US Patent 7772731 Electric motor, rotary actuator and rotary apparatus

A rotary actuator including: a housing that rotatably supports thereinside a rotor shaft of an electric motor; an eccentric shaft portion that is provided on a protruding end portion of the rotor shaft that protrudes outside the housing; an external gear that is rotatably supported on the eccentric shaft portion via a bearing; an internal gear that is fixed to an outer surface of the housing and meshes with the external gear; and a transmitting portion that is provided on the external gear, and transmits rotation force to an external output shaft.