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 hydraulic 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 a positions different from each other in the radial direction of the rotation axis.

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 hydraulic 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 a positions different from each other in the radial direction of the rotation axis.

A valve plate assembly (1) of a hydraulic axial piston machine is described, the valve plate assembly comprising a wear plate (2) made of a ceramic material surrounded by a compression ring (4). Such a valve plate assembly should be produced and maintained in a cost-effective manner. To this end, the wear plate (2) is connected to a support plate (3) by means of the compression ring (4).

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.

A hydraulic machine includes a first member (1) having a first structure (2) for a hydraulic medium opening in a first interface surface (3) and a second member having a second structure for the hydraulic medium opening in a second interface surface is described, the first interface surface (3) being in contact with the second interface surface, wherein at least one of the members (1) is provided with a support element (6) surrounding the member (1). Such a machine should have a good efficiency. To this end the support element (6) has a strength varying in circumferential direction around the member (1) and/or in thickness direction in a middle region of the member (1).

A control plate for an axial piston machine is disclosed. The control plate includes a control face on which at least one kidney-shaped high-pressure control opening extending axially through the control plate and at least one kidney-shaped low-pressure control opening extending axially through the control plate is formed and which defines a first sealing ridge which is formed radially inside the at least one high-pressure control opening and the at least one low-pressure control opening, and a second sealing ridge which is formed radially outside the at least one high-pressure control opening and the at least one low-pressure control opening. In this case, the second sealing ridge is wider in the radial direction, preferably in some portions, than the first sealing ridge. Additionally, an axial piston machine in a swash plate design is disclosed. The axial piston machine includes a control plate which has at least one kidney-shaped high-pressure control opening and at least one kidney-shaped low-pressure control opening, by way of which piston recesses of a cylinder drum which is rotatably mounted in a housing of the axial piston machine can be connected alternately to a high-pressure connection and a low-pressure connection during rotation of the cylinder drum. In this case, a first, radially inner sealing ridge and a second, radially outer sealing ridge, which is designed to be wider in the radial direction, preferably in some portions, than the first sealing ridge, are formed on a contact face between the control plate and the cylinder drum.

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 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 hydraulic machine includes a housing interior space and a group of hydrostatic working chambers which are mounted in said housing interior space so as to be rotatable about an axis of rotation and which, as the group rotates, are connectable alternately to a high pressure and to a low pressure of the hydraulic machine and exhibit leakage into the housing interior space. A heat exchanger device is accommodated in the housing interior space. The hydraulic machine may be associated with a hydraulic assembly and a hydraulic axle.

A hydraulic machine includes a housing interior space and a group of hydrostatic working chambers which are mounted in said housing interior space so as to be rotatable about an axis of rotation and which, as the group rotates, are connectable alternately to a high pressure and to a low pressure of the hydraulic machine and exhibit leakage into the housing interior space. A heat exchanger device is accommodated in the housing interior space. The hydraulic machine may be associated with a hydraulic assembly and a hydraulic axle.