Sauer-Danfoss Inc.

Danfoss Power Solutions Gmbh & Co Ohg

Danfoss Power Solutions (Zhejiang) Co. Ltd.

Carsten Fiebing

Reinhardt Thoms

Bernd Hames

Martin Wüstefeld

Heiko Laffrenzen

Zhimin Guo

Stanislav Smolka

Anja Fiebing

Niels Christophersen

Thoms Reinhardt

The present invention relates to an electronically controlled valve for a variable displacement pump, a hydraulic pump and a hydraulic pump system with switchable control functions. Multiple control functions of different types of hydraulic pumps can be implemented via one single electronically controlled valve combined with control elements and sensors. The hydraulic pump systems can be easily integrated into the overall application systems for intelligent control.

Electronically controlled valve, hydraulic pump, and hydraulic pump system

Hydraulic axial piston unit () of the swashplate construction type having a drive shaft () adapted to drive or be driven by a cylinder block (). The cylinder block comprises a plurality of cylinder bores (), in which several pistons () are moveable in general along the rotational axis () of the drive shaft () and relative to the cylinder bores (). First ends of the pistons () protrude outside of the cylinder bores () and are slidable fixed by means of slippers () to a swashplate (). The slippers () are hold down in a sliding manner on a sliding surface () of the swashplate () by means of a slipper hold down ring () arranged parallel to the sliding surface (). The slipper hold down ring () is in a sliding contact with its radial inner surface () with a matching surface () on a guide ball () rotationally fixed on the drive shaft () and axially moveable in direction of the rotational axis () relative to the cylinder block () against resilient forces of springs () characterized in that a mounting ring () is attached to the cylinder block () in order to limit the axial movement of the guide ball () towards the cylinder block ().

Hydraulic axial piston unit with central fixed hold down device

The invention relates to an axial piston engine with a filling pump integrated in a receiving bore of the axial piston engine, which filling pump comprises a gerotor set with an externally toothed inner ring and an internally toothed outer ring and also an inner thrust plate and an outer thrust plate. The two thrust plates enclose the gerotor set between them and, on their surfaces facing away from the gerotor set, are in each case supported via a pressure field seal, which surrounds the pressure field regions formed in the thrust plates, in such a way on the housing walls axially enclosing the filling pump that lateral play in the form of axial mobility of the filling pump is guaranteed.

Axial piston engine with integrated filling pump

A hydrostatic variable displacement unit is provided having a swash plate which serves to adjust the stroke of displacement pistons in a cylinder block and can be pivoted in its angular position by means of a servo system, the servo system having at least one servo piston with two servo-piston end surfaces which are in each case assigned a servo cylinder and a servo-piston rear surface, and the servo cylinders, by means of the assigned servo-piston end surfaces, in each case bounding a servo-cylinder pressure space. The servo piston is acted upon by a spring arrangement having at least one spring arranged outside the servo-cylinder pressure space and clamped between two spring plates. The two spring plates are acted upon by the springs in the direction of a stop of the particular servo cylinder that is situated on its side such that in the neutral position, the spring plates bear against the servo-piston rear surfaces and against the stop of the particular servo cylinder.

Hydrostatic variable displacement unit having a swash plate and a servo system having a spring arrangement

A hydrostatic adjustment unit with a swash plate for adjusting the stroke of displacer pistons which are arranged in a rotating cylinder block is described. The displacer pistons each have a slider block which bears against a support face of the swash plate and is held in abutment by means of a slider block holder. The slider block-holder has a number of bores for receiving the slider blocks corresponding to the number of displacers. The slider block holder at the same time forms the rotor of a rotational speed signal transmitter for determining the rotational speed of the cylinder block.

Hydrostatic adjustment unit with swashplate, rotating cylinder block and a rotational speed signal transmitter

An axial piston machine having a swashplate or an oblique axis which can be adjusted by means of servopistons and has a valve segment and an adjustment unit for the electrically proportional adjustment of the volumetric displacement. The adjustment unit comprises proportional magnets which can be activated electrically, and a control piston for controlling the oil pressure which moves the servopistons. The proportional magnets act on the control piston along a common tappet axis, a feedback device for feeding back the current swashplate or oblique-axis valve-segment position to the control piston being provided. The feedback device comprises spring levers' which can pivot about an axis, the spring levers&#x2032; each being mounted on the pivot axiswith a bearing shell, which are each composed of two component shells which support the spring lever&#x2032; at separate locations on the pivot axis, and which each essentially enclose a half-space about the pivot axis

Axial piston machine having a device for the electrically proportional adjustment of the volumetric displacement

In the stationary part () of an axial piston machine, a first flow duct () and second flow duct () intersect with the central axes () and (). A valve body () having a valve cone () and a tubular guide piston which can be displaced in relation to the valve cone is situated in the extension of the central axis () of the first flow duct (). The valve body () bears against a first valve seat () which is surrounded by an expanded section (). The entire valve body () moves in a tubular partial housing () which is connected to the stationary part () in a sealed manner via a seal (), a screw connection () and a flange () which rests on a shoulder () of the stationary part (). A first compression spring () and a second compression spring () serve to support the valve body () and its parts in relation to one another. An extension stem () passes through the tubular guide piston and guides the second compression spring (). The tubular partial housing () sits in a bore () of the stationary part (). Two valves Vand Vare formed, the valves setting flow paths between the first flow duct () and the second flow duct () which differ according to pressure ratios.

Valve arrangement for controlling hydraulic fluid in an axial piston machine

An axial piston machine having a swash plate or oblique axis which can be adjusted by means of servopistons and has a valve segment and an adjustment unit for the electrically proportional adjustment of the volumetric displacement, the adjustment unit comprising proportional magnets which can be activated electrically, and a control piston for controlling the oil pressure which moves the servopistons, the proportional magnets acting on this control piston along a common tappet axis. A feedback device for feeding back the current swash plate or oblique axis valve segment position is provided. The feedback device comprises spring levers and a pointer which can be pivoted about an axis, the pointer which is embodied as a two-armed lever engaging in the control piston on one side of the pivot axis, and between the spring levers on the other side.

Axial piston machine having a device for the electrically proportional adjustment of its volumetric displacement

A hydrostatic variable displacement pump has a swash plate ( ), which is used to adjust the stroke of displacement pistons in a cylinder block. The swash plate has its angle position pivoted in relation to the stroke direction of the displacement pistons by means of a servosystem. The servosystem is fitted on the housing ( ) of the variable displacement pump. The servosystem ( ) has a pressure cylinder ( ) and a servopiston ( ), which together form a servocylinder pressure chamber ( ). The servopiston ( ) operates in the pressure cylinder ( ), is subjected to compressive loading by means of a spring assembly ( ) and has a piston with at least two servopiston surfaces ( ) subjected to the action of pressure.

Hydrostatic variable displacement pump having springs arranged outside the servocylinder pressure chamber

A hydrostatic variable displacement pump of swash plate construction has a cylinder block , in a housing , with displacement pistons guided therein, a swash plate and at least a first bearing and a second bearing , which supports the angle adjustable swash plate . The housing has a first opening, through which the swash plate can be introduced. The first bearing has a removable outer race which is designed such that, following installation of the second bearing of the swash plate in the bearing seat , it fixes said swash plate in the bearing seat of the first bearing . The servomechanism is integrated in a cover which closes off the housing on the side of the first bearing

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Jevenstedt, Germany

Carsten Fiebing