Multi-Compound Tire Tread for Wet Grip and Low Rolling Resistance
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Solution Overview
Problem
Passenger vehicle tires face a decline in grip and aquaplaning performance as they wear down, and existing solutions to improve wet grip often compromise rolling resistance or require complex and costly tread patterns.
Innovation Solution
A passenger vehicle tire design featuring a tread composed of three rubber compounds, where the central part consists of two compounds providing excellent grip and wear resistance, and the outer parts include a third compound with reduced hysteresis to minimize rolling resistance, ensuring consistent performance throughout the tire's life without complex tread patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rubber compound with high hysteresis at 0°C is used to improve wet grip, then grip on wet ground and aquaplaning performance are improved, but rolling resistance degrades because the same compound has high hysteresis at 23°C
Solution Approach 1:
The tread is divided into multiple zones (central part and axially outer parts) with different rubber compound compositions. The central part uses compounds optimized for wet grip while the outer parts use compounds with different properties, allowing each zone to perform its specific function without compromising overall performance
Solution Approach 2:
Different rubber compounds are applied to different regions of the tread based on their specific performance requirements. The central part receives compounds with high hysteresis at 0°C for wet grip, while the axially outer parts receive compounds with reduced hysteresis at 23°C to minimize rolling resistance, creating local optimization throughout the tread structure
2Loss of energy
If the tread pattern height decreases with wear, then rolling resistance decreases, but aquaplaning performance and water storage capacity deteriorate
Solution Approach 1:
The tread is designed with multiple rubber compounds that provide different properties at different stages of wear. As the tread wears and pattern height decreases, the underlying compounds with appropriate hysteresis characteristics become more exposed, maintaining aquaplaning performance and water storage capacity throughout the tire's service life
Solution Approach 2:
The invention changes the physical and chemical parameters of the rubber compounds used in different tread zones. By selecting compounds with specific hysteresis characteristics at different temperatures and wear stages, the tread maintains optimal performance parameters for both rolling resistance and aquaplaning resistance throughout its service life
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 maintains superior grip and aquaplaning performance at the end of its life while keeping rolling resistance comparable to new tires, with a balanced wear pattern and reduced energy dissipation, thus enhancing overall tire performance.
Implementation Method 1
The overpressures on the ground that the cuts generate at the interface between the tread surface and said walls make it possible to break the film of water that is present on the ground on which the tyre is running in order to bring into contact said ground and the rubber compound of the tread
Data Source
AI summary
A tire for a vehicle comprises a tread (2), of which the central part of the tread (2) comprises at least two rubber compounds (221, 222), making up at least 90% of its volume. The first compound (221) is radially on the outside of the second compound (222) and makes up at least 40% and at most 60% of the volume of the central part. The second rubber compound (222) has a Shore hardness DS2 at least equal to 5 plus the Shore hardness DS1 of the first compound (221) and dynamic losses at a temperature of 0° C. and 23° C. that are at least equal to those of the first rubber compound (221). The axially outer parts of the tread are made up of a third compound (223) capable of touching the ground, having a stiffness and a hysteresis that are lower than those of the first compound.