INTEGRAL-TYPE ELECTRIC POWER STEERING DEVICE

• US 20140239780A1
• Filed: 05/28/2012
• Published: 08/28/2014
• Est. Priority Date: 01/17/2012
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Tanaka, Daisuke, Asao, Yoshihito
• Granted Patent: US 10,017,203 B2
• Time in Patent Office: Days
• US Class Current: 310/68.D
• CPC Class Codes: B62D 5/0406 including housing for electronic control unit
• CPC Class Codes: B62D 5/0409 Electric motor acting on the steering column
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H02K 11/225 Detecting coils
• CPC Class Codes: H02K 11/33 Drive circuits, e.g. power electronics H02K11/38 takes precedence
• CPC Class Codes: H02K 7/1166 comprising worm and worm-wheel structural association with bearings specially adapted for worm gear drives H02K7/081
• CPC Class Codes: H05K 7/2039 characterised by the heat transfer by conduction from the heat generating element to a dissipating body arrangements for increasing/decreasing heat-transfer, e.g. fins details, F28F13/00

Abstract

An integral-type electric power steering device is configured in such a way that a motor component (40), a reduction mechanism (20), and a control device (50) are integrally fixed, and the control device (50) includes at least heating elements (531) having the control-circuit elements, which are operated so as to generate heat, a control board (53) on which the heating elements (531) are mounted, and a mechanism components (500) for fixing the control board (50); and at least a part of the heat, which is generated by the heating elements (531), is conducted to the mechanism components (500) via a thermal-conductive component (57).

Claims

1. An integral-type electric power steering device comprising:

a motor component including a motor that generates an assist torque corresponding to a steering torque caused by a driver in a car and applies the generated assist torque to a steering shaft of the car via a reduction mechanism; and

a control device including control-circuit elements for controlling the motor in a state where the motor component, the reduction mechanism, and the control device are integrally fixed;

wherein

the control device includes at least heating elements having the control-circuit elements, which are operated so as to generate heat, a control board on which the heating elements are mounted, and a mechanism components for fixing the control board; and

at least a part of the heat, which is generated by the heating elements, is conducted to the mechanism components via a thermal-conductive component.

2. An integral-type electric power steering device as recited in claim 1, wherein the control device is arranged between the reduction mechanism and the motor component, and the mechanism components include a reduction-mechanism-side case, which is connected to the reduction mechanism, and a motor-side case, which is connected to the motor component, and the control board is fixed to the reduction-mechanism-side case, and the heating elements are mounted on a surface of the control board, which faces to a wall surface of the motor-side case, and the thermal-conductive component is arranged between the heating elements and the wall surface of the motor-side case.

3. An integral-type electric power steering device as recited in claim 1, wherein the control device is arranged between the reduction mechanism and the motor component, and the mechanism components include a reduction-mechanism-side case, which is connected to the reduction mechanism, and a motor-side case, which is connected to the motor component, and the control board is fixed to the reduction-mechanism-side case, and the heating elements are mounted on a surface of the control board, which faces to a wall surface of the reduction-mechanism-side case, and the thermal-conductive component is arranged between the control board and the wall surface of the motor-side case, and is arranged at a position corresponding to the mounted heating elements.

4. An integral-type electric power steering device as recited in claim 3, wherein the motor-side case includes a convex portion, which is contacted to the thermal-conductive component, on the wall surface.

5. An integral-type electric power steering device as recited in claim 1, wherein the control device is arranged between the reduction mechanism and the motor component, and the mechanism components include a reduction-mechanism-side case, which is connected to the reduction mechanism, and a motor-side case, which is connected to the motor component, and the control board is fixed to the reduction-mechanism-side case, and the heating elements are mounted on a surface of the control board, which faces to a wall surface of the reduction-mechanism-side case, and the thermal-conductive component is arranged between the heating elements and the wall surface of the reduction-mechanism-side case.

6. An integral-type electric power steering device as recited in claim 5, wherein the reduction-mechanism-side case includes a convex portion, which is contacted to the thermal-conductive component, on the wall surface.

7. An integral-type electric power steering device as recited in claim 2, wherein the control-circuit elements include a power-circuit element, which control power supplied to the motor, and a power board on which at least the power-circuit element is mounted, and the power board is contacted to the reduction-mechanism-side case so as to be mounted.

8. An integral-type electric power steering device as recited in claim 1, wherein a control-device-integrated motor is configured in such a way that the motor component and the control device are integrally fixed to a rotor shaft of the motor in a direction where the rotor shaft of the motor is extended.

9. An integral-type electric power steering device as recited in claim 8, wherein the wall surface of the reduction-mechanism-side case and the wall surface of the motor-side case are arranged in a vertical direction with respect to the direction where the rotor shaft is extended.

10. An integral-type electric power steering device as recited in claim 1, wherein the motor component is arranged between the reduction mechanism and the control device, and

the mechanism components include a motor-side case, which is connected to the motor component, and a motor-opposite-side case, and the control board is fixed to the motor-side case, and the heating elements are mounted on a surface of the control board, which faces to a wall surface of the motor-side case, and the thermal-conductive component is arranged between the heating elements and the wall surface of the motor-side case.

11. An integral-type electric power steering device as recited in claim 10, wherein the motor-side case includes a convex portion, which is contacted to the thermal-conductive component, on the wall surface.

12. An integral-type electric power steering device as recited in claim 1, wherein the motor component is arranged between the reduction mechanism and the control device, and the mechanism components include a motor-side case, which is connected to the motor component, and a motor-opposite-side case, and the control board is fixed to the motor-side case, and the heating elements are mounted on a surface of the control board, which faces to a wall surface of the motor-opposite-side case, and the thermal-conductive component is arranged between the heating elements and the wall surface of the motor-opposite-side case.

13. An integral-type electric power steering device as recited in claim 12, wherein the motor-side case includes a convex portion, which is contacted to the thermal-conductive component, on the wall surface.

14. An integral-type electric power steering device as recited in claim 10, wherein the control-circuit elements include a power-circuit element, which control power supplied to the motor, and a power board on which at least the power-circuit element is mounted, and the power board is contacted to the motor-side case so as to be mounted.

15. An integral-type electric power steering device as recited in claim 10, wherein a control-device-integrated motor is configured in such a way that the motor component and the control device are integrally fixed to a rotor shaft of the motor in a direction where the rotor shaft is extended.

16. An integral-type electric power steering device as recited in claim 13, wherein the wall surface of the reduction-mechanism-side case and the wall surface of the motor-opposite-side case are arranged in a vertical direction with respect to the direction where the rotor shaft is extended.

17. An integral-type electric power steering device as recited in claim 4, wherein a contact-thermal-resister-reduction means is provided on a surface of the convex portion, which is contacted to the thermal-conductive component.

18. An integral-type electric power steering device as recited in claim 1, wherein the thermal-conductive component is formed in a sheet shape.

19. An integral-type electric power steering device as recited in claim 1, wherein the thermal-conductive component is made from a thermal-curable resin.

20. An integral-type electric power steering device as recited in claim 17, wherein the thermal-conductive component, which is made from a thermal-curable resin, is installed in the control device in a state where the resin is not stiffened, and then, the resin is stiffened.