Tyre carcass sleeve axial extension for shaping drum coupling
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Solution Overview
Problem
Two-stage building processes for tyres are prone to quality issues due to the weak structure of the green carcass sleeve, which deforms during transfer from the first stage drum to the shaping drum, leading to axial contraction and other unpredictable deformations that affect the precision and repeatability of the tyre-building process.
Innovation Solution
Applying a suitable axial extension to the carcass sleeve before engaging the annular anchoring structures with the annular grip elements, ensuring geometric and mechanical conditions are restored to those set during building, thereby improving the precision and reliability of the coupling between the annular shaping elements and anchoring structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a two-stage building process is used to construct tyres, then the tyre building process can be divided into separate carcass preparation and crown assembly stages, but the green carcass sleeve deforms during transfer between drums, leading to axial contraction and reduced manufacturing precision
Solution Approach 1:
The patent applies preliminary action by pre-tensioning the carcass sleeve on the first stage drum before transfer. The carcass is built with predetermined tension and geometric configuration, and the first stage drum maintains this tension during the transfer process to the second stage drum, preventing deformation and axial contraction that would otherwise occur during handling.
2Ease of manufacture
If the carcass sleeve structure is kept simple and flexible for ease of assembly, then the assembly process becomes easier, but the structure becomes weak and prone to unpredictable deformations
Solution Approach 1:
The patent implements preliminary action by pre-tensioning the carcass sleeve on the first stage drum before transfer. This pre-tensioning stabilizes the flexible carcass structure, preventing unpredictable deformations during handling and transfer while maintaining the ease of assembly benefits of a flexible carcass design.
3Manufacturing precision
If axial extension is applied to the carcass sleeve before engagement, then the geometric configuration and coupling precision are improved, but the process complexity increases
Solution Approach 1:
The patent applies preliminary action by performing the axial extension and pre-tensioning of the carcass sleeve on the first stage drum before transfer to the second stage drum. This preliminary preparation ensures that when the carcass is engaged with the shaping elements on the second stage drum, the geometric configuration and coupling precision are already optimized, reducing the need for additional corrective steps.
Data Source
AI summary
A process and an apparatus for building tyres, wherein, in the process, a carcass sleeve including at least one carcass ply and a pair of annular anchoring structures is transferred to a shaping drum including flange elements that are each engageable with one of said annular anchoring structures. The carcass sleeve is shaped according to a toroidal configuration. Before shaping, annular grip elements respectively carried by the flange elements are radially expanded, each inside one of the annular anchoring structures, in order to engage the carcass sleeve. The annular anchoring structures are moved axially apart from each other before engaging the carcass sleeve by the annular grip elements.