Dual stage air bag inflator

• US 6,543,805 B2
• Filed: 07/03/2001
• Issued: 04/08/2003
• Est. Priority Date: 03/05/1999
• Status: Expired due to Term

• Current Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: McFarland, Eric R., Mika, Darin P.
• Primary Examiner(s): English, Peter C.
• Application Number:
  US09/898,618
• Publication Number:
  US 20020005636A1
• Time in Patent Office: 644 Days
• Field of Search: 280/736, 280/740, 280/741, 280/742, 102/530, 102/531
• US Class Current: 280/736
• CPC Class Codes: B60R 2021/26094 characterised by fluid flow controlling valves
• CPC Class Codes: B60R 2021/2633 with a plurality of inflation levels
• 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

An inflator (10) includes a housing (20). A first inflation fluid source (240) in the housing (20) is actuatable to effect flow of inflation fluid to inflate an inflatable device. A first actuatable initiator (130) in the housing (20), when energized, effects actuation of the first inflation fluid source (240). A second inflation fluid source (250) in the housing (20) is actuatable to effect flow of inflation fluid to inflate the inflatable device. A second actuatable initiator (152) in the housing (20), when energized, effects actuation of the second inflation fluid source (250). The housing (20) has a fluid passage (90) for directing flow of inflation fluid out of the housing (20) to the inflatable device. The housing (20) deforms due to the pressure of inflation fluid in the housing upon actuation of one or both of the inflation fluid sources (240, 250). The flow area of the fluid passage (90) increases due to deformation of the housing (20) and varies in accordance with the pressure of inflation fluid in the housing.

Claims

1. An apparatus for providing inflation fluid for inflating an inflatable vehicle occupant protection device, said apparatus comprising:

a housing;

a first inflation fluid source in said housing actuatable to effect flow of inflation fluid to inflate the inflatable device;

a first actuatable initiator in said housing for, when energized, effecting actuation of said first inflation fluid source;

a second inflation fluid source in said housing actuatable to effect flow of inflation fluid to inflate the inflatable device; and

a second actuatable initiator in said housing for, when energized, effecting actuation of said second inflation fluid source;

said housing having a fluid passage for directing flow of inflation fluid out of said housing to the inflatable device;

said housing further having a first combustion chamber extending completely around a second combustion chamber, said first inflation fluid source being located in said first combustion chamber and said second inflation fluid source being located in said second combustion chamber, said first combustion chamber being generally ring-shaped and said second combustion chamber being generally kidney-shaped;

said housing deforming due to the pressure of inflation fluid in said housing upon actuation of one or both of said inflation fluid sources;

the flow area of said fluid passage increasing due to deformation of said housing and varying in accordance with the pressure of inflation fluid in said housing.

2. An apparatus as set forth in claim 1 further comprising a flow control member defining a control passage located between said inflation fluid sources and said fluid passage, said control passage having a smaller flow area than said fluid passage, the flow area of said control passage increasing due to deformation of said housing and varying in accordance with the pressure of inflation fluid in said housing upon actuation of one or both of said inflation fluid sources.

3. An apparatus as set forth in claim 2 wherein said control passage comprises a plurality of fluid flow control openings which move relative to said housing to increase their flow area upon deformation of said housing.

4. An apparatus as set forth in claim 2 wherein said housing includes first and second housing parts which move relative to each other to vary the flow area of said fluid passage, said flow control member being movable with said first housing part relative to said second housing part, upon actuation of one or both of said inflation fluid sources, to move said control passage from a closed condition to an open condition.

5. An apparatus as set forth in claim 4 wherein said first combustion chamber is centered on an axis, and said second combustion chamber is not centered on said axis.

6. An apparatus as set forth in claim 1 wherein said first combustion chamber is centered on an axis, and said second combustion chamber is not centered on said axis.

7. An apparatus for inflating an inflatable vehicle occupant protection device, said apparatus comprising:

a housing having a first combustion chamber extending completely around a second combustion chamber, said first combustion chamber being generally ring-shaped and said second combustion chamber being generally kidney-shaped;

a first inflation fluid source in said first combustion chamber actuatable to effect flow of inflation fluid to inflate the inflatable device;

a first actuatable initiator for, when energized, effecting actuation of said first inflation fluid source;

a second inflation fluid source in said second combustion chamber actuatable to effect flow of inflation fluid to inflate the inflatable device; and

a second actuatable initiator for, when energized, effecting actuation of said second inflation fluid source.

8. An apparatus as set forth in claim 7 wherein said housing has a fluid passage for directing flow of inflation fluid out of said housing to the inflatable device, said housing deforming due to the pressure of inflation fluid in said housing upon actuation of one or both of said inflation fluid sources, the flow area of said fluid passage increasing due to deformation of said housing and varying in accordance with the pressure of inflation fluid in said housing.

9. An apparatus as set forth in claim 8 further comprising a flow control member defining a control passage located between said inflation fluid sources and said fluid passage, said control passage having a smaller flow area than said fluid passage, the flow area of said control passage increasing due to deformation of said housing and varying in accordance with the pressure of inflation fluid in said housing upon actuation of one or both of said inflation fluid sources.

10. An apparatus as set forth in claim 9 wherein said control passage comprises a plurality of fluid flow control openings which move relative to said housing to increase their flow area upon deformation of said housing.

11. An apparatus for providing inflation fluid for inflating an inflatable vehicle occupant protection device, said apparatus comprising:

a housing;

a first inflation fluid source in said housing actuatable to effect flow of inflation fluid to inflate the inflatable device;

a first actuatable initiator in said housing for, when energized, effecting actuation of said first inflation fluid source;

a second inflation fluid source in said housing actuatable to effect flow of inflation fluid to inflate the inflatable device;

a second actuatable initiator in said housing for, when energized, effecting actuation of said second inflation fluid source;

said housing having a fluid passage for directing flow of inflation fluid out of said housing to the inflatable device;

said housing deforming due to the pressure of inflation fluid in said housing upon actuation of one or both of said inflation fluid sources;

the flow area of said fluid passage increasing due to deformation of said housing and varying in accordance with the pressure of inflation fluid in said housing;

a heat sink being located in said housing between said first inflation fluid source and said fluid passage; and

a retainer for preventing material of said heat sink from being forced toward said fluid passage upon actuation of one or both of said inflation fluid sources, said retainer being located between said heat sink and said fluid passage.

12. An apparatus for providing inflation fluid for inflating an inflatable vehicle occupant protection device, said apparatus comprising:

a housing;

a first inflation fluid source in said housing actuatable to effect flow of inflation fluid to inflate the inflatable device;

a first actuatable initiator in said housing for, when energized, effecting actuation of said first inflation fluid source;

a second inflation fluid source in said housing actuatable to effect flow of inflation fluid to inflate the inflatable device; and

a second actuatable initiator in said housing for, when energized, effecting actuation of said second inflation fluid source;

said housing having exit openings and a fluid passage for directing flow of inflation fluid to said exit openings from which the inflation fluid flows out of said housing to the inflatable device;

said housing further having a first combustion chamber extending completely around a second combustion chamber, said first inflation fluid source being located in said first combustion chamber and said second inflation fluid source being located in said second combustion chamber;

said housing deforming due to the pressure of inflation fluid in said housing upon actuation of one or both of said inflation fluid sources;

the flow area of said fluid passage increasing due to deformation of said housing and varying in accordance with the pressure of inflation fluid in said housing; and

a filter located downstream of said fluid passage and upstream of said exit openings.

13. An apparatus for providing inflation fluid for inflating an inflatable vehicle occupant protection device, said apparatus comprising:

a housing;

a first inflation fluid source in said housing actuatable to effect flow of inflation fluid to inflate the inflatable device;

a first actuatable initiator in said housing for, when energized, effecting actuation of said first inflation fluid source;

a second inflation fluid source in said housing actuatable to effect flow of inflation fluid to inflate the inflatable device; and

a second actuatable initiator in said housing for, when energized, effecting actuation of said second inflation fluid source;

said housing having exit openings and structure in the housing to direct flow of inflation fluid to said exit openings from which the inflation fluid flows out of said housing to the inflatable device;

said housing further having a first combustion chamber extending completely around a second combustion chamber, said first inflation fluid source being located in said first combustion chamber and said second inflation fluid source being located in said second combustion chamber; and

a filter located downstream of said first and second inflation fluid sources and upstream of said exit openings.

14. An air bag inflator comprising:

a housing, a plurality of inflation fluid outlets extending through the housing for enabling inflation fluid to exit the inflator;

primary and secondary propellant chambers located within the housing, the primary propellant chamber including a first solid propellant that is ignitable to provide inflation fluid and the secondary propellant chamber including a second solid propellant that is ignitable to provide inflation fluid;

a primary ignition device for igniting the first propellant and a secondary ignition device for actuating the second propellant; and

a filter encircling the primary ignition device and the secondary propellant chamber, the filter contacting the first propellant to block movement of the first propellant within the primary propellant chamber,

ignition of the first propellant providing inflation fluid which flows through the filter prior to exiting the inflator through the plurality of inflation fluid outlets and ignition of the second propellant providing inflation fluid which flows through the primary propellant chamber and through the filter prior to exiting the inflator through the plurality of inflation fluid outlets.

15. The air bag inflator as set forth in claim 14 wherein the filter extends completely across a flow passage that provides fluid communication between the primary propellant chamber and the inflation fluid outlets.

16. The air bag inflator as set for in claim 14 wherein the filter has an annular configuration.

17. The air bag inflator as set for in claim 16 wherein the annular configuration of the filter is defined by inner and outer diameters, the outer diameter of the annular configuration of the filter contacting a radially outer wall of the primary propellant chamber.

18. The air bag inflator as set forth in claim 14 wherein the filter comprises metal wire.

19. The air bag inflator as set forth in claim 14 further including closure means for closing the primary propellant chamber, inflation fluid pressure resulting from ignition of at least the first propellant opening the closure means for enabling inflation fluid flow out of the primary propellant chamber and through the inflation fluid outlets.

20. The air bag inflator as set forth in claim 14 further including a retainer that extends across at least a portion of the primary propellant chamber and contacts the filter for helping to position the filter.

21. The air bag inflator as set forth in claim 14 further including a cap extending completely over the primary propellant chamber for directing inflation fluid flow from the primary propellant chamber toward the inflation fluid outlets.

22. An air bag inflator comprising:

a housing, a plurality of inflation fluid outlets extending through the housing for enabling inflation fluid to exit the inflator;

primary and secondary propellant chambers located within the housing, the primary propellant chamber including a first solid propellant that is ignitable to provide inflation fluid and the secondary propellant chamber including a second solid propellant that is ignitable to provide inflation fluid;

primary and secondary ignition chambers located within the housing and laterally adjacent one another, the primary propellant chamber being located laterally outward of and encircling the primary and second ignition chambers, the primary ignition chamber including a first ignitable material and means for igniting the first ignitable material, combustion products resulting from ignition of the first ignitable material igniting the first propellant, the secondary ignition chamber including means for igniting the second propellant, the primary ignition chamber including a plurality of ports for directing combustion products resulting from ignition of the first ignitable material toward the first propellant; and

structure covering the plurality of ports in the primary ignition chamber prior to ignition of the first ignitable material, the structure being removed from covering the plurality of ports by the combustion products of the first ignitable material to enable flow of the combustion products resulting from ignition of the first ignitable material through the plurality of ports toward the first propellant.

23. The air bag inflator as set forth in claim 22 wherein the primary propellant chamber also encircles the secondary propellant chamber.

24. The air bag inflator as set forth in claim 22 further including a filter, inflation fluid resulting from ignition of the first and second propellants flowing through the filter prior to exiting the housing through the inflation fluid outlets.

25. The air bag inflator as set forth in claim 24 further including a cap that extends completely over the primary propellant chamber and at least partially over the filter to help position the filter.

26. An air bag inflator comprising:

a housing having a plurality of exit openings for enabling inflation fluid out of the inflator;

primary and secondary propellant chambers located within the housing, a first inflation fluid source located in the primary propellant chamber and actuatable to effect flow of inflation fluid through the plurality of exit openings, a second inflation fluid source located in the secondary propellant chamber and actuatable to effect flow of inflation fluid through the primary propellant chamber and through the plurality of exit openings;

the first inflation fluid source and the second inflation fluid source comprising solid pyrotechnic material which, when ignited, generates inflation fluid;

a first initiator associated with the primary propellant chamber for, when energized, actuating the first inflation fluid source;

a second initiator associated with the secondary propellant chamber, for when energized, actuating the second inflation fluid source;

a filter in the housing through which inflation fluid generated by at least the first inflation fluid source flows, and

a cap in the housing extending completely over the primary propellant chamber and at least partially over the filter and having a portion to help position the filter.

27. The air bag inflator as set forth in claim 26 wherein the filter extends completely across a flow passage that provides fluid communication between the primary propellant chamber and the exit openings.

28. The air bag inflator as set forth in claim 26 wherein the first initiator including a first ignitable material and means for igniting the first ignitable material, combustion products resulting from ignition of the first ignitable material igniting the first inflation fluid source, the second initiator including means for igniting the second inflation fluid source, the first initiator having a housing that includes a plurality of ports for directing combustion products resulting from ignition of the first ignitable material toward the first inflation fluid source.

29. An air bag inflator comprising:

a housing having a plurality of exit openings for enabling flow of inflation fluid out of the inflator, said housing having a form of a flattened cylinder and being sized for driver side placement within a vehicle, said housing including upper and lower cup-shaped housing parts which have annular side walls welded together and end walls opposite each other, said exit openings being in one of said side walls and being spaced apart from other around said one of said side walls;

primary and secondary propellant chambers located within the housing, a first solid pyrotechnic material located in the primary propellant chamber and ignitable to generate inflation fluid which flows through the plurality of exit openings, a second solid pyrotechnic material located in the secondary propellant chamber and ignitable to generate inflation fluid which flows through the primary propellant chamber and through the plurality of exit openings;

a first initiator associated with the primary propellant chamber for, when energized, actuating the first solid pyrotechnic material;

a second initiator associated with the secondary propellant chamber for, when energized, igniting the second solid pyrotechnic material;

an annular filter in the housing, located inside the annular side walls that are welded together, and through which inflation fluid generated by at least one of the first and second pyrotechnic materials flows; and

structure interposed between the end wall of said lower cup-shaped housing part and said first and second initiators and supporting said first and second initiators.

30. The air bag inflator as set forth in claim 29 wherein said end wall of said lower cup-shaped housing part includes a circular opening, said structure including a cylindrical portion that extends into said circular opening.

31. The air bag inflator as set forth in claim 30 wherein said structure includes a mounting portion that extends radially outwardly of said cylindrical portion and engages an inner surface of said end wall of said lower cup-shaped housing part.