Gas spring

Assignee: Suspa Holding GmbH

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Quick Facts

Patent No.: US 7,073,642
App. No.: 10/922,105
Granted: Jul 11, 2006
Kind: B2

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Abstract

A gas spring comprises a cylindrical casing, in which a piston rod is guided for displacement concentric of a central longitudinal axis. A damping piston is mounted on the piston rod, dividing the interior of the casing into two sectional casing chambers. A filling of compressed gas is provided inside the casing. A damping device is provided for velocity-dependent damping of a motion of stroke of the damping piston and another damping device is provided for path-dependent damping of a motion of stroke of the damping piston. The result is a gas spring of excellently controllable stroke behaviour.

Claims (45)

1. A gas spring, comprising

a cylindrical casing ( 1 ) which has an inside wall ( 20 ), a central longitudinal axis ( 5 ), a bottom ( 2 ) and an end ( 4 ) opposite the bottom ( 2 );

a piston rod ( 6 ) which is concentric of the central longitudinal axis ( 5 ) and which is extended from the end ( 4 ) through a guide and seal unit ( 8 ) and out of the casing ( 1 ) ;

a damping piston ( 9 ) which is disposed on an end, inside the casing ( 1 ), of the piston rod ( 6 ), dividing the casing ( 1 ) into two sectional casing chambers ( 10 , 11 );

a filling of compressed gas inside the casing ( 1 );

a damping device ( 28 a ) for velocity-dependent damping of a motion of stroke of the damping piston ( 9 ), said velocity-dependent damping device ( 28 a ) comprising

at least one piston member ( 12 , 16 ) which is tightly mounted on the piston rod ( 6 ),

an annular piston ( 23 ) which is displaceable in the direction of the axis ( 5 ) relative to the at least one piston member ( 12 , 16 ), and

at least one elastic valve disk ( 25 , 26 ) which is disposed between the at least one piston member ( 12 , 16 ) and the annular piston ( 23 ) and which bears sealingly against the at least one piston member ( 12 , 16 ) when a given limit of stroke velocity is exceeded; and

another damping device ( 45 ) for path-dependent damping of a motion of stroke of the damping piston ( 9 ),

said path-dependent damping device ( 45 ) comprising a damping fluid passage with a path-dependently varying cross section between the two sectional casing chambers ( 10 , 11 ),

said damping fluid passage being a longitudinal groove ( 45 ) on the inside wall ( 20 ) of the casing ( 1 ),

said longitudinal groove ( 45 ) substantially extending between a position of maximum insertion and a position of maximum extension of the damping piston ( 9 ) and comprising at least

a first groove area ( 48 ) having a varying cross section and being allocated to the position of maximum insertion,

a second groove area ( 49 ) having a constant cross section and adjoining to the first groove area ( 48 ),

a third groove area ( 50 ) having a varying cross section and adjoining to the second groove area ( 49 ), and

a fourth groove area ( 51 ) having a constant cross section and adjoining the third groove area ( 50 ).

2. A gas spring according to claim 1 , wherein the path-dependent damping device ( 45 ) has means for stronger damping of the motion of stroke in an area of two end positions ( 46 ) thereof than in an area ( 51 ) of the remaining stroke.

3. A gas spring according to claim 1 , wherein an embodiment of the path-dependent damping device ( 45 ) has means for multi-stage variation of damping of the motion of stroke.

4. A gas spring according to claim 1 , wherein the cross section of the damping-fluid passage in the area ( 48 , 53 ) of one of the two end positions ( 46 ) of the stroke is smaller than it is in the area ( 51 ) of the remaining stroke.

5. A gas spring according to claim 1 , wherein variation of the cross section of the damping device ( 45 ) takes place in several steps ( 48 , 50 ).

6. A gas spring according to claim 1 , wherein the longitudinal groove ( 45 ) has a varying width for cross-sectional variation.

7. A gas spring according to claim 1 , comprising a damping fluid in the form of temperature-resistant oil.

8. A gas spring according to claim 7 , comprising a synthetic-based damping fluid.

9. A gas spring according to claim 7 , comprising a silicone-based damping fluid.

10. A gas spring according to claim 1 , wherein the longitudinal groove ( 45 ) has a varying depth for cross-sectional variation.

11. A gas spring according to claim 1 , wherein the longitudinal groove ( 45 ) has a varying width and a varying depth for cross-sectional variation.

12. A gas spring, comprising

a cylindrical casing ( 1 ) which has an inside wall ( 20 ), a central longitudinal axis ( 5 ), a bottom ( 2 ) and an end ( 4 ) opposite the bottom ( 2 );

a piston rod ( 6 ) which is concentric of the central longitudinal axis ( 5 ) and which is extended from the end ( 4 ) through a guide and seal unit ( 8 ) and out of the casing ( 1 );