JPH07211443A - Electromagnetic cooker - Google Patents

Abstract

PURPOSE:To provide an electromagnetic cooker, e.g. a cooking container whose surface portion directed to a heating coil can be subjected to uniform induction heating. CONSTITUTION:An electrically conductive plate 3 coated with an electrically insulating member 2 is mounted on the bottom surface of a cooking container 1. The conductive plate 3 is for adjusting the strength of a radial magnetic field generated by a heating coil 32, and comprises an annular plate formed by the hollowing of the center portion of a conductor disk into a circular shape, with a slit portion 4 formed in the annular plate to connect the outer to inner peripheral edges of the plate and to interrupt an electrical connection between the edges. In use, the conductive plate 3 is directed to the heating coil 32 of the electromagnetic cooker and placed on a top plate made of a nonmetallic material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic cooker subject to induction heating by a heating coil of an electromagnetic cooker, and more particularly,
The present invention relates to an electromagnetic cooker having a structure in which a surface portion of a spirally-shaped conductive wire that faces a heating coil is uniformly heated.

[0002]

2. Description of the Related Art An induction cooker is a flat heating coil in which a conducting wire such as a litz wire is spirally wound in a circular or square shape from the center toward the outer circumference, and a non-magnetic coil arranged in parallel with the heating coil. An electric insulating top plate is provided, and an induction cooker such as a cooking container or a cooking plate is placed on the top plate for induction heating. The cooking container is, for example, a pot or a frying pan, and each of them is made of magnetic stainless steel, iron enamel, cast iron, titanium alloy, multilayer metal of these, or the like. As the cooking plate, for example, an iron plate,
Examples include magnetic stainless steel plates and titanium alloys. The top plate is usually made of non-magnetic material,
Recently, the top plate itself has been used as a cooking plate made of iron, magnetic stainless steel, or the like to directly perform induction heating.

FIG. 11 (a) is a side view of the main part of the electromagnetic cooker, in which a high frequency current is passed through the heating coil 32, and the high frequency magnetic field generated at this time causes the top plate 3 to move.
It shows a state of induction heating the cooking container 30 above.
Here, the heating coil 32 has a flat spiral shape as described above, and the top plate 31 is made of a non-magnetic material that is not affected by a high frequency magnetic field. Further, FIG. 11B shows a structural example of an electromagnetic cooker when a top plate 31 ′ formed of an iron plate, a magnetic stainless plate, a titanium alloy plate or a multilayer plate of these is used as a cooking plate.

[0004]

By the way, when induction heating is performed in a conventional electromagnetic cooker using a heating coil 32 made of a spiral conductor, the number of magnetic flux linkages at the central portion and the peripheral portion of the heating coil 32 is intermediate. It is relatively smaller than the number of magnetic flux linkages in the part. Therefore, the heating at the central portion and the peripheral portion of the surface portion of the cooking container 30 which points the heating coil 32 becomes insufficient, while conversely, the intermediate portion is abnormally heated. In particular,
Weak heating in the center.

For example, in the example of FIG. 11 (a), as shown in the lower part of the figure, the temperature of the central portion C and the peripheral portion P has a difference of about 120 ° C. from the maximum temperature in the intermediate portion M. In the case of FIG. 11B, the same tendency is obtained. As described above, the conventional electromagnetic cooker has a problem in that the heating temperature is not uniform and is not suitable for cooking which requires a uniform heating temperature.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention has an annular conductive plate (current transformer plate) in which a slit portion is formed on a surface portion of an electromagnetic cooker which points a spiral heating coil. ) Is provided to make the heating temperature of the surface uniform.

That is, the electromagnetic cooker of the first invention is an electromagnetic cooker that is subjected to induction heating by a heating coil of an electromagnetic cooker consisting of a spiral-shaped wire, and the surface portion pointing to the heating coil has an outer peripheral edge. It is characterized in that an annular conductive plate having at least one slit connecting the inner peripheral edge and the inner peripheral edge is mounted via an electrical insulating material.

In the electromagnetic cooker according to the second aspect of the present invention, in the configuration of the first aspect of the present invention, the plurality of annular conductive plates having different diameters are arranged concentrically in the same plane at predetermined intervals, and each annular conductive plate is arranged. It is characterized in that it is mounted on the surface portion via an electric miscellaneous material.

In the electromagnetic cooker according to the third aspect of the invention, in the configuration of the second aspect of the invention, the slit portion of each conductive plate is formed at a portion relatively different from the slit portion of another conductive plate adjacent in the radial direction. It is characterized by

An electromagnetic cooker according to a fourth aspect of the invention is an electromagnetic cooker which is subjected to induction heating by a heating coil of an electromagnetic cooker consisting of a spiral conductor, and has a flat shape with a predetermined gap on a surface portion facing the heating coil. It is characterized in that a conductive plate having a required width integrally formed in a spiral shape is mounted via an electric insulating material.

The electromagnetic cooker according to the fifth aspect of the invention is an electromagnetic cooker that is induction-heated by a heating coil of an electromagnetic cooker consisting of a spiral wire, and the surface portion facing the heating coil has a center hole portion. The present invention is characterized in that a conductive plate having a plurality of slits formed radially in the peripheral direction and at least one slit connected to the outer peripheral edge is mounted via an electrical insulating material.

The electromagnetic cooker according to a sixth aspect of the present invention is characterized in that, in the structure of the fifth aspect, a slit-like cutout portion is further formed from a predetermined portion of the outer peripheral edge of the conductive plate toward the central hole portion. .

[0013]

In the electromagnetic cooker according to the first aspect of the present invention, when the annular conductive plate is placed substantially parallel to the spiral heating coil on the electromagnetic cooker side, the high frequency magnetic field from the heating coil induces the annular conductive plate. An electric current flows. Of this induced current,
Since the current flowing along the outer peripheral edge of the annular conductive plate is blocked by the slit, it changes its direction at the end near the slit and flows toward the other peripheral edge (current I3 in FIG. 1B). . In this case, the current flowing along the inner peripheral edge of the annular conductive plate is in the opposite direction to the induced current flowing along the outer peripheral edge, and moreover, it concentrates near the central portion. Due to this current, the magnetic field near the center of the annular conductive plate becomes relatively strong. As a result, the central portion of the surface portion that faces the heating coil is heated more strongly than the intermediate portion, and the temperature difference in the surface portion becomes smaller.

In the electromagnetic cooker according to the second aspect of the present invention, the induction current flowing in the outer peripheral edge of each annular conductive plate flows in a direction to cancel the high frequency current of the heating coil, while the current flowing in the inner peripheral edge is the high frequency current. Acts to strengthen. Therefore,
By appropriately selecting the width (radial length) of each annular conductive plate and the arrangement interval thereof, it is possible to adjust the temperature distribution of the induction heating in the surface portion that faces the heating coil.

As in the third aspect of the invention, in the structure in which the positions of the slits formed in the plurality of annular conductive plates are relatively different from each other, the current is applied to the inner peripheral edge or the outer peripheral edge of one annular conductive plate. The current flowing direction and the direction of the current flowing to the outer peripheral edge or the inner peripheral edge of the adjacent annular conductive plate are always opposite, abrupt temperature rise or fall is suppressed, and the induction magnetic field in the electromagnetic cooker becomes more uniform.

In the electromagnetic cooker according to the fourth aspect of the present invention, the spiral conductive plate elements are integrally formed, and the induced currents compoundly act on each other and flow into the vicinity of the central portion thereof, so that the induced magnetic field at the relevant portion is the above. As in the case of the second and third inventions, the strength is relatively increased, and uniform heating of the surface portion facing the heating coil becomes possible.

In the electromagnetic cooker according to the fifth aspect of the present invention, the induced current flowing in the circumferential direction of the conductive plate is blocked by the slit portion connecting the outer peripheral edge and the central hole, and the conductive plate cannot be further circulated in the circumferential direction. It changes its direction at the end near the slit and flows toward the central hole. This current further flows along the edges around the radially formed slits, but the current flowing from the central hole of the conductive plate toward the outer peripheral edge and the current in the opposite direction are the high-frequency current of the heating coil. Since the induced magnetic field due to is not canceled out, only the induced magnetic field around the central hole becomes relatively strong. Therefore, it is possible to uniformly heat the surface portion that faces the heating coil.

Further, in the electromagnetic cooker according to the sixth aspect of the invention, the induced current flowing in the circumferential direction of the outer peripheral edge of the conductive plate circulates while sequentially changing its direction at the ends near the slit-shaped notches. Therefore, it is possible to adjust the strength of the magnetic field in the vicinity of the outer peripheral edge by appropriately changing the number of the cutout portions.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electromagnetic cooker of the present invention will now be described in detail with reference to the drawings, focusing on the case of a cooking container. (First Embodiment) FIG. 1A is a side sectional view of a cooking container 1 according to a first embodiment of the present invention, in which an annular conductive plate 3 coated with an electric insulating member 2 is attached to the bottom surface thereof. I will do it. At the time of use, as shown in the figure, the annular conductive plate 3 is placed on the non-metal top plate 31 so that the heating coil 32 of the electromagnetic cooker is oriented. The heating coil 32 is
As in the conventional case, it is configured by winding a large number of conducting wires such as litz wires in a flat spiral shape.

FIG. 1B is a plan view showing only the annular conductive plate 3 and the heating coil 32. As shown in the figure, the annular conductive plate 3 used in this embodiment is an annular plate in which the central portion of a conductor disk made of a copper plate or the like is hollowed out in a circular shape.
The slit portion 4 is formed by connecting the outer peripheral edge and the inner peripheral edge to interrupt the electrical connection between them.

In the cooking container 1 having such a structure, as shown in FIG.
In (b), when a high frequency current I1 is passed through the heating coil 32, an induction magnetic field is generated on the coil surface of the heating coil 32, but at the same time, an induction current is generated in the annular conductive plate 3 located on the bottom surface thereof.

Of this induced current, the first induced current I2 flowing through the outer peripheral edge of the annular conductive plate 3 is in the opposite direction to the high frequency current I1 of the heating coil 1, but is interrupted by the slit 4 and therefore annular. It is not possible to make a full circuit of the conductive plate 3. Therefore, the second induced current I3, which is a large current collected in the vicinity of the slit portion 4, moves along the inner peripheral edge of the annular conductive plate 3 in the opposite direction to the first induced current I2, that is, in the heating coil 32. The high-frequency current I1 flows in the same direction. In this case, the first induction current I2 is applied to the heating coil 32.
Since it is in the opposite direction to the high-frequency current I1 of, it is canceled. Therefore, induction heating cannot be performed in this part,
Since the high frequency current I1 and the second induced current I3 are in the same direction near the inner peripheral edge of the annular conductive plate 3, the magnetic fields generated by these currents strengthen each other, and a large induction occurs near the inner peripheral edge of the conductive plate 3. A magnetic field is generated.

That is, as a result, it is possible to obtain the same effect as that when the coil current component of the width of the annular conductive plate 3 is aggregated and the high frequency magnetic field is generated in the vicinity of the inner peripheral edge thereof. By utilizing this effect, a part of the current in the intermediate portion where the magnetic field is relatively strong in the heating coil 32 can be selectively moved to the weak magnetic field portion in the central portion, and the bottom portion ( It becomes possible to raise the heating temperature in the central part of the (heated surface).

Although the example of FIG. 1 (b) is an example in which the slit portion 4 is formed at one location on the annular conductive plate 3, the slit portion 4 may be formed at two or more locations. For example, FIG. 2 shows an example in which three slit portions 4 are formed at equal intervals from the center portion. In this case, of the induced currents, the first induced current I2 flowing in the outer peripheral edge is in the direction of canceling the magnetic field generated by the high frequency current I1, and the second induced current I2 flowing in the inner peripheral edge strengthens the magnetic field. Flow in the direction.

The upper part of FIG. 3 is a sectional view of the essential parts of the cooking container 1 of this embodiment during induction heating. In addition, the lower part of FIG.
It is an example of measurement of the surface temperature distribution after heating for a predetermined time when the cooking container 1 is cooked with a conventional electromagnetic cooker. In this case, as compared with the temperature distribution in the conventional example shown in FIG. 11, it can be seen that the temperature of the central portion C has increased by about 70 ° C. In addition,
Similar results were obtained when the conductive plate having the configuration of FIG. 2 was used.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, components having the same functions as those in the first embodiment will be designated by the same reference numerals. FIG. 4 is a plan view for explaining the structure of the conductive plate used in this embodiment.
6 and 7 are arranged on the bottom surface of the cooking container 1 that points the heating coil 32 when used. At that time, coating with an electrically insulating member is the same as in the first embodiment. These annular conductive plates 5, 6 and 7 each have a similar shape to the annular conductive plate 4 described in the first embodiment, and are formed with at least one slit portion 4 connecting the outer peripheral edge and the inner peripheral edge.

The annular conductive plates 5, 6, 7 are arranged concentrically in the same plane. That is, the ring-shaped conductive plate 5 located at the most central portion is inserted in the vicinity of the inner periphery of the ring-shaped conductive plate 6 having a larger diameter without electrical connection. Further, the annular conductive plate 6 is inserted in the vicinity of the inner periphery of the annular conductive plate 7 having a larger diameter without electrical contact.

Further, the slit portion 4 formed on each annular conductive plate 5, 6, 7 is formed at a position relatively different from the slit portion of another adjacent conductive plate. Alternately 1 in the example shown
An example is shown in which they are formed at positions having a difference of 80 degrees.

In the cooking container of this embodiment having the above-described structure, each annular conductive plate 5, 5 is used as in the case of the first embodiment.
The second induced current I3 flowing near the inner peripheral edges of 6, 7 strengthens the magnetic fields near the inner peripheral edges of the respective annular conductive plates 5, 6, 7. Further, since the slit portion 4 is formed at a relatively different position of each annular conductive plate, the first induced current I1 and the second induced current I3 of the adjacent conductive plate flow in different directions, The local rise and fall of the magnetic field is suppressed. As a result, the heating temperature of the entire bottom surface of the cooking container can be adjusted more uniformly.

(Third Embodiment) FIG. 5 is a plan view of a conductive plate mounted on the bottom surface of a cooking container according to a third embodiment of the present invention.
In this embodiment as well, components having the same functions as those in the above-described embodiments will be described with the same reference numerals. This conductive plate is almost the same as the conductive plate described in the second embodiment, except for the following points. That is, the other end 5B of the conductive plate 5 located on the innermost side and having the slit portion 4 at one end 5A thereof is joined to one end 6A of the larger conductive plate 6 located on the outer periphery thereof, and The end 6B is joined to one end 7A of the larger conductive plate 7 located on the outer periphery thereof. As a result, the flat spiral conductive plate is integrally formed.

In this embodiment, as in the above embodiments, the first induced current I2 and the second induced current I3 flow as shown in the drawing in actual use, but each conductive plate (element)
Since 5, 6, and 7 are integrally joined, these induced currents I2 and I3 act in a combined manner to relatively increase the strength of the induced magnetic field near the center, and It can be heated more uniformly.

The upper part of FIG. 6 illustrates how the cooking container 1'according to this embodiment is induction-heated. Further, the lower part of FIG. 6 shows an example of measurement of the surface temperature distribution when the cooking container 1'of this embodiment is heated under the same conditions as in the first embodiment. In the temperature distribution of the conventional example shown in FIG. 11, the temperature difference between the temperatures of the central portion C and the intermediate portion M is about 12
While it was 0 ° C., in the case of this example, the temperature difference between the two was improved to about 40 ° C., and it can be seen that an excellent uniform heating effect can be obtained at each stage.

(Fourth Embodiment) FIG. 7 is a plan view of a conductive plate mounted on the bottom surface of a cooking container according to the fourth embodiment of the present invention. This conductive plate 8 has a required width when press-molding a copper plate or the like, instead of a shape in which three conductive plates (elements) 5, 6 and 7 are joined stepwise as in the third embodiment. The conductive plate element of 1 is integrally formed in a round spiral shape in the length direction. By using such a conductive plate 8, it is possible to uniformly heat the entire bottom surface of the cooking container, as in the third embodiment.

(Fifth Embodiment) FIG. 8 is a plan view of a conductive plate mounted on the bottom surface of a cooking container according to a fifth embodiment of the present invention. In this embodiment, a conductive plate 9 having six slits 4 formed radially from the center hole 9a in the peripheral direction.
To use. As shown, one of the slit portions 4 is connected to the outer peripheral edge of the conductive plate 9. The number of slits 4 connected to the outer peripheral edge may be plural, and the number of slits may be arbitrary. The point that such a conductive plate 9 is covered with an electrically insulating material and attached to the bottom surface of the cooking container is the same as in each of the above embodiments.

In the cooking container having such a structure, in actual use, the first induced current I2 flows near the outer peripheral edge of the conductive plate 9 as in each of the above-described embodiments. This first induced current I2 is, as shown in the figure, the outer peripheral edge and the central hole 9a.
The third induction current I4 in the direction of the central hole 9a, the second induction current I3 in the same direction as the high frequency current I1, and the fourth induction in the outer peripheral direction are changed at the end near the slit portion 4 connecting A current I5 is sequentially circulated along the edges around each slit portion 4.

At this time, the second induction current I3 strengthens the induction magnetic field of the heating coil 32 due to the high frequency current I1. On the other hand, the third and fourth induced currents I4 and I5 do not cancel the induced magnetic field caused by the high frequency current I1 and therefore do not weaken the induced magnetic field near the middle portion. Eventually, only the induction magnetic field around the central hole 9a becomes relatively strong, and the central portion of the bottom surface of the cooking container mounted via the electric insulating material is heated relatively stronger than the intermediate portion thereof, and the entire heating is performed. The temperature difference becomes smaller. The size of the conductive plate 9 in the radial direction can be arbitrarily designed according to the diameter of the heating coil of the electromagnetic cooker or the diameter of the bottom surface of the cooking container to be mounted. Therefore, it becomes possible to easily adjust the heating distribution by the existing electromagnetic cooker by appropriately selecting the size of the conductive plate 9.

(Sixth Embodiment) FIG. 9 is a plan view of a conductive plate portion mounted on the bottom surface of a cooking container according to the sixth embodiment of the present invention. In this embodiment, a conductive plate 10 obtained by further improving the conductive plate 9 described in the fifth embodiment is used. That is, as shown in the figure, the conductive plate 10 has a central hole 10a.
From this, for example, six slits 4 are radially formed in the peripheral direction, one of the slits 4 is connected to the outer peripheral edge of the conductive plate 10, and slit-shaped cutting is performed from a predetermined portion of the outer peripheral edge toward the central hole. The notch 11 is formed. The number of notches 11 may be 5 or less or 7 or more. In addition, each notch 11 is preferably centered on a portion of the outer peripheral edge where the distance to each intersection is equal and the intersection of the extension line of each pair of slits in the peripheral edge direction and the outer peripheral edge is obtained. It is formed by slitting in the direction of the hole 10a. It should be noted that the point that the conductive plate 10 is mounted on the bottom surface of the cooking container via the electric insulating material is the same as in each of the above-described embodiments.

In the cooking container constructed by using the conductive plate 10 as described above, the first induced current I2 flowing in the circumferential direction on the outer peripheral edge of the conductive plate 10 is centered at each end near the notch 11. The fifth induced current I6 in the direction of the hole 10a and the sixth induced current I7 in the direction of the peripheral portion are circulated while changing their directions. These fifth and sixth induced currents I
6 and I7 do not weaken the magnetic field induced by the heating coil 22 as described above. Therefore, by appropriately changing the number of the cutout portions 11, it becomes possible to arbitrarily adjust the strength of the magnetic field near the outer peripheral edge.

(Seventh Embodiment) FIG. 10 is a side sectional view when the present invention is applied to a conductive top plate. The top plate 20 is formed by mounting a conductive plate 23 coated with an electric insulating member 22 on the back side of the plate main surface portion 21. The conductive plate 23 is used in the first to sixth embodiments, for example. At the time of use, as shown in the figure, the top plate 20 is set at a predetermined portion of the frame body of the electromagnetic cooker so that the conductive plate 23 points the heating coil 32.

In such a structure, by applying a high frequency current to the heating coil 32, the induced magnetic field in the vicinity of the central portion of the conductive plate 23 is relatively strengthened as in the first to sixth embodiments. Therefore, the heating temperature of the central portion of the top plate 20 is the conventional top plate 3 shown in FIG.
1 ', and the heating temperature difference in the entire plate main surface portion 21 becomes smaller. Therefore, a conductive top plate suitable for cooking that requires uniform heating can be realized.

In each of the first to seventh embodiments, the heat generated from the conductive plates 3, 5 to 10 and 23 can be used as the heating energy for the cooking container, which is economically advantageous. In each embodiment, the conductive plates 3, 5-10, 2
It is recognized that there is some energy loss by providing No. 3, but this loss is 4 to
It is 5%, which poses no problem in practical use.

Although the present invention has been described in detail above with reference to a plurality of embodiments, the main point of the present invention is that a conductive plate is provided on the surface of the electromagnetic cooker which is induction-heated by the heating coil of the electromagnetic cooker. Therefore, the present invention is not limited to the configuration of the above embodiment, and various design changes can be made without changing the gist thereof. For example, in the first to third embodiments, the conductive plates 3, 5 to 8 have been described on the assumption that they are circular disks, but they may be rectangular plates. Also, an example in which the central portion of the annular plate is hollowed out has been described, but it may be hollowed out into a rectangular shape. Further, in the fourth embodiment, the complete spiral spiral conductive plate 9 has been described, but a spiral spiral conductive plate 9 may be used. Further, in the fifth and sixth embodiments, a circular conductive plate has been described, but a rectangular plate may be used, and the lengths and arrangements of the slit portions 4 may be appropriately selected. Further, the conductive plates 3 to 10 are not necessarily limited to the flat plate structure, and can be appropriately bent according to the bottom shape of the electromagnetic cooker container.

Although the first to seventh embodiments have been described with reference to the cooking container and the top plate as an example of the electromagnetic cooker, the same description can be applied to the case of the cooking plate or the magnetic container used for the same purpose. It goes without saying that is true.

[0047]

As is apparent from the above description, according to the electromagnetic cooker of the first invention, the strength of the magnetic field of the heating coil can be adjusted by the conductive plate. This has the effect of suppressing the temperature difference between the heating temperature in the central portion and the heating temperature in the intermediate portion. As a result, the temperature distribution of induction heating by the flat spiral heating coil is improved, and the conventional problems are eliminated.

Further, by providing a plurality of conductive plates concentrically in the same plane as in the second invention, or by using a spiral conductive plate as in the third and fourth inventions, the temperature due to induction heating can be increased. The distribution can be made more uniform. In the third and fourth inventions, since the conductive plate can be integrally formed, there is also an effect that the processing and mounting thereof are easy.

Furthermore, according to the fifth aspect of the invention, since the induction magnetic field at the portion corresponding to the intermediate portion of the conductive plate is not canceled, the bottom surface of the object to be heated can be uniformly heated and the top plate of the electromagnetic cooker can be heated. It also has the effect of facilitating the alignment of.

Further, according to the sixth invention, in addition to the effect according to the fifth invention, there is an effect that the strength of the induced magnetic field at the portion corresponding to the vicinity of the outer peripheral edge of the conductive plate can be arbitrarily adjusted. The electromagnetic cooker may be a conductive top plate of an electromagnetic cooker in addition to the cooking container and the cooking plate, and has a wide range of application. In any case, the heat generated by the conductive plate can be used as it is as heating energy, which is economically advantageous.

[Brief description of drawings]

FIG. 1 (a) is a side sectional view of a cooking container according to a first embodiment of the present invention, and FIG. 1 (b) is a plan view illustrating the relationship between a conductive plate and a heating coil provided on the bottom surface thereof. is there.

FIG. 2 is a plan view of another conductive plate that can be used in the first embodiment.

3 is a cross-sectional view of an essential part for explaining a state of induction heating the cooking container of FIG. 1, and a lower part is a graph showing a temperature distribution on the surface of the container in that case.

FIG. 4 is a plan view of a conductive plate used in the second embodiment of the present invention, and a lower section is a cross-sectional view taken along the line AA.

FIG. 5 is a plan view of a conductive plate used in a third embodiment of the present invention.

6 is a cross-sectional view of an essential part for explaining how induction heating is performed on the cooking container equipped with the conductive plate of FIG. 5, and the lower part is a graph showing the temperature distribution on the surface of the container in that case.

FIG. 7 is a plan view of a conductive plate used in a fourth embodiment of the present invention.

FIG. 8 is a plan view of a conductive plate used in a fifth embodiment of the present invention.

FIG. 9 is a plan view of a conductive plate used in a sixth embodiment of the present invention.

FIG. 10 is a side sectional view of a conductive top plate according to a seventh embodiment of the present invention.

FIG. 11 (a) is a cross-sectional view of an essential part for explaining a state of induction heating a cooking container by a conventional electromagnetic cooker, and a lower part is a graph showing a temperature distribution on the container surface in that case,
(B) is a principal part side view which shows the example of a setting when the top plate of an electromagnetic cooker is formed with a conductive member.

[Explanation of symbols]

 1,1 'Cooking container (electromagnetic cooker) 2,22 Electric insulating member 3,5-10,23 Conductive plate 4 Slit part 9a, 10a Central hole part 11 Slit-like notch part 20 Conductive top plate (electromagnetic cooker) ) 31, 31 'Insulating top plate 32 Heating coil for electromagnetic cooker

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[Procedure amendment]

[Submission date] January 26, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

In the cooking container of this embodiment having the above-described structure, each annular conductive plate 5, 5 is used as in the case of the first embodiment.
The second induced current I3 flowing near the inner peripheral edges of 6, 7 strengthens the magnetic fields near the inner peripheral edges of the respective annular conductive plates 5, 6, 7. Further, since the slit portion 4 is formed at a relatively different position of each annular conductive plate, the first induced current I2 and the second induced current I3 of the adjacent conductive plate flow in different directions, The local rise and fall of the magnetic field is suppressed. As a result, the heating temperature of the entire bottom surface of the cooking container can be adjusted more uniformly.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuto Nishizaki 2-1, Shibasaki, Chofu City, Tokyo 3 Shimada Rika Kogyo Co., Ltd.

Claims (6)

[Claims] 1. An electromagnetic cooker which is induction-heated by a heating coil of an electromagnetic cooker comprising a spiral wire.
An electromagnetic cooker, wherein an annular conductive plate having at least one slit connecting an outer peripheral edge and an inner peripheral edge is formed on a surface of the heating coil which faces the heating coil via an electrical insulating material. 2. A plurality of the annular conductive plates having different diameters are concentrically arranged in the same plane at predetermined intervals, and the annular conductive plates are attached to the surface portion via an electric miscellaneous material. The electromagnetic cooker according to claim 1. 3. The electromagnetic wave according to claim 2, wherein the slit portion of each annular conductive plate is formed at a portion relatively different from the slit portion of another annular conductive plate adjacent in the radial direction. Cooking utensils. 4. An electromagnetic cooker which is induction-heated by a heating coil of an electromagnetic cooker made of a spiral wire.
An electromagnetic cooker characterized in that a conductive plate having a required width, which is integrally formed in a flat spiral shape with a predetermined gap, is attached to a surface portion facing the heating coil via an electric insulating material. 5. An electromagnetic cooker which is induction-heated by a heating coil of an electromagnetic cooker including a spiral wire,
A conductive plate, in which a plurality of slits are radially formed from the central hole toward the peripheral portion and at least one slit is connected to the outer peripheral edge, is attached to the surface portion facing the heating coil via an electrical insulating material. An electromagnetic cooker characterized by doing 6. The electromagnetic cooker according to claim 5, wherein the conductive plate has a slit-shaped cutout portion formed in a direction of the central hole from a predetermined portion of an outer peripheral edge of the conductive plate.