A valve system for use with a cylinder having an extensible rod, includes first and second valve assemblies, each including an inlet/outlet port configured to selectively be coupled with a source of pressurized gas, a check valve biased toward a closed state and having a check valve body at least partially receivable within a first port of the cylinder, a flow control valve positioned in series between the inlet/outlet port and the check valve, and an inlet pilot port connected with the check valve for opening the check valve when supplied with pressurized gas. First and second pilot lines extend to the respective inlet pilot ports from respective outlet pilot ports of the opposite ones of the first and second valve assemblies. When pressurized gas is supplied to the inlet/outlet port of a valve assembly, pressurized gas is also supplied to the opposite inlet pilot port.

A work machine includes an electric drive system. The work machine includes a prime mover, a machine controller, and a hydraulic control system. The hydraulic control system includes a pump, a control valve and a retarding control valve. The pump is configured to supply pressurized fluid to the hydraulic control system via a supply line. The control valve is fluidly coupled to the pump via the supply line, and includes a pressure relief valve. The retarding control valve is fluidly connected to the pump and the control valve. The retarding control valve includes a solenoid valve, an orifice and a check valve. The solenoid valve is coupled to the machine controller, the orifice restricts a flow of the pressurized fluid through the supply line, and the check valve is coupled to a discharge line, which branches from a point along the supply line between the solenoid valve and the orifice.

The invention relates to a hydraulic steering device that hydraulically connects a steering cylinder to a supply system, whereby the supply system is hydraulically operatively connectable to the steering cylinder via a steering valve to form a main flow connection and the supply system is hydraulically operatively connectable to the steering cylinder via a flow regulation valve arrangement to form a branch flow connection that circumvents the main flow connection, whereby the flow regulation valve arrangement is triggerable by an electric control unit and the flow regulation valve arrangement comprises valve groups that are triggerable individually, which are respectively connected in the forward flow and return flow of the branch flow connection and a release-shutoff valve is assigned to the flow regulation valve arrangement. It is provided that the release-shutoff valve is connected between the flow regulation valve arrangement and the steering cylinder.

An electro hydraulic servo valve and a method of controlling pressure therein includes a first stage unit including a moveable direct drive valve, a second stage unit including a centering spring and a second stage spool valve that is fluidly connected to the moveable direct drive valve, and at least one pressure feedback fluid line fluidly connected to the first stage unit. The moveable direct drive valve selectively supplies fluid pressure to the second stage unit. Motion of the second stage unit is arrested using the centering spring and motion of the first stage unit is arrested when pressure is fed back to the first stage unit. A supply pressure or a return pressure is metered using the pressure feedback fluid line.

A hydraulic component includes a camera integrated such that the camera observes at least one surface that is prone to wear and/or at least one edge that is prone to wear to make a statement about wear relating to the at least one surface and/or the at least one edge.

A solenoid valve island having a base body that includes a housing for a respective solenoid valve, a main feeding duct that is in fluid communication with the housing to supply compressed air entering the solenoid valve and that is provided with an inlet mouth for connection with a source of compressed air, a main collection duct in fluid communication with the housing to collect air leaving the solenoid valve and a discharge mouth for discharging the collected air, a hollow seat in which an electric or electronic supply and control circuit of the solenoid valve is housed and includes an opening at each housing for the electric connection, through it, of the respective solenoid valve with the electric or electronic supply and control circuit, where the electric or electronic supply and control circuit has a male or female type power supply and signal transmitting connector that is partially housed in the hollow seat of the base body and that can be coupled with a corresponding end connector of a cable for the connection of the electric or electronic supply and control circuit to a remote supply and control unit, the corresponding end connector being respectively female or male.

The present disclosure relates to a method for controlling a swing motor in a hydraulic system and a hydraulic system. The method for controlling the swing motor in the hydraulic system and the hydraulic system according to the exemplary embodiment of the present disclosure may ensure the sufficient amount of hydraulic oil in a make-up line in a situation in which the hydraulic oil needs to be supplementarily supplied to the swing motor in the hydraulic system. Therefore, it is possible to prevent the occurrence of cavitation in the swing motor by stably supplying the amount of hydraulic oil at the point in time where the hydraulic oil needs to be supplementarily supplied to the swing motor. In addition, it is possible to prevent the occurrence of abnormal noise which is harsh to the ear when the cavitation occurs.

A method for operating a fluid system including the steps: receiving or determining a set value for a stroke of the working valve, determining an actual value for the stroke of the working valve using a sensor signal of a position sensor, determining a deviation value of a working valve in dependence on sensor signals of a supply pressure sensor and a working pressure sensor and a position sensor and a sensor system, and performing a processing of the set value for the stroke of the working valve, the actual value for the stroke of the working valve and the deviation value to a control signal for driving the working valve.

A proportional control fluid actuator that is used as a positioning device in applications such as a hydraulic directional control valve. The activating device has a cylinder body attachable to a valve body and has a bore carrying a piston that is coaxially secured to an end of a valve spool. The device is provided with spaced openings in the cylinder body that communicate with the bore therein to introduce fluid to act on opposite sides of the piston. Factory pre-compressed spring means are provided for normally urging the piston and spool to a center position. Since the areas of the fluid pressure applied on both sides of the piston are different (due to a spool on one side of the piston), two pre-compressed springs are used to compensate the area difference to achieve a proportional movement of the spool.

A hydraulic system includes first and second valve assemblies connected to a common pump. The first valve assembly includes a main valve housed inside a manifold. A pressure compensator valve maintains a constant pressure drop across a variable orifice of the main valve. A pressure limiter valve is in communication with the main valve and the pressure compensator valve, and allows an actuator connected to the first valve assembly to operate independently of the second valve assembly so that fluid flow to a work port of the first valve assembly is not interrupted by operation of the second valve assembly.