A variable displacement gear pump comprises a fixed gear, a movable gear movable, a fixed gear ring fitted over the movable gear, a movable gear ring fitted over the fixed gear, a fixed cover having a hole in which the fixed gear ring rotates, a movable cover having a hole in which the movable gear ring rotates, a fixed gear block attached to the fixed cover, and a movable gear block attached to the movable cover. The fixed gear is engaged with the movable gear. The movable gear ring rotates in the hole of the movable cover, and the fixed gear ring rotates in the hole of the fixed cover. The movable gear, together with the movable cover, the movable gear, and the movable gear block, move along the direction of the shaft to change a width in which the fixed gear is engaged with the movable gear.

The invention relates to a continuously variable transmission and a transmission system comprising said continuously variable transmission, wherein the continuously variable transmission comprises a first gear pump and a second gear pump, wherein each gear pump comprises a first gear and a second gear meshing with the first gear over an overlap distance in an overlap direction parallel to the first gear axis, wherein each gear pump further comprises an adjustment member for adjusting the pump volume, wherein the adjustment member of the first gear pump and the adjustment member of the second gear pump are interconnected by a connecting member for adjusting the pump volume of the first gear pump and the pump volume of the second gear pump in an inverse correlation to each other.

A pump including a port connecting a suction of the pump to a reservoir of a fluid; region an adjusting device for adjusting the delivery volume of the pump; a control valve, including a relief port, a control piston, and a tensing device which acts on the control piston; and an additional control device for generating a control force which acts on the control piston, counter to the tensing device, wherein the relief port is connected to the suction region by bypassing the reservoir.

A progressing cavity pump has: a stator; a rotor; the rotor having a first axial operating position within the stator in which a first axial part of the rotor aligns with a first axial part of the stator to form an active pump section adapted to generate a pumping force on rotation of the rotor in the stator; the rotor having a second axial operating position within the stator in which the first axial part of the rotor aligns with a second axial part of the stator to form an active pump section adapted to generate a pumping force on rotation of the rotor in the stator. A related method is disclosed.

The present disclosure relates to a variable displacement vane pump, in particular for oil, comprising a body having a cavity wherein a movable ring slides in the longitudinal direction over the rotor which rotates around an axis and which is provided with vanes which are radially supported on the inner surface of the fixed ring of fixed eccentricity relative to the rotation axis of the rotor, and with movement means in the longitudinal direction of the movable ring according to a pilot pressure between a position corresponding to the maximum volume of the plurality of chambers, the return elastic spring being in this position at its maximum length, and a predetermined end position corresponding to the minimum volume of the plurality of chambers, the return elastic spring being in this position at its minimum length by action of the displacement in the longitudinal direction of the movable wall which occurs simultaneously to the longitudinal displacement of the plurality of vanes and of the movable ring.

A fluid transfer device comprising an inner member with a central axis and an outer surface; an outer member coaxially arranged with the inner member, and a space defined radially between the inner and outer members; a first and second axial members; at least one fluid chamber defined in the space having an inlet and an outlet; the first axial member is rotationally fixed relative to the outer member and the second axial member is rotatable about the central axis to vary the volume of the fluid chamber. The relative rotational position of the first and second axial members is defined by a cam arrangement which comprises first and second axial member walls; the first axial member wall forms a first cam track wall which provides a first cam track waveform, the second axial member wall which comprises a second cam track wall; each cam track wall is circumferentially continuous.

A variable displacement gear pump comprises a fixed gear, a movable gear movable, a fixed gear ring fitted over the movable gear, a movable gear ring fitted over the fixed gear, a fixed cover having a hole in which the fixed gear ring rotates, a movable cover having a hole in which the movable gear ring rotates, a fixed gear block attached to the fixed cover, and a movable gear block attached to the movable cover. The fixed gear is engaged with the movable gear. The movable gear ring rotates in the hole of the movable cover, and the fixed gear ring rotates in the hole of the fixed cover. The movable gear, together with the movable cover, the movable gear, and the movable gear block, move along the direction of the shaft to change a width in which the fixed gear is engaged with the movable gear.

A pump, including: inlet port and outlet ports; a cylinder block including a piston disposed in a through-bore; a swash plate engaged with the piston; a drive shaft non-rotatably connected to the drive shaft, arranged to rotate the cylinder block to draw fluid through the inlet port into the through-bore and to expel the fluid from the through-bore and through the outlet port and including an axis of rotation; an axis transverse to the axis of rotation; and an actuator including a roller screw; a nut disposed about the roller screw and in threaded contact with the roller screw; an actuator pin; and an electric motor arranged to rotate the roller screw or the nut to axially displace the actuator pin to pivot the swash plate or the cylinder block about the axis and control an amount of the fluid expelled from the through-bore.

This document discloses an internal gear pump with a symmetrical casing and a head design that enables high pumping speeds, reduced turbulence and reduced risk or occurrence of cavitation. The head includes a boss that extends into the pump chamber to form an idler support and a crescent support. The crescent support includes a liquid directing step that extends from the crescent arcuately towards the inlet. The liquid directing step divides liquid incoming from the inlet into a portion directed to an idler feed slot and another portion directed to a rotor feed slot. The idler feed slot provides communication between the inlet and the roots of the idler and the rotor feed slot provides communication between the inlet and spaces between the rotor teeth.

The movement of the moving gear meshed with the fixed gear in the casing changes the meshing width of the two gears, thereby changing the discharge amount of the pump. By installing a gear block inside the fixed gear, which is an internal gear, and a gear ring and gear ring cover on the outside of the moving gear, the fluid between the two gears is prevented from leaking to the outside. The fluid can pass between the two gears from or to the outside through the fluid holes in the fixed gear and the fluid inlets in the pumping chamber in the casing. The part of the fixed gear that is not engaged with the moving gear can be used as a hydraulic chamber.