Curtain Airbag Second Internal Seam Longitudinal Contraction
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Solution Overview
Problem
Curtain airbags often contract longitudinally when deployed over a curved vehicle cant rail, leading to reduced coverage area and potential wrinkle formation, which can cause the airbag to be pulled away from intended protection zones, especially affecting rear occupants.
Innovation Solution
Incorporating a second internal seam at the longitudinal end portions of the airbag, which contracts in the height direction, allowing the airbag to adapt to the cant rail curvature and maintain coverage by extending the rear or front lower corners, thereby counteracting longitudinal contraction and wrinkle risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the airbag is deployed over a curved cant rail, then the airbag adapts to the curved shape, but longitudinal contraction occurs and coverage area is reduced
Solution Approach 1:
The airbag is divided into multiple longitudinal segments by introducing a second longitudinal seam that creates a second airbag cell adjacent to the first airbag cell. This segmentation allows each cell to independently adapt to the curved cant rail shape while maintaining overall longitudinal extension, preventing the entire airbag from contracting uniformly.
Solution Approach 2:
The invention introduces an additional longitudinal dimension by creating a second airbag cell through the second longitudinal seam. This additional dimension provides extra longitudinal coverage that compensates for the contraction that occurs when the airbag adapts to the curved cant rail, effectively adding length in the longitudinal direction.
2Adaptability or versatility
If the airbag adapts to curved cant rail shape, then coverage is maintained, but wrinkles are created and airbag is pulled away from intended zones
Solution Approach 1:
By segmenting the airbag into multiple longitudinal cells separated by the second longitudinal seam, each cell can independently conform to the curved cant rail shape. This reduces the formation of large wrinkles and prevents the airbag from being pulled away from its intended coverage zones, as each segment can adapt locally without affecting the entire airbag structure.
Solution Approach 2:
The second longitudinal seam creates local structural variations that allow different parts of the airbag to have different adaptation characteristics. The additional airbag cell provides localized longitudinal extension at critical areas (front or rear depending on where the seam is positioned), ensuring reliable coverage of intended zones while adapting to the overall curved shape.
3Ease of manufacture
If a straight upper longitudinal edge is used, then manufacturing is simplified, but the airbag does not adapt well to curved cant rails
Solution Approach 1:
The airbag is segmented into multiple longitudinal cells by the second longitudinal seam, allowing the upper longitudinal edges to maintain a relatively straight configuration during manufacturing while the inflated structure adapts to the curved cant rail. The segmentation enables the airbag to achieve curvature adaptation through the three-dimensional inflation of multiple cells rather than requiring a pre-curved flat pattern.
Data Source
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AI summary
The present disclosure relates to an inflatable airbag (110) adapted to deploy in a curtain-like shape over a side surface of a vehicle interior for protecting a vehicle occupant. The airbag (110) comprises a circumferential seam (122) along substantially its entire circumference. The airbag (110) further comprises at least a first internal seam (124, 126). The airbag (110) comprises a second internal seam (146) in at least one of a first or second longitudinal end portion (134, 136). The second internal seam (146) extends substantially in the longitudinal direction between a first end point (148) adjacent to the circumferential seam (122) and a second end point (150) located longitudinally closer to the centre of the airbag (110) than the first end point (148). The second internal seam (146) forms together with a portion of the circumferential seam (122) a longitudinally extending airbag cell (152).The second end point (150) is spaced from any of the at least a first internal seam (124, 126) and the circumferential seam (122) by a distance (r) of at least 10 cm, preferably at least 15 cm and most preferably at least 20 cm, such that, when the airbag (110) is deployed, the longitudinally extending airbag cell (152) is pressurized at substantially the same rate as the rest of the inflatable portion of the airbag (110). The disclosure further relates to a vehicle comprising such an inflatable airbag and the use of a second internal seam.