A rotary, self-priming, positive displacement pump is described. The pump may include a pump housing including an inlet and an outlet, a pump chamber including an upper wall, a lateral wall, and a floor, first and second rotary impellers in the pump chamber, and a pair of gears each secured to the first and second rotary impellers, and a pressure relief feature operable to relieve pressure developing in a relatively high pressure zone of the pump chamber. The gears mesh with each other to ensure that the vanes do not contact one another during rotation. The pressure relief feature may comprise one or more channels formed in the pump housing and/or the first and second rotary impellers. The channels connect the high pressure zone with another zone to redistribute pressure. The channels may include one continuous channel or alternatively, a plurality of unconnected channels.

A pump assembly comprising at least one housing and two gear wheels. The housing comprises at least one base plate and a cover element, which are interconnectable to form a pressure chamber. An outer circumferential surface of each of the two gear wheels has a toothing, and the gear wheels intermesh via the toothings to convey a fluid. The gear wheels are arranged along an axial direction in the pressure chamber between the base plate and the cover element. The pressure chamber is formed in the housing at least by two bores. The first gear wheel is arranged in a first bore and the second gear wheel is arranged in a second bore. Centering pins are provided for aligning the bores and the gear wheels with respect to one another, wherein all centering pins are arranged exclusively in the cover element or exclusively in the base plate.

A gear for a pump includes a gear body defining a root circle, and a plurality of gear teeth extending from the gear body radially outwardly of the root circle. Each of the plurality of gear teeth have a tip portion, a leading edge, a trailing edge, a circular thickness defined between the leading edge and the trailing edge, a first radially outwardly facing surface and a second radially outwardly facing surface. At least one of the first radially outwardly facing surface and the second radially outwardly facing surface includes a chamfered portion that extends from the leading edge toward the trailing edge across a portion of the circular thickness.

A rotary pump includes a housing featuring a delivery space which the housing surrounds and axially delineates on the end sides; an inner rotor rotatable in the delivery space; an outer rotor rotatable about a pump rotational axis in the delivery space and forming delivery cells with the inner rotor; and a circumferential bearing wall which mounts and surrounds the outer rotor rotatably about the pump rotation axis in radial sliding contact. The circumferential bearing wall includes multiple blind pockets which are radially open towards the outer rotor and/or the outer rotor includes multiple blind pockets which are radially open towards the circumferential bearing wall.

An inner gear includes: sliding surface parts that are provided annularly at an outer peripheral part including a plurality of outer teeth on both sides of the inner gear in its axial direction and that slide on a pump housing; recessed parts that are respectively provided radially inward of the sliding surface parts to respectively form fuel chambers, into which fuel flows, between the recessed parts and the pump housing; and a communication hole that communicates between the recessed parts. The inner gear further includes an inclined surface part that is provided at an edge portion of a communicating edge portion on a rotation advance side of the inner gear, to avoid an adjacent part adjacent to an inner peripheral edge portion of each of the sliding surface parts and that is inclined further toward a rear side in a direction to a central part of the communication hole.

A plurality of external teeth of an inner rotor are formed such that an intake-side clearance is larger than a discharge-side clearance. The intake-side clearance denotes a minimum value of a clearance between an external tooth and an internal tooth defining an inter-teeth chamber which communicates with an intake port and in which an amount of change in volume during rotation of the inner rotor by a unit angle is maximized. The discharge-side clearance denotes a minimum value of a clearance between an external tooth and an internal tooth defining the inter-teeth chamber which at least partially overlaps with a partition wall a first discharge port and a second discharge port when the amount of change in volume per unit angle is maximized.

A gerotor pump is provided with a body defining a chamber with cylindrical wall sections and having a fluid inlet and a fluid outlet, and a cover. An internally toothed gear member is supported for rotation within the chamber about a first axis, and has a cylindrical outer wall defining a series of grooves. Each groove has an associated aperture extending through the gear member to an inner surface of the gear member, and is radially positioned between adjacent teeth of the internally toothed gear member. An externally toothed gear member is rotatably supported within the internally toothed gear member about a second axis spaced apart from the first axis, and is coupled for rotation with a drive shaft. The internally toothed gear member and externally toothed gear member cooperate to form a plurality of variable volume pumping chambers therebetween to pump fluid.

A fluid pumping device is disclosed. The fluid pumping device includes a housing having a front end and a rear end, a fluid discharge opening in the front end of the housing, a pump assembly, a crank assembly rotatably connected to the pump assembly wherein the crank assembly operates the pump assembly, and a fluid storage reservoir connected to the gear housing from which fluid is drawn into the gear housing to be pumped through the fluid discharge opening.

A suction groove is formed in an inside wall surface of a pump cover and is communicated with a suction passage of the pump cover. The suction groove extends along a rotational path of external teeth of an inner rotor and a rotational path of internal teeth of an outer rotor. An edge of a portion of the pump cover, which forms the suction groove, includes chamfered edge parts, which are chamfered, and unchamfered edge parts, which are not chamfered and are not rounded. Each of the unchamfered edge parts is located in a direct-inflow region of the suction groove, which overlaps with the suction passage in a view taken in a direction of a rotational axis, and each of the chamfered edge parts is located in a corresponding one of peripheral regions, which are other than the direct-inflow region.

An inner gear includes an insertion hole, which extends through the inner gear in an axial direction, and a first balance groove, which is axially recessed at an axial end portion of the inner gear and is communicated with the insertion hole. First and second chamfered portions are formed in an inner peripheral edge of the inner gear, which is adjacent to the insertion hole. A joint member has a leg inserted into the insertion hole. An inserting direction of the leg into the insertion hole is defined as a first direction, and a direction, which is opposite from the first direction, is defined as a second direction. In a view taken in a direction perpendicular to the axial direction, at least a part of a first direction side end portion of the leg is axially placed between a first chamfered end plane and a first groove end plane.