Bead Apex Rubber Forming via Continuous Flow on Rotating Core
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Solution Overview
Problem
The existing methods for forming bead apex rubber on pneumatic tire bead cores face challenges such as low adhesion strength, deformation due to cooling, and weight imbalance caused by gaps or overlapping at the joint portion, leading to adhesion issues and difficulty in forming a stable core joint body.
Innovation Solution
A method and device that form bead apex rubber continuously in a full circle on the outer circumferential surface of the bead core by flowing unvulcanized rubber through a molding process with a molding head, utilizing shutters to control the rubber flow and pressure, forming a tip portion, middle section, and joining step to create a joint-less structure with high adhesion strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the bead apex rubber is cooled down after molding to make it easier to handle, then the handling becomes easier, but the adhesion property deteriorates and deformation occurs
Solution Approach 1:
The patent changes the temperature parameter by maintaining the bead apex rubber at high temperature during the entire forming process on the bead core, rather than cooling it down. This parameter change prevents adhesion deterioration and deformation while still enabling easy handling through the high-temperature state that maintains material softness and deformability.
Solution Approach 2:
The patent performs preliminary heating of the bead apex rubber before forming, and maintains this high-temperature state throughout the forming process. This preliminary action ensures the rubber remains soft and deformable during handling and forming, eliminating the need for subsequent cooling while preserving adhesion properties.
2Ease of manufacture
If the bead apex rubber is formed by wrapping and jointing tip and back-end portions, then the forming process is established, but weight unbalance occurs due to gaps or overlapping at the joint portion
Solution Approach 1:
The patent implements continuous forming of the bead apex rubber in a circular motion around the bead core without interruption. The rubber is extruded continuously and formed into a complete circle, eliminating the need for separate tip and back-end portions that would require jointing. This continuous action ensures uniform weight distribution and eliminates gaps or overlapping.
Solution Approach 2:
The patent segments the forming process into three distinct steps (tip portion forming, middle section forming, and joining step) that occur sequentially in a continuous circular motion. This segmentation allows precise control of each phase while maintaining overall continuity, ensuring the tip and back-end portions meet perfectly without gaps or overlapping.
3Strength
If the bead apex rubber is formed with large cross-sectional height to improve durability, then the durability improves, but the rubber falls away due to curling deformation
Solution Approach 1:
The patent changes the temperature parameter to maintain high-temperature state during forming, which prevents the rubber from cooling and curling. This allows the rubber to be formed with large cross-sectional height for improved durability while maintaining shape stability through the sustained high-temperature condition that prevents deformation.
Solution Approach 2:
The patent performs preliminary forming of the bead apex rubber with the desired large cross-sectional shape while the rubber is still hot and deformable. This preliminary action establishes the correct geometry before any cooling-induced curling can occur, ensuring both the durability-providing height and shape stability.
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 approach enhances adhesion strength between the bead apex rubber and the bead core, prevents deformation, and eliminates weight imbalances by forming a joint-less structure, reducing the need for cooling and pasting processes, thereby improving production efficiency and reducing manufacturing complexity.
Implementation Method 1
flowing unvulcanized rubber from a rubber inflow port positioned in a first inner wall surface of a molding head into a bead apex molding chamber
Implementation Method 2
form the bead apex rubber integrally on the outer circumferential surface of the bead core rotating around the core axis
Data Source
AI summary
The present invention forms bead apex rubber with good precision on the outer circumferential surface of the bead core. A molding process, in which unvulcanized rubber is made to flow into a bead apex molding chamber that is surrounded by surfaces that include the outer circumferential surface of a circular bead core and the bead apex rubber is formed directly on the outer circumferential surface of the bead core that is rotating around the core axis, is provided. The molding process comprises: a tip forming step that forms the leading end of the bead apex rubber; a middle section forming step that sequentially forms the bead apex rubber to be continuous with the leading end; and a joining step to join the back end and the leading end of the bead apex rubber by inflowing the unvulcanized rubber therebetween.