Motorcycle Tire Bead Profile Design for Rim Overlap
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Solution Overview
Problem
Existing motorcycle tires face a trade-off between handling stability and ride comfort, with increased rigidity improving stability under large loads but compromising comfort under small loads.
Innovation Solution
A motorcycle tire design featuring a specific profile for the axially outer surfaces of the bead portions, including a radially inner portion extending linearly and a radially outer portion that protrudes outwardly to form an overlap region with the rim flange, enhancing both radial and torsional rigidity while reducing carcass tension for improved comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the rigidity of the bead portions is increased to improve handling stability under large loads, then handling stability is improved, but ride comfort under small loads is deteriorated
Solution Approach 1:
The bead portion profile is designed with different characteristics in different regions: the radially inner portion has a linear extension for stability, while the radially outer portion has a specific curvature and overlap region for comfort. This local differentiation allows each region to contribute differently to the overall performance, achieving both handling stability and ride comfort simultaneously.
Solution Approach 2:
The invention introduces a new dimensional parameter - the axial protrusion of the radially outer portion forming an overlap region with the rim flange. This additional dimensional feature allows independent optimization of bead rigidity and comfort characteristics without compromising the other, resolving the traditional trade-off between handling stability and ride comfort.
2Manufacturing precision
If the axial width between bead portions is adjusted to coincide with rim width for accurate mounting, then mounting accuracy is improved, but stress concentration on the axially outer surface may occur
Solution Approach 1:
The axially outer surface of the bead portion is designed with a curved profile rather than a straight edge. The radially outer portion curves smoothly and protrudes axially to form an overlap region, which distributes stress along a curved path rather than concentrating it at a sharp corner, while still maintaining precise alignment with the rim flange for accurate mounting.
Solution Approach 2:
The radially outer portion is designed to protrude axially in advance before mounting, creating a predetermined overlap region with the rim flange. This preliminary geometric configuration ensures that stress is distributed favorably during the mounting process and under operational loads, preventing stress concentration while maintaining mounting accuracy.
Data Source
AI summary
A motorcycle tire comprises bead portions each having an axially outer surface provided with a profile which comprises a radially inner portion and a radially outer portion. The radially inner portion is located axially outward of a bead core and extending substantially linearly in the tire radial direction. The radially outer portion is smoothly continued from the radially inner portion and extends radially outwardly to a sidewall portion, while inclining toward the axially outside. When an axial width between the bead portions is adjusted to coincide with a rim width between rim flanges, and an axial center of the axial width coincides with an axial center of the rim width, and further the tire rotational axis coincides with the rotational axis of the wheel rim, then at least a part of the radially outer portion of the profile protrudes axially outwardly from a profile of the inner surface of the rim flange.