Pneumatic Tire Apex Segmentation for Load Handling
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Solution Overview
Problem
Existing tires face challenges in achieving simultaneous improvement of durability, handling stability, and reduction of flat spot generation, especially under heavy loads, due to excessive deformation and heat generation in the apex and sidewalls.
Innovation Solution
A pneumatic tire design with a reduced apex height and strategically positioned fillers and strips, where the ratio of thicknesses and positions of components are optimized to minimize deformation and stress, enhancing the tire's structural integrity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the height of the apex is increased to improve stiffness and durability, then the tire can handle heavy loads better, but deformation and heat generation increase causing reduced durability and potential separation damage
Solution Approach 1:
The apex is divided into multiple layers with different materials: a hard outer layer for stiffness and load bearing, and a soft inner layer that follows carcass ply deformation, reducing heat generation and separation risk
Solution Approach 2:
The apex uses composite rubber materials with different hardness levels - the outer layer has higher hardness for structural support while the inner layer has lower hardness to accommodate deformation without generating excessive heat
2Reliability
If the height of the apex is reduced to reduce deformation and heat generation, then durability improves, but stiffness and load handling capability deteriorate
Solution Approach 1:
The apex is segmented into functional layers where the outer hard layer provides stiffness and the inner soft layer reduces deformation, achieving both durability and strength requirements
Solution Approach 2:
Different regions of the apex have different material properties - the outer surface is hard for load bearing while the inner region is softer to reduce heat generation, optimizing both durability and stiffness locally
3Reliability
If fillers are provided outward of the apexes to improve durability and handling stability, then structural integrity improves, but the complexity of the tire structure increases
Solution Approach 1:
The filler is merged with the apex structure, forming an integrated bead assembly where the filler surrounds and supports the apex, improving durability without requiring separate complex components
Solution Approach 2:
The filler serves multiple functions: it provides structural support, improves handling stability, and protects the apex from damage, reducing the need for additional specialized components
Data Source
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AI summary
A normal rim 48 includes a flange 54. The flange 54 forms an outer circumferential bent surface 60 that is bent with a radius Rr of curvature. A first reference line L1 represents a straight line that extends through a center point Pr of the radius Rr, and that is tilted by an angle of 45°. In a state where the tire is inflated to a normal internal pressure and is under 120% of a normal load, Te represents a thickness from an inner cavity surface to an outer surface of the clinch, Tf1 represents a thickness of a filler, Tc1 represents a thickness of the clinch, Ta1 represents a thickness obtained by the thickness Tf1 and the thickness Tc1 being added, and the thicknesses are measured along the first reference line L1, and a ratio (Ta1/Te) of the thickness Ta1 to the thickness Te is greater than 0.4.