Shock absorber assembly

Abstract

A shock absorber assembly includes a motion damping means that is filled with a fluid in operation and has a pair of relatively moveable parts ( 12, 14 ) and valve means ( 26 ) permitting flow of the fluid between the parts. The parts comprise a first part ( 12 ) and a second part ( 14 ) in which the first part is receivable whereby the parts are arranged for relative retracting and extending movement during which fluid is forced through the valve means ( 26 ) at respective predetermined controlled flow rates so as to dampen the movement. The relatively moveable parts contain respective primary chambers ( 24, 29 ) for the fluid. The first part is substantially smaller in cross-section than the second part to define an intermediate chamber ( 52 ) about the first part within the second part. Lateral port means ( 56 ) communicates the intermediate chamber ( 52 ) and the primary chamber ( 24 ) of first part ( 12 ). The flows at respective predetermined controlled flow rates are limited to respective flows (i) directly from the primary chamber ( 24 ) of the first part ( 12 ) to the primary chamber ( 29 ) of the second part ( 14 ) and (ii) via the intermediate chamber ( 52 ) and lateral port means ( 56 ) from the primary chamber ( 29 ) of the second part ( 14 ) to the primary chamber ( 24 ) of the first part ( 12 ).

The invention claimed is: 
     
       1. A shock absorber assembly including: a motion damping means that is filled with a fluid in operation and has a pair of relatively moveable parts and valve means permitting flow of said fluid between said parts, said parts comprising a first part and a second part in which the first part is receivable whereby the parts are arranged for relative retracting and extending movement during which fluid is forced through said valve means at respective predetermined controlled flow rates so as to dampen said movement; wherein said relatively moveable parts contain respective primary chambers for said fluid and said first part is substantially smaller in cross-section cross section than said second part to define an intermediate chamber about the first part within the second part; and wherein there is the first part further included includes lateral port means communicating said intermediate chamber and said primary chamber of the first part; and wherein said flows at respective predetermined controlled flow rates are limited to respective flows (i) through a piston directly from the primary chamber of the first second part to the primary intermediate chamber of the second part and (ii) via from said intermediate chamber and through the lateral port means of the first part into the primary chamber of the first part, then through the piston from the primary chamber of the second first part to the primary chamber of the first second part; characterized in that said and wherein the valve means includes peripheral compression ports and a central at least one rebound port radially separated inwardly from the peripheral compression ports such that the differences in flow rates of said compression and rebound ports provides differential fluid flow rates for the compression and rebound stroke said relative retracting and extending movements of the first and second parts of said assembly. 
     
     
       2. A shock absorber assembly according to  claim 1  wherein said first and second parts comprise telescopically interengaged tubes respectively of relatively smaller and larger diameter. 
     
     
       3. A shock absorber assembly according to  claim 2  wherein said valve means is provided in a valve body fixed at an inner end of the tube comprising said first part. 
     
     
       4. A shock absorber assembly according to  claim 3  wherein said lateral port means comprises a plurality of spaced individual ports in said tube comprising said first part. 
     
     
       5. A shock absorber assembly according to  claim 3  wherein said lateral port means is positioned whereby, during said extending movement, the lateral port means is covered near the end of the movement, whereby fluid in said intermediate chamber cushions further extending movement. 
     
     
       6. A shock absorber assembly according to  claim 2  wherein said lateral port means comprises a plurality of spaced individual ports in said tube comprising said first part. 
     
     
       7. A shock absorber assembly according to  claim 6  wherein said lateral port means is positioned whereby, during said extending movement, the lateral port means is covered near the end of the movement, whereby fluid in said intermediate chamber cushions further extending movement. 
     
     
       8. A shock absorber assembly according to  claim 2  wherein said lateral port means is positioned whereby, during said extending movemnet, movement the lateral port means is covered near the end of the movement, whereby fluid in said intermediate chamber cushions further extending movement. 
     
     
       9. A shock absorber assembly according to  claim 1 , further including pressurized-gas cushioning means including structure defining a first cavity for storing a pressurized gas and a second cavity for storing a fluid under pressure, and a floating piston sealingly separating said cavities, wherein said second cavity is in fluid flow communication with said motion damping means. 
     
     
       10. A shock absorber assembly according to  claim 9 , wherein said movement is such that when said parts relatively extend, fluid is caused to flow from said second cavity of the pressurized-gas cushioning means to the damping means whereby gas pressure in said first cavity moves the floating piston to reduce the gas pressure in the first cavity, and when said parts relatively retract, fluid is caused to flow from the damping means to said second cavity whereby to move the floating piston to increase the gas pressure of the gas in the first cavity. 
     
     
       11. A shock absorber assembly according to  claim 10  wherein said first part of the motion damping means and said structure of the pressurized-gas cushioning means are integral whereby said second cavity and said primary chamber of the first part comprise a single chamber. 
     
     
       12. A shock absorber assembly according to  claim 10  wherein said pressurized gas cushioning means and said motion damping means are substantially separate units and a conduit is provided for said fluid flow communication between the motion damping means and said second cavity. 
     
     
       13. A shock absorber assembly according to  claim 9 , wherein said first part of the motion damping means and structure of the pressurized-gas cushoning cushioning means are integral whereby said second cavity and said primary chamber of the first part comprise a single chamber. 
     
     
       14. A shock absorber assembly according to  claim 13 , wherein said first part of the motion damping means and said structure of the pressurized-gas cushioning means are provided by a single tube. 
     
     
       15. A shock absorber assmebly assembly according to  claim 1 , wherein said pressurized-gas cushioning means and said motion damping means are sustantially substantially separate units and a conduit is provided for said flow communication between the motion damping means and said second cavity. 
     
     
       16. A shock absorber assembly according to  claim 15  wherein said conduit is between the primary chamber of the first part of the motion damping means and said second cavity. 
     
     
       17. A shock absorber assembly according to  claim 15  wherein said conduit is between the primary chamber of the second part of the motion damping means and said second cavity. 
     
     
       18. A shock absorber assembly according to  claim 1 , wherein the valve means is such that said respective predetermined controlled flow rates in the respective directions are different whereby to vary the damping characteristics according to whether said movement is relative retracting or extending movement. 
     
     
       19. A shock absorber assembly according to  claim 1  including respective shim packs in part determining said respective predetermined controlled flow rates and further determining the respective directions of flow. 
     
     
       20. A shock absorber assembly including:
 a motion damping means that is filled with a fluid in operation and has a pair of relatively moveable parts and valve means permitting flow of said fluid between said parts, said parts comprising a first part and a second part in which the first part is receivable whereby the parts are arranged for relative retracting and extending movement during which fluid is forced through said valve means at respective predetermined controlled flow rates so as to dampen said movement;   wherein said relatively moveable parts contain respective primary chambers for said fluid and said first part is substantially smaller in cross-section than said second part to define an intermediate chamber about the first part within the second part;   and wherein the first part further includes lateral port means communicating said intermediate chamber and said primary chamber of the first part; and   wherein said flows at respective predetermined controlled flow rates are limited to respective flows:
 (i) through a piston directly from the primary chamber of the second part to said intermediate chamber via an outer ring of compression ports in the piston and 
 (ii) from said intermediate chamber to the primary chamber of the second part via the lateral port means in the first part, the primary chamber of the first part and at least one rebound port in the piston, said at least one rebound port being radially separated inwardly from the outer ring of compression ports such that the differences in flow rates of said compression and rebound ports provide differential fluid flow rates for said relative retracting and extending movements of the first and second parts of said assembly. 
   
     
     
       21. A shock absorber assembly as claimed in claim 20, further comprising a pressurized-gas cushioning means. 
     
     
       22. A shock absorber assembly as claimed in claim 21, wherein the pressurized gas cushioning means is in fluid communication with the primary chamber of the second part, and wherein
 said fluid flow during said relative retracting movement of the first and second parts additionally comprises fluid flow from the primary chamber of the second part to the pressurized-gas cushioning means, and   said fluid flow during said relative extending movement of the first and second parts additionally comprises fluid flow from said pressurized gas cushioning means to the primary chamber of the second part.   
     
     
       23. A shock absorber assembly as claimed in claim 21, wherein the pressurized gas cushioning means is integral to the first part, and wherein
 said fluid flow during said relative retracting movement of the first and second parts additionally comprises fluid flow from the primary chamber of the second part to the pressurized-gas cushioning means via the outer ring of compression ports, the intermediate chamber and the lateral port means, and   said fluid flow during said relative extending movement of the first and second parts further comprises fluid flow from the pressurized gas cushioning means through the at least one rebound port to the primary chamber of the second part.   
     
     
       24. A shock absorber assembly as claimed in claim 20 wherein said valve means includes respective shim packs in part determining said respective predetermined controlled flow rates and further determining the respective directions of flow.