WO2012056957A1 - Induction heating device and heating system equipped with same - Google Patents

Abstract

Provided are: an induction heating device which cannot be broken upon the irradiation with microwave or during the use at a higher temperature; and a heating system equipped with the induction heating device. The induction heating device (1) comprises: a ring-shaped electrically conductive body (2) which is composed of an electrically conductive material such as a metal having low electrical resistance, such as aluminum and copper; a coil (3) which is formed by winding a coated copper wire several times; a magnetic body (4) which is so arranged that a high-frequency magnetic flux that is generated upon the conduction of a high-frequency current to the coil (3) can form a magnetic circuit that interlinks with the ring-shaped electrically conductive body (2); and a high-frequency power supply (5) which can supply a high-frequency current to the coil (3). The ring-shaped electrically conductive body (2) comprises a heating unit (25) adjacent to which an object (6) to be heated is placed and a power supply unit (24) at which the high-frequency magnetic flux that has been generated by the coil (3) interlinks, and the magnetic body (4) is so arranged that high-frequency magnetic flux generated by the coil (3) can interlink at the power supply unit (24) in the ring-shaped electrically conductive body (2).

Description

Induction heating apparatus and heating system using the same

The present invention relates to an induction heating device, and more particularly, to an induction heating device for induction heating by generating an eddy current in an object to be heated and a heating system using the induction heating device.

Induction heating devices are widely used in cooking devices such as IH cooking heaters and electric rice cookers. In general, these induction heating devices use a coil in which a coated copper wire is spirally wound a plurality of times. A high frequency magnetic field generated around the coil is applied to the coil by applying a high frequency current of 20 to 100 kHz to the coil. An eddy current is passed through the object to be heated, and the object to be heated is heated by Joule heat generated by the eddy current. There has been proposed a heating system in which such an induction heating device is combined with a microwave oven or microwave oven which is a microwave heating (dielectric heating) device.

In the conventional heating system using induction heating and microwave heating, the bottom of the heating chamber where high-frequency dielectric heating is performed is composed of a metal net made of a non-magnetic material, and electromagnetic induction for electromagnetic induction heating is formed under the metal net. The coil is arranged. Thus, the microwave is cut off by the metal net to protect the coil from the microwave, and the magnetic flux generated by the coil can pass through the metal net to inductively heat the object to be heated (see, for example, Patent Document 1).

On the other hand, another heating system has an induction heating coil in which a rectangular electric soft copper wire without an insulating coating is spirally formed in the vicinity of the bottom wall surface of a heating chamber irradiated with microwaves. The flat electric soft copper wire is fixed in a state of being insulated by a high heat-resistant insulator such as ceramic wool. Therefore, the heat resistant temperature does not become a problem as in the case of a general coated wire, and the induction heating coil does not need to be cooled. The induction heating coil itself can also be handled as a heater, and the overall efficient thermal design can be performed. Furthermore, even if the heating chamber is filled with microwaves, the surface area exposed to microwaves is small, so the temperature of the induction heating coil is small, and it can withstand use at high temperatures, and coexist with the microwave function. It is possible (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 4-65097 JP-A-8-138864

In the heating system described in Patent Document 1, as a result of microwaves being blocked by a non-magnetic metal net, damage to the coating material of the induction heating coil due to the microwave reaching the induction heating coil, or winding of the induction heating coil. Spark discharge due to microwave irradiation does not occur between the lines. However, when the induction heating coil is operated, the non-magnetic metal net is also induction heated, so that there is a problem that the efficiency of induction heating is lowered. In addition, as a result of induction heating of the metal net by the high-frequency magnetic field from the induction heating coil, the metal net may thermally expand and deform, and further, spark discharge may occur in the metal net due to microwave irradiation, and the metal net may be damaged. There was a problem that there was.

Moreover, although the heating system described in Patent Document 2 is formed of a rectangular electric soft copper wire in a spiral shape with a highly heat-resistant insulator, spark discharge is generated between the windings when irradiated with microwaves. There was a problem.

Accordingly, the present invention has been made to solve the above-described problems, and by providing a novel induction heating means, electrical insulation between windings, which has been a problem with conventional winding type coils, has been made. An induction heating apparatus that solves problems such as securing and spark discharge between windings due to microwave irradiation is obtained. Moreover, the heating system using this induction heating apparatus is obtained.

An induction heating apparatus according to the present invention includes a coil, a high-frequency power source that supplies a high-frequency current to the coil, and a one-turn annular conductor that constitutes an electrical closed circuit. It has a heating part that induction-heats an object, and a power supply part that interlinks the high-frequency magnetic flux generated by the coil, and the magnetic material is arranged so that the high-frequency magnetic flux generated by the coil is interlinked by the power supply part of the annular conductor Is.

According to the present invention, there is an effect that an object to be heated can be inductively heated by a high-frequency magnetic flux generated around the annular conductor by causing an induction current to flow through the annular conductor constituting an electrical closed circuit.

It is a perspective view which shows the induction heating apparatus which concerns on Embodiment 1 of this invention. It is a perspective view which shows the induction heating apparatus which concerns on Embodiment 1 of this invention. It is a perspective view which shows the operation state of the induction heating apparatus which concerns on Embodiment 1 of this invention. It is sectional drawing in the surface A in FIG. It is sectional drawing which shows the other form of FIG. It is sectional drawing which shows the other form of FIG. It is sectional drawing which shows the other form of FIG. It is a perspective view which shows the induction heating apparatus of the other form which concerns on Embodiment 1 of this invention. It is sectional drawing in the surface B in FIG. It is a perspective view which shows the induction heating apparatus of the other form which concerns on Embodiment 1 of this invention. It is a front view which shows the heating system which concerns on Embodiment 2 of this invention. It is sectional drawing seen from the front which shows the heating system which concerns on Embodiment 2 of this invention. It is sectional drawing which shows arrangement | positioning of the annular conductor of the heating system which concerns on Embodiment 2 of this invention, a magnetic body, and a magnetic-shield board. It is a front view which shows the heating system which concerns on Embodiment 3 of this invention. It is sectional drawing seen from the front which shows the heating system which concerns on Embodiment 3 of this invention. It is sectional drawing seen from the front which shows the heating system of the other form which concerns on Embodiment 3 of this invention. It is the disassembled perspective view which showed the heating system which concerns on Embodiment 4 of this invention. It is sectional drawing seen from the front which shows the heating system which concerns on Embodiment 4 of this invention. It is a front view which shows the heating system which concerns on Embodiment 5 of this invention. It is sectional drawing seen from the front which shows the heating system which concerns on Embodiment 5 of this invention. It is sectional drawing seen from the side surface which shows the heating system which concerns on Embodiment 5 of this invention. It is a perspective view which shows the structure of the coil and magnetic body of the induction heating apparatus which concern on Embodiment 5. FIG. It is the perspective view of the principal part seen from the back which shows the other heating system which concerns on Embodiment 5 of this invention. It is sectional drawing seen from the side surface which shows the other heating system which concerns on Embodiment 5 of this invention. It is an expanded view which shows the structure of the cyclic | annular conductor of the other induction heating apparatus which concerns on Embodiment 5. FIG.

DESCRIPTION OF SYMBOLS 1 Induction heating apparatus 2 Annular conductor 3 Coil 4 Magnetic body 5 High frequency power supply 6 Heated object 7 Cutting 8 Heating system 9, 31 Case 10 Heating chamber 11 Right side wall 12 Left side wall 13 Rear wall 14 Ceiling wall 15 Bottom wall 16 Hole 17a Magnetron 17b Microwave emission hole 17c Waveguide 18 Magnetic shield 19 Magnetic body (ferrite core)
24 Power supply unit 25 Heating unit 26 Oven container 26a Container unit 26b Cover unit 32 Top plate 36a Pan 36b Frying pan 42 Groove unit 43 Convex unit 44 Insulating plate 45 Heater 46a, 46b Shelf unit 50 Grease tray 51 Grill net 52a, 52b Insulating material 53 Door 54 Slide rail 55 Magnetic shield 56 Air cooling fan 60 Foodstuff

Hereinafter, an induction heating apparatus and a heating system according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the following description, terms indicating direction and position (for example, “up”, “down”, “right”, “left”, etc.) are used for convenience, but these are for facilitating understanding of the invention. Therefore, the technical scope of the present invention should not be limitedly interpreted by these terms. Moreover, in the following description, the same code | symbol is attached | subjected to the same or similar structure contained in several embodiment.

Embodiment 1 FIG.
FIG. 1 is a perspective view showing an induction heating apparatus according to Embodiment 1 of the present invention. 2 is a perspective view showing the induction heating device viewed from a direction different from that in FIG. An induction heating apparatus 1 according to Embodiment 1 includes an annular conductor 2 formed of a conductive material such as a metal having a low electrical resistance such as aluminum or copper, a coil 3 formed by winding a coated copper wire a plurality of times, and a coil 3 includes a magnetic body 4 arranged so as to constitute a magnetic circuit in which a high-frequency magnetic flux generated when a high-frequency current is passed through 3 is linked to the annular conductor 2, and a high-frequency power source 5 for passing a high-frequency current through the coil 3. Is done.

For example, the annular conductor 2 is formed into an annular shape that forms an electrically closed circuit by cutting or pressing an aluminum plate, a copper plate, or the like, and then the annular conductor 2 is perpendicular to the middle of the length direction. And is formed into an L shape. Specifically, the annular conductor 2 includes a horizontal portion 20a having an upper surface on which an object to be heated (both not shown) is placed with an insulating material interposed therebetween, and a vertical portion 20b extending upward from one end of the horizontal portion 20a. And have. As will be described later, an induced current having the same frequency (driving frequency) as the high-frequency current supplied to the coil 3 flows through the annular conductor 2, so that the skin depth at the driving frequency is at least twice in consideration of the skin effect. It is preferable to form the plate with a thickness of 2 mm because the electrical resistance at the driving frequency of the annular conductor 2 can be reduced. For example, the skin depth at 20 kHz is about 0.57 mm for aluminum and about 0.47 mm for copper, and the skin depth at 50 kHz is about 0.36 mm for aluminum and about 0.30 mm for copper. If the plate thickness of the annular conductor 2 is 1.14 mm or more for aluminum and 0.74 mm or more for copper, the electrical resistance of the annular conductor 2 can be minimized at a driving frequency of 20 to 100 kHz. The plate thickness of the body 2 can be determined regardless of the driving frequency. In addition, even if the annular conductor 2 is formed with a plate thickness thinner than the above-mentioned plate thickness, only the power consumption in the annular conductor 2 is increased, and the effect of the present invention is not hindered.

Similarly, even if the annular conductor 2 is formed of a conductive material such as a metal other than aluminum or copper, only the power consumption in the annular conductor 2 changes, and the effect of the present invention is not hindered. The annular conductor 2 shown in FIGS. 1 and 2 is obtained by processing an aluminum plate or a copper plate into an annular shape and then bending it into an L shape. However, the outer shape is not limited to this and may be any shape. With respect to this, some shapes are shown in the following embodiments with application examples. The annular conductor 2 is not limited to one formed by processing a plate-like member, and may be one formed by processing a rod-like member or one formed by casting.

A coil 3 formed by winding a conductive wire in a flat plate shape is disposed behind the vertical portion 20b of the annular conductor 2. As shown in the figure, a part of the coil bundle (straight line part) of the coil 3 is arranged behind one vertical portion 20b of the annular conductor 2, and another coil bundle part (straight line part) of the coil 3 is annular conductive. Arranged behind the other vertical portion 20b of the body 2. The coil 3 can be formed, for example, by winding a so-called litz wire made of 36 coated copper wires obtained by coating a copper wire having a diameter of about 0.3 mm with a resin into a flat plate shape 12 times. In addition, the diameter and the number of twists of the copper wire (element wire) of the litz wire used for the coil 3 are not limited to this, and for example, a simple coated copper wire may be used instead of the litz wire. Of course, an aluminum wire may be used instead of a copper wire. Further, the number of turns of the coil is not limited to this, and any number of turns can be set according to the design of the induction heating device 1. Furthermore, the shape of the coil 3 is not limited to a flat plate shape, and may be any shape as long as the high-frequency magnetic flux generated by the coil 3 is linked to the annular conductor 2.

As shown in the figure, one vertical portion 20b of the annular conductor 2 and the outside of a part of the coil bundle (straight portion) of the coil 3, and another vertical portion 20b of the annular conductor 2 and another coil of the coil 3 are shown. Magnetic bodies 4 formed in a square cylindrical shape are disposed so as to surround the outside of the bundle (straight line portion). In the present embodiment, a portion surrounded by the magnetic body 4 in the vertical portion 20b of the annular conductor 2, that is, a portion placed under the influence of the high-frequency magnetic flux generated by the coil 3 is referred to as a “feeding portion 24”. . The magnetic body 4 may be arranged so as to link with the coil 3 and also with the annular conductor 2. For the magnetic body 4, a ferrite core similar to the ferrite core used in an induction heating device such as an IH cooking heater can be used. Alternatively, an iron core formed by laminating silicon steel plates with a thickness of about 0.1 mm, an amorphous core formed of an amorphous thin film, and a magnetic powder such as iron as a main component and formed by compaction or resin fixation. Other magnetic materials such as a dust core may be used. For the magnetic body 4, for example, a ferrite core having a thickness of 5 mm is used. An insulating layer (not shown) is disposed between the magnetic body 4 and the coil 3 and the annular conductor 2 to be electrically insulated. The insulating layer may be an insulator that also serves as a heat insulating material such as glass wool or ceramic wool, and the gap between the coil 3 and the annular conductor 2 may have an insulating structure by an air layer. It may be an insulating structure by circulating air. Further, an insulator may be formed on the surface of the annular conductor 2, and for example, an oxide may be formed on the surface of aluminum or copper. In particular, when the annular conductor 2 is formed of aluminum, a strong alumina layer can be easily formed on the aluminum surface by anodization (alumite treatment), and this may be used as an insulating layer.

The end of the conducting wire of the coil 3 is connected to a high frequency power source 5 so that high frequency power of, for example, 20 kHz to 100 kHz is supplied from the high frequency power source 5 to the coil 3. The high frequency power source 5 can be the same as that used in a general induction heating apparatus such as an IH cooking heater. That is, a full bridge circuit, a half bridge circuit, or a monolithic resonance type circuit using a semiconductor switching element such as an IGBT or a MOSFET can be used (detailed description of the circuit is omitted).

FIG. 3 is an operation explanatory diagram of the induction heating apparatus 1 shown in FIG. 4 is a cross-sectional view taken along plane A in FIG. Although the magnetic body 4 is omitted in FIG. 3, the magnetic body 4 is arranged as shown in FIGS. 1 and 2. FIG. 3 also shows a rectangular dish-shaped object 6 to be heated that is induction-heated by a high-frequency magnetic flux generated by an induced current flowing through the annular conductor 2. A portion of the annular conductor 2 where the object to be heated 6 is disposed in the vicinity of the horizontal portion 20a is referred to as a “heating portion 25”. The object to be heated 6 is selected and used by the user of the induction heating apparatus 1 and is not an essential requirement of the present invention, but the purpose of the present invention is to induction-heat the object 6 to be heated.

The object to be heated 6 is preferably formed of a ferromagnetic metal material such as iron or magnetic stainless steel, which is suitable for general induction heating devices such as IH cooking heaters. However, the volume resistivity of nonmagnetic stainless steel or the like is preferable. It may be a conductive material such as a non-magnetic metal material or a carbon material having a large volume, and even a metal material having a small volume resistivity such as aluminum or copper can be induction-heated by increasing the drive frequency to approximately 60 kHz or more. A metal material having a small volume resistivity such as aluminum or copper may be used. That is, any material may be used as long as it is a material that is induction-heated by a conventionally known general induction heating apparatus.

Furthermore, the shape of the article to be heated 6 can also be any shape that is carried out by a person skilled in the art using a general induction heating apparatus. Although not shown, an insulator is interposed between the annular conductor 2 and the object to be heated 6, and the annular conductor 2 and the object to be heated 6 are electrically insulated. The insulator may be a glass plate or a ceramic plate disposed between the annular conductor 2 and the object 6 to be heated. When the temperature for heating the object 6 is low, a resin plate such as plastic is used. It may be. Moreover, the insulating film formed in the surface of one or both of the cyclic | annular conductor 2 and the to-be-heated material 6 may be sufficient. The insulating film may be provided by coating an insulating material or by forming an oxide film on the surface of the annular conductor 2 or the object to be heated 6. Since the annular conductor 2 is formed of a one-round conductor, when an induced current flows through the annular conductor 2 unlike a coil formed of a plurality of turns like a general induction heating device coil. The generated voltage is low (several tens of volts or less). Therefore, even a thin insulator such as a paint or an oxide film can sufficiently ensure insulation.

Next, the operation will be described. When a high frequency current (coil current) is supplied from the high frequency power source 5 to the coil 3, a high frequency magnetic flux φ 1 is generated around the coil 3. The high-frequency magnetic flux φ1 mainly passes through the magnetic body 4 having a small magnetic resistance. Since the magnetic circuit composed of the magnetic body 4 is arranged so as to be linked to the annular conductor 2, the high-frequency magnetic flux φ 1 is linked to the annular conductor 2. As a result, an induced current flows through the annular conductor 2 by electromagnetic induction. That is, the induction heating apparatus 1 shown in FIG. 1 and FIG. 2 has the same operating principle as a transformer, and if the coil 3 is a primary winding having N turns, the annular conductor 2 becomes a secondary winding having 1 turns. , N: 1 transformer. Therefore, a large current larger than the coil current flows through the annular conductor 2 at the same frequency as the coil current. When a high-frequency induced current flows through the annular conductor 2, a high-frequency magnetic flux φ2 is generated around the annular conductor 2 as shown in FIG. Since the high-frequency magnetic flux φ2 passes through the object to be heated 6 disposed in the vicinity of the annular conductor 2, an eddy current is generated in the object to be heated 6, and the object to be heated 6 is induction-heated by the Joule heat of the eddy current. Is done.

Further, the annular conductor 2 and the object to be heated 6 may be insulated by an extremely thin insulator such as an oxide film. In this case, since the distance between the annular conductor 2 and the object to be heated 6 can be made extremely small, the high-frequency magnetic flux φ2 generated around the annular conductor 2 can efficiently reach the object to be heated 6 and the efficiency of induction heating can be increased. Furthermore, Joule heat generated by its own electrical resistance when an induced current flows through the annular conductor 2 can also be used for heating the article 6 to be heated.

In addition, even when the heated object 6 to be heated by induction is higher in temperature than the annular conductor 2, the annular conductor 2 generates heat due to Joule heat, so that the heated object 6 and the annular conductor 2 are heated. The temperature difference becomes smaller. That is, the amount of heat dissipated from the object to be heated 6 through the annular conductor 2 is smaller than the amount of heat dissipated from the object to be heated 6 through the annular conductor 2 if the annular conductor 2 does not generate heat. Even when the object to be heated 6 is at a higher temperature than the annular conductor 2, it can be said that the heat generated by the annular conductor 2 is used for heating the object to be heated 6.

As described above, the induction heating apparatus 1 according to Embodiment 1 of the present invention is a magnetic flux that induction-heats an object to be heated by a coil that is produced by winding a coated copper wire a plurality of times as in a conventional general induction heating apparatus. Therefore, it is not necessary to cool the annular conductor 2. For coils manufactured by winding a conventional coated copper wire multiple times, it is necessary to keep the coil temperature below the heat resistance temperature of the coating material covering the copper wire (180 to 200 ° C or less). The cooling was done more actively. However, in the case of the annular conductor 2, for example, when the annular conductor 2 is made of aluminum, the heat resistant temperature becomes the melting point of aluminum and can be used up to about 700 ° C. without any problem.

When the annular conductor 2 is made of copper having a higher melting point, it can be used up to a higher temperature. Therefore, in the induction heating apparatus 1 according to Embodiment 1 of the present invention, the cooling means for the annular conductor 2 is substantially unnecessary, or an induction having a coil produced by winding a conventional coated copper wire a plurality of times. The cooling means can be made simpler than the heating device.

In addition, since the induced current flowing through the annular conductor 2 is very large, self-heating is increased, and the temperature of the annular conductor 2 is assumed to be extremely high, for example, 500 ° C. In such a case, the temperature of the portion surrounded by the magnetic body 4 shown in FIG. 4 (the power feeding portion 24) also becomes high, and this heat is transmitted to the coil 3 so that the heat resistance temperature of the copper wire covering material forming the coil 3 is reached. Is a problem. In order to avoid this, as shown in FIG. 5, the space between the annular conductor 2 and the coil 3 may be increased to increase the heat insulation capability of the portion surrounded by the magnetic body 4. Further, the electrical resistance of this portion may be reduced by increasing the cross-sectional area and surface area of the annular conductor 2 in this portion so that the temperature of the portion surrounded by the magnetic body 4 does not increase. Since the coil 3 is formed of a coated copper wire, the temperature of the coil 3 needs to be equal to or lower than the heat resistant temperature of the coating material, and it is desirable that the coil 3 is cooled by air blown from an air cooling fan (not shown).

Although not shown, if a magnetic body such as a ferrite core is disposed on the opposite side of the heating portion 25 of the annular conductor 2 of FIG. The resistance is reduced, and the efficiency of induction heating of the article 6 to be heated is further improved. This is a technique used also in a conventional induction heating apparatus using a coil formed by winding a coated copper wire a plurality of times, and such a known technique can also be used.

As shown in FIGS. 4 and 5, the magnetic body 4 does not necessarily have a form in which the annular conductor 2 and the coil 3 are completely closed and enclosed. FIG. 6 is a cross-sectional view when another form of magnetic material is used, and corresponds to the cross-sectional views of FIGS. 4 and 5. In FIG. 6, the cross-sectional shape of the magnetic body 4 is U-shaped, and a part of the magnetic circuit is not a magnetic body but a space (a nonmagnetic insulator such as air or a heat insulating material). In such a case, when a high-frequency current is passed through the coil 3, as shown in FIG. 6, a high-frequency magnetic flux φ1a linked to the annular conductor 2 and a high-frequency magnetic flux φ1b not linked to the annular conductor 2 are generated. Since a high-frequency induced current flows through the annular conductor 2 by the high-frequency magnetic flux φ1a interlinked with the body 2, the object to be heated 6 disposed in the vicinity of the annular conductor 2 can be induction-heated as described above. The high-frequency magnetic flux φ1b not interlinked with the annular conductor 2 is only stored as magnetic energy in the inductance of the coil 3, so that no energy loss occurs. In the case of the cross-sectional shape as shown in FIG. 5, the annular conductor 2 can be freely attached and detached from the magnetic circuit formed by the magnetic substance 4.

FIG. 7 is a cross-sectional view when another magnetic material is used. As shown in FIG. 7, even when a magnetic body 4a having an E-shaped cross section and a magnetic body 4b having an I-shaped cross section are used, the same as described above. In this case, as shown in FIG. 7, a space may be provided between the E-shaped magnetic body 4a and the I-shaped magnetic body 4b, or the E-shaped magnetic body 4a and the I-shaped without providing a space. Either of them may be in close contact with the magnetic body 4b. Thus, the form of the magnetic material is not limited to that described in the present embodiment, and the magnetic circuit is configured so that the high-frequency magnetic flux generated when a high-frequency current is passed through the coil 3 is linked to the annular conductor 2. I just need it.

FIG. 8 is a perspective view showing an induction heating apparatus 1 according to another coil form. FIG. 9 is a cross-sectional view taken along plane B in FIG. As shown in FIGS. 8 and 9, the coil 3 is formed by spirally winding a coated copper wire around a part of the magnetic body 4. Although not shown in the drawing, a heat insulating layer or an insulating material is appropriately provided between the coil 3 and the magnetic body 4 or between the coil 3 and the annular conductor 2 as in the induction heating apparatus 1 shown in FIG. is there. Further, unlike the annular conductor 2 in FIG. 1, the annular conductor 2 in FIG. 8 is not bent in an L shape, but may be bent in an L shape as in FIG. What can be done is the same as in the induction heating apparatus 1 of FIG.

Even when the induction heating apparatus 1 shown in FIG. 8 is supplied with a high frequency current of 20 to 100 kHz from the high frequency power source 5 to the coil 3, the high frequency magnetic flux φ1 is generated by the coil 3 as shown in FIG. The ring-shaped conductor 2 is linked through a magnetic circuit composed of the body 4. As a result, a high-frequency induced current flows through the annular conductor 2 by electromagnetic induction. Therefore, when an object to be heated (not shown) is arranged in the vicinity of the heating portion 25 of the annular conductor 2 as in the induction heating apparatus 1 of FIG. 1 described above, it is generated by a high-frequency induction current flowing through the annular conductor 2. The object to be heated is induction heated by the high frequency magnetic flux. As described above, the coil and the magnetic body are configured so that the high-frequency magnetic flux generated by the coil is linked to the annular conductor 2 even in other forms, not limited to the coil forms shown in FIGS. 1 and 8. For example, an object to be heated arranged in the vicinity of the heating portion 25 of the annular conductor 2 can be induction-heated.

FIG. 10 is a perspective view of an induction heating device in which the form of the annular conductor is different. In the induction heating apparatus 1 shown in FIG. 1 or 8 described above, the annular conductor 2 is formed in a single ring shape. For this reason, a large amount of the induced current flows inside the ring having a short path (that is, having a small electric resistance). As a result, the high-frequency magnetic flux generated by the induced current becomes strong inside the ring of the annular conductor 2, and the temperature distribution of the object to be heated arranged near the heating portion 25 of the annular conductor 2 may not be uniform.

Therefore, in the induction heating apparatus 1 shown in FIG. 10, the notch 7 is provided in the heating portion 25 of the annular conductor 2 to form two paths I1 and I2 through which induction current flows. The path I1 is inside the annular conductor 2, and the path I2 is outside the annular conductor 2. Further, the annular conductor 2 has a connecting portion 20c formed without providing a cut for connecting the path I1 and the path I2. The connecting portion 20c may not be provided, but the strength of the annular conductor 2 provided with the cuts 7 can be increased by forming the connecting portion 20c.

In FIG. 10, the induced current flowing through the path I1 is denoted by Ia, and the induced current flowing through the path I2 is denoted by Ib. The width of the path I1 is narrower than the width of the path I2. That is, the electric resistance per unit length is smaller in the path I2 than in the path I1. As a result, the induced current is prevented from concentrating and flowing in the short path I1 inside the annular conductor 2, and the induced current also flows in the path I2. The ratio of the magnitudes of the induced current Ia flowing in the path I1 and the induced current Ib flowing in the path I2 is not necessarily equal, and the induced current Ia can be changed by arbitrarily changing the shape of the cut 7 and the width of the paths I1 and I2. Or the induced current Ib may be increased.

Also, the number of paths through which the induced current flows is not limited to two, and may be three or more. That is, an arbitrary notch 7 can be formed according to the purpose of use, and an arbitrary path can be formed. Whether or not a desired temperature distribution can be obtained thereby can be obtained easily by preparing a material with various conditions and measuring the temperature distribution.

Embodiment 2. FIG.
In this embodiment, a heating system using the induction heating device described in Embodiment 1 will be described. The form of the induction heating apparatus described in this embodiment is an example, and all the induction heating apparatuses described in Embodiment 1 can be used as appropriate instead of the form described here.

The heating system described in this embodiment uses the induction heating apparatus described in Embodiment 1 for a microwave oven or microwave oven. 11 is a front view showing the heating system of the second embodiment in perspective, and FIG. 12 is a cross-sectional view of the heating system of FIG. 11 as seen from the front. In FIG. 11, a part of the components shown in FIG. 12 is omitted. The heating system 8 includes a heating chamber 10 inside a housing 9 made of a metal such as iron, stainless steel, or aluminum, or an insulating member such as ceramics or heat resistant resin. The heating chamber 10 has a box-like shape opened to the front surface of the housing 9, and is formed of a metal such as iron, stainless steel, and aluminum, the right side wall 11, the left side wall 12, the rear wall 13, the ceiling wall 14, and heat resistant glass. And a bottom wall 15 formed of a heat-resistant nonmagnetic insulator such as ceramics. A door (not shown) that can be opened and closed is disposed on the front surface of the heating chamber 10. The door has the same structure as a conventionally known microwave oven door, and has a glass window in which a metal mesh is formed so that microwaves do not leak into a metal frame.

As shown in the figure, the induction heating device 1 is disposed inside the heating system 8. On the lower side of the bottom wall 15 (outside of the heating chamber 10), a heating unit 25 (a portion for induction heating of the object to be heated 6) of the annular conductor 2 of the induction heating device 1 is provided in the vicinity of the bottom wall 15. The induction heating device 1 is arranged inside the heating system 8 so that the coil 3 and the magnetic body 4 of the induction heating device 1 and the feeding part 24 of the annular conductor 2 are arranged outside the right side wall 11 of the heating chamber 10. Is arranged. In addition, the coil 3 and the magnetic body 4 of the induction heating device 1 and the power feeding unit 24 of the annular conductor 2 are not limited to be disposed outside the right side wall 11 of the heating chamber 10, but the left side wall 12, the rear wall 13, Alternatively, it may be arranged outside the ceiling wall 14. That is, what is necessary is just to be arrange | positioned on the outer side of the metal wall of the heating chamber 10. FIG.

The right side wall 11 of the heating chamber 10 is provided with a hole 16 for ensuring electrical insulation from the annular conductor 2. The holes 16 may be formed by cutting or the like in one metal plate (right side wall 11), but may be formed by butting two metal plates together. Although the annular conductor 2 and the right side wall 11 are insulated by the hole 16, the insulation distance may be very small (for example, 1 mm or less), and the leakage of the microwave from the heating chamber 10 can be suppressed.

Furthermore, a high frequency power source 5 is disposed inside the heating system 8, and both ends of the coil 3 of the induction heating device 1 are connected to the high frequency power source 5. Then, one place of the annular conductor 2, the right side wall 11, and the GND potential (reference potential) of the high-frequency power source 5 are electrically connected. The annular conductor 2 and the right side wall 11 may be connected by wiring by a conductive wire, but the induction heating device 1 is arranged inside the heating system 8 so that a part of the annular conductor 2 and the right side wall 11 are close to each other, You may connect by mechanical means, such as screwing. The right side wall 11 of the heating chamber 10 is electrically connected by integrally molding with the left side wall 12, the rear wall 13, and the ceiling wall 14 or by joining each piece by mechanical means such as screwing after each wall is separately manufactured. The

Thus, even if the annular conductor 2 is irradiated with microwaves by electrically connecting the annular conductor 2, the right side wall 11 of the heating chamber 10, and the high-frequency power source 5, the wall of the heating chamber 10 or the coil 3. Spark discharge can be prevented from occurring between the two. The annular conductor 2 is a one-turn closed circuit made of a highly conductive metal, and is not formed by winding a coated copper wire a plurality of times like a coil of a conventional induction heating device. When this is done, high voltage is not generated between the coil wires, and the spark wire does not break the copper wire coating. Therefore, special means for protecting the induction heating coil from microwaves is not required unlike a microwave oven having a conventional induction heating coil.

Furthermore, a magnetron 17a for generating microwaves is provided inside the heating system 8, and a micro discharge hole 17b for releasing microwaves is provided in a part of the right side wall 11 of the heating chamber 10. . The magnetron 17a and the microwave emission hole 17b are connected via a waveguide 17c. The microwave emission hole 17b may be closed with an insulator (not shown).

On the upper surface of the bottom wall 15, an oven dish 6 (object to be heated) formed of a magnetic metal such as iron or magnetic stainless steel is disposed, and a food material 60 such as a hamburger is placed on the oven dish 6. Further, a magnetic shield 18 made of a high conductivity metal such as copper or aluminum is provided on the back side of the heating portion 25 of the annular conductor 2 (the surface opposite to the heating portion 25) with a predetermined distance from the annular conductor 2. Is provided.

The magnetic shield 18 prevents the bottom wall 15 of the heating chamber 10 from being inductively heated by the high frequency magnetic flux generated when an induction current flows through the annular conductor 2. When an induced current flows through the annular conductor 2 to generate a high-frequency magnetic flux φ2 and the high-frequency magnetic flux φ2 reaches the magnetic shielding plate 18, the induced current is generated in the magnetic-shielding plate 18 so as to generate a high-frequency magnetic flux φ3 in a direction that interferes with the high-frequency magnetic flux φ2. Flows. Then, by canceling out the high frequency magnetic fluxes φ2 and φ3, the lower surface of the casing 9 outside the magnetic shield 18 is prevented from being induction heated. However, the high-frequency magnetic flux φ3 functions to cancel the high-frequency magnetic flux φ2 even in the induction heating of the oven dish 6 that is the object to be heated.

Therefore, when the distance between the annular conductor 2 and the magnetic shield 18 is short, the efficiency of induction heating of the object to be heated also decreases. According to experiments, the distance between the annular conductor 2 and the magnetic shield 18 is desirably 10 mm or more, and 20 mm or more is sufficient. However, even if it is 10 mm or less (even if it is close to 1 mm), the efficiency of induction heating is reduced, but it can be used as an induction heating device. When the efficiency of induction heating decreases, the power consumption in the annular conductor 2 increases and the temperature of the annular conductor 2 rises. However, as described in Embodiment 1, the heat generation of the annular conductor 2 is also caused by the heating object. Useful for heating. If a magnetic material such as a ferrite core is disposed between the annular conductor 2 and the magnetic shield 18, the distance between the annular conductor 2 and the magnetic shield 18 can be further reduced.

FIG. 13 shows a cross-sectional view when a magnetic body such as a ferrite core is provided between the annular conductor 2 and the magnetic shield 18, and shows a portion corresponding to the II cross section of FIG. Since the magnetic body 19 such as a ferrite core absorbs microwaves, there is a problem that when it is irradiated with microwaves, the magnetic body 19 becomes high in temperature and breaks or the saturation magnetic flux density or permeability decreases. Therefore, as shown in FIG. 13, the width of the magnetic body 19 is made narrower than the width of the ring-shaped conductor 2, that is, the magnetic body 19 is hidden by the ring-shaped conductor 2 from the microwave. The magnetic body 19 can be arranged between them, and the space | interval of the annular conductor 2 and the magnetic-shield board 18 can be narrowed.

Returning to FIGS. 11 and 12, the general microwave oven and microwave oven components such as the drive circuit of the magnetron 17a (not shown) and the control circuit of the heating system 8 are provided, and the whole is made of metal such as iron or stainless steel. A heating system 8 is configured by being surrounded by a housing 9. Further, as in a known microwave oven, a flat heater is provided on the back side of the ceiling wall 14 of the heating chamber 10, or an electric resistance heater such as a radiant heater or a sheathed heater is provided above the inside of the heating chamber 10. You can also.

Next, the operation will be described. For example, after the user places an uncooked hamburger or other food 60 on the oven dish 6 (object to be heated) and installs it inside the heating system 8, the cooking selection provided on the front surface of the heating system 8 (not shown) When hamburger cooking is selected from the menu, a high frequency current is supplied from the high frequency power source 5 to the coil 3. Then, a high frequency high current is induced in the annular conductor 2 and the oven dish 6 is induction heated. Then, the temperature of the oven dish 6 rises and the surface of the food 60 is baked. In addition, when an electric resistance heater is installed above the heating chamber 10, the food 60 may also be heated from above by supplying power to the electric resistance heater.

Then, when a predetermined time has elapsed and the surface of the food 60 becomes colored, the magnetron 17a is operated, and the food 60 is irradiated with the microwave from the microwave discharge hole 17b. As a result, the surface of the food 60 is heated only by induction heating or a combination of induction heating and an electric resistance heater, and the inside is heated by microwaves, so that cooking can be completed in a short time. Note that induction heating and microwave heating may be performed simultaneously or in a time-sharing manner.

As described above, cooking can be performed by combining induction heating optimal for the surface heating of the food 60 and microwave heating optimal for the internal heating of the food 60, so that the cooking time can be shortened, and the user uses a plurality of cookers properly. There is an advantage that there is no complication. In addition, the usage method of the heating system 8 of this Embodiment is not restricted to this, Induction heating and microwave heating may be used separately or simultaneously, and the usage method is arbitrary. In the present embodiment, the entire bottom wall 15 is formed of a heat-resistant nonmagnetic insulator such as heat-resistant glass or ceramics. However, the present invention is not limited to this, and a part of the bottom wall 15 is heat-resistant nonmagnetic insulation. What is necessary is just to be formed with the thing.

Embodiment 3 FIG.
In this embodiment, a heating system using the induction heating device described in Embodiment 1 will be described as in Embodiment 2. The form of the induction heating apparatus described in this embodiment is an example, and all the induction heating apparatuses described in Embodiment 1 can be used as appropriate instead of the form described here.

FIG. 14 is a perspective view showing the heating system of the present embodiment in perspective, and FIG. 15 is a sectional view seen from the front. In FIG. 14, some of the components shown in FIG. 15 are omitted. The heating system 8 has a heating chamber 10 inside a housing 9 made of metal such as iron, stainless steel, and aluminum. The housing 9 is not necessarily made of metal, but may be an insulator such as a heat-resistant resin depending on ceramics or use temperature, but is preferably made of metal from the viewpoint of cost and strength.

The heating chamber 10 is formed in a substantially rectangular parallelepiped shape by a right side wall 11, a left side wall 12, a rear wall 13, a ceiling wall 14, a bottom wall 15 and an openable / closable door (not shown). The right side wall 11, the left side wall 12, and the rear wall 13 are formed of a metal plate such as iron, stainless steel, and aluminum. As shown in FIG. 15, two metal plates are stacked with a predetermined space. Formed by. The space between the two metal plates serves as a heat insulating layer and suppresses the heat inside the heating chamber 10 from flowing out of the heating chamber 10. In addition, a heat insulating material such as glass wool or ceramic wool may be provided between two metal plates to further enhance the heat insulating property, and the right side wall 11, the left side wall 12, and the rear wall 13 are formed by one metal plate, You may provide a heat insulating material in the outer side (outside of the heating chamber 10). The right side wall 11, the left side wall 12, and the rear wall 13 may be formed of a heat resistant insulator such as heat resistant glass or ceramics. Further, the door (not shown) may be formed of a metal or a heat-resistant insulator, and may have a window formed of heat-resistant glass so that the inside can be observed. The ceiling wall 14 and the bottom wall 15 are made of a conductive metal material such as a magnetic metal plate such as iron or magnetic stainless steel, or a high volume resistivity such as nonmagnetic stainless steel or carbon plate.

14 and 15, the induction heating device 1 is disposed outside the heating chamber 10 and inside the housing 9. On the upper side of the ceiling wall 14 (outside of the heating chamber 10) and the lower side of the bottom wall 15 (outside of the heating chamber 10), the heating section 25 of the annular conductor 2 of the induction heating device 1 is arranged. The part (feeding part 24) which has the coil 3 and the magnetic body 4 of the induction heating apparatus 1 is arrange | positioned at the right side of the right side wall 11 (outside of the heating chamber 10).

In addition, the part (electric power feeding part 24) which has the coil 3 and the magnetic body 4 of the induction heating apparatus 1 may be arrange | positioned at a part of the ceiling wall 14, the part of the bottom wall 15, or the left side of the left side wall 12. Alternatively, it may be disposed further rearward of the rear wall 13. A high frequency power supply 5 is also disposed inside the housing 9. 14 and 15, the heating portion 25 of the annular conductor 2 of the induction heating device 1 faces both the ceiling wall 14 and the bottom wall 15 (that is, both the ceiling wall 14 and the bottom wall 15 are induction-heated). However, only one of the ceiling wall 14 and the bottom wall 15 may be heated by induction heating. Further, the structure of any of the right side wall 11, the left side wall 12, and the rear wall 13 is made the structure of the ceiling wall 14 or the bottom wall 15, and the heating portion 25 of the annular conductor 2 is disposed so as to face the wall surface, Any one of the right side wall 11, the left side wall 12, and the rear wall 13 may be induction heated.

Further, even when both the ceiling wall 14 and the bottom wall 15 are induction-heated, the induction heating apparatus 1 arranged to induction-heat only the ceiling wall 14 and the induction arranged to induction-heat only the bottom wall 15. Two induction heating devices of the heating device 1 may be arranged inside the housing 9 and the ceiling wall 14 and the bottom wall 15 may be individually induction heated. Further, for example, the heating portion 25 of the annular conductor 2 is formed in a shape facing the two walls so that two walls orthogonal to each other such as the ceiling wall 14 and the rear wall 13 are inductively heated, and the two walls May be induction heated at the same time.

The ceiling wall 14 and the bottom wall 15 and the heating part 25 of the annular conductor 2 are arranged close to each other. As described in the first embodiment, the ceiling wall 14 and the bottom wall 15 that are heated objects and the annular conductor 2 need to be electrically insulated. A heat-resistant insulating sheet is disposed between the bodies 2 to insulate, or an insulating film is formed on both surfaces of the ceiling wall 14 and the bottom wall 15 and the annular conductor 2 by insulating coating or oxide film formation. It is formed and insulated.

Although the annular conductor 2 does not need to be cooled as described in the first embodiment, the ceiling wall 14 and the bottom wall 15 are prevented from flowing out through the annular conductor 2 to the outside. 14 and a bottom wall 15 and a heating part 25 of the annular conductor 2 may be provided with a heat insulating material such as glass wool or ceramic wool.

It faces the bottom wall 15 on the upper side (opposite side of the heating unit 25) of the annular conductor 2 arranged on the upper side of the ceiling wall 14 and facing the ceiling wall 14, and on the lower side of the bottom wall 15. A high conductivity such as copper or aluminum is provided at a predetermined distance from the heating part 25 of the annular conductor 2 on the lower side (opposite to the heating part 25) of the heating part 25 of the annular conductor 2 arranged A magnetic shielding plate 18 made of a metal plate with a constant rate is arranged. The reason why the magnetic shield 18 is arranged is as described in the second embodiment, and the magnetic shield 18 operates as described in the second embodiment.

The space provided between the annular conductor 2 and the magnetic shield 18 also serves as a heat insulating layer, and suppresses the heat of the heating chamber 10 from flowing out of the casing 9 of the heating system 8. Therefore, air (simple space) may be provided between the annular conductor 2 and the magnetic shield 18, but a heat insulating material such as glass wool or ceramic wool may be interposed.

Further, a magnetic body such as a ferrite core is disposed on the side opposite to the side facing the ceiling wall 14 and the bottom wall 15 of the heating part 25 of the annular conductor 2 (between the heating part 25 of the annular conductor 2 and the magnetic shield 18). However, the efficiency of induction heating may be improved by increasing the magnetic flux density for induction heating the ceiling wall 14 and the bottom wall 15. This is also as described in the second embodiment, but in this embodiment, since the magnetic material is not irradiated with microwaves, the arrangement is such that the magnetic material is hidden by the annular conductor 2 as described in the second embodiment. It does not have to be. That is, the arrangement method of the magnetic body is arbitrary. When the temperature of a magnetic material such as a ferrite core increases, the saturation magnetic flux density decreases, and when the temperature exceeds the Curie point, the magnetic permeability decreases rapidly. Depending on the operating temperature, the heating unit 25 of the annular conductor 2 and the magnetic material It is good to interpose heat insulating materials, such as glass wool and ceramic wool, between. Iron cores and dust cores can provide a sufficiently higher saturation magnetic flux density than a ferrite core and have a sufficiently high Curie point even in a high temperature environment of about 200 ° C. Therefore, an iron core or dust core may be used instead of a ferrite core. . In this case, since the temperature may be higher than when a ferrite core is used, the heat insulating structure between the annular conductor 2 and the magnetic body can be simplified.

Next, the operation will be described. As shown in FIG. 15, an object to be heated such as a food 60 is put into the heating system 8 from a door (not shown). Note that the object to be heated is not limited to food, but may be any industrial product that is subjected to heat treatment, for example. The article to be heated may be placed directly on the bottom wall 15 or may be placed on the grill net 51 as shown in FIG. When a high-frequency current is supplied from the high-frequency power source 5 to the coil 3 after the object to be heated (foodstuff 60) is placed inside the heating chamber 10 of the heating system 8 and the door (not shown) is closed, the first embodiment will be described. As described above, a high-frequency large current is induced in the annular conductor 2. When a high-frequency high current flows through the annular conductor 2, a high-frequency magnetic flux is generated around the annular conductor 2 as described in the first embodiment, and the annular conductor 2 is disposed facing the heating unit 25. The ceiling wall 14 and the bottom wall 15 of the heating chamber 10 generate heat by induction heating. When the ceiling wall 14 and the bottom wall 15 generate heat, the air in the heating chamber 10 is heated to a high temperature by convection heat transfer, and an object to be heated such as the food 60 installed in the heating chamber 10 is convectively transferred from the high-temperature air. Heated by heat. That is, the heating system 8 operates as an oven.

Since the heating system 8 operates as an oven, the air temperature inside the heating chamber 10 may reach 200 to 300 ° C. (for example, when used as a drying furnace, it may not be such a high temperature, so “may be”). ) In that case, the ceiling wall 14 and the bottom wall 15 are hotter than the air temperature inside the heating chamber 10, but the induction heating device 1 of the present invention uses the annular conductor for induction heating as described in the first embodiment. 2, the heating part 25 of the annular conductor 2 is arranged close to the ceiling wall 14 and the bottom wall 15 even when the ceiling wall 14 and the bottom wall 15 are at a high temperature of 200 to 300 ° C. or higher. Therefore, the efficiency of induction heating can be increased, and no cooling means is required. In addition, since the part (feeding part 24) which has arrange | positioned the coil 3 and the magnetic body 4 of the induction heating apparatus 1 needs to be below the heat-resistant temperature of the coating material of coil copper wire, this part is cooled by a ventilation cooling means etc. The Further, even if the heating part 25 of the annular conductor 2 generates heat due to its own electrical resistance and Joule heat due to the induced current flowing through this part, this heat is used for heating the heating chamber 10 as described in the first embodiment. Therefore, the heating efficiency of the heating system 8 can be increased.

Note that it is also possible to obtain a heating system using microwave heating in combination with a magnetron as described in Embodiment 2 in the heating system 8 of FIGS. In this case, the magnetic material disposed in the annular conductor 2 or the heating portion 25 of the annular conductor 2 is shielded from microwave irradiation by the ceiling wall 14 and the bottom wall 15, and thus as described in the second embodiment. No treatment for electrically connecting the annular conductor 2 and the wall surface of the heating chamber 10 is necessary.

FIG. 16 is a cross-sectional view of another heating system in which the material of the ceiling wall 14 and the bottom wall 15 of the heating system 8 shown in FIG. 15 is different from the front. In the heating system 8 shown in FIG. 16, the ceiling wall 14 and the bottom wall 15 are formed of a heat-resistant nonmagnetic insulator such as heat-resistant glass or ceramics. That is, components used for microwave irradiation such as magnetron are deleted from the heating system shown in the second embodiment. Note that part of the ceiling wall 14 and the bottom wall 15 may be formed of a heat-resistant nonmagnetic insulator such as heat-resistant glass or ceramics. The heating system 8 of FIG. 16 can induction-heat the to-be-heated object installed in the inside of the heating chamber 10 from above and below. The oven container 26 to be heated is in the form of a box formed of a magnetic metal such as iron or magnetic stainless steel, and the container portion 26a and the container portion 26 that contain the food 60 (object to be heated) are contained therein. And a removable lid portion 26b. When the food container 60 or the like is put in the container portion 26a, the oven container 26 covered with the lid portion 26b is installed inside the heating chamber 10, and the high frequency current is supplied from the high frequency power source 5 to the coil 3 of the induction heating device 1, Thus, the container part 26a and the cover part 26b are induction-heated. As a result, the oven container 26 becomes hot and the internal food 60 is cooked by heating. The object to be heated is not limited to the one that is heat-treated inside the oven container 26 like the oven container 26 described here, for example, a removable inner lid that partitions the inside of the oven container 26 in the vertical direction, It is possible to inductively heat separate objects to be heated in the upper space and the lower space in the oven container 26, and the usage method is arbitrary.

Thus, the application of the heating system can be easily changed depending on whether the ceiling wall 14 and the bottom wall 15 are formed of a magnetic metal material or an insulator. For example, when the two types of heating systems 8 described in this embodiment are prepared in the product lineup, two types of products can be easily realized by preparing only two types of materials for the ceiling wall 14 and the bottom wall 15. it can. Further, if the ceiling wall 14 and the bottom wall 15 are detachable so that the magnetic metal plate and the insulating plate can be exchanged, the user can use two types of heating systems properly according to the application.

Embodiment 4 FIG.
In this embodiment, a heating system using the induction heating apparatus described in Embodiment 1 will be described as in Embodiments 2 and 3. The form of the induction heating apparatus described in this embodiment is an example, and all the induction heating apparatuses described in Embodiment 1 can be used as appropriate instead of the form described here.

FIG. 17 is a partially exploded perspective view showing the heating system of the fourth embodiment, and FIG. 18 is a sectional view of the heating system. The heating system 8 described in the present embodiment uses the induction heating device of the present invention instead of the induction heating coil of a known heating system as a so-called IH cooking heater. Therefore, the induction heating apparatus of the present invention can be used in place of the induction heating coil even if the IH cooking heater is not limited to the embodiment described in the third embodiment.

17 and 18, the heating system 8 has a box-shaped housing (heating system main body) 31. The upper surface of the housing 31 is covered with a top plate 32 on which an object to be heated such as a pan or a frying pan is placed. The top plate 32 is formed of a heat resistant insulator such as heat resistant glass, ceramics, or heat resistant resin. In FIG. 17, the casing 31 and the top plate 32 are shown separately. However, in actuality, as shown in FIG. 18, the top plate 32 is arranged on the casing 31 and fixed integrally. . The casing 31 may be a metal material such as iron, stainless steel, or aluminum, or may be an insulating material such as ceramic or resin, and may be selected according to the intended use.

As shown in the drawing, the induction heating device of the present invention is disposed inside the casing 31. In this embodiment, the case where two induction heating devices of the present invention are arranged will be described, but it may be one or three or more. Moreover, you may use together with the induction heating coil formed by winding the conventional coated copper wire several times. The induction heating devices 1 a and 1 b are arranged so that the heating portions 25 a and 25 b of the respective annular conductors 2 a and 2 b are arranged on the left and right sides of the heating system 8 and are close to or in close contact with the back side of the top plate 32.

Magnetic materials 34a and 34b such as ferrite cores may be disposed on the back side of the heating portions 25a and 25b of the annular conductors 2a and 2b. Since the high-frequency magnetic flux generated when the induced current flows through the annular conductors 2a and 2b is in a direction perpendicular to the path through which the induced current flows as shown in FIG. It is preferable that the longitudinal direction of the rod-shaped magnetic body be aligned with the path of the induced current of the conductors 2a and 2b. The magnetic bodies 34a and 34b are not always necessary, and the efficiency of induction heating of the pan 36a and the frying pan 36b, which are heated objects, is improved by arranging the magnetic bodies 34a and 34b on the back side of the annular conductors 2a and 2b. . Further, although not shown in the drawings, as shown in the second and third embodiments, copper or aluminum or the like is placed on the back side of the annular conductors 2a and 2b (lower than the magnetic material if there is a magnetic material). You may arrange | position the magnetic-shield board which consists of a metal plate of electrical conductivity.

In FIG. 17, the coils 3 a and 3 b and the magnetic bodies 4 a and 4 b ( power feeding parts 24 a and 24 b) of the induction heating devices 1 a and 1 b are arranged in the center part of the heating system 8, but are not limited to this and are arbitrary. Moreover, the coil 3a of the induction heating apparatus 1a is connected to the high frequency power source 5a. On the other hand, the coil 3b of the induction heating device 1b is connected to a high frequency power source 5b, and a high frequency current is supplied from the high frequency power sources 5a and 5b to the coils 3a and 3b. Although not shown, an air cooling fan is provided inside the heating system 8, and the coils 3a and 3b and the high frequency power supplies 5a and 5b are blown to cool them.

Next, the operation will be described. When a high frequency current of 20 to 100 kHz is supplied from the high frequency power sources 5a and 5b to the coils 3a and 3b of the induction heating devices 1a and 1b, the induction current flows through the annular conductors 2a and 2b as described in the first embodiment. The pot 36a and the frying pan 36b, which are objects to be heated, placed on the top plate 32 are induction-heated. When the induced current flows through the annular conductors 2a and 2b, the annular conductors 2a and 2b themselves generate heat due to Joule heat. However, as described in the first embodiment, the heating portions 25a and 25b of the annular conductors 2a and 2b Since there is no need for cooling, the heat generated by the annular conductors 2a and 2b is also useful for heating the pan 33a and the frying pan 33b, which are heated objects, and the heated objects can be induction-heated efficiently. Further, since a member for cooling the heating portions 25a and 25b of the annular conductors 2a and 2b is not required, a space is effectively provided such as arranging a circuit under the annular conductors 2a and 2b. The heating system 8 can be made small.

Furthermore, since no gap is required for flowing an air flow above the annular conductors 2a and 2b, the annular conductors 2a and 2b are brought close to the top plate 32 to reduce the distance from the object to be heated. Heating efficiency can be increased. The heating system using the induction heating device described in the first embodiment is not limited to the heating systems in the second to fourth embodiments. The induction heating device of the present invention can be used in place of the coil of almost all induction heating devices using a coil formed by winding a conventional conductive wire a plurality of times.

Embodiment 5 FIG.
In this embodiment, a heating system using the induction heating device described in Embodiment 1 will be described as in Embodiments 2, 3, and 4. The form of the induction heating apparatus described in this embodiment is an example, and all the induction heating apparatuses described in Embodiment 1 can be used as appropriate instead of the form described here.

FIG. 19 is a front view showing the heating system of the fifth embodiment, which is shown in perspective. 20 is a cross-sectional view of the heating system 8 as viewed from the front, and FIG. 21 is a cross-sectional view of the heating system 8 as viewed from the side. The heating system 8 has a heating chamber 10 inside a housing 9 made of a metal such as iron, stainless steel, aluminum, or an insulating portion such as ceramics or heat-resistant resin. The heating chamber 10 has a box shape opened to the front surface of the housing 9, and includes a right side wall 11, a left side wall 12, a rear wall 13, a ceiling wall 14, and a bottom wall 15.

The right side wall 11, the left side wall 12, and the bottom wall 15 of the heating chamber 10 are made of a metal such as iron or stainless steel or an insulator such as ceramics or heat resistant glass. The right side wall 11, the left side wall 12, and the bottom wall 15 have a heat insulating structure, and the heat in the heating chamber 10 is suppressed from being released to the outside of the heating chamber 10. Specifically, for example, these walls may be formed of two metal plates, a space may be formed between the two metal plates, and this may be used as a heat insulating layer, or heat insulation such as glass wool or ceramic wool may be formed in this space. It is good also as a heat insulation layer by putting material. Moreover, even when it forms with one metal plate, it is good also as a heat insulation structure by providing heat insulating materials, such as glass wool and ceramic wool, on the outer side. The same applies to the case where these walls are formed of an insulator such as glass or ceramics.

The rear wall 13 of the heating chamber 10 is formed of a nonmagnetic insulator such as ceramics or heat resistant glass. As shown in FIG. 21, the rear wall 13 bends the central portion of the lower portion of the heating chamber 10 outward to form a groove portion 42 having a U-shaped cross section extending in the horizontal direction in the heating chamber 10. A part of the heater 45 made of a conductor that forms an electrical closed circuit is inserted into the groove 42.

The heater 45 is formed into a one-turn endless shape by bending a metal rod or a metal pipe such as stainless steel or high nickel alloy into a predetermined shape and joining both ends together by welding or brazing. And the shelf part 46a, 46b is formed in the right side wall 11 and the left side wall 12 of the heating chamber 10, and the heater 45 has the groove part 42 and the shelf part 46a formed in the lower stage position of the right and left both side walls 11, 12. It is supported by 46b and installed inside the heating chamber 10. Therefore, the heater 45 is only supported by the groove 42 and the shelves 46a and 46b, and has no electrical contact, and is detachable from the heating chamber 10. Therefore, the user can remove the heater 45 after cooking and easily clean the inside of the heating chamber 10. Moreover, it can also replace | exchange for the heater of a different shape according to the objective of cooking.

The ceiling wall 14 of the heating chamber 10 is formed of a plate made of a magnetic metal such as iron or magnetic stainless steel, or a carbon material such as nonmagnetic stainless steel or a graphite plate. When the ceiling wall 14 is formed of a plate made of a carbon material, the carbon material is heated by induction heating, and the food can be cooked by radiation from the carbon material, so that the effect of charcoal grilling is obtained. A part of the ceiling wall 14 may be formed of a magnetic metal such as iron or magnetic stainless steel, or a plate made of a carbon material such as nonmagnetic stainless steel or a graphite plate.

The heating unit 25 of the annular conductor 2 of the induction heating device of the present invention is arranged on the upper side of the ceiling wall 14. As described in the first embodiment, the annular conductor 2 and the ceiling wall 14 are electrically insulated by an insulator or an insulating film. For example, mica has a high heat-resistant temperature and can be thin and strong, so a mica plate or a mica sheet may be used as an insulator between the annular conductor 2 and the ceiling wall 14. When the ceiling wall 14 is heated to a high temperature (for example, 600 ° C. or more) by induction heating, a heat insulating material such as ceramic wool is provided between the annular conductor 2 and the ceiling wall 14 so that the heat of the ceiling wall 14 is the annular conductor. 2 may be prevented from flowing out to the outside. When the ceiling wall 14 is heated to, for example, 700 ° C. or higher, the annular conductor 2 is made of copper because the annular conductor 2 is softened when it is aluminum. When the annular conductor 2 is formed of copper, an oxide film (copper oxide) is formed on the surface of the annular conductor 2 in advance by a chemical method such as high temperature heating or anodization, or the surface of the annular conductor 2 is nickel-plated. It is preferable to prevent rust (copper oxide) from being generated on the copper surface even if the annular conductor 2 is exposed to a high temperature environment.

A magnetic shield 18 made of a high conductivity metal such as copper or aluminum is provided above the annular conductor 2 with a predetermined space therebetween. A space between the annular conductor 2 and the magnetic shield 18 functions as a heat insulating layer, and this space may be air, but a heat insulating material such as glass wool or ceramic wool may be provided. Further, when a magnetic body such as a ferrite core is disposed above the heating portion 25 of the annular conductor 2, a heat insulating material such as ceramic wool may be provided between the annular conductor 2 and the magnetic body. Further, a heat-resistant plate made of a heat-resistant insulator may be provided between the annular conductor 2 and the magnetic shield plate 18 to block air between the annular conductor 2 and the heat-resistant plate and air between the heat-resistant plate and the magnetic shield plate 18. . In this case, when a magnetic body such as a ferrite core is disposed, the magnetic body may be disposed between the heat-resistant plate and the magnetic shield plate 18. Further, an air flow may be passed between the heat-resistant plate and the magnetic shielding plate 18 to suppress the air between the heat-resistant plate and the magnetic shielding plate 18 from becoming a high temperature. A magnetic body such as a ferrite core may not function sufficiently due to a decrease in saturation magnetic flux density when placed in a high temperature environment. However, since the temperature of the environment in which the magnetic material is disposed can be lowered by flowing an air flow between the heat-resistant plate and the magnetic shielding plate 18, the ceiling wall 14 can be efficiently induction-heated by the annular conductor 2. As such a heat-resistant plate, a ceramic plate or a mica plate can be used.

And the electric power feeding part 24 of the cyclic | annular conductor 2 is linked with the magnetic body 4a of the induction heating apparatus 1 provided in the back side of the rear wall 13 of the heating chamber 10. FIG. In FIG. 21, the cross section of the feeding part 24 of the annular conductor 2 is indicated by a circle. However, the heating part 25 of the annular conductor 2 is formed of a metal plate, the feeding part 24 is formed of a round bar, and both are welded. It means that it is joined by brazing. In this way, by forming the feeding portion 24 of the annular conductor 2 with a round bar, the electrical resistance is reduced, and the feeding portion 24 generates heat due to Joule heat due to the induced current flowing through the annular conductor 2 and becomes high temperature. It is preventing. A round pipe may be used in place of the round bar. When the pipe is made of copper, if the round pipe has a wall thickness of 0.74 mm or more, the electrical resistance can be made smaller than that of the round bar at 20 to 100 kHz due to the skin effect. As a matter of course, other cross-sectional shapes such as a square bar and a square pipe may be used instead of the round bar and the round pipe. Further, as shown in the first embodiment, a single metal plate may be processed to integrally form the heating part 25 and the power feeding part 24 of the annular conductor 2.

FIG. 22 is a perspective view showing the structure of the coil 3, the magnetic body 4a, and the magnetic body 4b of the induction heating apparatus 1. FIG. The magnetic body 4 b is used for heating the heater 45. The coil 3 is manufactured by winding a so-called litz wire made of a plurality of (for example, 38) stranded wires of a coated copper wire having a diameter of about 0.3 mm in a flat shape a plurality of times (for example, 15 times). Then, the magnetic bodies 4a and 4b are provided so as to surround the wire bundle in the same direction of the coil 3 (part of the coil bundle and another coil bundle). In FIG. 22, the magnetic body 4a is shown in a square shape (square cylindrical shape), but it may be U-shaped like the magnetic body 4b. The magnetic body 4a may be U-shaped as shown in FIG. 6 of the first embodiment. As shown in FIG. 21, a heat insulating material 52 a is provided between the magnetic body 4 a and the power feeding portion 24 of the annular conductor 2.

On the other hand, a heat insulating material 52b such as glass wool or ceramic wool is provided on the outer side of the U-shaped cross section in which the groove portion 42 of the rear wall 13 is formed, and a magnetic body made of a ferrite core having a U-shaped cross section on the outer side. 4b is provided. And the coil 3 is provided between the magnetic body 44b and the heat insulating material 52b. Note that the heat insulating materials 52a and 52b are not necessarily required, and heat insulation between the feeding portion 24 of the annular conductor 2 and the coil 3 may be secured by an air layer or an air flow instead of the heat insulating materials 52a and 52b.

And the magnetic-shielding cover 55 which consists of metal plates with high conductivity, such as aluminum and copper, is provided outside the induction heating device 1 so as to surround the coil 3 of the induction heating device 1. The magnetic shielding cover 55 is provided for the purpose of suppressing wasteful power consumption due to the induction of the magnetic flux leaking from the coil 3 to the casing 9 of the heating system 8. Specifically, when the leakage magnetic flux from the coil 3 reaches the magnetic shielding cover 55, an induction current flows in the magnetic shielding cover 55 in a direction to cancel the leakage magnetic flux by electromagnetic induction, and the magnetic flux leaking outward from the magnetic shielding cover 55 can be offset. Since the magnetic shielding cover 55 is made of a metal having high conductivity, the electric power consumed as Joule heat by the induced current generated by the leakage magnetic flux is small, and the leakage magnetic flux reaches the housing 9 to inductively heat the housing 9. Unnecessary power consumption can be suppressed compared to the power consumption. The magnetic shield cover 55 also serves as a wind tunnel for cooling the coil 3, and the coil 3 is cooled by the air blow from the air cooling fan 56 provided on the magnetic shield cover 55.

A door 53 that can be opened and closed made of a heat-resistant material such as heat-resistant glass or metal is provided in front of the heating chamber 10 of the heating system 8. The door 53 is fixed to a slide rail 54 provided inside or outside the heating chamber 10, and the food 60 can be taken in and out of the heating chamber 10 by being guided by the slide rail 54 and opened and closed. . In addition, a fat pan 50 and a grill 51 that move back and forth as the door 53 opens and closes are disposed inside the heating chamber 10.

Next, the operation will be described. When a high frequency current of 20 to 100 kHz is supplied from the high frequency power source 5 to the coil 3, the high frequency current flows through the annular conductor 2 as described in the first embodiment, and faces the heating unit 25 of the annular conductor 2. The ceiling wall 14 arranged in this manner is induction-heated. Similarly, since the high frequency magnetic flux generated by the coil 3 also passes through the magnetic body 4 b and is linked to the heater 45 in the heater 45, a high frequency induction current flows through the heater 45. Since the heater 45 is made of stainless steel or a high nickel alloy, the electric resistance is larger than that of the annular conductor 2, and the heater 45 becomes high temperature due to an induced current flowing through the heater 45 and Joule heat generated by the electric resistance of the heater 45. . As a result, the food 60 disposed in the heating chamber 10 is radiated from the ceiling wall 14 and the heater 45, and convection is transferred by the air in the heating chamber 10 heated to a high temperature by the ceiling wall 14 and the heater 45. Cooked by heat.

Next, another heating system according to Embodiment 5 will be described with reference to FIGS. FIG. 23 is a perspective view of a main part of another heating system 8 according to Embodiment 5 as viewed from the rear. FIG. 24 is a side sectional view of the heating system 8. As shown in FIGS. 23 and 24, in the heating system 8, the coil 3a of the induction heating device 1 is spirally wound around a part of the magnetic body 4a, and the coil 3b of the heater 45 is spirally wound around a part of the magnetic body 4b. Each coil is connected to a high-frequency power source 5. From the high frequency power supply 5, high frequency power may be supplied independently to each of the coils 3a and 3b, or high frequency power may be supplied integrally. Alternatively, the coil 3a and the coil 3b may be connected in series or in parallel to be connected to the high frequency power source 5. Note that the coil shown in FIG. 21 may be used in place of the coil 3a and the coil 3b shown in FIGS. Furthermore, the coils 3a and 3b shown in FIGS. 23 and 24 can be applied to the heating systems shown in FIGS.

As shown in FIG. 23, the annular conductor 2 has a horizontal portion 20a and a vertical portion 20b, similarly to the annular conductor 2 described in the first embodiment. Furthermore, it has the folding | returning part 20c by which the end of the perpendicular | vertical part 20b was turned up. As shown in the drawing, a part of the vertical portion 20 b and the folded portion 20 c are surrounded by the magnetic body 4 a to form a power feeding portion 24.

23 and 24, in the heating system 8, the ceiling wall 14 disposed facing the heating unit 25 of the annular conductor 2 is formed of punching metal. As the punching metal of the ceiling wall 14, for example, magnetic stainless steel or nonmagnetic stainless steel having a plate thickness of 0.3 to 0.5 mm and circular holes arranged in a staggered manner can be used. The ceiling wall 14 and the heating portion 25 of the annular conductor 2 are electrically insulated by an oxide film formed on the surface of the annular conductor 2. However, since the oil smoke etc. which came out of the foodstuff 60 through the hole of punching metal (ceiling wall 14) adheres to the heating part 25, and the said heating part 25 may corrode, the ceiling wall 14 and the heating part 25 are It is preferable to provide an insulating plate 44 formed of a nonmagnetic insulating material such as ceramic, heat-resistant glass, or mica plate.

FIG. 25 is a development view of the annular conductor 2. As illustrated, the annular conductor 2 is produced by cutting a copper plate. The heating portion 25 of the annular conductor 2 is not a simple loop shape but a shape that is bent a plurality of times. As shown in the figure, the widths W1 and W2 of the portion surrounded by the magnetic body 4a of the annular conductor 2, that is, the members on both sides of the broken line II-II (part of the vertical portion 20b and the folded portion 20c) are substantially equal lengths. (For example, W1 and W2 are each 1.0 times). Then, it is bent 180 ° at the broken line II-II in FIG. 25 (valley fold) (W1 + W2) / 2, and 90 ° at the broken line III-III (mountain fold) to form an L shape, as shown in FIG. In the heating system 8. By producing the annular conductor 2 as described above, the electric resistance of the power feeding section 24 can be easily reduced without increasing the length of the power feeding section 24 of the annular conductor 2 to generate heat during heating. Can be suppressed.

The length of the widths W1 and W2 may be 1.5 times or 2.0 times the above length, and the member may be bent twice or three times, for example, or the lengths of the widths W1 and W2 may be The power feeding unit 24 may be further reduced in size by 0.5. The shape of the heating portion of the annular conductor 2 is not limited to that shown in FIG. 25, and may be an arbitrary shape.

Next, the operation of the heating system 8 will be described. When high-frequency power is supplied from the high-frequency power source 5 to the coils 3a and 3b, high-frequency magnetic fluxes φa and φb using the magnetic bodies 4a and 4b as magnetic paths are generated, and the high-frequency magnetic flux φa is linked to the annular conductor 2 The high-frequency magnetic flux φb is linked to the heater 45, and induced current flows through the annular conductor 2 and the heater 45 by electromagnetic induction.

The heater 45 generates heat due to Joule heat generated by the induced current and its own electrical resistance. As described in the other embodiments, the annular conductor 2 induction-heats the ceiling wall 14 disposed in the vicinity of the heating unit 25 of the annular conductor 2. The high-frequency magnetic flux generated in the heating unit 25 is strongest in the vicinity of the copper plate of the heating unit 25, so that the ceiling wall 14 is inductively heated by generating an eddy current along the shape of the heating unit 25 of the annular conductor 2.

Since the ceiling wall 14 is punched metal, power is not consumed in the hole portion, and power is consumed in the remaining metal portion. Therefore, the power density of the metal portion is higher than that of a solid metal plate without holes, and the temperature of the metal portion of the punching metal is high when the power input to the coil 3a is the same. The heat generated by induction heating spreads to the periphery of the ceiling wall 14 due to heat conduction, but the ceiling wall 14 made of punching metal has few metal parts that contribute to heat conduction and has low heat conductivity. Thereby, it is suppressed that heat spreads around the ceiling wall 14.

Due to such an action, the ceiling wall 14 made of punching metal becomes locally hot even when the input power is low, and a lot of infrared rays are radiated from the locally hot part. The food 60 in the cabinet 10 is efficiently cooked by radiant heating with infrared rays.

In order to emit a large amount of infrared rays, it is desirable that the temperature of the ceiling wall 14 is 700 ° C. or higher. However, even at the high temperature, even if the magnetic stainless steel is used, the magnetism goes beyond the Curie point and the magnetic properties disappear. The ceiling wall 14 may be sufficient and the ceiling wall 14 of metal materials other than stainless steel may be sufficient. In addition, in order to increase the emissivity of infrared rays from the ceiling wall 14, it is possible to apply a black paint or to form an oxide film on the surface of the ceiling wall 14. In the heating system shown in FIGS. 14 and 15 of the third embodiment, the ceiling wall 14 and the bottom wall 15 may be formed of punching metal.

In the present embodiment, the ceiling wall 14 is induction-heated. However, the present invention is not limited to this, and any one of the right side wall 11, the left side wall 12, or the bottom wall 15 may be induction-heated. Alternatively, the ceiling wall 14 may be formed of an insulator, and an object to be heated made of metal disposed in the vicinity of the ceiling wall 14 as shown in FIG.

The embodiment disclosed this time is an example, and the present invention is not limited to this. The present invention is defined by the scope of the claims rather than the scope described above, and includes all modifications within the scope and meaning equivalent to the scope of the claims.

Claims (16)

1. Coils,
   A high frequency power supply for supplying a high frequency current to the coil;
   Having a one-turn annular conductor constituting an electrical closed circuit;
   The annular conductor includes a heating unit that induction-heats a nearby object to be heated,
   A high-frequency magnetic flux generated by the coil and a power feeding unit interlinking,
   An induction heating apparatus, wherein a magnetic material is arranged so that a high-frequency magnetic flux generated by the coil is interlinked at a feeding portion of the annular conductor.
2. The induction heating apparatus according to claim 1, wherein the annular conductor is formed of a metal plate.
3. The induction heating apparatus according to claim 2, wherein the heating portion of the annular conductor is formed with a plurality of current paths.
4. The induction heating apparatus according to any one of claims 1 to 3, wherein the magnetic body is provided so as to surround an outside of the annular conductor.
5. A heating chamber in which at least a part of the bottom wall is formed of an insulating material;
   A heating system having a microwave generating means for irradiating microwaves in the heating chamber,
   The heating system includes the induction heating device according to any one of claims 1 to 4,
   A heating system in which a heating part of an annular conductor in the induction heating device is arranged below the bottom wall of the heating cabinet.
6. The heating chamber has a metal wall,
   The heating system according to claim 5, wherein a power feeding part of the annular conductor is arranged outside the heating chamber from the metal wall.
7. The heating system according to claim 6, wherein the annular conductor, the coil, and the metal wall are electrically connected.
8. A heating system having a heating chamber in which at least a part of a wall is made of a conductor,
   The heating system includes the induction heating device according to any one of claims 1 to 4,
   A heating system, wherein a heating portion of an annular conductor in the induction heating device is arranged so that at least a part of the heating chamber faces a wall made of a conductor.
9. The heating system according to claim 8, wherein at least a part of the wall is a magnetic metal.
10. The heating system according to claim 8, wherein at least a part of the wall is a plate-like member mainly composed of carbon.
11. The heating system according to claim 8, wherein at least a part of the wall is punched metal.
12. A heating system having a heating chamber in which at least a part of a wall is formed of an insulating material,
    The heating system includes the induction heating device according to any one of claims 1 to 4,
    A heating system, wherein a heating part of an annular conductor in the induction heating device is arranged so that at least a part of the heating chamber faces a wall formed of an insulator.
13. A top plate on which an object to be heated is placed;
    The induction heating device according to any one of claims 1 to 4, further comprising:
    A heating system, characterized in that a heating portion of an annular conductor in the induction heating device is arranged facing the top plate.
14. A box-shaped heating chamber;
    A one-turn heater constituting an electrical closed circuit disposed inside the heating chamber;
    A coil disposed outside the heating chamber;
    A high frequency power supply for supplying a high frequency current to the coil;
    A heating system comprising a magnetic body arranged so that a high-frequency magnetic flux generated from the coil interlinks with the heater,
    The heating system includes the induction heating device according to any one of claims 1 to 4,
    A heating system, characterized in that a heating portion of an annular conductor in the induction heating device is arranged facing at least one wall constituting the heating chamber.
15. The heating system according to claim 14, wherein the coil is a coil of the induction heating device.
16. The heating system according to any one of claims 5 to 15, wherein a copper plate or an aluminum plate is disposed on a side opposite to the heating portion of the annular conductor in the induction heating device.

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