Low-Aspect Heavy-Duty Tire Band Structure for Sidewall Strain
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Solution Overview
Problem
Heavy duty tires with low nominal aspect ratios face challenges in durability and uneven wear resistance due to strain in the side portions, particularly when using bands to prevent radial growth, which can lead to damage and reduced durability.
Innovation Solution
A heavy duty tire design featuring a tread with circumferential grooves, a spirally wound band with edge bands, and a fitting recess on the chafer to reduce strain and improve wear resistance, including specific ratios and dimensions for the band and tread widths, and the location of the band ends relative to the grooves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a band is used to suppress radial growth of the tire, then uneven wear resistance is improved, but strain occurs in the side portion leading to reduced durability
Solution Approach 1:
The band structure is differentiated into a full band extending across the tire width and edge bands positioned at the shoulder portions. This local differentiation allows the full band to suppress radial growth for uneven wear prevention, while the edge bands specifically address strain concentration at the side portions, resolving the contradiction between wear resistance and durability.
Solution Approach 2:
The band is segmented into multiple functional zones: the full band for overall radial growth suppression and edge bands for localized strain management at the shoulders. This segmentation allows each zone to perform its specific function, preventing strain-induced damage while maintaining uneven wear resistance.
2Shape
If the aspect ratio is reduced to 65% or less, then the tire profile is improved, but strain in the side portion increases due to shorter side wall length
Solution Approach 1:
The edge bands are specifically positioned at the shoulder portions where strain concentrates in low aspect ratio tires. This local reinforcement compensates for the shorter side wall length, maintaining durability while preserving the improved tire profile of 65% aspect ratio or less.
3Stability of the object's composition
If the band suppresses stretch of side portion, then radial growth is controlled, but specific strain occurs in the side portion
Solution Approach 1:
The band is divided into the full band for radial growth control and edge bands for strain distribution at the shoulders. This segmentation allows radial growth suppression while preventing strain concentration, as the edge bands provide additional support where strain would otherwise accumulate.
Solution Approach 2:
The edge bands act as intermediary elements between the full band and the side portions. They mediate the stress distribution, transferring and distributing the suppressive force more evenly, thereby preventing specific strain points while maintaining overall radial growth control.
Data Source
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AI summary
A tire 2 has a nominal aspect ratio of 65% or less. The tire 2 includes a tread 4, a pair of sidewalls 6, a pair of chafers 8, a pair of beads 10, and a band 40. The band 40 includes a full band 44 having ends 44e opposed to each other across an equator plane, and a pair of edge bands 46 located outward of the ends 44e of the full band 44 in a radial direction. An outer surface of each chafer 8 has a fitting recess 62 into which a flange F of a rim R fits.