Pneumatic Tire Carcass Turn-Up Structure for Lower Weight and Durability
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Solution Overview
Problem
Pneumatic tires face a challenge in achieving weight reduction while maintaining durability, particularly for high-load applications.
Innovation Solution
A pneumatic tire design featuring a carcass ply with turned-up portions, a belt layer, and reinforcing rubber layers, where the turned-up portions are structured to alleviate tension and are supported by the belt and reinforcing layers, maintaining durability while allowing for weight reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the carcass is formed of a single carcass ply with turned-up portions, then weight reduction is achieved, but durability may be compromised
Solution Approach 1:
The single carcass ply is segmented into three functional portions: a body portion extending between bead cores, turned-up portions turned up around the bead cores, and a specific configuration where the turned-up portions are supported by the belt layer and reinforcing rubber layers. This segmentation allows each portion to perform its specific function while maintaining overall structural integrity and durability despite using a single carcass ply.
Solution Approach 2:
The tire employs a composite structure combining the carcass ply with a belt layer and reinforcing rubber layers. The carcass ply provides the basic structural framework, while the belt layer and reinforcing rubber layers provide additional strength and support, particularly at the turned-up portions. This composite material approach enables weight reduction through the single carcass ply while maintaining durability through the supporting layers.
2Strength
If the turned-up portions are extended outward to improve durability, then strength is improved, but weight reduction is compromised
Solution Approach 1:
The belt layer and reinforcing rubber layers act as intermediary support structures for the turned-up portions of the carcass ply. Instead of extending the turned-up portions themselves to improve durability, the invention uses these intermediary layers to provide the necessary strength and support. This allows the turned-up portions to maintain their optimized, non-extended configuration for weight reduction while still achieving durability through the supporting intermediary layers.
3Weight of moving object
If the carcass ply structure is simplified for weight reduction, then manufacturing is simplified, but structural integrity may be compromised
Solution Approach 1:
The carcass ply is configured with different local qualities in different portions: the body portion provides overall structural support, while the turned-up portions are specifically designed to be turned up around the bead cores and are locally reinforced by the belt layer and reinforcing rubber layers. This local quality differentiation maintains structural integrity in critical areas while allowing weight reduction in less critical areas.
Data Source
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AI summary
Provided is a pneumatic tire capable of achieving weight reduction while maintaining durability. A pneumatic tire 1 includes a carcass 6, a belt layer 7, and reinforcing rubber layers 10. Turned-up portions 6b of a carcass ply 6A each include a first portion 11 located between a body portion 6a and the belt layer 7, a second portion 12 adjacent to each reinforcing rubber layer 10 in a tire axial direction, on an outer side in a tire radial direction with respect to a rim flange Rf of a standardized rim R, and a third portion 13 located between the first portion 11 and the second portion 12. A length Lc of the third portion 13 is 0.8 to 1.4 times a sum (La+Lb) of a length La of the first portion 11 and a length Lb of the second portion 12.