Abstract: The invention relates to a valve arrangement for actuating a load (2), having an infinitely variable directional control valve (3) acting as inlet throttle via which a pump connection (P) can be connected to load connections (A, B). The load (2) is connected via working lines (4, 5) to the directional control valve (3) and a discharge volumetric flow (6) of a pressure medium (7) from the load (2) can be adjusted via a throttle device (8) on the basis of a load signal (LS) of the load (2). The throttle device (8) can be adjusted by a dynamic pressure (p?) derived from the load signal (LS). The valve arrangement is characterised in that the throttle device (8) is actuated via a hydraulic circuit (17), which detects the magnitude and direction of a pressure medium flow (7) to the load (2).

Abstract: In a check valve assembly and a valve assembly employing such a check valve assembly, a topping piston may be taken into contact with a main poppet to raise the main poppet from its seat. The main poppet is designed without significant area difference from the valve seat and the topping piston is actuated through a pilot valve, so that the process of raising the main poppet from the valve seat is controllable.

Abstract: A valve assembly for actuation of a user and a method for actuation of the valve assembly, wherein a supply throttle device and a drain throttle device may be actuated independent of each other, is disclosed. In the case of single-action users, the drain throttle device is actuated such that the open cross-section of the drain throttle is maximum upon attaining the desired volumetric flow of hydraulic oil, so that the energy losses in the drain conduit are reduced to minimum.

Abstract: A valve assembly for pressure adapted and volumetric flow adapted supply of at least one user may be supplied with hydraulic fluid or connected to a tank via two work ports of a continuously adjustable directional control valve. To the two work ports of the valve assembly a common pressure compensator is associated, the piston of which is guided in axial translation in an axial bore of the directional control valve spool, so that one of the two work ports may optionally be connected to the pump port upon suitable actuation of the directional control valve. At both end surfaces of the directional control valve spool and at the spring side of the pressure compensator piston, there acts a respective control pressure which, for example, corresponds to the highest system load pressure, the individual load pressure, or a pressure derived therefrom.

Abstract: A directional control valve has snap-locking device for retaining the slide of the directional control valve in at least one switching position. The snap-locking device has a snap-locking part with a snap-locking piston that allows an engagement part to engage and lock the slide of the directional control valve. A kick-out device disengages the engagement part when a predetermined control pressure is exceeded. The kick-out device triggering force may be adjusted by a setting device that acts on a kick-out spring. A switching device that allows the kick-out function to be switched off independently of the setting of the setting device associated with the directional control valve in order to prevent disengagement independently of the initial stress of the kick-out spring.

Abstract: A valve arrangement for a hydraulic transmission circuit, in particular for a change-under-load transmission with a clutch valve arrangement for controlling at least one clutch and/or start-up clutch with the aid of a pressure-regulating valve whose normal position can be influenced mechanically by a clutch pedal. The pressure-measuring area of the pressureregulating valve is connected to a control valve whose piston, acted on by the clutch pedal, can be brought, against the force of a spring placed between the pressure-regulating valve and the control valve, first of all out of a position that relieves the pressure-measuring area of load into a floating position in which the pressure-measuring area is connected to the pressure-regulating valve outlet. Then, and after traversing a certain path, it can be brought into contact with the valve body of the pressure-regulating valve.