Control mechanism for cam phaser

Abstract

A VCT phaser having a mechanical feedback in which no elaborate sensors and its concomitant electronic control loop is required. The phaser has centerly mounted spool valve controlling the flow of control fluid such that when a command positions the same at a predetermined position, passages within the phaser adjusts to a desired position through the mechanical feedback.

1 . A phaser, comprising: 
 a housing having at least one cavity therein;    a rotor having at least one vane oscillating within the at least one cavity of the housing, the rotor being disposed to engage the housing, or rotate relative to the housing, the cavity being divided into an advance chamber and a retard chamber by the at least one vane; and    a control valve disposed to translationally move within an opening of the rotor along a substantially straight line, the control valve having at least two openings for selectively controlling fluid flow among a set of passages within the phaser for control fluid to occupy either the advance chamber or the retard chamber;    at the outer surface of the control valve, a helical slot having at least one side, wherein a non-zero angle exists between the at least one side and the substantially straight line, the helical slot having an opening for facilitating fluid flow between chambers; thereby as the control valve moves along the substantially straight line the vane position within the cavity is controlled.    
     
     
         2 . The phaser of  claim 1 , wherein the vane has a vane cavity disposed to have at least one check valve placed therein.  
     
     
         3 . The phaser of  claim 1  further comprises means for limiting the control valve to move along the substantially straight line.  
     
     
         4 . The phaser of  claim 1  further comprising a sprocket rigidly affixed to the housing and disposed to rotate in unison with the housing.  
     
     
         5 . The phaser of  claim 1  further comprising a back plate rigidly affixed onto the housing and rotor for containing control fluid within the phaser.  
     
     
         6 . A method comprising the steps of: 
 providing a housing having at least one cavity therein;    providing a rotor having at least one vane oscillating within the at least one cavity of the housing, the rotor being disposed to engage the housing, or rotate relative the housing, the cavity being divided into an advance chamber and a retard chamber by the at least one vane;    providing a control valve disposed to translationally move within an opening of the rotor along a substantially straight line, the control valve having at least two openings for selectively controlling fluid flow among a set of passages within the phaser for control fluid to occupy either the advance chamber or the retard chamber;    at the outer surface of the control valve, providing a helical slot having at least one side, wherein a non-zero angle exists between the at least one side and the substantially straight line, the helical slot having an opening for facilitating fluid flow between chambers; and    translationally moving the control valve along the substantially straight line a predetermined distance for controlling the position of the vane within the cavity of the housing.    
     
     
         7 . The method of  claim 6 , wherein the vane has a vane cavity disposed to have at least one check valve placed therein.  
     
     
         8 . The method of  claim 6  further comprising the step of providing a means for limiting the control valve to move along the substantially straight line.  
     
     
         9 . The method of  claim 6  further comprising the step of providing a sprocket rigidly affixed to the housing and disposed to rotate in unison with the housing.  
     
     
         10 . The method of  claim 6  further comprising providing a back plate rigidly affixed onto the housing and rotor for containing control fluid within the phaser.