Multi-layer Tyre Crown Segmentation for Mass Reduction
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Solution Overview
Problem
Heavy-duty tires face challenges in maintaining endurance and wear performance under varying road conditions while reducing mass and manufacturing costs, and they experience increased rolling resistance, leading to higher fuel consumption.
Innovation Solution
A tire design with a radial carcass reinforcement featuring at least three working crown layers of reinforcing elements crossed at angles between 10° and 45°, 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 using specific rubber mixtures with lower elastic moduli to enhance cohesion and reduce rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the thickness and diameter of reinforcing elements are reduced to decrease tire mass, then rolling resistance improves and fuel consumption decreases, but the strength and endurance of the crown reinforcement may deteriorate
Solution Approach 1:
The crown reinforcement is divided into multiple working layers (at least three) with different orientations. Each layer uses thinner individual wires (diameter < 0.50 mm) spaced closely together (distance < 1 mm), distributing the reinforcement function across multiple segments rather than relying on a single thick layer, thereby maintaining strength while reducing mass.
Solution Approach 2:
The patent combines multiple materials with different properties: thin metal wires for reinforcement, rubber mixtures with specific elastic moduli for cohesion and stress distribution. This composite structure allows the use of lighter individual components while achieving the required overall strength through material synergies.
2Reliability
If layers of rubber mixture are added between working top layers to distribute shear stresses and improve endurance, then tire mass increases and manufacturing costs increase
Solution Approach 1:
The patent specifies precise parameter ranges for the rubber mixture layers, including elastic modulus (tan δ max < 0.100) and thickness constraints. By optimizing these parameters, the rubber layers provide necessary stress distribution and cohesion with minimal mass addition, achieving improved endurance without excessive weight gain.
3Reliability
If multiple working crown layers are used to improve endurance and wear performance, then the complexity of the crown reinforcement structure increases and manufacturing becomes more difficult
Solution Approach 1:
The crown reinforcement is segmented into multiple working layers with distinct functions and orientations. Each layer contributes specifically to wear resistance or structural integrity, allowing the complex performance requirements to be divided into manageable structural components that can be manufactured and assembled systematically.
4Strength
If the distance between reinforcing elements is reduced to increase than if the distance between reinforcing elements is reduced to increase circumferential rigidity, then the manufacturing precision requirements increase and production becomes more difficult
Solution Approach 1:
The patent defines specific parameter ranges for wire spacing (distance < 1 mm along the normal to the average line) and orientation angles (10°-45°). These quantified parameters provide clear manufacturing targets that balance the need for high circumferential rigidity with achievable production tolerances, enabling precise construction without excessive complexity.
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 rolling resistance, and increased circumferential rigidity, leading to lower fuel consumption and reduced wear inhomogeneities.
Implementation Method 1
at least two layers of rubber mixture C1 being arranged between the ends of said at least three layers of working top, in a meridian plane
Implementation Method 2
the modulus of elasticity under tension at 10% elongation of at least one layer Ci of rubbery mixture is less than 8 MPa and the maximum value of tan(δ), denoted tan(δ) max, of said at least one layer Ci is less than 0.100
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 of reinforcing elements, at least two rubber blend layers Ci being disposed between the ends of the working layers. According to the invention, the thickness of the working layers, measured in the equatorial plane, is less than 5 mm, the reinforcing elements thereof being 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 working 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 less than 8 MPa; and the maximum tan(δ) value is less than 0.100.