Tread Groove and Rubber Hardness Design for Worn Wet-Ice Handling
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Solution Overview
Problem
Conventional tires exhibit inadequate handling stability on wet and icy roads when worn, necessitating improvements in overall performance.
Innovation Solution
A tire design with a tread portion featuring a main groove extending in the tire circumferential direction, utilizing rubber with specific hardness properties and a S50/S0 ratio greater than 1, ensuring increased grooves as the tire wears, and incorporating a temperature-responsive polymer composite to adjust hardness based on temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional tire rubber is used, then the tire provides adequate initial handling stability, but handling stability deteriorates when the tire is worn
Solution Approach 1:
The patent applies parameter changes by carefully controlling the rubber hardness parameters (JIS-A hardness at 60°C of 58 or higher, and JIS-A hardness at 0°C of not more than 115% of the hardness at 60°C) to achieve optimal performance. This parameter optimization ensures the rubber maintains appropriate softness for road conformity while providing sufficient strength, resolving the contradiction between initial handling stability and worn-state performance.
Solution Approach 2:
The patent uses composite materials by incorporating a temperature-responsive polymer into the rubber composition. This polymer composite changes its properties in response to temperature variations, allowing the tire to adapt to different operating conditions (wet vs. icy roads) and maintain handling stability throughout the tire's service life, thereby extending effective performance duration.
2Reliability
If the tread rubber is made softer to improve road conformity on icy roads, then handling stability on icy roads improves, but water drainage capability deteriorates
Solution Approach 1:
The patent resolves this contradiction through parameter changes by controlling the rubber hardness to be relatively soft (JIS-A hardness at 60°C of 58 or higher, which is not excessively hard) to maintain road conformity on icy surfaces. Simultaneously, the temperature-responsive polymer adjusts the rubber's physical state based on temperature, ensuring adequate water drainage capability is maintained despite the softer composition.
Solution Approach 2:
The patent applies dynamics by incorporating a temperature-responsive polymer that dynamically adjusts the rubber's properties based on temperature conditions. This dynamic adaptation allows the rubber to be sufficiently soft for icy road conformity when cold, while maintaining appropriate drainage characteristics, thus resolving the static contradiction between softness and drainage capability.
3Object-generated harmful factors
If the tread rubber is made harder to improve water drainage, then water drainage capability improves, but handling stability on icy roads deteriorates
Solution Approach 1:
The patent resolves this contradiction by optimizing the rubber hardness parameters within a specific range (JIS-A hardness at 60°C of 58 or higher) rather than making the rubber excessively hard. This controlled parameter setting maintains sufficient water drainage capability while preserving adequate softness for road conformity on icy surfaces.
Solution Approach 2:
The patent uses composite materials with a temperature-responsive polymer that compensates for the relatively softer rubber composition. This polymer enhances the rubber's performance characteristics, allowing adequate water drainage to be achieved without sacrificing handling stability on icy roads, thus resolving the contradiction between drainage and icy-road performance.
4Reliability
If the rubber hardness at 0°C is made significantly lower than at 60°C to improve cold-weather performance, then handling stability on icy roads improves, but overall structural integrity deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the relationship between rubber hardness at different temperatures. Specifically, it limits the JIS-A hardness at 0°C to not more than 115% of the hardness at 60°C, preventing excessive softening at low temperatures that would compromise structural integrity, while still maintaining sufficient softness for road conformity on icy surfaces.
Solution Approach 2:
The patent uses composite materials with a temperature-responsive polymer that stabilizes the rubber's physical properties across temperature ranges. This polymer prevents the rubber from becoming too soft at low temperatures, thereby maintaining structural integrity while still allowing adequate softness for icy road performance, resolving the contradiction between cold-weather handling and overall strength.
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
Enhances handling stability on wet and icy roads by maintaining effective water drainage and road conformity through adaptive rubber hardness, improving overall tire performance.
Implementation Method 1
incorporating a temperature-responsive polymer composite to adjust hardness based on temperature changes
Data Source
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AI summary
Provided is a tire having excellent overall performance in terms of handling stability on wet roads when worn and handling stability on icy roads when worn. The present invention relates to a tire including a tread portion, the tread portion having at least one main groove continuously extending in the tire circumferential direction, the tread portion including a rubber having a hardness at 60°C of 58 or higher and a hardness at 0°C of not more than 115% of the hardness at 60°C, the tread portion having a S50/S0 ratio of more than 1, wherein S0 denotes the sea proportion (%) in the tread ground contact surface of the new tire, and S50 denotes the sea proportion (%) when the tread portion is worn until the depth of the main groove reaches 50% of that of the new tire.