Airbag inflator with components protected from high-temperature, reactive generated gases

• US 5,779,267 A
• Filed: 10/15/1996
• Issued: 07/14/1998
• Est. Priority Date: 03/27/1995
• Status: Expired due to Fees

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Inventors: Jordan, Michael P., Rink, Linda M., Hock, Christopher, Ward, Alan J.
• Primary Examiner(s): English, Peter C.
• Application Number:
  US08/716,931
• Time in Patent Office: 637 Days
• Field of Search: 280/741, 280/740, 280/736, 280/742, 55/435, 55/524, 102/530, 102/531, 422/164, 422/165, 422/166, 422/167
• US Class Current: 280/740
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder
• CPC Class Codes: C06D 5/06 by reaction of two or more solids

Abstract

Components of a vehicle airbag gas generator, or inflator, are coated with reactivity resistant materials to protect them from deterioration caused by contact with the high temperature, reactive gases generated by recently developed non-azide high reactive temperature gas generating materials. Suitable coatings include those produced from ceramics and reactivity resistant metals. These coatings also provide long term protection of the components from deterioration caused by the environment/atmosphere within the inflator.

Claims

1. In a gas generator for a vehicle airbag assembly comprising:

(a) a housing enclosing a combustion chamber, said housing having an outer wall containing at least one port from which generated gas can be discharged,

(b) said combustion chamber containing a high reaction temperature gas generating material capable of producing sufficient generated gas to inflate an airbag, said gas generating material containing at least one material selected from the group consisting of triazole compounds, tetrazole compounds, salts of 5-nitrobarbituric acid, salts of 5-nitroorotic acid, salts of dicyanamide, nitrate salts of amines and nitrate salts of substituted amines,

(c) a porous structure located in said housing so that the gas generated in the combustion chamber will impinge upon at least a portion of the surface of said porous structure as it flows through the porous structure prior to flowing through said at least one port in said outer wall of said housing;

the improvement comprising providing a coating of a protective material selected from the group consisting of metals and ceramics on said portion of the surface of said porous structure, said coating having a thickness sufficient to protect said porous structure from chemical and ablative deterioration caused by the impingement of said generated gas on said structure.

2. The gas generator of claim 1, wherein said porous structure comprises a porous metal structure.

3. The gas generator of claim 1 wherein said porous structure comprises a structure fabricated from woven or knitted metal wire.

4. The gas generator of claim 3 wherein said metal wire is steel and wherein said coating is copper.

5. The gas generator of claim 3 wherein said coating is applied to said metal wire prior to fabricating said wire into a woven or knitted structure.

6. In a gas generator for a vehicle airbag system, comprising:

a housing enclosing a combustion chamber, said housing having an outer wall containing at least one port from which generated gas can be discharged,

said combustion chamber containing a high reaction temperature gas generating material capable of producing sufficient generated gas to inflate an airbag, said gas generating material containing at least one material selected from the group consisting of triazole compounds, tetrazole compounds, salts of 5-nitrobarbituric acid, salts of 5-nitroorotic acid, salts of dicyanamide, nitrate salts of amines and nitrate salts of substituted amines,

said housing also enclosing a structure located at a position in said housing where at least a portion of said structure will be impinged upon by the gas generated in the combustion chamber as said gas is directed to said at least one port;

the improvement comprising providing a protective coating of a material selected from the group consisting of metals and ceramics on said portion of said structure, said protective coating having a thickness sufficient to protect said structure from chemical and ablative deterioration caused by the impingement of said generated gas on said structure.

7. The gas generator of claim 6 wherein said structure is fabricated from metal.

8. The gas generator of claim 7 wherein said structure is fabricated from a stainless steel.

9. The gas generator of claim 7 wherein said structure is fabricated from a carbon steel.

10. The gas generator of claim 6 wherein said protective coating consists essentially of copper.

11. The gas generator of claim 6 wherein said protective coating consists essentially of zinc.

12. The gas generator of claim 6 wherein said protective coating comprises a ceramic material.

13. The gas generator of claim 12 wherein said ceramic material contains at least one material selected from the group consisting of boron nitride, aluminum silicate, calcium silicate, alumina, silica and zirconia.

14. The gas generator of claim 6 wherein said protective coating has a thickness in the range of 0.0013 to 0.020 inches.

15. In a gas generator for a vehicle airbag system, comprising:

(a) a housing enclosing a combustion chamber and a deflection structure, said housing having an outer wall containing at least one port from which generated gas can be discharged,

(b) said combustion chamber containing a high reaction temperature gas generating material capable of producing sufficient generated gas to inflate an airbag and containing at least one material selected from the group consisting of triazole compounds, tetrazole compounds, salts of 5-nitrobarbituric acid, salts of 5-nitroorotic acid, salts of dicyanamide, nitrate salts of amines and nitrate salts of substituted amines,

(c) said deflection structure being located at a position in said housing where at least a portion of said deflection structure will be impinged on by said generated gas causing the direction of flow of said generated gas to be diverted as said gas flows from its place of generation in said combustion chamber to said at least one port;

the improvement comprising providing a protective coating of a material selected from the group consisting of metals and ceramics on at least said portion of said deflection structure impinged on by said generated gas, said protective coating having a thickness sufficient to protect said portion of said deflection structure from chemical and ablative deterioration caused by the impingement of said generated gas on said structure.

16. The gas generator of claim 15 wherein said material of said protective coating comprises a material selected from the group consisting of boron nitride, aluminum silicate, calcium silicate, alumina, silica, zirconia, zinc, copper, and nickel.

17. The gas generator of claim 15 wherein said portion of said defection structure is shaped as a hollow cylinder and said protective coating covers at least a part of the inner surface of said hollow cylinder.

18. The gas generator of claim 17 wherein said deflection structure includes an inwardly extending flange at one end of said hollow cylinder.

19. The gas generator of claim 15 wherein said protective coating has a thickness in the range of 0.0013 to 0.020 inches.

20. The gas generator of claim 15 wherein said protective coating comprises a ceramic material.

21. The gas generator of claim 15 wherein said deflection structure is formed from steel and said protective coating comprises a ceramic material.

22. A deflection ring for use in the gas generator of a vehicle airbag system, at least a portion of said ring shaped as a hollow cylinder having an interior surface and an exterior surface, said hollow cylinder being fabricated of steel and having a protective coating on at least a part of its surface, said protective coating comprising a ceramic material having a thickness which is sufficient to protect the underlying steel portion of said cylinder from chemical and ablative deterioration when subjected to the impingement of gases generated from high reaction temperature gas generating materials during the activation of said gas generator.

23. The deflection ring of claim 22 further comprising an inwardly extending flange at one end of said portion shaped as a hollow cylinder.

24. The deflection ring of claim 22 wherein said protective coating has a thickness in the range of 0.0013 to 0.020 inches.

25. The deflection ring of claim 22 wherein the ceramic material of said protective coating comprises a material selected from the group consisting of boron nitride, aluminum silicate, calcium silicate, alumina, silica and zirconia.

26. The deflection ring of claim 22 wherein said protective coating is provided on at least a part of the interior surface of said hollow cylinder.