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.

An articulated coupling is provided for a piston sealing device for a piston which includes a fixed skirt and a sliding skirt interconnected by a mechanical inter-skirt connection for axially compressing a continuous extensible segment under the action of a sliding skirt spring, the coupling replacing, on the one hand, the fixed skirt by a ball-joint skirt and providing, on the other hand, a troncospherical piston end which cooperates with a skirt troncospherical bearing surface provided on the ball joint skirt while an articulation unit interposed between the inter-skirt mechanical connection and the piston and/or between the connection and the sliding skirt.

A refrigeration device includes a compressor, a condenser, an expansion valve, an evaporator, intake electromagnetic valves and exhaust electromagnetic valves, two-position three-way electromagnetic valves or two-position five-way electromagnetic valves, a cylinder group, a volume-variable airproof container, two-position two-way electromagnetic valves and a generator. The cylinder group is composed of two or more cylinders, refrigerant flows successively through the compressor, the intake electromagnetic valves, the cylinder group, the exhaust electromagnetic valves, the condenser, the expansion valve and the evaporator and finally enters the compressor from the evaporator, the cylinder group can do work to generate electricity through atmospheric pressure in the volume-variable airproof container and compensates for electric energy consumed by the compressor, and therefore the electric energy can be saved.

The invention concerns a hydraulic piston machine, in particular a water hydraulic machine, with at least one cylinder, in which a piston (4) is arranged to reciprocate, the piston (4) comprising a hollow that is surrounded by an annular wall and has one open end. It is endeavored to keep cavitations small. For this purpose, a filling member (13) is arranged in the hollow (12), the filling member (13) having at least a radial projection (22) and the annular wall (16) having at least a radial depression (17) in the inside facing the hollow (12), or the annular wall (16) having a radial projection and the filing member (13) having a radial depression, the depression having a restraint (19), at least at the end adjacent to the open end (18) of the hollow (12), and the projection (22) and the depression (17) engaging each other.

A hydrostatic axial piston machine includes a housing, a cylinder barrel, and a drive shaft, which are connected together and mounted in the housing so as to rotate jointly about a first axis. The machine also includes a swash plate mounted in the housing so as to pivot about a second axis to adjust a swept volume of the machine. The machine further includes a hydraulic actuating apparatus, which has an actuating piston that delimits an actuating chamber. The machine also includes a regulating valve attached to a flange face of the housing. The regulating valve has connections situated in the flange face that are used to communicate hydraulic fluid to and from the actuating chamber. The flange face is arranged obliquely so as to enclose an angle with the second axis that is greater than 0 and smaller than 90.

Systems and methods for a hydraulic machine. The hydraulic machine includes, in one example, a rotational shaft, a central pin rotationally coupled to the rotational shaft and threadingly engaged with a cylinder block via a threaded interface, and pistons coupled to the rotational shaft and mated with cylinders in the cylinder block. The hydraulic machine further includes a distribution plate in fluidic communication with the cylinders and a fluid inlet and a fluid outlet.

A hydraulic pump, in particular an adjustable axial piston pump, has at least one piston (22) movable in a reciprocating manner in a longitudinal direction within a pump housing during operation of the hydraulic pump. The piston (22) has a link head (24), a piston top (54) opposite the link head (24), and at least one hollow chamber (60) surrounded at least partially by a piston housing (62) that substantially or completely terminates each hollow chamber (60) towards the outside. A piston (22) for such hydraulic pump is also provided.

A method for coating a pump component (23, 31), in particular, a part of an axial piston pump (7), having the steps of providing a blank of the component (23, 31), providing at least one recess in the blank, filling a powdery coating material into the associated recess, melting the coating material under a protective gas atmosphere and material-removing processing of the blank to form at least one sliding and/or bearing surface (6) from the coating.

An axial piston pump has a swash-plate construction, in particular for hydraulic systems. A cylinder drum (3) can be rotationally driven about a rotational axis (7) in a pump housing (1). Pistons (9) are axially displaceable and support at their actuation ends a swash plate (15). The swash plate can be pivoted by an adjusting device (21) to the desired angles of inclination relative to the rotational axis (7) for adjusting the stroke of the pistons (9) and the fluid pressure generated. The adjusting device has an adjusting piston (35) in a hydraulically actuated adjusting cylinder (31). Their movement can be transmitted to the swash plate (15) by a driven connection having a pivot joint (37, 39; 29, 43). The pivot joint is formed by a ball joint (37, 39) arranged between the piston (35) and the piston rod (41) of the adjusting cylinder (31).

A refrigeration device includes a compressor, a condenser, an expansion valve, an evaporator, intake electromagnetic valves and exhaust electromagnetic valves, two-position three-way electromagnetic valves or two-position five-way electromagnetic valves, a cylinder group, a volume-variable airproof container, two-position two-way electromagnetic valves and a generator. The cylinder group is composed of two or more cylinders, refrigerant flows successively through the compressor, the intake electromagnetic valves, the cylinder group, the exhaust electromagnetic valves, the condenser, the expansion valve and the evaporator and finally enters the compressor from the evaporator, the cylinder group can do work to generate electricity through atmospheric pressure in the volume-variable airproof container and compensates for electric energy consumed by the compressor, and therefore the electric energy can be saved.