JPH09154715A - Electromagnetic induction heating type cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of temperature detection precision due to the self heat generation of a lead wire. SOLUTION: A heat generation layer 8 is made to generate heat by an induction coil 14 and a pot 4 is heated. Also, a heat receiving plate 21 is disposed on a position opposite to the pot 4 near the heat generation layer 8 and a pot temperature sensor 22 composed of a negative characteristic thermistor is disposed on the back side of the heat receiving plate 21. Since the entire pot temperature sensor 22 and the heat receiving plate 21 are entirely constituted of a nonmagnetic material, the deterioration factor of the temperature detection precision due to the self heat generation of the lead wire is prevented.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a rice cooker that also serves as a jar,
Regarding an electromagnetic induction heating cooker that heats a removable container such as an electric grill, in particular, by improving the method for detecting the container temperature,
The present invention relates to an electromagnetic induction heating cooker with improved safety, cleanability, and appearance, and a simplified structure.

[0002]

Conventionally, the negative characteristic thermistor used for the temperature detecting means of this type of electromagnetic induction heating type cooker is burned mainly with a transition metal oxide mainly composed of Mn, Co and Ni. It consists of a fine ceramic semiconductor thermosensitive element bonded together, and has Dumet wires attached to both sides of the thermosensitive element and covered with glass.

This Dumet wire is a kind of lead wire selected in terms of corrosion resistance and strength, but since it is a magnetic material itself, it efficiently controls the temperature of the heat generating layer provided on the outer surface of the container. If a heat-sensitive element is attached near the coil for good temperature control, the lead wire will generate heat, and the effect of this is that the heat-sensitive element will detect a temperature higher than the normal temperature, and this will cause the temperature detection accuracy to deteriorate. . Therefore, conventionally, the control means is configured in consideration of the self-heating of the lead wire, or the lead wire is shortened as much as possible to suppress the heat generation amount of the lead wire, or there is a magnetic reflection effect of aluminum or the like. It was necessary to take some measures depending on whether or not the material had a magnetic-shield structure.

On the other hand, as a conventional cooking device of this type, for example, JP-A-7-111938 and JP-A-7-15525.
No. 1 gazette discloses that when foreign matter such as rice grains is caught between the heat-sensitive part of the temperature sensor, which is a temperature detecting means for detecting the temperature of the container, and the container, or the heat-sensitive part is deformed,
Since the accurate temperature of the container cannot be detected or temperature data different from the normal temperature is detected, various measures have been proposed to enhance the safety in that case. However, since those disclosed in these publications are premised on a coping method when the temperature detection accuracy is deteriorated, the temperature detection accuracy is accidentally deteriorated, and the cause is immediately removed (at the time of the next use). If it does, it does not cause much problem, but if the temperature detection accuracy is chronically deteriorated, normal heating and cooking will not be performed for a long period of time, which will cause the user to be dissatisfied.

Particularly in an electromagnetic induction heating type cooker in which the container itself generates heat, when the thermal coupling between the temperature sensor and the container is deteriorated, the temperature detected by the temperature sensor becomes lower than the actual temperature of the container, so the control means is Despite the temperature of the container is high, the temperature of the container is erroneously judged to be low and heating continues, and the food in the container burns, and in some cases the thermal fuse operates for safety. Or the body may melt. A method is also known in which the lid temperature sensor provided on the lid detects the temperature of the steam generated from the container and compares it with the container temperature to determine whether or not the detection of the container temperature is normal. However, when the lid is open or the temperature detection accuracy of the lid temperature sensor is poor, the effect is small and the above-mentioned problem occurs.

In view of the problems peculiar to the electromagnetic induction heating type cooker, the present invention therefore makes it possible to realize good cooking and heating control with high temperature detection accuracy without deteriorating the temperature detection accuracy of the container. The purpose is to provide a cooker.

[0007]

An electromagnetic induction heating type cooker according to the present invention as set forth in claim 1 has a container, a heat generating layer made of a magnetic material provided on an outer surface of the container, and facing the heat generating layer. A coil provided, an induction heating means for supplying a predetermined current to the coil to generate heat in the heat generating layer, a heat receiving section made of a non-magnetic material for receiving heat of the heat generating layer provided in the vicinity of the coil, and the heat receiving unit. A temperature detecting means provided on the back side of the portion, and a control means for controlling the heat generation state of the heat generating layer by the induction heating means based on the temperature detected by the temperature detecting means, and the temperature detecting means is made of a non-magnetic material. It is composed.

In this case, since the whole of the temperature detecting means including the lead wire and the heat receiving plate are all made of a non-magnetic material, it is possible to eliminate the factor of deterioration of the temperature detection accuracy due to self-heating of the lead wire as in the conventional case. it can.

The electromagnetic induction heating cooker according to the second aspect of the present invention includes a container, a heating layer made of a magnetic material provided on an outer surface of the container, and a coil provided so as to face the heating layer. , An induction heating means for supplying a predetermined current to the coil to heat the heating layer, a heat receiving portion made of a non-magnetic material provided in a non-contact state with the heating layer near the coil, and a back side of the heat receiving portion. And a control means for controlling the heat generation state of the heat generating layer by the induction heating means based on the temperature detected by the temperature detection means.

The heat receiving portion here is a member that receives radiant heat from the heat generating layer. The front side of the heat receiving portion is the side facing the heat generating layer of the container, and the back side of the heat receiving portion is the opposite side, that is, the side not facing the container.

When a predetermined high frequency current is supplied to the coil, the heat generating layer generates heat and heat radiation increases. Conversely, when the supply of the high frequency current to the coil is stopped, heat generation in the heat generating layer also stops and heat radiation occurs. Is less. Further, when the heat generating layer is heated when there is water in the container, heat is emitted from the heat generating layer according to the temperature condition of the water inside. Therefore, when the radiant heat from the heat generating layer is received by the heat receiving portion and the temperature of the heat receiving portion is detected by the temperature detecting means, the temperature of the container can be detected quickly and accurately. Further, since the temperature of the container can be detected in a non-contact state with the container by utilizing the radiant heat from the heating layer, the heating layer by the induction heating means is not affected by the contact variation between the container and the heat receiving part. The heat generation can be controlled well. Further, it is not necessary to intentionally bring the container and the heat receiving portion into contact with each other, and the structure around the temperature detecting means can be simplified.

Further, in the electromagnetic induction heating type cooker according to the present invention of claim 3, in addition to the structure of claim 2, the heat receiving part is made of a non-ferrous metal material having excellent heat conductivity as a base material, and the surface thereof is The surface layer has a higher absorption efficiency of infrared rays emitted from the heat generating layer than the base material.

In this case, since the base material has excellent thermal conductivity,
The radiant heat from the heat generating layer received on the surface of the heat receiving portion can be quickly transferred to the temperature detecting means. Further, since the base material is made of a non-ferrous metal material, even if the heat receiving portion is arranged near the coil,
The heat receiving plate portion hardly generates heat. Further, the surface layer having a higher infrared absorption efficiency than the base material can efficiently absorb the radiant heat in the infrared region from the heat generating layer on the surface side of the heat receiving plate, further improving the temperature detection accuracy of the temperature detection means.

Further, in the electromagnetic induction heating type cooker according to the present invention described in claim 4, in addition to the structure of claim 3, the base material of the heat receiving portion is an aluminum material, and the surface layer is an alumite coating layer. It is characterized by.

In this case, when the surface layer is formed of an alumite coating layer, the surface hardness of the heat receiving portion can be increased, and the surface layer does not peel off even when the foreign matter stuck to the heat receiving portion is removed.

According to a fifth aspect of the present invention, in addition to the configuration of the second aspect, the electromagnetic induction heating cooker includes a container accommodating portion made of an insulating material for accommodating the container, and the heat receiving portion is provided in the container. It is formed integrally with the accommodating portion.

In this case, the joint between the container housing portion and the heat receiving portion is inconspicuous and the appearance can be improved, and since there is no gap, water and dirt do not enter. Moreover, since the container housing portion and the heat receiving portion are integrated, the number of parts can be reduced.

Further, in the electromagnetic induction heating type cooker according to the present invention of claim 6, in addition to the structure of claim 2, the outer peripheral portion of the heat receiving portion is formed substantially on the same plane as the container accommodating portion for accommodating the container. Configured.

In this case, there is no protrusion on the inner bottom portion of the container accommodating portion, and the cleanability inside the container accommodating portion is improved. In addition, since the inner bottom of the container housing does not have an extreme depression, a large amount of water does not accumulate near the heat receiving part, and even if water enters the container housing, the temperature detection means may not detect the temperature error. Does not occur.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention applied to an electromagnetic induction heating rice cooker will be described below with reference to the drawings. In FIG. 1 showing an overall cross-sectional view, reference numeral 1 denotes a container body, which is a bottomed cylindrical inner frame 2 having an open top surface and an outer shell provided with the inner frame 2 to form an outer shell of the container body 1. And the frame 3. The inner frame 2 serving as a container housing is made of glass fiber-containing PET resin, and is formed in a shape substantially similar to the outer surface shape of the pot 4 serving as a container that is detachably housed in the inner frame 2.

The shape of the pan 4 for accommodating rice or water to be cooked is a bottomed cylinder having an open top.
At the top of the outer side surface of the pan 4, a flange-shaped handle portion 5 horizontally protruding outward is formed. The pan 4 is supported in a suspended state by the handle portion 5 thereof being placed on the upper end surface of the inner frame 2, and between the inner frame 2 and the pan 4 housed therein,
Except for the handle portion 5, a predetermined gap 6 of 1 to 4 mm is formed. In addition, the pan 4 is made of A3, which has excellent thermal conductivity and corrosion resistance.
A pan body 7 mainly made of 004 type aluminum material,
It is formed by the heat generating layer 8 provided from the outer bottom portion of the pot body 7 to the lower portion of the side surface. This heating layer 8 is a pan 4
And is made of a magnetic metal material made of ferritic stainless steel such as SUS430. Further, the inner surface of the pot 4 is coated with FEP resin to form a primer layer, and then the surface of the primer layer is printed with a FEP resin of a different color from the primer layer at a predetermined position by pad printing or the like (not shown). No.) is formed by printing, and a PFA resin of a transparent color is applied to form a fluororesin-based coating layer on the inner surface of the pot 4. On the other hand, the outer surface of the pot 4 is coated with a fluorine coating containing a silicone resin together with the heat generating layer 8 to form a fluorine resin coating layer.

Reference numeral 11 is a coil base.
Is made of glass-filled fiber PET resin, and is formed in a shape that is substantially similar to the peripheral shape from the bottom of the inner frame 2 to the lower outer periphery. The coil base 11 is attached to the lower side of the coil base attaching portion 12 which is vertically provided from the upper surface portion of the outer frame 3. The coil base 11 is located below the lower portion of the inner frame 2, and a predetermined gap 13 of 0.2 to 2 mm is formed between the outer side of the inner frame 2 and the coil base 11. Reference numeral 14 is an induction coil which is a coil for heating the heat generating layer 8 of the pan 4 by electromagnetic induction. The induction coil 14 is spirally wound around and fixed to the outer surface of the coil base 11, and sandwiches the coil base 11, the gap 13, the inner frame 2 and the gap 6 to face the heat generating layer 8 of the pan 4. There is. Further, a plate-shaped ferrite cover 15 that covers the induction coil 14 from the outside is attached to the coil base 11. This ferrite cover
No. 15 is made of iron oxide as a main raw material with high magnetic permeability,
Although not shown, it has a plurality of holes orthogonal to the winding direction of the induction coil 14. An insulating material is interposed between the ferrite cover 15 and the induction coil 14.

At the upper part of the outer surface of the inner frame 2, a body heater 16 for keeping the inner frame 2 composed of a cord heater or the like is provided, and a temperature fuse 17 is provided for safety. Further, as shown in FIG. 2, the bottom surface of the inner frame 2 is provided with a heat receiving plate 21 which is a heat receiving portion for receiving the radiant heat from the heat generating layer 8 of the pan 4. A pan temperature sensor 22, which is a temperature detecting means for detecting the temperature of the pan 4 by detecting the temperature of the heat plate 21, and a temperature fuse 23 are provided on the back side, that is, the lower side of the heat receiving plate 21 on the side opposite to the pan 4. Has been. The pan temperature sensor 22 is shown in FIG.
Further, as shown in FIG. 5, the alumina plate 24, which is a base member having a thickness of about 0.3 to 1.5 mm, which is a kind of non-magnetic material made of an insulating material, is mainly composed of Mn, Co, Ni or the like. The resistance changes depending on the temperature of the transition metal oxide, and is formed by printing a pattern portion 25 which is a temperature detecting element composed of a negative characteristic thermistor, and is a surface opposite to the insulating coated lead wire 26 and a temperature detecting surface. Is an alumina plate
The back surface 28 of the heat receiving plate 21 is provided in close contact with the flat surface portion 27 of 24. The lead wire 26 is made of a non-magnetic material such as brass or copper that has a low electric resistance.
It is attached by soldering with high temperature heat resistant solder 35. Furthermore, a silicone material or the like having excellent thermal conductivity may be filled between the heat receiving plate 21 and the alumina plate 24 to improve the thermal coupling between them. Thereby, the heat of the heat receiving plate 21 can be efficiently detected by the pan temperature sensor 22 which is a temperature detecting means,
The accuracy of detecting the temperature of the pan 4 by the pan temperature sensor 22 is improved.
On the other hand, the temperature fuse 23 has a temperature of 120 to 170 ° C., which is higher than the ambient temperature during normal use and lower than the temperature at which the inner frame 2 melts.
It is designed to operate at a predetermined temperature.

The structure of the heat receiving plate 21 itself will be described in detail with reference to FIGS. 1 to 3. The heat receiving plate 21 is an induction coil.
It is located in the vicinity of the heat-generating layer 8 which is opposed to 14 and which is the main heating part of the pan 4 and which self-heats. In the drawing, the heat receiving plate 21 is provided in the vicinity of the bottom of the pot 4, but the heat receiving plate 21 is provided at a position facing the side surface of the pot 4 in the vicinity of the heating unit that generates heat and heats the pot 4. May be. In addition, the distance between the heat receiving plate 21 and the heat generating layer 8 in the non-contact state is 0.1 to 4.0 mm,
A gap 29 of preferably 0.3 to 3.0 mm is formed.
The heat receiving plate 21 is formed on a base material 30 made of a non-ferrous metal material and at least a surface facing the heat generating layer 8, that is, a radiant heat receiving surface, and the infrared ray radiated from the heat generating layer 7 has a high absorption efficiency.
And a surface layer 31 higher than 30. The base material 30 is
Material thickness is about 0.3 to 2.0 mm, preferably 0.3 to
It is 1.0 mm and is formed of an aluminum material such as A1050 which is a non-magnetic material having excellent thermal conductivity.
Further, the surface layer 31 is for improving heat absorption. This is done by coating the surface of the base material 30 with a silicone resin type or a fluorine resin type or having a film thickness of 0.5-8.
An alumite coating of about μm is formed. The coating color of the surface of the heat receiving plate 21 is preferably a black color tone having good heat absorption, and in combination with the color tone of the surface of the inner frame 2, the surface of the inner frame 2 and the surface of the heat receiving plate 21 are integrated with the same or similar color tone. It is more preferable to form the appearance. When both the inner frame 2 and the surface of the heat receiving plate 21 are formed in a black color tone, when white rice grains or rice grains fall inside the inner frame 2, foreign matter is more noticeable and the cleaning property is improved. Further, in the case of forming an alumite coating as the surface layer 31 of the heat receiving plate 21, after the primary electrolysis, by the secondary electrolysis treatment of containing nickel oxide in the alumite coating, black in the absorption of nickel oxide for heat absorption. A good alumite coating is preferred. As a result, the temperature of the pot 4 during cooking is 100 to 15 which is slightly higher than the boiling temperature because the water in the pot 4 is heated.
The temperature of the infrared rays emitted from the outer surface of the pot 4 at this time is about 0 ° C., but most of the infrared rays are in the far infrared region of 3 to 4 μm or more, so the heat absorption of the heat receiving plate 21 in the far infrared region is improved. Therefore, the radiant heat of the pan 4 can be accurately absorbed. The surface of the heat receiving plate 21 is in the infrared wavelength range.
Average absorption rate (same as emissivity) of 8 to 10 μm
It is more preferable to use a material of 0% or more in terms of temperature detection accuracy. There is a certain correlation between the temperature T and the maximum peak wavelength λmax of infrared radiation, and T = 20
At 0 ° C., λ max = about 6.1 μm, at T = 150 ° C., λ max = about 6.8 μm, at T = 140 ° C., λ max = about 7.0 μm, and at T = 100 ° C., λ max = about 7.8 μ.
When m and T = 20 ° C., λ max = about 9.9 μm.

Next, the structure of the heat receiving plate 21 and its surroundings will be described in detail. As shown in FIG.
Is formed integrally with the inner frame 2 at the bottom of the, and the material thickness thereof is about 0.3 to 4.0 mm, preferably 0.3 to 1.0.
You may form in mm. In this case, the material of the heat receiving plate 21 is the same insulating material as the inner frame 2, that is, the plastic material, and the strength is weaker than that of the above-mentioned aluminum material, so it is necessary to design in consideration of impact resistance. ,
Further, since the thermal conductivity is also poor, it is necessary to set the temperature control data according to the detection status, but the inner frame 2 and the heat receiving plate
It has the advantages that 21 is integrated and the appearance is improved, and that the structure is simplified. Further, since there is no gap between the inner frame 2 and the heat receiving plate 21, even if water enters the inner frame 2, water does not enter the inside of the container body 1 at all, and since there is no gap, dirt does not enter. In addition, since the pan temperature sensor 22 is provided on the heat receiving plate 21 which is a non-metal part, it is easy to clean.
22 has the advantage that it is not affected by static electricity. Heat receiving plate
The configuration including the materials of 21 may be appropriately selected according to the purpose of use by utilizing each characteristic.

The heat receiving plate 21 may be separate from or integral with the inner frame 2, and its surface shape may be similar to or substantially flat with the outer surface of the bottom of the pot 4, but Board 21
A convex portion 33 that projects toward the pot 4 and that has an outer peripheral portion 32 that is inclined downward is formed substantially in the central portion. This perimeter
The outer surface of 32 may be substantially flush with the surface of the inner frame 2 or slightly higher (about 0.3 to 3.0 mm) than the surface of the inner frame 2. Convex portion 33 inclined toward the outer circumference
By forming the heat-receiving plate 21 on the surface of the heat-receiving plate 21, water is less likely to accumulate on the upper surface of the heat-receiving plate 21, and there is an advantage that the temperature detection error of the pot temperature sensor 22 is reduced. When the heat receiving plate 21 is separate from the inner frame 2, the heat receiving plate 21 is fixedly provided on the inner frame 2 in order to prevent water from entering from the joint between the heat receiving plate 21 and the inner frame 2. The structure is preferred. In this case, in order to further enhance waterproofness, the joint may be sealed with an elastic member interposed. Further, another communication gap 2A is provided between the outer peripheral upper part of the pot 4 and the inner peripheral upper part of the inner frame 2 so that the water entering the inner frame 2 is converted into steam from the gap 2A during cooking. It has a structure for discharging the lost water, which prevents erroneous detection of the pot temperature sensor 22 when water enters the inner frame 2.
Note that, instead of the communication gap 2A, the same effect can be obtained by providing a communication hole that communicates with the outside of the inner frame 2.

Reference numeral 41 is a control board provided in the lower portion of the vessel body 1, 42 is a heating board provided between the inner frame 2 and the outer frame 3 in the rear portion of the vessel body 1, and the heating board 42 Is configured by including an inverter circuit or the like for supplying a predetermined high frequency current to the induction coil 14. In addition, the switching element 43 forming this inverter circuit includes a radiator for heat dissipation.
44 are provided. The outer frame 3 for cooling the radiator 44, etc.
An exhaust port 45 is provided in the upper rear portion of the above, and an intake port 46 is provided in the lower rear portion and bottom portion of the outer frame 3. Further, 47 is a cord reel for winding a power cord 48 provided on the bottom front side of the outer frame 3.

Reference numeral 51 is a lid for covering the upper opening of the pan 4 so as to be openable and closable. The lid body 51 is attached to the outer lid 52, an outer lid cover 53 provided along the lower outer periphery of the outer lid 52, and a space below the outer lid 52 while forming a space. The heat sink 54 is made of an aluminum material and forms the lower surface. Reference numeral 55 denotes a lid packing sandwiched between the outer lid cover 53 and the heat radiating plate 54, and the lower end of the lid packing 55 comes into close contact with the handle portion 5 of the pot 4 when the lid body 51 is closed. Lid
A clamp button 56 is provided on the front side of the 51, and by pushing and operating the plump button 56, the lid 51 can be opened with a hinge 57 provided on the rear side of the lid 51 as a rotation center. Further, a lid heater 58 including a code heater for heating the heat sink 54 is provided on the upper surface, that is, the back surface of the heat sink 54. The lid heater 58 electrically forms a parallel circuit with the body heater 16. Further, on the back side of the heat dissipation plate 54, a lid temperature sensor 59 including a negative characteristic thermistor for detecting the temperature of the lower surface of the lid 51 is provided. Incidentally, 60 is a steam port for discharging the steam from the pan 4 to the outside.

Next, the circuit configuration of this embodiment will be described with reference to FIG. In the figure, reference numeral 61 denotes a microcomputer as a control means, which is, as is well known, a control device 62 and an arithmetic device 63 which constitute a microprocessor, a clock device 64, and a storage device including a ROM and a RAM. Equipped with 65. An input device 66 composed of an A / D converter is connected to the input side of the microcomputer 61. Through the input device 66, together with the pan temperature sensor 22 and the lid temperature sensor 59, the operation switch 67 and the pan 4 are connected. A load detection circuit 68 for detecting the presence / absence of a power failure and a power failure detection circuit 69 for detecting a power failure state are respectively connected. On the other hand, an output device 71 is connected to the output side of the microcomputer 61, and the induction heating device 72 for electromagnetically heating the pot 4 and the body heater 16 and the lid heater 58 are simultaneously connected via the output device 71. A heater driving means 73 for controlling the on / off of electricity is connected.
In addition to these, the output device 71 has a display drive circuit 75 of LED display means 74 for displaying operating states such as rice cooking and heat retention,
Display drive means 77 of LCD display means 76 for displaying time and the like
Buzzer 78 that informs the end of cooking rice when is connected
Buzzer drive means 79 for controlling the ringing of the is connected.

Then, the microcomputer 61 detects the operation signal of the operation switch 67 for starting cooking such as rice cooking and heat retention, the temperature data from the pan temperature sensor 22 and the lid temperature sensor 59, and the lower limit detection of the input current of the inverter circuit. By using the pan detection signal from the load detection circuit 68 by the input information and the time information from the timer 64 in addition to this input information, according to the control sequence preset in the ROM of the storage means 65, the induction heating means 72 The heating of the heating layer 8 is controlled, and the body heater 16 and the lid heater 58, the LED display means 74, the LCD display means 76, and the buzzer 78 are controlled. Reference numeral 81 is a power failure backup means connected to the output device 71, which guarantees the operation of the microcomputer 61 by the microcomputer drive circuit 82 at the time of power failure. The induction heating means 72 includes a microcomputer 61.
Induction coil generates a predetermined high frequency current based on the output signal from
A high frequency current generator 83 to be supplied to 14 and an output adjusting circuit 84 for adjusting the heating amount of the pan 4 are provided. Then, when a high frequency current is supplied to the induction coil 14, an alternating magnetic field is generated in the induction coil 14, and an eddy current is generated in the heat generating layer 8 of the pan 4 in the magnetic field. By being converted into, the heating layer 8 generates heat and the pot 4 is heated.

Further, in the heating control by the microcomputer 61, the control temperature of the pan temperature sensor 22 during rice cooking and heat retention is managed within a temperature range of -20 to 150 ° C. For example, in hot water cooking before cooking to promote water absorption of rice to be cooked, the temperature of the pan 4 is controlled to 45 to 60 ° C.,
The temperature at which the heating of the cooked rice is stopped and the temperature shifts to the spotty is based on the temperature detected by the pan temperature sensor 22 when the lid temperature sensor 49 detects the generation of steam. That is, after boiling, if the temperature rises by 5 to 15 ° C. with respect to the reference temperature, it is made uneven, and the heat retention control thereafter is set to 60 to 73 ° C. These temperature controls have the same configuration as the conventional rice cooker.

According to the above-described embodiment, the pot temperature sensor 22 as the temperature detecting means has Mn, C on the alumina plate 24 as the base member made of the non-magnetic and non-magnetic alumina ceramics.
Pattern part 25 consisting of a negative characteristic thermistor whose resistance changes with the temperature of the transition metal oxide mainly composed of
Is formed by pattern printing or thermal spraying, and a lead wire 26 made of a non-magnetic material such as brass or copper (Cu) is attached to the surface of the pattern portion 25 with a solder 35 which is a non-magnetic material. In other words, since the whole pan temperature sensor 22 that is a heat-sensitive element including the lead wire 26 and the heat receiving plate 21 are all made of a non-magnetic material, there is a factor that deteriorates the temperature detection accuracy due to self-heating of the lead wire 26 as in the conventional case. It can be eliminated, and the temperature accuracy in the electromagnetic induction heating cooker can be significantly improved. Further, by doing so, it is possible to obtain a highly reliable electromagnetic induction heating cooker in which cooking and heating control can be favorably performed and there is no precision variation.

That is, the heat receiving plate 21 provided near the induction coil 14 for receiving the heat of the heat generating layer 8 and the pan temperature sensor 22 provided on the back side of the heat receiving portion are both made of a non-magnetic material. Prevent the pan temperature sensor 22 from self-heating
It is possible to obtain an electromagnetic induction heating type cooker which has a high temperature detection accuracy and is capable of good cooking and heating control without deteriorating the temperature detection accuracy. In this embodiment, the heat receiving plate 21 and the heat generating layer 8 are separated from each other, but the heat receiving plate 21 and the heat generating layer 8 are in contact with each other, or the heat receiving plate 21 is intentionally moved by the elastic means. It is needless to say that the same action and effect can be obtained even by pressing the same against 8.

Further, in the electromagnetic induction heating type cooker as in this embodiment, the heating layer 8 which is the magnetic metal of the pot 4 is connected to the induction coil.
The alternating magnetic field from 14 heats the food in the pan 4 to generate heat. Therefore, when a predetermined high frequency current is supplied to the induction coil 14 facing the heat generation layer 8, the heat generation layer 8 generates heat and heat radiation increases, and conversely the supply of the high frequency current to the induction coil 14 is stopped. At times, there is a feature that the heat generation of the heat generating layer 8 is stopped and the heat radiation is reduced. In addition, when there is water in the pan 4, most of the heat generated in the heating layer 8 exchanges heat with water, so the pan 4 being cooked
When the heat generating layer 8 is caused to generate heat when there is water inside, heat is emitted from the heat generating layer 8 according to the temperature condition of the water inside. As described above, there is a correlation between the water temperature in the pot 4 and the temperature of the inner surface of the pot 4 that is in contact with water, and the amount of heat radiation from the heat generating layer 8, and the pot 4 is indirectly heated from the outside. Compared to the one heated by a heater, the temperature of the pan 4 is detected when the radiant heat from the heating layer 8 is detected, because the amount of heat radiation from the heating layer 8 directly reflects each temperature in the pan 4. It has the advantage of being fast and accurate. Therefore, the radiant heat from the heat generating layer 8 is received by the heat receiving plate 21, and the temperature of the heat receiving plate 21 is measured by the pan temperature sensor 22.
The temperature of the pan 4 can be detected quickly and accurately when configured to detect the temperature.

Further, by utilizing the radiant heat from the heat generating layer 8,
Since the temperature of the pan 4 such as dry-up can be detected without contacting the pan 4, the heat generation of the heating layer 8 by the induction heating means 72 is not affected by the contact variation between the pan 4 and the heat receiving plate 21. Can be well controlled.
Further, conventionally, in order to intentionally bring the heat-sensitive part of the temperature sensor into contact with the pan, elastic means such as a spring for pressing the heat-sensitive plate against the pan was required. It becomes unnecessary and the structure around the pan temperature sensor 22 can be simplified.

That is, the radiant heat from the heat generating layer 8 provided on the outer surface of the pan 4 is received by the heat receiving plate 21 made of a non-magnetic material and provided in a non-contact state with the heat generating layer 8, and the temperature of the heat receiving plate 21 is controlled. The heating layer 8 is detected by the temperature sensor 22 and is formed by the induction heating means 72.
If the heat generation state of No. 2 is controlled by the microcomputer 51, the response of the pan temperature sensor 22 according to the heating of the heating layer 8 and the stop of heating becomes good, and the heating layer 8 and the heat receiving plate 21 The temperature of the pan 4 can be accurately detected by the pan temperature sensor 22 without depending on the contact variation. Therefore, even if a foreign object is caught between the heat receiving plate 21 and the pan 4 or the surface of the heat receiving plate 21 is deformed, regardless of whether it is an accidental factor or a chronic factor, The temperature of the pan 4 during cooking can be detected accurately, and the pan is heated due to the erroneous determination of the control means as in the conventional case, the food to be cooked is burnt, the temperature fuse operates, and the like.
Alternatively, it is possible to completely eliminate defects such as melting of the main body and perform good cooking and heating control.

The heat receiving plate 21 of this embodiment is composed of a base material 30 made of a material having excellent thermal conductivity. Therefore, the heat receiving plate 21
Radiant heat from the heat generating layer 8 received on the surface of the pan can be quickly transferred to the pan temperature sensor 22 on the back side, and the temperature detection of the pan temperature sensor 22 is prevented from being delayed. Further, since the base material 30 is made of a non-ferrous metal material, even if the heat receiving plate 21 is arranged in the vicinity of the induction coil 14, the heat receiving plate 21 hardly generates heat, and the temperature detection error of the pan temperature sensor 22 is reduced. There is an advantage. Furthermore, since the surface layer 31 having a higher absorption efficiency of infrared rays radiated from the heat generating layer 8 than the base material 30 is formed on the surface of the heat receiving plate 21, the radiant heat from the heat generating layer 8, particularly in the infrared region, Can be absorbed efficiently on the surface side of the heat receiving plate 21,
It is possible to further improve the temperature detection accuracy of the pan temperature sensor 22. That is, the heat receiving plate 21 is made of a non-ferrous metal material having excellent thermal conductivity as the base material 30, and the surface layer 31 having a higher absorption efficiency of infrared rays emitted from the heat generating layer 8 than the base material 30 is formed on the surface thereof. Thus, it is possible to prevent the temperature detection delay of the pan temperature sensor 22 and further improve the temperature detection accuracy of the pan temperature sensor 22.

When the base material 30 is made of an aluminum material and the surface layer 31 is made of an alumite coating layer, the heat receiving plate 21 is more preferable than surface coating with a plastic paint.
The surface hardness can be increased, and even if foreign matter stuck to the heat receiving plate 21 is removed with Scotch bright or an abrasive, the surface layer 31 does not peel off. In particular, when the surface layer 31 is formed of a black alumite coating layer containing nickel oxide, the heat absorbing property of the heat receiving plate 21 is further improved. Further, in this case, the inner surface of the inner frame 2 serving as the container housing portion can be formed in a similar color tone, and the appearance of the inner frame 2 when the container 4 is taken out from the inner frame 2 is improved. Even if dirt becomes carbonized and sticks, it has an advantage that it becomes inconspicuous. Further, even if dirt adheres to the heat receiving plate 21, the temperature detection accuracy of the pan temperature sensor 22 is not affected by the contact with the pan 4, so that the maximum effect with no deterioration in performance can be obtained.

On the other hand, as shown in FIG. 6, when the inner frame 2 made of an insulating material for accommodating the pan 4 and the heat receiving plate 21 are integrally formed, the joint between the inner frame 2 and the heat receiving plate 21 is not conspicuous, and the outer appearance is shown. In addition to improving the property, there are no gaps, so that there is no risk of water or dirt entering. In addition, the inner frame 2 and the heat receiving plate 21
Since they are integrated, the number of parts can be reduced and the structure can be simplified.

Further, since the outer peripheral portion 32 of the heat receiving plate 21 is formed on substantially the same plane as the inner frame 2 for accommodating the pan 4, there is no protrusion from the inner bottom portion of the inner frame 2 to the outer peripheral portion 32 of the heat receiving plate 21. Therefore, the cleanability of the inner frame 2 is improved. Further, since the inner bottom portion of the inner frame 2 does not have an extreme depression, a large amount of water does not collect near the heat receiving plate 21, and even if water or the like enters the inner frame 2, the pot temperature sensor 22 No error in temperature detection. Therefore, while improving the cleanability of the inner frame 2, it is possible to prevent the temperature detection error of the pan temperature sensor 22 due to the accumulation of water or the like near the heat receiving plate 21.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention. For example, although the electromagnetic induction heating type rice cooker has been described in the embodiments, the present invention can be applied to all other electromagnetic induction heating type cookers.

[0042]

According to the electromagnetic induction heating type cooker of the present invention as defined in claim 1, a container, a heating layer made of a magnetic material provided on an outer surface of the container, and a coil provided so as to face the heating layer. An induction heating unit that supplies a predetermined current to the coil to heat the heating layer, and a heat receiving unit that is provided in the vicinity of the coil and is made of a non-magnetic material that receives the heat of the heating layer,
The temperature detecting means is provided on the back side of the heat receiving portion, and the control means for controlling the heat generation state of the heat generating layer by the induction heating means based on the temperature detected by the temperature detecting means, the temperature detecting means being non-magnetic. Since it is made of a material, self-heating of the temperature detecting means can be prevented, and the temperature detection accuracy of the container does not deteriorate, and the temperature detection accuracy is high and good cooking and heating control can be realized.

The electromagnetic induction heating cooker according to the second aspect of the present invention includes a container, a heat generating layer made of a magnetic material provided on the outer surface of the container, and a coil provided so as to face the heat generating layer. , An induction heating means for supplying a predetermined current to the coil to heat the heating layer, a heat receiving portion made of a non-magnetic material provided in a non-contact state with the heating layer near the coil, and a back side of the heat receiving portion. And a control means for controlling the heat generation state of the heat generation layer by the induction heating means on the basis of the temperature detected by the temperature detection means, and even by an accidental or chronic factor. Good cooking and heating control with high temperature detection accuracy can be realized without deteriorating the temperature detection accuracy of the container. Also,
It is also possible to simplify the structure around the temperature detecting means.

In addition to the effect of the invention of claim 2, the electromagnetic induction heating type cooker according to the invention of claim 3 has the heat receiving part made of a non-ferrous metal material having excellent thermal conductivity as a base material,
A surface layer is formed on the surface of which the absorption efficiency of infrared rays radiated from the heat generating layer is higher than that of the base material, which prevents temperature detection delay of the temperature detection means and improves the temperature detection accuracy of the temperature detection means. It is possible to further improve.

Further, in the electromagnetic induction heating type cooker according to the present invention described in claim 4, in addition to the effects of the inventions of claims 2 and 3, the base material of the heat receiving portion is an aluminum material, and the surface layer is an alumite coating. Since it is a layer,
The surface hardness of the heat receiving portion can be increased to prevent the surface layer from being peeled off.

In addition to the effect of the invention of claim 2, the electromagnetic induction heating cooker according to the invention of claim 5 further comprises a container accommodating portion made of an insulating material for accommodating the container,
Since the heat receiving portion is formed integrally with the container accommodating portion, the appearance and the cleanability can be improved and the structure can be simplified.

Further, in addition to the effect of the invention of claim 2, the electromagnetic induction heating type cooker according to the present invention of claim 6 has the outer peripheral portion of the heat receiving part substantially flush with the container accommodating part for accommodating the container. Since it is formed as described above, it is possible to prevent the temperature detection error of the temperature detection means due to the accumulation of water or the like in the vicinity of the heat receiving portion while improving the cleanability inside the container housing portion.

[Brief description of the drawings]

FIG. 1 is a schematic view of a rice cooker showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the same.

FIG. 3 is an enlarged cross-sectional view of the same heat receiving plate.

FIG. 4 is a perspective view of the same pan temperature sensor.

FIG. 5 is a front view of the same pot temperature sensor.

FIG. 6 is an enlarged cross-sectional view of a main part showing another embodiment.

FIG. 7 is a block diagram showing an electrical configuration.

[Explanation of symbols]

 2 Inner frame (container storage part) 4 Pan (container) 8 Heating layer 14 Induction coil (coil) 21 Heat receiving plate (heat receiving part) 22 Pan temperature sensor (temperature detecting means) 30 Base material 31 Surface layer 32 Outer peripheral part 61 Microcomputer (Control means) 62 Induction heating means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area A47J 36/02 A47J 36/02 B

Claims (6)

[Claims] 1. A container, a heat generating layer made of a magnetic material provided on an outer surface of the container, a coil provided so as to face the heat generating layer, and a predetermined current is supplied to the coil to heat the heat generating layer. Induction heating means, a heat receiving portion provided in the vicinity of the coil and made of a non-magnetic material for receiving the heat of the heat generating layer, a temperature detecting means provided on the back side of the heat receiving portion, and a temperature detected by the temperature detecting means. An electromagnetic induction heating cooker comprising: a control unit that controls the heat generation state of the heat generation layer by the induction heating unit, and the temperature detection unit is made of a nonmagnetic material. 2. A container, a heat generating layer made of a magnetic material provided on an outer surface of the container, a coil provided so as to face the heat generating layer, and a predetermined current is supplied to the coil to heat the heat generating layer. Induction heating means, a heat receiving portion made of a non-magnetic material provided in a non-contact state with the heating layer in the vicinity of the coil,
An electromagnetic induction comprising: a temperature detecting means provided on the back side of the heat receiving portion; and a control means for controlling the heat generation state of the heat generating layer by the induction heating means based on the temperature detected by the temperature detecting means. Heating cooker. 3. The heat receiving part is made of a non-ferrous metal material having excellent thermal conductivity as a base material, and a surface layer having a higher absorption efficiency of infrared rays emitted from the heat generating layer than the base material is formed on the surface thereof. The electromagnetic induction heating type cooker according to claim 2. 4. The electromagnetic induction heating cooker according to claim 3, wherein the base material of the heat receiving portion is an aluminum material, and the surface layer is an alumite coating layer. 5. The electromagnetic induction heating cooker according to claim 2, further comprising a container housing portion made of an insulating material for housing the container, wherein the heat receiving portion is formed integrally with the container housing portion. 6. The electromagnetic induction heating cooker according to claim 2, wherein an outer peripheral portion of the heat receiving portion is formed on substantially the same plane as a container housing portion for housing the container.