A hydraulic system for a working machine is a load sensing (LS) system and includes a first hydraulic actuator and a first control valve for controlling the flow of hydraulic fluid from a pump to the first hydraulic actuator and for draining hydraulic fluid from the first hydraulic actuator, respectively and a second hydraulic actuator and a second control valve for controlling the flow of hydraulic fluid from the pump to the second hydraulic actuator and for draining hydraulic fluid from the second hydraulic actuator, respectively. The hydraulic system further includes a first hydraulic circuit for providing an LS pressure for the first actuator and a second hydraulic circuit for providing an LS pressure for the second actuator. At least one of the first and second hydraulic circuits includes an offset valve for changing the LS pressure before providing the LS pressure to the pump.

A hydraulic system for a working machine is a load sensing system and includes a hydraulic actuator for movement of an implement and a control valve having an inlet valve and an outlet valve for controlling the flow of hydraulic fluid from a pump to the hydraulic actuator and for draining hydraulic fluid from the hydraulic actuator, respectively. The hydraulic system also includes an arrangement for determining the load on the hydraulic actuator. The hydraulic system further includes a valve for disconnecting the flow of hydraulic fluid from the pump to the hydraulic actuator, while allowing another flow of hydraulic fluid to the hydraulic actuator, provided that the determined load on the hydraulic actuator exceeds a threshold value.

An electrohydraulic control device for an adjustable hydraulic pump system includes a valve device, an electronic control unit and a first fluid sensor. The valve device includes a pressure inlet, a tank outlet and a first electromagnetically actuated valve. An outlet pressure of the first adjustable hydraulic pump system is applied to the pressure inlet. The first fluid sensor detects an actual value of a fluid parameter of the first adjustable hydraulic pump system and transmits it to the electronic control unit. The electronic control unit includes computer-based modeling of the dynamics of the first adjustable hydraulic pump system, and actuates the first electromagnetically actuated valve based on the actual value of the fluid parameter and the computer-based modeling.

A hydraulic actuator control system performs pressure compensation in the system by monitoring the pressure differential across a meter-out device. A flow of fluid can be directed from a pump through a meter-in device to a chamber of an actuator via a first port. In response to the flow of fluid entering the first port of the actuator, a return flow of fluid can be directed from a second port of the actuator through the meter-out device to a tank. The meter-in device can monitor a pressure differential across the meter-out device. The meter-in device can control the flow of the fluid from the pump to the actuator to place the pressure differential across the meter-out device within a desired range.

An electrohydraulic control device for an adjustable hydraulic pump system includes a valve device, an electronic control unit and a first fluid sensor. The valve device includes a pressure inlet, a tank outlet and a first electromagnetically actuated valve. An outlet pressure of the first adjustable hydraulic pump system is applied to the pressure inlet. The first fluid sensor detects an actual value of a fluid parameter of the first adjustable hydraulic pump system and transmits it to the electronic control unit. The electronic control unit includes computer-based modeling of the dynamics of the first adjustable hydraulic pump system, and actuates the first electromagnetically actuated valve based on the actual value of the fluid parameter and the computer-based modeling.

A valve (18), for a valve assembly (10) for regulating the pressure of a fluid guided in a hydraulic system for supplying pressure to at least one hydraulic consumer (12a, 12b), includes a pilot control stage (48) and a main control stage (38) for at least partially clearing or blocking a fluid path from a supply connection (P) to an outflow connection (T). A relief stage (54) for pressure relief of a fluid chamber is arranged between the pilot control stage (48) and the main control stage (38). The relief stage (54) compares the existing load pressure at load terminal (LS) dedicated to the hydraulic consumer (12a, 12b) with the outflow pressure at the outflow connection (T), clearing the pressure relief if both pressures are approximately the same. The relief stage (54) can be directly connected to the load connection (LS) and can be charged with load pressure.

A hydraulic system and method of controlling such on a machine is disclosed. The hydraulic system may comprise a primary hydraulic circuit that includes a first load sense controlled pump, a secondary hydraulic circuit that includes a second load sense controlled pump, a flow sharing valve, and a load sense arrangement. The load sense arrangement may include a main resolver configured to select a higher pressure signal between the primary and secondary hydraulic circuits, and a load sense valve having an open position at which pressure signal flow between the primary hydraulic circuit and the main resolver is allowed, and a closed position at which pressure signal flow between the primary hydraulic circuit and the main resolver is blocked. In an embodiment, when the load sense valve is in the closed position, the second load sense controlled pump may be controlled only by the secondary hydraulic circuit.

A floating control system for a fixed displacement pump system is disclosed, which relates to the technical field of floating mechanisms and includes: a fixed displacement pump, floating control valves, a floating mechanism, boom function valves, an actuator and a control device, where the fixed displacement pump, the floating control valves and the floating mechanism are connected in sequence, the fixed displacement pump, the boom function valves and the actuator are connected in sequence, the floating control valves include a pressure reducing valve and a floating switching valve, and the boom function valves include a fixed differential overflow valve and a proportional directional valve; and the fixed differential overflow valve and the proportional directional valve are connected in parallel between the fixed displacement pump and an oil return tank, the floating switching valve and the fixed differential overflow valve are connected through a feedback oil path.