Gas generator for an airbag module

• US 20100186616A1
• Filed: 03/25/2010
• Published: 07/29/2010
• Est. Priority Date: 10/05/2007
• Status: Active Grant

• Current Assignee: Takata-Petri AG
• Original Assignee: Takata-Petri AG
• Inventors: Dolzhanskiy, Vladimir, Von Breitenbach, Gerrit, Reichelt, Silvio, Kratz, Heiko, Zhang, Jiang
• Granted Patent: US 8,276,521 B2
• Time in Patent Office: Days
• 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 with 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, and that the first chamber for receiving the propellant is restricted by a pipe, on the first end of which the ignition device is arranged, wherein the second end of the pipe reaches the gas generator housing such that the second end of the pipe rests against the gas generator housing or a small gap is present between the second end of the pipe and the gas generator housing, such that 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, and that the generator housing is deformable there by the pressure generated after ignition of the propellant in the pipe such that an intermediate space is generated between the second pipe end and the gas generator housing so that the hot gases generated by the ignition of the propellant can flow through the intermediate space between the pipe end and the gas generator housing from the first into the second chamber containing the main gas set.

3. The gas generator according to claim 1, wherein by using a cup-shaped gas generator the pipe extends between the ignition device extending from the bottom of the gas generator into the gas generator and the cover of the gas generator.

4. The gas generator according to claim 1, wherein the first chamber for arranging a pyrotechnical load is provided, wherein the housing encloses the chamber at least partially, wherein the pipe restricts a section of the chamber and wherein a part movable relatively to the pipe is provided, which restricts the chamber towards the housing and wherein means are provided for exerting a restoring force on the part in order to keep it in thermal contact with the housing such that the chamber is in thermal contact with the surrounding of the housing via the movable part and the housing, wherein the means for exerting a restoring force preload the movable part against the housing.

5. The gas generator according to claim 4;

wherein the movable part covers at least partially an opening formed in the end of the pipe, wherein the movable part is formed flange-like, whereby the first section extends along an inner circumference of the pipe and a second section covers the opening at least partially.

6. The gas generator according to claim 5;

wherein the second section rests against an inner surface of the housing with one side.

7. The gas generator according to claim 5, wherein the second section projects with one overhang over the opening.

8. The gas generator according to claim 4, wherein the means for exerting a restoring force comprises an elastic element or a spring-like element.

9. The gas generator according to claim 8, wherein the means have an elastic element which is arranged between the end of the first part and the inner surface of the housing and which is temperature-resistant up to a temperature which is above the ignition temperature of the pyrotechnical load.

10. The gas generator according to claim 9, wherein the elastic element is arranged between the end of the first part and the overhang of the second section of the movable part.

11. The gas generator according to claim 4, wherein the means for exerting a restoring force has an elastic element, which simultaneously seals the first chamber against the second chamber.

12. The gas generator according to claim 4, wherein the movable part releases under the impact of a gas pressure in the chamber generated by igniting the pyrotechnical load an outflow opening through which the gas can flow out of the chamber, wherein the gas can flow out of the first chamber via the outflow opening into the second chamber.

13. The gas generator according to claim 4;

wherein the movable part has a pre-determined breaking point, which breaks when the gas pressure in the chamber exceeds a certain value so that the movable part releases in the area of the predetermined breaking point an outflow opening.

14. The gas generator according to claim 1, wherein the first chamber for receiving the propellant is restricted by the pipe, on the first end of which the ignition device is arranged and the second end of which is in close contact to an elastic gas guiding plate, which at least sectionally rests on the inside against the gas generator housing.

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

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

17. Gas generator according to claim 14, wherein the generator housing and the gas guiding plate are deformable in the area of the second end of the pipe by the pressure generated after ignition of the propellant in the pipe such that a space is present between the second end of the pipe and the gas guiding plate and therefore a connection between the first and the second chamber is present or a space between the first end of the pipe and the ignition device and therefore a connection between the first and the second chamber is present.

18. The Gas generator according to claim 14, wherein the gas generator housing is deformable on the side of the first end of the pipe or the ignition device by the pressure wave generated after ignition of the propellant in the pipe such that a space between the first end of the pipe and the ignition device and therefore a connection between the first and the second chamber is present, or a space between the second end of the pipe and a gas guiding plate and therefore a connection between the first and the second chamber is present.

19. The gas generator according to claim 14, wherein for adjusting the stiffness and elastic resilience of the gas guiding plate at least one circular bead is provided in its bottom.

20. A vehicle occupant restraining system with an airbag module having a gas generator according to claim 1.

2. A gas generator for an airbag module with 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, and that the first chamber for receiving the propellant is restricted by a pipe, on the first end of which the ignition device is arranged, wherein between the gas generator housing and the second end of the pipe an intermediate space is provided, which is blocked by a film, which is torn open by the pressure in the first chamber after ignition of the propellant.