Crown Land Tire Tread Structure for Snow Grip and Dry Steering
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Solution Overview
Problem
Tires face a challenge in achieving excellent on-snow performance while maintaining steering stability on dry roads, as existing designs often compromise traction and braking performance on snow for dry road handling.
Innovation Solution
A tire design featuring a tread portion with a first crown circumferential groove having protrusions on its groove bottom and a crown land portion without drainage grooves, but with sipes, which enhances traction and braking on snow by creating a strong snow column and maintaining rigidity for improved steering stability on dry roads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If drainage grooves with opening width exceeding 2.0 mm and depth exceeding 2.0 mm are provided on the crown land portion, then water drainage performance is improved, but steering stability on dry roads deteriorates
Solution Approach 1:
The patent applies local quality by differentiating the groove characteristics across different regions of the tread. The crown land portion uses shallow grooves (depth ≤2.0 mm) with controlled opening widths to maintain rigidity and steering stability, while other regions can have deeper drainage grooves for water evacuation. This regional differentiation allows each area to optimize its function without compromising overall performance.
Solution Approach 2:
The patent changes the parameters of the grooves by specifying precise depth and width constraints (depth ≤2.0 mm, opening width controlled) for grooves on the crown land portion. These parameter adjustments ensure that the grooves provide sufficient water drainage while maintaining the structural rigidity needed for steering stability on dry roads, thus resolving the contradiction between drainage performance and steering stability.
2Stability of the object's composition
If the crown land portion is made rigid for steering stability, then steering stability on dry roads is improved, but traction and braking performance on snow deteriorates
Solution Approach 1:
The patent segments the tread into distinct functional zones: the crown land portion with controlled shallow grooves for steering stability, and other regions with deeper grooves and protrusions for snow traction. This segmentation allows the rigid crown land to provide steering stability while other segments provide snow performance through deeper snow engagement features.
Solution Approach 2:
The patent applies local quality by giving different groove characteristics to different regions. The crown land portion has shallow grooves (depth ≤2.0 mm) to maintain rigidity for steering stability, while other regions have deeper grooves and protrusions that engage snow effectively. This localized differentiation resolves the contradiction between rigid crown land for steering and snow traction capability.
3Force
If deeper grooves are provided to improve snow traction, then traction and braking performance on snow is improved, but the rigidity of the crown land portion decreases
Solution Approach 1:
The patent applies local quality by specifying that grooves on the crown land portion have depth ≤2.0 mm to maintain rigidity, while allowing deeper grooves in other regions for snow traction. This localized control of groove depth ensures the crown land remains rigid for steering stability while other areas provide sufficient snow engagement.
Solution Approach 2:
The patent segments the groove system into shallow grooves on the crown land portion for rigidity maintenance and deeper grooves elsewhere for snow traction. This segmentation allows deeper snow-engaging grooves to exist without compromising the rigidity of the crown land, as the deep grooves are confined to regions where rigidity is less critical for steering stability.
Data Source
AI summary
A tire includes a tread portion including a first tread edge, a second tread edge, a crown land portion arranged between the first tread edge and the second tread edge, and a first crown circumferential groove extending continuously in a tire circumferential direction adjacent to the crown land portion on a first tread edge side. The first crown circumferential groove includes a groove bottom having a plurality of protrusions projecting in a tire radial direction. The crown land portion is not provided with drainage grooves that have an opening width exceeding 2.0 mm at a ground contact surface of the crown land portion and a depth exceeding 2.0 mm of an area where a distance between two opposite groove walls thereof exceeds 2.0 mm. The crown land portion is provided with a plurality of sipes.