Tyre Tread Segmentation for Wet Grip and Wear Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current tyres fail to maintain wet performance and steering stability as the tread portion wears, particularly in environmental and automatic vehicle driving contexts where maintenance-free tyres are required.
Innovation Solution
A tyre design featuring a tread portion with a first cap rubber layer and a second cap rubber layer, where the loss tangent of the second cap rubber layer is greater than the first, combined with a base rubber layer, and a plurality of sipes that extend inwardly from the ground contact surface, maintaining wet grip and steering stability even as the tread wears.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tread portion is made with uniform rubber composition, then manufacturing is simple, but wet performance and steering stability deteriorate as the tread wears
Solution Approach 1:
The tread portion is divided into multiple cap rubber layers (first cap rubber layer with lower loss tangent and second cap rubber layer with higher loss tangent) and a base rubber layer, each with different rubber compositions and loss tangent values. This segmentation allows different regions of the tread to have optimized properties for their specific functions, maintaining wet performance and steering stability as the tread wears.
Solution Approach 2:
Different cap rubber layers are assigned different loss tangent values and rubber compositions tailored to their specific locations and functions. The first cap rubber layer has lower loss tangent for reduced heat generation, while the second cap rubber layer has higher loss tangent for enhanced wet grip. This local optimization ensures that each region contributes to overall performance maintenance during wear.
2Loss of energy
If low loss tangent rubber is used throughout the tread, then heat generation is reduced, but wet performance deteriorates
Solution Approach 1:
The tread is segmented into cap rubber layers with different loss tangent characteristics. The first cap rubber layer uses low loss tangent rubber to minimize heat generation, while the second cap rubber layer uses high loss tangent rubber to maximize wet grip performance. This segmentation resolves the contradiction by assigning opposite loss tangent requirements to different functional regions.
Solution Approach 2:
Different loss tangent values are applied locally in different cap rubber layers based on their specific functions. The first cap rubber layer prioritizes heat reduction with low loss tangent, while the second cap rubber layer prioritizes wet grip with high loss tangent, achieving both objectives simultaneously.
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 effectively maintains wet performance and steering stability throughout the wear life of the tread, delaying the progression of wear and ensuring consistent performance on wet roads.
Implementation Method 1
a first cap rubber layer forming a ground contact surface and having a loss tangent tan δ1, and a second cap rubber layer disposed inwardly in a tyre radial direction of the first cap rubber layer and having a loss tangent tan δ2
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A tyre includes a tread portion 2 including a first cap rubber layer 11 forming a ground contact surface 2s and having a loss tangent tan δ1, and a second cap rubber layer 12 disposed inwardly in a tyre radial direction of the first cap rubber layer 11 and having a loss tangent tan δ2, the loss tangent tan δ2 being greater than the loss tangent tan δ1. The tread portion 2 is provided with a plurality of sipes 15 opening to the ground contact surface 2s. The plurality of sipes 15, at least partially, extends inwardly in a tyre radial direction from the ground contact surface 2s to a location beyond a boundary16 between the first cap rubber layer 11 and the second cap rubber layer 12, and a maximum length L2 of the plurality of sipes 15 in the second cap rubber layer 12 is smaller than a length L1 of the plurality of sipes 15 at the ground contact surface2s.