A new means of achieving a valve float position in a closed centered hydraulic control valve. The valve has a main spool position whereby pressure compensator load sense control pressure is drained to tank through the main spool. Secondly, a pin acts on the pressure compensator to prevent the main pump flow from reaching the main section spool. Finally, the new spool position adds a connection from the consumer to tank, enabling a float position.

A new means of achieving a valve float position in a closed centered hydraulic control valve. The valve has a main spool position whereby pressure compensator load sense control pressure is drained to tank through the main spool. Secondly, a pin acts on the pressure compensator to prevent the main pump flow from reaching the main section spool. Finally, the new spool position adds a connection from the consumer to tank, enabling a float position.

The present disclosure provides, in a first aspect, a pressure-controlled 2-way flow control valve for hydraulic applications, wherein the 2-way flow control valve has applied thereto a first pressure signal in the closing direction of the 2-way flow control valve by means of a first output-side tapping and a second pressure signal in the opening direction by means of an LS pressure reporting duct. A pressure signal corrupting the first or second pressure signal is applied to the 2-way flow control valve in the closing or opening direction by means of a second tapping which is effective at least over part of the control stroke of the 2-way flow control valve.

A multi-actuation system includes a first electrohydraulic servo valve and a first actuator. A first fluid line fluidically connects the first electrohydraulic servo valve to the first actuator. The multi-actuation system also includes a second electrohydraulic servo valve and a second actuator. A second fluid line fluidically connects the second electrohydraulic servo valve to the second actuator. A ring fluidically connects the first fluid line with the second fluid line.

There is provided a hydraulic driving device for working machine having operability handling a change in burden weight in a front working device due to a loaded burden and the like when the working machine that accumulates energy in an accumulator and recovers and regenerates the energy performs an operation of lowering the front working device. A hydraulic driving device 5 includes a main pump 101, a boom cylinder 3, a tank 20, a flow rate control valve 6, an accumulator 300, a first differential pressure control valve 201, and a second differential pressure control valve 202. The first differential pressure control valve 201 is located between the boom cylinder 3 and the accumulator 300. The first differential pressure control valve 201 performs control on discharge oil from the boom cylinder 3 such that a differential pressure between before and after the flow rate control valve 6 becomes a target differential pressure. The second differential pressure control valve 202 is located between the accumulator 300 and the tank 20. The second differential pressure control valve 202 performs control on the discharge oil such that a differential pressure between an upstream pressure and a downstream pressure of the flow rate control valve 6 and the first differential pressure control valve 201 becomes the target differential pressure. The first and the second differential pressure control valves 201 and 202 are configured such that the target differential pressure increases according to an increase in pressure of the discharge oil.

This disclosure describes techniques for a self-aligning system within a belt-driven linear actuator that enables a keyless or round profile piston to be sealed while maintaining an aligning and/or torque resisting ability. This enables the airspaces within the electromechanical actuator could be pressurized to perform a secondary load holding function that is redundant to the linear screw device.

A multi-actuation system includes a first electrohydraulic servo valve and a first actuator. A first fluid line fluidically connects the first electrohydraulic servo valve to the first actuator. The multi-actuation system also includes a second electrohydraulic servo valve and a second actuator. A second fluid line fluidically connects the second electrohydraulic servo valve to the second actuator. A ring fluidically connects the first fluid line with the second fluid line.

A hydraulic system in of a work machine includes a hydraulic pump to supply pilot hydraulic oil in a hydraulic oil reservoir. A travel pump is to drive a travel motor according to a pilot pressure of the pilot hydraulic oil. A target pilot pressure of the pilot hydraulic oil is input through a travel operation device to control, according to the target pilot pressure, the pilot pressure supplied from the hydraulic pump to the travel pump. A pilot oil path connects the travel operation device and the travel pump to supply the pilot pressure to the travel pump. A drain oil path is divided from the pilot oil path. A pressure adjustment valve is provided in the drain oil path to adjust the pilot pressure to be less than the target pilot pressure when a condition is satisfied.

A valve subassembly includes a pump connection location, a tank connection location, and two constantly adjustable direction control valves each with first and second operating connection locations and an input connection location. A first valve group includes one direction control valve whose input is connected in parallel to two separate pump lines such that pressurized fluid is directed exclusively from the two pump lines to the control connection location. The two pump lines include a maximum of a first pump line and each remaining pump line is a second pump line. The maximum one first pump line is directly connected to the pump connection location in fluid terms, and a separate constantly adjustable pump valve is associated with each second pump line. Pressurized fluid is directed from the pump connection location via the pump valve into the associated second pump line.

A hydraulic drive system (1) including a meter-in compensator (37) and a bleed-off compensator (42) comprises a plurality of sensors (64 to 68), a controller (62), and an outlet pressure switching valve (61). The controller (62) determines whether or not the state of a wheel loader (2) which is detected based on the signals output from the sensors (64 to 68) meets a predetermined steering limiting condition. When the controller (62) determines that the state of the wheel loader (2) meets the steering limiting condition, it outputs a command signal to the outlet pressure switching valve (61). The outlet pressure switching valve (61) reduces the flow rate of the hydraulic oil flowing to steering cylinders (18L, 18R), in response to the command signal in such a manner that the flow rate becomes lower than that corresponding to the operation amount of a handle of a steering device (35).