Gas generator

Patent metadata

Field	Value
Publication number	US-11110885-B2
Application number	US-201816607565-A
Country	US
Kind code	B2
Filing date	Mar 13, 2018
Priority date	Apr 28, 2017
Publication date	Sep 7, 2021
Grant date	Sep 7, 2021

Abstract

A gas generator includes an igniter, a cup-shaped member, and a fixing member. The cup-shaped member accommodating an enhancer agent bursts or melts at the time of activation. The fixing member fixing a filter does not burst and melt even at the time of activation. Ra and Ha satisfy a condition of Ra/Ha 1.00 where Ra represents an inner diameter of a sidewall portion of the cup-shaped member and Ha represents a distance between a top wall portion of the cup-shaped member and the igniter. The sidewall portion includes a first region surrounded by a partition wall portion of the fixing member and a second region not surrounded by the partition wall portion. The partition wall portion has an end portion arranged closer to a top plate portion than the igniter. A gas generating agent is arranged to face the top wall portion, the second region, and the partition wall portion.

First claim

The invention claimed is:

1. A gas generator comprising:
a housing including a cylindrical circumferential wall portion provided with a gas discharge opening and a top plate portion and a bottom plate portion which close one and the other axial ends of the circumferential wall portion, the housing containing a combustion chamber which accommodates a gas generating agent;
an igniter assembled to the bottom plate portion, the igniter including an ignition portion which accommodates an ignition agent ignited at time of activation;
a cup-shaped member containing an enhancer chamber which accommodates an enhancer agent, the cup-shaped member being arranged to protrude toward the combustion chamber such that the enhancer chamber faces the ignition portion, a whole portion of the cup-shaped member which defines the enhancer chamber bursting or melting by combustion of the enhancer agent with activation of the igniter;
a cylindrical filter located in the housing and arranged along an inner circumferential surface of the circumferential wall portion to surround the combustion chamber; and
a fixing member which fixes the filter to the housing, the fixing member not bursting or melting even by combustion of the enhancer agent with activation of the igniter,
the cup-shaped member including a cylindrical sidewall portion which defines the enhancer chamber and a top wall portion which defines the enhancer chamber and closes an axial end portion of the sidewall portion located on a side of the top plate portion,
the fixing member including a base portion applied to the bottom plate portion along an inner bottom surface of the bottom plate portion, an abutment portion which abuts on an inner circumferential surface of the filter close to the bottom plate portion, and a cylindrical partition wall portion erected from the base portion toward the top plate portion,
Ra and Ha satisfying a condition of Ra/Ha≤1.00 where Ra represents an inner diameter of the sidewall portion and Ha represents a distance between the top wall portion and the ignition portion along an axial direction of the circumferential wall portion,
the sidewall portion including a first region located on a side of the bottom plate portion and surrounded by the partition wall portion and a second region located on a side of the top plate portion and not surrounded by the partition wall portion, by arranging the partition wall portion to reach a position in the combustion chamber intermediate along the axial direction of the circumferential wall portion,
an end portion of the partition wall portion on the side of the top plate portion being arranged closer to the top plate portion than the ignition portion in the axial direction of the circumferential wall portion,
the gas generating agent being arranged to face at least the top wall portion, the second region of the sidewall portion, and an outer circumferential surface of the partition wall portion, and wherein
the partition wall portion includes a tapered portion tapered toward the top plate portion.

2. The gas generator according to claim 1 , wherein the Ra and the Ha further satisfy a condition of Ra/Ha≤0.80.

3. The gas generator according to claim 1 , wherein Hb satisfies a condition of Hb≤13.5 [mm] where Hb represents a distance between the end portion of the partition wall portion on the side of the top plate portion and the ignition portion along the axial direction of the circumferential wall portion.

4. The gas generator according to claim 1 , wherein the gas discharge opening is provided at a position closer to the top plate portion than the partition wall portion in the axial direction of the circumferential wall portion.

5. The gas generator according to claim 4 , wherein
the gas discharge opening is provided at a position opposed to the second region of the sidewall portion in a radial direction of the circumferential wall portion.

6. The gas generator according to claim 1 , wherein
the base portion is in a shape of an annular plate, and
the abutment portion is provided to extend from an outer edge of the base portion and the partition wall portion is provided to extend from an inner edge of the base portion.

7. The gas generator according to claim 1 , wherein
the gas generating agent is not arranged in a space between the first region of the sidewall portion and the partition wall portion.

8. A The gas generator according to claim 1 , further comprising:
a holding portion which is provided in the bottom plate portion and holds the igniter,
the bottom plate portion including a protruding cylindrical portion provided to protrude toward the top plate portion,
an opening in which the igniter is inserted and arranged being provided in an axial end portion of the protruding cylindrical portion located on a side of the top plate portion,
the holding portion being made of a resin molded portion at least partly secured to the bottom plate portion by being formed by attaching a fluid resin material to the bottom plate portion so as to reach a part of an outer surface of the bottom plate portion from a part of an inner surface of the bottom plate portion through the opening and solidifying the fluid resin material,
the bottom plate portion in a portion except for the protruding cylindrical portion being in such an inclined shape as being inclined toward the top plate portion, in a direction toward a radially outer side of the circumferential wall portion, and
an inclination angle θ 1 of the bottom plate portion in the portion except for the protruding cylindrical portion satisfying a condition of 0[°]<θ1≤2[°].

Assignees

• Nippon Kayaku Kk

Inventors

• Koyama Hiroaki
• Ueda Shinya
• Ohsugi Satoshi
• Tsuruta Makoto
• Kanaji Motohiro
• Mukunoki Hirotaka

Classifications

• B60R2021/26029

  Ignitors · CPC title

• B60R2021/2648

  comprising a plurality of combustion chambers or sub-chambers · CPC title

• B60R2021/26076

  characterised by casing · CPC title

• B60R21/264 Primary

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

• B60R2021/26011

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