Tyre Bead Core Positioning via Partial Air Chamber Inflation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional tire manufacturing processes struggle to maintain the desired concentricity between the bead core and the forming support during the turning up of the carcass ply, as the bead core is subject to radial stresses that can cause it to move out of position, leading to inconsistent tire quality.

Innovation Solution

The process involves partial inflation of an air chamber while the bead core is retained by a positioning device, allowing the first part of the turning up to be completed with the bead core in contact, followed by complete inflation to ensure the bead core adheres to the carcass ply, preventing movement during the remaining turning up process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the bead core is released early during the turning up process to allow carcass ply to turn up freely, then the turning up operation becomes simpler and faster, but the bead core moves out of position due to radial stresses, losing concentricity with the forming support

Engineering Contradiction:
Improveturning up operation speedVSAvoidbead core concentricity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The air chamber is partially inflated before the bead core is released, creating preliminary adhesive forces between the bead core and carcass ply. This preliminary action ensures that when the bead core is released, the adhesive force is already sufficient to maintain concentricity during the turning up operation, allowing both early release for productivity and precision maintenance

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the parameter of air pressure in the air chamber from a binary state (inflated/not inflated) to a graduated state (partial inflation to complete inflation). By controlling the degree of inflation, the system can provide just enough adhesive force to maintain bead core position during turning up while allowing the bead core to be released early for efficient production

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the air chamber is fully inflated immediately to ensure bead core adhesion, then concentricity is maintained, but the turning up process takes longer and requires higher forces

Engineering Contradiction:
Improvebead core concentricityVSAvoidinflation force required
Core Design Contradiction:
Manufacturing precisionVSForce

Solution Approach 1:

The air chamber is partially inflated rather than fully inflated immediately. This partial action provides sufficient adhesive force to maintain bead core concentricity during the critical turning up phase, while avoiding the excessive forces and extended time that would result from complete inflation from the start

Inventive Principle:
Principle #16Partial or excessive action

3Manufacturing precision

If the bead core is held in contact position throughout the entire turning up process, then concentricity is perfectly maintained, but the positioning device must withstand high radial stresses and the process becomes more complex

Engineering Contradiction:
Improvebead core concentricityVSAvoidpositioning device structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention replaces the mechanical positioning device with a pneumatic system (air chamber). Instead of relying on mechanical forces from a positioning device to hold the bead core, the system uses pneumatic pressure to create adhesive forces between the bead core and carcass ply, maintaining concentricity without requiring the positioning device to withstand high radial stresses throughout the entire turning up process

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 method ensures the bead core remains in the desired position, maintaining concentricity and improving tire quality by enhancing the anchoring between the bead core and the carcass ply, reducing the risk of movement and ensuring consistent tire performance.

Implementation Method 1

partial inflation of an air chamber while the bead core is retained by a positioning device, allowing the first part of the turning up to be completed with the bead core in contact

Methodology Applied
Scientific EffectAir pressure: Pressure Increase

Implementation Method 2

complete inflation to ensure the bead core adheres to the carcass ply, preventing movement during the remaining turning up process

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2621716B1Process and apparatus for manufacturing a tyre for vehicle wheels
Publication Date: 2015.01.14 PIRELLI TYRE SPA
  • EP2621716B1 patent drawingFigure 1
  • EP2621716B1 patent drawingFigure 2
  • EP2621716B1 patent drawingFigure 3

AI summary

A process for manufacturing a tyre for vehicle wheels comprises: laying at least one carcass ply (2) on a forming support (50) having a rotation axis (X-X); bringing an annular anchoring structure (10) in contact position with an end edge (2a) of the carcass ply (2); holding, through a positioning device (118), the annular anchoring structure (10) in contact position with said end edge (2a) while an air chamber (141) is partially inflated to carry out a first part of turning up said end edge (2a) around the annular anchoring structure (10); moving the positioning device (118) away from the annular anchoring structure (10); completing the inflation of the air chamber (141) to carry out the remaining part of turning up said end edge (2a) around the annular anchoring structure (10), so as to form a turned up end portion of the carcass ply (2) including the annular anchoring structure (10).