A gear pump or a gear motor includes a casing, a helical drive gear, a helical driven gear, a drive-side space, and an idler-side space. The drive and driven gears mesh with each other in the casing to partition inside of the casing so as to include high and low pressure spaces. The drive-side and idler-side spaces are each configured to allow pressure therein to become higher than a pressure in the low-pressure space. The drive-side space faces an end portion of a drive shaft rotatably supporting the drive gear. The idler-side space faces an end portion of an idler shaft rotatably supporting the driven gear. The end portion of the drive shaft is pushed in a predetermined direction by working fluid supplied to the drive-side space. The end portion of the idler shaft is pushed in the predetermined direction by working fluid supplied to the idler-side space.

A screw compressor includes a screw rotor including a rotor shaft, a radial bearing, a thrust plate, a balance mechanism, which is a slide bearing, a lubrication oil supply flow passage for supplying a lubrication oil, and a working fluid supply flow passage for supplying a working fluid for pressing the balance mechanism toward the thrust plate so that a reverse thrust load acts on the thrust plate.

A rotary positive displacement pump for fluids, in particular for the lubrication oil of a motor vehicle engine (60), has a displacement that can be regulated by means of the rotation of a stator ring (12) having an eccentric cavity (13) in which the rotor (15) of the pump (1) rotates. The stator ring (12) is configured as a multistage rotary piston for displacement regulation and is arranged to be directly driven by a fluid under pressure, in particular oil taken from a delivery side (19) of the pump or from a point of the lubrication circuit located downstream the oil filter (62). The invention also concerns a method of regulating the displacement of the pump (1) and a lubrication system for a motor vehicle engine in which the pump (1) is used.

An electrical submersible pump assembly has a thrust bearing mechanism with first and second thrust runners axially and rotationally secured to the shaft and located within a housing. First and second thrust receiving structures are rigidly mounted in the housing to receive thrust from the first and second thrust transferring devices. A deflectable member located in the first thrust transfer thrust device decreases in axial thickness in response to thrust of a selected level. The second thrust transfer thrust device has an axial length less than an axial distance from the second thrust receiving structure to the second thrust runner, defining an initial axial gap. During operation of the pump, the shaft and the first and second thrust runners move axially a limited extent, closing the gap and transferring thrust from the second thrust transfer device to the second thrust receiving structure.

A containment assembly for a pump provided with at least one pumping group and with at least one power transmission system to such a pumping group. The containment assembly comprises a substantially cylindrical containment vessel provided with an opening at one of the ends thereof, configured to at least partially enclose the pumping group and the respective power transmission system. The containment assembly also comprises at least one closure plate, sealably coupled with the containment vessel at the open end thereof and configured to hermetically enclose, in cooperation with such a containment vessel, the pumping group and the respective power transmission system. On a predetermined contact portion between the containment vessel and the closure plate at least one wave spring is provided, configured to keep the pumping group dynamically under compression by means of the closure plate.

Methods and apparatus pertaining to positive displacement pumps, and further to hydraulic actuation systems. In some embodiments the pumps are gear pumps with bi-directional operation. In some embodiments the actuation system includes a motor-driven, reversible operation gear pump providing fluid under pressure to a rod and cylinder.

Rotary positive displacement machines based on trochoidal geometry and including a helical rotor that undergoes planetary motion relative to a helical stator can be designed and configured so that the axial load or rotor pressure force is positive, negative, or neutral. In some embodiments, a change in axial load, caused by a change in differential pressure across the machine, can be used to trigger a change in a mechanical configuration of the machine.

One embodiment of a pump may include an idler gear having a plurality of idler gear teeth extending radially outward, wherein at least one of the idler gear teeth may be formed with an idler gear cavity therein. The pump may include a drive gear having a plurality of drive gear teeth extending radially outward that may be intermeshed with the idler gear teeth during use. The drive gear may be formed with a recess at on axial end thereof, and the axial position of the recess may correspond to the axial position of the idler gear cavity. In one embodiment of a pump, each idler gear tooth may be formed with an identical idler gear cavity at the same relative position on each idler gear tooth.

A fluid pump includes a stator. A rotor is rotationally operable with respect to the stator. A drive shaft extends from the rotor to a pump assembly that delivers a fluid from an inlet to an outlet. A pump housing includes an interior cavity that contains the stator, the rotor and the pump assembly. A pump cover is disposed at an end of the pump housing. The pump cover defines an end of the interior cavity. A spring assembly biases the pump cover in an axial direction toward the pump assembly.

An internal gear pump or motor includes inner and outer rotors that mesh together. An internal electric motor or generator may include a stator supported by a support element that passes through bearings of the outer rotor and the inner rotor may act as a rotor of the electric motor or generator. With or without the stator, the support element may support bearings of the inner rotor. The support element may be, for example, an eccentric shaft. Fluids may be supplied via the support element, if present, for cooling, lubrication or to flush a working fluid out of portions of the pump or motor, such as bearings. Flushing may also occur via channels in the housing with or without the presence of the support element. Axial faces of one of a pair of adjacent elements, for example the inner rotor and the outer rotor, may include portions for improved axial sealing and wearing in of the other of the pair. Fluid may enter and exit chambers between the inner and outer rotors by radial ports