Hydac Fluidtechnik Gmbh

Frank Schulz

Peter Bruck

Markus Bill

Philipp Hilzendegen

Frank Kattler

Christian Groh

Christian Stauch

Michael Reik

Olaf Pippel

Jan Lübbert

A pressure control device has at least two switching valves (), a feedback control unit (), a sensor unit (), and a voltage supply unit (), and continuously adjusts hydraulic systems.

Pressure control device

A device includes a regulating piston () guided longitudinally movably in a housing () and interacting with a control edge (), at a pressure supply port (P) that supplies a utility port (A) in regulating positions of the regulating piston () 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 () has a change of shape () from its general outer basic shape in the area of the control edge () of the housing () 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 (), which flow force pulls the regulating piston () into an open position opposite from the blocked position. The change of shape () also follows a step function, the function graph of which has at least one step more than the number of steps required to form the control edge ().

Device and valve for flow force compensation

A valve, in particular for use as a pressure compensator or maintenance-type component () in hydraulically actuated hoisting devices (), has a valve housing () with a control port (), a fluid inlet () and a fluid outlet (). A regulating piston () is longitudinally displaceably in the valve housing () and acts against an energy storage device () in the form of a compression spring, bringing the regulating piston () into positions forming a fluid-conveying connection between the fluid inlet () and the fluid outlet () or blocking this connection by a control pressure existing at the control port (). A first orifice () in the regulating piston () connects the control port () to a receiving space () for the energy storage device () in a fluid-conveying manner. A second orifice () is in an intermediate part () in the valve housing (). The receiving space () can be connected to a compensating chamber (), which connected to the fluid outlet () in a fluid-conveying manner ().

Pressure compensator valve

A control piston () is longitudinally displaceable in a housing () having two connection points (P, A) for fluid, and cooperates with a metering edge () of the housing () at a connection point (P). Point (P), in control positions of the control piston (), 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 () has, in the region of the control edge () of the housing (), a shape modification () of its cylindrical exterior basic form (), such that a flow contact surface () for fluid is created. The contact surface transfers a compensating force that acts against the flow force to the control piston () and that seeks to pull the control piston () into an opening position opposed to the closing position.

Device for flow force compensation

A hydraulic hybrid system for rotatory applications has an actuator () in the form of a motor pump unit (). The motor pump unit is coupled to a rotatory-operating device () and works as a consumer of hydraulic energy in one operating state of the device () and works as a producer of hydraulic energy in another operating state of the device (). A hydraulic accumulator () can be charged by the motor pump unit () for energy storage in the one operating state and can be discharged for energy release to the motor pump unit () in the other operating state. The hydraulic accumulator is an adjustable hydropneumatic piston accumulator () in which a plurality of pressure chambers () are delimited by active surfaces () of different sizes on the fluid side of the accumulator piston (). An adjusting arrangement () connects a selected pressure chamber () or a plurality of selected pressure chambers () of the piston accumulator () to the actuator () depending on the prevailing pressure level on the gas side of the piston accumulator () and at the actuator ().

Hydraulic hybrid system for rotatory applications

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

Valve device

A pilot-controlled directional control valve, in particular a directional poppet valve, has a valve housing (), at least three fluid connection points (), a main control stage () and a pilot control stage. A further fluid-controlling intermediate stage () is arranged between the main control stage () and the pilot control stage (). The main control stage () has a longitudinally movable main control piston (). The pilot control stage has a longitudinally movable pilot control piston ().

Pilot-operated directional control valve

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

System for improving the energy efficiency in hydraulic systems

A proportional pressure regulating valve has a valve piston () longitudinally movable in a valve housing () 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 () that can be supplied with current. A control device () is between the valve piston () and the actuation magnet (), and allows the valve piston () to become pressureless on the valve piston side () facing the actuation magnet (). The valve piston () is displaced in the direction of the actuation magnet () under the supply and/or utility connection pressure when the actuation magnet is not actuated.

A valve device, in particular a double stop-check valve, preferably of the two-way valve type, has at least three fluid connections () provided in a valve housing (). Two valve elements () can slide in the valve housing (). One control device () controls the valve elements (). At least one of the valve elements () forms, together with parts () of the valve housing (), a seat leak-tight closure part for the associated fluid connections ().

A valve, in particular for hydraulic circuits, includes a valve body () designed as a cartridge that can be fixed in a housing () having fluid connections () by a securing device (). The securing device has at least one blocking element () in the form of a separate component between the valve body () and the housing (). The blocking element has blocking surfaces that can be moved relative to the longitudinal axis () of the valve body () between an assembly position allowing the valve body () to be inserted into the housing () and a blocking position in which the blocking surfaces secure the valve body in an assembly position, preferably with zero backlash by bearing against retaining surfaces () of the housing () and the valve body ().

Valve

A directional poppet valve () has valve pistons (-) arranged in a valve housing () for controlling a plurality of fluid connections (A, B, P, T). The positions of each valve pistons (-) in the valve housing () can be changed by at least one actuating device. The fluid connections (A, B, P, T) are connected to one another or separated from one another alternately depending on the position of the valve pistons (-). The valve pistons (-) are arranged inline along at least one axis (R), consecutively and/or at least such as to partially interengage, in the valve housing ().

Directional poppet valve

A hydraulic system includes an actuator operating as a consumer of hydraulic energy and as a generator of hydraulic energy in different operating states, and includes a hydraulic accumulator (). In an operating state of the actuator (), the accumulator can be charged by the actuator for storing energy. In a different operating state, the accumulator can be discharged for delivering energy to the actuator (). The hydraulic accumulator is an adjustable hydropneumatic piston accumulator having a plurality of pressure chambers () adjoining effective surfaces () of different sizes on the fluid side of the accumulator piston (). An adjusting arrangement () connects a selected pressure chamber () or a plurality of selected pressure chambers () of the piston accumulator () to the actuator () as a function of the pressure level that prevails on the gas side of the piston accumulator () and on the actuator ().

System for improving the energy efficiency in hydraulic systems, piston accumulator and pressure accumulator provided for such a system

A valve (), in particular a pressure regulating valve or a pressure limiting valve for controlling a pressure of a medium () that flows through the valve (), includes a main stage () and a pilot stage () that actuates the main stage (). The main stage is actuated against the effect of a restoring device () by an energizable actuating device (). A pressure release stage () of the valve () has a surface area modification device ().

Valve, in particular a pressure regulating valve or pressure limiting valve

A proportional pressure-regulating valve () includes a valve housing () having pump, utility and tank connections (P, A, T). A regulating piston () is longitudinally displaceable within the valve housing () to selectively connect the pump connection (P) to the utility connection (A) and the utility connection (A) to the tank connection (T) and is controllable by a magnetic coil device (). The regulating piston () has a surface ratio () such that pressure on the utility connection (A) generates a counter force (F) against the magnetic force (F) of the magnetic coil device (), moving the regulating piston () back and causing reduction of pressure medium from the pump connection (P) to the utility connection (A) until the pressure acting on the utility connection (A) corresponds to the magnetic force (F) of the current signal applied to the magnetic coil device ().

Growing community of inventors

Blieskastel-Bierbach, Germany

Frank Schulz