Pneumatic Tire Bead Bonding via Dynamic Drum Expansion
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Solution Overview
Problem
Existing methods for forming pneumatic tires often result in uneven compression-bonding of bead members due to gaps between the forming drum and the band member, leading to variations in tire quality and requiring additional work to correct these gaps.
Innovation Solution
A method and device that synchronizes the diameter-expanding operation of the forming drum with the movement of side portions to form step portions in the band member, allowing the bead members to be precisely compression-bonded to the band member on the side surface of the forming drum, reducing the gap between the step portions and the drum surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the forming drum is expanded in diameter to form step portions in the band member, then the bead member can be installed by being pushed against the step, but a gap may form between the step formed between the bladder and the forming drum and the step formed in the ply, causing variation in bead member position and uneven area expansion
Solution Approach 1:
The forming drum is designed with a dynamic expansion mechanism that allows the diameter to be adjusted during the forming process. By expanding the forming drum diameter, step portions are formed in the band member that enable precise bead member positioning while eliminating gaps between steps, thus maintaining both ease of operation and manufacturing precision
Solution Approach 2:
The invention changes the physical parameter of the forming drum diameter during the forming process. By dynamically adjusting the drum diameter, the system creates optimal step portions in the band member that ensure uniform bead member positioning without gaps, resolving the contradiction between operational ease and positioning precision
2Manufacturing precision
If a stitcher is used to bond together the step formed between the bladder and the forming drum to the ply, then the gap between both steps may be fixed, but additional work is required
Solution Approach 1:
The invention extracts and eliminates the need for the stitcher by redesigning the forming drum expansion mechanism. The optimized expansion process directly forms gap-free step portions in the band member, removing the harmful element (gap) without requiring additional corrective operations, thus maintaining precision while improving productivity
3Ease of manufacture
If the bead member is compression-bonded to the band member on the side surface of the forming drum, then the intermediate green tire can be formed, but variation in the position where the bead member compression-bonds may occur, affecting tire quality
Solution Approach 1:
The dynamic expansion of the forming drum creates uniformly distributed step portions in the band member at the exact locations where bead members need to be compression-bonded. This dynamic adjustment ensures that all bead members are positioned uniformly during compression-bonding, maintaining both ease of manufacture and positioning precision for the intermediate green tire formation
Data Source
AI summary
A tire is formed by disposing a cylindrical band member on a forming drum and outer circumferential sides of side portions disposed on both sides of the forming drum in a drum axial direction; expanding in diameter the forming drum and moving the side portions closer together in the drum axial direction; making step portions formed in the band member conform to side surfaces of the forming drum; moving bead members toward the step portions and compression-bonding the bead members to the band member on the side surfaces of the forming drum; and using a turn-up mechanism to wrap the bead members by turning up both end portions of the band member in the drum axial direction to form an intermediate green tire.