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.

The present invention addresses the problem of providing a swash-plate hydraulic motor or a swash-plate hydraulic pump having a structure in which the swash plate can be stably held without mounting a shoe to the swash plate-side end of a tilt control piston. An example of the embodiment of the present invention is a swash-plate hydraulic motor (1). A spherical section (8b) is integrally formed on the swash plate-side end surface of a tilt piston (8), and a groove (10) into which the spherical section (8b) is fitted in a slidable manner is formed in the support surface (7b) (second support surface (7b2)) of the swash plate (7). The groove (10) is a part of the second support surface (7b2) and has a shape having a predetermined width and having a longitudinal direction which is oriented perpendicularly to the direction which connects two pivots (11).

Systems and methods for a variable displacement hydraulic motor. The hydraulic motor, in one example, includes a swash plate with a tilt angle, multiple piston assemblies configured to rotate about a drive shaft. In the motor, each of the piston assemblies includes an inner piston slideably coupled to an outer piston that mates with a cylinder in a cylinder block and a retainer device configured to inhibit axial movement of the outer piston in a first position and permit axial movement of the outer piston in a second position.

Systems and methods are provided for a hydraulic axial piston assembly. The hydraulic axial piston assembly may include a distributor plate, a bearing element directly and orthogonally connected to a side of the distributor plate, and an adjustment screw orthogonally connected to the bearing element, where the adjustment screw is externally accessible and manually rotatable to adjust a timing angle of the distributor plate.

Systems and methods are provided for a hydraulic axial piston assembly. The hydraulic axial piston assembly may include a distributor plate, a bearing element directly and orthogonally connected to a side of the distributor plate, and an adjustment screw orthogonally connected to the bearing element, where the adjustment screw is externally accessible and manually rotatable to adjust a timing angle of the distributor plate.

In an embodiment, a variable flow pump may include a swashplate rotatably driven by a driveshaft. The swashplate may be movable between a first and second tilt angle relative to the driveshaft. A piston pump may be reciprocatingly driven by the swashplate based upon, at least in part, the tilt angle of the swashplate. An actuator piston may be moveable between a first and second position based upon, at least in part, a downstream backpressure of a fluid pumped by the piston pump. An actuator assembly may be moveable between a first and second position based upon, at least in part, the position of the actuator piston. The actuator assembly may include a swashplate driver configured urge the swashplate between the first and second tilt angles, and a biasing driver configured to apply a force urging the swashplate into contact with the swashplate driver.

A manifold for a pump is configured to connect to a jacket to form a reservoir and to connect to at least one pumping mechanism disposed within the reservoir. The manifold includes a first side including a first side surface configured to face the reservoir and a second side including a second side surface. The manifold also includes a bypass passage, at least one push rod guide bore extending through the first side surface and the second side surface, and a leakage passage fluidly connecting the at least one push rod guide bore to an outlet disposed outside the first side surface. The manifold further includes a discharge passage including at least one inlet disposed in the first side surface, and the at least one inlet is configured to receive fluid pumped by the at least one pumping mechanism.

A manifold for a pump is configured to connect to a jacket to form a reservoir and to connect to at least one pumping mechanism disposed within the reservoir. The manifold includes a first side including a first side surface configured to face the reservoir and a second side including a second side surface. The manifold also includes a bypass passage, at least one push rod guide bore extending through the first side surface and the second side surface, and a leakage passage fluidly connecting the at least one push rod guide bore to an outlet disposed outside the first side surface. The manifold further includes a discharge passage including at least one inlet disposed in the first side surface, and the at least one inlet is configured to receive fluid pumped by the at least one pumping mechanism.

An axial piston machine may include a shaft and a housing surrounding at least a portion of the shaft. A cylinder arrangement may be disposed within the housing in a circular manner. The cylinder arrangement may include a plurality of cylinders and a plurality of pistons each extending within each of the plurality of cylinders and may be constructed and arranged to drive the shaft. The plurality of cylinders may each include an expansion volume with an inlet and at least one outlet opening for a working medium. A cylinder head may be provided on the housing and may be constructed and arranged to close the plurality of cylinders of the cylinder arrangement. A cavity may be defined around the shaft in a central region of the cylinder arrangement and may be in operative communication with a plurality of auxiliary outlet openings of the expansion volume of each of the plurality of cylinders via a temporary connection. A cylindrical roller slider may rotate within the cavity in the central region of the cylinder arrangement and may be constructed and arranged to drive the shaft. A temporary connection between the cavity and the expansion volume of each of the plurality of cylinders may be formed by at least one of a channel through the cylindrical roller slider and a recess on an outside surface of the cylindrical roller slider. The recess may extend laterally from a casing of the cylindrical roller slider at a height of the plurality of auxiliary outlet openings in each of the plurality of cylinders and at a distance to the cavity in the central region of the cylinder arrangement.

A variable-displacement engine comprises an engine block, power shaft and rotating cylinder block. Pistons and connecting rods mounted in the cylinder block connect to a wobble plate having a rotating ring portion and non-rotating ring portion connected to allow relative rotation therebetween while constraining the portions to remain parallel. The wobble plate defines an inclination plane, pivot axis and wobble plate angle . A piston control mechanism includes axial lift, control lever supported by the lift and by an anchor bearing, and links connecting the control lever to the wobble plate. Axial movement of the lift changes the axial position of the control lever pivot and changes the control lever angle, in turn changing, via the connecting links, the wobble plate angle and the axial position of the wobble plate pivot axis. This changes the piston displacement of the engine while maintaining substantially constant compression ratio.