Hydraulic circuit including pressure compensating valve

摘要

A hydraulic circuit including a pressure compensating valve, which aims at preventing the delay in operation of the valve due to the time required for the inflow of fluid in amount corresponding to stroke volume thereof, thereby improving the response of thereof. This hydraulic circuit includes a pressure compensating valve (3) provided between the delivery side of a hydraulic pump (1) and the inlet of a directional control valve (4), the pressure compensating valve (3) being arranged to be urged by the pressure applied to first pressure receiving portion (6) to position (D) where the area of opening thereof is kept maximum, and also urged by the pressure applied to second pressure receiving portion (8) to position (E) where the area of opening thereof is kept minimum, the portions (6) and (8) being connected with the outlet and inlet sides of the valve (4). The circuit includes a hydraulic cylinder (30) adapted to push the valve (3) to the position (D) and whose piston elongating chamber (31) is connected with an exterior pressurized fluid supply (11) and whose piston retracting chamber (34) is connected with the portion (6) so that when the valve (4) is located at neutral position (A) the valve (3) is held at position (D).