Three-Layer Tyre Crown for Endurance and Wear
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Solution Overview
Problem
Heavy-duty tires face challenges in endurance and wear performance, particularly when driving on stony ground and at high speeds, due to shear stresses and increased operating temperatures, which lead to cracks and uneven tread wear, and existing solutions increase tire mass and manufacturing costs.
Innovation Solution
A tire design with a radial carcass reinforcement featuring three working crown layers with specific angle orientations and widths, along with a protective layer, to distribute stresses and reduce compression, while using cables with varying diameters and wire configurations to optimize triangulation and reduce mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the top reinforcement is increased to improve endurance under high temperatures, then the endurance potential increases, but shear stresses between top layers cause cracks and propagation in the rubber
Solution Approach 1:
The top reinforcement is divided into three separate working layers instead of one or two layers. This segmentation distributes the shear stresses across multiple interfaces rather than concentrating them at single layer boundaries, reducing the likelihood of crack initiation and propagation in the rubber between layers.
Solution Approach 2:
The patent uses a composite structure with three layers of reinforcing elements oriented at different angles (first layer: 15-30°, second layer: 30-45°, third layer: 45-60° relative to circumferential direction). This composite arrangement optimizes stress distribution by having each layer handle different stress components, improving overall endurance while maintaining rubber integrity.
2Reliability
If additional reinforcing elements are added to improve endurance, then the endurance performance increases, but the tire mass and manufacturing costs increase
Solution Approach 1:
The patent optimizes the angular parameters of the three working layers (15-30°, 30-45°, 45-60°) to achieve maximum endurance performance with minimal material. By carefully selecting these angles, the structure efficiently distributes stresses, allowing the use of fewer and lighter reinforcing elements compared to conventional designs with fewer layers at suboptimal angles.
Solution Approach 2:
Each of the three working layers is assigned a specific angular orientation optimized for its position in the structure. The first layer (15-30°) handles specific stress patterns, the second layer (30-45°) handles intermediate stresses, and the third layer (45-60°) handles outer layer stresses. This local optimization allows each layer to be as thin and light as possible while still performing its specific function.
3Duration of action of stationary object
If the tire is designed for high-speed driving on motorways, then the wear is reduced and lifespan increases, but the operating temperatures increase requiring proportional increase in endurance potential
Solution Approach 1:
The three-layer working structure segments the thermal and mechanical stresses generated during high-speed operation. Each layer acts as a thermal and stress buffer, preventing heat concentration at single layer interfaces. This segmentation allows the tire to withstand higher operating temperatures without compromising the rubber or reinforcing elements, enabling extended lifespan under high-speed conditions.
Data Source
AI summary
The invention relates to a tyre that comprises a crown reinforcement made up of three working crown layers of reinforcing elements. According to the invention, the reinforcing elements of the two radially outermost working layers (42, 43) are crossed from one layer to the next making with the circumferential direction angles of between 20 and 45°, the angles formed with the circumferential direction by the reinforcing elements of the radially innermost working layer (41) being comprised between 15 and 20°, the reinforcing elements of the two radially innermost working layers (41, 42) being oriented in the same direction, the ratio of the difference between the angles of the reinforcing elements of the two radially innermost working layers to the angle of the reinforcing elements of the radially innermost working layer being strictly less than 0.65, the mean value between the mean angle of the reinforcing elements of the two radially innermost working layers and the angle of the reinforcing elements of the third working layer being less than or equal to 22°, the widths (L42, L43) of the two radially outermost working layers (42, 43) being greater than 0.7 times the width of the tread (L5), and the width (L41) of the radially innermost working layer (41) being strictly less than 0.7 times the width (B) of the tread.