Igniter Assembly Partition Wall for Moisture-Tight Gas Generators
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Solution Overview
Problem
Existing igniter assemblies face challenges in ensuring airtightness due to complex assembly processes and potential impairment from resin shrinkage, which can lead to moisture ingress and compromised sealing.
Innovation Solution
An igniter assembly design featuring a partition wall made of moisture-impermeable material, welded all around to the igniter holding portion or case, separates the combustion chamber and prevents moisture ingress, with a thinner thickness to facilitate rupture during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a resin fixing member is used to integrate the igniter and collar, then assembly work is simplified, but airtightness is impaired due to resin shrinkage during curing
Solution Approach 1:
The partition wall is separated into a distinct component from both the igniter holding portion and the case, allowing it to be welded to both parts independently. This segmentation enables the partition wall to provide reliable airtightness through welding while the resin fixing member handles the igniter integration, resolving the contradiction between simplified assembly and maintained airtightness.
Solution Approach 2:
The solution combines different materials and joining methods: the resin fixing member provides simplified assembly for the igniter, while the partition wall made of moisture-impermeable material with all-around welding provides reliable airtightness. This composite approach uses the strengths of each material for its appropriate function.
2Reliability
If the partition wall is made thicker to ensure moisture impermeability, then airtightness is improved, but the partition wall may not rupture appropriately during igniter operation
Solution Approach 1:
The partition wall has non-uniform thickness distribution, being thinner at the bottom portion where rupture is needed during operation and thicker at the sidewall portions where moisture impermeability is critical. This local quality variation allows the partition wall to simultaneously achieve reliable moisture blocking and appropriate rupture behavior during igniter operation.
3Reliability
If additional sealing members are added to ensure airtightness, then moisture prevention is improved, but assembly complexity increases
Solution Approach 1:
The solution extracts the sealing function from separate sealing members and integrates it into the partition wall itself through all-around welding to both the igniter holding portion and the case. This creates a built-in sealing structure that prevents moisture ingress without requiring additional sealing components, thus maintaining reliability while avoiding increased assembly complexity.
4Reliability
If the partition wall is welded all around to ensure airtightness, then moisture ingress is prevented, but manufacturing complexity increases
Solution Approach 1:
The partition wall is designed with protrusions and recesses that enable preliminary positioning and alignment before welding. This preliminary action facilitates the all-around welding process by ensuring proper fit and orientation, making the manufacturing work more manageable while achieving reliable airtightness.
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
Ensures airtightness of the combustion chamber by preventing moisture entry and allowing easy assembly through all-around welding, reducing the need for additional sealing members.
Implementation Method 1
the partition wall having moisture impermeability
Implementation Method 2
the partition wall is fixed in a state of being in contact with the case and is welded all around to at least one of the igniter holding portion or the case
Data Source
AI summary
An igniter assembly includes: an ignition device including: an igniter including an ignition portion airtightly accommodating an ignition charge and a conductive portion that supplies an ignition current for igniting the ignition charge, an igniter holding portion having a tubular shape and holding the igniter, and a fixing member made of a resin, interposed between the igniter and the igniter holding portion, and fixing the igniter to the igniter holding portion; a case having a bottomed tubular shape and accommodating a first gas generating agent and the ignition portion of the igniter, and a partition wall partitioning an inside of the case into a space in which the igniter and the fixing member are disposed and a space in which the first gas generating agent is accommodated, the partition wall having moisture impermeability. The partition wall is fixed and in contact with the case.