Pneumatic Tire Tread Land Protrusion Ratio for Wear and Braking
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Solution Overview
Problem
Conventional pneumatic tires with center ribs protruding radially face severe uneven wear and lack improved wet braking performance, necessitating a solution that enhances both wear resistance and braking efficiency.
Innovation Solution
The tire features four or five circumferential grooves with specific land portions, where the correlation among the protrusion amounts of central, intermediate, and shoulder land portions from a virtual arc satisfies t1 < t2 < t3, with each land portion's outline protruding radially and formed of arcs with curvature smaller than the virtual arc, optimizing ground contact pressure and drainage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the center rib is shaped to protrude radially outward to improve steering stability and hydroplaning resistance, then steering stability and hydroplaning prevention are improved, but uneven wear of the center rib becomes severe
Solution Approach 1:
The patent changes the geometric parameters of the center rib by defining a specific protrusion amount ratio (0.3 ≤ t1/t2 ≤ 0.9) relative to the intermediate land portion. This controlled parameter adjustment allows the center rib to maintain sufficient protrusion for steering stability while limiting excessive protrusion that would cause severe uneven wear, thus resolving the contradiction between reliability and wear resistance.
2Reliability
If the center rib is shaped to protrude radially outward to improve hydroplaning prevention, then hydroplaning resistance is improved, but uneven wear of the center rib becomes severe
Solution Approach 1:
The patent optimizes the protrusion amount of the center rib by establishing a specific ratio relationship (0.3 ≤ t1/t2 ≤ 0.9) with the intermediate land portion. This parameter control ensures adequate hydroplaning resistance while preventing excessive protrusion that would lead to severe uneven wear, thereby resolving the contradiction between hydroplaning prevention and wear resistance.
3Ease of manufacture
If conventional tread patterns are used to achieve basic performance, then manufacturing simplicity is maintained, but wet braking performance is insufficient
Solution Approach 1:
The patent applies local quality by creating distinct land portions (shoulder, intermediate, and center land portions) with different protrusion characteristics. The center land portion has a controlled protrusion amount relative to the intermediate land portion, creating localized variations in the tread pattern that improve wet braking performance through better water evacuation and contact patch management, while maintaining overall manufacturing feasibility.
Data Source
AI summary
The pneumatic tire of this disclosure includes on a tread surface four or five circumferential grooves, and includes a pair of shoulder land portions, a pair of intermediate land portions, and one or a pair of central land portions partitioned thereon, wherein: in a tread widthwise cross sectional view at an unloaded condition when the tire is mounted to an applicable rim and applied with a prescribed internal pressure, when drawing a virtual arc R1 protruding to a tire radial outer side, of which a center of curvature is located on a tire equatorial plain, across four tread widthwise edges adjacent to the circumferential grooves of outlines of the pair of intermediate land portions, a correlation among each protrusion amount t1, t2 and t3 of outlines of the central land portions, the intermediate land portions and the shoulder land portions from the virtual arc R1 satisfies:t1<t2, and t3<t2.