Tyre Crown Reinforcement with Angled Layers for Endurance
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Solution Overview
Problem
Heavy-duty tires face challenges in endurance performance due to high operating temperatures and aggressive driving conditions, leading to increased wear and potential for cracks, while existing solutions to enhance endurance often result in increased tire mass and manufacturing costs.
Innovation Solution
A tire design with a radial carcass reinforcement featuring two working crown layers with specific angle orientations and a unique rubber composition, where the radially outermost layer forms a larger angle with the circumferential direction, reducing the number of layers in the crown reinforcement while maintaining or improving endurance, particularly on stony ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional layers of reinforcing elements are added to improve endurance, then tire durability is improved, but tire mass and manufacturing costs increase
Solution Approach 1:
The patent changes the angular parameters of the two working crown layers, with the first layer at angle α1 and the second layer at angle α2, where |α2| > |α1|. This parameter differentiation creates a staged tension uptake mechanism that improves impact resistance without adding protective layers, thus maintaining lower tire mass while enhancing durability
Solution Approach 2:
The patent employs a composite structure with two distinct working crown layers having different angular orientations and a specific rubber composition containing at least 60% by weight of specific polymers. This composite approach allows the material itself to provide enhanced durability through optimized mechanical properties rather than relying solely on additional reinforcement layers
2Weight of moving object
If the number of crown reinforcement layers is reduced to decrease weight, then tire mass is reduced, but endurance performance may be compromised
Solution Approach 1:
By optimizing the angular parameters α1 and α2 of the two working crown layers and ensuring |α2| - |α1| > 4°, the patent creates a staged tension uptake mechanism that delays peak tension during impacts. This parameter optimization allows the tire to maintain endurance performance with fewer layers, thus reducing tire mass
Solution Approach 2:
The patent applies local quality by creating different functional zones within the crown reinforcement through the two layers with distinct angular orientations. The first layer (α1) and second layer (α2) serve different mechanical functions in the impact sequence, with each layer optimized for its specific role in the staged tension uptake process
3Reliability
If high operating temperatures are endured to maintain performance, then tire durability decreases due to crack formation, but reducing performance adaptation is not an option
Solution Approach 1:
The patent uses a specialized rubber composition as a composite material containing at least 60% by weight of specific polymers (including polybutadiene and/or polyisoprene). This composite material exhibits superior resistance to thermal degradation and crack formation under high operating temperatures, maintaining tire durability without requiring performance reduction
Data Source
AI summary
The invention relates to a tyre of the heavy-duty vehicle type which is intended to be mounted on a 15° drop centre-type hollow rim. According to the invention, the two working crown layers (41, 42) are only present to form the crown reinforcement (4) over at least 40% of the width (L5) of the tread (5), the absolute value of the difference between the absolute values of the angles α2 and α1 being greater than 4°, α2 being greater than α1 in terms of absolute value, the mean angle α satisfying the relationship 20+164* exp(-L/100) < α < 23+164 exp(-L/100), and the reinforcing elements of the carcass reinforcement (2) being non-wrapped 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.