Three-Layer Heavy-Duty Tire Tread for Wet Grip After Abrasion
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Solution Overview
Problem
Heavy-duty tires experience a deterioration in wet grip performance after abrasion due to the thermal aging of the cap rubber layer, which leads to increased rigidity and reduced followability to the road surface.
Innovation Solution
A heavy-duty tire design featuring a tread part with a three-layer structure, comprising a first layer as the tread surface, a second layer adjacent to the inner side of the first layer in the radial direction, and a third layer on the inner side of the second layer. Each layer is composed of a rubber composition with specific properties, including a high content of silica in the second layer to enhance hydrophilicity and a balanced silica content in the first layer for hydrophobicity and energy loss generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cap rubber layer is soft for good followability to road surface, then followability is improved, but rigidity of tread grounding surface becomes low and wet grip performance deteriorates
Solution Approach 1:
The tread structure is segmented into multiple layers where the second layer specifically provides the rigidity needed for wet grip maintenance after abrasion, while other layers can be optimized for followability, allowing independent optimization of these conflicting properties
Solution Approach 2:
The patent uses composite rubber compositions combining different rubber components (polybutadiene rubber, styrene-butadiene rubber) with varying silica contents to create layers with different mechanical properties, enabling the second layer to provide high rigidity through high silica content while other layers maintain softness for followability
2Reliability
If silica content in the second layer is increased to enhance hydrophilicity, then wet grip performance after abrasion is improved, but the overall structure complexity increases
Solution Approach 1:
The tread is segmented into three layers with the second layer specifically designed with high silica content (S2) to provide hydrophilicity and wet grip after abrasion, concentrating the complexity in a single functional layer rather than distributing it throughout the entire tread structure
Solution Approach 2:
High silica content is applied locally only in the second layer where it is most needed for wet grip maintenance after abrasion, while the first and third layers use different silica contents optimized for their specific functions, avoiding unnecessary complexity in areas where high silica is not required
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 improved wet grip performance after abrasion by maintaining contact with the road surface and enhancing braking performance, while also ensuring energy loss and hydrophobicity are effectively managed.
Implementation Method 1
a high content of silica in the second layer to enhance hydrophilicity
Implementation Method 2
each of the first layer, the second layer, and the third layer is composed of a rubber composition comprising a rubber component and a filler
Data Source
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AI summary
Provided is a heavy-duty tire comprising a tread part comprising circumferential grooves, wherein the tread part at least comprises three layers (11,12,13), and wherein Dt is 0.80 or more, t1/H is 0.90 or less, S1/S2 is less than 1.0, and S2×Dt is greater than 10.0, where a tire outer diameter is referred to as Dt, in m, a thickness of the first layer (11) is referred to as t1, in mm, a groove depth at a deepest part of the circumferential grooves is referred to as H, in mm, a content of silica based on 100 parts by mass of a rubber component in a rubber composition constituting the first layer (11) is referred to as S1, in parts by mass, and a content of silica based on 100 parts by mass of a rubber component in a rubber composition constituting the second layer (12) is referred to as S2, in parts by mass.