Tyre Crown Ply With Individual Wires for Mass Reduction
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Solution Overview
Problem
Current heavy-duty tires face challenges in maintaining endurance and wear performance under varying conditions while minimizing mass and manufacturing costs, with existing solutions often resulting in increased tire weight and costs due to additional reinforcing layers.
Innovation Solution
A tire design featuring a radial carcass reinforcement with at least three working crown layers of reinforcing elements, each making angles between 10° and 45° with the circumferential direction, covered radially with a tread and separated by layers of rubber mixture to distribute shear stresses, reducing the thickness and diameter of reinforcing elements, and maintaining circumferential rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional reinforcing layers are added to improve endurance and wear performance, then the tire's durability is improved, but the tire mass and manufacturing costs increase
Solution Approach 1:
The patent changes the physical parameters of the reinforcing elements by using unitary metal wires with diameter less than 0.50 mm (reducing from conventional larger diameters) and arranging them at specific angles (10° to 45° with circumferential direction). These parameter changes allow achieving the required reinforcement with thinner, lighter elements while maintaining or improving durability performance.
Solution Approach 2:
The patent applies different configurations of reinforcing elements at different locations. The unitary metal wires are arranged with specific spacing (distance strictly less than 1 mm) and angles that vary by layer, creating locally optimized reinforcement patterns that provide adequate strength without uniformly increasing mass throughout the entire tire structure.
2Weight of moving object
If the thickness and diameter of reinforcing elements are reduced to decrease tire mass, then the tire weight is reduced, but the circumferential rigidity may be compromised
Solution Approach 1:
The patent segments the crown reinforcement into at least three distinct working layers, each with unitary metal wires oriented at specific angles. This segmentation allows each layer to contribute to circumferential rigidity in a coordinated manner, where the combined effect of multiple thin layers with optimized angular orientations provides equivalent or superior rigidity to conventional single thick layers, while reducing overall mass.
Solution Approach 2:
The patent creates a composite structure by combining multiple layers of unitary metal wires with rubber mixture layers. The metal wires provide tensile strength and rigidity, while the rubber layers provide flexibility and stress distribution. This composite approach allows using thinner metal elements (diameter < 0.50 mm) while maintaining overall structural rigidity through the synergistic combination of materials and layers.
3Strength
If conventional thick reinforcing elements are used to ensure structural strength, then the tire's strength is maintained, but the manufacturing complexity and storage difficulty increase
Solution Approach 1:
The patent changes the dimensional parameters of reinforcing elements from conventional thick cables to thin unitary metal wires with diameter less than 0.50 mm. These thinner wires are more flexible and easier to handle during manufacturing, allowing simpler placement and arrangement in the tire structure. The reduced diameter also facilitates storage and transportation of the reinforcing materials before assembly.
Solution Approach 2:
By dividing the crown reinforcement into multiple layers of thin unitary metal wires rather than using fewer thick elements, the patent creates a structure that is easier to manufacture. The thin wires can be more easily positioned at precise angles and spacings, and the layered structure allows for modular assembly, reducing manufacturing complexity compared to handling and positioning fewer, heavier reinforcing elements.
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 design achieves equivalent endurance and wear performance with reduced tire mass and manufacturing costs, improved circumferential rigidity, and simplified production and storage of rubber mixture layers, while minimizing the risk of crack initiation and propagation.
Implementation Method 1
at least two layers of rubber mixture Ci being arranged between the ends of said at least three layers of working top, in a meridian plane... to distribute shear stresses
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, at least two rubber blend layers Ci being disposed between the ends of the layers. According to the invention, in a meridian plane, the thickness of the working crown layers, measured in the equatorial plane, is less than 5 mm; the reinforcing elements of these layers are individual metal wires having a diameter of less than 0.50 mm; the distance between the reinforcing elements is strictly less than 1 mm; the axial width of each of the working crown layers is greater than 60% of the axial width of the tread; at least a distance di between two working layers separated by a rubber blend layer Ci, measured at the end of the axially narrowest working layer on contact, is such that 0.5 < di < 2.5 mm; and the thickness of at least one rubber blend layer Ci is substantially constant across the axial width between the axially inner end of a rubber blend layer Ci and the end of the axially narrowest working layer on contact.