Variable displacement pumps and vane pump control systems

Abstract

A vane pump assembly is provided having a rotor, a plurality of vanes, first and second pistons, at least one fluid passageway, a spring, and an activator. The plurality of vanes adjustably extend from the rotor. The moveable stator ring encircles the rotor and is configured to affect fluid flow when located in offset and non-offset positions relative to the rotor. At least one of the vanes is configured to selectively engage the rotor when the stator ring is located in the offset position to move fluid engaging the vane. The first and second pistons oppose each other and are configured to act on the stator ring to move the stator between offset and non-offset positions relative to the rotor. At least one fluid passageway is in fluid communication with the first piston. The spring is configured to move the second piston. The activator is configured to selectively initiate or cease fluid flow from the vane pump. The spring is configured to move the second piston to move the stator ring to the offset position to create fluid flow by the vanes.

1 . A vane pump comprising:
 a rotor;   a plurality of vanes adjustably extending from the rotor;   a moveable stator ring that encircles the rotor;   wherein the stator ring is configured to affect fluid flow when the stator ring is located in offset and non-offset positions relative to the rotor;   wherein at least one of the vanes is configured to selectively engage the rotor when the stator ring is located in the offset position to move any fluid that engages the vane;   first and second pistons;   wherein the first and second pistons oppose each other and are configured to act on the stator ring to move the stator between offset and non-offset positions relative to the rotor;   at least one fluid passageway in fluid communication with the first piston;   a spring configured to move the second piston;   an activator configured to selectively initiate or cease fluid flow from the vane pump;   wherein the spring is configured to move the second piston to move the stator ring to the offset position to create fluid flow by the vanes;   wherein the vane pump is configured such that selectively ceasing fluid flow by the activator causes fluid from a still moving rotor to divert to the at least one fluid passageway and to first piston so the first piston engages and moves the stator ring against the second piston and spring to move the stator ring to the non-offset position to cease fluid pumping; and   wherein the vane pump is configured such that upon selectively initiating fluid flow by the activator, force from the fluid in the at least one fluid passageway is relieved to allow bias from the spring to move the second piston against the stator ring to move the first piston so the stator ring relocates to the offset position to pump fluid.   
     
     
         2 . The vane pump of  claim 1 , wherein the vane pump is configured such that upon selectively initiating fluid flow by the activator, back pressure from the fluid in the at least one fluid passageway flows. 
     
     
         3 . The vane pump of  claim 1 , wherein the offset position of the stator ring relative to the rotor pumps fluid while the rotor rotates; and wherein the non-offset position of the stator ring relative to the rotor inhibits pumping. 
     
     
         4 . The vane pump of  claim 1 , wherein the activator is a nozzle assembly including an opening to dispense fluid and a trigger to selectively initiate or cease fluid flow from the pump. 
     
     
         5 . The vane pump of  claim 4 , wherein the vane pump is configured to not recycle fluid when the nozzle assembly ceases fluid flow. 
     
     
         6 . The vane pump of  claim 4 , wherein the vane pump is configured such that when the nozzle assembly ceases fluid flow the rotor continues to rotate but there is no longer any substantial pumping load allowing a motor employed to rotate the rotor to be continuous duty instead of having a time-dependent duty cycle. 
     
     
         7 . The vane pump of  claim 1 , further comprising a seal disposed about the periphery of the stator ring. 
     
     
         8 . The vane pump of  claim 7 , wherein a spring biases the seal disposed about the periphery of the stator ring. 
     
     
         9 . The vane pump of  claim 8 , further comprising a port plate located adjacent the stator ring; and wherein the spring biases the seal disposed about the periphery of the stator ring against the port plate. 
     
     
         10 . The vane pump of  claim 9 , wherein the stator ring is movable relative to the port plate. 
     
     
         11 . The vane pump of  claim 1 , wherein the rotor comprises a reservoir in fluid communication with pockets in the rotor; and wherein fluid can enter and exit the pockets via the reservoir based upon movement of the vanes in the pockets. 
     
     
         12 . The vane pump of  claim 11 , wherein each of the pockets further comprises a chamfer between it and the reservoir. 
     
     
         13 . The vane pump of  claim 1 , further comprising a fluid recovery path along an outer periphery of the stator ring. 
     
     
         14 . The vane pump of  claim 13 , wherein the fluid recovery path is in fluid communication with an inlet on the pump that receives fluid, and wherein the fluid recovery path is configured to direct any leaked fluid back toward the inlet. 
     
     
         15 . The vane pump of  claim 1 , further comprising a fluid recovery configured to direct fluid from a shaft seal pocket to an inlet. 
     
     
         16 . The vane pump of  claim 1 , wherein the stator ring is selectively adjustable between offset and non-offset positions to affect to the flow rate of any fluid being pumped.