Tire Mold Bead Core Retraction for Resin Penetration

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Solution Overview

Problem

The challenge in tire manufacturing is that resin material struggles to adequately enter between the cord when forming a tire frame member, leading to increased costs and difficulties in achieving adequate air retention and bead portion strength with traditional rubber-covered strand bead cores.

Innovation Solution

A tire mold design where main jigs initially retain a covered bead core, allowing molten resin to solidify before retracting and exposing the contact area, enabling additional resin to fill the gap, ensuring adequate air retention and increased bead strength by forming the tire frame member without the exposed portion of the bead core.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a cable bead core is used to improve adhesion and vulcanization, then manufacturing cost increases and resin material cannot adequately enter between the cord

Engineering Contradiction:
Improveadhesion and vulcanizationVSAvoidresin material penetration
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention applies preliminary action by first forming a covered bead with resin material coating the cord before injection molding. This pre-coating creates initial adhesion and allows subsequent resin to penetrate between cords more effectively, resolving the contradiction between achieving good adhesion and enabling resin penetration.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the physical state parameter of the resin material by using molten resin during injection molding. The resin is injected in a molten state to ensure adequate flow and penetration between cords, then solidifies to provide structural integrity and adhesion, thus resolving the contradiction between resin penetration and adhesion.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If resin material is poured into the cavity with the covered bead retained by jigs, then the covered bead can be retained without displacement, but the jigs prevent resin from entering the contact area

Engineering Contradiction:
Improvecovered bead retentionVSAvoidresin coverage completeness
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The invention applies dynamics by making the jigs retractable rather than fixed. The jigs are retracted after the initial resin pouring to expose the contact area, allowing subsequent resin to fill the previously blocked regions. This dynamic adjustment resolves the contradiction between bead retention and complete resin coverage.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention uses periodic action by dividing the resin pouring process into multiple stages: first pouring resin while jigs are in place to secure the bead, then retracting jigs and pouring additional resin to complete the coverage. This periodic approach resolves the contradiction between stable retention and complete coverage.

Inventive Principle:
Principle #19Periodic action

3Stability of the object's composition

If the jigs remain in contact with the covered bead during molding, then the bead position is maintained, but the bead portion strength is reduced due to exposed portions

Engineering Contradiction:
Improvebead position stabilityVSAvoidbead portion strength
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The invention applies dynamics by retracting the jigs after initial positioning to allow complete resin coverage. This dynamic movement ensures the bead maintains its position during critical phases while allowing full resin penetration afterward to maximize bead portion strength, resolving the contradiction between position stability and strength.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention uses preliminary action by having the jigs perform their positioning function first, then being retracted to allow the resin to provide the final strength enhancement. This sequential approach resolves the contradiction between initial position stability and final strength by addressing each requirement at the appropriate stage.

Inventive Principle:
Principle #10Preliminary action

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 effectively secures adequate air retention and raises the strength of the bead portion, suppressing displacement during tire molding while facilitating easier recycling and resource utilization.

Implementation Method 1

once the poured in molten resin has solidified to a degree, such that the covered bead can be retained without the jigs

Methodology Applied
Scientific EffectSolidification: Freezing

Implementation Method 2

more molten resin material is then poured into the cavity, covering the exposed portion of the covered bead with the resin material

Methodology Applied
Scientific EffectCasting: Freezing

Data Source

PatentEP3165350B1Tire forming mold
Publication Date: 2019.05.08 BRIDGESTONE CORP
  • EP3165350B1 patent drawingFigure 1A~1B
  • EP3165350B1 patent drawingFigure 2
  • EP3165350B1 patent drawingFigure 3A

AI summary

A tire mold (10) comprises a cavity (S) that molds a tire frame member (20) when molten thermoplastic resin material is poured in and a bead core retaining jig (16, 56) that moves into and retracts from the cavity (S). Preferably, the tire mold (10) comprises an outer mold (12) for forming a tire outside face and an inner mold (14) for forming a tire inside face, wherein the bead core retaining jig includes a main jig (16, 56) for fixing a covered bead (11), the main jig (16, 56) being provided at the inner mold (14), and an auxiliary jig (57) for fixing the covered bead (11), the auxiliary jig (57) being provided at the outer mold (12).