Tire Building Drum Segmentation for Sidewall Accuracy

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Solution Overview

Problem

The existing processes for building tires face challenges in accurately depositing elastomeric components due to structural yielding of the carcass sleeve, particularly in lateral areas, and are limited by the need to remove the carcass sleeve from the building drum, which complicates the introduction of a forming drum and affects the proper engagement of tire beads.

Innovation Solution

Inserting a stiff forming drum into the shaped carcass sleeve after it is coupled with the crown structure allows for flexible production, enabling the construction of sidewalls directly on the shaped carcass sleeve, eliminating the need to remove the carcass sleeve from the building drum and simplifying the introduction of the forming drum, thereby improving operational flexibility and product quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the carcass sleeve is removed from the building drum to introduce a forming drum, then the forming drum can be properly engaged, but the process becomes more complex and time-consuming

Engineering Contradiction:
Improveproper engagement of tire beadsVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention divides the forming drum into two independent drums: a building drum for forming the carcass sleeve and a separate forming drum for shaping the final tire. This segmentation allows each drum to perform its specific function independently, eliminating the need to remove the carcass sleeve from the building drum while still enabling proper bead engagement through the second forming drum.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The carcass sleeve is preliminarily formed on the building drum with pre-positioned beads and crown structure before being transferred to the forming drum. This preliminary action prepares the tire components in advance, allowing the forming drum to simply shape the existing structure rather than engage beads during the forming process, thereby simplifying the overall procedure.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the carcass sleeve is removed from the building drum, then the forming drum can be introduced, but the production time increases

Engineering Contradiction:
Improvestructural integrity of sidewallsVSAvoidproduction time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The carcass sleeve, beads, and crown structure are preliminarily formed and positioned on the building drum before transfer to the forming drum. This preliminary preparation ensures structural integrity is established early, allowing the forming drum to focus only on final shaping operations, thereby reducing total production time while maintaining quality.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

By separating the building and forming operations into two independent drums, the process eliminates the time-consuming removal and re-introduction steps. The building drum continuously produces carcass sleeves while the forming drum simultaneously shapes them, enabling parallel processing that increases overall productivity.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If elastomeric components are deposited on the carcass sleeve during building, then sidewalls can be constructed, but structural yielding reduces deposition accuracy

Engineering Contradiction:
Improvesidewall constructionVSAvoiddeposition accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The carcass sleeve is preliminarily formed with beads and crown structure positioned in advance on the building drum. This preliminary structuring provides a stable foundation that prevents structural yielding during subsequent elastomeric component deposition, thereby improving deposition accuracy while maintaining ease of sidewall construction.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3352979B1Process and plant for building tyres
Publication Date: 2021.03.24 PIRELLI TYRE SPA
  • EP3352979B1 patent drawingFigure 1
  • EP3352979B1 patent drawingFigure 2
  • EP3352979B1 patent drawingFigure 3

AI summary

A substantially cylindrical carcass sleeve (21) is formed on a building drum (20), comprising at least one carcass ply (3) having end flaps (3a) engaged with respective annular anchoring structures (5). An annular crown structure (28) comprising at least one belt layer (8a, 8b, 8c) and one tread band (9) is coaxially arranged around the carcass sleeve (21). The carcass sleeve (21) is toroidally shaped and coupled to the crown structure (28). A forming drum (21) is subsequently engaged (38) in the carcass sleeve (21), shaped according to an inner configuration of the carcass sleeve (21). On each of the axially opposite sides of the carcass sleeve (21) supported by the forming drum (38), at least one radially outer portion (12) of a respective sidewall (10) is then formed, extended from an axially outer edge (9a) of the tread band (9) towards one of said annular anchoring structures (5).