Tire Tread with Variable Sipe Density and Round Crown
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Solution Overview
Problem
Tires face a compromise between maintaining hydroplaning performance, dry braking performance, and wear resistance, as designs that improve one aspect often adversely affect the others, such as square footprints optimizing wear leading to poor hydroplaning and round footprints enhancing hydroplaning but reducing wear life.
Innovation Solution
A tire tread with variable sipe density, where the central region has a higher sipe density and the shoulder regions have a lower sipe density, combined with a profiled undertread and a third breaking belt for enhanced structural stiffness, allowing for a rounder footprint that maintains equivalent wear rates and improves hydroplaning performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a square footprint is used in the contact patch, then wear life is improved through equivalent rib length and homogeneous rib stiffness, but hydroplaning performance deteriorates due to poor water evacuation
Solution Approach 1:
The tread design implements different sipe densities in different regions: central ribs have higher sipe density (5-9mm spacing) while shoulder ribs have lower sipe density (15-35mm spacing). This local differentiation allows the central portion to maintain flexibility for water evacuation while shoulders provide structural support for wear resistance, resolving the contradiction between hydroplaning performance and wear life.
2Object-affected harmful factors
If a rounder footprint is used to improve hydroplaning performance through better water evacuation, then wear performance deteriorates due to unequal rib lengths causing uneven stress distribution
Solution Approach 1:
The patent applies local quality by creating region-specific tread elements with differentiated properties. Central tread elements have higher sipe density for flexibility and water channeling, while shoulder elements have lower sipe density and greater thickness for stress distribution and wear resistance. This localized differentiation enables the round footprint to achieve both hydroplaning performance and even wear.
Solution Approach 2:
The tread is segmented into central and shoulder regions with distinct design characteristics. Central ribs focus on hydroplaning resistance with higher sipe density, while shoulder ribs focus on wear resistance with lower sipe density and structural reinforcement. This segmentation allows each region to optimize its function without compromising the other.
3Object-affected harmful factors
If more void is added to the tread through additional longitudinal grooves to improve hydroplaning performance, then contact surface area decreases leading to greater X stresses and quicker wear
Solution Approach 1:
Rather than uniformly increasing void across the entire tread, the patent applies siping selectively: central ribs receive higher sipe density (5-9mm) for water evacuation while shoulder ribs receive lower sipe density (15-35mm) to maintain contact surface area. This localized approach provides hydroplaning performance without sacrificing overall contact area and wear resistance.
4Duration of action of stationary object
If a higher modulus compound is used to improve wear resistance, then dry braking performance deteriorates
Solution Approach 1:
The patent addresses this contradiction through structural design rather than compound modification. By optimizing sipe density distribution and tread element geometry, the design achieves wear resistance through even stress distribution while maintaining dry braking performance through adequate contact surface area. This avoids the need to change compound properties that would compromise dry braking.
Data Source
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AI summary
This invention relates generally to tires having treads that have a configuration and/or properties for maintaining hydroplaning performance, dry braking performance and improved wear resistance, and, more specifically, to a tire that has a tread that has a variable sipe density, i.e a higher sipe density in its central portion and a lower sipe density in its shoulder portions, as well as a round crown with a predetermined inflated profile droop. Another embodiment of the present invention further includes the addition of a member that provides more structural stiffness across the crown. of a tire, such that better compromises between hydroplaning, dry braking, and wear performances can be obtained.