AC Heating Device Using Proximity Effect and Ferromagnetic Body

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Solution Overview

Problem

Conventional alternating current heating methods face challenges in controlling current density and heating temperature distribution, leading to increased energy consumption and limited mobility of the workpiece due to conductors and magnetic flux control issues.

Innovation Solution

An alternating current heating method and device that utilizes a first conductor positioned to generate a proximity effect and a ferromagnetic body to control current density and heating temperature distribution by applying alternating current through terminals attached to the workpiece, with optional insulation and flexible connections to ensure uniform current flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conductor is provided around the workpiece to control current density distribution, then heating temperature distribution is improved, but resistance increases and energy consumption increases

Engineering Contradiction:
Improveheating temperature distributionVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent removes the conventional conductor that surrounded the workpiece and replaced it with a ferromagnetic body. This extraction eliminates the harmful resistance and energy consumption while preserving the heating temperature distribution control through magnetic flux management instead of direct electrical contact

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the fundamental parameter from electrical conduction to magnetic flux control. By using a ferromagnetic body to concentrate magnetic flux rather than a conductive material to conduct electricity, the system achieves temperature distribution control without the energy loss associated with electrical resistance

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If a conductor is provided around the workpiece to control current density, then heating temperature distribution is improved, but mobility of the workpiece and conductor is limited due to wiring connections

Engineering Contradiction:
Improveheating temperature distributionVSAvoidmobility
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent extracts and removes the physical conductor and its wiring connections from the system. By replacing the electrical contact method with a magnetic flux concentration method using a ferromagnetic body, the workpiece gains mobility without being constrained by wired connections, while heating temperature distribution remains controllable through magnetic field manipulation

Inventive Principle:
Principle #2Taking out (Extraction)

3Extent of automation

If magnetic flux derivative is used to control magnetic flux, then magnetic flux control is achieved, but current density distribution and heating temperature distribution cannot be accurately controlled

Engineering Contradiction:
Improvemagnetic flux controlVSAvoidcurrent density distribution
Core Design Contradiction:
Extent of automationVSManufacturing precision

Solution Approach 1:

The patent applies local quality by positioning the ferromagnetic body at specific locations where magnetic flux concentration is needed. The ferromagnetic body creates localized magnetic flux concentration at the workpiece surface, enabling precise control of current density distribution and heating temperature distribution through strategic placement rather than global magnetic flux control

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The ferromagnetic body acts as an intermediary between the power source and the workpiece. It mediates the magnetic flux to concentrate it at specific locations on the workpiece surface, thereby indirectly controlling the current density distribution and heating temperature distribution with higher precision than direct magnetic flux derivative control

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The method and device achieve precise control over current density and heating temperature distribution, enhancing energy efficiency and workpiece mobility by minimizing uneven heating and reducing energy consumption.

Implementation Method 1

providing a first conductor that is electrically floating at a position that generates proximity effect at time of applying the alternating current to the workpiece

Methodology Applied
Scientific EffectProximity effect: Electromagnetic Induction

Implementation Method 2

providing a ferromagnetic body near the workpiece. In this case, the workpiece, the first conductor, and the ferromagnetic body may be provided such that the workpiece is located between the first conductor and the ferromagnetic body

Methodology Applied
Scientific EffectMagnetic flux concentration: Ferromagnetism

Implementation Method 3

heating at least part of the workpiece by applying the alternating current to the workpiece through the first terminal and the second terminal

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4646025A1Ac-energization heating method and ac-energization heating device
Publication Date: 2025.11.05 NHK SPRING CO LTD
  • EP4646025A1 patent drawingFigure 1~2
  • EP4646025A1 patent drawingFigure 3~4
  • EP4646025A1 patent drawingFigure 5~6

AI summary

According to one embodiment, an alternating current heating method includes preparing a conductive workpiece, attaching a first terminal and a second terminal connected to a power source, which is capable of supplying alternating current, to the workpiece, providing a first conductor that is electrically floating at a position that generates proximity effect at time of applying the alternating current to the workpiece, and heating at least part of the workpiece by applying the alternating current to the workpiece through the first terminal and the second terminal.