Mannesmann Rexroth Corporation

Mannesmann Rexroth Ag

Rainer Knoll

Gunter Fischer

Horst Fischer

Positioning drive, in particular for a machine tool

Closed loop control circuit for a variable hydraulic pump the output flow of the pump being variable by control means and the pump including at least two closed loop controllers actuating the control means, wherein at least one hydraulic switching element is provided which automatically connects to the control means the closed loop controller providing the highest or the lowest pressure.

Closed loop control circuit for variable hydraulic pump

A vane pump or a vane motor is here specified, having a variable displacement volume. The vane pump has a vane rotor and an annular stator that surrounds the rotor eccentrically and that is stabilized by means of a piston arrangement for adjusting the eccentricity that determines the displacement volume. The piston arrangement includes at least one pendulum piston that is acted upon by a pressure medium, the pendulum piston being guided in a sealed manner in a housing bore by a piston head that delimits a control space. To simplify the assembly and to decrease manufacturing costs while simultaneously improving the sealing action and increasing the peripheral life of the guide surfaces, plastic rings, which are composed of wear resistant, sliding material, or are prestressed radially, to guide the piston in the piston bore and to seal the control space are embedded, inserted or emplaced in the piston head.

Vane pump

A hydraulic circuit comprising a control pump having first and second adjustment means for changing the output volume of fluid pump, and a regulating valve adapted to suppy user means with a pressurized liquid.

Regulating valve for a hydraulically adjustable control pump

The invention relates to a radial piston machine comprising height adjustment means, control means and adjustment means all having abutment means designed such that the cam ring of the machine will carry out during its adjustment a substantially rolling movement.

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Burgsinn, Germany

Rainer Knoll