Heavy-Duty Tire Tread Composition for Wet Grip and Rigidity
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Solution Overview
Problem
Heavy-duty tires face a continuous demand for improved wet grip performance, which existing technologies have not adequately addressed.
Innovation Solution
A heavy-duty tire design featuring a tread part with a rubber composition comprising isoprene-based rubber and silica filler, along with specific groove and sipe configurations, satisfies certain inequalities to enhance tread rigidity and flexibility, improving wet grip performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rubber compositions are used for heavy-duty tires, then the tire structure remains simple and manufacturing is easier, but wet grip performance is insufficient
Solution Approach 1:
The tread surface is segmented into multiple functional zones including circumferential main grooves, shoulder land parts, and sipe regions. This segmentation allows each zone to perform specific functions for optimizing wet grip performance while managing the complexity through systematic design
Solution Approach 2:
Different rubber composition formulations are applied to different regions of the tread. The shoulder land parts use compositions optimized for wet grip with specific silica and isoprene-based rubber content, while other regions may have different formulations to balance overall tire performance
2Reliability
If the tread rubber is made softer to improve wet grip, then wet grip performance improves, but tread rigidity decreases leading to poor durability
Solution Approach 1:
The rubber composition parameters are precisely controlled with specific ranges for silica content (40-80 parts by mass) and isoprene-based rubber content (60-100 parts by mass). The loss tangent at 0°C is optimized to 0.15-0.35 to achieve the right balance between softness for wet grip and rigidity for durability
Solution Approach 2:
The tread rubber uses a composite formulation combining silica filler with isoprene-based rubber. This composite material provides both the flexibility needed for wet grip performance and the structural integrity required for tread rigidity and durability
3Reliability
If silica content in the filler is increased to improve wet grip, then wet grip performance improves, but the rubber composition becomes more complex and harder to manufacture
Solution Approach 1:
The silica content is optimized within a specific range (40-80 parts by mass based on 100 parts by mass of isoprene-based rubber) to achieve wet grip improvement while maintaining manufacturability. This parameter optimization ensures the composition remains processable despite high silica content
Data Source
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AI summary
Provided is a heavy-duty tire comprising a tread part, the tread part comprising a rubber layer composed of a rubber composition, the rubber layer comprising a tread surface, the rubber composition comprising: a rubber component comprising a predetermined amount of an isoprene-based rubber; and a filler comprising a predetermined amount of silica, and wherein the content AIR, in % by mass, of the isoprene-based rubber in the rubber component, the content ASIL, in % by mass, of the silica in the filler, 0°C tan δ of the rubber composition, a total area SMG, in mm2, a pair of outermost circumferential main grooves present on a tread ground-contacting surface of the tread part, and a total area SLG, in mm2, of a shoulder lateral groove and a shoulder sipe that are present on the tread ground-contacting surface satisfy the predetermined inequalities.