Run-Flat Tire Sidewall Structure for Ice Grip and Durability
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Solution Overview
Problem
Studless tires face challenges in maintaining performance on ice during run-flat conditions due to reduced tire internal pressure.
Innovation Solution
A pneumatic tire design featuring a bead core, bead filler, carcass layer, run-flat reinforcing layer, and second filler, with specific rubber gauge ratios and positions to ensure reduced rigidity and increased ground contact area, enhancing ice performance and durability during run-flat running.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the run-flat reinforcing layer is made thicker to improve run-flat durability, then the run-flat running capability is enhanced, but the ground contact area is reduced and ice performance deteriorates
Solution Approach 1:
The patent applies local quality by making the run-flat reinforcing layer thickness position-dependent. Specifically, the rubber gauge G1 of the run-flat reinforcing layer at the bead portion (150% of rim flange height) is controlled to be 0.5mm or less, while other regions may have different thickness requirements. This localized thinning at the critical bead area maintains ground contact and ice performance while preserving run-flat durability through reinforcement in other areas.
2Stability of the object's composition
If the tire side portion rigidity is increased to prevent deformation during run-flat running, then structural stability is improved, but the ground contact area is reduced and ice performance deteriorates
Solution Approach 1:
The patent implements local quality by creating position-dependent rigidity in the tire side portion. The rubber gauge G1 of the run-flat reinforcing layer at the bead portion is specifically controlled to be 0.5mm or less, making this local region more flexible to maintain ground contact. Meanwhile, other portions of the tire can maintain higher rigidity for structural stability, achieving a balance between deformation resistance and contact area maintenance.
3Reliability
If the run-flat reinforcing layer is positioned to maximize run-flat support, then run-flat capability is improved, but the bead portion becomes more susceptible to damage
Solution Approach 1:
The patent applies local quality by differentiating the run-flat reinforcing layer thickness at the bead portion from other areas. The rubber gauge G1 at the bead portion (150% of rim flange height) is controlled to be 0.5mm or less, protecting the bead from damage. Other regions of the run-flat reinforcing layer can be thicker to provide run-flat support, achieving both bead protection and run-flat capability.
Solution Approach 2:
The patent applies preliminary action by pre-positioning the run-flat reinforcing layer with controlled thickness at the bead portion before run-flat conditions occur. The rubber gauge G1 is designed to be 0.5mm or less at this critical location, preparing the bead portion to resist damage during potential run-flat events while maintaining overall run-flat capability through reinforcement in other areas.
Data Source
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AI summary
A pneumatic tire includes a run-flat reinforcing layer (19) disposed on an inner side in a width direction of a carcass layer (13), and a second filler (20) disposed between a turned back portion of the carcass layer (13) and a rim cushion rubber (17). Additionally, a point (P) on a tire outer circumferential surface is defined, the point (P) is located at a position corresponding to 150% of a rim flange height from a measurement point of a rim diameter of a specified rim, a perpendicular line (L) is defined, and the perpendicular line (L) is drawn from the point (P) to a tire inner circumferential surface. At this time, a rubber gauge (G1) of the run-flat reinforcing layer (19) on the perpendicular line (L), and a rubber gauge (G2) of a region from the turned back portion of the carcass layer (13) to a tire outer surface have the relationship 0 < G1/G2 ≤ 0.65.