Tyre Carcass Ply Layout to Prevent Bead Air Pockets

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Solution Overview

Problem

Existing tire manufacturing methods result in the formation of air channels and unsightly depressions on the outer surface of the tire due to incomplete bonding of tire components during the vulcanization process, leading to reduced tire quality.

Innovation Solution

The second carcass layer is positioned laterally to the bead cores and in contact with the bead cores, ensuring proper bonding by enclosing its end sections between the core packs and the first carcass ply, preventing air pockets and indentations through the folding of the first carcass ply around the second carcass ply during tire construction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the second carcass ply terminates in the bead sections lateral to the bead cores with air channels remaining, then the tire construction process is simpler, but air pockets form causing localized shrinkage and depressions on the tire surface

Engineering Contradiction:
Improvetire construction processVSAvoidtire surface quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The second carcass ply is positioned and extended into the bead areas between the first carcass layer and core profiles before vulcanization, ensuring proper bonding interfaces are established in advance. This preliminary positioning prevents air channel formation during the subsequent vulcanization process, eliminating the need for post-processing corrections.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The second carcass layer acts as an intermediary component that fills the space between the first carcass layer and core profiles in the bead areas. By extending into this intermediate zone and terminating in contact with both components, it ensures complete bonding and prevents air pocket formation that would otherwise occur in this gap region.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the second carcass ply is extended into the bead areas between the first carcass layer and core profiles, then air pockets are prevented and tire quality improves, but the construction process becomes more complex

Engineering Contradiction:
Improvetire surface qualityVSAvoidcarcass construction process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The second carcass ply is merged with both the first carcass layer and the core profiles by extending into the bead areas and making contact with both components. This merging creates a continuous bonded structure that eliminates air pockets and ensures uniform tire surface quality after vulcanization.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The second carcass ply is specifically extended into the bead areas where bonding quality is critical, rather than uniformly throughout the entire tire structure. This localized extension ensures high bonding precision in the critical bead regions while maintaining simplicity in other areas of the tire construction.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4377076B1Vehicle tyre and method for constructing a tyre carcass of a vehicle tyre on a carcass machine
Publication Date: 2026.01.28 CONTINENTAL REIFEN DEUTSCHLAND GMBH
  • EP4377076B1 patent drawingFigure 1~2
  • EP4377076B1 patent drawingFigure 3~4
  • EP4377076B1 patent drawingFigure 5~7

AI summary

The invention relates to a vehicle tyre comprising: a tread (1); a belt (6) which comprises at least two layers (6a, 6b); bead regions (2) having bead cores (3) and core profiles (4); a carcass inlay having a first carcass layer (9, 9') and a second carcass layer (10); wherein the first carcass layer (9, 9') comprises a portion (8a) which extends continuously from bead region (2) to bead region (2) and along the inner layer (8), bend portions (9d, 9'd) which extend axially on the bead cores (3), and additional portions (9b) which extend outside in the bead regions (2); and wherein the second carcass layer (10) comprises a continuous portion (10a) which extends from bead region (2) to bead region (2) while in contact with the first carcass layer (9, 9') and ends in the bead regions (2) externally laterally with respect to the bead cores (3). The second carcass layer (10) extends in the bead regions (2) between the first carcass layer (9, 9') on one side and the bead cores (3) together with the core profiles (4) on the other side, and while in contact with these components.