Dual-wall pyrotechnic air bag inflator with tortuous gas flow

• US 5,582,427 A
• Filed: 06/28/1995
• Issued: 12/10/1996
• Est. Priority Date: 06/28/1995
• Status: Expired due to Fees

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Morton International Incorporated (Autoliv Incorporated)
• Inventors: Parker, John N., Smith, Bradley W., Jackson, Scott A., Parker, Todd S., Rink, Linda M., Fulmer, Brian H.
• Primary Examiner(s): Johnson, Brian L.
• Assistant Examiner(s): English, Peter C.
• Application Number:
  US08/496,041
• Time in Patent Office: 531 Days
• Field of Search: 280/741, 280/740, 280/736, 280/742, 102/530, 102/531, 422/164, 422/165, 422/166
• US Class Current: 280/740
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder

Abstract

A dual-walled air bag inflator having a filter and gas generant within a common chamber, with the gas exiting radially from the inflator. Various arrangements are provided to force the generated gas to change its direction of travel at least 90° prior to exiting in order to slow the gas and improve filtration. Gas barriers are placed within the chamber to force the desired flow. The gas flow may be directed radially inward in opposed streams to cancel velocity, and then directed radially outward toward the filter and exits. In one embodiment a mixing chamber is provided for the gas prior to encountering the filter.

Claims

1. A dual-wall pyrotechnic air bag inflator, comprising:

a housing including;

spaced, opposed top and bottom walls, a tubular inner wall defining a longitudinal axis, a tubular outer wall coaxial with said inner wall, said inner and outer walls extending between said top and bottom walls to define a cylindrical ignition chamber within said inner wall and an annular generant chamber between said inner and outer walls, said inner wall including a plurality of ignition ports and said outer wall including a plurality of exit ports, and wherein said ignition chamber is divided into discrete initiating and mixing compartments, said initiating and mixing compartments having no direct gas communication therebetween;

ignition means mounted within said ignition chamber, within said initiating compartment;

a mass of generant for creating an inflation gas received within said generant chamber;

a filter received in said generant chamber, said filter having an entrance face and an exit face, said exit face being in communication with said exit ports;

a plurality of channel ports and primary ports in said inner wall, said primary ports communicating between said initiating compartment and said mass of generant, said ignition ports communicating between said mass of generant and said mixing compartments, and said channel ports communicating between said mixing compartments and said entrance face of said filter; and

a seal longitudinally and directly interposed between said mass of generant and said filter said seal extending the entire radial span of said generant chamber.

2. An inflator as in claim 1, wherein said ignition means includes a mass of initiating material held within a container, said container having an upper face which divides said ignition chamber into said initiating and mixing compartments.

3. An inflator as in claim 1, further including a frangible seal blocking said ignition ports.

4. An inflator as in claim 3, further including a frangible seal blocking said channel ports.

5. An inflator as in claim 1, further including a frangible seal blocking said channel ports.

6. A dual-wall pyrotechnic air bag inflator, comprising:

a housing including;

spaced, opposed top and bottom walls, a tubular inner wall defining a longitudinal axis, a tubular outer wall coaxial with said inner wall, said inner and outer walls extending between said top and bottom walls to define a cylindrical ignition chamber within said inner wall and an annular generant chamber between said inner and outer walls, said inner wall including a plurality of ignition ports and said outer wall including a plurality of exit ports;

ignition means mounted within said ignition chamber;

a mass of generant for creating an inflation gas received within said generant chamber;

a filter received in said generant chamber, said filter having an entrance face and an exit face, said exit face being in communication with said exit ports, and said entrance face being in direct communication with said mass of generant and radially interior of a substantial portion of said mass of generant; and

a seal longitudinally and directly interposed between said mass of generant and said filter, and with said filter interposed between said seal and said top wall, a plurality of seal ports extending through said seal, said seal ports being spaced from said top wall a distance less than a distance between said exit ports and said top wall, and said seal further including a radially inner edge and a support leg extending from said inner edge to said top wall.

7. An inflator as in claim 6, wherein said seal further includes, intermediate said radially inner edge and a radially outer edge, a vertical offset in the form of a tube coaxial with said walls, and wherein said filter further includes a longitudinal extension portion, said longitudinal extension portion of said filter being interposed between said vertical offset and said exit ports.