Vane pump with undervane feed

A vane pump comprising:

• a) a pump housing hating a cylindrical interior chamber defining a central axis through which a vertical centerline and a horizontal centerline extend;
• b) a cam member disposed within the interior chamber of the pump housing and having a bore extending therethrough and defining a circumferential surface of a pumping cavity, the circumferential surface of the pumping cavity including a discharge arc segment, an inlet arc segment and seal arc segments separating the inlet arc segment and the discharge arc segment from one another;
• c) a cylindrical rotor member mounted for rotational movement within the bore of the cam member about an axis aligned with the central axis of the interior chamber, the rotor member having a central body portion which includes a plurality of circumferentially spaced apart radially extending vane slots formed therein, each vane slot supporting a corresponding vane element mounted for radial movement therein, each vane element having a radially outer tip surface adapted for slideably engaging the circumferential surface of the pumping cavity and a radially inner undervane portion within each vane slot;
• and
• d) means for providing a pressure to the undervane portions of the vane elements when each vane element rotates through the seal arc segments, the pressure comprising a first pressure supplied from a source within the discharge arc segment of the pumping cavity and a second pressure supplied from a source within the inlet arc segment of the pumping cavity, wherein the means includes a plurality of substantially axial fluid passages machined in the central body portion of the rotor, each passage positioned between the plurality of spaced apart radial vanes.

A vane pump comprising

• a) a pump housing having a cylindrical interior chamber defining a central axis through which a vertical centerline and a horizontal centerline extend;
• b) a cam member disposed within the interior chamber of the pump housing and having a bore extending therethrough and defining a circumferential surface of a pumping cavity, the circumferential surface of the pumping cavity including a discharge arc segment, an inlet arc segment and seal arc segments separating the inlet arc segment and the discharge arc segment from one another;
• c) a cylindrical rotor member mounted for rotational movement within the bore of the cam member about an axis aligned with the central axis of the interior chamber, the rotor member having a central body portion which includes a plurality of circumferentially spaced apart radially extending vane slots formed therein, each vane slot supporting a corresponding vane element mounted for radial movement therein, each vane element having a radially outer tip surface adapted for slideably engaging the circumferential surface of the pumping cavity and a radially inner undervane portion within each vane slot;
• d) first and second axially spaced apart end plates disposed within the interior chamber of the pump housing, each end plate having a first surface which is adjacent to the rotor member, each first surface forming an axial end portion of the pumping cavity, each end plate spaced from the rotor member so as to allow frictionless rotation of the rotor member within the pumping cavity;
• and
• e) a first pressure chamber formed in the first surface of the first end plate and a second pressure chamber formed in the first surface of the second end plate, each pressure chamber positioned for fluid communication with the undervane portion of each vane element and providing a desired pressure thereto, each pressure chamber communicating with a first pressure source and a second pressure source through radially inner and radially outer arcuate channels formed in the first surface of each end plate, wherein the first pressure source is associated with the discharge arc segment of the pumping cavity, and the second pressure source is associated with the inlet arc segment of the pumping cavity.