Abstract: A gerotor pump arrangement for extracting hydraulic fluid from a transmission housing of a transmission. A first gerotor set has a first inner rotor and a first outer rotor, and a second gerotor set has a second inner rotor and a second outer rotor. The first gerotor set forms a hydraulically drivable drive side of the gerotor pump arrangement, and the second gerotor set forms a pump side, driven by the first gerotor set, wherein the first and second inner rotors are rotationally fixedly mounted on a common shaft which is rotatable about a rotational axis. A transmission with such a gerotor pump arrangement is also disclosed.

Abstract: The invention relates to a scroll pump comprising a pressure sensor integrated into the scroll pump.

Abstract: A toothing for a gerotor pump comprises a plurality of outer teeth (10) at a gerotor inner element (1) and a plurality of inner teeth (20) greater by one at a gerotor outer element (2), wherein a centre (M1) of the gerotor inner element (1) is offset from a centre (M2) of the gerotor outer element (2) by an eccentricity (e), the outer teeth (10) thereby meshing with the inner teeth (20). A contour of the outer teeth (10) at the gerotor inner element (1) is essentially defined by a curve of a single ellipse from a tooth tip (11) continuously via tooth flanks (13) to a transition radius (14) towards a tooth space or a tooth root (12); wherein the principal axis of the ellipse is arranged radially to the gerotor inner element (1) and the centre of the ellipse determines a radius (Rmin) at the gerotor inner element (1) which corresponds to the maximum meshing depth of the gerotor outer element (2) between the outer teeth (10) at the meshing.

Abstract: Embodiments of the present disclosure provide a scroll compressor. The scroll compressor includes: a fixed scroll having an end plate and a fixed scroll wrap extending from the end plate; an orbiting scroll having an orbiting scroll wrap, the orbiting scroll wrap being engaged with the fixed scroll wrap to form a plurality of compression chambers for compressing a medium; a channel formed in the end plate of the fixed scroll, the channel leading to one compression chamber of the plurality of compression chambers; and a valve provided on the end plate of the fixed scroll, and configured to open when a pressure in the one compression chamber is higher than a predetermined pressure threshold so as to allow the medium in the one compression chamber to flow out of the one compression chamber through the channel. The scroll compressor according to the embodiments of the present disclosure, for example, can improve the performance of the scroll compressor.

Abstract: A turbine having a rotor assembly with substantially cylindrical blades. A scoop may be used to direct a fluid flow into the turbine, thereby causing a pushing force and/or a suction force to be exerted on at least some of the cylindrical blades. Accordingly, the rotor assembly may rotate within the turbine. In an example, the rotor assembly may include a plurality of magnets, which may cause a magnetic field to fluctuate. Copper discs on the turbine enclosure may be used to generate electricity based on the changing magnetic field. In another example, the turbine enclosure may have one or more openings, which may generate a suction or pressure force as the rotor assembly rotates.

Abstract: A rotary positive displacement pump for fluids, in particular for the lubrication oil of a motor vehicle engine (60), has a displacement that can be regulated by the rotation of a stator ring (112) having an eccentric cavity (113) in which the rotor (15) of the pump (1) rotates. The stator ring (112) is located in an eccentric cavity (13) of an external ring (12), which is configured as a multistage rotary piston for displacement regulation and is arranged to be directly driven by a fluid under pressure, in particular oil taken from a delivery side (19) of the pump or from a point of the lubrication circuit located downstream of the oil filter (62). A method of regulating the displacement of the pump (1) and a lubrication system for the engine of a motor vehicle in which the pump (1) is used.

Abstract: A vane pump in which oil is drawn from at least one side, in an axial direction, of a cam ring and is discharged from at least the one side, in the axial direction, of the cam ring, the vane pump including: a portion defined by a groove formed on an inner circumference surface of the cam ring, the groove extending along a circumferential direction of the inner circumference surface and arranged in a position including a middle of an axial direction width on the inner circumference surface in an oil suction section or an oil discharge section of the cam ring, the groove being formed so that a depth of the groove is constantly shallower from a mid-point, in the circumferential direction, of the groove to both ends of the groove.

Abstract: A valve device for a hydraulic circuit includes an actuator unit and a valve unit. The actuator unit comprises a spring element and an electromagnetic circuit. The electromagnetic circuit comprises an armature, a core comprising a passage hole, a coil, and a flux-guiding device. A stop element comprising a passage opening is arranged in the passage hole so that a gap exists between the core and the armature when actuating the actuator unit. The valve unit comprises a first opening, a second opening, a third opening formed opposite the actuator unit, a first valve seat between the first and second opening, a second valve seat formed between the first and third opening, a first valve closure body connected to the armature and loaded by the spring element, and a second valve closing body loaded by hydraulic pressure and lifted from the second valve seat by the first valve closure body.

Abstract: The invention relates to a vane cell pump, having a rotor mounted in a pump housing and driven by a shaft, multiple vane plates mounted in this rotor in radially displaceable manner, and an outer ring surrounding the rotor and the vane plates, whereby this ring is disposed either directly in the pump housing or in a setting ring that can be moved in the pump housing along predetermined paths.

Abstract: In one aspect, described is a rotary engine having a purge port located rearwardly of the inlet port and forwardly of the exhaust port along a direction of the revolutions of the rotor, the purge port being in communication with the exhaust port through each of the chambers along a respective portion of each revolution, and the inlet and outlet ports being relatively located such that a volumetric compression ratio of the engine is lower than a volumetric expansion ratio of the engine.

Abstract: A sealing device includes a relatively dimensionally stable, elongated friction and/or wear element and an elastically-deformable elongated sealing element which rests lenghtwise on the friction and/or wear element. The friction and/or wear element encompasses the sealing element at the ends of the friction and/or wear element.

Abstract: A capacity modulation assembly is provided and may include a control valve and a first line extending between the control valve and a suction pressure region disposed within a compressor shell, whereby the suction pressure region is in communication with a suction inlet gas fitting extending through a shell of a compressor. The capacity modulation assembly may additionally include a second line extending between the control valve and an intermediate pressure region disposed within the compressor shell, whereby the intermediate pressure region is in communication with compression pockets defined between an orbiting scroll and a non-orbiting scroll.

Abstract: A downhole drilling motor for well drilling operations includes a tubular housing and a stator disposed in the tubular housing. The stator defines an internal cavity passing therethrough, wherein the stator includes one or more lobes defining at least a portion of the cavity. A rotor is operatively positioned in the internal cavity to cooperate with the one or more lobes of the stator. At least a portion of the stator or of the rotor comprises a memory material adapted to expand or contract when heat is applied by a localized heating module to the memory material. A fluid escape gap between the rotor and stator is adjusted by applying heat to the rotor and/or stator. At least one controller is adapted to receive input data and provide output signals increasing and/or decreasing electrical current applied to the at least one localized heating module.

Abstract: An adjustable vane cell pump is provided having a rotor, which includes, but is not limited to bearing slots extending in radial direction, in which cane plates displaceable relative to the bearing slots are arranged. The vane cell pump further includes, but is not limited to an adjustable slide having a substantially cylindrical inner surface. The rotor is configured in order to driveably rotate about a rotary axis within the slide. The vane plates bear against the inner surface of the slide, and the slide further includes, but is not limited to a first and a second areal end face, as well as recesses, which outer-circumferentially extend parallel to the end faces.

Abstract: A pumping apparatus includes a pump housing, a pumping member which is rotatable in the housing to pump fluid, the pumping member being provided on a support which is in use, driven, the housing including in communication with an inlet, a lower pressure region, and in communication with an outlet, a higher pressure region, there being a passage for fluid from the higher pressure region to the lower pressure region through the support when the fluid pressure in the higher pressure region exceeds a threshold value.

Abstract: A motion-powered liquid sprayer that can increase the number of rotations of the pump relative to each rotation of the wheel or axle is provided. The sprayer can include a gearing assembly that employs gears to increase the number of pump revolutions as a function of the wheel or axle rotation. The sprayer can also include a gear pump that employs an over-capacity or enhanced gullet together with blow-by spacing to control consistent liquid flow relative to variable motional velocities. Further, the sprayer can include a vertically adjustable nozzle as well as a free reverse rotation wheel hub.

Abstract: A sliding vane, positive displacement pump is provided which uses a fixed disc configuration wherein a rotor includes a pair of discs affixed to opposite faces of the rotor so as to rotate with the rotor/shaft. Preferably, the discs each have an outer diameter proximate the outer diameter of the rotor and define an outer disc surface which faces radially outwardly towards an opposing, inside surface of the pump head or other casing structure. A dynamic seal is provided along the outside disc diameter which eliminates the formation of slip between end surfaces. The path of fluid traveling from the high pressure pump side near the outlet to the low pressure side of pump near the inlet is controlled with a radial clearance that is defined between the OD of each disc and the ID of the stationary head.

Abstract: A compressor includes first and second scroll members, a structure supporting the second scroll member, and a first piston. The first scroll member includes a first end plate and a first spiral wrap. The second scroll member includes a second end plate and a second spiral wrap engaged with the first spiral wrap to form compression pockets. The second end plate includes a first aperture in communication with a first compression pocket. The structure includes a first recess and first and second passages. The first piston is axially displaceable between first and second positions within the first recess. The first piston isolates the first passage from communication with the second passage when in the first and second positions, prevents communication between the first aperture and the first passage when in the first position, and provides communication between the first aperture and the first passage when in the second position.

Abstract: A compressor includes first and second scroll members, a piston and a control valve. The first scroll member includes an end plate defining a capacity modulation passage. The first and second scroll members form a suction pocket, an intermediate compression pocket and a discharge pocket. The capacity modulation passage is in communication with the first intermediate compression pocket. The piston is supported on the first scroll member and partially defines a modulation control chamber. The control valve is in communication with the control chamber and selectively provides communication between the control chamber and one of the first and second pressure sources to displace the piston between a closed position and an open position. The piston isolates the capacity modulation passage from communication with the suction pressure region when in the closed position and provides communication between the capacity modulation passage and the suction pressure region when in the open position.

Abstract: A radial piston machine includes a piston having a base which is provided with a roller. The roller is held secure by a bearing shell that is inserted in the piston base.

Abstract: Disclosed is a pump for generating at least two volume flows having a different pressure. Said pump comprises a pump cover, a pump housing, and a wheel set that is eccentrically mounted therein. The pump housing is provided with a suction slot and a pressure slot which are separated from each other by means of a first sealing web and a second sealing sew that is located opposite therefrom. The pressure slot is subdivided into a high pressure chamber and a low pressure chamber with the air of at least one additional sealing web, each pressure chamber being provided with a delivery port.

Abstract: A rotary compressor 100 includes a compression mechanism 3, a motor 2, a suction path 14, a return path 16, a volume varying mechanism 30, an inverter 42, and a controller 44. The return path 16 serves to return a working fluid from the working chamber 25 to the suction path 14. The volume varying mechanism 30 is provided in the return path 16, permits the working fluid to return from the working chamber 25 to the suction path 14 through the return path 16 when the suction volume of the compression mechanism 3 should be set to a relatively small value, and prohibits the working fluid from returning from the working chamber 25 to the suction path 14 through the return path 16 when the suction volume should be set to a relatively large value. The volume varying mechanism 30 and the inverter 42 are controlled so as to compensate for a decrease in the suction volume with an increase in the rotational speed of the motor 2.

Abstract: A variable displacement vane pump having various construction arrangements, including a low pressure supply passage constantly connecting an inlet passage and an other of a first fluid pressure chamber and second fluid pressure chamber; a low pressure introduction port formed in the other of the pump body and the rear body, and opened in an other of the first fluid pressure chamber and the second fluid pressure chamber; and a low pressure introduction passage formed in the other of the pump body and the rear body, the low pressure introduction passage connecting the low pressure introduction port and the inlet ports.

Abstract: The present disclosure relates to a control circuit for a variable displacement pump in a vehicle transmission, including: a regulator valve configured to regulate displacement control fluid to the variable displacement pump; and a response limiter in communication with the regulator valve, configured to mitigate pressure oscillations in the control circuit.

Abstract: A system has a compressor and a consumer which are coupled to a drivetrain and extract energy through the drivetrain. The consumer is suitable for varying an absorption of power, which is made available to it by the drivetrain, as a function of a power which is required for compressor operation and which is supplied from the drivetrain to the compressor. A pump has at least one pump chamber which generates a pumping power during pumping operation. The pump additionally has at least one pump chamber which generates no pumping power or a reduced pumping power during pumping operation.

Abstract: An adjustable vane cell pump is provided having a rotor, which includes, but is not limited to bearing slots extending in radial direction, in which cane plates displaceable relative to the bearing slots are arranged. The vane cell pump further includes, but is not limited to an adjustable slide having a substantially cylindrical inner surface. The rotor is configured in order to driveably rotate about a rotary axis within the slide.

Abstract: An oil pump for an internal combustion engine for drawing up the lubricating oil situated in an oil collector device has an oil pump housing wherein at least two pairs of gears are disposed. The pairs of gears, in order to form the pumping stages, are connected on the suction side to a suction passage formed in the oil pump housing and on the delivery side to a delivery passage. The oil pump housing is further formed with an oil supply passage that is connected to the suction passage of a first pumping stage and via which lubricating oil can be delivered to the suction side of the first pumping stage.

Abstract: A compressor may include a housing and first and second scroll members supported within the housing, each having an end plate with a spiral wrap extending therefrom and meshingly engaged with the other to form a series of compression pockets operating at an intermediate fluid pressure between a suction pressure and a discharge pressure. A first passage in communication with one of the compression pockets extends from a first side of the first end plate to a second side of the first end plate generally opposite the first side. A modulation plate overlies the second side of the first scroll member for radial displacement between first and second positions. The modulation plate isolates the first passage from communication with a suction pressure region of the compressor when in the first position and provides communication between the first passage and the suction pressure region when in the second position.

Abstract: At least one bypass opening is formed in a base of a scroll member, and communicates with at least one compression chamber. The bypass opening communicates with a passage leading to a suction pressure chamber within a compressor shell. A valve includes an element electrically powered to move between a first position at which it blocks flow of refrigerant from the bypass port to the passage leading to the suction pressure chamber, and a second position at which it allows flow of refrigerant between the bypass port and the passage leading to the suction pressure chamber. A portion of the valve, which is electrically powered, is mounted outside of the compressor shell.

Abstract: A pump including a pressure plate having two inlets and outlets, wherein each inlet has an auxiliary intake port in fluid communication with the inlet, and each outlet has an auxiliary discharge port in fluid communication with the outlet, and a cam/rotor assembly attached to the pressure plate. The cam/rotor assembly includes a rotatable cam having an opening, a rotor within the cam opening, the rotor having multiple radial slots, and multiple vanes that move within the slots, wherein a pumping chamber is defined by a space between rotor and cam. Rotor rotation within the cam causes the vanes to extend and retract within the pumping chamber. The movement of the vanes discharges into the outlets and auxiliary discharge ports a fluid drawn into the pumping chamber via inlets and auxiliary intake ports. The auxiliary inlet and auxiliary discharge ports reduce pressure pulsations in a variable displacement dual-lobe vane pump.

Abstract: A variable displacement vane pump includes a pump body, a rotor, an annular cam ring, a rear body closing the pump body, a low pressure supply passage constantly connecting the inlet passage and the other of the first fluid pressure chamber and the second fluid pressure chamber, a low pressure introduction port formed in the other of the pressure plate and the rear body, and opened in the other of the first fluid pressure chamber and the second fluid pressure chamber, and a low pressure introduction passage formed in the other of the pressure plate and the rear body, the low pressure introduction passage connecting the low pressure introduction port and the inlet side vane back pressure grooves.

Abstract: A variable displacement pump including a drive shaft, a cam ring eccentrically moveable with respect to an axis of the drive shaft, and a solenoid drivingly controlled on the basis of variation in electric current amount to be supplied to the solenoid which is controlled in accordance with an operating condition of a vehicle. The solenoid is configured such that a rate of change in the specific discharge amount relative to the electric current amount to be supplied to the solenoid under a condition that the specific discharge amount is smaller is reduced as compared to a rate of change in the specific discharge amount relative to the electric current amount to be supplied to the solenoid under a condition that the specific discharge amount is larger.

Abstract: The present invention is a variable displacement pump system for delivering precisely controlled oil flow and pressure, including a variable displacement pump having an inlet passage, an outlet passage, a first chamber and a second chamber for controlling the displacement of the variable displacement pump. The present invention also includes a fluid control device for receiving fluid from the outlet passage, and selectively delivering fluid to the second chamber. Fluid is delivered from the inlet passage to the outlet passage from the variable displacement pump, and fluid is also delivered from the outlet passage to the first chamber and the fluid control device. When fluid pressure is greater in the first chamber relative to the second chamber, the displacement of the variable displacement pump will decrease, and when fluid pressure is greater in the second chamber relative to the first chamber, the displacement of the variable displacement pump will increase.

Abstract: A blade moves backward/forward to enter four different states, namely a first state in which the tip thereof is in sliding contact with the internal peripheral surface of an external side cylinder part, a second state in which the tip is positioned in the cutaway portion of a ring-shaped piston to thereby place only an external side cylinder chamber at rest, a third state in which the tip is positioned in the cutaway portion of an internal side cylinder part to thereby place only the external side cylinder chamber and an intermediate cylinder chamber at rest, and a whole rest state in which the tip is positioned in a blade groove to thereby place all of the cylinder chambers at rest.

Abstract: A rotary fluid machine, such as a pump or motor has a housing with a spherical interior in which primary and secondary vanes rotate with the secondary vane reciprocating between open and closed positions with respect to the primary vane. Improvements to this type of fluid machine are defined to improve the rigidity of the internals while removing heat generated by compression as well as providing facile conversion of the machine from a liquid pump to a gas compressor, to provide for multiple flow streams at multiple flow rates in a single machine, multiple flow streams at multiple compression ratios in a single machine, and dual simultaneous function as a motor and a compressor.

Abstract: A variable capacity vane pump (100) has a pump housing (10) having a high-load bearing part (10a) on which a higher load is exerted than another part when the pump vane pump (100) operates. A control valve (21) for varying a capacity of the vane pump (100) is provided in a valve housing (28) which is formed integrally in the pump housing (10). By arranging the valve housing (28) on the same side of the pump housing (10) as the high-load bearing part (10a) with respect to the rotation axis of the vane pump (100), the high-load bearing part (10a) can be reinforced without increasing the size of the vane pump (100).

Abstract: Provided is a capacity modulation compressor, comprising: a shell forming a sealed interior space; a compression mechanism, which is positioned inside the shell and modulates a capacity for compressing a working fluid; and an electromotive driving unit, which is positioned inside the shell, includes a stator and a rotor, and drives the compression mechanism; and a shaft for transferring a torque of the electromotive unit to the compression mechanism, the rotor including a rotor core, conductive bars, flux barriers, and permanent magnets, starting running by an induction torque produced due to the presence of the conductive bars, and operating at a synchronous speed by a reluctance torque produced due to the presence of the flux barriers and a magnetic torque produced to the permanent magnets, and the compressing capacity for the compression mechanism to compress the working fluid being set lower than a maximum compression capacity.

Abstract: A scroll compressor has a device which may be actuated to limit the orbit radius of the orbiting scroll. The device is moveable between an unactuated position at which it is spaced from a hub for the scroll compressor, and an actuated position at which it limits the orbit radius of the hub. The device may be actuated when reduced capacity is desired.

Abstract: An oil pump for an internal combustion engine for drawing up the lubricating oil situated in an oil collector device has an oil pump housing wherein at least two pairs of gears are disposed. The pairs of gears, in order to form the pumping stages, are connected on the suction side to a suction passage formed in the oil pump housing and on the delivery side to a delivery passage. The oil pump housing is further formed with an oil supply passage that is connected to the suction passage of a first pumping stage and via which lubricating oil can be delivered to the suction side of the first pumping stage.

Abstract: In a compressor provided with two compression mechanisms of a rotary type compression mechanism and a scroll type compression mechanism, torque fluctuations are reduced. The compressor 1 includes a hermetic housing 2, a low stage-side compression mechanism 3 and a high stage-side compression mechanism 4 provided in the hermetic housing 2; and an electric motor 21 for driving the low stage-side compression mechanism 3 and the high stage-side compression mechanism 4. The low stage-side compression mechanism 3 is a rotary type compression mechanism, and the high stage-side compression mechanism 4 is a scroll type compression mechanism. The suction shutoff of the scroll type compression mechanism is accomplished when a rotor 34 of the rotary type compression mechanism is at a position A corresponding to the bottom dead center, at a position B of being rotated through 90 degrees from the bottom dead center, or between the positions A and B.

Abstract: A vane pump with a reduced rotor diameter is provided. The reduced rotor diameter allows a reduction in the overall size of the pump which allows the pump to be used in circumstances wherein sufficient packaging volume does not exist for conventional vane pumps. Further, the reduced rotor diameter permits operation of the pump at a higher speed, in comparison to conventional vane pumps, for a given working fluid and pump rate. The rotor includes an integrally formed drive shaft and a cylindrical rotor head. Both fixed displacment and variable displacement embodiments are shown.

Abstract: An internal combustion rotary engine is described, adapted to be used both for motor vehicles and ground machines (alternators, compressors, pumps and the like) or water craft or any type. The used fuels are the same of the presently used reciprocating engines. This engine comprises two rotors one inside the other, rotating in the same direction and at the same number of revolutions on two non concentric axes. The eccentricity between the two axes creates a crescent like chamber divided into four parts by four mobile elements mounted on the internal rotor, said elements being in turn constituted by two bodies that fit continuously to the inner surface of the external rotor thus ensuring the tight seal between the chambers. The efficiency of this motor is more than double of a reciprocating engine of the same displacement, with consequent halving of consumptions and emissions of carbon monoxide and dioxide.

Abstract: The disclosed apparatus includes a stator and a rotor disposed for rotation within the stator. An inner wall of the stator defines one or more collider chambers. Rotation of the rotor causes movement of fluid disposed between the rotor and stator and establishes a rotational flow pattern within the collider chambers. The fluid movement induced by the rotor increases the temperature, density, and pressure of the fluid in the collider chamber.

Abstract: A rotary fluid machine, such as a pump or motor, is provided with a fluid flow control mechanism that allows the flow of fluid to be easily and precisely controlled. The device has a housing with a spherical interior in which primary and secondary vanes rotate, with the secondary vane reciprocating between open and closed positions. The primary and secondary vanes define fluid chambers within the housing that communicate with inlet and outlet ports of the device. An adjustable fixed shaft, about which the secondary vane rotates, allows the degree of communication to be varied between the inlet and outlet ports and the chambers formed by the primary and secondary vanes. In this way, the flow rate or fluid capacity of the device, and even the direction of fluid flow, can be changed.

Abstract: A variable capacity rotary compressor includes a housing defining a cylindrical compression chamber therein and having an inlet port and an outlet port communicating with the compression chamber. A rotating shaft is provided with an eccentric part to rotate in the compression chamber. A ring piston is rotatably fitted over the eccentric part such that an outer surface of the ring piston is in contact with an inner surface of the compression chamber. A vane is installed in the housing so as to be in contact with the outer surface of the ring piston and radially reciprocates, and partitions the compression chamber into an intake part and a discharging part. A re-expansion space communicates with the compression chamber, and receives refrigerant therein. A control unit opens or closes an inlet of the re-expansion space to vary a capacity of the rotary compressor.

Abstract: In a variable displacement pump for a power steering device of a vehicle, the adapter ring is arranged to be easily engaged with the engagement hole at the pump casing, to improve ease of assembly. The relationship of the adapter ring with the engagement hole reduces vibration and noise.

Abstract: A rotary fluid machine, such as a pump or motor, is provided with a fluid flow control mechanism that allows the flow of fluid to be easily and precisely controlled. The device has a housing with a spherical interior in which primary and secondary vanes rotate, with the secondary vane reciprocating between open and closed positions. The primary and secondary vanes define fluid chambers within the housing that communicate with inlet and outlet ports of the device. An adjustable fixed shaft, about which the secondary vane rotates, allows the degree of communication to be varied between the inlet and outlet ports and the chambers formed by the primary and secondary vanes. In this way, the flow rate or fluid capacity of the device, and even the direction of fluid flow, can be changed.

Abstract: A rotary fluid machine, such as a pump or motor, is provided with a fluid flow control mechanism that allows the flow of fluid to be easily and precisely controlled. The device has a housing with a spherical interior in which primary and secondary vanes rotate, with the secondary vane reciprocating between open and closed positions. The primary and secondary vanes define fluid chambers within the housing that communicate with inlet and outlet ports of the device. An adjustable fixed shaft, about which the secondary vane rotates, allows the degree of communication to be varied between the inlet and outlet ports and the chambers formed by the primary and secondary vanes. In this way, the flow rate or fluid capacity of the device, and even the direction of fluid flow, can be changed.

Abstract: The invention relates to a vane pump with a rotor which receives vanes, with two pressure plates (17) which bear sealingly on the rotor and of which one is arranged on a delivery side of the vane pump and one on the opposite side, and with a contour ring surrounding the vanes and forming two suction and discharge regions, at least one of the two pressure plates being provided with inlet and outlet orifices (53, 59, 63a, b) which make a fluid connection between a discharge region and an undervane region. The invention is distinguished in that the pressure plate (17.2) located opposite the delivery side has an orifice, which makes a fluid connection between a discharge region and a pressure space (61) partially delimited by this pressure plate (17.2), and seals off the pressure space (61) relative to the other discharge region.

Abstract: Variable-displacement, single-acting vane pumps in which the cylindrical cam member is adjustably supported within an outer annular cam housing to enable the cam member to be adjustably-rotated relative to the housing to adjust the geometric center of the cam chamber relative to the center of the rotor member and thereby adjust the displacement capacity of the pump between zero-flow maximum flow values. The annular housing for the cam member comprises a roller bearing assembly between its inner race surface and the cylindrical outer surface of the cam member, which minimizes the friction when the cam member is rotated during adjustment and enables the adjustment to be actuated remotely, such as by means of a small motor gear assembly.