Control device for electrically operated power steering system

• US 7,989,997 B2
• Filed: 05/28/2009
• Issued: 08/02/2011
• Est. Priority Date: 09/02/2008
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Hashimoto, Manabu, Kanazawa, Takuro, Mishima, Akira, Ochi, Kentaro
• Primary Examiner(s): Lam; Thanh
• Application Number:
  US12/473,662
• Publication Number:
  US 20100052449A1
• Time in Patent Office: 796 Days
• Field of Search: 310/68.R, 310/68.D, 310/71
• US Class Current: 310/68.00D
• CPC Class Codes: B62D 5/0406 including housing for electronic control unit

Abstract

A control device for an electrically operated power steering system includes: a power substrate comprising a plurality of switching elements, that converts DC electrical current to AC electrical current by switching operation of the plurality of switching elements; an output terminal for transmitting the AC electrical current to an electric motor that generates steering torque; a conductor for electrically connecting the power substrate to the output terminal; a metallic chassis that holds the power substrate and the conductor, and supports the output terminal; and a metallic cover that faces the output terminal, and that is connected to the metallic chassis.

Claims

1. A control device for an electrically operated power steering system, comprising:

a power substrate comprising a plurality of switching elements, that converts DC electrical current to AC electrical current by switching operation of the plurality of switching elements;

an output terminal for transmitting the AC electrical current to an electric motor that generates steering torque;

a conductor for electrically connecting the power substrate to the output terminal;

a metallic chassis that holds the power substrate and the conductor, and supports the output terminal; and

a metallic cover that faces the output terminal, and that is connected to the metallic chassis.

2. A control device for an electrically operated power steering system according to claim 1, wherein:

the output terminal is connected by a screw to a terminal of the electric motor; and

the metallic cover is supported so as to face the output terminal and the screw.

3. A control device for an electrically operated power steering system according to claim 1, wherein:

the metallic chassis comprises a metallic support portion, for integrally supporting an electric motor side metallic chassis that houses the electric motor; and

the metallic support portion is formed at a side portion of a connection portion between the metallic cover and the metallic chassis.

4. A control device for an electrically operated power steering system according to claim 1, further comprising:

a heat dissipation member that is provided upon a one surface of the power substrate opposite from another surface of the power substrate upon which the switching elements are provided, wherein

the heat dissipation member is provided with heat dissipation fins on an opposite side to a side that contacts the power substrate.

5. A control device for an electrically operated power steering system according to claim 1, further comprising:

a DC current system conductor unit to which DC electrical current is supplied from a power supply, and that supplies the DC electrical current to the switching elements, wherein

the DC current system conductor unit is provided at a side portion of the power substrate.

6. A control device for an electrically operated power steering system according to claim 5, wherein

the DC current system conductor unit is provided at a side portion of the power substrate and on the heat dissipation member.

7. A control device for an electrically operated power steering system according to claim 5, wherein

the DC current system conductor unit is provided at a side opposite from the metallic support portion, with the power substrate placing between the DC current system conductor unit and the metallic support portion.

8. A control device for an electrically operated power steering system according to claim 6, wherein

the DC current system conductor unit comprises a first connector for connecting to a battery power supply on a one surface of the DC current system conductor unit opposite from another surface of the DC current system conductor unit that contacts the heat dissipation member.

9. A control device for an electrically operated power steering system according to claim 8, wherein

the first connector of the DC current system conductor unit is provided more to an exterior than an end portion of the electric motor in its axial direction.

10. A control device for an electrically operated power steering system according to claim 1, further comprising:

a control board that transmits control signals to the switching elements and controls switching of the switching elements, wherein

the control board is provided so as to be positioned between the power substrate and the electric motor supported thereat, and is provided so that at least one portion thereof overlaps the DC current system conductor unit.

11. A control device for an electrically operated power steering system according to claim 10, wherein

the control board comprises, on a surface towards the electric motor, a second connector that inputs and outputs signals from and to the exterior of the control device for an electrically operated power steering system.

12. A control device for an electrically operated power steering system according to claim 11, wherein

the second connector of the control board is provided more towards the exterior than an end portion of the electric motor in its axial direction.

13. A control device for an electrically operated power steering system according to claim 5, wherein:

the DC current system conductor unit comprises an electrolytic capacitor for smoothing DC electrical current from the power supply, and a plate shaped conductor that is connected to the electrolytic capacitor; and

a plate shaped conductor through which electrical current on a positive electrode side of the electrolytic capacitor flows, and a plate shaped conductor through which electrical current on a negative electrode side of the electrolytic capacitor flows, are provided so as to be overlapped over one another.

14. A control device for an electrically operated power steering system according to claim 13, wherein:

when the electrolytic capacitor and the plate shaped conductor are connected together, a terminal of the electrolytic capacitor and a projecting portion of the plate shaped conductor are connected together; and

the terminal of the electrolytic capacitor and the projecting portion of the plate shaped conductor are provided so as to be overlapped over one another, and are connected so that directions of electrical currents that flow therein are mutually opposite.

15. A control device for an electrically operated power steering system according to claim 5, wherein:

the DC current system conductor unit further comprises an electrolytic capacitor for smoothing the DC electrical current from the power supply;

the electrolytic capacitor is formed in a cylindrical shape; and

a central cylindrical axis of the electrolytic capacitor and an axial direction of the electric motor agree with one another, and the electrolytic capacitor is provided so that a cylindrical end portion thereof upon which positive and negative terminals are provided is positioned towards the power substrate.