Patent ID: 6343677
Filing Date: 2002-02-05
Classification: B60G,F16F

Abstract:
In a shock absorber capable of providing selectively adjustable damping forces, the shock absorber including:an inner cylinder assembly defining an internal chamber that has a rod end and a closed end and that has a central longitudinal axis extending between the rod and closed ends; a piston assembly that is slidably mounted for reciprocal, axial movement within the internal chamber in a compression stroke direction and in a recoil stroke direction and that defines a rebound compartment adjacent the rod end of the inner cylinder and a compression compartment adjacent the closed end of the inner cylinder, with the volumes of the rebound and compression compartments varying in accordance with the position of the piston assembly in the internal chamber, with the rebound and compression compartments being adapted to be filled with fluid, and with the piston assembly defining one axial end of the compression compartment; a piston rod that is connected to the piston assembly and that extends from the rod end of the internal chamber; a closure assembly that closes the rod end of the internal chamber and that slidably and sealingly engages about the piston rod; a fluid reservoir compartment that is in fluid communication with the rebound and compression compartments; a compression head assembly that is in the internal chamber adjacent the closed end and that defines the other axial end of the compression compartment, the compression assembly including a first surface adjacent to the compression compartment, a second surface adjacent the closed end and a compression flow passage, with the compression flow passage having an inlet end and an outlet end, with the inlet end of the compression flow passage being adjacent the first surface, with the outlet end of the compression flow passage being adjacent the second surface, with the compression flow passage extending between the first surface and the second surface so as to permit fluid flow from the compression compartment to the reservoir compartment when the piston assembly moves in a compression stroke direction and with a valve seat being defined adjacent the outlet end, the improvement comprising: an end cap assembly including a solenoid subassembly that has a bobbin subassembly which when energized, creates a electromagnetic field; that has a fixed, magnetizable core which has a first surface adjacent the second surface of the compression head assembly and which has a second surface adjacent the closed end of the shock absorber; that has a plunger subassembly which is axially movable with respect to the core, and which has a push rod which has a magnetizable plunger connected to and movable with the push rod, with a first end of the push rod being adapted to contact the valve seat so as to prevent fluid flow through the compression flow passage of the compression head assembly when the plunger subassembly is moved to a first axial position and being adapted to be spaced from the valve seat a predetermined distance so as to permit fluid flow through the compression flow passage when the plunger subassembly is moved to a second axial position; the plunger subassembly being disposed, with respect to the bobbin subassembly and the core, so that upon energization of the bobbin subassembly, the plunger subassembly is moved to the first axial position and so that an air gap, having a predetermined dimension, exists between a portion of the second surface of the core and an axially adjacent portion of the plunger when the plunger subassembly is in the first axial position.