Agricultural Tyre Crown Reinforcement Bi-Modulus Elasticity
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Solution Overview
Problem
Agricultural tires with low pressure, such as IF and VF tires, experience reduced transverse and drift rigidities, leading to deterioration in transverse thrust and behavior under stress, which can be mitigated by stiffening the crown reinforcement with metal-reinforced layers, but this results in premature rupture of metallic reinforcements, reducing the tire's endurance.
Innovation Solution
The use of elastic metallic reinforcements with specific bi-module elastic behavior laws in the crown reinforcement, characterized by distinct extension and compression properties, including a first extension module up to 30 GPa and a second module at least twice that, along with a critical buckling deformation in compression of at least 3%, enhances the endurance of the crown reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If crown reinforcement is stiffened with metal-reinforced layers, then transverse thrust and behavior under stress are improved, but metallic reinforcements rupture prematurely
Solution Approach 1:
The invention changes the mechanical parameters of the metal reinforcement by specifying a bi-module elastic behavior law with a first extension module at most 30 GPa and a second extension module at least twice the first, along with a critical buckling deformation in compression of at least 3%. These parameter changes allow the crown reinforcement to maintain transverse thrust while preventing premature rupture, thereby resolving the contradiction between strength and reliability
Solution Approach 2:
The invention uses composite material structure by combining metal reinforcements with elastomeric material in a coated configuration. This composite approach allows the metal reinforcement to provide transverse thrust while the elastomeric coating and specific bi-module elastic behavior characteristics prevent premature rupture, thus resolving the contradiction between improved strength and maintained reliability
2Object-affected harmful factors
If low pressure tires are used, then soil compaction is reduced, but transverse and drift rigidities deteriorate
Solution Approach 1:
The invention changes the pressure parameter by specifying minimum recommended inflation pressures of 240 kPa for IF tires and 160 kPa for VF tires, which are lower than conventional tires. Simultaneously, it changes the mechanical properties of the crown reinforcement through bi-module elastic behavior to compensate for the reduced pressure, maintaining transverse rigidity while achieving reduced soil compaction
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 elastic metallic reinforcements improve the tire's ability to withstand compression/extension cycles, leading to increased endurance and lifespan, while maintaining the load-carrying capacity and traction performance required for agricultural vehicles.
Implementation Method 1
any law of elastic behavior in extension, called bi-module, comprising a first portion having a first extension module MG1 at most equal to 30 GPa, and a second portion having a second extension module MG2 at least equal to 2 times the first extension modulus MG1
Implementation Method 2
an elastomeric material, parallel to each other and forming, with a circumferential direction, an angle A at least equal to 10°
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
The subject of the present invention is a tyre (1) for an agricultural vehicle, comprising a crown reinforcement (3), comprising at least two crown layers (31, 32) that each comprise metallic reinforcers coated in an elastomeric material. According to the invention, every metallic reinforcer of a crown layer (31, 32) has a law describing elastic tensile behaviour, known as bi-modulus, comprising a first portion having a first tensile modulus MG1 at most equal to 30 GPa, and a second portion having a second tensile modulus MG2 at least twice the first tensile modulus MG1, and every metallic reinforcer of a crown layer (31, 32) has a law describing compressive behaviour, characterized by a critical compressive buckling deformation E0 at least equal to 3%.