Pneumatic Tire Bead Core Hexagonal Inclination Rim Slippage
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Solution Overview
Problem
Pneumatic tires experience rim slippage due to insufficient fastening force, which can lead to wear and damage of the bead base portion, and increasing the fastening force can degrade mountability and durability.
Innovation Solution
A pneumatic tire design featuring a bead core shaped like a hexagon with a specific inclination and a bead base portion that projects inward in the tire radial direction, combined with a reinforcing layer and optimized compression ratio of the rubber, to enhance the fastening force while maintaining mountability and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the inner diameter of the bead core or the circumferential length of the bead heel portion is reduced to increase the fastening force, then the fastening force of the bead portion is improved, but the mountability of the pneumatic tire on the rim is degraded
Solution Approach 1:
The patent applies parameter changes by precisely controlling the inclination angle of the bead core bottom (0° to 5°) and the compression ratio of the rubber member (45% to 55%). These parameter optimizations enable the bead portion to achieve sufficient fastening force while maintaining proper mountability, resolving the contradiction between increasing fastening force and preserving ease of mounting.
Solution Approach 2:
The patent utilizes the dynamic compression of the rubber member between the bead core bottom and the rim flange. The rubber member is compressed within a specific ratio range (45%-55%) during mounting and operation, creating a dynamic fastening mechanism that maintains both mountability and sufficient fastening force throughout the tire's service life.
2Reliability
If the fastening force of the bead portion is increased to suppress rim slippage, then rim slippage is reduced, but the contact pressure on the rim may locally excessively increase, damaging the bead portion
Solution Approach 1:
The patent applies parameter changes by optimizing the inclination angle of the bead core bottom (0° to 5°) and the compression ratio of the rubber member (45% to 55%). These controlled parameter changes enable uniform distribution of contact pressure on the rim, achieving sufficient fastening force to suppress rim slippage while preventing localized excessive pressure that could damage the bead portion.
Solution Approach 2:
The patent applies local quality by creating a specific structural configuration where the bead core bottom is inclined at 0° to 5° relative to the tire rotation axis, and the rubber member is compressed within a controlled ratio range. This localized structural optimization ensures that the fastening force is distributed uniformly across the contact area, preventing stress concentration and maintaining bead portion durability while effectively suppressing rim slippage.
3Force
If the inner diameter of the bead core is reduced to increase fastening force, then the fastening force is improved, but eccentric fitting or defective seating may occur, reducing the fastening force
Solution Approach 1:
The patent applies parameter changes by precisely controlling the inclination angle of the bead core bottom (0° to 5°) rather than simply reducing the inner diameter. This angular parameter optimization, combined with controlling the rubber member compression ratio (45% to 55%), ensures proper seating and eccentric-free fitting while achieving the desired fastening force, thereby resolving the contradiction between force enhancement and fitting precision.
Data Source
AI summary
A pneumatic tire is mounted on a 5° rim. A bead core includes a bottom inclined 0°-5° in a direction in which the bottom diverges outward in the radial direction as the bottom extends from an inner side toward an outer side in the width direction. A bead includes a base, a toe, a heel, and a back surface. The heel connects to the back surface by an arc. The base includes a region between a core lower inner end position on an inner circumferential surface of the bead and being identical to a position of a bead core inner end and a core lower outer end position on an inner circumferential surface of the bead and being identical to a position of a bead core outer end in the width direction. The base has a curved line projecting toward the inner side in the radial direction in a cross-section.