Valve assembly and reduced harshness shock absorber embodying the same

A shock absorber comprising:

• a cylinder member;
• a piston assembly having an axis aligned with the axis of said cylinder member;
• a piston rod fixed to said piston assembly and extending axially therefrom outwardly of one end of said cylinder member disposed upwardly when said shock absorber is operatively mounted;
• an intermediate tube surrounding said cylinder member, the interior of which defines with the exterior of said cylinder member an annular reservoir chamber;
• the portion of said cylinder member above the piston assembly constituting a rebound chamber the volume of which is variable depending upon the position of said piston assembly within said cylinder member;
• a base and end cap assembly fixedly connecting the lower end of said cylinder member and said intermediate tube so as to define the lower end of a compression chamber within said cylinder member the upper end of which is defined by the piston assembly and the volume of which is variable depending upon the position of said piston assembly within said cylinder member;
• hydraulic fluid filling said rebound and compression chambers and partially filling said reservoir chamber;
• restricted fluid flow control means on the exterior periphery of said piston assembly cooperable with the interior periphery of said cylinder member providing for controlled restricted flow of hydraulic fluid between said compression chamber and said rebound chamber during the movement of said piston member within said cylinder member;
• base valve means in said base and end cap assembly providing for controlled flow of hydraulic fluid from said compression chamber to said reservoir chamber during a compression movement of said piston member toward said other end of said cylinder member;
• replenishing valve means in said base and end cap assembly for enabling hydraulic fluid to flow from said reservoir chamber to said compression chamber during a rebound movement of said piston assembly toward said one end of said cylinder member;
• said piston assembly having a central opening therein communicating at its upper end with said rebound chamber and having at its lower end a downwardly facing annular valve seat surrounding the lower end of said opening;
• a rebound control disk valve disposed below said annular valve seat, said disk valve operable for movement into and out of sealing engagement with said valve seat;
• and
• spring means carried by said piston assembly resiliently urging said disk valve into engagement with said valve seat, the improvement wherein:
• said rebound control disk valve includes normally open valve means formed interiorly in said disk valve and operable (1) in an open position to permit relatively unrestricted flow of hydraulic fluid through said disk valve between said chambers when said disk valve is engaged with said valve seat and (2) in a closed position to restrict flow of hydraulic fluid through said disk valve permitting said disk valve to control the fluid movement between said chambers by movement of the disk valve relative to said valve seat.