One-Piece Woven Airbag Limiting Threads for Stepwise Inflation
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Solution Overview
Problem
Existing airbag designs with rebound straps and X-tethers face issues such as sudden inflation leading to high tensile forces, potential detachment of fabric from the laminate, leak points, and inability to achieve stepwise inflation in predefined regions, resulting in disruptive deployment and potential airbag failure.
Innovation Solution
A one-piece woven airbag with upper and lower fabrics joined by a single-ply seam and tether threads, featuring upper and lower limiting threads that float between the fabrics and are attached at specific points, allowing controlled release of airbag volume and targeted inflation based on pressure and time, preventing fabric detachment and leak points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rebound straps are used to define inflation stages, then stepwise inflation is achieved, but the construction becomes complex with multiple individual parts sewn together
Solution Approach 1:
The patent merges the rebound strap functionality directly into the airbag fabric by weaving tether threads through the fabric layers during the weaving process. This integration eliminates the need for separate rebound strap components and their associated sewing operations, achieving stepwise inflation through the limiting threads while maintaining a unified single-ply construction.
Solution Approach 2:
The airbag fabric serves multiple functions simultaneously: it provides structural containment, defines inflation stages through integrated limiting threads, and eliminates the need for separate rebound straps. The weaving process itself creates both the fabric structure and the tether thread attachment points, demonstrating multi-functionality that reduces overall system complexity.
2Productivity
If X-tethers are used for rebound, then inflation stages are defined, but sudden filling exerts high tensile forces causing fabric detachment and leak points
Solution Approach 1:
The limiting threads are pre-integrated into the fabric structure during the weaving process, creating predetermined attachment points and distribution paths for tensile forces. This preliminary integration ensures that when inflation occurs, the forces are distributed along the woven path rather than concentrating at discrete attachment points, preventing fabric detachment and leak points.
Solution Approach 2:
The patent changes the physical state and distribution of force transmission by transitioning from discrete X-tether attachment points to a continuous woven structure. The limiting threads are distributed throughout the fabric layers, transforming the force distribution parameter from concentrated to dispersed, thereby reducing peak tensile stresses that cause fabric detachment.
3Volume of moving object
If the entire airbag is inflated to maximum volume, then full deployment is achieved, but stepwise inflation in predefined regions becomes impossible or very difficult
Solution Approach 1:
The airbag is segmented into multiple inflation stages through the integration of limiting threads at different positions within the fabric structure. These limiting threads create predefined regions that inflate at different pressures, allowing the airbag to progress from partial to full volume in controlled steps rather than as a single simultaneous expansion event.
Data Source
AI summary
The invention relates to a one-piece woven airbag, in particular for vehicle restraint systems, with an upper fabric and a lower fabric which are joined together in a single-ply seam area forming the border of the airbag, with tether threads which are woven partially into the upper fabric and partially into the lower fabric and float there between over a defined length, which is characterized by upper limiting threads which are woven into the upper fabric and/or lower limiting threads which are woven into the lower fabric, the limiting threads between upper fabric and lower fabric floating over a defined number of floating tether threads and being attached to attachment points of their fabric layer.