JP2010287364A - Induction heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction heating device capable of reducing loss of the device and facilitating cooling design. <P>SOLUTION: The induction heating device includes a heating coil 104 constituted by a parallel connection body of an assembled wire portion 106 comprising an assembled wire of a plurality of lead wires insulated from each other and a single wire portion 107 comprising a single lead wire, provided below a top plate 103 and performing induction heating of a heated object 102. Since the single wire portion 107 is provided between the assembled wire portion 106 and the top plate 103 to provide a space distance between the adjacent portions of the single lead wire, induction heating efficiency can be enhanced to reduce heating coil loss, so as to facilitate cooling design. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an induction heating apparatus such as an induction heating cooker used in general homes, offices, restaurants, factories and the like.

  Conventionally, this type of induction heating apparatus has, for example, an induction heating cooker, a heating coil capable of induction heating an object to be heated made of aluminum, copper, or a low magnetic permeability material having an electric conductivity substantially equal to or higher than these. A buoyancy that includes an electric conductor provided between the heating coil and the object to be heated and reduces the buoyancy acting on the object to be heated by the action of the magnetic field generated by the heating coil and the induced current induced in the object to be heated A technique that has a reduction function and arranges a plurality of electrical conductors at intervals is known (see, for example, Patent Document 1).

  In addition, a heating cooker has an induction heating coil and an induction heating element, and a technique of heating by controlling the induction current generated in the induction heating element by supplying a high frequency current to the induction heating coil is known. (For example, refer to Patent Document 2).

  FIG. 3 is a diagram showing a front sectional view of a conventional cooking device body described in Patent Document 2. As shown in FIG. Moreover, FIG. 4 is a figure which shows the structure of the induction heating part 17 of the conventional heating cooker described in patent document 2. As shown in FIG. 5A is a plan view showing the detailed structure of the induction heating unit 17 of the conventional heating cooker described in Patent Document 2, and FIG. 5B is the conventional cooking described in Patent Document 2. The front sectional view which shows the detailed structure of the induction heating part of a cooking device, (c) is the front sectional view which expanded the A section which shows the detailed structure of the induction heating part of the conventional heating cooker described in patent documents 2 .

  In FIG. 5, when the cooked utensil is a low resistance metal material such as aluminum or copper, the induction heating element 17 forms a closed loop by short-circuiting the terminals 17a and 17b. When the closed loop is formed, an induction current flows through the induction heating element 17 due to the magnetic flux generated by the induction heating coil 6 to generate heat. Joule heat generated in the induction heating element 17 indirectly heats the cooked utensil by heat conduction. In addition, when the cooked utensil is a high resistance metal material, the terminals 17a and 17b are opened, so that almost no induced current flows through the induction heating element 17.

Japanese Patent No. 3888190 JP 2007-200722 A

  However, in the conventional configuration, since the cooked utensil is indirectly heated by Joule heat generated in the induction heating element 17 forming a closed loop, if the heat transfer is not successful, the heating efficiency decreases. Or the induction heating element 17 may be melted or damaged due to a temperature rise.

  Moreover, the said conventional structure is the induction | guidance | derivation which flows into a pan bottom by heating the to-be-heated cooking appliance of a low resistance metal material like aluminum and copper especially without using induction heating using the induction heating element 17. The purpose is to prevent the pot floating due to the interaction between current and magnetic flux. Therefore, in the case of a cooked utensil made of a high resistance metal material, the induction heating element 17 does not function.

  The present invention solves the above-mentioned conventional problems, and is constituted by a parallel connection body of an assembly line portion composed of an assembly line of a plurality of conductor wires insulated from each other and a single wire portion composed of a single wire conductor, and is provided below the top plate. Provided with a heating coil provided, the single wire portion is arranged between the collecting wire portion and the top plate by providing a spatial distance between adjacent single wire conductors, thereby increasing induction heating efficiency and reducing heating coil loss, An object of the present invention is to provide an induction heating device that facilitates cooling design.

  In order to solve the above-described conventional problems, an induction heating apparatus of the present invention includes a main body constituting an outer shell, a top plate provided on an upper part of a main body on which an object to be heated is placed, and a set of a plurality of conductors insulated from each other. It is composed of a parallel connection body of an assembly line portion made of wires and a single wire portion made of single wire conductors, and is provided with a heating coil that is provided below the top plate and induction-heats an object to be heated, and the single wire portions are adjacent to each other. A space distance is provided between the conductors, and it is arranged between the assembly line portion and the top plate.

  This makes it possible to increase the induction heating efficiency by increasing the magnetic coupling by reducing the distance between the object to be heated and the heating coil without deteriorating the insulation of the assembly line part due to overheating of the object to be heated, By reducing the heating coil current required for the same heating power, the heating coil loss can be reduced, and the cooling design of the induction heating device is facilitated.

  The induction heating apparatus of the present invention can increase the induction heating efficiency, reduce the heating coil loss, and facilitate the cooling design.

Schematic block diagram of the induction heating apparatus in Embodiment 1 of the present invention Detailed configuration diagram of heating coil 104 of induction heating device in Embodiment 1 of the present invention Front sectional view of a conventional cooking device The figure which shows the structure of the induction heating part of the conventional heating cooking appliance. (A) Top view which shows detailed structure of induction heating part of conventional heating cooker (b) Front sectional view which shows detailed structure of induction heating part of conventional heating cooker (c) Induction heating of conventional heating cooker Front sectional view enlarging part A showing the detailed structure of the part

  1st invention consists of the main body which comprises an outer shell, the top plate provided in the upper part of the said main body which mounts a to-be-heated material, the assembly line part which consists of the assembly line of several conducting wires mutually insulated, and a single wire conductor A heating coil for inductively heating an object to be heated, which is configured by a parallel connection body with a single wire portion and provided below the top plate, and the single wire portion has a space distance between adjacent single wire conductors It is arranged between the line portion and the top plate.

  As a result, since the single wire portion of the heating coil is provided between the assembly wire portion and the top plate, the distance between the object to be heated and the heating coil will be close, and magnetic coupling will be enhanced, which is efficient. In addition to realizing induction heating, it is possible to reduce the heating coil loss by reducing the heating coil current necessary for making the induction heating power generated in the object to be heated constant.

On the other hand, since the single wire portion has a spatial distance between the adjacent single wire conductors, for example, even if the heat transfer from the object to be heated becomes excessive and the temperature of the single wire portion rises, between the adjacent single wire conductors This will not cause deterioration of insulation.

  Furthermore, since the heating coil is constituted by the parallel connection body of the collecting wire portion and the single wire portion, the heating coil current is divided and flows into the collecting wire portion and the single wire portion, and each loss is suppressed.

  Therefore, according to the configuration of the present invention, efficient induction heating can be realized and the cooling design of the induction heating device can be facilitated.

  In the second invention, in particular, in the first invention, the single line portion has a larger impedance than the collective line portion.

  When the heating coils are connected in parallel, the heating coil current that affects the heating coil loss flows more when the impedance (resistance and inductance) is smaller. Therefore, when the heating coil current is constant, the heating coil current toward the larger impedance decreases.

  According to the configuration of the present invention, for example, the impedance of the single wire portion is increased by setting the number of turns larger than that of the collective wire portion. Further, since the single wire portion and the collective wire portion are connected in parallel, the heating coil current flowing through the single wire portion is smaller than the heating coil current flowing through the collective wire portion. Therefore, it is possible to reduce the loss of the single wire portion compared to the assembly wire portion, and the cooling design of the induction heating device can be facilitated.

  In addition, by increasing the number of turns of the single wire portion closer to the object to be heated than the assembly line portion and increasing the impedance, it is possible to increase the magnetic coupling between the object to be heated and the heating coil. It becomes possible to obtain a constant heating power for the object to be heated.

  In the third invention, in particular, the single wire portion of the first invention is thermally connected to an object to be heated.

  Since the single wire portion has a spatial distance between adjacent single wire conductors, even if the temperature of the single wire portion does not exceed the melting point of the metal used for the single wire, the operation as an induction heating device is not affected. Absent.

  Therefore, when the object to be heated is not abnormally heated, the heating efficiency can be improved by transferring the heat generated in the single wire portion to the object to be heated thermally connected to the single wire portion. It becomes possible.

  The connection of the single wire portion and the object to be heated is, for example, a configuration in which the single wire portion is pressed from the heating coil side of the top plate so that the heat generated in the single wire portion can be transmitted to the object to be heated via the top plate. Is to do.

  Further, since the heat generated in the single wire portion is transmitted to the object to be heated, the temperature rise in the single wire portion is alleviated, so that the cooling design of the induction heating device can be further facilitated.

  In particular, according to a fourth invention, in the third invention, there is provided a heating coil support part for supporting the heating coil, and an insulating part fixed to the heating coil support part located between the collecting wire part and the single wire part of the heating coil. The single wire portion is provided on the top plate side of the insulator.

  In order to improve the effect of pressing the single wire portion from, for example, the heating coil side of the top plate and thermally connecting it to the object to be heated, it is necessary to press the single wire portion evenly against the top plate.

  According to the configuration of the present invention, since the single wire portion is provided on the top plate side of the insulating portion fixed to the heating coil support portion, no deflection or the like occurs. Therefore, the single wire portion can be pressed evenly against the top plate, and heat transfer from the single wire portion to the object to be heated can be improved.

  Furthermore, since the insulating portion is fixed between the single wire portion and the collective wire portion, there is no fear of deterioration of electrical insulation between the single wire portion and the collective wire portion, and a highly reliable induction heating device can be obtained. I can do it.

  In a fifth aspect of the invention, in particular, in the fourth aspect of the invention, a heat insulating portion is provided, and the heat insulating portion is provided between the single wire portion and the insulating portion.

  Thus, according to the configuration of the present invention, the amount of heat transmitted from the single wire portion to the insulating portion, the heating coil support portion, and the collecting wire portion is limited, and the heat can be more easily transmitted to the top plate side. Therefore, it is possible to further improve the heat transfer from the single wire portion to the object to be heated.

  In addition, heat generation and heat radiation to the assembly line portion are generated by heat generation of the single wire portion, and there is no concern that the temperature of the assembly line portion rises and the insulation deteriorates, so that a highly reliable induction heating device can be obtained. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a schematic configuration diagram of an induction heating apparatus according to a first embodiment of the present invention.

  In FIG. 1, a top plate 103 on which an object to be heated 102 is placed is provided on an upper portion of a main body 101 that constitutes an outline of the induction heating apparatus. Below the top plate 103, inside the main body 101, a heating coil 104 for induction heating the object to be heated 102 is provided.

  An inverter 105 is connected to the heating coil 104. The inverter 105 has a switching element or the like (not shown) inside, and supplies a high frequency current of 20 kHz to 100 kHz to the heating coil 104 by switching a supplied power source (not shown). The heating coil 104 generates a high-frequency magnetic field by a high-frequency current and induction-heats the article to be heated 102.

  The heating coil 104 is constituted by a parallel connection body of an assembly wire portion 106 made of litz wire, which is an assembly wire of a plurality of insulated wires, and a single wire portion 107 made of a single wire conductor, which is a flat copper wire. ing.

  The distance from the top plate 103 side surface of the assembly line portion 106 to the bottom surface of the object to be heated 102 is 8 mm, and the distance from the top plate 103 side surface of the single wire portion 107 to the bottom surface of the object to be heated 102 is 4 mm. .

  The distance from the surface of the single wire portion 107 on the top plate 103 side to the bottom of the object to be heated 102 is 4 mm. The thickness of the top plate 103 is 4 mm. As will be described later, the single wire portion 107 is on the heating coil 104 side of the top plate 103. It is because it is contact | abutted to.

  The assembly line portion 106 of the heating coil 104 is fixed on the heating coil support portion 108 that supports the heating coil 104 by a thermosetting adhesive such as silicone.

  On the lower surface of the heating coil support portion 108 (on the side surface opposite to the top plate 103), eight rod-shaped ferrites 109 that are radially magnetic are arranged. The ferrite 109 transmits a high-frequency magnetic field generated from the heating coil 104 to the object to be heated 102 without leaking as much as possible to prevent induction heating of parts other than the object to be heated 102 or leakage to the outside of the main body 101. It is provided for the purpose.

  A terminal portion 111 provided on the outer periphery of a doughnut-shaped insulating portion 110 having a thickness of 1 mm with a slit in part is fixed to the outer peripheral portion of the heating coil support portion 108. The insulating part 110 is made of mica having sufficient heat resistance.

  The insulating portion 110 is fixed so as to be positioned between the collective line portion 106 and the single wire portion 107 of the heating coil 104. This slit is for absorbing the deformation generated in the mica which is the insulating portion 110 due to the temperature rise, and making it easy to maintain the planar shape.

  On the top plate 103 side of the insulating part 110, a donut-shaped heat insulating part 112 having a thickness of 0.5 mm made of a ceramic fiber sheet having a heat insulating effect is arranged.

  Further, a single wire portion 107 is placed further on the top plate 103 side of the heat insulating portion 112, and the heating coil support portion 108, the insulating portion 110, and the heat insulating portion 112 make the heating coil 104 side of the top plate 103 from the inside of the main body 101. It is pressed against the surface.

  That is, the single line portion 107 is arranged between the collective line portion 106 and the top plate 103.

  FIG. 2 shows a detailed configuration diagram of the heating coil 104 of the induction heating apparatus according to the first embodiment of the present invention.

  In FIG. 2, the collecting wire portion 106 and the single wire portion 107 are each wound in a donut shape to form a heating coil 104. The number of turns is 20 turns for the collective line portion 106 and 30 turns for the single wire portion 107, and the impedance of the single wire portion 107 is larger than that of the collective line portion 106. The inner and outer diameters of the single wire portion 107 and the collective wire portion 106 are substantially the same, and are 50 mm and 180 mm, respectively.

  The collective line portion 106 is composed of two donut-shaped portions having the same circular center in order to make the heat distribution of the object to be heated 102 uniform. In each of the two donut-shaped portions, there is no space gap between adjacent turns.

  Further, the litz wire of the assembly line portion 106 has a configuration in which 60 copper wires having a diameter of 0.3 mm whose surfaces are enamel-coated are twisted, and the thickness thereof is about 5 mm. Since a litz wire is used, it is possible to mitigate the increase in resistance due to the skin effect and proximity effect that occur when a high-frequency current flows.

  The single wire portion 107 is composed of a flat copper wire having a width of 1 mm and a thickness of 0.8 mm. In addition, a spatial distance of about 1 mm is provided between adjacent single wires. Since insulation between the adjacent single wire conductors is ensured, the surface coating treatment of the single wire conductors is not performed.

  The collective line portion 106 and the single wire portion 107 are connected to each other so as to be electrically in parallel. Specifically, the outer peripheral side terminal of the collective line portion 106 and the outer peripheral side terminal of the single line portion 107 are connected to each other and connected to the inverter 105, and the inner peripheral side terminal of the collective line portion 106 and the inner peripheral side terminal of the single line portion 107 are connected. Are similarly connected to each other and connected to the inverter 105.

  That is, when viewed from the inverter 105, the collective line portion 106 and the single wire portion 107 are connected in parallel to constitute the heating coil 104.

  In addition, the winding direction is adjusted so that when the current flows through the collective line portion 106 and the single wire portion 107, the directions of the currents flowing in the respective portions are the same. Specifically, when the heating coil 104 is viewed from the top plate 103 side, both the collecting wire portion 106 and the single wire portion are wound clockwise.

  About the induction heating apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  First, the inverter 105 rectifies a supplied power supply (not shown), and then converts it to a high-frequency voltage by an on / off operation of an included switching element (not shown). The high frequency voltage is supplied to the heating coil 104 connected to the inverter 105, and a high frequency current flows.

  A high-frequency magnetic field is generated by the high-frequency current flowing through the heating coil 104, an eddy current is induced inside the heated object 102 placed above the heating coil 104, and the heated object 102 is heated by Joule heat.

  At this time, the single wire portion 107 of the heating coil 104 is pressed against the side surface of the heating coil 104 of the top plate 103, and the distance from the object to be heated 102 is minimized. Therefore, the magnetic field generated from the single wire portion 107 can easily reach the object to be heated 102 without waste, the magnetic coupling between the object to be heated 102 and the single wire portion 107 is enhanced, and induction heating can be performed efficiently. Is possible.

  In order to efficiently induction-heat the object to be heated, it is effective to increase the magnetic coupling between the object to be heated and the heating coil. Increasing magnetic coupling means efficiently transmitting one magnetic energy to the other.

  As specific means, the distance between the object to be heated and the heating coil is made closer, the leakage magnetic flux leaking without contributing to induction heating is reduced, or the number of turns of the heating coil is increased equivalently. There are methods such as increasing the area of the object to be heated as seen from the heating coil.

  In the present embodiment, by increasing the magnetic coupling between the object to be heated and the heating coil, efficient induction heating is realized, and the heating coil current required to make the induction heating power generated in the object to be heated constant is set. It becomes possible to reduce heating coil loss.

  However, simply moving the heating coil closer to the object to be heated also brings the distance between the top plate and the heating coil closer, and the heat generated in the object to be heated also affects the heating coil.

  For example, in cooking such as stir-fried vegetables, the bottom surface of an object to be heated (such as a frying pan) rises to about 200 to 300 ° C., so the heating coil temperature is raised through the top plate. In addition, when a small amount of oil is used in cooking fried food such as tempura, overheating of the oil is likely to occur, and the heating coil temperature is similarly increased.

Furthermore, the circulation of the cooling air flowing in the space between the top plate and the heating coil is hindered, so that sufficient cooling cannot be performed and the heating coil temperature rises.

In such a case, if the heating coil temperature exceeds the heat resistance temperature, the insulating coating between turns of the heating coil is deteriorated and insulation cannot be maintained, leading to breakage of the heating coil or the induction heating device.
In the present embodiment, since the single wire portions are provided with a spatial distance between the adjacent single wire conductors, for example, even if the heat transfer from the object to be heated becomes excessive and the temperature of the single wire portion rises, the adjacent single wires There is no degradation of insulation between conductors.

  Further, the single wire portion 107 uses copper having a very high melting point (for example, about 1000 ° C. with pure copper). Further, a spatial distance is provided between the adjacent single conductors, and no special insulation coating treatment is provided.

  When the bottom of the object to be heated 102 is 200-300 ° C. in cooking such as stir-fried vegetables, or when a small amount of oil is used in cooking fried food such as tempura, etc. It is assumed that the temperature of the single wire portion 107 is increased by the heat generated by the article to be heated 102 through the top plate 103. In the case of the assembly wire, since it is composed of a plurality of conductive wires insulated from each other, the insulation coating deteriorates at a high temperature, and local heat generation at the deteriorated portion becomes remarkable. As a result, the conductor may be deteriorated or damaged.

  However, in the case of a single wire, there is no deterioration of the insulation coating due to high temperature, and since there is little damage to the conductor due to no local heat generation, it has sufficient heat resistance and does not affect the operation of the induction heating device .

  In addition, when the object to be heated 102 is boiled and the bottom surface temperature does not increase so much, such as cooking with boiled food, the heat generated in the single wire portion 107 is transferred to the object to be heated 102 through the top plate 103, thereby improving the heating efficiency. Can be improved.

  Further, since the heat insulating portion 112 is arranged on the side of the collective line portion 106 of the single wire portion 107, heat transfer to the heated object 102 of the single wire portion 107 is further promoted, and the heat influence on the collective line portion 106 is reduced. Less.

  Further, since the heat generated in the single wire portion 107 is transmitted to the object to be heated 102, the temperature rise in the single wire portion 107 is also mitigated.

  The collecting wire portion 106 and the single wire portion 107 of the heating coil 104 are connected in parallel. Since the single wire portion 107 is a single wire conductor, the increase in high-frequency resistance due to the skin effect and the proximity effect is larger than that of the collective wire portion 106.

  However, since the number of turns is set to be large, the single wire portion 107 as a whole has a larger impedance (resistance, inductance) than the collective wire portion 106, and a flowing current is small. When a high-frequency current (20 kHz to 100 kHz) used for induction heating is supplied to a single-wire heating coil, the single-wire heating coil has a higher-frequency resistance than a heating coil composed of a plurality of conductor wires (for example, litz wire). Is extremely high, the loss and heat generation of the heating coil itself is large, and the induction heating efficiency is lowered.

  In the present embodiment, the single wire portion 107 is pressed evenly against the side surface of the heating coil 104 of the top plate 103 by the insulating portion 110 and the heating coil support portion 108 via the heat insulating portion 112.

  Therefore, the heat generated by the single wire portion 107 is efficiently transmitted to the object to be heated 102.

  Furthermore, since the insulating portion 110 is fixed between the single wire portion 107 and the collective wire portion 106, it is easy to ensure sufficient insulation between the single wire portion 107 and the collective wire portion 106. Further, since a space of about 1.5 mm is vacant between the insulating portion 110 and the collective line portion 106, cooling air can pass through, and the collective line 106 can be easily cooled.

  In the present embodiment, the single wire portion 107 is a copper wire. However, the present invention is not limited to this, and any wire may be used as long as it has sufficient heat resistance as compared with the abnormal temperature of the article to be heated 102.

  For example, aluminum which is a low-resistance nonmagnetic metal can be cited as an example. In the case of copper, the surface may be rusted, but in the case of aluminum, a natural oxide layer is formed on the surface, and the surface changes little, and a high degree of contact with the top plate 103 can be maintained. Aluminum is less expensive than copper.

  Further, the single wire portion 107 may be a multilayer of a plurality of flat conductive wires. In this case, since the flat conductor can be mass-produced at high speed by a punching method, the manufacture becomes easy.

  Further, if a high thermal conductive material is inserted between the top plate 103 and the single wire portion 107 in order to further transfer the heat generated in the single wire portion 107 to the object to be heated 102, unevenness of the single wire portion 107 against the top plate 103 can be reduced. It is possible to reduce.

  As described above, the induction heating device according to the present invention can reduce the loss of the device and facilitates the cooling design. Therefore, as an induction heating cooker, the induction heating type water heater, the induction heating type It can also be applied to applications such as irons or other induction heating type heating devices.

DESCRIPTION OF SYMBOLS 101 Main body 102 Object to be heated 103 Top plate 104 Heating coil 106 Assembly line part 107 Single wire part 108 Heating coil support part 110 Insulation part 112 Heat insulation part

Claims (5)

Parallel connection of the main body constituting the outer shell, the top plate provided on the upper part of the main body on which the object to be heated is placed, and the assembly line portion composed of a plurality of insulated wires and the single wire portion composed of a single wire And a heating coil for induction heating of the object to be heated, the single wire portion having a spatial distance between adjacent single wire conductors, and the assembly wire portion and the top. Induction heating device placed between the plates. The induction heating device according to claim 1, wherein the single wire portion has a larger impedance than the collective wire portion. The induction heating device according to claim 1, wherein the single wire portion is thermally connected to an object to be heated. A heating coil supporting portion that supports the heating coil; and an insulating portion that is fixed to the heating coil supporting portion that is positioned between a collecting wire portion and a single wire portion of the heating coil, and the single wire portion is a portion of the insulating portion. The induction heating device according to claim 3 provided on the top plate side. The induction heating device according to claim 4, further comprising a heat insulating portion, wherein the heat insulating portion is provided between the single wire portion and the insulating portion.

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