COUNTER BALANCE VALVE AND FLUID PRESSURE CONTROL DEVICE PROVIDED WITH COUNTER BALANCE VALVE

摘要

A counterbalance valve (10) includes: a valve-side passage (14a,14b) communicating with the directional control valve (3); a motor-side passage (15a,15b) communicating with the fluid pressure motor (2); a control valve (11) configured to control flowing of working fluid between the valve-side passage (14a,14b) and the motor-side passage (15a,15b) when the directional control valve (3) is switched; a pilot chamber (11a,11b) to which pilot pressure for controlling the control valve (11) is guided; a pilot passage (13a,13b) communicating the valve-side passage (14a,14b) with the pilot chamber (11a,11b); and a flow rate control valve (12a,12b) configured to variably control a flow rate of working fluid flowing through the pilot passage (13a,13b).