Proportional pressure control valve

Abstract

This invention generally concerns electronically controlled hydraulic valves for use in electro-hydraulically controlled transmissions. The proportional pressure control valve 20 includes a hollow cage 42 pierced by cage tank ports 52, cage clutch ports 54, and cage pump ports 56. The cage pump ports 56 receive fluid from a pump. The cage clutch ports 54 supply fluid to a hydraulic actuator. The cage tank ports 52 return fluid from the valve 20 to a tank from where fluid circulates back to the pump. Main spool 112 controls fluid flow between cage clutch ports 54 and cage pump ports 56 or cage tank ports 52. An electro-magnetically operated pilot valve regulates fluid pressure applied to a control pressure surface 138. A feedback pressure passage 126, having feedback restriction orifice 128, restrains the rate fluid flows between the cage clutch ports 54 and the feedback pressure surface 114.

1 .- 43 . (canceled)  
   
   
       44 . In a proportional pressure control cartridge valve that includes: 
 a hollow cage having an axial direction and a radial direction that includes a wall pierced by a pump port that is adapted for receiving hydraulic fluid from a pump at a pressure established by the pump, the wall also being pierced by a clutch port that is adapted for conducting pressurized hydraulic fluid to a hydraulic actuator, and the wall also being pierced by a tank port that is adapted for conducting hydraulic fluid to a tank;    the improvement comprising: 
 said clutch port and said tank port piercing said wall in a direction substantially parallel to said radial direction of said cage;  
 a spool having an axial direction and radial direction, said axial direction of said spool being substantially parallel to said axial direction of said cage and said radial direction of said spool being substantially parallel to said radial direction of said cage, said spool being adapted to fit snugly within the cage in which location the spool is moveable relative to the cage in a direction substantially parallel to the axial direction of said cage for controlling a flow of hydraulic fluid passing between the clutch port in the cage and either the pump port or the tank port in the cage, the spool including a control pressure surface to which pressure may be applied for urging the spool to move within the cage to a position in which the spool allows a flow of hydraulic fluid between the pump port and the clutch port, the spool also including a feedback pressure surface to which pressure may be applied for urging the spool to move within the cage to a position in which the spool allows a flow of hydraulic fluid between the clutch port and the tank port, said spool further having a pilot valve supply passage formed therein that receives a flow of hydraulic fluid from the pump port of said cage and conducts said flow of hydraulic fluid within said pilot valve supply passage of said spool through a control flow restriction orifice toward said control pressure surface;  
 a control pressure chamber located within the cage for receiving hydraulic fluid under pressure and applying the pressure of the hydraulic fluid to the control pressure surface of the spool;  
 an electromagnetically operated pilot valve that receives a flow of hydraulic fluid passing through the pilot valve supply passage of said spool for supplying a regulated pressure of hydraulic fluid to the control pressure chamber responsive to an electrical control signal;  
 a feedback pressure chamber located within the cage for receiving hydraulic fluid at a pressure and applying the pressure of the hydraulic fluid to the feedback pressure surface of the spool; and  
 a clutch port feedback pressure passage consisting of an aperture formed in the spool for conducting the hydraulic fluid through the spool between the clutch port in the cage and the feedback pressure chamber wherein at least a portion of said aperture in said spool of said clutch port feedback pressure passage has a sufficiently narrow portion formed within said aperture in said spool so as to restrain the rate at which hydraulic fluid is conducted between the clutch port in the cage and the feedback pressure chamber.  
   
   
   
       45 . The proportional pressure control cartridge valve of  claim 44  wherein the narrowest portion of said clutch port feedback pressure passage that restrains the rate at which hydraulic fluid may be conducted between the clutch port in the cage and the feedback pressure chamber is between approximately 0.020 inches and 0.040 inches in diameter.  
   
   
       46 . The proportional pressure control cartridge valve of  claim 45  further comprising a control pressure chamber outlet through which hydraulic fluid flows from said control pressure chamber.  
   
   
       47 . The proportional pressure control cartridge valve of  claim 46  wherein said electromagnetically operated pilot valve restrains the rate at which hydraulic fluid flows from said control pressure chamber through the control pressure chamber outlet, and thereby regulates the pressure of the hydraulic fluid within said control pressure chamber.  
   
   
       48 . The proportional pressure control cartridge valve of  claim 47  further comprising a control pressure flow return passage for conducting the hydraulic fluid that flows out of said control pressure chamber through the control pressure chamber outlet to the tank port of the valve.  
   
   
       49 . The proportional pressure control cartridge valve of  claim 44  further comprising a biasing means acting upon said feedback pressure surface of said spool in the axial direction of said spool in a manner that urges said spool to move in a direction substantially parallel to the axial direction of said cage toward said control pressure chamber.  
   
   
       50 . The proportional pressure control cartridge valve of  claim 49  wherein said biasing means is a compression spring acting upon said feedback pressure surface.  
   
   
       51 . The proportional pressure control cartridge valve of  claim 44  wherein a biasing means acting upon said feedback pressure surface supplies a biasing pressure to said spool urging said spool to move in a direction substantially parallel to the axial direction of a said cage to a position in which the spool allows the flow of hydraulic fluid between the clutch port and the tank port.  
   
   
       52 . The proportional pressure control cartridge valve of  claim 44  wherein a compression spring acting upon said feedback pressure surface supplies a biasing pressure to said spool urging said spool to move in a direction substantially parallel to the axial direction of a said cage to a position in which the spool allows the flow of hydraulic fluid between the clutch port and the tank port.  
   
   
       53 . The proportional pressure control cartridge valve of  claim 44  wherein said control flow restriction orifice restrains the rate at which hydraulic fluid may flow between the pump port and the control pressure chamber.  
   
   
       54 . The proportional pressure control cartridge valve of  claim 44  further comprising a removable screen located in said pilot valve supply passage between said pump port and said control flow restriction orifice.  
   
   
       55 . The proportional pressure control cartridge valve of  claim 54  further comprising a control pressure flow return passage for conducting the hydraulic fluid flowing out of said control pressure chamber through the control pressure chamber outlet to the tank port of the valve.  
   
   
       56 . In a proportional pressure control cartridge valve that includes: 
 a hollow cage having an axial direction and a radial direction that includes a wall pierced by a pump port that is adapted for receiving hydraulic fluid from a pump at a pressure established by the pump, the wall also being pierced by a clutch port that is adapted for conducting pressurized hydraulic fluid to a hydraulic actuator, and the wall also being pierced by a tank port that is adapted for conducting hydraulic fluid to a tank;    the improvement comprising: 
 said clutch port and said tank port piercing said wall in a direction substantially parallel to said radial direction of said cage;  
 a spool having an axial direction and a radial direction, said axial direction of said spool being substantially parallel to said axial direction of said cage and said radial direction of said spool being substantially parallel to said radial direction of said cage, said spool being adapted to fit snugly within the cage in which location the spool is moveable relative to the cage in a direction substantially parallel to the axial direction of said cage for controlling a flow of hydraulic fluid between the clutch port in the cage and either the pump port or the tank port in the cage, said spool having a first axial end and a second axial end, the spool including a control pressure surface at said first axial end of said spool to which pressure may be applied for urging the spool to move within the cage in an axial direction toward said second axial end of said spool to a position in which the spool allows a flow of hydraulic fluid between the pump port and the clutch port, the spool also including a feedback pressure surface at said second end of said spool to which pressure may be applied for urging the spool to move within the cage in an axial direction toward said first axial end of said spool to a position in which the spool allows a flow of hydraulic fluid between the clutch port and the tank port, said spool further having a pilot valve supply passage formed in said spool and having an opening for receiving a flow of hydraulic fluid from the pump port of said cage and conducting said flow of hydraulic fluid within said pilot valve supply passage of said spool toward said first axial end of said spool;  
 a control pressure chamber located within the cage adjacent said control pressure surface for receiving hydraulic fluid under pressure and applying the pressure of the hydraulic fluid to the control pressure surface of the spool;  
 an electromagnetically operated pilot valve that receives a flow of hydraulic fluid passing through the pilot valve supply passage of said spool for supplying a regulated pressure of fluid to the control pressure chamber responsive to an electrical control signal;  
 a feedback pressure chamber located within the cage adjacent said feedback pressure surface for receiving hydraulic fluid at a pressure and applying the pressure of the hydraulic fluid to the feedback pressure surface of the spool; and  
 a clutch port feedback pressure passage consisting of an aperture formed in the spool for conducting the hydraulic fluid through the spool between the clutch port and the feedback pressure chamber, wherein at least a portion of said clutch port feedback pressure passage has a sufficiently narrow portion formed within said aperture in said spool so as to restrain the rate at which hydraulic fluid is conducted between the clutch port in the cage and the feedback pressure chamber.  
   
   
   
       57 . The proportional pressure control cartridge valve of  claim 56  further comprising 
 a control pressure chamber outlet through which hydraulic fluid flows from said control pressure chamber;    a control pressure flow return passage for conducting the hydraulic fluid that flows out of said control pressure chamber through the control pressure chamber outlet to the tank port of the valve; and    said electromagnetically operated pilot valve restraining the rate at which hydraulic fluid flows from said control pressure chamber through the control pressure chamber outlet, and thereby regulating the pressure of the hydraulic fluid within said control pressure chamber.    
   
   
       58 . The proportional pressure control cartridge valve of  claim 57  wherein the narrowest portion of said clutch port feedback pressure passage that restrains the rate at which hydraulic fluid may be conducted between the clutch port in the cage and the feedback pressure chamber is between approximately 0.020 inches and 0.040 inches in diameter.  
   
   
       59 . The proportional pressure control cartridge valve of  claim 56  wherein said pilot valve supply passage conducts the flow of hydraulic fluid at said first axial end of said spool in a direction substantially parallel to the axial direction of said cage and supplies a control pressure flow of hydraulic fluid from the pump port to said control pressure chamber, said proportional pressure control cartridge valve further comprising: 
 a control flow restriction orifice in fluid communication with said pilot valve supply passage for restraining the flow rate of the control pressure flow of hydraulic fluid between said pump port and said control pressure chamber;    said control pressure chamber having a control pressure chamber outlet through which hydraulic fluid flows from said control pressure chamber;    said electronically operated pilot valve restraining the rate at which hydraulic fluid flows from said control pressure chamber through the control pressure chamber outlet, and thereby regulating the pressure of the hydraulic fluid within said control pressure chamber.    
   
   
       60 . The proportional pressure control cartridge valve of  claim 59  further comprising a control pressure flow return passage for conducting the hydraulic fluid that flows out of said control pressure chamber through the control pressure chamber outlet to the tank port of the valve.  
   
   
       61 . The proportional pressure control cartridge valve of  claim 59 , further comprising: 
 a removable screen between said opening of said spool and said control flow restriction orifice.    
   
   
       62 . The proportional pressure control cartridge valve of  claim 56  further comprising: 
 a compression spring supplying a biasing pressure to said feedback pressure surface of said spool that urges said spool to move within said cage in a direction toward the first axial end of said spool to a position in which the spool allows the flow of hydraulic fluid between the clutch port and the tank port.    
   
   
       63 . In a proportional pressure control cartridge valve that includes: 
 a hollow cage having an axial direction and a radial direction that includes a wall pierced by a pump port that is adapted for receiving hydraulic fluid from a pump at a pressure established by the pump, the wall also being pierced by a clutch port that is adapted for conducting pressurized hydraulic fluid to a hydraulic actuator, and the wall also being pierced by a tank port that is adapted for conducting hydraulic fluid to a tank;    the improvement comprising: 
 said clutch port and said tank port piercing said wall in a direction substantially parallel to said radial direction of said cage;  
 a spool having an axial direction and radial direction, said axial direction of said spool being substantially parallel to said axial direction of said cage and said radial direction of said spool being substantially parallel to said radial direction of said cage, said spool being adapted to fit snugly within the cage in which location the spool is moveable relative to the cage in a direction substantially parallel to the axial direction of said cage for controlling a flow of hydraulic fluid passing between the clutch port in the cage and either the pump port or the tank port in the cage, the spool including a control pressure surface to which pressure may be applied for urging the spool to move within the cage to a position in which the spool allows a flow of hydraulic fluid between the pump port and the clutch port, the spool also including a feedback pressure surface to which pressure may be applied for urging the spool to move within the cage to a position in which the spool allows a flow of hydraulic fluid between the clutch port and the tank port, said spool further having a pilot valve supply passage formed therein that receives a flow of hydraulic fluid from the pump port of said cage and conducts said flow of hydraulic fluid within said pilot valve supply passage of said spool through a control flow restriction orifice toward said control pressure surface;  
 a control pressure chamber located within the cage for receiving hydraulic fluid under pressure and applying the pressure of the hydraulic fluid to the control pressure surface of the spool;  
 an electromagnetically operated pilot valve that receives a flow of hydraulic fluid passing through the pilot valve supply passage of said spool for supplying a regulated pressure of hydraulic fluid to the control pressure chamber responsive to an electrical control signal;  
 a feedback pressure chamber located within the cage for receiving hydraulic fluid at a pressure and applying the pressure of the hydraulic fluid to the feedback pressure surface of the spool; and  
 a clutch port feedback pressure passage consisting of an aperture formed in the spool for conducting the hydraulic fluid through the spool between the clutch port in the cage and the feedback pressure chamber, and restraining the rate at which hydraulic fluid is conducted between the clutch port in the cage and the feedback pressure chamber.  
   
   
   
       64 . The proportional pressure control cartridge valve of  claim 63  further comprising a control pressure chamber outlet through which hydraulic fluid flows from said control pressure chamber.  
   
   
       65 . The proportional pressure control cartridge valve of  claim 64  wherein said electromagnetically operated pilot valve restrains the rate at which hydraulic fluid flows from said control pressure chamber through the control pressure chamber outlet, and thereby regulates the pressure of the hydraulic fluid within said control pressure chamber.  
   
   
       66 . The proportional pressure control cartridge valve of  claim 65  further comprising a control pressure flow return passage for conducting the hydraulic fluid that flows out of said control pressure chamber through the control pressure chamber outlet to the tank port of the valve.  
   
   
       67 . The proportional pressure control cartridge valve of  claim 63  further comprising a biasing means acting upon said feedback pressure surface of said spool in the axial direction of said spool in a manner that urges said spool to move in a direction substantially parallel to the axial direction of said cage toward said control pressure chamber.  
   
   
       68 . The proportional pressure control cartridge valve of  claim 67  wherein said biasing means is a compression spring acting upon said feedback pressure surface.  
   
   
       69 . The proportional pressure control cartridge valve of  claim 63  wherein a biasing means acting upon said feedback pressure surface supplies a biasing pressure to said spool urging said spool to move in a direction substantially parallel to the axial direction of said cage to a position in which the spool allows the flow of hydraulic fluid between the clutch port and the tank port.  
   
   
       70 . The proportional pressure control cartridge valve of  claim 63  wherein a compression spring acting upon said feedback pressure surface supplies a biasing pressure to said spool urging said spool to move in a direction substantially parallel to the axial direction of said cage to a position in which the spool allows the flow of hydraulic fluid between the clutch port and the tank port.  
   
   
       71 . The proportional pressure control cartridge valve of  claim 63  wherein said control flow restriction orifice restrains the rate at which hydraulic fluid may flow between the pump port and the control pressure chamber.  
   
   
       72 . The proportional pressure control cartridge valve of  claim 63  further comprising a removable screen located in said pilot valve supply passage between said pump port and said control flow restriction orifice.  
   
   
       73 . The proportional pressure control cartridge valve of  claim 72  further comprising a control pressure flow return passage for conducting the hydraulic fluid flowing out of said control pressure chamber through the control pressure chamber outlet to the tank port of the valve.