Pneumatic Tire Land Portion Width and Protrusion Design
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Solution Overview
Problem
Current pneumatic tire designs face challenges in maintaining steering stability on both dry and wet road surfaces due to reduced ground contact pressure and length, which affects drainage and contact with the road.
Innovation Solution
The tire features five land portions defined by four circumferential main grooves, with specific width and protrusion relationships, including a center land portion and outer/inner side middle and shoulder land portions, where the outer side middle and shoulder land portions protrude radially outward, optimizing ground contact length and pressure distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the land portion width is set wide to improve tread rigidity, then steering stability on dry road surfaces is improved, but ground contact pressure at the center decreases and ground contact length is reduced, causing steering stability to deteriorate
Solution Approach 1:
The patent applies local quality by creating different land portion widths at different locations: the center land portion has a smaller width (Wcc) while the outer side middle land portion has a larger width (Wco), with Wcc/Wco ≤ 1.2. This local differentiation allows the center to maintain higher ground contact pressure for steering stability while the outer portions provide sufficient tread rigidity through their larger width.
2Strength
If the land portion width is set wide to improve tread rigidity, then steering stability on dry road surfaces is improved, but ground contact length is reduced and contact with the ground is worsened
Solution Approach 1:
The patent differentiates land portion widths locally: the center land portion (smaller width Wcc) maintains longer ground contact length for better contact, while the outer side middle land portion (larger width Wco) provides tread rigidity. The ratio Wcc/Wco ≤ 1.2 ensures optimal balance between contact length and rigidity.
3Stress or pressure
If the ground contact pressure at the center decreases, then drainage performance deteriorates, but steering stability on wet road surfaces also deteriorates
Solution Approach 1:
The patent maintains higher ground contact pressure at the center land portion by giving it a smaller width (Wcc) compared to the outer side middle land portion (Wco). This localized pressure concentration improves both drainage performance and steering stability on wet road surfaces, while the outer portions compensate for tread rigidity through their larger width.
Data Source
AI summary
Steering stability performance on dry road surfaces and steering stability performance on wet road surfaces are improved.A land portion width Wcc of a center land portion (31) and a land portion width Wco of an outer side middle land portion (32) satisfy a relationship of Wcc<Wco. In addition, a ground contact surface (10) of each of the outer side middle land portion (32) and an outer side shoulder land portion (34) is formed to protrude toward an outer side in a tire radial direction with respect to a reference profile PRco, PRso, and a protruding amount Hco of the outer side middle land portion (32) and a protruding amount Hso of the outer side shoulder land portion (34) satisfy a relationship of Hco<Hso.