Disclosed is a railway braking system including a control device having a valve with a body having a cavity and a slide having an internal chamber, supply notches and drainage notches each having an overall passage cross-section for a pressure medium having a shape exhibiting an apex, and being movably mounted in the cavity, between a supply position where the supply notch is opposite a supply groove of the body, and a drainage position where the drainage notch is opposite a drainage groove of the body; the device being configured to allow a substantially stable control configuration, wherein the pressure value of the medium is limited, and wherein the slide is positioned in the cavity such that a control notch of the slide is opposite a control groove of the body while the supply and drainage notches are respectively at a distance from the supply and drainage grooves.

A pilot hydraulic system may include a pilot pressure source, a pilot pressure return tank, a pilot valve, a pilot pressure supply line connecting the pilot pressure source to the pilot valve, and a pilot pressure return line connecting the pilot pressure return tank to the pilot valve. A main control valve may include a pilot chamber. A pilot pressure control line connects the pilot valve to the pilot chamber. A hydraulic sub-system is provided for modifying pilot pressure provided to the pilot chamber of the main control valve. The hydraulic sub-system may include a variable orifice valve disposed in the pilot pressure control line, a pilot pressure bypass line communicating the pilot pressure control line downstream of the variable orifice valve with the pilot pressure return line, and an electrohydraulic pressure reducing valve (EHPRV) disposed in the pilot pressure bypass line.

A load sense pressure regulating system is provided. The load sense pressure regulating system can be operable between a flow regulation mode and a pressure limiting mode. When the load sense pressure control system is in the flow regulation mode, flow between a load sense inlet and a pilot vent are metered by a main poppet. The load sense pressure regulating system can also include a control valve downstream from the pilot vent that is configured to control a relief setting of a relief valve to regulate the load sense pressure within a desired operating range.

A method for operating a hydraulic valve of a hydraulic device of a motor vehicle transmission device, wherein an actuating current of the hydraulic valve is superposed with a modulation alternating current in order to adjust a shaking vibration of the hydraulic valve by a control device, wherein a deviation between an actual pressure resulting from the actuating current and a setpoint pressure determined as a function of the actuating current is determined for the hydraulic device by means of an electronic computing device, and an amplitude and/or a frequency of the modulation alternating current is increased as compared to a starting value equalizing a hysteresis of the actual pressure relative to the setpoint pressure, as a function of a tolerance range being exceeded by the determined deviation.

A method is for controlling an actuation force exerted by an actuating device having a first working chamber and a second working chamber supplied with pressurized air from a source of pressurized air by a first pressure regulator and a second pressure regulator. The method includes calculating, by an optimization algorithm based on a dynamic model of the actuating device and of the first and second pressure regulators, desired values for control signals for the first and second pressure regulators to generate an actuation force equal to a desired value for the actuation force. An estimated value for the actuation force, estimated values for pressures inside the first and second working chambers and for first derivatives of the pressures, are determined by a state observer based on a measured value for the actuation force and on measured values for the pressures in the first and second working chambers.

A hydraulic assembly for a vehicle transmission includes a hydraulic pump for providing a system pressure within a hydraulic circuit, a pressure accumulator for temporarily supplying pressure to the hydraulic circuit, and a valve assembly for charging the pressure accumulator after a predetermined pressure threshold value of the system pressure has been reached or exceeded. The valve assembly is hydraulically connected between the pump and the pressure accumulator.

A fluid control system for supplying fluid to a fluid consumer, having a valve module including a channel body to which a fluid switching valve, a fluid pressure regulator and a vacuum switching valve are attached, the channel body having a first fluid channel extending from a fluid input port to an input port of the fluid pressure regulator and having a second fluid channel extending from an output port of the fluid pressure regulator to an input port of the fluid switching valve, and having a third fluid channel extending from an output port of the fluid switching valve to a fluid consumer port, and having a first vacuum channel extending from a vacuum input port to an input port of the vacuum switching valve, and having a second vacuum channel extending from an output port of the vacuum switching valve to the fluid consumer port.

A hydraulic boosting and regulating system includes an intensifier circuit and a regulator and employs low leak, low crossover valves.

A braking system for a vehicle may include a regulating device disposed between a braking device and a pressure agent source that causes the braking device to move. The regulating device may include a slide having an internal chamber with a supply port, a venting port, and a regulating port opening into the internal chamber and through which a pressure agent from the pressure agent source may flow. The regulating port can be located between the supply port and the venting port. Each of the supply port and the venting port may have a general cross-section for passage of the pressure agent substantially having a shape with at least one apex.

Provided is a work vehicle which can prevent an engine from stalling regardless of type of a system mounted on a vehicle body. In a wheel loader 1 equipped with a loading work device 11 operated by an electric operation lever 19, first and second directional control valves 5, 6 include neutral positions 5N, 6N for causing hydraulic oil discharged from a hydraulic pump 12 to return to a hydraulic oil tank 10, respectively, and in the case where a discharge pressure P of the hydraulic pump 12 is a main relief pressure Pr or more and an engine rotational speed N is less than a low idle rotational speed NL, a controller 2, 2A restricts the output of control signals to first and second solenoid control valves 3, 4 so as to cause the first and second directional control valves 5, 6 to be switched to the neutral positions 5N, 6N, respectively.