Tyre Crown Reinforcement with Differential Ply Angles
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Solution Overview
Problem
Heavy-duty tires face challenges in maintaining endurance performance while reducing overall mass and manufacturing costs, particularly under heavy loads and harsh driving conditions like stony ground, where existing solutions increase tire mass and costs by adding more reinforcing layers.
Innovation Solution
A tire design with a radial carcass reinforcement featuring two working crown layers with specific angle orientations and a unique distribution of reinforcing elements, where the radially outermost layer has a greater angle with the circumferential direction, reducing the number of layers while maintaining or improving endurance, and potentially eliminating the protective layer to reduce weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional layers of reinforcing elements are added to improve endurance performance, then the tire can better withstand shocks on stony ground, but the tire mass and manufacturing costs increase
Solution Approach 1:
The patent changes the angular parameter of reinforcing elements in the two working crown layers. The radially innermost layer has elements at angle α1 with the circumferential direction, while the radially outermost layer has elements at angle α2, where |α1| < |α2| and the difference exceeds 9°. This parameter differentiation optimizes the load distribution and tension uptake sequence during impacts, improving endurance without adding layers or mass.
Solution Approach 2:
The patent creates a composite structure with two distinct working crown layers having different reinforcing element orientations. This composite arrangement allows the inner layer to engage first during impacts (at the smaller angle), delaying tension uptake by the outer layer, thereby improving shock resistance without requiring additional protective layers or increasing overall tire mass.
2Strength
If the number of reinforcing layers is increased to improve shock resistance, then the tire can better handle heavy loads and harsh conditions, but the manufacturing complexity and costs increase
Solution Approach 1:
Instead of increasing the number of layers, the patent modifies the angular parameters of existing layers. The differentiated angles (|α1| < |α2| with difference > 9°) create optimal stress distribution and engagement sequence during shocks, achieving enhanced strength and shock resistance while maintaining simple two-layer construction and reducing manufacturing complexity.
3Reliability
If the angle of reinforcing elements is optimized to delay tension uptake, then the outer layer stress is reduced and endurance is improved, but the design complexity increases
Solution Approach 1:
The patent applies a specific parameter relationship (|α1| < |α2| with difference > 9°) to the reinforcing element angles. This simple yet precise parameter differentiation achieves the desired tension delay effect and reduced outer layer stress, improving endurance while maintaining design simplicity through a clear, quantifiable geometric rule.
Data Source
Figure 1
AI summary
The invention relates to a tyre, the aspect ratio H/L of which is strictly greater than 0.75, comprising a crown reinforcement (4) made up of two working crown layers (41, 42) of reinforcing elements. 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 of the tread (5), the absolute value of the difference between the absolute values of the angles a2 and a1 being greater than 9°, a2 being greater than a1 in absolute terms, the average angle a satisfying the relationship 14+131 *exp(-L/100) < a < 20+164 *exp(-L/100), and the utilization ratio of the breaking potential F2/FR2 of the radially outermost working layer (42) being less than 1/6.