Gas Generator Igniter Sealing via Stepped Housing and Inclined Collar
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Solution Overview
Problem
Existing gas generator designs with cylindrical housings face challenges in sealing and fixing the igniter without increasing the number of parts or manufacturing steps, particularly due to the use of plastic adapter sleeves which can lead to insufficient fixing and difficulty in strong crimping, and limitations in arranging gas generating agents close to the igniter.
Innovation Solution
A closing structure with an igniter that utilizes a stepped surface on the cylindrical housing and an igniter collar with an annular plate portion and inclined surfaces to achieve high sealing and fixing properties by swaging the distal end circumferential wall, eliminating the need for additional parts and steps, and ensuring the igniter remains securely attached without rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a plastic adapter sleeve is used to fix the igniter, then the igniter can be attached to the cylindrical housing, but the fixing strength is insufficient and strong crimping becomes difficult
Solution Approach 1:
The igniter collar is merged with the igniter main body to form an integrated component. The collar portion of the igniter collar directly contacts and is crimped to the cylindrical housing, eliminating the need for separate adapter sleeves and achieving strong fixing through direct metal-to-metal crimping
Solution Approach 2:
The igniter collar is made of metal material with different properties from the plastic adapter sleeve, providing superior strength and crimpability. The metal collar can withstand strong crimping forces while maintaining fixing strength, resolving the contradiction between fixing strength and ease of manufacture
2Reliability
If the igniter collar is made of metal material, then the sealing and fixing properties are improved, but the weight increases
Solution Approach 1:
Only the collar portion that requires sealing and fixing strength is made of metal material, while other parts of the igniter can use lighter materials. This localized use of metal provides the necessary reliability for sealing and fixing without unnecessarily increasing the overall weight of the igniter assembly
3Reliability
If the inclined surface is formed in multiple locations on the second annular circumferential edge, then the sealing property is improved, but the manufacturing complexity increases
Solution Approach 1:
The inclined surfaces are formed at specific asymmetric locations on the second annular circumferential edge rather than uniformly distributed. This asymmetric arrangement provides effective sealing at critical contact points while keeping the manufacturing process relatively simple through targeted forming operations
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 solution provides a high sealing and fixing property for the igniter, preventing rotation and ensuring the igniter remains attached during pressure increases, facilitating easy assembly and maintaining the integrity of the gas generator's operation.
Implementation Method 1
the annular circumferential surface and the second annular circumferential edge which is provided with the inclined surface, of the igniter collar, being abutted against the distal end circumferential wall
Data Source
AI summary
The present invention provides a closing structure which closes, with an igniter, an opening of a cylindrical housing used in a gas generator, the cylindrical housing provided with a stepped surface formed on an inner side of a circumferential wall on the side of the opening, and a distal end circumferential wall extending from the stepped surface to the opening, the igniter having an igniter main body, and an igniter collar surrounding part of the igniter main body and having an annular plate portion with a maximum outer diameter and a circumferential wall excluding the annular plate portion, the annular plate portion including, a first annular surface facing the ignition portion of the igniter main body, a second annular surface facing the electroconductive pin of the igniter main body, and an annular circumferential surface between the first annular surface and the second annular surface, a first annular circumferential edge at the boundary between the first annular surface and the annular circumferential surface, and a second annular circumferential edge at the boundary between the second annular surface and the annular circumferential surface, and the second annular circumferential edge provided with an inclined surface in three or more locations, and the first annular surface of the igniter collar being abutted against the stepped surface of the cylindrical housing, and the annular circumferential surface and the second annular circumferential edge of the igniter collar being abutted against the distal end circumferential wall.