Gas Generator

• US 6,474,685 B1
• Filed: 04/06/2000
• Issued: 11/05/2002
• Est. Priority Date: 04/06/1999
• Status: Expired due to Term

• Current Assignee: TRW Airbag Systems GmbH & Co., KG
• Original Assignee: TRW Airbag Systems GmbH & Co., KG
• Inventors: Müller, Werner, Meixner, Rudolf, Ragner, Herbert
• Primary Examiner(s): Johnson, Brian L.
• Assistant Examiner(s): PHAN, HAU VAN
• Application Number:
  US09/544,408
• Time in Patent Office: 943 Days
• Field of Search: 280/736, 280/741, 280/742, 280/737, 280/738, 280/740, 222/5
• US Class Current: 280/741
• CPC Class Codes: B60R 2021/2633 with a plurality of inflation levels
• CPC Class Codes: B60R 2021/2648 comprising a plurality of combustion chambers or sub-chambers
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder

Abstract

A gas generator for a vehicle occupant restraint system. The gas generator comprises a housing, a filter chamber, and a combustion chamber which is filled with solid propellant and which has an outflow end. The gas generator further comprises at least one igniter unit which has an igniter and ignites the solid propellant, and comprises at least one filter which adjoins the solid propellant at the outflow end and delimits the combustion chamber. The filter has a central part which at least in sections has the shape of a cone and tapers in a direction towards an interior of the combustion chamber. The solid propellant laterally adjoins the conical section.

Claims

1. A gas generator, for a vehicle occupant restraint system, said gas generator comprising:

a housing,

a filter chamber,

a combustion chamber filled with solid propellant and having an outflow end,

at least one igniter unit having an igniter, and igniting said solid propellant, said solid propellant, when ignited, generating gas and filterable particles, and

at least one gas permeable filter for trapping said filterable particles while allowing flow through of said generated gas, said at least one filter adjoining said solid propellant at said outflow end and delimiting said combustion chamber,

said filter having a gas permeable central part in the shape of a truncated cone tapering in a direction towards an interior of said combustion chamber, said solid propellant laterally adjoining said central part, and said filter having a hollow and tubular cylindrical section which adjoins said central part in said direction towards said interior of said combustion chamber.

2. The gas generator according to claim 1, wherein the whole of said central part of said filter has said shape of a cone.

3. The gas generator according to claim 1, wherein said filter comprises wall sections and an end of said cylindrical section projecting in said direction towards said interior of said combustion chamber is closed by compressing said wall sections.

4. The gas generator according to claim 1, wherein said filter consists of a plurality of layers.

5. The gas generator according to claim 1, wherein said gas generator is constructed in a tubular shape having an elongated cylindrical housing, in which said combustion chamber and said filter chamber are arranged axially one behind the other, and wherein said conical section of said filter is arranged coaxially in said housing.

6. The gas generator according to claim 1, wherein a filter chamber is located downstream of said combustion chamber, said filter chamber having a wall with flow-through openings, said at least one filter being located upstream of said wall of said filter chamber, said at least one filter spacing said combustion chamber from said filter chamber.

7. The gas generator according to claim 6, wherein said filter closes off said combustion chamber towards said filter chamber and an expansion chamber is formed between said filter and said wall of said filter chamber.

8. A gas generator, for a vehicle occupant restraint system, said gas generator comprising:

a housing,

a filter chamber,

a combustion chamber filled with solid propellant and having an outflow end,

at least one igniter unit having an igniter, and igniting said solid propellant, said solid propellant, when ignited, generating gas and filterable particles, and

at least one gas permeable filter for trapping said filterable particles while allowing flow through of said generated gas, said at least one filter adjoining said solid propellant at said outflow end and delimiting said combustion chamber,

said filter having a gas permeable central part having at least in sections the shape of a cone tapering in a direction towards an interior of said combustion chamber, said solid propellant laterally adjoining said central part,

at least one intermediate wall which is gas permeable over its entire extension being arranged in said combustion chamber, said intermediate wall dividing said combustion chamber into at least two partial chambers which are filled with propellant and open towards said igniter unit, and said partial chambers each comprising an open end so that said propellant contained in said two partial chambers is ignited via said open ends.

9. The gas generator according to claim 8, wherein said combustion chamber has a connecting section filled with propellant, said connecting section lying between said igniter unit and said partial chambers and continuing into said partial chambers.

10. The gas generator according to claim 9, wherein said intermediate wall ends in front of said connecting section.

11. The gas generator according to claim 8, wherein said filter chamber is arranged downstream of said combustion chamber, a wall being provided which has through-flow openings and separates said combustion chamber and said filter chamber from each other, wherein by an arrangement of said igniter and said through-flow openings and also a geometry of said combustion chamber a main flow direction is defined for generated hot gas, and wherein said intermediate wall extends substantially parallel to said main flow direction.

12. The gas generator according to claim 8, wherein said filter and said intermediate wall are fastened to each other.

13. The gas generator according to claim 8, wherein said gas generator is a tubular gas generator with an elongated cylindrical housing, said igniter unit being arranged at an axial end of said housing and said intermediate wall being arranged coaxially to said housing, and said combustion chamber and said filter chamber are arranged axially one behind the other.