Asymmetric Tread Cap Composition for High-Speed Cornering Grip
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Solution Overview
Problem
Existing pneumatic tires lack sufficient grip performance during high-speed turning, which is a safety concern on highways where long distances are traveled at high speeds.
Innovation Solution
A pneumatic tire design where the cap rubber layer on the outermost tread is divided in the tire width direction, with an outer cap rubber layer containing 25% or less styrene by mass and a glass transition temperature of -18°C or higher, and an inner cap rubber layer with a higher carbon black content, satisfying specific carbon black content and ground contact area ratios to enhance grip performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the cap rubber layer is made with high styrene content for general tread performance, then the tread durability and wear resistance are improved, but the grip performance during high-speed turning deteriorates
Solution Approach 1:
The cap rubber layer is divided into two distinct regions: an outer cap rubber layer with low styrene content (25% or less) for high-speed turning grip, and an inner cap rubber layer with higher styrene content for general tread durability. This segmentation allows each region to optimize its rubber composition for its specific functional requirements without compromising the other.
Solution Approach 2:
Different rubber compositions are applied to different locations of the cap rubber layer based on their functional requirements. The outer region uses rubber with low styrene content and higher glass transition temperature for grip during turning, while the inner region uses rubber with higher styrene content for wear resistance during straight-line driving.
2Duration of action of stationary object
If the carbon black content is increased uniformly throughout the cap rubber layer for improved wear resistance, then the tread life is extended, but the grip performance during high-speed turning is reduced
Solution Approach 1:
The carbon black distribution is segmented into two zones: the outer cap rubber layer has reduced carbon black content to maintain rubber flexibility and grip characteristics during high-speed turning, while the inner cap rubber layer has higher carbon black content to provide wear resistance and structural integrity during normal driving conditions.
Solution Approach 2:
Carbon black concentration is optimized locally for each region's performance requirements. The outer region maintains lower carbon black content (3-30 parts by mass) to preserve rubber elasticity for gripping during turning maneuvers, while the inner region has higher carbon black content for enhanced abrasion resistance during straight-line operation.
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 tire achieves significantly improved grip performance during high-speed turning by optimizing the rubber composition and carbon black distribution, ensuring better traction and safety on highways.
Implementation Method 1
the cap rubber layer located on the outside of the vehicle is formed of a rubber composition containing 25% by mass or less of styrene in the rubber component and having a glass transition temperature of -18°C or higher
Data Source
Figure 1
Figure 2(a)~2(b)
AI summary
A pneumatic tire that specifies the tire mounting direction when mounted on a vehicle and has sufficiently improved grip performance at high-speed turning is provided in which the cap rubber layer 21 on the outermost layer of the tread2 is divided in the tire width direction, the cap rubber layer 21a located on the outside of the vehicle is formed of a rubber composition containing 25% by mass or less of styrene tn the rubber component and having a glass transition temperature of -18°C or higher, and wherein the carbon black content ratio is Cout (mass%). and the ground contact area ratio is Lout in the cap rubber layer located on the outside of the vehicle, and the carbon black content ratio is Cin (mass%) and the ground contact area ratio is Lin in the cap rubber layer located inside the vehicle, the following (Formula I) and (Formula 2) are satisfied Cin<Cout (Formula 1) 0 ≤ (Cout * Lout) - (Cin x Lin) (Formula 2).