Patent ID: 8035262

Claim:
A drive unit, comprising: a motor being a drive source for rotating a member to be rotated; a velocity reduction gear for reducing a revolution of the motor; an output shaft for connecting the velocity reduction gear to the member to be rotated; a velocity detection mechanism including an encoder, an encoder attachment bracket, and a sensor member for detecting a revolution of the output shaft by detecting a corresponding revolution of the encoder, wherein the velocity reduction gear and the velocity detection mechanism are placed in a unit housing including a housing body with an opening formed at one end and a support plate closing the opening; the output shaft is rotatably supported by the housing body and the support plate; wherein the encoder attachment bracket is mounted on the output shaft and comprises an encoder mounting portion for mounting the encoder thereon and a flange portion for providing a partition between the encoder and the velocity reduction gear; and the encoder is attached to the encoder mounting portion of the encoder attachment bracket with the flange portion positioned between the encoder and the velocity reduction gear to protect the encoder and the sensor member from foreign matter originating from the velocity reduction gear.