Patent ID: 8336652

Claim:
An in-wheel motor drive unit, comprising: a wheel hub bearing part, including: a wheel hub, fixed to a wheel of a car; an external member, connected to a car body and having an outer track surface facing an outer surface of the wheel hub; and a plurality of rolling elements, arranged between the wheel hub and the external member; a motor part, rotating and driving a motor-side rotation member which is arranged coaxially with respect to the wheel hub; and a deceleration part, decelerating the rotation of the motor-side rotation member and transmitting the decelerated rotation to the wheel hub, wherein, the motor-side rotation member has an eccentric part, the deceleration part includes: a revolution member, rotatably retained in the eccentric part and making a revolution motion in accordance with the rotation of the motor-side rotation member, around a rotation axis of the motor-side rotation member; an outer periphery engagement part, mechanically connected to the external member and engaging with an outer periphery of the revolution member to generate the rotation motion of the revolution member; a hole, provided on the revolution member; an inner pin, fixed to the wheel-side rotation member and received into the hole; and a wheel-side rotation member, connecting the inner pin with the wheel hub mechanically, wherein, the rotation motion of the revolution member is converted to the rotation motion of the inner pin engaging with the hole, around the rotation axis of the motor-side rotation member, and the rotation motion of the inner pin is transmitted to the wheel hub via the wheel-side rotation member.