Vane pumps

Abstract

A rotor for a pump includes a rotor body, an undervane cavity defined in the rotor body configured to accept an underside of a vane, an outer surface on a periphery of the rotor body for defining overvane cavities within a liner as a function of an inner cammed surface of the liner, and a pressure balance aperture defined in the rotor body fluidly connecting the undervane cavity to at least one of the outer surface.

What is claimed is: 
     
         1 . A pump, comprising:
 a liner, wherein the liner includes an inner cammed surface;   a rotor disposed within the liner and configured to rotate therein, the rotor including an undervane cavity and an outer surface for defining overvane cavities within the liner as a function of the inner cammed surface, wherein the rotor includes a pressure balance aperture defined therein fluidly connecting the undervane cavity to the outer surface; and   a plurality of vanes disposed in the rotor and in contact with the cammed surface within the liner, a follower portion of the vanes extending from the rotor radially outwardly and an underside of the vanes extending at least partially into the undervane cavity, wherein the vanes circumferentially define cavities of differing sizes therebetween within the liner in conjunction with the inner cammed surface of the liner and the outer surface of the rotor.   
     
     
         2 . The pump of  claim 1 , further including a plurality of pressure balance apertures defined in the rotor in communication with the undervane cavity. 
     
     
         3 . The pump of  claim 1 , further including a plurality of vanes and undervane cavities. 
     
     
         4 . The pump of  claim 3 , further including a plurality of pressure balance apertures defined in the rotor for each undervane cavity. 
     
     
         5 . The pump of  claim 1 , wherein the outer surface includes an axially asymmetric shape. 
     
     
         6 . The pump of  claim 1 , wherein the outer surface includes a smooth shape. 
     
     
         7 . A rotor for a pump, comprising:
 a rotor body;   an undervane cavity defined in the rotor body configured to accept an underside of a vane;   an outer surface on a periphery of the rotor body for defining overvane cavities within a liner as a function of an inner cammed surface of the liner; and   a pressure balance aperture defined in the rotor body fluidly connecting the undervane cavity to at least one of the outer surface.   
     
     
         8 . The rotor of  claim 7 , further including a plurality of pressure balance apertures defined in the rotor in communication with the undervane cavity. 
     
     
         9 . The rotor of  claim 7 , further including a plurality of undervane cavities. 
     
     
         10 . The rotor of  claim 9 , further including a plurality of pressure balance apertures defined in the rotor for each undervane cavity. 
     
     
         11 . The rotor of  claim 7 , wherein the outer surface includes an axially asymmetric shape. 
     
     
         12 . The pump of  claim 7 , wherein the outer surface includes a smooth shape.