A rotatable piston assembly for a reciprocating piston type hydraulic machine includes a rotatable piston configured for a controlled rotation and configured to reciprocate within a cylinder bore of the reciprocating piston type hydraulic machine.

A rotatable piston assembly for a reciprocating piston type hydraulic machine includes a rotatable piston configured for a controlled rotation and configured to reciprocate within a cylinder bore of the reciprocating piston type hydraulic machine.

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 swash-plate type piston pump motor includes: a rotary shaft; a cylinder block that rotates together with the rotary shaft; a plurality of pistons (5) each of which is inserted so as to be reciprocable in each of a plurality of cylinders formed in the cylinder block; a plurality of piston shoes (6) attached so as to be swingable to an end portion (501) of each piston; a swash plate (7) inclined with respect to an axis of the rotary shaft and having a sliding surface (41) being in contact with a plurality of piston shoes; and a shoe retainer (8) configured to press the piston shoe against the sliding surface. Each piston shoe includes a shoe body (71) being in contact with a sliding surface, and an elastic body (79) provided between the shoe body and the shoe retainer.

A swash-plate type piston pump motor includes: a rotary shaft; a cylinder block that rotates together with the rotary shaft; a plurality of pistons (5) each of which is inserted so as to be reciprocable in each of a plurality of cylinders formed in the cylinder block; a plurality of piston shoes (6) attached so as to be swingable to an end portion (501) of each piston; a swash plate (7) inclined with respect to an axis of the rotary shaft and having a sliding surface (41) being in contact with a plurality of piston shoes; and a shoe retainer (8) configured to press the piston shoe against the sliding surface. Each piston shoe includes a shoe body (71) being in contact with a sliding surface, and an elastic body (79) provided between the shoe body and the shoe retainer.

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.

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.

An axial piston device may be operated as a pump and includes a self-centering rotary valve. The device includes a stationary housing encompassing a shaft and the rotary valve. The rotary valve and the shaft are coupled to each other. Upon rotation, the rotary valve self-centers as a result of elimination of moments and forces within the pump. The inventive pump is a piston device. The valve is within a valve bore, which is a part of a manifold. A shaft is within the manifold and the shaft is attached at its distal end to a planar surface of the rotary valve. The shaft has a first axis of rotation and the rotary valve has a second axis of rotation. During operation of the pump, the first axis is often times offset from the second axis. The pump operates via a swashplate with reciprocating pistons while the housing remains stationary.

An axial piston device may be operated as a pump and includes a self-centering rotary valve. The device includes a stationary housing encompassing a shaft and the rotary valve. The rotary valve and the shaft are coupled to each other. Upon rotation, the rotary valve self-centers as a result of elimination of moments and forces within the pump. The inventive pump is a piston device. The valve is within a valve bore, which is a part of a manifold. A shaft is within the manifold and the shaft is attached at its distal end to a planar surface of the rotary valve. The shaft has a first axis of rotation and the rotary valve has a second axis of rotation. During operation of the pump, the first axis is often times offset from the second axis. The pump operates via a swashplate with reciprocating pistons while the housing remains stationary.