Tire Tread Rubber Composition for Lower Start-Up Rolling Resistance
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Solution Overview
Problem
Conventional tires exhibit insufficient rolling resistance, particularly at the time of starting, despite advancements in reducing rolling resistance during running.
Innovation Solution
A tire design featuring a cap rubber layer composed of a rubber composition containing 60 to 80 parts by mass of styrene-butadiene rubber with a styrene content of 20% or less and up to 100 parts by mass of silica, with a loss tangent of 0.25 or less, and a tread thickness between 6 to 12 mm, optimized for improved force transmission and reduced energy absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the cap rubber layer uses high silica content to reduce rolling resistance, then energy loss during running decreases, but force transmission at start-up becomes insufficient
Solution Approach 1:
The patent optimizes the silica content parameter to 100 parts by mass or less per 100 parts rubber component, which balances the competing requirements: sufficient silica to reduce rolling resistance through low loss tangent, but not so much that it compromises force transmission capability at start-up
2Force
If the tread portion thickness is increased to improve force transmission, then rolling resistance at start-up improves, but heat generation increases
Solution Approach 1:
The patent sets the tread portion thickness within the specific range of 6-12 mm, which optimizes the balance between force transmission capability and heat generation. This parameter range provides sufficient material depth for effective force transmission while limiting the thickness to prevent excessive heat buildup during operation
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
Enhances rolling resistance at the time of starting by facilitating efficient force transmission to the road surface, reducing heat generation, and improving responsiveness.
Implementation Method 1
whose loss tangent (30°C tan δ) measured in deformation mode: tensile under the conditions of temperature of 30°C, frequency of 10 Hz, initial strain of 5%, and dynamic strain rate of 1% is 0.25 or less
Data Source
AI summary
It is provided a tire having a tread portion, wherein the cap rubber layer forming the tread portion is formed from a rubber composition containing 60 parts by mass or more and 80 parts by mass or less of styrene-butadiene rubber having a styrene content of 25% by mass or less in 100 parts by mass of the rubber component, and containing 100 parts by mass or less of silica with respect to 100 parts by mass of the rubber component, whose loss tangent (30°C tan δ) is 0.25 or less; and the thickness of the tread portion is 6 mm or more and 12 mm or less; and an object of the present invention is to improve rolling resistance at the time of starting.