Tire Tread with Dual Elastomeric Layers for Wear and Heat Management
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Solution Overview
Problem
Heavy-duty tires face challenges in endurance and retreadability due to excessive wear and temperature-related issues, particularly shear stresses and cracking at the ends of reinforcement layers, which limit their rolling distance before needing retreading.
Innovation Solution
A tire design with a radial carcass reinforcement featuring a tread composed of two layers of polymeric mixtures, where the outer layer has a high macro dispersion Z rating and low tan(δ)max, and the inner layer has high elongation at break, optimizing wear resistance and temperature management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single protective layer with reinforcing elements oriented in the same direction is used, then the manufacturing process is simple, but the tire exhibits minimal resistance to transverse compression forces and shows excessive wear at the ends of reinforcing elements
Solution Approach 1:
The protective layer is divided into two distinct layers: a first protective layer with reinforcing elements at a first angle, and a second protective layer with reinforcing elements at a second angle different from the first. This segmentation allows each layer to resist different directional forces, with the layers working together to provide comprehensive protection against transverse compression forces while reducing wear at reinforcing element ends.
2Productivity
If the tread is made of polymeric materials with high wear resistance, then the tire can travel longer distances, but the operating temperature increases excessively causing rubber cracks at the ends of reinforcement layers
Solution Approach 1:
The patent modifies the angular parameters of the reinforcing elements in the two protective layers. By setting the first protective layer at a first angle and the second protective layer at a second angle, the distribution of stresses is optimized to reduce concentration at the ends of reinforcing elements. This parameter change allows the use of high-wear-resistance polymeric materials while controlling operating temperature and preventing rubber cracks.
3Ease of manufacture
If reinforcing elements are oriented at the same angle in both protective layers, then the manufacturing process is simplified, but the tire shows excessive wear and reduced endurance at the ends of the axially shortest top layer
Solution Approach 1:
The protective reinforcement is segmented into two layers with different angular orientations. The first protective layer has reinforcing elements at a first angle, while the second protective layer has reinforcing elements at a second angle. This segmentation creates a more durable crown reinforcement structure that distributes stresses more evenly, preventing excessive wear and extending the endurance of the axially shortest top layer.
Solution Approach 2:
The two protective layers with different angular orientations form a composite reinforcement structure. This composite configuration combines the advantages of different angular arrangements, creating a crown reinforcement that exhibits minimal deformation under various stresses and maintains high endurance while remaining manufacturable.
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 enhances the tire's rolling distance before retreading by balancing wear resistance and temperature control, while maintaining resistance to attacks and reducing rolling resistance, thus extending the tire's lifespan and usability.
Implementation Method 1
the materials used in the tread are advantageously chosen with hysteresis losses adapted to the operating conditions of the tire
Implementation Method 2
a second layer of elastomeric mixture, radially inner to said first layer of elastomeric mixture, having an elongation at break at 60°C greater than 600%
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a tire, with radial carcass reinforcement, comprising a crown reinforcement itself capped radially by a tread connected to two beads by two side walls, said tread comprising at least two layers of polymer compound which are radially superposed. According to the invention, a first layer of filled elastomeric compound constituting the radially outer part of the tread has a macro dispersion score Z higher than 80 and a maximum tan(δ), value denoted tan(δ) max, lower than 0.130 and a second layer of elastomeric compound radially on the inside of said first layer of polymer compound has an elongation at break at 60°C which is higher than 600%.