Airless Tire Cord Layer Configuration for Steering Stability
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Solution Overview
Problem
Air-less tires face challenges in achieving lightweight designs while maintaining steering stability, as existing constructions with inclined cord layers struggle to enhance the rigidity of the ground contact surface without increasing weight.
Innovation Solution
The air-less tire design incorporates an annular tread ring with an outer reinforcing cord layer having more plies than the inner layer, featuring cords inclined at specific angles and a shear rubber layer to enhance ground contact surface rigidity and mitigate shear stress, while the inner layer provides sufficient radial support through parallel cords and spokes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the outer reinforcing cord layer and inner reinforcing cord layer are both formed of a pair of cord layers with inclined tire cords, then steering stability is improved through increased ground contact surface rigidity, but weight reduction becomes difficult
Solution Approach 1:
The patent applies different cord layer configurations to different radial positions: the outer reinforcing cord layer uses inclined cords (first and second cord plies) to maximize ground contact rigidity, while the inner reinforcing cord layer uses parallel cords (third cord ply) to provide sufficient support with reduced weight. This local differentiation resolves the contradiction by optimizing each layer for its specific functional requirement.
Solution Approach 2:
The reinforcing cord structure is segmented into distinct layers with different orientations: outer layer with inclined cords for ground contact rigidity, inner layer with parallel cords for radial support. This segmentation allows each layer to be optimized independently, achieving overall steering stability without requiring both layers to be heavy and complex.
2Strength
If the number of plies in the outer reinforcing cord layer is increased to improve ground contact surface rigidity, then steering stability is enhanced, but the complexity of the tread ring structure increases
Solution Approach 1:
The patent concentrates the increased ply count specifically in the outer reinforcing cord layer where ground contact rigidity is most critical, while keeping the inner reinforcing cord layer simpler with parallel cords. This local quality approach enhances steering stability through the outer layer's multiple inclined plies without unnecessarily complicating the entire tread ring structure.
Data Source
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AI summary
An air-less tire has, formed on a tread ring: tread rubber for forming a ground contact surface; an outer reinforcement cord layer provided nearest the tread rubber; an inner reinforcement cord layer provided inside the outer reinforcement cord layer in the radial direction of the tire; and a shear rubber layer provided between the outer reinforcement cord layer and the inner reinforcement cord layer. The outer reinforcement cord layer includes: a first cord layer having first cords arranged tilted relative to the circumferential direction of the tire; and a second cord layer provided outside the first cord layer in the radial direction of the tire and having second cords arranged tilted relative to the circumferential direction of the tire in the direction opposite the direction in which the first cords are tilted. The inner reinforcement cord layer includes a third cord layer having third cords arranged parallel to the circumferential direction or the axial direction of the tire.