JPH09140570A - Electric rice cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide uniform heating and strong convention at the time of cooking rice. SOLUTION: This rice cooker has a vessel body formed to be capable of internally setting an inner pot 3, and a lid body capable of covering the upper opening of the vessel body for the release and closure of the opening. Also, the inner bottom of the inner pot 3 is provided with a heating means 10 for applying heat to the inner pot 3. In this case, many surface area increasing parts (e.g. small projections 50 and so forth) are formed on the inner bottom of the inner pot 3 for increasing the heat transfer area thereof at a rice cooking process, thereby ensuring uniform heating and providing strong convection via the generation of many small bubbles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric rice cooker, and more particularly to an electric rice cooker having an improved inner pan heating efficiency.

[0002]

2. Description of the Related Art In a general electric rice cooker, rice is cooked by heating an inner pot containing rice and water by a heating means arranged below the inner pot.

In the case of using a hot plate type electric heater as the heating means, the inner pot is heated by transmitting the heat generated by the electric heater to the bottom of the inner pot, and the work is used as the heating means. In the case of using a coil (in other words, an electromagnetic induction coil), magnetic flux generated by the work coil is used to generate an eddy current at the bottom of the inner pot to heat the inner pot.

[0004]

However, in the electric rice cooker having the above-mentioned structure, the temperature of the bottom portion of the inner pot (that is, the portion corresponding to the electric heater or the work coil) is different from the temperature of other portions during rice cooking. Since it becomes higher inevitably, there is a problem that it is difficult to uniformly heat the rice contained in the inner pot. In addition, since bubbles generated at the bottom of the inner pot during boiling tend to grow while moving along the inner peripheral surface of the inner pot, only large bubbles are less likely to be generated and strong convection is less likely to occur. Then, there is also a problem that it is difficult to obtain a good cooked state because the rice is not easily stirred during cooking.

The present invention has been made in view of the above points, and an object thereof is to obtain uniform heating and strong convection during rice cooking.

[0006]

According to the basic constitution of the present invention, as means for solving the above-mentioned problems, a container main body configured so that an inner pan can be set therein and an upper opening of the container main body are provided. An electric rice cooker comprising a lid body that can be opened and closed so as to cover the inner bottom portion of the container body, and a heating means for heating the inner pot. The portion is formed so that, when cooking rice, uniform heating can be obtained by increasing the heat transfer area at the inner bottom portion, and strong convection can be obtained by the generation of many small bubbles.

In the basic structure of the present invention, when the surface area increasing portion is formed in a portion corresponding to the heating means for heating the inner pot, the surface area increasing portion may be formed in the minimum necessary amount, which is cost effective. It is advantageous in that

Further, when the surface area increasing portion is not formed at the portion where the temperature detecting means is brought into contact, the close contact between the temperature detecting means and the inner pot is not impaired, and accurate temperature detection is possible. It is preferable because it can be performed.

Further, it is preferable that the surface area increasing portion is formed as a small projection or a small concave portion integrally formed in order to efficiently wash rice, and in that case, if the forming interval of the surface area increasing portion is made larger than the rice grain. It is preferable that the small protrusions and the rice come into efficient contact with each other during rice washing, and the rice washing becomes easier. .

Further, when the surface area increasing portion has a predetermined size and is continuous and is a convex portion which causes a small convection on the inner surface side during heating, the surface is increased by the small convection generated on the inner surface side of the convex portion. It is preferable in that the efficiency is significantly increased. .

Further, when the film thickness of the fluororesin coating layer in the area where the surface area increasing portion is formed is made larger than the other portions, uniform heating during rice cooking is promoted and burning of cooked rice can be prevented. .

Further, when the color tone of the fluororesin coating layer is made different between the surface area increasing portion forming region and other portions, it is preferable in that the amount of cooked rice is clarified.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

First, the structures of two types of electric rice cookers according to the present invention will be described.

FIG. 1 shows an electric rice cooker using an electromagnetic induction coil (hereinafter referred to as a work coil) as a heating means.

This electric rice cooker has a double-structured container body 1 which is constructed so that an inner pot 3 can be set therein and has a space 4, and an upper opening of the container body 1 is openably and closably covered. And a lid 2.

The container body 1 has a body portion 5a serving as an outer wall.
An outer case 5 having a substantially inverted L-shaped cross section made of an integrally molded product of a synthetic resin (for example, polypropylene) having an upper wall and a shoulder 5b serving as an upper wall, and an upper end connected to an inner peripheral edge of the shoulder 5b. A cylindrical inner case 6 with a bottom made of a synthetic resin (for example, made of polypropylene), and a dish-like made of a synthetic resin (for example, made of polypropylene) whose upper end is joined to the lower end of the body 5a of the outer case 5 , And the space 4 is formed by being surrounded by the outer case 5, the inner case 6, and the bottom member 7. Note that the inner pan 3 is set in the inner case 6 so as to be removable.

A sensor hole 9 is formed at the center of the bottom surface of the inner case 6 so as to face the center sensor 8 which functions as a temperature detecting means. The sensor hole 9 surrounds the sensor hole 9 and functions as a heating means. An annular work coil 10 is disposed on the bottom surface of the inner case 6 and a curved portion between the bottom surface and the side peripheral surface.

The inner pot 3 is of a round bottom type in which the radius of curvature of the curved portion 3b from the bottom portion 3a to the side peripheral portion 3c is large, and the work coil 10 has the bottom portion 3a and the curved portion 3b of the inner pot 3. It is arranged corresponding to.

The work coil 10 corresponds to the inner case 6
Is sandwiched between a ferrite core 12 fixed to the bottom surface of the inner casing 6 with a screw 11 and the bottom surface of the inner case 6, and the ferrite core 12 is used for a device in which the magnetism of the electromagnetic induction coil 10 exists below. It also acts as a shield so as not to affect it. A center sensor 8 is provided in the sensor hole 9 and is in contact with the bottom of the inner pot 3. A heat retaining heater 13 is attached to the side peripheral surface of the inner case 6. Further, a cylindrical partition wall 14 is vertically provided from the lower surface of the outer case shoulder portion 5b, and a heat insulating material 15 is disposed between the partition wall 14 and the inner case 6.

Below the ferrite core 12, a heat shield plate 16 is supported, and a cooling fan 17 is arranged on the heat shield plate 16. The cooling fan 17 sends cooling air under pressure to a power transistor and a rectifying diode bridge (not shown) for controlling energization of the work coil 10, and is rotationally driven by the fan motor 18 and the fan motor 18. And an axial flow impeller 19 which is operated. The bottom wall of the container body 1 (specifically,
A cooling air inlet 20 is formed on the bottom surface of the bottom member 7 so as to face the cooling fan 17.

On the other hand, the lid 2 is made of a synthetic resin (for example, polypropylene) upper plate 21 forming an outer surface and a synthetic resin (for example, polypropylene) doughnut-shaped lower surface forming an inner peripheral surface. It is composed of a plate 22 and a metal radiator plate 23 attached to the lower plate 22,
A hollow part 25 for accommodating the heat insulating material 24 is formed between the upper and lower plates 21 and 22.

The lid body 2 includes a shoulder portion 5b of the outer case 5.
It is removably attached to one side via a hinge pin 26.

At the center of the lid body 2, there is formed a tubular portion 27 which is hung from the upper plate 21, and the inside of the tubular portion 27 discharges steam generated during rice cooking to the outside. It is used as a steam discharge passage 28. A pressure regulating cylinder 30 is attached to the lower end of the cylindrical portion 27 via a seal packing 29.

In the heat dissipation plate 23, the vapor discharge passage 2
8, a hole 31 corresponding to the lower end is formed.
The rim of is sealed and supported by the seal packing 29. The outer peripheral edge of the heat radiating plate 23 is connected to the inner peripheral edge of the lower plate 22 via a seal packing 32. The seal packing 32 is pressed against the upper edge of the inner pot 3 to maintain airtightness when the lid 2 is closed.

On the upper surface of the heat dissipation plate 23, the heat dissipation plate 23
A lid heater 33 is attached to prevent the formation of dew and oneeba by heating.

In the space 4 on the front side of the container body 1 (that is, the side where the lock mechanism 34 for locking the lid 2 is provided), the work coil 10, the heat-retaining heater 13 and the lid heater 33 are provided. A control board 35 incorporating a control unit for controlling energization, various switches (for example,
A switch substrate 36 having a rice cooking switch, a reservation switch, a heat retention switch, etc.) and a liquid crystal display device 37 are arranged.

FIG. 2 shows an electric rice cooker using an electric heater of a hot platen type as a heating means.

This electric rice cooker comprises a main body container 1 configured to accommodate the inner pot 3 and a lid body 2 for covering the upper opening of the main body container 1.

The main body container 1 includes an inner case 42 made of a sheet metal forming an inner peripheral surface, an outer case 43 made of a sheet metal forming an outer peripheral surface, an upper edge of the inner case 42 and the outer case 43. Shoulder member 44 made of synthetic resin for connecting with the upper edge
And a bottom member 45 made of synthetic resin that covers the lower end opening of the outer case 43. The bottom surface of the inner case 42 is provided in a heating plate 46 made of a good heat conductor (for example, aluminum alloy). A hot plate type electric heater 10 having a sheathed heater 47 embedded therein is fixed by screws 48. Then, the inner pot 3 is to be housed in the main body container 1 while being placed on the heating plate 46.

The inner pot 3 is of a round bottom type in which the radius of curvature of the curved portion 3b from the bottom portion 3a to the side peripheral portion 3c is large, and the heating plate 46 is the bottom portion 3a and the curved portion of the inner pot 3. It is shaped so as to enclose 3b. This greatly contributes to the improvement of the heating efficiency.

A hole 49 is formed at the center of the heating plate 46 so as to vertically penetrate therethrough, and the temperature sensor 8a (for example, a thermistor) faces the hole 49 so that the center sensor 8 functions as a temperature detecting means. Are provided so as to penetrate the bottom surface of the inner case 42. A heat retaining heater 6 is arranged at the upper and lower intermediate portions of the outer peripheral surface of the inner case 42.

On the other hand, the lid 2 is made of a synthetic resin (for example, polypropylene) upper plate 21 that forms an outer surface and a synthetic resin (for example, polypropylene) donut-shaped lower plate that forms an inner peripheral surface. It is composed of a plate 22 and a metal radiator plate 23 attached to the lower plate 22,
A hollow part 25 for accommodating the heat insulating material 24 is formed between the upper and lower plates 21 and 22.

The lid 2 is attached to one side of the shoulder member 44 via a hinge pin 26 so as to be rotatable and detachable.

At the center of the lid body 2, there is formed a cylindrical portion 27 which is hung from the upper plate 21. Inside the cylindrical portion 27, steam generated during rice cooking is discharged to the outside. It is used as a steam discharge passage 28. A pressure regulating cylinder 30 is attached to the lower end of the cylindrical portion 27 via a seal packing 29.

In the heat dissipation plate 23, the steam discharge passage 2
8, a hole 31 corresponding to the lower end is formed.
The rim of is sealed and supported by the seal packing 29. The outer peripheral edge of the heat radiating plate 23 is connected to the inner peripheral edge of the lower plate 22 via a seal packing 32. The seal packing 32 is pressed against the upper edge of the inner pot 3 to maintain airtightness when the lid 2 is closed.

On the upper surface of the heat dissipation plate 23, the heat dissipation plate 23
A lid heater 33 is attached to prevent the formation of dew and oneeba by heating.

On the front side of the container body 1 (that is, on the side where the lock mechanism 34 for locking the lid 2 is provided), the electric heater 10, the heat-retaining heater 13, the lid heater 33, etc. are energized. A control board 35 in which a control unit is incorporated and various switches (for example, a rice cooking switch,
A switch board 36 having a reservation switch, a heat retention switch, etc.) is provided.

First Embodiment FIGS. 3 to 5 show an inner pot of an electric rice cooker according to a first embodiment of the present invention.

The inner pot 3 is used for both of the above-mentioned two types of electric rice cookers, and the inner bottom portion corresponds to the heating means 10 (for example, an electric heater or a work coil) (ie, a portion). , A plurality of small projections 5 acting as surface area increasing portions on the bottom portion 3a and the curved portion 3b).
0, 50 ... Are integrally formed.

The small projections 50 are formed by punching the cast inner pot 3 from the outside. Therefore, the recessed portions 51 formed by punching are formed on the outside of each small protrusion 50 (see FIG. 4). Since such a forming method is adopted, the center sensor 8
The small protrusion 50 is not formed in the central portion of the inner pot bottom portion 3a (that is, the portion where the center sensor 8 is abutted) in consideration of the close contact with the. That is, the small protrusions 50, 50 ...
Will be formed in a portion of the inner pot bottom 3a excluding the central portion and the curved portion 3b. In the inner pot bottom 3a, the inner pot bottom 3a is formed so as to have a predetermined interval on a concentric circle and in a staggered arrangement. The inner pot curved portion 3b is formed on the concentric circles with a predetermined interval (see FIG. 5).
The small protrusion 50 may be formed at the time of casting the inner pot 3, and in that case, it may be formed at the center sensor contact portion.

The formation intervals of the small projections 50, 50 ...
At the time of washing the rice, it is desirable that the distance is at least larger than that of the rice grains so that the contact state between the rice grains and the small projections 50, 50 ...

In the case of an electric rice cooker using an electric heater of a heating plate type as a heating means, the inner pot 3 has an aluminum alloy layer 54 as a base material as shown in FIG. In the case of an electric rice cooker that is composed of a fluorine resin coating layer 55 coated on the inner surface side of the aluminum alloy layer 54 and uses an electromagnetic induction coil as a heating means,
As shown in FIG. 4B, the aluminum alloy layer 54 as the base material.
A fluororesin coating layer 55 coated on the inner surface of the aluminum alloy layer 54, and the aluminum alloy layer 5
4 and the stainless steel layer 56 formed on the outer surface side. In the stainless steel layer 56, an eddy current is generated by electromagnetic induction by the work coil 10.

With the above construction, the bottom portion 3a and the curved portion 3b of the inner pot 3 become higher in temperature than the other portions due to the heating action of the heating means 10 during rice cooking, but the small protrusions 50, 50 ... Due to the formation of, the surface area increases, and the heat transfer area in that portion increases. Therefore, uniform heating at the time of rice cooking can be obtained, and a good rice cooking state can be obtained.

Further, due to the formation of the small protrusions 50, 50, ... Bubbles which are generated during rice cooking and move along the inner peripheral surface of the inner pot 3 collide with the small protrusions 50, 50. Before it does, it separates from the inner peripheral surface and many small bubbles are generated. Therefore, a strong convection occurs in the inner pot 3 during rice cooking, and a good rice cooking state can be obtained.

Further, by forming the small protrusions 50, 50, ..., the rice grains can be efficiently washed by the contact between the rice grains and the small protrusions 50, 50 ..

Second Embodiment FIG. 6 shows an inner pot of an electric rice cooker according to a second embodiment of the present invention.

In this case, the film thickness of the fluororesin coating layer in the region F (that is, the bottom portion 3a and the curved portion 3b) where the small protrusions 50, 50 ... Are formed is made larger than the other portions. That is, the number of times the fluororesin coating layer in the shaded portion F in FIG. 6 is coated is larger than in other portions. By doing so, the heat conduction in the shaded area F that becomes high during rice cooking and the heat conduction in the other portion (that is, the side peripheral portion 3c) become substantially the same, and uniform heating during rice cooking is further promoted. ,
It will also contribute to the prevention of charred rice.

The rest of the configuration, functions and effects are the same as in the first embodiment, so a description thereof will be omitted.

Third Embodiment FIG. 7 shows an inner pot of an electric rice cooker according to a third embodiment of the present invention.

In this case, the area F in which the small protrusions 50, 50 ... Are formed (that is, the bottom portion 3a which is the minimum rice cooking area)
And the curved portion 3b), the upper region F'of the side peripheral portion 3c (that is, the region that exceeds the maximum amount of cooked rice), and the intermediate region F "between them.
And the color tone of the fluororesin coating layer is different. This has an advantage that the display of the minimum rice cooking amount and the maximum rice cooking amount can be easily confirmed due to the difference in color tone. In order to make the color tone of the fluororesin coating layer in the region F different from that of the intermediate region F ″, a coating layer having the same color as that of the intermediate region F ″ is formed and a fluororesin having a different tone from that of the intermediate region F ′ is further coated. In some cases, the heat conduction in the region F where the temperature becomes high during rice cooking and the heat conduction in the other portion (that is, the side peripheral portion 3c) become substantially the same, and uniform heating during rice cooking is further promoted. It also contributes to the prevention of charred rice.

The other structure, functions and effects are the same as those in the first embodiment, and the description thereof will be omitted.

Fourth Embodiment FIGS. 8 to 10 show an inner pot of an electric rice cooker according to a fourth embodiment of the present invention.

In this case, in the inner bottom portion of the inner pot 3, a large number of small recesses 52, 52 which act as a surface area increasing portion on the portion corresponding to the heating means 10 (for example, the work coil) (that is, the bottom portion 3a and the curved portion 3b). .. are integrally formed.

Each of the small recesses 52 is formed by punching from the inside of the cast inner pot 3. Therefore, the protruding ridges 53 formed by punching are formed outside the small recesses 52 (see FIG. 9). Since such a forming method is adopted, the center sensor 8
In consideration of the close contact with, the small recess 52 is not formed in the central portion of the inner pot bottom portion 3a (that is, the portion where the center sensor 8 abuts). That is, the small recesses 52, 52 ...
Will be formed in a portion of the inner pot bottom 3a excluding the central portion and the curved portion 3b. In the inner pot bottom 3a, the inner pot bottom 3a is formed so as to have a predetermined interval on a concentric circle and in a staggered arrangement. The inner pot curved portion 3b is formed on the concentric circles with a predetermined interval (see FIG. 10). The small recess 52 may be formed at the time of casting the inner pot 3, and in that case, it may be formed at the center sensor contact portion.

The intervals between the small recesses 52, 52, ...
At the time of washing the rice, it is desirable that the distance is at least larger than that of the rice grains so that the contact state between the rice grains and the small recesses 52, 52 ...

In this case, it is preferable to use the work coil 10 as the heating means because the protruding ridge 53 is formed on the lower surface of the bottom 3a of the inner pot 3. Therefore, inner pot 3
As shown in FIG. 9, the aluminum alloy layer 54 as the base material
A fluororesin coating layer 55 coated on the inner surface of the aluminum alloy layer 54, and the aluminum alloy layer 5
4 and the stainless steel layer 56 formed on the outer surface side. In the stainless steel layer 56, an eddy current is generated by electromagnetic induction by the work coil 10.

With the above-described structure, the bottom portion 3a and the curved portion 3b of the inner pot 3 are heated to a higher temperature than other portions due to the resistance heat of the eddy current generated by the work coil 10 at the time of cooking rice. By forming the recesses 52, 52, ..., The surface area is increased, and the heat transfer area in that portion is increased. Therefore, uniform heating at the time of rice cooking can be obtained, and a good rice cooking state can be obtained.

Further, due to the formation of the small recesses 52, 52, ..., Bubbles generated during rice cooking and moving along the inner peripheral surface of the inner pot 3 come into contact with the small recesses 52, 52 ,. Before it does, it separates from the inner peripheral surface and many small bubbles are generated. Therefore, a strong convection occurs in the inner pot 3 during rice cooking, and a good rice cooking state can be obtained.

Further, by forming the small recesses 52, 52, ..., By contacting the rice grains with the small recesses 52, 52 ,.

Fifth Embodiment FIG. 11 shows an inner pot of an electric rice cooker according to a fifth embodiment of the present invention.

In this case, the second embodiment is different from the above-described second embodiment only in that the surface area increasing portion is the small concave portion 52, and the other constitutions and operational effects are the same as those of the second embodiment.
The description is omitted because it is the same as that of the first embodiment.

Sixth Embodiment FIG. 12 shows an inner pot of an electric rice cooker according to a sixth embodiment of the present invention.

In this case, the third embodiment is different from the above-described third embodiment only in that the surface area increasing portion is the small recess 52, and the other configurations and operational effects are the third.
The description is omitted because it is the same as that of the first embodiment.

Seventh Embodiment FIGS. 13 and 14 show an inner pot of an electric rice cooker according to a seventh embodiment of the present invention.

In this case, in the inner bottom portion of the inner pot 3, a large number of continuous convex portions 57 that act as surface area increasing portions on the portion corresponding to the heating means 10 (for example, the work coil) (that is, the bottom portion 3a and the curved portion 3b). , 57 ... Are integrally formed.

Each convex portion 57 has a predetermined size (that is,
(It is considerably larger than the small projection 50 in the first embodiment) and is formed by punching the cast inner pot 3 from the outside. Therefore, the concave portions 58 formed by stamping are formed outside the respective convex portions 57 (see FIG. 14). Since such a forming method is adopted, the convex portion 57 is formed in the center portion of the inner pot bottom portion 3a (that is, the portion where the center sensor 8 is abutted) in consideration of the close contact with the center sensor 8. Not done.
That is, the convex portions 57, 57 ... Are formed in the portion of the inner pot bottom portion 3a excluding the central portion and the curved portion 3b. The convex portion 57 may be formed at the time of casting the inner pot 3, and in that case, it may be formed at the center sensor contact portion.

As shown in FIG. 14, the inner pot 3 has an aluminum alloy layer 54 as a base material and an aluminum alloy layer 5 as shown in FIG.
4 is composed of a fluororesin coating layer 55 coated on the inner surface side and a stainless steel layer 56 formed on the outer surface side of the aluminum alloy layer 54. In the stainless steel layer 56, an eddy current is generated by electromagnetic induction by the work coil 10.

With the above configuration, the bottom portion 3a and the curved portion 3b of the inner pot 3 are heated to a higher temperature than the other portions due to the resistance heat of the eddy current generated by the work coil 10 during rice cooking. The surface area increases due to the formation of the parts 57, 57, ..., And the heat transfer area in that part increases. Therefore, uniform heating at the time of rice cooking can be obtained, and a good rice cooking state can be obtained.

Further, by forming the convex portions 57, 57 ...
Bubbles that are generated during rice cooking and try to move along the inner peripheral surface of the inner pot 3 are separated from the inner peripheral surface before they grow largely in the valleys of the convex portions 57, 57, ... Will occur. Therefore, when cooking rice, each convex portion 57
A small convection W is generated in the portion corresponding to, strong convection occurs in the inner pot 3, and a good cooked state can be obtained. Moreover, due to the generation of small convection W, ideal heating can be obtained even when cooking a small amount of rice, and delicious rice can be cooked even in a small amount.

Further, the projections 57, 57 ...
By forming the above, the surface area of the stainless steel layer 56 in each convex portion 57 is increased, and many magnetic lines of force from the work coil 10 that were not utilized for heat generation in the related art are absorbed. Therefore, more efficient heating can be obtained during rice cooking.

The other structure, functions and effects are the same as those of the first embodiment, and the explanation thereof is omitted.

Eighth Embodiment FIG. 15 shows an inner pot of an electric rice cooker according to an eighth embodiment of the present invention.

In this case, the region F in which the convex portions 57, 57 ... Are formed (that is, the bottom portion 3a and the curved portion 3b which are the minimum rice cooking amount region) and the upper region F'of the side peripheral portion 3c (that is, Area that exceeds the maximum amount of cooked rice) and the intermediate area between the two
And the color tone of the fluororesin coating layer is different. This has an advantage that the display of the minimum rice cooking amount and the maximum rice cooking amount can be easily confirmed due to the difference in color tone. In order to make the color tone of the fluororesin coating layer in the region F different from that of the intermediate region F ″, a coating layer having the same color as that of the intermediate region F ″ is formed and a fluororesin having a different tone from that of the intermediate region F ′ is further coated. In some cases, the heat conduction in the region F where the temperature becomes high during rice cooking and the heat conduction in the other portion (that is, the side peripheral portion 3c) become substantially the same, and uniform heating during rice cooking is further promoted. It also contributes to the prevention of charred rice.

The other structure, function and effect are the same as those in the first and seventh embodiments, and the description thereof will be omitted.

[0076]

According to the present invention, a large number of surface area increasing portions (for example, small protrusions or small concave portions) are formed on the inner bottom portion (for example, the bottom portion and the curved portion corresponding to the heating means) of the inner pot to cook rice. Since the heat transfer surface area of the portion which becomes high in temperature is increased, it is possible to obtain uniform heating during rice cooking, and there is an effect that a good rice cooked state can be obtained.

Further, due to the formation of the surface area increasing portion (for example, a small protrusion or a small concave portion), the bubbles generated during rice cooking and moving along the inner peripheral surface of the inner pot come into contact with the surface area increasing portion and grow largely. Before being cooked, a large number of small bubbles are generated, and strong convection occurs in the inner pot during rice cooking, so that a good rice cooked state can be obtained.

Further, by forming the surface area increasing portion (for example, small protrusions or small recesses), contact between the rice grains and the surface area increasing portion at the time of washing rice can be obtained, so that the rice washing can be efficiently performed.

Further, if the surface area increasing portion is continuous with a predetermined size and is a convex portion that causes a small convection on the inner surface side during heating, the heating efficiency is significantly increased by the small convection generated on the inner surface side of the convex portion. As a result, the amount of rice is increased and good rice can be obtained.

When the film thickness of the fluororesin coating layer in the area where the surface area increasing portion is formed is made larger than the other portions, uniform heating during rice cooking can be further promoted and charcoal of cooked rice during rice cooking can be prevented. When the color tone of the fluororesin coating layer is made different between the formation area and the other portion, it becomes easy to confirm the rice cooking amount display.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing an example of an electric rice cooker of the present invention.

FIG. 2 is a vertical cross-sectional view showing another example of the electric rice cooker of the present invention.

FIG. 3 is a vertical cross-sectional view of an inner pot of the electric rice cooker according to the first embodiment of the present invention.

FIG. 4 is an enlarged cross-sectional view of a main part of the inner pot of the electric rice cooker according to the first embodiment of the present invention.

FIG. 5 is a half plan view of the inner pot of the electric rice cooker according to the first embodiment of the present invention.

FIG. 6 is a vertical cross-sectional view of an inner pot of an electric rice cooker according to a second embodiment of the present invention.

FIG. 7 is a vertical cross-sectional view of an inner pot of an electric rice cooker according to a third embodiment of the present invention.

FIG. 8 is a vertical cross-sectional view of an inner pot of an electric rice cooker according to a fourth embodiment of the present invention.

FIG. 9 is an enlarged sectional view of a main part of an inner pot of an electric rice cooker according to a fourth embodiment of the present invention.

FIG. 10 is a half plan view of an inner pot of an electric rice cooker according to a fourth embodiment of the present invention.

FIG. 11 is a vertical cross-sectional view of an inner pot of an electric rice cooker according to a fifth embodiment of the present invention.

FIG. 12 is a vertical cross-sectional view of an inner pot of an electric rice cooker according to a sixth embodiment of the present invention.

FIG. 13 is a vertical cross-sectional view of an inner pot of an electric rice cooker according to a seventh embodiment of the present invention.

FIG. 14 is an enlarged cross-sectional view of a main part of an inner pot of an electric rice cooker according to a seventh embodiment of the present invention.

FIG. 15 is a vertical cross-sectional view of an inner pot of an electric rice cooker according to an eighth embodiment of the present invention.

[Explanation of symbols]

1 is a container body, 2 is a lid, 3 is an inner pot, 3a is a bottom part, 3b
Is a curved portion, 3c is a side peripheral portion, 8 is a temperature detecting means (center sensor), 10 is a heating means (electric heater or work coil), 50 is a surface area increasing portion (small protrusion), and 52 is a surface area increasing portion (small recess). ), 57 is a convex portion, F is a surface area increasing portion forming region, and F'is a maximum rice cooking amount excess region.

Claims (9)

[Claims] 1. A container main body configured to set an inner pan therein, and a lid body that covers an upper opening of the container main body so as to be openable and closable, and the inner pan is provided at an inner bottom portion of the container main body. An electric rice cooker provided with a heating means for heating the rice cooker, wherein a large number of surface area increasing portions are formed on the inner bottom portion of the inner pot. 2. The electric rice cooker according to claim 1, wherein the surface area increasing portion is formed in a portion corresponding to the heating means. 3. The electric rice cooker according to claim 1, wherein the surface area increasing portion is not formed at a portion with which the temperature detecting means is brought into contact. 4. The electric rice cooker according to any one of claims 1 to 3, wherein the surface area increasing portion is a small protrusion integrally formed. 5. The electric rice cooker according to any one of claims 1 to 3, wherein the surface area increasing portion is a small concave portion. 6. The electric rice cooker according to claim 4, wherein the interval of forming the surface area increasing portion is larger than that of rice grains. 7. The surface area increasing portion has a predetermined size and is continuous and is a convex portion which causes a small convection on the inner surface side during heating.
An electric rice cooker as described. 8. The electric rice cooker according to claim 1, wherein a film thickness of the fluororesin coating layer in the surface area increasing portion forming region is larger than that of other portions. vessel. 9. The electric rice cooker according to claim 1, wherein a color tone of the fluororesin coating layer is different between the surface area increasing portion forming region and another portion. ..