Heavy Vehicle Tyre Crown Reinforcement with Variable Pitch Circumferential Elements
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Solution Overview
Problem
Heavy-duty tires face challenges in maintaining endurance and wear resistance, especially under severe conditions, due to shear stresses and temperature-related issues in the crown reinforcement area, leading to premature wear and cracking.
Innovation Solution
A tire design with a radial carcass reinforcement featuring a crown reinforcement composed of two working layers with angled inextensible elements, a layer of circumferential reinforcement elements distributed with a variable pitch, and a protective layer, which provides varying stiffness and improved rigidity to withstand stresses while reducing wear and enhancing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional crown reinforcement with constant pitch circumferential elements is used, then manufacturing is simple, but the tire shows pronounced wear in the center under high-speed road conditions
Solution Approach 1:
The patent applies local quality by varying the pitch of circumferential reinforcement elements along the axial direction. The pitch is smaller in the central zone (0.8-1.2 times the nominal pitch) and larger in the intermediate zones (1.2-1.5 times the nominal pitch), creating different reinforcement densities in different regions to match the specific stress and wear conditions of each zone.
2Reliability
If the pitch of circumferential reinforcement elements is reduced uniformly across the tire, then wear resistance improves, but material usage and manufacturing costs increase
Solution Approach 1:
The patent reduces material usage by applying smaller pitch only where needed (central zone with higher wear risk) while using larger pitch in intermediate zones where less reinforcement is required, optimizing the balance between wear resistance and material consumption.
Solution Approach 2:
The circumferential reinforcement layer is segmented into different zones (central zone and intermediate zones) with different pitch values, allowing optimized material distribution that reduces overall material usage while maintaining wear resistance where it is most needed.
3Reliability
If circumferential reinforcement elements are concentrated in the central zone, then center wear resistance improves, but rigidity at the ends decreases
Solution Approach 1:
The patent maintains rigidity at axial ends by providing circumferential reinforcement elements throughout the entire axial width, with varying pitch values. The smaller pitch in the central zone enhances wear resistance there, while the presence of elements (with larger pitch) in intermediate zones maintains sufficient rigidity at the ends.
4Reliability
If a variable pitch distribution is implemented, then wear uniformity improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific pitch ranges for different zones (central zone: 0.8-1.2 times nominal pitch; intermediate zones: 1.2-1.5 times nominal pitch) that provide clear manufacturing targets while achieving improved wear uniformity through the variable distribution.
Data Source
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AI summary
The invention relates to a tyre including a crown reinforcement (4) radially covered by a tread, the crown reinforcement including at least one layer of circumferential reinforcing elements (42) axially distributed according to a variable spacing. According to the invention, the layer of circumferential reinforcing elements comprises at least five portions, i.e. a central portion (421), two intermediate portions (422) and two axially outer portions (423), the value of the spacing in the central portion being 1 to 1.5 times the value of the spacing in the axially outer portions, and the value of the spacing in an intermediate portion being 1.6 to 2 times the value of the spacing in the axially outer portions.