Tire Crown Reinforcement with Rubber Interlayer
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Solution Overview
Problem
Current heavy-duty tires face challenges in maintaining endurance and wear resistance due to shear stresses and increased operating temperatures, leading to cracks and reduced performance, especially under high-speed and long-distance conditions.
Innovation Solution
A tire design featuring a radial carcass reinforcement with unequal axial widths working crown layers, a layer of rubber compound between the crown layers, and a second polymer compound layer extending to the tread, along with circumferential reinforcing elements, which helps in decoupling shear stresses and enhancing cornering stiffness while maintaining endurance and reducing manufacturing and storage complexities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a layer of rubber compound is placed between the ends of working crown layers to reduce shear stresses, then the endurance of the crown reinforcement is improved, but the device complexity and manufacturing complexity increase
Solution Approach 1:
A layer of rubber compound is introduced as an intermediary element between the working crown layers and the tread. This rubber layer acts as a stress-distributing medium that reduces shear stresses at the ends of the working layers, thereby improving endurance without requiring fundamental changes to the tire structure
Solution Approach 2:
The patent employs composite material construction by combining rubber compound layers with reinforcing elements (such as steel cords or fabric plies) in the crown reinforcement structure. This composite approach allows the rubber layer to provide stress distribution while the reinforcing elements maintain structural integrity, achieving improved durability without excessive complexity
2Reliability
If the axial width of working crown layers is reduced to improve wear resistance, then the wear resistance is improved, but the cornering stiffness decreases
Solution Approach 1:
The patent applies different properties to different regions of the crown reinforcement. The working layers have optimized axial widths for wear resistance, while the protective layers and rubber compound layers provide enhanced strength and stiffness in critical areas. This local differentiation allows wear resistance to be improved without sacrificing cornering stiffness
Solution Approach 2:
By using composite material construction with multiple layers having different functions and properties, the patent achieves a balance between wear resistance and cornering stiffness. The composite structure allows each layer to be optimized for its specific function while contributing to the overall performance
3Reliability
If multiple layers of rubber compound with different moduli are used to maintain performance, then the endurance and cornering stiffness are maintained, but the manufacturing precision and device complexity increase
Solution Approach 1:
The patent utilizes parameter changes in the rubber compound layers, specifically varying the elastic modulus of different rubber layers to achieve optimal performance. By carefully selecting and positioning layers with different moduli, the patent maintains endurance and cornering stiffness while managing manufacturing complexity through systematic parameter optimization
Data Source
AI summary
Tire comprising a crown reinforcement formed of two working crown layers having unequal axial widths, layer C of rubber compound between ends of the working crown layers, layer S of polymer compound in contact with at least one working crown layer and in contact with the carcass reinforcement and the crown reinforcement comprising a layer of circumferential reinforcing elements arranged radially between two working crown layers. Distance d between the end of the axially narrowest working layer and the working layer separated from the axially narrowest working layer by the layer C is 1.1ø<d<2.2ø, ø being the diameter of the reinforcing elements of the layer of circumferential reinforcing elements, in a meridian plane. The thickness of layer C is substantially constant and the complex dynamic shear modulus G*, measured at 10% and 60° C. on the return cycle, of layer S is greater than 1.35 MPa.