Arc-Shaped Secondary Coil Cooling for Uniform Traverse Hardening

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Solution Overview

Problem

Conventional traverse hardening devices face challenges in efficiently heating shaft-like bodies with varying diameters and shapes, particularly when small diameter parts are located in intermediate positions, leading to inefficiencies and potential overheating at diameter differences, and require cumbersome secondary coil adjustments.

Innovation Solution

The use of arc-shaped secondary coils with integrated cooling mechanisms, allowing for easy replacement and adjustment to accommodate different shaft diameters, and a traverse hardening device design that facilitates efficient induction heating and cooling during the process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional secondary coil member is used for shaft-like bodies with intermediate small diameter parts, then heating uniformity is improved, but the time required to move and remove the coil member increases

Engineering Contradiction:
Improveheating uniformityVSAvoidcoil member movement time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The secondary coil member is divided into multiple arc-shaped coil segments that can be independently positioned and removed. Each segment can be separately manipulated, allowing faster removal compared to a complete circular secondary coil, while still providing uniform heating when properly arranged around the shaft-like body.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If multiple coil members with different outer diameters are used to accommodate various shaft diameters, then adaptability is improved, but device complexity increases

Engineering Contradiction:
Improveadaptability to various shaft diametersVSAvoidnumber of coil members
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Arc-shaped coil segments serve multiple functions: they can be arranged in different quantities and configurations to accommodate various shaft diameters, and can be selectively positioned to match different heating requirements. This universal design replaces the need for multiple complete secondary coils with different outer diameters.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system transitions from fixed complete secondary coils to dynamic arc-shaped segments that can be flexibly arranged, added, or removed based on the specific shaft diameter and heating requirements, providing adaptability without requiring a separate device for each diameter.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If a tertiary coil is added to handle fine pitch diameter differences, then adaptability to varying shaft shapes is improved, but energy input efficiency decreases and overheating risk increases

Engineering Contradiction:
Improvehandling of fine pitch diameter differencesVSAvoidenergy input efficiency
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

Arc-shaped coil segments can be selectively positioned at specific locations along the shaft-like body, allowing concentrated heating at regions with fine pitch diameter differences. This localized heating approach improves energy efficiency by directing energy only where needed, rather than using additional complete coils that would distribute energy across the entire structure.

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 uniform and efficient heating of shaft-like bodies with varying diameters and shapes, reducing energy inefficiencies and overheating, while maintaining high ease of coil replacement and cooling capabilities.

Implementation Method 1

a high-frequency current is caused to flow in the primary coil member to heat the shaft-like body using induction heating

Methodology Applied
Scientific EffectInduction heating: Electromagnetic Induction

Implementation Method 2

a high-frequency current is caused to flow in the secondary coil member to heat the shaft-like body through electromagnetic induction

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

a cooling water path 5 disposed inside the power supply part 2 and the coil part 3 and for supplying cooling water to the coil part 3

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3975664B1Secondary coil module, traverse hardening apparatus, and traverse hardening method
Publication Date: 2025.11.12 NIPPON STEEL CORPORATION
  • EP3975664B1 patent drawingFigure 1~2A
  • EP3975664B1 patent drawingFigure 2B~2C
  • EP3975664B1 patent drawingFigure 3A~3C

AI summary

This secondary coil module includes an arc-shaped coil and cooling jigs. The arc-shaped coil includes a coolant introduction port and a coolant discharge port. The cooling jigs include a coolant introduction pipe having an opening distal end portion configured to be fittable to the coolant introduction port, a coolant discharge pipe having an opening distal end portion configured to be fittable to the coolant discharge port, a first connection component which detachably connects the opening distal end portion of the coolant introduction pipe to the coolant introduction port, a second connection component which detachably connects the opening distal end portion of the coolant discharge pipe to the coolant discharge port, a coolant supply pipe connected to the coolant introduction pipe to extend outward in a radial direction of the arc-shaped coil, and a coolant recovery pipe connected to the coolant discharge pipe to extend outward in the radial direction of the arc-shaped coil.