Tire Forming Drum Segmentation for Stable Coiling

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Solution Overview

Problem

Existing tire manufacturing processes face challenges in achieving high precision and stability during the deposition of continuous elongated elements on forming drums with surface discontinuities, leading to potential deformation, damage, or breakage due to uncontrolled stress variations and vibrations.

Innovation Solution

The process involves using a radially expandable forming drum with circumferential sectors that define an external abutment surface with solid portions and cavities, and an application member that operates in abutment with previously laid coils to mitigate the effects of surface discontinuities, ensuring stable and precise coiling of the continuous elongated element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a forming drum with surface discontinuities (solid portions and cavities) is used for deposition, then the device complexity is reduced and processing speed can be increased, but uncontrolled stress variations and vibrations occur leading to deformation, damage, or breakage of the continuous elongated element

Engineering Contradiction:
Improveprocessing speedVSAvoidstability during deposition
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The forming drum surface is segmented into solid portions and cavities, allowing the continuous elongated element to be deposited on solid portions while cavities provide space for element storage and reduce stress concentration, thereby maintaining stability at higher processing speeds

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The continuous elongated element itself acts as an intermediary between the discontinuous forming drum surface and the deposition process, bridging over cavities and distributing stresses to prevent damage while maintaining reliable deposition

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If high processing speed is used for deposition, then productivity is improved, but precision of coil deposition deteriorates due to uncontrolled vibrations

Engineering Contradiction:
Improveprocessing speedVSAvoidprecision of coil deposition
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The cavities in the forming drum serve as pre-positioned cushioning zones that absorb vibrations and stress variations before they can affect the deposition process, enabling high-speed operation while maintaining precision

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Force

If thrust actions are applied to the continuous elongated element during application, then deposition force is improved, but the element tends to penetrate into cavities causing vibrations and loss of control

Engineering Contradiction:
Improvedeposition forceVSAvoidcontrol during deposition
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

The forming drum surface has local variations with solid portions providing stable deposition zones and cavities providing cushioning zones, allowing thrust forces to be applied locally on solid portions without causing penetration into cavities and subsequent vibrations

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3233458B3Process and apparatus for building tyres for vehicle wheels
Publication Date: 2022.04.27 PIRELLI TYRE SPA
  • EP3233458B3 patent drawingFigure 1
  • EP3233458B3 patent drawingFigure 2
  • EP3233458B3 patent drawingFigure 3

AI summary

A reinforcement annular structure (7a) of a tyre (2) being processed is formed by means of the actions of: arranging a forming drum (19) externally carrying a deposition surface ("S1"); arranging an application member (46) supported in thrust relation towards the deposition surface ("S1"); longitudinally guiding a continuous elongated element (34) towards a point of application ("P") between the deposition surface ("S1") and a work surface (48) presented by the application member (46); winding the continuous elongated element (34) circumferentially around the deposition surface ("S1") in order to form coils ("C") that are axially side-by-side each other. During winding, the work surface (48) of the application member (46) operates in abutment relation against at least one of the coils ("C") previously formed by the continuous elongated element (34).