Tire Carcass Ply Layout for Smooth Surfaces and Lower Vibration
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Solution Overview
Problem
Existing tire production methods result in appearance defects and vibrations due to overlapping carcass ply end portions and difficulty in varying the angle of inclination with respect to the tire width direction, especially with wide tapes having high rigidity.
Innovation Solution
A tire structure and production method using tape-like members with a width of 1 to 10 mm, where adjacent members in the tire circumferential direction are butted at ends and overlap only at rubber portions, eliminating gaps and reducing cord overlaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wide tapes with high rigidity are used for carcass plies, then productivity is improved and dimensional accuracy is enhanced, but it becomes difficult to follow angular variation caused by crown curvature and appearance defects occur due to overlapping at end portions
Solution Approach 1:
The carcass ply is segmented into multiple narrow tape-like members (1-10 mm width) instead of using a single wide tape. This segmentation allows each narrow member to flexibly follow the angular variation caused by crown curvature while maintaining high productivity through automated sequential attachment. The multiple narrow members collectively form the complete carcass ply structure.
Solution Approach 2:
Different attachment patterns are applied to different regions of the tire: at the equatorial plane, tape-like members are butted against each other to prevent overlapping, while at the end portions, they overlap only at rubber portions. This local differentiation resolves the contradiction between maintaining smooth surface appearance and accommodating angular variation.
2Shape
If tapes are attached to not overlap at the tire equatorial plane, then surface smoothness is improved, but it causes appearance defects and vibrations due to overlapping at the end portions of the carcass ply
Solution Approach 1:
The attachment pattern is locally optimized for different regions: at the equatorial plane, tapes are butted to maintain surface smoothness, while at the end portions, they overlap only at rubber portions to eliminate harmful cord overlaps that cause appearance defects and vibrations. This local differentiation resolves the contradiction.
Solution Approach 2:
The inevitable overlapping at end portions due to tire geometry is converted from a harmful factor into a beneficial arrangement by ensuring it occurs only at rubber portions rather than at cord portions. This transforms the potential source of appearance defects and vibrations into an acceptable structural feature.
3Manufacturing precision
If relatively wide tapes with high rigidity are used, then dimensional accuracy is improved, but it is difficult to vary the angle of the carcass ply in the tire width direction
Solution Approach 1:
The carcass ply is divided into multiple narrow tape-like members (1-10 mm width) instead of using wide tapes. This segmentation provides flexibility to vary the angle of each member in the tire width direction to follow crown curvature, while collectively maintaining high dimensional accuracy of the overall tire structure.
Solution Approach 2:
The attachment angle of the tape-like members is made dynamic rather than fixed, allowing variation in the tire width direction to accommodate crown curvature. This dynamic angle adjustment capability is achieved more easily with narrow members compared to wide rigid tapes.
Data Source
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Figure 2
Figure 3~4B
AI summary
The provide is an tire and an tire production method for the tire, wherein the carcass ply is comprised of tape-like members arranged in the tire circumferential direction, in which a plurality of carcass cords arranged parallel to each other are coated with rubber; the tape-like member has a tape width of 1 to 10 mm; on the tire equatorial plane, two of the tape-like members adjacent to each other in the tire circumferential direction are butted against each other at tire circumferential ends thereof; and at the end portions of the carcass ply, two of the tape-like members adjacent to each other in the tire circumferential direction overlap each other only at rubber portions thereof.