Abstract: An embodiment provides a vane pump device. In the vane pump device, vane grooves of a rotor include columnar grooves which accommodate oil, and support the vanes. An inner-plate low pressure side recess portion is provided in an end surface of an inner plate along a rotation direction, and supplies oil to the columnar grooves. An outer-plate low pressure side through-hole and an outer-plate low pressure side recess portion are provided in an end surface of an outer plate along the rotation direction, and supply oil to the columnar grooves at a position facing the inner-plate low pressure side recess portion. An opening area of the inner-plate low pressure side recess portion is equal to a sum of opening areas of the outer-plate low pressure side through-hole and the outer-plate low pressure side recess portion.

Abstract: A roots type fluid machine includes a case having a side wall, a pair of rotary shafts provided in the case, a pair of rotors engaged with each other and fixed to the pair of rotary shafts so as to extend axially, respectively, a suction space formed by the case and the pair of rotors for introducing fluid, a discharge space formed by the case for discharging fluid and the pair of rotors and a transfer chamber formed by the case and the rotor. The rotor has a rotor end surface. A clearance is formed between the side wall and the rotor end surface. The transfer chamber transfers gas introduced in the suction space to the discharge space in accordance with the rotation of the pair of rotors. The case has a guide groove formed in the side wall facing the rotor end surface. Gas leaked from the discharge space into the clearance is introduced to the transfer chamber through the guide groove.

Abstract: The invention relates to a gear pump in which the amplitudes of the pressure impulses in a pressure chamber can be significantly reduced by a suitable embodiment of a first groove and/or a second groove. The circumferential walls of a pump chamber containing the pressure chamber, in an angular range extending toward the pressure chamber, each have a respective groove communicating with the pressure chamber, by which grooves a radial spacing between the outer circumference of two gear wheels disposed in the pump chamber and the circumferential walls is increased.

Abstract: The invention relates to a gear pump in which the amplitudes of the pressure impulses in a pressure chamber can be significantly reduced by a suitable embodiment of a first groove and/or a second groove. The circumferential walls of a pump chamber containing the pressure chamber, in an angular range extending toward the pressure chamber, each have a respective groove communicating with the pressure chamber, by which grooves a radial spacing between the outer circumference of two gear wheels disposed in the pump chamber and the circumferential walls is increased.

Abstract: A variable delivery vane pump, in particular for oil, is provided with a stator (10) eccentrically mounted about a rotor (9), which is adapted to turn about one own longitudinal axis (6), and presents a plurality of outwardly radially open grooves (15) and slidingly engaged, each, by a respective vane (17) defined by at least two foils (25) reciprocally overlapped and slidingly coupled one to the other.

Abstract: A method for manufacturing a multi-stage compression type rotary compressor which avoids the replacement of parts to be used as much as possible to reduce costs and also which enables easily setting an appropriate displacement volume ratio between first and second rotary compression elements without increasing the size of the compressor outer housing. This is done by altering the inner diameter of the cylinder of one of the rotary compression elements without altering the thickness (or height) of this cylinder to set a displacement volume ratio between the first and second rotary compression elements to an optimum value in accordance with the alteration.

Abstract: Disclosed is a vane pump capable of decreasing abrasion at a cam surface at the internal surface of a cam ring, pulsation in pump ejected pressure and noise in pump operation. The vane pump is provided with a vane pump section which includes a cam ring rotatably receiving therein a rotor which has a plurality of slits formed radially. Vanes are radially slidably received respectively in the slits to be rotated bodily with the rotor with radial outermost ends sliding on the cam surface. Axial opposite end surfaces of the vane pump section are closed by side wall members, and a backpressure groove which is supplied with the pump ejection pressure in communication with radial innermost end portions of the slits is formed on an inside end surface of each side wall member to encircle the rotational axis of the rotor.

Abstract: A screw machine (10) has a rotor housing (12) defining overlapping bores (13, 15). Female rotor (14) is located in bore (13) and male rotor (16) is located in bore (15). The end faces (24, 26) of the female and male rotors, respectively, have depressions (44, 46, 54, 56, 64) formed in their surface whereby the interface area with the facing surface (51) of the outlet casing (53) is reduced.

Abstract: A crescent pump including a housing having an inlet port and a discharge port, a driving gear, and a driven gear meshing with driving gear in a gap between the inlet and the discharge ports. External and internal troughs on the driving and the driven gears define pump chambers. A stationary crescent-body has a pair of arc-shaped walls which cooperate with the tips of the external and the internal gear teeth thereon in defining fluid seals. The edges of an inlet ramp at an upstream end of the crescent body and the edges of a discharge ramp at a downstream end of the crescent body define inner and outer upstream and downstream metering orifices which close and open in complementary fashion to maintain constant the rate of fluid leakage from the discharge port toward the inlet port. A pair of shaped metering grooves in the pump housing cooperate in defining a flow path between the discharge port and the inlet port through a succession of trapped volumes between the driving and the driven gears.

Abstract: A roller gerotor device is disclosed including an outer rotor (39) and an inner rotor (31), and a plurality of rollers (37) serving as teeth. The device includes a housing means (11,45,47) defining a first wear surface (67) disposed axially adjacent first axial end surfaces (55,63) of the rotors. The first wear surface cooperates with one of the rotors to define an annular fluid passage (83) and a plurality of fluid grooves communicating with the passage (83) and extending radially outward. At least a terminal portion of each of the grooves (87) is adjacent an axial end surface (59) of each roller member (37) as the rotors rotate. Each of the terminal portions (95) becomes progressively shallower in the direction of rotation of the rotors, thus building up fluid pressure in the fluid groove (87) to prevent gouging or galling of the roller end surface against the adjacent wear surface (67).

Abstract: An internal gear pump includes a casing, a cover mounted to the casing, a pump chamber defined between the casing and the cover, an internal gear slidably arranged within the pump chamber, an external gear rotatably arranged within the pump chamber and rotatingly driven from the outside to engage with and drive the internal gear, a fixed filler for regulating sliding movements of the internal and external gears and for preventing oil leakage from a high-pressure side to a lower-pressure side within the pump chamber, a suction port formed in the cover and extended circumferentially within the angular range of about 90 degrees, an oil pocket device formed in respective sliding surfaces of the casing and cover, on which the opposite side surfaces of the internal gear slide, the oil pocket device having a plurality of taper lands extended within the radial width of from the root of tooth of the internal gear to the outer peripheral surface of the internal gear between the peripheral wall of the pump chamber and t

Abstract: A rotary compressor has a plurality of vanes which are slidably disposed in radial slots of a rotor to define fluid chambers in cooperation with a cylindrical housing. The radially innermost end of each vane, rotor and opposite ends of the housing define a back-pressure chamber which is supplied with a pressure during a suction stroke for maintaining the associated vane in sealing contact with the inner wall of the housing. Each of opposite ends of the housing has a unique configuration which damps the pressure in the back-pressure chamber when the chamber is fluidly isolated from a source of the pressure supply during a compression stroke, thereby eliminating excessive friction between the vane and the housing.

Abstract: A compressor includes a rotor with slidable vanes, a cylinder receiving the rotor and vanes and side plates fixed to opposite sides of the cylinder. A suction stream intercepting section is provided in the suction passage between adjacent vane chambers from the supply of refrigerant. The rotary compressor has no loss of refrigeration cooling ability at low speed operation and refrigeration cooling is restrained only at high speed operation.

Abstract: A fluid pressure energy translating device of the sliding vane type comprising a cam ring including an internal contour, a rotor having a plurality of vanes rotatable therewith and slidable relative thereto in slots in the rotor with one end of each vane engaging the internal contour. The rotor and internal contour cooperate to define one or more pumping chambers between the periphery of the rotor and the cam contour through which the vanes pass carrying fluid from an inlet port to an outlet port. At least one cheek plate is associated with the body and rotor. Two pressure chambers are formed for each vane and each vane has two surfaces, one in each chamber, both being effective under pressure in the respective chambers to urge the vanes into engagement with the cam. A generally annular internal feed passage is formed entirely within the rotor and communicates with one set of the pressure chambers.

Abstract: A gear pump (10) is disclosed having a housing (12) defining first and second gear cavities (38,40) and inlet and outlet ports (42,44). A pair of intermeshing gears (20,22) having a plurality of teeth (32) and teeth roots (36) are positioned in the cavities. A pair of bleed slots (50) are provided for directly communicating with the gear tooth roots and permitting entrained air and fluid thereat to be delivered away from the inlet and outlet ports. Advantageously, the bleed slots are located generally adjacent the breakaway points (46) of the respective cavities, and a pair of charging slots (62) are provided for communicating pressure from the outlet port with the gear teeth and encouraging movement of entrained air radially inwardly toward the bleed slots.

Abstract: A hydraulic vane-type pump or motor comprising a housing and a stator defining a rotor chamber, and a rotor for rotation in said chamber on a shaft extending axially through said housing. To prevent gouging of the walls of the rotor chamber by the sharp peripheral edges of the rotor, the rotor sidewalls are ground or offset in the area of the peripheral edges to provide sufficient clearance between the rotor sidewalls and the chamber walls. The rotor is offset to a lesser depth beginning at a point radially inwardly from the outer peripheral edge toward the center thereof to minimize excessive oil leakage normally associated with rotors which are milled to prevent gouging.