JPH10201617A - Electromagnetic induction heating type rice cooking heat retaining pan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the heat retaining property of a pan with a simple structure without using a warming heater by providing one heating means for heating a pan commonly in rice cooking and warming, and forming a heat insulating layer on the outer surface of the pan. SOLUTION: A pan body 1 is formed of an outer frame 2 and a bottomed cylindrical inner frame 3 provided on the inside thereof, and a pan 5 is housed in a pan housing part 4 constituted by the inner frame 3 in such a manner as to be attachable and detachable. A support projection is annularly protruded on the upper part of the inner frame 3, and a flange 7 is formed on the upper part of the pan 5, so that the pan 5 is stably supported by placing the flange 7 on the support projection 6. The pan 6 is formed of a pan body 8 consisting of a material mainly composed of aluminum and a heat-generating layer 9 consisting of a magnetic metallic material such as ferrite stainless steel which is bonded to the outer surface of the part extending from the bottom surface of the pan body 8 to the side surface lower part, and a heat insulating layer 10 by a plastic coating film mainly composed of silicone resin is formed on the outer surface of the pan 5 in order to enhance the heat insulating property by heat insulating effect.

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 rice cooker for cooking rice by heating rice and water contained in a pot by electromagnetic induction.

[0002]

2. Description of the Related Art An electromagnetic induction heating type rice cooker has a pot heated by induction heating using an electromagnetic coil during rice cooking. In the conventional rice cooker, a cord-shaped heat insulator is provided on the outer surface of the pot accommodating portion for accommodating the pot, corresponding to a portion of the side of the pot from a substantially middle portion to an upper portion.

At the time of keeping the temperature after cooking rice, the pot is heated by induction heating by an electromagnetic coil, and the side of the pot is further heated by the above-mentioned heater to keep the temperature.
In addition, the output of induction heating by the electromagnetic coil at the time of heat retention is suppressed to be lower than that of rice cooked.

[0004] The reason for heating the side of the pot at the time of heat retention is that in the case of the electromagnetic induction heating type, the pot itself generates heat, so that it is compared with the heater type in which the pot is heated by the radiant heat of the heater to cook rice. , The temperature around the pot does not rise much,
Therefore, the heat retention of the pot at the time of heat retention is low, and in order to supplement this heat retention, the side of the pot is heated by a heat retention heater.

[0005] Further, conventionally, in order to increase the heating efficiency of the pot by the heat retaining heater, a frame member constituting the pot accommodating portion is formed of a metal material such as stainless steel having a high heat radiation efficiency.

[0006]

However, if a heat retaining heater is used or the pot housing is made of a metal material such as stainless steel having a high heat radiation efficiency, the structure becomes complicated and the productivity is reduced. .

The present invention has been made in view of such a point, and an object of the present invention is to provide an electromagnetic induction heating system capable of enhancing the heat insulation of a pot with a simple configuration without using a heat insulation heater. It is to provide a rice cooker.

[0008]

According to the present invention, in order to achieve the above object, a heat insulating layer is formed on an outer surface of a pan, or a heat insulating layer is formed on an outer surface of a pan, and a heat insulating layer is formed in a pan housing portion. The pot is made of a highly heat-resistant material to enhance the heat insulation of the pot, and the heating of the pot at the time of cooking and keeping the temperature is shared and executed by one heating means.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In the figure, reference numeral 1 denotes a pot main body, which comprises an outer frame 2 and a bottomed cylindrical inner frame 3 provided inside the outer frame 2, and the inner frame 3 constitutes a pot accommodating portion 4. The pan 5 is housed in the pan housing 4 so as to be freely inserted and removed.

A support projection 6 is formed on the upper part of the inner frame 3 in a ring shape, and a flange 7 is formed on the upper part of the pot 5 so as to be bent outward. , Whereby the pot 5 is stably supported.

The pot 5 is composed of a pot body 8 made of a material mainly composed of aluminum having excellent heat conductivity,
Heating layer 9 made of a magnetic metal material such as ferritic stainless steel joined to the outer surface of a portion extending from the bottom surface to the lower side surface of
It is composed of

On the outer surface of the pot 5, a heat insulating layer 10 made of a plastic coating film mainly composed of silicone resin or polyether sulfone resin of about 50 to 100 μm is provided in order to enhance the heat insulation of the pot 5 by the heat insulating effect. Is formed. The heat insulating layer 10 of the plastic coating film has a thickness of 50 μm or more because the heat insulating effect increases as the film thickness increases, and the coating material is preferably alumina powder, titania powder, aluminum powder, glass powder, or the like. By mixing inorganic materials having low thermal conductivity such as hollow glass beads, glass fibers, and mica powder, it is possible to further improve the heat insulating property and to store the heat of the pot 5 to bring out the effect of increasing the heat retaining property. is there.

In order to enhance the heat insulating effect of the heat insulating layer 10, a method of increasing the film thickness to about 100 to 200 μm or providing a plastic cover on the heat insulating layer 10 to cover the film surface is used. It is also possible to take.

A pot temperature sensor 12 elastically abuts and contacts substantially the center of the outer bottom surface of the pot 5, and the pot temperature sensor 12 detects the pot temperature sequentially. On the outer surface of the inner frame 3, as a heating means, an electromagnetic coil 13 formed by spirally winding a litz wire obtained by gathering and twisting a copper wire insulated with a resin such as polyurethane is used as a heating layer of the pan 5. 9 are provided.

The electromagnetic coil 13 is inserted into a coil base 14 made of a resin material such as polyethylene terephthalate reinforced with glass fiber. That is, when the coil base 14 is formed,
Is molded and integrated therein. The electromagnetic coil 13 is fixed to the inner frame 3 together with the coil base 14 simply by screwing the coil base 14 to the inner frame 3.

The inner frame 3 which constitutes the pan accommodating portion 4 has an upper wall 3a.
And the lower wall 3b. The upper wall 3a and the lower wall 3b are formed of a resin material having a higher heat insulating property than a metal material in order to enhance the heat retention of the pot 5. For example, the upper wall 3a is formed integrally with the outer frame 2 by a resin material such as polypropylene, and the lower wall 3b is formed by a resin material such as polyethylene terephthalate resin reinforced with glass fiber or polyamide resin reinforced with glass fiber. I have. The inner frame 3 has a thickness of about 1.0 to 4.0 mm in order to further enhance the heat retaining property of the pot 5. In addition,
In order to further enhance the heat insulation of the inner frame 3, an inner frame cover may be provided on the outer surface of the inner frame 3 with a gap of about 1 to 10 mm.

A heating control board 17 is provided on the inner bottom of the kettle body 1.
The heating control board 17 includes a control circuit 18 such as an inverter circuit for supplying a high-frequency current of 24 to 30 KHz to the electromagnetic coil 13 and a switching element 19 such as an IGBT transistor. Are connected, and the heat generated by the heat generated by the switching element 19 is radiated through the radiator 20.

The heating control board 17 has a board temperature sensor 2
1 is provided to detect the temperature inside the main body. The substrate temperature sensor 21 is preferably attached to a high-temperature heating component such as the switching element 19 on the heating control substrate 17 or its vicinity, or to the radiator 20 or its vicinity. By providing the substrate temperature sensor 21 on the heating control substrate 17, there is an advantage that wiring processing is unnecessary and the structure is simplified.

An operation board 22 is provided inside the shuttle body 1, and an operation panel 23 is provided on the operation board 22, and the operation panel 22 is exposed to the outside from the side surface of the outer frame 2.

A lid 25 is provided on the upper part of the shuttle body 1.
The lid 25 includes an outer lid 26, an outer lid cover 27, and an inner lid 28 constituting a lower surface member of the lid 25. Outer lid 2
6 and the outer cover 27 are each made of a resin such as polypropylene. The outer lid cover 27 is attached to the lower peripheral edge of the outer lid 26. The inner lid 28 is made of metal such as aluminum or stainless steel, and the outer lid cover 27
It is attached to the lower surface side of the outer lid 26 inside.

A flange 29 projecting substantially horizontally is formed inside the outer cover 27, and a certain gap 30 is provided between the flange 29 and the outer cover 26.
The peripheral portion of the inner lid 28 is inserted therein, and the inner lid 28 can be displaced up and down through the gap 30. A packing 31 formed of an elastic member such as silicone rubber is provided between a peripheral portion of the inner lid 28 and the outer lid 26, and the packing 31 seals between the inner lid 28 and the outer lid 26. ing.

A plurality of steam holes 34 are formed in the center of the inner cover 28, and a steam discharge port 35 is formed in the outer cover 26 corresponding to the steam holes 34, and the steam discharge port 35 and the inner cover 28 are formed.
A packing 36 formed of an elastic member such as silicone rubber is provided between the inner cover 28 and the steam hole 34 of the inner cover 28 through the inside of the packing 36.
Is in communication with A guide member 37 for guiding the flow of steam is provided in the steam discharge port 35.

A spring 40 is provided between the inner lid 28 and the outer lid 26, and the inner lid 28 is elastically urged downward by the elastic force of the packings 31, 36 and the elastic force of the spring 40. ing. A lid heater 41 for heating the inner lid 28 and an inner lid 28
Is provided with a lid temperature sensor 42 for sequentially detecting the temperature of the lid.

As shown in FIG. 2, the lid 25 is attached to the upper part of the shuttle body 1 via a hinge mechanism 45 so as to be rotatable in the vertical direction. The lid 28 opens and closes the opening of the pot 5. When the lid 25 is closed on the upper surface of the pot body 1, the lower surface of the peripheral portion of the inner lid 28 is attached to the upper surface of the upper peripheral edge of the pot 5.
The elastic force of the spring 1 and 36 and the spring 40 abut on each other. The spring 40 is not always necessary and may be omitted.

On the opposite side of the hinge mechanism 45,
A clamp mechanism 46 for retaining the lid 25 in a closed state by removably locking the lid 25 to the shuttle main body 1 is provided, and a spring 47 is provided at a portion where the hinge mechanism 45 is provided. The lid 25 is always elastically urged in the opening direction by a spring 47, and the urging force causes the
Is released, the lid 25 automatically pivots upward and opens.

To explain the rice cooking process, water and rice are stored in the pot 5 and the water in the pot 5 is heated to 60 ° C. by induction heating (IH heating) based on the electromagnetic coil 13 as shown in FIG.
The rice is cooked for about 15 minutes by heating to the following temperature to promote water absorption to rice. After the completion of the overcooking, the process shifts to boiling heating. It should be noted that hot-boiled cooking is not always necessary and may be omitted.

The boiling heating is a process of boiling the water in the pot 5 and is an important point for ensuring rice cooking performance. In particular, heating from about 60 ° C. or higher, which is the gelatinization temperature of rice, to boiling is important. If the heating is insufficient during this time, the rice becomes hard, and in some cases, the core remains on the rice due to insufficient heating. Therefore, conventionally, boiling heating is performed with the maximum heating amount of the rated power consumption.

In the present embodiment, the output of induction heating (IH heating) of the pot 5 is 1300 W, 1000 W, 700 W, 400 W
It is divided into four stages of W, and 700 W is used for side cooking and heating is performed by continuous energization of 1300 W for boiling heating.

During boiling heating, the lid temperature sensor 42
When the temperature becomes equal to or higher than ℃ and stabilized at a predetermined temperature, the process shifts to boiling continuous heating. This boiling continuous heating has a heating output of 1000
It is controlled to reduce to W and switch to a predetermined intermittent energization so that the water in the pot 5 continues to boil for about 1 to 7 minutes.

When a predetermined stroke time elapses or when the temperature of the pot temperature sensor 12 rises by 2 to 5 ° C.
Move to the cooking process. This cooking process is 1300W
And the temperature of the pan temperature sensor 12 is 10 to 15
The process ends when the temperature rises by ° C., and after this process, the process shifts to the swing process. This spotting process is a pot temperature sensor 1 with 700W
The pot 5 is heated in accordance with the temperature of 2, and the inside of the pan 5 is maintained at a high temperature to the extent that no scorching occurs, thereby securing the spotting effect. Then, after this spotting process, the process shifts to a warming process.

In the warming process, the power consumption of the electromagnetic coil 13 is reduced to 400 W, and the pot 5 is heated by intermittent energization. For example, based on a cycle of energization for 1 second and power cut for 7 seconds, if the temperature of the pan 5 is 70 ° C. or higher, power supply for 1 second is omitted, power cut for 7 seconds is continued, and power cut for 7 seconds is performed. When the temperature of the pan 5 is lower than 70 ° C. at the elapse of time, heating is performed by energizing for 1 second, and the pan 5 is maintained at a temperature of 70 to 76 ° C. In addition, the heat retention temperature of the pan 5 is 70-76 degreeC.
In addition to this, the temperature may be switched between two types, that is, the temperature range and 64-70 ° C., or a function of temporarily reheating the temperature of the rice to 80 ° C. or more may be added. However, in any case, as the heat retaining means of the pot 5, the electromagnetic coil 13 as a heating means for heating the pot 5 during cooking is shared and used.

During rice cooking and heat retention, the lid heater 41 heats the inner lid 28 of the lid 25, and this heating reduces the condensation on the lower surface of the inner lid 28.
When you open 5, the soup does not run off in large quantities.

When the lid 25 is closed, a small gap is formed in the contact portion between the lower surface of the peripheral edge of the inner lid 28 and the upper surface of the upper peripheral edge of the pot 5 such that steam leaks partially. Since the upper peripheral edge of the pot 5 is elastically pressed by the urging force of the packings 31, 36 and the spring 40, the gap is kept as a small and uniform gap. The soup due to the condensation of steam during rice cooking enters the gap to form a water film, and the water sealing effect of the water film ensures that the lower surface of the peripheral portion of the inner lid 28 and the upper surface of the upper peripheral portion of the pot 5 are securely formed. And the steam in the pan 5 does not leak from between the inner lid 28 and the pan 5. Therefore, it is possible to prevent the rice cooker heating performance from being reduced due to the steam leak and to prevent the pot body 1 from being stained due to the steam leak.

The inner lid 28 can be elastically displaced up and down via the packings 31 and 36 and the spring 40. Therefore, even if the height of the pot 5 varies, the inner lid 28 can be elastically displaced up and down. The state of contact between the lower surface of the peripheral edge of the inner lid 28 and the upper surface of the upper peripheral edge of the pot is always kept uniform, so that a water sealing effect for the gap between the contact portions is reliably obtained. In addition, due to the vertical elastic displacement of the inner lid 28, the clamp mechanism 46 always keeps a constant relationship between the lid 25 and the shuttle main body 1 when the lid 25 is closed.
Locking of the lid 25 can always be accurately achieved.

At the time of cooking rice, the steam in the pot 5 is positively discharged to the outside through the steam hole 34 and the guide member 37. Therefore, the internal pressure in the pot 5 does not increase so much that the water sealing effect is not adversely affected.
If the steam hole 34 is clogged with rice grains or the like and the internal pressure in the pot 5 rises abnormally, the pressure in the pot 5 causes the inner lid 28 to pack the packings 31 and 36 and the spring 40.
Is displaced upward against the elastic force of the above, and this displacement creates a sufficient gap between the inner lid 28 and the upper peripheral edge of the pot 5, and steam flows out from this gap to ensure safety.

At the time of induction heating by the electromagnetic coil 13, the heat generating layer 9 of the pan 5 generates heat, and the heat generated by the heat is transmitted to the pan main body 8 formed of a material having excellent heat conductivity, and the whole of the pan main body 8 is heated. Is done. A heat insulating layer 10 made of a plastic coating film is formed on the outer surface of the pot 5, so that the heat conducted to the pot body 8 is prevented from radiating to the outside by the heat insulating layer 10. Is improved.

This eliminates the need for a heater for keeping the temperature of the side of the pot 5 warm. In addition, since the pot housing portion 4 constituted by the inner frame 3 is formed of a material having a high heat insulating property, the heat radiated from the pot 5 stays between the pot 5 and the pot housing portion 4, Radiation from the storage portion 4 to the outside is suppressed, and thus the heat retention of the pot 5 is further improved.

As described above, a heat retaining heater is not required, and it is not necessary to use a metal material for the pot accommodating portion 4 in order to easily radiate the heat of the heat retaining heater to the pot 5, so that the structure is simple. Become

In addition, when cooking rice, since the heat insulating layer 10 is formed on the outer surface of the pot 5, the heat of the heat generating layer 9 effectively acts on heating the water in the pot 5, thereby improving the heating efficiency.
Thereby, it is possible to cook delicious rice with less uneven cooking by suppressing uneven heating.

Further, since a heat retaining heater for heating the side surface of the pot 5 is not required, the power is not required, and power saving can be realized. In addition, since the heat insulating layer 10 is formed on the outer surface of the pot 5, the outer surface of the pot 5 is less likely to become hot. Therefore, the heat is stopped during the heat holding, and the pot 5 is taken out while holding the flange 7 of the pot 5 by hand. In this case, there is an advantage that the pot 5 can be easily held.

At the time of cooking rice and keeping warm, heat radiation to the outside of the pot housing 4 is suppressed, and no heat keeping heater is attached to the outer surface of the pot housing 4, so that the pot housing 4 is The temperature rise in the space between the frame 2 is suppressed, so that the excessive temperature of the electrical components such as the heating control board 17 and the operation board 22 disposed in the space between the pan housing 4 and the outer frame 2. It is possible to prevent the electrical components from deteriorating or failing for a long time by suppressing the rise.

[0042]

As described above, according to the present invention, it is possible to enhance the heat insulation of the pot without using a heat insulation heater and without using a metal material in the pot accommodating portion. In addition, power consumption can be reduced. In addition, the heating efficiency at the time of cooking rice can be enhanced, delicious rice with less uneven cooking can be cooked, and power consumption can be suppressed low. In addition, the usability can be improved by keeping the outer surface temperature of the pot low, and furthermore, the temperature rise in the space between the pot housing and the outer frame is suppressed, and the electrical components placed in that space deteriorate or fail. Can be prevented over a long period of time.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a rice cooker according to an embodiment of the present invention as viewed from the front.

FIG. 2 is a side view of the rice cooker.

FIG. 3 is a graph showing a rice cooking process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Hook main body 2 ... Outer frame 3 ... Inner frame 4 ... Pan accommodation part 5 ... Pan 10 ... Heat insulation layer 13 ... Electromagnetic coil

Claims (2)

[Claims] 1. An electromagnetic induction heating rice cooker comprising: a single heating means for heating a rice pan in common during cooking and warming; and a heat insulating layer formed on an outer surface of the pan. 2. A pot is provided with one heating means for heating the rice in common during cooking and keeping the heat, wherein the pot accommodating portion for accommodating the pan is formed of a material having high heat insulating properties, and the heat insulating layer is provided on the outer surface of the pan. An electromagnetic induction heating type rice cooker, characterized by forming a rice cooker.