Multilayer Heavy-Duty Tire Tread for High-Speed Chipping Control
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Solution Overview
Problem
Heavy duty tires face challenges in maintaining chipping resistance during high-speed running, as existing solutions do not adequately address the issue of heat build-up and stress concentration in the tread portion, leading to potential chipping.
Innovation Solution
A heavy duty tire design featuring a tread portion with a multilayer structure comprising a cap rubber layer and a base rubber layer, where the cap rubber layer contains polybutadiene rubber and carbon black, with specific thickness and complex modulus ratios that ensure effective deformation and stress distribution, enhancing chipping resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-layer tread rubber structure is used, then the manufacturing process is simple, but the chipping resistance during high-speed running is insufficient due to heat build-up and stress concentration
Solution Approach 1:
The tread rubber is divided into multiple layers with different compositions and properties. The cap rubber layer (outer layer) and base rubber layer (inner layer) are segmented to perform different functions: the cap layer provides flexibility and chipping resistance, while the base layer provides structural support and heat dissipation, resolving the contradiction between reliability and complexity.
Solution Approach 2:
The patent uses composite rubber materials with specific formulations in each layer. The cap rubber layer contains polybutadiene rubber and carbon black in specific proportions to optimize elasticity and heat resistance, while the base layer uses different composition ratios, creating a composite structure that simultaneously improves chipping resistance and manages thermal stress.
2Reliability
If the cap rubber layer is made thicker to improve chipping resistance, then the chipping resistance increases, but the overall tire structure becomes less balanced in terms of stress distribution
Solution Approach 1:
The patent applies local quality by making the cap rubber layer thicker specifically in the shoulder region where chipping is most likely to occur, while maintaining a thinner base layer in this region. This localized adjustment optimizes chipping resistance at the critical area without compromising overall structural balance and stress distribution.
Solution Approach 2:
The patent optimizes the thickness ratio parameters between cap and base rubber layers, specifically setting the cap layer thickness to 0.5-2.0 times the base layer thickness in the shoulder region. This parameter optimization ensures adequate chipping resistance while maintaining proper stress distribution and structural integrity.
3Reliability
If rubber layers with different compositions are used to optimize performance, then chipping resistance improves, but the manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific parameter ranges for layer thickness ratios (0.5-2.0 times) and rubber composition proportions rather than requiring exact values. This approach maintains manufacturing flexibility while ensuring adequate performance, reducing the stringency of precision requirements compared to fixed-specification designs.
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 exhibits improved chipping resistance during high-speed running by reducing heat build-up and stress concentration, thereby extending its durability and performance.
Implementation Method 1
the cap rubber layer can deform so that the input from the road surface can be easily released
Implementation Method 2
the tread portion exhibits reduced heat build-up
Data Source
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Figure 2
AI summary
Provided is a heavy duty tire having excellent chipping resistance during high-speed running. Included is a heavy duty tire including a tread portion, the tread portion including a shoulder region located axially outward from an axially outermost main longitudinal groove extending in a circumferential direction, the tread portion being provided with a tread rubber consisting of a multilayer structure including a cap rubber layer forming a tread outer surface and a radially innermost base rubber layer, the cap rubber layer in the shoulder region containing at least one rubber component including a polybutadiene rubber and a carbon black, the heavy duty tire satisfying the following relationships (1) to (3): (1) Tb/Tc ≤ 0.50; (2) Eb'/Ec' ≤ 0.60; and (3) Bca/(Tb/Tc) ≥ 40 wherein Tc, Ec', Tb, Eb' and Bca are defined herein.