Gas generator

• US 6,079,740 A
• Filed: 06/03/1998
• Issued: 06/27/2000
• Est. Priority Date: 06/03/1997
• Status: Expired due to Fees

• Current Assignee: TRW Airbag Systems GmbH & Co., KG
• Original Assignee: TRW Airbag Systems GmbH & Co., KG
• Inventors: Leifheit, Markus, Esau, Anja, Barth, Thomas, Hofmann, Achim, Werneth, Josef
• Primary Examiner(s): English, Peter C.
• Assistant Examiner(s): JASMIN, LYNDA C
• Application Number:
  US09/089,561
• Time in Patent Office: 755 Days
• Field of Search: 280/741, 280/742, 280/736, 280/737, 102/530, 102/531, 422/164
• US Class Current: 280/737
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder
• CPC Class Codes: B60R 21/272 with means for increasing the pressure of the gas just before or during liberation, e.g. hybrid inflators

Abstract

A gas generator, in particular for vehicle occupant restraint systems, with at least one combustion chamber containing propellant, and with at least one igniter arranged close to the propellant, for igniting the propellant is characterized in that the combustion chamber is separated from the igniter by an expansion chamber surrounding the igniter and provided for the gas developing on deflagration of the ignition material.

Claims

1. A hybrid gas generator for vehicle occupant restraint systems, comprising:

a housing having an outer wall;

at least one outflow opening in said outer wall for the outlet of generated gas;

at least one combustion chamber containing propellant, present in tablet form;

at least one igniter arranged close to said propellant for igniting said propellant;

said igniter comprising an ignition material; and

an expansion chamber for said generated gas developing on deflagration of said ignition material, which expansion chamber immediately adjoins said igniter in a circumferential direction and a pressure chamber containing stored compressed gas in the non-activated state of said gas generator;

said expansion chamber separating said combustion chamber from said igniter; and

said combustion chamber with said propellant being open with respect to the expansion chamber and said pressure chamber in said non-activated state of said gas generator.

2. The gas generator according to claim 1, wherein said combustion chamber annularly surrounds said expansion chamber.

3. The gas generator according to claim 1, wherein said expansion chamber and said combustion chamber are separated from each other by a diffuser having at least one compressed gas opening, said gas developing on deflagration of said ignition material reaching said combustion chamber via said compressed gas opening, said compressed gas opening being open even in said non-activated state of said gas generator.

4. The gas generator according to claim 3, wherein said diffuser is constructed as a cap and is put over said igniter.

5. The gas generator according to claim 3, wherein said diffuser is radially and axially spaced from said igniter.

6. The gas generator according to claim 1, wherein said combustion chamber is surrounded by said pressure chamber.

7. A hybrid gas generator for vehicle occupant restraint systems, comprising:

a housing having an outer wall;

at least one outflow opening in said outer wall for an outlet of generated gas;

at least one combustion chamber containing propellant;

at least one igniter arranged close to said propellant for igniting said propellant, said igniter comprising an ignition material;

stored compressed gas within said housing;

an expansion chamber for said generated gas developing on deflagration of said ignition material;

said expansion chamber separating said combustion chamber from said igniter;

said expansion chamber and said combustion chamber being separated from each other by a diffuser having at least one compressed gas opening which is open in the non-activated state of said gas generator;

said gas developing on deflagration of said ignition material reaching said combustion chamber via said compressed gas opening; and

said diffuser having a passage opening directed and being open towards said outflow opening in a non-activated state of said gas generator so that gas generated by activation of the igniter can reach the outflow opening without flowing through the combustion chamber.

8. The gas generator according to claim 7, wherein said diffuser is constructed as a cap and is put over said igniter.

9. The gas generator according to claim 7, wherein said diffuser is radially and axially spaced from said igniter.

10. The gas generator according to claim 7, wherein said igniter has a primary and a secondary charge and also an ignition cap surrounding these charges.

11. A gas generator for vehicle occupant restraint systems, comprising:

a housing having an outer wall;

at least one outflow opening in said outer wall for an outlet of generated gas;

at least one combustion chamber containing propellant;

at least one igniter arranged close to said propellant for igniting said propellant;

said igniter comprising ignition material;

an expansion chamber for said generated gas developing on deflagration of said ignition material;

said expansion chamber separating said combustion chamber from said igniter;

said expansion chamber and said combustion chamber being separated from each other by a diffuser having at least one compressed gas opening;

said gas developing on deflagration of said ignition material reaching said combustion chamber via said compressed gas opening;

said housing having a housing base with a filling opening for said propellant, which opening is closed by a base plate;

said igniter being secured in said base plate in a pressure- and gas-tight manner;

said diffuser having an end on a base side; and

an electrically non-conducting body which extends between said base plate welded to said housing base, and said end of said diffuser on said base side, and which also extends into said combustion chamber, where said non-conducting body fixes said propellant, present in tablet form, in its position.

12. The gas generator according to claim 11, wherein said combustion chamber annularly surrounds said expansion chamber.

13. The gas generator according to claim 11, wherein said igniter has a primary charge and a secondary charge and also an ignition cap surrounding these charges.

14. The gas generator according to claim 11, wherein said gas generator is a hybrid gas generator and said combustion chamber is surrounded by a pressure chamber containing compressed gas.

15. The gas generator according to claim 11, wherein a mixing chamber is provided which is separated from said combustion chamber by an intermediate base.

16. A gas generator for vehicle occupant restraint systems, comprising:

a housing having an outer wall;

at least one outflow opening in said outer wall for an outlet of generated gas;

at least one combustion chamber containing propellant;

at least one igniter arranged close to said propellant for igniting said propellant;

said igniter comprising an ignition material; and

an expansion chamber surrounding said igniter for said generated gas developing on deflagration of said ignition material;

said expansion chamber separating said combustion chamber from said igniter;

said gas generator being a hybrid gas generator and said combustion chamber being surrounded by a pressure chamber containing compressed stored gas;

said gas generator further comprising a mixing chamber which is separated from the combustion chamber by an intermediate base; and

said gas generator having a housing base from which a diffuser extends up to said intermediate base, said expansion chamber being open towards said combustion chamber via compressed gas openings and being open towards said mixing chamber via a separate passage opening, said passage opening being open in the non-activated state of said gas generator.

17. The gas generator according to claim 16, wherein said intermediate base separates said mixing chamber from said expansion chamber.

18. A gas generator for vehicle occupant restraint systems, comprising:

a housing having an outer wall;

at least one outflow opening in said outer wall for an outlet of generated gas;

at least one combustion chamber containing propellant;

at least one igniter arranged close to said propellant for igniting said propellant;

said igniter comprising an ignition material; and

an expansion chamber surrounding said igniter for said generated gas developing on deflagration of said ignition material;

said expansion chamber separating said combustion chamber from said igniter;

said expansion chamber and said combustion chamber being separated from each other by a diffuser defining a separate part with at least one compressed gas opening;

said gas developing on deflagration of said ignition material reaching said combustion chamber via said compressed gas opening;

said gas generator being a hybrid gas generator and said combustion chamber being surrounded by a pressure chamber containing stored compressed gas;

said gas generator further comprising a mixing chamber which is separated from the combustion chamber by an intermediate base; and

said diffuser being fixed in position in radial direction on said intermediate base.

19. A gas generator for vehicle occupant restraint systems, comprising:

a housing having an outer wall;

at least one outflow opening in said outer wall for an outlet of generated gas;

at least one combustion chamber containing propellant;

at least one igniter arranged close to said propellant for igniting said propellant;

said igniter comprising an ignition material; and

an expansion chamber surrounding said igniter for said generated gas developing on deflagration of said ignition material;

said expansion chamber separating said combustion chamber from said igniter, said expansion chamber and said combustion chamber being separated from each other by a diffuser defining a separate part;

said gas generator being a hybrid gas generator and said combustion chamber being surrounded by a pressure chamber containing stored compressed gas;

said gas generator further comprising a mixing chamber which is separated from the combustion chamber by an intermediate base; and

said gas generator having a housing base from which said diffuser extends up to said intermediate base and said diffuser having a central passage opening via which gases and particles developing on deflagration of said ignition material can move towards said outflow opening which is closed by a bursting sheet.

20. The gas generator according to claim 19, wherein a central opening in said diffuser and a passage opening in alignment therewith in said intermediate base are provided and permit a direct impact on said bursting sheet by gases and particles developing on deflagration of said ignition material.