Glass-Ceramic Feedthrough Surface for Bubble-Free Igniter Sealing
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Solution Overview
Problem
Existing metal fixing material feedthroughs for igniters in airbags and seat belt pretensioners require surface grinding to achieve a smooth surface, which can lead to damage and mechanical stress on the bridge wire due to grinding marks and potential bubble formation, affecting long-term functionality and reliability.
Innovation Solution
A metal fixing material feedthrough with a freely fused glassy or glass-ceramic surface that is melted free during manufacturing, eliminating the need for grinding, and featuring a smooth, bubble-free surface with a trench design to prevent mechanical stress and film deposition, ensuring a hermetic seal and reduced roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If surface grinding is applied to the fixing material, then a smooth surface is achieved, but grinding marks and mechanical stress are introduced that can damage the bridge wire
Solution Approach 1:
Instead of grinding the surface to achieve smoothness, the patent inverts the approach by melting the fixing material surface to create a naturally smooth, bubble-free finish. This eliminates the harmful grinding marks while achieving the desired surface quality, thereby protecting the bridge wire from mechanical stress and damage.
Solution Approach 2:
The patent changes the physical state of the fixing material from solid to liquid and back to solid through controlled melting and cooling. This phase transition allows the material to form a smooth surface naturally, avoiding the mechanical stress introduced by grinding while maintaining the required surface smoothness for bridge wire contact.
2Manufacturing precision
If grinding is used to smooth the surface, then contact quality is improved, but bubbles may form and mechanical stress increases
Solution Approach 1:
The patent utilizes phase transitions of the fixing material (solid-liquid-solid) through controlled melting and cooling. During melting, bubbles rise to the surface and can be removed, and upon cooling, the material solidifies into a smooth, bubble-free surface that eliminates mechanical stress while maintaining high contact quality.
Solution Approach 2:
The patent converts the potential harm of bubble formation during melting into a benefit by allowing bubbles to rise to the surface during the liquid phase where they can be removed, resulting in a bubble-free final product. The melting process itself, which could introduce defects, becomes the mechanism for eliminating them.
3Reliability
If a smooth surface is achieved through grinding, then electrical contact is improved, but the process complexity and time increase
Solution Approach 1:
The patent merges the surface smoothing function into the melting and cooling process itself, eliminating the need for a separate grinding operation. The melting process simultaneously removes bubbles and creates a smooth surface, while the cooling process solidifies the material, combining multiple functions into one integrated process step.
Solution Approach 2:
The fixing material performs self-service by naturally forming a smooth surface through its own melting and cooling process. The material's phase transition automatically creates the desired surface quality without requiring external mechanical intervention like grinding, thereby simplifying the manufacturing process and improving productivity.
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 hermetically sealed, mechanically stable connection with reduced risk of damage to the bridge wire, enhancing the longevity and reliability of igniters by minimizing mechanical stress and preventing film deposition, thus ensuring consistent performance over time.
Implementation Method 1
the surface of the glassy or glass-ceramic fixing material is a freely fused surface
Implementation Method 2
freely fused surface, which is particularly advantageously free of exposed bubbles
Implementation Method 3
at least one metal pin is fused into an electrically insulating glassy or glass-ceramic fixing material
Data Source
Figure 1
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AI summary
The invention relates to a metal-fixing material feedthrough, particularly for airbag and/or seatbelt pretensioner igniters, comprising at least one metal pin (5) fused into a through-opening (4) of a base body (1) in a glassy or glass-ceramic fixing material (10). The surface (110) of the glassy or glass-ceramic fixing material (10) is a free-melting surface that lies in a plane with the end face (50) of the at least one metal pin (5). The free-melting surface, particularly in the area of the ignition wire (9), has no exposed bubbles.