Abstract: An engine is disclosed. According to one embodiment of the present invention, the engine comprises a compressor, and combustor, and an expander. The compressor compresses ambient air. The combustor burns the compressed air, and produces exhaust gasses. The expander receives the exhaust gases from the combustor, and expands the exhaust gasses. The compressor may be a gerotor compressor or a piston compressor having variable-dead-volume control. The expander may be a gerotor expander or a piston expander having variable-dead-volume control. In another embodiment, an engine comprises a piston compressor, a combustor, a piston expander, and a pressure tank. The piston compressor compresses ambient air. The combustor bums the compressed air, and produces exhaust gasses. The piston expander receives the exhaust gasses from the combustor, and expands the exhaust gasses. The pressure tank receives and stores the compressed air from the compressor.

Abstract: A housing for a micro pump or like micro system has at least three structured elements which are layered and which respectively form a support plate, a connecting block and a base element with a further plate-shaped layered structure element located between the connecting block and the support plate and serving with the axially oriented or circumferentially-oriented channel section for conveying fluid between the connecting block and the support plate.

Abstract: In a rotary pump in which axial end surfaces of outer and inner rotors is in pressurized direct contact with an axial end surface of a second side plate to form a mechanical sealing, both of the axial end surfaces of the outer and inner rotors and the axial end surface of the second side plate are provided with radial line grinding stripes. Teeth gap portions formed by the outer and inner rotors in mesh communicate with an outer circumference gap between the circumference of the outer rotor and inner circumference of a center plate and also with a shaft hole of the inner rotor through extremely slight gaps formed by concave and convex of the radial line grinding stripes so that contact surface between the outer and inner rotors and the second side plate is well lubricated to reduce torque loss.

Abstract: Two-inner gears are overlapped with each other through a partition wall and are eccentrically arranged at an inner peripheral side of an outer gear, and eccentric directions of both the inner gears are shifted from each other by 180° to the opposite side. By this, loads in an outer diameter direction due to a rise in fuel pressure affect one outer gear from the two inner gears oppositely to each other by 180°, so that an eccentric load is not generated, and sliding resistance of the outer gear to a cylindrical casing becomes small. Further, the number of teeth of the outer gear is made odd, and the number of teeth of the inner gears is made even.

Abstract: An improved hydraulic motor system, suitable for driving an automotive cooling fan or the like. The system is driven by grade gerotor set and an idle gerotor set which are stacked between a center plate and against a rear wall of a cylindrical cavity in a front face of a manifold. A fluid-tight chamber is established by securing an end frame can around the stacked gerotor sets and against the perimeter of the manifold cavity. Tightness of the seal is controlled by positioning a resilient cover plate against the end frame can from a position opposite the manifold, and adjustably clamping the resilient cover against the manifold until the resilient cover has undergone a predetermined amount of elastic deformation.

Abstract: The invention concerns a tooth set for a hydraulic machine, particularly a steering unit, with a toothed ring, having teeth, which are formed by means of inserts arranged in a housing, and a gear wheel arranged inside the toothed ring. It is endeavoured to simplify the production of such a tooth set. For this purpose, each inset (10) has, at least at its ends, a plate-like shape and the ends are fixed in the housing (11) in corresponding slots (17, 18).

Abstract: The invention concerns a tooth set (1) for a hydraulic machine (2), particularly a hydraulic steering unit, with a toothed ring (3), a gear wheel (4) arranged inside the toothed ring (3), a first plate (7) on an axial front side of the gear wheel (4) and the toothed ring (3) and a second plate (5) on the other axial front side. A simplification of the production is endeavoured. For this purpose, the two plates (5, 7) and the parts between them, gear wheel (4) and toothed ring (3), can be handled as a self-retainingly assembled module (1).

Abstract: Two inner gears are overlapped with each other through a partition wall and are eccentrically arranged at an inner peripheral side of an outer gear, and eccentric directions of both the inner gears are shifted from each other by 180° to the opposite side. By this, loads in an outer diameter direction due to a rise in fuel pressure affect one outer gear from the two inner gears oppositely to each other by 180°, so that an eccentric load is not generated, and sliding resistance of the outer gear to a cylindrical casing becomes small. Further, the number of teeth of the outer gear is made odd, and the number of teeth of the inner gears is made even.

Abstract: In the brake apparatus having a rotary pump, outer and inner rotors of the rotary pump are made of bearing steel and inner and outer teeth portions of the rotors are respectively processed by nitriding hardening or carbo-nitriding hardening. Accordingly, outer circumferential region of the outer teeth portion and inner circumferential region of the inner teeth are constituted by nitrided layer containing 15 to 40 percents retained austenite so that teeth faces of the outer and inner teeth portions in mesh may have higher wear resistance.

Abstract: In a rotary pump, an outer rotor and an inner rotor are assembled in a casing such that, when a clearance between an inner teeth portion of the outer rotor and an outer teeth portion of the inner rotor is substantially nullified at a first closed gap portion having a maximum volume formed between the inner teeth portion and the outer teeth portion, a clearance between the outer rotor and the casing on a side of the first closed gap portion and a clearance between the outer rotor and the casing on a side of a second closed gap portion having a minimum volume, become substantially an equivalent interval. As a result, the outer rotor and the casing can be brought into contact with each other on the side of the second closed gap portion rather than the central axis of the inner rotor. Even in a high pressure discharge operation, the outer rotor is not locked by being squeezed between the inner rotor and the casing.

Abstract: A two-dimensional rotary displacement device comprises a housing, an outer rotor and at least one inner rotor. The axes of rotation of the outer rotor and the at least one inner rotor are parallel. A predefined geometrical relationship exists between the outer and inner rotors such that the scale of operative circumference (or diameter) from the inner rotor with respect to the outer rotor is preferably an integer value. In one embodiment, the device is used as a compressor that positively displaces a gas. In a modified embodiment, the device includes an exit port, which has a location that can be adjusted with respect to the housing and is adjustable so as to decrease the pressure differential between an exit chamber and the exit pressure.

Abstract: A trochoid pump composed of an inner gear and an outer gear is used as a fluid pump such as a fuel pump for an automotive vehicle. An inner imbalance load inherently developing in the pumping chambers is suppressed or canceled by an outer imbalance load generated by pressurizing fluid introduced into blade ditches formed on an outer periphery of the outer gear. Positions of a pressure-introducing port and a pressure-releasing port for the blade ditches are selected so that the outer imbalance load is imposed in a direction opposing the inner imbalance load. An amount of the outer imbalance load is made equal to an amount of the inner imbalance load to eliminate undesirable effects of the inner imbalance load.

Abstract: An internal gear pump has a housing, a toothed ring provided with inner teeth, a bearing ring supporting the toothed ring in the housing rotatably about a rotary axis, a toothed gear provided with outer teeth and engaging with the toothed ring, the toothed gear being rotatable in the housing about a rotary axis, the toothed gear or the toothed ring being rotatably driven, the rotary axis of the toothed ring being offset relative to the rotary axis of the toothed gear, and an adjusting device associated with the bearing ring for moving the bearing ring in a radial direction relative to the rotary axis of the toothed ring in the housing for an adjustment and for blocking it in an adjusted position.

Abstract: A positive displacement rotary pump including a housing having an internal chamber and inlet and discharge ports, a sealing land on the housing between a downstream end of the inlet port and an upstream end of the discharge port, and a rotating group in the internal chamber defining a plurality of pump chambers. The pump chambers traverse in succession and at regular intervals the inlet port and the sealing land and the discharge port. The housing has a stationary pre-charging passage which communicates with the discharge port and overlaps the sealing land. The rotating group includes a plurality of rotating pre-charging passages which communicate with respective ones of the pump chambers.

Abstract: A pump has meshing inner and outer rotors mounted eccentrically in a housing. The pump also has an inlet and a main outlet. The main outlet communicates via a control gap with a secondary outlet. The control gap provides a filtering action for some of the fluid pumped.

Abstract: An oil pump that can be reduced in weight and is excellent in wear resistance and easy to manufacture is provided. The oil pump includes an oil pump housing formed of aluminum alloy, and an inner rotor and an outer rotor that slide along the oil pump housing with contact kept therebetween to suck and discharge oil. Composite layers including porous metallic bodies are arranged at parts of the oil pump housing that contact the inner rotor and the outer rotor. Pores of the porous metallic bodies are impregnated with the aluminum alloy constituting the oil pump housing.

Abstract: The invention is related to a pump, preferably a positive-displacement pump, comprising:

Abstract: A drive system is provided for coupling a clutch assembly with a pump assembly that provides fluid power to cool, lubricate and control the operation of the clutch. The drive system comprises a drive coupling rotatably supported on an input shaft by a plurality of bearing members. The bearing members permit the drive coupling to rotate independent of the rotation of the input shaft. The drive coupling is provided with at least two splined surfaces for engaging a corresponding splined surface on both the clutch assembly and the pump. The drive system counteracts radial loads generated within the pump and moment loads generated at the splined connections to prevent premature wear or damage to the pumping elements and mating components.

Abstract: In a shaft (19) having outer teeth (18) for transferring torque between hydraulic machines (1, 2) arranged coaxially behind one another, especially hydraulic pumps of a steering device, in which an inner wheel (7; 8) provided with teeth (9; 10; 15; 16) on the inside and outside moves around the inside of a toothed ring (3; 4) having inner teeth (5; 6) and engages with the teeth (5; 6) of the toothed ring (3; 4), and the teeth (18) of the shaft (19) engage without relative rotation in the inner teeth (15; 16) of the inner wheels (7, 8), in order to simplify manufacture and assembly of the shaft and to avoid noise, the thickness of the teeth (18) of the shaft (19) or of the inner teeth (15; 16) of the inner wheels (7, 8), measured on the reference circle, is greater than the width, measured on the reference circle, of the gaps into which those teeth (18; 7; 8) engage, with the result that the flanks of the teeth (18) of the shaft (19) come into contact securely with the flanks of the inner teeth (15; 16) of the

Abstract: A dual gerotor pump is used for an automatic transmission. A dual gerotor pump which is driven by a central drive mechanism has a first chamber which continuously provides transmission fluid to the automatic transmission. The pump also has a second pumping chamber which selectively directs fluid to the automatic transmission when necessary. A valve mechanism is provided to divert fluid from the second pumping chamber back to the second pumping chamber so that it can recirculate thereby decreasing fluid pressure to the automatic transmission when it is not required.

Abstract: An oil pump includes suction and discharge chambers formed in a sidewall of a housing, and a maximum-volume-side partition area formed with the sidewall of the housing on a trajectory of pump houses and at a position where each pump house has a maximum volume, wherein the maximum-volume-side partition area creates a section where any pump house spreads over neither of the suction and discharge chambers. A plurality of channels is arranged in the discharge chamber at an end thereof, each channel having a predetermined length and extending to the maximum-volume-side partition area.

Abstract: An internal gear oil pump made of Al alloys having less mutual damage property and superior wear resistance is provided. The internal gear oil pump has a casing with a gear compartment, a drive gear, and a driven gear, all of which are the structural members of the internal gear oil pump. The casing is constituted of an Al-alloy casting. The drive gear and the driven gear are constituted of a hot plastic working material of Al—Si alloy powder. The hot plastic working material is constituted of an Al—Si alloy having a structure in which unit crystal phases are dispersed in a base matrix by 10 to 40 area percent. by the structural observation with an optical microscope, the unit. crystal phases being harder than the base matrix. The base matrix is constituted of an Al—Si alloy which contains, on weight basis, 10% to 18% Si, 4% to 8% Fe, 1% to 3% Ni, 1% to 3% Cr, and the balance being Al and incidental impurities.

Abstract: This invention is directed to a pump bracket that is adapted to allow for the inboard or outboard mounting of a mechanical seal or packing material to accommodate different pump configurations and applications. The universal pump bracket includes a first flange that is adapted to be connected to a pump housing and a second flange, which is laterally displaced from the first flange and adapted to be connected to a bearing carrier. If an inboard mechanical seal or inboard packing arrangement is desired, the bracket can be installed so the seal is facing the inboard direction. Alternatively, if an outboard seal arrangement is desired, the bracket can be installed on the rotor so the seal or packing faces the outboard direction.

Abstract: An oil pump apparatus includes an oil pump housing having a first suction port a second suction port and a discharge port in the circumferential direction thereof. A shape of the end portion in the anti-rotational direction at the second suction port is formed so as to be along a shape of the end portion in the rotational direction at the pump chamber which is sealed momentarily between the first suction port and the second suction port, and a shape of the inner circumferential end portion of the first suction port is formed so as to be along the rotational trace of the end portion on the side of the anti-rotational direction at the pump chamber which is sealed momentarily between the first suction port and the second suction port. A plural first pockets are formed on the driven rotor, and a second pocket is formed on the pump housing.

Abstract: An engine is disclosed. According to one embodiment of the present invention, the engine comprises a compressor, and combustor, and an expander. The compressor compresses ambient air. The combustor bums the compressed air, and produces exhaust gasses. The expander receives the exhaust gases from the combustor, and expands the exhaust gasses. The compressor may be a gerotor compressor or a piston compressor having variable-dead-volume control. The expander may be a gerotor expander or a piston expander having variable-dead-volume control. In another embodiment, an engine comprises a piston compressor, a combustor, a piston expander, and a pressure tank. The piston compressor compresses ambient air. The combustor bums the compressed air, and produces exhaust gasses. The piston expander receives the exhaust gasses from the combustor, and expands the exhaust gasses. The pressure tank receives and stores the compressed air from the compressor.

Abstract: The invention concerns a micropump for the substantially continuous delivery of a mass flow, the micropump having a sleeve axis and an offset axis of rotation. An internal rotor meshes with an external rotor in a sleeve and at least one outlet-side pressure opening in a first end-face termination part. Both rotors have a dimension smaller than 10 mm. The invention further concerns a micromotor of similar construction in which the diameter of rotors and the casing are below 10 mm. The pump and motor are extremely miniaturized yet still permit a continuous flow with high feed pressure and high output.

Abstract: A gerotor assembly includes a pressure chamber with an integral eccentric ring for a motor vehicle hydraulic differential for use in hydraulic limited slip differentials for axles, transfer case center differentials and similar devices. The gerotor pump assembly in accordance with the present invention includes a housing having an integral ring which provides a pressure chamber for a piston, an eccentrically positioned recess for a inner rotor and an outer rotor and a location for a pressure limiting system. The gerotor pump assembly is of a non-reversing gerotor pump configuration using known methods to produce a unidirectional fluid flow.

Abstract: An engine is disclosed. According to one embodiment of the present invention, the engine comprises a compressor, and combustor, and an expander. The compressor compresses ambient air. The combustor burns the compressed air, and produces exhaust gasses. The expander receives the exhaust gases from the combustor, and expands the exhaust gasses. The compressor may be a gerotor compressor or a piston compressor having variable-dead-volume control. The expander may be a gerotor expander or a piston expander having variable-dead-volume control. In another embodiment, an engine comprises a piston compressor, a combustor, a piston expander, and a pressure tank. The piston compressor compresses ambient air. The combustor burns the compressed air, and produces exhaust gasses. The piston expander receives the exhaust gasses from the combustor, and expands the exhaust gasses. The pressure tank receives and stores the compressed air from the compressor.

Abstract: Two inner gears are overlapped with each other through a partition wall and are eccentrically arranged at an inner peripheral side of an outer gear, and eccentric directions of both the inner gears are shifted from each other by 180° to the opposite side. By this, loads in an outer diameter direction due to a rise in fuel pressure affect one outer gear from the two inner gears oppositely to each other by 180°, so that an eccentric load is not generated, and sliding resistance of the outer gear to a cylindrical casing becomes small. Further, the number of teeth of the outer gear is made odd, and the number of teeth of the inner gears is made even.

Abstract: A gear pump has a gear wheel with teeth on an outer circumference and a second gear ring with teeth on the inside surface. The gear ring is guided in a circular-cylindrical recess of a housing and together with the gear wheel, each rotates about their own axis which are offset from one another. The gear pump is equipped with an intake opening and a crescent-shaped pressure opening in a first side wall of the housing that defines the recess. A countersunk feature is also provided, embodied as a hollow cone, in a second wall of the housing opposite the pressure opening. The hollow cone, which is in fluid communication with the pressure opening, promotes the buildup of a fluid film between the gear ring and the housing, which improves the wear resistance of the gear pump.

Abstract: An oil pump that can be reduced in weight and is excellent in wear resistance and easy to manufacture is provided. The oil pump includes an oil pump housing formed of aluminum alloy, and an inner rotor and an outer rotor that slide along the oil pump housing with contact kept therebetween to suck and discharge oil. Composite layers including porous metallic bodies are arranged at parts of the oil pump housing that contact the inner rotor and the outer rotor. Pores of the porous metallic bodies are impregnated with the aluminum alloy constituting the oil pump housing.

Abstract: In the rotary pump, a sealing member is provided at a clearance between a casing and axial end surfaces of the inner and outer rotors, the sealing member extending from an outer circumference of the outer rotor, via the inner rotor between a drive shaft and a discharge port, to another circumference of the outer rotor so that brake fluid communication from the discharge port to an intake port may be prevented, but the brake fluid communication between the outer circumference of the outer rotor and almost all of teeth gap portions on a discharge port side and, further, between almost all of teeth gap portions on an intake port side and a clearance between the drive shaft and the inner rotor may be allowed.

Abstract: In a pump equipment having plural rotary pumps, the respective discharge ports of the rotary pumps are located at the points which are nearly symmetrical with respect to the center axis of the drive shaft to counterbalance each other the respective reaction forces against the drive shaft to be produced by the high pressure at the respective discharge ports. The respective discharge fluid conduits, in case of the first and second pumps, are located at the points which are opposite each other, more preferably, different at an angle of 180 degrees each other, with respect to the center axis of the drive shaft to limit the bending of the drive shaft. As a method for assembling the pump equipment, the peripheral border between respective cylindrical members piled up for constituting the casing is tentatively welded by laser beam at first and, then, all around the peripheral borders are finally welded.

Abstract: A positive displacement hydraulic unit includes a housing having a chamber formed therein with a circumferential surface bounded by a pair of spaced apart end walls. A rotary element for displacing fluid rotatably mounts in the chamber. A layer of abradable coating material is positioned between an end wall of the chamber and the adjacent side wall of the rotary element so as to provide a near-zero side clearance for the rotary element and thereby high volumetric efficiency for the hydraulic unit.

Abstract: The pump has a fixed gear axis eccentricity and varies displacement by moving controlling elements linearly along the drive shaft. A pressure compensator may be employed to displace the controlling elements. The pump includes a housing penetrated by a drive shaft rotating internal elements. The internal components slide along the longitudinal axis established by the drive shaft to vary the fluid displacement of the pump. The axially-moving elements include the drive shaft, inner gerotor element, port plug, thrust bearing and retainer sleeve. The drive shaft includes an internal flanged forming a piston. The outward face of the piston is in contact with fluid at system pressure. The internal gerotor element and port plug are retained against the piston by a thrust bearing that slides over the drive shaft and is held in place by a retainer sleeve. The port plug has a rear face that also functions as a piston and this face is the same size as the flanged piston.

Abstract: An internal gear pump which improves the mechanical efficiency and the life and reduces noises by eliminating non-uniformity of the gaps between teeth. In the internal gear pump wherein the tooth spaces of the outer gear and the tooth tips of the inner gear form an epicycloid and the tooth tips of the outer gear and the tooth spaces of the inner gear form a hypocycloid, these cycloids are formed by four circles that roll on the pitch circle of each gear such that the gap between teeth in a region where the outer and inner gears mesh most deeply with each other is substantially equal to the gap between teeth in a region where the depth of mesh between the outer and inner gears are the shallowest.

Abstract: There is disclosed a hydraulic or pneumatic machine having a first displacement element (8) that is rotatable about an axis of rotation connected to a shaft (10) so as to rotate therewith, which shaft is mounted rotatably in a housing (2), and co-operates with a second displacement element (9). The structure of such a machine is to be improved. For that purpose, the housing (2) has a pocket (3) in which the displacement elements (8, 9) are so arranged that the housing (2) covers the displacement elements (8, 9) axially on both sides (4, 5) at least in a working region and in the circumferential direction over a maximum of 180°.

Abstract: A hydraulic machine of the gerotor type. The machine uses two gerotors which are preferably coplanar, and positioned nearly concentric to each other. This dual arrangement approximately doubles the displacement of hydraulic fluid per revolution, compared with a single gerotor, and thus doubles power transfer. Yet the housing containing the gerotors need only be large enough to contain the larger gerotor.

Abstract: An internal-gear machine has a casing and a running assembly accommodated in the casing and comprising a rotatably mounted pinion and an internally toothed annular gear meshing with the pinion. The annular gear is widened at its outer periphery to form a running ring which can be integral with the internally toothed part of the annular gear or a separately produced component which is non-rotatably connected to the internally toothed part.

Abstract: An oil pump drive assembly for an internal combustion engine includes a source of rotational input such as a crankshaft and a splined hub mounted to the crankshaft for rotation therewith. The splined hub has male splines extending about the outer perimeter to transfer rotational load to drive an oil pump. The oil pump includes a pump body housing a gerotor pump set, which includes an internally lobed pumping annulus and a pump rotor. The pump rotor has lobes along the outer surface to engage the internally lobed pumping annulus and female splines along the inner surface which compliment and receive the male splines of the splined hub for meshing engagement to operatively connect the crankshaft and the gerotor pump set.

Abstract: The invention concerns a micropump for the substantially continuous delivery of a mass flow, the micropump having a sleeve axis and an offset axis of rotation. An internal rotor meshes with an external rotor in a sleeve and at least one outlet-side pressure opening in a first end-face insert part which is inserted into the sleeve of slightly largely diameter, is aligned in the axial direction. The invention further concerns a micromotor of similar construction in which the diameter of the delivery hose corresponds approximately to that of the sleeve casing. The pump and motor are extremely miniaturized yet still permit a continuous flow with high feed pressure and high output.

Abstract: A trochoidal gear pump or engine uses a coaxial hub with the outer and/or inner rotor and an associated rolling element bearing assembly that preferably uses pre-loaded bearings to precisely set the rotational axis and/or the axial position of the rotor with which it is associated. This allows the fixed-gap clearance between the rotor surfaces and the housing surfaces or the other rotor surfaces to be set at a distance that minimizes operating fluid shear forces and/or by-pass leakage and eliminates gear tooth wear thus preserving effective chamber to chamber sealing. The device is useful in handling gaseous and two-phase fluids in expansion/contracting fluid engines/compressors and can incorporate an output shaft that accommodates an integrated condensate pump for use with Rankine cycles. A vent from the housing cavity to a lower pressure input or output port regulates built-up fluid pressure in the housing thereby optimizing the efficiency of the device by controlling bypass leakage.

Abstract: This invention relates to an oil pump apparatus which comprises an oil pump housing, a rotor rotatably located in the oil pump housing, the rotor forming a first set of pockets having a capacity increasing toward a rotating direction of the rotor and a second set of pockets having a capacity decreasing toward the rotating direction of the rotor, a plurality of suction ports connected with the first set of pockets, each of the suction ports being isolated from other adjacent suction ports, a discharge port connected with the second set of the pockets, and a control valve which includes a valve member, an urging member for urging the valve member and an urging member's chamber for disposing the urging member, the control valve being operatively positioned to control fluid flow through the plurality of the suction ports and the discharge port, and the control valve is operatively connected to select between a first condition in which the control valve connects with the suction ports and a second condition i

Abstract: A pump gear for an automatic transmission oil pump having a plurality of teeth. The thickness of each tooth varies randomly from a baseline thickness T.sub.B. Correspondingly, the clearance between each tooth varies randomly between each pair of adjacent teeth. The random variation in tooth thickness prevents the formation of resonant frequencies when the gear pump operates, thereby reducing noise produced by the automatic transmission oil pump.

Abstract: The invention concerns a hydraulic motor (1) having at least one gearwheel set section (2), a supply section (3) and a front section (4) on which an output arrangement (15) can be fixed, the sections (2 to 4) being connected with each other in the axial direction by fixing bolts (11).It is desired to simplify the production and the service during operation for such a motor.For this purpose several bores (17) are provided, which penetrate the motor (1,) from one axial end (21) to the other, in which connection bolts (6) are arranged, which are provided with an engagement area (18) on the side of the front section (4).

Abstract: An internal gear pump includes in a pump housing an outer rotor including an internal gear portion on the inner periphery, and an inner rotor being eccentrically disposed with respect to the outer rotor and including an external gear portion on the outer periphery that is engaged with the internal gear portion of the outer rotor. A side plate is integrated with the outer rotor to abut on a side of the inner rotor that fails to be in slide contact with the housing. A holding device is mounted to the pump housing to restrict a position of the outer rotor with respect to the housing.

Abstract: An oil pump apparatus incorporates a housing defining therein a generally cylindrical space, an outer rotor having a substantially cylindrical outer peripheral surface disposed in rotatably sliding contact with an inner peripheral surface of the cylindrical space, the outer rotor further having an inner peripheral surface formed thereon with a plurality of circumferentially equally spaced gear teeth, and a shaft rotatably mounted in the housing.

Abstract: A gerotor pump includes a pressure relief return flow guide system, composed of two distinct structures, a pressure relief port, and a flow guide. The pressure relief port separates the pressure relief flow and inlet flow, preventing them from mixing and causing turbulence in the inlet cavities. The flow guide is located at the end of the pressure relief port and the inlet to make the two flows smoothly merge in the inlet cavities.

Abstract: An electric motor fuel pump has an inner gear rotor and an outer gear rotor each with a plurality of radially opposed intermeshing teeth each having a pair of driving surfaces and defining circumferentially disposed expanding and ensmalling pumping chambers through which fuel is drawn and then discharged under pressure. The inner gear rotor is coupled to a motor armature journalled for rotation within a fuel pump housing to drive the inner gear rotor and the associated outer gear rotor. The teeth of each gear rotor have a step formed thereon providing a pair of offset driving surfaces on at least each driving face of each tooth and preferably offset trailing surfaces on each trailing face of each tooth. The stepped tooth profile permits greater eccentricity between inner and outer gear rotors which increases the fuel displacement of the gear rotors.

Abstract: A positive displacement gear rotor fuel pump with a plurality of spaced apart outlet ports through which fuel is discharged from a fuel pumping assembly and a valve which prevents any fuel downstream of the outlet ports which is at outlet pressure, from reentering portions of the pumping assembly which are at a lower pressure to prevent the higher pressure fuel from rapidly compressing and collapsing the fuel vapor in the pumping assembly to greatly reduce the noise of the operating fuel pump. This reduces the magnitude of the cavitation noise in the fuel pump which is the noise caused by the collapsing of the fuel vapor in the pump. The outlet ports are also constructed and arranged to prevent adjacent pumping chambers of the pumping assembly from communicating with each other to prevent the fuel at an increased pressure in a downstream pumping chamber from flowing into a lower pressure pumping chamber upstream thereof to also reduce cavitation noise in the fuel pump.