JP2012010720A - rice cooker - Google Patents

Abstract

An object of the present invention is to provide an inexpensive electromagnetic wave leakage reduction structure that can reduce electromagnetic wave leakage from a rice cooker by mixing or applying an electromagnetic wave shielding material or the like to an inner case that houses an inner pot. To do.
A container main body, a lid member above the container main body, an inner case provided in the container main body, an inner pot accommodated in the inner case, and an electromagnetic induction provided below the inner case. A rice cooker having a coil, wherein the inner case is mixed or coated with a particulate electromagnetic shielding material or an electromagnetic shielding material made of a metal piece to reduce leakage of electromagnetic waves.
[Selection] Figure 1

Description

  The present invention relates to a rice cooker that uses an electromagnetic induction coil as a heating means, and particularly relates to a rice cooker that reduces the amount of leakage of electromagnetic waves caused by electromagnetic induction heating to the outside.

  Modern rice cookers have many useful functions. For example, an induction heating method comprising an electromagnetic induction coil or the like as a heating means is one of them, and a product that is very convenient to use such as efficient rice cooking control and accurate heat retention control over a long time thereafter. It has become one of the.

  By the way, a rice cooker that employs an induction heating method consisting of an electromagnetic induction coil as a heating means can perform precise rice cooking control and accurate heat retention control over a long time, but minute electromagnetic waves leak to the outside. May adversely affect other devices. For this reason, regulations have been established in Japan and overseas to prevent such harmful effects, and each product is required to have an electromagnetic wave leakage amount within the regulations, and various technologies have already been proposed for this purpose. Yes.

  One such technique is shown in FIG. As shown in the figure, this rice cooker is composed of a container main body a and a lid member b that can be opened and closed with respect to the container main body a. The container main body a forms an outer case c and an inner wall. Inner case d, outer case c, shoulder member e for connecting inner case d, and a bottom member f connected to outer case c to form an outer bottom wall, etc. An inner pot g for cooking the contents is stored and arranged.

  Further, an electromagnetic induction coil comprising a bottom coil h and a corner coil i is provided below the inner case d. When cooking, rice or the like is put in the inner pot g and set in the inner case d, and the temperature sensor j is set. The electromagnetic induction coil is turned on to enable energization of the high frequency power source. When a high frequency power supply is energized, a strong magnetic field is generated, and this magnetic field generates eddy currents near the outer surface of the inner pot g made of stainless steel having a large skin resistance, and further generates Joule heat due to the eddy currents. The inner pot g is heated by the Joule heat, and the contents are cooked.

  In this example, a shielding plate k that shields electromagnetic waves is disposed between the electromagnetic induction coil consisting of the bottom coil h and the corner coil i and the outer case c, and the shielding plate k is attached by a plurality of screws m. It is fixed to the inner case d and prevents electromagnetic waves generated by the electromagnetic induction coil from leaking to the outside.

  However, the conventional electromagnetic wave leakage reduction structure requires a new part such as the shielding plate k and the mounting screw m, or requires a mounting operation with the shielding plate k and the screw m, and thus the production cost increases accordingly. In addition, it is necessary to secure the mounting location of the shielding plate k, and in some cases, the rice cooker has to be enlarged to secure the mounting location.

Japanese Patent Publication No. 7-83732

  An object of the present invention is to provide an inexpensive electromagnetic wave leakage reduction structure that can reduce electromagnetic wave leakage from a rice cooker by mixing or applying an electromagnetic wave absorbing material or the like to an inner case that houses an inner pot. It is.

  In order to achieve the above object, the present invention adopts the following configuration.

  In the invention which concerns on Claim 1, a container main body, the cover member above the said container main body, the inner case provided in the said container main body, the inner pot accommodated in the said inner case, and the lower side of the said inner case A rice cooker having an electromagnetic induction coil provided, wherein an electromagnetic wave absorbing material or an electromagnetic wave shielding material is mixed or applied to the inner case.

  In the invention which concerns on Claim 2, the said electromagnetic wave absorber is the structure of the bead shape which included the carbon microcoil.

  In the invention according to claim 3, the electromagnetic wave absorbing material or the electromagnetic wave shielding material is configured to reduce leakage of 20 kHz or less and 50 kHz or more excluding the output frequency band of the electromagnetic induction coil.

  In the invention which concerns on Claim 4, the structure which provides an unevenness | corrugation in the surface of the said inner case.

  In the invention according to claim 1, an electromagnetic wave absorbing material, for example, powder or particulate material, or an electromagnetic wave shielding material, for example, metal powder or a small piece of metal, is mixed into the inner case by integral molding or mixed with a paint. The amount of leakage of electromagnetic waves from the rice cooker can be reduced by applying and the increase in production cost can be suppressed as compared with the electromagnetic wave leakage reduction structure using the conventional shielding plate.

  Further, by using a particulate material as the electromagnetic wave absorbing material or a small piece of metal as the electromagnetic wave shielding material, minute irregularities are formed on the inner case surface, and the surface area of the electromagnetic wave absorbing material or the electromagnetic wave shielding material is increased accordingly. As a result, the amount of leakage of electromagnetic waves can be further reduced.

  Furthermore, the electromagnetic wave absorbing material converts electromagnetic waves into heat energy. By providing such an electromagnetic wave absorbing material in the inner case, the inner case can be warmed, and heat radiation from the inner pot to the outside can be reduced. In particular, it can contribute to energy saving during the heat insulation process.

  In the invention which concerns on Claim 2, while making the electromagnetic wave absorber into the bead-like thing which included the carbon microcoil, while the amount of electromagnetic waves leaked from a rice cooker can be reduced more, it is minute on the inner case surface. Since the bead-shaped irregularities are formed and the surface area of the electromagnetic wave absorbing material can be increased correspondingly, the leakage amount of electromagnetic waves can be further reduced. Also, the carbon microcoil converts electromagnetic waves into heat energy, and by providing such an item in the inner case, the inner case is warmed so that heat radiation from the inner pot to the outside can be reduced. In particular, it can contribute to energy saving during the heat insulation process.

  In the invention according to claim 3, the electromagnetic wave absorbing material or the electromagnetic wave shielding material is reduced to 20 kHz or less and 50 kHz or more excluding the output frequency band of the electromagnetic induction coil without inhibiting the cooking of rice during cooking, Unnecessary leakage of electromagnetic waves can be reduced intensively.

  In the invention according to claim 4, the surface of the inner case is provided with irregularities such as a plurality of dimples and engraved letters, etc., so that the tsuyu and oneva that flowed between the inner case and the outer periphery of the inner pot It is possible to prevent wetting and flowing out of the soot and oneva from flowing through the inner surface of the inner case and outflowing into the container body from the sensor through hole provided at the bottom center of the inner case.

Whole sectional view of the rice cooker of the present invention The top view which shows the state which provided the unevenness | corrugation of the dimple in the inner case of this invention The top view which shows the state which provided the unevenness | corrugation of the character in the inner case of this invention Schematic cross section of one bead-shaped carbon microcoil Sectional drawing of the rice cooker of a prior art example.

  FIG. 1 shows a cross-sectional view in which the present invention is applied to a rice cooker, FIGS. 2 and 3 show a plan view showing a state in which the inner case is provided with dimples or irregularities of letters, and FIG. 4 shows one bead. A schematic cross-sectional view of a carbon carbon coil having a shape is shown.

  As shown in FIG. 1, the rice cooker 1 roughly includes a container main body 2 and a lid member 3 provided above the container main body 2. The lid member 3 is made of resin such as polypropylene (PP) and has an upper member 4, a lower member 5, and an inner cover 6. A heat insulating material 7 is provided in the internal space formed between the upper member 4 and the lower member 5.

  Further, a pressure adjusting lid 8 is provided at the center of the lid member 3. A valve member 9 is provided in the pressure regulating lid 8, and when the internal pressure becomes a predetermined level or higher, the valve member 9 is released, and the steam inside the pressure regulating lid 8 is steamed through a steam passage 10 formed in the pressure regulating lid 8. Release from the mouth 11 to the outside. Further, on the rear side of the lid member 3, a hinge mechanism 12 having a known spring material is provided, and the lid member 3 is locked or unlocked by locking the lock member 13 provided on the upper front side of the rice cooker 1. Is openable and closable with respect to the container body 2.

  The container body 2 includes an outer case 15 that forms an outer wall, an inner case 16 that is in the outer case 15 and forms an inner wall, a shoulder member 17 that forms the upper ends of the inner and outer cases 15 and 16, and the rice cooker 1. It has a bottom member 18 that forms the bottom.

  The outer case 15 is made of a metal such as stainless steel and has a cylindrical shape with upper and lower openings, and forms a body portion of the rice cooker 1. The shoulder member 17 is made of resin or the like, and forms the upper end portion of the container body 2, the hinge mechanism 12 is provided on the rear side thereof, and the handle 19 is provided on the outer peripheral side portion thereof.

  The inner case 16 that forms the inner wall of the container body 2 has a W-shape that is substantially the same shape as the inner pot 25, and a protruding portion 20 that protrudes upward is formed at the center of the bottom, and the center of the protruding portion 20 is further formed. Is provided with a sensor through hole 22 through which the temperature sensor 21 protrudes.

  Further, a ring-shaped heat retaining heater 23 is attached to the outer periphery of the inner case 16 with an aluminum sheet, and the inner pot 25 housed inside is warmed from the side. The outer case 15 and the inner case 16 are firmly connected and fixed to the shoulder member 17 by a forcible fitting means using a locking piece and a locking groove (not shown) and a screw (not shown). The inner case 16 is mixed or coated with an electromagnetic wave leakage reducing material, which is a main part of the present invention. Details will be described later.

  The bottom member 18 that forms the bottom of the rice cooker 1 is formed of a resin similar to the inner case 16 and is attached to the outer case 15 by a forcible fitting means using a locking piece and a locking groove (not shown). A plurality of intake ports 24 are provided on the front side, and an exhaust port (not shown) is provided on the rear side.

  An inner pot 25 is accommodated in the inner case 16. The inner pot 25 is made of iron, magnetic stainless steel, or the like made of a high magnetic material in which the eddy current induced in the interior is large, or the whole is made of earthen pot, and the bottom of the magnetic induction coil hits the bottom. Only a magnetic stainless steel having a large skin resistance, or one formed by welding iron can be used.

  The whole has a W-shaped cross section similar to that of the inner case 16, and when the inner pot 25 is stored in the inner case 16, the center bottom surface of the inner pot 25 is formed at the center of the bottom of the inner case 16. The top of the temperature sensor 21 protruding through the through hole 22 is pressed. Then, the temperature sensor 21 is pushed down, energizes the control circuit, and enables heating control of the rice cooker 1. That is, it is set so that heating control is not performed unless the inner pot 25 is housed in the inner case 16.

  The temperature sensor 21 is a known thermistor that detects the temperature of the inner pot 25 that detects the set state of the inner pot 25. An inner pot 25 containing contents such as rice is stored in the inner case 16, the upper opening thereof is closed by the lid member 3, and induction heating by an electromagnetic induction coil is performed.

  An electromagnetic induction coil including a bottom coil 26 and a corner coil 27 is disposed on the bottom and side portions of the inner case 16, respectively. The bottom coil 26 and the corner coil 27 are fixed by a coil base 28.

  An operation panel 29 is provided on the upper front side of the rice cooker 1, and an operation board 32 on which various switch buttons 30, a display device 31 and the like are arranged is attached near the lower portion of the operation panel 29.

  Moreover, the power supply board 33 is attached to the front lower side of the rice cooker 1 in the form of standing. Various electronic circuit elements such as a power transistor (IGBT) and various drive circuits necessary for induction heating are attached to the power supply substrate 33. These various electronic circuit elements include elements that generate heat, such as the IGBT described above. Therefore, the power supply board 33 is provided with a cooling fin 34 as a heat sink for assisting heat dissipation of these heating elements and a cooling fan 35 for cooling the cooling fin 34.

  The bottom coil 26, the corner coil 27, and the heat retaining heater 23 are controlled by these operating devices and various electronic circuit elements, and optimal rice cooking and heat retaining control are performed. The cooling fan 35 is for maintaining various electronic circuit elements and the like at an optimum temperature. The cooling fan 35 sucks air from an intake port 24 provided in front of the bottom member 18 and below the cooling fan 35, The electromagnetic induction coil including the power supply substrate 33, the bottom coil 26, and the corner coil 27 is cooled.

  By the way, when electromagnetic induction heating is performed by the electromagnetic induction coil including the bottom coil 26 and the corner coil 27, there is a problem that electromagnetic waves are inevitably leaked to the outside. Each product is provided with appropriate measures such as providing the means shown in FIG.

  The present invention provides an electromagnetic leakage reduction structure that is simpler and less expensive than the conventional one. Specifically, when the inner case 16 is formed, the electromagnetic wave leakage reducing structure of the present invention is formed by mixing the material of the inner case 16 with an electromagnetic wave absorbing material or an electromagnetic wave shielding material, and forming the electromagnetic wave absorbing material or the inner case 16 in the inner case 16. An electromagnetic wave shielding material is mixed, or after the inner case 16 is molded, a paint mixed with an electromagnetic wave absorbing material or an electromagnetic wave shielding material is applied to the surface of the inner case 16. In addition, after shaping | molding the inner case 16, you may stick the sheet | seat of an electromagnetic wave absorber or an electromagnetic wave shielding material on the surface of the inner case 16, etc.

  As the electromagnetic wave absorber, for example, carbon powder, fiber, ferrite, or the like can be used. The electromagnetic wave absorbing material has a function of absorbing electromagnetic waves by converting them into heat energy and reducing leakage to the outside. The electromagnetic wave absorbing material can be easily mixed into the inner case 16 or applied to the surface. In addition, due to the inexpensive structure, leakage of electromagnetic waves to the outside can be reduced, and the inner case 16 is warmed by the converted heat energy, so that the heat retention efficiency is improved especially in the heat retention process of the rice cooker, and energy saving is achieved. To be able to contribute.

  In addition, when an electromagnetic wave absorbing material in the form of particles is used, a large number of irregularities are formed on the surface of the inner case 16 and the surface area of the entire electromagnetic wave absorbing material is increased. As a result, the electromagnetic wave absorbing effect of the electromagnetic wave absorbing material is increased. It will become higher.

  For example, metal powder can be used as the electromagnetic shielding material. The electromagnetic wave shielding material has a function of reflecting electromagnetic waves and reducing leakage to the outside. Like the electromagnetic wave absorbing material, the electromagnetic wave shielding material is mixed in the inner case 16 or applied to the surface. With this simple and inexpensive structure, leakage of electromagnetic waves to the outside can be reduced.

  Further, when a small piece of metal that is finely crushed is used as the electromagnetic shielding material, a large number of irregularities are formed on the surface of the inner case 16, and the surface area of the entire electromagnetic shielding material is increased. As a result, the electromagnetic shielding material As a result, the electromagnetic shielding effect increases.

  By the way, as an electromagnetic wave absorbing material, a bead-like material having a diameter of less than 1 mm (hereinafter referred to as CMC beads) containing carbon microcoil (CMC) 41 (manufactured by CMC Technology Development Co., Ltd.) is known. As shown in the schematic cross-sectional view of FIG. 4, this CMC bead 40 is formed by wrapping a plurality of small coil-like carbon fibers having a diameter of several microns in an acrylic plastic resin (PMMA). .

  Since the CMC 41 is a conductive coil, the CMC 41 itself constitutes an LCR resonance circuit, and has a function of resonating with an electromagnetic wave and efficiently converting the electromagnetic wave into heat energy.

  The simple and inexpensive structure in which the CMC beads 40 are mixed in the inner case 16 or applied to the surface can reduce the leakage of electromagnetic waves to the outside more reliably, and the converted thermal energy Since the inner case 16 is warmed, the heat retention efficiency of the rice cooker 1 particularly in the heat retaining step can be further improved. The CMC beads 40 are in the form of particles, and a large number of irregularities are formed on the surface of the inner case 16, thereby increasing the surface area of the entire electromagnetic wave absorbing material and further enhancing the electromagnetic wave absorbing effect.

  The CMC beads 40 as well as the electromagnetic wave absorbing material or the electromagnetic wave shielding material can be designed as an electromagnetic wave absorber that sets a target frequency or frequency band. Moreover, generally the output frequency band of the electromagnetic induction coil of the rice cooker 1 is 20 kHz to 50 kHz.

  This inventor makes the rice-cooking heating capacity of the rice cooker 1 by setting the electromagnetic wave absorption frequency band of the electromagnetic wave absorbing material or the electromagnetic wave shielding material to 20 kHz or less and 50 kHz or more other than the output frequency band of the electromagnetic induction coil of the rice cooker 1. It was found that leakage of electromagnetic waves in other frequency bands to the outside can be reduced without lowering.

  By the way, when cooking with the rice cooker 1, the soup and oneba may spill out from the inner pot 25. Then, there is a risk of flowing out from the sensor through hole 22 provided in the center of the bottom to the temperature sensor 21 in the container body 2.

  By forming the protruding portion 20 protruding upward at the inner peripheral end portion of the sensor through-hole 22 of the inner case 16, it is possible to prevent to some extent that tsuyu and oneva are discharged from the sensor through-hole 22. However, if the amount of spillage of tsuyu or oneba increases, there may be cases where the protrusions 20 alone are not sufficient. Even in such a case, an example will be described below in which it is possible to prevent the leakage of the soot and oneva from the sensor through hole 22 and further reduce the leakage amount of the electromagnetic wave.

  The thing of FIG. 2 provides the some dimple 45 from the side part of the inner case 16 to a bottom part. The dimples 45 are circular and have a diameter that is larger toward the side and a diameter that is smaller toward the bottom, but may be reversed.

  Further, the dimple 45 may be a concave shape that is recessed from the top to the bottom, or a convex shape that protrudes from the bottom to the top. The convex shape reduces clogging and down on the surface to reduce downstream outflow.

  In this case, the convex shape must be provided, for example, in a ring shape and arranged with a small interval between adjacent ones, and the number thereof is inevitably increased. The number and size can be varied in a variety of ways, because it is possible to store Tsuyu and Oneva. Further, in the case of a concave shape, the larger the area of the hole at the bottom than the side portion of the inner case 16, the greater the effect of accumulating tsuyu and oneva in that, so the arrangement opposite to that in FIG. It is preferable to arrange a small diameter so that the diameter increases toward the bottom.

  Even in the example of FIG. 2, the inner case 16 is mixed or coated with an electromagnetic wave absorbing material or an electromagnetic wave shielding material. Then, the electromagnetic wave absorbing material or the electromagnetic wave shielding material is also mixed or applied to the uneven surface of the inner case 16. As a result, the surface area of the electromagnetic wave absorbing material or the electromagnetic wave shielding material is further increased, and as a result, the electromagnetic wave absorbing effect or the electromagnetic wave shielding effect is further increased.

  FIG. 3 shows another example. The thing of FIG. 3 provides the character 50 from the side part of the inner case 16 to a bottom part. The character 50 is a reminder or the like, and may be a concave shape that is recessed from the top to the bottom, or a convex shape that protrudes from the bottom to the top. Oneva is collected to reduce the outflow to the downstream, and the convex one dams down the bush and oneba on its surface to reduce the outflow to the downstream.

  In the case of the character 50, a convex shape is not sufficient, but a concave shape is better. The character may be other than that shown in FIG. 3, may be a framed character, and may be other than a character, for example, a pattern, a brand mark, or the like.

  Even in the example of FIG. 3, the inner case 16 is mixed or coated with an electromagnetic wave absorbing material or an electromagnetic wave shielding material. Then, the electromagnetic wave absorbing material or the electromagnetic wave shielding material is also mixed or applied to the uneven surface of the inner case 16. As a result, the surface area of the electromagnetic wave absorbing material or the electromagnetic wave shielding material is increased as in FIG. 2, and as a result, the electromagnetic wave absorbing effect or the electromagnetic wave shielding effect is further increased.

  It is important that the dimple 45 and the character 50 shown in FIGS. 2 and 3, and further, the handle, the brand mark, etc. are provided at least on the bottom of the inner case 16. By providing it at the bottom of the inner case 16, the effect can be enhanced.

  As another example, unevenness may be formed on the surface of the inner case 16 by mixing hollow glass particles having an air layer with the material of the inner case 16. In the case of this example, the heat insulation effect can be enhanced by the air layer of glass particles. Also in this case, the surface area of the electromagnetic wave absorbing material or the electromagnetic wave shielding material can be increased, and as a result, the electromagnetic wave absorbing effect or the electromagnetic wave shielding effect can be further enhanced.

  The present invention is not limited to the configuration of the above embodiment, and can be appropriately changed in design without departing from the gist of the invention. For example, the dimple 45 and the character 50 have been described as means for providing irregularities. Any material may be used as long as it is uneven.

DESCRIPTION OF SYMBOLS 1 Rice cooker 2 Container body 3 Lid member 4 Upper member 5 Lower member 6 Inner cover 7 Heat insulating material 8 Pressure regulating lid 9 Valve member 10 Steam passage 11 Steam port 12 Hinge mechanism 13 Lock member 15 Outer case 16 Inner case 17 Shoulder member 18 Bottom member 19 Handle 20 Protruding portion 21 Temperature sensor 22 Sensor through-hole 23 Insulating heater 24 Intake port 25 Inner pan 26 Bottom coil 27 Corner coil 28 Coil base 29 Operation panel 30 Switch button 31 Display device 32 Operation board 33 Power supply board 34 Cooling fin 35 Cooling fan 40 CMC beads 41 CMC
45 dimples 50 characters

Claims (4)

A container main body, a lid member above the container main body, an inner case provided in the container main body, an inner pot accommodated in the inner case, and an electromagnetic induction coil provided below the inner case. A rice cooker,
A rice cooker characterized in that an electromagnetic wave absorbing material or an electromagnetic wave shielding material is mixed or applied to the inner case.   2. The rice cooker according to claim 1, wherein the electromagnetic wave absorbing material is in the form of beads including carbon microcoils.   The rice cooker according to claim 1 or 2, wherein the electromagnetic wave absorbing material or the electromagnetic wave shielding material reduces leakage of 20 kHz or less and 50 kHz or more excluding an output frequency band of the electromagnetic induction coil.   The rice cooker according to any one of claims 1 to 3, wherein unevenness is provided on a surface of the inner case.

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