Gas Generator Support Member Prevents Combustion Gas Short-Passing
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Solution Overview
Problem
In airbag gas generators, 'short-passing' occurs when the housing deforms, allowing combustion gas with metal mist to bypass the coolant-filter and directly enter the airbag, due to gaps between the housing and the coolant-filter, which is not effectively prevented by existing support mechanisms.
Innovation Solution
A support member is fixed to the housing and cylindrical filter, with a bottom surface and outer circumferential wall that abuts against the filter's annular end surface and bottom plate, preventing combustion gas from passing through gaps and ensuring filtration, using a combination of press-fitting and holding mechanisms to maintain contact and prevent short-passing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the housing is made deformable to withstand internal pressure, then the housing can accommodate pressure rise during activation, but gaps form between the housing and coolant-filter allowing short-passing of combustion gas
Solution Approach 1:
A support member is introduced as an intermediary component between the housing and the coolant-filter. This support member has a pressing portion that contacts the coolant-filter and a supporting portion that contacts the housing, acting as a mediator to maintain the coolant-filter's position against the housing even when the housing deforms under internal pressure, thereby preventing gap formation and short-passing
2Reliability
If the coolant-filter is press-fitted to the housing to prevent short-passing, then filtration reliability improves, but the filter may detach or fail to maintain contact when the housing deforms
Solution Approach 1:
The support member is designed to dynamically adapt to housing deformation. The pressing portion can move with the coolant-filter while maintaining contact, and the supporting portion accommodates housing shape changes. This dynamic design allows the system to maintain filter-housing contact stability even when the housing deforms under internal pressure during activation
3Reliability
If a support member is added to maintain filter contact with the housing, then short-passing is prevented, but the device complexity increases
Solution Approach 1:
The support member is segmented into distinct functional portions: a pressing portion that contacts the coolant-filter and a supporting portion that contacts the housing. This segmentation allows each portion to be optimized for its specific function while keeping the overall structure simple and easy to manufacture, preventing short-passing without excessive complexity
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 support member effectively prevents short-passing by maintaining contact between the filter and housing, ensuring combustion gas passes through the filter and enhancing the filtration process without hindering gas flow, thus ensuring reliable operation of the gas generator in airbag systems.
Implementation Method 1
The mist contained in the combustion gas is filtered by a coolant-filter disposed in a housing of the gas generator
Implementation Method 2
a support member for the cylindrical filter being disposed on a bottom surface of the closure shell... part of the outer circumferential wall of the support member being held from both sides in a thickness direction between the first holder and the cylindrical filter
Implementation Method 3
When an igniter of the gas generator is activated to burn the gas generating agent
Data Source
AI summary
The present invention provides a gas generator in which short-passing of combustion gas is prevented.A cylindrical filter 30 including a first annular end surface 32 abutted against a top plate 12 and a second annular end surface 33 abutted against a bottom plate 21 is disposed inside a housing 10. A corner portion 75 formed by a bottom surface 71 and an outer circumferential wall 74 of a support member 70 is abutted against an abutting portion between the second annular end surface 33 and the bottom plate 21 to prevent the short-passing of the combustion gas from this portion.