Pneumatic Tire Tread Design for Steering Stability and Rolling Resistance
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Solution Overview
Problem
There is a trade-off between steering stability and rolling resistance in tires, where improving steering stability on dry and wet road surfaces worsens rolling resistance, and existing rubber compositions fail to significantly enhance steering stability without worsening rolling resistance.
Innovation Solution
A pneumatic tire design featuring lug grooves and widthwise sipes with a specific rubber composition that includes 50% or more isoprene-based rubber, thermoplastic resin, and 70% silica filler, along with a tread edge component ratio of 6.0 to 8.0, which improves steering stability without increasing rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rubber composition is optimized for steering stability on dry and wet road surfaces, then steering stability is improved, but rolling resistance worsens
Solution Approach 1:
The patent applies parameter changes by precisely controlling the loss tangent (tanδ) at different temperatures. Specifically, tanδ at 0°C is set to 0.95 or higher, tanδ at 60°C is set to 0.50 or lower, and the difference between tanδ at 30°C and tanδ at 60°C is set to 0.080 or lower. These parameter adjustments optimize the rubber composition to achieve both improved steering stability and reduced rolling resistance by tuning the viscoelastic properties across different temperature ranges.
Solution Approach 2:
The patent employs composite materials by combining specific rubber components (natural rubber and/or synthetic isoprene rubber) with resin compositions (novolac-type resorcinol resin and resol-type phenolic resin) and thermoplastic resins that are immiscible with the rubber component. This composite structure allows the tire to achieve both high steering stability and low rolling resistance by leveraging the complementary properties of different material components.
2Reliability
If rubber composition is optimized for steering stability on dry and wet road surfaces, then steering stability is improved, but fuel efficiency worsens
Solution Approach 1:
The patent applies parameter changes by precisely controlling the loss tangent (tanδ) at different temperatures. Specifically, tanδ at 0°C is set to 0.95 or higher, tanδ at 60°C is set to 0.50 or lower, and the difference between tanδ at 30°C and tanδ at 60°C is set to 0.080 or lower. These parameter adjustments optimize the rubber composition to achieve both improved steering stability and reduced rolling resistance by tuning the viscoelastic properties across different temperature ranges.
Solution Approach 2:
The patent employs composite materials by combining specific rubber components (natural rubber and/or synthetic isoprene rubber) with resin compositions (novolac-type resorcinol resin and resol-type phenolic resin) and thermoplastic resins that are immiscible with the rubber component. This composite structure allows the tire to achieve both high steering stability and low rolling resistance by leveraging the complementary properties of different material components.
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 achieves enhanced steering stability on dry and wet surfaces while maintaining low rolling resistance, with reduced temperature dependence and improved tread rigidity and deformation.
Implementation Method 1
in the rubber composition, tanδ at 0°C is 0.5 or less, the difference between tanδ at 30°C and tanδ at 60°C is 0.070 or less
Data Source
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AI summary
Provided is a pneumatic tire that can greatly improve the steering stability on dry and wet road surfaces without worsening of the rolling resistance. A rubber composition used in a tread (10) of the pneumatic tire includes a rubber component (A) including 50 mass% or more of isoprene-based rubber, a specific amount of a thermoplastic resin (B), and a filler (C) including 70 mass% or more of silica. In the rubber composition, tanδ at 0°C is 0.5 or less, the difference between tanδ at 30°C and tanδ at 60°C is 0.070 or less, and the storage modulus at a dynamic strain of 1% and 0°C is 20 MPa or less. In the pneumatic tire, a tread edge component ratio defined as (sum of tire widthwise extending length of lug grooves and tire widthwise extending length of widthwise sipes on the tread surface)/(tire circumferential length) is 6.0 to 8.0.