Dual stage inflator

• US 20040195813A1
• Filed: 04/01/2003
• Published: 10/07/2004
• Est. Priority Date: 04/01/2003
• Status: Active Grant

• Current Assignee: Key Safety Systems, Inc. (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: Key Safety Systems, Inc. (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Canterberry, J B, Bowers, Donald
• Granted Patent: US 6,886,856 B2
• Time in Patent Office: Days
• US Class Current: 280/741
• 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 for inflating an airbag has a housing with a first housing portion defining a first chamber and a second housing portion defining a second chamber. A gas generant disposed in the first and second chambers. A barrier separates the first and second chambers. Each of the chambers has an ignition enhancer tube disposed therein with a portion of an ignition unit being located therein. Each of the ignition enhancer tubes has at least one outlet defined therein. Each ignition enhancer tube holding an ignition enhancer such that when the associated ignition unit ignites the ignition enhancer combusts and exits through said outlet and then reacts with the gas generant in the associated chamber.

Claims

1. An inflator for inflating an airbag comprising:

a housing having an axial centerline and comprising a first housing portion with a diameter d1, said first housing portion defining a first chamber, said housing further comprising a second housing portion with a diameter d2, said second housing portion defining a second chamber;

a gas generant disposed in said first and second chambers;

a first ignition unit for use in combusting said gas generant disposed in said first chamber;

a second ignition unit for use in combusting said gas generant disposed in said second chamber;

a barrier extending perpendicular to the axis of the inflator and separating the first and second chambers;

a first ignition enhancer tube disposed in said first chamber, a portion of said ignition unit being located within said first ignition enhancer tube, said first ignition enhancer tube having at least one outlet defined therein, said first ignition enhancer tube capable of holding an ignition enhancer such that when said ignition unit ignites, said ignition enhancer combusts and exits through said outlet and then reacts with said gas generant; and

a second ignition enhancer tube disposed in said second chamber, a portion of said ignition unit being located within said second ignition enhancer tube, said second ignition enhancer tube having at least one outlet defined therein, said second ignition enhancer tube capable of holding an ignition enhancer such that when said ignition unit ignites, said ignition enhancer combusts and exits through said outlet and then reacts with said gas generant.

2. The inflator of claim 1 further comprising:

a first filter radially spaced from said first ignition unit and disposed between said gas generant and a gas exit port through said first housing portion; and

a second filter radially spaced from said second ignition unit and disposed between said gas generant and a gas exit port through said second housing portion.

3. The inflator of claim 1 wherein said barrier extending perpendicular to the axis of the inflator comprises a first divider plate connected to said first housing portion and a second divider plate connected to said second housing portions.

4. The inflator of claim 3 wherein said first divider plate comprises:

a main body;

inner and outer annular ribs integrally formed with said main body and forming cavities thereunder; and

a circumferentially extending flange portion contacting said second divider plate and said first housing portion.

5. The inflator of claim 3 wherein the said second divider plate further comprises:

a main body having a circumferentially extending flange portion;

inner and outer annular ribs integrally formed with said main body and forming cavities thereunder; and

an circumferentially extending rim surrounding said circumferentially extending flange portion such that said circumferentially extending rim contacts an interior wall of said second housing chamber.

6. The inflator of claim 1 wherein the housing portions are sized such that such that d1 is different than d2

7. The inflator of claim 1, wherein said first and second igniters further comprise:

an igniter retainer attached to each respective housing portion; and

an igniter attached to said igniter retainer, wherein activation of said igniter causes said gas generant to combust.

8. The inflator of claim 1, wherein said first chamber has a first volume and said second chamber has a second volume such that the volume of the first chamber is substantially equal to the volume of the second chamber.

9. The inflator of claim 1, said first chamber has a first volume and said second chamber has a second volume such that the volume of the first chamber is less than the volume of the second chamber.

10. The inflator of claim 9, wherein said volume of the first chamber ranges from substantially 50% to 80% of the total inflator volume.

11. The inflator of claim 10, wherein said the volume of the first chamber is in the range of substantially 50% to 70% of a total inflator volume.

17. The inflator of claim 11, wherein said first housing portion has an exterior diameter d1, and said second housing portion has an exterior diameter d2, wherein d1 is different than d2.

12. An inflator for use in inflating an airbag comprising:

a first housing portion having a first chamber defined therein;

a second housing portion having a second chamber defined therein and being adjacent to said first housing portion, said first and second housing portions having a separating barrier between said first and second housing portions;

a gas generant disposed in said first and second chambers;

at least one gas exit port defined in said first housing portion;

at least one gas exit port defined in said second housing portion;

a first igniter disposed in said first chamber;

a second igniter disposed in said second chamber, wherein when said first and second igniter are activated, said gas generant combusts and associated gas resulting therefrom exits said first and second housing portions via said gas exit ports to inflate an associate airbag; and

an enhancer tube attached to said first housing portion and said separating wall, said enhancer tube located in the center of first chamber and defining a cavity therein to enclose said first igniter and an ignition enhancer.

13. The inflator of claim 12, further comprising a filter disposed in said first chamber between said gas generant and said gas exit port.

14. The inflator of claim 12, said first chamber has a first volume and said second chamber has a second volume such that the volume of the first chamber is less than the volume of the second chamber.

15. The inflator of claim 12 wherein the exterior of the inflator has a maximum diameter Dmax and a height h forming a ratio of Dmax/h, said ratio Dmax/h within the range of substantially 1.00 to substantially 3.00;

16. The inflator of claim 15, wherein said ratio Dmax/h is substantially 2.0.

18. An inflator for an automotive airbag comprising:

a first housing portion defining a first chamber, said first housing portion having a first divider plate attached thereto;

a second housing portion defining a second chamber, said second housing portion having a second divider plate attached thereto, said first and second divider plates forming a separating wall between said first and second housing portions, said first divider plate comprising a main body having a circumferentially extending flange portion, inner and outer annular ribs integrally formed with said main body and forming cavities thereunder, and an circumferentially extending rim surrounding said circumferentially extending flange portion such that circumferentially extending rim contacts an interior wall of said first housing chamber during assembly, said second divider plate further comprising a main body, inner and outer annular ribs integrally formed with said main body and forming cavities thereunder, and a circumferentially extending flange portion contacting said first divider plate and said second housing portion;

a maximum diameter and a height forming a ratio of Dmax/h, said ration Dmax/h ranging from substantially 1.00 to 3.00;

a gas generant disposed in said first and second chambers;

a first ignition unit disposed in said first chamber; and

a second ignition unit disposed in said second chamber;

a plurality of gas exit ports defined in said first housing portion and said second housing portion;

a first filter radially spaced from said first ignition unit and disposed between said gas generant and said plurality of gas exit ports of said second housing portion;

a second filter radially spaced from said second ignition unit and disposed between said gas generant and said plurality of gas exit ports of said second housing portion;

a first ignition enhancer tube disposed in said first chamber, a portion of said ignition unit being located within said first ignition enhancer tube, said first ignition enhancer tube having a plurality of openings defined therein, said first ignition enhancer tube capable of holding an ignition enhancer;

a second ignition enhancer tube disposed in said second chamber, a portion of said ignition unit being located within said second ignition enhancer tube, said second ignition enhancer tube having a plurality of openings defined therein, said second ignition enhancer tube capable of holding an ignition; and

first and second igniters each comprising;

an igniter retainer attached to a respective housing portion; and

an igniter attached to said igniter retainer, wherein activation of said igniter causes said gas generant to combust, such that when said igniters ignites, said ignition enhancer combusts and exits through said plurality of openings and then reacts with said gas generant, whereby gas resulting from combustion of said gas generant is not forced to turn at angle greater than or equal to ninety degrees before exiting said plurality of gas exit ports.