Run-flat Tire Reinforcement Cord Layer for Buckling Suppression
Solution Overview
Problem
In side reinforcement type run-flat radial tires, a buckling phenomenon occurs when a slip angle is input during run-flat running due to reduced internal pressure, causing the tire side portion to bend inward and potentially leading to rim detachment.
Innovation Solution
The implementation of a run-flat radial tire configuration that includes a reinforcement cord layer laid up at an angle of 60 degrees to 90 degrees to the tire circumferential direction, which increases the bending rigidity of the tire side portions and suppresses buckling, combined with side reinforcement rubber that enhances durability and ride comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If side reinforcement rubber is added to reinforce tire side portions, then run-flat capability is improved, but buckling phenomenon occurs during vehicle turning due to increased stiffness
Solution Approach 1:
The reinforcement structure is segmented into multiple functional layers: side reinforcement rubber for run-flat capability, and a separately positioned reinforcement cord layer (steel or synthetic fiber) extending from the tread end toward the bead. This segmentation allows each layer to perform its specific function without interfering with others, preventing buckling while maintaining run-flat capability.
Solution Approach 2:
The tire employs a composite reinforcement system combining side reinforcement rubber with a reinforcement cord layer made of steel cords or synthetic fiber cords. This composite structure provides both the flexibility needed for run-flat operation and the structural stability to prevent buckling during turning maneuvers.
2Ease of operation
If section height is increased to improve ride comfort, then ride comfort is improved, but buckling phenomenon becomes more likely during run-flat running
Solution Approach 1:
The reinforcement cord layer is positioned in a specific three-dimensional space within the tire structure, extending from the tread end region toward the bead area. This spatial arrangement adds structural support in the radial and circumferential dimensions without compromising the section height, thereby preventing buckling while maintaining ride comfort.
3Reliability
If reinforcement cord layer is added at 60-90 degrees angle, then resistance to buckling is improved, but device complexity increases
Solution Approach 1:
The reinforcement cord layer serves multiple functions simultaneously: it provides structural support to prevent buckling, reinforces the tire sidewall, and works cooperatively with the side reinforcement rubber to maintain run-flat capability. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
Data Source
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AI summary
A run-flat radial tire (10) including a carcass (14) spanning between a pair of bead portions (12), a side reinforcement layer (24) provided to tire side portions (22), an inclined belt layer (16) provided at the tire radial direction outside of the carcass (14) and including cord inclined to a tire circumferential direction, a belt reinforcement layer (18) provided at the tire radial direction outside of the inclined belt layer (16) and including cord extending along the tire circumferential direction, and a reinforcement cord layer (32) provided at a tire radial direction outside of the belt reinforcement layer (18) and including cord inclined to the tire circumferential direction.