Pneumatic Tire Bead and Sidewall Reinforcement for Durability
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Solution Overview
Problem
The existing pneumatic tire designs lack durability during long-distance travel, particularly in terms of resistance to cord breakage and loosening, and rigidity in the sidewall portions.
Innovation Solution
The design incorporates a toroidal carcass ply that is turned up in each bead portion, with inside and outside bead apex rubbers securing the turned up portion, and a sidewall reinforcing cord layer positioned radially outside the carcass, ensuring a specific radial distance between the sidewall reinforcing cord layer and the outside bead apex rubber to prevent separation and enhance rigidity and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the sidewall reinforcing cord layer is positioned close to or overlapping with the outside bead apex rubber, then the structural compactness is improved, but separation between layers occurs leading to lowered durability performance
Solution Approach 1:
The patent introduces an intermediary spatial relationship (radial spacing of 5-20mm) between the sidewall reinforcing cord layer and outside bead apex rubber, preventing direct contact that causes separation while maintaining structural integrity. This intermediary distance acts as a buffer zone that eliminates the harmful effect of layer separation.
Solution Approach 2:
The patent specifies precise parameter ranges for the radial distance between layers (5-20mm, or 5-30% of tire section height). By controlling this dimensional parameter within specific bounds, the patent prevents separation issues while maintaining compactness, resolving the contradiction between closeness and reliability.
2Reliability
If the sidewall reinforcing cord layer is positioned far from the outside bead apex rubber, then separation is prevented, but the rigidity of the sidewall portion decreases
Solution Approach 1:
The patent optimizes the radial distance parameter within a specific range (5-20mm, or 5-30% of tire section height). This controlled parameter ensures sufficient separation to prevent layer detachment while maintaining close enough proximity to preserve sidewall rigidity, balancing both requirements.
Solution Approach 2:
The sidewall reinforcing cord layer itself provides the rigidity function, and by positioning it at the optimal distance, the structure serves itself to maintain both separation (preventing damage) and rigidity (providing strength) without additional components.
3Ease of manufacture
If the turned up portion of the carcass ply is not properly secured, then the manufacturing process is simplified, but cord breakage and loosening occur reducing durability
Solution Approach 1:
The patent combines multiple securing functions into a single integrated structure where the outside bead apex rubber and sidewall reinforcing cord layer work together to secure the turned up portion. This merged structure provides comprehensive protection against cord breakage and loosening while maintaining manufacturing feasibility.
Solution Approach 2:
The turned up portion is pre-secured between the inside bead apex rubber and outside bead apex rubber during manufacturing. This preliminary securing action ensures cord stability before the tire enters service, preventing future breakage and loosening issues.
Data Source
AI summary
A pneumatic tire comprises: a bead portion provided with an inside bead apex rubber disposed between a turned up portion and a main portion of a carcass ply, and an outside bead apex rubber disposed axially outside the turned up portion and having a radially outer edge; and a the sidewall portion provided with a sidewall reinforcing cord layer disposed axially outside the carcass and having a radially inner edge which is spaced apart from the radially outer edge of the outside bead apex rubber by a radial distance of not less than 5% of a tire section height.