Pneumatic Tire Reinforcing Layer Geometry for Retread Yield
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Solution Overview
Problem
Retread tires face challenges in maintaining the yield of base tires due to radial growth and exposure of belt layers during the buffing process, especially in tires with low aspect ratios, leading to belt-edge-separation and reduced durability.
Innovation Solution
A pneumatic tire design featuring a carcass layer, a belt layer with specific angle configurations, and a circumferential reinforcing layer, where the distances from the reinforcing layer to the wear end surface are optimized to increase ground contact pressure and reduce radial growth, thereby suppressing belt layer deformation and exposure during buffing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the tire uses a low aspect ratio design with circumferential reinforcing layer, then the tread portion maintains its shape, but radial growth occurs during buffing causing belt layer exposure
Solution Approach 1:
The patent optimizes the ratio of distance De (from end portion of circumferential reinforcing layer to wear end surface) to distance Dcc (from circumferential reinforcing layer to wear end surface on equatorial plane) to be 1.05 or more. This parameter change ensures that the circumferential reinforcing layer is positioned appropriately to control radial growth during buffing while maintaining tread shape, preventing belt layer exposure and improving base tire yield for retreading
2Stress or pressure
If the circumferential reinforcing layer is positioned closer to the wear end surface, then ground contact pressure increases, but radial growth is reduced suppressing belt layer deformation
Solution Approach 1:
The patent specifies that the ratio De/Dcc should be 1.05 or more, which optimizes the positioning of the circumferential reinforcing layer. This parameter optimization achieves both increased ground contact pressure on shoulder land portions and suppression of radial growth that would cause belt layer deformation and exposure during buffing
Data Source
AI summary
The pneumatic tire includes at least three circumferential main grooves extending in the tire circumferential direction and a plurality of land portions partitioned and formed by the circumferential main grooves. Also, the belt layer is formed by laminating a pair of cross belts having a belt angle, as an absolute value, of not less than 10° and not more than 45° and of mutually opposite signs, and a circumferential reinforcing layer having a belt angle within a range of ±5° with respect to the tire circumferential direction. Also, when viewed as a cross-section from the tire meridian direction, the distance Dcc on the tire equatorial plane from the circumferential reinforcing layer to the wear end surface and the distance De from the end portion of the circumferential reinforcing layer to the wear end surface have a relationship such that 1.06≤De/Dcc.