Single-Ply Tire Carcass Structure to Prevent Open Thread
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Solution Overview
Problem
The challenge is to reduce the mass of a tire while maintaining carcass strength and preventing open thread formation, which affects appearance quality, especially when using a single carcass ply instead of two, as the interval between carcass cords widens, leading to potential open thread occurrences.
Innovation Solution
A tire design featuring a single carcass ply with thicker cords (6000-9000 dtex) and an insulation layer between the carcass and inner liner, where the ratio of topping rubber thickness to insulation thickness is between 0.2 and 0.6, and the complex elastic modulus ratio of insulation to outer layer is between 1.0 and 2.0, to prevent open thread formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the number of carcass plies is reduced from two to one to achieve mass reduction, then the tire mass decreases, but the strength of the carcass decreases and the interval between carcass cords widens causing open thread formation
Solution Approach 1:
The patent changes the parameter of cord fineness from conventional values to 6000-9000 dtex, making cords thicker while maintaining the same linear density. This parameter change allows single-ply construction to achieve both mass reduction and sufficient strength, as the thicker cords provide the necessary load-bearing capacity while occupying less space, thereby preventing open thread formation
Solution Approach 2:
The patent uses a composite structure combining thick carcass cords (6000-9000 dtex) with specific rubber compositions and insulation layers. This composite approach creates a single-ply carcass that achieves the strength of traditional two-ply constructions while reducing mass, as the optimized material combination compensates for the reduced ply count
2Weight of moving object
If the number of carcass plies is reduced from two to one to achieve mass reduction, then the tire mass decreases, but open thread formation occurs affecting appearance quality
Solution Approach 1:
The patent changes the cord fineness parameter to 6000-9000 dtex, which increases cord thickness and reduces the number of cords needed. This parameter change directly prevents open thread formation by ensuring sufficient cord coverage while maintaining single-ply construction, thereby preserving appearance quality alongside mass reduction
3Strength
If thicker cords (6000-9000 dtex) are used to maintain carcass strength in a single ply, then the strength is maintained, but the interval between cords widens at the buttress portion causing open thread
Solution Approach 1:
The patent applies local quality by providing insulation layers at specific locations, particularly at the buttress portion where open thread is most likely to occur. The insulation layer is positioned between the inner liner and carcass at this critical region, providing localized protection against open thread formation while maintaining the overall single-ply structure with thicker cords
Solution Approach 2:
The patent introduces an insulation layer as an intermediary element between the inner liner and the carcass cords. This intermediary layer fills the gaps between thicker cords at the buttress portion, preventing the inner liner from contacting and forming open threads, while allowing the thicker cord structure to maintain carcass strength
Data Source
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AI summary
Provided is a tire 2 that can achieve mass reduction while suppressing a decrease in the strength of a carcass without impairing appearance quality. The tire 2 includes a pair of beads 10, a carcass 12, an inner liner 20, and an insulation 22 located between the carcass 12 and the inner liner 20. The carcass 12 includes one carcass ply 42. The carcass ply 42 includes a plurality of carcass cords 44 and a topping rubber 46. Each carcass cord 44 has a total fineness of not less than 6000 dtex and not greater than 9000 dtex. The insulation 22 is located between first and second beads 10. A ratio (ta/td) of a thickness ta of the topping rubber 46 located between the insulation 22 and the carcass cords 44 to a thickness td of the insulation 22 is not less than 0.2 and not greater than 0.6.