Gas generator

• US 8,047,567 B2
• Filed: 08/07/2008
• Issued: 11/01/2011
• Est. Priority Date: 08/08/2007
• Status: Active Grant

• Current Assignee: TRW Airbag Systems GmbH (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Airbag Systems GmbH (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Zengerle, Werner, Schwuchow, Karsten, Leitl, Josef, Schreiber, Simon, Klimas, Juergen
• Primary Examiner(s): Culbreth; Eric
• Assistant Examiner(s): Spisich; George D.
• Application Number:
  US12/221,810
• Publication Number:
  US 20090039628A1
• Time in Patent Office: 1,181 Days
• Field of Search: 280/736, 280/741, 280/742, 102/530, 102/531, 222/3
• US Class Current: 280/736
• CPC Class Codes: B60R 21/2646 the reacting substances being supported by the inflatable member walls, or by a flexible support within it
• CPC Class Codes: F42B 3/04 for producing gas under pressure generators of inflation fluid especially adapted for vehicle air bags B60R21/26

Abstract

A gas generator, particularly for a vehicle occupant restraint system, has at least one igniter (12), a pyrotechnic solid propellant bed (22), a combustion chamber (20) containing the propellant bed (22) and at least one wall part (24), the wall part (24) being arranged in the combustion chamber (20), which is moved by a gas stream generated on activation of the gas generator into the region of the propellant bed (22) which is not yet ignited, and in its interior (25) defines a gas-directing channel reaching into the propellant bed (22).

Claims

1. A gas generator for a vehicle occupant restraint system, with at least one igniter (12),

a pyrotechnic solid propellant bed (22),

a combustion chamber (20) containing said propellant bed (22) and

at least one wall part (24),

said at least one wall part (24) being constructed so as to be elastic and defining a gas-directing channel in its interior (25), said channel reaching into said propellant bed (22), whereas said at least one wall part (24) extends into a first area of said propellant bed (22) in a non-activated condition, said first area of said propellant bed (22) being situated close to said igniter (12);

and

wherein the at least one wall part (24) is constructed so as to expand into a second area of said propellant bed (22) on activation of said gas generator, said second area of said propellant bed (22) being situated at the end of said combustion chamber (20) that is placed remotely from said igniter (12).

2. The gas generator according to claim 1 wherein said at least one wall part (24) is hollow, has an interior (25) and an exterior (27) and is at least partially open radially during a movement, in order to allow hot gas to flow between the interior (25) of the at least one wall part (24) and the exterior (27) of the at least one wall part (24).

3. The gas generator according to claim 1 wherein an additional wall part is constructed so that it moves as a whole in said combustion chamber (20).

4. The gas generator according to claim 1 wherein said at least one wall part (24) is a spring.

5. The gas generator according to claim 1 wherein said at least one wall part (24) has an open inflow end (31).

6. The gas generator according to claim 5 wherein said at least one wall part (24) has an open or closed outflow end (33) opposed to said inflow end (31), by which said at least one wall part (24) is moved ahead further into said solid propellant bed (22).

7. The gas generator according to claim 1 wherein said at least one wall part (24) divides the combustion chamber (20) on movement into a radially inner and a radially outer section.

8. The gas generator according to claim 1 wherein there is a main direction of flow in said combustion chamber (20) and said at least one wall part (24) is moved in this direction.

9. The gas generator according to claim 1 wherein a mounting is provided for an additional wall part.

10. The gas generator according to claim 9 wherein said mounting is a linear guide.

11. The gas generator according to claim 9 wherein said mounting is a fastening of said additional wall part on one side.

12. The gas generator according to claim 1 wherein an additional wall part is a cylindrical hollow body, with generated gas flowing into an inflow end.

13. The gas generator according to claim 1 wherein in the non-activated state of said gas generator, propellant of said propellant bed (22) is situated inside an additional wall part.

14. The gas generator according to claim 1 wherein a dividing wall (18) is provided and, in the non-activated state of said gas generator, said at least one wall part (24) being adjacent to said dividing wall (18).

15. The gas generator according to claim 14 wherein said dividing wall (18) has at least one through-flow opening (38) which opens into said interior (25) of said at least one wall part (24).

16. The gas generator according to claim 1 wherein said igniter (12) is adjacent to said dividing wall (18) and said dividing wall (18) is adjacent to said hollow interior (25) of said at least one wall part (24).

17. The gas generator according to claim 1 wherein said at least one wall part (24) is a helical spring.

18. A gas generator, for a vehicle occupant restraint system, with at least one igniter (12),

a pyrotechnic solid propellant bed (22),

a combustion chamber (20) containing said propellant bed (22) and

at least one wall part (24),

said at least one wall part (24) being constructed so as to be elastic and arranged in said combustion chamber (20), which is moved by a gas stream generated on activation of said gas generator into a region of said propellant bed (22) which is not yet ignited, and which defines a gas-directing channel in its interior (25), said channel reaching into said propellant bed (22),

wherein the elastic at least one wall part (24) is constructed so as to having an initial length, in a non-activated state of the gas generator, of a maximum of 80% of the length of the propellant bed (22) and the length of said elastic at least one wall part (24) extends, in an activated state of the gas generator, beyond said initial length to a maximum length up to a gas-permeable wall (44) which constitutes an end wall of said combustion chamber (20) more remote of said igniter (12).