Jounce bumper assembly for vehicle suspension strut

A jounce bumper assembly for a vehicle suspension strut comprising a shock absorber having an outer support casing and a piston rod extending out of the casing upper end cover plate, means connecting said casing to the vehicle unsprung mass, an upper mount connecting the upper end of said piston rod to the vehicle sprung mass, said upper mount including a transverse portion having a central aperture therein receiving said piston rod therethrough in a spaced concentric manner, and means connecting the upper end of said piston rod to said sprung mass, said jounce bumper assembly comprising:

• a rigid inverted cup-shaped shell member and a molded flexible elastomeric sleeve member;
• said cup-shaped shell member having a transverse upper closed end portion and a right cylindrical shaped outer side wall portion concentric with said piston rod;
• said shell member upper closed end portion formed with an upwardly extending neck portion of an external size and shape to closely fit within said upper mount aperture;
• said neck portion defining an internal piston rod passage including locking means adapted for retaining said shell neck portion within said mount aperture;
• said shell side wall portion formed with a plurality of slots positioned adjacent its upper closed end;
• said elastomeric sleeve member defining a cylindrical shaped annular hollow lower sleeve portion and an upper cap portion, said lower sleeve portion concentrically encircling the piston rod and radially spaced intermediate said shell member cylindrical side wall portion and said piston rod;
• said sleeve portion having control ring means embedded therein adjacent its lower end;
• said sleeve member upper cap portion formed with a central aperture receiving said piston rod therethrough, said cap portion molded with a plurality of integral resilient locking tabs around its outer periphery, each said locking tab sized for reception in an associated aligned slot such that upon said piston rod being inserted through said cap portion central aperture said sleeve member cap portion is positively retained in said shell member;
• said sleeve portion defining a predetermined height such that its lower end face is positioned a determined axial distance above the casing upper end cover plate with said strut in its neutral vehicle height position;
• whereby upon said sleeve portion lower end face being initially impacted the resulting impact is substantially absorbed by the column effect of said sleeve portion assisted by said embedded control ring means providing a high initial spring rate and thus high early damping of the shock jounce strokes with minimal axial compression travel of the piston rod;
• and
• upon said sleeve portion being further compressed the resultant stress causes an intermediate portion of said sleeve to buckle outwardly, wherein such outward movement is restricted in a controlled manner by said shell member cylindrical outer side wall thereby achieving increased damping adjacent the end of said piston rod jounce stroke.