Single side wall air bag inflator and method of making the same

• US 5,683,106 A
• Filed: 02/07/1996
• Issued: 11/04/1997
• Est. Priority Date: 10/05/1994
• Status: Expired due to Fees

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Morton International Incorporated (Autoliv Incorporated)
• Inventors: Fulmer, Brian H.
• Primary Examiner(s): Dickson, Paul N.
• Application Number:
  US08/598,012
• Time in Patent Office: 636 Days
• Field of Search: 280/741, 280/736, 280/742, 102/530, 102/531
• US Class Current: 280/741
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder

Abstract

A new and improved single side wall air bag inflator includes a housing containing an ignition device, a quantity of pyrotechnic gas generant material and a filter. The housing includes a cup-shaped base member having an annular bottom wall with a central opening for access to the ignition device and an integrally formed, upstanding ported side wall extends upwardly of the bottom wall. The side wall has a radially inwardly deformable, free upper end portion forming a retaining flange for securing a top wall in place spaced above the bottom wall and closing off an upper end portion of the housing. The top wall has a depressed outer peripheral edge portion facing and sealed with the downwardly and radially inwardly deformed upper end flange of the single side wall.

Claims

1. A single side wall housing for an air bag inflator of the type having a central ignition source for igniting gas generating material radially outwardly thereof producing gas to flow radially outwardly toward said single side wall, comprising:

a cup-shaped base having an annular bottom wall with a central ignition opening and only one side wall, said one side wall being an integrally formed, ported, outer side wall extending upwardly from the periphery of said bottom wall defining a single internal chamber and having a free upper end portion deformed downwardly and radially inwardly forming an upper end flange for securing a top wall in place for closing the upper end of said housing;

a top wall spaced above said bottom wall having an outer peripheral edge portion facing and sealed with said end flange of said outer side wall, said outer peripheral edge portion being depressed downwardly of a central portion thereof to accomodate said end flange of said outer side wall and provide a smooth upper end face for said housing;

an ignition source comprising a high energy electrically activated ignition train having a body extending upwardly into a central portion of said base and formed with an outer face closing said central opening of said annular bottom wall;

a quantity of pyrotechnic gas generating material in said housing positioned to immediately surround said body of said ignition source around said ignition opening;

an annular unitary filter immediately surrounding said quanity of gas generating material, said unitary filter being positioned adjacent an inside surface of said ported outer side wall and extending between said bottom wall and said depressed outer peripheral edge portion of said top wall, with said unitary filter serving as a sole support for said top wall;

annular seal means disposed on opposite, upper and lower end faces of said unitary filter for sealing against said top wall and said bottom wall, respectively, to prevent blow by of gas from said generating material around said filter means to reach said ported outer side wall; and

,

said housing having no ported, internal side walls supporting said top wall and separating said housing into multiple distinct internal chambers.

2. The housing of claim 1, wherein:

said cup-shaped base is formed of stamped sheet metal.

3. The housing of claim 1, wherein:

said top wall is formed of sheet metal and said downwardly depressed peripheral edge portion of said top wall is formed in a stamping operation.

4. The housing of claim 1, including:

a layer of thin foil bonded to an inside surface of said ported outer side wall for sealing the interior of said housing against entry of outside contaminants.

5. The housing of claim 1, wherein:

said annular seal means on said upper end face of said unitary filter forms a hermetic seal between said outer side wall and said top wall.

6. The housing of claim 1, including:

said annular bottom wall of said cup-shaped base having a deflectable annular flange around said central opening adapted to be deformed against said ignition source for securing the same in place over said central opening.

7. The housing of claim 6, wherein:

said bottom wall includes a rim around said central opening facing a peripheral edge portion of said outer face of said ignition source.

8. An air bag inflator of the type including a single side wall housing containing centralized ignition means, and pyrotechnic gas generating means and filter means extending respectively radially outwardly of and surrounding said ignition means, comprising:

a cup-shaped base having an annular bottom wall with a central opening for access to said ignition means and an integrally formed, single, ported, outer side wall extending upwardly from the periphery of said bottom wall defining a single interior compartment and having a free upper end portion deformed downwardly and radially inwardly forming an upper end flange;

a top wall spaced above said bottom wall closing off said upper end of said outer side wall for protectively containing said gas generating means and said filter means and having an outer peripheral edge portion depressed downwardly of a central portion thereof to entirely accommodate said upper end flange of said outer side wall and seal said top wall to close said upper end;

ignition means comprising a high energy electrically activated ignition train having a body extending upwardly into a central portion of said base and formed with an outer face closing said central opening of said annular bottom wall, said annular bottom wall including an upwardly extending flange around said central opening deformed downwardly and radially inwardly against said body of said ignition train for securing said body in place in said housing and sealingly closing said central opening against the entry of outside contaminants;

a quantity of pyrotechnic gas generating material in said housing positioned immediately surrounding said body of said ignition means around said ignition opening;

an annular unitary filter immediately surrounding said quantity of gas generating material said unitary filter being positioned adjacent an inside surface of said ported outer side wall and extending between said bottom wall and said depressed outer peripheral edge portion of said top wall with said unitary filter solely supporting said top wall along said depressed outer peripheral edge portion;

annular seal means disposed on opposite, upper and lower end faces of said unitary filter for sealing against said top wall and said bottom wall, respectively, said annular seal means being compressed between said unitary filter and said top wall and said bottom wall, respectively, to prevent blow by of gas from said generating material around said filter means to reach said ported outer side wall;

said housing having no ported, interior side walls for supporting said top wall and for separating said housing into multiple distinct interior compartments.

9. The air bag inflator of claim 8, wherein:

said ignition train body has a radially outwardly extending lower end flange adjacent said outer face at a lower end facing a peripheral edge portion of said bottom wall around said central opening and sealed therewith by second annular seal means.

10. The housing of claim 8, wherein:

said cup-shaped base is formed in a forging process.

11. The air bag inflator of claim 8, wherein:

said annular seal means includes a pair of upper and lower resilient sealing rings between said unitary filter ends and said top wall and bottom wall, respectively.

12. The air bag inflator of claim 11, wherein:

an upper one of said resilient sealing rings provides a hermetic seal between said outer side wall and said top wall.

13. The air bag inflator of claim 8, including:

a rupturable seal between said ported outer side wall and said outer surface of said annular unitary filter for preventing entry of outside contaminants into internal components contained in said housing.

14. The air bag inflator of claim 13, wherein:

said rupturable seal comprises a thin band of impervious material secured to an inside surface of said ported outer side wall rupturable when said gas generating means is activated by said ignition means.

15. The air bag inflator of claim 8, including:

mounting flange means secured to said base.

16. The air bag inflator of claim 15, wherein:

said mounting flange means extends radially outwardly of said outer side wall of said base.

17. The air bag inflator of claim 16, wherein:

said mounting flange means is secured to said outer side wall by welding.

18. The air bag inflator of claim 16, wherein:

said mounting flange means is press fitted onto said outer side wall.

19. A method of making a single side wall air bag inflator, comprising the steps of:

forming a cup-shaped base with an annular bottom wall with a central ignition opening and only a single integral, upstanding, ported, outer side wall around the periphery of said bottom wall defining a single interior compartment, without forming one or more ported interior side walls dividing said single interior compartment into a plurality of separate interior compartments;

mounting a high energy ignition device in said central ignition opening said ignition device being sealed and held in place by deforming an upstanding integral flange disposed on said bottom wall around said central ignition opening against a body of said ignition device;

inserting a unitary annular filter in said base immediately adjacent an inside surface of said single outer side wall and outwardly surrounding said ignition device forming an annular space for containing a quantity of gas generating material;

filling said annular space with a quantity of gas generating material immediately surrounding said body of said ignition device and immediately adjacent an inside surface of said unitary annular filter; and

,

covering said ignition device, said quantity of gas generating material and said unitary annular filter with a top wall, said top wall being placed within said base immediately adjacent an inside surface of a free upper end portion of said single outer side wall and being held in place and completely supported on said unitary filter by deforming said free upper end portion of said single outer side wall downwardly and radially inwardly over a downwardly depressed outer peripheral edge portion formed on said top wall until said outer peripheral edge portion is solely supported on said unitary filter to form a closed housing for said air bag inflator.

20. The method of claim 19, including the step of:

mounting a sealing ring between said ignition device and said annular bottom wall.

21. The method of claim 19, including the step of:

mounting a sealing ring between a lower face of said annular filter and said annular bottom wall.

22. The method of claim 21, including the step of:

mounting a sealing ring between said top wall and an upper face of said annular filter.

23. The method of claim 19, including the step of:

mounting a rupturable sealing ring on an inside surface of said single outer side wall to cover the ports therein.

24. The method of claim 19, wherein:

said peripheral outer edge portion is depressed by an amount substantially equal to the thickness of said upper end flange of said single outer side wall.

25. The method of claim 22, wherein:

said sealing rings between said annular filter and said top and bottom walls are compressed when said upper end flange of said single outer side wall is deformed.