Pneumatic Tire Cord Layer Segmentation for Rolling Resistance and Noise
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Solution Overview
Problem
Existing pneumatic tires face a challenge in reducing rolling resistance while maintaining or improving braking and driving performances, as weight reduction to decrease rolling resistance often leads to increased noise emission due to vibration of the tread portion.
Innovation Solution
A pneumatic tire design featuring a carcass with an inclined belt layer and two circumferential cord layers, where the inclined belt layer has cords inclined at 30° or more, and the circumferential cord layers are arranged to enhance rigidity and reduce noise emission by modifying the cord material and arrangement to balance rolling resistance and noise performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the weight of the tire is reduced to decrease rolling resistance, then rolling resistance is improved, but vibration damping property is reduced and noise emission increases
Solution Approach 1:
The belt layer is segmented into multiple cord layers (first circumferential cord layer, second circumferential cord layer, and inclined belt layer) with different cord arrangements and orientations. This segmentation allows each layer to contribute differently to vibration damping while maintaining overall lightweight construction, thereby reducing noise emission without sacrificing rolling resistance performance.
Solution Approach 2:
The patent employs composite cord structures combining different materials (steel cords and organic fiber cords) with different Young's moduli arranged in specific configurations. The first circumferential cord layer uses cords with higher Young's modulus while the second uses cords with lower Young's modulus, creating a composite structure that optimizes both vibration damping and weight characteristics.
2Loss of energy
If the weight of the tire is reduced to improve fuel efficiency, then rolling resistance is reduced, but braking and driving performances may be compromised
Solution Approach 1:
Different regions of the tire structure are assigned different cord configurations and material properties. The first circumferential cord layer at the inner side uses high-stiffness cords for structural support, while the second circumferential cord layer at the outer side uses lower-stiffness cords for vibration damping. This local differentiation maintains braking and driving performance while reducing overall weight.
Solution Approach 2:
The patent introduces an inclined belt layer with cords arranged at an inclination angle of 30° or more relative to the circumferential direction, adding a dimensional aspect to the cord arrangement. This inclined configuration works synergistically with the circumferential cord layers to provide both structural integrity for braking/driving performance and vibration damping for reduced noise, all while maintaining lightweight construction.
Data Source
AI summary
A pneumatic tire comprising a carcass 12, at least one inclined belt layer 13, at least one first circumferential cord layer 14 arranged inward in the tire radial direction of the inclined belt layer 13, a tread 16 arranged outward in the tire radial direction of the inclined belt layer 13, and a second circumferential cord layer 15 which is arranged outward in the tire radial direction so as to cover a tire width direction end of the inclined belt layer 13, and where X is defined as X=Y×n×m×d, Y is the Young's modulus (GPa) of the cord, n is the number of cords implanted (cords/50 mm), d is the cord diameter (mm), and m is the number of the first circumferential cord layers 14, X is smaller than X of the first circumferential cord layer 14.