Construction machine equipped with a hydraulic control device and the hydraulic control device

摘要

PROBLEM TO BE SOLVED: To provide a hydraulic controller which can retain attitude of an actuator when the attitude of the actuator is neutral, and to provide a construction machine which mounts the hydraulic controller thereon.SOLUTION: A hydraulic controller includes: a valve body 10 having a plurality of oil chambers which contain pressure oil supply channel 12a, cylinder ports 15a, 15b and tank ports 20a, 20b; a switching spool 13 which is inserted freely slidably and liquid-tightly into the valve body, supplies pressure oil supplied from the pressure oil supply channel to an actuator 38 via the cylinder ports and switches the supply and discharge of oil such that return oil from the actuator is discharged from the tank port to a tank line; a middle chamber 14 disposed between the pressure oil supply channel and the cylinder ports; and a notch 50a disposed on a part which joins the middle chamber of the switching spool to the cylinder ports of the side of contracting a hydraulic cylinder when the switching spool is arranged on the neutral neighborhood, in a direction switching valve having a check valve 17 disposed between the middle chamber and the cylinder ports.