US Patent 11168709 Hydraulic drive device

Provided is a hydraulic drive device configured not to be increased in length in an axial direction. The hydraulic drive device is provided with a body portion for converting energy of a supplied pressure oil into rotational power, the body portion including an output shaft configured to rotate along a rotational axis by the rotational power, a hydraulic block disposed in an extending direction of the output shaft of the body portion and having an oil passage for supplying the pressure oil to the body portion, and a rotation sensor for detecting rotation of the output shaft, at least part of the rotation sensor being disposed in the hydraulic block.