A hydraulic pump having a rotary shaft rotatably supported with respect to a casing, the hydraulic pump including: a bearing part provided to one end side and the other end side of the rotary shaft; and a first annular member provided around the rotary shaft on at least one side of the one end side and the other end side of the rotary shaft. The bearing part on the one side has a support part which rotatably supports the rotary shaft, and a preload applying member which applies a preload in the axial direction to the support part. The first annular member is interposed between the bearing part of the one side and a receiving part of the rotary shaft in the axial direction, and an inner diameter of the first annular member is larger than a diameter of the rotary shaft.

A hydrostatic axial piston machine includes a housing and a pivot cradle. At least one slide bearing of the pivot cradle on a high-pressure side is hydrostatically relieved. The slide bearing includes one or two pairs of relief grooves. A relief pressure field develops about and between the one or two pairs of relief grooves as the grooves are supplied with relief pressure medium on one side and are closed at their outer ends. An optional slide bearing on a low-pressure side has one or two limiting grooves which delimit the relief pressure field there, as the limiting grooves are open at their outer ends.

A variable displacement axial pump, including: a housing including first and second inlet ports and first and second outlet ports; a shaft arranged to receive rotational torque; an axis of rotation for the shaft; swash plate located in the housing; a first cylinder block located in the housing and including first and second through-bores and first and second pistons at least partly disposed in the first and second through-bores, respectively, and connected to the swash plate; and a second cylinder block located in the housing and including third and fourth through-bores and third and fourth pistons at least partly disposed in the third and fourth through-bores, respectively, and connected to the swash plate. The shaft is arranged to rotate, with respect to the swash plate, the first and second cylinder blocks about the axis of rotation.

Provided is a variable displacement pump which sucks and discharges a working fluid by moving a piston with a stroke in response to an inclination angle of a swash plate, the variable displacement pump including: a control piston which includes a columnar piston portion pressing the swash plate and adjusts the inclination angle of the swash plate between a maximal inclination angle in which a discharge capacity of the working fluid becomes maximal and a minimal inclination angle in which the discharge capacity of the working fluid becomes minimal; a piston accommodation portion which is formed in the housing and accommodates the piston portion; and a pressed portion which is disposed between the swash plate and the piston portion and is pressed toward the swash plate by the piston portion, in which when the inclination angle of the swash plate is an intermediate inclination angle in which the discharge capacity of the working fluid becomes an intermediate amount between the maximal amount and the minimal amount, a contact point between the piston portion and the pressed portion is located at a center portion including an axis center of the piston portion in an end surface on the side of the swash plate in the piston portion.

A rolling bearing includes rollers clamped between an inner raceway and an outer bearing shell. The outer bearing shell bears with its outer circumferential surface against an outer component which can be a housing of an axial piston machine. The inner raceway is either formed directly on an inner component, or it is formed on an inner bearing shell, which bears against the inner component. In order to permit tilting of the inner component, wherein the rollers remain in predetermined contact with the two raceways, at least one beveled contact region or a region reduced in another way is provided on the outer circumferential surface of the outer bearing shell.

A hydraulic pump having a rotary shaft rotatably supported with respect to a casing, the hydraulic pump including: a bearing part provided to one end side and the other end side of the rotary shaft; and a first annular member provided around the rotary shaft on at least one side of the one end side and the other end side of the rotary shaft. The bearing part on the one side has a support part which rotatably supports the rotary shaft, and a preload applying member which applies a preload in the axial direction to the support part. The first annular member is interposed between the bearing part of the one side and a receiving part of the rotary shaft in the axial direction, and an inner diameter of the first annular member is larger than a diameter of the rotary shaft.

A hydrostatic axial piston machine (1) has a housing (2), a rotatable drive shaft (4) mounted in the housing (2) by a bearing device (5) that comprises at least one roller bearing (5a; 5b), a cylinder drum (7) having at least one piston bore (8), and a longitudinally displaceable piston (10) in each piston bore. A spray jet lubrication system (50) for the roller bearing (5a; 5b) includes at least one lubricant spray jet (51a; 51b) directed toward the area of an axial edge (30; 32) of an inner ring (5c; 5d) of the roller bearing (5a, 5b) with which the roller bodies of the roller bearing (5a, 5b) are in contact via an end surface.

An example pump includes: (i) a swash block having (a) a first trunnion arm, (b) a second trunnion arm, and (c) a first curved support surface and a second curved support surface disposed on an exterior surface of the swash block; and (ii) a housing comprising (a) a first bore, (b) a second bore, and (c) an internal chamber having a first curved bushing and a second curved bushing, where the swash block is supported within the internal chamber of the housing by the first trunnion arm being positioned in the first bore of the housing, the second trunnion arm being positioned in the second bore of the housing, the first curved support surface being positioned against the first curved bushing of the housing, and the second curved support surface being positioned against the second curved bushing of the housing.

The present disclosure relates to a coupling assembly for a variable displacement hydraulic unit. The coupling assembly may have a rotatable swashplate, a swashplate bearing including a cage and a plurality of rollers mounted on the cage, a pin fixed to the swashplate, and a coupling member rotatably supported on the pin. The coupling member is configured to contact a portion of the cage to move the swashplate bearing upon rotation of the swashplate.

The present disclosure relates to a coupling assembly for a variable displacement hydraulic unit. The coupling assembly may have a rotatable swashplate, a swashplate bearing including a cage and a plurality of rollers mounted on the cage, a pin fixed to the swashplate, and a coupling member rotatably supported on the pin. The coupling member is configured to contact a portion of the cage to move the swashplate bearing upon rotation of the swashplate.