Traverse Hardening Device with Segmented Secondary Coils

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Solution Overview

Problem

Existing traverse hardening devices face challenges in efficiently heating and cooling shaft-shaped bodies with small-diameter portions in the middle, leading to difficulties in removing secondary coil members from such configurations.

Innovation Solution

A traverse hardening device with multiple secondary coil members disposed radially outside the small-diameter portion, separated in the circumferential direction, and a primary coil member that moves axially to generate induction currents and Joule heat, allowing for efficient heating and easy removal of the secondary coil members.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single secondary coil member is used for small-diameter portions, then the air gap is uniform and heating is efficient, but it takes time to move and remove the coil member from the shaft-shaped body

Engineering Contradiction:
Improveheating efficiencyVSAvoidtime to move and remove coil member
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The secondary coil member is divided into multiple segments (first secondary coil member and second secondary coil member) that can be independently positioned and removed. This segmentation allows each segment to be quickly detached from different small-diameter portions without requiring movement of a single long coil member along the entire shaft length.

Inventive Principle:
Principle #1Segmentation

2Productivity

If the secondary coil member is positioned close to the small-diameter portion, then heating efficiency is improved, but the coil member interferes with the main body portion when the small-diameter portion is in the middle of the shaft

Engineering Contradiction:
Improveheating efficiencyVSAvoidcoil member removal
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

By dividing the secondary coil member into segments, each segment can be positioned close to its corresponding small-diameter portion for efficient heating, while the segmented structure allows easy removal without interference from other portions of the shaft.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each secondary coil segment is specifically positioned to match the local geometry of small-diameter portions, allowing optimal heating at each location while avoiding interference with the main body portion through strategic placement and independent removal capability.

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

Enables efficient heating of both main and small-diameter portions of the shaft-shaped body and facilitates easy removal of secondary coil members, improving the overall traverse hardening process.

Implementation Method 1

a primary coil member which is formed in an annular shape, through which a high frequency current flows, and into which the shaft-shaped body is inserted

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a high frequency current flows through the primary coil member to heat the shaft-shaped body by induction heating

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 3

a plurality of secondary coil members, having an outer diameter smaller than an inner diameter of the primary coil member, which are disposed inside the primary coil member, on a radially outer side of the small-diameter portion of the shaft-shaped body

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 4

heating the small-diameter portion by induction heating

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 5

the shaft-shaped body is more efficiently heated

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3770285B1Traverse hardening device and traverse hardening method
Publication Date: 2024.03.20 NIPPON STEEL CORPORATION
  • EP3770285B1 patent drawingFigure 1
  • EP3770285B1 patent drawingFigure 2
  • EP3770285B1 patent drawingFigure 3

AI summary

The present invention provides a traverse hardening device for performing traverse hardening on a shaft-shaped body including a main body portion and a small-diameter portion which is provided in a middle portion of the main body portion in an axial direction and has an outer diameter smaller than that of the main body portion. The traverse hardening device includes a primary coil member which is formed in an annular shape, through which a high frequency current flows, and into which the shaft-shaped body is inserted, and a plurality of secondary coil members which are located radially outside the small-diameter portion of the shaft-shaped body, are disposed inside the primary coil member, and are disposed to be separated from each other in a circumferential direction. The present invention also provides a traverse hardening method.