Abstract: A gear pump comprises a drive gear being mounted for rotation about a first axis and having a plurality of gear teeth at a radially outer location. A driven gear is mounted for rotation about a second axis, and having a plurality of teeth at a radially outer location. The drive gear teeth engage the driven gear teeth at a contact face to cause the driven gear to rotate. Slots are formed in the contact face of one of the drive and driven gear teeth.

Abstract: An example vane pump comprises a shaft driving a rotor. The rotor has a plurality of vane grooves, with a vane received in each of the plurality of vane grooves, and an under vane chamber for communicating a pressurized fluid into the grooves to bias the vanes radially outwardly of the rotor. A cam ring is positioned radially outwardly of the rotor. The cam ring is free to rotate with the rotor through friction from the vanes as the rotor rotates. An inlet delivers a fluid to be pumped into an inlet chamber, and an outlet receives the fluid pumped by the vane pump. An outlet for the fluid biasing the vanes communicates to a main outlet through a passage including a valve to increase the pressure of the fluid in the grooves.

Abstract: An example vane pump comprises a shaft driving a rotor. The rotor has a plurality of vane grooves, with a vane received in each of the plurality of vane grooves, and an under vane chamber for communicating a pressurized fluid into the grooves to bias the vanes radially outwardly of the rotor. A cam ring is positioned radially outwardly of the rotor. The cam ring is free to rotate with the rotor through friction from the vanes as the rotor rotates. An inlet delivers a fluid to be pumped into an inlet chamber, and an outlet receives the fluid pumped by the vane pump. An outlet for the fluid biasing the vanes communicates to a main outlet through a passage including a valve to increase the pressure of the fluid in the grooves.

Abstract: A gear pump comprises a drive gear being mounted for rotation about a first axis and having a plurality of gear teeth at a radially outer location. A driven gear is mounted for rotation about a second axis, and having a plurality of teeth at a radially outer location. The drive gear teeth engage the driven gear teeth at a contact face to cause the driven gear to rotate. Slots are formed in the contact face of one of the drive and driven gear teeth.

Abstract: A dual-inlet gear pump includes a drive gear and a driven gear. The invention utilizes the discovery that the drive gear will typically move a higher flow volume than does the driven gear, particularly when the fluid being moved is an air/oil mixture. The present invention takes advantage of this discovery to communicate a first higher expected flow source to the drive gear, and to separately communicate a second, relatively lower expected flow rate to the driven gear. A particular application is in a scavenging pump for a jet engine.