| 摘要 |
PROBLEM TO BE SOLVED: To suppress the generation of cavitation even in layout with long distance from an operating fluid tank to each hydraulic pump by providing hydraulic pump, an operating oil tank, a valve unit for controlling a hydraulic actuator device, and hydraulic piping for connecting the suction side of the pump to return the discharged operating fluid. SOLUTION: Operating fluid still pressurized, exhausted from a hydraulic steering control unit 3, that is a first hydraulic actuator device for controlling a hydraulic cylinder 4, is partially returned to the suction side of a steering hydraulic pump 1 of a first hydraulic pump, and to the suction side of a sprinkling pump driving hydraulic pump of a second hydraulic pump. Therefore the suction systems of the first and second hydraulic pumps are boosted up and pump suction negative pressure is partially reduced thereto. The generation of cavitation can therefore be suppressed, and there is no anxiety about an influence on hydraulic equipment. |
