Inductive Heating Workpiece Holder with Insulating Receiving Area

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Solution Overview

Problem

Existing devices for holding workpieces during inductive heating, such as camshafts, suffer from irregular hardness patterns due to eddy currents induced in both the workpiece and the holder, leading to unnecessary energy consumption and uneven heating.

Innovation Solution

A device with a receiving area made of a material with little or no electrical conductivity, featuring metal receiving fingers that hold the workpiece in a non-positive manner, preventing eddy currents in the holder and allowing for uniform heating with reduced energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a metal holder is used to hold the workpiece during inductive heating, then the workpiece can be securely fixed, but eddy currents are induced in the holder causing uneven heating and irregular hardness patterns

Engineering Contradiction:
Improvesecure fixation of workpieceVSAvoiduniformity of hardness pattern
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The harmful property of electrical conductivity is extracted from the holder material. The patent replaces the metal holder with a holder made of electrically insulating material (such as ceramic or plastic), thereby removing the ability to induce eddy currents in the holder while maintaining its mechanical function of securely holding the workpiece during inductive heating.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The electrical conductivity parameter of the holder material is changed from conductive (metal) to insulating (ceramic or plastic). This parameter change prevents eddy current formation in the holder, eliminating the source of uneven heating and ensuring uniform heat distribution across the workpiece surface for consistent hardness patterns.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a metal holder is used during inductive heating, then the workpiece can be held securely, but unnecessary energy is consumed due to eddy currents in the holder

Engineering Contradiction:
Improvesecure fixation of workpieceVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The harmful property of electrical conductivity is extracted from the holder material. The patent replaces the metal holder with a holder made of electrically insulating material (such as ceramic or plastic), thereby removing the ability to induce eddy currents in the holder while maintaining its mechanical function of securely holding the workpiece during inductive heating.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the previously harmful electrical conductivity of the metal holder into a beneficial property by selecting insulating materials. This eliminates energy loss through eddy currents in the holder, converting the holder from an energy-wasting component to an energy-efficient one that allows selective heating only of the workpiece.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Manufacturing precision

If a metal holder is used for inductive heating, then the workpiece can be positioned accurately, but the holder itself gets heated due to induced eddy currents

Engineering Contradiction:
Improvepositioning accuracy of workpieceVSAvoidtemperature of holder
Core Design Contradiction:
Manufacturing precisionVSTemperature

Solution Approach 1:

The harmful property of electrical conductivity is extracted from the holder material. The patent replaces the metal holder with a holder made of electrically insulating material (such as ceramic or plastic), thereby removing the ability to induce eddy currents in the holder while maintaining its mechanical function of securely holding the workpiece during inductive heating.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The electrical conductivity parameter of the holder material is changed from conductive (metal) to insulating (ceramic or plastic). This parameter change prevents eddy current formation in the holder, eliminating the source of unwanted heating and ensuring uniform heat distribution across the workpiece surface for consistent hardness patterns.

Inventive Principle:
Principle #35Parameter changes

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

Ensures secure fixation and uniform heating of the workpiece, achieving a regular hardness pattern while minimizing energy expenditure by preventing eddy currents in the holder, allowing for efficient inductive heating of complex-shaped workpieces.

Implementation Method 1

The workpiece is exposed to the influence of an electromagnetic alternating field, as a result of which eddy currents are induced in the workpiece. The workpiece is heated by these eddy currents.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

eddy currents are induced in the workpiece. The workpiece is heated by these eddy currents.

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 3

at least the receiving area is made of a material that has little or no electrical conductivity. This design measure prevents the induction of eddy currents in the device

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Data Source

PatentEP2714948B1Device for retaining a workpiece during inductive heating
Publication Date: 2017.07.12 ITG INDUKTIONSANLAGEN
  • EP2714948B1 patent drawingFigure 1~2
  • EP2714948B1 patent drawingFigure 3~4
  • EP2714948B1 patent drawingFigure 5~6

AI summary

The invention relates to a device for retaining a workpiece (6) during inductive heating, in particular during the case hardening of cams of the camshaft of an internal combustion engine, comprising a main body (1) and an accommodating region (3) connected to the main body (1), the workpiece (6) being retained in/on the accommodating region (3) in a form-fit and/or force-closed manner, wherein said device is characterized in that at least the accommodating region (3) is made of a material that has low or no electrical conductivity.