Motorcycle Tire with Segmented Tread Loss Tangent Design
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Solution Overview
Problem
Motorcycle tires with low fuel consumption suffer from poor grip performance, leading to potential slipping during braking and accelerating, especially in cornering and transitions between straight running and cornering.
Innovation Solution
A tire design with a radial structure featuring a center region and shoulder regions, where the center region has a smaller loss tangent for low fuel consumption and the shoulder region has a higher loss tangent for enhanced grip, along with a base layer with a low loss tangent to support both low fuel consumption and improved grip performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a rubber with small loss tangent is used for the tread to reduce energy loss, then fuel consumption is reduced, but grip performance deteriorates
Solution Approach 1:
The tread is divided into two regions with different loss tangent values: the center region has a small loss tangent (≤0.15) for low energy loss during straight running, while the shoulder region has a large loss tangent (≥0.20) for high grip performance during cornering. This local differentiation resolves the contradiction by optimizing each region for its specific function.
Solution Approach 2:
The tread is segmented into a center region and shoulder regions with distinct rubber compositions and loss tangent characteristics. The center region uses rubber with tan δ ≤ 0.15 for fuel efficiency, while the shoulder region uses rubber with tan δ ≥ 0.20 for grip, allowing simultaneous optimization of both fuel consumption and grip performance.
2Loss of energy
If the center region width is increased to improve straight running fuel consumption, then energy loss is reduced, but cornering grip performance deteriorates
Solution Approach 1:
The center region is designed with a specific width ratio (0.15 ≤ Wc/Wt ≤ 0.40) and differentiated rubber composition (tan δ ≤ 0.15) to optimize straight running fuel consumption, while the shoulder regions maintain sufficient width and high loss tangent rubber (tan δ ≥ 0.20) to ensure cornering grip performance.
3Reliability
If the shoulder region width is increased to improve cornering grip performance, then grip is enhanced, but fuel consumption increases
Solution Approach 1:
The shoulder regions are designed with sufficient width and high loss tangent rubber (tan δ ≥ 0.20) to provide excellent cornering grip performance, while the center region uses low loss tangent rubber (tan δ ≤ 0.15) to minimize energy loss during straight running, achieving both goals through local optimization.
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 low fuel consumption in straight running and high grip performance in cornering and braking, reducing the risk of slipping and enhancing overall riding stability.
Implementation Method 1
A loss tangent tan δb of the base layer is equal to or smaller than 0.15. The loss tangent tan δb of the base layer is equal to or smaller than the loss tangent tan δc of the center region.
Implementation Method 2
A loss tangent tan δs of the shoulder region is equal to or greater than 0.20 and is equal to or smaller than 0.35.
Implementation Method 3
a carcass having a radial structure
Data Source
AI summary
[Problem] It is an object to provide a tire for a motorcycle which realizes a low fuel consumption and is also excellent in a grip performance.[Means for Resolution] A tire (2) includes a tread (4) and a carcass (12) having a radial structure. The tread (4) includes a base layer (21) and a cap layer (22). The cap layer (22) has a center region (23) and a pair of shoulder regions (24) positioned on an outside in an axial direction with respect to the center region (23). A ratio (Wc/Wt) of a width (Wc) of the center region (23) to a width (Wt) of the tread (4) is equal to or higher than 0.15 and is equal to or lower than 0.4. A loss tangent (tan δc) of the center region (23) is smaller than a loss tangent (tan δs) of the shoulder region (24). A loss tangent (tan δb) of the base layer (21) is smaller than the loss tangent (tan δs) of the shoulder region (24). The loss tangent (tan δb) of the base layer (21) is equal to or smaller than 0.15. The loss tangent (tan δb) of the base layer (21) is equal to or smaller than the loss tangent (tan δc) of the center region (23).