A sliding shoe for supporting a piston of a hydrostatic axial piston machine against a swash plate includes a sliding face that defines a central concentric pressure pocket that is flat in order to stabilize the sliding shoe. The pressure pocket has radial supply grooves in order to ensure an optimal supply of pressure medium to the pressure pocket from a central mouth opening. The radial supply grooves extend through the pressure pocket and as far as a circumferential groove which surrounds the pressure pocket.

The invention relates to a metallic work-piece (2, 5, 6, 14, 20, 23) for a hydraulic device (1, 15). The workpiece (2, 5, 6, 14, 20, 23) comprises a coating layer (12), characterized in that the coating layer (12) contains Mo, in particular metallic Mo, with a weight fraction of at least 1 %

An electro hydrostatic actuator (EHA) comprises a hydraulic pump and an electric motor driving the hydraulic pump. The hydraulic pump comprises an inlet and an outlet for hydraulic fluid and an active fluid flow path arranged therebetween such that, in an active mode of operation when the pump is driven by the electric motor, hydraulic fluid is actively drawn in through the inlet and exhausted out through the outlet. The hydraulic pump further comprises a bypass flow path arranged between the pump inlet and outlet, such that, in a damping mode of operation, hydraulic fluid is able to freely flow between the inlet and outlet in either direction.

A tilting angle control device includes pressure sensors. Each of the pressure sensors outputs to a control unit a pressure command signal corresponding to an operation amount. The control unit outputs to an electromagnetic proportional control valve a pressure control signal corresponding to the pressure command signal, and the electromagnetic proportional control valve outputs to a tilt adjustment mechanism pilot pressure corresponding to the pressure control signal. The tilt adjustment mechanism adjusts a tilting angle of a variable displacement pump such that the tilting angle becomes an angle corresponding to the pilot pressure. A pilot pressure sensor detects the pilot pressure to output a pressure feedback signal to the control unit. The control unit calculates the pressure control signal based on the pressure feedback signal and the pressure command signal and performs feedback control of the pilot pressure.

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 hydraulic piston pump includes a piston disposed in a blind housing bore of a piston housing and that reciprocates to generate a pumping action. To accommodate the piston, a piston cartridge is installed in each of the housing bores. The piston cartridge includes a piston sleeve having an inner sleeve periphery, a first outer sleeve periphery, and a second outer sleeve periphery. The inner sleeve periphery is configured to establish sliding contact with the piston. The first outer sleeve periphery has a first outer sleeve diameter that is larger than a second outer sleeve diameter associated with the second outer sleeve periphery. To seal against the blind housing bore, a liner cap having a cylindrical liner wall and an axial liner cover is disposed over the first outer sleeve periphery. The axial liner cover abuts a housing bore ceiling of the blind housing bore and can receive hydraulic fluid there through.

A pumping device may include a pump housing partially delimiting a working chamber, and a piston arranged therein, axially movable between first and second positions in which the working chamber has maximum and minimum volumes, respectively. The pumping device may include first and second fluid lines for introducing and discharging fluid to/from the working chamber, respectively. The first fluid line may be an annular fluid channel, fluidically connected to the working chamber via a breakthrough formed in the pump housing at an end face of the working chamber opposite the piston, running transversely to the axial direction at least in the area of the breakthrough. The second fluid line may open obliquely into the working chamber in an area of the second position, relative to the axial direction in an end face delimiting the working chamber towards the first fluid line. The pumping device may include first and second valves for fluid-tight closures of the first and second fluid lines, respectively, the second valve communicating fluidically with the working chamber directly.

A fluid end having its fluid flow bores sealed without threading a retaining nut into the walls of each bore. The fluid ends may be assembled using a plurality of different kits that each comprise a fluid end body, a component, a retainer element, and a fastening system. The retainer element holds the component within each of the bores formed in the fluid end body and the fastening system secures the retainer element to the body. The fastening system comprises a plurality of externally threaded studs, washers and nuts in some embodiments. In other embodiments, the fastening system comprises a plurality of screws.

A fluid end having its fluid flow bores sealed without threading a retaining nut into the walls of each bore. The fluid ends may be assembled using a plurality of different kits that each comprise a fluid end body, a component, a retainer element, and a fastening system. The retainer element holds the component within each of the bores formed in the fluid end body and the fastening system secures the retainer element to the body. The fastening system comprises a plurality of externally threaded studs, washers and nuts in some embodiments. In other embodiments, the fastening system comprises a plurality of screws.

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.