Abstract: A pressure control device has at least two switching valves (10, 12), a feedback control unit (14), a sensor unit (20), and a voltage supply unit (24), and continuously adjusts hydraulic systems.

Abstract: A system for charging and discharging at least one hydraulic accumulator (10) can be connected to a valve control device (12). The valve control device (12) has at least one logic valve (14). A shuttle valve (16) and a hydraulically operated switching valve (18) are also provided. The valves (14, 16, 18) are interconnected such that the hydraulically actuatable switching valve (18) compares the accumulator pressure (pA) to a minimum accumulator pressure (pA0) that can be adjusted via the control pressure setting of this switching valve (18).

Abstract: A device includes a regulating piston (12) guided longitudinally movably in a housing (10) and interacting with a control edge (56), at a pressure supply port (P) that supplies a utility port (A) in regulating positions of the regulating piston (12) with fluid. The pressure can be preset via a fluid connection, pulling the regulating piston towards a closed position blocking this fluid connection due to occurring flow forces. The regulating piston (12) has a change of shape (60) from its general outer basic shape in the area of the control edge (56) of the housing (10) for a flow force compensation. A flow contact surface for fluid is provided causing a compensating force acting against the flow force to be introduced into the regulating piston (12), which flow force pulls the regulating piston (12) into an open position opposite from the blocked position.

Abstract: A valve, in particular for use as a pressure compensator or maintenance-type component (38) in hydraulically actuated hoisting devices (2), has a valve housing (54) with a control port (40), a fluid inlet (64) and a fluid outlet (66). A regulating piston (68) is longitudinally displaceably in the valve housing (54) and acts against an energy storage device (70) in the form of a compression spring, bringing the regulating piston (68) into positions forming a fluid-conveying connection between the fluid inlet (40) and the fluid outlet (66) or blocking this connection by a control pressure existing at the control port (40). A first orifice (88) in the regulating piston (68) connects the control port (40) to a receiving space (62) for the energy storage device (70) in a fluid-conveying manner. A second orifice (90) is in an intermediate part (72) in the valve housing (54).

Abstract: A discharge pressure scale (30) includes a valve housing (41) having a functional connector (A), a return flow connector (T) and a user connector (28). A valve piston (52) is guided such that it moves longitudinally against the effect of an energy accumulator (42), moving from a respective opening or regulating position, against a valve seat (94), into a closed position. The user connector (28) and return flow connectors (T) are separated from one another. The fluid pressure present at the user connector (28) can be guided onto a pressure-active surface (A1*) of the valve piston (52) by a pressure compensation device (70) in such a way that it moves into its respective opening or regulating position in a pressure-compensated manner due to the force of the energy accumulator (42).

Abstract: A control piston (12) is longitudinally displaceable in a housing (10) having two connection points (P, A) for fluid, and cooperates with a metering edge (34) of the housing (10) at a connection point (P). Point (P), in control positions of the control piston (12), supplies the connection point (A) with fluid via a fluid connection. The piston, as a result of occurring flow forces, tends to be drawn in the direction of a closing position that blocks one of these fluid connections. To compensate the flow force, the control piston (12) has, in the region of the control edge (34) of the housing (10), a shape modification (48) of its cylindrical exterior basic form (50), such that a flow contact surface (52) for fluid is created. The contact surface transfers a compensating force that acts against the flow force to the control piston (12) and that seeks to pull the control piston (12) into an opening position opposed to the closing position.

Abstract: A valve, in particular a 4/2-way slide valve (60), includes a valve piston (67), which is guided in a longitudinally movable manner in a valve housing (25), for selectively connecting and disconnecting fluid connections in the valve housing (25), such as a pressure supply connection (P), a tank connection (T), and two utility connections (A, B). A magnetic system (49), to which current can be supplied, controls the valve piston (67). When no current is supplied to the magnetic system (49), the control pressure at one of the utility connections (A, B) can be set, in particular limited, by a control device (62, 70, 79, 80, 88) arranged in the valve housing.

Abstract: A hydraulic hybrid system for rotatory applications has an actuator (49, 91) in the form of a motor pump unit (91). The motor pump unit is coupled to a rotatory-operating device (94) and works as a consumer of hydraulic energy in one operating state of the device (94) and works as a producer of hydraulic energy in another operating state of the device (94). A hydraulic accumulator (1) can be charged by the motor pump unit (91) for energy storage in the one operating state and can be discharged for energy release to the motor pump unit (91) in the other operating state. The hydraulic accumulator is an adjustable hydropneumatic piston accumulator (1) in which a plurality of pressure chambers (19, 21, 23, 25) are delimited by active surfaces (11, 13, 15, 17) of different sizes on the fluid side of the accumulator piston (5).

Abstract: A pressure-regulating valve has a valve piston (10) subjected to the action of an energy store and guided longitudinally in a valve housing (12). The valve housing has a supply port (14), a utility port (16) and a tank port (18) actuated by a control part (20) closing with a sealing action. In connecting from the supply port to the utility port, a pressure reduction function is realized. In a fluidic connection from the utility port to the tank port, a pressure-limiting function is realized. The control part (20) has a control rod (22) with two control bodies (24, 26) spaced apart from one another. One control body (24) controls the connection between supply port (14) and utility port (16). The other control body (26) controls the connection between utility port (16) and tank port (18).

Abstract: A valve device for controlling a fluid flow includes a flow control valve (15) having a valve housing (19) with a supply connection (9) and a user connection (11). A valve piston (17) is guided inside the valve housing (19) longitudinally moveable and controls the passage to the user connection (11) by a thermocouple (61) via an orifice (37, 39) depending on the temperature of the fluid flow. A pressure compensator (21) is connected to the supply connection (9) and keeps the pressure drop across the orifice (37, 39) constant.

Abstract: A proportional pressure regulating valve has a spring-loaded valve piston (10) guided in and actuated by an actuating magnet (14) within a valve housing (12). Opposite valve piston sides are exposed to tank pressure. The valve piston (10) has a regulation surface (44) connectable to working port (A) for a regulation pressure (PR). A ring-shaped chamber (42) in the valve housing (10) opens into the working port (A). At the transition between the ring-shaped chamber (42) and the working port (A), the regulation surface (44) is active. When the actuating magnet (14) is deenergized, a maximum regulation pressure (PR) is generated.

Abstract: A valve, in particular a proportional pressure regulating valve, has a valve piston (12) longitudinally movable in a valve housing (10) for alternately releasing and connecting a user connection (A) to a pressure supply port (P) or a tank connection (T). The valve piston can be actuated by an actuating magnet (14) that produces a dither signal during operation. The valve piston (12) reaches a floating position within the valve housing (10) by a hydraulic lift limitation for the receipt of the dither signal.

Abstract: A pressure retaining valve (1) has a main control piston (39) guided longitudinally displaceably in a single-piece or multiple-piece valve housing (29) and a non-return piston (43). In a pressure retaining position, a fluid-conducting connection between connection points (37a, 37b, 21) is shut off by the two pistons (39, 43). Connection point (37a) serves to feed media. Connection point (37b) discharges media. Connection point (21) leads to a hydraulic consumer. In a load-raising position, the two pistons (43) move relative to one another into a release position, in which the connection between the medium feed (37a) and the consumer is established. In a load-reducing position, the two pistons (39, 43) assume a spacing from one another such that the connection between the medium discharge (37b) and the consumer is established. A monitoring device (75) determines the individual switching positions of the pistons (39, 43) to ensure reliable functioning of the pressure retaining valve (1).

Abstract: A valve device has a valve housing and a main piston (4) arranged in an axially slidable manner in a piston bore of the valve housing (2). A first consumer connection (A) and a second consumer connection (B) can be alternately connected to a pressure connection (P) and a tank connection (T1, T2) by the action of a first magnetic actuating system (6) and a second magnetic actuating system (8) with two pilot pistons (14, 16). In an actuated state of the respective pilot piston (14, 16), the main piston (4) follows the movement of the pilot piston (14, 16) due to the force ratio adjusting itself to actuate the fluid-carrying connection between the pilot chamber (10, 12) of the pilot piston (14,16) and the assignable tank connection (T1, T2) such that pilot oil flows.

Abstract: A compact unit has an electric motor accommodated in housing parts (7, 55) of a unit housing (45) and driving at least one hydraulic pump and giving off heat at the same time, an air heat-exchanging device, and a fan (19) drivable to produce an air flow. A flow-conducting device (47, 55) divides the air flow at least in a first partial flow flowing around the electric motor and a second partial flow flowing to the heat-exchanging device in the unit housing (45). Alternatively, arranged in series, the air flow first flows against the electric motor and then the heat-exchanging device, or that the incidence of the air flow occurs at least partially in the reverse direction.

Abstract: A pilot-controlled directional control valve, in particular a directional poppet valve, has a valve housing (10), at least three fluid connection points (12, 14, 16), a main control stage (18) and a pilot control stage. A further fluid-controlling intermediate stage (22) is arranged between the main control stage (18) and the pilot control stage (20). The main control stage (18) has a longitudinally movable main control piston (24). The pilot control stage has a longitudinally movable pilot control piston (26).

Abstract: A system for hydraulic systems includes a working cylinder (58) which operates as a consumer of hydraulic energy or as a generator of hydraulic energy. A hydraulic accumulator (1) can be charged by the working cylinder for storing energy and can be discharged for delivering energy to the working cylinder (58). One hydraulic accumulator is provided in the form of an adjustable hydropneumatic piston accumulator (1), in which with a plurality of pressure chambers (19, 21, 23, 25) adjoining effective surfaces (11, 13, 15, 17) of different sizes are on the fluid side of the accumulator piston (5). An adjusting arrangement (51) connects a selected pressure chamber (19, 21, 23, 25) or a plurality of selected pressure chambers (19, 21, 23, 25) of the piston accumulator (1) to the working cylinder (58) as a function of the pressure level that prevails respectively on the gas side of the piston accumulator (1) and on the working cylinder (58).

Abstract: A device, consisting of at least one control piston (12) which is longitudinally displaceable in a housing (10) comprising at least two connection points (P, A) for fluid, and which cooperates with a metering edge (34) of the housing (10) at a connection point (P), said point, in control positions of the control piston (12), supplying the other connection point (A) with fluid via a fluid connection, and which piston, as a result of occurring flow forces, tends to be drawn in the direction of a closing position which blocks one of these fluid connections.

Abstract: A pressure-limiting valve with feed function includes a valve housing (20) having a working connection (A) and a tank connection (T). A spring-loaded pressure-limiting valve piston (22) is mounted and longitudinally movable in the valve housing (20). A spring-loaded non-return valve piston (56) for the implementation of the feed function is designed as a hollow piston and is mounted to be longitudinally movable in the valve housing (20).

Abstract: A proportional pressure regulating valve has a valve piston (12) longitudinally movable in a valve housing (10) and connecting a utility connection (A) to a pressure supply connection (P) or to a tank or return flow connection (T) dependent on the displacement position of the valve piston. The valve piston is actuated by an actuation magnet (48) that can be supplied with current. A control device (50) is between the valve piston (12) and the actuation magnet (48), and allows the valve piston (12) to become pressureless on the valve piston side (52) facing the actuation magnet (48). The valve piston (12) is displaced in the direction of the actuation magnet (48) under the supply and/or utility connection pressure when the actuation magnet is not actuated.