Patent ID: 8596058

Claim:
An hydraulic system, comprising: an oil tank storing operating oil; a main hydraulic actuator; a second hydraulic actuator which operates at a hydraulic pressure lower than or equal to a predetermined pressure; a hydraulic pump which draws the operating oil from the oil tank and supplies the operating oil to the main and second hydraulic actuators; a main tube which sends the operating oil from the hydraulic pump to the main hydraulic actuator; a second tube which sends the operating oil to the second hydraulic actuator; and an operating oil separating unit which is located at a midway point of the main tube and which separates a part of the operating oil supplied from the hydraulic pump to return the part of the operating oil to the oil tank, the operating oil separating unit comprising: a branch tube which branches out from the main tube; and a reducing valve having an inlet port connected to the branch tube, an outlet port connected to the second tube, and a relief port connected to the oil tank, wherein: the reducing valve reduces a pressure of the outlet port to be lower than or equal to a predetermined pressure by separating the part of the operating oil introduced from the inlet port to proceed from the relief port to the oil tank; and a flow amount of the operating oil separated by the reducing valve is set to a value which the hydraulic pump should maintain to reduce pulsation to be lower than or equal to a desired level.