JP5665913B2 - Induction heating cooker - Google Patents

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)

  When heating an object to be heated (rice, water, etc.) put into a kettle or pan with an induction heating cooker, if the magnetic flux is concentrated by a magnetic member (ferrite), the kettle or pan becomes locally hot. Therefore, there is a problem that the induction heating coil is locally heated.

  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.

The present invention has been made to solve the above-described problems, and provides an induction heating cooker that can efficiently heat an object to be heated (rice, water, etc.) placed in a pot or a pan. Is.
Moreover, the induction heating cooking appliance which can make it easy to prevent overheating of an induction heating coil is obtained.
Further, it is possible to obtain an induction heating cooker that can reduce the number of parts and reduce the manufacturing cost, and can achieve the compactness of the apparatus or the simplification of the air path design.

  An induction heating cooker according to the present invention includes an induction heating coil and a cooling fan that is provided below the induction heating coil and supplies cooling air to the induction heating coil. The cooling fan includes a plurality of blades. And at least some of the plurality of blades have magnetic properties.

The present invention can efficiently heat an object to be heated (rice, water, etc.) put in a pot or a pan.
In addition, overheating of the induction heating coil can be easily prevented.
In addition, the number of parts can be reduced to reduce the manufacturing cost, and the apparatus can be made compact or the air path design can be simplified.

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 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, 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 2 of this invention. It is a plane schematic diagram which shows schematically the structure of the cooling fan 5 which concerns on Embodiment 2 of this invention. It is a cross-sectional schematic diagram which shows schematically the structure of the cooling fan 5 which concerns on Embodiment 2 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.

  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.

FIG. 2 is a diagram for explaining the arrangement angle of the ferrite 2 according to the first embodiment of the present invention.
For example, 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. That is, 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.
When a plurality of ferrites 2 are provided in this way, the plurality of ferrites 2 are arranged so as to be rotationally symmetric, so that the position where heat is concentrated by the concentration of magnetic flux by the ferrites 2 has 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. Therefore, the heated object (rice, water, etc.) thrown into the inner pot 6 can be efficiently heated.
In addition, you may make it comprise the ferrite 2 by one.

  In FIG. 1 again, 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).

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

The cooling fan 5 is disposed below the electromagnetic induction heating coil 1 and supplies cooling air to the electromagnetic induction heating coil 1. The cooling fan 5 is rotationally driven by the driving force of the driving 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.
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. That is, the cooling air supplied from the cooling fan 5 may be supplied to the heating control board 4 after cooling the electromagnetic induction heating coil 1.

  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.

(Drive control of ferrite 2)
FIG. 3 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 the first embodiment of the present invention, the energization power to the electromagnetic induction heating coil 1, and the rotational speed of the cooling fan 5. FIG.
As shown in FIG. 3, the cooling fan 5 of the first 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 first 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 magnitude of input electric power differ, the temperature distribution of the inner pot 6 bottom surface temperature changes for every process. Control becomes possible.

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

  In the first 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. It may be driven at a constant speed regardless of the electric power.

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.
FIG. 5 is a schematic plan view schematically showing the configuration of the cooling fan 5 according to Embodiment 2 of the present invention.
As shown in FIGS. 4 and 5, 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 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 first embodiment.

  For example, as shown in FIG. 5, 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. 6, the ferrite 2 may be bonded to the upper surface of the blade 5a or fixed using 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 the second embodiment, 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.
Moreover, since the number of parts can be reduced, the degree of freedom of the position where the air passage is provided is improved, and the air passage design can be simplified.

  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 the temperature distribution of the inner pot 6 bottom temperature changes for every process is possible. It becomes.

  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 (5)

An induction heating coil;
A cooling fan which is provided below the induction heating coil and supplies cooling air to the induction heating coil;
With
The cooling fan has a plurality of blades,
An induction heating cooker, wherein at least some of the plurality of blades have magnetic properties. The induction heating cooker according to claim 1, wherein at least some of the plurality of blades are formed of ferrite. The induction heating cooker according to claim 1 or 2, wherein ferrite is attached to at least a part of the plurality of blades. Control means for controlling the rotational drive of the cooling fan;
The control means includes
When the induction heating coil is energized, the cooling fan is rotationally driven,
The induction heating cooker according to any one of claims 1 to 3, wherein the rotation of the cooling fan is stopped when energization of the induction heating coil is stopped. The control means includes
The induction heating cooker according to claim 4, wherein the rotation speed of the cooling fan is increased as the electric power supplied to the induction heating coil is increased.

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