Robert Boschgmbh

Walter Robeller

Gerhard Nonnenmacher

Dieter Bertsch

Volkmar Leutner

Hans-Jurgen Fricke

Karl Veil

Gunter Kersten

Paul Bosch

Berthold Pfuhl

Emil Knodel

Joachim Zumbraegel

Egon Tittmann

Heinz Walter

Michael Gaumnitz

Gerhard Nonnemacher

Roland Steimann

Adjustable hydrostatic pump with additional pressure change control unit

Electrohydraulic adjustable pump

Delivery flow and pressure controlling device for a hydrostatic pump

A positive-displacement machine includes a hollow housing provided with two diametrically opposed bores each having a first end communicating with an interior of the housing and a second end closed by a cover. A rotor member is adjustably displaceable in the interior of the housing due to displacement of two pistons positioned in the bores. The pistons are connected to a high pressure chamber, to thereby create in the pistons pressure sufficient to move the latter, to thereby move the rotor member. The housing is provided with control devices to change the pressure in the bores and create a pressure differential in the bores sufficient to move the rotor member into a predetermined position.

Positive-displacement machine

A control arrangement for a hydrostatic drive comprises a gear pump driven by an internal combustion engine and supplying fluid to a fluid motor. The control arrangement is constructed in such a manner that even at a high number of revolutions per time unit of the internal combustion engine, the fluid motor may be operated at a low number of revolutions.

Control arrangement for a hydrostatic drive

An arrangement for pumping fluids includes at least one variable-output pump and a drive therefor. An auxiliary pump is also driven by the drive and discharges control fluid at a rate corresponding to the speed of rotation of the drive into a discharge conduit in which a variable flow-through cross-sectional area throttle valve is located. The pressure in the discharge conduit upstream of the throttle valve controls the displacement of a control slide between the two end positions thereof in one of which the control slide controls the variable-output pump so as to increase the output thereof, while in the other of such positions of the control slide the pump is controlled so as to reduce the output thereof. The throttle valve is responsive to the pressure in the discharge conduit, but can be arrested in any position thereof when the drive is overloaded so that the flow-through cross-sectional area thereof is fixed, which results in a decrease of output of the variable-output pump when the drive is overloaded. Advantageously, the throttle valve is arrested when the power input to the drive exceeds a predetermined value. The arresting of the throttle valve may be effected by using an actuating electromagnet which is energized in response to overloading conditions of the drive by a switch interposed in the electric circuit of the electromagnet and controlled by the drive.

Pumping arrangement control device

The pump has a regulating element whose position is controlled by means of a first and second piston. The first piston is kept under pressure by the output pressure of the pump. The output side of the pump is also connected to a throttle valve which has a cross-section allowing fluid flow which varies as a function of pressure. The pressure difference created at the throttle valve output relative to the throttle valve input acts on a three-position three-port control valve which control the pressure on the second piston accordingly. The second piston has a larger diameter than the first piston.

Control system for a pump

In a piston machine of the type having a housing, a reciprocable piston in the housing and provided with an axial end portion and a piston-reciprocating element having a glide surface located opposite and movable with reference to the end portion for effecting the reciprocation of the piston, the invention provides for a glide shoe which is articulately connected to the end portion of the piston and which has a glide face in gliding contact with the glide surface of the piston-reciprocating element. The glide face has a recess which communicates via a passage with a source of pressure fluid, a sealing rim of substantially constant width surrounding the recess, and a plurality of face portions which are located outwardly of the sealing rim and configurated so that hydrodynamic pressure fields develop between the face portions and the respectively juxtaposed surface portions of the glide surface.

Piston machine construction

Growing community of inventors

Boblingen, Germany

Walter Robeller