Tire Sub-Layer Segmentation for Rolling Resistance and Cornering Stiffness
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Solution Overview
Problem
Current tyre designs face a trade-off between dynamic drift thrust response and rolling resistance, where improving one parameter often worsens the other, particularly due to the limitations in the stiffness of sub-layer materials used in tyres for passenger vehicles.
Innovation Solution
A tyre design featuring a sub-layer with three distinct rubber compounds, including a first base layer, a second base layer with lower dynamic shear modulus, and a covering layer with higher stiffness, strategically positioned to optimize cornering stiffness and rolling resistance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If sub-layer material with low dynamic shear modulus is used to reduce rolling resistance, then rolling resistance is improved, but cornering stiffness deteriorates
Solution Approach 1:
The sub-layer is divided into three distinct base layers with different rubber compounds, each having different dynamic shear moduli. This segmentation allows different regions of the sub-layer to perform different functions: some regions provide low stiffness for reduced rolling resistance, while other regions provide higher stiffness for maintained cornering performance
Solution Approach 2:
Different portions of the sub-layer are assigned different material properties (dynamic shear moduli) based on their specific functional requirements. The first, second, and third base layers have progressively different stiffness characteristics, creating local quality variations that optimize both rolling resistance and cornering stiffness in their respective regions
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 significant improvement in rolling resistance while maintaining acceptable cornering stiffness, enhancing the overall performance compromise for passenger vehicles by reconciling the need for better dynamic response and reduced energy consumption.
Implementation Method 1
the dynamic shear modulus G* and the tg δ (tangent delta) value thereof, are lower than the values of the same parameters of the sub-layer material in contact with the tread material
Implementation Method 2
a first base layer made up of a rubber compound of given stiffness A, a second base layer made up of a rubber compound of given stiffness B, a third base layer made up of a rubber compound of given stiffness C
Data Source
AI summary
A tire has a sub-layer (7) made up substantially of a first base layer (71) disposed radially on the crown reinforcement (5) and axially between the median plane (CP) and a transition edge (711), the transition edge (711) being situated axially between the median plane (CP) and a shoulder (60), said first base layer (71) being made up of a rubber compound of given stiffness A, a second base layer (72) disposed radially on the crown reinforcement (5) and axially between the transition edge (711) and a shoulder end (721), said second base layer (72) being made up of a rubber compound of given stiffness B, a covering layer (73) disposed radially on the first base layer (71) and on the second base layer (72) and radially on the inside of the tread (6) and axially at least in sections situated between the median plane (CP) and the shoulder end (721), said covering layer (73) being made up of a rubber compound of given stiffness C, the stiffness B being less than the stiffness A, which is less than the stiffness C, and the stiffness C being greater than the stiffness M.