Aircraft Tire Belt Layer Layout for Edge Strain and Weight Reduction
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Solution Overview
Problem
Aircraft pneumatic tires face a challenge in reducing weight while maintaining durability and fatigue resistance, particularly at the width directional end portions of the belt, due to the decrease in the number of stacked belt layers which leads to increased tensile/compressive strain and reduced rigidity.
Innovation Solution
The tire design includes a spirally wound belt layer with a ribbon-shaped first strip material and a zigzag belt layer with organic fibers, where the number of stacked layers is increased in the tire side part regions compared to the central region, and the belt cords are angled to distribute strain effectively, satisfying the relation N95 > N50, to reduce weight and enhance fatigue resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the number of stacked belt layers is reduced to decrease tire weight, then weight is reduced, but rigidity of the belt is lowered and tensile/compressive strain in the belt cord increases
Solution Approach 1:
The patent applies local quality by varying the number of stacked belt layers across different regions of the tire. Specifically, the side part regions have a greater number of stacked belt layers compared to the central region, creating non-uniform local properties that address regional stress differences. This allows weight reduction in the central region while maintaining sufficient strength in the high-strain side regions.
Solution Approach 2:
The patent introduces a new dimensional parameter - the angular orientation of belt cords relative to the tire equatorial plane. By controlling the belt cord angle to be within 2° to 10° in side part regions, the patent adds an orientational dimension to the belt layer structure, enabling effective strain distribution and fatigue resistance without simply increasing layer count uniformly.
2Weight of moving object
If the number of stacked belt layers is reduced to decrease tire weight, then weight is reduced, but fatigue resistance performance of the belt cord is lowered
Solution Approach 1:
The patent implements local quality by concentrating additional belt layers specifically in the side part regions where fatigue occurs most frequently during takeoff and landing. This regional differentiation ensures that fatigue resistance is enhanced where needed most, while avoiding unnecessary weight addition in the central region where strain is lower.
Solution Approach 2:
The patent changes the angular parameter of belt cord orientation in side part regions, specifying that belt cords extend at an angle of 2° to 10° relative to the tire equatorial plane. This parameter change optimizes the mechanical response to cyclic loading during fatigue conditions, improving durability without requiring uniform increases in layer count across the entire tire.
3Weight of moving object
If the number of stacked belt layers is reduced to decrease tire weight, then weight is reduced, but rigidity of the belt is lowered
Solution Approach 1:
The patent applies local quality by creating regional differences in belt layer configuration. The side part regions maintain higher rigidity through increased stack counts, while the central region uses fewer layers. This spatial variation in rigidity matches the actual stress distribution in the tire, providing structural stability where required while enabling weight reduction elsewhere.
Data Source
AI summary
A first belt cord made of organic fibers of a spirally wound belt layer extends at an angle of equal to or less than 5° relative to a tire equatorial plane, a second belt cord made of organic fibers of a zigzag belt layer extends at an inclination of an angle of 2° to 45° relative to the tire equatorial plane, to folding back points where the second belt cord is folded back at each width directional end edge of the zigzag belt layer, and a relation of N95>N50 is satisfied. N50 is the number of stacked belt layers of the spirally wound belt layers, at 50% of half the length of a maximum belt width of belt layers from the tire equatorial plane. N95 is the number of stacked belt layers of the spirally wound belt layers, at 95% of half the length of the maximum belt.