An internal gear pump includes a pinion, a ring arranged around the pinion, and a cylindrical wall arranged around the ring. A support element, on which the pinion and the ring are supported, carries high-pressure liquid towards a recess located at the junction between the ring and the cylindrical wall, and also carries low-pressure liquid towards another recess located at another point of the junction between the ring and the cylindrical wall. The recess allows the load of the ring on the cylindrical wall to be reduced.

An improved screw-spindle pump, particularly for cooling systems, includes a first screw, a second screw and a pump housing, inside which the first screw and the second screw are rotatably housed between the first screw, the second screw and the pump housing, being defined pumping chambers adapted to move, as a consequence of the rotation of the first screw and the second screw, a fluid from a suction area to a delivery area of the pump.

The pump housing housing the first screw and the second screw is made in one piece.

A rotary pump includes: a pump rotor having a flat rotor side surface facing in an axial direction; a housing body having an opening in the axial direction and a flat flange surface formed around the opening, the housing body rotatably housing the pump rotor in the opening such that the rotor side surface is flush with the flange surface; and a cover member having a flat mating surface that is fixed while being pressed against the flange surface by fastening of a bolt, and a flat sliding/guiding surface that slides and guides the rotor side surface. The cover member is formed of a crosslinked fluororesin and a metal body. The metal body is provided with the mating surface, and a recess obtained by recessing an area corresponding to the sliding/guiding surface, in the axial direction with respect to the mating surface.

Provided is a rotary pump including: a pump rotor having a flat first rotor side surface facing one side in an axial direction, and a flat second rotor side surface facing the other side in the axial direction; and a housing configured to rotatably house the pump rotor. The housing includes: a ring member having a hollow tubular shape and openings at both ends in the axial direction; a first side member detachably mounted to one end in the axial direction of the ring member to slide and guide the first rotor side surface by using a first crosslinked fluororesin flat surface formed of a crosslinked fluororesin; and a second side member detachably mounted to the other end in the axial direction of the ring member to slide and guide the second rotor side surface by using a second crosslinked fluororesin flat surface formed of the crosslinked fluororesin.

The invention relates to a dual-spindle helical spindle pump with a single-entry design, comprising a pump housing (11) which has a pump portion (12), a bearing portion (13) and a gear portion (14) with a gear chamber, wherein the bearing portion (13) and the pump portion (12) are designed separately from one another, comprising a feed housing part (50) as a component of the pump portion (12) in which two feed screws (17, 18) are provided, said feed screws having flanks (46) and being arranged on shafts (15, 16) in a feed space (51), wherein the shafts (15, 16) are mounted in the bearing portion (13) (external bearing system) and extend into the gear portion (14), and wherein the feed housing part (50) has at least one feed portion (52) with an inner wall (58) which faces the outer face (59) of the feed screws (17, 18). The invention provides that at least one separating element (60), which is in contact with at least one portion of the outer face (59) of the feed screws (17, 18), is between the inner wall (58) of the feed portion (52) and the outer face (59) of the feed screws (17, 18), at least in the region (57) of the feed screws (17, 18), and in that the separating element (60) is floatingly mounted in the feed housing part (50) relative to the inner wall (58) of the feed portion (52).

An oil pump includes: a shaft member; an inner rotor configured to rotate integrally with the shaft member; an outer rotor forming a rotor chamber into which oil is sucked from a suction passage and from which the oil is discharged toward a discharge passage, between the inner rotor and the outer rotor; a body member having a recess-shaped housing chamber in which each rotor is housed so as to be rotatable about an axis; and a cover member attached so as to close the housing chamber. The rotor chamber has first and second suction ports through each of which the oil to be sucked from the suction passage passes. The oil pump includes a straightening member branching the suction passage from a main path to the first suction port side and the second suction port side.

A pump includes a casing defining an interior volume. The pump casing includes at least one balancing plate that can be part of a wall of the pump casing with each balancing plate including a protruding portion having two recesses. Each recess is configured to accept one end of a fluid driver. The balancing plate aligns the fluid displacement members with respect to each other such that the fluid displacement members can pump the fluid when rotated. The balancing plates can include cooling grooves connecting the respective recesses. The cooling grooves ensure that some of the liquid being transferred in the internal volume is directed to bearings disposed in the recesses as the fluid drivers rotate.

A pump device includes a rotating body, a pump housing including a suction port and a discharge port, and a relief valve. In the pump device, a fluid is sucked from the suction port and discharged from the discharge port by rotation of the rotating body. The relief valve includes a valve body and a biasing member. The discharge port includes an one end in a direction in which the discharge port extends. The one end is shallower than a middle portion of the discharge port. The pump housing includes a relief flow path through which the fluid flows when the relief valve opens. The relief flow path is provided so as to be open to a groove bottom surface of the one end of the discharge port.

A gear pump or a gear motor in which a tooth groove is easily filled with a liquid. A gear pump includes a casing, a gear storage chamber, a suction passage, a discharge passage, a gear that is housed in the gear storage chamber and including a drive gear and a driven gear that rotate while meshing with each other, and a suction-side communication path that connects a first space and a tooth groove of the gear, the first space being a closed space formed by the drive gear and the driven gear meshing with each other, the tooth groove being opened to the suction passage.

A groove is applied to one or more contact surfaces of a journal bearing of a pump to increase a force applied to the contact surface(s). Each groove has an end exposed to discharge pressure of the pump so that the groove communicates the discharge pressure across the contact surface. The groove reduces an area of the contact surface over which fluid leakage results in a pressure differential, thereby increasing a net force applied to the contact surface. Applying the groove to the axial end face of the journal bearing enhances an axial force applied to the journal bearing whereas applying the groove to a radially facing land reduces friction between the journal bearing and the outer housing.