Three-Layer Tire Tread Structure for Low Rolling Resistance Grip
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Solution Overview
Problem
Existing tires face a challenge in reducing rolling resistance while maintaining grip performance, as conventional methods to decrease rolling resistance often compromise grip.
Innovation Solution
A tire design with a three-layer tread structure, comprising a cap layer, intermediate layer, and base layer with varying loss tangents, and circumferential narrow grooves on the shoulder land portion to reduce rolling resistance without significantly affecting grip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the number of components or thicknesses of components in the tread are decreased to reduce rolling resistance, then rolling resistance is reduced, but grip performance deteriorates
Solution Approach 1:
The tread is divided into three distinct layers (cap layer, intermediate layer, base layer) with different material compositions and loss tangent values. This segmentation allows each layer to perform its specific function: the cap layer provides grip performance with higher loss tangent, while the base layer reduces rolling resistance with lower loss tangent, and the intermediate layer transitions between them.
Solution Approach 2:
Different regions of the tread are given different material properties through the three-layer structure. The cap layer at the outermost position has higher loss tangent for grip, the intermediate layer has medium loss tangent, and the base layer has lower loss tangent for rolling resistance reduction. This local differentiation of material quality optimizes both grip and fuel efficiency.
2Loss of energy
If a circumferential narrow groove is formed on the shoulder land portion, then rolling resistance is reduced, but the structure becomes more complex
Solution Approach 1:
The groove width is precisely controlled within a specific range (2.5%-3.5% of tread width) to optimize the balance between rolling resistance reduction and structural simplicity. The tapered shape with specific dimensional parameters allows the groove to effectively reduce contact area and rolling resistance while maintaining manufacturability and avoiding excessive complexity.
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 design achieves a reduction in rolling resistance while effectively preserving grip performance by optimizing the tread's structural layers and groove configurations.
Implementation Method 1
The tread includes a cap layer, an intermediate layer having a loss tangent at 30°C lower than a loss tangent at 30°C of the cap layer, and a base layer having a loss tangent at 30°C lower than the loss tangent at 30°C of the intermediate layer. The loss tangent is measured using a viscoelasticity spectrometer
Implementation Method 2
A circumferential narrow groove is formed on the shoulder land portion so as to continuously extend in the circumferential direction. The circumferential narrow groove is tapered from a groove opening toward a groove bottom. A ratio of a groove width at the groove opening of the circumferential narrow groove to a width of the tread is not less than 2.5% and not greater than 3.5%.
Data Source
Figure 1
Figure 2(A)~2(C)
Figure 3
AI summary
Atire 2 includes a tread 4 and a belt 14. The tread 4 includes a cap layer 38, an intermediate layer 40, and a base layer 42. The belt 14 includes an inner layer 34 and an outer layer 36. A plurality of circumferential main grooves 52 are formed on the tread 4, and at least three land portions 54 are formed in the tread 4 so as to be aligned in an axial direction. The at least three land portions 54 include a shoulder land portion 54s. The plurality of circumferential main grooves 52 include a shoulder circumferential main groove 52s. A circumferential narrow groove 50 is formed on the shoulder land portion 54s so as to continuously extend in a circumferential direction. A groove width of the circumferential narrow groove 50 is smaller than a groove width of the shoulder circumferential main groove 52s. The circumferential narrow groove 50 is located between the shoulder circumferential main groove 52s and an end 36e of the outer layer 36. The circumferential narrow groove 50 is tapered.