JPH09140565A - Rice cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cook rice in a less irregular boiling condition, and prevent the deterioration of usability by improving heating efficiency and restraining the occurrence of an irregular heating condition. SOLUTION: A plurality of recesses 83 and 84, and projections 85 and 86 are formed on the bottom and the lower side part of a pot 4. The outer lower part of the pot 4 is formed to have curved cross section in such a state as continuous to the lowest part of the pot 4, with a diameter reduction rate gradually increased toward a lower position. Furthermore, the recess 84 on the inner side of the pot 4 is formed to have smaller depth than the recess 83 on the outer side thereof, so as to easily serve rice and prevent the deterioration of cleanability. Alternatively, the inner side of the pot 4 is formed to be smooth and free from irregularities.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a rice cooker that heats a pot or heats the pot with radiant heat or hot air.

[0002]

2. Description of the Related Art In a cooking container in which a heat generating member for electromagnetic induction heating is connected to a container body, for example,
As described in JP 61-23292, JP 61-127593 or JP 61-149298, the contact area between the heat generating member and the container body is provided by providing unevenness on the bottom surface of the container. There are some that have improved binding. This is also advantageous in that the heating efficiency of electromagnetic induction heating can be improved by increasing the area of the heat generating member and the heat generating area, and that the strength can be improved by work hardening.

The container described in the above publication is based on the premise that the bottom surface of the container is heated, and an induction coil is arranged corresponding to the bottom surface of the container. On the other hand, in a rice cooker, it is desirable to heat not only the bottom part of the pot, which is the container, but also the lower part of the side face to evenly heat the inside of the pot and cook rice with less unevenness in cooking. Even if the described configuration is applied as it is, the effect cannot be fully utilized. Rather, the heating of the bottom portion of the pan becomes too strong, while the heating of the lower portion of the side surface becomes weak, which may cause uneven heating.

Further, since the container described in the above publication is premised on heating the bottom portion of the container, the diameter of the lower part of the side surface and the diameter of the upper part of the side surface of the container are almost the same, or press molding is performed. Due to this, the diameter of the lower part of the side surface is slightly smaller. Therefore, it is difficult to visually see the unevenness of the bottom surface of the container, and it is difficult to convey to the user that the above effect is obtained by the unevenness. Along with this, the effect of utilizing the unevenness as part of the design is also weak.

Furthermore, when the structure described in the above publication is applied to a rice cooker as it is, and the inner surface of the pan is made uneven, it becomes difficult for rice to stray due to the uneven shape. If there are large irregularities on the surface, it becomes even harder for the part that is difficult to stand by itself to become more difficult to use, and the attached rice may be difficult to remove when washing the pot after use.

[0006]

As described above, when an uneven portion is to be formed on the pot of the rice cooker to improve the heating efficiency, the unevenness in cooking is prevented and the uneven portion prevents the rice from being cooked unevenly. The issue is not to deteriorate usability.

The present invention is intended to solve such problems, and by appropriately applying the technique of providing the uneven portion to the pan to the rice cooker, the heating efficiency can be improved and the uneven heating can be suppressed. You can cook rice with less unevenness,
Further, it is a first object to provide a rice cooker capable of preventing deterioration of usability due to uneven portions. The second purpose of this rice cooker is to prevent the strength of the pot from being reduced due to the unevenness. A third purpose is to improve design and the like.

[0008]

In order to achieve the first object, the rice cooker according to the first aspect of the present invention has an outer surface shape from the middle front or rear of the entire height or from about 1/3 of the total height to the lower side. The bottom surface of the bottom surface and the outer surface of the curved surface part have a plurality of uneven parts, and the inner surface has unevenness on the outer surface. And a heating means for heating or heating the pot provided at a position corresponding to the bottom surface of the pot and the uneven portions of the curved surface portion. .

When rice is heated or heated by the heating means during rice cooking, the surface area of the pan is increased due to the uneven portion, so that the heating is efficiently performed. In addition, the unevenness on the bottom surface of the pot and the curved surface of the lower part of the side surface prevents the heating of only the bottom part from becoming too strong, and does not weaken the heating of the lower part of the side surface, thus suppressing uneven heating. To be done. At the same time, due to the curved portion, when cooking rice, vigorous convection is generated in the upper portion of the inner surface rather than the lower portion of the inner surface of the pan, and heat is quickly transferred to the upper portion. The heat of the upper portion is quickly transferred to the central portion of the pan farthest from the heating means, and the uneven heating is further reduced. Furthermore, by making the irregularities on the outer surface shallower than the irregularities on the outer surface of the pot, the irregularities on the inner surface of the pot are less likely to hinder the rice from being cooked, and the rice adhering to the irregularities can be easily removed. .

According to a second aspect of the invention, in the rice cooker of the first aspect of the invention, the concavo-convex portion is formed only on the outer surface of the pot, and the inner surface of the pot has a smooth shape without the concavo-convex portion. is there.

With this configuration, the uneven portion on the inner surface of the pan does not hinder the rice from being cooked, and the rice does not easily adhere to the concave portion of the uneven portion and become difficult to pick up.

According to a third aspect of the invention, in the rice cooker according to the first aspect of the invention, in order to achieve the second object as well, the depth of the concave and convex portions is 50% or less of the thickness of the pot. It was done.

This structure prevents the pot from lowering in strength.

According to a fourth aspect of the invention, in the rice cooker according to the first aspect of the invention, in order to achieve the third object as well, the inner surface and the outer surface of the pot have different shapes of the uneven portions. is there.

For example, the uneven portion of the surface has a shape in consideration of the ease of cleaning the rice and the cleanability, and the uneven portion of the outer surface has a shape in consideration of heating efficiency and design.

[0016]

Embodiments of the rice cooker of the present invention will be described below with reference to the drawings. In FIG. 4, which shows the overall cross-sectional view, 1 is a container main body, which is a bottomed cylindrical inner frame 2 having an open top surface, and an outer shell forming the outer shell of the container main body 1 with the inner frame 2 inside. And the frame 3. The inner frame 2 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, which is a container that is detachably accommodated in the inner frame 2.

The shape of the pan 4 for accommodating the rice to be cooked and water is a bottomed cylinder having an open top.
A flange-shaped handle portion 5 horizontally projecting outward is formed on the uppermost portion of the outer surface of the pot 4. The pan 4 is supported in a suspended state by the handle portion 5 thereof resting on the upper end surface of the inner frame 2, and the handle portion 5 is removed between the inner frame 2 and the pot 4 accommodated therein. A predetermined gap 6 of 1 to 4 mm is formed. In addition, the pan 4 is a pan body 7 mainly made of an aluminum material of A3004 series having excellent thermal conductivity, and a heating layer 8 provided from the outer bottom surface part to the lower side surface of the pan body 7.
Are formed. The heating layer 8 is for heating the pot 4, and is made of a magnetic metal material such as SUS430 made of ferritic stainless steel. The inner surface of the pot 4 is coated with a FEP resin to form a primer layer, and then with a transparent PFA resin to form a fluororesin-based coating layer. 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. The shape and manufacturing of the pot 4 will be described later in detail.

Reference numeral 11 is a coil base.
Is made of glass fiber-containing 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 outside the lower part of the inner frame 2, and a predetermined gap 13 of 0.2 to 2 mm is formed between the inner frame 2 and the coil base 11. Reference numeral 14 is an induction coil that heats the heating layer 8 of the pan 4 by electromagnetic induction. The induction coil 14 has a coil base 11
It is spirally wound around and fixed to the outer surface of, and faces the heat generating layer 8 of the pan 4 across the coil base 11, the gap 13, the inner frame 2 and the gap 6. Also, in the coil base 11,
A plate-shaped ferrite cover 15 that covers the induction coil 14 from the outside.
Is installed. The ferrite cover 15 is made of a material having a high magnetic permeability whose main raw material is iron oxide, and has a plurality of holes (not shown) 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 portion 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. In addition, a heat receiving plate 21 that receives radiant heat from the outer surface of the heat generating layer 8 of the pan 4 is provided on the bottom surface of the inner frame 2. The heat receiving plate 21 is located in the vicinity of the heat generating layer 8 which is the main heating portion of the pan 4 and which generates heat by itself. Although it is located near the bottom of the pan 4 in the drawing, the position of the heat receiving plate 21 may be a position facing the side surface of the pan 4 as long as it is near the portion that generates heat and heats the pan 4. Further, the heat receiving plate 21 and the heat generating layer 8 are in contact with each other or a gap of 4 mm or less is formed so that the heat receiving plate 21 is not elastically pressed against the pan 4. The heat receiving plate 21 is made of an aluminum material such as A1050, which is a non-magnetic material with excellent thermal conductivity, and has a thickness of about 0.3 to 2.0 mm, at least on the radiant heat receiving surface side in order to improve heat absorption. , Coating with silicone resin or fluorine resin, or film thickness of 0.5 ~ 15
An alumite film of about μm is formed. Thereby, the heat absorption in the far infrared region is improved, and the radiant heat of the pan 4 can be efficiently absorbed. While cooking rice, the temperature of the pan 4 rises to 100-150 ° C, which is slightly higher than the boiling temperature. At this time, the wavelength of infrared rays radiated from the outer surface of the pan 4 is 3 ~.
This is because most of the wavelengths in the far infrared region of 4 μm or more. A thermal fuse 22 is provided on the back side, that is, the lower side of the heat receiving plate 21, and a pan temperature sensor 23 including a negative characteristic thermistor is provided. The pot temperature sensor 23 detects the temperature of the heat receiving plate 21, so that the temperature of the pot 4 is detected.

A control board 26 is provided in the lower part of the vessel body 1, and a heating board 27 is provided at the rear part of the vessel body 1 between the inner frame 2 and the outer frame 3. It is provided. The heating substrate 27 includes an inverter circuit for supplying a predetermined high frequency current to the induction coil 14.
The switching element 28 forming the inverter circuit is provided with a radiator 29 for heat radiation. Further, for cooling the radiator 29 and the like, an exhaust port 30 is provided on the upper rear surface of the outer frame 3, and an intake port 31 is provided on the lower rear surface and the bottom portion of the outer frame 3. further,
Reference numeral 32 is a cord reel provided on the front side of the bottom of the outer frame 3 for winding the power cord 33.

Reference numeral 41 is a lid that covers the upper opening of the pot 4 so as to be openable and closable. The lid body 41 includes an outer lid 42, an outer lid cover 43 provided along the lower outer periphery of the outer lid 42, and a lower surface of the lid body 31 attached below the outer lid 42 while forming a space. And a heat dissipation plate 44 made of an aluminum material that forms the part. Reference numeral 45 denotes a lid packing sandwiched between the outer lid cover 43 and the heat radiating plate 44, and when the lid 41 is closed, the lower end of the lid packing 45 comes into close contact with the handle portion 5 of the pan 4. Lid
A clamp button 46 is provided on the front side of 41, and by operating this clamp button 46, the lid 41 can be opened with a hinge 47 provided on the rear side of the lid 41 as the center of rotation. Also, on the upper surface, that is, the back surface of the heat sink 44,
A lid heater including a code heater for heating the heat sink 44
48 are provided. The lid heater 48 electrically forms a parallel circuit with the body heater 16. Furthermore, the heat sink
A lid temperature sensor 49 including a negative characteristic thermistor that detects the temperature of the lower surface of the lid body 41 is provided on the back side of the lid body 41. In addition, 50 is a steam port for discharging the steam from the pan 4 to the outside.

Next, the circuit configuration of the rice cooker will be described with reference to FIG. In the figure, reference numeral 51 denotes a microcomputer, which is well known, and in addition to a control device 52 and an arithmetic device 53 which constitute a microprocessor, a time measuring device 54.
And a storage device 55 including a ROM and a RAM. The input side of the microcomputer 51 has an A / D
An input device 56 consisting of a converter is connected, and this input device 56
An operation switch 57, a load detection circuit 58 for detecting the presence or absence of the pan 4, and a power failure detection circuit 59 for detecting a power failure state are respectively connected to the pan temperature sensor 23 and the lid temperature sensor 49 via the. On the other hand, the microcomputer 51
An output device 61 is connected to the output side of, and through this output device 61, the induction heating means 62 as a heating means for electromagnetically heating the pot 4, the body heater 16 and the lid heater 48 are connected and disconnected at the same time. The heater driving means 63 and the like are connected. In addition to these, the output device 61 is connected with a display drive means 65 of an LED display means 64 for displaying operating states such as rice cooking and heat retention, and a display drive means 67 of an LCD display means 66 for displaying time and the like. At the same time, buzzer drive means 69 for controlling the ringing of a buzzer 68 for notifying the end of cooking rice is connected.

Then, the microcomputer 51 detects the operation signal of the operation switch 57 for starting cooking such as rice cooking and heat retention, the temperature data from the pan temperature sensor 23 and the lid temperature sensor 49, and the lower limit detection of the input current of the inverter circuit. By using the pan detection signal from the load detection circuit 58 by the input information and the time information from the time counting means 54 in addition to this input information, the induction heating means 62, in accordance with the control sequence set in the ROM of the storage means 55 in advance, Body heater 16 and lid heater
48, LED display means 64, LCD display means 66, and buzzer 68 are controlled. 71 is a power failure backup means connected to the output device 61, which is a microcomputer when a power failure occurs.
The operation of 51 is guaranteed by the microcomputer drive circuit 72. Further, the induction heating means 62 is provided with a high frequency current generator 73 for supplying a predetermined high frequency current based on an output signal from the microcomputer 51, and an output adjusting circuit 74 for adjusting the heating amount of the pan 4. . 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 to heat the pot 4.

Further, in the heating control by the microcomputer 51, a pan temperature sensor at the time of cooking rice and keeping warm
The control temperature of 23 is controlled within the temperature range of -20 to 150 ° C. For example, in hot water cooking before rice cooking that promotes water absorption of the rice to be cooked, the temperature of the pan 4 is controlled to 45 to 60 ° C., and the temperature at which rice cooking heating is stopped and the temperature shifts to the spotty is the lid temperature sensor 49.
Is based on the temperature detected by the pan temperature sensor 23 when the generation of steam is detected. That is, after boiling, if the temperature rises by about 5 to 15 ° C. with respect to the reference temperature, it is made uneven. Further, the heat retention control is set to 60 to 73 ° C. These temperature controls have the same configuration as the conventional rice cooker.

Here, regarding the shape and manufacturing of the pot 4,
This will be described in detail. As shown in FIG. 3, the outer surface of the pan 4 is
Forming a curved vertical section connected to the lowest part 81 of the outer bottom of the pan 4 with the decreasing rate of the diameter increasing from the height around the middle of the total height H or about 1/3 of the total height H to the lower side. , The lowermost part 81 of the pan 4 (the outermost peripheral part that contacts the table surface when the pan 4 is placed on a flat table surface, etc.)
The diameter A1 of the pot is 3/4 to 1 / of the diameter A2 of the uppermost side 82 of the pot 4.
The shape is 4. In addition, the side surface uppermost portion 82 of the pot 4 referred to here is an uppermost portion of a portion which is not included in the handle portion 5 and is accommodated in the inner frame 2. For example, if the diameter A2 of the uppermost side 82 of the pan 4 is 200 mm, the diameter A1 of the lowermost 81 is 150 mm.
Make it ~ 50 mm.

As shown in FIG. 1, which is a partial cross-sectional view of the pot 4, a plurality of concave and convex portions (recesses 83, 84 and convex portions 85, 86) are provided on both the inner surface side and the outer surface side of the pot 4 or only on the outer surface side. ) Has been formed. The depth B1 of the concave portion 83 formed in the bottom surface portion and the lower portion of the side surface of the heat generating layer 8 is good for cleaning when rice grains adhere to the outer surface of the pan 4, and is not too deep so as not to reduce the strength. , For example, when the material thickness of the pot body 7 is 5 mm,
It is about 0.2 to 2.5 mm, and is about 50% or less of the thickness of the pan 4. On the other hand, the inner surface of the pan 4 is made so that the rice tends to come out easily and the rice adhering to the concave portion 84 can be easily removed.
As shown in FIG. 1 (b), it has a smooth and flat shape with no unevenness, or the depth B2 of the concave portion 84 is set to about 3 mm or less. The relationship between the depth B2 of the concave portion 84 on the inner surface of the pan 4 and the depth B1 of the concave portion 83 of the heating layer 8 on the outer surface of the pan 4 is B2 <B1. Further, the positions of the inner surface concave portion 84 and the outer surface convex portion 85 are matched, and the positions of the inner surface convex portion 86 and the outer surface concave portion 83 are matched so that the inner surface concave portion 84 and the outer surface concave portion 83 are matched. It is desirable to prevent a partial reduction in material thickness that occurs when the recesses 83 face each other. In addition, when the inner surface of the pan 4 is formed into a smooth shape as shown in FIG. 1B, the minimum thickness t1 of the pan body 7 generated at the concave portion 83 is 1 / th of the total thickness t of the pan 4.
Set to 2 or more. Further, if the diameter C2 of the depth direction upper part of the concave portion 84 on the inner surface is too small, the rice adhering to the concave portion 84 will be difficult to take, and if it is too large, the effect of increasing the heating area will be thin, so about 3 to 30 mm. desirable. Furthermore, especially the recess
The shape of 84 is such that the ratio of the diameter C2 to the depth B2 is 1.5 or more (C2 / B2 ≧ 1.5). The same applies to the setting of the diameter C2 of the concave portion 83 on the outer surface. However, in the case of the concave portion 83 on the outer surface, the effect of increasing the heating area is more important than eliminating the difficulty of eating rice.

The recesses 83 and 84 may have a round shape, a polygonal shape as shown in FIG. 2, or an elliptical shape. In addition, a linear bead may be formed, or a dimple or a hexagonal shape may be used. The point is that the contact area between the pot main body 7 and the heat generating layer 8 increases and the heating area increases. . However, in any case, the shape should satisfy the above-described conditions such as dimensions. If the recesses 83, 84 are not round, the diameter of the circle inscribed in the contour is treated as the diameter C1, C2. If the recesses 83, 84 are elliptical in shape, the short diameters may be set as the diameters C1, C2.
The cross-sectional shapes of the concave portions 83, 84 and the convex portions 85, 86 are also shown in FIG.
Various shapes are possible as shown in (a) to (d).
In particular, as shown in FIGS. 1 (c) and 1 (d), the outer surface and the inner surface of the pot 4 may have different concave and convex shapes. Also, pan 4
The outer surface and the inner surface of the may have different uneven planar patterns. Furthermore, the concave portions 83, 84 and the convex portions 85, 86
Even if the concave portions 83 and 84 are mainly formed with respect to the plane,
5,86 may be the main subject. The concave portions 83 and 84 and the convex portions 85 and 86
An appropriate curved surface shape is formed at the corner of the so that there is no sharp corner.

The induction coil 14 is located at a position facing the bottom surface portion of the heating layer 8 and the curved surface portion 87 at the lower portion of the side surface,
Moreover, the concave portion 83 of the heat generating layer 8 is formed in the portion corresponding to the induction coil 14.
And the convex portion 85 is located. However, the concave portions 83, 84 and the convex portions 85, 86 are not provided in the portion where the pot temperature sensor 23 faces, so that the temperature detection is not affected. On the other hand, the recess
Even if the convex portions 83, 84 and the convex portions 85, 86 are formed in the portions not facing the induction coil 14, the effect on the heating efficiency is small, so that they are not provided at least above the middle of the side surface portion of the pan 4.

Next, an example of a method for manufacturing the pan 4 will be described with reference to FIG. In this manufacturing method, the heating layer 8 is joined to the pan body 7 by a molten metal forging method. In FIG. 6, 8A is a heat generating layer member that becomes the heat generating layer 8, and 7A
Is an aluminum melt which is a material of the pot body 7. Further, 91 is a lower die forming the outer surface of the pot 4, 92 is an upper die forming the inner surface of the pot 4, and the lower die 91 and the upper die 92 are opened and closed in the vertical direction. Note that FIG. 6A shows a case where uneven portions are formed on the inner and outer surfaces of the pot 4, and FIG. 6B shows a case where uneven portions are formed only on the outer surface of the pot 4. That is,
In FIG. 6 (a), the lower mold 91 and the upper mold 92 both have concave and convex portions 93 and 94 for forming concave and convex portions 83 and 84 and convex portions 85 and 86 on the inner and outer surfaces of the pot 4. . On the other hand, in the one shown in FIG. 6 (b), only the lower mold 91 is provided with the uneven portion 93 forming the concave portion 83 and the convex portion 85 on the outer surface of the pot 4, and the surface of the upper mold 92 is smooth. It has a shape. Further, 95 is a runner for injecting the molten aluminum 7A into the molds 91, 92.

In the manufacturing, the heat generating layer 8 is formed by pressing the stainless steel plate into a predetermined dish shape.
The heat generating layer member 8A to be formed is formed in advance, and at this time, the concave portion 83 and the convex portion 85 are also formed. After the dish-shaped heat generating layer member 8A is mounted on the lower mold 91 for molten metal forging, molten aluminum melt 7A is poured from the runner 95 onto the heat generating layer member 8A in the molds 91 and 92. Then, the upper mold 91 is pressed from above and molded by a press, and when the aluminum has cooled and solidified, it is taken out from the molds 91 and 92. In the present manufacturing method, the shapes of the bottom surface portion and the lower portion of the side surface of the outer surface of the pan 4 are determined by the shape of the mold during the press molding of the heating layer member 8A, and the shape of the upper side surface of the outer surface of the pan 4 is
The shape of the lower mold 91 during the forging of molten metal is determined, and the shape of the inner surface of the pot 4 is determined by the shape of the upper mold 92 during the forging of molten metal. Each part of the surface of the pot 4 is formed into a free shape by each mold. There are advantages.

In the electromagnetic induction heating, the heat generating layer 8 made of magnetic metal mainly generates heat, but the concave portion 83 and the convex portion 85 increase the area of the heat generating layer 8 and the area to be heated increases, so that the heat generating layer 8 generates heat. Efficiency is improved. Also, the concave portion 83 and the convex portion
Since the joint area between the pan body 7 and the heating layer 8 is increased by 85, the joint strength between the heating layer member 8A and the pan body 7 is increased, and the heat of the heating layer 8 is efficiently transferred to the pan body 7, The heating efficiency of the pan body 7 is improved. Further, since the angle of the heat generating surface changes between the concave portions 83, 84 and the convex portions 85, 86, the heat generating direction is not limited to one direction with respect to the inner surface of the pan 4. Therefore, as compared with the case where the heat generating layer 8 has a smooth and flat shape,
The heat is quickly transferred to the pan body 7 away from the heat generating portion, local heating of the heat generating portion is suppressed, and uneven heating of the entire pan body 7 is suppressed. As a result, the heating density of the inner surface of the pot 4 is reduced, and it is possible to prevent the rice in the portion in contact with the pot 4 from becoming too soft due to excessive heating. Then, by reducing the heating density of the inner surface of the pot 4, the sticking is also reduced. Further, since the concave portions 83 and 84 and the convex portions 85 and 86 are provided on the bottom surface portion and the lower side surface portion of the pot 4, the heating of the bottom surface portion does not become too strong, and the heating of the lower side surface portion does not become weak. There is no fear of uneven heating. In this way, the concave portions 83, 84 and the convex portions 85, 86 have higher heating efficiency than the conventional one and can cook rice with less unevenness in cooking.

Further, the outer surface of the pot 4 is a curve connecting to the lowermost portion 81 of the pot 4 with the diameter decreasing rate increasing from the middle height of the total height H or the height of about 1/3 to the lower side. It has a vertical cross section, and the diameter A1 of the bottom 81 of the pot 4 is 3/4 to 1/4 of the diameter A2 of the top 82 of the side of the pot 4.
In addition, since the induction coil 14 is provided so as to face the curved surface portion 87 that suddenly changes into a round shape in this manner, the induction coil 14 is provided on the inner surface upper portion of the pot 4 rather than the inner surface lower portion of the pot 4. Violent convection occurs and heat is quickly transferred to the upper part, and the heat in the upper part is quickly transferred to the central portion of the pan 4 that is farthest from the heat generating layer 8 that is the heat source. This further reduces uneven heating.

At the same time, the concave portion 83 and the convex portion 85 are formed in the pan 4.
Since it is visible on the outer side surface, it is easy for the user to understand that it has the above-described action and effect, and the effect of utilizing the concave portion 83 and the convex portion 85 as a part of the design is also improved.

The inner surface of the pan 4 has a smooth and flat shape so that the rice can be easily dissipated and can easily be removed when the rice adheres to the recessed portion 84, or the depth B2 of the recessed portion 84 is increased. Since it is about 3 mm or less, it is possible to prevent the usability from being deteriorated due to the concave portions 84 and the convex portions 86. The depth B2 of the recess 84 is set to about 3 mm or less based on the results of practical tests. In a practical test when the diameter C2 of the recess 84 is 3 mm, without the recess 84, there is no problem and the depth B2 of the recess 84 is 1
If the depth B2 of the concave portion 84 is 2 mm, it is difficult to take, and if the depth B2 of the concave portion 84 is 3 mm,
It was difficult to take, and it was difficult to take when the depth B2 of the concave portion 84 was 4 mm. Further, by making the depth B2 of the concave portion 84 shallow, the water level line formed on the inner surface of the pot 4 becomes easy to see.

Further, as described above, the diameter C2 of the recess 84 is
If it is too small, it will be difficult to wipe off the rice adhered to the recess 84,
On the other hand, if it is too large, the effect of increasing the heating area becomes thin, so about 3 to 30 mm is desirable. Where the minimum diameter is 3
mm is based on the result of the practical test. In a practical test when the depth B2 of the concave portion 84 is 3 mm, the diameter C2 of 1 mm cannot be obtained, and when the diameter C2 is 2 mm, the same as when the diameter C2 is 1 mm, and when the diameter C2 is 3 mm. , The same as when the diameter C2 is 1 mm, when the diameter C2 is 4 mm, it is very difficult to take,
If the diameter C2 is 5 mm, it is rather difficult to take, and the diameter C2 is 6 mm.
The result is that there is no problem. On the other hand, the maximum diameter is 30 mm from the point that the larger the diameter C2, the smaller the heat generation area and the appearance of the uneven portion becomes less noticeable.
And However, the maximum diameter is not limited to 30 mm, and may be determined according to the product in consideration of the improvement in heating efficiency and the appearance.

From the above, in the structure of the concave portion 84 and the convex portion 86, the relationship between the diameter C2 and the depth B2 of the concave portion 84 is preferably such that their ratio C2 / B2 is 1.5 or more. From the result, it is desirable that the diameter C2 of the recess 84 is 3 mm or more,
Furthermore, it was concluded that the depth B2 of the recess 84 is preferably 3 mm or less.

Further, since the depths B1 and B2 of the recesses 83 and 84 are set to 50% or less of the material thickness of the pan main body 7, the recesses 83 and 84 and the projections 85 and 86 significantly reduce the strength. Can be prevented. Further, if the positions of the concave portion 84 and the convex portion 86 on the inner surface are aligned with the positions of the convex portion 85 and the concave portion 83 on the outer surface, the strength can be further improved.

Further, according to the manufacturing method of the above-mentioned embodiment, unlike the case where the whole pot 4 is formed by press molding, the uneven shape of the inner surface and the outer surface of the pot 4 can be made different, which is not convenient for press molding. The uneven shape can be set in consideration. For example, as described above, the inner surface is easy to cook rice, easy to see the water line, and easy to clean.
While the depth B2 of the recess 84 is not made too deep, the depth B1 of the recess 83 can be made deeper or the diameter C1 of the recess 83 can be made smaller on the outer surface in order to increase the heat generation area. Also,
While making the pattern on the inner surface less noticeable, the outer surface can be set with an uneven shape in consideration of the design. That is, unlike the case of press molding, it is not necessary to set the outer surface shape in consideration of the inner surface shape, the uneven shape of the outer surface can be freely set, and the designability can be improved. Of course, it is also possible to form the inner surface into a smooth and flat shape and form the concave portion 83 and the convex portion 85 only on the outer surface.

In the above embodiment, the method of manufacturing the pot 4 has been described by taking the molten metal forging method as an example. However, the method of forming the pot body 7 by ordinary die casting or low pressure casting may be used.

Further, as in the above embodiment, the concave portion 83 and the convex portion 85 of the heat generating layer 8 may be formed at the same time when the heat generating layer member 8A before being joined to the pot main body 7 is press-molded.
It may be formed at the time of joining the heating layer member 8A and the pan body 7 by a molten metal forging method or the like. Here, this manufacturing method will be described with reference to FIG. 7. Regarding the parts common to the manufacturing method shown in FIG. 6 described above,
Description is omitted. The difference between FIGS. 7A and 7B is also shown in FIG.
This is the same as the difference between (a) and (b). In this manufacturing method,
When molding the pan body 7 by the molten metal forging method, etc.
Predetermined concavo-convex portions 93 and 94 are formed in advance on the first and second 92, and the heating layer member 8A having no concavo-convex portions is mounted on the lower die 91. Next, the molten aluminum 7A is injected into the molds 91 and 92, and in the case of the molten metal forging method, the upper die pressurizes the pressure. The concavo-convex shape of the lower die 91 is transferred to form the concave portions 83 and the convex portions 85 of the heat generating layer 8. According to this manufacturing method, it is not necessary to previously form the concave portions 83 and the convex portions 85 on the heat generating layer member 8A, and all the concave portions 83, 84 and the convex portions 85, 86 can be easily formed in one step, Manufacturability is improved. Also, when molding the pan body 7,
The concave portion 83 and the convex portion 85 of the heating layer member 8A are replaced by the concave and convex portion 93 of the lower mold 91.
Therefore, the labor of mounting the heat generating layer member 8A on the lower mold 91 is eliminated, and the manufacturability is further improved. At the same time, when the heat generating layer member 8A is mounted on the lower die 91, there is no problem such as a displacement of the concave and convex portions 93 between the lower die 91 and the heat generating layer member 8A, and there is an advantage that the dimensional accuracy can be stabilized. In addition,
The concave portion 83 and the convex portion 85 having a predetermined shape (a dimple, a hexagonal pattern, etc.) can be surely formed also on the side surface portion of the heat generating layer 8.

In the above-mentioned embodiment, the electromagnetic induction heating type rice cooker has been described as an example, but the invention is not limited to this. In a rice cooker in which a pan is placed on a hot plate made of aluminum, etc., the uneven contact area reduces the contact area, which reduces heating efficiency.However, heating means such as a sheath heater is not in contact with the pan. In a rice cooker that heats the bottom part of the pan or the bottom part and the lower part of the side surface with radiant heat, or a rice cooker that heats the pan with hot air, the uneven part increases the heat receiving part, making it an electromagnetic induction heating type rice cooker. Similarly, the effect of suppressing uneven heating can be obtained. In addition, the rice cooker other than the electromagnetic induction heating type does not require the heat generating layer, and the pot may be formed only by the aluminum material.

[0042]

According to the rice cooker of the first aspect of the invention, the outer surface shape from the middle front or back of the entire height or from about 1/3 of the whole height to the lower side has a decreasing rate of the diameter increasing toward the lower side. A pot with a curved part that connects to the bottom of the outer bottom and a plurality of uneven parts formed on the bottom part and the curved part, and a pan provided at a position corresponding to the uneven part of the bottom part and the curved part of the pan. Since the heating means for generating heat or heating is provided, the heating efficiency can be improved, and the uneven cooking can be suppressed and the rice can be cooked with less uneven cooking. Further, since the uneven portion on the inner surface of the pot is shallower than the uneven portion on the outer surface of the pot, it is possible to prevent the usability from being deteriorated due to the uneven portion in terms of ease of cleaning the rice and cleanability.

According to the rice cooker of the second aspect of the present invention, since the concavo-convex portion is formed only on the outer surface of the pot and the inner surface of the pot has a smooth shape, the concavo-convex portion hinders the rice from being cooked. In addition, the rice hardly adheres to the concave portions of the concave-convex portion and becomes difficult to take.

According to the rice cooker of the third aspect of the present invention, in addition to the effect of the first aspect of the invention, the depth of the concave portion of the concave-convex portion is set to 50% or less of the thickness of the pot. Can prevent the strength of the pot from decreasing.

According to the rice cooker of the fourth aspect of the present invention, the inner surface and the outer surface of the pot have different shapes of the uneven portions, so that usability, heating efficiency, designability, etc. can be improved in a well-balanced manner.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a part of a pot showing an embodiment of a rice cooker according to the present invention, in which (a) to (d) show different embodiments.

FIG. 2 is a plan view showing an example of the same recess.

FIG. 3 is a sectional view of half of the pot.

FIG. 4 is a sectional view of the same rice cooker as above.

FIG. 5 is a block diagram showing the configuration of the above electric circuit.

FIG. 6 is a cross-sectional view showing an example of a method for manufacturing the same pot.
(A), (b) has shown another Example, respectively.

FIG. 7 is a cross-sectional view showing another example of the method for manufacturing the same pot.
(A), (b) has shown another Example, respectively.

[Explanation of symbols]

 4 Pan 62 Induction heating means (heating means) 81 Bottom of pan 83 Recess on the outer surface of the pan 84 Recess on the inner surface of the pan 85 Convex portion on the outer surface of the pan 86 Convex portion on the inner surface of the pan 87 Curved surface H Total height of the pan B1 Depth of recess on outer surface of pot B2 Depth of recess on inner surface of pot

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B22D 19/00 B22D 19/00 W

Claims (4)

[Claims] 1. A curved outer surface shape which is connected to the lowermost part of the outer bottom surface while the outer surface shape from the middle of the total height or from about 1/3 of the total height to the lower side has a decreasing rate of diameter increasing as it goes downward. , A pot with a plurality of irregularities formed on the outer surface of the bottom portion and the curved surface portion, and a plurality of irregularities having a shallower depth on the inner surface than the uneven portion of the outer surface, and the bottom portion of the pan and the curved surface portion A rice cooker, which is provided at a position corresponding to the uneven portion of the above, and is provided with heating means for heating or heating the pot. 2. The rice cooker according to claim 1, wherein the pot has a concavo-convex portion only on the outer surface thereof, and the inner surface of the pot has a smooth shape without the concavo-convex portion. 3. The depth of the concave and convex portions is 50% of the thickness of the pan.
The rice cooker according to claim 1, wherein: 4. The rice cooker according to claim 1, wherein the inner surface and the outer surface of the pot have different shapes of the uneven portions.