The disclosure provides a pump device capable of suppressing hydraulic amplitude and reducing noise or vibration associated with hydraulic amplitude while simplifying the structure. The pump device includes: a housing which defines a suction port, a discharge port, and an accommodation chamber; and a pump unit which is arranged in the accommodation chamber and which defines a pump chamber that expands and contracts to exert a pumping action including a suction stroke and a pressurization and discharge stroke on a fluid. The housing includes an air introduction hole that is opened to introduce air into the pump chamber at a predetermined opening timing immediately before the suction stroke is completed.

A gear pump includes: an inner rotor having external teeth; an outer rotor having a tubular inner housing portion in which the inner rotor is rotatably housed in an eccentric state, and internal teeth meshing with the external teeth; a first core having a tubular rotor housing portion in which the inner and outer rotors are housed, and a flange portion projecting radially outward from a tube wall of the rotor housing portion; a board-shaped second core having a contact portion in contact with the flange portion in an axial direction, and closing an opening of the rotor housing portion; and a housing opposing the second core and made of a resin. A gap is formed between opposing surfaces of the second core and the housing in a state where the flange portion is in contact with the contact portion and the housing opposes the second core.

A rotary compressor is provided that may include a cylinder having an inner peripheral surface defining a compression space; a roller rotatably provided in the compression space, and including a plurality of vane slots at a predetermined interval along an outer peripheral surface, each providing a back pressure; and a plurality of vanes slidably inserted into the plurality of vane slots to rotate together with the roller, front end surfaces of which come into contact with the inner peripheral surface of the cylinder due to the back pressure to partition the compression space into a plurality of compression chambers. The cylinder may further include a suction flow path for refrigerant that may include a suction port that communicates with the compression space to suction the refrigerant in a lateral direction, and a suction passage disposed in a direction that crosses the suction port to provide communication between the compression space and the suction port.

A vane pump includes a rotor having slits, vanes received in the slits, a cam ring having an inner circumference cam face with which the vanes are brought into sliding contact, a side member, pump chambers formed by the rotor, the cam ring, and adjacent vanes, and back pressure chambers formed in the slits by the vanes. In the vane pump, the side member is provided with a back pressure opening portion opening at a sliding-contact surface in sliding contact with the rotor, the back pressure opening portion being configured to communicate with the back pressure chambers, and a protruding opening portion protruding along the rotating direction of the rotor from an end portion of the back pressure opening portion on the communication-finishing side. An inner-side inner circumferential surface of the protruding opening portion is connected to an inner-side inner circumferential surface of the back pressure opening portion.

A vane pump includes: a suction port configured to guide working oil to a pump chambers; a discharge port configured to guide the working oil discharged from the pump chambers; and a notch formed from an opening edge portion of the suction port towards a reversing direction of a rotation direction of a rotor, wherein the pump chambers each communicates with the suction port through the notch during a course of the transition from the state, in which the pump chamber is in communication with the discharge port, to the state, in which the communication with the discharge port is shut off, as the rotor is rotated.

A vane cell pump, including: a rotor and a plurality of vanes rotatable with the rotor, wherein the rotor includes a sub-vane chamber for each vane, and each vane forms a shifting wall of the sub-vane chamber assigned to it; first and second end-facing walls adjoining the rotor on end-facing sides and which, in order to control pressure to the sub-vane chamber, include sub-vane cavities which extend in the circumferential direction of the rotor and include control edges as viewed in the circumferential direction; wherein the control edge of the sub-vane cavity of the first end-facing wall, and the control edge of the sub-vane cavity of the second end-facing wall which is similar to it, are arranged angularly offset about the rotational axis as the apex with respect to each other.

A low pressure gear pump and wear plate is disclosed. The wear plate may comprise a sidewall, a drive portion, a driven portion, and a transition portion. The sidewall is free of a sealing member or a recess configured to receive the sealing member. The drive portion includes a drive inlet lip, a drive outlet lip, a drive recessed trough and a drive bore. The drive bore is configured to receive the drive shaft of the gear pump. The driven portion may that include a driven inlet lip, a driven outlet lip, a driven recessed trough, and a driven bore. The driven bore is configured to receive the driven shaft of the gear pump. The transition portion may include a transition aperture configured to receive a first fastener configured to mount the wear plate to the gear housing. The wear plate is made of bronze, aluminum or non-magnetic material.

A rotary pump includes a housing featuring a delivery space which the housing surrounds and axially delineates on the end sides; an inner rotor rotatable in the delivery space; an outer rotor rotatable about a pump rotational axis in the delivery space and forming delivery cells with the inner rotor; and a circumferential bearing wall which mounts and surrounds the outer rotor rotatably about the pump rotation axis in radial sliding contact. The circumferential bearing wall includes multiple blind pockets which are radially open towards the outer rotor and/or the outer rotor includes multiple blind pockets which are radially open towards the circumferential bearing wall.

A vane pump includes: a rotor; vanes freely slidably received in the rotor; a cam ring having a cam face with which the vanes come into sliding contact; a side member having a sliding contact surface with which side surfaces of the rotor and the vanes come into sliding contact; pump chambers; and a discharge port configured to guide working fluid discharged from the pump chambers. The side member has a guide surface that is provided on an end portion side of the opening portion, the guide surface being configured to push the end portions of the vanes upward and guide them toward the sliding contact surface of the side member as the rotor is rotated in the reverse rotation direction.

A guided-vane rotary internal combustion engine including a plurality of working chambers which are separated from one another by way of vane assemblies which rotate with a rotor assembly about an axis employs a rotor assembly having a plurality of sectors wherein each sector is associated with a corresponding working chamber and a plurality of spark plugs wherein each spark plug is mounted within a corresponding sector for igniting an air/fuel mixture contained within a corresponding working chamber. A rotor disk is mounted upon the rotor assembly for rotation therewith and acts as a distributor through which energizing charges are conducted to the spark plugs. In addition, a controller is utilized for selectively activating or de-activating the working chambers of the engine upon the occurrence of a predetermined event.