Low leak poppet solenoid

Abstract

A dual poppet low leak variable bleed solenoid valve, including a solenoid portion with an adjustable end cap disposed through the solenoid. Exhaust ports are disposed about the end cap. A hydraulic portion has a valve housing that is connectable to the solenoid portion. The hydraulic portion has a control volume formed within, and a supply port is connected through the valve housing. A valve shaft is slidably disposed through the solenoid portion and extends longitudinally into the hydraulic portion. A first end of the valve shaft terminates in the solenoid portion forming a primary valve, and a second end of the valve shaft terminates in the hydraulic portion forming a secondary valve. The valve shaft further has a hollow channel disposed through the valve shaft to allow the passage of a fluid medium between the first end and second end of the valve shaft.

1 . A solenoid valve comprising:
 a solenoid portion having a housing encasing a bobbin with a coil wound thereon and an exhaust passage disposed through an end of said housing;   a hydraulic portion having a valve housing connectable to said solenoid portion and a control volume connected to said hydraulic portion;   a supply port connected through said valve housing of said hydraulic portion;   a valve shaft including an armature slidably disposed through said solenoid portion and said bobbin being annularly positioned about said armature, said valve shaft extending from said solenoid portion into said hydraulic portion, said valve shaft including a first end terminating positioned adjacent in said solenoid portion and a second end positioned adjacent said hydraulic portion;   a first valve located at the first end of said valve shaft; and   a second valve located at the second end of said valve shaft, wherein when said valve shaft is moved in a first direction the secondary valve moves toward an open position and said primary valve moves toward a closed position and when moved in a second direction the secondary valve moves toward a closed position and said primary valve moves toward an open position.   
   
   
       2 . The solenoid valve of  claim 1  further comprising a hollow channel disposed through said valve shaft to allow the fluid communication between said secondary valve and said primary valve. 
   
   
       3 . The solenoid valve of  claim 2  wherein said hollow channel may provide viscous dampening of said valve shaft to improve the stability of the solenoid valve. 
   
   
       4 . The solenoid valve of  claim 1  further comprising an adjustable end cap disposed through said housing of said solenoid wherein said exhaust ports are disposed about said end cap. 
   
   
       5 . The solenoid valve of  claim 4  wherein said primary valve is formed of a primary poppet formed about said first end of said valve shaft and a primary valve seat formed in said end cap adjacent said primary poppet;
 said secondary valve being comprised of a secondary poppet formed about said second end of said valve shaft and a secondary valve seat contained within said hydraulic portion and having an aperture extending through said secondary valve seat, wherein said secondary valve seat is positioned between said control volume and said supply port.   
   
   
       6 . The dual poppet low leak variable bleed solenoid valve of  claim 1  further comprising:
 a pole piece annularly disposed in said solenoid portion adjacent said bobbin, wherein said pole piece has a reduced inner diameter flange and is configured to align with and slidably circumscribe said armature, wherein said armature is circumscribed by said bobbin and coil so that said armature and said valve shaft slide about the longitudinal axis of said valve shaft in response to the energization of said solenoid portion.   
   
   
       7 . The solenoid valve of  claim 6  further comprising:
 one or more lower bearings disposed between said valve shaft and said housing, wherein said one or more lower bearings function to facilitate the sliding of said valve shaft; and   a spring configured about said valve shaft and extending between said armature and said one or more upper bearings, wherein said solenoid portion is de-energized said spring applies force to said armature to slide said valve shaft so said primary valve is in the open position and said secondary valve is in the closed position.   
   
   
       8 . A solenoid valve comprising:
 a solenoid portion having a housing encasing a coil assembly and an adjustable end cap disposed though said housing said end cap including surfaces forming exhaust ports disposed about said end cap;   a hydraulic portion having a valve housing connectable to said solenoid portion and a control volume formed within said hydraulic portion;   a supply port connected through said valve housing of said hydraulic portion;   a valve shaft slidably disposed through said solenoid portion so said bobbin is annularly positioned about said valve shaft and extending from said solenoid portion into said hydraulic portion, wherein a first end of said valve shaft terminates in said solenoid portion and has a primary poppet formed about said first end, and a second end of said valve shaft terminates in said hydraulic portion and has a secondary poppet formed about said second end;   a hollow channel disposed though said valve shaft to allow the passage of a medium between said first end and said second end of said valve shaft;   a primary poppet seat contained within said solenoid portion, said primary valve seat being formed in said end cap adjacent the primary poppet of said valve shaft;   a secondary valve seat contained within said hydraulic portion and having an aperture extending through the seat, wherein said secondary valve seat is positioned between said control volume and said supply port;   a pole piece is annularly disposed in said solenoid portion adjacent said bobbin, wherein said pole piece has a reduced inner diameter flange; and   an armature attached to said valve shaft, said armature configured to align with and slidably inscribe said reduced inner diameter flange of said pole piece, wherein said armature circumscribed by said bobbin and coil and said armature and said valve shaft is configured to slide longitudinally in response to the energization of said solenoid portion.   
   
   
       9 . The solenoid valve of  claim 8  further comprising a spring configured about said valve shaft, wherein said spring is biased to move said secondary poppet in a direction to contact said secondary valve seat placing said dual poppet low leak solenoid valve in a normally closed or normally high pressure position. 
   
   
       10 . The solenoid valve of  claim 8  further comprising a spring configured about said valve shaft, wherein said spring is biased to move said primary poppet in a direction to contact said primary valve seat, placing said valve in a normally opened or normally low pressure position. 
   
   
       11 - 16 . (canceled) 
   
   
       17 . A valve comprising:
 a motorized portion having a housing;   a hydraulic portion having a housing connectable to said housing of said motorized portion;   a valve shaft disposed though said hydraulic portion and extending into said motorized portion and a hollow channel extending through said valve shaft, wherein said valve shaft and said hollow channel have a first end terminating in said motorized portion and a second end terminating in said hydraulic portion;   a first valve located at said first end of said hollow channel, wherein when said valve shaft is moved in a first direction the first valve moves toward a closed position and when said valve shaft is moved in a second direction the first valve moves toward an open position.   
   
   
       18 . The valve of  claim 17  further comprising a second valve located at a second end of said valve shaft, wherein when said valve shaft is moved in said first direction said second valve moves toward an open position and when said valve shaft is moved in a second direction said second valve moves toward a closed position. 
   
   
       19 . The valve of  claim 18  wherein said first valve is formed of a primary first poppet formed about said first end of said valve shaft and a primary valve seat formed in an end cap adjacent said primary first poppet; and
 said second valve having a second poppet formed about said second end of said valve shaft and a second valve seat contained within said hydraulic portion and having an aperture extending through said second valve seat.   
   
   
       20 . The valve of  claim 18  further comprising a spring configured about said valve shaft, wherein said spring is biased to move said valve shaft in said second direction. 
   
   
       21 - 39 . (canceled)