Reduction device

A reduction device, comprising:

• a bracket having a gear storage recess with one surface opened;
• a reduction mechanism stored in the gear storage recess;
• and
• a guide part closing the one surface of the gear storage recess,
• wherein the reduction mechanism comprises:
• an internal gear being annular and having first internal teeth;
• an eccentric shaft arranged coaxially with an axis of the internal gear and rotating upon receiving external power;
• an oscillating gear rotatably supported on the eccentric shaft, and having first external teeth meshed with the first internal teeth and having second internal teeth;
• and
• an output part arranged coaxially with the axis and having second external teeth meshed with the second internal teeth,
• wherein the eccentric shaft comprises:
• a shaft body rotating around the axis;
• and
• an eccentric part provided on the shaft body and being eccentric with respect to the axis,
• wherein the oscillating gear is rotatably supported on the eccentric part,
• wherein the reduction device comprises at least one of a first engagement part provided on the guide part and the internal gear and concavo-convex fitting the guide part and the internal gear, and a second engagement part provided on the bracket and the internal gear and concavo-convex fitting the bracket and the internal gear,
• wherein the internal gear is pressed by the guide part from a one surface side of the gear storage recess.