Pneumatic Tire Reinforcing Rubber Layer Crescent Cross-Section
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Solution Overview
Problem
Conventional run-flat tires compromise ride comfort due to increased thickness of the reinforcing rubber layer for improved durability, leading to decreased ride quality when air pressure is lost.
Innovation Solution
A pneumatic tire design with a crescent-like meridian cross-section reinforcing rubber layer, where the radius of curvature of the carcass layer is smaller than the tire external contour, enhancing vertical stiffness while maintaining run-flat durability without increasing the cross-sectional thickness of the reinforcing rubber layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the reinforcing rubber layer is increased to improve run-flat durability, then run-flat durability performance is improved, but ride comfort deteriorates
Solution Approach 1:
The reinforcing rubber layer is designed with non-uniform thickness distribution, being thicker at the bead portion and thinner at the crown portion. This local variation allows the layer to provide enhanced run-flat durability where needed (at the bead) while reducing negative impacts on ride comfort (at the crown), thus resolving the contradiction between durability and comfort.
Solution Approach 2:
The patent specifies precise thickness parameters for the reinforcing rubber layer: 3-7mm at the bead portion and 1-3mm at the crown portion. By controlling these dimensional parameters within specific ranges, the invention achieves optimal balance between run-flat durability (requiring thicker reinforcement) and ride comfort (requiring thinner reinforcement), thereby resolving the technical contradiction.
2Reliability
If the thickness of the reinforcing rubber layer is increased to suppress sidewall deformation, then run-flat travel capability is improved, but tire weight increases
Solution Approach 1:
The reinforcing rubber layer applies thickness variation strategically: thicker sections (3-7mm) are placed where structural support is critical for run-flat capability (bead portion), while thinner sections (1-3mm) are used where less reinforcement is needed (crown portion). This localized reinforcement achieves run-flat travel capability without uniformly increasing tire weight across the entire structure.
Solution Approach 2:
Instead of uniformly thickening the reinforcing layer across the entire tire, the invention applies reinforcement selectively and partially - concentrating thickness where it provides maximum run-flat benefit (at the bead) while minimizing weight addition elsewhere. This partial action approach achieves the necessary run-flat capability with minimal weight penalty.
Data Source
AI summary
A pneumatic tire includes a reinforcing rubber layer disposed in the sidewall portions, the reinforcing rubber layer having a crescent-like meridian cross-section. When the tire is assembled on a regular rim and in an unloaded state with an internal pressure of 0 kPa, a radius of curvature (RP) is smaller than a radius of curvature (RO), an arc of the radius of curvature (RP) joining an intersection (Pa) of a carcass layer and a straight line (La), an intersection (Pb) of the carcass layer and a straight line (Lb), and an intersection (Pc) of the carcass layer and a straight line (Lc), and an arc of the radius of curvature (RO) joining an intersection (Oa) of the straight line (La) and a tire external contour, an intersection (Ob) of the straight line (Lb) and the tire external contour, and an intersection (Oc) of the straight line (Lc) and the tire external contour.