A hydrostatic axial piston machine includes a cylinder drum having a substantially hollow cylindrical base body, and liners. The body includes cylinder bores located around a central axis. The liners have an outer diameter press-fitted into the bores such that an outer end face of each liner is positioned in a region of an opening of a respective bore, and such that an inner end face of each liner is positioned deep within the respective bore. An outer half of each liner, starting from the outer end face, includes an axially delimited circumferential recess in an outer casing surface of the liner. The machine is configured to operate with great forces acting between the liners and displacement pistons. The recess in each liner is shaped such that, in an axial section through the liner enclosing an axis of the liner, a depth of the recess increases more than once and decreases more than once.

A hydrostatic positive-displacement machine, in particular a hydrostatic axial piston machine, having a cylinder drum with at least one cylinder, in which a longitudinally displaceable piston is received, which is supported directly or indirectly by a support portion on an inclined plane of the positive-displacement machine. An outer circumferential surface portion of the piston is in bearing contact with an inner circumferential surface portion of the cylinder.

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 cylinder block for use in an integrated drive generator has a shaft portion with a relatively small outer diameter and a cylindrical body portion having a larger outer diameter than the shaft portion, and said cylindrical body portion formed with a plurality of piston chambers, said cylindrical body portion extending from a first end to a second end, said second end being provided with cylindrical ports leading into said piston chambers and said cylindrical ports having a third end and a fourth end wherein a ratio of a first distance from said first end to said fourth end to a second distance from said first end to said second end being between 0.91 and 0.93. A generator and a method are also described.

A hydrostatic axial piston pump of swashplate construction, which is also configured to be operated as a motor, has a stationary control plate against which a rotating cylinder drum is tensioned. During operation, a tilting tendency of the cylinder drum arises in the direction of that quadrant of the control plate which is operatively connected to the first part of the displacement stroke of the pistons. The control plate has a supporting device configured for the cylinder drum. The supporting device is arranged adjacent to an outer edge of the control plate in the first quadrant thereof. The supporting device is configured to be formed by a hydrostatically relieved additional field.

A hydrostatic axial piston machine includes a cylinder drum having a substantially hollow cylindrical base body, and liners. The body includes cylinder bores located around a central axis. The liners have an outer diameter press-fitted into the bores such that an outer end face of each liner is positioned in a region of an opening of a respective bore, and such that an inner end face of each liner is positioned deep within the respective bore. An outer half of each liner, starting from the outer end face, includes an axially delimited circumferential recess in an outer casing surface of the liner. The machine is configured to operate with great forces acting between the liners and displacement pistons. The recess in each liner is shaped such that, in an axial section through the liner enclosing an axis of the liner, a depth of the recess increases more than once and decreases more than once.

A hydrostatic axial piston machine includes a housing, a cylinder barrel, and a drive shaft, which are connected together and mounted in the housing so as to rotate jointly about a first axis. The machine also includes a swash plate mounted in the housing so as to pivot about a second axis to adjust a swept volume of the machine. The machine further includes a hydraulic actuating apparatus, which has an actuating piston that delimits an actuating chamber. The machine also includes a regulating valve attached to a flange face of the housing. The regulating valve has connections situated in the flange face that are used to communicate hydraulic fluid to and from the actuating chamber. The flange face is arranged obliquely so as to enclose an angle with the second axis that is greater than 0 and smaller than 90.

A hydraulic machine comprising: an outer casing comprising a first front plate and a second front plate, a shaft rotatable about a main axis, a first rotor comprising a first rotor body rotatable with said shaft around said main axis, and a plurality of first pistons with respective spherical ring heads fixed to said first rotor body, a second rotor comprising a second rotor body and a plurality of second pistons with respective spherical ring heads, wherein the second rotor is rotatable about a secondary axis, inclined with respect to said main axis, a plurality of sleeves that are separate and independent from each other, each having a cylinder open at opposite ends and engaged on opposite sides by a first piston and by a second piston.

A cylinder block includes: a plurality of cylinder bores including respective openings formed on a piston insertion end surface of the cylinder block, pistons being inserted in the respective cylinder bores and being configured to reciprocate and slide in the respective cylinder bores when the cylinder block rotates; and a cooling portion, wherein the cooling portion includes a plurality of cooling holes each formed between the adjacent cylinder bores and extending from the piston insertion end surface in an axial direction of the cylinder block.

A hydraulic pump/motor includes: a cylinder block rotating about a rotation axis; a piston in a cylinder bore; and a valve plate facing a cylinder port. The valve plate includes: a high pressure port through which oil discharged from the cylinder port flows; a low pressure port through which the oil to be sucked into the cylinder port flows; a region disposed between the high and low pressure ports in a circumferential direction of the rotation axis and including a top dead center position facing the cylinder port of the cylinder bore in which the piston moved to a top dead center is disposed; and a residual pressure release port between the top dead center position and the low pressure port in the region. The residual pressure release port includes first and second ports disposed at positions different from each other in the radial direction of the rotation axis.