In-wheel motor drive device

An in-wheel motor drive device, comprising:

• a motor;
• a wheel bearing comprising a fixed ring, a rotation ring, and a plurality of rolling elements arranged between the fixed ring and the rotation ring;
• and
• a speed reducer configured to connect the motor and the wheel bearing to each other, the speed reducer being formed of a parallel shaft gear speed reducer comprising:
• a speed reducer input shaft, which is configured to rotate integrally with a rotation shaft of the motor, and comprises an input gear;
• a speed reducer output shaft, which is configured to rotate integrally with the rotation ring of the wheel bearing, and comprises an output gear;
• and
• an intermediate shaft comprising:
• a small-diameter intermediate gear configured to mesh with the output gear;
• and
• a large-diameter intermediate gear provided coaxially with the small-diameter intermediate gear,
• wherein a speed reduction ratio of the speed reducer is constant,
• wherein the large-diameter intermediate gear has a circumscribed circle which is superimposed with a pitch circle of the plurality of rolling elements of the wheel bearing when viewed from an axial direction, and
• wherein the speed reducer input shaft, the intermediate shaft, and the speed reducer output shaft are arranged to form a triangular shape when viewed from the axial direction.