HYDRAULIC CONTROL CIRCUIT AND HYDRAULIC FORMING MACHINE

摘要

PROBLEM TO BE SOLVED: To provide a hydraulic control circuit to vary a flow rate and the pressure of working oil fed to a hydraulic actuator and simplify constitution of a pump unit and reduce size and to provide a forming machine utilizing the hydraulic control circuit. SOLUTION: This hydraulic control circuit comprises an air hydro converter 11 (a sealed container); a high pressure air feed source 14 (a pressurized air feeding means) to feed a pressurized air to the air hydro converter 11; a route Lf1 (a first route) to interconnect the air hydro converter 11 and a double acting hydraulic cylinder (a hydraulic actuator); a pump unit 12 (a pressurizing means) to pressurize working oil FL; a route Lf3 (a second route) to interconnect the pump unit 12 and the double acting hydraulic cylinder 2; and a cutoff valve 16 (a route switching means) to vary a connection state between the route Lf1 or the route Lf3 and the double acting hydraulic cylinder 2.