An oil pump includes: an inner rotor having external teeth; an outer rotor having internal teeth engaging with the external teeth; a housing that houses the inner and outer rotors; a suction port formed in the housing and guiding oil into a pump chamber; a discharge port formed in the housing and guiding the oil to outside the pump chamber; and a discharge passage through which the pump chamber and an outside area communicate with each other and that discharges a bubble in the oil inside the pump chamber to the outside area. A bubble accommodation portion having a recess shape is formed in a side surface portion of each of the external teeth on a side opposite to a rotation direction of the inner rotor.

A fluid gear pump comprising: a first gear including a concentrically disposed first hub portion and a plurality of first teeth; a second gear including a concentrically disposed second hub portion and a plurality of second teeth, wherein at a time in operation the plurality of first teeth and second teeth contact at first and second contact point to create a backlash volume; a first bearing abutting and coaxial to first hub portion; a second bearing abutting and coaxial to second hub portion; and a bridgeland connecting the first and second bearing, the bridgeland separates a low pressure side from a high pressure side, the bridgeland is located such that the backlash volume closes to the high pressure side and opens to the low pressure side when a rate of change of a volume measurement of the backlash volume is decreasing or about equal to zero.

A lightweight gear pump easy to manufacture, having a reduced manufacturing cost, while giving sufficient performances. It consists of: A gear, three metal plates, placed on each other, an intermediate plate of which including an eight-shaped cavity adapted to house the gear, and two peripheral plates having the function of enclosing the gear in the cavity, a circuit for fluid supply to the gear, centering means to align the three plates above each other, the three metal plates being provided with centering holes in the axial direction, adapted to receive the centering means, the device according to the invention is particularly intended for liquid transfer applications for automobiles or heavy trucks.

A pump includes first and second gears coupled to one-another for rotation about respective axis. The first gear may include a concentrically disposed first hub portion and a plurality of first teeth radially projecting and circumferentially spaced about the first hub portion. A plurality of first recesses are defined by the first hub portion, communicate radially outward, and are circumferentially distributed about the first hub portion between adjacent teeth of the plurality of first teeth.

An oil pump includes: a pump housing having a rotor accommodation space in an inner portion of the pump housing; a rotor accommodated in the rotor accommodation space; a shaft portion disposed inside the rotor; and a passage which is provided to straddle at least one of the pump housing and the rotor and the shaft portion and which communicates a pump chamber which is formed by the rotor inside the pump housing with an outside of the pump housing.

A gear pump can include at least one gear having a plurality of gear teeth. At least the plurality of gear teeth can be additively manufactured and can include a substrate and a pitting resistant outer coating additively manufactured on the substrate and configured to prevent pitting due to cavitation. The substrate can include a substrate material and the pitting resistant outer coating includes a pitting resistant material different than the substrate material. The pitting resistant outer coating defines an outer surface layer of the gear teeth.

A gerotor assembly is provided which includes a crankshaft, an inner drive gear, an outer driven gear and a housing defining an oil groove. The inner drive gear defines a plurality of inner gear teeth. The outer driven gear defines a plurality of outer gear teeth operatively configured to engage with the inner gear teeth. The outer drive gear may define a plurality of passageways to form a hydrodynamic film between the outer driven gear and the housing. Alternatively, a high pressure oil pump may feed oil into the oil groove in order to distribute a hydrodynamic film.

A gear pump includes a drive gear with drive gear teeth and a driven gear with driven gear teeth. The drive gear is rotatably disposed about a drive gear axis. The driven gear is rotatably disposed about a driven gear axis and is intermeshed with the drive gear such that a plurality of driven gear teeth are in sliding contact with a plurality of the driven gear teeth. One or more of the drive gear teeth or the driven gear teeth define within the tooth interior a cavity. The cavity is in fluid communication through an orifice with an inter-tooth volume defined between the contacting drive gear teeth and driven gear teeth such that fluid flows through the orifice to reduce cavitation within fluid confined within the inter-tooth volume.

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.

An oil pump includes: an inner rotor including external teeth; an outer rotor including internal teeth; a housing configured to accommodate the inner and outer rotors; an inlet port formed in the housing and configured to guide oil into a pump chamber between the external and internal teeth; an outlet port formed in the housing and configured to guide the oil to the outside of the pump chamber; and a discharge hole formed in the housing and configured to guide bubbles in the oil to the outside of the pump chamber. The discharge hole communicates with the pump chamber earlier than a timing when the pump chamber and the outlet port communicate with each other. The outlet port communicates with the pump chamber later than a timing when the pump chamber has a maximum volume.