Run-Flat Tire Sidewall Structure for Ice Traction Retention
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Solution Overview
Problem
Existing pneumatic tires struggle to maintain performance on ice during run-flat running, as the reduced tire internal pressure affects the tire's ability to maintain ground contact and traction.
Innovation Solution
The pneumatic tire design includes a run-flat reinforcing layer with a specific rubber gauge configuration, combined with a second filler between the turned back portion of the carcass layer and the rim cushion rubber, to reduce the rigidity of the tire side portion and enhance ice performance during run-flat running.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a run-flat reinforcing layer is provided with a larger rubber gauge to increase tire side portion rigidity, then run-flat running capability is improved, but ice performance and ground contact area are deteriorated
Solution Approach 1:
The patent applies local quality by creating a multi-layer structure where the run-flat reinforcing layer and second filler are positioned specifically in the lower portion of the tire side wall (below the equatorial plane), while the upper portion maintains different characteristics. This localized reinforcement provides run-flat capability where needed without compromising ice performance in the upper region that contacts icy surfaces.
Solution Approach 2:
The patent uses composite materials by combining the run-flat reinforcing layer (with high tensile strength cords and specific rubber composition) with the second filler (containing different cord materials and rubber composition) to create a composite structure that balances run-flat durability with ice performance, achieving both functionalities through material composition rather than uniform structure.
2Reliability
If the tire internal pressure is reduced for run-flat running, then the tire can continue running after puncture, but the ground contact area and traction on ice are reduced
Solution Approach 1:
The patent segments the tire side wall reinforcement into two distinct functional zones: the run-flat reinforcing layer positioned in the lower portion for structural support during run-flat running, and the second filler positioned above it for maintaining ground contact area and ice performance. This segmentation allows each layer to optimize its specific function without interfering with the other.
Solution Approach 2:
The patent addresses the ground contact area issue by adding a vertical dimension to the solution - stacking the run-flat reinforcing layer and second filler in different vertical positions within the tire side wall cross-section. This dimensional arrangement allows the lower layer to provide run-flat support while the upper layer maintains external tire dimensions and ground contact characteristics.
Data Source
AI summary
A pneumatic tire includes a run-flat reinforcing layer disposed on an inner side in a width direction of a carcass layer, and a second filler disposed between a turned back portion of the carcass layer and a rim cushion rubber. Additionally, a point on a tire outer circumferential surface is defined, the point 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 is defined, and the perpendicular line is drawn from the point to a tire inner circumferential surface. A rubber gauge (G1) of the run-flat reinforcing layer on the perpendicular line, and a rubber gauge (G2) of a region from the turned back portion of the carcass layer to a tire outer surface have the relationship 0<G1/G2≤0.65.