Tyre Forming Drum With Discontinuous Surface For Joint Formation
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Solution Overview
Problem
Existing forming drums used in tyre manufacturing processes are not adapted to correctly receive and join integral semi-finished products in the form of continuous strips, leading to difficulties in automation and joint execution due to differences in circumferential extension between the central and lateral portions, making it challenging to produce high-quality tyres with uniform performance and geometric characteristics.
Innovation Solution
A forming drum design with a continuous surface of limited circumferential extension is used to allow precise joining of semi-finished products, featuring axially moveable lateral half-portions and a central sector with a discontinuous circumferential surface to facilitate the winding and joining of continuous strip semi-finished products, ensuring uniform circumferential extension and precise joint formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a continuous radially peripheral surface is provided on the forming drum, then the semi-finished product can be wound around the drum, but differences in circumferential extension between central and lateral portions cause difficulties in joining ends and achieving uniform geometric characteristics
Solution Approach 1:
The forming drum is divided into a central sector and two lateral half-portions. The central sector has a discontinuous circumferential surface while the lateral half-portions have continuous surfaces. This segmentation allows the ends of the semi-finished product to be joined at the continuous surface of the lateral half-portions without the problems caused by a fully continuous surface, achieving uniform geometric characteristics while simplifying the device structure.
2Productivity
If integral semi-finished products in form of continuous strip are used, then productivity is improved, but existing forming drums are not adapted to correctly receive and join them due to circumferential extension differences
Solution Approach 1:
The forming drum is pre-configured with specific continuous and discontinuous surface zones before the semi-finished product is applied. The continuous surface is positioned to receive and facilitate the joining of the ends of the continuous strip semi-finished product, while the discontinuous surface prevents excessive circumferential extension differences. This preliminary configuration enables seamless joining of integral semi-finished products, improving productivity without compromising ease of manufacture.
3Loss of substance
If a central sector with discontinuous circumferential surface is introduced, then material usage and manufacturing costs are reduced, but the drum structure becomes more complex with multiple sectors
Solution Approach 1:
The forming drum is designed with different surface qualities in different zones: the central sector has a discontinuous circumferential surface to reduce material usage and costs, while the lateral half-portions have continuous surfaces to enable proper joining of the semi-finished product ends. This local differentiation of surface quality allows material reduction without compromising the functionality required for high-quality tyre production.
Data Source
AI summary
A process for building tyres provides for building a carcass sleeve around a forming drum having an application diameter and two lateral half-portions axially moveable relative to each other. The carcass sleeve comprises at least one carcass ply coaxially engaged around each of the axially opposite end flaps thereof to an annular anchoring structure defining a fitting diameter smaller than the application diameter. The building of the carcass sleeve comprises: applying and stopping a leading end of a semi-finished product in form of continuous strip cut to size against a continuous surface of the forming drum; winding the semi-finished product in form of continuous strip cut to size circumferentially around the forming drum; joining a trailing end of the semi-finished product to the leading end at said continuous surface. The continuous surface is extended only partly around the forming drum. The semi-finished product, except for the leading end and the trailing end, is laid against a discontinuous circumferential surface of the forming drum adjacent to the continuous surface and belonging to the two lateral half-portions.