JP3218589B2 - Induction heating cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic induction heating type cooker such as a rice cooker.

[0002]

2. Description of the Related Art As described in, for example, Japanese Patent Publication No. 4-40004, there is known a rice cooker for heating a container for accommodating cooked items such as rice and water by electromagnetic induction. In this rice cooker, an air layer is provided between an inner frame (protection frame) for accommodating a container (pot) and the container, and a coil for induction heating is supported outside the inner frame by a coil cover. The coil is exposed to the air layer outside the inner frame. In this way, heat from the container is shielded by the air layer between the inner frame and the container, and radiant heat from the inner frame to the air layer outside the inner frame is suppressed, so that the air layer outside the inner frame is suppressed. The cooling of the coil exposed to the air is efficiently performed. The inner frame must be made of non-metal in order to perform electromagnetic induction, and must be in the shape of a cylinder with a bottom in order to accommodate a container.

[0003] By the way, the coil is supported on the inner surface side of the coil cover in a state of facing the bottom part and the lower part of the side surface of the container, and is mounted outside the inner frame.
The coil is formed into a spiral shape in advance according to the shape of the bottom part of the outer surface of the container, and the formed coil is attached to the inner surface of the coil cover by bonding or the like, and then mounted on the outside of the inner frame. There is trouble to keep.

In order to eliminate this trouble, the shape of the periphery of the bottom of the inner frame is made substantially similar to the shape of the periphery of the bottom of the outer surface of the container, and the bottom of the inner frame and the lower portion of the outer periphery are guided to directly connect the coil to the inner frame. It is also conceivable to use a method of spirally winding around and mounting the device. However, according to this method, when the coil is wound directly on the inner frame, the portion other than the coil wound portion is relatively large and hinders the work efficiency. Since the latter part, that is, the inner frame with the coil is bulky, it becomes difficult to transport and store the part before and after the operation.

[0005]

As described above, in a cooking device such as a rice cooker in which a container to be induction-heated by a coil is accommodated in an inner frame, conventionally, a coil disposed outside the inner frame. Since the coil was provided on the inner surface of the cover so that an air layer was formed between the inner frame and the inner frame, there was a problem that the coil had to be formed in advance during manufacturing, which required a lot of trouble. On the other hand, it is conceivable to wind a coil directly on the inner frame, but there are many manufacturing problems since the coil is limited in the inner frame.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide an electromagnetic induction heating type cooker in which a coil can be easily mounted and manufacturability can be improved.

[0007]

In order to achieve the above object, an electromagnetic induction heating cooker according to the present invention has a container for accommodating food, a non-metallic inner frame for accommodating the container, and A non-metallic coil base disposed outside the inner frame, and a coil mounted on an outer surface of the coil base and inductively heating the container while being opposed to a bottom portion and a lower side surface of the container, A first gap was provided between the container and the inner frame, a second gap was provided between the inner frame and the coil base, and the first gap and the second gap were opposed to the coil. Things.

[0008]

In the electromagnetic induction heating type cooker according to the present invention, the coil is mounted on the outer surface of the coil base provided outside the inner frame. Therefore, in manufacturing, the coil is directly wound around the outer surface of the coil base and formed. In addition to the above, the coil base may be smaller than the inner frame, so that the manufacturing advantage is great. In use, the container accommodated in the nonmetallic inner frame is heated by electromagnetic induction of the coil on the outer surface of the nonmetallic coil base, and the food contained in this container is heated. Also, by the first gap between the container and the inner frame and the second gap between the inner frame and the coil base,
High heat retention effect can be obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an electromagnetic induction heating type cooker according to the present invention will be described with reference to the drawings. Although the cooker of this embodiment is a rice cooker, FIG.
In the figure, reference numeral 1 denotes a vessel main body, which is composed of a bottomed cylindrical inner frame 2 having an open upper surface, and an outer frame 3 having the inner frame 2 therein and forming an outer shell of the vessel main body 1. I have. Inner frame 2
Is made of plastic such as FR-PET resin which is a non-metallic material, and is formed by injection molding or the like into a shape substantially similar to the outer shape of the pan 4 which is a container which is removably accommodated in the inner frame 2. ing. The outer frame 3 is also a molded plastic product. The pot 4 is formed of a bottomed cylinder having an upper surface opened mainly of an aluminum material. And hot pot 4
Is supported by the flange portion 5 formed at the upper end thereof resting on the upper end surface of the inner frame 2, with a predetermined first gap between the inner frame 2 and the pot 4 housed therein. A certain first space 6 is formed. A heating layer 7 made of a magnetic metal material for heating the pan 4 is provided on the outer surface of the pan 4.

Reference numeral 11 denotes a coil base.
Is made of a self-extinguishing plastic mainly composed of FR-PET resin, which is a nonmetallic material, and is formed by injection molding or the like into a shape similar to the peripheral shape from the bottom of the inner frame 2 to the lower part of the outer periphery. I have. And coil base 11
Is attached to a lower side of a coil base attachment portion 12 which is vertically provided from an upper surface portion of the outer frame 3. The coil base 11 is located outside the lower portion of the inner frame 2, and a second space 13 as a predetermined second gap is formed between the coil base 11 and the inner frame 2. A coil 14, which is located at a predetermined distance from the heating layer 7 of the pan 4 and is heated by electromagnetic induction, is mounted on the convex outer surface, that is, the lower surface of the coil base 11. This coil 14 is spirally wound concentrically with the center of the coil base 11, and
The bottom of the pot 4 and the lower portion of the side face thereof are opposed to each other with the coil base 11, the second space 13, the inner frame 2 and the first space 6 interposed therebetween. Further, a farite core base 15 that covers the coil 14 from the outside so as not to be exposed is attached to the coil base 11. This farite core base 15
It is made of self-extinguishing plastic mainly composed of R-PET resin or the like. A plurality of ferrite cores 16 are provided outside the farite core base 15 in a direction perpendicular to the winding direction of the coil 14. The ferrite core 16 is obtained by sintering a material having high magnetic permeability using iron oxide as a main raw material. Further, a magnetic shield 17 made of aluminum material and preventing leakage of magnetic flux is provided to face the outer surface of the coil 14.

A body heater 21 composed of a cord heater or the like for keeping the inner frame 2 warm is provided above the outer surface of the inner frame 2. Also, in the lower part of the inner frame 2,
A thermal fuse 22 is provided. Further, a pot sensor having a heat-sensitive part formed of a negative temperature coefficient thermistor for detecting the outer surface temperature of the pot 4 is provided above the center of the coil base 11.
23 is provided to be movable up and down. This pot sensor 23
It is urged upward by a spring 24 which is an elastic member, and penetrates through the bottom of the inner frame 2 and projects upward to contact the bottom surface of the pan 4. Also a pan sensor
A switch lever 25 fixed to 23 penetrates through the coil base 11 and protrudes downward.

A control board is provided at a lower portion in the main body 1.
26 are provided. The control board 26 includes the coil 14
And an inverter circuit for supplying a predetermined high-frequency current to the power supply. The control board 26 includes the switch lever
A pan switch 28 having an opening / closing element 27 operated by 25 and detecting the presence or absence of the pan 4 is also provided. That is, when the pot 4 is not stored in the inner frame 2, the switch lever 25, which is pushed by the spring 24 and rises together with the pan sensor 23, lifts the opening / closing member 27. 4, the pan sensor 23 and the switch lever 25 are pushed down, and the switch 27 is also lowered. Thereby, the presence or absence of the pan 4 is detected.

On the other hand, a space 31 is formed between the inner frame 2 and the outer frame 3 at a rear portion in the main body 1, and a heating control board 32 is disposed in the space 31. This heating control board 32 includes
The amount of heating of the pan 4 by the coil 14 is adjusted, and the switching element such as the inverter circuit or the IGBT element described above is used.
A control circuit for controlling 33 is provided. Further, the switching element 33 constitutes a circuit breaker driving means for driving the circuit breaker of the high-frequency current of the coil 14, and is provided below the heating control board 32 as a heat-generating component that generates heat when the coil 14 is driven. And a radiator 34 is attached.
Further, an exhaust port 35 is provided above the heating control board 32 on the upper rear surface of the outer frame 3.
An intake port 36 is provided below and below the heating control board 32 at the bottom and bottom of the rear surface. Further, the outer frame 3
At the bottom front of the is a cord reel that winds the power cord 37
38 are provided.

Reference numeral 41 denotes a lid that covers the upper opening of the pot 4 so that it can be opened and closed. The lid 41 is attached to the outer lid 42 made of, for example, a polypropylene resin, an outer lid cover 43 provided along the lower outer periphery of the outer lid 42, and forming a space below the outer lid 42. And a radiating plate 44 made of an aluminum member. Further, an inner lid 45 for closing the upper opening of the pan 4 is detachably provided below the radiating plate 44 via an inner lid retainer 46. . 47 is the outer lid cover 43
And a heat sink 44 between which an annular lid packing is held. When the lid 41 is closed, the lower end of the lid packing 47 comes into close contact with the flange portion 5 of the pan 4. A clamp button 48 is provided on the front side of the lid 41, and by pressing this clamp button 48, the lid 41 can be opened around a hinge 49 provided on the rear side of the lid 41 as a center of rotation. . On the other hand, on the upper surface of the heat sink 44 forming the lower surface of the lid 41,
As a lid heating means for heating the radiator plate 44 during cooking and keeping the temperature, a lid heater 51 such as a cord heater is provided. On the upper surface of the heat radiating plate 44, a lid sensor 52 composed of a negative temperature coefficient thermistor is provided as a lid temperature detecting means for detecting the temperature of the heat radiating plate 44. The lid heater 51 forms a parallel circuit with the body heater 21 of the inner frame 2. Reference numeral 53 denotes a steam port for discharging steam from the pan 4 to the outside, and reference numeral 54 denotes an operation panel provided on an upper portion of the outer lid 42.

Next, the circuit configuration of the rice cooker will be described with reference to FIG. In the figure, reference numeral 61 denotes a microcomputer, which is a well-known device, in addition to a control device 62 and an arithmetic device 63 which constitute a microprocessor, a clock device 64.
And a storage device 65 including a ROM and a RAM. The input side of the microcomputer 61 has an A / D
An input device 66 comprising a converter is connected, and the input device 66
, An operation switch 67 as an operation means provided on the operation panel 54 and a power failure detection circuit 68 are connected together with the pan sensor 23, the lid sensor 52, and the pan switch 28 described above.
On the other hand, an output device 71 is connected to the output side of the microcomputer 61. Via the output device 71, the induction heating means 72 for electromagnetically heating the pan 4 and the body heater 21 and the lid heater 51 are simultaneously operated. A heater driving means 73 having a switch means such as a triac for controlling power cutoff is connected. In addition to these, the output device 71 has LED display means 74 for displaying operating states such as rice cooking and heat retention, and display driving means 76 and 77 for controlling display on an LCD display means 75 as a liquid crystal display for displaying time and the like. Is connected, and a buzzer driving means 79 for controlling the sound of a buzzer 78 for notifying the end of the rice cooking is connected. The microcomputer 61 includes an operation signal of an operation switch 67 for starting rice cooking and heat retention, and the like,
The temperature data from the pan sensor 23 and the lid sensor 52 and the pan detection signal from the pan switch 28 are used as input information, and in addition to this input information, time information from a timer 64 is set in the storage device 65 in advance. According to the control sequence, the induction heating means 72, the lid heater 51 and the body heater 21,
The LED display means 74, the LCD display means 75, and the buzzer 78 are controlled. Reference numeral 81 denotes a power failure backup means connected to the output device 71, which retains the contents stored in the storage device 65 of the microcomputer 61 by the microcomputer drive circuit 82 at the time of power failure.

The induction heating means 72 includes a high-frequency current generator 83 for supplying a predetermined high-frequency current based on an output signal from the microcomputer 61, and controls the power supply to the coil 14 while varying the high-frequency current value. The output adjustment circuit 84 is provided. Then, an alternating magnetic field is generated in the coil 14, and an eddy current is generated in the heating layer 7 of the pot 4 in the magnetic field, and the eddy current is converted into Joule heat, so that the heating layer 7 generates heat. The pot 4 is heated.

The control temperature of the pot sensor 23 during cooking and keeping the temperature is controlled within a temperature range of -10 ° C to 130 ° C.
For example, the temperature of the rice cooker before rice cooking, which promotes the absorption of rice as cooked food, is controlled at 45 ° C to 70 ° C, the temperature at which rice heating is stopped, and the temperature at which it shifts to spots is 120 ° C, and the heat retention temperature is 65 ° C. ~
Bring to 72 ° C. Further, the control temperature of the lid sensor 52 during cooking and keeping the temperature is controlled within a temperature range of −10 ° C. to 120 ° C.
For example, the temperature is set to 110 ° C during spotting, and to 69 ° C to 76 ° C during warming. These temperature controls have the same configuration as a conventional rice cooker.

Next, a method of assembling the coil 14 will be described. The coil 14 is spirally wound directly around the convex outer surface of the coil base 11. After this winding, a predetermined current is applied to the coil 14 to check whether the sheath of the wire of the coil 14 is damaged or deteriorated, and the coil 14 is connected to the coil base by heat fusion due to heat generation of the wire. Temporarily fix to 11. Next, a ferrite core base outside the coil 14
15 is attached, and the coil 14 is fixed to the coil base 11.
Next, the ferrite core 16 is mounted on the outer surface of the ferrite core base 15. Thus, the coil 14 is placed on the coil base 11.
And a coil base assembly (sub-assembly) incorporating the ferrite core 16 can be performed. And when assembling the container body 1,
The previously prepared coil base assembly is incorporated into the container body 1 provided with the inner frame 2.

As described above, by attaching the coil 14 to the convex outer surface of the coil base 11, the coil base 11 itself can be guided and the coil 14 can be directly wound around the coil base 11. Only this winding operation can be performed. Thereby, the coil 14 can be formed into a predetermined shape. Therefore,
Good workability. On the other hand, if the coil is to be mounted on the concave inner surface of the coil base, the coil must be wound and formed, and then mounted on the coil base, which requires a two-step process, resulting in poor workability.

Further, the coil base 11 used for winding the coil 14 has almost no portion to which the coil 14 is mounted, has no extra members in the winding operation, and is smaller than the inner frame 2. An extra member does not interfere, and the work is easy. At the same time, the coil base 11 smaller than the inner frame 2 is not bulky, has good transportability, and is used when storing parts such as the coil base 11 before winding the coil 14 or the coil base assembly after winding. It also takes up minimal space and takes up little space. In addition, when assembling the container body 1, the coil base assembly previously assembled in another process is a simple operation of assembling into the container body 1, so that the coil 14 and the ferrite core 16 can be incorporated in a short time. Thus, the assembling operation is simplified, and the manufacturability is improved.

When the coil 14 is to be replaced because the coil 14 has been damaged, a coil base assembly may be supplied as a replacement part, whereby the coil is mounted on the inner frame at a service factory. There is no need for
Since disassembly is a simple operation of simply removing the coil base assembly, service repairability is improved.

Next, the operation at the time of use will be described.
When the pot 4 containing the rice and water to be cooked is accommodated in the inner frame 2 and the operation switch 67 is operated to start cooking rice, a predetermined heating pattern is set based on the control sequence stored in the storage device 65. To start heating the food. In other words, based on the temperature information from the pot sensor 23 and the lid sensor 52, a rice cooking process for promoting water absorption of rice, a rice cooking process for boiling water in the pot 4 by strong heating to gelatinize rice, and a rice cooking process. When the temperature of the bottom of the pan 4 reaches 120 ° C., the cooking process determines that the cooking is finished and makes it uneven, and the unevenness in which the inside of the pan 4 is kept at a high temperature to completely promote the viscosity. The cooking process is performed sequentially, and rice is cooked. After the swing process, the process shifts to the warming process.

In the process of cooking rice and keeping heat, there is a first space 6 between the pot 4 and the inner frame 2 and a second space 13 between the inner frame 2 and the coil base 11. In addition, since these form a two-layer heat insulating space outside the pan 4, the heat retaining effect of the pan 4 is enhanced. Therefore, the heating efficiency at the time of cooking rice and keeping heat is improved.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made. For example,
In the above embodiment, the rice cooker has been described as an example, but the present invention can be applied to an electromagnetic induction heating type cooker other than the rice cooker.

[0025]

According to the present invention, in an electromagnetic induction heating type cooker in which a container to be induction-heated by a coil is accommodated in an inner frame, a coil is provided on an outer surface of a coil base provided outside the inner frame. Since the coil is mounted, the coil can be easily mounted, and the manufacturability can be improved. In addition, since the first gap is provided between the container and the inner frame and the second gap is provided between the inner frame and the coil base, the heat retaining effect is enhanced, and the heating during heating or during the heat retaining is performed. Efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of an electromagnetic induction heating type cooking device of the present invention.

FIG. 2 is a block diagram showing an electrical configuration of the same.

[Explanation of symbols]

 2 inner frame 4 pot (container) 6 first space (first gap) 11 coil base 13 second space (second gap) 14 coil

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) A47J 27/00 103

Claims (1)

(57) [Claims] 1. A container for storing food, a non-metallic inner frame for storing the container, a non-metallic coil base disposed outside the inner frame, a bottom portion of the container, A coil mounted on the outer surface of the coil base to face the lower part of the side surface for induction heating the container, providing a first gap between the container and the inner frame, and the inner frame and the coil base; A second gap is provided between the coils, and the first gap and the second gap are opposed to the coil.