Patent ID: 11898327
Assignee: KUBOTA CORPORATION
Field: Mechanical elements (Mechanical engineering)
Classification: CPC E  F | IPC E  F

Claim 3:
4. A hydraulic system for a working machine, the hydraulic system comprising:
a first hydraulic pump to output a hydraulic fluid;
a second hydraulic pump to output a pilot fluid;
an operation device including an operation lever and at least one pilot valve to change a pressure of the pilot fluid supplied through a fluid passage in accordance with a direction in which the operation lever is operated and an amount by which the operation lever is operated;
at least one hydraulic actuator to be operated by the hydraulic fluid;
at least one pilot fluid passage connected to the at least one pilot valve;
a first control valve connected to the at least one pilot fluid passage to be operated by the pilot fluid to control a flow of the hydraulic fluid to be supplied to the at least one hydraulic actuator;
a second control valve to be operated by the pilot fluid to control a flow of the hydraulic fluid;
at least one proportional valve to change, to operate the second control valve, a pressure of the pilot fluid to be supplied to the second control valve;
a blocking switching valve capable of blocking the at least one pilot fluid passage connected to the at least one pilot valve and the first control valve;
at least one pressure sensor provided in the at least one pilot fluid passage to detect a pressure in the at least one pilot fluid passage, the at least one pressure sensor being located between the at least one pilot valve and the blocking switching valve; and
a controller configured or programmed to, after causing the blocking switching valve to operate to block the at least one pilot fluid passage, control the at least one proportional valve, based on the pressure detected by the at least one pressure sensor.