Heavy-duty Tire Tread Pattern and Belt Width Ratio for Off-Road Durability
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Solution Overview
Problem
Heavy-duty pneumatic tires face challenges in maintaining traction performance and preventing belt edge separation, especially in large tires used for off-road vehicles like dump trucks, where increased ground contact pressure strains the belt layers, leading to separation.
Innovation Solution
The tire features a unique tread pattern with center lug grooves, shoulder lug grooves, and circumferential primary and secondary grooves, along with a laminated belt structure and specific orientations of reinforcing cords, which disperses stress and enhances tread rigidity and belt durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the widths of blocks in the tread central region are increased to improve traction performance, then ground contact pressure locally increases at block edges, but this applies great force to belt ends and increases strain between belt layers, leading to separation
Solution Approach 1:
The patent applies local quality by varying the groove widths at different locations. The circumferential primary grooves have different widths at their ends compared to their central portions, with the end widths specifically designed to be smaller. This local variation in groove geometry redistributes the ground contact pressure, reducing the localized high pressure at block edges while maintaining adequate traction performance across the tread surface.
Solution Approach 2:
The patent segments the circumferential primary grooves into different width zones - narrower ends and wider central portions. This segmentation allows different regions of the same groove structure to serve different functions: the narrower ends reduce stress concentration at belt locations, while the wider central portions maintain traction effectiveness in the tread center region.
2Productivity
If larger tires are used for off-road vehicles to improve traction, then the tire size increases, but the increased ground contact pressure strains belt layers more, leading to separation
Solution Approach 1:
The patent applies local quality by varying the groove widths at different locations. The circumferential primary grooves have different widths at their ends compared to their central portions, with the end widths specifically designed to be smaller. This local variation in groove geometry redistributes the ground contact pressure, reducing the localized high pressure at block edges while maintaining adequate traction performance across the tread surface.
Data Source
AI summary
A heavy-duty pneumatic tire includes a tread pattern including center lug grooves, shoulder lug grooves, a pair of circumferential primary grooves formed in wave-like shapes by alternately connecting ends of the center lug grooves and ends of the shoulder lug grooves and having a smaller width than the width of the shoulder lug grooves, center blocks defined by the center lug groove and the circumferential primary grooves, and a circumferential secondary groove extending in the tire circumferential direction so as to divide regions of the center blocks. The belt portion includes two or greater pairs of belts. The ratio of the width W8 of a belt having a smaller width in each of the belt pairs to the width W7 of a belt having a greater width is 0.75 or greater and 0.90 or less.