Tyre Crown Reinforcement with Rubber Decoupling Layer
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Solution Overview
Problem
Current heavy vehicle tires face issues with wear regularity and endurance due to shear stresses and temperature rises, particularly in high-speed and long-distance travel, leading to irregular wear patterns and reduced performance over time.
Innovation Solution
A tire design featuring a radial carcass reinforcement with a crown reinforcement comprising two working layers separated by a layer of rubber compound, which includes a tread with longitudinal and transverse cutouts, and a layer of circumferential reinforcing elements to distribute shear stresses and maintain performance across the tire's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a layer of rubbery mixture is introduced between the ends of working layers to decouple them and limit shear stresses, then the endurance of the crown reinforcement is improved, but the manufacturing complexity increases
Solution Approach 1:
A layer of rubbery mixture is introduced as an intermediary substance between the ends of the working layers. This rubbery layer acts as a decoupling element that reduces shear stresses between the layers, thereby improving the endurance of the crown reinforcement while maintaining manufacturing feasibility through a relatively simple additive approach
Solution Approach 2:
The patent employs composite material construction by combining the rubbery mixture layer with the working layers of reinforcing elements. This composite structure allows the rubbery layer to absorb and distribute shear stresses, protecting the reinforcing elements from stress concentration at the ends, thus extending the service life of the crown reinforcement
2Reliability
If circumferential reinforcing elements are added to maintain load capacity and structure, then the tire performance is improved, but the manufacturing complexity and costs increase
Solution Approach 1:
The crown reinforcement is segmented into multiple functional layers: working layers of reinforcing elements for load-bearing, and circumferential reinforcing elements for structural stability. This segmentation allows each layer to perform its specific function optimally, improving overall tire reliability while enabling modular manufacturing processes
Solution Approach 2:
The circumferential reinforcing elements serve multiple functions: they maintain the load-carrying capacity of the tire, provide structural support to the crown area, and work in conjunction with the rubbery mixture layer to manage shear stresses. This multi-functionality justifies the added manufacturing complexity by delivering comprehensive performance benefits
3Productivity
If the tire is designed for high-speed and long-distance travel, then the kilometers travelled increase and wear decreases, but the endurance of the crown reinforcement is penalized due to temperature rise and shear stresses
Solution Approach 1:
The patent converts the harmful effect of shear stresses and temperature rises into a beneficial outcome by using the rubbery mixture layer as a stress-absorbing medium. This layer dissipates the thermal and mechanical stresses generated during high-speed, long-distance travel, preventing crack propagation in the crown reinforcement and thereby extending tire endurance despite increased operational demands
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 design achieves improved wear regularity and endurance by distributing shear stresses and maintaining performance, with reduced manufacturing complexity and costs, while also enhancing rolling resistance and fuel efficiency.
Implementation Method 1
A tire design featuring a radial carcass reinforcement with a crown reinforcement comprising two working layers separated by a layer of rubber compound, which includes a tread with longitudinal and transverse cutouts, and a layer of circumferential reinforcing elements to distribute shear stresses
Implementation Method 2
a layer of circumferential reinforcing elements to distribute shear stresses and maintain performance across the tire's lifespan
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a tyre including a crown reinforcement made up of at least two working crown plies (41, 43) of reinforcement elements and at least one ply (42) of circumferential reinforcement elements, a ply C of rubber mixture being arranged between the ends of the working crown plies. According to the invention, the tread has at least one longitudinal cut-out (8) and at least one transverse cut-out (10), the depth of said at least one longitudinal cut-out and at least one transverse cut-out, measured on a new tyre, being no less than 40 % of the thickness of the tread, the ratio of the width measured at the bottom of said longitudinal cut-outs to the width measured on the surface of the tread of said longitudinal cut-outs being strictly greater than 1.2, the ratio of the width measured at the bottom of said at least transverse one cut-out to the width measured on the surface of the tread on a new tyre of said at least one transverse cut-out being no lower than 1, the distance d between the axially narrowest end of the working ply and the working ply separated from the axially narrowest working ply by the ply C of rubber mixture being such that 1.1o < d < 2.2o, o being the diameter of the reinforcement elements of said at least one ply of circumferential reinforcement elements, and in a meridian plane, the thickness of the ply C of rubber mixture being substantially constant across the axial width between the axially inner end of the ply C and the end of the axially narrowest working ply. FIGURE 2.