PET Cap Ply Cord Structure for High-Speed Radial Tire Durability
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Solution Overview
Problem
Conventional cap ply materials for radial tires, such as nylon 66 and aramid fibers, face challenges in high-speed durability and fatigue resistance, with aramid fibers being costly and vulnerable to heat, while PET fibers are difficult to apply due to heat sensitivity.
Innovation Solution
A radial tire with a cap ply layer using polyethylene terephthalate dip cords, characterized by a high strength, low elongation, and specific shrinkage rate, which improves the tire's high-speed durability and adhesive force with rubber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If nylon 66 is used as cap ply material to achieve high shrinkage and heat resistance, then the tire maintains shape stability at high temperatures, but the material cost increases and adhesion to rubber decreases due to heat
Solution Approach 1:
The patent applies parameter changes by controlling the crystallinity of PET fibers within a specific range of 20-40% and adjusting the dip cord structure. This allows PET to exhibit heat shrinkage properties similar to nylon 66 while maintaining better adhesion to rubber, thus resolving the contradiction between heat resistance and adhesion reliability
Solution Approach 2:
The patent uses PET material which is more cost-effective compared to aramid fibers, while achieving comparable performance through controlled crystallinity and dip cord structure, thus providing an economical alternative that maintains reliability
2Stability of the object's composition
If aramid fiber is used as cap ply material to achieve stability at high temperatures, then deformation is suppressed, but the fatigue resistance decreases and manufacturing cost increases significantly
Solution Approach 1:
The patent replaces expensive aramid fibers with PET material that has been optimized through controlled crystallinity (20-40%) and dip cord structure. This substitution maintains the stability at high temperatures while improving fatigue resistance and reducing cost, effectively resolving the contradiction between stability and strength
Solution Approach 2:
By changing the crystallinity parameter of PET to a specific range and optimizing the dip cord configuration, the patent achieves temperature stability comparable to aramid while significantly improving fatigue resistance, thus resolving the strength contradiction
3Ease of manufacture
If PET fiber is used as cap ply material to reduce cost, then manufacturing cost decreases, but the material becomes vulnerable to heat and difficult to apply
Solution Approach 1:
The patent transforms PET from a heat-vulnerable material to a heat-resistant one by controlling its crystallinity within 20-40% and optimizing the dip cord structure. This parameter change enables PET to withstand high temperatures during tire operation while maintaining cost advantages, thus resolving the contradiction between manufacturing cost and heat resistance
Solution Approach 2:
The patent successfully uses cost-effective PET material by optimizing its structural parameters, transforming it from an unsuitable low-cost material to a viable alternative that maintains both affordability and heat resistance performance
4Stability of the object's composition
If cap ply cord has high elastic modulus to prevent deformation, then tire shape stability improves, but the work loss increases due to repeated deformation cycles
Solution Approach 1:
The patent optimizes the balance between elastic modulus and energy dissipation by controlling PET crystallinity and dip cord structure. This creates a cap ply that provides sufficient shape stability while minimizing work loss through repeated deformation cycles, resolving the contradiction between stability and energy loss
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 polyethylene terephthalate dip cords enhance the tire's high-speed durability, fatigue resistance, and adhesive strength, overcoming the limitations of conventional materials while maintaining cost-effectiveness.
Implementation Method 1
when the temperature rises, the heat shrinkage force is expressed and the cap fly cord contracts, so that a material that can prevent the size increase during driving of the tire is used
Implementation Method 2
the polyethylene terephthalate dip cords enhance the tire's high-speed durability, fatigue resistance, and adhesive strength
Data Source
AI summary
Disclosed is a radial tire having a cap ply manufactured with a polyethylene terephthalate dip cord. The radial tire includes: a pair of parallel bead cores; at least one radial carcass ply wound around the bead cores; one or more inclined belt layers layered on the outer circumference of the carcass ply; and one or more cap ply layers layered in the circumferential direction of a tire on the outer circumference of the inclined belt layers, wherein the cap ply includes a dip cord manufactured using a yarn comprising 90 mol % or more of polyethylene terephthalate, and the dip cord has a shrinkage of 3.0-4.0%, a strength of 2.5-3.0 g/d at an elongation of 5%, a breaking strength of 6.5-7.5 g/d, and a dimensional stability index of 5.8-6.5.