Electric power steering system

• US 20020148675A1
• Filed: 04/11/2002
• Published: 10/17/2002
• Est. Priority Date: 04/16/2001
• Status: Active Grant

• Current Assignee: Koyo Seiko Co., Ltd. (Toyota Motor Corporation)
• Original Assignee: Koyo Seiko Co., Ltd. (Toyota Motor Corporation)
• Inventors: Higashira, Hideki, Nakano, Yoshiaki
• Granted Patent: US 6,889,794 B2
• Time in Patent Office: Days
• US Class Current: 180/446
• CPC Class Codes: B60G 2400/42 Steering torque
• CPC Class Codes: B60G 2800/702 Improving accuracy of a sensor signal
• CPC Class Codes: B62D 15/0215 by measuring on the steering column
• CPC Class Codes: B62D 5/0406 including housing for electronic control unit
• CPC Class Codes: B62D 5/0463 calculating assisting torque from the motor based on driver input
• CPC Class Codes: B62D 5/0481 monitoring the steering system, e.g. failures
• CPC Class Codes: B62D 6/003 in order to control vehicle yaw movement, i.e. around a vertical axis B62D6/007 takes precedence
• CPC Class Codes: B62D 6/10 characterised by means for sensing or determining torque
• CPC Class Codes: G01L 3/101 involving magnetic or electromagnetic means
• CPC Class Codes: G01L 5/221 to steering wheels, e.g. for power assisted steering

Abstract

An electric power steering system according to the present invention comprises: a sensor module including a steering torque sensor and a control circuit housed therein; and a motor module including an electric motor and a motor driving circuit housed therein. The sensor module and the motor module are physically separately mounted in the electric power steering system. Since the sensor module and the motor module are physically separated, these modules can separately be produced, and the steering torque sensor and the electric motor can independently be adjusted.

Claims

1. An electric power steering system including a steering state detector for detecting a steering state of a motor vehicle, a control circuit which generates a control signal for controlling an electric motor on the basis of the steering state of the motor vehicle detected by the steering state detector, and a motor driving circuit which generates a signal for driving the electric motor on the basis of an output of the control circuit;

comprising;

a first module in which the steering state detector and the control circuit are housed; and

a second module in which the electric motor and the motor driving circuit are housed,

wherein the first module and the second module are separately mounted in the electric power steering system.

2. An electric power steering system as set forth in claim 1, wherein the steering state detector is a steering torque sensor for detecting a steering torque.

3. An electric power steering system as set forth in claim 2, wherein the steering torque sensor is a steering torque sensor of phase difference type.

4. An electric power steering system as set forth in claim 1, wherein the steering state detector is a steering angle sensor for detecting a steering angle.

5. An electric power steering system as set forth in claim 1, wherein the steering state detector is a yaw rate sensor for detecting a yaw rate of the motor vehicle.

6. An electric power steering system as set forth in claim 1, wherein the first module includes a central processing circuit, and the second module includes a central processing circuit.

7. An electric power steering system as set forth in claim 6, wherein the central processing circuit of the first module and the central processing circuit of the second module are mutually monitored by each other to check for malfunction thereof.

8. An electric power steering system as set forth in claim 1, wherein the first module has a function of correcting the steering state detector.

9. An electric power steering system as set forth in claim 1, wherein the second module has a function of correcting the electric motor.