via a second heat transfer path HTP2.

[0184] like Figure 22 As shown, the heat from the choke coil 91 and capacitor 92 used for noise removal in the power wiring module 90 is dissipated via the third heat transfer path HTP3, which transfers heat to the heat sink 29, and the fourth heat transfer path HTP4, which transfers heat to the cover 40. The heat from the electronic components on one side of the second circuit board 20 is dissipated via the third heat transfer path HTP3, which transfers heat to the heat sink 29 (see reference). Figure 22 The heat from the electronic components on the other side of the second circuit board 20 is transferred to the fifth heat transfer path HTP5, which transfers heat to the second housing 11 (see reference). Figure 23 ).

[0185] In addition, the volume of the cover 40 is made larger than the volume of the radiator 29 to increase the heat capacity of the cover 40. For example... Figure 23 As shown, the heat from the radiator 29 is transferred to the cover 40 via the third heat transfer path HTP3 through the metal fixing member B8 (the second fixing member). As a result, the radiator 29 is less prone to thermal saturation.

[0186] As described above, the electric drive device 1 of this embodiment includes a motor 30 and an ECU 10 located on the load-opposite side of the shaft 31 for driving control of 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 along Ax from the load side toward the load-opposite 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 the motor stator 931 causes the motor rotor 932 to rotate. The first housing 930 internally houses the motor rotor 932 and the motor stator 931. A magnet 32 ​​is provided on the load-opposite side of the shaft 31 for driving control of the motor 30.

[0187] ECU 10 includes a first circuit board 60, a second housing 11, a support 70 serving as a second heat sink, and a junction box 80. A field-effect transistor TR and a rotation angle sensor 31a are mounted on the first circuit board 60. The field-effect transistor TR outputs current to excite either the first motor coil 37 or the second motor coil 38. The rotation angle sensor 31a is positioned on the extension of the axial direction Ax of the shaft 31. The second housing 11 is located on the load-opposite side of the first circuit board 60. The support 70 is located on the load side of the first circuit board 60, sandwiching the first circuit board 60 between the support 70 and the second housing 11. The junction box 80 is fixed to the abutment 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.

[0188] Thus, the first circuit board 60 is sandwiched between the second housing 11 and the support 70, which serves as the second heat sink, along the axial direction Ax. Therefore, the size along the axial direction Ax, parallel to the shaft 31 of the motor 30, can be suppressed, and the electric drive unit 1 becomes smaller. The junction box 80 is fixed and supported on the abutment surface 73 of the first side surface 74 of the support 70. Therefore, even if the junction box 80 is pressed by a fixing member BM such as a threaded member, the stress associated with the pressing will act on the support 70, thereby reducing the stress acting on the first circuit board 60. As a result, the lifespan of the first circuit board 60 is extended, and the reliability of the electric drive unit 1 is improved.

[0189] The first housing 930 has a tool insertion hole 36H. Furthermore, the motor 30 has a side cover 36 that blocks the tool insertion hole 36H and can be detached from the first housing 930. Thus, by removing or attaching the side cover 36, the motor 30 can be easily connected to or disconnected from the ECU 10.

[0190] The first circuit board 60 has a field-effect transistor TR mounted on its second surface 60B, which is closer to the second housing 11, and capacitors 253 and 256, which are electrolytic capacitors, mounted on its first surface 60A, which is closer to the support 70. Thus, both surfaces of the first circuit board 60 are effectively utilized, and the first circuit board 60 can also be miniaturized in the radial direction.

[0191] The support body 70 has a first top plate 71 covering the capacitor 253, and the magnet 32 ​​is inserted into an axial through hole 76 in the top plate at a position that does not overlap with the capacitor 253. This facilitates cooling of the capacitor 253 through heat conduction to the first top plate 71. Furthermore, the first side surface 74 of the support body 70, which is sized according to the axial direction Ax of the capacitor 253, can be used as a contact surface 73 that abuts against the junction box 80. Additionally, since the magnet 32 ​​is inserted at a position that does not overlap with the capacitor 253, the space radially outer side of the magnet 32 ​​can also be used as a placement area for the capacitor 253. As a result, the axial direction Ax of the electric drive device 1 is reduced.

[0192] There is a step between the first top plate 71 and the second top plate 79. As a result, the support body 70 becomes a heat sink with a minimum volume corresponding to the size of each capacitor 253, 256, which helps to reduce the weight of the electric drive unit 1.

[0193] The present invention includes a second circuit board 20 having a control circuit 24 that controls a first power circuit 25A and a second power circuit 25B, each having a field-effect transistor TR. The second circuit board 20 is disposed on the load-opposite side of a 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 second housing 11 with an axial direction Ax. Thus, both axial surfaces of the second housing 11 can be used as heat dissipation surfaces.

[0194] The second circuit board 20 is housed in the recess 11R provided in the second housing 11. As a result, the size of the electric drive device 1 in the axial direction Ax becomes smaller.

[0195] The motor stator 931 includes a first motor coil wiring 321 connected to the first coil group Gr1 and a second motor coil wiring 322 connected to the second coil group Gr2. Two junction boxes 80 are provided, one 80 and the other 80, positioned to sandwich the support body 70. One junction box 80 electrically connects the first motor coil wiring 321 to the first circuit board 60, and the other junction box 80 electrically connects the second motor coil wiring 322 to the first circuit board 60. Thus, even with redundant motor coil wiring, the radial size of the motor 30 can be suppressed by utilizing multiple sides of the support body 70.

[0196] The second housing 11 and the support 70 are connected by a fixing member B2, such as a threaded member. Therefore, even if the junction box 80 is pressed down by the fixing member B2, the stress associated with the pressing is transmitted to the support 70, the fixing member B2, and the second housing 11. As a result, the stress applied to the first circuit board 60 is further reduced.

[0197] 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 extending through the second housing 11 along an axial direction Ax; a cover 40 that covers the second housing 11; and an inter-board connector. The first circuit board 60 is equipped with a plurality of switching elements 252, which are field-effect transistors, and a rotation angle sensor 23a. The plurality of switching elements 252 output current to excite the motor coils, and the rotation angle sensor 23a is disposed on the extension of the axial direction Ax of the shaft 31. The first circuit board is disposed on the load-opposite 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 disposed on the load-opposite side of the second housing 11 and the first circuit board 60 disposed on the load side of the second housing 11, and the inter-board connector is disposed in the first through-hole 119.

[0198] Thus, the inter-board connector ensures the transmission of control signals, and the second heat sink improves the heat dissipation of the first and second circuit boards.

[0199] 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, serving as a heat sink for receiving heat from the electronic components of the first circuit board 60 and the electronic components of the second circuit board 20. A support 70 is located on the load side of the first circuit board 60, serving as a heat sink for receiving heat from the electronic components of the first circuit board 60. A heat sink 29 is located on the opposite load side of the second circuit board 20, receiving heat from the electronic components of the second circuit board 20. A cover 40 covers the opposite 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.

[0200] Therefore, the following components are arranged sequentially in the axial direction: a support 70 serving as a heat sink, a first circuit board 60, a second housing 11 serving as a heat sink, a second circuit board 20, a heat sink 29, a power wiring module 90, and a cover 40. As a result, the volume inside the housing can be reduced, the airtightness inside the housing can be improved, and the temperature rise inside the housing can be suppressed.

[0201] ECU 10 includes: a first circuit board 60; a second circuit board 20; a second housing 11 that houses the second circuit board 20; a metal cover 40 that covers the second housing 11; a connector CNT2 having power input terminals PWCH1 and PWCH2 penetrating the cover 40; a power wiring module 90; and a heat sink 29. The first circuit board 60 is equipped with a plurality of switching elements 252, which are field-effect transistors, and a rotation angle sensor 23a. The plurality of switching elements 252 output current to excite the motor coils. The rotation angle sensor 23a is disposed on the extension of the axial direction Ax of the shaft 31. The first circuit board is disposed on the opposite side of the load on 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 from resin using a choke coil 91 and a capacitor 92 for noise reduction, a lead frame wiring that supplies power to the first circuit board 60 and the second circuit board by connecting one end to the power input terminal PWin, a first power terminal connected to the first circuit board, and a second power terminal connected to the second circuit board. The heat sink 29 is sandwiched between the power wiring module 90 and the second circuit board 20, with the power wiring module 90 sandwiched between the heat sink 29 and the cover 40.

[0202] Therefore, the power wiring present in the power wiring module 90 can suppress the area of ​​the power wiring located on the first circuit board 60. As a result, the area of ​​the first circuit board 60 can be suppressed, and the radial size of the ECU 10 becomes smaller. In addition, since the power wiring module 90 is sandwiched between the cover 40 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 can be suppressed.

[0203] Furthermore, the electric power steering system 100 includes the aforementioned electric drive unit 1, which generates auxiliary steering torque. This allows for the suppression of the magnitude of the axial force Ax parallel to the shaft 31 of the motor 30, increasing the flexibility in the configuration of the electric power steering system 100. Because the reliability of the ECU 10 is improved, the reliability of the electric power steering system 100 is also improved.

[0204] Explanation of reference numerals in the attached figures

[0205] 1. Electric drive unit; 10. ECU; 11. Second housing (radiator); 11R. Accommodation space; 12. Sealing member; 20. Second circuit board; 23. Detection circuit; 23a. Rotation angle sensor; 24. Control circuit; 25A. First power circuit; 25B. Second power circuit; 29. ​​Radiator; 30. Motor; 30G. Gear; 31. Shaft; 32. Magnet; 32A. Magnet bracket; 36. Side cover; 36H. Tool insertion hole; 37. First motor cable 38. Second motor coil; 40. Cover; 60. First circuit board; 61. Socket; 62. Plug; 70. Support (heat sink); 90. Power wiring module; 91. Choke coil; 92. Capacitor; 93. First power terminal; 930. First housing (motor housing); 100. Electric power steering; 101. Vehicle; 112. Heat dissipation surface; 113. Recess; 114. Protrusion; 114H. Internal thread; 118. Second through hole; 119. First through hole.

Claims

1. An electric drive device provided with a motor and an electronic control device that controls rotation of the motor, wherein the motor includes: a shaft that extends in an axial direction from a load side toward a side opposite to the load; a motor rotor that is linked to the shaft; a motor stator that has a motor coil and a motor coil wiring for supplying power to the motor coil, the motor stator rotating the motor rotor; a first housing that accommodates the motor rotor and the motor stator on an inner side; and a magnet provided on the side opposite to the load of the shaft, the electronic control device includes: a first circuit board provided on the side opposite to the load of the shaft, the first circuit board mounting a transistor that outputs a current that excites the motor coil and a rotation angle sensor that is disposed on an extension line of the axial direction of the shaft; a first heat sink provided on the side opposite to the load of the first circuit board; a second heat sink provided on the load side of the first circuit board, the first circuit board being sandwiched between the second heat sink and the first heat sink; and a junction box fixed to a side surface of the second heat sink, the junction box electrically connecting the motor coil wiring and the first circuit board, the first housing has a tool insertion hole, the motor is provided with a side cover that plugs the tool insertion hole and is detachable with respect to the first housing, the first circuit board mounts the transistor on the first heat sink side and mounts an electrolytic capacitor on the second heat sink side.

2. The electric drive device according to claim 1, wherein the second heat sink has a top plate that covers the electrolytic capacitor, the magnet is inserted into a through hole in the axial direction that is formed in a position of the top plate that does not overlap the electrolytic capacitor.

3. The electric drive device according to claim 2, wherein the top plate has a step corresponding to the height of a plurality of the electrolytic capacitors.

4. The electric drive device according to any one of claims 1 to 3, wherein the electric drive device has a second circuit board that has a control circuit that controls a power circuit having the transistor, the second circuit board is disposed on the side opposite to the load of the first heat sink and is electrically connected to the first circuit board by a board-to-board connector that is inserted into a through hole in the axial direction that is formed in the first heat sink.

5. The electric drive device according to any one of claims 1 to 3, wherein the electric drive device is further provided with a second circuit board that has a control circuit that controls a current supplied to the transistor, the second circuit board is accommodated in an accommodation space provided in the first heat sink.

6. The electric drive device according to any one of claims 1 to 3, wherein the motor stator is provided with a first motor coil wiring connected to a first coil group and a second motor coil wiring connected to a second coil group. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ One of a terminal block electrically connecting the first motor coil wire and the first circuit substrate and another terminal block electrically connecting the second motor coil wire and the first circuit substrate is disposed at a position sandwiching the second heat sink.

7. The electric drive device according to any one of claims 1 to 3, wherein The first heat sink and the second heat sink are linked by a fixing member.

8. The electric drive device according to claim 5, wherein The electric drive device further comprises: a cover made of metal that covers the first heat sink; a connector having a power supply input terminal that penetrates the cover; and a power supply wiring module that is molded with a choke coil for removing noise, a capacitor, a lead frame wiring that is connected at one end to the power supply input terminal to supply power to the first circuit substrate and the second circuit substrate, a first power supply terminal connected to the first circuit substrate, and a second power supply terminal connected to the second circuit substrate, using resin; and a third heat sink that sandwiches the power supply wiring module between the cover and the third heat sink.

9. The electric drive device according to claim 8, wherein A plurality of first positioning protrusions of the power supply wiring module protrude toward the cover side, and the first positioning protrusions are inserted into positioning holes of the cover.

10. The electric drive device according to claim 8, wherein The third heat sink has a first recess, and the cover has a second recess, A first face of the choke coil protrudes from a first face of the power supply wiring module and is inserted into the first recess, A second face of the choke coil protrudes from a second face of the power supply wiring module on the side opposite the first face of the power supply wiring module and is inserted into the second recess.

11. The electric drive device according to claim 8, wherein The first power supply terminal is longer than the second power supply terminal.

12. The electric drive device according to claim 8, wherein In the power supply wiring module, the resin of the base of both the first power supply terminal and the second power supply terminal is thicker than the portion surrounding the base.

13. The electric drive device according to claim 8, wherein The motor coil includes a first coil system and a second coil system, The first circuit substrate includes a first power circuit that supplies current to the first coil system and a second power circuit that supplies current to the second coil system, The lead frame wiring of the power supply wiring module includes a first power supply circuit and a second power supply circuit, The first power supply terminal of the first power supply circuit is connected to the first power circuit, The first power supply terminal of the second power supply circuit is connected to the second power circuit.

14. The electric drive device according to claim 8, wherein In a space adjacent to a power input portion of the lead frame wiring, a through hole for input power is formed in the resin, The power supply input terminal of the connector that penetrates the cover is inserted into the through hole for input power, and the power input portion and the power supply input terminal are electrically connected.

15. The electric drive device according to claim 8, wherein The third heat sink has a first base surface and a second base surface on the side opposite the first base surface, The second circuit substrate has an integrated circuit, and the integrated circuit is opposite the first base surface, The choke coil and the capacitor for noise removal of the power supply wiring module are opposite the second base surface.

16. The electric drive device according to claim 15, wherein The third heat sink has a heat dissipation surface that protrudes from the first base surface toward the second circuit substrate side, and the heat dissipation surface is positioned at a position overlapping the integrated circuit in the axial direction.

17. An electric power assisted steering device, wherein The electric power assisted steering device includes the electric drive device according to any one of claims 1 to 16, The electric drive device generates an assist steering torque.

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