Abstract: An electric motor includes a stator and a rotor. The stator includes a stationary shell, a polymer element located in the stationary shell, a coil unit located in the polymer element, two covers each connected to a related one of two opposite sides of the stationary shell, two caps each attached to a related one of the covers, and two bearings each fit in a related one of the caps. The rotor includes an axle inserted through the coil unit and supported on the bearings, two shields each connected to a related one of two opposite sides of the axle, and two groups of magnets. Each of the groups of magnets is connected to a related one of the shields.

Abstract: The present invention is a gear system with a sun gear and planet gears used as a reduction gear, a gear speeder or a hub motor with a simple structure, a high reliability, a small size, a good speed ratio, a great efficiency and an output of a big torque.

Abstract: The present invention provides a coreless brush motor of simple structure with high usage efficiency, no copper loss and small mechanical loss.

Abstract: The present invention provides a brushless motor with a sensor unit, which is coreless-assembled and is of simple structure with high usage efficiency, no iron loss and small mechanical loss.