Pyrotechnic linear inflator

• US 20050151358A1
• Filed: 01/12/2005
• Published: 07/14/2005
• Est. Priority Date: 01/13/2004
• Status: Active Grant

• Current Assignee: Automotive Systems Laboratory, Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: Automotive Systems Laboratory, Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Burns, Sean P., Quioc, Eduardo L., Stevens, Bruace A.
• Granted Patent: US 7,080,854 B2
• Time in Patent Office: Days
• US Class Current: 280/741
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder

Abstract

An inflator (10) for use in an inflatable vehicle occupant protection system. In one aspect of the invention, the inflator (10) includes a longitudinal enclosure (22) having a substantially uniform cross-sectional area along at least a portion of the enclosure, and a gas generant composition (24) positioned along the portion of the enclosure (22). The gas generant composition (24) is distributed substantially uniformly along the portion of the enclosure (22). A plurality of gas exit apertures (40) is formed along the portion of the enclosure (22) to enable fluid communication between the enclosure (22) and an exterior of the enclosure. The apertures (40) are spaced apart a distance proportional to a desired rate of propagation of a combustion reaction of gas generant positioned between the apertures (40). In another aspect of the invention, the inflator (10) includes a longitudinal enclosure (22) having a substantially uniform cross-sectional area along at least a portion of the enclosure, and a gas generant composition (24) positioned along the portion of the enclosure (22). The gas generant composition (24) is distributed substantially uniformly along the portion of the enclosure (22). A plurality of gas exit apertures (40) is formed along the portion of the enclosure (22) to enable fluid communication between the enclosure (22) and an exterior of the enclosure. The total number of apertures (40) along the enclosure (22) is inversely proportional to a desired rate of propagation of a combustion reaction of gas generant positioned between the apertures (40).

Claims

1. An inflator for use in an inflatable vehicle occupant protection system comprising:

a longitudinal enclosure having a substantially uniform cross-sectional area along at least a portion of the enclosure, wherein said longitudinal enclosure comprises a first perforated section and a second perforated section, said first perforated section containing a first gas exit aperture area and said second perforated section containing a second gas exit aperture area, said second gas exit aperture area greater than said first gas exit aperture area;

a gas generant composition positioned within the at least a portion of the enclosure, the gas generant composition being distributed substantially uniformly along the at least a portion of the enclosure; and

an igniter operably fixed to said first perforated section for ignition of said gas generant composition upon inflator activation.

2. The inflator of claim 1 wherein the first and second gas exit aperture areas are formed by a first plurality of gas exit apertures being formed along the at least a portion of the enclosure to enable fluid communication between the enclosure and an exterior of the enclosure, the apertures of the first plurality of gas exit apertures being spaced apart a distance proportional to a desired rate of combustion propagation of gas generant positioned between the apertures, the enclosure including an inner diameter.

3. The inflator of claim 2 wherein each of the first plurality of gas exit apertures are spaced on center about six millimeters to 26 or more millimeters from an adjoining gas exit aperture, and, wherein each of the first plurality of gas exit apertures are sized from one millimeter to one half the diameter of the enclosure.

4. The inflator of claim 1 wherein the gas generant is in the form of a plurality of adjacent gas generant tablets positioned along the at least a portion of the enclosure and the gas generant tablets are dome-shaped so as to provide a cavity between adjacent ones of the at least a portion of the gas generant tablets.

5. The inflator of claim 2 wherein the gas exit apertures formed along the at least a portion of the enclosure are substantially collinear.

6. An inflator for use in an inflatable vehicle occupant protection system comprising:

a longitudinal enclosure having a substantially uniform cross-sectional area along at least a portion of the enclosure, wherein said longitudinal enclosure comprises a first perforated section and a second perforated section, said first perforated section containing a first gas exit aperture area and said second perforated section containing a second gas exit aperture area, said second gas exit aperture area greater than said first gas exit aperture area;

a gas generant composition positioned within the at least a portion of the enclosure, the gas generant composition being distributed substantially uniformly along the at least a portion of the enclosure; and

an igniter operably fixed to said first perforated section for ignition of said gas generant composition upon inflator activation;

wherein said first and second open aperture areas enable fluid communication between the enclosure and an exterior of the enclosure, first open aperture area inversely proportional to a desired rate of propagation of a combustion reaction of said gas generant positioned within said enclosure.

7. A method for controlling a rate of propagation of a combustion reaction along at least a portion of a longitudinal enclosure comprising the steps of;

providing a longitudinal enclosure having a substantially uniform cross-sectional area along the at least a portion of the enclosure, and a first plurality of gas exit apertures formed along the at least a portion of the enclosure to enable fluid communication between the enclosure and an exterior of the enclosure,

providing a gas generant composition positioned along the at least a portion of the enclosure, the gas generant composition being distributed substantially uniformly along the at least a portion of the enclosure,

wherein the apertures of the first plurality of gas exit apertures are spaced apart a distance corresponding to a desired rate of propagation of a combustion reaction of gas generant positioned between the apertures.

8. The method of claim 7 wherein the step of providing an enclosure having a first plurality of gas exit apertures comprises the step of spacing apart the apertures of the first plurality of apertures substantially evenly along the at least a portion of the enclosure.

9. The method of claim 7 wherein the step of providing an enclosure having a first plurality of gas exit apertures comprises the step of collinearly positioning the apertures of the first plurality of apertures.

10. The method of claim 7 further comprising the steps of:

providing a second plurality of gas exit apertures formed along another portion of the enclosure different from the at least a portion of the enclosure, to enable fluid communication between the enclosure and an exterior of the enclosure;

providing a gas generant composition positioned along the other portion of the enclosure, the gas generant composition being distributed substantially uniformly along the other portion of the enclosure,

wherein the apertures of the second plurality of gas exit apertures are spaced apart a distance corresponding to a desired rate of propagation of a combustion reaction of the gas generant positioned along the other portion of the enclosure.

11. A vehicle occupant restraint system comprising:

an airbag system having at least one airbag and an inflator coupled to the airbag so as to enable fluid communication with an interior of the airbag upon activation of the inflator, the inflator including;

a longitudinal enclosure having a substantially uniform cross-sectional area along at least a portion of the enclosure, wherein said longitudinal enclosure comprises a first perforated section and a second perforated section, said first perforated section containing a first gas exit aperture area and said second perforated section containing a second gas exit aperture area, said second gas exit aperture area greater than said first gas exit aperture area;

a gas generant composition positioned within the at least a portion of the enclosure, the gas generant composition being distributed substantially uniformly along the at least a portion of the enclosure; and

an igniter operably fixed to said first perforated section for ignition of said gas generant composition upon inflator activation.