Tire Molding Die With Plate-Spring Release for Complex Treads

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Solution Overview

Problem

Conventional tire molds experience high undercut resistance due to projections on the tread design surface, leading to defects such as permanent deformation and projection failure during mold release, especially in tires with complex tread patterns.

Innovation Solution

The mold is designed with a plate spring member between the holder and design surface dividing mold parts, allowing these parts to rotate and elastically deform, reducing undercut resistance by moving away from the holder when the mold is opened.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If projections such as ribs or blades are provided on the tread design surface to form tread patterns, then the tread pattern with recesses and protrusions can be formed, but high undercut resistance is caused during mold release, leading to permanent deformation and projection failure

Engineering Contradiction:
Improvetread patternVSAvoidmold release
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The tread molding part is divided into a plurality of segments arranged in the circumferential direction, with each segment independently movable in the radial direction. This segmentation allows each segment to be released independently, reducing the overall undercut resistance and preventing permanent deformation of the tread pattern during mold release.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The segments are configured to be movable in the radial direction, transforming the static mold structure into a dynamic one. This mobility enables the segments to be separated from the tire after vulcanization, significantly reducing undercut resistance and preventing projection failure during mold release while maintaining the complex tread pattern.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If the tread molding part is divided into multiple segments to facilitate mold release, then ease of operation is improved, but device complexity increases

Engineering Contradiction:
Improvemold releaseVSAvoidmold structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The tread molding part is divided into multiple segments that can be independently moved in the radial direction. This segmentation simplifies the mold release operation by allowing each segment to be separately removed, while the modular design keeps the overall structure manageable and not excessively complex.

Inventive Principle:
Principle #1Segmentation

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 design reduces undercut resistance, preventing defects and facilitating easier mold release, enabling production of tires with complex tread patterns while reducing production costs and device size.

Implementation Method 1

by elastic deformation of the plate spring member toward a radially inner side, the plurality of the design surface dividing mold parts are moved in a direction away from the holder

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4360844B1Tire molding die and tire production method
Publication Date: 2025.10.22 BRIDGESTONE CORP
  • EP4360844B1 patent drawingFigure 1
  • EP4360844B1 patent drawingFigure 2
  • EP4360844B1 patent drawingFigure 3

AI summary

Provided are a mold for forming a tire (1) including a tread molding part (20) which is configured to be opened and closed by moving a plurality of segments (21) in a radial direction, and a tire production method using the same. In the mold for forming the tire (1), each of the segments (21) includes a holder (22); a plurality of design surface dividing mold parts (23) disposed in a circumferentially arranged manner on a radially inner side of the holder (22); and a plate spring member (25) to which the plurality of the design surface dividing mold parts (23) are fixed and in which both ends of the plate spring member (25) in a circumferential direction are fixed to the holder (22), and when the tread molding part (20) is opened, by elastic deformation of the plate spring member (25), the plurality of the design surface dividing mold parts (23) are moved in a direction away from the holder (22) with the plurality of the design surface dividing mold parts (23) being rotated.