US Patent 11932323 Speed reducer, drive unit and steering assisting device

A speed reducer according to one aspect of the present disclosure includes an input rotating body, a speed reducing mechanism unit, and a tubular case. The speed reducer is rotatable when acted upon by power fed from a drive device. The speed reducing mechanism unit reduces a speed of rotation of the input rotating body. The tubular case covers an outer surface of the speed reducing mechanism unit and rotates when acted upon by speed-reduced power from the speed reducing mechanism unit. An output arm is formed integrally with the tubular case, the output arm extending radially outward from an outer peripheral surface of the tubular case and configured to transmit a manipulating force to an outside.