Thermally Adaptive Tyre Underlayer for Grip and Road Wear Control
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Solution Overview
Problem
Traditional winter tires face challenges such as reduced durability, increased rolling resistance, and excessive road wear due to softer tread layers, which are not optimally suited for fluctuating weather conditions, especially around the freezing point of water, leading to suboptimal grip and wear resistance.
Innovation Solution
A pneumatic tire with a thermally adaptive underlayer composed of a polymer system with low miscibility elastomers, such as natural rubber and solution-polymerized styrene-butadiene rubber, which adjusts its dynamic stiffness in response to temperature changes, enhancing grip and durability by modifying the behavior of tread elements and stud protrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a softer tread layer rubber composition is used to improve grip on cold and frozen surfaces, then winter grip properties are improved, but tread durability decreases and rolling resistance increases
Solution Approach 1:
The tyre is divided into functionally distinct layers: a harder tread layer for durability and a softer thermally adaptive underlayer for grip. This segmentation allows each layer to optimize its properties independently, resolving the contradiction between grip and durability.
Solution Approach 2:
Different regions of the tyre have different rubber compositions tailored to their specific functions. The underlayer contains softer rubber compounds with lower glass transition temperatures to provide flexibility and grip in cold conditions, while the tread layer uses harder compounds for wear resistance.
2Reliability
If a softer tread layer rubber composition is used to improve grip on cold surfaces, then winter grip properties are improved, but rolling resistance increases leading to higher fuel consumption
Solution Approach 1:
The tyre structure separates the grip function (underlayer) from the durability function (tread layer). The underlayer's softer composition improves grip without significantly increasing overall rolling resistance, as the harder tread layer dominates the rolling resistance characteristics.
3Reliability
If studs are embedded in the tread to penetrate ice and snow for improved grip, then winter grip on frozen surfaces is improved, but road wear increases due to abrasion of dry pavement
Solution Approach 1:
The thermally adaptive underlayer acts as an intermediary between the stud and the road surface. It provides a compliant mounting base for studs while reducing their direct impact on the road, thereby minimizing road wear while maintaining stud effectiveness on ice and snow.
4Ease of operation
If a single tyre composition is used to cover all weather conditions, then ease of operation is improved, but performance adaptability to fluctuating temperatures decreases
Solution Approach 1:
The underlayer uses thermally adaptive rubber compounds whose physical properties change dynamically with temperature. As temperature fluctuates, the underlayer's glass transition behavior automatically adjusts its flexibility and grip characteristics, providing adaptive performance without requiring manual intervention.
Solution Approach 2:
The rubber composition parameters of the underlayer are specifically designed to change with temperature. By selecting elastomers with appropriate glass transition temperatures, the underlayer transitions between different mechanical states in response to temperature changes, optimizing performance across varying conditions.
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 thermally adaptive underlayer improves handling and winter grip by maintaining low dynamic stiffness on warmer temperatures and increasing it on colder temperatures, reducing energy dissipation and extending tire life while minimizing road wear.
Implementation Method 1
the polymer system, the glass transition temperatures of the elastomers are sufficiently far apart from each other. Thereby a pneumatic tyre comprising self-adjustable performance characteristics is obtainable, wherein the dynamic stiffness E* of the thermally adaptive underlayer is highly dependent of the temperature experienced by said layer in the vicinity of the freezing point of water
Implementation Method 2
To reduce the energy dissipation, polymers producing less hysteresis may be selected. Hysteresis is a measure of the amount of energy lost per cycle during deformation of an elastomer
Data Source
Figure 1a~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a pneumatic tyre, which contains a structure wherein a thermally adaptive underlayer is positioned beneath a tread layer, wherein the thermally adaptive underlayer is based on a polymer system that has been selected to contain elastomers with distinct glass transition temperatures sufficiently far apart from each other and which exhibit low miscibility towards each other. Due to the tyre construction and the thermally adaptive underlayer, while driving a vehicle, the performance characteristics of the pneumatic tyre are configured to adapt to the driving conditions on the road based on the temperature experienced by the thermally adaptive underlayer. This is of particular relevance during colder seasons, such as for a winter tyre, wherein the thermally adaptive underlayer may be used to design an improved tread layer and for a studded pneumatic tyre, wherein the composition and thickness of the thermally adaptive underlayer may be used to control the dynamic impact of the stud on a driving surface, when the tyre is in motion.