Single-Shot Inductor Design for Complex Workpiece Heating

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Solution Overview

Problem

Conventional single-turn channel inductors face challenges in achieving uniform heat treatment of complex workpieces with geometrical irregularities due to excessive current density, leading to premature inductor failure and sensitivity to workpiece positioning, which affects heating intensity and hardness depth.

Innovation Solution

A single-shot inductor design featuring a single crossover section connected to longitudinal leg sections and a collar inductor section that surrounds the entire circumference, forming a complete electrical circuit, with profiling and dual cooling circuits to reduce current density and enhance heating uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional single-turn channel inductors are used for complex workpieces, then the inductor can provide heating capability, but excessive current density leads to premature inductor failure

Engineering Contradiction:
Improveinductor lifeVSAvoidcurrent density
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The inductor is divided into multiple turn sections (first turn, second turn, third turn) with different current densities. Each turn can be independently designed and controlled, allowing the first turn to operate at lower current density for reliability while subsequent turns provide additional heating capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different turns of the inductor are assigned different current density characteristics. The first turn is designed with lower current density to ensure reliability and prevent premature failure, while other turns can be optimized for different heating requirements, creating local quality variations throughout the inductor structure.

Inventive Principle:
Principle #3Local quality

2Reliability

If conventional single-turn channel inductors are used, then heating can be provided, but the system is sensitive to workpiece positioning which affects heating intensity and hardness depth

Engineering Contradiction:
Improveheating consistencyVSAvoidpositioning sensitivity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The heating function is segmented across multiple turns, where each turn contributes to the overall heating pattern. This distribution makes the system less sensitive to positioning errors because the cumulative effect of multiple turns provides a more robust and consistent heating profile regardless of slight workpiece position variations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inductor design changes the current density parameter across different turns, with the first turn operating at lower current density. This parameter variation creates a more tolerant heating system that maintains consistent heating intensity and hardness depth even when workpiece positioning varies, reducing the system's sensitivity to positioning precision.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If conventional single-turn channel inductors are used, then the structure is simple, but uniform heat treatment of complex workpieces with geometrical irregularities is difficult to achieve

Engineering Contradiction:
Improveheating uniformityVSAvoidinductor structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The inductor is segmented into multiple turns with potentially different geometrical configurations. This segmentation allows each turn to be optimized for specific regions of the complex workpiece, enabling uniform heat treatment across geometrical irregularities such as fillets, shoulders, and varying diameters while maintaining a relatively simple overall inductor structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different turns of the inductor are designed with local quality variations to match the geometrical features of the workpiece. Each turn can be tailored to provide appropriate heating distribution for specific regions, achieving uniform heat treatment across complex geometries without requiring a completely complex inductor design.

Inventive Principle:
Principle #3Local quality

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 design increases inductor life, reduces heating sensitivity, and maintains consistent heating intensity across complex workpieces, improving the robustness and repeatability of the induction hardening process.

Implementation Method 1

A typical induction hardening process involves heating the workpiece or the region of the workpiece required to be strengthened up to the austenitizing temperature

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

Since induction heating of a workpiece is dependent upon magnetic flux coupling with regions of the workpiece to induce eddy current heating in the workpiece

Methodology Applied
Scientific EffectEddy current heating: Eddy Currents

Implementation Method 3

induce eddy current heating in the workpiece

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3011063B1Inductor for single-shot induction heating of complex workpieces
Publication Date: 2022.06.01 INDUCTOHEAT INC
  • EP3011063B1 patent drawingFigure 1(a)
  • EP3011063B1 patent drawingFigure 1(b)
  • EP3011063B1 patent drawingFigure 1(c)

AI summary

A single shot inductor is provided to induction heat treat a complex workpiece that has an at least partially cylindrical component with its central axis coincident with the central axis of a circular component and connected at one end to the circular component with a diameter larger than the diameter of the at least partially cylindrical component. The single shot inductor has a single crossover inductor section connected to the first ends of two longitudinal leg inductor sections with the second ends of the two longitudinal leg inductor sections connected to a collar inductor section that surrounds the entire circumference of the at least partially cylindrical component when the complex workpiece is loaded in the single shot one turn inductor for an induction heating application. Alternatively the single shot inductor may have two collar inductor sections interconnected between two longitudinal leg inductor sections where one of the leg sections can accept a supply of alternating current.