Variable-Depth Lug Grooves for Tire Rolling Resistance and Traction
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Solution Overview
Problem
Pneumatic tires face a challenge in reducing rolling resistance without compromising traction characteristics, as narrowing grooves to reduce deformation improves rolling resistance but decreases drainage properties and traction on wet surfaces.
Innovation Solution
A pneumatic tire design featuring four or more circumferential main grooves with specific lug groove configurations, including central and shoulder lug grooves, sipes, and bent portions, optimized in width, depth, and orientation to balance rolling resistance and traction, ensuring effective drainage and contact with the road surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If grooves are narrowed to reduce deformation of land portions, then rolling resistance is reduced, but drainage properties are reduced and traction characteristics on wet surfaces deteriorate
Solution Approach 1:
The patent applies local quality by creating different groove depth zones within the lug groove structure. The first lug groove portion has a greater depth than the second lug groove portion, allowing the deeper section to provide drainage and traction functionality while the overall groove configuration maintains land portion rigidity. This localized variation in groove depth resolves the contradiction between reducing rolling resistance and maintaining traction characteristics.
2Loss of energy
If grooves are narrowed to reduce deformation of land portions, then rolling resistance is reduced, but drainage properties are reduced
Solution Approach 1:
The patent implements local quality by establishing different groove depths at different positions within the lug groove. The first lug groove portion extends deeper than the second lug groove portion, creating a localized deep drainage channel that effectively removes water from the contact patch while maintaining narrower overall groove dimensions. This resolves the contradiction between reduced rolling resistance and maintained drainage properties.
3Reliability
If groove depth of lug groove central portion is increased to improve drainage, then traction characteristics are improved, but rolling resistance increases due to greater land portion deformation
Solution Approach 1:
The patent applies local quality by creating a differentiated groove depth structure where the first lug groove portion has greater depth than the second lug groove portion. This localized deep groove provides sufficient drainage and traction functionality without requiring the entire groove structure to be deep, thereby maintaining land portion rigidity and reducing rolling resistance while still achieving improved traction characteristics.
Solution Approach 2:
The patent segments the lug groove into two distinct portions with different depths. The first lug groove portion serves as the primary drainage channel with greater depth, while the second lug groove portion provides secondary drainage and structural support. This segmentation allows optimization of drainage functionality without excessive overall groove depth, resolving the contradiction between traction improvement and rolling resistance reduction.
Data Source
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AI summary
In order to provide both reduction in rolling resistance and ensuring of traction characteristics of a pneumatic tire (1) in a compatible manner, in a land portion (20), a lug groove (40) is disposed extending in the tire width direction and opening to two circumferential main grooves (30) defining the land portion (20), a groove width (LW) of the lug groove (40) is in a range 0.5 mm ≤ LW ≤ 3.0 mm, the lug groove (40) includes a lug groove central portion (51) and lug groove edge portions (53) located on both sides of the lug groove central portion (51) in an extension direction of the lug groove (40), and a groove depth (Dc) of the lug groove central portion (51), a groove depth (De) of the lug groove edge portion (53), and a groove depth (Dg) of the circumferential main groove (30) have a relationship in a range 0.05 ≤ (Dc/Dg) ≤ 0.40 and in a range 0.60 ≤ (De/Dg) ≤ 1.00, and a width (RWc) of the lug groove central portion (51) in the tire width direction and a width (RWa) of the land portion (20) in the tire width direction have a relationship in a range 0.30 ≤ (RWc/RWa) ≤ 0.7.