Tire Tread Sub-Layer Reinforcement for Low Rolling Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current tyre designs face challenges in achieving a balance between excellent grip, low rolling resistance, and low wear while maintaining acceptable noise levels, particularly in sports vehicles, as they often compromise on cornering stiffness and rolling resistance when using low-stiffness rubber tread compounds.
Innovation Solution
The tyre features a tread with a sub-layer and reinforcing elements made of specific rubber compounds with varying stiffnesses, where the sub-layer is flush with the furrow bottoms and the reinforcing elements extend radially, providing a dynamic shear modulus gradient to enhance cornering stiffness without increasing rolling resistance or noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If low-stiffness rubber compounds are used in the tread, then rolling resistance is reduced and energy efficiency is improved, but cornering stiffness deteriorates
Solution Approach 1:
The tyre is divided into distinct functional zones: a tread made of low-stiffness rubber for low rolling resistance, and reinforcing elements made of high-stiffness rubber for cornering support. This segmentation allows each zone to optimize its specific function without compromising the other.
Solution Approach 2:
Different rubber compounds with different stiffness properties are applied to specific locations within the tread structure. The low-stiffness compound is used in the main tread contact area to reduce rolling resistance, while high-stiffness reinforcing elements are strategically placed in regions that contribute to cornering stiffness but do not contact the road.
2Strength
If high-stiffness materials are used in the sub-layer, then cornering stiffness is improved, but rolling resistance increases
Solution Approach 1:
The sub-layer is segmented into a base sub-layer made of low-stiffness material for low rolling resistance, and discrete high-stiffness reinforcing elements embedded within it. This allows the high-stiffness material to provide cornering support only where structurally necessary, rather than throughout the entire sub-layer.
Solution Approach 2:
The tyre structure uses a composite arrangement of rubber compounds with different stiffness properties. The combination of low-stiffness base material and high-stiffness reinforcing elements creates a composite structure that achieves both low rolling resistance and adequate cornering stiffness.
3Strength
If the sub-layer material stiffness is increased, then tread stiffening in shear is improved, but the ability to counter tread flattening in the contact patch deteriorates
Solution Approach 1:
High-stiffness reinforcing elements are placed locally within the sub-layer at positions that provide shear resistance without interfering with the natural flattening of the tread in the contact patch. This localized reinforcement maintains tread compliance where needed while providing stiffness where required.
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
This design significantly improves cornering stiffness while maintaining a slight improvement in rolling resistance, achieving a better performance balance and reducing hysteresis losses, thus preserving energy and material resources.
Implementation Method 1
reducing hysteresis losses
Data Source
AI summary
A tire having an axis of rotation and a median plane (CP) perpendicular to the axis of rotation, and comprising: a crown reinforcement, a tread positioned radially on the outside of the crown reinforcement and axially between two shoulders, comprising a contact face intended to come into contact with the roadway while the tire is being driven on, wherein the tread is primarily made up of at least one rubber compound of given dynamic shear modulus M and comprises a plurality of furrows oriented substantially circumferentially, each furrow having a furrow bottom, and a sub-layer disposed radially on the outside of the crown reinforcement and radially on the inside of the tread, wherein the sub-layer is made up of at least one rubber compound of given dynamic shear modulus A is flush with each furrow bottom.