Heavy-Duty Radial Tire Hooping Layer for Shoulder Crack Resistance
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Solution Overview
Problem
Heavy-duty radial tires for civil engineering and agricultural vehicles face challenges in reducing the risk of cracking of rubber compounds at the ends of working layers and rupture of radially external hooping layers during rolling, due to high mechanical stresses and inadequate elastic properties, especially at the shoulders where deformation is significant.
Innovation Solution
Incorporating a hyperelastic radially outer hooping layer with specific geometric characteristics, such as hyperelastic cables wound in a helix with defined diameters and curvature, to provide enhanced tensile elasticity and buckling resistance, reducing shearing stresses and improving resistance to compressive deformations, while maintaining structural integrity and minimizing material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard hooping layers are used in the crown reinforcement, then the tire structure is simpler and material usage is reduced, but the risk of cracking in rubber compounds and rupture of reinforcing elements increases during rolling
Solution Approach 1:
The patent applies parameter changes by specifying precise geometric characteristics of the hyperelastic cables (helix diameter Dh between 0.40-1.60mm, wire element diameter Df between 0.10-0.50mm, arch diameter Dv ≥ 0.46mm, helix curvature radius Rf between 2-7mm, and pitch-to-diameter ratio K between 19-44). These parameter optimizations enable the hooping layer to achieve superior elastic properties and buckling resistance, effectively reducing cracking and rupture risks while maintaining a relatively simple single-layer structure
Solution Approach 2:
The patent employs composite materials by combining hyperelastic metal reinforcements (cables with specific helical wire element structures) with rubber compounds. This composite construction provides enhanced tensile elasticity and buckling resistance, allowing the hooping layer to withstand high mechanical stresses during rolling without cracking or rupturing, thereby improving reliability
2Strength
If hyperelastic cables with specific geometric characteristics are used, then tensile elasticity and buckling resistance are enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific parameter ranges for the hyperelastic cables (Dh, Df, Dv, Rf, K, helix angle α) that balance manufacturing feasibility with performance requirements. These optimized parameter ranges enable the cables to achieve enhanced tensile elasticity and buckling resistance while remaining manufacturable with standard precision capabilities
Solution Approach 2:
The patent applies local quality by specifying different geometric characteristics for different parts of the cable structure (e.g., wire element diameter, helix diameter, arch diameter, curvature radius). This localized optimization of geometric parameters allows each component to contribute maximally to the overall strength and elasticity while maintaining manufacturing practicality
3Strength
If the hooping layer extends beyond the working layer ends, then resistance to compressive deformations at shoulders is improved, but the material mass increases
Solution Approach 1:
The patent optimizes the axial width and radial position of the hooping layer to achieve minimal extension beyond the working layer ends. This parameter optimization provides sufficient resistance to compressive deformations at the shoulders while minimizing additional material usage and tire mass
Solution Approach 2:
The patent applies local quality by positioning the radially outer hyperelastic hooping layer specifically at regions subject to high compressive stresses (near the ends of working layers and at shoulders). This localized placement ensures enhanced resistance where needed while avoiding unnecessary material in other areas, thereby minimizing overall mass increase
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 solution effectively reduces the risk of cracking in rubber compounds and rupture of reinforcing elements, enhancing the tire's endurance and mileage performance by up to 15% compared to standard designs, while maintaining performance and reducing material mass.
Implementation Method 1
hyperelastic metal reinforcements, parallel to each other and forming, with a circumferential direction (XX'), of the tire, an angle at most equal to 5°, each hyperelastic metal reinforcement comprising at least one cable, called hyperelastic
Implementation Method 2
each metal wire element describing, when the cable extends in a substantially rectilinear direction, a helix-shaped trajectory around a main axis (A) substantially parallel to the substantially rectilinear direction
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a radial tire (1) for a heavy vehicle, in which, on either side of the equatorial plane, a hyperelastic reinforcement ply (323), which is arranged radially outwards of the working layers, covers the axial end of the working layer with the smaller axial width (322), the axial ends of which are at a minimum axial distance (Ds/2) from said end, containing hyperelastic cords (50). Said cords comprise filamentary elements (54) on a single layer (52). The distance between the center of each filamentary element (54) of the layer (52) and the main axis (A) of the cord is equal to half of the helix diameter Dh and is substantially constant and equal for all the metal filamentary elements (54) of the layer (52), the metal filamentary elements (54) defining an internal arch (58) of the cord, having the diameter Dv. Each metal filamentary element (54) has a diameter Df and a helix radius of curvature Rf, such that: 9 ≤ Rf / Df ≤ 30, and 1.30 ≤ Dv / Df ≤ 4.5. Said hyperelastic cords are embedded in a rubber compound.