PURPOSE: To reduce the size of the whole of a system and improve recovery of energy by a method wherein pressure liquid delivered from two gear mechanisms for driving a pump is joined and fed to the actuator side and pressure liquid fed from the actuator side to the gear mechanisms is fed to only one gear mechanism by a check valve.
CONSTITUTION: The flow passage L6 of the gear mechanism P2 of a two-throw gear pump TP and the flow passage L5 of the gear mechanism PI are intercoupled through a check valve CV. The check valve CV causes the flow of delivery oil from a flow passage L6 to only the L5 side. Thus, the gear mechanisms P1 and P2 are rotated in the direction of an arrow mark and when pump function is provided, delivery oil from the gear mechanism P2 flows through the check valve CV to a flow passage 5 after the flow of it through a flow passage 6 and is joined with delivery oil in the flow passage 5 and fed through a flow passage L7 to an actuator 23. Reversely, pressure oil of the actuator 23 during recovery of energy is fed to only the gear mechanism P1 through the working of the check valve CV.
SERA YASUSHI
FUKUSHIMA NOBUHISA
