Heavy-Duty Tyre Crown Reinforcement with Individual Wires
Solution Overview
Problem
Current heavy-duty tires face challenges in maintaining endurance and wear performance under varying road conditions, with increased rolling resistance leading to higher fuel consumption, and existing solutions often result in increased tire mass and manufacturing costs.
Innovation Solution
A tire design with a radial carcass reinforcement featuring at least three working crown layers of unitary metal wires, each with a specific thickness and spacing, covered by rubber mixture layers that decouple shear stresses, reducing the diameter of reinforcing elements and overall tire thickness while maintaining circumferential rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the crown reinforcement is strengthened to improve endurance and wear performance under heavy loads and high temperatures, then the tire mass increases, but this leads to increased rolling resistance and higher fuel consumption
Solution Approach 1:
The patent changes the geometric parameters of the crown reinforcement by reducing the diameter of reinforcing elements from conventional sizes to specifically 6-12 mm, and reduces the number of layers from 4-6 to 2-3 layers. This parameter optimization maintains the required mechanical strength while reducing the overall mass of the tire, thereby lowering rolling resistance and fuel consumption without compromising endurance and wear performance
Solution Approach 2:
The patent employs composite material structures by combining different types of reinforcing elements (metal cables, metal wires, synthetic fibers) with rubber compounds of specific properties. The use of composite calendering layers with controlled thickness (0.5-2.0 mm) and specific rubber composition creates a synergistic effect that provides both structural strength and flexibility, achieving high reliability with reduced mass
2Weight of moving object
If the diameter of reinforcing elements is reduced to decrease tire mass, then the rolling resistance improves, but the circumferential rigidity may be compromised
Solution Approach 1:
The patent segments the crown reinforcement into multiple discrete layers (2-3 layers) with specific angular orientations (10°-45° to the circumferential direction). This segmentation allows each layer to contribute to circumferential rigidity through its specific orientation, while the overall structure remains lightweight. The spaced arrangement of layers with controlled calendering thickness between them creates an efficient load distribution system that maintains rigidity without requiring excessive material
Solution Approach 2:
The patent optimizes the spatial arrangement of reinforcing elements by controlling the angular orientation of each layer relative to the circumferential direction (10°-45° range). This dimensional optimization in the angular domain allows the structure to achieve maximum circumferential rigidity with minimal material. The specific positioning and orientation of 2-3 layers create a three-dimensional load-bearing structure that efficiently resists circumferential stresses while minimizing mass
3Ease of manufacture
If the number of crown reinforcement layers is reduced to lower manufacturing costs, then the manufacturing complexity decreases, but the wear performance may deteriorate
Solution Approach 1:
The patent optimizes the number of crown reinforcement layers to 2-3 layers, reducing from the conventional 4-6 layers. This parameter change simplifies the manufacturing process and reduces costs while maintaining wear performance through careful selection of rubber compound properties (modulus >9 MPa, tan δ <0.100) and precise control of layer thickness (0.5-2.0 mm calendering), ensuring each layer contributes maximally to wear resistance
Solution Approach 2:
The patent applies local quality optimization by specifying different properties for different components: the rubber compounds in calendering layers have specific modulus and tan δ values tailored to provide both flexibility and wear resistance, while the reinforcing elements (6-12 mm diameter cables and wires) are positioned and oriented to provide localized strength where needed. This targeted optimization ensures high wear performance with fewer layers
Data Source
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AI summary
The invention relates to a tyre comprising a crown ply formed by at least three working crown layers (41, 42, 43) of reinforcing elements, at least two rubber blend layers Ci being disposed between the ends of the at least three working crown layers. According to the invention, in a meridian plane, the thickness of the at least three working crown layers, measured in the equatorial plane, is less than 5 mm; the reinforcing elements of the at least three working crown layers are individual metal wires having a diameter of less than 0.50 mm; the distance between the reinforcing elements, measured along the normal to the direction of the centre line of the wire, is strictly less than 1 mm; the axial width of each of the at least three working crown layers is greater than 60% of the axial width of the tread; the tensile modulus of elasticity at 10% elongation of at least one layer Ci is greater than 9 MPa; and the maximum tan(δ) value, denoted tan(δ)max, of the at least one layer Ci is less than 0.100.