Tyre Tread Cutouts and Calendering Layers for Wear
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Solution Overview
Problem
Current heavy-duty tires face issues with wear regularity and rolling resistance, particularly when featuring alternating hidden hollows in the tread, which can lead to irregular wear patterns and increased fuel consumption.
Innovation Solution
A tire design with a radial carcass reinforcement including a crown reinforcement of two working layers with calendered rubber mixtures, a layer of circumferential reinforcing elements, and specific tread cutouts with hidden hollows, where the calendering layers have a modulus of elasticity greater than 9 MPa and a loss factor tan(δ) max less than 0.100, enhancing the tire's endurance and rolling resistance properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If alternating hidden hollows are introduced in the tread to improve rolling resistance, then rolling resistance is reduced, but wear regularity deteriorates
Solution Approach 1:
The patent applies local quality by differentiating the geometry of cutouts in different regions of the tread. Central cutouts have a first geometry optimized for rolling resistance, while lateral cutouts have a second geometry that prevents water accumulation. This local differentiation allows the tread to simultaneously achieve low rolling resistance through central hollows while maintaining wear regularity by preventing water pooling at the edges that would cause irregular wear patterns.
Solution Approach 2:
The tread is segmented into different zones with distinct cutout patterns. The central region contains alternating hidden hollows for reducing rolling resistance, while the lateral regions have different cutout geometries for water management. This segmentation allows each zone to perform its specific function independently, resolving the contradiction between rolling resistance improvement and wear regularity maintenance.
2Loss of energy
If calendering layers with high modulus of elasticity (>9 MPa) and low loss factor (tanδ max <0.100) are used, then rolling resistance is improved, but wear regularity may deteriorate
Solution Approach 1:
The patent specifies precise parameter ranges for the calendering rubber mixtures: modulus of elasticity greater than 9 MPa and maximum loss factor tanδ less than 0.100. By carefully controlling these material parameters, the invention achieves low rolling resistance through reduced hysteresis losses while maintaining sufficient cohesion and adhesion properties to ensure regular wear. The parameter optimization balances energy efficiency with wear performance.
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 tire design maintains satisfactory wear regularity and endurance while improving rolling resistance, contributing to reduced fuel consumption and prolonged tire life by controlling deformations and cohesion of the rubber mixtures.
Implementation Method 1
the modulus of elasticity under tension at 10% elongation of the calendering layers of the working crown layers being greater than 9 MPa and the maximum value of tan(δ), denoted tan(δ)max, of the calendering layers of the working crown layers being less than 0.100
Implementation Method 2
the modulus of elasticity under tension at 10% elongation of the calendering layers of the working crown layers being greater than 9 MPa and the maximum value of tan(δ), denoted tan(δ)max, of the calendering layers of the working crown layers being less than 0.100
Data Source
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AI summary
The invention relates to a tyre including a crown reinforcement formed of at least two working crown plies (41, 43) of reinforcement elements and at least one ply (42) of circumferential reinforcement elements. According to the invention, the tread has at least one cut-out made up of at least two portions (8, 9), the ratio of the width of the first portion (9), measured at the bottom, to the width of said at least one first portion, measured at the surface of the tread on a new tyre, being strictly greater than 2, the ratio of the width of the second portion (8), measured at the surface of the tread on a new tyre, to the width of said at least one second portion, measured at the bottom, being no lower than 1, the modulus of elasticity under tension at 10% elongation of at least one liner layer of at least one working crown ply being greater than 9 MPa, and the maximum value of tan(8), noted as tan(8)max, of said at least one liner layer of at least one working crown ply being lower than 0.100.