Induction Heater with Dual Coils for Gear and Shaft Hardening
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Solution Overview
Problem
Conventional induction heaters are ineffective for hardening integrated gear and shaft components, particularly those with multiple steps, as they struggle to uniformly heat objects with multiple different-diameter portions, leading to stress concentration and inadequate hardened layers.
Innovation Solution
An induction heating system employing a combination of an annular coil surrounding the gear portion and a linear coil facing the shaft, with alternating currents of different frequencies supplied to each coil to prevent interference and ensure uniform hardening across the gear and shaft surfaces, including steps and varying diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single heating coil is used for heating a work with multiple different-diameter portions, then the device complexity is reduced, but the manufacturing precision of the hardened layer becomes inadequate
Solution Approach 1:
The heating system is divided into multiple independent heating coils, each responsible for a specific region of the workpiece. The first heating coil heats the gear portion while the second heating coil heats the shaft portion, allowing each coil to be optimized for its specific heating zone and ensuring uniform hardened layer formation across different diameter portions.
2Device complexity
If the same frequency alternating current is supplied to both heating coils, then the control system is simplified, but vibration caused by interference increases
Solution Approach 1:
The operating frequency parameter is changed for each heating coil to eliminate interference. The first heating coil operates at a first frequency while the second heating coil operates at a second frequency, which prevents electromagnetic interference and vibration while still allowing independent control of each heating zone.
3Ease of manufacture
If a conventional heating coil is used for a work with a big step between gear portion and shaft, then the ease of manufacture is improved, but the reliability of the hardened layer at the stepped portion decreases
Solution Approach 1:
Different heating coils with different configurations are used for different portions of the workpiece. The first heating coil is designed specifically for the gear portion while the second heating coil is designed for the shaft portion, allowing each coil to provide locally optimized heating that ensures reliable hardened layer formation at critical areas such as the stepped portion.
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 system effectively forms continuous hardened layers on both the gear and shaft, enhancing the structural integrity of components like pinions by preventing vibration-induced interference and ensuring uniform heat treatment across diverse diameters.
Implementation Method 1
induction heater for heating by induction a work
Implementation Method 2
supplying a high-frequency current to the heating coils
Data Source
AI summary
An object of the present invention is to provide an induction heater and an induction heating method capable of heating by induction a work in which a gear portion and a shaft are integrated.An induction heater for a gear portion and a stepped shaft is arranged in such a manner that a first heating coil (annular coil) surrounds the gear portion and that a second heating coil (linear coil) faces the stepped shaft in an axial direction. Alternating currents of different frequencies are supplied to the first heating coil 1 and the second heating coil. Further, a part of the second heating coil is arranged so as to come opposite a boundary between the gear portion and the stepped shaft, thereby connecting a hardened pattern of the gear portion by the first heating coil and a hardened pattern of the stepped shaft by the second heating coil.