JP3831985B2 - Induction heating device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an induction heating apparatus.
[0002]
[Prior art]
Hereinafter, a conventional heating coil and induction heating apparatus will be described. In FIG. 3, 1 is a heating coil, 2 is an inverter circuit, 3 is a pan, 4 is a control circuit, 5 is a fan, and 6 is an induction heating device body. A high frequency current is passed through the heating coil 1 by the inverter circuit 2. At this time, a magnetic field is generated in the heating coil 1, an exciting current flows through the pan 3 by this magnetic field, and the pan 3 itself becomes a heating element by Joule heat. Further, the inverter circuit 2 and the heating coil 1 are cooled by the fan 5. FIG. 4 shows the configuration of the heating coil 1 of this conventional induction heating apparatus. 7 is a copper strand having a diameter of about 0.5 mm, and has an insulating layer 8 on the conductor. Reference numeral 9 denotes a litz wire, which is formed by twisting together a plurality of the copper wires 7 together. The heating coil 1 is a spiral coil configured by winding the Litz wire 9 concentrically in order from the center.
[0003]
Here, when a high-frequency large current is passed through the heating coil 1, the current is collected on the surface by the skin effect, and as a result, the effective resistance value increases and the loss increases. It was set as the structure which twisted such a thin copper strand.
[0004]
[Problems to be solved by the invention]
However, in the above-described conventional configuration, since the number of strands of the heating coil is large and it is necessary to twist them together, a lot of man-hours, time, or costs are required.
[0005]
The present invention is intended to solve such a conventional problem, and an object thereof is to provide a heating coil and an induction heating device with a simpler configuration.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present invention comprises a heating coil for performing induction heating, an inverter circuit for supplying high-frequency power to the heating coil, and a control circuit for controlling the operation of the inverter circuit, The heating coil is composed of a cylindrical conductor, and all the cylindrical conductors are positioned within a skin depth, and heat storage means for storing heat due to loss of the conductor is included in the conductor. To do.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
In the first and second aspects of the present invention, the heating coil for supplying high-frequency power has all the conductors located within the skin depth of a single cylindrical conductor, and the cross-section is all circular and has an edge. Therefore, the current flows uniformly, and the heat of the conductor can be stored by the included heat storage means.
[0008]
【Example】
An embodiment of the present invention will be described with reference to FIGS. In FIG. 1, 10 is a cooker casing, 11 is a pan, 12 is a heating coil, 13 is an inverter circuit, and 14 is a control circuit. Here, the heating coil 12 is configured as shown in FIG. A copper pipe 15 that is a single cylindrical conductor covered with an insulating coating layer 16 and water 17 that is heat storage means included in the copper pipe 15 are spirally wound around a concentric circle to form a coil. It is a thing.
[0009]
The operation of this embodiment will be described below.
[0010]
The inverter circuit 13 is operated in accordance with the cooking process by the output of the control circuit 14. A high frequency current of about 25 kHz is passed from the inverter circuit 13 to the heating coil 10 to generate a magnetic field in the heating coil 12. This magnetic field causes a magnetic excitation current to flow in the pan 11 itself, and the pan 11 itself becomes a heating element due to Joule heat. As a result, the cooking object to be cooked in the pan 11 can be cooked.
[0011]
The cross-sectional shape of the heating coil 12 is an outer diameter of 3 mm, an inner diameter of 1 mm, and a thickness of 1 mm. This water not only stores the heat generated by the copper pipe, but also keeps the ice in the pipe when it is bent into a spiral shape, thereby preventing local deformation inside the pipe when it is bent. .
[0012]
Here, the skin depth of copper is about 0.5 mm at the frequency of 25 kHz. In the case of the copper pipe of the present embodiment, all the copper inside the copper wire is located at a depth of 0.5 mm from the surface, and since there is no edge portion, the current flows uniformly through all the copper pipes. be able to. Moreover, a part of the calorific value due to copper loss can be absorbed by heat absorption at the time of temperature rise of the contained water and heat absorption by latent heat. Therefore, compared with the conventional litz wire coil, the temperature rise of the coil can be suppressed to the same level or less. Further, when the inverter circuit or the heating coil needs to be cooled by the cooling fan, it is not necessary to increase the rotational speed as compared with the conventional art.
[0013]
As described above, the configuration of the heating coil can be further simplified, and the manufacturing process can be simplified and the assemblability can be improved.
[0014]
【The invention's effect】
As described above, according to the first and second aspects of the present invention, a heating coil having a simpler configuration than the conventional one can be realized by using a cylindrical conductor as the configuration of the heating coil and providing heat storage means inside. It is inexpensive, can reduce the manufacturing process, and the effect is great.
[Brief description of the drawings]
FIG. 1 is a block diagram of an induction heating apparatus according to an embodiment of the present invention. FIG. 2 is a detailed view of a heating coil of the induction heating apparatus. FIG. 3 is a block diagram of a conventional induction heating apparatus. Detailed view of heating coil of induction heating device 【Explanation of symbols】
DESCRIPTION OF SYMBOLS 1,12 Heating coil pan 2,13 Inverter circuit 3,11 Pan 4,14 Control circuit 5 Fan 6,10 Case 7 Copper wire 8,16 Insulation coating layer 9 Litz wire wire 15 Copper pipe 17 Heat storage means

Claims (2)

  A heating coil for performing induction heating, an inverter circuit for supplying high-frequency power to the heating coil, and a control circuit for controlling the operation of the inverter circuit, wherein the heating coil is composed of a cylindrical conductor, An induction heating apparatus characterized in that the cylindrical conductor is positioned within a skin depth, and heat storage means for storing heat due to loss of the conductor is included in the conductor.   The induction heating apparatus according to claim 1, wherein the heat storage means of the heating coil is made of water.

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