JP6816659B2 - Electric drive device and electric power steering device - Google Patents

Description

The present invention relates to an electric drive device and an electric power steering device including an electronic control device for controlling the rotation of an electric motor.

The electric power steering device that generates auxiliary steering torque by the electric motor includes an electronic control device that is a device that controls the electric motor. For example, Patent Document 1 describes a motor unit capable of suppressing an increase in size of a motor shaft.

Japanese Unexamined Patent Publication No. 2016-163414

Inside the heat sink of Patent Document 1, there is a through hole through which the shaft of the electric motor is passed, and electronic components of the control board are arranged along the axial direction of the shaft. With such a structure, the sensor substrate having the magnetic sensor facing the magnet attached to the counterload side end of the shaft is arranged on the side farther from the control substrate than the electric motor.

Since it is important for the electric motor to be mounted in a state where the shaft is suppressed from swinging, the sensor board and the control board are mounted around the heat sink after the shaft of the electric motor is protected by the heat sink. Therefore, there is a limit to improving the efficiency of the mounting work.

Further, the electric motor is provided with two coils of two systems, and the two coils are controlled independently, and even if one coil becomes unusable due to disconnection or the like, the rotation of the electric motor is caused by the current of the other coil. , It is hoped that it will be continued. Therefore, if there is only one power board, electronic components such as an inverter circuit that easily generate heat are integrated on one power board by the amount of controlling two coils, and heat tends to be concentrated on the power board. Therefore, it is desired to improve the heat dissipation efficiency of the power substrate.

The present invention has been made in view of the above problems, and is an electric drive device and an electric motor capable of improving the efficiency of assembly work, suppressing heat concentration of the power substrate, and increasing the heat dissipation efficiency of the power substrate. It is an object of the present invention to provide a power steering device.

In order to achieve the above object, the electric drive device according to one embodiment includes a shaft, a motor rotor interlocking with the shaft, a motor stator including a stator core for rotating the motor rotor, and at least two first systems for every three phases. An electric motor that is divided into a coil group and a second coil group and includes a plurality of coil groups that excite the stator core with three-phase AC, and a counterload side of the shaft for driving and controlling the electric motor. The electronic control device includes a magnet at the end of the shaft on the opposite load side and a substrate assembly, and the substrate assembly includes a heat sink and the shaft. At least a sensor substrate on the counterload side, which is arranged on an extension of the shaft in the axial direction and mounts a magnetic sensor that detects the rotation of the magnet, and a plurality of electronic components that supply current to the first coil group. A first power board mounted on the radial outer side of the shaft, a second power board on which a plurality of electronic components for supplying current to the second coil group are mounted at least on the radial outer side of the shaft, and the first power board. And a control board for mounting an electronic component for controlling a current supplied by at least one of the second power boards on at least the radial outer side of the shaft, the first power board, the second power board, and the control. The first power board, the second power board, and the control board are assembled to the heat sink so that the board is arranged around an extension line in the axial direction of the shaft, and the first power board, the first power board. The sensor board is assembled to a heat sink so that the sensor board is sandwiched between the two power boards, the control board, and the electric motor in the axial direction, and mounted on the inside of the shaft in the radial direction of the first power board. The electronic component is inserted into the first recess provided in the heat sink, and the electronic component mounted radially inside the shaft in the second power board is inserted into the second recess provided in the heat sink. Then, the substrate assembly is fixed to the counterload side of the electric motor.

As a result, the first power board, the second power board, the control board, and the sensor board are attached to the electric motor by fixing the pre-assembled board assembly to the counterload side of the electric motor. Therefore, the efficiency of the mounting work is improved. Further, since the first power board and the second power board are separated, the heat of the first power board and the heat of the second power board are not easily transferred to each other, and the heat concentration is suppressed. Further, in the first power board, the heat generated by the electronic component mounted radially inside the shaft and in the second power board, the electronic component mounted radially inside the shaft is generated by the bottom of the first recess or the second recess. Conducts to the heat sink through the side end faces. As a result, the heat of the first power substrate and the heat of the second power substrate are easily dissipated. As a result, the heat concentration of the power substrate can be suppressed, and the heat dissipation efficiency of the power substrate can be improved.

As a preferred embodiment, a heat radiating material is interposed between the electronic component inserted into the first recess and the bottom of the first recess, and the electronic component inserted into the second recess and the first recess. A heat radiating material is interposed between the bottom of the two recesses. As a result, the heat dissipation efficiency of the power substrate is increased.

As a preferred embodiment, the first power board is arranged at a position sandwiching the axial extension line of the second power board and the shaft, and the heat sink is provided with a first heat radiation arm portion, a second heat radiation arm portion, and the like. It is provided with a connecting portion for connecting the first heat radiating arm portion and the second heat radiating arm portion, and has a U shape. The first power substrate is attached to the outer side in the radial direction of the first heat radiating arm portion. The second power substrate is attached to the radial outer side of the second heat radiation arm portion, has the first recess on the radial outer side of the first heat radiation arm portion, and is radially outer side of the second heat radiation arm portion. There is the second recess, and there is a space between the radial inside of the first heat radiation arm portion and the radial inside of the second heat radiation arm portion. As a result, even if the operating ratios of the first power board and the second power board are different, the heat transferred to the first heat radiating arm and the heat transferred to the second heat radiating arm are separated by space. It can dissipate heat.

As a preferred embodiment, the control board is attached to the heat sink so as to straddle the first heat radiating arm portion and the second heat radiating arm portion. As a result, it becomes difficult to transfer the heat of the first heat radiating arm portion and the heat of the second heat radiating arm portion to the control board.

In a preferred embodiment, the electronic component mounted on the radial outer side of the shaft of the first power board or the second power board includes a switching element, and the diameter of the shaft of the first power board or the second power board. Electronic components mounted inside the direction include smoothing capacitors. Even in such an embodiment, the influence of heat generation is suppressed.

The electric power steering device according to one aspect includes the above-mentioned electric drive device, and the electric drive device generates auxiliary steering torque. As a result, the electric power steering device improves the efficiency of the assembly work.

According to the present invention, it is possible to provide an electric drive device and an electric power steering device capable of improving the efficiency of assembly work, suppressing heat concentration of the power substrate, and increasing the heat dissipation efficiency of the power substrate.

FIG. 1 is a perspective view schematically showing a vehicle equipped with the electric power steering device of the present embodiment. FIG. 2 is a schematic view of the electric power steering device of the present embodiment. FIG. 3 is a schematic view showing an arrangement example of the ECU of this embodiment. FIG. 4 is a cross-sectional view schematically showing a cross section of the electric motor of the present embodiment. FIG. 5 is a schematic view showing the wiring of the electric motor of the present embodiment. FIG. 6 is a schematic view showing the relationship between the electric motor and the ECU of the present embodiment. FIG. 7 is an exploded perspective view of the ECU of this embodiment. FIG. 8A is a front view of the substrate assembly of the present embodiment. FIG. 8B is a left side view of the substrate assembly of the present embodiment. FIG. 8C is a right side view of the substrate assembly of this embodiment. FIG. 8D is a plan view of the substrate assembly of the present embodiment. FIG. 8E is a bottom view of the substrate assembly of the present embodiment. FIG. 8F is a rear view of the substrate assembly of the present embodiment. FIG. 8G is a cross-sectional view taken along the arrow of VIIIG-VIIIG of FIG. 8B. FIG. 9 is an exploded perspective view of the substrate assembly of the present embodiment. FIG. 10A is a front view of the heat sink of this embodiment. FIG. 10B is a left side view of the heat sink of this embodiment. FIG. 10C is a right side view of the heat sink of this embodiment. FIG. 10D is a plan view of the heat sink of this embodiment. FIG. 10E is a bottom view of the heat sink of this embodiment. FIG. 10F is a rear view of the heat sink of this embodiment. FIG. 11 is an explanatory diagram for explaining the positional relationship between the shaft, the magnet, and the rotation angle sensor of the present embodiment. FIG. 12 is an explanatory diagram for explaining the connection between the motor connection terminal and the coil wiring of the present embodiment. FIG. 13 is an explanatory diagram for explaining the connection between the first power board and the control board of the present embodiment. FIG. 14 is an explanatory diagram for explaining the fixing of the connector of the present embodiment. FIG. 15 is an explanatory diagram for explaining a sealed structure of the connector of the present embodiment.

Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments for carrying out the following inventions (hereinafter referred to as embodiments). Further, the components in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, that is, those in a so-called equal range. Further, the components disclosed in the following embodiments can be appropriately combined.

(Electric power steering device)
FIG. 1 is a perspective view schematically showing a vehicle equipped with the electric power steering device of the present embodiment. FIG. 2 is a schematic view of the electric power steering device of the present embodiment. As shown in FIG. 1, the vehicle 101 is equipped with the electric power steering device 100. The outline of the electric power steering device 100 will be described with reference to FIG.

The electric power steering device 100 includes the steering wheel 91, the steering shaft 92, the universal joint 96, the intermediate shaft 97, the universal joint 98, and the first in the order in which the force given by the driver (operator) is transmitted. It includes a rack and pinion mechanism 99 and a tie rod 72. Further, the electric power steering device 100 includes a torque sensor 94 that detects the steering torque of the steering shaft 92, an electric motor 30, and an electronic control device (hereinafter, referred to as an ECU (Electronic Control Unit)) 10 that controls the electric motor 30. A speed reducing device 75 and a second rack and pinion mechanism 70 are provided. The vehicle speed sensor 82, the power supply device 83 (for example, an in-vehicle battery), and the ignition switch 84 are provided on the vehicle body. The vehicle speed sensor 82 detects the traveling speed of the vehicle 101. The vehicle speed sensor 82 outputs the detected vehicle speed signal SV to the ECU 10 by CAN (Controller Area Network) communication. Electric power is supplied to the ECU 10 from the power supply device 83 with the ignition switch 84 turned on.

The electric drive device 1 includes an electric motor 30 and an ECU 10 fixed to the opposite load side of the shaft 31 of the electric motor 30.

As shown in FIG. 2, the steering shaft 92 includes an input shaft 92A, an output shaft 92B, and a torsion bar 92C. One end of the input shaft 92A is connected to the steering wheel 91 and the other end is connected to the torsion bar 92C. One end of the output shaft 92B is connected to the torsion bar 92C and the other end is connected to the universal joint 96. The torque sensor 94 detects the steering torque applied to the steering shaft 92 by detecting the twist of the torsion bar 92C. The torque sensor 94 outputs a steering torque signal T corresponding to the detected steering torque to the ECU 10 by CAN communication. The steering shaft 92 rotates by the steering force applied to the steering wheel 91.

The intermediate shaft 97 has an upper shaft 97A and a lower shaft 97B, and transmits the torque of the output shaft 92B. The upper shaft 97A is connected to the output shaft 92B via the universal joint 96. On the other hand, the lower shaft 97B is connected to the first pinion shaft 99A of the first rack and pinion mechanism 99 via the universal joint 98. The upper shaft 97A and the lower shaft 97B are, for example, spline-coupled.

The first rack and pinion mechanism 99 includes a first pinion shaft 99A, a first pinion gear 99B, a rack shaft 99C, and a first rack 99D. One end of the first pinion shaft 99A is connected to the lower shaft 97B via a universal joint 98, and the other end is connected to the first pinion gear 99B. The first rack 99D formed on the rack shaft 99C meshes with the first pinion gear 99B. The rotational movement of the steering shaft 92 is transmitted to the first rack and pinion mechanism 99 via the intermediate shaft 97. This rotational motion is converted into a linear motion of the rack shaft 99C by the first rack and pinion mechanism 99. The tie rods 72 are connected to both ends of the rack shaft 99C, respectively.

The electric motor 30 is a motor that generates an auxiliary steering torque for assisting the driver's steering. The electric motor 30 may be a brushless motor or a brush motor having a brush and a commutator.

The ECU 10 includes a rotation angle sensor 23a. The rotation angle sensor 23a detects the rotation phase of the electric motor 30. The ECU 10 acquires the rotation phase signal of the electric motor 30 from the rotation angle sensor 23a, acquires the steering torque signal T from the torque sensor 94, and acquires the vehicle speed signal SV of the vehicle 101 from the vehicle speed sensor 82. The ECU 10 calculates the auxiliary steering command value of the assist command based on the rotation phase signal, the steering torque signal T, and the vehicle speed signal SV. The ECU 10 supplies a current to the electric motor 30 based on the calculated auxiliary steering command value.

The speed reduction device 75 includes a worm shaft 75A that rotates integrally with the shaft 31 of the electric motor 30, and a worm wheel 75B that meshes with the worm shaft 75A. Therefore, the rotational movement of the shaft 31 is transmitted to the worm wheel 75B via the worm shaft 75A. In the present embodiment, the speed reducing device 75 side of the shaft 31 is referred to as a load side end portion, and the side of the shaft 31 opposite to the speed reducing device 75 is referred to as a counterload side end portion.

The second rack and pinion mechanism 70 includes a second pinion shaft 71A, a second pinion gear 71B, and a second rack 71C. The second pinion shaft 71A is fixed so that one end thereof rotates coaxially and integrally with the worm wheel 75B. The other end of the second pinion shaft 71A is connected to the second pinion gear 71B. The second rack 71C formed on the rack shaft 99C meshes with the second pinion gear 71B. The rotational movement of the electric motor 30 is transmitted to the second rack and pinion mechanism 70 via the reduction gear 75. This rotational motion is converted into a linear motion of the rack shaft 99C by the second rack and pinion mechanism 70.

The driver's steering force input to the steering wheel 91 is transmitted to the first rack and pinion mechanism 99 via the steering shaft 92 and the intermediate shaft 97. The first rack and pinion mechanism 99 transmits the transmitted steering force to the rack shaft 99C as a force applied in the axial direction of the rack shaft 99C. At this time, the ECU 10 acquires the steering torque signal T input to the steering shaft 92 from the torque sensor 94. The ECU 10 acquires the vehicle speed signal SV from the vehicle speed sensor 82. The ECU 10 acquires the rotation phase signal of the electric motor 30 from the rotation angle sensor 23a. Then, the ECU 10 outputs a control signal to control the operation of the electric motor 30. The auxiliary steering torque generated by the electric motor 30 is transmitted to the second rack and pinion mechanism 70 via the reduction gear 75. The second rack and pinion mechanism 70 transmits the auxiliary steering torque to the rack shaft 99C as a force applied in the axial direction of the rack shaft 99C. In this way, the steering of the driver's steering wheel 91 is assisted by the electric power steering device 100.

FIG. 3 is a schematic view showing an arrangement example of the ECU of this embodiment. As shown in FIG. 3, the electric drive device 1 including the ECU 10 and the electric motor 30 is arranged in the vicinity of the first rack and pinion mechanism 99 and the second rack and pinion mechanism 70. As described above, the electric power steering device 100 is a rack assist system in which an assist force is applied to the second rack and pinion mechanism 70, but the present invention is not limited to this. The electric power steering device 100 may be, for example, a column assist system in which an assist force is applied to the steering shaft 92 or a pinion assist system in which an assist force is applied to the first pinion gear 99B.

FIG. 4 is a cross-sectional view schematically showing a cross section of the electric motor of the present embodiment. FIG. 5 is a schematic view showing the wiring of the electric motor of the present embodiment. As shown in FIG. 4, the electric motor 30 includes a housing 930, a stator having a stator core 931 and a rotor 932. The 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 peripheral surface of the back yoke 931a. Twelve teeth 931b are arranged in the circumferential direction. The rotor 932 includes a rotor yoke 932a and a magnet 932b. The magnet 932b is provided on the outer peripheral surface of the rotor yoke 932a. The number of magnets 932b is, for example, eight.

As shown in FIG. 4, the first coil 37 is centrally wound around each of the plurality of teeth 931b. The first coil 37 is centrally wound around the outer circumference of the teeth 931b via an insulator. All the first coils 37 are included in the first coil system. The first coil system of the present embodiment is supplied with a current and excited by the inverter circuit 251 (see FIG. 6) of the first power substrate 25A. The first coil system includes, for example, six first coils 37. The six first coils 37 are arranged so that the two first coils 37 are adjacent to each other in the circumferential direction. Three first coil groups Gr1 in which adjacent first coils 37 are grouped are arranged at equal intervals in the circumferential direction. That is, the first coil system includes three first coil groups Gr1 arranged at equal intervals in the circumferential direction. The first coil group Gr1 does not necessarily have to be three, and it is sufficient that three first coil groups Gr1 are arranged at equal intervals in the circumferential direction when n is a natural number. Further, it is desirable that n is an odd number.

As shown in FIG. 4, the second coil 38 is centrally wound around each of the plurality of teeth 931b. The second coil 38 is centrally wound around the outer circumference of the teeth 931b via an insulator. The teeth 931b in which the second coil 38 is centrally wound is a teeth 931b different from the teeth 931b in which the first coil 37 is centrally wound. All the second coils 38 are included in the second coil system. The second coil system is excited by being supplied with a current by the inverter circuit 251 (see FIG. 6) of the second power board 25B. The second coil system includes, for example, six second coils 38. The six second coils 38 are arranged so that the two second coils 38 are adjacent to each other in the circumferential direction. Three second coil groups Gr2, in which adjacent second coils 38 are grouped together, are arranged at equal intervals in the circumferential direction. That is, the second coil system includes three second coil groups Gr2 arranged at equal intervals in the circumferential direction. The number of the second coil groups Gr2 does not necessarily have to be three, and 3n may be arranged at equal intervals in the circumferential direction when n is a natural number. Further, it is desirable that n is an odd number.

As shown in FIG. 5, the six first coils 37 are the two first U phase coils 37Ua and the first U phase coil 37Ub excited by the first U phase current I1u and the two excited by the first V phase current I1v. It includes a first V-phase coil 37Va and a first V-phase coil 37Vb, and two first W-phase coils 37Wa and a first W-phase coil 37Wb excited by a first W-phase current I1w. The 1st U phase coil 37Ub is connected in series with the 1st U phase coil 37Ua. The first V-phase coil 37Vb is connected in series with the first V-phase coil 37Va. The first W phase coil 37Wb is connected in series with the first W phase coil 37Wa. The winding directions of the first coil 37 with respect to the teeth 931b are all the same. Further, the 1st U phase coil 37Ub, the 1st V phase coil 37Vb and the 1st W phase coil 37Wb are joined by a star connection (Y connection).

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

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

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

The first coil 37 excited by the first U-phase current I1u faces the second coil 38 excited by the second U-phase current I2u in the radial direction of the stator core 931. In the following description, the radial direction of the stator core 931 is simply described as the radial direction. For example, as shown in FIG. 4, the first U-phase coil 37Ua faces the second U-phase coil 38Ua in the radial direction, and the first U-phase coil 37Ub faces the second U-phase coil 38Ub.

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

The first coil 37 excited by the first W phase current I1w faces the second coil 38 excited by the second W phase current I2w in the radial direction. For example, as shown in FIG. 4, the first W-phase coil 37Wa faces the second W-phase coil 38Wa and the first W-phase coil 37Wb faces the second W-phase coil 38Wb in the radial direction.

FIG. 6 is a schematic view showing the relationship between the electric motor and the ECU of the present embodiment. As shown in FIG. 6, the ECU 10 includes a control calculation unit 241, a motor rotation angle detection circuit 23, a motor rotation speed calculation unit 22, a gate drive circuit 242, a cutoff drive circuit 243, and an inverter circuit 251. I have.

The control calculation unit 241 calculates the motor current command value. The motor rotation speed calculation unit 22 calculates the motor electric angle θm and outputs it to the control calculation unit 241. The motor current command value output from the control calculation unit 241 is input to the gate drive circuit 242.

As shown in FIG. 6, the electric motor 30 includes a rotation angle sensor 23a. The rotation angle sensor 23a is, for example, a magnetic sensor. The motor rotation angle detection circuit 23 supplies the detection value from the rotation angle sensor 23a to the motor rotation speed calculation unit 22. The motor rotation speed calculation unit 22 calculates the motor electric angle based on the detection value of the rotation angle sensor 23a and outputs it to the control calculation unit 241.

The steering torque signal T detected by the torque sensor 94, the vehicle speed signal SV detected by the vehicle speed sensor 82, and the motor electric angle θm output from the motor rotation speed calculation unit 22 are input to the control calculation unit 241. Will be done. The control calculation unit 241 calculates the motor current command value based on the steering torque signal T, the vehicle speed signal SV, and the motor electric angle θm, and outputs the motor current command value to the gate drive circuit 242.

The gate drive circuit 242 calculates the first pulse width modulation signal based on the current command value and outputs it to the inverter circuit 251 of the first power board 25A. The inverter circuit 251 switches the switching element 252 so as to have a three-phase current value according to the duty ratio of the first pulse width adjustment signal, and the first U phase current I1u, the first V phase current I1v, and the first W phase. Generates a three-phase AC including the current I1w. The 1st U phase current I1u excites the 1st U phase coil 37Ua and the 1st U phase coil 37Ub, the 1st V phase current I1v excites the 1st V phase coil 37V and the 1st V phase coil 37Vb, and the 1st W phase current I1w excites the 1st W. The phase coil 37Wa and the first W phase coil 37Wb are excited.

The gate drive circuit 242 calculates the second pulse width modulation signal based on the current command value and outputs it to the inverter circuit 251 of the second power board 25B. The inverter circuit 251 switches the switching element 252 so as to have a three-phase current value according to the duty ratio of the second pulse width adjustment signal, and the second U phase current I2u, the second V phase current I2v, and the second W phase. Generates a three-phase AC including the current I2w. The second U phase current I2u excites the second U phase coil 38Ua and the second U phase coil 38Ub, the second V phase current I2v excites the second V phase coil 38Va and the second V phase coil 38Vb, and the second W phase current I2w excites the second W. The phase coil 38Wa and the second W phase coil 38Wb are excited.

The inverter circuit 251 includes, for example, a switching element 252 and a smoothing capacitor 253. The switching element 252 is, for example, a field effect transistor. As the smoothing capacitor 253, for example, an electrolytic capacitor is used.

As shown in FIG. 6, the electric power steering device 100 includes a current detection circuit 254 for detecting the current value of each phase of the electric motor 30. For example, the current detection circuit 254 includes a shunt resistor. The current value detected by the current detection circuit 254 is sent to the control calculation unit 241. The current detection circuit 254 may be connected so as to detect the current value of each phase of the electric motor 30.

The current cutoff circuit 255 is arranged between the inverter circuit 251 and the first coil 37 or the second coil 38. When the current value detected by the current detection circuit 254 is determined to be abnormal, the control calculation unit 241 drives the current cutoff circuit 255 via the cutoff drive circuit 243, and the current flowing from the inverter circuit 251 to the first coil 37. Can be blocked. Further, the control calculation unit 241 can drive the current cutoff circuit 255 via the cutoff drive circuit 243 to cut off the current flowing from the inverter circuit 251 to the second coil 38. In this way, the current flowing through the first coil 37 and the current flowing through the second coil 38 are independently controlled by the control calculation unit 241.

Signal transmission wiring for transmitting input / output signals to the control board 24, such as the steering torque signal T and the vehicle speed signal SV, is input to the control calculation unit 241 via the connector CNT. A power wiring PW for transmitting power from the power supply device 83 is connected to at least one of the first power board 25A and the second power board 25B via the connector CNT. In the present embodiment, the power wiring PW from the power supply device 83 is connected to the first power board 25A and the second power board 25B via the connector CNT.

FIG. 7 is an exploded perspective view of the ECU of this embodiment. FIG. 8A is a front view of the substrate assembly of the present embodiment. FIG. 8B is a left side view of the substrate assembly of the present embodiment. FIG. 8C is a right side view of the substrate assembly of this embodiment. FIG. 8D is a plan view of the substrate assembly of the present embodiment. FIG. 8E is a bottom view of the substrate assembly of the present embodiment. FIG. 8F is a rear view of the substrate assembly of the present embodiment. FIG. 8G is a cross-sectional view taken along the arrow of VIIIG-VIIIG of FIG. 8B. FIG. 9 is an exploded perspective view of the substrate assembly of the present embodiment.

As shown in FIG. 7, the ECU 10 includes a substrate assembly 200 and a cover 210. The cover 210 is made of metal or resin. As shown in FIG. 9, in the board assembly 200, the first power board 25A, the second power board 25B, the control board 24, the sensor board 21, and the connector CNT are attached to the five surfaces of the heat sink 40. Has been done.

The first power board 25A, the second power board 25B, the control board 24, and the sensor board 21 are printed circuit boards made of resin or the like.

As shown in FIG. 8A, the control board 24 includes a control calculation unit 241 shown in FIG. 6, an electronic component 245 constituting a gate drive circuit 242 and a cutoff drive circuit 243, and a lead insertion hole 248.

As shown in FIG. 8B, the first power board 25A includes electronic components 256 constituting the inverter circuit 251 and the current detection circuit 254 and the current cutoff circuit 255 shown in FIG. 6, power supply terminal pieces 271 and 272, and a motor connection terminal. It includes pieces 261, 262, 263, and a lead terminal 257. The power supply terminal pieces 271 and 272 are erected with respect to the first mounting surface 25AF of the first power board 25A. The motor connection terminal pieces 261, 262, and 263 are erected with respect to the first mounting surface 25AF of the first power board 25A.

As shown in FIG. 8C, the second power board 25B includes an electronic component 256 constituting the inverter circuit 251 and the current detection circuit 254 and the current cutoff circuit 255 shown in FIG. 6, power supply terminal pieces 271 and 272, and a motor connection terminal. It includes pieces 261, 262, 263, and a lead terminal 257. The power supply terminal pieces 271 and 272 are erected with respect to the second mounting surface 25BF of the second power board 25B. The motor connection terminal pieces 261, 262, and 263 are erected with respect to the second mounting surface 25BF of the second power board 25B.

The power supply terminal pieces 271 and 272 are plate materials having a good conductor such as copper or aluminum. The motor connection terminal pieces 261, 262, and 263 are plate materials having a good conductor such as copper or aluminum. As shown in FIGS. 8B and 8C, the surface of the plate material of the power supply terminal pieces 271 and 272 faces a different direction from the surface of the plate material of the motor connection terminal pieces 261, 262, and 263. It is desirable that the direction perpendicular to the surface of the plate material of the power supply terminal pieces 271 and 272 faces the direction of the axial direction Ax, and the direction perpendicular to the surface of the plate material of the motor connection terminal pieces 261, 262 and 263 is the axial direction Ax. It is desirable to face one radial tangent in a virtual plane perpendicular to the direction.

As shown in FIG. 8E, the sensor substrate 21 includes a rotation angle sensor 23a. The sensor board 21 is provided with a lead terminal 257 on the back surface of the mounting surface of the rotation angle sensor 23a.

As shown in FIG. 7, the connector CNT has power supply terminals Tdc and Tgnd. The power supply terminal Tdc is a metal terminal that supplies the power supply voltage Vdc of the power supply device 83. The power supply terminal Tgnd is a metal terminal that supplies a negative power supply voltage (for example, a reference voltage such as ground) of the power supply device 83.

The power supply terminal Tdc is pressed against the power supply terminal piece 272 (see FIG. 8B) of the first power substrate 25A, and is resistance welded or laser welded. As a result, one surface of the power supply terminal Tdc and one surface of the power supply terminal piece 272 of the first power board 25A are in surface contact with each other.

The power supply terminal Tgnd is pressed against the power supply terminal piece 271 (see FIG. 8B) of the first power substrate 25A, and is resistance welded or laser welded. As a result, one surface of the power supply terminal Tgnd and one surface of the power supply terminal piece 271 of the first power board 25A are in surface contact with each other.

The power supply terminals Tdc and Tgnd are also on the second power board 25B side of the connector CNT. The power supply terminal Tdc on the second power board 25B side is pressed against the power supply terminal piece 272 (see FIG. 8C) of the second power board 25B, and is resistance welded or laser welded. The power supply terminal Tgnd on the second power board 25B side is pressed against the power supply terminal piece 271 (see FIG. 8C) of the second power board 25B, and is resistance welded or laser welded.

FIG. 10A is a front view of the heat sink of this embodiment. FIG. 10B is a left side view of the heat sink of this embodiment. FIG. 10C is a right side view of the heat sink of this embodiment. FIG. 10D is a plan view of the heat sink of this embodiment. FIG. 10E is a bottom view of the heat sink of this embodiment. FIG. 10F is a rear view of the heat sink of this embodiment.

As shown in FIGS. 9 and 10A to 10F, the heat sink 40 connects the first heat radiating arm portion 41, the second heat radiating arm portion 42, the first heat radiating arm portion 41, and the second heat radiating arm portion 42. It is U-shaped with a connecting portion 43. As shown in FIG. 10A, the first heat radiating arm portion 41 and the second heat radiating arm portion 42 are arranged at a distance from each other by the connecting portion 43. Therefore, an opening 44 is formed between the first heat radiating arm portion 41 and the second heat radiating arm portion 42.

As shown in FIG. 8F, the connector CNT includes a choke coil 49. The choke coil 49 removes the high frequency component of the power wiring PW from the power supply device 83 described above. The choke coil 49 is arranged in the space of the opening 44. There is a connecting portion 43 between the choke coil 49 and the rotation angle sensor 23a (see FIG. 8E). The connecting portion 43 can shield the noise of the choke coil 49 so that the connecting portion 43 does not transmit the noise of the choke coil 49 to the rotation angle sensor 23a.

As shown in FIGS. 10A and 10B, the first heat radiation arm portion 41 has a first surface 41a arranged radially outside of the axial direction Ax shown in FIG. 7 and a radial inside of the axial direction Ax shown in FIG. The third surface 41c, the fourth surface 41d, and the fifth surface 41f, which are the side surfaces connecting the second surface 41b facing the opening 44 and the first surface 41a and the second surface 41b, and the fifth surface 41f. A sixth surface 41e opposite to the fifth surface 41f is provided.

As shown in FIG. 9, the back surface 25AR of the first mounting surface 25AF of the first power substrate 25A is fixed to the first heat dissipation arm portion 41 of the heat sink 40 with screws or the like. As a result, the back surface 25AR of the first mounting surface 25AF of the first power substrate 25A is in contact with the first surface 41a of the first heat radiating arm portion 41 shown in FIG. 10B directly or via a heat radiating material. The heat radiating material is a material obtained by mixing a heat conductive filler with a silicone polymer, and is called a TIM (Thermal Interface Material).

As shown in FIG. 10B, the first surface 41a has a recess 41H (see FIG. 9). When the back surface 25AR of the first mounting surface 25AF of the first power board 25A is attached to the first heat dissipation arm portion 41, the smoothing capacitor 253 is attached to face the bottom of the recess 41H as shown in FIG. 8G. As a result, even if the explosion-proof valve of the smoothing capacitor 253 is released, the electrolytic solution is unlikely to scatter.

A heat radiating material 48 is applied between the smoothing capacitor 253 and the bottom of the recess 41H. Since the heat radiating material 48 having a higher thermal conductivity than air is in contact with the end face of the smoothing capacitor 253 and the bottom of the recess 41H, the heat radiating efficiency is improved as compared with the case where the heat radiating material 48 is not present. The heat radiating material 48 does not necessarily have to be in contact with the entire surface of the bottom end surface of the recess 41H of the smoothing capacitor 253. The heat radiating material 48 may be in contact with at least a part of the bottom end surface of the recess 41H of the smoothing capacitor 253. However, it is preferable that the heat radiating material 48 is in contact with at least the center of the bottom end surface of the recess 41H of the smoothing capacitor 253. Further, the heat radiating material 48 may be in contact with not only the bottom end surface of the recess 41H of the smoothing capacitor 253 but also the outer peripheral surface of the smoothing capacitor 253.

As shown in FIGS. 10A and 10C, the second heat radiation arm portion 42 has a first surface 42a arranged radially outside of the axial direction Ax shown in FIG. 7 and a radial inside of the axial direction Ax shown in FIG. The third surface 42c, the fourth surface 42d, and the fifth surface 42f, which are the side surfaces connecting the second surface 42b facing the opening 44 and the first surface 42a and the second surface 42b, and the fifth surface. A sixth surface 42e opposite to the fifth surface 42f is provided.

As shown in FIG. 9, the back surface 25BR of the second mounting surface 25BF of the second power board 25B is fixed to the second heat dissipation arm portion 42 of the heat sink 40 with screws or the like. As a result, the back surface 25BR of the second mounting surface 25BF of the second power substrate 25B is in contact with the first surface 42a of the second heat radiating arm portion 42 shown in FIG. 10C directly or via the heat radiating material described above.

As shown in FIG. 10C, the first surface 42a has a recess 42H. When the back surface 25BR of the second mounting surface 25BF of the second power board 25B is attached to the second heat dissipation arm portion 42, the smoothing capacitor 253 is attached to face the bottom of the recess 42H as shown in FIG. 8G. As a result, even if the explosion-proof valve of the smoothing capacitor 253 is released, the electrolytic solution is unlikely to scatter.

A heat radiating material 48 is applied between the smoothing capacitor 253 and the bottom of the recess 42H. Since the heat radiating material 48 having a higher thermal conductivity than air is in contact with the end face of the smoothing capacitor 253 and the bottom of the recess 42H, the heat radiating efficiency is improved as compared with the case where the heat radiating material 48 is not present. The heat radiating material 48 does not necessarily have to be in contact with the entire surface of the bottom end surface of the recess 42H of the smoothing capacitor 253. The heat radiating material 48 may be in contact with at least a part of the bottom end surface of the recess 42H of the smoothing capacitor 253. However, it is preferable that the heat radiating material 48 is in contact with at least the center of the bottom end surface of the recess 42H of the smoothing capacitor 253. Further, the heat radiating material 48 may be in contact with not only the bottom end surface of the recess 42H of the smoothing capacitor 253 but also the outer peripheral surface of the smoothing capacitor 253.

As shown in FIG. 9, the control board 24 is fixed to the front surface of the heat sink 40 with screws or the like so as to straddle the first heat dissipation arm portion 41 and the second heat dissipation arm portion 42. As a result, the control board 24 is fixed to the surface intersecting the surface to which the first power board 25A and the second power board 25B are fixed. As described above, the third mounting surface of the control board 24 is different from the plane on which the first mounting surface 25AF of the mounting surface of the first power board 25A and the second mounting surface 25BF of the second power board 25B are arranged. As a result, the volume of the ECU 10 can be reduced. Further, since the first power board 25A and the second power board 25B are separated, the heat of the first power board 25A and the heat of the second power board 25B are not easily transferred to each other, and the heat concentration is suppressed. To.

As shown in FIGS. 9 and 10A, the third surface 41c of the first heat radiating arm portion 41 and the third surface 42c of the second heat radiating arm portion 42 are provided with a step and have a recess. As a result, in FIG. 10A, the control board 24 has a space of an opening 44 in a part of the third surface 41c of the first heat radiating arm portion 41 and a part of the third surface 42c of the second heat radiating arm portion 42. It is fixed so as to intervene. Further, since the heat sink 40 is U-shaped, the back surface of the control board 24 is exposed to the opening 44 of the heat sink 40. As a result, it becomes difficult for the heat of the first heat radiating arm portion 41 and the second heat radiating arm portion 42 to be transferred to the control board 24.

The connector CNT is fixed to the heat sink 40 so as to straddle the first heat radiating arm portion 41 and the second heat radiating arm portion 42. The connector CNTs are fixed to the fifth surface 41f of the first heat radiating arm portion 41 and the fifth surface 42f of the second heat radiating arm portion 42. Since the heat sink 40 has a U shape, the connector CNT faces the connecting portion 43.

As shown in FIG. 10E, the heat sink 40 includes a support portion 46 and a support portion 47. The support portion 46 is provided with a fastening hole 43H1 that penetrates in the axial direction Ax. The support portion 47 is provided with a fastening hole 43H2 that penetrates in the axial direction Ax. Explaining with reference to FIGS. 7 and 10E, the fastening hole 43H1 and the fastening hole 314 on the opposite load side of the electric motor 30 overlap each other, and the bolt is inserted to fasten the heat sink 40 and the electric motor 30. To. The fastening hole 43H2 and the fastening hole 315 on the opposite load side of the electric motor 30 overlap each other, and the bolt is inserted to fasten the heat sink 40 and the electric motor 30.

As shown in FIGS. 10B, 10C and 10F, the positions of the fourth surface 41d of the first heat radiating arm portion 41 and the fourth surface 42d of the second heat radiating arm portion 42 extend in the axial direction Ax and are counterbored. A recessed portion 421 (see FIG. 10D) is provided. As shown in FIG. 10D, the fastening hole 43H1 is exposed when viewed through the recess 421. This allows the driver to be inserted into the recess 421. As a result, the bolt to be inserted into the fastening hole 43H1 is arranged in the recess 421. Even if the volume of the cover 210 is maximized to improve the heat dissipation efficiency, it can be fixed to the electric motor 30.

As shown in FIG. 10E, the connecting portion 43 includes a recess 43H on the mounting surface of the sensor substrate 21. The connecting portion 43 includes a sensor substrate supporting portion 45 around the recess 43H. As shown in FIG. 8E, the sensor substrate 21 is fixed to the sensor substrate support portion 45 (see FIG. 10E) with screws or the like. The sensor substrate 21 is housed in the recess 43H of the heat sink 40 and is surrounded by the connecting portion 43. The sensor substrate 21 is fixed by the recess 43H so that a space is interposed between the sensor substrate 21 and the connecting portion 43. As a result, it becomes difficult for the heat of the first heat radiating arm portion 41 and the second heat radiating arm portion 42 to be transferred to the sensor substrate 21.

FIG. 11 is an explanatory diagram for explaining the positional relationship between the shaft, the magnet, and the rotation angle sensor of the present embodiment. As shown in FIGS. 11 and 7, the magnet 32 is fixed to the counterload side end of the shaft 31. The magnet 32 has S poles and N poles alternately arranged in the circumferential direction on the outer peripheral surface.

The sensor substrate 21 is on the opposite side of the shaft 31 and is arranged on an extension line in the axial direction Ax. The sensor substrate 21 has a plane orthogonal to the axial direction Ax as a mounting surface for the rotation angle sensor 23a. The rotation angle sensor 23a is mounted on the sensor substrate 21 so that it can detect a change 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 is, for example, a spin valve sensor. The spin valve sensor is an element in which a non-magnetic layer is sandwiched between a ferromagnetic pin layer whose magnetization direction is fixed by an antiferromagnetic layer or the like and a ferromagnetic free layer, and detects a change in the magnetic flux direction. It is a sensor that can be used. Spin valve sensors include GMR (Giant Magneto Resistance) sensors and TMR (Tunnel Magneto Resistance) sensors. The rotation angle sensor 23a may be any sensor that can detect the rotation of the magnet 32. The rotation angle sensor 23a may be, for example, an AMR (Anisotropic Magneto Resistance) sensor or a Hall sensor.

FIG. 12 is an explanatory diagram for explaining the connection between the motor connection terminal and the coil wiring of the present embodiment. As shown in FIG. 7, the electric motor 30 has coil wirings 321, 322, and 323 protruding to the opposite load side. The coil wirings 321, 322, and 323 are copper wires or aluminum wires, which are so-called plate-shaped flat wires. The planes of the motor connection terminal pieces 261, 262, and 263 face the planes of the coil wirings 321, 322, and 323, and are pressed against each other so that the planes are in contact with each other, and are subjected to resistance welding or laser welding.

FIG. 13 is an explanatory diagram for explaining the connection between the first power board and the control board of the present embodiment. As shown in FIG. 13, in the electrical connection portion Q between the control board 24 and the first power board 25A, the lead terminal 257 is inserted into the lead insertion hole 248 and joined with a metal paste such as solder. The connection portion Q can be connected to the conductor on the inner wall surface of the lead insertion hole 248 by bending the outer circumference of the lead terminal 257 so that it can be elastically deformed, even if it is a solderless electrical connection, so-called press fit. Good. The electrical connection portion between the control board 24 and the second power board 25B has the same structure as the connection portion Q described above (hereinafter referred to as the connection portion Q). Further, the electrical connection portion between the control board 24 and the sensor board 21 has the same structure as the connection portion Q described above (hereinafter referred to as the connection portion Q).

As shown in FIG. 7, the power supply voltage of the power supply device 83 is supplied to the first power board 25A and the second power board 25B via the power supply terminals Tdc and Tgnd. As shown in FIG. 6, the power supply voltage of the power supply device 83 supplied to at least one of the first power board 25A and the second power board 25B is supplied to the control board 24 via the connection portion Q described above. There is. Similarly, the power supply voltage of the power supply device 83 supplied to the control board 24 is supplied to the sensor board 21 via the connection portion Q.

As described above, the electric drive device 1 shown in FIG. 3 is arranged in the vicinity of the first rack and pinion mechanism 99 and the second rack and pinion mechanism 70. Therefore, the joint portion between the ECU 10 and the electric motor 30 is sealed via a sealing member so that moisture and dust do not enter the inside of the ECU 10 and the electric motor 30 as much as possible. Further, the connector CNT and the cover main body 211 also have a sealed structure in order to improve waterproofness and dustproofness.

FIG. 14 is an explanatory diagram for explaining the fixing of the connector of the present embodiment. FIG. 15 is an explanatory diagram for explaining a sealed structure of the connector of the present embodiment. As shown in FIGS. 7 and 14, the cover 210 has a through hole 212 for exposing the connector CNT on the front surface of the cylindrical cover main body 211. As shown in FIG. 15, the inner wall 219 of the through hole 212 is provided with a protrusion 221 projecting inside the cover 210 (on the side of the electric motor 30 in the axial direction Ax). The outer diameter side of the connector CNT is provided with an overhang bottom portion 233 and a weir portion 232 in which the radial outside of the overhang bottom portion 233 is bent to the outside of the cover 210 (the side opposite to the electric motor 30 in the axial direction Ax). A concave storage portion 231 is formed between the overhanging bottom portion 233, the weir portion 232, and the connector CNT main body, and the end portion of the protrusion 221 is inserted into the storage portion 231.

When the storage portion 231 is filled with the sealing material, the space between the storage portion 231 and the protrusion 221 is sealed, and a sealed structure is completed between the cover main body 211 and the connector CNT. The sealing material may be an O-ring of an elastic member such as a gasket, an adhesive, or rubber.

As shown in FIG. 7, the cover 210 has a fastening hole 213 provided in the attachment portion of the cover main body 211. The electric motor 30 includes a fastening hole 313 for fixing the cover 210. The cover 210 and the electric motor 30 are fixed by bolts inserted into the fastening holes 213 and the fastening holes 313. The outer diameter of the cover body 211 is substantially the same as the outer diameter of the electric motor 30. As a result, the electric drive device 1 can be mounted in a state where interference with other outer parts is suppressed (see FIG. 3). Since the fastening holes 213 and the fastening holes 313 are equally divided at three locations in the circumferential direction, they are not easily loosened even if vibration or the like is applied when they are fixed with bolts.

As described above, the electric drive device 1 includes an electric motor 30 and an ECU 10 provided on the opposite load side of the shaft 31 in order to drive and control the electric motor 30. The ECU 10 includes a magnet 32 at the end of the shaft 31 on the opposite load side, a sensor board 21 on which the rotation angle sensor 23a is mounted, a first power board 25A, a second power board 25B, and a control board 24. Here, the rotation angle sensor 23a is a magnetic sensor that detects the rotation of the magnet 32.

The first power substrate 25A mounts a plurality of electronic components 256 that supply a current to the first coil group Gr1 on the first mounting surface 25AF that is radially outer of the shaft 31. The second power board 25B mounts a plurality of electronic components 256 that supply a current to the second coil group Gr2 on the second mounting surface 25BF that is radially outer of the shaft 31. The control board 24 mounts an electronic component 245 that controls a current supplied by at least one of the first power board 25A and the second power board 25B on a third mounting surface on the radial outer side of the shaft 31.

The first power board 25A, the second power board 25B, and the control board 24 are arranged around the extension line in the axial direction of the shaft 31. The first power board 25A, the second power board 25B, the control board 24, and the electric motor 30 are arranged so as to sandwich the sensor board 21.

According to this structure, since the sensor substrate 21 is arranged closer to the electric motor 30, the shaft 31 can be shortened. As a result, the swing of the shaft 31 is suppressed, and the vibration of the electric motor 30 is suppressed. Further, by suppressing the swing of the shaft 31, the accuracy of detecting the rotation angle of the rotation angle sensor 23a is improved.

In the electric drive device 1 of the present embodiment, the ECU 10 includes a magnet 32 at the end of the shaft 31 on the opposite load side and a substrate assembly 200. The board assembly 200 includes a heat sink 40, a sensor board 21, a first power board 25A, a second power board 25B, and a control board 24.

In the board assembly 200, the first power board 25A, the second power board 25B, and the control board 24 are arranged around the extension line of the axial direction Ax of the shaft 31 so that the first power board 25A, the second power board 25B, and the control board 24 are arranged. The 25B and the control board 24 are assembled to the heat sink 40. The first power board 25A, the second power board 25B, and the control board 24 are assembled with the sensor board 21 on the heat sink 40 so as to sandwich the sensor board 21 with the electric motor 30 in the axial direction Ax. Then, the substrate assembly 200 is fixed to the opposite load side of the electric motor 30.

According to this structure, by fixing the pre-assembled board assembly 200 to the counterload side of the electric motor 30, the first power board 25A, the second power board 25B, the control board 24, and the sensor board 21 become the electric motor. Attached to 30. Therefore, the efficiency of the mounting work is improved.

The first power board 25A and the second power board 25B are provided with power supply terminal pieces 271 and 272 standing near the connector CNT and standing near the sensor board 21 in the axial direction Ax of the shaft 31, respectively. There are motor connection terminal pieces 261 and 262, 263. By attaching the connector CNT to the board assembly 200, the power supply terminal pieces 271 and 272 are connected to the power wiring PW. By fixing the substrate assembly 200 to the opposite load side of the electric motor 30, the motor connection terminal pieces 261, 262, and 263 are easily connected to the coil wirings 321, 322, and 323.

The power supply terminal pieces 271, 272 and the motor connection terminal pieces 261, 262, 263 are good conductor plates, and one surface of the plate materials of the power supply terminal pieces 271, 272 can be visually recognized from the axial direction Ax, and the motor connection terminal pieces. One surface of the plate materials of 261 and 262, 263 is visible from the direction of the tangent line in the radial direction. With this structure, the power terminal pieces 271 and 272 can be easily connected to the power wiring PW by attaching the connector CNT to the axial direction Ax. Further, by abutting the substrate assembly 200 on the opposite load side of the electric motor 30 in the axial direction Ax and rotating the substrate assembly 200 slightly in the axial direction Ax, the motor connection terminal pieces 261, 262, and 263 are separated. The coil wirings 321, 322, and 323 can be easily contacted with each other. This improves the efficiency of the assembly work.

As shown in FIG. 7, on the counterload side of the electric motor 30, there is a positioning boss 330 that serves as a protrusion for positioning. The positioning boss 330 regulates the position of the substrate assembly 200.

As shown in FIGS. 8E and 10E, the connecting portion 43 of the heat sink 40 is provided with a recess 43H3 at a position corresponding to the positioning boss 330. The positioning boss 330 and the recess 43H3 are fitted to each other, and the position of the substrate assembly 200 with respect to the electric motor 30 is restricted.

As shown in FIG. 7, after fixing the substrate assembly 200 on the antiload side of the electric motor 30, the cover 210 covering the entire substrate assembly 200 is fixed on the antiload side of the electric motor 30. As a result, a part of the connector CNT penetrates through the through hole 212, and as described above, a hermetically sealed structure is easily completed between the cover main body 211 and the connector CNT.

As shown in FIG. 7, the electric drive device 1 includes an internal pressure adjusting unit 218 that enhances waterproofness and dustproofness while maintaining ventilation with a porous material. By the way, the internal pressure of the internal space surrounded by the cover main body 211 may change due to an external environment such as a temperature rise. Even in this case, since the internal space is ventilated to the outside via the internal pressure adjusting unit 218, the change in the internal pressure of the internal space surrounded by the cover main body 211 is suppressed with the passage of time. As a result, damage to the cover main body 211 and damage to the joint portion between the cover main body 211 and the electric motor 30 are suppressed, and the durability of the electric drive device 1 is improved.

As shown in FIG. 7, the coil wirings 321, 322, and 323 are arranged radially outside the heat sink 40. As a result, the coil wirings 321, 322, and 323 are arranged radially outside the sensor substrate 21, so that the heat sink 40 suppresses the influence of the magnetic fields of the coil wirings 321, 322, and 323.

The first power board 25A and the second power board 25B generate heat when the inverter circuit 251 operates. As shown in FIG. 7, the first power substrate 25A is arranged at a position sandwiching the extension line of the axial direction Ax of the shaft 31 from the second power substrate 25B. As a result, when both the first power board 25A and the second power board 25B are operating, the bias of the heat generation distribution is alleviated in the internal space of the cover 210. In this embodiment, the first power board 25A and the second power board 25B are parallel to each other. The first power substrate 25A and the second power substrate 25B may be arranged on a non-parallel plane with an extension line of the shaft 31 in the axial direction Ax.

The heat sink 40 includes a first heat radiating arm portion 41, a second heat radiating arm portion 42, and a connecting portion 43, and has a U shape. The back surface 25AR of the first mounting surface 25AF of the first power board 25A is attached to the first surface 41a on the radial outer side of the first heat dissipation arm portion 41, and the back surface 25BR of the second mounting surface 25BF of the second power board 25B is , It is attached to the first surface 42a on the radial outer side of the second heat dissipation arm portion 42. There is a space for the opening 44 between the second surface 41b on the inner side in the radial direction of the first heat radiating arm portion 41 and the second surface 42b on the inner side in the radial direction of the second heat radiating arm portion 42. According to this structure, even if the operating ratios of the first power board 25A and the second power board 25B are different, the heat transferred to the first heat dissipation arm portion 41 and the heat transferred to the second heat dissipation arm portion 42 are transmitted. The heat is separated by the space of the opening 44, and heat can be dissipated. That is, the heat interference between the heat transferred to the first heat radiating arm portion 41 and the heat transmitted to the second heat radiating arm portion 42 is suppressed. Further, the presence of the second surface 41b on the radial inside of the first heat dissipation arm portion 41 and the second surface 42b on the radial inside of the second heat dissipation arm portion 42 increases the heat dissipation area of the heat sink 40 and dissipates heat. Increased efficiency.

For example, in the second power board 25B, when the current value detected by the current detection circuit 254 is determined to be abnormal, the control calculation unit 241 drives the current cutoff circuit 255 via the cutoff drive circuit 243, and the inverter circuit 251 The current flowing from the second coil 38 to the second coil 38 is cut off. The control calculation unit 241 causes a current to flow to the first coil 37 only from the inverter circuit 251 of the first power board 25A. As a result, the heat generation of the first power substrate 25A increases, and the heat generation of the second power substrate 25B decreases. Even in this case, the heat transferred from the first power substrate 25A to the first heat radiating arm portion 41 is efficiently radiated. Even when the heat generation of the second power board 25B increases and the heat generation of the first power board 25A decreases, the heat transferred to the first heat dissipation arm portion 41 and the heat transferred to the second heat dissipation arm portion 42 are similarly transmitted. The heat is separated by the space of the opening 44, and heat can be dissipated.

The heat generated by the smoothing capacitor 253 is conducted to the heat sink 40 via the bottom end surface of the recess 41H or the recess 42H. The electronic control device (ECU 10) of the present embodiment can improve the heat dissipation efficiency of the smoothing capacitor 253. The temperature of the electronic components arranged around the smoothing capacitor 253 is also kept low, so that the life of these electronic components is extended. Further, since the temperature difference between the two smoothing capacitors 253 becomes small, the variation in the voltage of the three-phase AC supplied to the electric motor 30 is suppressed. As a result, the torque ripple of the electric motor 30 is suppressed.

Further, the electric power steering device 100 includes an electronic control device (ECU 10) and an electric motor 30 controlled by the electronic control device (ECU 10) to generate auxiliary steering torque. As a result, the efficiency of the assembly work of the electric power steering device 100 is improved.

1 Electric drive device 10 ECU (electronic control device)
21 Sensor board 22 Motor rotation speed calculation unit 23 Motor rotation angle detection circuit 23a Rotation angle sensor 24 Control board 25A First power board 25B Second power board 30 Electric motor 31 Shaft 32 Magnet 37 First coil 38 Second coil 40 Heat sink 41 1st heat dissipation arm 42 2nd heat dissipation arm 41H, 42H, 43H Recesses 43H1, 43H2 Fastening hole 43 Connecting part 44 Opening 45 Sensor board support part 46, 47 Support part 48 Heat dissipation material 49 Chalk coil 70 Second rack and pinion Mechanism 71A 2nd pinion shaft 71B 2nd pinion gear 71C 2nd rack 72 Tie rod 75A Warm shaft 75B Warm wheel 75 Speed reducer 82 Vehicle speed sensor 83 Power supply 84 Ignition switch 91 Steering wheel 92 Steering shaft 92C Torsion bar 92B Output shaft 92A Input shaft 94 Torque Sensor 96 Universal Joint 97A Upper Shaft 97 Intermediate Shaft 97B Lower Shaft 98 Universal Joint 99 1st Rack and Pinion Mechanism 99A 1st Pinion Shaft 99B 1st Pinion Gear 99C Rack Shaft 99D 1st Rack 100 Electric Power Steering Device 101 Vehicle 200 Board Assembly 210 Cover 211 Cover body 212 Through hole 213 Fastening hole 218 Internal pressure adjustment part 219 Inner wall 221 Protrusion part 231 Storage part 232 Dam part 233 Overhang bottom part 241 Control calculation part 242 Gate drive circuit 243 Blocking drive circuit 245 Electronic component 248 Lead insertion Hole 251 Inverter circuit 252 Switching element 253 Smoothing capacitor 254 Current detection circuit 255 Current cutoff circuit 256 Electronic components 257 Lead terminals 261, 262, 263 Motor connection terminal pieces 271 Power supply terminal pieces 272 Power supply terminal pieces 313 Fastening holes 314 Fastening holes 315 Fastening holes 321 322, 323 Coil wiring 421 Recess 930 Housing 931 Stator core 931b Teeth 931a Back yoke 932b Magnet 932 Rotor 932a Rotor yoke Ax Axial CNT connector Gr1 1st coil group Gr2 2nd coil group PW Power wiring Q Connection part SV Vehicle speed signal T Steering Torque signal Tdc power supply terminal Tgnd power supply terminal θm Motor electric angle

Claims (6)

A shaft, a motor rotor interlocking with the shaft, a motor stator having a stator core for rotating the motor rotor, and at least two systems of a first coil group and a second coil group for each three phases, and the stator core is divided into three. With multiple coil groups excited by phase alternating current, and with an electric motor, including
An electronic control device provided on the opposite load side of the shaft for driving and controlling the electric motor is provided.
Electronic control device
A magnet at the end of the shaft on the opposite load side and a substrate assembly are provided.
The board assembly is
With a heat sink
A sensor substrate on the counterload side of the shaft, which is arranged on an extension line in the axial direction of the shaft and mounts a magnetic sensor for detecting the rotation of the magnet.
A first power substrate on which a plurality of electronic components for supplying current to the first coil group are mounted at least on the radial outer side of the shaft, and
A second power board on which a plurality of electronic components that supply current to the second coil group are mounted at least on the radial outer side of the shaft, and
A control board for mounting an electronic component that controls a current supplied by at least one of the first power board and the second power board at least on the radial side of the shaft is provided.
The first power board, the second power board, and the control board are arranged so that the first power board, the second power board, and the control board are arranged around an extension line in the axial direction of the shaft. The sensor board is assembled to the heat sink, and the sensor board is assembled to the heat source so that the first power board, the second power board, the control board, and the electric motor sandwich the sensor board in the axial direction.
In the first power substrate, an electronic component mounted radially inside the shaft is inserted into a first recess provided in the heat sink.
In the second power substrate, an electronic component mounted radially inside the shaft is inserted into a second recess provided in the heat sink.
An electric drive device in which the substrate assembly is fixed to the opposite load side of the electric motor. A heat radiating material is interposed between the electronic component inserted into the first recess and the bottom of the first recess, and the electronic component inserted into the second recess and the bottom of the second recess The electric drive device according to claim 1, wherein a heat radiating material is interposed between the two. The first power board is arranged at a position sandwiching an extension line in the axial direction between the second power board and the shaft.
The heat sink includes a first heat radiating arm portion, a second heat radiating arm portion, and a connecting portion connecting the first heat radiating arm portion and the second heat radiating arm portion, and is U-shaped.
The first power board is attached to the radial outside of the first heat dissipation arm portion, and the second power board is attached to the radial outside of the second heat dissipation arm portion.
The first recess is provided on the radial outer side of the first heat dissipation arm portion.
The second recess is provided on the radial outer side of the second heat radiating arm portion.
The electric drive device according to claim 1 or 2, wherein there is a space between the radial inside of the first heat radiating arm portion and the radial inside of the second heat radiating arm portion. The electric drive device according to claim 3, wherein the control board is attached to the heat sink so as to straddle the first heat dissipation arm portion and the second heat dissipation arm portion. The electronic component mounted on the radial outside of the shaft of the first power board or the second power board includes a switching element and is mounted on the radial inside of the shaft of the first power board or the second power board. The electric drive device according to any one of claims 1 to 4, wherein the electronic component is a smoothing capacitor. The electric drive device according to any one of claims 1 to 5 is provided.
An electric power steering device in which the electric drive device generates auxiliary steering torque.

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