Studless Tire Cap Tread Viscoelasticity Ice Handling
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Solution Overview
Problem
Studless winter tires lack the handling stability on ice and snow, and existing solutions fail to provide effective indicators for improving this stability.
Innovation Solution
A tire design with a cap tread and base tread that satisfies specific relationships between the average thickness of the cap tread and base tread, and specific viscoelastic properties, using a rubber composition that includes isoprene-based rubber and terpenic resin, to enhance handling stability on ice and snow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If studless winter tires are designed without physical projections, then environmental damage is reduced, but handling stability on ice and snow deteriorates
Solution Approach 1:
The invention changes the physical parameters of the tread rubber by controlling the ratio of loss tangent at -30°C to complex modulus at 0°C to be 0.16 or more, and setting specific thickness ratios between cap and base treads. This parameter optimization enables studless tires to achieve handling stability comparable to studded tires while avoiding road surface damage
Solution Approach 2:
The invention uses composite rubber compositions in the cap and base treads with specific viscoelastic properties. The cap tread rubber composition is designed to have specific tan δ and E* values, creating a multi-layer composite structure that provides both environmental friendliness and handling stability on ice and snow
2Reliability
If rubber compound properties are improved to enhance handling stability on ice, then performance on ice improves, but manufacturing complexity increases
Solution Approach 1:
Instead of complex multi-component rubber formulations, the invention simplifies the approach by focusing on controlling two key viscoelastic parameters (tan δ at -30°C and E* at 0°C) and their ratio. This parameter-based approach achieves handling stability without requiring complicated compound formulations
Solution Approach 2:
The invention applies different rubber compositions with specific viscoelastic properties to different regions (cap tread and base tread), where the cap tread rubber is specifically designed to have tan δ/E* ≥ 0.16. This localized quality approach optimizes ice handling without complicating the entire tire structure
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 design provides excellent handling stability on ice and snow, while also improving dry handling stability and abrasion resistance, and reducing production costs.
Implementation Method 1
tan δc represents a -30°C tan δ (a loss tangent measured at a temperature of -30°C, an initial strain of 10%, a dynamic strain of 2.5%, and a frequency of 10 Hz) of the cap tread, and E*c represents a 0°C E* (a complex modulus measured at a temperature of 0°C, an initial strain of 10%, a dynamic strain of 2.5%, and a frequency of 10 Hz) of the cap tread
Data Source
Figure 1
AI summary
Provided are tires with excellent handling stability on ice and snow. Included is a tire which includes a cap tread and a base tread, and satisfies the following relationships (1) and (2): 0.4≦TcTb≦1.5 wherein Tc represents the average thickness of the cap tread, and Tb represents the average thickness of the base tread, and tanδcE∗c≧0.16 wherein tan δc represents the -30°C tan δ (the loss tangent measured at a temperature of -30°C, an initial strain of 10%, a dynamic strain of 2.5%, and a frequency of 10 Hz) of the cap tread, and E*c represents the 0°C E* (the complex modulus measured at a temperature of 0°C, an initial strain of 10%, a dynamic strain of 2.5%, and a frequency of 10 Hz) of the cap tread.