| CPC F15B 11/161 (2013.01) [F15B 11/028 (2013.01); F15B 2211/25 (2013.01); F15B 2211/605 (2013.01); F15B 2211/6653 (2013.01)] | 6 Claims |
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1. A hydraulic system, comprising:
a variable displacement hydraulic pump;
a control valve configured to control a supply state of a hydraulic fluid from the hydraulic pump to a hydraulic actuator;
a sensing oil passage configured to extract a pilot hydraulic fluid portion branching from the hydraulic fluid being supplied from the control valve to the hydraulic actuator;
a pump operating unit configured to control a discharge amount of the hydraulic pump to an increase side in response to increasing of a pressure of the pilot hydraulic fluid portion in the sensing oil passage and to control the discharge amount of the hydraulic pump to a decrease side in response to decreasing of the pressure of the pilot hydraulic fluid portion in the sensing oil passage; and
an operating valve provided in the sensing oil passage, and
wherein:
the operating valve is switchable between an open state allowing the sensing oil passage to be open and a closed state blocking the pilot hydraulic fluid portion from flowing toward the control valve in the sensing oil passage,
the operating valve is maintained in the open state while an operation pressure is less than a setting pressure, and the operation pressure is a pressure of the pilot hydraulic fluid portion in a portion of the sensing oil passage which portion is between the operating valve and the control valve, and
the operating valve is switched to the closed state in response to increasing of the operation pressure to the setting pressure or more.
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