Thin Tread Rubber Composition for High-Speed Chipping Resistance
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Solution Overview
Problem
The chipping resistance performance of tires on rough road surfaces at high speeds is insufficient despite previous improvements in rubber composition and tread surface design.
Innovation Solution
A tire with a tread portion thickness of 15 mm or less, featuring a cap rubber layer composed of 40-80 parts by mass styrene-butadiene rubber (SBR) with 25% or less styrene content, combined with silica and carbon black, and a loss tangent of 0.18 or more at 30°C, ensuring enhanced energy absorption and deformation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the tread portion thickness is increased to improve chipping resistance, then the strength and durability improve, but the rolling resistance increases and fuel efficiency deteriorates
Solution Approach 1:
The patent optimizes the tread thickness parameter to 15 mm or less to reduce rolling resistance while compensating for reduced chipping resistance through chemical composition changes in the rubber compound. This parameter change allows maintaining adequate protection against chipping while minimizing energy loss during rolling.
Solution Approach 2:
The patent uses a composite rubber compound containing specific ratios of SBR (40-80 parts), silica (20-60 parts), and carbon black (15-40 parts) to create a multi-functional material that provides both chipping resistance and low rolling resistance properties in a thin tread structure.
2Strength
If conventional rubber compositions are used to maintain flexibility, then the tire remains comfortable, but chipping resistance on rough roads at high speed is insufficient
Solution Approach 1:
The patent adjusts the loss tangent parameter (tan δ at 30°C) to be 0.18 or more, which optimizes the balance between flexibility for comfort and strength for chipping resistance. This specific parameter range ensures the rubber remains supple during normal operation while providing enhanced resistance to chipping under high-stress conditions.
Solution Approach 2:
The patent applies different material properties to different functional requirements: the rubber compound is designed with high elasticity and low stiffness for comfort during normal driving, while simultaneously incorporating reinforcing fillers and specific molecular structures that provide localized strength and resistance to chipping when subjected to high-speed rough road conditions.
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 performance on rough road surfaces at high speeds due to the specific rubber composition and tread thickness, which reduces deformation and heat accumulation, maintaining high strength during rolling.
Implementation Method 1
having loss tangent 30° C. tan δ of more than 0.18 measured under the conditions of temperature of 30° C., frequency of 10 Hz, initial strain of 5%, dynamic strain rate of 1%, and deformation mode: tensile
Data Source
AI summary
Provided is a tire having a tread portion with a thickness of 15 mm or less, wherein the cap rubber layer forming the tread portion is formed from a rubber composition containing 40 parts by mass or more and 80 parts by mass or less of styrene-butadiene rubber (SBR) with a styrene content of 25% by mass or less, in 100 parts by mass of the rubber component, and in addition to the rubber component, containing silica and carbon black; and having loss tangent 30° C. tan δ of more than 0.18 measured under the conditions of temperature of 30° C., frequency of 10 Hz, initial strain of 5%, dynamic strain rate of 1%, and deformation mode: tensile; wherein the carbon black content is 15 parts by mass or more with respect to 100 parts by mass of the rubber component, and the ratio of the silica content to the carbon black content is 1 or more; and an object of the present invention is to improve chipping resistance performance when running on a rough road surface at high speed.