Gas Generator Housing Sealing with Caulked Aluminum Plug

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Solution Overview

Problem

The increasing number of airbag systems in automobiles leads to increased weight and reduced interior space, necessitating a gas generator that is reduced in weight and size while maintaining sufficient strength as a pressure vessel.

Innovation Solution

A gas generator with a tubular housing and a plug sealed by a multi-directional caulking groove, where the housing is made of steel and the plug is formed of a lower hardness and specific gravity metal, such as aluminum or its alloys, with a caulking groove configuration that enhances the plug's latching and reduces its size and weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the number of airbag systems is increased to improve passenger safety, then the safety performance is improved, but the vehicle weight increases and fuel efficiency decreases

Engineering Contradiction:
Improvepassenger safetyVSAvoidvehicle weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent changes the material parameters of the gas generator by using aluminum or aluminum alloy for the housing instead of traditional steel. Aluminum has lower density (approximately 2.7 g/cm³) compared to steel (approximately 7.8 g/cm³), which directly reduces the weight of the gas generator while maintaining its structural integrity and pressure-containing capability. This material substitution enables weight reduction of the gas generator itself, contributing to overall vehicle weight reduction when multiple airbags are installed.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the number of airbag systems is increased to improve passenger safety, then the safety performance is improved, but the interior space of the automobile is reduced

Engineering Contradiction:
Improvepassenger safetyVSAvoidinterior space
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent employs aluminum or aluminum alloy materials for the gas generator housing, which have lower density and enable design of a more compact structure. The reduced material density allows for optimization of the gas generator's volume and shape, reducing its overall size. This compact design minimizes the space occupied by each airbag system, thereby preserving more interior space in the automobile when multiple airbags are installed.

Inventive Principle:
Principle #35Parameter changes

3Strength

If a steel plug is used to seal the housing opening to ensure sufficient strength, then the pressure vessel strength is maintained, but the weight and size of the gas generator increase

Engineering Contradiction:
Improvepressure vessel strengthVSAvoidgas generator weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent substitutes the traditional steel plug with a plug made of aluminum or aluminum alloy. Although aluminum has lower strength than steel, the plug's structural design is optimized to compensate for this difference. The aluminum plug achieves sufficient sealing strength and pressure resistance through appropriate geometric design and thickness optimization, while its lower density (approximately one-third that of steel) dramatically reduces the overall weight of the gas generator.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite construction by combining aluminum housing with aluminum plug, creating a homogeneous lightweight structure. This composite approach allows both components to be made from the same or similar materials, simplifying manufacturing processes such as joining and sealing, while achieving consistent weight reduction throughout the pressure vessel structure. The composite aluminum structure maintains sufficient strength through optimized design rather than relying on high-strength steel.

Inventive Principle:
Principle #40Composite materials

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

The configuration ensures the gas generator's strength as a pressure vessel, allowing it to be reduced in weight and size while maintaining structural integrity, and prevents the plug from being pulled out under internal pressure.

Implementation Method 1

an end portion on the opening side is reduced in diameter and caulked by multi-directional caulking in a caulking groove of the plug, to thereby seal the opening

Methodology Applied
Scientific EffectCaulking:

Implementation Method 2

a gas generator capable of generating a high-temperature, high-pressure gas through combustion of a gas generating agent filled in the gas generator

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP2684747B1Gas Generator
Publication Date: 2016.05.04 NIPPON KAYAKU CO LTD
  • EP2684747B1 patent drawingFigure 1(a)~1(b)
  • EP2684747B1 patent drawingFigure 2(a)~2(b)
  • EP2684747B1 patent drawingFigure 3~4

AI summary

Provided is a gas generator which is reduced in weight and size while maintaining a sufficient strength as a pressure vessel. A gas generator (1) includes a housing (4) in a tubular shape having an opening (10) on at least one end thereof and a plug (12) inserted in the opening (10), so that an end portion (11) on the opening side is reduced in diameter and caulked in a caulking groove (13) of the plug (12), to thereby seal the opening (10), in which: the caulking groove (13) is a streak groove that extends along the periphery of the plug (12) and is rectangular in section; and the caulking groove (13) has at least one of side walls forming the calking groove (13), the one side wall being closer to the center of the housing, which is orthogonal or sloped to the opening side, with respect to the axis of the housing (4).