Passenger Car Radial Tire Tread for Low-Temp Comfort and High-Speed Stability
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Solution Overview
Problem
Conventional radial tires for passenger cars fail to simultaneously achieve riding comfort at low temperatures and steering stability at high speeds, despite advancements in rubber composition and tread patterns.
Innovation Solution
A pneumatic radial tire design with specific tread shape and rubber composition characteristics, including a cross-sectional width and outer diameter ratio, land/sea ratio, loss tangent values, and a two-layer rubber structure, to optimize contact area and maintain stability at varying temperatures and speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the tread rubber composition is optimized for low temperature flexibility, then riding comfort at low temperature is improved, but steering stability at high speed deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the loss tangent values at different temperatures. Specifically, it sets |20°C tan δ-50°C tan δ| to 0.01 or more and less than 0.15, and |5°C tan δ-20°C tan δ| to more than 0.15 and less than 0.70. This dual-parameter control allows the rubber to exhibit appropriate flexibility at low temperatures for comfort while maintaining sufficient stiffness at high temperatures for steering stability.
Solution Approach 2:
The patent uses composite materials by combining specific rubber components (diene-based rubber 35-70 parts, styrene-butadiene copolymer rubber 10-40 parts, halogenated butyl rubber 5-20 parts) with controlled silica content (20-40 parts) and sulfur content (0.5-2.0 parts). This composite formulation creates a tread material that achieves both low-temperature flexibility and high-temperature stability simultaneously.
2Ease of operation
If the contact area is increased to improve riding comfort, then low temperature comfort is improved, but steering response and stability at high speed may deteriorate
Solution Approach 1:
The patent applies local quality by creating a two-layer tread structure with different rubber compositions. The lower layer (base rubber layer) has higher silica content (30-50 parts) for flexibility and comfort, while the upper layer (cap rubber layer) has lower silica content (10-30 parts) for stability and steering response. This layered approach allows different regions of the tread to optimize for different functions.
Solution Approach 2:
The patent applies dynamics by designing the tread to dynamically adjust its effective stiffness based on operating conditions. The specific loss tangent characteristics enable the tread to be more compliant at low temperatures for comfort while automatically becoming stiffer at high temperatures for steering stability, without requiring active control mechanisms.
3Ease of operation
If the tread rubber is made softer to improve comfort, then riding comfort is improved, but high-speed steering stability deteriorates
Solution Approach 1:
The patent uses parameter changes by controlling the loss tangent temperature dependence rather than simply adjusting overall hardness. By setting specific ranges for |20°C tan δ-50°C tan δ| and |5°C tan δ-20°C tan δ|, the tread achieves apparent softness for comfort while maintaining the necessary stiffness at operating temperatures for steering stability.
Solution Approach 2:
The patent employs composite materials with a specific multi-component rubber system where halogenated butyl rubber (5-20 parts) and styrene-butadiene copolymer rubber (10-40 parts) are combined with diene-based rubber (35-70 parts). This composite formulation creates a tread that feels soft for comfort but maintains structural integrity and stability at high speeds through the synergistic effects of the rubber 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 provides enhanced riding comfort at low temperatures and improved steering stability at high speeds by securing a sufficient contact area and maintaining optimized tread ground contact shape through synergistic effects of tread shape and rubber properties.
Implementation Method 1
regarding loss tangent (tan δ) of the rubber composition forming the tread measured under the conditions of a frequency of 10 Hz, an initial strain of 2%, and a dynamic strain rate of 1%
Data Source
AI summary
Provided is a pneumatic radial tire for a passenger car that exhibits both riding comfort at low temperatures and stealing stability at high-speed running. The present invention is a pneumatic radial tire for a passenger car, in which: a carcass and a tread are provided; the tread is integrated into a standardized rim; when internal pressure is at a standardized internal pressure, the tire has a cross-sectional width Wt (mm) and an outer diameter Dt (mm) satisfying 1963.4≤(Dt2π/4)/Wt≤2827.4; the tread comprises at least one main groove in a running surface of the tread, extending in the circumferential direction of the tread; the land/sea ratio at the tread running surface is greater than 55% and less than 85%; and a rubber composition that forms the tread has a loss tangent (tan δ) which, when measured at a frequency of 10 Hz, an initial strain of 2%, and a dynamic strain rate of 1%, is such that |20° C. tan δ-50° C. tan δ| is at least 0.01 and less than 0.15, and |5° C. tan δ-20° C. tan δ| is greater than 0.15 and less than 0.70.