US Patent 7701103 Electric motor

An electric motor (10) is an in-wheel motor. The motor (10) includes an outer rotor, (302), an inner rotor (301), a stator (200), and a shaft-shaped central portion (100). The outer rotor includes a magnet (305b) and is disposed closely to a load. The inner rotor includes a magnet (305a) and is disposed away from the load. The stator is disposed between the outer rotor and the inner rotor, and includes a stator coil. The shaft-shaped central portion extends completely through respective central portions of the outer rotor, the inner rotor and the stator. The shaft-shaped central portion defines a stationary structure. A power supply system (500) is provided using interiors of the stator (200) and the shaft shaped central portion (100).