Abstract: The invention relates to a hydrostatic displacer unit with a pivoting mechanism for two conveying directions for the continuous variation of the stroke of displacement pistons and with a servo system by means of which the pivoting mechanism can be moved in opposite pivoting directions. The servo system comprises at least two servocylinders, by means of which servopjstons which actuate the pivoting mechanism can be moved, and an adjusting device in each case with a pressure-reducing valve for each servocylinder. The control pistons of the pressure-reducing valves are coupled mechanically along a common axis of movement by means of a spring arrangement.

Abstract: Arranged in a hydraulic circuit is a valve with an L-shaped duct arrangement, which is formed by a transverse duct 2 and a longitudinal duct 3. Formed in extension of the longitudinal duct 3 is a holding and guiding bore 4, in which a throttling element, comprising a throttle slide 10 and a valve piston 21 that can be displaced therein, can be displaced longitudinally. The valve piston 21 has a passage hole 25, which is connected to the interior of the throttling element and two proportionate annular chambers 17a and 17b. Of these, the proportionate annular chamber 17b is connected to a pilot control valve via a control duct 19. Depending on the direction and pressure of the hydraulic fluid flowing through the L-shaped duct arrangement, the throttling element is moved in or out and extended or compressed in the process.

Abstract: In the housing 1 of a hydraulic machine, the pressure Pi acts in the chamber 2. For this purpose, a passage opening 4 is provided, which is formed as a valve seat 5. A valve body 6 can be displaced longitudinally in the housing 1 and forms a pressure-tight spring chamber for an inner valve spring 21. The spring chamber is connected to the chamber 2 via a pressure equalizing hole 9. The prestress of the inner valve spring 21 can be set by means of a setting screw 18. In addition, there is an outer valve spring 22. Both the valve springs load the valve body 6 with the effect of closing it. The pressure equalizing valve described combines a compact design with an advantageous flow characteristic. When a maximum value of p1 is reached, the valve body 6 lifts off the valve seat 5 and hydraulic fluid from the chamber 2 flows away via the valve chamber 3.

Abstract: An arrangement for filtering a hydraulic fluid having a bypass line connecting the feed channel to the discharge channel where the bypass line is opened by a pressure switching valve when a pressure change is caused by the contamination of the filter element.

Abstract: 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.

Abstract: In the stationary part (1) of an axial piston machine, a first flow duct (2) and second flow duct (5) intersect with the central axes (3) and (6). A valve body (20) having a valve cone (21) and a tubular guide piston which can be displaced in relation to the valve cone is situated in the extension of the central axis (3) of the first flow duct (2). The valve body (21) bears against a first valve seat (4) which is surrounded by an expanded section (7). The entire valve body (20) moves in a tubular partial housing (9) which is connected to the stationary part (1) in a sealed manner via a seal (11), a screw connection (10) and a flange (12) which rests on a shoulder (13) of the stationary part (1). A first compression spring (27) and a second compression spring (28) serve to support the valve body (20) and its parts in relation to one another. An extension stem (22) passes through the tubular guide piston and guides the second compression spring (28).

Abstract: A hydrostatic variable displacement pump has a swash plate (3), 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 (6) of the variable displacement pump. The servosystem (4) has a pressure cylinder (18) and a servopiston (7), which together form a servocylinder pressure chamber (8). The servopiston (7) operates in the pressure cylinder (18), is subjected to compressive loading by means of a spring assembly (9,10) and has a piston with at least two servopiston surfaces (11, 12) subjected to the action of pressure.

Abstract: A hydrostatic variable displacement pump of swash plate construction has a cylinder block 2, in a housing 1, with displacement pistons 3 guided therein, a swash plate 4 and at least a first bearing 5 and a second bearing 6, which supports the angle adjustable swash plate 4. The housing 1 has a first opening, through which the swash plate can be introduced. The first bearing 5 has a removable outer race 13 which is designed such that, following installation of the second bearing 6 of the swash plate 4 in the bearing seat 8, it fixes said swash plate in the bearing seat 7 of the first bearing 5. The servomechanism 9, 10 is integrated in a cover 10 which closes off the housing 1 on the side of the first bearing 5.

Abstract: The invention provides an axially compact gear pump comprising a housing (13) and end plate (14). Dowels (18) extend from the housing through the end plate to locate the end plate (14) relative to the housing (13), and project from the end plate (14) for locating the assembled gear pump (10) on its drive means in use. Assembly bolts (20) extend through the housing (13) and into the end plate (14) to hold the gear pump together for transportation prior to use, but mounting bolts (22) for mounting the gear pump on the drive means or on a test plate in use pass completely through both the housing (13) and end plate (14), providing enhanced rigidity to the assembly.

Abstract: A hydrostatic variable displacement pump has a swash plate (3), 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 (6) of the variable displacement pump. The servosystem (4) has a pressure cylinder (18) and a servopiston (7), which together form a servocylinder pressure chamber (8). The servopiston (7) operates in the pressure cylinder (18), is subjected to compressive loading by means of a spring assembly (9,10) and has a piston with at least two servopiston surfaces (11, 12) subjected to the action of pressure.

Abstract: A hydrostatic variable displacement pump of swash plate construction has a cylinder block 2, in a housing 1, with displacement pistons 3 guided therein, a swash plate 4 and at least a first bearing 5 and a second bearing 6, which supports the angle adjustable swash plate 4. The housing 1 has a first opening, through which the swash plate can be introduced. The first bearing 5 has a removable outer race 13 which is designed such that, following installation of the second bearing 6 of the swash plate 4 in the bearing seat 8, it fixes said swash plate in the bearing seat 7 of the first bearing 5. The servomechanism 9, 10 is integrated in a cover 10 which closes off the housing 1 on the side of the first bearing 5.