External Tether Airbag Deployment Control
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Solution Overview
Problem
Existing airbag systems face challenges in balancing the protection of 'in-position' and 'out-of-position' occupants during collisions, as internal tethers and breakable tethers struggle to effectively control and tune airbag deployment characteristics.
Innovation Solution
An externally tethered airbag system that moves between an expansion-constrained and expanded position, utilizing a tether that increases in length to constrain and control the airbag's expansion, directing 'out-of-position' occupants towards the central contact area for improved force absorption, while maintaining a vertical contact face profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If internal tethers or breakable tethers are used to control airbag deployment, then the airbag can be constrained during deployment, but tuning the deployment characteristics becomes difficult
Solution Approach 1:
The tether is designed with a dynamic length change capability, transitioning from a constrained shorter position to an extended longer position during airbag deployment. This dynamic adjustment allows the tether to provide initial constraint force while eventually allowing full airbag expansion, solving the tuning difficulty without adding complex mechanical adjustment mechanisms.
Solution Approach 2:
The tether's length parameter is changed during the deployment process. By designing the tether to naturally transition between length states in response to deployment forces, the system achieves tunable deployment characteristics through a single parameter change rather than complex multi-component mechanisms.
2Speed
If the airbag expands freely without constraint, then deployment speed is fast, but protection for out-of-position occupants is insufficient
Solution Approach 1:
The tether applies a preliminary constraining force during the early phase of airbag deployment to shape the expanding airbag and direct it toward out-of-position occupants. This preliminary action ensures proper force distribution before the airbag fully expands, improving protection reliability without significantly delaying overall deployment speed.
3Force
If the tether constrains the airbag expansion, then force absorption is improved, but the tether must withstand high expansion forces
Solution Approach 1:
The tether's constraint force is dynamic rather than static. It provides maximum constraint during early deployment when force absorption is most needed, then naturally relaxes as the airbag expands fully. This dynamic behavior allows the tether to achieve high force absorption with moderate strength requirements through proper timing of constraint application.
Data Source
AI summary
An example airbag arrangement includes an airbag that moves between an expansion-constrained position and an expanded position. A tether adjacent an exterior surface of the airbag moves with the airbag between a shorter position and a longer position. The tether remains intact in the shorter position and the longer position. When the tether is in the shorter position, the tether holds the airbag in the expansion-constrained position.