To provide an electric power steering device can effectively prevent deterioration of operation sound generated by the vibration of a control unit, when the control unit is arranged in the vicinity of an electric motor and a gear box.
In this power steering device, steering assist force by the electric motor is imparted to a steering shaft. The power steering device includes the control unit for controlling driving of the electric motor based on steering torque generated in an input shaft of the steering shaft, a speed-reduction mechanism for transmitting rotation of the electric motor to an output shaft of the steering shaft, and a gear box for rotatably supporting the input shaft and output shaft and storing the speed-reduction mechanism. The control unit includes a box-shaped body of equipment having an opened surface and a circuit board mounted in the body of equipment, and the opened surface is fixed in a state brought into contact with a part of an outer surface of the gear box.
Sadayoshi Igarashi
Susumu Kitano