Pneumatic Tire Tread Composition for Low Rolling Resistance and Wet Grip
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Solution Overview
Problem
Current pneumatic tires face a challenge in achieving both low rolling resistance and improved wet grip performance, as compositions that reduce rolling resistance tend to compromise wet grip, and vice versa, limiting the ability to meet both social demands for fuel efficiency and safety.
Innovation Solution
A pneumatic tire design incorporating a rubber composition for the tread part with a specific range of tan δ values, featuring a high percentage of natural rubber, modified styrene-butadiene copolymer rubber, and thermoplastic resin, along with a reinforcing filler like silica, and a carbon black with a nitrogen adsorption specific surface area of 25 to 43 m²/g for the tread and chafer parts, optimizing both rolling resistance and wet grip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rubber composition with high tan δ at 0°C is used to improve wet grip performance, then wet grip properties are improved, but tan δ at 60°C increases, leading to increased rolling resistance
Solution Approach 1:
The patent applies parameter changes by precisely controlling the tan δ values at different temperatures through specific rubber composition formulation. The tread rubber composition is designed to achieve tan δ at 0°C of 0.65 to 1.05 and tan δ at 60°C of 0.15 to 0.35, creating an optimized parameter range that simultaneously improves wet grip while limiting rolling resistance increase. This quantitative parameter control resolves the contradiction by finding the optimal balance point between the two opposing requirements.
Solution Approach 2:
The patent uses composite materials by combining multiple rubber components (natural rubber, styrene-butadiene copolymer, thermoplastic resin) with specific fillers (silica, carbon black) and additives in precise proportions. This composite formulation creates a multi-phase rubber composition where each component contributes different properties: natural rubber provides wet grip, while the combination with thermoplastic resin and controlled filler content manages the tan δ at 60°C to limit rolling resistance. The composite structure allows simultaneous optimization of both contradictory properties.
2Loss of energy
If a rubber composition with low tan δ at 60°C is used to reduce rolling resistance, then rolling resistance is reduced, but tan δ at 0°C decreases, leading to reduced wet grip properties
Solution Approach 1:
The patent applies parameter changes by establishing specific target ranges for tan δ at both temperatures. By setting tan δ at 0°C between 0.65-1.05 and tan δ at 60°C between 0.15-0.35, the invention creates an optimized parameter window that prevents the trade-off from occurring. The composition formulation and curing system are specifically designed to achieve these parameter targets, ensuring both low rolling resistance and adequate wet grip are obtained simultaneously.
Solution Approach 2:
The patent uses composite materials with a specific formulation: natural rubber (50-95 parts), styrene-butadiene copolymer (5-50 parts), thermoplastic resin (10-50 parts), silica (20-120 parts), and carbon black (20-80 parts). This composite composition allows the tread to achieve low tan δ at 60°C for reduced rolling resistance while maintaining sufficient tan δ at 0°C for wet grip through the synergistic effects of the multiple components and their interactions.
3Use of energy by moving object
If rolling resistance is reduced to improve fuel efficiency, then fuel efficiency is improved, but heat generation reduction causes tire temperature to decrease, reducing deformation and followability on low temperature road surfaces
Solution Approach 1:
The patent applies parameter changes by controlling the tan δ temperature dependence through specific composition formulation. The tread rubber is designed to maintain appropriate tan δ values across a wide temperature range, ensuring that even when overall heat generation is reduced, the tire maintains sufficient deformation capability and road surface followability at low temperatures. The specific tan δ ranges at different temperatures are optimized to balance fuel efficiency and followability.
Solution Approach 2:
The patent applies local quality by creating different rubber compositions for different tire parts. The tread rubber composition is specifically formulated with thermoplastic resin and controlled filler content to achieve low tan δ at 60°C for fuel efficiency while maintaining adequate properties at lower temperatures for followability. This localized optimization of the tread composition allows the tire to achieve both improved fuel efficiency and maintained road surface followability in the critical contact region.
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 low rolling resistance and improved wet grip performance across a wide temperature range, enhancing fuel efficiency and safety by maintaining flexibility and road surface followability while reducing heat build-up and braking distance.
Implementation Method 1
a rubber composition having a tan δ in a specific range
Implementation Method 2
a carbon black having a nitrogen adsorption specific surface area: N 2 SA
Data Source
Figure 1
AI summary
Provided is a pneumatic tire having both low rolling resistance and a wet property during ground contact with a low temperature road surface; the pneumatic tire including: a tread part formed by using a rubber composition containing specific amounts of natural rubber, a modified styrene-butadiene copolymer rubber, a reinforcing filler, and a thermoplastic resin; and a rubber chafer part formed by using a rubber composition containing a large particle size carbon black identified with a particular physical property.