Abstract: An electric motor 10 and a reduction gear mechanism 11 are connected to each other by a flexible coupling 12, such as an Oldham's coupling, which is a power transmission mechanism. Also, a casing 11c of the reduction gear mechanism 11 is integrally structured together with a knuckle 5, which is an unsprung part of a vehicle, or mounted to the knuckle 5. Further, a motor case 10a of the electric motor 10 is mounted to a motor mounting member 4m provided on the lower part of a strut 4 for suspending the knuckle 5 through the medium of a shock absorbing mechanism 20 equipped with a spring member 21, a damper, and two guide members 23 for guiding the operating direction of the spring member 21 and the damper. An in-wheel motor system thus structured allows the mass of the motor 10 to act as the mass of a dynamic damper and thus features not only improved ground contact performance and riding comfort of a vehicle running on a rough road but also superior space efficiency.

Abstract: An in-wheel motor system, wherein the non-rotating side case of a motor and the knuckle of a motor are connected to each other by a buffer mechanism 10 having plates 11 and 12 interconnected by a linear guide 15 with springs composed of a linear guide 13 consisting of a linear bearing 13A and a rod 13B and spring members 14 and 14 moving in the vertical direction of a vehicle and integrated with the linear guide 13 and a damper 16 moving in the vertical direction of the vehicle and interconnecting the plates 11 and 12. Thus, the motor can be securely float mounted to a part around the wheel of the vehicle and the buffer mechanism 10 can be easily assembled.