Gas generator

Patent metadata

Field	Value
Publication number	US-10625706-B2
Application number	US-201716314750-A
Country	US
Kind code	B2
Filing date	Jul 3, 2017
Priority date	Jul 20, 2016
Publication date	Apr 21, 2020
Grant date	Apr 21, 2020

Abstract

The present invention provides a gas generator, including: a cylindrical housing; an ignition device installed at a first end of the cylindrical housing, and a diffuser portion installed at a second end thereof; a flow channel forming member disposed inside the cylindrical housing and including a partition wall which separates a first chamber from a second chamber; a combustion chamber formed in the first chamber; a discharge passage formed in the second chamber; a first cylindrical space formed on the outside of the first circumferential wall and a first communication hole formed in the first circumferential wall; a second cylindrical space formed on the outside of the second circumferential wall and being in communication with the first cylindrical space, and a second communication hole formed in the second circumferential wall; a cylindrical filter disposed in the second cylindrical space; an outer diameter (d 1 ) of the first circumferential wall, an outer diameter (d 2 ) of the second circumferential wall and an outer diameter (d 3 ) of the cylindrical filter satisfying relationships of d 1 >d 2 and d 1 ≥d 3 ; and between the cylindrical filter and the inner wall surface of the cylindrical housing, the second cylindrical space facing the second communication hole via the cylindrical filter.

First claim

The invention claimed is:

1. A gas generator, comprising:
a cylindrical housing;
an ignition device installed at a first end of the cylindrical housing, and a diffuser portion provided with a gas discharge port and installed at a second end on an opposite side to the first end;
a cylindrical flow channel forming member disposed inside the cylindrical housing such that a first end thereof faces the ignition device and a second end thereof on an opposite side to the first end faces the diffuser portion, the cylindrical flow channel forming member including a partition wall which separates a first chamber defined by a first circumferential wall on the side of the first end, from a second chamber defined by a second circumferential wall on the side of the second end;
a combustion chamber formed in the first chamber and charged with a gas generating agent which generates a combustion gas;
a discharge passage formed in the second chamber and allowing the combustion gas to flow to the diffuser portion;
a first cylindrical space formed between the first circumferential wall and an inner wall surface of the cylindrical housing, and a first communication hole formed in the first circumferential wall and communicating the combustion chamber with the first cylindrical space;
a second cylindrical space formed between the second circumferential wall and the inner wall surface of the cylindrical housing and being in communication with the first cylindrical space in an axial direction, and a second communication hole formed in the second circumferential wall and communicating the second cylindrical space with the discharge passage; and
a cylindrical filter disposed in the second cylindrical space and enclosing the second communication hole,
an outer diameter (d 1 ) of the first circumferential wall and an outer diameter (d 2 ) of the second circumferential wall satisfying a relationship of d 1 >d 2 so that an annular stepped surface is formed between the first circumferential wall and the second circumferential wall, and the outer diameter (d 1 ) of the first circumferential wall and an outer diameter (d 3 ) of the cylindrical filter satisfying d 1 ≥d 3 , and
between the cylindrical filter and the inner wall surface of the cylindrical housing, the second cylindrical space facing the second communication hole via the cylindrical filter.

2. A gas generator, comprising:
an ignition device installed on the side of a first end of a cylindrical housing, and a diffuser portion provided with a gas discharge port and installed on the side of a second end on an opposite side in an axial direction to the first end;
an annular end surface at the second end, which is in contact with an inner wall surface of the cylindrical housing, being formed between the second end of the cylindrical housing and the diffuser portion;
a cylindrical flow channel forming member disposed from the side of the first end toward the second end inside the cylindrical housing,
an internal space of the cylindrical flow channel forming member being partitioned by a partition wall into a first chamber on the side of the first end and a second chamber on the side of the second end;
a space, which includes the first chamber inside the cylindrical flow channel forming member, being a combustion chamber charged with a gas generating agent and the second chamber inside the cylindrical flow channel forming member forming part of a gas discharge passage which allows a combustion gas generated by combustion of the gas generating agent to flow toward the diffuser portion;
the cylindrical flow channel forming member having a first circumferential wall facing the first chamber and a second circumferential wall facing the second chamber;
in the cylindrical flow channel forming member, an upstream end of the flow channel forming member on an upstream side of a flow of the combustion gas toward the gas discharge port during actuation being positioned on the side of the first end of the cylindrical housing, a downstream end of the flow channel forming member on a downstream side of the flow of the combustion gas being positioned on the side of the second end of the cylindrical housing, and the downstream end being abutted against the annular end surface;
a first cylindrical space being formed between the first circumferential wall and the inner wall surface of the cylindrical housing, a second cylindrical space being formed between the second circumferential wall and the inner wall surface of the cylindrical housing, and the first cylindrical space and the second cylindrical space being arranged so as to form a continuous space in the axial direction;
a plurality of first communication holes being formed in the first circumferential wall and a plurality of second communication holes being formed in the second circumferential wall;
a cylindrical filter which encloses the second communication holes being disposed in the second cylindrical space;
an outer diameter (d 1 ) of the first circumferential wall on the side of the first chamber and an outer diameter (d 2 ) of the second circumferential wall on the side of the second chamber satisfying a relationship of d 1 >d 2 , an annular stepped surface being formed between the first circumferential wall and the second circumferential wall;
a portion being provided in which the outer diameter (d 1 ) of the first circumferential wall and an outer diameter (d 3 ) of the cylindrical filter satisfy a relationship of d 1 ≥d 3 ; and
between the cylindrical filter and the inner wall surface of the cylindrical housing opposing the cylindrical filter radially outward, the second cylindrical space which is continuous with the first cylindrical space being secured in a state where the second cylindrical space faces the second communication holes via the cylindrical filter.

3. The gas generator according to claim 1 , wherein the cylindrical filter has uniform inner and outer diameters.

4. The gas generator according to claim 1 , wherein the cylindrical filter has a uniform inner diameter, and the second end surface of the cylindrical filter on the side of the second end of the cylindrical housing has a largest outer diameter,
the outer diameter (d 1 ) of the first circumferential wall, an outer diameter (d 4 ) of the first end surface of the cylindrical filter on the side of the first end of the cylindrical housing, and an outer diameter (d 5 ) of the second end surface of the cylindrical filter satisfy a relationship of d 5 >d 1 ≥d 4 .

5. The gas generator according to claim 1 , wherein the cylindrical filter has a first end surface on the side of the first end of the cylindrical housing, a second end surface on the opposite side in the axial direction to the first end surface and a flange at the second end surface, and an inner diameter from the first end surface to the second end surface is uniform,
the outer diameter (d 1 ) of the first circumferential wall, an outer diameter (d 6 ) of the cylindrical filter on a side of the first end surface, and an outer diameter (d 7 ) of the flange on a side of the second end surface satisfy a relationship of d 7 >d 1 ≥d 6 .

6. The gas generator according to claim 1 , wherein the second circumferential wall of the cylindrical flow channel forming member has a protrusion, which protrudes radially outward, on an outer circumferential surface, and
the cylindrical filter is disposed to enclose the second communication hole between the protrusion and the annular stepped surface.

7. The gas generator according to claim 1 , wherein the second circumferential wall of the second chamber of the cylindrical flow channel forming member has an enlarged diameter portion which expands radially outward, and
the cylindrical filter is disposed to enclose the second commu

Assignees

• Daicel Corp

Inventors

• Fukumoto Kenji
• Kobayashi Tomoharu

Classifications

• B60R2021/26011

  using a filter through which the inflation gas passes · CPC title

• B60R21/217

  Inflation fluid source retainers, e.g. reaction canisters; Connection of bags, covers, diffusers or inflation fluid sources therewith or together · CPC title

• B60R21/2346

  Soft diffusers · CPC title

• B60R21/264 Primary

  using instantaneous generation of gas, e.g. pyrotechnic (B60R21/268 takes precedence) · CPC title

• B60R2021/26029

  Ignitors · CPC title