Motor Vehicle Tyre Tread Design for Wet Grip and Stability
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Solution Overview
Problem
High-performance motor vehicle tires for supersport vehicles with large engine capacity and high power face challenges in maintaining grip and stability, especially on wet surfaces, while minimizing the number of grooves to avoid safety reductions.
Innovation Solution
A tire design featuring a central annular portion with a low void-to-rubber ratio and inclined grooves in the shoulder portions, where the first segment of each groove is shorter and precedes the second segment in the rolling direction, forming a concavity towards the equatorial plane, to enhance drainage and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of grooves in the tread band is reduced to improve grip and stability, then the void-to-rubber ratio decreases and contact surface area increases, but the drainage capability on wet surfaces deteriorates
Solution Approach 1:
The tread band is segmented into distinct functional zones: a central annular portion with minimal grooves for maximum contact and grip, and shoulder portions with inclined grooves for effective water drainage. This segmentation allows each zone to optimize its specific function without compromising the other.
Solution Approach 2:
Different regions of the tread band are assigned different groove densities and patterns. The central portion has a low void-to-rubber ratio with few grooves to maximize grip and stability, while the shoulder portions have higher void ratios with inclined grooves to provide drainage capability. Each local region is optimized for its specific operational requirement.
2Object-affected harmful factors
If inclined grooves are added to shoulder portions to improve drainage, then water evacuation capability increases, but the complexity of the tread pattern increases
Solution Approach 1:
The groove pattern exhibits asymmetric distribution across the tread band width. The central annular portion maintains a simple, minimal groove pattern for stability, while the shoulder portions feature asymmetrically oriented inclined grooves that efficiently channel water outward. This asymmetric design provides drainage functionality without uniformly increasing complexity across the entire tread.
Solution Approach 2:
Instead of distributing grooves uniformly across the entire tread band, the inclined grooves are concentrated only in the shoulder portions where drainage is most needed. This partial application of the groove pattern provides sufficient drainage capability while minimizing the overall complexity and maintaining simplicity in the central grip-critical region.
3Reliability
If the void-to-rubber ratio is kept low to maximize contact surface area, then grip and stability improve, but the drainage action effectiveness decreases
Solution Approach 1:
The tread band is divided into functional segments with different void-to-rubber ratios. The central annular portion maintains a low void-to-rubber ratio to maximize contact surface area for grip and stability, while the shoulder portions have elevated void ratios created by inclined grooves to provide effective drainage action. This segmentation resolves the contradiction by allowing both low and high void ratio regions to coexist in their respective optimal locations.
Solution Approach 2:
The void-to-rubber ratio is optimized locally for each region's function. In the central contact-critical zone, the ratio is kept low to maximize grip. In the shoulder drainage zones, the ratio is increased through inclined grooves to enhance water evacuation. Each local region's quality is tailored to its specific operational role.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The tire achieves improved grip, stability, and wear evenness on both dry and wet surfaces, particularly during high acceleration/deceleration and bending, while maintaining safety by reducing groove impact frequency and increasing contact surface area.
Implementation Method 1
increasing the effectiveness of the draining action in front tyres
Implementation Method 2
the first grooves comprise at least one first segment and at least one second segment which is inclined with respect to said first segment so as to form a concavity directed towards the equatorial plane
Implementation Method 3
the tyres shall have very good features as regards the grip to the ground, so as to be able to effectively transfer the high traction torque to the ground
Implementation Method 4
a stable behaviour of the tyre indicates its capacity to effectively dampen perturbations transmitted by the unevenness of the road surface
Data Source
AI summary
A motor vehicle tire, particularly for front wheels of motor vehicles, has a tread extending around an axis of rotation and includes a central annular portion which straddles an equatorial plane and two annular shoulder portions arranged on axially opposite sides of the central annular portion. The tread band has a void-to-rubber ratio of less than 10%, and the central annular portion has an axial extension less than 40% of the axial development of the tread band and includes at least a pair of first grooves extending substantially longitudinally on opposite sides of the equatorial plane. Each shoulder portion has an axial extension less than 35% of the axial development of the tread band and includes a plurality of second grooves extending substantially transversally forming an average angle with the equatorial plane of more than 90°. The central annular portion has a void-to-rubber ratio more than 0.15 and the first grooves include at least one first segment and at least one second segment which is inclined with respect to the first segment so as to form a concavity directed toward the equatorial plane. The first segment of each first groove is shorter than the second segment and precedes the second segment in the tire rolling direction.