Vane pump

Abstract

A vane pump having a pump containing a rotor driven via a drive shaft with the rotor having a number of generally radially extending grooves distributed over its circumference each of which grooves support a vane shaped delivery element in sliding fashion. The rotor is encompassed by an eccentric circumferential wall, against which the radially outer ends of the vanes rest. Housing end walls are situated adjacent to the rotor in the direction of its rotation axis. When the rotor turns, the vanes deliver medium from a suction region to a pressure region offset in the rotation direction. An annular groove is provided in at least one of the housing end walls which annular groove encompasses the rotation axis of the rotor, is situated opposite the inner regions delimited in the grooves of the rotor by the vanes, and is connected to the pressure region via a connecting groove in the housing end wall. The annular groove extends in eccentric fashion in relation to the rotation axis of the rotor.

1 - 5 . (canceled) 
   
   
       6 . In a vane pump having a pump housing that contains a rotor driven to rotate via a drive shaft and which has a number of grooves distributed over its circumference that extend at least essentially in a radial direction in relation to the rotation axis of the rotor, each of which grooves has a respective vane-shaped delivery element guided in it in sliding fashion; having a circumferential wall of the pump housing encompassing the rotor and extending eccentrically in relation to its rotation axis, against which circumferential wall the radially outer ends of the delivery elements rest; having housing end walls of the pump housing that are situated adjacent to the rotor in the direction of its rotation axis, in which, when the rotor turns, the delivery elements deliver medium from a suction region to a pressure region offset from the suction region in the rotation direction of the rotor and an annular groove in at least one of the housing end walls in the suction region which annular groove extends over at least part of the circumference of the rotor and is situated opposite the inner regions delimited in the grooves of the rotor by the delivery elements, and a sealing region formed between the annular groove and the drive shaft, the improvement wherein the annular groove extends over the entire circumference of the rotor, is connected to the pressure region via a connecting groove in the housing end wall, and is embodied as eccentric in relation to the rotation axis of the rotor. 
   
   
       7 . The vane pump according to  claim 6 , wherein the annular groove extends in an at least approximately circular fashion and its center point (M) is offset in relation to the rotation axis of the rotor toward a region of the circumferential wall of the pump housing situated between the suction region and the pressure region in the rotation direction of the rotor. 
   
   
       8 . The vane pump according to  claim 6 , wherein in a circumferential region situated between the suction region and the pressure region in the rotation direction of the rotor, the annular groove is spaced a greater radial distance apart from the rotation axis of the rotor than in the opposite circumference region. 
   
   
       9 . The vane pump according to  claim 6 , wherein the annular groove extends in such a way that it at least approximately follows the stroke of the vanes in the grooves of the rotor as the latter turns. 
   
   
       10 . The vane pump according to  claim 6 , wherein the eccentricity of the annular groove is at least approximately of the same magnitude and oriented in the same direction as the eccentricity of the circumferential wall of the pump housing. 
   
   
       11 . The vane pump according to  claim 7 , wherein the eccentricity of the annular groove is at least approximately of the same magnitude and oriented in the same direction as the eccentricity of the circumferential wall of the pump housing. 
   
   
       12 . The vane pump according to  claim 8 , wherein the eccentricity of the annular groove is at least approximately of the same magnitude and oriented in the same direction as the eccentricity of the circumferential wall of the pump housing. 
   
   
       13 . The vane pump according to  claim 9 , wherein the eccentricity of the annular groove is at least approximately of the same magnitude and oriented in the same direction as the eccentricity of the circumferential wall of the pump housing.