Fluid pressure actuator unit

A fluid pressure actuator unit comprising:

• an electric motor;
• a fluid pressure pump comprising a discharge port and a suction port, which is driven by the electric motor to pressurize working fluid aspirated from the suction port and discharge the working fluid into the discharge port in a pressurized state;
• a fluid pressure cylinder that is operated by the working fluid supplied from the discharge port;
• a tank that stores the working fluid;
• a suction passage that connects the suction port to the tank;
• a flow restrictor provided in the suction passage;
• and
• a change-over valve that connects the discharge port to the tank when a differential pressure between the discharge port and the suction port is not greater than a predetermined pressure, and connects the suction port to the tank by bypassing the flow restrictor while disconnecting the discharge port from the tank when the differential pressure is greater the predetermined pressure.