JPH06296551A - Rice cooker - Google Patents

Abstract

PURPOSE:To make the speed of heat conduction steady, to advance the time to end boiling and to reduce uneven cooking result and scorching by forming the inner pot in the approximate hemispheric shape with a concaved flat face provided at the center of its bottom. CONSTITUTION:The bottom of the inner pot 10 forms at its center a circular concaved flat face 10a caving inwards slightly. Here, the corner part of the inner pot 10 forms an approximate hemisphere of the curved surface in long radius, and accordingly, even when the quantity of rice to be cooked is small, the thickness of layer Dn of rice (ri) is maintained high. As a result, the difference of distances from the bottom of pot being small, the transmission of heat to the central part is made fast. The heat is given from the outside of inner pot 10 and transmitted to the central part. Here, the temperature sensor 16 touches the concaved flat face 10a at the center of the inner pot 10 closely under pressure of spring of the sensor spring 17 and detects the exact cooking temperature, preventing the lowering of cooking accuracy. Further, the height of coil (nn) becomes high, leading to the ideal cooking temperature characteristics.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art FIG. 5 is a structural explanatory view of a conventional rice cooker, FIG.
Is a side view showing a part of the inner pot of FIG. 5 in cross section, FIG. 7 is a front view of another conventional rice cooker, and FIG. 7 shows the rice cooker described in Japanese Utility Model Publication No. 2-40330. There is.

In FIG. 5, 1 is a rice cooker, 2 is a main body, and 3
Is a lid, and 4 is an outer case. Reference numeral 5 is an upper frame, and 10 is an inner pot. A magnetic material is used for the inner pot 10, and the corner of the pot bottom is formed into a curved surface with a small radius r as shown in FIG. 12 is a coil base, 13 is a heating coil, 14 is ferrite, 16 is a temperature sensor, and 18 is a cord reel. 20 is an operation unit provided on the lid 3, 21 is a display window,
22 is a touch key. In addition, in the conventional rice cooker of FIG. 7, 13 is a rice cooker which replaces a heating coil.
0 is formed into a nearly perfect hemisphere as shown. r
i is rice and wa is water.

The operation of the conventional rice cooker having such a structure is
It will be described next. When rice cooking is started by the operation unit 20, the power switch is turned on and the heating coil 13 is energized. The inner kettle 10 is driven by the magnetic flux generated by the heating coil 13 when energized.
Heats up. The generated heat of the inner pot 10 is gradually transmitted from the outside toward the center, and the temperature of the water wa inside rises. When the rice cooking progresses and the water wa boils to reduce the water content in the inner pot 10 to reach the rice cooking end temperature, the heating coil 13 is automatically de-energized to cook the rice.

[0005]

When the cooking of rice is started as described above, the heat of the inner pot 10 that has generated heat is gradually transferred toward the center according to the shape and the inside is heated. Therefore, in the conventional rice cooker in which the corner of the pot bottom has a curved surface with a small radius r, a heat transfer delay occurs in the vicinity of the central portion far from the inner pot 10. When the heat transfer is slowed down, heating becomes uneven, which causes uneven cooking and charring.

On the other hand, in the conventional rice cooker shown in FIG. 7,
Since the inner pot 10 is formed into a completely hemispherical shape, there is a feature that the delay of heat in the central portion can be reduced. However, when the inner pot 10 is taken out from the main body 2 and placed on a cooking table or the like, the arrangement becomes unstable and the water wa and rice ri in the interior are spilled or shaken during washing, which is extremely inconvenient. . A pedestal provided with a plurality of columns 9 as shown in FIG.
It is also conceivable to place 0s and arrange them stably. However, not only special accessories have to be prepared, but also the heights of the columns 9 need to be correct, which increases the total manufacturing cost. Further, since the inner pot 10 is directly mounted on the support column 9, there is a problem that the temperature of the inner pot 10 at the mounting portion locally rises to cause temperature unevenness.

The present invention has been made in order to solve the problems of the conventional rice cooker, and improves the structure of the inner pot to eliminate the heat transfer delay near the central portion and improve the rice cooking accuracy. At the same time, it is an object of the present invention to realize a rice cooker that can be stably arranged as it is on a flat surface such as a cooking table and is easy to handle.

[0008]

According to the present invention, there is provided a main body in which a heating means is provided inside and an upper portion is opened and closed by a lid, and an inner pot which is removably accommodated in the main body and is heated by the heating means. In the rice cooker provided, a rice cooker in which the inner pot has a substantially hemispherical shape in which a concave plane is provided at the center of the bottom surface is configured.

Further, a heating means is provided inside and a main body whose upper part is opened and closed by a lid, an inner pot which is removably housed in the main body and is heated by the heating unit, and a bottom face of the inner pot which are in contact with each other. In a rice cooker equipped with a temperature sensor for controlling the rice cooking operation, the rice cooker is configured such that the inner pot has a substantially hemispherical shape with a concave plane at the center of the bottom face, and the temperature sensor is in contact with the concave plane of the inner pot. It is composed.

Further, a main body having a heating coil inside and an upper portion opened and closed by a lid, an inner pot which is removably housed inside the main unit and generates heat by an electromagnetic induction action of the heating coil, and a bottom face of the inner pot. In a rice cooker equipped with a temperature sensor for contacting and controlling the rice cooking operation, the inner pot is formed into a substantially hemispherical shape having a concave plane at the center of the bottom face, and the temperature sensor is brought into contact with the concave plane of the inner pot. The rice cooker has heating coils arranged along a hemisphere.

[0011]

[Function] After putting sharpened rice and water in the inner pot, set it in the main body, attach the inner lid and close the lid. Since the corner of the inner pot is formed into a hemispherical bottom with a curved surface with a large radius, even when the amount of cooked rice is small, the rice layer immersed in water in the inner pot has a uniform thickness. To be kept. When you press the rice cooking start key, the power switch is turned on and the heating coil is energized.

An electric current flows through the heating coil by energization, and the heat generated in the inner pot is propagated to the water inside and heated from the surroundings. The heat transferred to the peripheral part is transferred to the central part, and the rice soaked with water as a heat medium is also heated. At the same time, detection of the temperature of the temperature sensor starts. The temperature sensor receives the spring pressure of the sensor spring and comes into close contact with the concave flat surface at the center of the inner pot without any gap, and the accurate cooking temperature can be detected.

As the rice cooking progresses, the temperature of the water in the inner pot rises, and at time, boiling starts from the peripheral portion. Since the bottom of the inner pot is formed in a substantially hemispherical shape, the difference in the distance from the bottom of the pot is small, and the heat reaches the center while the heat is rapidly propagated to the end of boiling. Then, when the water content in the inner pot is reduced and the temperature reaches the rice cooking end temperature, the controller automatically stops energizing the heating coil to cook the rice and start eating.

When the push button is pressed after eating, the lid automatically rotates to open the upper surface of the main body. The inner pot is once taken out from the opened main body onto the cooking table, and the dirty inner pot is washed at the washing place. The washed inner pot is wiped of water and placed on the counter. Since a concave flat surface is formed on the bottom surface of the inner pot, the inner surface of the inner pot can be stably arranged without being shaken due to circular line contact with a flat surface such as a washing room or a cooking table.

[0015]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a structural explanatory view of an embodiment of the present invention, FIG.
FIG. 2 is a side sectional view of the inner pot of FIG. 1. In the embodiments of the present invention, the same parts as those in the conventional art are designated by the same reference numerals and the description thereof will be duplicated, but will be described in some detail.

In FIG. 1, 1 is a rice cooker and 2 is a rice cooker 1.
The main body 3 is a lid. Reference numeral 4 denotes an outer case of the main body 2, which is composed of a side case 4a and a bottom case 4b. Reference numeral 5 is an annular upper frame, 6 is a metal cylinder, 7 is a body heater, and 8 is a heat shield wall. The upper frame 5 closes a gap on the upper surface of the main body 2 and is provided with a mounting portion 5a protruding from the inner peripheral edge thereof for mounting an inner pot described below.

Reference numeral 10 is an inner pot. As the inner pot 10, a clad steel plate having a two-layer structure of a metal plate is used. The inner layer is made of aluminum and the outer layer is made of a magnetic material. As shown in FIG. 2, the inner bottom of the inner pot 10 is formed with a circular concave plane 10a which is slightly inwardly concaved in the center, and a corner 10b surrounding the concave plane 10a has a large radius R1 close to the radius R. It is composed of an almost hemispherical shape.

12 is a coil base, 13 is a heating coil,
Reference numeral 14 is ferrite arranged radially. The coil base 12 is made of a heat-resistant non-magnetic material such as nylon resin and is molded in a pot bottom type having a central hole.

Reference numeral 16 is a temperature sensor, and 17 is a sensor spring. The temperature sensor 16 uses the sensor spring 17 to move the inner pot 10
It always contacts the concave plane 10a. Reference numeral 18 is a cord reel provided at the bottom of the main body 2 and connected to a plug, and 19 is a power board. A power transformer 19a is mounted on the power board 19 together with other electronic components such as a microcomputer (not shown) for controlling the rice cooking operation.

Reference numeral 20 is an operation unit. The operation unit 20 is arranged on the inclined surface of the side case 4a. Although not shown in detail, an operation sheet is attached to the surface of the operation unit 20, and touch keys such as a display window and a start key are provided. Further, on the operation board on the back side of the operation unit 20, electronic parts such as LEDs, liquid crystal displays and switches are mounted in correspondence with the display window and the touch keys.

Reference numerals 31 and 32 are upper and lower cases of the lid 3, 33 is a push button, 34 is a radiator plate, and 35 is a lid heater. 36 is a shaft fixed to the heat dissipation plate 34, 37 is an inner lid, 38 is packing, and 39 is a steam cylinder. Inner lid 37
Is removably attached to the shaft 36 via a packing 38. 40 is a hinge mechanism, 41 is a hinge mechanism 4
0 is a hinge spring, and 42 is a hinge shaft. Also, in FIG.
As in the case of 7, ri is rice and wa is water.

Generally, in this type of rice cooker, the radiant heat of the inner pot 10 is propagated to the internal water wa and the rice ri soaked is cooked. Therefore, the rice temperature in the peripheral portion near the inner pot 10 tends to be high and gradually lower from the peripheral portion toward the central portion. The change in the rice temperature T with respect to the time t is shown by the curve C in FIG. At the time t1 when the rice is started to be cooked, the boiling of the portion where the temperature rises quickly such as the peripheral portion of the inner pot 10 starts, and the boiling of the portion where the temperature rises slowly such as the center ends at the time t2.

As shown by the diagonal lines in FIG. 3, the change in the rice temperature T shows a characteristic like a hysteresis curve having a time width, and the ideal curve Cu is shown by a two-dot chain line. The difference between the time tve until the boiling ends and the time tvs when the boiling starts (Δt = t2
By shortening -t1) as much as possible, the change in the rice temperature approaches the ideal curve Cu, and the rice can be cooked without unevenness or sticking. Tal in FIG. 3 is the total cooking time.

On the other hand, rice cookers are usually divided into models according to the amount of cooked rice, and inner pots of different sizes are used according to the models. For example, for rice cookers according to the amount of rice cooked, "gogo kaki"
Inner pots classified as "Yago-kaki" and "1 shobaki" are prepared. By cooking rice with the rice cooker according to the amount of rice cooked, the rice cooker suitable for a family structure is selected.
In particular, small families use small rice cookers with a small amount of rice, and the layer thickness Dn of rice deposited on the bottom of the pot is higher than that of the conventional Do. The thick rice layer prevents the rice cooking accuracy from decreasing.

Here, in the rice cooker of the present invention having the above-mentioned structure, after putting the polished rice ri and water wa in the inner pot 10, the rice cooker is set in the main body 2 and the inner lid 37 is attached to attach the lid. Three
Close. In this case, since the corner of the inner pot 10 is formed into a substantially hemispherical bottom having a curved surface with a large radius, even if the amount of cooked rice is small, the rice r i dipped in the water Wa in the inner pot 10 The layer thickness Dn is kept higher than the conventional layer thickness Do (FIG. 4). Next, the cord is pulled out from the cord reel 18 and the insertion plug is connected to a power outlet. While watching the display of the operation unit 20 on the side surface of the main body 2, operate the touch key and press the rice cooking start key. At the start of rice cooking, the power switch is turned on and the heating coil 13 is energized.

A high-frequency exciting current flows through the heating coil 13 due to the energization, and the alternating magnetic flux thus generated causes the inner pot 1 of the cladding material.
Joule heat is generated due to the eddy current, which is linked to 0. The heat generated in the inner pot 10 by such an electromagnetic induction action is transmitted to the water wa in the inner pot 10 and is heated from the surroundings. The heat transmitted to the peripheral portion is further transmitted to the central portion of the inner pot 10, and the rice ri soaked using water wa as a heat medium is also heated. At the same time, detection of the temperature of the temperature sensor 16 starts. At this time, the temperature sensor 16 receives the spring pressure of the sensor spring 17 and comes into close contact with the concave flat surface 10a of the central portion of the inner pot 10 without any gap, and the accurate cooked rice temperature is detected.

As the rice cooking progresses, the temperature of the water wa in the inner pot 10 rises, and at time t1, boiling starts from the peripheral portion. As described above, since the bottom of the inner pot 10 is formed in a substantially hemispherical shape, the difference in the distance from the bottom is small and the heat is rapidly propagated to the center while the boiling end time continues. Reach Tve. Then, when the water content in the inner pot 10 decreases to reach the rice cooking end temperature, the heating coil 13 is controlled by the controller.
Energization is automatically stopped, rice is cooked and meals can be started at the scheduled time.

A comparative diagram of the operation of the embodiment of the present invention and the conventional rice cooker is shown in FIGS. 4 (a) and 4 (b). (a) is a conventional rice cooker at a distance Lo from the corner 10b near the center,
(b) shows the operation of the rice cooker of the present invention having a short distance Ln. As is clear from the comparison between the (a) diagram and the (b) diagram, the inner pot 1
The layer thicknesses D0 and Dn of rice ri dipped in 0 are D0 <D
Due to the relationship of n, it is possible to prevent a decrease in rice cooking accuracy due to the thin layer. Further, in the present invention, since the inner pot 10 is formed in a substantially hemispherical pot bottom, the coil height hn of the heating coil 13 having the same number of turns becomes higher than that of ho and the ideal rice temperature characteristic. The heating efficiency is high and it is economical.

When the push button 33 is pressed after eating, the lid 3
Is automatically rotated about the hinge shaft 42 by the hinge spring 41 to open the upper surface of the main body 2. From the opened main body 2, the inner pot 10 is once taken out on the cooking table. afterwards,
The removed inner pot 10 is washed in the sink of the cooking table. The washed inner pot 10 is wiped of the washing water and placed on the cooking table again. In this case, since the concave plane 10a is formed on the bottom surface of the inner pot 10, the line is circularly contacted with a plane such as a washing room or a cooking table, so that it can be stably arranged without shaking.

In the above-mentioned embodiments, the case of the electromagnetic induction heating type rice cooker has been described as an example, but a part of the present invention can be applied to an electric heating type rice cooker. Also, especially
Although not shown, the shape of the inner pot may be close to a square as long as the corner of the bottom of the pot is a large curved surface and is almost hemispherical. It is not limited.

[0031]

According to the present invention, a rice cooker is provided with a main body which has heating means inside and whose top is opened and closed by a lid, and an inner pot which is removably housed inside the main body and is heated by the heating means. In the above, a rice cooker in which the inner pot has a substantially hemispherical shape in which a concave plane is provided at the center of the bottom surface is constructed.

Further, a heating means is provided inside and a main body whose upper portion is opened and closed by a lid, an inner pot which is removably housed inside the main body and is heated by the heating unit, and abutting on the bottom of the inner pot. In a rice cooker equipped with a temperature sensor for controlling rice cooking operation, the inner rice cooker is configured in a substantially hemispherical shape with a concave flat surface at the center of the bottom surface, and the temperature sensor is brought into contact with the concave flat surface of the inner rice cooker. Configured the vessel.

Further, a main body in which a heating coil is provided and an upper part is opened and closed by a lid, an inner pot which is removably housed in the main body and generates heat by electromagnetic induction of the heating coil, and a bottom face of the inner pot are provided. In a rice cooker equipped with a temperature sensor for contacting and controlling the rice cooking operation, the inner pot is formed into a substantially hemispherical shape having a concave plane at the center of the bottom face, and the temperature sensor is brought into contact with the concave plane of the inner pot. , A rice cooker in which heating coils are arranged along the hemisphere.

As a result, as compared with the conventional case, there is no delay in heat transfer, the boiling end time is shortened, and uneven cooking and burning can be reduced. Moreover, since the bottom surface of the bottom of the pot is provided with a concave flat surface, it is very convenient to be stably arranged on the cooking table or the like. In particular, since the temperature sensor is in close contact with the concave surface, you can cook delicious rice without lowering the detection sensitivity.

Therefore, according to the present invention, it is possible to realize a rice cooker which has high rice cooking accuracy and is economical, and which can be stably arranged on a cooking table or the like and is easy to handle.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of an embodiment of the present invention.

FIG. 2 is a cross-sectional explanatory view of the inner pot of FIG.

FIG. 3 is an explanatory diagram showing a rice temperature characteristic.

FIG. 4 is an explanatory diagram showing the operation of the present invention.

FIG. 5 is an explanatory diagram of a configuration of a conventional rice cooker.

FIG. 6 is a cross-sectional explanatory view of an inner pot of a conventional rice cooker.

FIG. 7 is a configuration explanatory view of another conventional rice cooker.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rice cooker 2 Main body 3 Lid body 4 Outer case 10 Inner pot 10a Concave plane 10b Corner 11 Outer pot 12 Coil base 13 Heating coil 16 Temperature sensor 17 Sensor spring 18 Code reel 20 Operation part 33 Push button 37 Inner lid 40 Hinge mechanism 42 Hinge axis C Curve R Radius R1 Large radius ri Rice wa Water

Claims (3)

[Claims] 1. A rice cooker comprising a main body having a heating means inside and an upper part opened and closed by a lid, and an inner pot removably accommodated in the main body and heated by the heating means. A rice cooker characterized in that the inner pot is formed in a substantially hemispherical shape having a concave plane at the center of the bottom surface. 2. A main body having a heating means inside and an upper part opened and closed by a lid, an inner pot removably accommodated in the main body and heated by the heating unit, and a bottom face of the inner pot. In a rice cooker provided with a temperature sensor that abuts and controls rice cooking operation, the inner pot is configured in a substantially hemispherical shape with a concave plane at the center of the bottom surface, and the temperature sensor is applied to the concave plane of the inner pot. A rice cooker characterized by being in contact. 3. A main body in which a heating coil is provided inside and an upper part of which is opened and closed by a lid, an inner pot which is removably accommodated in the main body and is heated by an electromagnetic induction action of the heating coil, and In a rice cooker equipped with a temperature sensor for controlling rice cooking operation by contacting a bottom surface of a rice cooker, the inner rice cooker is formed into a substantially hemispherical shape having a concave plane at the center of the bottom surface, A rice cooker in which a temperature sensor is brought into contact and the heating coil is arranged along a hemispherical surface.