JP2021136731A - Electrically-driven driver - Google Patents

Abstract

To provide an electrically-driven driver that can be downsized and can improve heat dissipation efficiency.SOLUTION: An electrically-driven driver comprises: a motor comprising a shaft that protrudes from a motor case and rotates; and a controller for controlling the motor. The controller comprises: a heat sink that comprises a partition wall having a hole penetrating in an axial direction of the shaft and is coupled to the motor case; a control board disposed on one side of the partition wall; and a power board disposed on the other side of the partition wall; and a connector. The connector comprises a plug disposed on one of the control board and the power board and a receptacle disposed on the other of the control board and the power board and penetrates the hole.SELECTED DRAWING: Figure 3

Description

The present invention relates to an electric drive device.

The electric power steering device that generates auxiliary steering torque by the motor includes a control device that is a device that controls the motor. For example, Patent Document 1 describes a drive device in which a control device and a motor are integrated.

Japanese Unexamined Patent Publication No. 2012-239295

By the way, since the electric drive device may be arranged in a narrow place, it is required to be small. On the other hand, in a drive device in which a control device and a motor are integrated, it is also required to improve heat dissipation efficiency. However, when the structure described in Patent Document 1 is adopted, there is a limit to miniaturization and improvement of heat dissipation efficiency.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an electric drive device that can be miniaturized and can improve heat dissipation efficiency.

In order to achieve the above object, the electric drive device of one aspect of the present disclosure includes a motor case, a motor including a shaft protruding from the motor case and rotating, and a control device for controlling the motor. The device is provided with a partition wall having a hole penetrating in the axial direction of the shaft, a heat sink connected to the motor case, a control board arranged on one side of the partition wall, and arranged on the other side of the partition wall. A power board, a plug arranged on one of the control board and the power board, and a connector provided on the control board and a receptacle placed on the other side of the power board and penetrating the hole.

As a result, the space occupied by the connecting members of the control board and the power board is reduced as compared with the case where the control board and the power board are connected outside the heat sink, for example. Therefore, the outer diameters of the motor case and the heat sink can be reduced. Further, the surface of the partition wall around the hole can be used as a heat radiating surface for contacting electronic components. Therefore, the heat dissipation efficiency is improved by bringing the electronic components mounted on the control board or the power board into contact with the partition wall. Therefore, the electric drive device of the present disclosure can be miniaturized and the heat dissipation efficiency can be improved.

As a preferred embodiment of the electric drive device, the connector is a floating connector.

This allows the plug and receptacle to be connected without generating excessive stress, even if there is a relative misalignment when mating to each other. The electric drive device of the present disclosure can easily assemble a control device.

As a desirable embodiment of the electric drive device, the power board is arranged so as to be in contact with both the power board main body, the switching element arranged on the partition wall side of the power board main body, and both the switching element and the partition wall. It is equipped with a heat radiating material.

As a result, heat dissipation of the switching element that generates the most heat among the electronic components provided on the power substrate is promoted. Therefore, the heat dissipation efficiency of the power board is improved as compared with the case where the heat radiating material is in contact with the power board main body. The electric drive device of the present disclosure can further improve heat dissipation efficiency.

As a preferred embodiment of the electric drive device, the control device includes a terminal that electrically connects the power board and the motor, and the terminal is arranged inside the motor case.

By arranging the terminal inside the motor case, the space between the control board and the power board is increased. Therefore, it is possible to increase the volume of the heat sink arranged between the control board and the power board. As a result, the electric drive device of the present disclosure can further promote heat dissipation of the control board and the power board.

According to the electric drive device of the present disclosure, it is possible to reduce the size and improve the heat dissipation efficiency.

FIG. 1 is a schematic view of the electric power steering device of the embodiment. FIG. 2 is a side view of the electric drive device of the embodiment. FIG. 3 is an exploded perspective view of the control device of the embodiment. FIG. 4 is a perspective view of the heat sink of the embodiment. FIG. 5 is a perspective view of the heat sink of the embodiment. FIG. 6 is a perspective view of the control board, the connector, and the cover of the embodiment. FIG. 7 is a perspective view of the power board, the connector, and the terminal of the 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). In addition, 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. Further, in the following embodiment, the same components as those described above may be designated by the same reference numerals, and duplicate description may be omitted as appropriate.

FIG. 1 is a schematic view of the electric power steering device of the embodiment. 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. A rack and pinion mechanism 99 and a tie rod 72 are provided. Further, the electric power steering device 100 includes a torque sensor 94 that detects the steering torque of the steering shaft 92, a motor 30, a control device (hereinafter, referred to as an ECU (Electronic Control Unit)) 10 that controls the motor 30, and deceleration. A 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. The vehicle speed sensor 82 outputs the detected vehicle speed signal to the ECU 10 by CAN (Control Area Network) communication. Electric power is supplied to the ECU 10 from the power supply device 83 with the ignition switch 84 turned on.

As shown in FIG. 1, 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 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.

FIG. 2 is a side view of the electric drive device of the embodiment. As shown in FIG. 2, the electric drive device 1 includes a motor 30 and an ECU 10.

The motor 30 is a motor that generates an auxiliary steering torque for assisting the driver's steering. The motor 30 may be a brushless motor or a brush motor having a brush and a commutator. As shown in FIG. 2, the motor 30 includes a motor case 35, a cover 38, and a shaft 31. The motor case 35 is made of a metal such as an aluminum alloy. The motor case 35 incorporates a stator around which a coil is wound, a rotor, and the like. The cover 38 is a member for closing the opening provided on the outer peripheral surface of the motor case 35. The shaft 31 projects from the motor case 35. The shaft 31 rotates together with the rotor. The motor 30 includes two coil groups. Different currents are supplied to the two coil groups.

The ECU 10 includes a rotation angle sensor 23a. The rotation angle sensor 23a detects the rotation phase of the motor 30. The ECU 10 acquires the rotation phase signal of the motor 30 from the rotation angle sensor 23a, acquires the steering torque signal from the torque sensor 94, and acquires the vehicle speed signal of the vehicle 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, and the vehicle speed signal. The ECU 10 supplies a current to the motor 30 based on the calculated auxiliary steering command value. An electrolytic capacitor is connected to the inverter circuit as a smoothing capacitor. The ECU 10 generates a three-phase alternating current by an inverter circuit including a plurality of switching elements. For example, the ECU 10 generates two systems of three-phase alternating current. The ECU 10 excites one coil group of the motor 30 by three-phase alternating current of one system. The ECU 10 excites the other coil group of the motor 30 by the three-phase alternating current of the other system. Even if the ECU 10 cannot supply the three-phase alternating current of one system to the motor 30, the ECU 10 can control the motor 30 by the three-phase alternating current of the other system. The ECU 10 is a so-called redundant control device.

The speed reducing device 75 includes a worm shaft 75A that rotates integrally with the shaft 31 of the 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.

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 motor 30 is transmitted to the second rack and pinion mechanism 70 via the speed reducing device 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 input to the steering shaft 92 from the torque sensor 94. The ECU 10 acquires the vehicle speed signal from the vehicle speed sensor 82. 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 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.

As shown in FIG. 1, 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. 3 is an exploded perspective view of the control device of the embodiment. FIG. 4 is a perspective view of the heat sink of the embodiment. FIG. 5 is a perspective view of the heat sink of the embodiment. FIG. 6 is a perspective view of the control board, the connector, and the cover of the embodiment. FIG. 7 is a perspective view of the power board, the connector, and the terminal of the embodiment.

As shown in FIG. 3, the ECU 10 includes a heat sink 11, a control board 13, a cover 17, a power board 15, a terminal 19, and a connector 40. The terminal 19, the power board 15, the heat sink 11, the control board 13, and the cover 17 are arranged in this order from the side closest to the motor 30.

The heat sink 11 supports the control board 13 and the power board 15. The heat sink 11 promotes heat dissipation from the control board 13 and the power board 15. The heat sink 11 is made of a metal such as an aluminum alloy. As shown in FIGS. 4 and 5, the heat sink 11 includes a partition wall 111 and a peripheral wall 113.

As shown in FIG. 3, the partition wall 111 is a member that separates the control board 13 and the power board 15. The partition wall 111 has a disk shape. The partition wall 111 includes a hole 112. The hole 112 penetrates in the axial direction of the shaft 31 of the motor 30. The hole 112 has a substantially rectangular shape. The holes 112 are arranged so as to overlap the straight line that divides the circle drawn by the partition wall 111 into two equal parts when viewed from the axial direction of the shaft 31. A part of the hole 112 overlaps the center of the disk-shaped partition wall 111 when viewed from the axial direction of the shaft 31. The peripheral wall 113 is a cylindrical member. The peripheral wall 113 extends in the axial direction of the shaft 31 from the outer edge of the partition wall 111. The peripheral wall 113 covers the control board 13. The peripheral wall 113 is fixed to the motor case 35. The peripheral wall 113 includes a plurality of flanges protruding in the radial direction. The flange of the peripheral wall 113 is connected to the flange provided on the motor case 35 by a fixing member such as a screw. The gap between the motor case 35 and the peripheral wall 113 is sealed with a sealing member such as an O-ring arranged on the outer peripheral surface of the peripheral wall 113, for example.

As shown in FIG. 6, the control board 13 includes a control board main body 131 and a plurality of electronic components. The control board main body 131 is a printed circuit board made of, for example, resin. The control board main body 131 is supported by the cover 17. The plurality of electronic components mounted on the control board main body 131 include, for example, a microcomputer having a central processing unit (CPU). The plurality of electronic components are arranged on both sides of the control board main body 131. The control board 13 calculates the current command value.

As shown in FIG. 3, the cover 17 is a member that closes the opening at one end of the heat sink 11. The cover 17 is made of a metal such as an aluminum alloy. As shown in FIG. 6, the control board 13 is attached to the surface of the cover 17 on the motor 30 side. A connector used for connection with a power source, CAN communication, and the like is attached to the surface of the cover 17 opposite to the motor 30. The gap between the connector and the cover 17 is sealed with a sealing member such as an O-ring. The cover 17 is fixed to the heat sink 11. The cover 17 includes a plurality of flanges protruding in the radial direction. The flange of the cover 17 is connected to the flange of the peripheral wall 113 of the heat sink 11 by a fixing member such as a screw. The gap between the cover 17 and the peripheral wall 113 is sealed with a sealing member such as an O-ring arranged on the outer peripheral surface of the cover 17, for example.

As shown in FIG. 7, the power substrate 15 includes a power substrate main body 151, a plurality of electronic components including a switching element 153 and an electrolytic capacitor 158, and a heat radiating material 155. The power board main body 151 is a printed circuit board made of, for example, resin. The plurality of electronic components are arranged on both sides of the power board main body 151. The power board main body 151 is connected to a power source. That is, the power board main body 151 is connected to the connector of the cover 17 connected to the power supply. The power board main body 151 is fixed to the heat sink 11. The power board main body 151 is connected to the partition wall 111 of the heat sink 11 by a fixing member such as a screw.

The switching element 153 is, for example, an electrolytic effect transistor (FET). The switching element 153 is arranged on the surface of the power substrate main body 151 opposite to the motor 30. That is, the switching element 153 is arranged on the partition wall 111 side of the power substrate main body 151. A three-phase alternating current is generated by an inverter circuit composed of a switching element 153. The switching element 153 is controlled based on the current command value calculated by the control board 13. The switching element 153 is the component that generates the most heat among the plurality of electronic components provided on both sides of the power board main body 151. The electrolytic capacitor 158 is arranged on the surface of the power board main body 151 on the motor 30 side. The electrolytic capacitor 158 is a smoothing capacitor for an inverter circuit. The heat radiating material 155 is arranged so as to be in contact with both the switching element 153 and the partition wall 111. The heat radiating material 155 promotes the transfer of heat of the switching element 153 to the heat sink 11. The heat radiating material 155 is a material obtained by mixing a heat conductive filler with a silicone polymer, and is called TIM (Thermal Interface Material).

The terminal 19 electrically connects the power board 15 and the motor 30. The terminal 19 is fixed to the power board main body 151. The terminal 19 is connected to the power board main body 151 by a fixing member such as a screw. The terminal 19 is arranged on the motor 30 side of the power board main body 151. The terminal 19 is arranged inside the motor case 35. The motor terminal of the motor 30 is connected to the terminal 19. The motor terminal is connected to the terminal 19 by a fixing member such as a screw. The two systems of three-phase alternating current generated by the power board 15 are supplied to the motor 30 via the two systems of motor terminals. The connection portion of the terminal 19 with the motor terminal is arranged so as to overlap the opening on the outer peripheral surface of the motor case 35. Therefore, it is possible to connect the motor terminal to the terminal 19 with the ECU 10 in the motor case 35. After connecting the motor terminals to the terminal 19, the opening of the motor case 35 is closed by the cover 38 shown in FIG. The gap between the motor case 35 and the cover 38 is sealed with a sealing member such as an O-ring arranged on the outer peripheral surface of the cover 38, for example. Further, for example, when a problem occurs in one of the motor 30 and the ECU 10, the motor 30 and the ECU 10 may be separated. In the electric drive device 1 of the present embodiment, the ECU 10 can be easily removed from the motor 30 by removing the cover 38.

The connector 40 electrically connects the control board 13 and the power board 15. The connector 40 transmits a signal between the control board 13 and the power board 15. The connector 40 is called a board-to-board (BtoB) connector. The connector 40 is, for example, a floating connector. The floating connector is a connector that has a movable part and can absorb the misalignment at the time of fitting. The connector 40 is arranged so as to penetrate the hole 112 of the partition wall 111. That is, at least a part of the connector 40 is arranged inside the hole 112. The connector 40 faces the inner wall of the hole 112. The connector 40 includes a plug 41 and a receptacle 45.

As shown in FIG. 7, the plug 41 is mounted on the power board main body 151. The plug 41 is arranged on the surface of the power board main body 151 opposite to the motor 30. That is, the plug 41 is arranged on the surface of the power board main body 151 on the partition wall 111 side. The plug 41 penetrates the hole 112 of the partition wall 111.

As shown in FIG. 6, the receptacle 45 is mounted on the control board 13. The receptacle 45 is arranged on the surface of the control board 13 on the motor 30 side. That is, the receptacle 45 is arranged on the surface of the control substrate 13 on the partition wall 111 side. The receptacle 45 fits into the plug 41. A signal is transmitted between the control board 13 and the power board 15 by contacting a plurality of contacts which are conductive members provided on the receptacle 45 and a plurality of contacts which are conductive members provided on the plug 41.

The connector 40 does not necessarily have to be a floating connector. The type of the connector 40 is not particularly limited as long as a signal can be transmitted between the control board 13 and the power board 15. The plug 41 may be mounted on the control board 13 instead of the power board main body 151. The receptacle 45 may be mounted on the power board main body 151 instead of the control board 13.

As described above, the electric drive device 1 of the present embodiment includes a motor case 35, a motor 30 including a shaft 31 protruding from the motor case 35 and rotating, and a control device (ECU 10) for controlling the motor 30. Be prepared. The control device includes a heat sink 11, a control board 13, a power board 15, and a connector 40. The heat sink 11 includes a partition wall 111 having a hole 112 penetrating in the axial direction of the shaft 31, and is connected to the motor case 35. The control board 13 is arranged on one side of the partition wall 111. The power substrate 15 is arranged on the other side of the partition wall 111. The connector 40 includes a plug 41 arranged on one side of the control board 13 and the power board 15, and a receptacle 45 arranged on the other side of the control board 13 and the power board 15, and penetrates the hole 112.

As a result, the space occupied by the connecting members of the control board 13 and the power board 15 is reduced as compared with the case where the control board 13 and the power board 15 are connected to the outside of the heat sink 11, for example. Therefore, the outer diameters of the motor case 35 and the heat sink 11 can be reduced. Further, the surface of the partition wall 111 around the hole 112 can be used as a heat radiating surface for contacting electronic components. Therefore, the heat dissipation efficiency is improved by bringing the electronic components mounted on the control board 13 or the power board 15 into contact with the partition wall 111. Therefore, the electric drive device 1 of the present embodiment can be miniaturized and the heat dissipation efficiency can be improved.

In the electric drive device 1 of the present embodiment, the connector 40 is a floating connector.

As a result, the plug 41 and the receptacle 45 can be connected without generating excessive stress even if there is a relative positional deviation when they are fitted to each other. The electric drive device 1 of the present embodiment can easily assemble the control device (ECU 10).

In the electric drive device 1 of the present embodiment, the power substrate 15 is in contact with both the power substrate main body 151, the switching element 153 arranged on the partition wall 111 side of the power substrate main body 151, and the switching element 153 and the partition wall 111. The heat radiating material 155 to be arranged is provided.

As a result, heat dissipation of the switching element 153, which generates the most heat among the electronic components provided on the power substrate 15, is promoted. Therefore, the heat dissipation efficiency of the power substrate 15 is improved as compared with the case where the heat radiating material 155 is in contact with the power substrate main body 151. The electric drive device 1 of the present embodiment can further improve the heat dissipation efficiency.

The control device (ECU 10) of the present embodiment includes a terminal 19 that electrically connects the power board 15 and the motor 30. The terminal 19 is arranged inside the motor case 35.

By arranging the terminal 19 inside the motor case 35, the space between the control board 13 and the power board 15 is widened. Therefore, it is possible to increase the volume of the heat sink 11 arranged between the control board 13 and the power board 15. As a result, the electric drive device 1 of the present embodiment can further promote heat dissipation of the control board 13 and the power board 15.

1 Electric drive 10 ECU
11 Heat sink 13 Control board 15 Power board 17 Cover 19 Terminal 23a Rotation angle sensor 30 Motor 31 Shaft 35 Motor case 38 Cover 40 Connector 41 Plug 45 Receptacle 70 2nd rack and pinion mechanism 71A 2nd pinion shaft 71B 2nd pinion gear 71C 2nd Rack 72 Tie rod 75 Speed reducer 75A Warm shaft 75B Warm wheel 82 Vehicle speed sensor 83 Power supply 84 Ignition switch 91 Steering wheel 92 Steering shaft 92A Input shaft 92B Output shaft 92C Torsion bar 94 Torque sensor 96 Universal joint 97 Intermediate shaft 97A Upper 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 111 Partition 112 Hole 113 Peripheral wall 131 Control board body 151 Power board body 153 Switching element 155 Heat dissipation material 158 Electrolytic capacitor

Claims (4)

A motor case and a motor including a shaft that protrudes from the motor case and rotates.
A control device that controls the motor and
With
The control device is
A heat sink provided with a partition wall having a hole penetrating in the axial direction of the shaft and connected to the motor case.
A control board arranged on one side of the partition wall and
A power board arranged on the other side of the partition wall and
A connector having a plug arranged on one of the control board and the power board, and a receptacle arranged on the other side of the control board and the power board, and penetrating the hole.
An electric drive device equipped with. The electric drive device according to claim 1, wherein the connector is a floating connector. The power board is
Power board body and
A switching element arranged on the partition side of the power board main body and
A heat radiating material arranged so as to be in contact with both the switching element and the partition wall,
The electric drive device according to claim 1 or 2. The control device includes a terminal that electrically connects the power board and the motor.
The electric drive device according to any one of claims 1 to 3, wherein the terminal is arranged inside the motor case.

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