Pneumatic Tire Tread Rib Geometry for Uneven Wear Resistance
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Solution Overview
Problem
Conventional pneumatic tires face challenges in achieving enhanced uneven-wear resistance, particularly in heavy-duty applications where uneven wear is exacerbated by high loads and lateral force slipping.
Innovation Solution
The pneumatic tire design incorporates a specific radial construction with circumferential main grooves and ribs, optimizing contact pressure distribution by forming a convex contact patch on the outer side for center ribs and inner side for shoulder ribs, along with optimized groove widths, rib widths, and rubber hardness, which increases the modulus of rigidity and reduces slipping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact patch of shoulder rib is formed with convex on inner side and center rib with convex on outer side, then contact pressure distribution is optimized and uneven wear is reduced, but the structural complexity of tread portion increases
Solution Approach 1:
The patent applies local quality by differentiating the contact patch geometry between center ribs and shoulder ribs. Center ribs have convex contact patches on the outer side while shoulder ribs have convex contact patches on the inner side. This localized differentiation optimizes contact pressure distribution in different regions of the tread, reducing uneven wear while maintaining a manageable structural complexity through region-specific design optimizations.
2Strength
If the groove width ratio GW/TW is optimized within 0.15-0.20, then tread rubber gauge on belt layer is thickened and stiffness of shoulder region is increased, but the groove width design constraints become more stringent
Solution Approach 1:
The patent employs parameter changes by optimizing the groove width ratio GW/TW within a specific range of 0.15-0.20. This parameter optimization achieves multiple benefits: thickening the tread rubber gauge on the belt layer, increasing the stiffness of the shoulder region, and reducing variations of tread rubber during tire rotation. The constrained parameter range provides a balanced solution that meets performance requirements while maintaining manufacturing feasibility.
3Reliability
If the distance PW/(TW/2) is optimized within 0.5-0.65, then the position of inflection point is optimized for enhanced uneven-wear resistance, but the geometric constraints on tread design become more restrictive
Solution Approach 1:
The patent applies parameter changes by optimizing the dimensionless parameter PW/(TW/2) within the range of 0.5-0.65, where PW is the distance from tire equator surface to the inflection point and TW is the tread width. This optimization positions the inflection point of the tread radius to enhance uneven-wear resistance. The standardized parameter approach provides a systematic method for geometric design that balances performance optimization with design flexibility.
Data Source
AI summary
A pneumatic tire has a plurality of circumferential main grooves extending in a tire circumferential direction and a plurality of ribs partitioned by the circumferential main grooves in a tread portion. When viewing a cross-section from a tire meridian direction a contact patch of the center ribs is formed from a smooth curved line forming a convex on an outer side in a tire radial direction and a contact patch of the shoulder rib is formed from a smooth curved line forming a convex on an inner side in the tire radial direction. The curved line of the center ribs and the curved line of the shoulder rib have a point of intersection. A distance between an extended line of the curved line of the center ribs and the curved line of the shoulder rib increases from the point of intersection towards an outer side in a tire width direction.