Gas generator for an airbag module

• US 8,276,521 B2
• Filed: 03/25/2010
• Issued: 10/02/2012
• Est. Priority Date: 10/05/2007
• Status: Expired due to Fees

• Current Assignee: Takata-Petri AG
• Original Assignee: Takata AG (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Reichelt, Silvio, Zhang, Jiang, Dolzhanskiy, Vladimir, Von Breitenbach, Gerrit, Kratz, Heiko
• Primary Examiner(s): BERGIN, JAMES S
• Application Number:
  US12/659,933
• Publication Number:
  US 20100186616A1
• Time in Patent Office: 922 Days
• Field of Search: 102/530, 102/531, 280/741, 280/736
• US Class Current: 102/530
• 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

The invention relates to a gas generator for an airbag module having a gas generator housing, in which a first chamber for receiving a propellant for igniting a main gas set in a second chamber, and an ignition device for the ignition of the propellant are provided. In order to simplify the production of the gas generator, the invention provides that the first chamber for receiving the propellant is limited by a pipe, on the first end of which the ignition device is disposed, and the second end of which reaches the gas generator housing at least approximately. The first and the second chamber are separated from each other such that no parts of the propellant may reach the second chamber via the second end of the pipe before the ignition of the propellant.

Claims

1. A gas generator for an airbag module, comprising:

a gas generator housing having a first chamber and a second chamber;

a propellant arranged in the first chamber;

a main gas generating material arranged in the second chamber, the propellant in the first chamber configured to ignite the main gas generating material in the second chamber; and

an ignition device for ignition of the propellant,

wherein the first chamber for receiving the propellant is restricted by a pipe, on a first end of which the ignition device is arranged,

wherein a second end of the pipe reaches the gas generator housing such that, before the ignition of the propellant, the second end of the pipe rests directly against the gas generator housing or that, before the ignition of the propellant, between the second end of the pipe and the gas generator housing a gap is present caused by production tolerances so small that no products of the propellant can reach the second chamber via the second end of the pipe, and

wherein the second end of the pipe reaches the gas generator housing such that the gas generator housing is deformable by pressure generated after the ignition of the propellant in the pipe and the pipe is arranged in such a way that an intermediate space is generated between the second end of the pipe and the gas generator housing so that hot gases generated by the ignition of the propellant can flow through the intermediate space between the second end of the pipe and the gas generator housing from the first chamber into the second chamber containing the main gas generating material.

2. The gas generator according to claim 1, wherein the gas generator is cup-shaped such that the pipe extends between the ignition device extending from a bottom of the gas generator to a cover of the gas generator.

3. The gas generator according to claim 1, wherein a pyrotechnical load is provided in the first chamber,

wherein the gas generator housing at least partially encloses the first chamber,

wherein the pipe restricts a section of the first chamber,

wherein a movable part movable relatively to the pipe is provided, which restricts the first chamber towards a portion of the gas generator housing,

wherein means for exerting a restoring force on the movable part is provided in order to keep the movable part in thermal contact with the gas generator housing such that the first chamber is in thermal contact with the gas generator housing via the movable part, and

wherein the means for exerting a restoring force preloads the movable part against the gas generator housing.

4. The gas generator according to claim 3, wherein the movable part at least partially covers an opening formed in the second end of the pipe, and wherein the movable part is formed flange-like such that a first section of the movable part extends along an inner circumference of the pipe and a second section of the movable part at least partially covers the opening.

5. The gas generator according to claim 4, wherein one side of the second section of the movable part rests against an inner surface of the gas generator housing.

6. The gas generator according to claim 4, wherein the second section of the movable part projects with one overhang over the opening.

7. The gas generator according to claim 3, wherein the means for exerting a restoring force comprises an elastic element or a spring-like element.

8. The gas generator according to claim 3, wherein the means for exerting a restoring force has an elastic element which is arranged between the second end of the pipe and an inner surface of the gas generator housing and which is temperature-resistant up to a temperature which is above an ignition temperature of the pyrotechnical load.

9. The gas generator according to claim 8, wherein the elastic element is arranged between the second end of the pipe and an overhang of the movable part.

10. The gas generator according to claim 3, wherein the means for exerting a restoring force has an elastic element, which simultaneously seals the first chamber against the second chamber.

11. The gas generator according to claim 3, wherein the movable part releases, under an impact of a gas pressure in the first chamber generated by igniting the pyrotechnical load, an outflow opening through which the gas can flow out of the first chamber, and wherein the gas can flow out of the first chamber via the outflow opening into the second chamber.

12. The gas generator according to claim 3, wherein the movable part has a pre-determined breaking point, which breaks when the pressure in the first chamber exceeds a certain value so that the movable part releases an outflow opening in an area of the pre-determined breaking point.

13. The gas generator according to claim 1, wherein the second end of the pipe is in close contact to an elastic gas guiding plate, which at least sectionally rests on an inside of the gas generator housing.

14. The gas generator according to claim 13, wherein the gas guiding plate has a cup-shaped section, into which the second end of the pipe projects such that the second end of the pipe rests closely against a side wall of the cup-shaped section without being connected to the side wall of the cup-shaped section via auxiliary means.

15. The gas generator according to claim 14, wherein, in an area of the first end of the pipe, an inner wall of the pipe is pressed fit against a receptacle for the ignition device, and wherein, in an area of the second end of the pipe, an outer wall of the pipe is pressed fit against the side wall of the cup-shaped section.

16. The gas generator according to claim 13, wherein the generator housing and the gas guiding plate are deformable in an area of the second end of the pipe by the pressure generated after ignition of the propellant in the pipe such that:

(i) a space is present between the second end of the pipe and the gas guiding plate and therefore a connection between the first chamber and the second chamber is present;

or

(ii) a space is present between the first end of the pipe and the ignition device and therefore a connection between the first chamber and the second chamber is present.

17. The gas generator according to claim 13, wherein the gas generator housing is deformable on a side of the first end of the pipe or the ignition device by a pressure wave generated after the ignition of the propellant in the pipe such that:

(i) a space between the first end of the pipe and the ignition device and therefore a connection between the first chamber and the second chamber is present, or

(ii) a space between the second end of the pipe and the gas guiding plate and therefore a connection between the first chamber and the second chamber is present.

18. The gas generator according to claim 13, wherein at least one circular bead is provided in a bottom of the gas guiding plate for adjusting stiffness and elastic resilience of the gas guiding plate.

19. A vehicle occupant restraining system, comprising:

an airbag module comprising a gas generator according to claim 1.