Gas generator

• US 8,714,091 B2
• Filed: 03/11/2013
• Issued: 05/06/2014
• Est. Priority Date: 04/02/2012
• Status: Active Grant

• Current Assignee: Daicel Corporation
• Original Assignee: Daicel Corporation
• Inventors: Kobayashi, Tomoharu, Yamazaki, Masayuki, Ukita, Shinichiro
• Primary Examiner(s): TO, TOAN C
• Application Number:
  US13/794,120
• Publication Number:
  US 20130255529A1
• Time in Patent Office: 421 Days
• Field of Search: 280/736, 280/741, 102/530
• US Class Current: 102/530
• CPC Class Codes: B60R 2021/26011 using a filter through which the inflation gas passes
• 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
• CPC Class Codes: C06D 5/00 Generation of pressure gas, e.g. for blasting cartridges, starting cartridges, rockets explosive compositions containing an oxidizer, fuels for rocket engines intended for reaction with an oxidant other than air C06B

Abstract

A gas generator includes, a housing integrated at an upper circumferential wall plate and a lower circumferential wall plate, an ignition device chamber defined by a cup-shaped container disposed at a bottom plate of the housing, a combustion chamber surrounding the ignition device chamber, an annular filter facing a top plate of the housing, and a retainer supporting the filter and including an annular bottom surface supporting a lower surface of the filter and a cylindrical wall surface being press-fitted directly or indirectly to a circumferential wall plate of the housing. A circumferential wall of the cup-shaped container in the vicinity of the bottom surface abuts against or is positioned close to an inner circumferential surface of the filter. During activation, when the housing deforms, the annular filter gas-tightly attaches to the top plate of the diffuser shell, and a combustion gas is discharged radially outward through the filter.

Claims

1. A gas generator, comprising:

a housing including,

a diffuser shell having a top plate and an upper circumferential wall plate provided with a gas discharge port, and

a closure shell having a bottom plate and a lower circumferential wall plate, the diffuser shell and the closure shell

forming an outer shell of the gas generator by joining and integrating the upper circumferential wall plate and the lower circumferential wall plate;

an ignition device chamber provided within the outer shell and defined by a cup-shaped container disposed in a central part at the bottom plate of the closure shell, and accommodates an ignition device therein;

a combustion chamber surrounding the ignition device chamber and charged with a gas generating agent;

an annular filter disposed to face the top plate;

a retainer supporting the annular filter and

including,

an annular bottom surface supporting at least a portion of a lower surface of the annular filter, and

a cylindrical wall surface extending at least in an axial direction of the housing from an outer circumferential edge of the annular bottom surface, the cylindrical wall surface being fixed by being press-fitted directly or indirectly to a circumferential wall plate formed by the upper circumferential wall plate and the lower circumferential wall plate;

a combustion gas passage formed to pass through from an outer circumferential surface of the filter to the gas discharge port; and

the cup-shaped container being disposed such that a bottom surface thereof abutting against or being positioned close to the top plate of the diffuser shell, a circumferential wall thereof in the vicinity of the bottom surface abutting against or being positioned close to an inner circumferential surface of the annular filter,

wherein, during an activation of the gas generator,

when the top plate of the diffuser shell and the bottom plate of the closure shell deform in directions along an axis of the housing, the retainer and the annular filter move such that the annular filter is in gas-tight contact with the top plate of the diffuser shell, and a combustion gas passes through the combustion gas passage to be discharged from the gas discharge port after passing radially outward through the annular filter.

2. The gas generator according to claim 1, wherein

the cylindrical wall surface of the retainer extends toward the top plate of the diffuser shell, and a depression and a protrusion are provided in the circumferential direction at a circumferential edge thereof,

during the activation of the gas generator, when the top plate of the diffuser shell and the bottom plate of the closure shell deform in directions along an axis of the housing, the retainer and the annular filter move toward the top plate of the diffuser shell, and

the protrusion of the cylindrical wall surface of the retainer is abutted against the top plate of the diffuser shell, and the depression of the cylindrical wall surface of the retainer forms combustion gas passages.

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

a cylindrical member disposed within the housing such as to be press-fitted to the lower circumferential wall plate of the closure shell, and such that a gap is formed between the cylindrical member and the top plate of the diffuser shell and also between the cylindrical member and the gas discharge port provided in the upper circumferential wall plate,

wherein the retainer is press-fitted and fixed to the cylindrical member.

4. The gas generator according to claim 1, wherein

the lower surface of the annular filter is supported by the annular bottom surface of the retainer, and the outer circumferential surface of the annular filter is supported by the cylindrical wall surface of the retainer, and

the retainer has a through-hole in the inner circumferential edge side of the annular bottom surface facing the annular filter.

5. The gas generator according to claim 1, wherein

the inner circumferential surface of the annular filter protrudes toward the center axis of the housing beyond an inner circumferential edge of the annular bottom surface of the retainer.

6. A gas generator according to claim 1, wherein, during the activation of the gas generator, the top plate and the bottom plate deform in the directions along the axis of the housing, and the retainer and the annular filter move such that the annular filter is in gas-tight contact with the top plate and the inner circumferential surface of the annular filter faces a space between the bottom surface of the cup-shaped container and the top plate of the diffuser shell.

7. A gas generator according to claim 3, wherein a lower portion of the cylindrical member has a first outer diameter and an upper portion of the cylindrical member has a second outer diameter smaller than the first outer diameter, and the cylindrical member is provided such that the lower portion is press-fitted to the lower circumferential wall plate of the closure shell, and the cylindrical wall surface of the retainer is press-fitted to the upper portion.

8. A gas generator according to claim 2, wherein an upper surface of the annular filter protrudes upward beyond the protrusion of the retainer, before actuation.

9. A gas generator, comprising:

a housing including a top plate, a bottom plate, and a circumferential wall connecting the top plate and the bottom plate;

a cup-shaped container defining therein an ignition device chamber and being provided in a central portion within the housing such that an open end of the cup-shaped container is fixed to the bottom plate and the bottom surface is not fixed to the top wall;

an annular filter disposed to face the top plate such that before an activation of the gas generator, an inner cylindrical surface of the annular filter abuts against a circumferential wall of the cup-shaped container; and

a retainer provided within the housing for supporting the annular filter and defining a combustion chamber therebelow for accommodating a gas generating agent, the retainer including,

an annular bottom surface supporting a portion of a lower surface of the annular filter and provided such that the remaining portion of the lower surface of the annular filter faces the combustion chamber, and

a cylindrical wall surface extending at least in a axial direction of the housing from an outer circumferential edge of the annular bottom surface, the cylindrical wall surface being fixed directly or indirectly to the circumferential wall of the housing,

during the activation of the gas generator, the top plate and the bottom plate deform in directions along an axis of the housing, the retainer and the annular filter moving such that the annular filter is in gas-tight contact with the top plate and a first gap is formed between the bottom surface of the cup-shaped container and the top plate so as for the inner circumferential surface of the annular filter to face the first gap.

10. A gas generator according to claim 9, further comprising:

a cylindrical member disposed within the housing so as to be press-fitted to a lower portion of the circumferential wall of the housing such that a second gap is formed between the cylindrical member and the top plate of the housing and a third gap is formed between the cylindrical member and the circumferential wall of the housing,

wherein the retainer is press-fitted and fixed to the cylindrical member.

11. A gas generator according to claim 10, wherein a lower portion of the cylindrical member has a first outer diameter, and an upper of the cylindrical member has a second outer diameter smaller than the first outer diameter, and the cylindrical member is provided such that the lower portion is press-fitted to the lower portion of the circumferential wall of the housing, and the cylindrical wall surface of the retainer is press-fitted to the upper portion.

12. A gas generator according to claim 9,

wherein, prior to the activation of the gas generator, the cylindrical wall surface of the retainer includes a depression and a protrusion provided in a circumferential direction at a circumferential edge thereof, and an upper surface of the annular filter protrudes upward beyond the protrusion of the retainer, and

wherein the annular filter and the retainer are provided such that when the housing is deformed and the retainer and the annular filter moves toward the top plate of the housing, the protrusion of the cylindrical wall surface of the retainer abuts against the top plate of the housing, and the depression of the cylindrical wall surface of the retainer forms a combustion gas passage.