Shock absorber with frequency dependent passive valve

Patent metadata

Field	Value
Publication number	US-9500255-B2
Application number	US-201414193102-A
Country	US
Kind code	B2
Filing date	Feb 28, 2014
Priority date	Feb 28, 2014
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

A shock absorber has a pressure tube with a piston assembly slidably disposed within the pressure tube and attached to a piston rod. The piston assembly divides the pressure tube into an upper working chamber and a lower working chamber. The piston assembly includes a frequency dependent valve assembly attached to the piston rod which defines a housing attached to the piston rod and a spool valve assembly. The spool valve assembly includes a spool valve and first and second bypass valve assemblies that control fluid flow through bypass passage that bypasses the piston assembly.

First claim

What is claimed is:

1. A shock absorber comprising:
a pressure tube defining a fluid chamber for containing a working fluid;
a piston assembly disposed within said pressure tube, said piston assembly dividing said fluid chamber into an upper working chamber and a lower working chamber;
a piston rod projecting out of said pressure tube and having a bore extending therethrough, said piston assembly being attached to said piston rod;
a frequency dependent valve assembly attached to said piston rod, said frequency dependent valve assembly comprising:
a housing attached to said piston rod, said housing defining a fluid cavity;
a spool valve assembly disposed within said fluid cavity, said spool valve assembly including a spool valve having a bore extending completely therethrough and a radially extending annular flange, said annular flange separating said fluid cavity into an upper chamber and a lower chamber, and a compression bypass valve assembly; wherein

movement of said spool valve within said fluid cavity controls an amount of fluid pressure required to open said compression bypass valve assembly, and thus allows a flow of said working fluid through said bore of said spool valve, completely bypassing said upper and lower chambers of said fluid cavity, and through said bore of said piston rod during a first frequency movement of said shock absorber, while at least substantially interrupting flow of said working fluid during a second frequency movement of said shock absorber which is of a lower frequency than said first frequency movement.

2. The shock absorber according to claim 1 , wherein said frequency dependent valve assembly controls fluid flow from said lower working chamber to said upper working chamber.

3. A shock absorber, comprising:
a pressure tube defining a fluid chamber for containing a working fluid;
a piston assembly disposed within said pressure tube, said piston assembly dividing said fluid chamber into an upper working chamber and a lower working chamber;
a piston rod projecting out of said pressure tube and having a bore extending therethrough, said piston assembly being attached to said piston rod;
a frequency dependent valve assembly attached to said piston rod, said frequency dependent valve assembly comprising:
a housing attached to said piston rod, said housing defining a fluid cavity;
a first spool valve assembly disposed within said fluid cavity, said first spool valve assembly including a first spool valve having a first bore extending completely therethrough and a radially extending first annular flange, said first annular flange helping to define an upper chamber in said fluid cavity, and a compression bypass valve assembly; wherein

movement of said first spool valve within said fluid cavity controls an amount of fluid pressure required to open said compression bypass valve assembly, and thus allows a flow of said working fluid through said first bore of said first spool valve, completely bypassing said upper chamber of said fluid cavity, and through said first bore of said piston rod during a first frequency movement of said shock absorber, while at least substantially interrupting flow of said working fluid during a second frequency movement of said shock absorber which is of a lower frequency than said first frequency movement;
a second spool valve assembly disposed within said fluid cavity, said second spool valve assembly including a second spool valve having a radially extending second annular flange which helps to define an upper chamber within said fluid cavity; and a second bore therethrough;
rebound bypass valve assembly operably associated with said second spool valve assembly; and
wherein movement of said second spool valve within said fluid cavity controls an amount of fluid pressure required to open said rebound bypass valve assembly; and
wherein said working fluid flowing through said second spool valve completely bypasses said lower chamber.

4. The shock absorber according to claim 3 , wherein said frequency dependent valve assembly controls fluid flow from said lower working chamber to said upper working chamber.

5. The shock absorber according to claim 3 , wherein said frequency dependent valve assembly controls fluid flow from said upper working chamber to said lower working chamber.

6. The shock absorber according to claim 1 , wherein said bore of said piston rod defines a fluid passage extending between said upper working chamber and said fluid cavity.

7. The shock absorber according to claim 1 , wherein said spool valve defines a fluid passage in direct fluid communication with said compression bypass valve assembly.

8. A shock absorber comprising:
a pressure tube defining a fluid chamber for containing a working fluid;
a piston assembly disposed within said pressure tube, said piston assembly dividing said fluid chamber into an upper working chamber and a lower working chamber;
a piston rod projecting out of said pressure tube and having a bore extending therethrough, said piston assembly being attached to said piston rod;
a frequency dependent valve assembly attached to said piston rod, said frequency dependent valve assembly comprising:
a housing attached to said piston rod, said housing defining a fluid cavity;
a spool valve assembly disposed within said fluid cavity, said spool valve assembly including a spool valve having a bore extending completely therethrough and a radially extending annular flange, said annular flange separating said fluid cavity into an upper chamber and a lower chamber, a compression bypass valve assembly and a rebound bypass valve assembly; wherein

movement of said spool valve within said fluid cavity controls an amount of fluid pressure required to open both said rebound bypass valve assembly and said compression bypass valve assembly and thus allows a flow of said working fluid through said bore of said first spool valve, completely bypassing said upper and lower chambers of said fluid cavity, and through said bore of said piston rod during a first frequency movement of said shock absorber, while at least substantially interrupting flow of said working fluid during a second frequency movement of said shock absorber which is of a lower frequency than said first frequency movement.

9. The shock absorber according to claim 8 , wherein said frequency dependent valve assembly controls fluid flow from said upper working chamber to said lower working chamber.

10. The shock absorber according to claim 9 , wherein said frequency dependent valve assembly controls fluid flow from said lower working chamber to said upper working chamber.

11. The shock absorber according to claim 8 , wherein said bore of said spool valve defines a fluid passage in direct fluid communication with said compression bypass valve assembly.

12. The shock absorber according to claim 11 , wherein said fluid passage defined by said bore of said spool valve is in direct fluid communication with said rebound bypass valve assembly.

13. The shock absorber according to claim 8 , wherein said bore of said spool valve defines a fluid passage in direct fluid communication with said rebound bypass valve assembly.

14. The shock absorber according to claim 8 , wherein said compression bypass valve assembly includes a first interface and a first valve disc, said frequency dependent valve assembly further comprising a first spring biasing said first valve disc into engagement with said first interface, a first biasing chamber being defined by said first interface and said first valve disc.

15. The shock absorber according to claim 14 , wherein said bore of said

Assignees

• Tenneco Automotive Operating Co Inc

Inventors

• Nowaczyk Mark
• Bismans Gunther

Classifications

• F16F9/512 Primary

  Means responsive to load action, {i.e. static load} on the damper or {dynamic} fluid pressure {changes} in the damper, {e.g. due to changes in velocity (F16F9/504, F16F9/516 take precedence; non-automatic damper adjustment from a distance using servo control, the servo pressure being created by the flow of damping fluid F16F9/465; self-pumping fluid springs in vehicle suspensions B60G17/044)} · CPC title