JP3413981B2 - rice cooker - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rice cooker having a lid provided with a heating source for heating an upper portion of a pot. [0002] To cook delicious rice, rice cookers that can heat not only the lower part but also the upper part of the pot have been in the 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 openably and closably covered with 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,
The lid 2 was induction-heated by the lid induction heating coil 3 to heat the upper part of the pot 1. However, when taking out 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 risk of burns when removing the lid 2, and since the lid 2 is hot, it is necessary to pay attention to the place where the removed lid 2 is placed. There was a problem that the operation was troublesome. 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. As shown in the figure, a lid 7 is attached to the top of a rice cooker main body 6 in which a pot 5 is stored so as to be freely opened and closed. 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. 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. The distance of the inner lid 11 became large, so that the induction heating of the inner lid 11 could not be sufficiently performed, and the steam above the kettle 5 could not be sufficiently blown. 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. [0009] In view of the above problems, while a good opening and closing operation of the lid, and an object thereof is to provide a cooker capable of sufficiently heating the top of the kettle. Another object of the present invention is to improve the assemblability of the lid in addition to the above object . [0011] [Means for Solving the Problems] was achieving the above object
Means for solving the problem include a rice cooker main body for accommodating a kettle, and a lid body that covers an upper portion of the rice cooker body so as to be openable and closable. Having a lid induction heating coil disposed therein for induction heating the portion, and a coil support base for supporting the lid induction heating coil being attached to a mounting portion of a heating plate constituting a heating portion. It is. According to the means for solving the above-mentioned problems, a lid is constituted by attaching an outer lid cover and a heat generating plate on the lower surface thereof, and a lid induction heating coil disposed in the lid is provided on a coil support base. And the coil support is attached to the mounting portion between the outer lid cover and the heat generating plate. Therefore, by attaching the outer lid cover and the heat generating plate, the coil support base can be fixed in the lid body, and the assembling workability can be improved. An 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 housing portion 14 for housing a kettle 13 therein. A hinge 15 is provided at the upper rear of the rice cooker main body 12, and a lid 16 that can be opened and closed around the hinge 15 is attached. The lid 16 covers the rice cooker main body 1 so as to cover the upper part of the pot 13.
2 is located at the top. The bottom of the shuttle 13 is induction-heated by the induction heating coils 17 and 18, and the side thereof is
Is heated by a heater 19 wound around the outer periphery of the side surface of the. The cover 16 has an outer frame formed by an outer 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 configuration 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 gasket 27 having a U-shaped cross section is provided on the outer peripheral side of the heat generating plate 21, and the entire lower end of the annular gasket 27 is in close contact with the entire upper surface of the flange 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, the 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. A ferrite support 3 for supporting the ferrite 32 is provided above the coil housing 30.
3 so that the ferrite 32 can be temporarily fixed on the upper part of the coil support base 29. If the ferrite 32 is fixed by injecting the flame-retardant silicon 31 into the coil housing portion 31, the ferrite 32 can be easily fixed on the coil support base 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 upward magnetic field is directed to the lower side of the heat generating plate 21 as much as possible. It is to make it head. The ferrite 32 is mounted on the coil support base 29.
Although the ferrite support portion 33 is temporarily fixed, the lid induction heating coil 22 and the ferrite 32 may be covered together with a flame-retardant material, and both may be fixed before being mounted on the coil support base 29. In this case, the coil support base 29 can be easily assembled. Further, if the coil support base in which the lid induction heating coil and the ferrite are buried with a flame-retardant material is formed, there is no need to mount an induction heating coil or the like on the coil support base, and the assemblability is dramatically improved. Can be enhanced. Although the amount of the magnetic field going upward from the lid induction heating coil 22 can be reduced by the above-described ferrite 32, 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 capable of shielding 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.
9, and is superimposed on the mounting portion of the heat generating plate 21 to be mounted on the outer cover 20.
In this configuration, both the heating plate 9 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 connected to the lid 1
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 is 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, even if the number of turns of the lid induction heating coil 22 is reduced, the heating plate 21 can be sufficiently induction-heated, and thus the lid induction heating can be performed. Temperature rise due to self-heating of the coil 22 can be kept low. In short, the lid induction heating coil 22 and the heating plate 2
1 may be provided as long as a gap is provided between them to prevent the heat from the heat generating plate 21 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. Further, 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 this monomolecular film is extremely thin, 3 nm (nanometer). Conventional fusso coat 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 less hindered by the coating on the surface thereof, and the heat transfer property is improved as compared with the conventional fluorine coating, so that the upper part of the pot can be efficiently heated. In addition, since the monomolecular film has non-adhesiveness, even if it is attached to the heating plate 21 from the upper part of the pot, it can be easily wiped off.
The workability of cleaning the lid is also good. 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 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 suppress the lowering of the temperature of the upper part of the kettle due to the lowering of the temperature of the steam hole 24. If the structure is such that the temperature of the hole 24 does not easily decrease, a favorable heat retaining 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 a 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. Next, another embodiment of the present invention will be described with reference to FIG. As shown in FIG.
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 diffused by the aluminum layer 21a having a high thermal conductivity, so that the upper part of the pot can be heated uniformly. As shown in FIG. 7, the heating plate 21 is made of a stainless steel layer 21b, an aluminum layer 21a and a stainless steel layer 21a.
With the three-layer structure b, it is possible to prevent the occurrence of warpage due to the difference in thermal expansion between the aluminum layer 21a and the stainless steel layer 21b. That is, the same type of stainless steel layer 21b and the different type of aluminum layer 2
1a, the distortion caused by the thermal expansion of the aluminum layer 21a and the stainless steel layer 21b is reduced by the stainless steel layers 2 on both sides.
1b to prevent the heating plate 21 from warping. Therefore, the warpage of the heat generating plate 21 is not applied to the outer lid cover 20 to which the heat generating plate 21 is attached, and the deformation of the lid can be prevented. Further, the gap between the heating plate 21 and the lid induction heating coil 22 is changed due to the warpage of the heating plate 21, thereby preventing a change in the calorific value of the stainless steel layer 21 b, thereby stably heating the upper part of the pot. Can be. As is clear from the above embodiment, the present invention
According to the invention , a lid is configured by attaching an outer lid cover and a heat generating plate on the lower surface thereof, and a lid induction heating coil disposed in the lid is supported by a coil support. Since it is configured to be attached to the mounting portion between the outer lid cover and the heat generating plate, the coil support base can be fixed in the lid by attaching the outer lid cover and the heat generating plate, and the assembling workability can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cut-away side view of a rice cooker showing one embodiment of the present invention. FIG. 2 is a sectional view of a main part around a lid of the rice cooker. FIG. 4 is a plan view showing the inside of the lid of the rice cooker.
FIG. 5 is an explanatory view of a monomolecular coating applied to a heating plate of the rice cooker. FIG. 6 is a sectional view showing a monomolecular coating applied to a heating plate of the rice cooker. FIG. 7 is a cross-sectional view of a main part around a lid of a rice cooker showing still another embodiment of the present invention. FIG. 8 is a cross-sectional view of a rice cooker showing a conventional example. FIG. 9 shows another conventional example. Partial cutaway side view of rice cooker [Explanation of symbols] 12 Rice cooker main body 13 Pot 16 Lid 21 Heat generating plate (heat generating part) 22 Lid induction heating coil

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shoji Shimono 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. In-house (72) Inventor Kiyoshi Horiuchi 1006 Kadoma, Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (72) Inventor Toshiyuki Nakamura 1006 Odaka, Kadoma, Kadoma, Osaka Pref. Person Atsushi Koma 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-6-62956 (JP, A) JP-A-5-111425 (JP, A) JP-A-6-629 178719 (JP, A) JP-A-4-341790 (JP, A) JP-A-5-251167 (JP, A) JP-A-6-319637 (JP, A) JP-A-6-105740 (JP, A) Actual opening 6 −55 515 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) A47J 27/00 103

Claims (1)

(57) [Claims 1] A rice cooker main body accommodating a cooking pot, and a lid body that opens and closes an upper portion of the rice cooker main body, the lid body being disposed on a lower surface thereof. Mounting a heating plate comprising a heating section and a lid induction heating coil disposed therein for induction heating the heating section, and a coil supporting base for supporting the lid induction heating coil constituting a heating section. A rice cooker that is configured to be attached to a part.