Pedestrian Airbag Retraction Mechanism
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Solution Overview
Problem
Existing airbag devices for pedestrian protection struggle to compactly retract after deployment, obstructing the driver's view due to their size and deployment mechanism.
Innovation Solution
An airbag device with a flexible protecting sheet and wrapping sheet that includes straps and a rupturable portion, allowing the airbag to be shrunk and tied back into storage using straps that pass through holes in the wrapping sheet, facilitating compact retraction without hindering deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the airbag is deployed over the windshield to protect pedestrians, then pedestrian protection is improved, but the driver's eyesight is obstructed and the airbag occupies excessive space
Solution Approach 1:
The airbag is designed to dynamically change its state from deployed to retracted. The system transitions the airbag from a deployed state (covering the windshield for pedestrian protection) to a retracted state (pulled back into the storage compartment). This dynamic transformation resolves the contradiction by making the airbag size adaptable to different operational requirements.
Solution Approach 2:
The airbag is temporarily deployed for pedestrian protection and then recovered back into its storage compartment. The retraction mechanism pulls the airbag back into the storage space, effectively 'discarding' its deployed position and 'recovering' it to a compact stored state, thus resolving the space occupation issue while maintaining protection capability when needed.
2Reliability
If the airbag remains deployed over the windshield, then pedestrian protection is maintained, but the driver's visibility is reduced
Solution Approach 1:
The airbag system dynamically adjusts its position between deployed and retracted states. After serving its pedestrian protection function, the airbag is pulled back into the storage compartment, dynamically transitioning from an obstructive position to a non-obstructive position, thereby restoring driver visibility while maintaining protection capability when needed.
Solution Approach 2:
The airbag undergoes periodic deployment and retraction cycles. It is deployed when pedestrian protection is needed and retracted when not needed, creating a periodic action pattern that alternates between protecting pedestrians and ensuring driver visibility, thus resolving the contradiction between these two requirements.
3Ease of manufacture
If the airbag is designed with a simple structure, then manufacturing is easier, but the retraction and compacting function is insufficient
Solution Approach 1:
The airbag structure is segmented into multiple functional components: the airbag itself, the protecting sheet with straps, and the wrapping sheet. This segmentation allows each component to perform a specific function (protection, retraction, compacting) while maintaining overall manufacturing simplicity. The straps and wrapping sheet can be separately manufactured and then assembled, easing the manufacturing process while achieving effective retraction and compactness.
Solution Approach 2:
The protecting sheet and wrapping sheet act as intermediary components between the airbag and the storage compartment. These intermediaries facilitate the retraction and compacting functions without requiring complex mechanisms integrated into the airbag itself. The straps on the protecting sheet and the wrapping sheet with through holes work together to pull and secure the airbag, achieving compact retraction while keeping the airbag structure simple and easy to manufacture.
Data Source
AI summary
An airbag device for pedestrian protection includes means for shrinking and tying an airbag after deployment toward the storage. The airbag device includes a protecting sheet that is folded together with the airbag and stored in the storage, and a wrapping sheet that wraps the airbag as folded. The protecting sheet includes a main body and a plurality of straps disposed in a periphery of the main body. The wrapping sheet includes a rupturable portion that is configured to rupture and split the wrapping sheet into a front portion and a rear portion at airbag deployment, and a plurality of through holes each for receiving the straps in a vicinity of the rupturable portion in the front portion. The deployed airbag is shrank and tied toward the storage by passing the straps through the through holes and tying them so the straps do not come off of the through holes.