Systems and methods for a hydraulic machine. The hydraulic machine includes, in one example, a rotational shaft, a central pin rotationally coupled to the rotational shaft and threadingly engaged with a cylinder block via a threaded interface, and pistons coupled to the rotational shaft and mated with cylinders in the cylinder block. The hydraulic machine further includes a distribution plate in fluidic communication with the cylinders and a fluid inlet and a fluid outlet.

A fluid pressure pump and a fluid pressure system in which leakage of fluid and ablation of a cylinder block and a port plate can be prevented by pressing the cylinder block to the port plate with an appropriate pressing force. A hydraulic pump includes a cylinder block that has a cylinder chamber that may be in communication with an oil passage of a port plate and in which a piston is housed; and a cylinder block pressing means imparting, to the cylinder block, a pressing force that presses the cylinder block to the port plate. The cylinder block pressing mechanism has a changing means that changes the force that presses the cylinder block to the port plate.

An axial variable displacement piston pump includes a drive shaft disposed on an axis, a piston barrel having a plurality of pistons disposed about and rotationally coupled to the drive shaft, a swash plate disposed about and rotationally coupled to the drive shaft, and a retention cage connected to the swash plate between the piston barrel and the swash plate. The swash plate and the piston barrel are configured to be simultaneously driven by the drive shaft and the swash plate is configured to tilt relative to the axis. The retention cage is configured to retain the plurality of pistons relative to the swash plate with rotation.

An axial variable displacement piston pump includes a drive shaft disposed on an axis, a piston barrel having a plurality of pistons disposed about and rotationally coupled to the drive shaft, a swash plate disposed about and rotationally coupled to the drive shaft, and a retention cage connected to the swash plate between the piston barrel and the swash plate. The swash plate and the piston barrel are configured to be simultaneously driven by the drive shaft and the swash plate is configured to tilt relative to the axis. The retention cage is configured to retain the plurality of pistons relative to the swash plate with rotation.

An integrated electro-hydraulic unit has a hydraulic machine, an electric machine encircling the hydraulic machine and a housing at least partially surrounding the electric machine and the hydraulic machine. The hydraulic machine includes a rotary working group configured to pump a fluid. The electric machine includes a stator and a rotor coupled to the rotary working group such that the rotor drives the rotary working group. The housing includes a front cap and an end cap each having a plurality of tie rod openings. The housing includes a plurality of tie rods and a housing shell encircling the electric machine and positioned between the front and end caps. The tie rods extend through the openings in the front cap and end cap. Nuts are tightened on the tie rods such that the front cap, the end cap, and the housing shell are compressed via tension in the tie rods.

An integrated electro-hydraulic unit has a hydraulic machine, an electric machine encircling the hydraulic machine and a housing at least partially surrounding the electric machine and the hydraulic machine. The hydraulic machine includes a rotary working group configured to pump a fluid. The electric machine includes a stator and a rotor coupled to the rotary working group such that the rotor drives the rotary working group. The housing includes a front cap and an end cap each having a plurality of tie rod openings. The housing includes a plurality of tie rods and a housing shell encircling the electric machine and positioned between the front and end caps. The tie rods extend through the openings in the front cap and end cap. Nuts are tightened on the tie rods such that the front cap, the end cap, and the housing shell are compressed via tension in the tie rods.

A hydrostatic axial piston machine is disclosed, in the housing of which a drive shaft is rotatably mounted about an axis of rotation. The housing comprises a pot-like housing part having a first abutment and a cover-like housing part having a second abutment. The two abutments are clamped against one another in a sealing manner. A first fitting pin is inserted precisely into a first fitting recess of the first abutment on the one hand and into a second fitting recess of the second abutment on the other hand. A second fitting pin is provided on a side opposite the axis of rotation, which is inserted precisely into a third fitting recess of the first abutment on the one hand and into a fourth fitting recess of the second abutment on the other hand. The second fitting recess has a radial widening relative to the axis of rotation, whereby the second fitting recess is a slotted hole and/or a fitting groove.

A hydrostatic axial piston machine is disclosed, in the housing of which a drive shaft is rotatably mounted about an axis of rotation. The housing comprises a pot-like housing part having a first abutment and a cover-like housing part having a second abutment. The two abutments are clamped against one another in a sealing manner. A first fitting pin is inserted precisely into a first fitting recess of the first abutment on the one hand and into a second fitting recess of the second abutment on the other hand. A second fitting pin is provided on a side opposite the axis of rotation, which is inserted precisely into a third fitting recess of the first abutment on the one hand and into a fourth fitting recess of the second abutment on the other hand. The second fitting recess has a radial widening relative to the axis of rotation, whereby the second fitting recess is a slotted hole and/or a fitting groove.