Airbag Restriction Yarn Segmentation for Thickness Control
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Solution Overview
Problem
Existing airbag designs face challenges in balancing the control of inflated shape and thickness, particularly when minimizing the amount of gas used for deployment, as they rely heavily on the length of restriction yarns which can lead to uneven thickness and difficulty in maintaining shape consistency across different vehicle models.
Innovation Solution
The airbag incorporates a specific arrangement of restriction yarns, including first, second, and third yarns forming alternating units, with varying lengths and configurations, to uniformly control the thickness and shape of the inflated airbag, ensuring consistent performance across different vehicle types by distributing stress evenly and preventing rupture at high pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the length of restriction yarn is increased to control inflated thickness, then the thickness control is improved, but the inflated shape control deteriorates
Solution Approach 1:
The restriction yarn is divided into multiple segments with different lengths arranged in an alternating pattern. Short segments restrict thickness in certain regions while long segments allow greater expansion in other regions, enabling simultaneous control of both thickness and inflated shape that cannot be achieved with uniform yarn lengths.
Solution Approach 2:
Different segments of the restriction yarn have different lengths tailored to specific locations within the airbag. This local variation in yarn length allows optimization of thickness and shape control for different regions of the airbag independently, resolving the contradiction between uniform thickness control and overall shape control.
2Volume of moving object
If the amount of gas in the inflator is reduced to miniaturize the inflator, then the inflator size is improved, but the inflation performance deteriorates
Solution Approach 1:
The restriction yarn segments create multiple localized inflation zones that can inflate efficiently with less gas. By dividing the airbag into regions with different restriction characteristics, the system achieves reliable inflation performance with reduced gas volume compared to a fully unrestricted single-zone inflation.
Solution Approach 2:
The varying lengths of restriction yarn segments change the physical parameters of inflation resistance across different regions. This creates a gradient of inflation pressures that allows effective deployment with smaller gas volumes, as gas is directed preferentially to regions with appropriate restriction levels rather than requiring uniform high pressure throughout.
3Ease of manufacture
If uniform restriction yarn length is used to simplify manufacturing, then the manufacturing complexity is improved, but the inflated shape uniformity deteriorates
Solution Approach 1:
The restriction yarn is manufactured as segmented units with different lengths that can be alternately arranged. This segmentation allows for standardized production of discrete yarn segments that maintain manufacturing simplicity while achieving uniform inflated shape through their alternating pattern arrangement.
Solution Approach 2:
Multiple yarn segments of different lengths are combined in an alternating pattern to create a composite restriction structure. This merging of different length segments achieves shape uniformity that neither short nor long uniform yarns could provide alone, while maintaining manufacturing feasibility through modular assembly.
Data Source
Figure 1A~2B
Figure 3A~3D
Figure 4A~4D
AI summary
Provided is a bag body which has a flatter shape in its expanded state. This bag body has control yarn therein, which controls expansion. The control yarn includes: a first seam which extends from a non-expansion section to another non-expansion section within the bag body; a second seam which is a seam forming the fabric on one surface of the expansion section of the bag body, and is formed by being separated from the fabric on said one surface, threaded through the first seam, and turned back to the fabric on said one surface; and a third seam which is a seam forming the fabric on the other surface of the expansion section of the bag body, and is formed by being separated from the fabric on the other surface, threaded through the first seam, and turned back to the fabric on the other surface. A control seam group, which is configured from the first to third seams, includes: a first seam unit that is configured such that the two or more second seams alone are consecutively threaded through the first seam; and a second seam unit that is configured such that the two or more third seams alone are consecutively threaded through the first seam. The first and second seam units are alternately arranged in the direction in which the first seam extends.