CONTROL DEVICE FOR FLUID PRESSURE ACTUATOR

摘要

PROBLEM TO BE SOLVED: To accomplish a suitable operation amount vs pressure or speed modulation characteristic for a fluid pressure actuator in a meter-in/meter-out separation type control circuit. SOLUTION: A bridge circuit 3 comprising meter-in valves A1IMV, A2IMV and meter-out valves A3IMV, A4IMV is provided between a pump 1 and a fluid pressure actuator 2. The meter-in valves A1IMV, A2IMV have a meter-in spool 36 for contraction-controlling an operation fluid at a contraction of area and a spring 55 for urging the meter-in spool 36 to a close direction. A donut area-shaped load pressure-receiving surface 47 for receiving a load pressure (PL) fed back from the fluid pressure actuator side 2 and generating a force for urging the meter-in spool 36 to a close direction and a pilot pressure function surface 45 for receiving a control intermediate pressure (Pc) relating to an operation amount introduced from a pilot valve 17 and generating a force for urging the meter-in spool 36 to a close direction are formed on the meter-in spool 36.