Gas Generator Closing Member Segmentation for Seal Integrity
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Solution Overview
Problem
The existing pyrotechnic gas generators for airbag systems face issues with maintaining designed actuation performance due to deformation of the flanged cap during ignition, leading to gaps and short-passing of combustion products, which affects ignition efficiency and increases processing costs.
Innovation Solution
A gas generator design featuring a cylindrical housing with a transfer charge chamber housing and a closing member, where the transfer charge chamber housing is press-fitted with an annular wall surface that abuts against the closing member, enhancing fixation strength and sealability, and using a supporting member like a tubular filter or retainer to secure the flange portion, reducing the need for complex processing and maintaining ignition performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flanged cap is used to close the combustion chamber, then the gas generator can be assembled with standard components, but the flanged cap deforms during ignition causing gaps and short-passing of combustion products
Solution Approach 1:
The closing member is divided into a disk-shaped main body portion and a separate annular projection portion. The annular projection portion is fitted into an annular groove formed by the tubular housing and closing member, creating a segmented structure that prevents deformation during ignition while maintaining ease of assembly with standard components.
Solution Approach 2:
The annular projection portion of the closing member is nested within the annular groove formed by the tubular housing and closing member. This nested structure provides structural support during ignition, preventing the flanged cap from deforming and causing gaps that would lead to short-passing of combustion products.
2Ease of manufacture
If the transfer charge chamber housing is loosely attached to the closing member, then assembly is simpler, but fixation strength is insufficient to maintain sealability during combustion
Solution Approach 1:
The transfer charge chamber housing is attached to the closing member with a press-fit connection that provides dynamic fixation. The annular wall surface of the transfer charge chamber housing fits into the annular groove, creating a connection that maintains sufficient fixation strength during combustion while allowing for thermal expansion and pressure changes.
Solution Approach 2:
The annular groove acts as an intermediary structure between the transfer charge chamber housing and the closing member. This intermediate feature provides both the necessary fixation strength to maintain sealability during combustion and the structural flexibility to accommodate thermal and pressure changes without compromising the connection.
3Manufacturing precision
If complex processing is used to ensure proper fitting and sealing, then assembly precision is improved, but processing costs increase
Solution Approach 1:
The annular groove is pre-formed by the tubular housing and closing member before the transfer charge chamber housing is attached. This preliminary action ensures proper fitting and sealing positions are established in advance, maintaining manufacturing precision while avoiding the need for complex post-assembly processing operations.
Solution Approach 2:
The annular groove structure is designed to self-align and self-seal the transfer charge chamber housing to the closing member. The geometric constraints of the groove and projection portions automatically ensure proper positioning and sealing contact, eliminating the need for complex external processing or adjustment 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 enhanced sealability and fixation strength prevent short-passing of combustion products, maintaining designed actuation performance and reducing processing costs by simplifying the assembly process.
Implementation Method 1
an igniter 25 attached to the second closing member 30, a transfer charge chamber housing 40 surrounding the igniter 25, the inside of the transfer charge chamber housing 40 serving as a transfer charge chamber 45 charged with a transfer charge 46
Implementation Method 2
the bottom surface 41 formed with a plurality of flame-transferring holes 41a, the combustion chamber 70 charged with a gas generating agent 71
Data Source
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AI summary
The present application provides a gas generator including: a cylindrical housing with a gas discharge port, one end of the tubular housing being closed by a closing member including a disk-shaped main body portion, an annular projection portion and the peripheral surface of the annular projection portion, a transfer charge chamber housing defining a transfer charge chamber charged with a transfer charge and being attached to the closing member, the transfer charge chamber housing having a cup-like shape including a flame-transferring hole at a bottom surface, a flange portion and a annular wall surface extending in the axial direction of the housing from the flange portion, being mounted such that the annular wall surface thereof is fitted into an annular groove, and being fixed by the flange portion pressed in the axial direction by a supporting member and a sealing member disposed in a remaining space of the annular groove and sealing between the tubular housing and the closing member.