Knee Airbag Diffuser Segmentation for Rapid Deployment
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Solution Overview
Problem
Knee airbags face choking issues during deployment due to the closure of outlet ports at both ends of the tubular diffuser, leading to incomplete inflation and protection in narrow spaces.
Innovation Solution
A knee airbag design featuring a cylinder-type inflator with a diffuser that uses folded hexagonal cloths and orthogonal creases to prevent choking, allowing for rapid deployment by keeping the lower base short and the inflator close to the lower base, ensuring gas outlet ports remain open.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the diffuser is made long to guide gas at high speed, then the airbag deployment speed is improved, but the outlet ports are closed by folding causing choking
Solution Approach 1:
The diffuser is divided into multiple sections with different folding characteristics. The first folding section has creases that engage during accommodation, while the second folding section maintains open outlet ports. This segmentation allows the diffuser to be long enough for high-speed gas flow while preventing choking by having different sections behave differently during folding.
Solution Approach 2:
Different portions of the diffuser are given different local qualities - the first folding section has creases positioned to engage with folds for compact accommodation, while the second folding section has its creases positioned to remain engaged and keep outlet ports open. This local differentiation resolves the contradiction between needing length for speed and preventing choking for reliability.
2Volume of moving object
If the diffuser is folded compactly for accommodation, then the device compactness is improved, but the outlet ports are closed causing choking
Solution Approach 1:
The diffuser is segmented into first and second folding sections with different crease positions. During accommodation, both sections fold compactly to reduce volume. During deployment, the first section's creases engage to maintain compactness while the second section's creases remain engaged to prevent choking, ensuring reliable deployment despite compact folding.
Solution Approach 2:
The solution addresses the folding problem by considering the diffuser in multiple dimensions - the longitudinal dimension for gas flow and the radial dimension for folding. By positioning creases at different radial positions in different sections, the design achieves compact accommodation in one dimension while maintaining outlet port openness in another dimension.
3Stability of the object's composition
If the lower base is made long to engage with creases, then the structural stability is improved, but the outlet ports are closed causing choking
Solution Approach 1:
The diffuser structure is segmented into different folding sections with differentiated crease engagement. The first folding section provides structural stability through crease engagement, while the second folding section maintains outlet port openness. This segmentation allows the lower base to have different engagement characteristics in different sections, achieving both stability and preventing choking.
Data Source
AI summary
An airbag in which no choking occurs and which can be rapidly deployed. A cushion section of the airbag internally accommodates a cylinder-type inflator that includes an insertion hole for inserting the inflator from an outside to an inside, and a diffuser into which the inflator is inserted, and a diffuser having a tubular portion obtained by folding back a section of cloth to form symmetrical portions with an upper base formed by the folded back part and a lower base formed by adjacent ends of the symmetrical portions. The cushion section is folded back at both lateral sides of the along first folding lines that are substantially orthogonal to a longitudinal direction of the diffuser.