Vulcanizing Mold Central Part Preheating for Thermal Inertia

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Solution Overview

Problem

Traditional tire vulcanization devices face challenges in achieving the correct temperature during the first firing due to high thermal inertia, leading to faults and requiring adjustments in cooking time and temperature, which affects productivity and costs.

Innovation Solution

A vulcanization device with a central part that has its own heating elements, allowing independent heating and temperature stabilization before the start of the curing cycle, ensuring the mold is at the correct temperature for optimal tire curing without preheating the heat transfer fluid.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the heat transfer fluid is preheated or heating elements are placed inside the cooking chamber, then thermal energy is provided for vulcanization, but the significant thermal inertia of the mold and press components causes the initial cooking cycles to be carried out at incorrect temperatures

Engineering Contradiction:
Improvecuring temperatureVSAvoidcuring quality
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent applies preliminary action by heating the mold components (shells, bead rings, sectors) to the target temperature before introducing the heat transfer fluid into the curing chamber. This preheating ensures that when the fluid is introduced, the mold is already at the correct temperature, eliminating the thermal inertia problem that caused incorrect temperatures in initial cycles. The heating elements are positioned to heat the mold structure directly rather than heating the fluid first.

Inventive Principle:
Principle #10Preliminary action

2Temperature

If a higher target temperature is set for initial cooking cycles to compensate for thermal inertia, then the mold accumulates heat, but this subsequently overcooks the tire

Engineering Contradiction:
Improvemold temperatureVSAvoidcuring parameters
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The patent resolves this contradiction by performing preliminary heating of the mold to the exact target temperature before the curing cycle begins. This eliminates the need to set higher temperatures to compensate for thermal inertia, as the mold is already prepared at the correct temperature. The heating is controlled to reach precisely the desired temperature, preventing both underheating and overheating.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the traditional approach of heating the heat transfer fluid mechanically (via preheating or heating elements in the fluid path) with a more precise system that directly heats the mold components. This substitution allows for better temperature control and eliminates the thermal inertia issue by heating the mold structure itself before the curing process begins.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If corrective mechanisms are implemented to adjust curing parameters according to the number of curing cycles, then good curing is achieved, but productivity decreases and operating costs increase

Engineering Contradiction:
Improvecuring qualityVSAvoidvulcanization throughput
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent eliminates the need for corrective mechanisms by implementing preliminary heating of the mold before each curing cycle. Since the mold is preheated to the correct temperature, consistent curing quality is achieved from the first cycle without requiring parameter adjustments based on cycle number. This maintains productivity while ensuring quality.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system performs self-service by automatically heating the mold to the required temperature before each curing operation. This self-preparation eliminates the need for external corrective mechanisms or manual adjustments, maintaining both quality and productivity without additional complexity.

Inventive Principle:
Principle #25Self-service

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 ensures consistent and efficient tire curing from the first cycle, eliminating the need for parameter correctors and reducing energy losses, thereby improving productivity and labor costs while maintaining optimal temperature and pressure conditions.

Implementation Method 1

the central part includes heating elements which are made so as to be put into operation before the start-up of the heating and ventilation unit for the heat transfer fluid

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

A heating and mixing unit for a pressurized heat transfer fluid charge is known from document EP 0 686 492. This unit comprises a turbine driven by an electric motor and a heating element

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

This unit comprises a turbine driven by an electric motor and a heating element

Methodology Applied
Scientific EffectMechanical energy conversion:

Implementation Method 4

The heat transfer fluid, usually pressurized steam or nitrogen, circulates within the vulcanizing device between a supply source and the curing chamber

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 5

Some of the thermal energy for vulcanization can also be supplied to the tire blank externally, via the mold shells and sectors

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3221136B1Apparatus and method for vulcanizing tyres
Publication Date: 2019.01.02 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)
  • EP3221136B1 patent drawingFigure 1a~1b
  • EP3221136B1 patent drawingFigure 2~3

AI summary

Tyre vulcanizing device (1) comprising - a vulcanizing mould (4) comprising moulding parts which between them define a curing chamber (7) inside which is arranged - a heating and ventilation unit (20) for the heat-transfer fluid and collaborating with a central part (18) providing support and establishing communication between a heat-transfer fluid inlet and said curing chamber (7). According to the invention, said central part (18) comprises heating elements (37, 42, 50) which are produced in such a way as to be set in operation before the heating and ventilation unit (20) for the heat-transfer fluid that cures the tyre is set in operation.