An electric pump actuator for a continuously variable transmission includes a gear wheel pump, a first electric motor, a second electric motor, and an electric control unit. The gear wheel pump has a first gear wheel and a second gear wheel meshing with the first gear wheel. The first electric motor is for actuating the first gear wheel, and the second electric motor is for actuating the second gear wheel independent of the first gear wheel. The electronic control unit is arranged to control the first electric motor to transmit a first torque to the first gear wheel, and control the second electric motor to transmit a second torque to the second gear wheel that is set against the first torque in at least one rotation angle range.

A pressure balancing system for a pump. In one example, the pressure balancing system has: a housing; a first rotor a first shaft, a first face surface; a second rotor, a second face surface adjacent the first face surface of the first rotor; the face of the first rotor, the face of the second rotor, and an inner surface of the housing forming at least one working fluid chamber; an annular ring fitted around a shaft, adjacent a first pressure chamber having a fluid connection through the housing; the annular ring configured to bias the first rotor toward the second rotor when fluid is supplied under pressure to the first pressure chamber; a fluid conduit is configured to convey fluid to a pressure chamber between the housing and the annular ring to bias the annular ring thus biasing the first rotor toward the second rotor.

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.

A vane cell pump, including: a delivery chamber having an inlet and an outlet; a rotor which is arranged in the delivery chamber and has a rotor body and vanes which are accommodated by the rotor body such that they can be shifted radially; an end-facing wall which delineates the delivery chamber on an axial end-facing side; and a supporting element which is arranged axially between the end-facing wall and the rotor body and which supports the vanes at their radially inner vane ends, wherein the rotor body, the supporting element and each two vanes which are adjacent in the circumferential direction of the rotor form chambers, the volume of which varies when the rotor is rotating. A pressure equalization connection fluidically connects at least two of the chambers to each other.

An all-metal conical combined screw pump suitable for petroleum field includes: a stator, a rotor (2), a sleeve (3) and a sucker rod (4), wherein the internal threaded curved surface and the external threaded curved surface are both tapered The spiral structure and the taper are the same, and the end of the inner threaded surface and the outer threaded surface with the larger radial size is adjacent to the sucker rod; the all-metal conical combined screw pump further comprises an elastic telescopic component, wherein the elastic telescopic component comprises a movable part, a fixed part and a elastic part, the movable part is fixedly connected to the rotor, the fixed part is fixedly connected to the sucker rod, the movable part and the fixed part are slidly fitted in the up and down directions and can be To transmit torque to the sucker rod and the rotor, one end of the elastic member abuts against the movable part or the rotor, and the other end abuts against the fixed part or the sucker rod, the elastic member can Elastic contraction or elastic expansion along the sliding direction of the movable part.

A gear pump could be said to include a first gear and a second gear intermeshed with the first gear. An inlet side is configured to have an inlet connection connected thereto. A discharge side is configured to have a first discharge connection connected thereto. At least one shaft is in operable communication with each of the first and second gears. A bearing is configured to support at least one of the shafts via an inner bore and having an outer peripheral surface. A valve bore is formed into bearing between the inner bore and the outer peripheral surface. A second discharge connection is formed into the bearing. A tap provides fluidic communication between the valve bore and a pad defined in the inner bore. A valve is positioned in the valve bore. The valve includes a moving valve member. A spring biases the moving valve member in a direction toward the second discharge connection. A fuel pump system is also disclosed.

An electric pump actuator for a continuously variable transmission includes a gear wheel pump, a first electric motor, a second electric motor, and an electric control unit. The gear wheel pump has a first gear wheel and a second gear wheel meshing with the first gear wheel. The first electric motor is for actuating the first gear wheel, and the second electric motor is for actuating the second gear wheel independent of the first gear wheel. The electronic control unit is arranged to control the first electric motor to transmit a first torque to the first gear wheel, and control the second electric motor to transmit a second torque to the second gear wheel that is set against the first torque in at least one rotation angle range.

A disc valve assembly includes a disc element housed within a housing, the disc element having 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. The valve housing that houses the disc element 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.

Provided is a gear pump or a motor provided with: a casing internally provided with a gear housing compartment in which a pair of gears are housed; a side plate interposed between the casing and the gears; and a gasket which is disposed on a non-slide surface, and which divides a space between the non-slide surface and the casing into a high pressure side and a low pressure side. The gear pump or the motor is configured such that, in order to discover early the mounting of the side plate in a wrong attitude, such as the upper and lower sides thereof being reversed or the high pressure portion side and the low pressure portion side being reversed, flow rate efficiency is decreased when the side plate is in an attitude other than a predetermined attitude, compared to when the side plate is in the predetermined attitude.