Electric motor, rotary actuator and rotary apparatus

1. A rotary actuator comprising:

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.

2. The rotary actuator according to claim 1 , wherein

the housing is closed off by a removable cover on the opposite side of the housing from the side where the eccentric shaft portion is provided; and

a recessed portion that removably holds a bearing that rotatably supports another end portion of the rotor shaft, is formed in an internal surface of the cover.

3. A rotary apparatus comprising:

the rotary actuator according to claim 1 ; and

an output mechanism that has the output shaft which is driven by the rotary actuator, an output side housing, and an output side transmitting portion, wherein

the output shaft is rotatably supported inside the output side housing;

one end portion of the output shaft penetrates a wall of the output side housing so as to protrude from the outer surface thereof; and

the output side transmitting portion provided on the protruded end portion of the output shaft, to which a rotation component of the external gear is transmitted as a result of the output side transmitting portion being removably connected to the transmitting portion of the external gear.