Heavy-Duty Tire Tread Pattern and Rubber Composition for Wear Resistance
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Solution Overview
Problem
Heavy-duty tires face challenges in achieving optimal uneven wear resistance due to insufficient stiffness in crown and middle land portions, leading to uneven wear during tire operation, especially under wet conditions.
Innovation Solution
A heavy-duty tire design featuring a tread pattern with predetermined crown main grooves, shoulder main grooves, crown and shoulder land portions, and shoulder lateral grooves, combined with a rubber composition containing 90% or more isoprene-based rubber and specific carbon black blending, which enhances stiffness and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the tread pattern is designed with standard crown and middle land portions, then the tire structure is simple and easy to manufacture, but the stiffness of the crown land portions and middle land portions is insufficient, leading to uneven wear
Solution Approach 1:
The tread pattern is segmented into multiple functional zones: crown main grooves dividing the crown land into multiple portions, shoulder main grooves separating middle land portions, and shoulder lateral grooves in the shoulder land portions. This segmentation creates distinct structural units that can be independently optimized for stiffness and wear resistance while maintaining overall tire performance.
Solution Approach 2:
Different regions of the tread are assigned different structural characteristics: the crown land portions have specific width ratios (Wc/Wm between 0.8-1.2) to optimize central stiffness, the middle land portions have controlled widths (Wm) to balance lateral stability, and the shoulder land portions include lateral grooves of specific lengths (Ls) to enhance edge stiffness. Each region's geometry is locally optimized for its specific functional requirements.
2Reliability
If conventional rubber composition is used, then the manufacturing cost is lower and processing is easier, but the uneven wear resistance is insufficient under wet conditions
Solution Approach 1:
The rubber composition is formulated as a composite system combining isoprene-based rubber (providing elasticity and wet grip) with styrene-butadiene rubber (providing abrasion resistance and structural stability). This composite material approach leverages the complementary properties of different rubber types to achieve superior uneven wear resistance while maintaining processability and cost-effectiveness.
Solution Approach 2:
The rubber composition parameters are precisely controlled: isoprene-based rubber content is set at 30-80 parts per 100 parts total rubber to optimize the balance between wet performance and wear resistance, while styrene-butadiene rubber content is controlled at 20-70 parts. These parameter specifications ensure consistent uneven wear resistance across production batches without complicating the manufacturing process.
Data Source
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Figure 2
AI summary
A heavy-duty tire having excellent uneven wear resistance is provided. The heavy-duty tire includes a tread portion having a pair of crown main grooves 4 continuously extending in a tire circumferential direction and provided at both sides of a tire equator, and a pair of shoulder main grooves 5 provided between the crown main grooves and tread edges Te. The tread portion has one crown land portion 8, a pair of middle land portions 7 and a pair of shoulder land portions 9. At least one of the shoulder land portions 9 has shoulder lateral grooves 29 extending in a tire axial direction. Wc, Wm and WS satisfy the following formula (1). A maximum length Lsm in the tire axial direction (mm) of the shoulder lateral grooves 29 and Ws satisfy the following formula (2). A total length Lst in the tire axial direction (mm) of the shoulder lateral grooves 29 and a tire outer diameter H (mm) satisfy the following formula (3). The tread portion containing 90% by mass or greater of an isoprene-based rubber, and carbon black having an average particle diameter of not greater than 20 nm and/or a cetyltrimethylammonium bromide adsorption specific surface area of not less than 130 m2/g