Pneumatic Tire Two-Layer Tread with Foamed Cap
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Solution Overview
Problem
Conventional cold weather tires face challenges in achieving balanced performance across handling stability, grip, fuel economy, and road noise on snow- and ice-free cold roads, while maintaining conductivity and performance on ice and snow, due to significant differences in rubber properties between cap and base treads.
Innovation Solution
A pneumatic tire design featuring a two-layer tread with a base tread composed of natural rubber, polyisoprene rubber, silica, and carbon black, and a cap tread with high silica content and cells or voids, optimizing the rubber composition to improve handling stability, grip, and fuel economy, while ensuring conductivity and performance on ice and snow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the cap tread contains a large amount of silica to improve fuel economy and wet grip performance, then fuel economy and wet grip are improved, but the difference in rubber physical properties between the cap tread and base tread increases, causing poor handling stability and road noise generation
Solution Approach 1:
The patent applies local quality by creating distinct rubber compositions for different tread zones: the cap tread uses high silica content (50-90 parts per 100 parts rubber) for fuel economy and wet grip, while the base tread uses carbon black (30-60 parts per 100 parts rubber) for durability and rigidity. This localized differentiation allows each zone to optimize its properties without compromising overall tire performance.
Solution Approach 2:
The patent employs composite materials by combining silica and carbon black fillers in specific ratios and distributions across the two-layer tread structure. The cap tread comprises silica-rubber composite for low rolling resistance, while the base tread uses carbon black-rubber composite for structural integrity, creating a synergistic multi-material system that resolves the contradiction between fuel economy and handling stability.
2Use of energy by moving object
If the cap tread contains a large amount of silica to improve fuel economy, then fuel economy is improved, but tire conductivity deteriorates
Solution Approach 1:
The patent segments the filler distribution by confining high silica content to the cap tread layer while maintaining high carbon black content in the base tread layer. This spatial segmentation allows the silica-rich cap tread to deliver fuel economy benefits while the carbon black-rich base tread ensures adequate electrical conductivity for the entire tire structure.
3Duration of action of stationary object
If the base tread has high rigidity and high rubber density to ensure durability, then durability is improved, but the difference in physical properties from foamed cap tread increases, causing poor high speed performance
Solution Approach 1:
The patent applies parameter changes by controlling the foam expansion ratio of the cap tread within 30-150% and adjusting the cell structure parameters (cell size, cell wall thickness) to optimize the balance between lightness and structural integrity. This allows the foamed cap tread to reduce weight for high-speed performance while the dense base tread maintains durability through controlled rigidity parameters.
Data Source
AI summary
The present invention provides a cold weather tire achieving a balanced improvement in conductivity, fuel economy, performance on ice and snow, high speed performance (handling stability, grip performance) on snow- and ice-free cold roads, and road noise performance. Provided is a pneumatic tire including: a two-layer tread including a base tread and a cap tread, the base tread being formed of a rubber composition for base treads containing: predetermined amounts of a rubber component including natural rubber and/or polyisoprene rubber, and a filler including silica and carbon black, the cap tread being formed of a rubber composition for cap treads containing a predetermined amount of silica, the cap tread having cells and/or voids.