Resin Gas Generator Rupture Structure for Fragment Containment
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Solution Overview
Problem
Resin cases in gas generators have a lower breaking strength than metal, leading to a high likelihood of fragment scattering during rupture.
Innovation Solution
A gas generator design featuring a resin case with a fragile part and an annular inclination portion, where the fragile part is thicker than its periphery, and an annular inclination portion is formed inside the case, concentrating stress and controlling the rupture direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a resin case is used to accommodate the gas generating agent, then the weight and manufacturing ease are improved, but the breaking strength is reduced leading to fragment scattering during rupture
Solution Approach 1:
The closing end portion is segmented into a fragile part (thinner section) and a periphery part (thicker section). This segmentation allows the fragile part to rupture cleanly under pressure while the thicker periphery maintains structural integrity and prevents fragment scattering, resolving the contradiction between using lightweight resin and achieving sufficient strength.
Solution Approach 2:
The case employs local quality variation by making the fragile part thinner than the periphery. This localized thinning creates a controlled weak point that ruptures predictably, while the surrounding thicker material provides structural support and prevents uncontrolled fragment scattering, thus maintaining both light weight and adequate strength where needed.
2Weight of moving object
If the case is made thinner to reduce weight, then the weight is reduced, but the likelihood of uncontrolled fragment scattering increases
Solution Approach 1:
The closing end is divided into a fragile part and a periphery part with different thicknesses. The fragile part is designed to be thinner for controlled rupture, while the periphery remains thicker to contain fragments, thus reducing weight without increasing harmful fragment scattering.
Solution Approach 2:
The annular inclination portion acts as an intermediary structure between the fragile part and the periphery. It gradually transitions the thickness from the thin fragile part to the thicker periphery, providing structural support that prevents uncontrolled fragment scattering while allowing the fragile part to rupture cleanly.
3Reliability
If a fragile part is created for controlled rupture, then the rupture control is improved, but the structural strength of the closing end is reduced
Solution Approach 1:
The closing end is segmented into a fragile part for controlled rupture and a periphery part for structural support. This segmentation allows the fragile part to open reliably under combustion pressure while the stronger periphery maintains overall structural integrity.
Solution Approach 2:
The closing end employs asymmetric thickness distribution, with the fragile part being thinner than the periphery. This asymmetry creates a predetermined weak point for reliable rupture control while the thicker periphery compensates for the reduced strength in the fragile part, maintaining overall structural strength.
4Strength
If the periphery is made thicker to prevent fragment scattering, then the structural integrity is improved, but the weight increases
Solution Approach 1:
The case applies local quality by making only the periphery thicker while keeping the fragile part thin. This localized thickening provides structural integrity and prevents fragment scattering only where needed, without unnecessarily increasing the weight of the entire case.
Solution Approach 2:
The closing end is segmented into a thin fragile part and a thicker periphery part. This segmentation allows the periphery to be made thicker for structural integrity and fragment containment, while the fragile part remains thin to minimize weight, achieving the balance between strength and weight.
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
Suppresses case scattering by ensuring the fragile part ruptures cleanly, preventing fragments from entering the attachment target and maintaining efficient gas discharge.
Implementation Method 1
a case having a bottomed tubular shape and being configured to accommodate a gas generating agent which combusts by actuation of the ignition device
Implementation Method 2
the fragile part is configured to open by a combustion product generated by the gas generating agent
Data Source
AI summary
A gas generator includes an ignition device including an igniter, an igniter holding portion, and a fixing portion made of resin and a case having a bottomed tubular shape and being configured to accommodate a gas generating agent which combusts by actuation of the ignition device, the case made of resin and including a side wall portion with a base end side being connected to the fixing portion, and a closing end portion configured to close a tip end side. The closing end portion includes a fragile part configured to open by a combustion product generated by the gas generating agent, a periphery of the fragile part is greater in thickness than the fragile part, and an annular inclination portion is formed inside the case from a predetermined position of the side wall portion to the fragile part.