Airbag Woven Fabric Geometry for Low Permeability and Flexibility
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Solution Overview
Problem
Current airbag-use woven fabrics face challenges in achieving both low air permeability and low basis weight while maintaining mechanical strength and flexibility, with existing methods either compromising on air permeability or impairing mechanical strength during folding and packaging.
Innovation Solution
The development of an airbag-use woven fabric with fibers having a substantially triangular cross-sectional shape and a modification degree of 1.3 to 2.2, which allows for low air permeability and flexibility while maintaining mechanical strength, achieved through specific spinning processes and treatment methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the fineness of fibers is reduced to lower the basis weight of the woven fabric, then the weight and volume of the airbag module are reduced, but the air permeability increases requiring a larger inflator
Solution Approach 1:
The invention changes the geometric parameters of the fiber cross-section from conventional circular shapes to specific non-circular shapes (flat, triangular, or quadrangular cross-sections). This parameter change in fiber geometry allows the fabric to achieve lower air permeability even with reduced fiber fineness, thereby enabling lighter airbag modules without requiring larger inflators to compensate for excessive air leakage.
2Weight of moving object
If the weave density is reduced to lower the basis weight, then the weight and volume are reduced, but the air permeability increases
Solution Approach 1:
The invention applies parameter changes by specifying non-circular cross-sectional shapes for the fibers (flat, triangular, or quadrangular). These geometric parameter changes in the fiber structure enable the woven fabric to maintain low air permeability properties even when the weave density is reduced, thus achieving weight reduction without compromising the air tightness required for effective airbag deployment.
3Quantity of substance
If flat cross-section yarns are used to lower air permeability, then the air permeability decreases, but the fabric rigidity increases making it difficult to fold and package
Solution Approach 1:
The invention applies local quality by specifying that only the cross-sectional shape of the individual fibers should be flat, triangular, or quadrangular, while the overall fabric structure maintains appropriate flexibility. This localized geometric modification at the fiber level achieves low air permeability without requiring the entire fabric to have high rigidity, allowing the airbag to be folded and packaged effectively.
Solution Approach 2:
The invention changes the cross-sectional geometry parameter of the fibers to flat, triangular, or quadrangular shapes, which reduces air permeability. However, by controlling the degree of flatness and combining with appropriate weave patterns, the fabric maintains sufficient flexibility for folding and packaging operations.
4Quantity of substance
If heating under pressure is applied to compress the fabric and reduce air permeability, then the air permeability decreases, but the mechanical strength is impaired
Solution Approach 1:
The invention applies preliminary action by pre-forming the fibers with flat, triangular, or quadrangular cross-sections during the spinning process. This preliminary geometric configuration of the fibers provides inherent low air permeability properties in the woven fabric, eliminating or reducing the need for subsequent heating under pressure treatments that would otherwise be required to achieve low air permeability but would damage the mechanical strength of the fabric.
Data Source
AI summary
The purpose of the present invention is to provide an airbag-use non-coated woven fabric that achieves light in weight, compact in size, and low air permeability, and an airbag-use woven fabric having low air permeability, being flexible, and exhibiting good package ability without impairing mechanical strength of the woven fabric, and an airbag that uses the airbag-use woven fabric. The airbag-use woven fabric including a base fabric, wherein a yarn widening ratio of unwoven weaving yarn of fibers that constitute the base fabric is not less than 2.4 and not more than 3.5, or including single yarn fibers having a substantially triangular cross sectional shape and a modification degree of 1.3 to 2.2; having a tear strength of not less than 120 N; and having an air permeability under a pressure difference of 20 kPa of not more than 0.65 L/cm2/min.