Tire Forming Core Butting Surface Geometry for Radial Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing rigid core tire forming method experiences steps in the radial direction and increased rubber biting due to thermal expansion and pressure between core segments, which deteriorates tire uniformity and quality, and increasing gaps between butting surfaces to mitigate this worsens rubber flow-in issues.
Innovation Solution
A rigid core with first butting surfaces featuring an outwardly inclined surface portion and a parallel surface portion connected via a borderline, where the parallel surface portion is parallel to the center plane, reduces the inclination angle and area ratio to minimize step formation and maintain disassembly performance without increasing gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the amount of gaps between the first butting surfaces and the second butting surfaces is increased to suppress steps during vulcanization molding, then the steps in the radial direction are reduced, but rubber biting of flow-in rubber occurs and tire quality is reduced
Solution Approach 1:
The invention changes the geometric parameters of the butting surfaces by introducing a parallel surface portion with a specific area ratio (0.05 to 0.70) and a borderline configuration. This modifies the pressure distribution during vulcanization, suppressing step formation without requiring increased gaps, thereby preventing rubber biting while maintaining radial uniformity.
Solution Approach 2:
The butting surface is divided into different regions with distinct functions: the outwardly inclined surface portion handles disassembly by facilitating radial inward movement, while the parallel surface portion (with controlled area ratio) manages pressure distribution during vulcanization. This local differentiation allows each region to optimize its function without compromising the other.
2Ease of operation
If the first butting surface is formed as an outwardly inclined surface to improve disassembly performance, then core segments can be removed radially inwardly, but steps form in the radial direction during vulcanization due to thermal expansion pressure
Solution Approach 1:
The butting surface is segmented into functionally distinct regions: the outwardly inclined surface portion (with angle 0.1 to 3.0 degrees) enables easy disassembly by facilitating radial inward movement of core segments, while the parallel surface portion (with controlled area ratio) suppresses step formation during vulcanization. This local functional differentiation resolves the contradiction between disassembly ease and radial uniformity.
Solution Approach 2:
The butting surface is divided into multiple surface portions (outwardly inclined surface portion and parallel surface portion) with different geometric characteristics and functions. This segmentation allows each portion to independently optimize its performance for its specific function without interfering with the other.
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
This configuration effectively reduces radial steps and inhibits rubber biting while maintaining comparable disassembly performance to conventional cores, without the need for increased gaps between butting surfaces.
Implementation Method 1
The temperature of the core main body (a) increases from an ordinary temperature state (about 15 to 50 degrees C.) during forming a green tire to a high temperature state (100 degrees C. or more) during vulcanization molding. By such temperature rise, the core main body (a) causes a thermal expansion, and pressure is generated between the circumferentially adjacent core segments (c1), (c2).
Data Source
AI summary
A core main body comprises first core segments having a small circumferential width and having both circumferential end surfaces as first butting surfaces, and second core segments having a large circumferential width and having both circumferential end surfaces as second butting surfaces, the core main body is formed into an annular shape by butting the circumferentially adjacent first and second butting surfaces against each other. The first butting surface comprises a parallel surface portion being parallel with a center plane in the circumferential width of the first core segment connected to radially outside of an outwardly inclined surface portion inclined so that the circumferential width increases toward the inside in a radial direction.