Monolithic Bead Core for Pneumatic Tire Stress Mitigation
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Solution Overview
Problem
Conventional pneumatic tire bead structures experience stress and deformation due to bending cycles and cyclic circumferential shifts, leading to reduced service life, delamination, and cracking, particularly at the ends of the reinforcing members.
Innovation Solution
The pneumatic tire features a carcass ply extending between bead structures with a monolithic bead core having a semi-rectangular cross-section, circumferentially wound metal wires, and additional reinforcements like chippers and an apex, which provide enhanced structural support and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional bead structures with turned-up portions and radial reinforcing members are used, then the tire can provide basic structural support, but the ends of the reinforcements experience high stress and deformation leading to reduced service life
Solution Approach 1:
The invention applies local quality by providing additional reinforcements (chipper and/or apex) specifically at the ends of the turned-up portions where stress concentration occurs. These localized reinforcements have different properties and orientations compared to the main radial reinforcing members, specifically designed to address the high stress and deformation conditions at the bead structure ends without modifying the entire reinforcement system.
Solution Approach 2:
The invention uses composite materials by combining multiple types of reinforcing members with different orientations and properties. The bead structure incorporates both radial reinforcing members (carcass ply) and additional reinforcements with different orientations (chipper cords at angles, apex cords), creating a composite reinforcement system that distributes stresses more effectively and prevents delamination and cracking.
2Reliability
If additional reinforcements are added to the bead structure, then stress distribution improves, but the device complexity increases
Solution Approach 1:
The invention applies segmentation by dividing the reinforcement system into distinct functional zones: the main radial carcass reinforcement for overall structural support, and additional localized reinforcements (chipper and/or apex) specifically positioned at the high-stress ends of the turned-up portions. This segmentation allows each reinforcement type to be optimized for its specific function while maintaining manufacturing feasibility.
Data Source
Figure 1~2
AI summary
A pneumatic tire (1) is disclosed comprising at least one bead structure (5) comprising a bead core (21). The bead core (21) has in cross-section a planar radially upper or top surface (25), a planar radially lower or bottom surface (26), and two curved side surfaces. The line (27) extending along the planar radially upper or top surface (25) and the line (28) extending along the planar radially lower or bottom surface (26) both extend in parallel to the axis of rotation (28) of the pneumatic tire (1). Also, a pneumatic tire is disclosed comprising at least one bead structure (5) comprising a bead core (21), wherein the bead core (21) is a one-piece or monolithic bead core (21) having a radial height to axial width ratio less than 1.0, alternatively less than 0.9 or less than 0.8.