Tire Bead Elliptical Profile Rim Slip Reduction
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Solution Overview
Problem
Existing tire designs face issues with rim slip and tire uniformity due to inadequate bead area geometry, leading to tire vibration and the need for frequent adjustments.
Innovation Solution
The development of a bead area geometry with an elliptical bead heel profile and specific inclination angles for the bead base portions, combined with a centered bead core and toeuard layer configuration, to enhance the tire's rim fitment and reduce vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bead area geometry is used, then the tire can be manufactured with standard designs, but rim slip and tire vibration occur leading to poor tire uniformity
Solution Approach 1:
The bead heel is designed with an elliptical profile instead of conventional flat or curved geometries. This elliptical curvature creates optimal contact geometry with the rim flange, distributing forces more evenly and eliminating rim slip while improving tire uniformity and reducing vibration.
Solution Approach 2:
The bead base angles are specifically optimized with the axially inner portion inclined at least 5.25° greater than the axially outer portion. This parameter optimization of the bead base geometry improves the compression fit and rubber compression characteristics, eliminating rim slip and enhancing tire uniformity.
2Productivity
If standard bead base angles are used, then manufacturing is simplified, but tire vibration occurs requiring frequent adjustments
Solution Approach 1:
The bead base angles are specifically optimized with the axially inner portion inclined at least 5.25° greater than the axially outer portion, with preferred configurations of 7° and 13.5° respectively. This parameter optimization improves the compression fit and rubber compression characteristics, eliminating tire vibration and reducing the need for frequent adjustments.
Solution Approach 2:
The elliptical bead heel profile creates smooth rubber compression during mounting and operation. This curved geometry eliminates abrupt stress transitions that cause vibration, improving tire uniformity and reducing the frequency of required adjustments.
3Reliability
If the bead core is not centered, then manufacturing alignment is easier, but tire uniformity deteriorates
Solution Approach 1:
The bead base angles are specifically designed to facilitate proper bead core centering, with the axially inner portion inclined at least 5.25° greater than the axially outer portion. This geometric configuration naturally guides the bead core to its centered position during manufacturing, achieving both ease of manufacture and high tire uniformity.
Data Source
AI summary
A pneumatic tire has a carcass structure extending through a pair of opposing bead portions and an inner liner located inward of the carcass structure, each bead portion comprising a bead core about which is wrapped the carcass structure and a toeguard. Each bead portion has a bead toe, a bead base, and a bead heel, the bead base extending between the bead toe and the bead heel. The bead heel has a profile corresponding to a sector of an ellipse or approximates a sector of an ellipse by having a dual radius structure. The bead base may have a dual taper configuration. The bead core may be substantially centered in the bead portion, as determined by the material thickness at three locations about the bead core.