A pump includes: a housing in which a pump chamber that is a columnar space is formed, the pump chamber being provided with a suction-side groove and a discharge-side groove that are formed as recesses; an outer rotor rotatably disposed in the pump chamber and having internal teeth on an inner periphery of the outer rotor; and an inner rotor disposed radially inward of the internal teeth of the outer rotor, and having external teeth formed on an outer periphery of the inner rotor and meshed with the internal teeth of the outer rotor. A portion of an inner edge of the discharge-side groove is located radially inward of a locus of tooth tips of the internal teeth of the outer rotor, the portion being located in a second half region of the discharge-side groove in a rotational direction of the inner rotor and the outer rotor.

An internal gear pump includes an outer rotor having internal teeth, an inner rotor rotatably disposed inside the outer rotor and having external teeth engaging with the internal teeth, and a pump housing. The pump housing includes: a holding recess rotatably holding the outer rotor and having a wall on which an outer peripheral face of the outer rotor is to slide; an inlet to take in a fluid into pump chambers defined between the inner rotor and the outer rotor; an outlet to discharge the fluid from the pump chambers; a case groove provided on the wall and to hold the fluid; and a joint groove provided on an upper land face defined between a trailing end of the inlet and a leading end of the outlet and on which the internal teeth and the external teeth are to slide.

A gerotor pump includes a casing including a pumping chamber, a fixed gear being inserted into the casing and rotating at a fixed position, including a plurality of teeth formed inside a cylinder, and including at least one fluid hole at one end of the cylinder to allow a fluid to flow from the pumping chamber or into the pumping chamber, a moving gear provided inside the fixed gear and including one less number of teeth than a number of the plurality of teeth of the fixed gear and movable in an axial direction, a gear block arranged inside the fixed gear and movable in the axial direction, a gear ring arranged outside the moving gear, in which the moving gear can be movable with respect to the gear ring in the axial direction, and a gear ring cover provided at one end of the casing and including a hole in which the gear ring is rotated.

One example of a gerotor pump includes an inner rotor comprising multiple teeth, the inner rotor configured to rotate about a first longitudinal gerotor pump axis. The gerotor pump also includes a hollow outer rotor including an outer surface and an inner surface having substantially identical contours, the inner surface configured to engage with the multiple teeth and to rotate about a second longitudinal gerotor pump axis. The pump includes a pump housing within which the inner rotor and the outer rotor are disposed, wherein the outer surface of the outer rotor defines gaps between the pump housing and the outer rotor.

A pump device includes a housing, a pump element, and an on-off valve. The housing includes a suction passage defining a suction port at an upstream end, a discharge passage defining a discharge port at a downstream end, and a return passage returning a part of a fluid flowing through the discharge passage to midway of the suction passage. The pump element is accommodated in the housing and rotates around a predetermined axis to suck, pressurize, and discharge a fluid. The on-off valve opens and closes the return passage. In the suction passage upstream of an opening at which the return passage is opened to the suction passage, the housing includes a directional wall which directs a flow of a suction fluid sucked into the suction passage from the suction port to divert from a flow of a return fluid returned from the return passage.

A fluid pump with a housing, a fluid duct which is provided in the housing, a temperature sensor which is assigned to the fluid duct in order to detect the temperature of a medium situated therein, and a metal thermally conductive element.

A full-metal anti-high temperature cycloid downhole motor comprises an outer tube, a stator, a rotor, a partition plate, a flow distribution disc, and a flow guide mechanism. The inside of the stator is provided with N grooves, the inner side walls of the N grooves form an annular inner contour surface; the rotor is formed with N−1 rotating heads provided along the axial direction of the outer tube, and each rotating head is provided with an embedding slot, one side of the embedding slot is provided with a notch, a rotor copper rod that can be in rolling engagement with the inner contour surface through the notch is provided in the embedding slot, and there is a changing gap between the outer wall of the rotor copper rod and the inner wall of the embedding slot.

One example of a gerotor pump includes an inner rotor comprising multiple teeth, the inner rotor configured to rotate about a first longitudinal gerotor pump axis. The gerotor pump also includes a hollow outer rotor including an outer surface and an inner surface having substantially identical contours, the inner surface configured to engage with the multiple teeth and to rotate about a second longitudinal gerotor pump axis. The pump includes a pump housing within which the inner rotor and the outer rotor are disposed, wherein the outer surface of the outer rotor defines gaps between the pump housing and the outer rotor.

An oil pump includes: an outer rotor including internal teeth; an inner rotor including external teeth meshing with the internal teeth; a drive shaft connected to the inner rotor and configured to rotationally drive the inner rotor; and a housing including a pump chamber accommodating the inner and outer rotors. In the housing, a suction port and a discharge port are formed. The discharge port includes a first discharge port and a second discharge port. The suction port includes first and second suction ports respectively disposed on the same side as the first and second discharge ports. A pressure reducing oil passage communicating with the second discharge port and configured to reduce pressure of oil in the second discharge port is formed on the side of the second discharge port.

A pump includes an external gear, an internal gear surrounding the external gear to mesh with the external gear, a pump chamber to house the internal gear and the external gear, a suction inlet to suck an oil into the pump chamber, and a discharge outlet to discharge the oil from inside the pump chamber. The housing includes an outer cover having the pump chamber defined therein, and a first oil passage defined in the outer cover and connected to the discharge outlet. The motor shaft includes a second oil passage connected to the first oil passage, and a first through hole to connect the second oil passage to the motor shaft. The second oil passage opens into the first oil passage at the end portion of the motor shaft.