Heavy-Duty Tyre Sidewall and Crown Reinforcement Design
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Solution Overview
Problem
Heavy-duty tires face challenges in maintaining endurance and resistance to shocks and curbs, particularly when traveling on aggressive ground, due to increased mass and manufacturing costs associated with additional reinforcing layers, which can lead to degradation in performance under high-speed and heavy-load conditions.
Innovation Solution
A tire design featuring a radial carcass reinforcement with two working crown layers forming angles greater than 8° with the circumferential direction, accompanied by a layer of circumferential reinforcement elements, anchored in beads with a specific profile that reduces the number of layers in the crown reinforcement while maintaining or improving endurance, specifically through the use of unhooped metal cords with a rubber sheath and a unique tread and sidewall profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If additional reinforcing layers are added to the crown reinforcement, then resistance to shocks and curbs is improved, but tire mass and manufacturing costs increase
Solution Approach 1:
The patent changes the geometric parameters of the crown reinforcement by specifying precise angle ranges for the two working layers (α1 between 10°-45° and α2 between 45°-90° relative to the circumferential direction). This angular configuration optimization allows the reinforcement structure to better resist shock and curb forces without requiring additional layers, thereby maintaining strength while controlling weight.
Solution Approach 2:
The patent employs a composite reinforcement structure combining two distinct working layers with different orientations and characteristics. The first working layer uses cables at a shallower angle while the second working layer uses cables at a steeper angle, creating a composite structure that distributes stress more effectively and provides superior shock resistance compared to single-layer designs.
2Strength
If additional reinforcing layers are added to the crown reinforcement, then resistance to shocks and curbs is improved, but manufacturing costs increase
Solution Approach 1:
The patent optimizes the manufacturing process by defining specific angular parameters for the two working layers that can be achieved through standard manufacturing techniques. The angle ranges (α1: 10°-45°, α2: 45°-90°) are designed to be compatible with conventional cable laying and vulcanization processes, avoiding the need for complex or expensive manufacturing equipment while still achieving superior shock resistance.
3Weight of moving object
If the number of crown reinforcement layers is reduced, then tire mass and manufacturing costs decrease, but endurance and resistance to shocks may degrade
Solution Approach 1:
The patent achieves weight reduction while maintaining reliability by optimizing the angular parameters of the two working layers. The specific angle ranges ensure that the reinforcement structure effectively resists shock and curb forces, providing sufficient endurance with fewer layers compared to conventional single-layer designs.
Solution Approach 2:
The patent uses a composite two-layer structure where each layer serves a specific functional purpose. The first working layer (shallower angle) and second working layer (steeper angle) work together synergistically to provide comprehensive shock and curb resistance, achieving reliable endurance performance with reduced overall mass.
4Ease of operation
If the angle between working layers is optimized, then dynamic properties and maneuverability are enhanced, but structural complexity increases
Solution Approach 1:
The patent enhances maneuverability and dynamic properties by optimizing the angular parameters of the two working layers. The angle ranges (α1: 10°-45°, α2: 45°-90°) are specifically selected to improve the tire's response to steering inputs and dynamic loads. Despite these optimizations, the structure remains relatively simple as it only adds one additional layer compared to conventional designs, avoiding excessive structural complexity.
Data Source
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AI summary
The invention relates to a tyre having a radial carcass reinforcement made up of a single layer of reinforcing elements which is anchored in each of the beads by being turned up around a bead wire, reinforced by a stiffener. According to the invention, the two working crown layers are only present to form the crown reinforcement across at least 75% of the width of the tread, the absolute value of the difference between the absolute values of the angles α2 and α1 being greater than 7°, α2 being greater than α1 in terms of absolute value, the mean angle α satisfying the relationship 13+131*exp(- L/100) < α < 28+110*exp(-L/100), the reinforcing elements of the carcass reinforcement being cords that exhibit, in the test known as the permeability test, a flow rate less than 20 cm3/min, a rubber compound being present within the cords and, in the sidewall of the tyre, the profile of the outer surface of the tyre being at a constant distance from the carcass reinforcement layer between the points F and A, and meeting the outer surface of the bead at the point C, forming two successive circular arcs.