Patent ID: 7686725

Claim:
A reduction gear comprising: a motor including, an input shaft, a rotor rotating in conjunction with the input shaft, a stator, and a coil wound around the stator; a reduction mechanism including, an external gear eccentrically rotatable about an input shaft, an internal gear internally meshing with the external gear and having a small number of difference between the teeth of the internal gear and the external gear, a extracting member for extracting only a rotational component of the external gear, an output shaft, and a transmitting member for transmitting the rotational component of the external gear from the extracting member to the output shaft; and a positioning plate sandwiched between the reduction mechanism and the motor, wherein the positioning plate has a hole for receiving a thickness of the coil, the extracting member, the transmitting member, and the output shaft are aligned in a direction perpendicular to an axial direction of the input shaft, and the output shaft and the input shaft are not aligned on an identical axis.