Tire Body Ply Shape for Uniform Inflation Growth
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Solution Overview
Problem
Wide-based single tires experience uneven inflation growth due to differences in rigidity between the center and shoulder portions, leading to issues like groove bottom cracking and increased sensitivity to load variations, which conventional designs fail to address without increasing tire mass or adverse effects on rolling resistance.
Innovation Solution
A tire design with a body ply that deviates from the conventional equilibrium curve along the bead, sidewall, and shoulder portions, achieving uniform inflation growth by adjusting the geometry in the meridian plane, reducing load sensitivity, and minimizing the break-in period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional equilibrium curve design is used for the body ply, then the tire structure is simple and manufacturing is easy, but the inflation growth is uneven between center and shoulder portions
Solution Approach 1:
The body ply is designed with different geometric characteristics in different regions: in the crown portion, the body ply follows a conventional equilibrium curve pattern, while in the shoulder portions, the body ply is positioned at a greater radial distance from the tire axis. This local differentiation allows uniform inflation growth without requiring complete redesign of the entire body ply structure.
2Stability of the object's composition
If structural stiffness is added to the belt package to restrain inflation growth, then inflation growth control is improved, but the tire mass increases
Solution Approach 1:
The body ply is pre-positioned at a greater radial distance in the shoulder portions before inflation occurs. This preliminary geometric configuration prevents excessive inflation growth in the shoulders during the inflation process, eliminating the need for additional stiffening materials in the belt package.
3Stability of the object's composition
If rubber portions are added to shape inflation growth, then inflation growth uniformity is improved, but the tire mass increases
Solution Approach 1:
The invention changes the geometric parameters of the body ply position rather than adding material. By adjusting the radial position of the body ply in the shoulder portions to be greater than in conventional designs, the inflation growth is controlled uniformly without increasing tire mass.
4Ease of manufacture
If the body ply follows the conventional equilibrium curve, then manufacturing is straightforward, but groove bottom cracking occurs in the shoulder portions
Solution Approach 1:
The body ply design applies different geometric characteristics to different regions: the crown portion maintains conventional equilibrium curve properties for easy manufacturing, while the shoulder portions are positioned at greater radial distances to prevent groove bottom cracking by reducing flex points and stress concentrations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides uniform inflation growth across the tire, reducing the propensity for cracking and load sensitivity, eliminating the break-in period, and maintaining performance without increasing tire mass or rolling resistance.
Implementation Method 1
the body ply helps constrain inflation pressure and determine the overall shape of the tire upon inflation
Implementation Method 2
the rubber of the tire experiences viscoelastic relaxation due to the stresses created by uneven inflation growth
Data Source
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AI summary
A tire having uniform inflation growth is provided. The tire includes a body ply that is displaced from the conventional equilibrium curve along the bead, sidewall, and shoulder portions of the tire in a manner that provides more uniform inflation growth from bead portion to bead portion. Such construction reduces load sensitivity, reduces or eliminates the tire break-in period, and/or decreases the propensity for cracking - particularly along a groove bottom of the tread in the shoulder.