To prevent the re-rolling of a hydraulic actuator when it is moved to stop state from driving state in a hydraulic control device for controlling the flow rate and pressure in meter-in and meter-out by a three-way valve and to smoothly shift the hydraulic actuator from turning condition to stop condition of turning.
In order to detect the stoppage of a hydraulic actuator A from the driving state, this device has a tachometer 44 for detecting the rotating speed of a load or a means for identifying the arithmetic flow rate on mater-in side, and a means for switching a three-way control valve 12 on meter-out side to a relief valve position c' until a fixed time passed after the stop of the hydraulic actuator A, or the load pressure on meter-out side detected by a pressure sensor 32 is a prescribed value or less.
SHINOHARA HIDEAKI
KAWASAKI HARUHIKO
