Electro-hydraulic actuator

An electro-hydraulic actuator, comprising:

• a motor configured to output rotative power;
• an external gear pump configured to be activated by the motor;
• a hydraulic actuator configured to be operated by a pressurized working fluid supplied by the external gear pump;
• a manifold block in which a flow channel forming one portion of a working fluid circuit of the hydraulic actuator is incorporated;
• a first portion configured to store the motor;
• a second portion configured to store the external gear pump, the hydraulic actuator, and a reservoir;
• and
• a coupling portion separable from the manifold block, configured to couple the first portion and the second portion with each other in a liquid-tight state, wherein
• the coupling portion includes a communication hole through which the first portion and the second portion communicate with each other and a flow channel forming another portion of the working fluid circuit is formed,
• a rotational shaft of the motor and a driving shaft of the external gear pump are joined to each other in the communication hole,
• a solenoid valve configured to open and close the flow channel formed in the coupling portion, wherein the solenoid valve is arranged outside the reservoir, and
• the external gear pump is attached to the coupling portion while being stored in manifold block, the manifold block being immersed in the working fluid.