Linde Hydraulics Gmbh & Co. Kg

Burkhard Stuermer

Horst Tobias

A hydrostatic drive system includes a differential cylinder connected in a closed circuit to a high-pressure pump. A piston-side compression chamber and a piston-rod-side compression chamber of the differential cylinder are in communication with the high-pressure pump. The closed circuit includes a protection device having first and second protection valve devices that each includes a pressure relief valve and an anti-cavitation valve. The pressure relief valve of the first protection valve device is provided with an override device, by means of which the opening pressure of the pressure relief valve can be varied. When the high-pressure pump delivers into the piston-rod-side compression chamber, the pressure relief valve of the first protection valve device is adjusted by means of the override device to a reduced opening pressure and the differential volumetric flow flows out via the pressure relief valve to a low-pressure system.

Hydrostatic drive system

A hydrostatic positive displacement machine () is operated in a closed circuit and delivers hydraulic fluid into a working circuit. The displacement volume is varied by a control device () having a variable displacement piston device (). The machine () has a swivel-back device () which, in the event of a decrease of the feed pressure from the feed pressure source (), guarantees actuation of the machine () toward a reduction of the displacement volume. The swivel-back device () includes at least one pressure sequence valve (), which is in communication on the input side with the working circuit of the machine (). In the event of a decrease in the feed pressure from the feed pressure source () below a limit pressure, the pressure sequence valve () makes it possible to supply the control device () of the machine () with hydraulic fluid from the working circuit.

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Kleinostheim, Germany

Burkhard Stuermer