JP2014220181A - Induction heating cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an induction heating cooker which can perform an appropriate heating depending on a state of a heated object in each process of rice cooking, or makes it easy to prevent overheat of an induction heating coil and reduces the number of components thereby to achieve compactification of the device.SOLUTION: An induction heating cooker comprises below an induction heating coil 1, a ferrite 2 arranged in a rotatable manner and driving means 8 for rotatably driving the ferrite 2, in which the ferrite 2 is intermittently driven so as to be kept at a preset rotation angle from the start of rotation to the stop of rotation in processes from heating to boiling and in a keep-boiling process.

Description

  The present invention relates to an induction heating cooker, and more particularly to a rice cooker or an IH cooking heater.

  2. Description of the Related Art Conventionally, in induction heating cookers that are widely available to the general public, the lines of magnetic force generated by an electromagnetic induction heating coil provided inside the main body constitute a pot on the main body or a pan on the main body top glass. When entering an electromagnetic induction heatable metal or carbon-based material, an eddy current is generated in the metal or carbon-based material. The electric resistance of the eddy current generates heat in the pot or pan, and the contents of the pot or pan are cooked. It is applied to do.

  In addition to heating the heated container such as a kettle or a pan uniformly, the convection state of the contents is changed by changing the heating state, and the contents are heated uniformly. A magnetic member disposed between the heating coils for partially concentrating the magnetic lines of force; and a driving means for moving the magnetic member to change the concentration position of the magnetic lines of force; The convection state of the container in the magnetic force concentration region is activated by the magnetic member with the portion as the rotation center (see, for example, Patent Document 1).

  In addition, in the case where a plurality of ferrites provided directly under the coil are made movable and rotated around the pan, the process of rotating the ferrite is any of pre-cooking, boiling maintenance, cooking, additional cooking, and heat insulation. The rotational speed is set to about 0.3 to 10 [rpm] (for example, see Patent Document 2).

JP 2002-75619 A (summary) JP 2001-149218 A (summary)

In order to cook rice with an induction heating cooker, it is necessary to appropriately heat the rice to be heated (rice, water, etc.) put in the kettle or pan. That is, in each rice cooking process, there are a process suitable for heating the kettle or pan uniformly, and a process suitable for heating the kettle or pan partially in a concentrated manner.
However, although the conventional technology activates the convection state in the magnetic force concentration region by rotating the magnetic member (ferrite), there is a problem that heating suitable for each step of rice cooking is not performed. It was.

Further, when the magnetic flux is concentrated by the magnetic member (ferrite), the kettle or the pan becomes locally hot, so that the induction heating coil is locally overheated.
In addition, in an induction heating cooker, it is desired to reduce the number of parts and reduce the manufacturing cost, and to reduce the size of the apparatus.

This invention is made | formed in order to solve the above subjects, and obtains the induction heating cooking appliance which can perform suitable heating according to the state of the to-be-heated thing in each process which cooks rice. is there.
Moreover, the induction heating cooking appliance which can make it easy to prevent overheating of an induction heating coil is obtained.
Moreover, it is possible to reduce the number of parts, reduce the manufacturing cost, and obtain an induction heating cooker that can reduce the size of the apparatus.

  The induction heating cooker according to the present invention controls an induction heating coil and energization to the induction heating coil, and performs a preheating water absorption process, a heating to boiling process, a boiling maintenance process, a cooking process, a steaming process, and a heat retaining process. Control means for implementing, one or a plurality of ferrites rotatably provided below the induction heating coil, and drive means for rotating the ferrite controlled by the control means, the control means In the heating to boiling step and the boiling maintaining step, the ferrite is intermittently driven to rotate so that the rotation angle from the start of rotation to the stop of rotation becomes a preset angle.

The present invention can perform appropriate heating according to the state of the object to be heated in each step of cooking rice.
In addition, overheating of the induction heating coil can be easily prevented.
Further, the number of parts can be reduced to reduce the manufacturing cost, and the apparatus can be made compact.

It is a cross-sectional schematic diagram which shows roughly an example of a structure of the rice cooker which concerns on Embodiment 1 of this invention. It is a figure explaining the arrangement | positioning angle of the ferrite 2 which concerns on Embodiment 1 of this invention. It is a figure which shows the transition of the temperature of the inner pot 6 in the rice cooking process and heat retention process of the rice cooker which concerns on Embodiment 1 of this invention, and the electricity supply to the electromagnetic induction heating coil 1. FIG. It is a cross-sectional schematic diagram which shows roughly an example of a structure of the rice cooker which concerns on Embodiment 2 of this invention. It is a figure which shows transition of the temperature of the inner pot 6 in the rice cooking process and heat retention process of the rice cooker which concerns on Embodiment 2 of this invention, the electricity supply to the electromagnetic induction heating coil 1, and the rotation speed of the cooling fan 5. FIG. . It is a cross-sectional schematic diagram which shows roughly an example of a structure of the rice cooker which concerns on Embodiment 3 of this invention. It is a plane schematic diagram which shows schematically the structure of the cooling fan 5 which concerns on Embodiment 3 of this invention. It is a cross-sectional schematic diagram which shows schematically the structure of the cooling fan 5 which concerns on Embodiment 3 of this invention.

  Hereinafter, as an example of the induction heating cooker of the present invention, a rice cooker that heats an inner pot by electromagnetic induction heating will be described as an example. In addition, the induction heating cooking appliance of this invention is not limited to this, For example, it can apply also to the IH cooking heater etc. which electromagnetically heat the pan placed on the top plate.

Embodiment 1 FIG.
FIG. 1 is a schematic cross-sectional view schematically showing an example of the configuration of the rice cooker according to Embodiment 1 of the present invention.
As shown in FIG. 1, in the body of the rice cooker, there are an electromagnetic induction heating coil 1, a ferrite 2, a pot temperature detection sensor 3, a heating control board 4, a cooling fan 5, a ferrite support base 7, a drive motor 8, and a control. Means 10 are provided. Moreover, the cover body 9 to which an upper opening part is attached so that opening and closing is possible is provided in the upper part of the main body of the rice cooker.
This rice cooker is provided with an inner pot 6 in which an object to be heated (food such as rice and water) is placed, and the inner pot 6 is heated by the electromagnetic induction heating coil 1 to cook the object to be heated.

The electromagnetic induction heating coil 1 is for inductively heating the inner pot 6 by controlling energization by the control means 10.
The inner hook 6 has a bottomed cylindrical shape, for example, and is made of a material (for example, a magnetic metal) that generates heat by induction heating.

  The hook temperature detection sensor 3 is composed of, for example, a thermistor and detects the temperature of the inner hook 6. The hook temperature detection sensor 3 is biased upward by elastic means such as a spring, and is configured to contact the bottom surface of the inner hook 6. Information regarding the temperature of the inner hook 6 detected by the hook temperature detection sensor 3 is output to the control means 10.

The heating control board 4 is equipped with a control means 10 and an inverter circuit for generating a high-frequency current.
For example, the cooling fan 5 is disposed below the heating control board 4 and supplies cooling air. The cooling air supplied from the cooling fan 5 is supplied to the electromagnetic induction heating coil 1 after cooling the heating control board 4.

  The control means 10 is a high-frequency current to be passed through the electromagnetic induction heating coil 1 based on outputs from the temperature sensor 3 and the operation unit (not shown), a driving operation of the cooling fan 5, and a driving operation of the driving motor 8. To control. The control means 10 controls energization to the electromagnetic induction heating coil 1 by a rice cooking program corresponding to the selected rice cooking menu, and performs a preheating water absorption process, heating to boiling process, boiling maintenance process, cooking process, steaming process, and heat insulation. Perform the process.

The ferrite 2 is rotatably provided below the electromagnetic induction heating coil 1. The ferrite 2 is a magnetic member that partially concentrates the magnetic lines of force from the electromagnetic induction heating coil 1. The ferrite 2 is formed, for example, in a rod shape, and one or a plurality of ferrites 2 are provided. The ferrite 2 is connected and fixed to the ferrite support base 7.
A drive motor 8 is disposed immediately below the ferrite support base 7. The rotation shaft of the drive motor 8 is connected to the ferrite support base 7. As a result, the driving force of the drive motor 8 is transmitted to the ferrite support base 7, and the ferrite support base 7 that supports the ferrite 2 rotates around the center of the bottom surface of the inner hook 6 (center of the electromagnetic induction heating coil 1). Details of the rotational drive of the ferrite 2 will be described later.

  The drive motor 8 corresponds to the “drive means” in the present invention.

Here, the arrangement angle of the ferrite 2 will be described.
FIG. 2 is a diagram for explaining the arrangement angle of the ferrite 2 according to the first embodiment of the present invention.
As shown in FIG. 2, when two ferrites 2 are configured, the center of the bottom surface of the inner pot 6 (the center of the electromagnetic induction heating coil 1) is distributed in the 180 ° direction as the center and is evenly arranged.
For example, when the ferrite 2 is composed of three pieces, the center of the bottom surface of the inner pot 6 (the center of the electromagnetic induction heating coil 1) is distributed at an arrangement angle of 120 ° as a center, and is arranged uniformly. That is, the arrangement angle of the ferrite 2 is 360 / the number of the ferrites 2. In this way, the ferrite 2 is arranged so as to be rotationally symmetric (point symmetric) with the center of the bottom surface of the inner hook 6 (center of the electromagnetic induction heating coil 1) as the rotation center. In addition, you may make it comprise the ferrite 2 by one.

Next, the rice cooking operation of the rice cooker will be described.
FIG. 3 is a diagram showing the transition of the temperature of the inner pot 6 and the electric power supplied to the electromagnetic induction heating coil 1 in the rice cooking process and the heat retaining process of the rice cooker according to Embodiment 1 of the present invention.
The rice cooker was set in the control means 10 when the inner pot 6 containing rice and water to be heated was accommodated in the rice cooker body, the lid 9 was closed and the rice cooker switch was turned on. The rice cooking process is started according to the control program. This rice cooking process has a preheating water absorption process, a heating-boiling process, a boiling maintenance process, a cooking process, and a steaming process, and when this rice cooking process is complete | finished, it transfers to a heat retention process.

  In each step, the control means 10 controls the drive motor 8 to control the rotation speed of the ferrite 2 and the rotation angle and stop time when the ferrite 2 is intermittently rotated. For example, Table 1 shows an example of the rotation speed, the rotation angle, and the stop time when two ferrites 2 are configured and the arrangement angle is 180 °. In addition, the numerical value of Table 1 is an example, and this invention is not limited to this.

  Here, the rotation speed is an angle at which the ferrite 2 rotates per unit time. The rotation angle is an angle from the start of rotational driving of the ferrite 2 to the stop. The stop time is a time during which the drive of the ferrite 2 is stopped when the rotary drive of the ferrite 2 is intermittently performed.

  Hereinafter, each process will be described with reference to FIG. 3 and Table 1.

(Preheating water absorption process)
The preheating water absorption process is a stage before the water in the inner pot 6 boils, and the inner pot 6 is heated at a predetermined temperature for a predetermined time, thereby promoting the water absorption of the rice, and the sugar and umami components as sweet components. This is a step of generating a taste component such as an amino acid.
The control means 10 starts measuring the elapsed time of the preheating and water absorption process, and supplies power to the electromagnetic induction heating coil 1 so that the temperature detected by the kettle temperature detection sensor 3 maintains a predetermined preheating temperature (for example, 55 ° C.). The temperature of the inner pot 6 is adjusted by repeatedly cutting off the power.
And if the elapsed time of the state which maintained the preheating temperature reaches predetermined | prescribed preheating time, the control means 10 will transfer to the following heating-boiling process.

  Here, it is important that water is sufficiently penetrated to the core of the rice in order to make the starch into a delicious rice in the boiling maintenance process to be performed later, but it will enter the boiling maintenance process And since the surface of rice gelatinizes, it becomes difficult to absorb water into the rice. Therefore, it is important to sufficiently absorb water up to the core of the rice in the preheating water absorption process. That is, the deliciousness varies depending on the water absorption in the preheating water absorption process. Moreover, the temperature unevenness in the inner pot 6 in the preheating water absorption process is also an element relating to the deliciousness. If there is temperature unevenness in the inner pot 6 in the preheating water absorption process, there is a possibility that the cooking unevenness will occur when cooked. is there.

  The saccharification enzyme during the preheating water absorption process produces sugar, which is a component of the delicious taste of rice. The temperature range in which this saccharification enzyme works best is about 40 ° C to 60 ° C, especially the temperature at which it is activated. Is set to 55 ° C. to 60 ° C., and it is said that the enzyme is inactivated when the temperature exceeds 60 ° C. If the temperature unevenness of the rice in the inner pot 6 is large, the time for staying in this temperature band varies depending on the location in the inner pot 6, and as a result, the sweetness varies depending on the location. Moreover, since the place which exceeds 60 degreeC may also arise, the part with low sugar content arises depending on the place, and it became the rice with low sugar content as a whole. Thus, it can be seen that it is important to suppress the temperature unevenness in the preheating water absorption process as much as possible in order to cook delicious rice as a whole because the saccharifying enzyme works sufficiently regardless of the location in the inner pot 6. For this reason, in a preheating water absorption process, it is necessary to heat so that the whole may become as uniform as possible.

  For this reason, in the preheating water absorption process, the control means 10 continuously rotates the ferrite 2 at a preset rotation speed. For example, as shown in Table 1, it is preferable that the control unit 10 drives the ferrite 2 to rotate at a rotational speed of about 30 [° / sec] or more and continues to rotate without stopping. For this reason, the magnetic flux concentrated by the ferrite 2 moves sequentially, and the inner pot 6 can be heated uniformly.

(Heating to boiling process)
The heating to boiling process is a process from the end of the preheating water absorption process until the water in the inner pot 6 boils. In the heating to boiling process, the water absorption of rice proceeds rapidly and the gelatinization of rice begins. If the temperature distribution of the objects to be heated (water and rice) in the inner pot 6 is non-uniform, the water absorption state becomes non-uniform, and when cooked, there are hard and soft portions, that is, uneven cooking. In order to cook deliciously, it is important to reduce the temperature unevenness of the to-be-heated object inside the inner pot 6 in the heating to boiling process.

  For this reason, in the heating to boiling step, the control means 10 intermittently drives the ferrite 2 so that the rotation angle from the start of rotation to the stop of rotation becomes a preset angle. For example, as shown in Table 1, the control means 10 causes the ferrite 2 to rotate at a low rotation speed of about 1 to 120 [° / second], a rotation angle of 90, 450 [°], and a stop time of 1 to 30 [second]. It is preferable to intermittently drive the rotation. For this reason, the bottom surface of the inner pot 6 is concentrated and heated by the magnetic flux concentrated by the ferrite 2, and convection occurs in the heated object (rice and water) inside the inner pot 6, thereby stirring the rice and water inside the inner pot 6. It is possible to reduce the temperature unevenness of the heated object inside the inner pot 6. Therefore, it leads to cooking rice deliciously.

  Here, the rotation angle is preferably 180 / number of ferrites 2 + 360 × integer (integer = 0, 1, 2,...). As described above, when a plurality of ferrites 2 are provided, the plurality of ferrites 2 are arranged so as to be rotationally symmetric, and the rotation angle satisfying the above relationship is used to concentrate the magnetic flux due to the ferrites 2. The heated position will have symmetry. For this reason, there is no bias in the concentrated heating position, and the rice and water inside the inner pot 6 can be stirred evenly.

(Boiling maintenance process)
When the water in the inner pot 6 boils, the control means 10 proceeds to the next boiling maintenance step. The boiling process has the effect of making the starch of rice alpha. In this boiling maintenance step, the boiling is maintained by heating the inner pot 6 at a predetermined power for a predetermined time so that the temperature of the heated object becomes a predetermined temperature (for example, 100 ° C.) higher than the temperature at which boiling can be maintained. The water (residual water) remaining without being absorbed by the rice inside the pot 6 is allowed to reach the inner pot 6 uniformly. In this boiling maintenance step, the remaining water is almost not absorbed by the rice, and in this state, the boiling temperature is maintained for a predetermined time, so that gelatinization of rice starch is promoted.

In order to reduce cooking unevenness even in the boiling maintenance step, it is important to reduce temperature unevenness of the heated object inside the inner pot 6.
From this, also in the boiling maintenance step, as in the heating to boiling step, the control means 10 allows the rotation angle of the ferrite 2 from the start of rotation to the rotation stop to be a preset angle. Drive intermittently and rotate. For example, as shown in Table 1, the control means 10 causes the ferrite 2 to rotate at a low rotation speed of about 1 to 120 [° / second], a rotation angle of 90, 450 [°], and a stop time of 1 to 30 [second]. It is preferable to intermittently drive the rotation. For this reason, the bottom surface of the inner pot 6 is centrally heated by the magnetic flux concentrated by the ferrite 2, and the rice and water inside the inner pot 6 in a boiling state can be stirred, thereby reducing temperature unevenness inside the inner pot 6. be able to. Therefore, it leads to cooking rice deliciously.
In addition, in the example of Table 1, although the rotation speed and stop time of a heating-boiling process and a boiling maintenance process were made into the same value, this invention is not restricted to this, It is good also as a different value.

(Cooking process)
When the boiling maintenance process ends, the control means 10 moves to the cooking process. A cooking process is a process for flying off excess water.
When the water in the inner pot 6 runs out, the heat previously consumed by the latent heat of vaporization of water will be used to raise the temperature of the inner pot 6 and the temperature of the inner pot 6 will rise rapidly. This is called dry-up, and when this temperature rise (dry-up) is detected by the pot temperature detection sensor 3, the cooking process is terminated and the process proceeds to the steaming process.

(Steaming process)
After the cooking process, the process proceeds to the steaming process. In the steaming process, the rice is steamed for a predetermined time by heating at a lower heating power than the cooking process, and then the rice cooking process is terminated and the process proceeds to the heat retaining process.

(Heat retention process)
In the heat retaining step, the temperature of the inner pot 6 is maintained at a predetermined temperature so that the temperature of the cooked rice does not decrease.

In the cooking process, the steaming process, and the heat retaining process, water in the inner pot 6 disappears and convection does not occur. For this reason, it is necessary to heat so that the whole is as uniform as possible regardless of the location in the inner pot 6.
Therefore, in the cooking process, the steaming process, and the heat retaining process, the control unit 10 continuously drives the ferrite 2 to rotate at a preset rotation speed. For example, as shown in Table 1, it is preferable that the control unit 10 drives the ferrite 2 to rotate at a rotational speed of about 30 [° / sec] or more and continues to rotate without stopping. For this reason, the magnetic flux concentrated by the ferrite 2 moves sequentially, and the inner pot 6 can be heated uniformly.
In addition, in the example of Table 1, although the rotational speed of the cooking process, the steaming process, and the heat retention process is set to the same value, the present invention is not limited to this and may have different values.

  In the rotational drive of the ferrite 2 in each process, even when the drive motor 8 cannot perform low-speed drive, it is the same as driving at low speed by stopping at a proper rotation angle for a certain time from the rotation drive start position. The effect of can be obtained.

  As described above, in the first embodiment, in the heating to boiling step and the boiling maintaining step, the ferrite 2 is intermittently set so that the rotation angle from the rotation start to the rotation stop becomes a preset angle. Drive to rotate. Moreover, in the preheating water absorption process, the cooking process, the steaming process, and the heat retention process, the ferrite 2 is continuously driven to rotate at a preset rotation speed. For this reason, appropriate heating can be performed according to the state of the article to be heated in each step of cooking rice.

In the first embodiment, the case where the cooling fan 5 is disposed below the heating control board 4 has been described. However, the cooling fan 5 is disposed below the electromagnetic induction heating coil 1 and cooling air is supplied to the electromagnetic induction heating coil 1. Then, cooling air may be supplied to the heating control board 4.
Alternatively, the cooling fan 5 may be provided below the electromagnetic induction heating coil 1 and driven to rotate by the driving force of the drive motor 8 that drives the ferrite 2 to rotate. In this case, the rotational speed of the cooling fan 5 may be made higher than the rotational speed of the ferrite 2 using, for example, a gear. Further, the rotation axis of the cooling fan 5 and the rotation axis of the ferrite 2 may be arranged coaxially. With such a configuration, it is possible to easily prevent overheating of the electromagnetic induction heating coil 1.

Embodiment 2. FIG.
FIG. 4 is a schematic cross-sectional view schematically showing an example of the configuration of the rice cooker according to Embodiment 2 of the present invention.
As shown in FIG. 4, the cooling fan 5 of the rice cooker according to the second embodiment is provided below the electromagnetic induction heating coil 1. The cooling fan 5 is rotationally driven by the driving force of the drive motor 8 that rotationally drives the ferrite 2. For example, by making the rotation axis of the ferrite 2 and the rotation axis of the cooling fan 5 the same, the ferrite 2 and the cooling fan 5 are rotationally driven by the driving force of the drive motor 8. Note that the rotational speed of the cooling fan 5 may be made higher than the rotational speed of the ferrite 2 using, for example, a gear.
Other configurations are the same as those of the first embodiment, and the same reference numerals are given to the same portions.

With such a configuration, the cooling fan 5 can be disposed immediately below the electromagnetic induction heating coil 1, and cooling air that has a large air volume and does not rise in temperature from the cooling fan 5 is supplied to the electromagnetic induction heating coil 1. It is possible to easily prevent overheating of the electromagnetic induction heating coil 1.
In addition, by providing an air path in the direction in which the heating control board 4 is arranged, the heating control board 4 can also be used for cooling.

(Drive control of ferrite 2)
FIG. 5 shows the transition of the temperature of the inner pot 6 in the rice cooking process and the heat retaining process of the rice cooker according to Embodiment 2 of the present invention, the energization power to the electromagnetic induction heating coil 1, and the rotation speed of the cooling fan 5. FIG. 5, in addition to FIG. 3 of the first embodiment, the rotation speed (energization power) of the cooling fan 5 is shown.
As shown in FIG. 5, the cooling fan 5 of the second embodiment sets the number of rotations according to the energization power to the electromagnetic induction heating coil 1. That is, the control means 10 operates the drive motor 8 to rotate the cooling fan 5 when the electromagnetic induction heating coil 1 is energized, and stops the drive motor 8 when the electromagnetic induction heating coil 1 is de-energized. The rotation of the cooling fan 5 is stopped. Further, the control means 10 increases the energization power to the drive motor 8 and increases the rotational speed of the cooling fan 5 as the input power to the electromagnetic induction heating coil 1 is increased.

  The rotational drive of the ferrite 2 in the second embodiment depends on the rotational drive of the cooling fan 5. That is, when the electromagnetic induction heating coil 1 is energized, the ferrite 2 is driven to rotate, and when the energization to the electromagnetic induction heating coil 1 is stopped, the ferrite 2 is stopped from rotating. Moreover, the rotational speed of the ferrite 2 increases as the input power to the electromagnetic induction heating coil 1 increases.

By such an operation, the drive motor 8 that rotationally drives the cooling fan 5 and the ferrite 2 is turned ON / OFF at the ON / OFF control timing of energization to the electromagnetic induction heating coil 1 in each step of the rice cooking process and the heat retaining process. The cooling fan 5 and the ferrite 2 are repeatedly rotated and stopped.
When the energization to the electromagnetic induction heating coil 1 is in the ON state, the position of the magnetic lines of force concentrates right above the ferrite 2, but since the ferrite 2 rotates, the position of the magnetic lines of force generated in the inner hook 6 continues to change.
In addition, when the input power to the electromagnetic induction heating coil 1 is large, the rotational speed of the ferrite 2 is large, so that the changing speed of the position of the magnetic lines generated in the inner hook 6 is increased, and the bottom temperature of the inner pot 6 is uniformly heated. The That is, the inner hook 6 is prevented from being overheated locally. Thereby, when the input power is large and the temperature is likely to rise, the electromagnetic induction heating coil 1 is prevented from being overheated locally.
In addition, when the input power to the electromagnetic induction heating coil 1 is small, the rotational speed of the ferrite 2 is small, so that the change speed of the position of the magnetic lines generated in the inner hook 6 is slow, and a temperature gradient is generated on the bottom surface of the inner hook 6. The heated object inside the inner pot 6 is in a state where it is easy to convect. Thereby, a to-be-heated material (rice, water, etc.) can be heated efficiently.
Note that, when the energization of the electromagnetic induction heating coil 1 is in an OFF state, the rotation of the ferrite 2 stops. However, since no magnetic field lines are generated, the ferrite 2 is not concentratedly heated.

  Thus, in each process of a rice cooking process and a heat retention process, since ON / OFF of energization of the electromagnetic induction heating coil 1 and the magnitude of input electric power differ, control which a convection state changes for every process is attained.

  In the second embodiment, the cooling fan 5 and the ferrite 2 are controlled so as to change the number of revolutions according to the amount of electric power supplied to the electromagnetic induction heating coil 1. You may control by.

  In the second embodiment, the cooling fan 5 and the ferrite 2 are controlled to change the number of revolutions according to the amount of power supplied to the electromagnetic induction heating coil 1. It may be driven at a constant speed regardless of the electric power.

Embodiment 3 FIG.
FIG. 6 is a schematic cross-sectional view schematically showing an example of the configuration of the rice cooker according to Embodiment 3 of the present invention.
FIG. 7 is a schematic plan view schematically showing the configuration of the cooling fan 5 according to Embodiment 3 of the present invention.
As shown in FIGS. 6 and 7, the cooling fan 5 of the rice cooker according to the third embodiment is provided below the electromagnetic induction heating coil 1.
The cooling fan 5 has a plurality of blades 5a, and at least a part of the plurality of blades 5a has magnetic properties.
Other configurations are the same as those of the first embodiment, and the same reference numerals are given to the same portions.
The rotation control of the cooling fan 5 is the same as that in the second embodiment.

  For example, as shown in FIG. 7, three blades 5 a are formed, and one of them is formed of ferrite 2. Note that all of the plurality of blades 5 a may be formed of the ferrite 2. Further, only a part of the single blade 5 a may be formed of the ferrite 2.

Further, for example, the ferrite 2 may be attached to at least a part of the plurality of blades 5a. For example, as shown in FIG. 8, the ferrite 2 may be bonded to the upper surface of the blade 5 a by using an adhesive or a fixing jig.
The attachment position of the ferrite 2 is not limited to this, and the ferrite 2 may be fixed to a part or all of the upper surface or the lower surface of the blade 5a using an adhesive or a fixing jig.

  As described above, in Embodiment 3, since the cooling fan 5 is provided below the electromagnetic induction heating coil 1, the cooling fan 5 can be disposed immediately below the electromagnetic induction heating coil 1. Therefore, it is possible to supply the cooling air whose air volume is large and the temperature is not increased to the electromagnetic induction heating coil 1, and it is possible to easily prevent the electromagnetic induction heating coil 1 from being overheated.

Further, since the blade 5a of the cooling fan 5 provided below the electromagnetic induction heating coil 1 has magnetic characteristics, it is not necessary to separately provide the ferrite 2 to be rotationally driven, thereby reducing the number of parts and manufacturing cost. Therefore, the apparatus can be made compact.
Further, as the cooling fan 5 is driven to rotate, the position of concentrated heating by the blades 5a having magnetic characteristics moves. For this reason, in each process of a rice cooking process and a heat retention process, since ON / OFF of rotation of the cooling fan 5 and the magnitude of a rotation speed differ, control which a convection state changes for every process is attained.

  The configuration of the third embodiment and the configuration of the first embodiment described above may be combined.

  DESCRIPTION OF SYMBOLS 1 Electromagnetic induction heating coil, 2 ferrite, 3 pot temperature detection sensor, 4 heating control board, 5 cooling fan, 5a blade | wing, 6 inner pot, 7 ferrite support stand, 8 drive motor, 9 lid body, 10 control means.

Claims (8)

An induction heating coil;
Control means for controlling the energization to the induction heating coil, a preheating water absorption process, a heating to boiling process, a boiling maintenance process, a cooking process, a steaming process, a heat retaining process,
One or more ferrites rotatably provided below the induction heating coil;
Drive means controlled by the control means to drive the ferrite to rotate;
With
The control means includes
In the heating to boiling step and the boiling maintaining step,
An induction heating cooker, wherein the ferrite is intermittently driven to rotate so that a rotation angle from a rotation start to a rotation stop becomes a preset angle. The control means includes
In the preheating water absorption step, the cooking step, the steaming step, and the heat retention step,
The induction heating cooker according to claim 1, wherein the ferrite is continuously driven to rotate at a preset rotation speed. The arrangement angle of the ferrite is 360 / the number of the ferrites,
The induction heating cooker according to claim 1 or 2, wherein the rotation angle is 180 / the number of the ferrite + 360 x integer. A cooling fan that is provided below the induction heating coil and supplies cooling air to the induction heating coil;
The cooling fan is
The induction heating cooker according to any one of claims 1 to 3, wherein the induction heating cooker is rotationally driven by a driving force of the driving unit that rotationally drives the ferrite. The induction heating cooker according to claim 4, wherein a rotating shaft of the cooling fan and a rotating shaft of the ferrite are arranged coaxially. A cooling fan that is provided below the induction heating coil and supplies cooling air to the induction heating coil;
The cooling fan has a plurality of blades,
The induction heating cooker according to claim 1, wherein at least some of the plurality of blades have magnetic properties. The induction heating cooker according to claim 6, wherein at least some of the plurality of blades are formed of ferrite. The induction heating cooker according to claim 6, wherein ferrite is attached to at least a part of the plurality of blades.

Images