Double swage airbag inflator vessel and methods for manufacture thereof

Patent metadata

Field	Value
Publication number	US-9776592-B2
Application number	US-201313973653-A
Country	US
Kind code	B2
Filing date	Aug 22, 2013
Priority date	Aug 22, 2013
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

A high strength dual-swaged airbag inflator vessel comprising a high strength metal material, such as low carbon steel, has a swaged terminal end defining two distinct swaged portions. A reduction of diameter within one of the swaged portions is restricted to be less than or equal to about 30% and in certain variations, less than or equal to about 16% to minimize cold work strain hardening and to reduce loss of ductility. In certain aspects, a second swaged portion within the swaged terminal end has a length of less than or equal to about 10 mm. Methods for making such a dual-swaged airbag inflator vessel are likewise provided. Such dual swage designs have improved reliability and performance in high pressure inflator applications, as well as reduced manufacturing costs.

First claim

What is claimed is:

1. A method of forming a dual-swaged airbag inflator vessel from a hollow cylindrical metal workpiece having a first outer diameter, the method comprising:
swaging a first portion of a terminal end of the workpiece at a cold working temperature to reduce the first outer diameter of the first portion by a first amount to a second outer diameter, the second outer diameter being less than the first outer diameter; and
swaging a second portion of the terminal end for a second time at the cold working temperature to reduce the second portion by a second amount from the second outer diameter to a third outer diameter, the first portion of the terminal end including the second portion of the terminal end, the first portion having a first length and the second portion having a second length that is less than the first length, the first and second portions extending to a distalmost end of the workpiece, the third outer diameter being less than the second outer diameter, wherein a sum of the first amount and the second amount is less than 26 percent.

2. The method of claim 1 , wherein the first amount is less than or equal to 16 percent.

3. The method of claim 1 , wherein the second length is less than or equal to 10 mm.

4. The method of claim 1 , further comprising:
inserting the terminal end of the workpiece into an opening in a dual swage die, the dual swage die; and
applying an axial force to move the terminal end further into the dual swage die and force the terminal end into engagement with an internally contoured surface of the dual swage die, the internally contoured surface including a first cylindrical surface having a first inner diameter, a second cylindrical surface having a second inner diameter that is less than the first inner diameter, and a third cylindrical surface having a third inner diameter that is less than the second inner diameter.

5. The method of claim 4 wherein:
the internally contoured surface also has a first tapering cylindrical surface and a second tapering cylindrical surface, the first tapering cylindrical surface extending axially between the first and second cylindrical surfaces, the second tapering cylindrical surface extending axially between the second and third cylindrical surfaces;
swaging the first portion of the terminal end to reduce the first portion by the first amount includes forcing the first portion into engagement with the first tapering cylindrical surface; and
swaging the second portion of the terminal end for the second time to reduce the second portion by the second amount includes forcing the second portion into engagement with the second tapering cylindrical surface.

6. A method of forming a dual-swaged airbag inflator vessel from a hollow cylindrical metal workpiece having a first outer diameter, the method comprising:
swaging a first portion of a terminal end of the workpiece at a cold working temperature to reduce the first outer diameter of the first portion by a first amount to a second outer diameter, the second outer diameter being less than the first outer diameter; and
swaging a second portion of the terminal end for a second time at the cold working temperature to reduce the second portion by a second amount from the second outer diameter to a third outer diameter, the first portion of the terminal end including the second portion of the terminal end, the first portion having a first length and the second portion having a second length that is less than the first length, the first and second portions extending to a distalmost end of the workpiece, the third outer diameter being less than the second outer diameter, wherein the first and second amounts are each less than or equal to 16 percent.

7. An airbag inflator vessel comprising:
a tubular body having a terminal end, the terminal end including:
(i) a first cylindrical portion having a first outer diameter;
(ii) a second cylindrical portion located distally relative to the first cylindrical portion and having a second outer diameter that is less than the first outer diameter by a first amount; and
(iii) a third cylindrical portion located distally relative to the second cylindrical portion and having a third outer diameter that is less than the second outer diameter by a second amount, wherein a sum of the first and second amounts is less than 26 percent.

8. The airbag inflator vessel of claim 7 , wherein the first amount is less than or equal to 16 percent.

9. The airbag inflator vessel of claim 7 , wherein the first and second amounts are each less than or equal to 16 percent.

10. The airbag inflator vessel of claim 7 , wherein the third cylindrical portion has a length that is less than or equal to 10 mm.

11. The airbag inflator vessel of claim 7 , wherein the third cylindrical portion has a length that is less than or equal to 4 mm.

12. The airbag inflator vessel of claim 7 , wherein the terminal end further includes:
a first hollow conical frustum portion disposed axially between the first cylindrical portion and the second cylindrical portion; and
a second hollow conical frustum portion disposed axially between the second cylindrical portion and the third cylindrical portion.

13. The airbag inflator vessel of claim 12 , wherein the first hollow conical frustum portion extends from the first cylindrical portion to the second cylindrical portion.

14. An airbag inflator vessel comprising:
a hollow cylindrical body have a first end, a second end, and an inner surface that defines a storage chamber extending between the first and second ends, the body including an untapered region disposed between the first and second ends and a tapered region disposed at the second end, the untapered region having a first outer diameter, the tapered region including:
(i) a first cylindrical portion located adjacent to the untapered region and having a second outer diameter that is less than the first outer diameter by a first amount; and
(ii) a second cylindrical portion disposed axially between the first cylindrical portion and the second end of the hollow cylindrical body, the second cylindrical portion having a third outer diameter that is less than the second outer diameter by a second amount, wherein each of the first and second amounts is less than or equal to 16 percent.

15. The airbag inflator vessel of claim 14 , wherein a sum of the first amount and the second amount is less than 26 percent.

16. The airbag inflator vessel of claim 14 , wherein the second cylindrical portion has a length that is less than or equal to 10 mm.

17. The airbag inflator vessel of claim 14 , wherein the second cylindrical portion has a length that is less than or equal to 4 mm.

18. The airbag inflator vessel of claim 14 , wherein the tapered region further includes:
a first hollow conical frustum portion disposed axially between the untapered region and the first cylindrical portion of the tapered region; and
a second hollow conical frustum portion disposed axially between the first cylindrical portion and the second cylindrical portion.

19. The airbag inflator vessel of claim 14 , wherein the tapered region is free of any diameter enlargements in a direction extending axially from the untapered region of the hollow cylindrical body to the second end of the hollow cylindrical body.

Assignees

• Autoliv Asp Inc

Inventors

• Lang Shawn
• Clark Ken

Classifications

• C22C38/40

  with nickel · CPC title

• C22C38/06

  containing aluminium · CPC title

• B60R2021/26082

  Material · CPC title

• C22C38/002

  containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60 · CPC title

• B60R21/217 Primary

  Inflation fluid source retainers, e.g. reaction canisters; Connection of bags, covers, diffusers or inflation fluid sources therewith or together · CPC title