Run Flat Tire Carcass Ply Segmentation for Pinch Cut Resistance
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Solution Overview
Problem
Conventional run flat tires suffer damage from excessive tensile force when encountering potholes or curbstones, leading to potential carcass damage.
Innovation Solution
The design includes a carcass with a first and second carcass ply, each with a toroidal shape and turned-up portions positioned to reduce tensile force and enhance durability, along with bead apex rubbers and side-reinforcing layers to distribute force effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional run flat tire structure with side-reinforcing rubber layers is used, then run flat capability is achieved, but excessive tensile force acts on the carcass when overrunning curbstones or potholes causing pinch cut damage
Solution Approach 1:
The carcass is divided into multiple plies (first carcass ply and second carcass ply) with different orientations and functions. The first carcass ply has turned-up portions that extend radially outward to resist tensile forces, while the second carcass ply has turned-up portions that extend axially to provide additional reinforcement. This segmentation allows each ply to specialize in resisting specific方向的 forces, thereby protecting the carcass from pinch cut damage while maintaining run flat capability.
Solution Approach 2:
The turned-up portions of the carcass plies are configured to extend in multiple dimensions: the first carcass ply extends radially outward from the bead core, while the second carcass ply extends axially. This multi-dimensional configuration creates a three-dimensional reinforcement structure that effectively distributes and resists tensile forces from various directions, preventing carcass damage during curbstone or pothole overrun while preserving run flat functionality.
2Strength
If turned-up portions of carcass extend radially outward to reduce tensile force, then pinch cut resistance is improved, but device complexity increases due to multiple carcass plies with different configurations
Solution Approach 1:
Both the first and second carcass plies serve multiple functions: they provide structural support for run flat capability, resist tensile forces from curbstone or pothole overrun, and maintain tire shape. By designing each ply to perform multiple functions simultaneously, the invention reduces the need for additional separate components, thereby managing complexity while achieving enhanced pinch cut resistance and run flat performance.
Solution Approach 2:
The carcass uses composite construction with at least two different carcass plies having different cord arrangements and orientations. This composite structure combines the strengths of different ply configurations to achieve superior pinch cut resistance and run flat capability. The composite approach allows optimization of each ply's properties for specific functions while integrating them into a unified carcass structure that manages overall complexity.
Data Source
Figure 1
Figure 2
AI summary
Provided is a run flat tire capable of inhibiting damage by reducing tensile force in a carcass when overrunning a pothole or the like. A run flat tire 1 includes: first bead apex rubbers 8A extending from bead cores 5 outward in a tire radial direction; second bead apex rubbers 8B disposed outward of the first bead apex rubbers 8A in a tire axial direction; and first and second carcass plies 6A and 6B. The first carcass ply 6A includes a body portion 6a and turned-up portions 6b. The second carcass ply 6B includes a body portion 6c and turned-up portions 6d. The turned-up portion 6b extends in the tire radial direction through an outer side, in the tire axial direction, of the second bead apex rubber 8B. The turned-up portion 6d extends in the tire radial direction through between the first and second bead apex rubbers 8A and 8B.