Airbag Module Zigzag Folding with Central Gas Generator
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Solution Overview
Problem
The existing methods for folding gas bags, particularly steering wheel airbags, are inefficient in terms of space usage and reproducibility, leading to suboptimal unfolding properties and complexity in the folding process.
Innovation Solution
A method involving zigzag folding with a gas generator placed in the middle third of the gas bag, where the end sections are folded outward and around the generator, creating an elongated accordion-like structure that maximizes space usage and facilitates rapid deployment by minimizing resistance during gas release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the gas bag is folded using conventional zigzag methods with ends folded inward, then the folding process is relatively simple, but the space efficiency and unfolding properties are suboptimal
Solution Approach 1:
The gas bag is divided into multiple sections: a middle third containing the gas generator and two end thirds that are folded in opposite directions. This segmentation allows each section to serve a specific function - the middle section provides structural support while the end sections maximize space utilization by wrapping around the gas generator in opposite directions
Solution Approach 2:
The folding method transitions from conventional two-dimensional zigzag folding to three-dimensional wrapping around the gas generator. The end sections are folded around the outer circumference of the gas generator, creating a compact three-dimensional package that efficiently utilizes available space while maintaining good unfolding properties
2Volume of moving object
If the gas bag is folded multiple times to maximize space usage, then space efficiency improves, but the unfolding properties deteriorate due to increased resistance
Solution Approach 1:
The gas bag folding is segmented into distinct zones: the middle third remains relatively open to provide a low-resistance path for gas flow during deployment, while the end thirds are folded around the gas generator to maximize space efficiency. This segmentation ensures that space optimization does not compromise deployment speed
Solution Approach 2:
Different regions of the gas bag are folded with different characteristics - the middle section maintains larger openings and fewer folds to facilitate rapid gas expansion, while the end sections are tightly folded around the gas generator to minimize package size. Each region's folding pattern is optimized for its specific functional requirements
3Stability of the object's composition
If the gas generator is positioned at the center of the folded package, then symmetry is achieved, but space efficiency along the outer circumference is reduced
Solution Approach 1:
The gas generator is positioned in the middle third of the gas bag, and the end sections are folded around the outer circumference of the gas generator in opposite directions. This three-dimensional arrangement maximizes space efficiency along the outer circumference while maintaining structural stability through the central positioning of the gas generator
4Ease of manufacture
If conventional folding methods are used, then the folding process is economically viable, but the reproducibility and tolerance control are insufficient
Solution Approach 1:
The gas bag is pre-folded into a zigzag configuration before the gas generator is inserted. This preliminary folding action creates a structured framework that guides the subsequent folding steps, ensuring consistent and reproducible results. The pre-defined fold lines and patterns make the process easier to control and maintain tight tolerances
Solution Approach 2:
The folding process is divided into discrete, manageable steps: initial zigzag folding, gas generator insertion, and final wrapping of end sections. This segmentation of the manufacturing process improves reproducibility by making each step controllable and measurable, while maintaining economic viability through efficient use of standard manufacturing techniques
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
This method allows for a more space-efficient and reproducible folding process, enabling rapid and effective airbag deployment, especially in compact environments like steering wheel modules, and potentially eliminates the need for 2-stage pyrotechnic gas generators in certain situations.
Implementation Method 1
The gas bag package itself can be folded more reproducibly and in a more space-saving manner if the gas bag is thermally heated and/or pressed to create the zigzag fold. When the gas bag is heated and pressed, a so-called heat-set pre-folding occurs
Data Source
Figure 1~4
Figure 5~6
AI summary
According to the disclosed method for folding an airbag (10), the airbag (10) is first folded in a zigzag manner, and a gas generator (14) and/or an airbag-retaining metal sheet is/are placed in the airbag (10), whereupon end portions of the airbag extend around the outer circumference of the gas generator (14) and/or of the airbag-retaining metal sheet, towards each other in opposite directions up to a folding zone (26), from where the end portions are folded over outwards and are laid down in the opposite direction. Also disclosed is a corresponding airbag module.