Gas Generator Resin Molding Segmentation for Impact and Thermal Control
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Solution Overview
Problem
Gas generators with a thick resin molding covering the entire outer circumferential surface of the ignition portion face issues with crack generation due to impact during activation, leading to unintended burning states and reduced gas output, while partial coverage results in inefficient thermal particle guidance and low gas output.
Innovation Solution
A gas generator design featuring a housing with a cylindrical igniter and a resin molding that includes an annular wall portion surrounding the ignition portion, with a lower cover portion covering the contact area and an upper cover portion covering the non-contact area, providing directivity to thermal particles and preventing crack formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the entire outer circumferential surface of the ignition portion is covered with a thick resin molding, then directivity of thermal particles is improved, but crack generation occurs due to impact during activation
Solution Approach 1:
The resin molding is segmented into two distinct portions: a first resin molding covering part of the outer circumferential surface of the ignition portion, and a second resin molding covering the terminal pin. This segmentation allows the first resin molding to provide thermal particle directivity while the second resin molding protects the terminal pin from impact, preventing crack generation and ensuring reliability.
2Reliability
If only part of the outer circumferential surface of the ignition portion is covered with resin molding, then crack generation is suppressed, but thermal particle directivity is reduced
Solution Approach 1:
The resin molding is segmented into two distinct portions: a first resin molding covering part of the outer circumferential surface of the ignition portion, and a second resin molding covering the terminal pin. This segmentation allows the first resin molding to provide thermal particle directivity while the second resin molding protects the terminal pin from impact, preventing crack generation and ensuring reliability.
3Reliability
If the terminal pin is exposed without resin molding coverage, then impact resistance is improved, but thermal particle guidance efficiency decreases
Solution Approach 1:
The resin molding is segmented into two distinct portions: a first resin molding covering part of the outer circumferential surface of the ignition portion, and a second resin molding covering the terminal pin. This segmentation allows the first resin molding to provide thermal particle directivity while the second resin molding protects the terminal pin from impact, preventing crack generation and ensuring reliability.
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 design achieves high gas output early in the activation stage while preventing operational failures by directing thermal particles effectively and absorbing impact, ensuring the resin molding's integrity.
Implementation Method 1
an igniter being ignited in response to power feed through a control unit at the time of collision of a vehicle to thereby burn a gas generating agent with flame caused by the igniter
Data Source
AI summary
A gas generator includes a cylindrical housing including a top plate portion and a bottom plate portion, an igniter including an ignition portion charged with an ignition agent, and a fixing portion which is formed from a resin molding and fixes the igniter to the bottom plate portion. The fixing portion includes an annular wall portion surrounding an outer circumferential surface of the ignition portion. The annular wall portion has a lower cover portion provided as being continuous in a circumferential direction on a side of the bottom plate portion so as to cover the outer circumferential surface of the ignition portion as being secured to the outer circumferential surface of the ignition portion and an upper enclosing portion provided on a side of the top plate portion at a distance from the outer circumferential surface of the ignition portion.