Hybrid Cord Stress-Strain Modulus Optimization
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Solution Overview
Problem
Conventional hybrid cords used in tires face issues with physical property uniformity and manufacturing efficiency due to low initial modulus, leading to reduced driving performance and increased manufacturing costs, as well as noise and comfort degradation during high-speed driving.
Innovation Solution
A hybrid cord with a stress-strain curve featuring distinct initial, intermediate, and final modulus sections, manufactured by S-twisting low-modulus and high-modulus Z-twist yarns with specific ratios and heat treatment to optimize modulus ratios and ensure uniform properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the ratio of final tangent modulus to initial tangent modulus of hybrid cord is increased to reduce driving noise, then riding comfort is improved, but manufacturing complexity increases due to requiring old-fashioned ring twister instead of state-of-the-art direct cabler
Solution Approach 1:
The patent applies parameter changes by optimizing the twist ratios and material composition ratios within the hybrid cord. Specifically, it controls the twist ratio of aramid yarn to be 0.3-0.6 times that of polyamide 66 yarn, and sets the cross-sectional area ratio of aramid to polyamide 66 within 0.2-0.8. These parameter optimizations achieve the desired modulus ratio (≥10) and noise reduction without requiring complex manufacturing equipment, thus resolving the contradiction between noise reduction and manufacturing complexity.
2Stability of the object's composition
If polyamide 66 yarn is used as core yarn and aramid yarn as covering yarn with larger Z twist to aramid, then core-covering structure is formed, but processing efficiency decreases due to inability to use state-of-the-art direct cabler
Solution Approach 1:
The patent applies the inversion principle by reversing the conventional approach of using different twist directions for core and covering yarns. Instead, both polyamide 66 yarn and aramid yarn are twisted in the same direction (Z-twist), but with different twist ratios. The aramid yarn is twisted at 0.3-0.6 times the twist ratio of polyamide 66 yarn. This inverted approach maintains the core-covering structure stability while enabling compatibility with modern direct cabler equipment, thus resolving the contradiction between structural stability and processing efficiency.
3Ease of manufacture
If initial modulus is reduced to facilitate manufacturing, then ease of manufacture is improved, but manufacturing precision decreases due to excessive cord deformation during processing
Solution Approach 1:
The patent applies parameter changes by optimizing the initial tangent modulus to fall within 10-50 g/d and the final tangent modulus to be 100-300 g/d, achieving a ratio of ≥10. This controlled parameter optimization allows the cord to have sufficient flexibility for manufacturing while maintaining adequate stiffness to prevent excessive deformation during processing. The specific control of aramid content (0.2-0.8 cross-sectional area ratio) and twist ratios ensures both ease of manufacture and dimensional stability, resolving the contradiction between manufacturing ease and precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The hybrid cord achieves improved manufacturing efficiency, reduced differences in tire performance, enhanced riding comfort, and increased stability during high-speed driving by maintaining uniform physical properties and reducing noise.
Implementation Method 1
a hybrid cord having different physical properties on a stress-strain curve... initial tangent modulus and final tangent modulus... ratio of the final tangent modulus to initial tangent modulus
Data Source
AI summary
A hybrid cord for a tire, a method of manufacturing the same, and a high-performance environment-friendly radial tire including the same are disclosed herein. The hybrid cord includes a high-modulus fiber ply and a low-modulus fiber ply. The hybrid cord has a stress-strain curve including an initial modulus section, an intermediate modulus section and a final modulus section. The initial modulus of the initial modulus section is higher than the intermediate modulus of the intermediate modulus section, and the final modulus of the final modulus section is higher than the intermediate modulus.