Displacement control device for variably adjusting the displacement of an axial piston hydraulic pump including a rotary shaft rotatable around a shaft axis. A torque can be applied for rotating the rotary shaft to open and close servo pressure lines to adjust the displacement volume of the axial piston hydraulic pump. Concentric to the shaft axis in a mid-portion of the rotary shaft a detent sleeve is positioned having an abutment area onto which, in the neutral position, a sliding element abuts. The detent sleeve, in operating conditions is rotatably fixed with the rotary shaft and turns with the rotary shaft and for neutral position adjustments in non-operating conditions, the detent sleeve and the rotary shaft are detachable from each other such that the rotary shaft can be turned relative and independently within the detent sleeve, which is held in its neutral position by the sliding element.

An axial piston machine has a swash plate and an adjusting device having an adjusting cylinder and a double-acting adjusting piston which is longitudinally movable in the adjusting cylinder and includes a piston and a piston rod, which is fixedly connected to the piston and is articulated to the swash plate. The joint between the adjusting piston and the swash plate is a movable swivel joint having a joint body receptacle on one part and a joint body on the other part of the adjusting piston and the swash plate. The joint body is closely guided in the joint body receptacle in the direction of movement of the adjusting piston, is to rotatable about an axis of rotation running parallel to the pivot axis of the swashplate, and is movable with a directional component perpendicular to the direction of movement of the adjusting piston and perpendicular to the axis of rotation.

An actuating piston for a hydrostatic adjustment installation includes at least one sealing and guiding unit which is insertable into a circumferential recess of an actuating piston. The circumferential recess is composed of two regions, and has the effect of improving the guiding and sealing of the actuating piston. The actuating piston is arranged in an adjustment installation.

An actuating cylinder for an adjustment apparatus of a pivot angle of a hydrostatic axial piston machine has a hydraulic stop which connects an actuating pressure chamber of the actuating cylinder to an interior of the housing of the axial piston machine if the actuating piston is maximally extended. To this end, a channel is provided on the actuating piston side, while a control edge is provided on the housing side. The control edge is formed at the interface of a stop bore with the actuating cylinder bore. The stop bore may also be a leakage bore of the axial piston machine.

Hydraulic axial piston unit having a rotational group for driving or being driven by a driving shaft, and a tiltable displacement element for adjusting the displacement volume of the rotational group. The rotational group includes a rotatable cylinder block in which working pistons are mounted reciprocally moveable in cylinder bores for conveying hydraulic fluid from a kidney-shaped inlet port to a kidney-shaped outlet port on a valve segment. At least two control ports are located on the valve segment each between the respective circumferential ends of the kidney-shaped inlet port and the outlet port. The control ports can be brought sequentially in fluid connection with the cylinder bores when the cylinder block is rotating. At least one hydraulic fluid injector is connected fluidly to one control port, for sequentially injecting pressurized hydraulic fluid via the control port into the passing cylinder bores. Via the other control port hydraulic fluid can be drained from passing cylinder bores.

1. Swash plate-type axial piston pump. 2. A swash plate-type axial piston pump, in particular for hydraulic systems, having a cylinder drum (3), which can be driven in rotation about an axis of rotation (7) in a pump housing (1) and in which pistons (9) are arranged axially movable, the actuating ends of which are accessible from outside of the cylinder drum (3) and are supported at least indirectly on a swash plate (15), which, in order to set the stroke of the pistons (9) and thus the fluid system pressure generated by these, can be swiveled to the desired angle of inclination relative to the axis of rotation (7) by means of an adjustment device (21), which has at least one swiveling lever (23), which can be deflected and returned in at least one direction by means of an actuator and which has in at least one hydraulically actuated actuating cylinder (31, 43) one actuating piston (35) each, which acts on one end on an articulation point (29) of the swivel lever (23), is characterized in that the at least one actuating piston (35, 47) has at its end, facing away from the articulation point (29), a guide surface (73), which is an integral part of the actuating piston (35, 47) and is in contact with an assigned guide surface (33, 45) of the actuating cylinder (31, 43) and in that at least one compensation means (75, 70, 59) is present, which orients the guide surfaces (73; 33, 45) in their respective positions relative to each other. 3. FIG. 5.

A hydraulic motor apparatus includes a motor housing engaged to an end cap having a first porting system and an adapter connected to an external surface of the end cap and having a second porting system. A filter may be attached to the adapter and connected to the second porting system and a pressure reducing valve in the adapter is connected to the second porting system. The assembly may also include a controller operatively connected to the pressure reducing valve and system sensors measuring parameters affected by the output of the hydraulic motor apparatus, whereby the pressure reducing valve is operatively controlled by the controller in response to input from the system sensors.

An actuating piston for a hydrostatic adjustment installation includes at least one sealing and guiding unit which is insertable into a circumferential recess of an actuating piston. The circumferential recess is composed of two regions, and has the effect of improving the guiding and sealing of the actuating piston. The actuating piston is arranged in an adjustment installation.

A hydrostatic piston engine comprises a housing with a cylinder drum with cylinder bores mounted rotatably therein. Each of the cylinder bores receives a working piston in a longitudinally displaceable manner, via which a hydrostatic working chamber is delimited by the cylinder bore. The hydrostatic working chamber has an opening on an outer surface of the cylinder drum by which, when the cylinder drum rotates, outlets of a high-pressure chamber and of a low-pressure chamber of the piston engine and a reversing surface arranged between the two outlets in the rotational direction can be passed over in alternating fashion. At least one pressurizing medium channel is provided which, on one hand, opens out in the reversing surface and, on the other, into a pressurizing medium trough of the piston engine.

A hydrostatic axial piston machine includes a housing, a connection plate closing the housing, working connections formed on the connection plate, a drive shaft, a swashplate, a cylinder drum coupled to the shaft in the direction of rotation, bores formed in the drum and each including a piston, a control plate against which the drum bears, a retraction plate for removing a piston from the bores, and a retraction ball arranged in front of the first end face of the drum which surrounds a drum neck of the drum and the shaft and by which the retraction plate is loaded in the direction of the swashplate. A pressure chamber is defined by seals between the retraction ball, the drum, and the shaft, and is configured to be acted upon by a pressure above a housing pressure. The retraction ball is sealed against the drum neck and against the shaft.