HYDRAULIC TYPE CHANGEOVER DEVICE

摘要

PURPOSE: To improve the fine-controllability by setting up a control valve in a control pressure conduit. CONSTITUTION: A control pressure chamber 12 in a demand flow regulator 11 of a pump 1 is connected to a directional control valve 4 via a control pressure conduit 14, and a control valve 19 is set up in this control pressure conduit 14. With this, the control valve 19 works as a bias valve which reduces a pressure differentialΔP in the directional control valve 4 as far as the specified value so that the fine-controllability is thus improved.