Radial Tire Bead Formation via Drum Dilation

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Solution Overview

Problem

Existing tire manufacturing processes are complex and costly due to the use of bulky and mechanically intricate devices for managing annular anchoring structures, which complicate the formation and locking of beads during toroidal conformation, leading to high production and maintenance expenses.

Innovation Solution

A simplified process and apparatus where the carcass sleeve is radially dilated first, and beads are formed subsequently using a configurable drum without dedicated bead management devices, allowing the beads to be axially locked and formed without pre-locking, facilitating the production of high-quality radial tires with reduced equipment costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If dedicated bead management devices are used for managing annular anchoring structures during toroidal conformation, then bead formation and locking can be controlled, but device complexity and maintenance costs increase

Engineering Contradiction:
Improvebead formation controlVSAvoidapparatus structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention extracts and removes the complex dedicated bead management devices from the apparatus. Instead of using specialized mechanisms for managing annular anchoring structures, the patent employs a simplified drum that performs radially outward movement to simultaneously achieve bead formation and locking through the natural behavior of the carcass plies and bead cores during expansion.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The drum is designed to perform multiple functions: it provides the toroidal conformation of the carcass sleeve, forms the beads, and locks the bead cores in position, all through a single radially outward movement mechanism. This multi-functional approach eliminates the need for separate dedicated devices for each operation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If pre-locking mechanisms are used for locking bead cores before toroidal conformation, then bead stability is improved, but apparatus complexity and production costs increase

Engineering Contradiction:
Improvebead stabilityVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention applies preliminary action by radially dilating the drum before the toroidal conformation step. This pre-expansion creates the necessary conditions for automatic bead formation and locking during the subsequent conformation, eliminating the need for separate pre-locking mechanisms while ensuring bead stability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The bead cores and carcass plies are designed to automatically lock together through their own structural characteristics during the radially outward movement and toroidal conformation. The natural interaction between the turned-up terminal zones of the carcass plies and the bead cores provides self-locking without requiring external locking devices.

Inventive Principle:
Principle #25Self-service

3Reliability

If complex mechanical devices are used for managing annular anchoring structures, then bead locking is secure, but maintenance expenses increase

Engineering Contradiction:
Improvebead locking securityVSAvoidmaintenance cost
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The invention removes complex mechanical bead management devices from the system, replacing them with a simplified drum mechanism. This extraction of unnecessary complexity directly reduces maintenance requirements and expenses while maintaining secure bead locking through the natural structural interaction of tire components.

Inventive Principle:
Principle #2Taking out (Extraction)

4Manufacturing precision

If dedicated devices for managing annular anchoring structures are implemented, then bead formation precision is improved, but equipment costs increase

Engineering Contradiction:
Improvebead formation precisionVSAvoidequipment structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The drum is designed as a universal component that achieves multiple objectives: toroidal conformation of the carcass, formation of beads through radially outward movement, and locking of bead cores. This single multi-functional device replaces multiple specialized devices, maintaining precision while reducing overall equipment complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enables the production of high-quality tires with reduced equipment costs and maintenance, ensuring symmetry and preventing bead damage, while maintaining performance qualities, particularly suitable for radial tires with high curvature for motorcycles.

Implementation Method 1

the building drum (10) is radially expanded until it is brought in the third configuration (figures 2c and 3b) to the larger application diameter ("Φ2"). In this manner, the axially central portion (20) of the carcass sleeve is radially dilated and the carcass sleeve assumes a partially toroidal configuration

Methodology Applied
Scientific EffectRadial dilation:

Data Source

PatentEP2925512B1Process and apparatus for building tyres for vehicle wheels
Publication Date: 2018.08.08 PIRELLI TYRE SPA
  • EP2925512B1 patent drawingFigure 1
  • EP2925512B1 patent drawingFigure 2a
  • EP2925512B1 patent drawingFigure 2b

AI summary

The invention relates to a process for building tyres for vehicle wheels, that comprises: winding at least one semi-finished product (19), in form of a continuous strip cut to size, circumferentially around a building drum (10) for forming a carcass sleeve; conforming the carcass sleeve according to a substantially toroidal configuration; fitting, around each of two axially opposite terminal zones (21) of the carcass sleeve, an annular anchoring structure (4); turning up each of the axially opposite terminal zones (21) around the respective annular anchoring structure (4). The toroidal configuration of the carcass sleeve is at least partly carried out before fitting the annular anchoring structures (4) and it comprises: radially dilating an axially central portion (20) of the carcass sleeve while the two axially opposite terminal zones (21) are free. The invention also relates to an apparatus for building tyres.