The present invention relates to a fixed displacement pump for use for conveying a hydraulic fluid in a closed hydraulic circuit, a closed hydraulic circuit, a construction machine and a method for operating a fixed displacement pump in a closed hydraulic circuit.

An example hydraulic motor comprises: a stator comprising (i) a stator body having plurality of roller pockets, wherein the stator body comprises a plurality of grooves that are longitudinally-extending, and (ii) a plurality of rollers disposed respectively in the plurality of roller pockets; a rotor having a plurality of external teeth configured to engage with the plurality of rollers of the stator, such that the plurality of rollers and the plurality of external teeth define fluid chambers therebetween configured to expand and contract as the rotor rotates within the stator; and an anti-cogging passage configured to provide pressurized fluid from at least one of the fluid chambers to at least one groove of the plurality of grooves of the stator body, such that pressurized fluid provided to the at least one groove applies a radially-inward force on a respective roller toward the rotor.

A highly reliable horizontal rotary compressor is provided with a sealed housing, an electric motor, a compression mechanism, a frame which divides the inside of the sealed housing into an electric-motor chamber and a compression-mechanism chamber, and a plurality of bolts that fasten the compression mechanism to the frame. The compression mechanism includes a main bearing fasten to the end surface of a cylinder. A bearing contact-surface of the end surface of the cylinder is in contact with the main bearing, is located closer to the electric motor than a frame contact-surface which is in contact with the frame. The surface roughness of the frame contact-surface is greater than the surface roughness of the bearing contact-surface. The contact-surface of the frame is a single continuous flat surface located above the bolt located at the lowest position among the plurality of bolts.

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.

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.

Several examples of a pressure balancing system for a pump. In one example, the pressure balancing system comprises: a housing; a first rotor within the housing having a first axis of rotation, a first shaft, a first face surface; a second rotor having an axis of rotation, 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 against a radial extension of the first shaft thus biasing the first rotor toward the second rotor.

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.

A gerotor pump having an inner rotor and an outer rotor, which is also the rotor of an electric drive, having a housing and a flange which closes the housing with the motor compartment, the rotor being arranged on a shaft and sealing against the flange at a gap, wherein, in addition to the gap, there is at least one device with which at least a partial pressure compensation takes place between the suction region of the gerotor pump and the motor compartment of the gerotor pump.

An oil pump, in particular an electric or electromotive auxiliary pump for a motor vehicle, having a housing having an inlet on the admission side and an outlet on the pressure side, in addition to a pump rotor which is inserted in the housing such that it can rotate about an axis, and having at least one rotor part, a flexible housing component which is in the form of an elastic press plate and which extends over the cross-sectional surface of the pump rotor. The flexible pressure plate is maintained, in an advantageous manner, in the edge area of the second housing parts.

The application relates to an internal gear machine for reversing duty having a housing with a chamber, in the chamber there are disposed an externally toothed pinion and an internally toothed ring gear, which mesh with one another, the rotational axes of which run parallel to and spaced apart from one another. The chamber in the housing is axially bounded and is connected via pressure pockets provided in the housing to pressure connections in the internal gear machine. According to the invention, a switching valve is arranged in each connection between the pressure pockets and the pressure connections or compression spaces, which valve opens or closes the connection.