A rotary compressor includes a cylinder having a cylinder chamber and bush groove, a piston housed in the cylinder chamber, a blade formed with the piston to separate the cylinder chamber into low and high pressure chambers, and a pair of bushes. The bushes are fitted in the bush groove with flat surfaces facing each other to hold the blade. The flat surface of at least the bush on the low-pressure side has a crowned portion starting from a position closer to the back pressure space than a swing center position, and extending toward an edge of the bush closer to the cylinder chamber. The swing center position is where a gap between the blade and the bush is constant while the piston rotates eccentrically.

A pump body assembly and a compressor are provided. The pump body includes: a spindle, wherein the spindle has a sliding vane chute, a back pressure oil cavity being at least a part of an oil passage is located at a tail end of the sliding vane chute, an oil outlet of the back pressure oil cavity is located at the top of the back pressure oil cavity, and a position of the oil inlet of the back pressure oil cavity is lower than that of an oil outlet of the back pressure oil cavity such that a lubrication medium enters the back pressure oil cavity through the oil inlet of the back pressure oil cavity and fills up the back pressure oil cavity and flows out from the top of the back pressure oil cavity.

A rotary compressor includes: a compressor housing stores lubricating oil; a compression unit compresses the refrigerant; and a motor drives the compression unit. The compression unit includes a cylinder, an upper end plate and a lower end plate, a main bearing provided on the upper end plate, a sub bearing provided on the lower end plate, a rotary shaft supported by the main bearing and the sub bearing, and a piston fitted to the rotary shaft. An inner peripheral surface of a shaft hole of the sub bearing is provided with an oil-supply groove having a helical shape that supplies the lubricating oil from a lower end to an upper end of the shaft hole, and the oil-supply groove is inclined with respect to the rotary shaft in a rotating direction and extends from the lower end toward the upper end of the rotary shaft in the rotating direction.

A variable displacement rotary vane pump. The pump has a pump body, a rotor with vanes that rotates inside the pump body around a rotation axis, an oscillating stator arranged in an eccentric position around the rotor, a fulcrum for the rotation of the oscillating stator with respect to the pump body, and adjusting means for adjusting the displacement of the pump. The adjusting means act on the oscillating stator to move it with respect to the rotor and the pump body. The fulcrum is integrally formed with the oscillating stator and is housed in a recess formed in the pump body. The pump has a sliding element between the fulcrum and the recess. The sliding element is at least partially free to rotate within the recess.

Scroll fluid machine (1) in which the dislodgement of a slide bush (56) and a spring (61), which are provided in an eccentric bush (36), is prevented. Provided in receiving hole (58) of eccentric bush (36) are slide bush (56), which is movable in the direction of eccentricity, and spring (61), which biases slide bush (56) in a moving direction. A spring holding section (56b) and engagement projections (56a) are formed on slide bush (56). After slide bush (56) is placed in the receiving hole (58), engagement projections (56a) engage with eccentric bush (36) in a state in which slide bush (56) has been moved by the biasing force of spring (61), thus preventing slide bush (56) from falling off the receiving hole (58), and the spring holding section (56b) prevents the spring (61) from falling off the receiving hole (58).

An internal gear pump includes a housing having a pump chamber in which an inner rotor and an outer rotor are arranged. A suction port in communication with a suction path and a discharge port in communication with a discharge path are formed at the housing. The pump chamber includes an inner wall having a suction region at a suction port-side and a discharge region at a discharge port-side. The suction region includes a first suction region extending towards the suction path from a pressing point, where the outer rotor is pressed when the internal gear pump is in operation, and a second suction region between the first suction region and the discharge region. A groove that enlarges a clearance between the outer rotor and the inner wall is formed in the first suction region, but the groove is not formed in the second suction region.

A pump is described, including: a drive shaft including a rotor; a first housing part and a second housing part, between which a pump chamber is formed, in which the rotor is arranged; a rotary bearing via which the drive shaft is mounted on the first housing part such that it can rotate about its rotational axis; and a passage including a first opening and a second opening, wherein the rotary bearing is arranged between the pump chamber and the first opening, and the second opening of the passage emerges onto the side of the second housing part which faces away from the pump chamber.

Methods and apparatus pertaining to positive displacement pumps, and further to hydraulic actuation systems. In some embodiments the pumps are gear pumps with bi-directional operation. In some embodiments the actuation system includes a motor-driven, reversible operation gear pump providing fluid under pressure to a rod and cylinder.

A scroll compressor includes a balancer that rotates integrally with a rotary shaft. A bushing includes a cylindrical portion and an auxiliary weight portion. The auxiliary weight portion is arranged on the outer side of the cylindrical portion. The fitting hole is provided at a position where a moment about the eccentric shaft generated by a centrifugal force acting on the movable scroll due to rotation of the rotary shaft and a moment about the eccentric shaft generated by a centrifugal force acting on the auxiliary weight portion due to rotation of the rotary shaft are in the opposite directions. As viewed in the axial direction of the rotary shaft, the center of gravity of the bushing is located on the same side of a straight line including the center of the cylindrical portion and the center of the rotary shaft as the center of the eccentric shaft.

A dual-section gear pump that enhances compactness of the design includes two pump sections separated by a divider. Each pump section includes a pump cavity and a gear set configured to convey fluid from an intake side to a discharge side of the respective pump cavities. The divider includes a fluid flow passage that enables the two pump sections to share common intake flow via the flow passage provided across the divider. The divider also is configured to enable each gear set in each pump section to provide independent pressurization of the fluid in each pump section, which is discharged from each pump cavity via separate outlets. The gear pump is configured to provide suitable sealing between each pump section and support of the respective gear sets in each pump section while enhancing compactness of the design.