Hydraulic system for working machine
AssigneeKubota Corporation
InventorYuji Fukuda
Life of this patent
Estimating the term…
Abstract
A hydraulic system for a working machine includes a prime mover, a boom cylinder, a control valve, a first hydraulic pump to deliver pilot fluid to switch the control valve, a second hydraulic pump to deliver hydraulic fluid to activate the boom cylinder, a hydraulic controller configured or programmed to control the second hydraulic pump to set a load-sensing (LS) differential pressure, a first pilot fluid passage, a second pilot fluid passage branching off from the first pilot fluid passage and connected to the hydraulic controller, a solenoid valve to change a pilot pressure that is a pressure of the pilot fluid applied to the hydraulic controller, and a pressure compensator to increase the LS differential pressure as a temperature of the hydraulic fluid including the pilot fluid decreases.
Claims20
A hydraulic system for a working machine, the hydraulic system comprising:
- a prime mover;
- a hydraulic actuator;
- a control valve to control activation of the hydraulic actuator;
- a first hydraulic pump to be driven by power of the prime mover to deliver pilot fluid to switch the control valve;
- a second hydraulic pump to be driven by power of the prime mover to deliver hydraulic fluid to activate the hydraulic actuator, the second hydraulic pump being a variable displacement hydraulic pump;
- a hydraulic controller to control a delivery amount of the hydraulic fluid from the second hydraulic pump to set a load-sensing (LS) differential pressure, the LS differential pressure being a pressure difference between a delivery pressure of the hydraulic fluid from the second hydraulic pump and a highest load pressure of the hydraulic fluid when the hydraulic actuator is in operation;
- a first pilot fluid passage through which the pilot fluid delivered from the first hydraulic pump flows;
- a second pilot fluid passage branching off from the first pilot fluid passage and connected to the hydraulic controller;
- a solenoid valve in the second pilot fluid passage to change a pilot pressure of the pilot fluid applied to the hydraulic controller;
- and
- a pressure compensator located between the solenoid valve and the hydraulic controller to increase the LS differential pressure as a temperature of the hydraulic fluid including the pilot fluid decreases.
Dependencies are inferred from the claim text.