A uniaxial eccentric screw pump includes: a stator 8 having a through hole 8a whose inner surface is formed in a female screw shape; a rotor 14 that is a male screw shaft body inserted into the through hole 8a of the stator 8; a plurality of shims 9 that are arranged on a radially outside of the stator 8 in a range from one end to the other end of the stator 8, are in surface contact with an outer surface of the stator 8, are capable of compressing the stator 8 by moving radially inward with respect to the stator 8, and have, on an outer surface, an inclined surface 18 gradually inclined radially inward or outward toward one end; and an adjustment member 10 that is movable in an axial direction with respect to the stator 8 and has a pressing part 26 that can press the inclined surface 18 of each of the shims 9.

A pump includes a front plate, a gear plate and a rear plate. A drive shaft has a drive gear, an arbor has a driven gear engaged with the drive gear, and first and second bearings are disposed in the gear plate. The first and second bearings receive the drive shaft and the arbor. The rear plate has drain ports adjacent ends of the drive shaft and the arbor. The arbor has an opening such that media that passes between the first bearing and an outer surface of the arbor is directed to the second drain port via the opening. A drain bushing is positioned against the front plate, and includes an opening for the drive shaft. The drain bushing has a chamber and a radial port. When pumped media passes between the first bearing and the drive shaft it is directed to the chamber and out the radial port.

An improved screw pump such as, for example, a twin screw pump is disclosed. In one embodiment, the screw pump includes a casing, first and second intermeshing rotors, and a liner positioned between the first and second rotors and the casing. In use, the liner is arranged and configured to bend and/or pivot in unison with the first and second rotors under the axial hydraulic pressure experienced by the screw pump during use. In one embodiment, the liner may be arranged and configured to include an asymmetric axial stiffness to facilitate bending of the liner. In another embodiment, the liner may be arranged and configured in multiple segments, the segments being arranged and configured to pivot to approximate the bending of the rotor shafts.

A disc valve assembly for control of a flow of hydraulic fluid in a hydraulic fluid system may include a disc element comprising an inlet facing side and a second side opposite to the inlet facing side, and flow pathways configured as a plurality of different pressure zones with the flow pathways extending axially along a longitudinal axis of the disc element from at or adjacent to the inlet facing side to the second side. A valve housing houses the disc element and includes porting configured as part of the plurality of different pressure zones respectively in fluid communication with the flow pathways of the disc element. The disc element is configured to rotate to control a flow of hydraulic fluid through the disc valve assembly. The different pressure zones are isolated from each other using a plurality of annular sealing rings located on the inlet facing side of the disc element.

A screw pump with a housing; a housing cover; at least one idler screw held in a bore in the housing; and a bushing arranged on the housing cover with a receiving space bounded by a cylindrical flange, into which one end of the idler screw engages; wherein the bushing has an opening in its base, through which a fluid, supplied by a feed channel in the cover, can be supplied from the end opposite the idler screw under pressure to the end surface of the idler screw, wherein the bushing engages with radial play in a receptacle in the cover and comprises a radial flange, by which it is supported axially on the housing; and wherein at a least certain part of the ring-shaped flange of the bushing engages in the bore and is accommodated therein with play.

A motor pump unit with a multipart housing comprises a reversible internal gear machine and an electric motor with a rotor and a stator, which is coupled to the internal gear machine via a shaft rotatably mounted in the housing. One shaft end extends from the internal gear machine axially through the rotor that is carried by the shaft. First and second connecting channel ends in the working chamber of the internal gear machine are connected via check valves in the housing to a leakage channel loop, which is fluidically connected to a leakage channel that is fluidically connected to the working chamber, and which has a shaft leakage channel extending axially through the shaft and a rotor leakage channel that is fluidically connected thereto and extends axially through the rotor and/or a gap leakage channel between the rotor and stator, which is fluidically connected to the shaft leakage channel.

A pump apparatus includes a shaft, a first pump, and a second pump. The first pump includes a first driving gear disposed on the shaft in a first phase and rotatable with the shaft to feed a first operating fluid. The second pump includes a second driving gear disposed on the shaft in a second phase shifted from the first phase. The second driving gear is coaxial with the first driving gear and rotatable with the shaft to feed a second operating fluid.

A hydraulic machine (1) such as a pump or motor includes a working section (6) such as a gerotor. A spool (3) is rotatable about an axis (4) within a bore of the machine housing (2). The spool includes hydraulic fluid directing passages that enable operation of the machine. The spool includes first and second axially spaced apart circumferential grooves (14, 15). A plurality of first axial grooves (16) extend in intersecting relation with the first circumferential groove and a plurality of second axial grooves (17) extend in intersecting relation with the second circumferential groove. The first and second axial grooves are arranged in alternating relation about the circumference of the spool. The circumferential grooves are bounded radially inwardly by respective bottom walls (19, 22) that have a greater radial distance from the axis with axial proximity to the intersecting grooves.

An eccentric screw pump with a rotor (2) and with a rotationally fixed stator (6; 6) surrounding the rotor (2). The rotationally fixed stator includes at least one elastomeric portion, wherein a pressure chamber (16) is arranged on this elastomeric portion of the stator (6; 6) at a side facing away from the rotor (2). The pressure chamber (16) is connected to a pressure region of the eccentric screw pump such that the at least one elastomeric portion of the stator (6; 6) is subjected to a pressure produced by the eccentric screw pump.

A pump device includes a shaft, a first gear pair, a second gear pair, a support pin, and a casing. The first gear pair includes a first driving gear which is disposed on the shaft and is rotatable together with the shaft, and a first driven gear driven by the first driving gear. The second gear pair includes a second driving gear which is disposed on the shaft coaxially with the first driving gear and is rotatable together with the shaft, and a second driven gear driven by the second driving gear and arranged coaxially with the first driven gear. The support pin penetrates the first driven gear and the second driven gear and rotatably supporting the first driven gear and the second driven gear. The casing covers the first gear pair and the second gear pair. The support pin is fitted to the casing to be fixed.