Airbag Tether Detachment for Controlled Deployment
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Solution Overview
Problem
Front airbags with large filling volumes and irregular three-dimensional configurations often hinder smooth deployment into vehicle interiors due to their size and shape, making it difficult to position them effectively for optimal protection.
Innovation Solution
A vehicle occupant restraint system with an airbag module that includes a tether mechanism, allowing the airbag to deploy from above along the windshield, where the tether detaches at a predetermined tensile force, influencing deployment behavior and filling order, and features a neck section that is narrower and shorter than the main restraint part to save material and space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the airbag has a large filling volume and irregular three-dimensional configuration, then the airbag provides effective protection coverage, but the deployment into the vehicle interior becomes impeded
Solution Approach 1:
The airbag is divided into multiple zones (first zone, second zone, third zone) that inflate in a specific sequence. The first zone acts as a leading section that deploys first to clear the path, followed by the second and third zones. This segmentation allows the large-volume airbag to deploy smoothly by breaking the deployment process into manageable stages, resolving the contradiction between large volume and deployment smoothness.
2Reliability
If the airbag is restrained for several milliseconds after activation, then the deployment behavior can be controlled, but the filling time is extended
Solution Approach 1:
The tether is pre-attached to the first free end of the airbag before deployment. This preliminary arrangement ensures that when the airbag inflates, the tether automatically restrains the first free end in a controlled manner. The restraint is built into the system design, providing reliable deployment control without requiring additional active control mechanisms, and the restraint duration is naturally limited to the time needed for the airbag to reach its deployed position.
3Loss of substance
If the neck is designed narrower and shorter, then material and space are saved, but the connecting function between restraint part and inflator must be maintained
Solution Approach 1:
The neck dimensions (width and length) are optimized to be narrower and shorter than conventional designs. This parameter change reduces material consumption and saves space within the airbag module. The connecting function between the restraint part and inflator is maintained through the neck's structural design and its integration with the inflation end, achieving both material efficiency and functional requirement.
Data Source
AI summary
A vehicle occupant restraint system comprises an airbag module (12) including an inflator (18) and a frontally acting airbag (16), wherein the airbag (16) includes an inflator-side inflation end (46) as well as a first free end (56) located in the inflated state of the airbag (16) within a vehicle interior. In a first period during deployment of the airbag (16), the first free end (56) is still connected via a tether (74) to the airbag module (12), wherein the tether (74) becomes detached upon reaching a predetermined tensile force. When folding the airbag (16), the non-inflated airbag (16) is spread so that a second free end (58) is maximally distant from the inflation end (46) and a first outer wall portion is stretched in the longitudinal direction of the airbag (16), and the first free end (56) is located in the vicinity of the inflation end (46) and a second outer wall portion is stretched in the longitudinal direction of the airbag (16), wherein a third outer wall portion of the airbag (16) is folded back onto itself at least in a portion. The two lateral areas of the spread airbag (16) are folded toward the center, and subsequently the airbag (16) is rolled up from the second free end (58).