Siped Off-Road Tire Tread Segmentation for Wear Resistance
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Solution Overview
Problem
Tires for heavy-load off-road vehicles, particularly those used in civil engineering works, experience high stress and uneven wear when twinned on a rear axle, especially during cornering maneuvers, leading to reduced tread stiffness and increased wear rates.
Innovation Solution
A tread pattern design featuring three main circumferential grooves with intermediate and edge ribs, where intermediate ribs have fine grooves oriented transversely or obliquely, and edge ribs have wide grooves, to enhance contact pressure and reduce slippage, maintaining grip and wear performance across varying load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the tread width is increased to accommodate heavy loads, then the load-bearing capacity is improved, but the tread experiences higher stress and uneven wear during cornering maneuvers
Solution Approach 1:
The tread is segmented into multiple ribs (central rib, intermediate ribs, and edge ribs) separated by grooves. This segmentation distributes the heavy load across multiple contact points, reducing stress concentration on any single rib while maintaining overall load-bearing capacity. The grooves allow independent deformation of each rib, improving flexibility and reducing uneven wear during cornering maneuvers.
Solution Approach 2:
Different regions of the tread are given different structural characteristics: the central rib has a specific width ratio (0.15-0.30 times tread width) optimized for load distribution, while edge ribs have different dimensions for lateral stability. The grooves have varying depths and widths in different zones to locally optimize for either water evacuation, heat dissipation, or structural flexibility depending on the operational requirements of that specific region.
2Reliability
If the tread structure is made more complex to improve grip, then the traction performance is improved, but the manufacturing complexity increases
Solution Approach 1:
The grip enhancement is achieved through segmentation into distinct rib structures with grooves between them, rather than through complex surface patterns. Each rib acts as an independent gripping element, and the grooves provide flexibility. This segmented approach achieves good grip through simple geometric forms that are easier to manufacture than complex continuous patterns.
Solution Approach 2:
The invention optimizes grip by carefully controlling dimensional parameters: the central rib width ratio (0.15-0.30), the number and spacing of intermediate ribs, and groove depths. By adjusting these parameters within specific ranges, the tread achieves optimal grip performance across different operating conditions without requiring complex structural features, maintaining manufacturing simplicity.
3Reliability
If the grooves are made deeper to improve water evacuation, then the water channeling capability is improved, but the tread stiffness is reduced
Solution Approach 1:
The groove system is segmented into multiple grooves separated by ribs, with each groove contributing to water evacuation. The ribs act as structural stiffeners between the grooves, maintaining overall tread stiffness even when grooves are deep. This segmentation allows the grooves to be deep enough for effective water channeling while the ribs preserve the necessary structural rigidity.
Solution Approach 2:
The groove depth and width are optimized locally: grooves are deepest in regions where water evacuation is most critical, while ribs are positioned and dimensioned to provide structural support where stiffness is needed. This local optimization allows deep grooves for water channeling without compromising overall tread stiffness, as the ribs compensate for the stiffness loss in the grooved regions.
Data Source
AI summary
Tread (10) for a tire of an off-road vehicle. Total width Wt of the tread is greater than 600 mm and has at least three circumferential main grooves (1, 2, 3, 4) at least 60 mm deep that divide the tread into intermediate ribs (51, 52, 53) and edge ribs (8). The edge ribs have a width≤0.25 Wt. At least one of the intermediate ribs (51, 52, 53) has fine grooves (61, 62, 63) of depth H1 delimiting blades of material (71, 72, 73) of mean width B1<2H1. Grooves (61, 62, 63) are oriented in the axial direction of the tire. Each intermediate rib (51, 52, 53) has a mean width≤0.25 Wt and ≥0.75 Ht (thickness of material to be worn away). Grooves, (61, 62, 63) have, over a height H12 at least equal to 65% of H1, a width≤ to the value obtained from 0.04√{square root over (B1·H1)}.