JPH01239790A - Inductive heating device of electromagnetic cooker - Google Patents

Abstract

PURPOSE:To efficiently cool a heating coil for extending its life by placing the heating coil together with an iron core on a mounting plate having a good thermal conductive rate and provided with radiating fins on the undersurface while being molded with humidity-proof silicone rubber resin or the like having the good thermal conductive rate. CONSTITUTION:A spirally wound inductive heating coil 1 is placed on an iron core 2 made of a ferrite core or the like having large permeability through an electric insulating liner 3 and the iron core 2 is placed on a mounting plate 5 made of aluminium or the like having a large thermal conductive rate wherein a large number of radiating fins 4 are integrally formed on its undersurface. The coil 1, the iron core 2 and the mounting plate 5 are integrally molded with a potting material 6 of silicone rubber or the like of good electrical insulation and humidity-proofness, having a large thermal conductive rate. The heat generated in the coil 1 and the iron core 2 is uniformly radiated from the surfaces of the potting material 6 and the radiating fins 4 through the potting material 6 and the mounting plate 5 having the large thermal conductive rate for being effectively cooled and the humidity-proofness increases with the potting material 6 so that the life of the coil 1 can be extended.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for uniformly and efficiently cooling an induction heating coil to extend the life of the coil in a commercial electromagnetic cooker that heats by electromagnetic induction.・)Relating to an induction heating device.

[Conventional technology]

In general, commercial electromagnetic cookers generate eddy currents in the metal to be heated, such as steak bread, by electromagnetic induction due to alternating magnetic flux, and heat the metal using Joule heat caused by this eddy current and the specific resistance of the metal. Ta. A high frequency is used for the alternating magnetic flux in order to increase the current density of the eddy current due to the skin effect and increase the power absorbed by the metal. Creating alternating magnetic flux 8
A! Because heating coils carry a large current and generate a large amount of heat, bare wires were used to increase heat dissipation efficiency, and a fan was used to blow cooling air to cool the coils.

[Problem to be solved by the invention]

This structure has the disadvantage that it is difficult to uniformly blow cooling air over the entire coil, which may cause the coil to locally overheat and shorten its lifespan.

In order to eliminate the above-mentioned drawbacks, the present invention aims to provide an induction heating device for an electromagnetic cooker that can uniformly and efficiently cool an induction heating coil to extend the life of the coil. .

[Means to solve the problem]

In order to achieve the above object, the present invention places a spirally wound coil 1 on an iron core 2 having a large iM TIfI ratio via an insulating liner 3, and provides heat dissipation fins 4 on the underside of the iron core 2. The mounting made of a material with a high heat transfer coefficient is placed on the plate 5, and the coil 1 and the iron core 2 are mounted on the plate 5 using a silicone rubber resin with a high heat transfer coefficient and moisture resistance. It is designed to be integrally molded with a potting material 6 such as.

[Effect]

The heat generated by the coil 1 and the heat generated by the iron core 2 due to the electromagnetic induction action of the coil 1 are transferred from the surfaces of the botting material 6 and the radiation fins 4 via the botting material 6 having a high heat transfer coefficient and the mounting plate 5. Heat is dissipated uniformly and cooled efficiently, and the botting material 6 increases moisture resistance, so the life of the coil 1 can be extended. The iron core 2 is used to appropriately adjust the impedance of the coil 1 and to reduce noise caused by leakage magnetic flux.

〔Example〕

1 to 4 show embodiments of this invention,
As shown in FIG. 5, a spirally wound induction heating coil 1 is placed on an iron core 2 such as a ferrite core with high magnetic permeability via an electrically insulating liner 3, and the iron core 2 has heat radiation fins 4 on the bottom surface. A large number of integrally formed mounts made of aluminum or the like having a high heat transfer coefficient are placed on the plate 5. The coil 1 is wound with a gap of about 11 between adjacent strands, as shown in an enlarged view in FIG. The iron core 2 is formed by dividing a disk into a large number of fan-shaped bodies, each of which is provided with a plurality of through holes 2a in order to increase the heat dissipation effect. By changing the number of fan-shaped bodies in this iron core 2, the impedance of the coil 1 can be adjusted to 8! This is for adjusting N, and fine adjustment can also be made by changing the thickness of the recessed color edge liner 3. Further, since the iron core 2 allows the magnetic flux generated by the coil 1 to pass through with almost no leakage, generation of high frequency noise due to leakage magnetic flux can be reduced and malfunction of the power supply control circuit can be prevented. The power supply control circuit is the fourth
As shown in the figure, the frequency of the current flowing through coil 1 is HFC
T is detected, and high-frequency control is performed using transistor elements TrllT and z that alternately turn on and off in synchronization with this frequency. In other words, the current frequency is determined by the resonant capacitor C and the reactance L of the coil 1, and when the transistor element Tr I turns on, the current flows as shown by the solid line arrow, and when the transistor element Tr□ turns on, the current 12 flows as shown by the dotted line arrow. As shown in the figure, the metal 7, such as steak bread, is heated by the high-frequency electromagnetic induction action of the coil 1. The coil 1, the iron core 2, and the retaining plate 5 are integrally molded with a potting material 6, such as silicone rubber resin, which has high heat transfer coefficient, insulation properties, and moisture resistance.

According to the embodiment, the heat generated by the coil 1 and the heat generated by the iron core 2 due to the electromagnetic induction action of the coil 1 are radiated to the botting material 6 through the botting material 6 having a high heat transfer coefficient and the mounting plate 5. Heat is radiated uniformly from the surface of the fins 4 for efficient cooling, and the potting material 6 increases resistance to 7V, so the life of the coil 1 can be extended. The molding using the botting material 6 is also useful when making the coil 1 alone, and the radiation fins 4 may be omitted if there is sufficient temperature.

〔Effect of the invention〕

According to this invention, in the induction heating device for an electromagnetic cooker,
The heating coil is mounted on a board with a heat radiation fin on the bottom surface, which has a high heat transfer coefficient, and is molded with moisture-resistant silicone rubber resin, etc., which has a high heat transfer coefficient. The effect is that the coil can be cooled uniformly and efficiently and the life of the coil can be extended.

[Brief Description of the Drawings] Fig. 1 is a longitudinal sectional view of an embodiment of the present invention, Fig. 2 is a bottom view seen from the P arrow in Fig. 1, and Fig. 3 is an enlarged longitudinal sectional view of the main part of Fig. 1. Figure 4 is the power supply control circuit diagram of Figures 1 to 3,
FIG. 5 is a plan view of the coils of FIGS. 1, 3, and 4. l...coil, 2...iron core, 3...insulation liner,
4... Heat dissipation fin, 5... Mounting plate, 6... Botting material. Figure 1 Law heat fin Figure 2

Claims (1)

[Claims] 1) In an induction heating device for an electromagnetic cooker in which a spirally wound induction heating coil is placed on an iron core with high magnetic permeability via an insulating liner, the heat transfer coefficient is It is placed on a mounting plate made of a large material, and the coil, iron core, and mounting plate are integrally molded with a potting material such as silicone rubber resin that has insulation properties with high heat transfer coefficient and moisture resistance. Features: Induction heating device for electromagnetic cookers.