Electrohydrostatic actution system, hydraulic circuit of electrohydrostatic actution system, and steam turbine system including same

Abstract

Provided is an electrohydrostatic actuation system including an emergency shut-off circuit to be actuated stably with a simple configuration. The electrohydrostatic actuation system includes: a hydraulic cylinder () including a piston () to which a valve element is connected, a first chamber (A), and a second chamber (B); a hydraulic pump () configured to supply hydraulic fluid to the first chamber (A) or the second chamber (B); a servo motor (M) configured to drive the hydraulic pump (); a shuttle valve () configured to establish communication to a downstream side under a state in which a hydraulic pressure generated by the hydraulic pump () is maintained; a solenoid valve () configured to receive the hydraulic pressure via the shuttle valve () as a pilot pressure; and a logic valve () including a first port configured to receive the pilot pressure from the solenoid valve (), and a second port to be communicated to the first chamber (A) of the hydraulic cylinder (). When the solenoid valve () is brought to a de-energized state, the pilot pressure of the logic valve () is released, and the logic valve () causes the hydraulic fluid in the first chamber (A) communicated to the second port to flow into the second chamber (B) so that emergency shut-off of the valve element is achieved by a return spring ().