JPH07249480A - Electromagnetic cooking apparatus - Google Patents

Abstract

PURPOSE:To provide an electromagnetic cooking apparatus in which the temp. difference between the central part and the intermediate part is small and which can perform uniform heating of an object to be heated. CONSTITUTION:An electromagnetic cooking apparatus is equipped with a heater coil 1 and a ring-shaped electroconductive plate 3, wherein the plate 3 adjusts the intensity of the magnetic field generated by the coil 1 in radial direction. The heater coil is formed by winding a conductor spirally for a number of turns. The conductive plate 3 is of such a structure that a slitted part 4 to tie the peripheral edge with the internal circumferential edge and shut the electrical connection between them is formed in a ring-shaped plate prepared by cutting off circularly the central part of a conductive disc of copper, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic cooker, and more particularly to a structure around a heating coil for uniformly heating an object to be heated.

[0002]

2. Description of the Related Art As an electromagnetic cooker, there is known a structure using a heating coil in which a conducting wire such as a litz wire is wound closely in a spiral shape in a circular or rectangular shape from the center toward the outer circumference. The upper part of FIG. 17 is a side view of the main parts of this type of electromagnetic cooker, in which a high-frequency current is passed through the heating coil 1 and a high-frequency magnetic field generated at this time causes a container 2 (object to be heated) formed of a magnetic material. Induction heating is shown.
The heating coil 1 is, for example, a flat spiral coil, and the container 2 is, for example, a SUS-based magnetic container. A top plate made of a glass material or a ceramic material is arranged between the heating coil 1 and the container 2, and when detecting the bottom temperature of the container 2, that is, the heating temperature, the central portion of the heating coil 1 is detected. The temperature sensor is usually pressed upward and toward the lower surface of the top plate.

[0003]

By the way, when induction heating is performed in an electromagnetic cooker using this type of heating coil 1, the number of magnetic flux linkages at the central portion and the peripheral portion of the heating coil 1 is the intermediate magnetic flux chain. It is relatively less than the number of crosses. Therefore, while the heating of the central portion and the peripheral portion of the object to be heated becomes insufficient,
On the contrary, the middle part is abnormally heated. In particular, heating at the center is weak.

For example, in the example of FIG. 17, 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. this is,
This means that it is not suitable for cooking where a uniform heating temperature is required.

In the case of using a temperature detector,
Since the top plate is usually made of a material with a low thermal conductivity, the conventional point-wise temperature detection will result in extremely poor accuracy when the bottom of the container, which is the object to be heated, has irregularities. There was a problem. It is conceivable to increase the sensor surface (metal surface) of the temperature detector to detect the temperature on a wide surface of the top plate, but then, an induced current flows in a loop shape on the sensor surface, and the magnetic field from the heating coil 1 is shielded. As a result, the heating of the container 2 is hindered or the sensor surface itself is induction-heated, so that there is a problem that practical detection accuracy cannot be obtained.

In view of the above problems, an object of the present invention is to provide an electromagnetic cooker having a structure capable of uniformly heating an object to be heated. Another object of the present invention is to provide an electromagnetic cooker configured to enable accurate temperature detection.

[0007]

An electromagnetic cooker according to a first aspect of the present invention is an electromagnetic cooker comprising a heating coil formed by winding a conductive wire in a spiral shape, wherein the object to be heated is induction-heated by the heating coil. An annular conductive plate having at least one slit connecting the outer peripheral edge and the inner peripheral edge is disposed on the side of the coil to be heated.

An electromagnetic cooker according to a second aspect of the present invention is characterized in that, in the structure of the first aspect of the present invention, the plurality of annular conductive plates having different diameters are concentrically arranged in the same plane at predetermined intervals.

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 annular conductive plate is located at a portion relatively different from the slit portion of another annular conductive plate adjacent in the radial direction. It is characterized by being formed.

An electromagnetic cooker according to a fourth aspect of the present invention is an electromagnetic cooker comprising a heating coil formed by winding a conductive wire in a spiral shape, and induction heating the object to be heated by the heating coil, wherein the object side of the heating coil is the object to be heated. In addition, a spiral conductive plate integrally formed with a required gap in the length direction is disposed.

An electromagnetic cooker according to a fifth aspect of the present invention is an electromagnetic cooker that includes a heating coil formed by winding a conductive wire in a spiral shape and induction heats an object to be heated by the heating coil. In addition, a plurality of slit portions are radially formed from the central hole portion toward the peripheral portion, and a conductive plate that connects at least one slit portion to the outer peripheral edge thereof is provided.

An electromagnetic cooker according to a sixth aspect of the 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. .

An electromagnetic cooker according to a seventh aspect of the present invention has a magnetic material disposed between the heating coil and a central portion of a conductive plate according to any one of the first to sixth aspects of the present invention, when the heating coil is energized. It is characterized in that a magnetic flux is collected in the magnetic material.

An electromagnetic cooker according to an eighth aspect of the present invention has a refrigerant supply means and a heat conductive tube body for passing the refrigerant supplied from the refrigerant supply means, and the surface of the heat conductive tube body is the first. It is characterized in that it is in contact with the surface or the outer peripheral surface of the conductive plate according to any one of the first to sixth inventions.

The electromagnetic cooker of the ninth invention comprises a heating coil formed by winding a conductive wire in a spiral shape, and a top plate arranged parallel to the main surface of the heating coil. In an electromagnetic cooker for induction-heating an placed object to be heated by the heating coil, the conductive plate according to any one of the first to sixth inventions is brought into contact with a predetermined portion of the top plate, and a temperature detector is attached. It is characterized in that a heat conductive plate is joined to the conductive plate. In addition, it is preferable that the temperature detector is attached to a portion that avoids a magnetic field from the heating coil.

An electromagnetic cooker according to a tenth aspect of the invention is an electromagnetic cooker comprising a heating coil formed by winding a conductive wire in a spiral shape, and induction heating the object to be heated by the heating coil, wherein the object side of the heating coil is the object to be heated. In addition, a plurality of ribs made of a long thin plate-shaped conductive plate are arranged so that their main surfaces face each other at a predetermined interval, and one of the above-mentioned conductive plates is attached to the thickness surface of the rib on the side of the object to be heated as an insulating member. It is characterized in that it is fixed through.

In the electromagnetic cooker of the eleventh aspect of the invention, in the configuration of the tenth aspect of the invention, the arrangement intervals of the plurality of ribs are made sparser from the outermost peripheral edge of the fixed annular conductive plate toward the center. It is characterized by In this case,
The rib at the center may be removed.

[0018]

In the electromagnetic cooker according to the first aspect of the present invention, the induction current is generated in the annular conductive plate by the high frequency magnetic field from the heating coil. Of this induced current, the current flowing along the outer peripheral edge of the annular conductive plate is blocked by the slit portion and cannot be further circulated. Flows (current I _{3 in} FIG. 1). 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 flows intensively near the center. This current relatively strengthens the induced magnetic field near the center of the annular conductive plate. As a result, the central part of the object to be heated is heated more strongly, and the temperature difference from the intermediate part is reduced.

In the electromagnetic cooker according to the second aspect of the present invention, the induction current flowing through the outer peripheral edges of the plurality of annular conductive plates flows in a direction to cancel the high frequency current of the heating coil, while the current flowing through the inner peripheral edge intensifies the high frequency current. Acts like. Therefore, the distribution of the heating temperature in the object to be heated can be adjusted by appropriately setting the width (radial length) of each annular conductive plate and the arrangement interval thereof.

Further, in the configuration of the third invention in which the positions of the slit portions formed in the plurality of annular conductive plates are relatively different from each other, the direction in which the current flows to the inner peripheral edge or the outer peripheral edge of one annular conductive plate and the adjacent Since the directions of the currents flowing through the outer peripheral edge or the inner peripheral edge of the provided annular conductive plate are always opposite and abrupt temperature increase or decrease is suppressed, the heating temperature of the object to be heated 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. Similar to the cases of the second and third inventions, the strength is relatively increased and the heating temperature of the object to be heated becomes uniform.

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 portion is relatively strengthened, and the object to be heated can be uniformly heated.

In the electromagnetic cooker according to the sixth aspect of the invention, the induced current flowing in the circumferential direction on 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.

According to the above inventions, the heating pattern is remarkably improved as compared with the prior art, but the heating temperature at the central portion of the conductive plate is relatively lower than the temperature at the peripheral portion. Therefore, like the electromagnetic cooker according to the seventh aspect of the invention, a magnetic material is arranged between the heating coil and the central portion of the conductive plate so that the magnetic flux gathers when the heating coil is energized. ,
The induced current in the central portion of the conductive plate relatively increases, and the heating temperature in the central portion rises.

In the electromagnetic cooker of the eighth aspect of the present invention, the surface or outer peripheral surface of the conductive plate is cooled by passing the refrigerant supplied from the refrigerant supply means through the heat conductive tube. If the conductive plate is overheated by the induced current,
Even if the object to be heated is partially overheated by the induction heating, the heating part is efficiently cooled, and a proper heating pattern is obtained.

In the electromagnetic cooker of the ninth invention, the heat generated by the conductive plate in contact with the top plate is transmitted to the heat conductive plate body, and this heat is further transmitted to the temperature detector, so that it is placed on the top plate. Even if the object to be heated has irregularities, it is possible to detect the temperature in a relatively large area. Also, the temperature detector is
Since it is attached to a portion that avoids the magnetic field from the heating coil, the detection accuracy is further enhanced.

In the electromagnetic cooker of the tenth invention, the conductive plate is
Since it is fixed to the thickness surface of the rib through the insulating member,
The direction of the induced current on the conductive plate does not change under the influence of these ribs. Further, since the portion of each rib that receives the induction of the heating coil is a thick surface having an extremely small area, it is difficult for eddy currents due to the induction to flow and the influence on the magnetic field distribution is reduced. The heat generated in the conductive plate is transmitted to the rib through the insulating member and radiated through the main surface thereof.

Since the central portion of the conductive plate used in each invention is selectively heated, if a large number of ribs are present at that portion, it is subjected to induction heating due to the induced current on the conductive plate, and a large current flows and the amount of heat generated is increased. Will increase. Therefore, as in the eleventh aspect of the invention, the ribs are arranged closer to each other toward the center, so that the induction heating by the conductive plate can be suppressed.

[0029]

Embodiments of the present invention will now be described in detail with reference to the drawings. (First Embodiment) FIG. 1 (a) is an internal plan view of an electromagnetic cooker according to the first embodiment of the present invention, and FIG. 1 (b) is a sectional view taken along line AA. This embodiment shows an example of an electromagnetic cooker according to the first aspect of the present invention, which has a flat spiral heating coil 1 and an annular conductive plate 3. The heating coil 3 is formed by winding a large number of conducting wires such as a litz wire in a spiral shape in the same plane as in the conventional case. Further, the annular conductive plate 3 connects an outer peripheral edge and an inner peripheral edge to an annular plate obtained by hollowing out a central portion of a conductor disk made of a copper plate or the like in a circular shape, and a slit portion 4 for interrupting electrical connection therebetween. Is formed.

Although the example of FIG. 1 is an example in which the slit portion 4 is formed in only one place, the slit portion 4 may be formed in two or more places. For example, FIG. 3 shows an example in which three slits 4 are formed. This annular conductive plate 3 is shown in FIG.
As illustrated in the upper stage, the heating coil 1 is arranged on the container 2 side. A top plate (not shown) is arranged between the annular conductive plate 3 and the container 2. FIG. 2 will be described later.

In the electromagnetic cooker constructed by using the annular conductive plate 3, in FIG. 1A, when a high frequency current I ₁ is passed through the heating coil 1, an induction magnetic field is generated on the coil surface of the heating coil 1. To do. At the same time, the first induced current I ₂ flows through the annular conductive plate 3 in the direction of canceling this induced magnetic field.

Here, the first induced current I ₂ tries to flow in the opposite direction to the high frequency current I ₁ of the heating coil 1,
Since it is blocked by the slit portion 4, the entire annular conductive plate 3 cannot make a circuit. Therefore, the second induced current I ₃ , which is a large current collected near the slit 4, moves along the inner peripheral edge of the annular conductive plate 3 in the opposite direction to the first induced current I ₂ , that is, the heating coil. The high-frequency current I _{1 of 1} flows in the same direction. Then, in this case, the first induced current I ₂ flowing through the outer peripheral edge of the annular conductive plate 3 is offset because it is in the opposite direction to the high frequency current I ₁ of the heating coil 1. Therefore, the object to be heated cannot be induction-heated at this portion, but near the inner peripheral edge of the annular conductive plate 3, the high frequency current I ₁
Since the second induced current I3 and the second induced current I3 have the same direction, the magnetic fields generated by these currents strengthen each other, and the annular conductive plate 3
A large induced magnetic field is generated near the inner peripheral edge of.

That is, as a result, it is possible to obtain the same effect as that when the coil current components of the width of the annular conductive plate 3 are aggregated and generated near the inner peripheral edge of the annular conductive plate 3. By utilizing this effect, a part of the current in the middle part of the heating coil 1 having a relatively strong magnetic field can be selectively moved to the weak magnetic field part in the central part of the heating coil 1, and It becomes possible to raise the heating temperature of the central part.

The upper part of FIG. 2 illustrates the case where the container 2 is induction-heated by the electromagnetic cooker of this embodiment. The lower part of FIG. 2 shows an example of measurement of the temperature distribution on the surface of the container 2 after the container 2 is cooked for a predetermined time by the electromagnetic cooker shown in FIG. 1. In this case, as compared with the temperature distribution in the conventional example shown in FIG. 13, it can be seen that the temperature of the central portion C rises by about 70 ° C. It should be noted that substantially the same result is obtained when the electromagnetic cooker having the configuration of FIG. 3 is used.

(Second Embodiment) FIG. 4 is a plan view of a conductive plate portion of an electromagnetic cooker according to a second embodiment of the present invention and its AA.
FIG. This embodiment shows an example of an electromagnetic cooker according to the second invention. The elements having the same or equivalent functions as those in the first embodiment will be described with the same reference numerals. In this embodiment, a plurality of annular conductive plates 5 having different diameters are used.
6 and 7 are arranged between the heating coil 1 and the container 2.
These annular conductive plates 5, 6 and 7 have the same shape as the annular conductive plate 4 described in the first embodiment. That is, at least one slit portion 4 connecting the outer peripheral edge and the inner peripheral edge is formed.

The annular conductive plates 5, 6, 7 are arranged concentrically on 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 in each annular conductive plate 5, 6, 7 is formed at a position relatively different from the slit portion of another adjacent annular conductive plate. The illustrated example shows an example in which the layers are alternately formed at positions having a difference of 180 degrees.

In the electromagnetic cooker thus constructed, as in the case of the first embodiment, the second induction current I ₃ flowing near the inner peripheral edge of each of the annular conductive plates 5, 6, 7 is used to generate the respective electric current. The magnetic fields near the inner peripheral edges of the annular conductive plates 5, 6, 7 are strengthened. Further, since the slit portion 4 is formed at a relatively different position of each annular conductive plate, the first induced current I ₂ and the second induced current I ₃ of the adjacent annular conductive plate are in different directions. Flow, and the local rise or fall of the magnetic field is suppressed. As a result, the induced magnetic field of the container 2 can be adjusted more uniformly.

(Third Embodiment) FIG. 5 is a plan view of a conductive plate portion of an electromagnetic cooker according to a third embodiment of the present invention. This embodiment shows an example of an electromagnetic cooker according to the third invention. Note that elements having the same or equivalent functions as those in the first and second embodiments are designated by the same reference numerals and described. The conductive plate used in this embodiment is almost the same as that described in the second embodiment, except for the following points. That is, the other end 5B of the annular conductive plate (element) 5 located on the innermost side and having the slit portion 4 at its one end 5A is joined to one end 6A of a larger annular conductive plate (element) 6 located on the outer periphery thereof, Further, the other end 6B of the annular conductive plate (element) 6
Is joined to one end 7A of a larger annular conductive plate (element) 7 located on the outer periphery thereof. This constitutes one spiral conductive plate in which each element is integrally formed.

In this embodiment, the first and second induced currents I ₂ and I ₃ act on the spiral conductive plate in a complex manner 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 each example, the strength is relatively increased, and uniform heating of the container is possible.

The upper part of FIG. 6 illustrates the case where the container 2 is induction-heated by the electromagnetic cooker of this embodiment. Further, the lower part of FIG. 6 shows an example of measurement of the temperature distribution on the surface of the container when the conductive plate of this example was used for heating under the same conditions as in the first example. In the temperature distribution of the conventional example shown in FIG. 13, the temperature difference between the temperature of the central portion C and the temperature of the intermediate portion M is about 120 ° C., whereas in the case of this embodiment, the temperature difference between the two is It has been improved to about 40 ° C., and it can be seen that an excellent effect of uniform heating is obtained at each stage.

(Fourth Embodiment) FIG. 7 is a plan view of a conductive plate portion of an electromagnetic cooker according to a fourth embodiment of the present invention. This embodiment shows an example of an electromagnetic cooker according to the fourth invention,
As in the third embodiment, three annular conductive plates (elements) 5,
In place of the shape in which 6 and 7 are joined in a stepwise manner, a conductive plate formed by integrally forming a conductive plate element having a required width into a circular spiral shape with a required gap during press forming of a copper plate or the like is used. There is.

In this embodiment, as in the third embodiment, the first and second induced currents I ₂ and I ₃ act in a complex manner and flow into the vicinity of the central portion thereof, so that the induced magnetic field at that portion is Relatively strengthening allows uniform heating of the container.

(Fifth Embodiment) FIG. 8 is a plan view of a conductive plate portion of an electromagnetic cooker according to a fifth embodiment of the present invention. This embodiment shows an example of an electromagnetic cooker according to the fifth aspect of the invention. Note that elements having the same or equivalent functions as those in the first and second embodiments are designated by the same reference numerals and described. In this embodiment, a conductive plate 9 having six slits 4 formed radially from the central hole 9a in the peripheral direction is arranged on the container side of the heating coil 1. 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.

In the electromagnetic cooker having such a structure, when the high frequency current I _{1 is} passed through the heating coil 1, the first induction current I ₂ is induced near the outer peripheral edge of the conductive plate 9. This first induced current I ₂ is applied to the outer peripheral edge and the central hole 9 as shown in the figure.
The direction is changed at the end near the slit portion 4 connecting a with the third induction current I ₄ in the direction of the central hole 9a, the second induction current I ₃ in the same direction as the high frequency current I _1, and the direction of the outer peripheral edge. As the fourth induced current I _5, it sequentially circulates along the edges around each slit portion 4.

At this time, the second induced current I ₃ strengthens the induced magnetic field by the high frequency current I ₁ as in the above-mentioned embodiments. On the other hand, the third and fourth induced currents I ₄ and I ₅ do not cancel the induced magnetic field caused by the high-frequency current I _1, and therefore do not weaken the induced magnetic field near the intermediate portion. After all, only the induced magnetic field around the central hole 9a becomes relatively strong, and the heating temperature difference in the container becomes small. The size of the conductive plate 9 in the radial direction can be arbitrarily designed according to the diameter of the heating coil 1 or the diameter of the bottom surface of the container.

(Sixth Embodiment) FIG. 9 is a plan view of a conductive plate portion of an electromagnetic cooker according to a sixth embodiment of the present invention. This embodiment shows an example of an electromagnetic cooker according to the sixth aspect of the invention, which uses a further improved version of the conductive plate 9 described in the fifth embodiment. That is, the conductive plate 10 according to this embodiment
As shown in the figure, for example, six slit portions 4 are radially formed in the peripheral direction from the central hole portion 10a, one of the slit portions 4 is connected to the outer peripheral edge, and the center is formed from a predetermined portion of the outer peripheral edge. Slit-shaped notch 1 in the direction of the hole
1 is formed. The number of the notches 11 is 5
It may be three or less, or seven 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.

According to the electromagnetic cooker having such a configuration, the first induction current I ₂ flowing in the circumferential direction on the outer peripheral edge of the conductive plate 10 is used.
Circulate while changing the direction at the end near each notch 11, such as a fifth induced current I ₆ in the direction of the central hole 10a and a sixth induced current I _{7 in} the direction of the peripheral edge. . These fifth and sixth induction currents I ₆ and I ₇ do not weaken the induction magnetic field by the heating coil 1 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 plan view of an essential portion of an electromagnetic cooker according to a seventh embodiment of the present invention, and FIG. 11 is its A- line.
It is A sectional drawing and the heating pattern figure of the container 2. FIG. This embodiment shows an example of an electromagnetic cooker according to the seventh aspect of the present invention. For example, the central void portion of the heating coil 1 is located near the central portion of the conductive plate 9 having the structure described in the fifth embodiment. The ferrite core 30 (magnetic material) is arranged at the position to be filled. The ferrite core 30 is, for example, a cylindrical core whose diameter and thickness are arbitrarily adjusted according to required heating strength,
The upper bottom thereof is arranged at a position facing the central hole (9a) of the conductive plate 9. The shape of the ferrite core 30 and the position where the ferrite core 30 is arranged are not necessarily limited to the illustrated example. For example, it may be a polygonal columnar ferrite core, or the ferrite core 30 may be brought into contact with the central hole portion (9a) of the conductive plate 9. In the electromagnetic cooker having such a configuration, the high-frequency magnetic flux generated when the heating coil 1 is energized is concentrated near the central portion of the conductive plate 9, and the induced current in that portion is increased. The heating temperature rises relative to the peripheral portion. Therefore, FIG.
As is clear from 1, the overall heating pattern of the container 2 is more uniform.

(Eighth Embodiment) FIG. 12 (a) is a plan view of a conductive plate portion of an electromagnetic cooker according to an eighth embodiment of the present invention.
(B) is the AA sectional view. This embodiment shows an example of an electromagnetic cooker according to the eighth invention. For example, a refrigerant pipe 31 is joined to the outer peripheral edge surface of the conductive plate 9 described in the fifth embodiment, and the conductive plate 9 and The refrigerant pipe 31 is in contact with the lower surface of the top plate 32. The refrigerant pipe 30 is a heat conductive pipe body such as a copper pipe, and has a refrigerant inlet S1 and a refrigerant outlet S2. Refrigerant inlet S1 and refrigerant outlet S2
Is attached to a refrigerant circulation mechanism (refrigerant supply means) not shown, and is configured so that the refrigerant composed of liquid or gas passes through the inside of the refrigerant pipe 30. A known coolant circulation mechanism can be used.

According to the electromagnetic cooker having such a structure, even if the bottom of the container is overheated when the heating coil 1 is energized or the conductive plate 9 generates heat due to the eddy current, the refrigerant pipe 31 receives the refrigerant. By supplying, the heating temperature can be adjusted appropriately. 12A and 12B show an example in which the refrigerant pipe 31 is joined to the outer peripheral edge surface of the conductive plate 9, the refrigerant pipe 31 is expected to be overheated. It is also possible to adopt a configuration in which it is joined to the surface portion. If the surface of the refrigerant pipe 31 is in contact with the conductive plate 9 and the top plate 32, the contact portion is cooled, so the refrigerant pipe 31 does not necessarily have to be joined.

(Ninth Embodiment) FIG. 13 (a) is a plan view of a conductive plate portion of an electromagnetic cooker according to a ninth embodiment of the present invention.
(B) is the AA sectional view. This embodiment shows an example of the electromagnetic cooker according to the ninth invention. For example, the conductive plate 9 described in the fifth embodiment is brought into contact with the lower surface of the substantially central portion of the top plate 32, and the temperature detector 34 is provided. The attached support plate (heat conductive plate body) 33 is joined to the conductive plate 9. In this case, the temperature detector 34 is attached to a portion of the support plate 33 that faces the lower surface of the top plate 32 in order to avoid the magnetic field from the heating coil 1.

In this way, the heat transmitted from the container bottom (not shown) to the top plate 32 when the heating coil 1 is energized and the heat generated by the conductive plate 9 due to the induced current are transmitted to the temperature detector 33 via the support plate 33. Be guided. Since the area where the conductive plate 9 contacts the top plate 32 is quite large,
The unevenness on the bottom of the container enables highly accurate temperature detection. Moreover, since the temperature detector 34 is attached to a portion that is not easily affected by the high frequency magnetic field generated from the heating coil 1, the detection accuracy can be further improved.

In the above first to ninth embodiments,
It is recognized that the provision of the conductive plates 3, 5 to 10 causes a slight energy loss, but this loss is 4 to 5% in any case, which is not a problem in practical use.

(Structure of Supporting Part of Conductive Plate) Next, a specific structure of the supporting part in the electromagnetic cooker when the conductive plates 3, 5 to 10 described in each of the above-mentioned embodiments are arranged will be described with reference to FIGS. 16
Will be described with reference to. FIG. 14 is a cross-sectional view showing the main part of this support structure, FIG. 15 (a) is a plan view thereof, and FIG.
Is a side view. This example corresponds to the configuration of the tenth invention. In these figures, 20 is the above-mentioned conductive plate 3,5-
10 and its surface is covered with an insulating filler 21. Further, 2 is a magnetic container, and 24 is a top plate made of, for example, ceramic that supports the container.

Reference numeral 22 is a rib made of a long thin plate-shaped conductive plate, for example, a copper plate. One thickness surface of the rib is directed to the heating coil (not shown), and the other thickness surface is directed to the top plate 24 (container 2). The main surfaces are arranged so as to face each other at a predetermined interval. As shown in FIG. 14, the ends of these ribs 22 are supported by insulating support members 23, respectively, and recesses are formed at the positions where the conductive plate 20 is fixed.

In the state where the conductive plate 20 is fixed in the recess, the thickness surface of the other rib 22 on the side of the top plate 24,
The surface of the insulating filler 21 covering the conductive plate 20 is included in the same plane, and the top plate 2 is placed on this plane.
Place 4.

In the electromagnetic cooker having such a support structure,
The conductive plate 20 is firmly fixed to the concave portion without being affected by the ribs 22 by the above-mentioned induced currents I ₂ and I ₃ .
Further, the conductive plate 20 generates heat when an electric current flows, but this heat is transmitted to each rib 22 through the insulating filling material 21 and is radiated through the main surface (front and back surfaces of the rib). The internal temperature rise is suppressed.

Since the rib 22 is made of a conductive plate, it is more excellent in thermal conductivity, heat dissipation efficiency, supporting strength of the conductive plate 20, life, etc. than ceramics, and is more suitable for this type of application. The insulating support member 23 firmly supports each end while cutting off the electrical connection between the ribs 22, so that the conductive plate 20 is fixed firmly inside the electromagnetic cooker. Also,
As shown in FIG. 15A, by aligning the ribs 22 in a certain direction, it becomes easy to blow air from the side surface along each rib 22 with a fan or the like, and the heat dissipation efficiency can be further improved. It will be possible.

FIG. 16 shows a modification of the configuration shown in FIG. 15A. As an example of the electromagnetic cooker according to the eleventh aspect of the invention, the ribs 22 are arranged at intervals closer to the center of the conductive plate 20. Here is an example. This is because the central portion of the conductive plate 20 is selectively heated, so that the influence of induction heating by the conductive plate 20 is suppressed by thinning out the ribs 22 at the relevant portion. Further, by doing so, it becomes possible to enhance the heat dissipation effect when the wind is applied to the main surface of the rib 22 using a fan or the like.

Although the present invention has been described with reference to a plurality of embodiments, the present invention is not limited to the above embodiments, 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 7 are used.
Although the description has been made on the assumption that it is an annular disc, it may be a square plate. 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, as the spiral annular conductive plate, a perfect circular spiral conductive plate has been described, but a square spiral spiral conductive plate 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, in the seventh to ninth embodiments, the conductive plate 9 of the fifth embodiment has been described as an example for the sake of convenience, but even the conductive plates having the structures described in the other embodiments have exactly the same effect. It can be expected. Further, in the support portion structure, the rib 22 may be composed of a thin plate annular member or one having a heat radiation fin. Instead of arranging the ribs 22 in a certain direction, the conductive plate 20 may be supported from a plurality of directions.

[0062]

As is apparent from the above description, according to the electromagnetic cooker of the first aspect of the present invention, since the strength of the magnetic field can be adjusted by the annular conductive plate, the heating temperature at the central portion of the object to be heated and the intermediate portion. The temperature difference from the heating temperature can be reduced, and the object to be heated can be heated uniformly. Thereby, the heating temperature distribution of the object to be heated such as the cooking container is improved.

Further, a plurality of annular conductive plates are concentrically provided as in the second invention, or a spiral conductive plate is used as in the third and fourth inventions to further uniformly heat the object to be heated. Can be converted. In the third and fourth inventions, since the annular conductive plate can be integrally formed, there is also an effect that the processing and attachment thereof are easy.

Further, according to the electromagnetic cooker of the fifth aspect of the invention, since the induction magnetic field of 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
It also has the effect of facilitating alignment with the heating coil.

In the electromagnetic cooker of the sixth invention, which is a further development of the fifth invention, in addition to the effect of the fifth invention, the strength of the induction magnetic field at the portion corresponding to the vicinity of the outer peripheral edge of the conductive plate is arbitrarily adjusted. There is an effect that becomes possible.

Further, according to the electromagnetic cooker of the seventh invention, the heating temperature near the central portion of the conductive plate is increased by the magnetic material disposed between the predetermined portion of the conductive plate and the heating coil. This is relatively higher than the peripheral portion, and has the effect of making the heating pattern of the object to be heated more uniform.

Further, according to the electromagnetic cooker of the eighth invention, even if the surface or the outer peripheral surface of the conductive plate is overheated, the heating portion is appropriately cooled by passing the refrigerant through the heat conductive tube. There is an effect that abnormal rise is suppressed.

Further, according to the electromagnetic cooker of the ninth invention, the heat generation of the top plate sensed by the entire conductive plate and the heat generation of the conductive plate itself can be guided to the temperature detector through the heat conductive plate body. It has the effect of enabling highly accurate temperature detection regardless of the bottom shape of the object to be heated. Furthermore, since the temperature detector is attached to the part that avoids the magnetic field from the heating coil, It has the effect of mitigating the impact.

Further, in the electromagnetic cooker of the tenth aspect of the invention, the conductive plate is firmly fixed by the plurality of ribs having a structure in which the eddy current does not easily flow, and the heat generated in the conductive plate is efficiently radiated by these ribs. be able to. In addition, in the configuration of the eleventh aspect of the invention, in which the ribs are arranged at an interval closer to the center from the outermost peripheral edge of the conductive plate, the effect of induction heating by the conductive plate is suppressed.

[Brief description of drawings]

FIG. 1A is a plan view showing a main part of an electromagnetic cooker according to a first embodiment of the present invention, and FIG. 1B is a sectional view taken along the line AA.

2 is a cross-sectional view showing an example in which a container is induction-heated by the electromagnetic cooker shown in FIG. 1, and a lower part is a graph showing a temperature distribution on the container surface in that case.

FIG. 3 is a plan view of another annular conductive plate of the electromagnetic cooker according to the first embodiment.

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

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

6 is a cross-sectional view showing an example of induction heating a container by the electromagnetic cooker of FIG. 5, and a lower part is a graph showing a temperature distribution on the container surface 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 plan view of a main part of an electromagnetic cooker according to a seventh embodiment of the present invention.

11 is a sectional view taken along the line AA of FIG. 10 and a heating pattern diagram of the container 2. FIG.

FIG. 12A is a plan view of a conductive plate portion of an electromagnetic cooker according to an eighth embodiment of the present invention, and FIG. 12B is a sectional view taken along line AA.

13A is a plan view of a conductive plate portion of an electromagnetic cooker according to a ninth embodiment of the present invention, and FIG. 13B is a sectional view taken along line AA.

FIG. 14 is a cross-sectional view of an essential part of a support portion structure of a conductive plate used in each example.

15A is a plan view of the support structure, and FIG. 15B is a side view thereof.

16 is a modified configuration example of FIG. 9, (a) is a plan view thereof, and (b) is a side view thereof.

FIG. 17 is a cross-sectional view showing an example in which a container is induction-heated by a conventional electromagnetic cooker, and a lower part is a graph showing a temperature distribution on the container surface in that case.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating coil 2 Container 3,5-10,20 Conductive plate 4 Slit part 9a, 10a Center hole part 11 Slit-like notch part 21 Insulation filler 22 Rib 23 Insulation support material 24,32 Top plate 30 Ferrite core 31 Refrigerant pipe (Heat conductive tube) 33 Support plate (Heat conductive plate) 34 Temperature detector

Claims (11)

[Claims] 1. An electromagnetic cooker comprising a heating coil formed by winding a conductive wire in a spiral shape and inductively heating an object to be heated by the heating coil, wherein an outer peripheral edge and an inner peripheral edge are provided on the object side of the heating coil. An electromagnetic cooker, characterized in that an annular conductive plate having at least one slit portion connecting with is disposed. 2. The electromagnetic cooker according to claim 1, wherein the plurality of annular conductive plates having different diameters are concentrically arranged in the same plane at predetermined intervals. 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 device. 4. An electromagnetic cooker comprising a heating coil formed by winding a conductor wire in a spiral shape and inductively heating an object to be heated by the heating coil, wherein the object side of the heating coil is in the longitudinal direction thereof. An electromagnetic cooker comprising a spiral conductive plate integrally formed with a required gap. 5. An electromagnetic cooker comprising: a heating coil formed by winding a conductive wire in a spiral shape, wherein the heating coil induction-heats an object to be heated; An electromagnetic cooker characterized in that a plurality of slits are radially formed in the peripheral direction and a conductive plate is provided which connects at least one slit with its outer peripheral edge. 6. The electromagnetic cooker according to claim 5, wherein the conductive plate has a slit-shaped notch formed in a direction from the predetermined portion of the outer peripheral edge toward the central hole. 7. The electromagnetic cooker according to any one of claims 1 to 6, wherein a magnetic material is provided between a predetermined portion of the central portion of the conductive plate and the heating coil, and the heating coil is energized. An electromagnetic cooker characterized in that magnetic flux sometimes gathers on the magnetic material. 8. The electromagnetic cooker according to any one of claims 1 to 7, further comprising: a coolant supply means; and a heat conductive tube body for passing the coolant supplied from the coolant supply means. The electromagnetic cooker, wherein the surface of the heat conductive tube is in contact with the surface or the outer peripheral surface of the conductive plate. 9. A heating coil formed by winding a conductive wire in a spiral shape, and a top plate arranged parallel to the main surface of the heating coil, and an object to be heated placed on the top plate. In an electromagnetic cooker that performs induction heating with the heating coil, a heat conductive plate body having the conductive plate according to any one of claims 1 to 6 in contact with a predetermined portion of the top plate and having a temperature detector attached thereto. An electromagnetic cooker characterized by being joined to the conductive plate. 10. An electromagnetic cooker comprising a heating coil formed by winding a conductive wire in a spiral shape and inductively heating an object to be heated by the heating coil, wherein a long thin plate-like member is provided on the object side of the heating coil to be heated. A plurality of ribs made of a conductive plate are arranged so that their main surfaces face each other at a predetermined interval, and the conductive plate according to any one of claims 1 to 7 is insulated on a thickness surface of the rib on the side of the object to be heated. An electromagnetic cooker characterized by being fixed via a member. 11. The electromagnetic cooker according to claim 10, wherein an arrangement interval of the plurality of ribs becomes sparser from the outermost peripheral edge portion of the fixed annular conductive plate toward the central portion.