Three-Layer Tire Tread Structure for Low Rolling Resistance
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Solution Overview
Problem
Existing tires face a challenge in achieving reduced rolling resistance without compromising wet performance, as the use of rubbers with low heat generation properties for treads leads to decreased grip force, particularly on wet road surfaces.
Innovation Solution
A tire design with a three-layer tread structure comprising a cap layer, an intermediate layer, and a base layer, where the loss tangent of the intermediate layer is lower than the cap layer, and the cap layer thickness is strategically distributed to maintain grip performance while reducing rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a rubber with low heat generation properties is used for the tread, then rolling resistance is reduced, but grip performance on wet road surfaces is decreased
Solution Approach 1:
The tread is divided into three distinct layers (cap layer, intermediate layer, base layer) with different rubber compositions and loss tangent values. The cap layer uses high loss tangent rubber for wet grip, the base layer uses low loss tangent rubber for low rolling resistance, and the intermediate layer bridges the two properties, allowing the tire to achieve both low rolling resistance and good wet performance simultaneously
Solution Approach 2:
Different regions of the tread are assigned different rubber properties tailored to their specific functions. The cap layer at the contact patch prioritizes wet grip performance with higher loss tangent rubber, while the base layer prioritizes energy efficiency with lower loss tangent rubber. The intermediate layer provides a gradient transition, creating local quality variations that optimize overall tire performance
2Loss of energy
If a three-layer tread structure with intermediate rubber is adopted, then rolling resistance is reduced, but wet performance may be decreased due to inferior grip force of intermediate rubber
Solution Approach 1:
The loss tangent values of the three layers are specifically controlled within defined ranges: cap layer (0.10-0.30), intermediate layer (0.08-0.25), and base layer (0.06-0.20). This parameter optimization ensures the intermediate layer provides sufficient grip force while maintaining the overall low rolling resistance benefit of the three-layer structure
Solution Approach 2:
The tread combines three different rubber compositions with progressively decreasing loss tangent values from cap to base layer. This composite structure allows the tire to integrate the advantages of different rubber types: high grip force from cap rubber, low rolling resistance from base rubber, and balanced properties from intermediate rubber, achieving superior overall performance
3Reliability
If the cap layer thickness is increased to maintain wet performance, then grip force is improved, but rolling resistance increases due to higher heat generation properties
Solution Approach 1:
The cap layer thickness is optimized to provide sufficient wet grip at the contact patch without excessive overall thickness that would increase rolling resistance. The intermediate layer compensates for any reduction in cap layer thickness by providing adequate grip force with lower heat generation, allowing thin cap layer design that maintains wet performance while reducing overall rolling resistance
Solution Approach 2:
The thickness ratios of cap layer, intermediate layer, and base layer are specifically controlled to optimize the balance between wet performance and rolling resistance. The cap layer thickness ratio and intermediate layer thickness ratio are defined within specific ranges to ensure the cap layer provides sufficient wet grip while the intermediate and base layers compensate with lower loss tangent properties to maintain low rolling resistance
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 reduced rolling resistance and maintained wet performance by optimizing the thickness and loss tangent properties of the tread layers, ensuring effective grip even after wear.
Implementation Method 1
a loss tangent at 30°C of the intermediate layer is lower than a loss tangent at 30°C of the cap layer; a loss tangent at 30°C of the base layer is lower than the loss tangent at 30°C of the intermediate layer
Data Source
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AI summary
A tire 2 includes a tread 4 including a plurality of layers 48 including a cap layer 50, an intermediate layer 52, and a base layer 54. A loss tangent at 30°C of the intermediate layer 52 is lower than a loss tangent at 30°C of the cap layer 50. A loss tangent at 30°C of the base layer 54 is lower than the loss tangent at 30°C of the intermediate layer 52. The tread 4 includes a first tread 60 and a second tread 62. A ratio of a thickness of the cap layer 50 in the second tread 62 to a thickness of the tread 4 is not less than 5% and not greater than 25%. A ratio of the thickness of the cap layer 50 in the first tread 60 to the thickness of the tread 4 is not less than 35% and not greater than 55%.