Variable displacement pump with axial displacement of the vanes

Abstract

The present disclosure relates to a variable displacement vane pump, in particular for oil, comprising a body having a cavity wherein a movable ring slides in the longitudinal direction over the rotor which rotates around an axis and which is provided with vanes which are radially supported on the inner surface of the fixed ring of fixed eccentricity relative to the rotation axis of the rotor, and with movement means in the longitudinal direction of the movable ring according to a pilot pressure between a position corresponding to the maximum volume of the plurality of chambers, the return elastic spring being in this position at its maximum length, and a predetermined end position corresponding to the minimum volume of the plurality of chambers, the return elastic spring being in this position at its minimum length by action of the displacement in the longitudinal direction of the movable wall which occurs simultaneously to the longitudinal displacement of the plurality of vanes and of the movable ring.

1 . A variable displacement vane pump of the type having a body with a fixed ring fixed to said body, a rotor provided with a plurality of radial vanes, wherein each vane is adapted to slide radially in a corresponding slot in said rotor, wherein the vanes slide along the circular inner surface of said fixed ring, and wherein the rotation axis of the rotor is eccentric relative to the axis defined by the circular inner surface of the fixed ring, the displacement vane pump comprising:
 a movable ring adapted for sliding longitudinally along the rotor; and
 a fixed body that is not longitudinally slidable over the rotor, 
 wherein each of the vanes is adapted for sliding longitudinally along the rotor in the corresponding slot in said rotor, passing through and sealing in openings of the side surface of the fixed body in one of the longitudinal tops of the vane, and sealing with a side surface of the movable ring in the other of the longitudinal tops of the vane, 
   defining chambers between vanes of variable longitudinal length arranged among the side surface of the movable ring, side surface of the fixed body, outer surface of the rotor and circular inner surface of the fixed ring.   
     
     
         2 . The variable displacement vane pump according to  claim 1 , wherein the fixed body is fixed to the rotor and rotates jointly with the rotor. 
     
     
         3 . The variable displacement vane pump according to  claim 1 , wherein the fixed body and the rotor are formed by the same part. 
     
     
         4 . The variable displacement vane pump according to  claim 1 , wherein the movable ring has the cross-section of a surface delimited by two non-concentric circumferences wherein one of the circumferences is completely contained by the other circumference. 
     
     
         5 . The variable displacement vane pump according to  claim 1 , further comprising force means for longitudinally moving the movable ring and the vanes. 
     
     
         6 . The variable displacement vane pump according to  claim 1 , wherein the force means comprise a return elastic spring for longitudinally moving the movable ring and the vanes up to their initial position. 
     
     
         7 . The variable displacement vane pump according to  claim 5 , further comprising force means for applying longitudinal force on the movable ring for longitudinally moving the movable ring and the vanes in order to increasing the volume of said chambers. 
     
     
         8 . The variable displacement vane pump according to  claim 5 , wherein the force means comprise a pilot chamber delimited by the side surface of the movable ring opposite to the side surface of the movable ring which seals with longitudinal tops of the vanes, wherein the pilot chamber comprises a channel for receiving pressure from an external pressure source. 
     
     
         9 . The variable displacement vane pump according to  claim 1 , wherein the pilot chamber is connected to the pump outlet. 
     
     
         10 . The variable displacement vane pump according to  claim 1 , wherein the force means are mechanically or electronically controlled. 
     
     
         11 . The variable displacement vane pump according to  claim 1 , further comprising a wall which leans laterally against to the longitudinal top of the vanes passing through the fixed body, for applying longitudinal force to said vanes. 
     
     
         12 . The variable displacement vane pump according to  claim 11 , further comprising force means for applying longitudinal force on said wall for longitudinally moving the movable ring and the vanes in order to decrease the volume of said chambers. 
     
     
         13 . The variable displacement vane pump according to  claim 1 , wherein the fixed ring is of a more wear resistant material than the material of the pump body. 
     
     
         14 . The variable displacement vane pump according to  claim 1 , wherein the pump is configured for pumping oil. 
     
     
         15 . A vehicle including a variable displacement vane pump according to  claim 1 . 
     
     
         16 . The vehicle of  claim 15 , wherein the variable displacement vane pump is a component of an engine of the vehicle.