Patent ID: 7185732

Claim:
A motor-driven steering assist apparatus interposed between a steering wheel and a tire wheel side steering member and assisting a steering force applied to the steering wheel by a driver on the basis of a torque generated by an electric motor, comprising: an input shaft to which the steering wheel is connected; an output shaft to which the tire wheel side steering member is connected; a torque sensor which is provided between the input shaft and the output shaft; the electric motor being driven in correspondence to a detected torque of the torque sensor; a worm gear which is coupled to a rotating shaft of the electric motor; a worm wheel which is coupled to the output shaft, and which is engaged with the worm gear; the input shaft, the output shaft, the torque sensor, the electric motor, the worm gear and the worm wheel being installed within a single unit covered by first to third housings, an upper end portion of the input shaft and the torque sensor are supported by the first housing, an upper end portion of the output shaft, the electric motor, the worm gear and the worm wheel are supported by the second housing, a lower end portion of the output shaft is supported by the third housing, and the second housing is readily attached to the vehicle body side, wherein mounting bosses are provided at a plurality of positions in a peripheral direction of an outer periphery of the second housing, and the second is fastened to the vehicle body side by screwing the mounting bolt inserted and attached to the mounting boss to the vehicle body frame.