Tyre Carcass Ply Strip Elements for Load Distribution
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Solution Overview
Problem
High-performance tires for ultra-high performance cars face critical stress and deformation issues due to high loads, leading to reduced rigidity and instability, especially in the sidewall areas, which affects handling, braking efficiency, and ride comfort.
Innovation Solution
The use of strip-like elements with reduced thickness lateral portions and smaller average diameter end cords to minimize the moment of inertia and maintain structural uniformity, ensuring that the tension in both ply layers remains effective under extreme loading conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If strip-like elements with overlapping joints are used to form carcass plies, then the tire structure gains continuity and strength, but the joint thickness increases creating a moment of inertia that causes neutral axis shift and reduces sidewall rigidity
Solution Approach 1:
The patent applies local quality by creating a transition zone in the strip-like elements where the cord density and thickness are locally modified. Specifically, the end portions of the strips have reduced cord density compared to the central portions, creating a gradual thickness transition that minimizes the moment of inertia at joints while maintaining overall structural integrity. This local modification resolves the contradiction by allowing continuous strength without creating destabilizing thick joints.
Solution Approach 2:
The patent changes physical parameters of the strip-like elements, specifically the cord density and thickness distribution along the strip length. By reducing cord density in end portions and maintaining higher density in central portions, the patent creates a parameter gradient that optimizes the moment of inertia distribution. This parameter change allows the joint regions to have reduced thickness variation, preventing neutral axis shift while maintaining the strength needed for carcass ply continuity.
2Force
If the carcass structure is reinforced to handle high loads, then the tire can withstand high-performance driving conditions, but the sidewall areas experience increased stress and deformation reducing handling precision
Solution Approach 1:
The patent segments the cord structure within strip-like elements by creating distinct regions with different cord densities. The central portions have higher cord density for load bearing, while end portions have reduced cord density for flexibility. This segmentation allows different parts of the same structural element to serve different functions: the reinforced central regions handle high loads during acceleration and braking, while the less dense end regions reduce stress concentration in sidewall areas during steering maneuvers, thereby maintaining handling precision.
Data Source
Figure 1~1a
Figure 2
Figure 3
AI summary
In a tyre for vehicle wheels a carcass ply (3a, 3b) is obtained by depositing on a radially outer surface (15) with respect to a forming drum (13) a plurality of strip-like elements (14) in circumferential side by side relationship with each other, superimposing a lateral longitudinal portion (18) of a strip-like element (14) on the lateral longitudinal portion (18) of an adjacent strip-like element (14). A central part (17) of each of the strip-like elements (14) comprises a plurality of parallel first cords (15a) having a first average diameter (d1). The two lateral longitudinal portions (18) each having a reduced thickness (S2), with respect to a thickness (S1) of the central part (17), and having at least one second end cord (15b) with a second average diameter (d2) smaller than the first average diameter (d1).