US 7,320,388 B2 | ||
Stroke dependent damping | ||
Simon A de Molina, Marche-les-Dames (Belgium) | ||
Assigned to Tenneco Automotive Operating Company Inc., Lake Forest, Ill. (US) | ||
Filed on Sep. 15, 2003, as Appl. No. 10/662,547. | ||
Prior Publication US 2005/0056501 A1, Mar. 17, 2005 | ||
Int. Cl. F16F 9/50 (2006.01) |
U.S. Cl. 188—287 [188/281] | 10 Claims |
1. A two-stage shock absorber comprising:
a pressure tube defining a chamber;
a piston rod assembly disposed within said chamber;
a valve assembly fixably attached to said piston rod assembly and slidably engaging said pressure tube within said chamber,
said valve assembly dividing said chamber into an upper and a lower working chamber, said valve assembly providing a first
and a second fluid flow path between said upper and lower working chambers completely through said valve assembly, said first
and second flow paths of said valve assembly being totally separate from one another; and
a sleeve slidably disposed on said piston rod assembly, said piston rod assembly defining a passage and a plurality of holes
through said piston rod assembly, the plurality of holes being arranged in a helical spiral formation to create a third separate
and distinct flow path extending between said upper and lower working chambers, said sleeve being operable to progressively
close said third flow path by sequentially covering said plurality of holes when movement of said piston rod assembly exceeds
a specified distance, said progressive closing of said third flow path providing a progressively higher resistance to the
movement of said piston rod assembly, said sleeve being operable to simultaneously cover all of said plurality of holes to
fully close said third flow path.
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