One embodiment of a hub feed oil system is used to provide oil to components on the rotating side of an aircraft rotor hub system. A pump is configured so that a portion of the pump rotates with the rotating portion of the rotor system and a portion of the pump is fixed relative to the static portion of the rotor system. Multiple oil channels—with the provision of a variety of different pressures—may be provided.

One embodiment of a hub feed oil system is used to provide oil to components on the rotating side of an aircraft rotor hub system. A pump is configured so that a portion of the pump rotates with the rotating portion of the rotor system and a portion of the pump is fixed relative to the static portion of the rotor system. Multiple oil channels—with the provision of a variety of different pressures—may be provided.

A piston (1) having a piston shaft (2), a ball head (3) at one end of the piston shaft (2), and a slider shoe (4) mounted to the ball head (3), wherein the ball head (3) has a through channel (5), the slider shoe (4) has a sliding surface (6) and a through hole (7) in communication with an end of the through channel (5), and a plastic material (8) is arranged in a gap between the slider shoe (4) and the ball head (3) and forms an inner coating (9) of the through hole (7). The production of such a piston should be facilitated. To this end a sealing surface (14) is arranged at the end of the through channel (5) wherein the sealing surface (14) surrounds the opening of the through channel (5) into the through bore (7) and an inner diameter of the sealing surface (14) is smaller than an inner diameter of the inner coating (9) of the through bore (7).

A piston (1) of a hydraulic piston machine is described, the piston (1) having a hollow (2) surrounded by a wall (3) and an insert (4) arranged in the hollow (2). Such a piston is used to have a piston machine with high efficiency at low costs. To this end at least two pliable rings (12, 13) are arranged between the insert (4) and the wall (3).

A piston (1) of a hydraulic piston machine is described, the piston (1) having a hollow (2) surrounded by a wall (3) and an insert (4) arranged in the hollow (2). Such a piston is used to have a piston machine with high efficiency at low costs. To this end at least two pliable rings (12, 13) are arranged between the insert (4) and the wall (3).

An ultra-long stroke multi-cylinder reciprocating pump comprises a small gear, a large gear, a crankshaft, connecting rods, fixed racks, a frame, translation pinions, movable racks, clamps, piston rods, cylinder sleeves, pistons, suction valves, liquid discharging valves, guide rails, a prime motor, a coupling, and a small gear shaft. When the prime motor rotates, the small gear is meshed with the large gear to drive the crankshaft to rotate, an axial center of the translation pinion is driven by the connecting rod to move reciprocally, the translation pinion is meshed with the fixed rack and the movable rack simultaneously, and a distance of reciprocating motion of the movable rack is twice a distance of reciprocating motion of a rotation center of the translation pinion, so that an ultra-long stroke is realized.

An ultra-long stroke multi-cylinder reciprocating pump comprises a small gear, a large gear, a crankshaft, connecting rods, fixed racks, a frame, translation pinions, movable racks, clamps, piston rods, cylinder sleeves, pistons, suction valves, liquid discharging valves, guide rails, a prime motor, a coupling, and a small gear shaft. When the prime motor rotates, the small gear is meshed with the large gear to drive the crankshaft to rotate, an axial center of the translation pinion is driven by the connecting rod to move reciprocally, the translation pinion is meshed with the fixed rack and the movable rack simultaneously, and a distance of reciprocating motion of the movable rack is twice a distance of reciprocating motion of a rotation center of the translation pinion, so that an ultra-long stroke is realized.

A sliding member including, a support layer and a sliding layer provided on a side of one end surface of the support layer configured to slide on a mating member, the sliding layer having a hardness set higher toward an outer side than at a center in an axial direction.

A pump adapted for use in desalination systems that has four cylinders, with a double acting piston in each cylinder. Each cylinder and piston thereby defines a feed chamber and a recovery chamber. The pistons are connected to a common drive. The connection to the common drive is such that the pistons reciprocate in a sequence equally spaced in time. Reciprocating valving for each piston is driven by the common drive to be 90 degrees out of phase with the respective piston. The valving connects the recovery chamber alternately to an inlet manifold for an intake stroke of the piston relative to the recovery chamber, and to an outlet manifold for a discharge stroke of the piston relative to the recovery chamber. There is a brief period of closure coinciding with top dead centre and bottom dead centre of the piston, during which the recovery chamber is blocked off from both the inlet and outlet manifolds. The reciprocating valving is midway between its top dead centre and bottom dead centre during the period of closure.

A pump adapted for use in desalination systems that has four cylinders, with a double acting piston in each cylinder. Each cylinder and piston thereby defines a feed chamber and a recovery chamber. The pistons are connected to a common drive. The connection to the common drive is such that the pistons reciprocate in a sequence equally spaced in time. Reciprocating valving for each piston is driven by the common drive to be 90 degrees out of phase with the respective piston. The valving connects the recovery chamber alternately to an inlet manifold for an intake stroke of the piston relative to the recovery chamber, and to an outlet manifold for a discharge stroke of the piston relative to the recovery chamber. There is a brief period of closure coinciding with top dead centre and bottom dead centre of the piston, during which the recovery chamber is blocked off from both the inlet and outlet manifolds. The reciprocating valving is midway between its top dead centre and bottom dead centre during the period of closure.