Tire Tread Rubber Composition for Braking and Steering Stability
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Solution Overview
Problem
Tires with existing tread rubber compositions face challenges in achieving improved braking performance on dry and wet road surfaces while maintaining steering stability, particularly on slippery surfaces like manholes, and there is a trade-off between braking performance and steering stability due to variations in tread rigidity.
Innovation Solution
A tire with a tread formed by a rubber composition having specific physical properties, including a tan δ at 0°C of 0.25 to 0.55, a difference in tan δ between 30°C and 60°C of -0.02 to 0.07, and a dynamic storage modulus of 4 MPa to 20 MPa, featuring a circumferential groove and other grooves within specific negative ratio ranges, along with a central land portion and side regions, and the use of specific additives like thermoplastic resins and carbon black to enhance land portion rigidity and braking performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rubber composition formulation is optimized to improve braking performance on dry and wet road surfaces, then braking performance is improved, but tread rigidity deteriorates and steering stability worsens
Solution Approach 1:
The patent applies parameter changes by precisely controlling the tan δ at 0°C within 0.25 to 0.55 and the difference between tan δ at 30°C and 60°C within -0.02 to 0.07. These parameter specifications optimize the rubber composition to achieve both improved braking performance on dry and wet surfaces while maintaining adequate tread rigidity for steering stability.
Solution Approach 2:
The patent uses composite materials by combining rubber composition with specific physical properties (controlled tan δ and dynamic storage modulus) and integrating it with a tread pattern featuring circumferential grooves and land portions with specific negative ratios. This composite approach allows simultaneous optimization of braking performance and steering stability.
2Reliability
If the tan δ at 0°C is increased to improve wet road surface gripping performance, then wet braking performance is improved, but fuel efficiency in low temperature environment deteriorates
Solution Approach 1:
The patent applies parameter changes by specifying the tan δ at 0°C within 0.25 to 0.55, which balances wet road surface gripping performance with fuel efficiency in low temperature environments. Additionally, the difference between tan δ at 30°C and 60°C is controlled within -0.02 to 0.07 to further optimize the energy loss characteristics across different temperatures.
Solution Approach 2:
The patent applies local quality by differentiating the performance requirements at different temperatures. The rubber composition is designed to have specific loss properties at low temperature (tan δ at 0°C) for wet braking performance while controlling the temperature dependence (difference between tan δ at 30°C and 60°C) to minimize fuel efficiency deterioration.
3Reliability
If the tread rigidity is reduced to improve braking performance on slippery surfaces, then braking performance is improved, but steering stability deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the dynamic storage modulus at a dynamic strain of 1% and 0°C within 4 MPa to 20 MPa. This parameter specification allows the tread to have sufficient flexibility for braking performance on slippery surfaces while maintaining adequate rigidity for steering stability.
Solution Approach 2:
The patent applies dynamics by making the tread rigidity temperature-dependent through the controlled tan δ characteristics. The tread becomes more flexible at low temperatures for improved braking on slippery surfaces while maintaining appropriate rigidity at operating temperatures for steering stability.
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 excellent braking performance on both dry and wet surfaces and maintains excellent steering stability by optimizing tread rigidity and drainage performance through the specified rubber composition and groove configurations.
Implementation Method 1
improve the braking performance on dry road surface and on wet road surface
Implementation Method 2
improve the gripping performance on wet road surface
Implementation Method 3
the tread has a circumferential groove extending continuously in a tire circumferential direction... better wet braking performance is requested on a road surface which is more slippery as compared to asphalt
Data Source
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AI summary
This disclosure aims to provide a tire having excellent braking performance on dry road surface and on wet road surface, and having excellent steering stability. This disclosure is a tire comprising a tread 10 formed by using a rubber composition of which a tan δ at 0°C is 0.25 to 0.55, a difference between a tan δ at 30°C and a tan δ at 60°C is -0.02 to 0.07, and a dynamic storage modulus at a dynamic strain of 1% and 0°C is 4 MPa to 20 MPa, wherein: the tread 10 has circumferential grooves 20 extending in a tire circumferential direction C; a negative ratio in a footprint is 15% to 25%; a negative ratio derived from the circumferential grooves 20 is 8% to 14%; and a negative ratio derived from grooves other than the circumferential grooves 20 is 7% to 11%.