A hydraulic system for a working vehicle includes a first hydraulic pump to deliver pilot fluid to a control valve for a hydraulic actuator whose highest load pressure acts on a first fluid passage, and a second hydraulic pump to deliver hydraulic fluid whose pressure acts on a second fluid passage. A hydraulic controller is operable to control a load-sensing (LS) differential pressure between the highest load pressure and a delivery pressure of the hydraulic fluid from the second hydraulic pump. A third fluid passage to which the second hydraulic pump delivers the hydraulic fluid branches to a fourth fluid passage for flow of the pilot fluid. A solenoid valve is operable to change a pilot pressure of the pilot fluid for the hydraulic controller, and a controller is configured or programmed to control the solenoid valve to adjust the pilot pressure to change the LS differential pressure.

A hydraulic system for a working vehicle includes a first hydraulic pump to deliver pilot fluid to a control valve for a hydraulic actuator whose highest load pressure acts on a first fluid passage, and a second hydraulic pump to deliver hydraulic fluid whose pressure acts on a second fluid passage. A hydraulic controller is operable to control a load-sensing (LS) differential pressure between the highest load pressure and a delivery pressure of the hydraulic fluid from the second hydraulic pump. A third fluid passage to which the second hydraulic pump delivers the hydraulic fluid branches to a fourth fluid passage for flow of the pilot fluid. A solenoid valve is operable to change a pilot pressure of the pilot fluid for the hydraulic controller, and a controller is configured or programmed to control the solenoid valve to adjust the pilot pressure to change the LS differential pressure.

A hydraulic system may include a first actuator to control a first linkage member, a second actuator to control a second linkage member, a first primary hydraulic circuit and a first secondary hydraulic circuit that include the first actuator, a second primary hydraulic circuit and a second secondary hydraulic circuit that include the second actuator, a first pump to cause fluid to flow through the first primary hydraulic circuit and the second secondary hydraulic circuit, a second pump to cause fluid to flow through the second primary hydraulic circuit and the first secondary hydraulic circuit, and a controller. The controller may be configured to determine that an operator assistance mode is enabled, and cause closing of a first valve that controls fluid flow through the first secondary hydraulic circuit and a second valve that controls fluid flow through the second secondary hydraulic circuit.

A hydraulic system for a working machine, the system comprising: an electric machine connected to a first hydraulic machine and to a second hydraulic machine via a common axle, an output side of the second hydraulic machine being connected to an input side of the first hydraulic machine, wherein the first hydraulic machine is a variable displacement hydraulic machine with unidirectional flow; at least one hydraulic consumer hydraulically coupled to an output side of the first hydraulic machine via a supply line and configured to be powered by the first hydraulic machine; a first return line hydraulically coupling the hydraulic consumer to the input side of the first hydraulic machine.

A hydraulic system for a working machine, the system comprising: an electric machine connected to a first hydraulic machine and to a second hydraulic machine via a common axle, an output side of the second hydraulic machine being connected to an input side of the first hydraulic machine, wherein the first hydraulic machine is a variable displacement hydraulic machine with unidirectional flow; at least one hydraulic consumer hydraulically coupled to an output side of the first hydraulic machine via a supply line and configured to be powered by the first hydraulic machine; a first return line hydraulically coupling the hydraulic consumer to the input side of the first hydraulic machine.

The present invention relates to a hydraulic system for a hydraulically actuable work machine that comprises a switching valve block having a plurality of valve block inputs for a respective connection to a pressure output of one or more hydraulic fluid pumps; having a plurality of valve block outputs for outputting a pressurized hydraulic fluid; and having at least one valve that is arranged between valve block inputs and valve block outputs and that is adapted to selectively produce a fluid connection between a first valve block input and a first valve block output or between the first valve block input and a second valve block output; a plurality of pressure sources, preferably a plurality of separately controllable pressure sources of which each one is connected to a respective valve block input; and a plurality of hydraulic consumers of which each one is connected to a respective valve block output. The system is characterized in that the first valve block output furthermore already has a fixed fluid connection, preferably a fixed exclusive fluid connection, to a second valve block input and in that the steering is connected to the first valve block output.

The present invention relates to a hydraulic system for a hydraulically actuable work machine that comprises a switching valve block having a plurality of valve block inputs for a respective connection to a pressure output of one or more hydraulic fluid pumps; having a plurality of valve block outputs for outputting a pressurized hydraulic fluid; and having at least one valve that is arranged between valve block inputs and valve block outputs and that is adapted to selectively produce a fluid connection between a first valve block input and a first valve block output or between the first valve block input and a second valve block output; a plurality of pressure sources, preferably a plurality of separately controllable pressure sources of which each one is connected to a respective valve block input; and a plurality of hydraulic consumers of which each one is connected to a respective valve block output. The system is characterized in that the first valve block output furthermore already has a fixed fluid connection, preferably a fixed exclusive fluid connection, to a second valve block input and in that the steering is connected to the first valve block output.

A working fluid supply system is provided with: a first oil pump and a second oil pump driven by an engine; a switching valve configured to cause a discharge passage of the second oil pump to communicate with at least one of a supply passage and a first drain passage; and a controller configured to switch the switching valve. The controller is configured to switch the switching valve by spending a switching time that is set in accordance with a degree of pressure variation predicted to be caused in the supply passage when the switching valve is switched instantaneously.

A working fluid supply system is provided with: a first oil pump and a second oil pump driven by an engine; a switching valve configured to cause a discharge passage of the second oil pump to communicate with at least one of a supply passage and a first drain passage; and a controller configured to switch the switching valve. The controller is configured to switch the switching valve by spending a switching time that is set in accordance with a degree of pressure variation predicted to be caused in the supply passage when the switching valve is switched instantaneously.

Provided is a hydraulic circuit, for a construction machine, which drives an actuator by merging pressure oil from a fixed-volume pump into a center bypass oil path from a variable-volume pump to an oil tank, wherein the flow rate of flow from the fixed-volume pump to the center bypass oil path can be controlled in accordance with a requested flow rate of the actuator. A distribution direction-switching valve, which has a first oil path from a fixed-volume pump to an oil tank and a second oil path from the fixed-volume pump to a first center bypass oil path, has a first signal reception unit which causes a spool to slide in a direction in which the first oil path is formed, and a second signal reception unit which causes a spool to slide in a direction in which the second oil path is formed, and determines a distribution ratio of pressure oil flowing to the first oil path and the second oil path in accordance with the difference in size of the signals received by the first signal reception unit and the second signal reception unit, the first signal reception unit receiving a signal based on a negative control signal.