A hydrostatic axial piston machine includes a pressing pressure chamber for the cylinder drum which is supplied with pressing pressure from a circular-arc-like elongate hole of a distributor plate or from a plurality of connection channels of the cylinder drum. The pressing pressure chamber is delimited radially outwardly by the cylinder drum and radially inwardly by the drive shaft. The pressing pressure chamber is delimited axially at both sides by seals which are both arranged between the radially inner rotating drive shaft and a radially outer stationary component. The radially outer component may be the cylinder drum or, in the case of the distributor-plate-side seal, also a gap seal between the drive shaft and a bearing bush of the distributor plate. Both seals are arranged at the distributor plate side with respect to a tooth arrangement or a retraction ball.

A hydrostatic axial piston machine includes a pressing pressure chamber for the cylinder drum which is supplied with pressing pressure from a circular-arc-like elongate hole of a distributor plate or from a plurality of connection channels of the cylinder drum. The pressing pressure chamber is delimited radially outwardly by the cylinder drum and radially inwardly by the drive shaft. The pressing pressure chamber is delimited axially at both sides by seals which are both arranged between the radially inner rotating drive shaft and a radially outer stationary component. The radially outer component may be the cylinder drum or, in the case of the distributor-plate-side seal, also a gap seal between the drive shaft and a bearing bush of the distributor plate. Both seals are arranged at the distributor plate side with respect to a tooth arrangement or a retraction ball.

An axial piston pump has a fluid inlet, a fluid outlet, and a rotatable, one-piece piston housing carrying one or more pistons movable within one or more respective sleeves formed by the housing. A circumferential row of fixed field members is mounted to the housing at a mounting location formed by the housing, the mounting location being radially outward of the sleeve(s). The pump further has a stator surrounding the piston housing and including a circumferential row of armature windings such that the piston housing and the stator form an electro-magnetic motor operable to rotate the piston housing, and a swashplate engaged with the piston(s) such that rotation of the piston housing relative to the swashplate around an axis of rotation produces reciprocating movement of the piston(s) for the pressurisation of fluid received into the sleeve(s) from the fluid inlet and then discharged from the sleeve(s) to the fluid outlet.

A piston pump includes a ported member that is moveably disposed within an internal space of a housing between a rotating group and the housing. The ported member includes a first face facing the rotating group and a second face facing a fluid inlet and outlet. The ported member includes an intake port and a discharge port. Moreover, the ported member includes a balance aperture configured to pass fluid between the biasing member and a pump chamber as the rotating group rotates within the internal space such that the biasing member biases the ported member toward a balanced position within the internal space. The balance aperture has a rim at the first face. The rim is clefted at a relief feature of the first face. The relief feature is recessed into the first face.

A piston pump includes a ported member that is moveably disposed within an internal space of a housing between a rotating group and the housing. The ported member includes a first face facing the rotating group and a second face facing a fluid inlet and outlet. The ported member includes an intake port and a discharge port. Moreover, the ported member includes a balance aperture configured to pass fluid between the biasing member and a pump chamber as the rotating group rotates within the internal space such that the biasing member biases the ported member toward a balanced position within the internal space. The balance aperture has a rim at the first face. The rim is clefted at a relief feature of the first face. The relief feature is recessed into the first face.

A hydrostatic axial piston machine includes a pressing pressure chamber for the cylinder drum which is supplied with pressing pressure from a circular-arc-like elongate hole of a distributor plate or from a plurality of connection channels of the cylinder drum. The pressing pressure chamber is delimited radially outwardly by the cylinder drum and radially inwardly by the drive shaft. The pressing pressure chamber is delimited axially at both sides by seals which are both arranged between the radially inner rotating drive shaft and a radially outer stationary component. The radially outer component may be the cylinder drum or, in the case of the distributor-plate-side seal, also a gap seal between the drive shaft and a bearing bush of the distributor plate. Both seals are arranged at the distributor plate side with respect to a tooth arrangement or a retraction ball.

A hydraulic axial piston machine (1) is described, the machine comprising a housing, a cylinder block (2) rotatably mounted in the housing about an axis or rotation (7) and having at least one cylinder (3), and a valve arrangement (4) between the cylinder block (2) and the housing, the valve arrangement having a first part (4) rotating with the cylinder block (2) and a second part mounted stationary with respect to the housing. Such a machine should have a high efficiency. To this end the first part (4) comprises an elastically deformable spring section (9).

A connector plate, for mechanically and hydraulically connecting a hydraulic machine with a hydraulic attachment part, includes a plurality of hydrostatic connector recesses. Each recess has a first side that includes a first orifice opening to the hydraulic attachment part, and a second side with a second orifice opening to the hydraulic machine. The plurality of orifices are arranged so as to open in a substantially axially parallel manner with respect to a drive shaft of the hydraulic machine. A hydraulic machine includes such a connector plate, and a hydrostatic unit includes such a hydraulic machine and a hydraulic attachment part.

A connector plate, for mechanically and hydraulically connecting a hydraulic machine with a hydraulic attachment part, includes a plurality of hydrostatic connector recesses. Each recess has a first side that includes a first orifice opening to the hydraulic attachment part, and a second side with a second orifice opening to the hydraulic machine. The plurality of orifices are arranged so as to open in a substantially axially parallel manner with respect to a drive shaft of the hydraulic machine. A hydraulic machine includes such a connector plate, and a hydrostatic unit includes such a hydraulic machine and a hydraulic attachment part.

A hydrostatic axial piston machine includes a housing, a connection plate closing the housing, working connections formed on the connection plate, a drive shaft, a swashplate, a cylinder drum coupled to the shaft in the direction of rotation, bores formed in the drum and each including a piston, a control plate against which the drum bears, a retraction plate for removing a piston from the bores, and a retraction ball arranged in front of the first end face of the drum which surrounds a drum neck of the drum and the shaft and by which the retraction plate is loaded in the direction of the swashplate. A pressure chamber is defined by seals between the retraction ball, the drum, and the shaft, and is configured to be acted upon by a pressure above a housing pressure. The retraction ball is sealed against the drum neck and against the shaft.