Shock absorber piston rod seal assembly with belleville washer

Claim 1

A direct acting hydraulic shock absorber comprising: a pressure cylinder tube; valved piston means concentrically supported within said pressure cylinder tube for the regulation of hydraulic fluid flow therethrough; a reservoir tube concentrically around said pressure cylinder tube; a piston rod attached to said piston means for reciprocating said piston means in said pressure cylinder tube; said piston rod extending axially outward from said pressure cylinder tube; a piston rod guide within one end of said pressure cylinder tube and around said piston rod for positioning said piston rod concentrically within said pressure cylinder tube; an end cap encircling said piston rod and spaced axially outward from said piston rod guide to form an annular space therebetween; an annular piston rod seal in said space having a wearable cylindrical surface adapted to sealingly contact said piston rod to prevent leakage of hydraulic fluid therebetween; said piston rod seal further having a flat end surface adapted to bear against said end cap; a conical end surface on the opposite end of said piston rod seal; an annular loading riNg encircling and radially spaced from said piston rod and having a conical end surface adapted to contact said conical end surface of said piston rod seal for transforming axial forces on said loading ring into radial forces on said piston rod seal to maintain said wearable cylindrical seal surface against said piston rod; an annular washer shaped spring supported at its outer peripheral edge by said piston rod guide and contacting said loading ring at its inner peripheral edge; said annular washer spring having a non-planar configuration with its inner peripheral edge axially outward from its outer peripheral edge and said piston means when unstressed during assembly of said shock absorber prior to contact with said loading ring; said annular washer spring having a distorted configuration with its inner peripheral edge axially inward from its outer peripheral edge and said end cap when stressed after final assembly of said shock absorber whereby said stressed washer spring exerts a substantially constant axial force on said loading ring producing a constant radial force on said piston rod seal as said wearable cylindrical surface wears by frictional contact with said piston rod.