JP2001299578A - Electromagnetic induction heating equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide electromagnetic induction heating equipment in which cleaning of wares such as an inner pan or washing rice in the inner pan can be carried out without using an ultrasonic vibrator. SOLUTION: A magnetic flux modulation plate 26 is provided that is located between an inner pan 12 and an electromagnetic coil and vibrated by a magnetic field generated in an electromagnetic coil 13 to transmit to the inner pan 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic induction heating apparatus for cooking a food or the like by heating a container by induction loss of the container by generating a magnetic field by an electromagnetic induction coil.

[0002]

2. Description of the Related Art As an example of the use of an electromagnetic induction heating apparatus, an electromagnetic cooker and a rice cooker are generally known. FIG. 16 is a schematic configuration of a conventional rice cooker disclosed in, for example, Japanese Patent Application Laid-Open No. 6-253974. FIG. In the figure, 11
Is a rice cooker main body, 12 is an inner pot that is installed in the rice cooker main body 11 and is a container for holding an object to be heated, and 13 is an electromagnetic induction wired with a gap below the bottom of the inner pot 12 and on the outer periphery of the side. Coil, 14 is a temperature sensor for the inner pot that detects the temperature of the inner pot 12, 15 is an ultrasonic vibrator whose electrode is in contact with or adhered to the side of the inner pot 12, 16 is a high-frequency current to the electromagnetic induction coil 13. A first inverter 17 for flowing is a second inverter for supplying high frequency power to the ultrasonic vibrator 15, and an operation panel 18 is provided on a side of the rice cooker main body 11.

Next, the operation of the conventional rice cooker configured as described above will be described with reference to FIG. In addition,
FIG. 3 is a diagram showing a temperature change of the inner pot in each process of cooking rice. When the inner pot 12 containing the washed rice 1 and an appropriate amount of water 2 is set in the rice cooker main body 11 and a rice cooker switch (not shown) provided on the operation panel 18 is turned on, first, a preheating process is started. In this process, a high frequency current is supplied to the electromagnetic induction coil 13 through the first inverter 16 so as not to exceed 60 ° C., and the rice 1 and the water 2 in the inner pot 12 are heated. At this time, the amount of cooked rice is roughly detected based on the amount of current supplied to the electromagnetic induction coil 13 and the temperature detected by the temperature sensor 14 for the inner pot, and the high frequency power required for ultrasonic vibration is further supplied to the ultrasonic vibrator 15. It is supplied via the second inverter 17.

When about 15 minutes have passed since the start of rice cooking, the rice cooking process is automatically started and the temperature of the inner pot 12 is controlled to 100 ° C., that is, the water in the inner pot 12 is controlled to boil. When the temperature of the inner pot 12 reaches 100 ° C. by this control, this boiling state is continued for about 10 minutes. Thereafter, the power supply to the electromagnetic induction coil 13 is stopped and the steaming process is started. In this steaming process, the state is continued for approximately 15 minutes, and at the end of the steaming process, the end of rice cooking is notified to the user through a display lamp of the operation panel 18 and an end notification sound (not shown).

[0005]

The conventional rice cooker described above promotes water absorption of the rice 1 in the inner pot 12 by ultrasonic vibration during the preheating process, thereby improving the rice cooking performance and shortening the rice cooking time. In the rice cooker in which the ultrasonic vibrator 15 is in contact with the inner pot 12, the inner pot 12 is taken out of the rice cooker body 11 and washed, or the rice 1 is washed in the inner pot 12. In this case, there is a concern that the electrode at the tip of the ultrasonic transducer 15 may be corroded. Also, the ultrasonic vibrator 1
In the rice cooker to which 5 is bonded, the ultrasonic vibrator 15
Are protruding, which makes cleaning difficult and inconvenient.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and ultrasonically vibrates a container, such as an inner pot, without using an ultrasonic vibrator so as to eliminate noise, and produces rice in the container. It is an object of the present invention to provide an electromagnetic induction heating device that can easily wash a container, wash rice in the container, and cook delicious rice even when water absorption is promoted.

[0007]

According to a first aspect of the present invention, there is provided an electromagnetic induction heating apparatus for heating an inner pot by a magnetic field generated in the electromagnetic induction coil. And a diamagnetic material that is provided between the shuttle and the shuttle, and is vibrated by the magnetic field and transmitted to the inner shuttle.

According to a second aspect of the present invention, in the electromagnetic induction heating apparatus, the diamagnetic material has a hole through which a magnetic flux passes, and is provided at a part between the electromagnetic induction coil and the inner hook. is there.

According to a third aspect of the present invention, there is provided an electromagnetic induction heating apparatus having a motor provided below an inner pot, wherein the diamagnetic material is provided at a part between the electromagnetic induction coil and the inner pot. And
The gist is to rotate around the motor.

In the electromagnetic induction heating apparatus according to a fourth aspect of the present invention, the length of the electromagnetic induction coil is such that the coil length of one region sandwiching a line passing through the center of the plane of the inner pot is longer than that of the other region. The gist is that it is set to be longer.

According to a fifth aspect of the present invention, there is provided an electromagnetic induction heating apparatus comprising: a container for holding an object to be heated; an electromagnetic induction coil for electromagnetically inducing the container; an inverter for supplying a high-frequency current flowing through the electromagnetic induction coil; Control means for controlling an inverter, wherein the control means is based on a frequency of the high-frequency current set in accordance with a unique shape and physical properties of the container so as to generate vibration in the container. To control the inverter.

According to a sixth aspect of the present invention, there is provided the electromagnetic induction heating apparatus, wherein an intermediate material for changing magnetic flux is provided between the container and the electromagnetic induction coil, and the intermediate material distorts a magnetic field transmitted to the container.
The vibration generated in the container is amplified.

According to a seventh aspect of the present invention, there is provided the electromagnetic induction heating apparatus, wherein the intermediate material includes a ferromagnetic material, a paramagnetic material, a diamagnetic material,
And their contained substances.

[0014] In the electromagnetic induction heating apparatus according to claim 8 of the present invention, the intermediate member has a hole through which a magnetic flux passes, and is provided at a part between the electromagnetic induction coil and the container.

According to a ninth aspect of the present invention, there is provided an electromagnetic induction heating apparatus in which an intermediate member is rotated, moved backward, or moved up and down.

In the electromagnetic induction heating apparatus according to a tenth aspect of the present invention, the frequency of the high-frequency current flowing through the electromagnetic induction coil is such that the sound speed of the container material is determined by a radial creepage length including a circular arc at the corner of the bottom surface of the container. The divided natural frequency of the container or a frequency that is an integral multiple thereof is equal to the drive frequency of the electromagnetic induction coil or an integer multiple thereof.

An electromagnetic induction heating apparatus according to claim 11 of the present invention has a vibration frequency in an ultrasonic range exceeding 20 KHz.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a cross-sectional view showing a configuration of a rice cooker as an electromagnetic induction heating device according to Embodiment 1 of the present invention, and FIG. 2 is a plan view of the rice cooker with a lid and an inner pot removed. The same or corresponding parts as those in the conventional example described with reference to FIG.

In the figure, 21 is a lid rotatably provided on the rice cooker main body 11, 22 is a lower lid attached to the lid 21, 23 is a lid temperature sensor for detecting the temperature of the lower lid 22, An inverter 24 supplies a high-frequency current to the electromagnetic induction coil 13. Reference numeral 25 denotes a control circuit provided on the operation panel 18 side. The temperature sensor 14 for the inner pot and the temperature sensor 23 for the lid mounted so as to contact the bottom of the inner pot 12.
Then, the rice cooking state is recognized based on the detected temperature, and the inverter 24 is controlled based on this.

Reference numeral 26 denotes a ring-shaped magnetic flux modulation plate made of, for example, any of diamagnetic materials such as copper, silver, graphite, bismuth, and gold.
It is provided between the inner pot 12 and the electromagnetic induction coil 13 around the inner pot temperature sensor 14, and vibrates with a magnetic field generated according to a high-frequency current flowing through the electromagnetic induction coil 13. This vibration is caused by the magnetic flux generated around the electromagnetic induction coil 13 being disturbed by the magnetic flux modulation plate 26 made of a diamagnetic material, and vibrates horizontally with respect to the bottom of the inner pot 12.

Here, experimental results will be described with respect to vibration when the magnetic flux modulation plate 26 is not used and when it is used. When the magnetic flux modulation plate 26 was not used and the frequency of the current flowing through the electromagnetic induction coil 13 was adjusted to the natural frequency of the inner pot 12, the inner pot 12 vibrated and generated noise.
When the vibration at this time was measured using a vibration sensor and an ultrasonic sound pressure gauge, the voltage was 0.1 mV.

On the other hand, the ring-shaped magnetic flux modulation plate 26 is
When a magnetic field was generated in the electromagnetic induction coil 13 at the same frequency as that described above by being disposed between the electromagnetic induction coil 13 and the electromagnetic induction coil 13, vibration with a large amplitude was generated without generating noise. The vibration at this time is measured by the same method as described above.
The voltage was 0 mV, indicating that the amplitude of the vibration was larger than that of the former.

When the magnetic flux modulation plate 26 is not used, a force for vibrating the inner pot 12 in the vertical direction is generated, but the weight (several kg) of the inner pot 12 containing the rice 1 and the water 2 is generated. A comparable force was not generated, and was insufficient to vibrate the entire inner pot 12.

Next, the operation of the rice cooker according to Embodiment 1 will be described with reference to FIGS. FIG. 4 is a timing chart showing the operation of the electromagnetic induction coil in each step of rice cooking. For convenience of explanation of the operation, the operation of cooking rice by heat generated by induction heating will be described first, and then the vibration of the magnetic flux modulation plate will be described. When the inner pot 12 containing the washed rice 1 and an appropriate amount of water 2 is set in the rice cooker main body 11 and the start of rice cooking is operated on the operation panel 18, the control circuit unit 25 is started.
Controls the inverter 24 to energize the electromagnetic induction coil 13 (high-frequency current), and enters a preheating process. In this process, the amount of current supplied to the electromagnetic induction coil 13 is controlled through the inverter 24 so that the temperature of the inner pot 12 becomes approximately 60 ° C.

When about 15 minutes have passed since the start of rice cooking, the rice cooking process is automatically started, and the power supply to the electromagnetic induction coil 13 is controlled so that the temperature of the inner pot 12 reaches 100 ° C. At this time, the temperature of the inner pot 12 is monitored through the detected temperatures of the inner pot temperature sensor 14 and the lid temperature sensor 23, and
When the temperature reaches 0 ° C., the inverter 24 is controlled so that the temperature of the inner pot 12 is maintained at 100 ° C. Then, when it is detected through the inner pot temperature sensor 14 that the water in the inner pot 12 has run out, the control of the inverter 24 is stopped and the steaming process is started. In this steaming process, the inner pot 1
In order to maintain the temperature of 2 at 100 ° C., the electromagnetic induction coil 13 is intermittently energized for about 15 minutes.

On the other hand, the magnetic flux modulation plate 26 vibrates when a current flows through the electromagnetic induction coil 13 during the preheating process and the rice cooking process. It vibrates in the horizontal direction due to a magnetic field generated based on the direction of the current flowing through the electromagnetic induction coil 13. This vibration is caused by the magnetic flux modulating plate 26 disturbing the magnetic flux as described above, and becomes an ultrasonic wave to vibrate the inner pot 12 and transmit it to the rice 1 and the water 2 therein.

The hardness and stickiness of the rice cooked while the magnetic flux modulation plate 26 is vibrated and the rice cooked by the usual method which is not cooked are shown in Table 1 below. The numerical values shown in Table 1 are the results obtained by measuring rice with a rheometer. The hardness of rice cooked during vibration is smaller than that of rice not subjected to vibration, that is, the rice is softer. The value was larger for the rice that was subjected to vibration, and the result was that sticky rice was produced.

[0028]

[Table 1]

As described above, in the first embodiment, the ring-shaped magnetic flux modulation plate 26 disposed between the inner pot 12 and the electromagnetic induction coil 13 is vibrated by the magnetic field generated in the electromagnetic induction coil 13. As a result, the ultrasonic vibrator 15 as in the prior art is not required, so that the inner pot 12 can be easily attached and detached, and the inner pot 12 can be easily washed and rice-washed in the inner pot 12, and it is delicious. There is an effect that you can cook.

Embodiment 2 FIG. FIG. 5 is a cross-sectional view illustrating a configuration of a rice cooker as an electromagnetic induction heating device according to Embodiment 2 of the present invention, and FIG. 6 is a plan view of the rice cooker when a lid and an inner pot that is a container are removed. The same or corresponding parts as in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the figure, 28 is a coil base, 51 is a ferromagnetic material (eg, iron, cobalt, nickel), a paramagnetic material (eg, aluminum, chromium, titanium), a diamagnetic material (eg, graphite, bismuth, copper) ,
A magnetic flux modulation plate which is a ring-shaped intermediate material made of silver, gold) and a substance containing them, which is provided between the inner pot 12 and the electromagnetic induction coil 13 around the inner pot temperature sensor 14, The magnetic field generated in accordance with the high-frequency current flowing through the coil 13 is distorted, and acts to amplify the vibration of the inner hook 12. This vibration is generated by the magnetic flux modulating plate 51 disturbing the magnetic flux generated around the electromagnetic induction coil 13.

Here, experimental results will be described with respect to vibration when the magnetic flux modulation plate 51 is not used and when it is used. In the case where the magnetic flux modulation plate 51 was not used, when the frequency of the current flowing through the electromagnetic induction coil 13 was adjusted to the natural frequency of the inner pot 12, the inner pot 12 vibrated and generated noise.
When the vibration at this time was measured using a vibration sensor and an ultrasonic sound pressure gauge, the voltage was 0.1 mV.

On the other hand, the ring-shaped magnetic flux modulation plate 51 is
When a magnetic field was generated in the electromagnetic induction coil 13 at the same frequency as that described above by being disposed between the electromagnetic induction coil 13 and the electromagnetic induction coil 13, vibration with a large amplitude was generated without generating noise. The vibration at this time is measured by the same method as described above.
The voltage was 0 mV, indicating that the amplitude of the vibration was larger than that of the former.

Next, the operation of the rice cooker according to the second embodiment will be described with reference to FIGS. FIG. 4 is a timing chart showing the operation of the electromagnetic induction coil in each step of rice cooking. The operation of cooking rice by the heat generated by the induction heating is the same as that of the first embodiment, and the description is omitted, and the vibration of the magnetic flux modulation plate will be described.

The magnetic flux modulation plate 51 concentrates the magnetic field generated when a current flows through the electromagnetic induction coil 13 in the inner pot 12 in the preheating process and the rice cooking process, and generates local heat and power. The inner pot 12 is vibrated by a magnetic field generated based on a current flowing through the electromagnetic induction coil 13. This vibration is generated by the electromagnetic induction coil 13 and the inner hook 12 as described above.
This occurs when the magnetic flux modulating plate 51 disposed between them disturbs the magnetic flux, causes the inner pot 12 to vibrate, and transmits the vibration to the rice 1 and the water 2 therein.

Since the frequency of this vibration becomes noise in the audible range, the vibration in the ultrasonic range exceeding 20 KHz causes the inner pot 12 to vibrate without any problem and transmits this vibration to the rice 1 and the water 2. be able to. The shape of the magnetic flux modulation plate 51 is
The ring shape shown in FIGS. 5 and 6 or a partially cut-out portion as shown in FIG. 7 may be used. This improves the heat generation temperature distribution of the inner pot 12. This arrangement includes the electromagnetic induction coil 13 side as shown in FIG. 8, the inner pot 12 side as shown in FIG.
As shown in FIG. 0, a form integrally formed with the coil base 28 of the electromagnetic induction coil 13 may be used.

The hardness and stickiness of the rice cooked while the inner pot 12 is vibrated by the magnetic flux modulation plate 51 and the rice cooked by the usual method which is not the same are as shown in Table 1 described above. The numerical values shown in Table 1 are the results obtained by measuring rice with a rheometer. The hardness of rice cooked during vibration is smaller than that of rice not subjected to vibration, that is, the rice is softer. The value was larger for the rice that was subjected to vibration, and the result was that sticky rice was produced.

As described above, in the second embodiment, since the magnetic flux is disturbed by the magnetic flux modulation plate 51 to vibrate the inner pot 12, the ultrasonic vibrator 15 as in the prior art becomes unnecessary. For this reason, the attachment and detachment of the inner pot 12 is easy, and washing of the inner pot 12 and washing of rice in the inner pot 12 can be easily performed.
It has the effect of making delicious rice.

Embodiment 3 FIG. 11 is a plan view of a rice cooker according to Embodiment 3 of the present invention, showing a state where a lid and an inner pot have been removed from the rice cooker main body. Note that the same or corresponding parts as those in the above embodiment are denoted by the same reference numerals, and description thereof will be omitted.
The rice cooker according to the present embodiment has an inner pot 12 as shown in FIG.
A magnetic flux modulation plate 31 is arranged at a part between the magnetic induction coil 13 and the electromagnetic induction coil 13. This magnetic flux modulation plate 31
Is formed along a part of the surface formed from the bottom side to the curved portion. The magnetic flux modulation plate 31 has holes 3
2 are provided.

The hole 32 is for passing the magnetic flux from the electromagnetic induction coil 13 located below the magnetic flux modulation plate 31 to the inner pot 12 side. Is reduced, and the difference in the heat generation temperature of the inner pot 12 is reduced.

When a high-frequency current flows through the electromagnetic induction coil 13 due to the operation of the inverter 24, the electromagnetic induction coil 13
A magnetic field is generated in the internal combustion chamber to generate heat, and the magnetic flux modulation plate 31 vibrates in the horizontal direction due to the magnetic field of the nearby electromagnetic induction coil 13. This vibration is caused by the magnetic flux modulation plate 31 disturbing the magnetic flux as described above, and becomes an ultrasonic wave to vibrate the inner pot 12. At this time, the holes 32 provided in the magnetic flux modulation plate 31
, A part of the magnetic flux passes through and passes through the bottom of the inner pot 12. When the vibration of the magnetic flux modulation plate 31 at this time is measured by the vibration sensor and the ultrasonic sound pressure gauge in the same manner as described above, the vibration becomes 2.6 mV, which is higher than 2.0 mV in the first embodiment, and the amplitude of the vibration increases. I have.

As described above, since the magnetic flux modulation plate 31 having the hole 32 is disposed at a part between the inner pot 12 and the electromagnetic induction coil 13 to vibrate, the heat generation temperature of the inner pot 12 is reduced. It is possible to cook soft and sticky rice with almost no difference in height, and since the ultrasonic vibrator 15 is not attached to the inner pot 12 unlike the prior art, the inner pot 12
There is an effect that the attachment / detachment is easy.

Embodiment 4 FIG. FIG. 12 is a plan view of a rice cooker according to Embodiment 4 of the present invention, showing a state where a lid and an inner pot have been removed from the rice cooker main body. Note that the same or corresponding parts as those in the above embodiment are denoted by the same reference numerals, and description thereof will be omitted.
The rice cooker according to the present embodiment has an inner pot 12 as shown in FIG.
The magnetic flux modulation plate 52 is arranged at a part between the magnetic flux modulation plate 13 and the electromagnetic induction coil 13. This magnetic flux modulation plate 52 is
Is formed along a part of the surface formed from the bottom side to the curved portion. The magnetic flux modulation plate 52 has holes 5
3 are provided.

The hole 53 is for passing the magnetic flux from the electromagnetic induction coil 13 located below the magnetic flux modulation plate 52 to the inner pot 12 side. Is reduced, and the difference in the heat generation temperature of the inner pot 12 is reduced.

When a high-frequency current corresponding to the natural frequency of the inner pot 12 flows through the electromagnetic induction coil 13 by the operation of the inverter 24, the magnetic field generated from the electromagnetic induction coil 13 is changed by the magnetic flux modulation plate 52 to a specific portion, for example, a magnetic flux modulation. Board 5
In the case where copper is used as the copper 2, since it acts on the inner pot 12 intensively around the magnetic flux modulation plate 52, a force is generated simultaneously with heat, and
2 vibrates while generating heat. Since a part of the magnetic flux passes through the hole 53 provided in the magnetic flux modulation plate 52 and passes through the bottom of the inner pot 12, it is possible to prevent an extreme temperature distribution from occurring. When the vibration of the magnetic flux modulation plate 52 at this time is measured by the vibration sensor and the ultrasonic sound pressure gauge in the same manner as described above, it becomes 2.6 mV, which is higher than 2.0 mV in the first embodiment.
The amplitude of the vibration is large.

As described above, the magnetic flux modulation plate 52 having the hole 53 is arranged at a part between the inner pot 12 and the electromagnetic induction coil 13 so that the inner pot 12 is vibrated.
The soft and sticky rice can be cooked with almost no difference in the temperature of the heating temperature of No. 2 and the ultrasonic vibrator 15 is not attached to the inner pot 12 unlike the prior art. There is an effect that attachment and detachment are easy.

Embodiment 5 FIG. 13 is a cross-sectional view illustrating a configuration of a rice cooker according to Embodiment 5 of the present invention. The same or corresponding portions as those in the above-described embodiment are denoted by the same reference numerals and description thereof is omitted. The rice cooker according to the present embodiment is configured such that the length of the spiral electromagnetic induction coil 13 is such that the coil length in one region sandwiching a line passing through the center of the plane of the inner pot is longer than the coil length in the other region. Is set. That is, as shown in FIG.
Are wired in a zigzag manner. Further, a temperature sensor 14 for the inner kettle disposed on the center axis of the inner kettle 12 is provided.
Below the motor 4, a motor 4 for rotating a magnetic flux modulation plate 42 described later is provided.
1 is provided.

When the motor 41 is energized, the magnetic flux modulation plate 42 is turned on by 3 to 30 times per minute.
Is controlled by the control circuit unit 25 so as to rotate at the frequency.
The above-described magnetic flux modulation plate 42 has substantially the same outer shape as the magnetic flux modulation plate 31 of the second embodiment, and does not have the holes 32 unlike the magnetic flux modulation plate 31.

In the rice cooker of the present embodiment, when a high-frequency current flows through the electromagnetic induction coil 13 in each of the preheating step and the rice cooking step, the magnetic flux modulation plate 42 vibrates and the inner pot 12 and the electromagnetic induction coil are vibrated. 13 is rotated by a motor 41 to vibrate the inner hook 12. At this time, the inner pot 12
Are vibrated in the horizontal direction and generate heat due to the magnetic field generated in the serpentine electromagnetic induction coil 13 wired on the side.

As described above, in the present embodiment, the magnetic flux modulation plate 42 that rotates while vibrating between the inner pot 12 and the electromagnetic induction coil 13, and the magnetic field generated in the electromagnetic induction coil 13 wired in a zigzag pattern The inner pot 12 is caused to vibrate, so that the water absorption of the rice 1 can be further promoted, and the magnetic flux from the electromagnetic induction coil 13 is transferred to the inner pot 12.
This has the effect that rice can be cooked without causing a distribution in the heat generation temperature of the inner pot 12.

Embodiment 6 FIG. FIG. 14 is a cross-sectional view showing a configuration of a rice cooker according to Embodiment 6 of the present invention. The same or corresponding parts as those in the above-described embodiment are denoted by the same reference numerals and description thereof is omitted. In the rice cooker according to the present embodiment, a motor 54 for rotating a magnetic flux modulation plate 55 described below is provided below the temperature sensor 14 for the inner pot arranged on the central axis of the inner pot 12.

When the motor 54 is energized, the motor 54 changes the magnetic flux modulation plate 55 from 3 to 30 (times / minute).
Is controlled by the control circuit unit 25 so as to rotate at the frequency.
The magnetic flux modulation plate 55 described above has substantially the same outer shape as the magnetic flux modulation plate 52 of the fourth embodiment, and does not have the holes 32 unlike the magnetic flux modulation plate 52.

In the rice cooker of the present embodiment, the inner pot 12 is attached to the electromagnetic induction coil 13 in each of the preheating step and the rice cooking step.
When a high-frequency current corresponding to the natural frequency flows, the magnetic flux modulation plate 55 vibrates while rotating between the inner pot 12 and the electromagnetic induction coil 13 by the motor 54 to vibrate the inner pot 12.

As described above, in the present embodiment, the inner pot 12 is vibrated by the magnetic flux modulation plate 55 which rotates while vibrating between the inner pot 12 and the electromagnetic induction coil 13. Can be further promoted,
Further, the magnetic flux from the electromagnetic induction coil 13 can be transmitted uniformly to the inner pot 12, and there is an effect that rice can be cooked without generating a distribution in the heat generation temperature of the inner pot 12.

In the present embodiment, the magnetic flux modulation plate 55
Is rotated, but the magnetic flux modulation plate 55 may be moved back and forth or up and down.

Embodiment 7 FIG. FIG. 15 is a cross-sectional view illustrating a configuration of a rice cooker according to Embodiment 7 of the present invention. The same or corresponding portions as those in the above-described embodiment are denoted by the same reference numerals and description thereof is omitted. Reference numeral 27 denotes a control circuit unit which is a control means provided on the operation panel 18 side. The control circuit 27 includes an inverter 24 based on a temperature detected by the inner pot temperature sensor 14 and the lid temperature sensor 23 attached to the bottom of the inner pot 12. Is controlled, and the inverter 24 is controlled based on the frequency of the high-frequency current set in accordance with the unique shape and physical properties of the inner pot 12 so as to generate vibration in the inner pot 12.

The rice cooker of the present embodiment has a control circuit 27
, The natural frequency S = V / 2 · L calculated from the radial creepage length L including the arc of the corner of the bottom of the inner pot 12 and the sound velocity V of the material of the inner pot 12, or the natural frequency S
The electromagnetic induction coil 13 is set to be driven by a high-frequency current having a drive frequency F equal to an integer multiple n × S The driving frequency F of the electromagnetic induction coil 13 is F = n × S (n = 1, 2,
3... Integer) That is, when the frequency of the electromagnetic induction coil 13 and the natural frequency of the inner hook 12 match, the inner hook 12 resonates,
The drive frequency F of the electromagnetic induction coil 13 is determined so that a larger vibration occurs. This resonance phenomenon also occurs when the integral frequency of the driving frequency F of the electromagnetic induction coil 13 and the integral frequency of the natural frequency S of the inner hook 12 match, so that these frequencies are matched. ing. Then, the inverter 24 is controlled based on the frequency thus set.

When the magnetic flux generated from the electromagnetic induction coil 13 is modulated by the magnetic flux modulation plate 26, a concentrated excitation force is generated, and the inner pot 12 itself vibrates. At this time, the vibration having a large amplitude can be obtained even with a small excitation force by matching the natural frequency of the inner hook 12. The same effect can be obtained by matching the integral multiple of the natural frequency of the inner hook 12 with the integral multiple of the drive frequency of the electromagnetic induction coil 13.

As described above, in the present embodiment, the inner hook 12
Is adjusted so that the integral multiple of the natural frequency of the electromagnetic induction coil and the integral multiple of the drive frequency of the electromagnetic induction coil 13 (both include 1), so that there is an effect that a large vibration can be generated even with a small excitation force. . Although the first to seventh embodiments show rice cookers, the inner pot may be used as a container for electromagnetic induction heating of other foods.

[0060]

According to the first aspect of the present invention, the diamagnetic material provided between the inner pot and the electromagnetic induction coil is transmitted to the inner pot by vibrating with the magnetic field generated in the electromagnetic induction coil. This eliminates the need for an ultrasonic vibrator as in the prior art, making it easy to attach and detach the inner pot, making it easier to clean the inner pot and wash rice in the inner pot, and to make delicious rice This has the effect.

According to the second aspect of the present invention, the diamagnetic material having a hole through which the magnetic flux passes is provided between the inner pot and the electromagnetic induction coil so as to vibrate. It is possible to cook soft and sticky rice with almost no difference in height, and because the ultrasonic vibrator is not attached to the inner pot as in the prior art, the inner pot can be easily attached and detached. There is.

According to the third aspect of the present invention, since the space between the inner pot and the electromagnetic induction coil is rotated while the diamagnetic material is vibrated, the magnetic flux from the electromagnetic induction coil is uniformly applied to the inner pot. Therefore, there is an effect that rice can be cooked without causing a distribution in the heat generation temperature of the inner pot.

According to the invention of claim 4 of the present invention, since the coil length of one region sandwiching the line passing through the center of the plane of the inner hook is set to be longer than the coil length of the other region, The inner pot vibrates due to the magnetic field generated in the long coil, and the vibration of the diamagnetic material that rotates between the inner pot and the electromagnetic induction coil is also transmitted, further promoting water absorption of rice in the inner pot. It has the effect of being done.

According to the fifth aspect of the present invention, a container for holding an object to be heated, an electromagnetic induction coil for electromagnetically inducing the container, an inverter for supplying a high-frequency current flowing through the electromagnetic induction coil, and the inverter An electromagnetic induction heating apparatus comprising: a control unit that controls the inverter based on a frequency of the high-frequency current set in accordance with a unique shape and physical properties of the container so as to generate vibration in the container. , The container itself vibrates, eliminating the need for an ultrasonic vibrator as in the prior art, and therefore, the container can be easily attached and detached, the container can be easily cleaned, and delicious rice can be obtained.

According to the invention of claim 6 of the present invention, an intermediate member for changing magnetic flux is provided between the container and the electromagnetic induction coil,
This intermediate material distorts the magnetic field transmitted to the container and amplifies the vibration generated in the container, so that the vibration generated in the container can be amplified.

According to the invention of claim 7 of the present invention, since the intermediate material is a ferromagnetic material, a paramagnetic material, a diamagnetic material, or a substance containing them, it is possible to amplify the vibration generated in the container. it can.

According to the eighth aspect of the present invention, since the intermediate member has a hole through which the magnetic flux passes and is provided at a part between the electromagnetic induction coil and the container, the heat generation temperature of the inner pot is increased. It is possible to cook soft and sticky rice with almost no difference in height.

In the electromagnetic induction heating apparatus according to the ninth aspect of the present invention, the intermediate member is rotated, or moved back and forth, or moved up and down, so that the generation of ultrasonic waves can be amplified.
The temperature distribution can be improved.

According to the tenth aspect of the present invention, the frequency of the high-frequency current flowing through the electromagnetic induction coil is obtained by dividing the sound velocity of the container material by the radial creepage length including the arc of the corner of the container bottom. The natural frequency of the container, or a frequency of an integral multiple thereof, and the driving frequency of the electromagnetic induction coil,
Alternatively, since it is made equal to an integral multiple thereof, large vibration can be generated even with a small excitation force, and amplification of ultrasonic generation can be performed at a larger frequency.

According to the eleventh aspect of the present invention, since the frequency of vibration is in the ultrasonic range exceeding 20 KHz, generation of noise can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a rice cooker according to Embodiment 1 of the present invention.

FIG. 2 is a plan view of the rice cooker with a lid and an inner pot removed.

FIG. 3 is a diagram showing a temperature change of an inner pot in each process of rice cooking.

FIG. 4 is a timing chart showing the operation of the electromagnetic induction coil in each step of rice cooking.

FIG. 5 is a cross-sectional view illustrating a configuration of a rice cooker according to Embodiment 2 of the present invention.

FIG. 6 is a plan view of the rice cooker when a lid and an inner pot are removed.

FIG. 7 is a plan view of a magnetic flux modulation plate of the rice cooker according to Embodiment 2 of the present invention.

FIG. 8 is a cross-sectional view of an arrangement example of a magnetic flux modulation plate of a rice cooker according to Embodiment 2 of the present invention.

FIG. 9 is a cross-sectional view of an arrangement example of a magnetic flux modulation plate of a rice cooker according to Embodiment 2 of the present invention.

FIG. 10 is a cross-sectional view of an arrangement example of a magnetic flux modulation plate of a rice cooker according to Embodiment 2 of the present invention.

FIG. 11 is a plan view of a rice cooker according to Embodiment 3 of the present invention.

FIG. 12 is a plan view of a rice cooker according to Embodiment 4 of the present invention.

FIG. 13 is a sectional view showing a configuration of a rice cooker according to Embodiment 5 of the present invention.

FIG. 14 is a cross-sectional view illustrating a configuration of a rice cooker according to Embodiment 6 of the present invention.

FIG. 15 is a sectional view showing a configuration of a rice cooker according to Embodiment 7 of the present invention.

FIG. 16 is a sectional view showing a schematic configuration of a conventional rice cooker.

[Explanation of symbols]

11 rice cooker body, 12 inner pot, 13 electromagnetic induction coil, 14 temperature sensor for inner pot, 18 operation panel, 21
Lid, 22 Lower lid, 23 Lid temperature sensor, 24 Inverter, 25, 27 Control circuit, 26, 31, 4
2, 51, 52, 54, 55 Magnetic flux modulation plates, 41, 54
motor.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Tanaka 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsui Electric Co., Ltd. (72) Yoshiro Furuishi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Ryo Denki Co., Ltd. In Home Equipment Co., Ltd. Home Equipment Co., Ltd. (72) Inventor Koji Hishiyama 1728-1 Komaeda, Oaza-gun, Hanazono-cho, Osato-gun, Saitama Inside Rishi Electric Home Equipment Co., Ltd. (72) Inventor, Takehiko Hara 1728-1, Koeda, Oaza, Hanazono-cho, Osato-gun, Saitama Prefecture Inside Mitsubishi Electric Home Equipment Co., Ltd. Mitsubishi Electric Home Equipment Co., Ltd. F term (reference) 4B055 AA03 BA28 BA32 BA38 BA56 BA63 BA68 CA16 CB02 CC04 CC43 CD02 CD58 DA02 DA03 DB14 FA16 FB01 FB02 FB03 FB04 FB06 GA04 GB08 GB29 GC17 GD05

Claims (11)

[Claims] 1. An electromagnetic induction heating device for heating an inner pot by a magnetic field generated in an electromagnetic induction coil, wherein the heating apparatus is provided between the electromagnetic induction coil and the inner pot, and vibrates by the magnetic field to the inner pot. An electromagnetic induction heating device comprising a diamagnetic material for transmitting. 2. The electromagnetic induction heating apparatus according to claim 1, wherein the diamagnetic material has a hole through which a magnetic flux passes, and is provided at a part between the electromagnetic induction coil and the inner pot. . 3. It has a motor provided below the inner hook,
The electromagnetic induction heating device according to claim 1, wherein the diamagnetic material is provided at a part between the electromagnetic induction coil and the inner pot, and rotates about the motor. 4. The length of the electromagnetic induction coil is set such that the coil length in one region sandwiching a line passing through the center of the plane of the inner hook is longer than the coil length in the other region. The electromagnetic induction heating apparatus according to claim 3, wherein 5. An electromagnetic induction system comprising: a container for storing an object to be heated; an electromagnetic induction coil for electromagnetically inducing the container; an inverter for supplying a high-frequency current flowing through the electromagnetic induction coil; and control means for controlling the inverter. In the heating apparatus, the control unit controls an inverter based on a frequency of the high-frequency current set in accordance with a unique shape and physical properties of the container so as to generate vibration in the container. Heating equipment. 6. An intermediate material for changing magnetic flux between a container and an electromagnetic induction coil, wherein the intermediate material distorts a magnetic field transmitted to the container and amplifies vibration generated in the container. Electromagnetic induction heating device. 7. The electromagnetic induction heating apparatus according to claim 6, wherein the intermediate material is a ferromagnetic material, a paramagnetic material, a diamagnetic material, or a substance containing them. 8. The intermediate member has a hole through which magnetic flux passes,
The electromagnetic induction heating device according to claim 6, wherein the electromagnetic induction heating device is provided at a part between the electromagnetic induction coil and the container. 9. The electromagnetic induction heating apparatus according to claim 6, wherein the intermediate member is rotated, moved backward, or moved up and down. 10. The frequency of the high-frequency current flowing through the electromagnetic induction coil is determined by dividing the sound speed of the container material by a radial creepage length including an arc of a corner of the container bottom surface, or the natural frequency of the container. The electromagnetic induction heating device according to any one of claims 5 to 9, wherein an integral multiple of the frequency is equal to a drive frequency of the electromagnetic induction coil or an integral multiple thereof. 11. The electromagnetic induction heating apparatus according to claim 5, wherein the frequency of the vibration is in an ultrasonic range exceeding 20 KHz.