Pyrotechnic inflator with central diffuser and composite overwrap

• US 8,979,121 B2
• Filed: 10/30/2012
• Issued: 03/17/2015
• Est. Priority Date: 03/18/2011
• Status: Active Grant

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Inventors: Smith, Bradley W., Cox, Matthew A.
• Primary Examiner(s): ENGLISH, JAMES A
• Application Number:
  US13/664,023
• Publication Number:
  US 20140144343A1
• Time in Patent Office: 868 Days
• Field of Search: 280/741, 280/736, 102530-531
• US Class Current: 280/736
• CPC Class Codes: B60R 2021/26076 characterised by casing
• CPC Class Codes: B60R 2021/26082 Material
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder
• CPC Class Codes: F42B 3/04 for producing gas under pressure generators of inflation fluid especially adapted for vehicle air bags B60R21/26
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

A pyrotechnic inflator assembly including a shell member and an end cap joinable with the shell member to form a subassembly. The subassembly contains a quantity of pyrotechnic material and at least in part defines a combustion chamber wherein at least a portion of the quantity of pyrotechnic material is reactable to form product gas for inflation of an associated airbag cushion and to generate pressure therewithin. A diffuser assembly can be disposed adjacent an end of the shell member and includes flow control features for controlling flow of product gas from the inflator assembly. The inflator assembly further includes a composite overwrap about at least a portion of the subassembly and the diffuser assembly such that the pyrotechnic inflator assembly can withstand the pressure generated within the combustion chamber upon reaction of the pyrotechnic material. Corresponding methods of making a pyrotechnic inflator assembly are also provided.

Claims

1. A pyrotechnic inflator assembly comprising:

a shell member having an inner surface, an outer surface, an open first end and a second end opposite the first end;

an end cap joinable with the shell member to at least in part enclose the open first end of the shell member to form an inflator subassembly, the inflator subassembly containing a quantity of pyrotechnic material and at least in part defining a combustion chamber wherein at least a portion of the quantity of pyrotechnic material is reactable to form product gas for inflation of an associated airbag cushion and to generate pressure within the combustion chamber, the end cap at least in part containing an initiator that upon actuation initiates reaction of the pyrotechnic material;

a diffuser assembly disposed adjacent the second end of the shell member, the diffuser assembly including a plurality of flow control features for controlling flow of product gas from the inflator assembly, the diffuser assembly including a base having a top surface flush with the outer surface of the shell member; and

an overwrap about at least a portion of the inflator subassembly and the base of the diffuser assembly to form the pyrotechnic inflator assembly that withstands the pressure generated within the combustion chamber upon reaction of the pyrotechnic material, the overwrap comprising a composite of fibers and a resin matrix system.

2. The pyrotechnic inflator assembly of claim 1 wherein the shell member is incapable of withstanding the pressure generated within the combustion chamber upon reaction of the pyrotechnic material without support provided by the overwrap.

3. The pyrotechnic inflator assembly of claim 1 wherein the shell member second end is closed.

4. The pyrotechnic inflator assembly of claim 3 wherein the shell member closed second end comprises breakout pressure-controlling scoring.

5. The pyrotechnic inflator assembly of claim 3 wherein the shell member closed second end comprises a seal disposed onto a shell member opening at the second end.

6. The pyrotechnic inflator assembly of claim 1 wherein the diffuser assembly comprises:

a central gas diffuser element and a controlling orifice element at least in part disposed between the central gas diffuser element and the second end of the shell member, the diffuser element comprising a plurality of product gas discharge openings.

7. The pyrotechnic inflator assembly of claim 1 wherein the shell member is formed of metal.

8. The pyrotechnic inflator assembly of claim 7 wherein the shell member metal comprises steel.

9. The pyrotechnic inflator assembly of claim 7 wherein the shell member metal comprises aluminum.

10. The pyrotechnic inflator assembly of claim 1 additionally comprising:

a filter assembly disposed adjacent the inner surface of the second end of the shell member.

11. The pyrotechnic inflator assembly of claim 10 wherein the filter assembly comprises a filter element in operational gas flow alignment with the diffuser assembly.

12. The pyrotechnic inflator assembly of claim 10 additionally comprising:

an igniter assembly at least in part disposed within the filter assembly, the igniter assembly at least in part in operational communication with the initiator assembly.

13. The pyrotechnic inflator assembly of claim 1 additionally comprising:

a damper pad element at least in part disposed between the pyrotechnic material and the end cap.

14. The pyrotechnic inflator assembly of claim 13 wherein the pyrotechnic material is in tablet form.

21. The pyrotechnic inflator assembly of claim 1 wherein the end cap additionally includes mounting provisions to engage an associated airbag module.

22. The pyrotechnic inflator assembly of claim 21 wherein the mounting provisions comprise an extending tab.

15. A pyrotechnic inflator assembly comprising:

a metal shell member having an inner surface, an outer surface, an open first end and a closed second end opposite the first end, the shell member being formed of metal;

an end cap joinable with the shell member to at least in part enclose the open first end of the shell member to form an inflator subassembly, the inflator subassembly containing a quantity of pyrotechnic material and at least in part defining a combustion chamber wherein at least a portion of the quantity of pyrotechnic material is reactable to form product gas for inflation of an associated airbag cushion and to generate pressure within the combustion chamber, the inflator subassembly also including a damper pad element at least in part disposed between the pyrotechnic material and the end cap, the end cap at least in part containing an initiator that upon actuation initiates reaction of the pyrotechnic material;

a diffuser assembly disposed adjacent the second end of the shell member in an outwardly extending direction, the diffuser assembly including a plurality of flow control features for controlling flow of product gas from the inflator assembly, the diffuser assembly including a base having a top surface flush with the outer surface of the shell member;

a filter assembly disposed adjacent the inner surface of the second end of the shell member, the filter assembly comprising a filter element in operational gas flow alignment with the diffuser assembly;

an igniter assembly at least in part disposed within the filter assembly, the igniter assembly at least in part in operational communication with the initiator; and

an overwrap about at least a portion of the inflator subassembly and the base of the adjacently disposed diffuser assembly to form the pyrotechnic inflator assembly that withstands the pressure generated within the combustion chamber upon reaction of the pyrotechnic material, the overwrap comprising a composite of fibers and a resin matrix system,

wherein the shell member is incapable of withstanding the pressure generated within the combustion chamber upon reaction of the pyrotechnic material without support provided by the overwrap.

16. The pyrotechnic inflator assembly of claim 15 wherein the shell member closed second end comprises breakout pressure-controlling scoring.

17. The pyrotechnic inflator assembly of claim 15 wherein the diffuser assembly comprises:

a central gas diffuser element and a controlling orifice element at least in part disposed between the central gas diffuser element and the second end of the shell member, the diffuser element comprising a plurality of product gas discharge openings.

18. The pyrotechnic inflator assembly of claim 15 additionally comprising:

a damper pad element at least in part disposed between the pyrotechnic material and the end cap.

19. The pyrotechnic inflator assembly of claim 15 wherein the pyrotechnic material is in tablet form.

23. The pyrotechnic inflator assembly of claim 15 wherein the end cap additionally includes mounting provisions to engage an associated airbag module.

24. The pyrotechnic inflator assembly of claim 23 wherein the mounting provisions comprise an extending tab.

20. A method of making a pyrotechnic inflator assembly, the method comprising:

joining a shell member having an inner surface, an outer surface, an open first end and a second end opposite the first end, with an end cap to at least in part enclose the open first end of the shell member to form an inflator subassembly, the inflator subassembly containing a quantity of pyrotechnic material and at least in part defining a combustion chamber wherein the at least a portion of the quantity of pyrotechnic material is reactable to form product gas for inflation of an associated airbag cushion and to generate pressure within the combustion chamber;

positioning a diffuser assembly adjacent the second end of the shell member of the inflator subassembly in an outwardly extending direction to form an inflator device precursor, the diffuser assembly including a base having a top surface flush with the outer surface of the shell member;

overwrapping at least a portion of the inflator subassembly and the base of the adjacently disposed diffuser assembly with a composite of fibers and a resin matrix system to form a composite overwrapped inflator device precursor; and

treating the composite overwrapped inflator device precursor to form the pyrotechnic inflator assembly that withstands the pressure generated within the combustion chamber upon reaction of the pyrotechnic material and wherein the shell member is incapable of withstanding the pressure generated within the combustion chamber upon reaction of the pyrotechnic material without support provided by the composite overwrap.

25. An inflator assembly comprising:

a shell member having an inner surface, an outer surface, an open first end and a second end opposite the first end;

an end cap joinable with the shell member to at least in part enclose the open first end of the shell member to form an inflator subassembly, the end cap including mounting provisions for mounting the inflator assembly into an airbag module, the mounting provisions comprising an outwardly extending tab;

a diffuser assembly disposed adjacent the second end of the shell member, the diffuser assembly including a plurality of flow control features for controlling flow of product gas from the inflator assembly, the diffuser assembly including a base having a top surface flush with the outer surface of the shell member; and

an overwrap about at least a portion of the shell member, the base of the diffuser assembly and the end cap to form the inflator assembly that withstands the pressure generated within the inflator assembly, the overwrap comprising a composite of fibers and a resin matrix system.

26. The inflator assembly of claim 25 wherein:

the inflator subassembly contains a quantity of pyrotechnic material and at least in part defines a combustion chamber wherein at least a portion of the quantity of pyrotechnic material is reactable to form product gas for inflation of an associated airbag cushion and to generate pressure within the combustion chamber, and

the end cap at least in part contains an initiator that upon actuation initiates reaction of the pyrotechnic material.

27. The inflator assembly of claim 26 wherein the overwrap about at least a portion of the shell member and the end cap to form the inflator assembly that withstands the pressure generated within the combustion chamber upon reaction of the pyrotechnic material.

28. The inflator assembly of claim 27 additionally comprising:

a diffuser assembly disposed adjacent the second end of the shell member, the diffuser assembly including a plurality of flow control features for controlling flow of product gas from the inflator assembly; and

wherein the overwrap additionally extends about at least a portion of the diffuser assembly in forming the inflator assembly that withstands the pressure generated within the combustion chamber upon reaction of the pyrotechnic material.