Gas generator

• US 7,614,875 B2
• Filed: 08/27/2007
• Issued: 11/10/2009
• Est. Priority Date: 08/28/2006
• Status: Active Grant

• Current Assignee: Daicel Chemical Industries Limited
• Original Assignee: Daicel Chemical Industries Limited
• Inventors: Katsuda, Nobuyuki, Oda, Shingo
• Primary Examiner(s): Rinehart; Kenneth B
• Assistant Examiner(s): PEREIRO, JORGE ANDRES
• Application Number:
  US11/892,770
• Publication Number:
  US 20080063993A1
• Time in Patent Office: 806 Days
• Field of Search: 411/21, 411/22, 411/24, 411/25, 411/32, 411/33, 411/76, 411/77, 411/78, 431/253, 280/728.1, 280/728.2, 280/741, 280/736, 102/530, 102/531, 102/202
• US Class Current: 431/253
• CPC Class Codes: B60R 2021/26011 using a filter through which the inflation gas passes
• CPC Class Codes: B60R 2021/26029 Ignitors
• CPC Class Codes: B60R 21/26 characterised by the inflation fluid source or means to control inflation fluid flow arrangement or mounting thereof to the vehicle B60R21/20; blasting cartridges for producing gas under pressure in general F42B3/04; initiators or igniters therefor F42B3/10

Abstract

A gas generator includes, a housing having a gas discharge port; at least one combustion chamber accommodating a gas generating agent therein; a cylindrical filter disposed between the gas discharge port and the combustion chamber; and at least one ignition device for igniting and combusting the gas generating agent, each device comprising an igniter assembly in which an electric igniter is enclosed and fixed by a metal member and a resin portion. The igniter assembly has, in the resin portion, a holder accommodation space disposed over an opening formed in a bottom portion of the housing, and fixed by a holder inserted from the outside into the opening. An inner wall surface of the holder accommodation space has concave and convex portions that engage convex and concave portions of the holder, so that the igniter assembly is fixed without being welded to the bottom portion of the housing.

Claims

1. A gas generator, comprising:

a housing having a gas discharge port;

a combustion chamber accommodating a gas generating agent therein;

a cylindrical filter disposed between the gas discharge port and the combustion chamber;

an ignition device for igniting and combusting the gas generating agent, the ignition device having an igniter assembly that includes,

an electric igniter,

a metal member provided independently from the housing, and

a resin portion that encloses the igniter and attaches the electric igniter to the metal member;

the resin portion defining

a holder accommodation space and placed on an inner surface of a bottom portion of the housing, such that the holder accommodation space is disposed over an opening formed in the bottom portion of the housing, an inner wall surface of the holder accommodation space having at least one of a concave portion and a convex portion; and

the bottom portion; and

a holder having at least one of a convex portion that engages the concave portion of the resin portion and a concave portion that engages the convex portion of the resin portion when the holder is inserted through the opening and into the holder accommodation space, such that the holder fixes the igniter assembly to the bottom portion of the housing without welding to the bottom portion of the housing.

2. The gas generator according to claim 1, wherein

the holder has an annular substrate and hook portions provided to protrude in at least two locations on the annular substrate, the hook portions are made from an elastic material and have the concave portion and the convex portion, and distal end portions of the hook portions are provided to protrude and expand in the direction of an outer circumferential edge of the annular substrate;

the annular substrate of the holder is inserted from the outside into the opening formed in the bottom portion of the housing; and

the concave and convex portions on the inner wall surface of the holder accommodation space and the convex and concave portions of the hook portions engage with each other, and a force that acts to expand outwardly the distal end sections of the hook portions applies pressure to the inner wall surface of the holder accommodation space.

3. The gas generator according to claim 1, wherein

the holder has a first annular substrate, a second annular substrate that is formed on the first annular substrate and has a diameter smaller than that of the first annular substrate, and hook portions provided to protrude in at least two locations on the second annular substrate, the hook portions are made from an elastic material and have the concave portion and the convex portion, and distal end portions of the hook portions are provided to protrude and expand outwardly in the direction of an outer circumferential edge of the second annular substrate;

a step surface between the first annular substrate and the second annular substrate abuts against an outer surface of the bottom portion of the housing, and the second annular substrate is inserted into the opening formed in the bottom portion of the housing; and

the concave and convex portions on the inner wall surface of the holder accommodation space and the convex and concave portions of the hook portions engage with each other, and a force that acts to expand outwardly the distal end sections of the hook portions applies pressure to the inner wall surface of the holder accommodation space.

4. The gas generator according to claim 1 or 2, further comprising:

a cup member that defines an agent accommodation chamber is provided, the cup member is disposed such that a closed end of the cup member abuts against a top surface of the housing,

wherein a circumferential edge of an open end of the cup member abuts against the igniter collar.

9. The gas generator according to claim 1, further comprising:

an O-ring provided between the resin portion and the bottom portion of the housing.

5. A method of fixing an igniter assembly to a housing of a gas generator without employing a welding method, the method comprising:

preparing an igniter assembly having an electric igniter attached to a metal member, provided independently from the housing, by a resin portion defining a holder accommodation space, an inner wall surface of the holder accommodation space having at least one of a concave portion and a convex portion;

forming an opening for fixing the ignition device in a bottom portion of the housing;

preparing a holder having at least one of a convex portion that engages the concave portion of the resin portion and a concave portion that engages the convex portion of the resin portion;

placing the igniter assembly on an inner surface of the bottom portion of the housing, such that the holder accommodation space is disposed over the opening; and

inserting the holder into the holder accommodation space through the opening from an outside of the bottom portion of the housing to engage the at least one of the concave portion and the convex portion of the holder with the at least one of the convex portion and the concave portion of the inner wall surface of the holder accommodation space to fix the igniter assembly to the inner surface of the bottom portion of the housing.

6. The method of fixing an igniter assembly according to claim 5, wherein

as the holder, one having an annular substrate and hook portions provided to protrude in at least two locations on the annular substrate is used, the hook portions being made from an elastic material and having a concave portion and a convex portion, and distal end portions of the hook portions being provided to protrude and expand in the direction of an outer circumferential edge of the annular substrate;

in the inserting step, the holder is inserted so that the concave and convex portions on the inner wall surface of the holder accommodation space engage with the convex and concave portions of the hook portions, and a force that acts to expand outwardly the distal end sections of the hook portions applies pressure to the inner wall surface of the holder accommodation space.

7. The method of fixing an igniter assembly according to claim 5, wherein

as the holder, one having a first annular substrate, a second annular substrate that is formed on the first annular substrate and has a diameter less than that of the first annular substrate, and hook portions provided to protrude in at least two locations on the second annular substrate is used, the hook portions being made from an elastic material and having a concave portion and a convex portion, and distal end portions of the hook portions being protruded so as to expand in the direction of an outer circumferential edge of the second annular substrate,

in the inserting step, the holder is inserted so that a step surface between the first annular substrate and second annular substrate abut against an outer surface of the bottom portion of the housing and the concave and convex portions on the inner wall surface of the holder accommodation space and the convex and concave portions of the hook portions are engaged with each other, and a force that acts to expand outwardly the distal end sections of the hook portions applies pressure to the inner wall surface of the holder accommodation space.

8. The method for fixing an igniter assembly according to claim 5 or 6, further comprising:

after the inserting step, disposing a cup member that forms an agent accommodation chamber such that a closed end of the cup member abuts against a top surface of the housing and a circumferential edge of an open end of the cup member abuts against the igniter collar.

10. The method according to claim 5, further comprising:

placing an O-ring between the resin portion and the bottom portion of the housing.