Pneumatic Tyre Bead Structure for Long-Term Air Leak Resistance
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Solution Overview
Problem
Pneumatic tires face challenges in maintaining air pressure over a long period due to air leak resistance issues, as existing designs do not effectively prevent air leakage between the bead portions and the rim.
Innovation Solution
The pneumatic tire design incorporates an air-impermeable inner liner extending between bead portions with specific dimensions and extensions, a carcass ply with turn-up portions, and protrusions to enhance air leak resistance, while maintaining a bead base diameter less than 99.7% of the rim diameter to increase tightening force and prevent air leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the bead base diameter is increased to improve mountability, then the tyre can be mounted more easily on the rim, but air leakage between the bead portions and rim increases
Solution Approach 1:
The invention optimizes the bead base diameter parameter to be less than 99.7% of the rim diameter, creating a specific clearance that generates sufficient tightening force to prevent air leakage while maintaining ease of mounting. This precise parameter control resolves the contradiction between mountability and air leak resistance.
2Reliability
If the inner liner is extended beyond the bead core to improve air leak resistance, then air leakage is reduced, but the complexity of the tyre structure increases
Solution Approach 1:
The inner liner is divided into distinct functional segments: a main body portion and extension portions that specifically extend into the bead portions. This segmentation allows the liner to provide enhanced air leak resistance at critical locations without requiring complex structures throughout the entire liner, thus resolving the contradiction between reliability and device complexity.
3Reliability
If the bead portion thickness is increased to improve air leak resistance, then air leakage is reduced, but the weight of the tyre increases
Solution Approach 1:
The tyre structure implements local quality enhancement by concentrating increased thickness specifically in the bead portions where air leakage occurs, while maintaining normal thickness in other areas. The bead portion thickness is controlled within 2-5mm, providing localized air leak resistance without significantly increasing overall tyre weight.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design significantly improves air leak resistance, maintains better mountability, and reduces rim slip, as demonstrated by improved air pressure retention and mounting ease in tests, while maintaining effective ground contact and cornering performance.
Implementation Method 1
an inner liner having an air-impermeable property and extending between the pair of bead portions
Implementation Method 2
the pair of bead portions has a bead base diameter being less than 99.7% of a rim diameter of a standard wheel rim on which the pneumatic tyre is to be mounted
Implementation Method 3
increase tightening force and prevent air leakage
Data Source
AI summary
A pneumatic tyre includes a pair of bead portions having respective bead cores therein, each bead core defining a core innermost end in a tyre radial direction, and an inner liner having an air-impermeable property and extending between the pair of bead portions, wherein in each of the pair of bead portions, the inner liner comprises an innermost end in the tyre radial direction located inwardly of the core innermost ends in the tyre radial direction, and the pair of bead portions has a bead base diameter being less than 99.7% of a rim diameter of a standard wheel rim on which the pneumatic tyre is to be mounted.