JPH1066643A - Electric rice cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve convection inside a pot and to eliminate cooking irregularities by constituting a heating coil for induction-heating the pot by the plural pieces of spiral heating coils arranged on a circumferential layer on a pot bottom surface. SOLUTION: In this electric rice cooker provided with an inverter circuit for supplying a high-frequency to the heating coil for induction-heating the pot and a control part for controlling the heating output of the heating coil, the plural spiral heating coils 6 are attached on the circumferential layer at the lower part of a coil base placed at the lower part of the pot by a supporting base. The respective spiral heating coils 6 are serially or parallelly connected, a ferrite core 8 is disposed to the lower part of the spiral heating coils 6 and a magnetic flux is prevented from leaking to the lower part. Also, the spiral heating coils 6 are arranged to the two layers on a circumference, however, they can be arranged on the three layers on the circumference as well. Also, the spiral heating coils 6 are arranged concentrically along the circumference, however, rice with less cooking irregularities is cooked even when they are arranged in a zigzag shape along the circumferential layer.

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 for inductively heating a pot using a heating coil.

[0002]

2. Description of the Related Art Conventionally, a heating coil of an electric rice cooker of this type is generally wound concentrically as shown in FIG.

[0003] The configuration will be described below with reference to FIG. As shown in the figure, a rice cooker main body (hereinafter referred to as a main body) 1 is provided with an upper frame 3 on which a pot 2 is placed,
The upper part of the main body 1 is configured to be covered with a lid 9 so that the pan 2 can be taken out by opening and closing the lid 9. The inner heating coil 19 is arranged concentrically at a position facing the center of the bottom surface of the pot 2 and heats the center of the bottom surface of the pot 2 by induction.
The outer heating coil 20 is arranged concentrically at a position facing the outer peripheral portion of the bottom surface and the lower portion of the side surface of the pan 2, and performs induction heating on the outer peripheral portion of the bottom surface and the lower portion of the side surface of the pan 2.

An inner heating coil 19 and an outer heating coil 20
Are provided concentrically along the outer periphery of the pan 2 and the inner heating coil 19 and the outer heating coil 20 are coil base 4
A ferrite core 8 that is mounted on the support table 7 and is mounted on the support table 7 and absorbs a leakage magnetic flux is provided radially below the support table 7. The pan temperature detection sensor 12 is a pan 2
The bottom temperature of the pan and the presence or absence of the pan 2 are detected, and are provided so as to be in contact with the center of the bottom of the pan 2. The signal from the pan temperature detection sensor-12 is input to the control unit 13 and the control unit 13
Controls the transmission of an inverter circuit 14 provided at the bottom of the main body 1 for supplying a high-frequency current to the inner heating coil 19 and the outer heating coil 20, and controls the operation display section 15 provided at the top of the main body 1. And

In the above configuration, when the pan 2 is inserted into the upper frame 3, the pan temperature detecting sensor 12 detects the presence or absence of the pan 2,
A heating start signal is sent to the control unit 13 and the inverter circuit 14 to enter a heating standby state. And operation display unit 1
When the cooking mode is set in the cooking menu 5 and the rice cooker key is pressed, the control unit 13 controls the operation of the inverter circuit 14, and the inverter circuit 14 controls the inner heating coil 19. And supplying a high-frequency current to the outer heating coil 20,
The inner heating coil 19 and the outer heating coil 20 are
Is heated by induction heating on the entire bottom surface and the lower portion of the side surface, and rice is cooked in a sequence according to the amounts of rice and water in the pot 2.

[0006]

In such a conventional electric rice cooker, an inner heating coil 19 and an outer heating coil 20 are provided.
With this configuration, the entire bottom surface and the lower side portion of the pot 2 are induction-heated. However, in the concentrically wound shape, the target heating area is too large, and the state of mixing of rice and water that has started gelatinization. Then, boiling starts locally from an unstable place, and once boiling starts, convection is concentrated in the so-called crab hole formed in this part, this part becomes soft rice, and from the crab hole At a distant place, the cooked rice is hard and insufficiently heated, so that there is a problem that rice without uniform cooking cannot be obtained.

[0007] This tendency becomes remarkable as the amount of cooked rice increases, and in some cases, crab holes do not occur and a part of the bottom surface is extremely vibrated, resulting in impaired rice production. Has become. This tendency is even more pronounced when rice that is ranked lower in the grade is cooked, and the amount of bittering increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to improve the convection in a pot so as to eliminate uneven cooking and obtain rice suitable for a user's preference.

[0009]

In order to solve the above-mentioned problems, the present invention provides a heating coil for inductively heating a pan, an inverter circuit for supplying a high-frequency current to the heating coil, and heating of the heating coil. A control unit for controlling an output, wherein the heating coil is constituted by a plurality of spiral heating coils having the bottom surface of the pan disposed on a circumferential layer.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A heating coil for inductively heating the pan, an inverter circuit for supplying a high-frequency current to the heating coil, and a control unit for controlling a heating output of the heating coil; By arranging a plurality of spiral heating coils on the circumferential layer, it is possible to stably obtain crab holes by changing the number and position of the spiral heating coils. Good convection can be forcibly generated, and cooked rice can be cooked evenly.

[0011]

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a main body 1 is provided with an upper frame 3 on which a pot 2 is placed, and a coil base 4 is connected to the upper frame 3 by a protection frame 5 to form a space in which the pot 2 can be stored. doing. A spiral heating coil 6 is mounted on a support base 7 on a circumferential layer below the coil base 4 placed below the pan 2. The spiral heating coil 6 is arranged at the bottom of the pot 2 and at the lower part of the side surface. The spiral heating coils 6 are connected in series or in parallel. The ferrite core 8 is disposed below the spiral heating coil 6,
The magnetic flux is prevented from leaking downward. An openable / closable lid 9 is provided on the upper part of the main body 1. Pot 2 on lid 9
Steam tube 1 to release steam when the contents of
The pressure control valve 11 is attached to the steam cylinder 10 in a detachable manner so as to make it difficult for steam to escape at the time of heat retention and to prevent rice from drying.

The pan temperature detecting sensor 12 is configured to come into contact with the outer bottom of the pan 2 through a hole formed at the center of the bottom of the coil base 4 and the support base 7 to detect the temperature at the bottom center of the pan 2 and to detect the temperature of the pan. The presence or absence is detected. The control unit 13
The transmission output of an inverter circuit 14 which is incorporated in a side surface of the main body 1 and supplies a high-frequency current is controlled. The control unit 13
It is driven by operating the operation display unit 15 provided on the upper side surface of the main body 1.

The operation of the above configuration will be described with reference to FIG. Put rice to be cooked in pot 2 and water suitable for it, set it in main body 1, and close lid 8. Press the rice cooker key on the operation display section 15 to start cooking rice. The pan temperature detecting sensor 12 detects the temperature of the pan 2 and sends a signal to the control unit 13. The inverter circuit 14 supplies a high-frequency current to the spiral heating coil 6 based on a previously programmed sequence. Supply. Rice is cooked through pre-cooking, cooking, maintaining boiling, cooking, and steaming processes.
In this process, the magnetic flux of the spiral heating coil 6 causes
Since the bottom and side lower portions of the pot 2 are intensively heated, nucleate boiling occurs in those portions, and crab holes are formed. By changing the arrangement of the spiral heating coil 6, the position of the crab is
The rice cooker can be changed freely according to the condition of the rice, so that crab holes do not occur in an unstable form as in the past, so that an electric rice cooker with very little uneven cooking can be obtained. .

When the height of rice is high by winding the spiral heating coil 6 in two or three stages, the heating of that portion is further enhanced, so that a crab hole that has escaped to the surface can be easily obtained. The effect of rice cooking can be enhanced. Heating is conventionally unstable, and heating occurs in a concentrated manner, resulting in crab holes. However, when heating is performed by the spiral heating coil 6, heating is performed in a dispersed form, so that there is little burning. You can get delicious rice. In the case of crab rice cooking, the surface of the rice does not become hard because convection of water occurs through the crab hole,
Water can evenly flow through the crab hole at the bottom, so that rice that is not bitter can be obtained and rice with very little unevenness can be obtained.

Since the heating as a whole is uniformly performed as described above, the temperature of the bottom of the pan 2 is set to 120 to
By maintaining the temperature at 130 ° C. for 5 to 20 minutes, the heat insulation effect of cooking in a furnace can be obtained, and further, delicious rice with less burning can be obtained.

The arrangement of the spiral heating coil 6 needs to be changed depending on the bottom area of the pot 2, and when the bottom area is large, the number of circumferential layers can be increased from two to three. Further expansion to four layers or five layers can be handled according to the bottom area of the pot 2.

FIG. 3 shows an example in which the spiral heating coils 6 are arranged in two layers on the circumference, and FIG. 4 shows an example in which the coils are arranged in three layers on the circumference. In any case, when the circumference is divided into two,
The number of spiral heating coils 6 on the outer circumferential layer is larger than the number on the inner circumferential layer. 3 and 4, the two-dot chain line distinguishes the inner circumferential layer, the middle circumferential layer, and the outer circumferential layer. The two-dot chain line of the lead line a is the outer circumference circle of the pot 2 and the lead line 2 of b is
The dashed line schematically shows the position of the outer circle of the pot temperature detection sensor-12. In the case of three layers, the number of spiral heating coils 6 is
The middle circumferential layer is halved, and the numbers allocated to the outer circumferential layer and the inner circumferential layer are compared. When the number of the spiral heating coils 6 in the inner circumferential layer is increased, the rice inside becomes soft, and rice with less unevenness cannot be cooked. It has been confirmed by actual rice cooking that rice with less unevenness can be cooked by increasing the number of spiral heating coils 6 in the outer circumferential layer more than in the inner circumferential layer.

In FIGS. 3 and 4, the spiral heating coils 6 are arranged concentrically along the circumference. However, even if the heating coils 6 are arranged in a zigzag along the circumferential layer, it is possible to cook rice with less unevenness in cooking. It is not limited to the above embodiment.

The ferrite core 8 includes a spiral heating coil 6.
3 and 4, it is possible to absorb the leakage flux even if it is placed on the lower side of the cloth as shown by the dotted line in FIGS.

The side heat insulating heater 16 is wound around the upper portion of the outer side of the protective frame 5, and a heat insulating heater 17 is attached to a portion of the cover 9 facing the pot 2, and has a spiral shape on the bottom surface. By keeping the heating coil 6 and the heating ratio in a suitable balance for keeping warm, it is possible to keep warm with little discoloration and odor of rice. Cordrill 18
Is incorporated in the lower part of the main body 1.

[0022]

As described above, according to the first, second, and third aspects of the present invention, the rice is cooked by arranging the spiral heating coil for induction heating the pot along the circumferential layer. Since crab holes for reducing uneven cooking can be freely obtained, rice suitable for a user's preference can be easily obtained. In addition, since the bottom of the pot is heated in a dispersed manner, intensive heating does not occur, and a delicious rice with less burning can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an electric rice cooker according to one embodiment of the present invention.

FIG. 2 is a temperature characteristic diagram at the center of the bottom of the pot of the electric rice cooker.

FIG. 3 is a layout diagram of a spiral heating coil of the electric rice cooker.

FIG. 4 is another layout view of a spiral heating coil of the electric rice cooker.

FIG. 5 is a longitudinal sectional view of a conventional electric rice cooker.

FIG. 6 is a layout diagram of a heating coil of the electric rice cooker.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 2 Pot 6 Spiral heating coil 13 Control part 14 Inverter circuit

Claims (3)

[Claims] 1. A heating coil for inductively heating a pot, an inverter circuit for supplying a high-frequency current to the heating coil, and a control unit for controlling a heating output of the heating coil, wherein the heating coil comprises: An electric rice cooker comprising a plurality of spiral heating coils having a pot bottom arranged on a circumferential layer. 2. The electric rice cooker according to claim 1, wherein the number of the spiral heating coils arranged on the outer circumferential layer is larger than that on the inner circumferential coil. 3. The electric rice cooker according to claim 1, wherein the spiral heating coil is wound in a plurality of layers.