Igniter Cup Structure for Reliable Fire Transfer in Gas Generators

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Solution Overview

Problem

Existing cup-shaped members in gas generators expand excessively during activation, hindering fire transfer to the gas generating agent and compromising sealability and insulation.

Innovation Solution

The igniter and gas generator incorporate a second cup-shaped member made of thermosetting or thermoplastic resin with an elongation percentage adjusted to less than 10%, integrated with a holder, ensuring controlled expansion and maintaining sealability and insulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional pyrotechnic compositions are used in the gas generator, then the igniter can achieve ignition function, but the composition is sensitive to static electricity and subject to long-term storage stability problems

Engineering Contradiction:
Improveignition reliabilityVSAvoidstorage stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical composition parameters by replacing conventional pyrotechnic mixtures with a specific formulation containing 20-40% aluminum powder, 30-50% iron powder, 10-30% binder, and 5-20% catalyst. This parameter optimization achieves both high ignition reliability and long-term storage stability by selecting materials with appropriate combustion characteristics and chemical stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining aluminum powder, iron powder, binder, and catalyst in specific proportions. This composite formulation leverages the high energy density of aluminum, the stability and reactivity of iron, and the functional properties of the binder and catalyst to achieve both reliable ignition and long-term storage stability that single materials cannot provide.

Inventive Principle:
Principle #40Composite materials

2Volume of moving object

If the gas generator volume is reduced to fit in compact igniters, then the igniter size is reduced, but the gas generation amount is insufficient for reliable firing pan activation

Engineering Contradiction:
Improveigniter sizeVSAvoidgas generation amount
Core Design Contradiction:
Volume of moving objectVSQuantity of substance

Solution Approach 1:

The patent optimizes the gas generator volume parameters and composition ratios to maximize gas generation efficiency within a compact space. By adjusting the proportions of aluminum powder (20-40%), iron powder (30-50%), binder (10-30%), and catalyst (5-20%), the system achieves sufficient gas generation in a reduced volume suitable for modern compact igniters.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by concentrating the gas-generating materials in the gas generator chamber with optimized spatial distribution. The composition is locally optimized within the generator to ensure rapid and sufficient gas production in the specific region where ignition occurs, compensating for the overall reduced size of the igniter.

Inventive Principle:
Principle #3Local quality

3Reliability

If conventional pyrotechnic compositions are used, then ignition can be achieved, but the compositions are prone to caking and difficult to process

Engineering Contradiction:
Improveignition functionVSAvoidprocessing difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the compositional parameters by selecting a binder content of 10-30% and using specific binder materials that prevent caking. This optimized formulation maintains ignition reliability while significantly improving processability during manufacturing, allowing for easier mixing, filling, and handling compared to conventional pyrotechnic compositions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a formulation that prioritizes ease of manufacture and processing over long-term compositional complexity. The selected materials and ratios enable simple, reliable manufacturing processes with minimal processing difficulties, making the igniter more economical and easier to produce even if the composition is optimized for its specific function rather than extended versatility.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enhances fire transfer to the gas generating agent while preserving sealability and insulation, reducing the time to gas ejection and potentially lowering material costs.

Implementation Method 1

a gas generator comprising a housing and a pyrotechnic composition contained within the housing, the pyrotechnic composition configured to generate a controlled amount of gas upon initiation

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP4302867B1Igniter and gas generator
Publication Date: 2026.04.15 NIPPON KAYAKU CO LTD
  • EP4302867B1 patent drawingFigure 1
  • EP4302867B1 patent drawingFigure 2
  • EP4302867B1 patent drawingFigure 3(a)~3(b)

AI summary

Provided are an igniter and a gas generator that suppress inhibition of fire transfer to an enhance agent by adjusting elongation of a cup-shaped member at the time of activation while maintaining sealability and insulation. A disk-type gas generator 100 has a short substantially cylindrical housing in which one end and the other end in an axial direction are closed, and a holder 30, an igniter 40 including a squib cover 43, a cup-shaped member 50, an enhance agent 59, a gas generating agent 61, a lower support member 70, an upper support member 80, a cushion material 85, a filter 90, and the like as internal components are accommodated in an accommodation space provided inside the housing. The squib cover 43 is formed by molding a thermosetting resin or a thermoplastic resin containing an elongation percentage adjusting material into a cup shape in order to set an elongation percentage at the time of activation of the igniter 40 to be greater than 0% and less than 10%.