Pneumatic Tire Cap Rubber Segmentation for Wet Grip and Rolling Resistance
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Solution Overview
Problem
Conventional pneumatic tires face challenges in balancing rolling resistance and wet grip performance while experiencing uneven wear, as existing solutions either compromise on rolling resistance or wet grip due to the limitations of using single compounds with specific tan δ values and configurations.
Innovation Solution
A pneumatic tire design with compounds having different physical properties in the center and shoulder regions, where the center portion has a higher tan δ at 0°C for improved wet grip and the shoulder portions have a lower tan δ at 60°C for reduced rolling resistance, with specific JIS A hardness and groove configurations to prevent uneven wear and enhance deformation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a rubber with low tan δ at 60°C is used in the cap rubber to reduce rolling resistance, then rolling resistance is reduced, but wet grip performance deteriorates
Solution Approach 1:
The cap rubber is divided into multiple regions (center region and shoulder regions) with different compound formulations. The center region uses a compound optimized for rolling resistance, while the shoulder regions use a compound optimized for wet grip performance, allowing each region to independently optimize its function without compromising the other.
Solution Approach 2:
Different physical properties are assigned to different locations of the cap rubber. The shoulder portions have compounds with higher tan δ at 0°C for improved wet grip, while the center portion has compounds with lower tan δ at 60°C for reduced rolling resistance, creating local optimization of material properties according to functional requirements.
2Reliability
If a rubber with high tan δ at 0°C is used in the cap rubber to improve wet grip performance, then wet grip performance is improved, but rolling resistance increases
Solution Approach 1:
The cap rubber is divided into multiple regions (center region and shoulder regions) with different compound formulations. The center region uses a compound optimized for rolling resistance, while the shoulder regions use a compound optimized for wet grip performance, allowing each region to independently optimize its function without compromising the other.
Solution Approach 2:
Different physical properties are assigned to different locations of the cap rubber. The shoulder portions have compounds with higher tan δ at 0°C for improved wet grip, while the center portion has compounds with lower tan δ at 60°C for reduced rolling resistance, creating local optimization of material properties according to functional requirements.
3Ease of operation
If soft rubber is disposed in the center region to improve comfort, then comfort is improved, but uneven wear occurs more easily
Solution Approach 1:
The hardness parameter of the rubber compound is carefully controlled within a specific range (JIS A 60-80) to balance comfort and wear resistance. This parameter optimization ensures that the rubber remains soft enough for comfort while maintaining sufficient durability to prevent uneven wear.
Solution Approach 2:
The patent uses composite rubber compounds with specific formulations that combine multiple materials and additives to achieve the desired balance between softness for comfort and hardness for wear resistance, creating a material that satisfies both contradictory requirements.
4Loss of energy
If a rubber emphasizing rolling resistance is disposed in the center portion and a rubber emphasizing wet grip performance is disposed in the shoulder portion, then rolling resistance is reduced, but uneven wear occurs
Solution Approach 1:
The hardness parameter of the rubber compound is carefully controlled within a specific range (JIS A 60-80) to balance comfort and wear resistance. This parameter optimization ensures that the rubber remains soft enough for comfort while maintaining sufficient durability to prevent uneven wear.
Solution Approach 2:
The patent uses composite rubber compounds with specific formulations that combine multiple materials and additives to achieve the desired balance between softness for comfort and hardness for wear resistance, creating a material that satisfies both contradictory requirements.
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 a balance between rolling resistance and wet grip performance while suppressing uneven wear, improving grip on wet surfaces and reducing fuel consumption by strategically positioning compounds and forming circumferential narrow grooves to manage deformation and rigidity.
Implementation Method 1
a compound with a tan δ at 0° C. that is higher than that of a compound in both the shoulder portions is disposed in the center portion
Implementation Method 2
a compound with a tan δ at 60° C. that is lower than the compound in the center portion is disposed in both the shoulder portions
Data Source
AI summary
The present technology provides a pneumatic tire that combines rolling resistance and wet grip performance while suppressing the occurrence of uneven wear. The pneumatic tire of the present technology has a cap rubber divided into a center portion that straddles a tire equator line and shoulder portions positioned on both sides thereof, a compound emphasizing wet grip performance and having a tan δ at 0° C. higher than that of the shoulder portions is disposed in the center portion and a compound emphasizing rolling resistance and having a tan δ at 60° C. lower than that of the center portion is disposed in both shoulder portions, and circumferential narrow grooves are formed on the respective shoulder sides of outermost main grooves in both the shoulder portions.