Small-Diameter Tire Tread Layout for Wet Grip and Wear Resistance
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Solution Overview
Problem
Small-diameter tires face challenges in achieving both wet performance and wear resistance while maintaining a compatible load capacity, as existing designs often compromise on one performance aspect due to limitations in rotational inertia and weight.
Innovation Solution
A tire design incorporating a pair of bead cores, a carcass layer extended across the bead cores, and a belt layer disposed radially outside the carcass layer, with specific groove area ratios and material properties to ensure both wet performance and wear resistance, including a cap tread and undertread with defined rubber hardness and modulus ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the groove area ratio of the tread portion is increased to improve wet performance, then wet performance is improved, but wear resistance performance deteriorates
Solution Approach 1:
The patent applies local quality by differentiating the groove area ratios in different regions of the tread portion. The center region has a higher groove area ratio (Ace) for improved wet performance, while the shoulder region has a lower groove area ratio (Ash) to maintain wear resistance. This spatial differentiation of groove characteristics allows each region to optimize for its specific functional requirements.
2Weight of moving object
If the tire diameter is reduced to decrease rotational inertia and weight, then transportation cost is reduced, but load capacity deteriorates
Solution Approach 1:
The patent employs composite materials in the belt layer, combining steel belts with high-modulus polymer materials. This composite construction provides enhanced strength-to-weight ratio, allowing the small-diameter tire to maintain adequate load capacity while keeping the overall weight low. The composite structure distributes stresses more effectively across the tire components.
3Reliability
If the groove area ratio Ace of the center region is increased relative to the shoulder region to ensure wet performance, then wet performance is improved, but the overall structural balance deteriorates
Solution Approach 1:
The patent utilizes parameter changes by establishing specific quantitative relationships between groove area ratios in different regions. The condition Ace/Ash > 1.1 defines a precise parameter range that balances wet performance improvement with structural integrity. This quantitative approach ensures that while the center region has enhanced grooves for wet traction, the shoulder region maintains sufficient groove area to preserve overall tire stability and load distribution.
Data Source
AI summary
A tire includes a pair of bead cores, a carcass layer extended across the bead cores, a belt layer disposed on an outer side of the carcass layer in a radial direction, and a tread portion. A tire outer diameter OD (mm) is in a range 200≤OD≤660. A total tire width SW (mm) is in a range 100≤SW≤400. A groove area ratio Aa of the tread portion is in a range 0.008≤Aa/OD≤0.150. A groove area ratio Ace of a center region of the tread portion and a groove area ratio Ash of a shoulder region of the tread portion have a relationship Ace/Ash>1.