Gas generator

• US 9,114,778 B2
• Filed: 02/12/2014
• Issued: 08/25/2015
• Est. Priority Date: 02/18/2013
• Status: Active Grant

• Current Assignee: Daicel Corporation
• Original Assignee: Daicel Corporation
• Inventors: Hanano, Teppei, Yamashita, Haruhiko, Imoto, Katsuhiro
• Primary Examiner(s): Weber, Jonathan C
• Application Number:
  US14/179,367
• Publication Number:
  US 20140230685A1
• Time in Patent Office: 559 Days
• Field of Search: 102/530, 102/531, 280/728.1, 280/741, 280/736, 280/742, 280/740, 280/737
• US Class Current: 1/1
• 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

A gas generator includes a cylindrical housing, a diffuser portion, a first combustion chamber defined by a first porous plate member, a second combustion chamber defined by a second porous plate member, and an ignition device having an ignition portion attached to an igniter collar. The first porous plate member comprises first through holes arranged in the vicinity of a peripheral edge portion. An annular space is formed between an outer peripheral surface of the ignition portion and an inner peripheral wall surface of the cylindrical housing. The height (H) of a top surface of the ignition portion from the igniter collar and a smallest length (Lmin) of a first gas generating agent in the first combustion chamber satisfies a relation Lmin<H. An axis of the cylindrical housing is coincident with a central line of the ignition portion, the first porous plate member, and the second porous plate member.

Claims

1. A gas generator, comprising

a cylindrical housing with an ignition device attached at one end and a diffuser portion, which has a gas discharge port, attached at the other end,

a first combustion chamber formed inside the cylindrical housing at the one end to which the ignition device is attached, being defined by a first porous plate member, and being charged with a molded article of first gas generating agent,

a second combustion chamber formed in the cylindrical housing and defined by a second porous plate member, which is disposed axially at a distance from the first porous plate member and has a second through hole, the second combustion chamber being charged with a molded article of second gas generating agent,

the ignition device provided by fixing an igniter main body with a columnar ignition portion, to a fixing member including an igniter collar, the ignition portion disposed to protrude inside the first combustion chamber,

the first porous plate member having first through holes, a proportion of a first total opening area of only outer first through holes arranged in the vicinity of a peripheral edge portion and in a circumferential direction of the first porous plate member to a total opening area of the first through holes in the first porous plate member being not less than 95%,

axial end surfaces of the first combustion chamber, respectively, formed by the first porous plate member, and the ignition portion of the igniter main body and the igniter collar,

an annular space formed between an outer peripheral surface of the ignition portion and an inner peripheral wall surface of the cylindrical housing, which radially faces the outer peripheral surface of the ignition portion, the annular space having a bottom surface defined by the igniter collar,

a height (H) of a top surface of the ignition portion from the bottom surface and a smallest length (Lmin) of the molded article of first gas generating agent charged in the first combustion chamber satisfying a relation of Lmin<

H, and

an axis X of the cylindrical housing being coincident with a central line of the ignition portion of the igniter main body, the first porous plate member, and the second porous plate member.

2. The gas generator according to claim 1, wherein

H/Lmin is in the range of 2 to 5.

3. The gas generator according to claim 1, wherein

the first porous plate member has the first through holes consisting of only the outer first through holes formed in the circumferential direction and only in the vicinity of the peripheral edge portion thereof.

4. The gas generator according to claim 1, wherein

a ratio (a2/a1) of a total opening area (a2) of the second through hole formed in the second porous plate member and a total opening area (a1) of the first through holes formed in the first porous plate member is between 0.9 and 1.2.

5. The gas generator according to claim 1, wherein

a cylindrical member provided with a communication hole in a peripheral wall portion is further disposed in the second combustion chamber,

the cylindrical member is disposed so as to form a gap between an inner peripheral wall surface of the cylindrical housing and the peripheral wall portion of the cylindrical member, and

the cylindrical member has a first opening end on a side of the second porous plate member, that abuts against the inner peripheral wall surface of the cylindrical housing, and, at the opposite side, a second end that is supported on a side of the diffuser portion.

6. The gas generator according to claim 5, wherein

the cylindrical member includes an enlarged diameter in which a diameter of an opening portion on a side of the first opening end is enlarged and a central hole formed at a center of a bottom surface on a side of the second end,

a cup-like shaped gas diverting member having a communication hole in a peripheral wall portion and a projection on a bottom surface, is disposed on the side of the diffuser portion, whose opening is arranged to face the diffuser portion,

the first opening end of the cylindrical member abuts against the inner peripheral wall surface of the cylindrical housing, and

the central hole of the cylindrical member is fitted to the projection on the bottom surface of the gas diverting member.

7. The gas generator according to claim 5, wherein

the first porous plate member has the first through holes consisting of only the outer first through holes arranged in the circumferential direction only in the vicinity of the peripheral edge portion thereof, and

the second porous plate member has a plurality of second through holes consisting of only outer second through holes arranged in the circumferential direction only in the vicinity of the peripheral edge portion thereof.