Tire Tread Longitudinal Cut Geometry and Reinforcement
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Solution Overview
Problem
Current heavy-duty tires face issues with wear regularity in the transverse direction and rolling resistance, particularly when equipped with longitudinal cuts featuring hidden hollows, leading to irregular wear patterns and increased fuel consumption.
Innovation Solution
A tire design with a radial carcass reinforcement including a crown reinforcement of working layers with calendered rubber mixtures, a layer of circumferential reinforcing elements, and longitudinally oriented cutouts with specific depth and width ratios, along with a layer of circumferential reinforcing elements to control deformation and maintain cohesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If longitudinal cuts with hidden hollows are introduced in the tread to improve water evacuation and grip, then grip performance is improved, but wear regularity in the transverse direction deteriorates
Solution Approach 1:
The patent modifies the geometric parameters of the longitudinal cuts by constraining the depth to be between 0.2 and 0.8 times the tread thickness and the width at the bottom to be between 0.5 and 2 times the width at the surface. These parameter changes optimize the balance between water evacuation capability and wear regularity, preventing excessive deformation while maintaining grip performance.
Solution Approach 2:
The patent introduces circumferential reinforcing elements specifically positioned beneath the longitudinal cuts in the tread area. This local reinforcement provides targeted support where deformation occurs during rolling, maintaining wear regularity in the critical cutout regions without compromising the overall grip performance provided by the cutouts.
2Ease of manufacture
If less favorable rubber mixtures are used to reduce costs, then manufacturing cost is reduced, but rolling resistance increases leading to higher fuel consumption
Solution Approach 1:
The patent employs composite material construction with circumferential reinforcing elements (such as steel cords or fabric layers) embedded within the tread and working layers. This composite structure compensates for the inferior rolling resistance properties of cost-reduced rubber mixtures, maintaining acceptable fuel consumption levels while allowing the use of less expensive rubber compounds.
Solution Approach 2:
The patent optimizes the physical and chemical parameters of the rubber mixtures by specifying precise compositional ranges and processing conditions. This allows the use of less favorable (cheaper) rubber mixtures while maintaining their rolling resistance properties within acceptable limits through careful parameter control during compounding and curing.
3Productivity
If the depth of longitudinal cutouts is increased to improve water evacuation, then water evacuation capability is improved, but deformation control and wear regularity deteriorate
Solution Approach 1:
The patent establishes an optimal parameter range for cutout depth (0.2 to 0.8 times tread thickness) that balances water evacuation capability with deformation control. This parameter optimization ensures sufficient depth for effective water channeling while preventing excessive depth that would cause unstable deformation and irregular wear patterns during tire operation.
Solution Approach 2:
The circumferential reinforcing elements act as an intermediary structural support beneath the longitudinal cutouts. These elements provide mechanical stability to the tread structure, preventing excessive deformation in the deeper cutout regions while allowing the cutouts to maintain their water evacuation function. The reinforcing elements mediate between the deep cutouts and the tread structure.
4Manufacturing precision
If circumferential reinforcing elements are added to control deformation, then wear regularity is improved, but device complexity increases
Solution Approach 1:
The patent segments the tire structure by introducing circumferential reinforcing elements as distinct layers within the tread and working layers. This segmentation allows the reinforcing elements to be positioned strategically beneath longitudinal cuts and in specific radial locations, providing targeted deformation control without requiring complete structural redesign of the entire tire.
Solution Approach 2:
The circumferential reinforcing elements serve multiple functions simultaneously: they control deformation in longitudinal cutout regions, maintain wear regularity across the tread, and provide structural support for the working layers. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in overall device complexity.
Data Source
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AI summary
The invention relates to a tire including a crown reinforcement formed of at least two working crown layers (41, 43) of reinforcing elements and at least one layer (42) of circumferential reinforcing elements. In accordance with the invention, the tread has at least one longitudinally oriented cut (8), the depth, measured on a new tire, of said at least one longitudinally oriented cut being greater than or equal to 40% of the thickness of the tread, the ratio of the width measured at the bottom of said at least one longitudinally oriented cut to the width measured on the surface of the tread of said at least one longitudinally oriented cut being strictly greater than 2, the tensile modulus of elasticity at 10% elongation of at least one calendering layer of at least one working crown layer being greater than 9 MPa, and the maximum value of tan(8), denoted tan(8)max, of said at least one calendering layer of at least one working crown layer being less than 0.100.