Patent ID: 8517138

Claim:
A hydraulic motor unit comprising: a hydraulic motor; a motor shaft that supports the hydraulic motor in a relatively non-rotatable manner with respect thereto; a motor housing that accommodates the hydraulic motor and supports the motor shaft in a rotatable manner around an axis line thereof; a volume adjusting mechanism that changes a volume of the hydraulic motor, wherein the volume adjusting mechanism includes a control shaft that is supported directly or indirectly by the motor housing in a rotatable manner around an axis line thereof in a state where a first end thereof is extended outward from the motor housing, and changes the volume of the hydraulic motor in accordance with rotation of the control shaft around the axis line; an electric motor including an electric motor main body that is electrically controlled; an electric motor case that accommodates the electric motor main body; an electric motor main body output shaft that is rotated around an axis line thereof by the electric motor main body, the electric motor case being detachably mounted to the motor housing; an operation shaft that is connected to the first end of the control shaft in a relatively non-rotatable manner with respect thereto; a sector gear that has a proximal end connected to the operation shaft and a distal end provided with a gear and extends in a direction perpendicular to the control shaft; and an electric motor cover to which the electric motor case is connected and which is detachably connected to the motor housing, wherein mounting of the electric motor to the motor housing causes the electric motor main body output shaft to be operatively connected to the first end of the control shaft so that the control shaft is rotated around the axis line in accordance with rotation of the electric motor main body output shaft, wherein the electric motor includes an electric motor output gear operatively connected to the electric motor main body output shaft, and wherein the electric motor output gear is directly or indirectly supported by the electric motor case so that the electric motor output gear is engaged with the sector gear upon connection of the electric motor cover to the motor housing.