Tire Mold Segment Extrusion for Lower Release Force

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Solution Overview

Problem

Conventional tire molds require significant driving force to release segments from the tread molding part due to simultaneous peeling of the tread design surface, leading to high initial mold releasing resistance.

Innovation Solution

The mold is designed with extrusion members that protrude from the tread design surface during mold opening, assisted by a cam mechanism, to reduce the force required for segment movement by pressing the tread and allowing gradual separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If segments are moved radially outward to open the tread molding part, then the tire can be released from the mold, but a great driving force is required in the initial stage due to simultaneous peeling of the tread design surface

Engineering Contradiction:

Improvemold releasing operationVSAvoiddriving force for segment movement

Core Design Contradiction:

Ease of operationVSForce

Solution Approach 1:

The tread molding part is divided into multiple segments that can be moved independently. The extrusion member is integrated with each segment, allowing localized action at different positions along the tread design surface, thereby reducing the simultaneous peeling effect and the driving force required.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The extrusion member protrudes from the tread design surface before the segment is fully moved radially outward. This preliminary protrusion creates a pressing action that gradually separates the tread from the mold surface, reducing the peak driving force required for segment movement.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If the tread design surface peels off simultaneously from all segments, then the mold opening is completed quickly, but the friction force is high requiring greater driving force

Engineering Contradiction:

Improvemold opening speedVSAvoidfriction force during segment movement

Core Design Contradiction:

ProductivityVSForce

Solution Approach 1:

The extrusion member protrudes beforehand to create a pressing action that gradually separates the tread from the mold surface. This preliminary separation reduces friction force during the subsequent segment movement, allowing faster mold opening with lower force requirements.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The extrusion member acts as an intermediary element between the segment and the tread design surface. It protrudes to create a controlled separation zone, reducing direct friction between the segment and the tread surface during mold opening.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP4360846B1Tire molding mold and tire manufacturing method

Publication Date: 2025.12.31 BRIDGESTONE CORP

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AI summary

Provided are a mold for forming a tire (1) including an annular 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 segment (21) includes an extrusion member (30) which protrudes from a tread design surface (20c) for forming a tread (2c) of the tire (2) when the tread molding part (20) is opened after vulcanization molding of the tire (1) to press the tread (2c) of the tire (2) after the vulcanization molding.