PISTON-FORMAT WORKING-FLUID-PRESSURE ACTUATOR AND CONTROL VALVE

摘要

[Problem] To provide a piston-format working-fluid-pressure actuator capable of being used as a constituent part when used as either a reverse-action or forward-action piston-format working-fluid-pressure actuator, and also allowing a reduction in length along the direction in which an output shaft moves forward and backward, and to provide a control valve using the piston-format working-fluid-pressure actuator and a valve member. [Solution] A piston-format working-fluid-pressure actuator (10) has a casing (30) provided with a cover section (31) and a body section (32) and having a cylinder chamber (33) formed therein, an output shaft (40) supported by the casing so as to be capable of forward and backward movement, a piston (50) attached to the output shaft and partitioning the interior of the cylinder chamber, a spring member (60) biasing the piston with elastic force that causes the output shaft to move, and a working-fluid supply opening (70) for supplying working fluid. The piston is provided with an accommodating recess (51) in which the spring member is accommodated, the piston being mountable on the output shaft with the opening (52) of the accommodating recess selectively facing either the cover section or the body section.