Electric drive system and electric power steering system

Abstract

To provide an electric drive system and an electric power steering system that stabilize the orientation of the connecting ring and improve reliability. [Solution] The electric drive device comprises a motor and an electronic control device that controls the rotation of the motor. The motor comprises an annular connecting ring and an insulator provided for each tooth. The connecting ring has support legs that protrude toward the motor stator. The insulator has an inner wall, an outer wall radially outward from the inner wall, and a bottom that connects the inner wall and the outer wall and around which a coil is wound. The support legs are inserted into the inner surface of the outer wall of the insulator, and the inner wall of the insulator and the lower surface of the connecting ring body are in contact.

Description

Technical Field

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

Background Art

[0002] An electric power steering device that generates auxiliary steering torque by a motor includes an electronic control device that is a device for controlling the motor (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The electric drive device of Patent Document 1 has an annular connection ring. In the connection ring, a connection conductor is molded with resin. One end of each coil of the motor stator is inserted into the connection ring and drawn out above the connection ring in the axial direction. Then, in the axial direction, there is a connection point where each coil of the motor stator is connected on the upper surface of the connection ring facing a bearing holder called a frame.

[0005] In the electric drive device of Patent Document 1, the connection ring is only placed on the insulator, and the position of the connection ring may not be stable. When a gap occurs between the connection ring and the insulator, foreign matter easily passes from the gap to the rotor side, and the reliability of the electric drive device may decrease.

[0006] The present disclosure has been made in view of the above problems, and an object thereof is to provide an electric drive device and an electric power steering device that improve the reliability by stabilizing the posture of the connection ring. [Means for solving the problem]

[0007] To achieve the above objective, an electric drive device according to one embodiment includes a motor stator that rotates the motor rotor, comprising a shaft extending axially from the load side to the non-load side, a motor rotor interlocked with the shaft, a stator core having a plurality of teeth, an insulator provided for each of the teeth, and a plurality of coils wound around each of the teeth via the insulators, and a motor stator that rotates the motor rotor, and a cylindrical housing that houses the motor rotor and the motor stator inside, an electronic control device for driving and controlling the motor comprising a magnet provided at the non-load end of the shaft, a circuit board positioned on the non-load side of the shaft and on the axial extension of the shaft, a bearing that rotatably supports the shaft, and a cylindrical portion that supports the bearing, between the circuit board and the motor stator The insulator comprises a bearing holder positioned between the circuit board and the coil, and a connecting ring connecting the coil and the bearing holder, the circuit board and the coil, the connecting ring having a connecting conductor having a board connecting portion for connecting to the circuit board, a coil connecting portion for connecting to the coil and a wiring portion for connecting the coil connecting portion and the board connecting portion, an annular connecting ring body formed of an insulating resin with at least a part of the connecting conductor embedded, and support legs that are radially outward from the connecting ring body and protrude toward the motor stator, the insulator having an inner wall, an outer wall radially outward from the inner wall and a bottom portion connecting the inner wall and the outer wall and around which the coil is wound, the support legs are inserted into the inner surface of the outer wall of the insulator and the inner wall of the insulator and the lower surface of the connecting ring body are in contact.

[0008] The support legs stabilize the orientation of the connecting ring. This makes it easier to maintain contact between the inner wall of the insulator and the lower surface of the connecting ring body. As a result, foreign matter is less likely to pass between the connecting ring and the insulator, improving the reliability of the electric drive unit.

[0009] In a preferred embodiment, the outer wall has a position regulating portion that guides the insertion of the support leg into the inner side of the outer wall. This improves assembly workability.

[0010] In a preferred embodiment, the position regulating portion comprises a first guide projection on the inner side of the outer wall and a second guide projection located on the inner side of the outer wall at a circumferentially different position from the first guide projection, and the support leg portion is inserted between the first guide projection and the second guide projection. This improves assembly workability.

[0011] In a preferred embodiment, the outer wall has a contact surface between the first guide projection and the second guide projection that contacts the support leg. This stabilizes the contact state between the support leg and the outer wall.

[0012] In a preferred embodiment, the outer wall has through holes, and the support leg has a claw portion, which is inserted into the through hole in the outer wall. This fixes the support leg to the outer wall.

[0013] In a desirable embodiment, the spacing between adjacent inner walls is smaller than the spacing between adjacent outer walls. This makes it more difficult for foreign objects to pass between adjacent inner walls, thereby improving the reliability of the electric drive device.

[0014] In a preferred embodiment, the electric power steering system includes an electric drive unit, the electric drive unit generating auxiliary steering torque. [Effects of the Invention]

[0015] According to this disclosure, it is possible to provide an electric drive system and an electric power steering system that improve reliability. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 is a schematic perspective view showing a vehicle equipped with an electric power steering system according to Embodiment 1. [Figure 2] Figure 2 is a schematic diagram of an electric power steering apparatus according to Embodiment 1. [Figure 3] Figure 3 is a cross-sectional view schematically showing a cross-section of a motor according to Embodiment 1. [Figure 4] Figure 4 is a schematic diagram showing the wiring of a motor according to Embodiment 1. [Figure 5] Figure 5 is a schematic diagram showing the relationship between a motor and an ECU according to Embodiment 1. [Figure 6] Figure 6 is a side view of an electric drive device according to Embodiment 1. [Figure 7] Figure 7 is a plan view of an electric drive device according to Embodiment 1. [Figure 8] Figure 8 is a perspective view of an electric drive device according to Embodiment 1 with the lid removed. [Figure 9] Figure 9 is a perspective view of the back surface of the lid according to Embodiment 1. [Figure 10] Figure 10 is a plan view of an electric drive device according to Embodiment 1 with the circuit board removed. [Figure 11] Figure 11 is a cross-sectional view showing the cross-section taken along the line XI-XI in Figure 7. [Figure 12] Figure 12 is a cross-sectional view showing the cross-section taken along the line XII-XII in Figure 7. [Figure 13] Figure 13 is a cross-sectional view showing an enlarged partial cross-section of Figure 11. [Figure 14] Figure 14 is a cross-sectional view showing the cross-section taken along the line XIV-XIV in Figure 7. [Figure 15] Figure 15 is a plan view for explaining the mounting state of electronic components on the second surface of the circuit board according to Embodiment 1. [Figure 16] Figure 16 is a plan view for explaining the mounting state of electronic components on the first surface of the circuit board according to Embodiment 1. [Figure 17A] [[ID=​​​​​Figure 18 is a cross-sectional view taken between XVIII and XVIII in Figure 17B. [Figure 19] Figure 19 is a perspective view of the connecting conductor of the connecting ring according to Embodiment 1. [Figure 20] Figure 20 is a cross-sectional view showing the area along the line XX-XX in Figure 7. [Figure 21] Figure 21 is a cross-sectional view showing the line XXI-XXI in Figure 7. [Figure 22] Figure 22 is a view of the support leg portion of Figure 21 from the radially inner side. [Figure 23] Figure 23 is a cross-sectional view taken along the line XXIII-XXIII in Figure 21. [Figure 24] Figure 24 is a cross-sectional view showing a modified example of the support leg shown in Figure 22. [Figure 25] Figure 25 is a cross-sectional view showing the support legs of the modified example shown in Figure 24 fixed to the insulator. [Figure 26] Figure 26 is a plan view of the bearing holder according to Embodiment 1. [Figure 27] Figure 27 is a side view of the bearing holder according to Embodiment 1. [Figure 28] Figure 28 is a schematic diagram of an electric power steering system according to Embodiment 2. [Figure 29] Figure 29 is a schematic diagram of an electric power steering system according to Embodiment 3. [Figure 30] Figure 30 is a schematic diagram of an electric power steering system according to Embodiment 4. [Modes for carrying out the invention]

[0017] Embodiments for implementing this disclosure will be described in detail with reference to the drawings. This disclosure is not limited to the embodiments described below. Furthermore, the components described below include those that are easily conceivable to those skilled in the art, and those that are substantially the same. In addition, the components described below can be combined as appropriate.

[0018] (Embodiment 1) Figure 1 is a schematic perspective view of a vehicle equipped with an electric power steering system according to Embodiment 1. Figure 2 is a schematic diagram of the electric power steering system according to Embodiment 1. As shown in Figure 1, the vehicle 101 is equipped with an electric power steering system 100. The outline of the electric power steering system 100 will be explained with reference to Figure 2.

[0019] As shown in Figure 2, the electric power steering system 100 is a column assist type in which assist force is applied to the output shaft 192B of the steering shaft 192.

[0020] The electric power steering system 100 includes, in the order in which the force applied by the driver (operator) is transmitted, a steering wheel 191, a steering shaft 192, a universal joint 196, an intermediate shaft 197, a universal joint 198, a first rack and pinion mechanism 199, and a tie rod 172. The electric power steering system 100 also includes a torque sensor 194 for detecting the steering torque of the steering shaft 192, a motor 30, an electronic control unit (hereinafter referred to as ECU (Electronic Control Unit)) 10 for controlling the motor 30, and a reduction gear 175. A vehicle speed sensor 182, a power supply unit 183 (e.g., an on-board battery), and an ignition switch 184 are installed in the vehicle body. The vehicle speed sensor 182 detects the driving speed of the vehicle 101. The vehicle speed sensor 182 outputs the detected vehicle speed signal SV to the ECU 10 via CAN (Controller Area Network) communication. When the ignition switch 184 is turned on, power is supplied to the ECU10 from the power supply unit 183 via wiring PW.

[0021] As shown in Figure 2, the steering shaft 192 comprises an input shaft 192A and an output shaft 192B. One end of the input shaft 192A is connected to the steering wheel 191, and the other end is connected to a torsion bar. One end of the output shaft 192B is connected to a torsion bar, and the other end is connected to a universal joint 196. The torque sensor 194 detects the steering torque applied to the steering shaft 192 by detecting the twist of the torsion bar. The torque sensor 194 outputs a steering torque signal T to the ECU 10 corresponding to the detected steering torque. The steering shaft 192 rotates due to the steering force applied to the steering wheel 191.

[0022] The intermediate shaft 197 transmits torque from the output shaft 192B. The first rack and pinion mechanism 199 includes a first pinion shaft 199A, a first pinion gear 199B, a rack shaft 199C, and a first rack 199D. One end of the first pinion shaft 199A is connected to the intermediate shaft 197 via a universal joint 198, and the other end is connected to the first pinion gear 199B. The first rack 199D formed on the rack shaft 199C meshes with the first pinion gear 199B.

[0023] As described above, the rotational motion of the steering shaft 192 is transmitted to the first rack and pinion mechanism 199 via the intermediate shaft 197. This rotational motion is converted into linear motion of the rack shaft 199C by the first rack and pinion mechanism 199. The tie rods 172 are connected to both ends of the rack shaft 199C, respectively.

[0024] Motor 30 is a motor that generates auxiliary steering torque to assist the driver's steering. Motor 30 may be a brushless motor or a brushed motor having brushes and a commutator.

[0025] The ECU 10 is equipped with at least one rotation angle sensor 23a. The rotation angle sensor 23a detects the rotation phase of the motor 30. The ECU 10 obtains the rotation phase signal of the motor 30 from the rotation angle sensor 23a, the steering torque signal T from the torque sensor 194, and the vehicle speed signal SV of the vehicle 101 from the vehicle speed sensor 182. Based on the rotation phase signal, the steering torque signal T, and the vehicle speed signal SV, the ECU 10 calculates an auxiliary steering command value for the assist command. Based on the calculated auxiliary steering command value, the ECU 10 supplies current to the motor 30.

[0026] The electric drive unit 1 comprises a motor 30 and an ECU 10 fixed to the non-load side of the motor 30's shaft. The electric drive unit 1 may also include an adapter connecting the ECU 10 and the motor 30.

[0027] The reduction gear 175 comprises a worm shaft that rotates integrally with the motor shaft 31 of the motor 30, and a worm wheel that meshes with the worm shaft. Therefore, the rotational motion of the motor shaft of the motor 30 is transmitted to the worm wheel via the worm shaft. In Embodiment 1, the end of the motor shaft on the reduction gear 175 side is called the load side end, and the end of the motor shaft on the opposite side of the reduction gear 175 is called the non-load side end.

[0028] The steering force input by the driver to the steering wheel 191 is transmitted to the first rack and pinion mechanism 199 via the steering shaft 192 and the intermediate shaft 197. The first rack and pinion mechanism 199 transmits the transmitted steering force to the rack shaft 199C as a force applied axially to the rack shaft 199C. At this time, the ECU 10 acquires the steering torque signal T input to the steering shaft 192 from the torque sensor 194. The ECU 10 acquires the vehicle speed signal SV from the vehicle speed sensor 182. The ECU 10 acquires the rotation phase signal of the motor 30 from the rotation angle sensor 23a. Then, the ECU 10 outputs a control signal to control the operation of the motor 30. The auxiliary steering torque generated by the motor 30 is transmitted to the output shaft 192B via the reduction gear 175. In this way, the steering of the driver's steering wheel 191 is assisted by the electric power steering system 100.

[0029] Figure 3 is a schematic cross-sectional view showing a cross-section of the motor according to Embodiment 1. Figure 4 is a schematic diagram showing the wiring of the motor according to Embodiment 1. Figure 5 is a schematic diagram showing the relationship between the motor and the ECU according to Embodiment 1. In this Embodiment 1, the circumferential direction is the direction along the concentric circles centered on the shaft 31 shown in Figure 3. The radial direction is the direction away from the shaft 31 in a plane perpendicular to the axial direction AX shown in Figure 3.

[0030] As shown in Figure 3, the motor 30 comprises a housing 930, a motor stator having a stator core 931, and a motor rotor 932. The motor stator includes a cylindrical stator core 931, a plurality of first coils 37, and a plurality of second coils 38. The stator core 931 includes an annular back yoke 931a and a plurality of teeth 931b protruding from the inner circumferential surface of the back yoke 931a. There are 12 teeth 931b arranged in the circumferential direction. The motor rotor 932 includes a rotor yoke 932a and a magnet 932b. The magnet 932b is provided on the outer circumferential surface of the rotor yoke 932a. The number of poles of the magnet 932b is, for example, 12. The rotation of the motor rotor 932 is linked to the rotation of the shaft 31.

[0031] As shown in Figure 3, the first coil 37 is wound around each of the multiple teeth 931b. More specifically, the first coil 37 is wound around the outer circumference of the teeth 931b via an insulator 39. All of the first coils 37 are included in the first coil system. The first coil system according to Embodiment 1 is supplied with current and excited by the first inverter circuit 251A (see Figure 5) included in the first power circuit 25A. The first coil system includes, for example, nine first coils 37. The nine first coils 37 are arranged adjacent to each other in the circumferential direction. Three first coil groups Gr1, each consisting of adjacent first coils 37, are arranged at equal intervals in the circumferential direction. That is, the first coil system has nine slots arranged at equal intervals in the circumferential direction. Note that the first coil groups Gr1 do not necessarily have to be nine; it is sufficient to have 3n coils arranged at equal intervals in the circumferential direction, where n is a natural number. Furthermore, it is preferable that n is an odd number.

[0032] As shown in Figure 3, the second coil 38 is wound around each of the multiple teeth 931b. More specifically, the second coil 38 is wound around the outer circumference of the teeth 931b via an insulator 39. The teeth 931b around which the second coil 38 is wound are different teeth 931b from the teeth 931b around which the first coil 37 is wound. All second coils 38 are included in the second coil system. The second coil system is supplied with current and excited by the second inverter circuit 251B (see Figure 5), which is included in the second power circuit 25B. The second coil system includes, for example, nine second coils 38. The nine second coils 38 are arranged adjacent to each other in the circumferential direction. Three second coil groups Gr2, each consisting of adjacent second coils 38 as a group, are arranged at equal intervals in the circumferential direction. That is, the second coil system has nine slots arranged at equal intervals in the circumferential direction. Note that the second coil group Gr2 does not necessarily have to have 9 slots; it is sufficient if there are 3n slots arranged at equal intervals in the circumferential direction, where n is a natural number. Furthermore, it is preferable that n is an odd number.

[0033] As shown in Figure 3, the gap Δ39P between the inner walls 39P of adjacent insulators 39 is narrower than the gap Δ39Q between the adjacent outer walls 39Q. The gap Δ39P is, for example, a minute gap of several tens of micrometers to several hundred micrometers, which suppresses the passage of foreign matter.

[0034] As described above, in this embodiment 1, there are multiple coil groups, divided into at least two systems, a first coil group Gr1 and a second coil group Gr2, for every three phases, and the stator core is excited with three-phase AC. As a result, even if one coil group fails, the other coil groups can be driven, so the electric drive unit 1 can continue to function.

[0035] As shown in Figure 4, the first coil 37 includes three first U-phase coils 37U, three first V-phase coils 37V, and three first W-phase coils 37W. The first U-phase coils 37U, first V-phase coils 37V, and first W-phase coils 37W are joined in a delta connection.

[0036] As shown in Figure 4, the first coil 37 is excited by the first current I11, the second current I12, and the third current I13 supplied from the first power circuit 25A (see Figure 5).

[0037] As shown in Figure 4, the second coil 38 includes three second U-phase coils 38U, three second V-phase coils 38V, and three second W-phase coils 38W. The second U-phase coils 38U, second V-phase coils 38V, and second W-phase coils 38W are joined in a delta connection.

[0038] As shown in Figure 4, the second coil 38 is excited by the first current I21, the second current I22, and the third current I23 supplied from the second power circuit 25B.

[0039] As shown in Figure 5, the ECU 10 has a circuit board 20 and a connector CNT. The circuit board 20 includes a detection circuit 23, a control circuit 24, a first power circuit 25A, a second power circuit 25B, a power management circuit 27, a power supply circuit 256, a power relay drive circuit 246, a noise filter circuit 90, and a smoothing electrolytic capacitor 253. Note that in Figure 5, circuits that do not require explanation have been omitted as appropriate.

[0040] The control circuit 24 includes a control calculation circuit 241, a first motor drive circuit 26A, a second motor drive circuit 26B, and a cutoff drive circuit 243. Input and output signals such as a steering torque signal T and a vehicle speed signal SV are transmitted to the control calculation circuit 241 via a connector CNT. Since the circuit board 20 is a multilayer resin substrate with multiple conductive layers, the connection wiring that electrically connects the connector CNT to the control calculation circuit 241 of the control circuit 24 is routed through the internal conductive layers of the circuit board 20.

[0041] The wiring PW from the power supply unit 183 (see Figure 2) supplies power via connector CNT. The noise filter circuit 90 has a choke coil 91 and a capacitor 92, and removes high-frequency components superimposed on the power supplied from the wiring PW. The connecting wiring PWS routed to the circuit board 20 connects to the wiring PW from the power supply unit 183. The power that has passed through the noise filter circuit 90 (choke coil 91, capacitor 92) is supplied via the power supply circuit 256 to the first inverter circuit 251A of the first power circuit 25A or the second inverter circuit 251B of the second power circuit 25B. When the first inverter circuit 251A and the second inverter circuit 251B are not distinguished, they will simply be described as inverter circuit 251.

[0042] The power supply circuit 256 is located between the noise filter circuit 90 and the inverter circuit 251. The power supply circuit 256 includes a power cutoff element 257 and a reverse polarity protection element 258. The power cutoff element 257 and the reverse polarity protection element 258 are field-effect transistors (FETs). The forward direction of the parasitic diode of the reverse polarity protection element 258 is opposite to the forward direction of the parasitic diode of the power cutoff element 257. Therefore, even if power of the wrong polarity is mistakenly supplied from the power supply unit 183 (see Figure 2), the reverse polarity protection element 258 cuts off the power of the wrong polarity, protecting the inverter circuit 251.

[0043] The power management circuit 27 is a switching IC that controls the ON / OFF state and power distribution of the circuits mounted on the circuit board 20. For example, the power management circuit 27 controls the distribution of power used by the control circuit 24. One end of the connection wiring is connected to the noise filter circuit 90 (choke coil 91, capacitor 92), and the other end of the connection wiring is connected to the power management circuit 27.

[0044] The first power circuit 25A includes a first inverter circuit 251A and a current interruption circuit 255. The second power circuit 25B includes a second inverter circuit 251B and a current interruption circuit 255.

[0045] The first motor drive circuit 26A includes a first gate drive circuit 242a, a plurality of current detection circuits 244, and a boost circuit 245. The second motor drive circuit 26B includes a second gate drive circuit 242b, a plurality of current detection circuits 244, and a boost circuit 245. The boost circuit 245 supplies boosted power to the first gate drive circuit 242a, the second gate drive circuit 242b, the interruption drive circuit 243, and the power relay drive circuit 246.

[0046] Based on the control of the control calculation circuit 241, the power relay drive circuit 246 activates the power cut-off element 257 and the reverse connection protection element 258, thereby supplying power from the power supply unit 183 (see Figure 2) to each inverter circuit 251.

[0047] The inverter circuit 251 also has multiple drive elements 252. The drive elements 252 are field-effect transistors (FETs), also known as switching elements. The drive elements 252 connected to the high-potential side constitute the upper arm, and the drive elements 252 connected to the low-potential side constitute the lower arm. A shunt resistor SR is connected to each of the three drive elements 252 of the lower arm. Although one shunt resistor SR is connected to each of the three drive elements 252, it is also possible to connect only one shunt resistor SR to all three drive elements 252.

[0048] The control calculation circuit 241 controls either the first motor drive circuit 26A or the second motor drive circuit 26B. For example, the control calculation circuit 241 calculates a motor current command value and controls either the first motor drive circuit 26A or the second motor drive circuit 26B using that motor current command value.

[0049] The first gate drive circuit 242a controls the first power circuit 25A based on the motor current command value. The second gate drive circuit 242b controls the second power circuit 25B based on the motor current command value. In this way, the current flowing to the first coil 37 and the current flowing to the second coil 38 are independently controlled by the control calculation circuit 241.

[0050] The detection circuit 23 includes two rotation angle sensors 23a and a sensor control unit 23b. The detection circuit 23 can continue to function even if one of the rotation angle sensors 23a fails.

[0051] The rotation angle sensor 23a is, for example, a magnetic sensor. The value detected by the rotation angle sensor 23a is supplied to the sensor control unit 23b. The sensor control unit 23b calculates the motor electrical angle θm based on the value detected by the rotation angle sensor 23a and outputs it to the control calculation circuit 241. Alternatively, the control calculation circuit 241 may calculate the motor electrical angle θm based on the output from the sensor control unit 23b.

[0052] The control calculation circuit 241 receives the steering torque signal T detected by the torque sensor 194 (see Figure 2), the vehicle speed signal SV detected by the vehicle speed sensor 82 (see Figure 2), and the motor electrical angle θm as inputs. Based on the steering torque signal T, the vehicle speed signal SV, and the motor electrical angle θm, the control calculation circuit 241 calculates the motor current command value and outputs it to the first gate drive circuit 242a and the second gate drive circuit b.

[0053] The first gate drive circuit 242a calculates a first pulse width modulation signal based on the motor current command value and outputs the gate drive signal to the first inverter circuit 251A of the first power circuit 25A. The gate drive signal is a pulse signal generated based on the gate voltage boosted by the boost circuit 245. The first inverter circuit 251A switches the drive element 252 to obtain three phase current values ​​according to the duty cycle of the first pulse width modulation signal, generating a three-phase AC including a first current I11, a second current I12, and a third current I13 (see Figure 4).

[0054] The second gate drive circuit 242b calculates a second pulse width modulation signal based on the motor current command value and outputs a gate drive signal to the second inverter circuit 251B of the second power circuit 25B. The gate drive signal is generated based on the voltage boosted by the boost circuit 245. The second inverter circuit 251B switches the drive element 252 to obtain three phase current values ​​according to the duty cycle of the second pulse width modulation signal, generating a three-phase AC including a first current I21, a second current I22, and a third current I23 (see Figure 4).

[0055] The inverter circuit 251 is a power conversion circuit that converts DC power to AC power. As described above, the inverter circuit 251 has a plurality of driving elements 252. The driving elements 252 are, for example, field-effect transistors. Smoothing electrolytic capacitors 253 are connected in parallel to the inverter circuit 251. In other words, the circuit board 20 has a plurality of electrolytic capacitors 253 (four electrolytic capacitors 253 in Embodiment 1) connected in parallel.

[0056] Furthermore, the current detection circuit 244 is connected to, for example, a shunt resistor SR. The shunt resistor SR is an example of a current detection element. The current detection element may also be a Hall element or the like. The current detection circuit 244 includes a differential amplifier circuit and a low-pass filter using an operational amplifier. The differential amplifier circuit of the current detection circuit 244 amplifies the detected value detected by the shunt resistor SR, attenuates components higher than the cutoff frequency of the amplified detected value through the low-pass filter, and sends the detected value detected by the shunt resistor SR as a current value to the control calculation circuit 241.

[0057] One current interruption circuit 255 is located between the first inverter circuit 251A and the first coil 37. If the current value detected by the current detection circuit 244 is determined to be abnormal, the control calculation circuit 241 drives the current interruption circuit 255 via the interruption drive circuit 243 to interrupt the current flowing from the first inverter circuit 251A to the first coil 37. The other current interruption circuit 255 is located between the second inverter circuit 251B and the second coil 38. The control calculation circuit 241 drives the current interruption circuit 255 via the interruption drive circuit 243 to interrupt the current flowing from the second inverter circuit 251B to the second coil 38. If the current value detected by the current detection circuit 244 is determined to be abnormal, the control calculation circuit 241 deactivates the power supply interruption element 257 and the reverse connection protection element 258 via the power supply relay drive circuit 246 to protect the inverter circuit 251.

[0058] Figure 6 is a side view of the electric drive device according to Embodiment 1. Figure 7 is a top view of the electric drive device according to Embodiment 1. Figure 8 is a perspective view of the electric drive device according to Embodiment 1 with the cover removed. Figure 9 is a perspective view of the back surface of the cover according to Embodiment 1. Figure 10 is a top view of the electric drive device according to Embodiment 1 with the circuit board removed. Figure 11 is a cross-sectional view showing the view from arrow XI-XI in Figure 7. Figure 12 is a cross-sectional view showing the view from arrow XII-XII in Figure 7. Figure 13 is a cross-sectional view showing an enlarged partial cross-section of Figure 11. Figure 14 is a cross-sectional view showing the view from arrow XIV-XIV in Figure 7. As shown in Figure 6, the electric drive device 1 includes a motor 30 and an ECU 10 located on the non-load side of the motor 30.

[0059] The motor 30 rotates the shaft 31. As shown in Figures 6 and 11, the other end of the shaft 31 has a motor gear 31G that transmits rotation to the worm shaft of the reduction gear 175 (see Figure 2). The end with the motor gear 31G is the load-side end of the shaft 31. The shaft 31 extends axially AX from the load side to the non-load side.

[0060] As shown in Figures 6 and 7, the ECU 10 comprises a flange portion 40 and a cover 50 that covers the non-load side of the motor 30. As shown in Figures 6 and 7, the cover 50 is fixed by being sandwiched between the flange portion 40 and the head of a bolt CT, which is a fixing member. As shown in Figure 11, the flange portion 40 protrudes radially outward from the inner wall of the housing 930. In this embodiment, the flange portion 40 is integrally formed with the housing 930, but it is also possible for the flange portion 40 to be a separate component from the housing 930, and for the flange portion 40 and the housing 930 to be fixed together with bolts or the like.

[0061] As shown in Figure 6, a connector CNT is attached to the load side of the flange portion 40. The connector CNT is electrically connected to the circuit board 20. The connector CNT has terminal CNTP which includes a power terminal, a communication terminal for CAN communication, and an input / output terminal for inputting and outputting data by means other than CAN communication. The resin material of the connector CNT is, for example, polybutylene terephthalate (PBT). Terminal CNTP of the connector CNT is electrically connected to the circuit board 20 (see Figure 8).

[0062] As shown in Figure 8, the flange portion 40 supports the circuit board 20 via the bearing holder 60 and the bolt BT1.

[0063] The bolt BT2, which is a fixing member as shown in Figures 8 and 10, passes through the positioning portion 69 of the bearing holder 60 shown in Figure 10 and fastens to the female threaded portion (not shown) drilled in the flange portion 40. As a result, the bearing holder 60 is fixed in place by being sandwiched between the flange portion 40 and the head of the bolt BT2.

[0064] As shown in Figure 8, the flange portion 40 has a base portion 41, a flange upper surface 41F (first surface), a groove portion 42, three position regulating portions 43, and a protruding portion 45. The flange upper surface 41F (first surface), the groove portion 42, and the protruding portion 45 are each annular and are arranged to surround the outside of the circuit board 20 and the bearing holder 60. The protruding portion 45, the groove portion 42, and the flange upper surface 41F (first surface) are arranged from the radially inner to the radially outer. Also, as shown in Figure 10, each of the three position regulating portions 43 has an internal thread 44 in the axial direction AX.

[0065] As shown in Figure 8, the projection 45 is an annular wall that protrudes from the base 41 toward the non-load side. As shown in Figure 11, the top of the projection 45 toward the non-load side is a plane perpendicular to the axial direction AX.

[0066] As shown in Figures 10 and 11, the size of the bearing holder 60, viewed from the axial direction AX, is such that it fits inside the support portion 52 of the cover 50. As shown in Figure 11, the edge of the bearing holder 60 rests on the upper surface of the protruding portion 45. This eliminates the need to seal the space between the bearing holder 60 and the cover 50, and between the bearing holder 60 and the flange portion 40. In the electric drive device 1 of Embodiment 1, it is sufficient to seal the space between the upper surface 41F of the flange and the edge portion 51 of the cover 50.

[0067] As shown in Figure 13, the upper flange surface 41F is the opposing surface to the lower edge surface 51F (second surface) of the edge 51 of the cover 50. The upper flange surface 41F is a plane perpendicular to the axial direction AX. For most of the upper flange surface 41F, the radial length of the upper flange surface 41F is greater than the radial length of the top of the projection 45 on the non-load side.

[0068] As shown in Figure 14, the groove 42 is provided between the upper flange surface 41F and the protruding portion 45, and between the position regulating portion 43 and the protruding portion 45, and is an annular recess that is recessed below the upper flange surface 41F.

[0069] As shown in Figure 8, the position restricting portion 43 is an island-shaped portion that protrudes from the upper surface 41F of the flange. There may be multiple position restricting portions 43, and they are not limited to three. As shown in Figure 14, the top of the position restricting portion 43 on the non-load side is a plane perpendicular to the axial direction AX. The distance from the upper surface 41F of the flange is smaller for the top of the position restricting portion 43 on the non-load side than for the top of the protruding portion 45 on the non-load side.

[0070] As described above, the bearing holder 60 supports the circuit board 20. As shown in Figures 11 and 12, the circuit board 20 is fixed to one side (the non-load side) of the bearing holder 60. The bearing holder 60 is made of a metal material such as aluminum or copper, which has high heat dissipation properties, and the bearing holder 60 also functions as a heat sink that transfers the heat generated by the electronic components mounted on the circuit board 20 to the flange portion 40.

[0071] For example, as shown in Figure 10, the first recess 63H, the second recess 64H, and the third recess 65H are recessed more than the non-loaded surface of the first base 61 of the bearing holder 60. The first recess 63H is an arc-shaped recess in its longitudinal direction when viewed in the axial direction AX. As shown in Figures 10 and 11, the bearing holder 60 has a through hole 67H that penetrates in the axial direction AX. As shown in Figure 11, the bearing holder 60 has a through hole 60H that penetrates in the axial direction AX. The shaft 31 is inserted into the through hole 60H.

[0072] As shown in Figure 10, an electrolytic capacitor 253 mounted on the first surface 21b of the circuit board 20 is inserted into the first recess 63H of the bearing holder 60. As shown in Figure 11, a heat dissipation material TM is applied between the circuit board 20 and the second base portion 62 (second heat receiving surface) of the first recess 63H of the bearing holder 60. The heat dissipation material TM is, for example, a material made by mixing a thermally conductive filler with a silicone polymer, and is called TIM (Thermal Interface Material). The heat dissipation material TM may be any material other than the above material, as long as it has a higher thermal conductivity than the substrate body 21 of the circuit board 20. The ends of the second electronic components other than the drive element 252 (for example, the electrolytic capacitor 253) are inserted inside the first recess 63H. The heat generated by the electrolytic capacitor 253 is transmitted to the bearing holder 60 via the heat dissipation material TM, and the heat generation of the electrolytic capacitor 253 is suppressed.

[0073] For example, the heat dissipation material TM is placed on the second base portion 62, which is the bottom surface (second heat receiving surface) of the first recess 63H, to a depth that can cool more than 1 / 4 of the axial length AX of the electrolytic capacitor 253. As a result, even if there are manufacturing errors in the axial length AX and outer diameter of the electrolytic capacitor 253, manufacturing errors in the thickness of the circuit board body 21 of the circuit board 20, and assembly errors, the heat dissipation material TM can be interposed between the electrolytic capacitor 253 and the second base portion 62.

[0074] As shown in Figure 10, the second recess 64H is an extension of the first recess 63H, recessed from the non-load side surface of the first base 61 of the bearing holder 60 toward the load side, and has an arc shape in its longitudinal direction. No electrolytic capacitor 253 is inserted into the second recess 64H. The second recess 64H reduces the volume of the first base 61 and contributes to the weight reduction of the electric drive unit 1.

[0075] As shown in Figure 10, the third recess 65H is on the extension of the first recess 63H and is located between the first recess 63H and the second recess 64H. The third recess 65H is recessed from the non-load side surface of the first base 61 of the bearing holder 60 toward the load side, and its longitudinal direction is arc-shaped. No electrolytic capacitor 253 is inserted into the third recess 65H. The third recess 65H reduces the volume of the first base 61 and contributes to the weight reduction of the electric drive unit 1.

[0076] As shown in Figure 10, there is a thickened portion 61A between the first recess 63H and the second recess 64H. There is a thickened portion 61B between the second recess 64H and the third recess 65H. There is a thickened portion 61C between the third recess 65H and the first recess 63H. The thickened portions 61A, 61B, and 61C are thicker than the first recess 63H, the second recess 64H, and the third recess 65H. The presence of the thickened portions 61A, 61B, and 61C ensures the overall rigidity of the bearing holder 60, even with the provision of the first recess 63H, the second recess 64H, and the third recess 65H, allowing the bearing holder 60 to accurately support the bearing 33.

[0077] As shown in Figure 11, the shaft 31 is rotatably supported by bearings 33 and 34. Bearing 33 is interposed between the cylindrical portion 68 of the bearing holder 60 and the shaft 31. The bearing 33 is positioned inside the cylindrical portion 68. The inner ring of bearing 33 is press-fitted and fixed onto the inner ring of shaft 31. A wave washer 68W is interposed between the outer ring of bearing 33 and the bearing holder 60, and the wave washer 68W provides preload to bearing 33. Bearing 34 is interposed between the housing 930 and the shaft 31. In this way, the bearing holder 60 supports the outer ring of bearing 33 inside the cylindrical portion 68. The shaft 31 passes through the cylindrical portion 68 in the axial direction AX. As a result, as shown in Figure 10, the magnet 32 ​​and magnet holder 32A are exposed when viewing the bearing holder from the non-load side to the load side.

[0078] The bolt BT1, a fixing member shown in Figure 8, penetrates the circuit board 20 and fastens to the female threaded portion FT1 drilled in the support column shown in Figure 10. The circuit board 20 is fixed by being sandwiched between the support column 66 of the bearing holder 60 and the head of the bolt BT1. As shown in Figure 10, the bearing holder 60 has a protrusion 60L that protrudes on the non-load side from the non-load side surface of the first base portion 61 of the bearing holder 60. As shown in Figure 8, a part of the end face of the circuit board 20 is a stopper portion 20L. When the stopper portion 20L abuts against the protrusion 60L of the bearing holder 60, it becomes easier to position the circuit board 20 relative to the bearing holder 60, and the bolt BT1, when it has penetrated the circuit board 20, can be easily fitted into the female threaded portion FT1 (see Figure 10).

[0079] The cover 50 is made of metal and prevents foreign matter and moisture from entering the inside of the electric drive unit 1. As shown in Figures 9 and 11, the cover 50 has a top plate portion 55 and a support portion 52. As shown in Figure 11, the top plate portion 55 covers the circuit board 20. The support portion 52 is located radially outward from the top plate portion 55 and extends further toward the flange portion 40 than the top plate portion 55, covering the side of the circuit board 20. The edge portion 51 is the end of the support portion 52 facing the flange portion 40.

[0080] The top plate portion 55 has a first heat receiving surface 54 that protrudes toward the load side, a wall portion 53 that surrounds the electronic components, and a storage portion 53R surrounded by the wall portion 53. As shown in Figure 9, the support portion 52 has a through hole 51H that penetrates in the axial direction AX, and as shown in Figure 14, a bolt CT is inserted into the through hole 51H.

[0081] As shown in Figures 9 and 11, the first heat receiving surface 54 faces the circuit board 20 in order to dissipate the heat generated by the circuit board 20. A heat dissipation material TM is applied between the drive element 252 of the circuit board 20 and the first heat receiving surface 54 of the cover 50. The heat generated by the drive element 252 is transferred to the cover 50 via the heat dissipation material TM, thereby suppressing the heat generation of the drive element 252.

[0082] As shown in Figures 9 and 11, the ends of the first electronic components other than the drive element 252 (for example, the electrolytic capacitor 259) are inserted inside the wall portion 53. As shown in Figure 11, a heat dissipation material TM is applied between the circuit board 20 and the bottom surface (third heat receiving surface) of the storage portion 53R. The heat generated by the electrolytic capacitor 259 is transmitted to the lid 50 via the heat dissipation material TM, thereby suppressing the heat generation of the electrolytic capacitor 259.

[0083] The storage section 53R has a ring-shaped wall portion 53 that surrounds the bottom surface (second heat receiving surface) of the storage section 53R and protrudes towards the load side from the bottom surface (second heat receiving surface) of the storage section 53R. This makes it easier to hold the heat dissipation material TM and stabilizes heat dissipation.

[0084] As shown in Figure 8, the circuit board 20 comprises a substrate body 21 and a plurality of electronic components mounted on the substrate body 21. The substrate body 21 is a printed circuit board formed of, for example, resin. The circuit board 20 is a multilayer substrate with a plurality of conductive layers inside, and the circuit board 20 is a double-sided mounting substrate that allows for mounting on both sides. The plurality of electronic components mounted on a single substrate body 21 include, for example, a central processing unit (CPU), an application-specific integrated circuit (ASIC), a field-effect transistor (FET), a magnetic sensor, an electrolytic capacitor, a resistor, a diode, a thermistor, etc. These plurality of electronic components constitute the detection circuit 23, control circuit 24, first power circuit 25A, and second power circuit 25B shown in Figure 5.

[0085] For example, as shown in Figure 8, multiple drive elements 252, a first motor drive circuit 26A, a second motor drive circuit 26B, an electrolytic capacitor 259, a choke coil 91, a capacitor 92, etc. are mounted on the non-load side of the circuit board 20. Note that the electrolytic capacitor 259 is connected to a boost circuit 245 (see Figure 5) to form a switched-capacitor circuit. Here, as shown in Figure 11, the load side of the circuit board 20 is the first surface 21b (the load side) of the board body 21, and the non-load side of the circuit board 20 is the second surface 21a (the non-load side) of the board body 21.

[0086] The detection circuit 23, control circuit 24, first power circuit 25A, and second power circuit 25B shown in Figure 5 are composed of one or more electronic components mounted on the first surface 21b or second surface 21a of the substrate body 21. For example, as shown in Figure 11, the detection circuit 23 is composed of one electronic component mounted on the first surface 21b of the substrate body 21.

[0087] Furthermore, the control circuit 24 shown in Figure 5 is composed of multiple electronic components mounted on the second surface 21a of the main board 21. Also, as shown in Figure 11, the circuit board 20 includes an electrolytic capacitor 253 mounted on the second surface 21a of the main board 21.

[0088] The detection circuit 23 is located on the non-load side of the shaft 31 and is positioned on the extension of the axial direction AX of the magnet 32. The substrate body 21 has a plane perpendicular to the axial direction AX as the mounting surface for the detection circuit 23. The rotation angle sensor 23a (see Figure 5) of the detection circuit 23 is mounted within the detection circuit 23 so as to be able to sense changes in the magnetic field of the magnet 32. It is desirable that the magnet 32 ​​and the rotation angle sensor 23a face each other in the axial direction AX. The rotation angle sensor 23a may be located on the second surface 21a of the substrate body 21, not just the first surface 21b of the substrate body 21, or it may be located on both the first surface 21b and the second surface 21a of the substrate body 21.

[0089] The rotation angle sensor 23a is, for example, a spin valve sensor. A spin valve sensor is an element that can detect changes in the direction of magnetic flux, with a non-magnetic layer sandwiched between a pinned layer of a ferromagnetic material whose magnetization direction is fixed by an antiferromagnetic layer or the like, and a free layer of a ferromagnetic material. Spin valve sensors include GMR (Giant Magneto Resistance) sensors and TMR (Tunnel Magneto Resistance) sensors. Note that the rotation angle sensor 23a can be any sensor capable of detecting the rotation of the magnet 32. The rotation angle sensor 23a may be, for example, an AMR (Anisotropic Magneto Resistance) sensor or a Hall sensor.

[0090] As shown in Figure 8, the electric drive unit 1 includes a first coil wiring 321 connecting a first coil group Gr1 (see Figure 3) to the circuit board 20, and a second coil wiring 322 connecting a second coil group Gr2 (see Figure 3) to the circuit board 20. The first coil wiring 321 and the second coil wiring 322 may be included in the ECU 10 or in the motor 30. The first coil wiring 321 and the second coil wiring 322 pass through a through hole 67H (see Figure 10). Furthermore, as shown in Figure 8, the first coil wiring 321 and the second coil wiring 322 are inserted into the through hole in the circuit board 20, and the circuit board 20 is electrically connected to the first coil wiring 321 and the second coil wiring 322.

[0091] As shown in Figure 8, a connector CNT is attached to the load side of the flange portion 40. The connector CNT includes a first connector terminal PPW for supplying power, a second connector terminal PCN which is a communication terminal for CAN communication, and a third connector terminal PTS which is a communication terminal for inputting and outputting data by means other than CAN communication.

[0092] As shown in Figure 11, the motor 30 includes a housing 930. The motor rotor 932 includes a rotor yoke 932a and a magnet 932b. The magnet 932b is provided on the outer circumferential surface of the rotor yoke 932a. The housing 930 is cylindrical and houses the motor rotor 932, a stator including a plurality of coil groups divided into two systems for every three phases, for example, a first coil group Gr1 and a second coil group Gr2 (see Figure 3), and a shaft 31 inside.

[0093] As shown in Figures 10 and 11, a magnet 32 ​​is attached to one end of the shaft 31 via a magnet holder 32A. The magnet 32 ​​is magnetized with half being the south pole and the other half being the north pole when viewed from the axial direction AX. Alternatively, the magnet 32 ​​may have alternating south and north poles on its outer surface when viewed from the circumferential direction. Because the bearing 33 has high component precision, the axial position AX of the magnet 32 ​​located on the non-load side of the flange portion 40 remains constant. The end with the magnet 32 ​​is the non-load side end of the shaft 31.

[0094] As shown in Figures 11 and 12, an insulator 39 is attached to the stator core 931 of the motor stator, and a coil body 35 is wound around the outer circumference of the insulator 39. The coil body 35 is part of the first coil 37 and the second coil 38 (see Figure 3). A connecting ring 70 is positioned on the outer circumference of the bearing holder 60, beyond the bearing 33, and between the bearing holder 60 and the insulator 39 of the motor stator.

[0095] As shown in Figure 21, the insulator 39 has an inner wall 39P, an outer wall 39Q, and a bottom 39U. The inner wall 39P and the outer wall 39Q protrude from the bottom 39U around which the coil body 35 is wound, and restrict the position of the coil body 35. The bottom 39U is cylindrical into which the teeth 931b (see Figure 3) are inserted, and connects the inner wall 39P and the outer wall 39Q. Thus, the cross-section of the insulator 39 is U-shaped.

[0096] As shown in Figure 12, the connecting ring body 70A of the connecting ring 70 is an annular insulator. The connecting ring body 70A is, for example, PBT. As shown in Figure 12, the connecting ring body 70A includes at least an inner circumferential wall 71, an outer circumferential wall 72, and an intermediate body 73 that connects the inner circumferential wall 71 and the outer circumferential wall 72. As shown in Figure 11, the connecting ring body 70A includes a partition wall 75 and a wall 742, and a recess 745 is formed therein. As shown in Figure 11, there is a gap between the outer circumferential surface 62S of the second base portion 62 and the partition wall 75. This gap is a minute gap of, for example, several tens of micrometers or less, more preferably 5 micrometers or more and 10 micrometers or less.

[0097] As shown in Figure 12, the inner circumference end of the motor stator insulator 39 and the lower surface 71D of the inner circumference wall 71 are in contact, and the connecting ring 70 rests on the insulator 39. The lower surface 71D of the inner circumference wall 71 is on the non-load side in the axial direction AX than the lower surface (load side surface) 33D of the bearing 33. In this way, the bearing 33 protrudes through the load side in the axial direction AX of the connecting ring 70.

[0098] As shown in Figure 12, a groove 62H is provided on the connecting ring 70 side of the bearing holder 60. A portion of the outer peripheral wall 72 of the connecting ring body 70A is inserted into the groove 62H. The portion of the outer peripheral wall 72 is a protrusion that extends axially AX further than the intermediate body 73. By inserting the portion of the outer peripheral wall 72 as a protrusion into the groove 62H, the gap between the inner wall of the groove 62H and the outer peripheral wall 72 is narrowed. This gap is a minute gap, for example, several tens of micrometers or less, more preferably 5 μm to 10 μm. The structure inserted into the groove 62H as a protrusion is a labyrinth seal structure. In addition, the gap between the outer peripheral surface 62S of the second base portion 62 and the partition wall 75 also functions as a seal.

[0099] As shown in Figure 11, when the lid 50 and the flange portion 40 are fitted together, the edge portion 51 is located radially outward of the protrusion 45. As shown in Figure 13, the upper surface 41F of the flange and the lower surface 51F (second surface) of the edge portion 51 of the lid 50 are fixed facing each other and separated by a maximum distance of 49D. The outer side surface 45S of the protrusion 45 and the inner side surface 51S of the edge portion 51 are fixed facing each other and separated by a maximum distance of 45D. The maximum distance 45D is smaller than the maximum distance 49D.

[0100] As shown in Figure 14, the top of the position regulating portion 43 and the lower edge surface 51F (second surface) of the edge portion 51 of the cover 50 are in contact. The height from the upper flange surface 41F to the top of the position regulating portion 43 is distance 43D. The outer side surface 45S of the protruding portion 45 and the inner side surface 51S of the edge portion 51 are facing each other and fixed at a distance of a maximum distance 45D apart. Distance 43D is the same as the maximum distance 49D.

[0101] When the bolt CT is fastened to the female thread 44, the cover 50 and the flange portion 40 are fixed together. As a result, the top of the position restricting portion 43 and the lower edge surface 51F come into contact, restricting the position of the lower edge surface 51F relative to the upper flange surface 41F. Consequently, the distance 43D and the maximum distance 49D become approximately equal, and the maximum distance 49D tends to remain constant around the flange portion 40.

[0102] As shown in Figures 13 and 14, a foam-in-place gasket 49 is filled between the edge portion 51 and the flange portion 40. The foam-in-place gasket 49, also known as a liquid gasket, is a paste-like substance with variable shape when uncured, and when cured, it becomes elastic while fixing its external shape. The cured foam-in-place gasket 49 becomes a sealing material that has waterproof and dustproof properties against external moisture and dust. The cured foam-in-place gasket 49 can suppress the intrusion of moisture and dust.

[0103] The flange portion 40 has a base portion 41, a projection portion 45, a flange upper surface 41F (first surface), a position regulating portion 43, and a groove portion 42. The base portion 41 is the portion that protrudes radially outward from the motor 30. The projection portion 45 protrudes from the base portion 41 toward the non-load side and protrudes in an annular manner when viewed in the axial direction AX. The flange upper surface 41F is provided radially outward from the projection portion 45 and faces the cover 50. The multiple position regulating portions 43 are island-shaped protrusions on the flange upper surface 41F that protrude from the first surface toward the non-load side. The groove portion 42 is provided in an annular manner along the projection portion 45 when viewed in the axial direction, and is provided between the flange upper surface 41F and the projection portion 45 and between the position regulating portion 43 and the projection portion 45, and is a portion that is recessed from the flange upper surface 41F.

[0104] The cover 50 has a top plate portion 55, a support portion 52, and an edge portion 51. The support portion 52 is radially outward of the top plate portion 55 and extends further towards the load than the top plate portion 55. The edge portion 51 is radially outward of the protruding portion 45. The edge portion 51 of the cover 50 has an edge portion lower surface 51F (second surface) facing the flange upper surface 41F, and an edge portion inner surface 51S facing the radially outward side surface 45S of the protruding portion 45. The form-in-place gasket 49 seals the groove portion 42, the space between the flange upper surface 41F and the edge portion lower surface 51F, and the space between the outer side surface 45S of the protruding portion 45 and the inner side surface 51S of the edge portion. The bolt CT fastens the edge portion 51 and the position regulating portion 43 with the edge portion lower surface 51F in contact with the position regulating portion 43.

[0105] This makes it easier to fit the cover 50 onto the flange portion 40. Furthermore, the positioning of the edge 51 of the cover 50 and the flange portion 40 can be achieved in a state where the foam-in-place gasket 49 is less likely to rest on the position-regulating portion 43. As a result, the assembly workability for attaching the cover 50 to the flange portion 40 is improved, and the foam-in-place gasket 49 provides waterproofing to the electric drive unit 1.

[0106] The maximum distance between the outer surface 45S of the protrusion 45 and the inner surface 51S of the edge 51 is 45D, which is smaller than the maximum distance 49D between the upper flange surface 41F and the lower edge surface 51F. As a result, the direction in which the uncured foam-in-place gasket 49 expands is in a direction that provides greater waterproofing.

[0107] Figure 15 is a plan view illustrating the mounting state of electronic components on the second surface of the circuit board according to Embodiment 1. Figure 16 is a plan view illustrating the mounting state of electronic components on the first surface of the circuit board according to Embodiment 1. The first connector terminal PPW (see Figure 8) is electrically connected to the first connection area APW of the circuit board 20 shown in Figures 15 and 16. The second connector terminal PCN (see Figure 8) is electrically connected to the second connection area ACN of the circuit board 20 shown in Figures 15 and 16. The third connector terminal PTS (see Figure 8) is electrically connected to the third connection area ATS of the circuit board 20 shown in Figures 15 and 16.

[0108] As shown in Figures 15 and 16, the main body 21 of the circuit board 20 has a first side 21s1, a second side 21s2, a third side 21s3, and a fourth side 21s4. A portion of the second side 21s2 forms the aforementioned abutment portion 20L.

[0109] As shown in Figure 15, the edge of the fourth side 21s4 contains the first connection area APW, the second connection area ACN, the third connection area ATS, and the power supply circuit area A90. The power supply circuit area A90 contains the power management circuit 27, the choke coil 91 that constitutes the noise filter circuit, and a number of capacitors 92.

[0110] As shown in Figure 15, the edge of the first side 21s1 includes a first system connection area A321 to which the first coil wiring 321 (see Figure 8) is connected, a power supply circuit implementation area A256A where the first system power supply circuit 256 (see Figure 5) is located, a power interruption circuit implementation area A255A where the first system current interruption circuit 255 (see Figure 5) is located, a first inverter circuit implementation area A251A where the first inverter circuit 251A (see Figure 5) is located, and a current element placement area ASRA where the first system shunt resistor SR (see Figure 5) is located.

[0111] As shown in Figure 15, the edge of the second side 21s2 includes a power supply circuit mounting area A256B where the second power supply circuit 256 (see Figure 5) is located, a power interruption circuit mounting area A255B where the second current interruption circuit 255 (see Figure 5) is located, a second inverter circuit mounting area A251B where the second inverter circuit 251B (see Figure 5) is located, and a current element mounting area ASRB where the second shunt resistor SR (see Figure 5) is located.

[0112] As shown in Figure 15, the edge of the third side 21s3 has a second system connection area A322 to which the second coil wiring 322 (see Figure 8) is connected.

[0113] As shown in Figure 15, an electrolytic capacitor 259 and either a first motor drive circuit 26A or a second motor drive circuit 26B are arranged in the central part of the circuit board.

[0114] As shown in Figure 16, the detection circuit 23 is positioned on the extension of the axial direction AX of the shaft 31. Here, on the main body 21 of the circuit board 20, a number of smoothing electrolytic capacitors 253 are arranged along a virtual curve VC centered on a reference point on the extension of the axial direction AX of the shaft 31. The control calculation circuit 241 is positioned on the opposite side of the electrolytic capacitors 253, with the reference point on the extension of the axial direction AX of the shaft 31 in between.

[0115] As shown in Figures 15 and 16, when viewed in the axial direction AX, the multiple electrolytic capacitors 253 are arranged radially inward of the first inverter circuit mounting area A251A and the second inverter circuit mounting area A251B. As a result, the multiple electrolytic capacitors 253 are adjacent to the first inverter circuit 251A and the second inverter circuit 251B, but do not overlap in the axial direction AX. Therefore, the heat generated by the first inverter circuit 251A and the second inverter circuit 251B and the heat generated by the electrolytic capacitors 253 are less likely to overlap.

[0116] As shown in Figure 11, when the circuit board 20 is attached to the bearing holder 60, the top of the electrolytic capacitor 253 is housed in the first recess 63H, as shown in Figures 10 and 11.

[0117] The imaginary line connecting the centers of the first recess 63H, the second recess 64H, and the third recess 65H in the width direction (radial direction) coincides with the curve VC described above. As a result, multiple electrolytic capacitors 253 are housed side by side in the longitudinal direction of the first recess 63H. Since adjacent electrolytic capacitors 253 are spaced apart, their heat is dispersed and does not concentrate.

[0118] As shown in Figure 10, by drawing a first virtual line XVL that passes through a reference point on the extension of the axial direction AX of the shaft 31 and divides the multiple electrolytic capacitors 253 in half, and a second virtual line YVL that is perpendicular to the first virtual line XVL and passes through the reference point on the extension of the axial direction AX of the shaft 31, the arrangement of the multiple electrolytic capacitors 253 can be determined, and the angle between the furthest electrolytic capacitor 253 and the above reference point is 90 degrees or more and less than 180 degrees. As a result, when the circuit board 20 is attached to the bearing holder 60, the electrolytic capacitors 253 are less likely to come into contact with the thickened parts 61A and 61C, improving assembly workability.

[0119] Figure 17A is a perspective view of the connecting ring body according to Embodiment 1. Figure 17B is a side view of the connecting ring body according to Embodiment 1. Figure 18 is a cross-sectional view taken along the line XVIII-XVIII in Figure 17B. Figure 19 is a perspective view of the connecting conductor of the connecting ring according to Embodiment 1. Figure 20 is a cross-sectional view taken along the line XX-XX in Figure 7.

[0120] As shown in Figure 17A, the connecting ring body 70A has an inner circumferential wall 71, an outer circumferential wall 72, an intermediate body 73 connecting the inner circumferential wall 71 and the outer circumferential wall 72, two substrate connection support parts 74 protruding radially outward from the outer circumferential wall 72, and support legs 70S. As shown in Figures 17A and 18, the substrate connection support part 74 has walls 741 and 742. There is a partition wall 75 between the substrate connection support part 74 and the intermediate body 73, separating them. Walls 741 and 742 are U-shaped, and a recess 745 is formed by the partition wall 75 and walls 741 and 742.

[0121] As shown in Figure 11, there is a gap between the through-hole 67H and the reinforcing part 76, which prevents deterioration of the reinforcing part 67. If there is a gap between the through-hole 67H and the reinforcing part 76, foreign matter may enter through the gap, but even if foreign matter passes through the through-hole 67H of the bearing holder 60, the foreign matter will be trapped in the recess 745. As a result, the reliability of the electric drive unit 1 is improved.

[0122] Inside the recess 745 of the substrate connection support portion 74, a reinforcing portion 76 is erected from the support base 743 inside the recess 745 and extends in the axial direction AX. The reinforcing portion 76 has a cylindrical portion 761 and a rib portion 762. The rib portion 762 connects the cylindrical portion 761 and the wall 742 of the recess 745. Here, the reinforcing portion 76 is molded. Since the rib portion 762 connects the cylindrical portion 761 and the wall 742 of the recess 745, it is possible to suppress the tilting of the reinforcing portion 76 that occurs when the resin cools during mold molding.

[0123] As shown in Figure 19, the substrate connection portion 77 is a flat rectangular wire, and the rib portion 762 shown in Figure 18 extends in a direction perpendicular to the long side surface of the flat rectangular wire. The rib portion 762 connects the cylindrical portion 761 and the wall 742 of the recess 745 in a direction that has resistance to tilting in the direction in which the flat rectangular wire is prone to bending. This makes it possible to suppress the tilting of the reinforcing portion 76 that occurs when the resin cools during mold molding.

[0124] As shown in Figure 18, three substrate connection sections 77 are arranged in a row for each system, and each substrate connection section 77 is provided with two rib sections 762 (see Figure 17A). This reduces the weight of the connection ring body 70A, and because multiple rib sections 762 connect to the wall 742 of the recess 745 for each reinforcing section 76, the tilting of the reinforcing section 76 that occurs when the resin cools during molding can be further suppressed.

[0125] As shown in Figure 20, the bearing holder 60 has a first base portion 61 and a second base portion 62. The first base portion 61 is radially outward from the cylindrical portion 68, and the second base portion 62 is positioned between the first base portion 61 and the cylindrical portion 68. In the axial direction AX, the second base portion 62 of the bearing holder 60 is on the load side of the first base portion 61. In the axial direction AX, the first base portion 61 faces the outer peripheral wall 72, and the second base portion 62 faces the intermediate body 73. In the radial direction, the inner peripheral wall 71 faces the cylindrical portion 68. The coil connection portion 70T protrudes radially outward from the outer peripheral wall 72. This ensures insulation between the coil connection portion 70T and the cylindrical portion 68 and secures space for the fusing point 35B.

[0126] Here, it is necessary to minimize the impact of metal dust generated at the fusing point 35B. This metal dust includes fine metal-derived dust generated by friction between the coil connection part 70T and the coil body 35, and fine metal-derived dust that detaches from the fusing point 35B due to aging or other factors after welding the coil connection part 70T and the coil body 35. If this metal dust enters the gap between the motor rotor and the motor stator, it can affect the continued function of the motor 30. Therefore, the fusing point 35B is located in the space surrounded by the flange part 40, which is part of the housing, the bearing holder 60, the outer peripheral wall 72, and the motor stator. As a result, the motor rotor is less likely to be affected by metal dust generated at the fusing point 35B.

[0127] As shown in Figure 17A, there are multiple openings 70TH on the outside of the outer peripheral wall 72. As shown in Figure 17B, the axial positions of the multiple openings 70TH are aligned. As described above, the connecting ring body 70A is an annular insulator. The support legs 70S are connected to the insulator 39 and stabilize the orientation of the connecting ring body 70A relative to the insulator 39.

[0128] The connecting ring 70 shown in Figure 18 is formed by embedding the connecting conductor 70B shown in Figure 19 into the connecting ring body 70A shown in Figure 17A, and then molding it. The connecting conductor 70B is made by pressing, punching, and bending a metal plate such as copper. Two sets of connecting conductors 70B are provided, divided into two systems for each of the three phases. Each set is formed from the same metal plate for each of the three phases, and the coil connection part 70T, the wiring part 79, and the board connection part 77 are integrated into one unit. The three board connection parts 77 then become the first coil wiring 321 (see Figures 8 and 11) that connects the first coil group Gr1 (see Figure 3) to the circuit board 20. The three board connection parts 77 also become the second coil wiring 322 (see Figures 8 and 11) that connects the second coil group Gr2 (see Figure 3) to the circuit board 20.

[0129] The connecting conductor 70B is called a lead frame, and the coil connection portion 70T, the wiring portion 79, and the board connection portion 77 are punched out of a single metal plate and then bent. The upper wiring portion 79 has a bent portion 791 and an extended portion 794. The middle wiring portion 79 has a bent portion 792 and an extended portion 795. The lower wiring portion 79 has a bent portion 793 and an extended portion 796. The axial length of the bent portion 793 is greater than the axial length of the bent portion 792. The axial length of the bent portion 792 is greater than the axial length of the bent portion 791. This allows the axial positions of the extended portions 794, 795, and 796 to be aligned. Furthermore, the radially outward lengths of the extended portions 794, 795, and 796 are the same. Coil connection sections 70T are continuous with the radially outer sides of extension sections 794, 795, and 796, respectively. The connecting conductor 70B is less prone to deformation than a soft conductor such as the enameled wire of the coil body 35.

[0130] As shown in Figure 18, the coil connection portion 70T protrudes radially outward from the opening 70TH shown in Figure 17A. The coil connection portion 70T is U-shaped and curved away from the substrate connection portion 77. This allows one set of connecting conductors 70B to be superimposed on the other set of connecting conductors 70B when rotated around a predetermined reference line. As a result, the number of parts is reduced, and the manufacturing cost of the electric drive device 1 can be suppressed.

[0131] As shown in Figure 20, one end of the coil body 35 extends axially AX from the insulator 39 side. Then, as shown in Figure 18, the coil body 35 is inserted inside the curved coil connection portion 70T. The coil body 35 and the coil connection portion 70T are electrically connected by resistance welding or the like, and the connection portion becomes the fusing point 35B.

[0132] As shown in Figure 18, the multiple fusing points 35B are arranged in the circumferential direction. This ensures spacing between the coil connection points 70T, making it less likely for metal dust and other contaminants generated at one fusing point 35B to affect other adjacent coil connection points 70T. As a result, the reliability of the electric drive unit 1 is improved.

[0133] As shown in Figures 17B and 18, the multiple fusing points 35B are aligned circumferentially and have the same axial position AX, which facilitates electrical connection at the fusing points 35B. The connecting ring 70 is supported by the coil body 35 at the multiple fusing points 35B, and because the multiple fusing points 35B are aligned circumferentially and have the same axial position AX, the support force provided by the coil body 35 is equal, stabilizing the orientation of the connecting ring 70.

[0134] As shown in Figures 12 and 20, the multiple fusing points 35B are aligned in the circumferential direction and have the same axial position AX.

[0135] Figure 21 is a cross-sectional view taken along the line XXI-XXI in Figure 7. Figure 22 is a view of the support leg in Figure 21 from the radially inner side. Figure 23 is a cross-sectional view taken along the line XXIII-XXIII in Figure 21.

[0136] As shown in Figure 21, when the support leg 70S is inserted inside the outer wall 39Q of the insulator 39, it comes into contact with the inner surface 39I of the outer wall 39Q. Then, as described above, the inner wall 39P of the insulator 39 and the lower surface 71D of the inner circumferential wall 71 are in contact and fixed in place. In this way, when the connecting ring body 70A is fixed at the fusing point 35B, the inner wall 39P of the motor stator's insulator 39 and the lower surface 71D of the inner circumferential wall 71 are in contact and fixed in place. As a result, it becomes difficult for metal dust to pass between the connecting ring 70 and the insulator 39. The gap Δ39P of the inner wall 39P shown in Figure 3 is a very small gap, which suppresses the passage of metal dust.

[0137] As shown in Figure 22, the inner surface 39I of the outer wall 39Q has a first guide projection 39A, a second guide projection 39B, and a contact surface 39C. As shown in Figure 23, the first guide projection 39A and the second guide projection 39B protrude radially inward from the insulator body 39M.

[0138] As shown in Figures 22 and 23, the first guide projection 39A and the second guide projection 39B are spaced apart in the circumferential direction. In other words, the second guide projection 39B is positioned at a different location in the circumferential direction from the first guide projection 39A. The first guide projection 39A and the second guide projection 39B extend axially AX (see Figure 20) from the upper end of the outer wall 39Q. There is a contact surface 39C between the first guide projection 39A and the second guide projection 39B. As a result, a groove is formed on the inner surface 39I of the outer wall 39Q by the first guide projection 39A, the second guide projection 39B, and the contact surface 39C.

[0139] As shown in Figure 22, the position of the support leg 70S is restricted by the first guide projection 39A and the second guide projection 39B, and it comes into contact with the contact surface C, which is part of the inner surface 39I of the outer wall 39Q. In this way, the first guide projection 39A and the second guide projection 39B are position-restricting parts that guide the insertion of the support leg 70S into the inner side of the outer wall 39Q of the insulator 39. As a result, the support leg 70S connects with the insulator 39 and stabilizes the position of the connecting ring body 70A relative to the insulator 39. When the position of the connecting ring body 70A relative to the insulator 39 is stabilized, the contact between the inner wall 39P of the insulator 39 and the lower surface 71D of the inner circumferential wall 71 is stabilized, and the passage of metal dust can be suppressed.

[0140] The first guide portion that guides the insertion of the insulator 39 of the support leg 70S into the inner side of the outer wall 39Q is not limited to the first guide projection 39A and the second guide projection 39B, but may also be a groove recessed in the inner surface 39I of the outer wall 39Q.

[0141] Figure 24 is a cross-sectional view showing a modified example of the support leg shown in Figure 22. Figure 25 is a cross-sectional view showing the modified support leg shown in Figure 24 fixed to the insulator. In the modified example of the support leg 70S shown in Figure 22, a claw portion 70P is provided that protrudes radially outward. As shown in Figure 25, the outer wall 39Q has a through hole 39H that penetrates the outer wall 39Q radially. The through hole 39H in the inner surface 39I of the outer wall 39Q is sized to accommodate the claw portion 70P.

[0142] As shown in Figure 25, the outer wall 39Q does not have the first guide projection 39A and the second guide projection 39B. However, as shown in Figure 25, the claw portion 70P protrudes toward the insulator 39, so when the support leg portion 70S is inserted into the inside of the outer wall 39Q of the insulator 39, the claw portion 70P is inserted into the through hole 39H of the outer wall 39Q. This fixes the connecting ring 70 to the insulator 39.

[0143] This makes the position of the connecting ring body 70A relative to the insulator 39 more stable. When the position of the connecting ring body 70A relative to the insulator 39 is stable, the contact between the inner wall 39P of the insulator 39 and the lower surface 71D of the inner peripheral wall 71 is stabilized, and the passage of metal dust can be suppressed.

[0144] Since the radial thickness of the cross-section of the claw portion 70P decreases sequentially from the base to the tip, the claw portion 70P is easy to insert into the through hole 39H of the outer wall 39Q. Furthermore, once the claw portion 70P is inserted into the through hole 39H of the outer wall 39Q, like a barbed needle, the support leg portion 70S is less likely to come off the insulator 39. As a result, a gap is less likely to form between the inner wall 39P of the insulator 39 and the lower surface 71D of the inner circumferential wall 71, thereby suppressing the passage of metal dust.

[0145] Furthermore, the outer wall 39Q shown in Figure 25 may have a first guide projection 39A, a second guide projection 39B, and a contact surface 39C, as shown in Figure 22. As a result, the claw portion 70P is more easily inserted into the through hole 39H of the outer wall 39Q.

[0146] Figure 26 is a plan view of the bearing holder according to Embodiment 1. Figure 26 shows the bearing holder 60 viewed from the load side to the non-load side. Figure 27 is a side view of the bearing holder according to Embodiment 1. As shown in Figure 26, the bearing holder 60 has a through hole 60H that penetrates in the axial direction AX, and the shaft 31 shown in Figure 11 is inserted into the through hole 60H.

[0147] A cylindrical portion 68 is located radially outside the through hole 60H, and the cylindrical portion 68 surrounds the through hole 60H. A second base portion 62 is located radially outside the cylindrical portion 68, and the groove 62H described above is provided on the edge of the second base portion 62.

[0148] The positioning portion 69 has a through hole BH2 that penetrates in the axial direction AX. A bolt BT2, as shown in Figures 8 and 10, is inserted into the through hole BH2. The second base portion 62 has a through hole 67H that penetrates in the axial direction AX. Three board connection portions 77, as shown in Figure 9, are inserted into one of the through holes 67H and connected to the circuit board 20, thereby forming the first coil wiring 321 and the second coil wiring 322.

[0149] As shown in Figure 27, the support column 66 and the cylindrical portion 68 protrude in opposite directions. The protrusion 60L protrudes more than the support column 66.

[0150] As described above, the electric drive device 1 according to Embodiment 1 includes a motor 30 and an ECU 10 provided on the non-load side of the shaft 31 for driving and controlling the motor 30. The ECU 10 includes a magnet 32 ​​at the non-load end of the shaft 31 and a circuit board 20 located on the non-load side of the shaft 31 and on the extension of the axial direction (for example, axial direction AX) of the shaft 31. The circuit board 20 has a detection circuit 23 including a rotation angle sensor 23a for detecting the rotation of the magnet 32 ​​(shaft 31). The rotation angle sensor 23a is a magnetic sensor for detecting the rotation of the magnet 32.

[0151] Furthermore, the electric drive unit 1 includes a bearing 33, a bearing holder 60, and a connecting ring 70. The bearing 33 rotatably supports the shaft 31. The bearing holder 60 is positioned between the circuit board 20 and the motor stator of the motor 30. The connecting ring 70 connects the circuit board 20 and the coil body 35.

[0152] The connecting ring 70 has a connecting conductor 70B having a board connection portion 77 for connecting to the circuit board 20, a coil connection portion 70T for connecting to the coil body 35, and a wiring portion 79 for connecting the coil connection portion 70T and the board connection portion 77, and an annular connecting ring body 70A formed of insulating resin that embeds at least a part of the connecting conductor 70B.

[0153] The bearing holder 60 has a cylindrical portion 68 that supports the bearing 33. Since the cylindrical portion 68 of the bearing holder 60 is inserted into the hollow portion of the connecting ring 70, the axial AX of the ECU 10 is reduced. Furthermore, the fusing point 35B is not on the bearing holder 60 side of the connecting ring 70, but is on the radially outer side of the connecting ring body 70A. Since the multiple fusing points 35B are aligned in the circumferential direction and are at the same axial AX position, electrical connection at the fusing points 35B is facilitated. The connecting ring 70 is supported by the coil body 35 at the multiple fusing points 35B. As a result, the support force supported by the coil body 35 is equalized, and the posture of the connecting ring 70 is stabilized. In addition, the distance required to ensure insulation between the bearing holder 60 and the connecting ring 70 can be reduced. As a result, the axial AX of the electric drive unit 1 is further suppressed.

[0154] A groove 62H is provided at the bottom of the bearing holder 60 on the side facing the connecting ring 70, and a protrusion (the tip of the outer peripheral wall 72) is provided on the bearing holder 60 side of the connecting ring body 70A. The protrusion (the tip of the outer peripheral wall 72) is inserted into the groove 62H, forming a labyrinth seal structure.

[0155] As a result, the labyrinth seal structure prevents the passage of foreign matter in the space between the bearing holder 60 and the connecting ring 70. This reduces the possibility of foreign matter entering the gap between the motor rotor 932 and the motor stator (stator core 931), thereby improving the reliability of the electric drive unit 1.

[0156] Furthermore, since a portion of the outer perimeter wall 72 forms a protrusion that constitutes a labyrinth seal structure, there is no need to provide a separate protrusion, and the connecting ring 70 can be made smaller.

[0157] The coil body 35 is wound around the stator core 931 via an insulator 39 that insulates it from the stator core 931, and the inner wall 39P of the insulator 39 is in contact with the lower surface of the connecting ring body 70A. This separates the space with a gap between the motor rotor 932 and the motor stator (stator core 931) from the space with the fusing point 35B by a labyrinth seal structure. This makes it difficult for foreign matter to pass between the connecting ring 70 and the insulator 39.

[0158] The ECU10 includes a circuit board 20, a metal cover 50 covering the circuit board 20, a foam-in-place gasket 49, and a number of bolts CT for fixing the flange portion 40 and the cover 50.

[0159] The circuit board 20 has a drive element 252 of an inverter circuit 251 that drives the motor stator, and the top plate portion 55 of the cover 50 has a first heat receiving surface 54 that receives heat from the drive element 252 via a heat dissipation material TM. As a result, the heat from the drive element 252, which generates a large amount of heat, is transferred to the metal cover 50, and the temperature rise of the drive element 252 is suppressed.

[0160] The ECU 10 includes a bearing holder 60 that holds a bearing 33 that rotatably supports the shaft 31. The bearing holder 60 is positioned between the motor rotor 932 and the circuit board 20 in the axial direction AX and is fixed to the flange portion 40. The circuit board 20 has a plurality of electrolytic capacitors 253, which are second electronic components other than the drive element 252, on the load-side surface.

[0161] The bearing holder 60 has a bottom surface (second heat receiving surface) of the first recess 63H of the bearing holder 60 that receives heat from the electrolytic capacitor 253 via the heat dissipation material TM. As a result, even if the mounting density of electronic components on the circuit board 20 is increased, the overall heat generation of the circuit board 20 can be suppressed, and the circuit board 20 and the electric drive unit 1 themselves can be miniaturized.

[0162] Multiple electrolytic capacitors 253 are arranged along a curve VC centered on a reference point on the extension of the axial direction AX of the shaft 31, and are housed in a first recess 63H along the curve VC. This makes it less likely for the electrolytic capacitors 253 to come into contact with the bearing holder 60 when the circuit board 20 is attached to the bearing holder 60, improving assembly workability. Furthermore, even if the mounting position of the circuit board 20 is determined by oscillating the circuit board 20 around the reference point on the extension of the axial direction AX of the shaft 31, the electrolytic capacitors 253 are less likely to come into contact with the bearing holder 60, thus improving the degree of freedom in mounting the circuit board 20.

[0163] Furthermore, the electric power steering system 100 is equipped with the aforementioned electric drive unit 1, which generates auxiliary steering torque. This suppresses torque ripple in the motor 30, improving the operability of the electric power steering system 100.

[0164] (Embodiment 2) Figure 28 is a schematic diagram of an electric power steering device according to Embodiment 2. Note that the same reference numerals are used for components that are the same as those described in Embodiments 1 and 2 above, and redundant explanations are omitted.

[0165] As shown in Figure 28, the electric power steering system 100A is a rack-parallel type. The shaft 31 of the motor 30 is connected to the power transmission mechanism 173. The power transmission mechanism 173 has a pulley 176 and a belt 177. The rotation of the belt 177 rotates the nut of the ball screw device 178. This provides an assist force to the rack shaft 199C based on the rotation of the shaft 31 of the motor 30.

[0166] (Embodiment 3) Figure 29 is a schematic diagram of an electric power steering device according to Embodiment 3. Note that the same reference numerals are used for components that are the same as those described in Embodiments 1 and 2 above, and redundant explanations are omitted. The electric power steering device 100B shown in Figure 29 is a pinion assist type that provides auxiliary steering torque to the first pinion shaft 199A. In the electric power steering device 100B, the torque sensor 194 is connected to the first pinion shaft 199A.

[0167] The motor 30 rotates the reduction gear 175 of the worm shaft. The worm wheel of the reduction gear 175 rotates together with the first pinion shaft 199A. As a result, the motor 30 can rotate the first pinion gear 199B. The first pinion gear 199B meshes with the first rack 199D. As a result, the electric drive unit 1 applies assist force to the first rack 199D via the reduction gear 175. The first pinion gear 199B may be orthogonal to the first rack 199D, or it may be obliquely positioned. As described above, the electric power steering device 100B of Embodiment 3 is a single-pinion assist system.

[0168] (Embodiment 4) Figure 30 is a schematic diagram of an electric power steering device according to Embodiment 4. Note that the same reference numerals are used for components that are the same as those described in Embodiments 1 to 3 above, and redundant explanations are omitted. The electric power steering device 100C includes a first pinion shaft 199A and a first pinion gear 199B, as well as an output shaft 192B and a second pinion gear 171B. The electric power steering device 100C is a dual pinion assist system. The torque sensor 194 detects the torque between the pinion shaft 195 and the first pinion gear 199B.

[0169] The motor 30 rotates the reduction gear 175 of the worm shaft. The worm wheel of the reduction gear 175 rotates together with the output shaft 192B. As a result, the motor 30 can rotate the second pinion gear 171B. The second pinion gear 171B meshes with the second rack 171C. As a result, the electric drive unit 1 applies assist force to the second rack 171C via the reduction gear 175. The second pinion gear 171B may be orthogonal to the second rack 171C, or it may be obliquely positioned. The electric power steering device 100C of Embodiment 4 is a dual pinion assist system. [Explanation of symbols]

[0170] 1. Electric drive unit 10 ECU 20 Circuit boards 21 Main board 21a 2nd side 21b 1st page 23 Detection circuit 23a Rotation Angle Sensor 23b Sensor control unit 24 Control circuits 25A First Power Circuit 25B Second Power Circuit 26A First Motor Drive Circuit 26B Second Motor Drive Circuit 27 Power management circuit 30 motors 31 shafts 32 magnets 37. First coil 38. Second coil 40 Flange section 50 Lid 51 Edge 52 Support part 53 Wall 55 Top plate 60 Bearing holder 61 1st base 62 Second base 68 Cylindrical section 70 connecting rings 70A Connection Ring Body 70B Connecting Conductor 70T coil connection 71 Inner wall 72 Outer wall 73 Intermediates 74. PCB connection support section 75 Partition wall 76 Reinforcement section 77 Board connection section 79 Wiring section 100, 100A, 100B, 100C Electric Power Steering System 930 Housing 931 Stator Core 932 Motor Rotor AX Axial direction Gr1 1st Coil Group Gr2 Second Coil Group

Claims

1. A shaft extending axially from the load side to the non-load side, A motor rotor that is linked to the aforementioned shaft, A motor stator comprising a stator core having multiple teeth, an insulator provided for each tooth, and multiple coils wound around each tooth via the insulators, which rotates the motor rotor, A motor including the motor rotor and the motor stator, a cylindrical housing that houses the motor rotor and motor stator inside, To drive and control the motor, a magnet is provided at the non-loaded end of the shaft, An electronic control device including a circuit board located on the non-load side of the shaft and on the extension of the shaft in the axial direction, A bearing that rotatably supports the aforementioned shaft, A bearing holder having a cylindrical portion that supports the bearing, and positioned between the circuit board and the motor stator, The circuit board and the coil are connected by a connecting ring, The connecting ring comprises a connecting conductor having a board connection portion for connecting to the circuit board, a coil connection portion for connecting to the coil, and a wiring portion for connecting the coil connection portion and the board connection portion; an annular connecting ring body formed of an insulating resin with at least a portion of the connecting conductor embedded in it; and support legs that are radially outward from the connecting ring body and protrude toward the motor stator. The insulator has an inner wall, an outer wall radially outward from the inner wall, and a bottom portion that connects the inner wall and the outer wall and around which the coil is wound. The support legs are inserted into the inner surface of the outer wall of the insulator. The inner wall of the insulator and the lower surface of the connecting ring body are in contact. Electric drive system.

2. The outer wall has a position regulating portion that guides the insertion of the support leg into the inner side of the outer wall. The electric drive device according to claim 1.

3. The position regulating portion comprises a first guide projection on the inner side of the outer wall and a second guide projection located on the inner side of the outer wall at a position different in the circumferential direction from the first guide projection. The support leg is inserted between the first guide projection and the second guide projection. The electric drive device according to claim 2.

4. The outer wall has a contact surface between the first guide projection and the second guide projection that contacts the support leg. The electric drive device according to claim 3.

5. The aforementioned outer wall has through holes, The support leg has a claw portion, and the claw portion is inserted into a through hole in the outer wall. The electric drive device according to claim 1.

6. The distance between adjacent inner walls is smaller than the distance between adjacent outer walls. The electric drive device according to claim 1.

7. The electric drive device is provided according to any one of claims 1 to 6, An electric power steering system in which the aforementioned electric drive device generates auxiliary steering torque.

Images