JP4945867B2 - Induction heating device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an induction heating device used in general households, restaurants, factories and the like.
[0002]
[Prior art]
A heating structure of a conventional induction heating apparatus will be described with reference to FIGS. FIG. 5 is a cross-sectional view of a conventional induction heating cooker. 1 is an object to be heated by induction using a high frequency magnetic field generated from the heating coil 2, 2 is a heating coil for induction heating the object to be heated 1, and 3 is a heating coil. Although not particularly shown in the figure, an inverter circuit that supplies a high-frequency current to 2 is connected to the heating coil 2. Reference numeral 4 denotes a plate on which the heated object 1 is placed, and the material thereof is ceramic. 5 is a casing, 6 is a coil base on which the heating coil 2 is placed, 7 is a magnetic body embedded in the coil base 6, and the material is ferrite. The magnetic body 7 is used for the purpose of efficiently supplying a high-frequency magnetic field generated from the heating coil 2 to the article 1 to be heated. Reference numeral 10 denotes a power component that generates a large amount of heat among components constituting the inverter circuit 3, and specifically, an IGBT that is a switching element and a diode bridge. Reference numeral 9 denotes a radiator that radiates heat generated from the power component 10.
[0003]
A cooling device 8 cools the heating coil 2 and the power component 10 by forced air cooling from the side of the heating coil 2 using a sirocco fan or the like. The reason for using the sirocco fan is that it is necessary to ensure sufficient cooling air over the entire surface of the heating coil, and the pressure loss for that is large.
[0004]
The figure which looked at the coil stand 6 from the top is shown in FIG. As shown in FIG. 6, the magnetic body 7 is composed of a plurality of rods, and is arranged radially on the lower surface of the coil base 6.
[0005]
[Problems to be solved by the invention]
However, such a conventional induction heating apparatus has the following problems. That is, as described above, the heating coil is placed on the coil base having the magnetic material disposed on the back surface, and it is difficult to pass the cooling air, and it is also necessary to cool the power components. It is necessary to use a sirocco fan, resulting in an increase in the cost of the product.
[0006]
Against this background, regarding a coil base on which a heating coil is placed in recent years, rod-like magnetic bodies as shown in JP-A-61-71581 are arranged radially from the center of the heating coil, and further inside the coil base made of resin. What is buried is proposed.
[0007]
Even in this configuration, the thickness of the magnetic material is large (in general, about 5 mm in consideration of the saturation magnetic flux density because of the rod-like form), and the sum of the thickness and the resin thickness is the coil. Even if cooling air is blown from the side surface of the heating coil, it is difficult to efficiently cool the lower surface of the heating coil (the upper surface of the heating coil has an object to be heated). There is a plate on which is mounted, and between the heating coil and the plate, at least about 5 mm is necessary for efficient heating in principle of induction heating, and because it is extremely thin, cooling on this surface is also greatly I can't expect it).
[0008]
Further, the heating coil and the inverter circuit are separate members, and when viewed as a heating source (that is, the heating coil and the inverter circuit), the occupied volume is large and it is difficult to reduce the size of the apparatus.
[0009]
The present invention solves the above-described conventional problems, reduces the necessary cooling of the heating coil and power components with a simple configuration, and does not require an expensive cooling mechanism such as a sirocco fan, and provides a small induction heating device as a heating source. It is intended to do.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned conventional problems, the induction heating apparatus of the present invention collects heat generated from the heating coil with a high thermal conductor, and further connects the object to be cooled by connecting to a radiator on which a power component is placed. By concentrating at one place and integrating the inverter circuit and the heating coil, the heating source can be reduced in size.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 is a heating coil, a coil base provided with a magnetic body therein and mounting the heating coil, and an inverter circuit that is molded of the same material as the coil base and supplies a high-frequency current to the heating coil. And a heat pipe mounted on at least one of the components constituting the inverter circuit, and a heat pipe provided between the coil base and the inverter circuit to thermally connect the heating coil and the heat radiator And have. As a result, the heat generated from the heating coil is collected by a high thermal conductor, and the object to be cooled is concentrated in one place by connecting to the radiator on which the power components are placed, so only the radiator is cooled. As a result, it is possible to cool even an inexpensive axial fan or the like, and the inverter circuit and the heating coil are arranged with a high thermal conductive material sandwiched therebetween, so that the heating source can be reduced in size.
[0012]
In addition, the magnetic material can prevent induction heating of the high thermal conductor by the heating coil, and the inverter circuit and the heating coil can be molded with the same member to further reduce the size.
[0013]
【Example】
Hereinafter, reference examples and embodiments of the present invention will be described with reference to FIGS.
[0014]
( Reference example )
FIG. 1 is a cross-sectional view of an induction heating apparatus in a reference example related to an embodiment of the present invention, in which 31 is an object to be heated by induction, and 32 is a spiral shape that generates a high-frequency magnetic field when a high-frequency current flows. It is a heating coil wound around. 33 is an inverter circuit for supplying a high-frequency current to the heating coil 32, 34 is a plate, and the material is ceramic. Reference numeral 35 denotes a casing, and 36 denotes a coil base on which the heating coil 32 is placed, including a magnetic body 37, and the material thereof is PET. The magnetic body 37 has a magnetic permeability of about 1800, and rod-like ferrites are arranged radially. Reference numeral 38 denotes a cooling device configured to cool the radiator 39 intensively. Reference numeral 40 denotes an inverter circuit component, specifically, a switching element 45 and a diode bridge 46.
[0015]
The figure which looked at the heat radiator 39 and the inverter circuit 33 from the top is shown in FIG. The reason why the switching element 45 and the diode bridge 46 are mounted on the radiator is that these two parts are extremely lossy compared to other inverter circuit parts. Specifically, the loss of the switching element 45 is about 50 W, the loss of the diode bridge 46 is about 20 W, and as another inverter circuit component, for example, the loss of the resonance capacitor is about 2 W, and the loss of the choke coil is about 10 W. 41 is a high thermal conductor, and in the case of this reference example , a heat pipe is used. When a heat pipe is provided directly under the heating coil 32, induction heating occurs, so a magnetic body 37 is interposed therebetween.
[0016]
The high thermal conductor 41 is thermally connected from the outer diameter to the inner diameter of the heating coil 32 in order to collect heat generated by the heating coil 32. Further, the high thermal conductor 41 is connected to the radiator 39. FIG. 3 shows a view of the radiator 39 and the like viewed from the cooling device 38 side. In FIG. 3, reference numeral 50 denotes a thermal connection fitting, which thermally connects the high thermal conductor 50 and the radiator 39. The inverter circuit 33 and the coil base 36 are arranged with the high heat conductor 41 interposed therebetween.
[0017]
With the above configuration, the heat generated by the heating coil is guided to the radiator 39 by the high thermal conductor 41, so the cooling device 38 only needs to cool the radiator 39 intensively. Therefore, unlike the conventional example, it is not necessary to pass cooling air through the lower surface of the heating coil 32, and the pressure loss is small. Therefore, efficient cooling can be achieved even if an axial fan is used, resulting in an inexpensive induction heating device. It can be done. Normally, when the coil base 36 is brought close to the inverter circuit 33, the temperature rise of the components on the inverter circuit side becomes high due to the heat generated by the heating coil 32, but in the case of this reference example , the above high heat dissipation structure is adopted. Therefore, the inverter circuit and the heating coil can be integrated.
[0018]
Although the number of heat pipes of the high thermal conductor 41 is 1 in this reference example , it may be increased to 2 or 3 depending on the loss. Further, the cross section thereof is not round but may be square.
[0019]
( Example )
FIG. 4 is a cross-sectional view of the induction heating apparatus in the embodiment of the present invention, and the inverter circuit 33 is molded with the same material as the coil base 36. With the above configuration, the heat source can be further miniaturized.
[0020]
In the present embodiment, the material of the coil base 36 is PET, but it may be a resin ferrite material, for example. In this case, the thermal conductivity of the resin ferrite is 1.5 W / m · K, which is two orders of magnitude higher than that of a resin such as PET, so that a further heat dissipation effect is obtained and the magnetic body 37 is also unnecessary. Further, although the entire inverter circuit 33 is configured to be molded, for example, a component having a high component height such as a capacitor may be configured not to be molded. Further, the cooling device and the heating source of this embodiment may be integrated.
[0021]
【Effect of the invention】
As described above, according to the present invention, the cooling of the heating coil and the inverter circuit component can be realized simply and inexpensively, and the apparatus can be miniaturized.
[Brief description of the drawings]
1 is a cross-sectional view of an induction heating device in a reference example of the present invention. FIG. 2 is a plan view of a radiator and an inverter circuit. FIG. 3 is a cross-sectional view of a radiator and the like viewed from the cooling device side. 4] Cross-sectional view of the induction heating device in the embodiment of the present invention [Fig. 5] Cross-sectional view showing the component structure of the conventional induction heating device [Fig. 6] FIG.
32 Heating coil 33 Inverter circuit 39 Radiator 41 High heat conductor

Claims (1)

A heating coil, a coil base provided with a magnetic body therein and mounting the heating coil, an inverter circuit molded with the same material as the coil base and supplying a high-frequency current to the heating coil, and components constituting the inverter circuit And a heat pipe installed between at least one of the coil base and the inverter circuit, and a heat pipe that thermally connects the heating coil and the heat radiator. Heating device.

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