A hydrostatic piston machine unit, which is in particular designed as a hydrostatic axial piston machine unit, comprises at least two driving mechanisms that can be driven synchronously and have displacement pistons which each perform a reciprocating motion in operation and are provided for delivery into a common pressure line. The hydrostatic piston machine unit has a jointly assigned precompression volume for the at least two driving mechanisms.

A hydraulic device (1) comprises a housing (2) and a shaft (3) which is rotatable about a first axis of rotation (4). The shaft (3) has a flange (8), a partly spherical portion (16) and a plurality of pistons (9), which are fixed to the flange (8). The device (1) also has a plurality of cylindrical sleeves (11), wherein each sleeve (11) has a sleeve bottom (13) comprising a sleeve opening (14) including a centreline (23). The sleeves (11) cooperate with the pistons (9) to form respective compression chambers (12) of variable volume. A barrel plate (15) is mounted on the partly spherical portion (16) and has barrel plate ports (21) including respective centrelines (22). The sleeves (11) are rotatable about a second axis of rotation (19) which intersects the first axis of rotation (4) by an acute swash angle. The barrel plate (15) is coupled to the shaft (3) in rotational direction thereof by means of a plurality of pin-groove couplings creating a plurality of pivot axes (24) about the second axis of rotation (19). The widths of the grooves (18) allow the pins (17) to move within the respective corresponding grooves (18) in rotational direction about the second axis of rotation (19) under operating conditions. The relative position of the shaft (3) and the barrel plate (15) in rotational direction about the second axis of rotation (19) is adapted such that under operating conditions each centreline (22) of the respective barrel plate ports (21) fluctuates in rotational direction about the second axis of rotation (19) with respect to the centreline (23) of the corresponding sleeve opening (14) within a range in which the centreline (23) of the sleeve opening (14) lies.

A hydrostatic piston machine unit, which is in particular designed as a hydrostatic axial piston machine unit, comprises at least two driving mechanisms that can be driven synchronously and have displacement pistons which each perform a reciprocating motion in operation and are provided for delivery into a common pressure line. The hydrostatic piston machine unit has a jointly assigned precompression volume for the at least two driving mechanisms.

A hydraulic device (1) comprises a housing (2) and a shaft (3) which is rotatable about a first axis of rotation (4). The shaft (3) has a flange (8), a partly spherical portion (16) and a plurality of pistons (9), which are fixed to the flange (8). The device (1) also has a plurality of cylindrical sleeves (11), wherein each sleeve (11) has a sleeve bottom (13) comprising a sleeve opening (14) including a centreline (23). The sleeves (11) cooperate with the pistons (9) to form respective compression chambers (12) of variable volume. A barrel plate (15) is mounted on the partly spherical portion (16) and has barrel plate ports (21) including respective centrelines (22). The sleeves (11) are rotatable about a second axis of rotation (19) which intersects the first axis of rotation (4) by an acute swash angle. The barrel plate (15) is coupled to the shaft (3) in rotational direction thereof by means of a plurality of pin-groove couplings creating a plurality of pivot axes (24) about the second axis of rotation (19). The widths of the grooves (18) allow the pins (17) to move within the respective corresponding grooves (18) in rotational direction about the second axis of rotation (19) under operating conditions. The relative position of the shaft (3) and the barrel plate (15) in rotational direction about the second axis of rotation (19) is adapted such that under operating conditions each centreline (22) of the respective barrel plate ports (21) fluctuates in rotational direction about the second axis of rotation (19) with respect to the centreline (23) of the corresponding sleeve opening (14) within a range in which the centreline (23) of the sleeve opening (14) lies.

A bent-axis hydraulic pump motor includes: a cylinder block, a retainer plate; and a constant velocity joint, which includes an inner joint element; an outer joint element; and a plurality of balls interposed between block-side ball grooves and shaft-side ball grooves to transmit torque between the cylinder block and the retainer plate, so that all block-side groove planes, which include respective extending axial lines of the block-side ball grooves and the inclined rotation center, are inclined with respect to an axial center of a center shaft and all drive shaft-side groove planes, which include respective extending axial lines of the shaft-side ball grooves and the inclined rotation center, are inclined with respect to an axial center of a drive shaft such that loads applied to a cage in an axial direction from the balls are balanced.

A flow divider assembly for use with a hydraulic pump provides flow to separate drive motors for use in a vehicle or other application. A pair of flow divider motors may be mounted on a block and have a common axis of rotation. The ratio between the two may be controlled by adjustment of the angles of the respective thrust bearings of the flow divider motors. A valve may connect the outlet of one of the flow divider motors or the outlet of the other flow divider motor. passage to the second outlet passage. Additional bypass valves may be provided to permit direct connection between the hydraulic pump and the separate drive motors.

A rotary fluid pump-motor includes first and second rotor assemblies and a bent cylinder sleeve. The first rotor assembly includes a first rotor, a piston cylinder, and a flange ring with an inclined guide surface. The second rotor assembly includes a second rotor and a piston. The first and second rotors are rotatably movable about inclined first and second rotor axes, respectively. The bent cylinder sleeve receives the piston cylinder and the piston therein through respective sleeve openings to define a piston chamber therebetween. The bent cylinder sleeve is in at least intermittent contacting relationship with the flange ring's inclined guide surface and rotatably movable about the first rotor axis with respect to the inclined guide surface such that the bent cylinder sleeve moves along the first rotor axis relative to the piston cylinder based upon its circumferential position along the inclined guide surface to correspondingly vary the piston chamber's volume.

A bent-axis machine comprises a housing having a control cover and a piston drum which is rotatably mounted in the housing on a valve plate and which has axial cylinders, each of which receives a piston. An adjustment system includes a pivot cradle via which the piston drum and the valve plate can be pivoted relative to the drive axis about a maximum working range which is delimited by a minimum pivot angle and a maximum pivot angle. The minimum pivot angle of the working range is shifted out of its zero position by at least 5, and the maximum pivot angle is extended in the same way by at least 5 in order to retain the entire working range about the region left out of the lower region.

A bent-axis hydraulic pump motor includes: a cylinder block, a retainer plate; and a constant velocity joint, which includes an inner joint element; an outer joint element; and a plurality of balls interposed between block-side ball grooves and shaft-side ball grooves to transmit torque between the cylinder block and the retainer plate, so that all block-side groove planes, which include respective extending axial lines of the block-side ball grooves and the inclined rotation center, are inclined with respect to an axial center of a center shaft and all drive shaft-side groove planes, which include respective extending axial lines of the shaft-side ball grooves and the inclined rotation center, are inclined with respect to an axial center of a drive shaft such that loads applied to a cage in an axial direction from the balls are balanced.

A hydraulic piston pump motor in which water is used as a working fluid includes an axial directional passage opened on an end surface of one end of a shaft that couples to a cylinder block and drilled open along a shaft center of the shaft; a first radial directional passage drilled open along a radial direction of the shaft from the axial directional passage and configured to guide working fluid into a casing; a second radial directional passage drilled open from the axial directional passage along the radial direction of the shaft at a position closer to the one end of the shaft than the first radial directional passage; and an introduction passage communicating a passage, through which the higher pressure working fluid flows, among the supply passage and the discharge passage with the axial directional passage.