Induction Coil Layout for Uniform Heating of Ring Workpieces
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Solution Overview
Problem
Existing heat treatment methods for ring-shaped workpieces, such as raceway rings for rolling bearings, face challenges in achieving uniform temperature distribution across the circumferential direction due to non-uniform coil pitches and shape changes in helical coils, leading to inefficient heating and increased effort in adjusting coil pitches for varying workpiece dimensions.
Innovation Solution
A heat treatment apparatus with multiple coil members supported by a frame body, allowing for adjustable and independent coil pitches, forming distinct temperature increasing and soaking zones, and a connecting mechanism for simplified power feeding and cooling circuit integration, ensuring uniform heating without altering the coil shape or pitch in the circumferential direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a helical coil with adjusted coil pitch is used to create temperature increasing and soaking zones, then the heating efficiency is improved and workpieces can be soaked at target temperature, but the coil pitch becomes non-uniform in the circumferential direction causing uneven temperature distribution across the workpiece
Solution Approach 1:
The heating coil is divided into multiple independent coil members (first coil member, second coil member, etc.) arranged in the axial direction. Each coil member can be independently positioned and adjusted, allowing the creation of different coil pitch zones (temperature increasing zone with smaller pitch, soaking zone with larger pitch) while maintaining uniform circumferential pitch within each zone. This segmentation resolves the contradiction by enabling zone-based heating control without compromising circumferential temperature uniformity.
2Adaptability or versatility
If the coil pitch is changed to accommodate different workpiece dimensions, then the heating process can be adapted to various sizes, but considerable effort and time are required to adjust the coil pitch
Solution Approach 1:
The coil members are designed to be movable in the axial direction relative to the frame body, allowing dynamic adjustment of coil pitch. The coil members can be repositioned along the axial direction to change the pitch between them, enabling quick adaptation to different workpiece dimensions without time-consuming manual adjustments. This dynamic positioning capability resolves the contradiction between adaptability and adjustment time.
Solution Approach 2:
The heating device is designed with a universal structure where multiple coil members can serve different functions by adjusting their positions. The same coil members can create different pitch configurations for different workpiece sizes, eliminating the need for dedicated coils for each workpiece dimension. This multi-functionality reduces adjustment time while maintaining versatility.
3Use of energy by moving object
If a helical coil is used for induction heating, then the workpiece can be heated directly with high energy efficiency, but the coil shape may change in undesired manner due to coil pitch changes affecting temperature uniformity
Solution Approach 1:
The single helical coil is segmented into multiple independent coil members that are supported separately on the frame body. Each coil member maintains a stable planar configuration with uniform circumferential pitch, preventing the shape changes and temperature non-uniformities that occur in traditional helical coils when pitch is adjusted. This segmentation preserves both energy efficiency and coil shape stability.
Solution Approach 2:
Different regions of the heating zone have different local qualities achieved by adjusting the axial spacing between coil members. The temperature increasing zone uses smaller axial spacing (effectively smaller pitch) for aggressive heating, while the soaking zone uses larger spacing for gentle heat maintenance. Each local region maintains uniform circumferential quality, resolving the contradiction between energy efficiency and shape stability.
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 inductive heating of workpieces to a target temperature with uniform temperature distribution across the circumferential direction, reducing effort and time in adjusting coil pitches for different workpiece dimensions, and enhancing coil pitch reproducibility.
Implementation Method 1
a heating unit 2, which inductively heats a workpiece W to a target temperature
Implementation Method 2
heating unit 2, which inductively heats a workpiece W to a target temperature
Data Source
AI summary
Provided is a heat treatment apparatus (1), including: a heating unit (2), which is configured to inductively heat a workpiece (W) to a target temperature; and a drive mechanism, which is configured to move a plurality of the coaxially held workpieces (W) relative to the heating unit (2) being in an energized state in an axial direction of the workpiece (W), wherein the heating unit (2) includes: a plurality of coil members (11) respectively including a ring-shaped coil portion (11a) arranged coaxially with the workpiece (W) so as to be capable of surrounding the workpiece (W); and a frame body (21), which is configured to support each of the plurality of coil members (11) so as to be movable in the axial direction of the workpiece while maintaining the coaxial arrangement between the coil portions (11a).