Patent ID: 7847447

Claim:
A rotary actuator comprising: an electric motor composed of a rotor having a rotor shaft and a rotor core connected to the rotor shaft and a cylindrical stator including a stator core and stator coils, the stator core having stator teeth formed at a radially inner side thereof, the stator coils being wound around the stator teeth extending toward the rotor, the electric motor generating a rotational torque for rotating the rotor shaft; an eccentric portion integrally formed with the rotor shaft, the eccentric portion being formed to be eccentric with respect to a rotational axis of the rotor; and a speed reduction device having a sun gear rotatably supported on the eccentric portion, the sun gear having outer teeth formed on an outer periphery thereof, and a ring gear made of a magnetic material having inner teeth engaging with the outer teeth of the sun gear, the speed reduction device outputting a rotational torque transmitted from the rotor shaft by reducing a rotational speed, wherein: the cylindrical stator of the electric motor abuts the ring gear in an axial direction of the rotor shaft, such that a portion of the stator core located on a radially outer side of the stator coils is in contact with the ring gear, the front housing is made of a resin material, the front housing includes a metal plate partly embedded in the front housing, the ring gear is forcibly inserted into the metal plate, and the ring gear includes a cylindrical portion directly abutting the cylindrical stator.