JP2002119415A - Rice cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rice cooker excellent in opening-closing operability of a cover body and capable of sufficiently heating an upper part of the cooker, and to prevent an adverse influence on other apparatus such as a television by reducing a magnetic field leaking from the cover body for arranging a heating source on the upper part of the cooker. SOLUTION: An upper part of a rice cooker body for housing the iron pot 13 is covered with the cover body 16 so as to be freely openable-closable. The cover body 16 has a cover induction heating coil 22 arranging a heating plate 21 on the under surface and inductively heating the heating plate 21 on the inside. A magnetism preventive material 34 is arranged above the cover induction heating coil 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rice cooker in which a lid is provided with a heating source for heating an upper portion of a pot.

[0002]

2. Description of the Related Art In order to cook delicious rice, rice cookers which can heat not only the lower part but also the upper part of the kettle have become mainstream.

A rice cooker of the type in which the upper part of the pot is heated is described in, for example, Japanese Utility Model Application No. 51-140744 (Japanese Utility Model Application Laid-Open No.
No. 871). As shown in FIG. 8, this rice cooker has a configuration in which an upper portion of a pot 1 is opened and closed by a lid 2. Further, a lid case 4 having a lid induction heating coil 3 is placed on the upper portion of the lid 2, and the lid 2 is induction-heated by the lid induction heating coil 3 to heat the upper portion of the pot 1.

However, when removing the cooked rice from the pot 1, the lid case 4 must be removed, and the lid 2 heated and heated to a high temperature must be removed from the pot 1. There is a danger of burns. Further, since the lid 2 is hot, it is necessary to pay attention to the place where the removed lid 2 is placed, and the removal operation of the lid 2 is troublesome. Was.

For example, there is a rice cooker disclosed in Japanese Patent Laid-Open No. 6-105740. This rice cooker will be described with reference to FIG.

[0006] As shown in the figure, a lid 7 is attached to the top of a rice cooker body 6 in which a pot 5 is stored so as to be openable and closable. The lid 4 has an outer frame formed by an outer lid cover 8, and a lower part of the lid 7 opposed to an upper part of the shuttle 5 is formed by a lower cover 9. A lid induction heating coil 10 is provided in the lid 7, and has a structure for induction heating an inner lid 11 detachably attached to the lower cover 9 side of the lid 7.

As described above, the lid induction heating coil 10 is disposed in the lid 7 and the inner lid 11 on the lower surface side of the lid 7 is induction-heated to open and close the lid 7. The outer frame side of the lid 7, that is, the outer lid cover 8 is prevented from becoming high temperature, and the opening and closing operation of the lid 7 is simplified.

[0008]

However, the rice cooker described above has a structure in which the inner lid 11 is induction-heated by the lid induction heating coil 10 and the upper part of the pot 5 is heated, so that the lid induction heating coil 10 and the inner lid 11 are heated. , The inner lid 11 could not be sufficiently induction-heated, and the steam above the kettle 5 could not be sufficiently blown off.

In order to solve the above problem, it is conceivable to increase the size of the lid induction heating coil 10 to increase the induction heating capability. In this case, however, the weight of the lid induction heating coil 10 increases, and the opening and closing operation of the lid 7 is required. However, there has been a problem that the opening / closing operability is deteriorated.

In view of the above problems, the present invention provides a rice cooker capable of sufficiently heating the upper portion of a pot while improving the opening and closing operability of the lid, reducing the magnetic field leaking from the lid, and providing a television. The purpose is to prevent adverse effects on devices such as.

[0011]

According to the present invention, in order to achieve the above object, an upper portion of a rice cooker body accommodating a pot is openably and closably covered by a lid, and the lid is provided with a heat generating portion on a lower surface thereof. In addition, a lid induction heating coil for inductively heating the heat generating portion is provided therein, and a magnetic shield is provided above the lid induction heating coil.

Thus, it is possible to provide a rice cooker capable of sufficiently heating the upper part of the pot while improving the opening and closing operability of the lid, and to reduce the magnetic field leaking from the lid. It is possible to prevent a device such as a television from being adversely affected.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention comprises a rice cooker main body for accommodating a kettle, and a lid for opening and closing an upper portion of the rice cooker main body, wherein the lid is A heat-generating part is provided on the lower surface thereof, and a lid induction heating coil for induction-heating the heat-generating part is provided inside the heat-generating part, and a magnetic shield is provided above the lid induction heating coil. The heating part on the lower surface of the lid is induction-heated, and the upper part of the pot can be heated by the heat from the heating part. The lid induction heating coil is arranged inside the lid, and the lid induction heating coil and the heating Since the distance to the section can be set small, the heating section can be sufficiently induction-heated, and the upper portion of the pot can be sufficiently heated. In addition, since it is not necessary to increase the size of the lid induction heating coil in order to obtain a sufficient heating amount, the lid is not heavy and does not hinder the opening and closing operation, and the opening and closing operability of the lid can be improved. it can. In addition, by disposing a magnetic shielding material above the lid induction heating coil, the magnetic field directed upward from the lid induction heating coil can be shielded by the magnetic shielding material, and the magnetic field can be prevented from leaking out of the lid. , Such as a television.

According to a second aspect of the present invention, in the first aspect of the present invention, the lid induction heating coil is formed in a ring shape, and a steam hole is provided in the ring-shaped opening. The high temperature portion of the heat generating portion facing the lid induction heating coil has a ring shape, and the heat of the ring high temperature portion of the heat generating portion is transmitted to the center and outside of the ring shape.
At this time, since much heat is transmitted from the high-temperature portion of the heat-generating portion to the central portion, the central portion is more likely to be heated, and the steam holes provided at the central portion are sufficiently heated, and the temperature of the steam holes is increased. The lowering of the temperature of the upper part of the shuttle due to the lowering can be prevented.

[0015]

(Embodiment 1) A first embodiment of the present invention will be described below with reference to FIGS. First, the overall configuration of the rice cooker according to the present embodiment will be described with reference to FIG. In FIG. 1, reference numeral 12 denotes a rice cooker main body, which forms a kettle accommodating portion 14 for accommodating a kettle 13 therein. The hinge 1 is located at the upper rear of the rice cooker body 12.
5 and a lid 16 which can be opened and closed around the hinge 15.
Is installed. The lid 16 is located above the rice cooker main body 12 so as to cover the upper part of the pot 13. The shuttle 13 has a structure in which the bottom is induction-heated by induction heating coils 17 and 18, and the side is heated by a heater 19 wound around the outer periphery of the side surface of the shuttle accommodating portion 14.

The lid 16 has an outer frame formed by an outer lid cover 20 and a lower surface on the side of the shuttle 13 formed by a heating plate 21.
Inside, a lid induction heating coil 22 is provided. The lid induction heating coil 22 is for induction heating the lower heating plate 21, and the heating plate 21 is made of a material to be induction-heated, a magnetic material such as stainless steel, etc., and constitutes a heating part that generates heat by induction heating. It is. In the lid 16, a heat insulating material 23 is disposed above the lid induction heating coil 22, and a steam hole 24 for guiding the water vapor above the pot 13 to the outside is penetrated in the vertical direction of the lid 16.

Next, the structure around the lid will be described with reference to FIG. As shown in the figure, an abnormal temperature sensor 25 and a lid temperature sensor 26 are attached to the heating plate 21 in close contact with each other. The abnormal temperature sensor 25 is provided below the lid induction heating coil 22 so that the magnetic field of the lid induction heating coil 22 is reduced. To be easily received and induction-heated, so that an abnormal temperature rise of the heating plate 22 can be quickly detected. When the abnormal temperature rise is detected, the induction heating by the lid induction heating coil 22 is stopped. ing. On the other hand, the lid temperature sensor 26 is disposed on the steam hole side,
In order to be able to detect the temperature of the steam generated in the upper portion of the lid, the lid is disposed at a position that is hardly affected by the magnetic field of the induction heating coil 22.

An annular packing 27 having a U-shaped cross section is provided on the outer peripheral side of the heating plate 21, and the entire lower end of the annular packing 27 is in close contact with the entire upper surface of the flange portion 28 above the shuttle 13. The contact prevents the water vapor generated at the upper portion of the pot 13 from leaking to the outside, and also prevents the water vapor from entering the lid 16. The annular packing 27 is attached to the lid 16.
Between the outer lid cover 20 and the heat generating plate 21.

Next, a detailed configuration of the lid induction heating coil will be described with reference to FIG. As shown in the figure, the lid induction heating coil 22 has a ring-shaped flat surface, and the ring-shaped lid induction heating coil 22 is placed in the coil housing portion 30 of the flame-retardant coil support base 29 shown in FIG. And is covered with a flame-retardant material injected into the coil housing portion 30, for example, a flame-retardant silicon 31.

The ferrite 3 is provided above the coil housing 30.
A ferrite support part 33 for supporting the ferrite 32 is provided, and the ferrite 32 can be temporarily fixed on the upper part of the coil support base 29. Fix the ferrite 32 with flame-retardant silicon 3
By injecting 1 into the coil housing 31, the ferrite 32 can be easily fixed on the coil support 29.

The ferrites 32 are arranged radially as shown in FIG. 3 and deflect the direction of the magnetic field generated from the lid induction heating coil 22 so that the upwardly directed magnetic field is as low as possible on the heating plate 21 side. It is to go to. Although the ferrite 32 is temporarily fixed to the ferrite support portion 33 of the coil support 29, the lid induction heating coil 22 and the ferrite 32 are both covered with a flame-retardant material, and both are fixed. The coil support 29 can be easily assembled in this case.

Furthermore, if the coil support base in which the lid induction heating coil and the ferrite are buried is made of a flame-retardant material, there is no need to mount an induction heating coil or the like on the coil support base, and the assemblability is greatly improved. Can be enhanced.

Although the above-described ferrite 32 can reduce the amount of the magnetic field going upward from the lid induction heating coil 22, a part of the magnetic field may leak from the upper portion of the lid 16 to the outside. If this magnetic field leaks to the outside, it adversely affects devices such as televisions. Therefore, as shown in FIG. 2, a magnetic shield 34 is provided above the ferrite 22. The magnetic shield 34 is formed in a ring shape that covers substantially the entire upper surface of the lid induction heating coil 22, and the outer peripheral portion is fixed to the outer peripheral flange 35 of the coil support base 29 with screws 36. The magnetic shield 34 is formed of a material that can shield a magnetic field, for example, an aluminum plate, shields a magnetic field leaking above the lid induction heating coil 22, and prevents a magnetic field from leaking outside the lid 16. .

Next, the mounting structure of the lid induction heating coil 22 will be described with reference to FIG. As shown in the figure, the lid induction heating coil 22 is housed in the coil housing 30 of the coil support base 29, and the ferrite 32 is placed on the ferrite support 33, and the flame-retardant silicon is placed in the coil housing 30. Then, the lid induction heating coil 22 and the ferrite 32 are fixed to the coil support base. A ring-shaped magnetic shield 34 is fixed to the flange 35 by screws 36 above the coil support base 29. Further, a mounting portion 37 is provided on the outer peripheral portion of the coil support base 22 so as to extend from the flange portion 35 to the outer circumference, and the mounting portion 37 is fixed to the outer cover by screws.

As shown in FIG. 3, the mounting portion 37 is formed at a plurality of positions on the coil support base 29 and overlaps with the mounting portion of the heat generating plate 21 to be mounted on the outer lid cover 20 and is screwed to the coil supporting base 29 and the heat generating plate. 21 are fixed to the outer lid cover 20. Therefore, the work of attaching the coil support base 29 and the heat generating plate 21 to the outer cover 20 is reduced, and the workability of assembling the cover can be improved.

As described above, the coil support base 29 is
6, a gap s is provided between the lower surface of the coil support base 29 and the heating plate 21. The heat of the heat generating plate 21, which generates heat by this gap, is generated by the coil support 2.
9 can be suppressed. That is,
By providing the gap s, a heat insulating effect by the air layer can be obtained, and the deterioration of the coil support base 29 and the lid induction heating coil 22 due to the heat of the heating element 21 can be suppressed.

In particular, the lid induction heating coil 22 generates heat due to the internal resistance and the temperature rises. If the heat of the heating element 21 is further transmitted to the lid induction heating coil 22, the lid induction heating coil 22 may be heated. There is a risk that the temperature of the coil 22 will rise abnormally. Therefore, it is necessary to provide a cooling fan for forcibly cooling the lid induction heating coil 22.
If a cooling fan is provided in 6, the lid itself becomes heavy and the operability of opening and closing the lid is reduced. Therefore, providing the above-described gap s to obtain the heat insulating effect of the air layer is effective in disposing the lid induction heating coil 22 in the lid 16.

In the above embodiment, a high heat insulating effect is obtained by utilizing the heat insulating effect of the air layer due to the gap s. If the support base 29 is made of a material having high heat resistance, the heat transmitted from the heating plate 21 to the lid induction heating coil 22 can be reduced, and a cooling fan for forcibly cooling the lid induction heating coil 22 is not provided. .

In this case, since the distance between the lid induction heating coil 22 and the heating plate 21 is closer, the lid induction heating coil 2
Even if the number of turns of 2 is reduced, the heating plate 21 can be sufficiently induction-heated, so that the temperature rise due to the self-heating of the lid induction heating coil 22 can be suppressed. In short, a gap is provided between the lid induction heating coil 22 and the heating plate 21,
Any configuration may be used as long as heat from the heating plate 21 is prevented from being transmitted to the lid induction heating coil 22.

Since the temperature of the lid induction heating coil 22 rises, when the lid induction heating coil 22 is disposed in the lid 16, the lid must be made of a flame-retardant material. If the coil support base 29 is made of a flame-retardant material, there is no need to use a flame-retardant material for the outer lid cover 20 to which the coil support base 29 is attached, and the manufacturing cost can be reduced.

In addition, the surface of the heating plate 21 on the pot side is covered with a monomolecular film. This monomolecular coating will be described with reference to FIG. That is, when the surface of the heating plate 21 made of stainless steel (SUS445) is sufficiently degreased and then immersed in a fluorine-based chemisorption solution containing a fluoroalkyltrichlorosilane compound in a nitrogen purge, the fluoroalkyltrichlorosilane compound is removed from the heating plate 21. Is dehydrochlorinated with the hydroxyl group on the surface of the heat generating plate 21 to be fixed to the surface of the heat generating plate 21 by a chemical bond, thereby forming a monomolecular film having a fluoroalkyl chain on the surface layer.

The thickness of the monomolecular film is as thin as 3 nm (nanometer). Conventional Fluorocoat thickness is 5
0 to 85 μm (micrometers), the thickness of the monomolecular coating is 1/1 times the thickness of the conventional fluorine coating.
0000. Therefore, the heat transfer of the heat generating plate 21 can be reduced from being hindered by the coating on the surface thereof, the heat transfer property is improved as compared with the conventional fluorine coating, and the upper part of the pot can be efficiently heated. In addition, since the monomolecular film is non-adhesive, it can be easily wiped off even if it adheres to the heating plate 21 from the top of the pot, and the lid can be easily cleaned.

Next, the operation of the above-described rice cooker will be described.
First, when rice cooking is started, the bottom and side portions of the pot 13 are heated by the induction heating coils 17 and 18 and the heater 19. When the rice and water in the kettle 13 are heated and boiling starts,
The upper portion of the pot 13 is filled with steam, and a lid temperature sensor 26 attached to the heating plate 21 detects the steam temperature and detects that boiling has started. The amount of rice and water in the kettle 13 (the amount of rice cooked) in the kettle 13 is determined based on the time required for the lid temperature sensor 26 to start boiling, and the subsequent heating amount of the kettle is determined. In the determination of the amount of cooked rice, the fact that the time until the start of boiling is long when the amount of cooked rice is large, and that the time until the start of boiling is short when the amount of cooked rice is small is utilized.

During the determination of the amount of cooked rice, the lid induction heating coil 22 is not operated to prevent the heating plate 21 from generating heat.
The lid temperature sensor 26 can accurately detect the boiling start point. After the start of boiling is detected by the lid temperature sensor 26, the lid induction heating coil 22 is operated and the heating plate 2 is turned on.
1 is induction-heated, and the upper part of the pot 13 is heated. The lid induction heating coil 22 can strongly heat the heating plate 21 by induction heating, so that the upper part of the pot 13 is sufficiently heated, and the steam on the upper part of the pot 13 is blown off to prevent sticky rice and cook delicious rice. be able to.

When the lid induction heating coil 22 starts operating, the heating plate 21 is induction-heated, but the center side of the ring-shaped lid induction heating coil 22 is more strongly induction-heated than its outer peripheral side. The central steam hole 24 is quickly warmed. Therefore, it is possible to prevent the temperature of the upper part of the pot 13 from being lowered in a state where the temperature of the steam hole 24 is low, and also possible to prevent the dew condensation due to the low temperature of the steam hole 24, and the dew is formed on the rice from the steam hole 24. Can also be prevented from dripping. In particular, in the heat retaining step, since the upper part of the kettle is mainly heated, it is necessary to prevent the temperature of the upper part of the kettle from lowering due to the lowering of the temperature of the steam hole 24. If the structure is hard to lower the temperature,
A good heat retention state can be maintained.

When the boiling is started, steam is generated from the upper part of the pot 13, and the steam is exhausted to the outside of the rice cooker through the steam hole 24 opened in the heat generating plate 21. The water vapor generated in the upper part of the kettle 13 does not leak from the periphery of the lid 16 due to the packing 27.
When rice cooking is started in a state where the rice cooker 7 is deformed and a gap is generated between the flange portion 28 of the pot 13 and the lower end of the packing 27, steam generated from the pot 13 causes the lid 1 to pass through the gap.
6 has a risk of entering. However, since the lid induction heating coil 22 is covered with the flame-retardant material, the quality can be stabilized for a long time without causing insulation deterioration due to the invading water vapor.

(Embodiment 2) Next, a second embodiment of the present invention will be described with reference to FIG. As shown in FIG.
Has a two-layer structure of an aluminum layer 21a and a stainless steel layer 21b. That is, the stainless steel layer 21b is induction-heated by the lid induction heating coil 22. The heat generated by the stainless steel layer 21b is converted to the aluminum layer 21 having high thermal conductivity.
a, and the upper part of the pot can be heated uniformly.

(Embodiment 3) Next, a third embodiment of the present invention will be described with reference to FIG. As shown in FIG.
Has a three-layer structure of a stainless steel layer 21b, an aluminum layer 21a, and a stainless steel layer 21b.
a and the stainless steel layer 21b can be prevented from warping due to a difference in thermal expansion. That is, since the different types of aluminum layers 21a are sandwiched between the same type of stainless layers 21b, distortion due to thermal expansion between the aluminum layers 21a and the stainless layers 21b can be supported by the stainless layers 21b on both sides, and the heating plate 21 warps. To prevent

Therefore, no warping force of the heat generating plate 21 is applied to the outer lid cover 20 to which the heat generating plate 21 is attached.
The deformation of the lid can be prevented. Furthermore, the heating plate 2
Due to the warpage of 1, the gap between the heating plate 21 and the lid induction heating coil 22 changes, so that the heat generation amount of the stainless steel layer 21b can be prevented from changing, and the upper part of the pot can be stably heated.

[0040]

As described above, according to the first aspect of the present invention, there is provided a rice cooker main body for accommodating a pot, and a lid body for opening and closing the upper portion of the rice cooker main body, The lid body has a heat generating portion disposed on the lower surface thereof, has a lid induction heating coil for induction heating the heat generating portion inside thereof, and a magnetic shield is disposed above the lid induction heating coil. Can be sufficiently induction-heated, and the upper part of the pot can be sufficiently heated to cook delicious rice. Also, since it is not necessary to increase the size of the lid induction heating coil in order to obtain a sufficient amount of heating, it is possible to improve the opening / closing operability of the lid without causing the lid to become heavy and hindering the opening / closing operation. it can. In addition, by disposing a magnetic shielding material above the lid induction heating coil, the magnetic field upward from the lid induction heating coil can be shielded by the magnetic shielding material, and the magnetic field can be prevented from leaking out of the lid. , Such as a television.

According to the second aspect of the present invention, since the lid induction heating coil is formed in a ring shape and the steam hole is provided in the ring-shaped opening, the steam hole is sufficiently heated. The temperature of the upper portion of the kettle can be prevented from lowering due to the lowering of the temperature of the steam hole.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view of a rice cooker showing a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part around a lid of the rice cooker.

FIG. 3 is a plan view showing the inside of a lid of the rice cooker.

FIG. 4 is a coil support table, a lid induction heating coil of the rice cooker,
Sectional view of the state where the magnetic shielding material is disassembled respectively

FIG. 5 is an explanatory view of a monomolecular film applied to a heating plate of the rice cooker.

FIG. 6 is a sectional view of a main part around a lid of a rice cooker according to a second embodiment of the present invention.

FIG. 7 is a sectional view of a main part around a lid of a rice cooker according to a third embodiment of the present invention.

FIG. 8 is a sectional view of a rice cooker showing a conventional example.

FIG. 9 is a partially cutaway side view of a rice cooker showing another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 Rice cooker main body 13 Hook 16 Lid 20 Outer lid cover 21 Heating plate (heating part) 22 Lid induction heating coil 34 Magnetic shield

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Toshio Arai 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Atsushi Tanaka 1006 Kadoma, Kazuma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. 1006 Okadoma Kadoma, Fumonma-shi Matsushita Electric Industrial Co., Ltd. FA15

Claims (2)

[Claims] 1. A rice cooker main body accommodating a pot, and a lid body that covers an upper part of the rice cooker body so as to be openable and closable. A rice cooker having a lid induction heating coil for induction heating of a heat generating portion, and a magnetic shielding material disposed above the lid induction heating coil. 2. The rice cooker according to claim 1, wherein the lid induction heating coil is formed in a ring shape, and a steam hole is provided in the ring-shaped opening.