An inclined-axis axial piston machine includes a housing, a drive shaft and a cylinder barrel. The drive shaft is mounted in the housing so as to be rotatable with respect to a first axis of rotation and is integral with a flange. Each piston is coupled to the flange via a ball joint. A multiplicity of counting perforations are arranged in a periodically distributed and continuous manner over an outer circumferential surface of the flange. The housing accommodates a sensor arranged opposite the counting perforations such that rotation of the drive shaft causes a signal change at the sensor. Each counting perforation is formed integrally from the flange, in the form of a recess having a single continuous perimeter. A side wall of the recess, starting from the perimeter, extends uninterruptedly, without sharp bends or offsets, over the entire circumference of the perimeter.

The invention relates to a port plate 10, 11 that is used as a valve plate or a bearing plate. The port plate 10, 11 comprises a fluid blocking surface section 15 and a fluid passage surface section 13, 14 that is arranged within said at least one fluid blocking surface section 15. Structural reinforcement elements 12, 19 are arranged within the fluid passage orifice of the fluid passage surface section 13, 14.

A gear shaft assembly for a hydraulic unit is disclosed which includes a gear shaft including a main body portion having a central axis, an outer periphery, an inner periphery and a medial region extending between the outer periphery and the inner periphery, the inner periphery including an annular bearing surface that circumscribes a cylindrical cavity dimensioned to accommodate a roller bearing assembly, and an elongated axial shaft portion extending distally from the main body portion, and a roller bearing assembly arranged within the cylindrical cavity of the main body portion of the gear shaft and including a plurality of circumferentially arranged roller bearing elements in rolling contact with the annular bearing surface.

The hydraulic piston forms a hydraulic chamber with a cylinder and has a cylindrical body which receives a seal and whose external cylindrical surface is housed with little clearance in the cylinder in such a manner as to leave an interstitial space, the cylindrical body being run through by a cooling and lubrication pipe which can be opened or closed by a cooling and lubrication valve which is moved by translation by a valve-actuator in such a manner that fluid can pass via a flow calibration opening from the hydraulic chamber to the interstitial space when the pressure existing in the hydraulic chamber is low and cannot pass when the pressure in the chamber is high.

The hydraulic piston forms a hydraulic chamber with a cylinder and has a cylindrical body which receives a seal and whose external cylindrical surface is housed with little clearance in the cylinder in such a manner as to leave an interstitial space, the cylindrical body being run through by a cooling and lubrication pipe which can be opened or closed by a cooling and lubrication valve which is moved by translation by a valve-actuator in such a manner that fluid can pass via a flow calibration opening from the hydraulic chamber to the interstitial space when the pressure existing in the hydraulic chamber is low and cannot pass when the pressure in the chamber is high.

A hydrostatic positive displacement machine has an adjustable swept volume, and has a lifting element, a rotor with positive displacement elements supported on the lifting element, and a hydraulic adjusting device that adjusts the swept volume and includes an adjusting piston that is mounted in or on a cylinder, is movable axially rectilinearly in relation to the cylinder, and is adjacent to a pressurizable adjusting chamber. A bearing gap is formed between a circular-cylindrical bearing surface of the adjusting piston and a circular-cylindrical bearing surface of the cylinder. The adjusting piston is mounted hydrostatically, wherein at least three pressure pockets are distributed uniformly in a row over the circumference of a bearing surface. Pressure fluid flows into each pressure pocket via a fixed throttle, which is assigned only to the respective pressure pocket, and flows out of each pressure pocket via the bearing gap.

A hydraulic device (1) comprises a housing (27), a shaft (2) which is mounted in the housing (27) and rotatable about a first axis of rotation (4), wherein the shaft (2) has a flange (8) extending perpendicularly to the first axis (4), a plurality of pistons (9) which are fixed to the flange (8) at equiangular distance about the first axis of rotation (4), and a plurality of cylindrical sleeves (10) cooperating with the pistons (9) to form respective compression chambers (11) of variable volume. The sleeves (10) are rotatable about a second axis of rotation which intersects the first axis of rotation (4) by an acute angle such that upon rotating the shaft (2) the volumes of the compression chambers (11) change. Each piston (9) has a piston head (14) including a ball-shaped circumferential outer side. Each of the pistons (9) has a modular structure comprising a piston head member (14) which forms the piston head, a piston pin (20) which is fixed to the flange (8) and to which the piston head member (14) is mounted, and a spacer (26) which is located at the outer side of the piston pin (20) and sandwiched between the piston head member (14) and the flange (8).

A hydrostatic axial piston machine has a housing. In the housing of the hydrostatic axial piston machine, an actuating pressure cylinder is formed at an angle to the drive shaft. A control valve is inserted into the actuating pressure cylinder in a cartridge type of design. In order to enable maximum movement of an actuating piston in the direction toward the control valve, the cartridge is of shortened design. To this end, an actuating pressure port, which is arranged between a high-pressure port and a low-pressure port, and an actuating pressure passage are arranged completely inside the cartridge.

An articulated coupling is provided for a piston sealing device for a piston which includes a fixed skirt and a sliding skirt interconnected by a mechanical inter-skirt connection for axially compressing a continuous extensible segment under the action of a sliding skirt spring, the coupling replacing, on the one hand, the fixed skirt by a ball-joint skirt and providing, on the other hand, a troncospherical piston end which cooperates with a skirt troncospherical bearing surface provided on the ball joint skirt while an articulation unit interposed between the inter-skirt mechanical connection and the piston and/or between the connection and the sliding skirt.

One object is to provide a hydraulic pump that allows a drive source to be started with a small torque. The hydraulic pump includes: a cylinder block having a plurality of cylinder bores and disposed so as to be rotatable; pistons each retained in associated one of the cylinder bores so as to be movable; a swash plate for controlling the amount of movement of the pistons in accordance with the size of the tilt angle; a first pressing unit for pressing the swash plate in such a direction as to reduce the tilt angle of the swash plate; and a second pressing unit for pressing the swash plate in such a direction as to increase the tilt angle of the swash plate by the pressure supplied from the outside.