Vehicle suspension damper

Abstract

A vehicle suspension damper for providing a variable damping rate. The vehicle suspension damper comprises a first damping mechanism having a variable first threshold pressure, a second damping mechanism having a second threshold pressure, and a compressible chamber in communication with a damping fluid chamber, wherein the second damping mechanism is responsive to a compression of said compressible chamber.

What we claim is: 
     
         1 . A vehicle suspension damper for providing a variable damping rate, said vehicle suspension damper comprising:
 a damping fluid chamber, said damping fluid chamber having a first portion and a second portion;   a damping fluid disposed in said damping fluid chamber;   a damping fluid flow path between said first portion of said damping fluid chamber and said second portion of said damping fluid chamber;   a first damping mechanism fluidically coupled to said damping fluid flow path, said first damping mechanism affecting flow of said damping fluid through said damping fluid flow path, said first damping mechanism comprising:
 an aperture fluidically coupled to said damping fluid flow path; and 
 a damping adjustment valve coupled to said aperture to control flow of said damping fluid through said aperture, said damping adjustment valve adjustable external to said damping fluid chamber: 
   a second damping mechanism fluidically coupled to at least a portion of said damping fluid flow path such that said first damping mechanism and said second damping mechanism both affect flow of said damping fluid through a common portion of said damping fluid flow path, said second damping mechanism affecting flow of said damping fluid through said at least a portion of said damping fluid flow path, said second damping mechanism comprising:
 a variable damper enclosing a fillable chamber, said variable damper comprising:
 a valve inner; and 
 a movable valve outer to engage portions of said valve inner, said fillable chamber creates a gap between said valve inner and said movable valve outer such that said valve inner and said movable valve outer enclose said fillable chamber, and such that fluid does not flow out of said fillable chamber, said movable valve outer selectively obstructs said second flow path in response to a state of a compression of said vehicle suspension damper, said fillable chamber having a fillable chamber pressure introduced therein during assembly of said variable damper; 
 
   a shaft movably disposed within said damping fluid chamber, said shaft movable into said damping fluid chamber during a compression stroke of said vehicle suspension damper, during which time a differential pressure between said damping fluid and said fillable chamber drives said movable valve outer and said valve inner more tightly together axially, to cause said second damping mechanism to increase a restriction of flow of said damping fluid through said at least a portion of said damping fluid flow path, and create an increase in compressive damping force for said vehicle suspension damper; and   a compressible chamber, wherein upon said compression of said vehicle suspension damper, said shaft enters said first fluid chamber to displace and reduce an available fluid volume, whereby a combination of an incursion of said shaft and said damping fluid remaining in said first fluid chamber compresses a compressible chamber and increases the volume of said first fluid chamber, a pressure and volume of said compressible chamber being in a compressed or further compressed state such that a static pressure of said damping fluid is increased functionally with change of a position in a compression stroke of said vehicle suspension damper.