MOTOR-DRIVEN POWER STEERING DEVICE

摘要

Provided is an electric power steering system that is not complicated in structure but is capable of reducing the occurrence of rattling noises. A controller applies slight rotational torque to a drive gear (5a) of a reduction mechanism also in a predetermined range in which a motor does not produce any steering operation assist force. That is, the motor is caused to produce slight rotational torque not enough to drive a driven gear (5b), and the rotational torque direction is reversed under a given condition. Accordingly, a backlash (BL) between the drive gear (5a) and the driven gear (5b) is eliminated.