A swashplate-type axial piston machine includes a housing and at least one working channel extending through a distributor plate. The at least one working channel opens out at an outside on the housing at an associated working port. The at least one working channel includes a first section and a second section. The first section extends over the entire distributor plate. The second section is arranged entirely in the housing. The second section directly adjoins the first section. A first rotary bearing has an outer circumferential surface that defines a circular cylindrical reference cylinder about the axis of rotation.

A hydrostatic axial piston machine includes a cylinder drum that rotates during operation and has a plurality of cylinder bores in which displacement pistons are arranged, each of which opens out in a control opening in one end face of the cylinder drum, and having a control part against which the cylinder drum bears with the end face and on which two kidney-shaped control ports in the form of circular arcs are provided. Between the two kidney-shaped control ports, a first changeover web and a second changeover web are formed, wherein two sets of compensating openings that are able to be overlapped by control openings are located in the changeover webs with one compensating opening of each set located in each changeover web, and the compensating openings in the two sets of compensating openings are connected together via respective compensating fluid paths.

A hydraulic fan drive includes an adjustable variable-displacement pump by which a pressurized fluid can be sucked in and can be delivered via a pump pressure port and which has, for adjustment of the delivery volume, an adjustment device with an actuation chamber, which is delimited by an actuation surface of an adjustment piston and to which a pressurized fluid can be supplied for increasing the delivery volume and from which pressurized fluid can be displaced for reducing the delivery volume. The adjustment device further includes a counter chamber, which is delimited by a counter surface, smaller in cross section in comparison with the actuation surface, of an adjustment piston and can be acted on by pump pressure. The adjustment device also includes an actuation spring, which acts so as to adjust the delivery volume toward an extreme value.

An axial piston machine has a swash plate and an adjusting device having an adjusting cylinder and a double-acting adjusting piston which is longitudinally movable in the adjusting cylinder and includes a piston and a piston rod, which is fixedly connected to the piston and is articulated to the swash plate. The joint between the adjusting piston and the swash plate is a movable swivel joint having a joint body receptacle on one part and a joint body on the other part of the adjusting piston and the swash plate. The joint body is closely guided in the joint body receptacle in the direction of movement of the adjusting piston, is to rotatable about an axis of rotation running parallel to the pivot axis of the swashplate, and is movable with a directional component perpendicular to the direction of movement of the adjusting piston and perpendicular to the axis of rotation.

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 rotary type valve plate compressor may include a shaft, a housing through which the shaft passes, a plurality of cylinders mounted in the housing, a piston received in the cylinder and to be moved forward and rearward in response to rotational operation of a swash plate, and a rotary type valve plate to receive a rotational force of the shaft and to open and close a refrigerant passage hole through which refrigerant passes, based on a phase of the piston.

A rotary type valve plate compressor may include a shaft, a housing through which the shaft passes, a plurality of cylinders mounted in the housing, a piston received in the cylinder and to be moved forward and rearward in response to rotational operation of a swash plate, and a rotary type valve plate to receive a rotational force of the shaft and to open and close a refrigerant passage hole through which refrigerant passes, based on a phase of the piston.

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 machine is described comprising a first part (1, 4) and a second part (7, 8), wherein the first part (1, 4) and the second part (7, 8) are movable relatively to each other in abutting relation, the first part (1, 4) comprises a pressure chamber (2) having a pressure chamber opening (6) in a contact face (5) contacting a sealing face (9) of the second part (7, 8), the second part (7, 8) comprises a low pressure area (10) connected to a low pressure opening (11) in the sealing face (9) and a high pressure area (12) connected to a high pressure opening (13) in the sealing face (9), wherein during a movement of the first part (1, 4) with respect to the second part (7, 8) in a moving direction (14) the pressure chamber opening (6) comes alternatingly in overlap with the low pressure opening (11) and the high pressure opening (13). Such a machine should be flexible in operation with low risk of damages caused by cavitation. To this end a throttling channel (15) in the second part (7, 8) connects the low pressure area (10) with an area in the sealing face (9) in moving direction in front of the low pressure opening (11).