JP2008259556A - Electric rice cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve temperature distribution inside an inner pot and improve a rice cooking property in an electric rice cooker using the inner pot made of a nonmetallic material. <P>SOLUTION: This electric rice cooker includes a rice cooker body 1 detachably storing the inner pot 3 made of the nonmetallic material, the inner case 4 constituting the inner circumferential face of the rice cooker body 1 and supporting the stored inner pot 3, and an electromagnetic induction coil C disposed at the bottom part 8 of the inner case 4; is disposed with an induction heating element G generating an eddy current by the electromagnetic induction coil C on the lower surface of the bottom 8 of the inner pot 3; wherein the inner pot 3 consists of the bottom part 8 disposed with the induction heating element G and a tubular part 9 erected from the bottom part 8; and even if this electric rice cooker uses the inner pot 3 made of the nonmetallic material with inferior thermal conductivity, favorably heats contents in the inner pot 3 by the convection from the whole body of the inner pot bottom part 8 heated by the heating of the induction heating element G. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric rice cooker, and more particularly to an electromagnetic induction type electric rice cooker having an inner pot made of a non-metallic material.

  As a well-known electric rice cooker, a rice cooker body configured to detachably accommodate a metal inner pot, and an inner peripheral surface of the rice cooker body and the inner pot Is provided with a protective frame that supports the inner pot and an electromagnetic induction coil that generates electromagnetic induction in the inner pot. In the electric rice cooker having such a configuration, the temperature in the inner pot or in the vicinity of the inner pot is detected. The thing which attached the rice cooking amount detector which detects the amount of rice cooking with the temperature detected with the temperature detector is proposed (refer patent document 1).

  In recent years, attempts have been made to use an inner pot made of a non-metallic material (for example, an earthen pot, a ceramic pot, or a charcoal pot) as an inner pot in order to improve the cooking of rice. In this case, since the inner pot itself does not generate heat due to electromagnetic induction, an induction heating element is disposed at the bottom of the inner pot and in the vicinity of the bottom (for example, a curved portion between the bottom and the side wall), and the induction heating element is The inner pot is heated by generating heat by the magnetic field generated from the induction coil (see Patent Document 2).

Japanese Patent Publication No. 7-36799.

Japanese Patent Application Laid-Open No. 2004-141456.

  By the way, in the case of the electric rice cooker currently disclosed by patent document 1, since the inner pot is comprised with the metal material (especially metal material excellent in thermal conductivity), the bias | distribution generate | occur | produces in the temperature distribution of an inner pot. However, in the case of the electric rice cooker disclosed in Patent Document 2, an inner pot made of a non-metallic material (for example, an earthen pot, a ceramic pot or a charcoal pot) is used. The thermal conductivity is extremely poor. In the case of an electric rice cooker using an inner pot having such characteristics, there arises a problem that the temperature distribution of the inner pot is uneven. In particular, when this type of inner pot is used, improvement of the temperature distribution in the inner pot and improvement of rice cooking performance become problems, and this part is necessary from the place where the support legs that become the hills are required on the outer periphery of the bottom part. There is a problem of uneven thickness and poor formability. In addition, since the heat distribution around the support legs, which are the hills, is very poor, there is a risk of cracking.

  This invention is made | formed in view of said point, In the electric rice cooker using the inner pot which consists of nonmetallic materials, it aims at improving the temperature distribution in an inner pot, and the improvement of rice cooking performance. Yes.

  In this invention, as a 1st means for solving the said subject, while comprising the inner peripheral surface of the rice cooker main body which detachably accommodates the inner pot which consists of nonmetallic materials, and this rice cooker main body, the said inner pot In an electric rice cooker comprising an inner case for supporting the inner case and an electromagnetic induction coil disposed on the bottom lower surface of the inner case, an eddy current is generated by the electromagnetic induction coil on the bottom lower surface of the inner pan. An induction heating element is provided, and the inner pot is constituted by a bottom part on which the induction heating element is provided and a cylindrical part that stands upright from the bottom part.

  Even if it is an electric rice cooker using the inner pot which consists of a nonmetallic material with poor heat conductivity by having constituted as mentioned above, by the convection from the whole inner pot bottom heated by the heat of the induction heating element The contents in the inner pot will be heated well. As a result, it is possible to improve the temperature distribution in the inner pot and improve the rice cooking performance.

  In the invention of the present application, as a second means for solving the above problems, in the electric rice cooker provided with the first means, with respect to the water level scale height A of the maximum rice cooking amount in the inner pot, When the outermost diameter dimension B of the induction heating element is set, it can be a pan shape such that A <B. When configured as such, when the pan shape is such that A ≧ B, Although the cooking unevenness is likely to occur in the up and down direction, by making the pan shape such that A <B, the cooking unevenness is less likely to occur and the rice cooking performance can be further improved.

  In the present invention, as a third means for solving the above problems, in the electric rice cooker provided with the first or second means, the thickness of the bottom of the inner pot is E, and the periphery of the bottom When the thickness of the support leg formed in the part is D and the thickness of the side body part is C, it can also be a pan shape such that E = D <C. Reduces the temperature difference between the support leg and the bottom where the induction heating element is placed, and reduces the heat capacity by reducing the thickness of the lower part of the side that hits the outside of the support leg from the thickness of the upper part of the side, While reducing the heat shock to the inner pot, and making it the same wall thickness as the bottom, distortion during molding can be minimized.

  In the present invention, as a fourth means for solving the above-mentioned problem, in the electric rice cooker provided with the first, second or third means, the bottom part and the cylindrical part in the inner pot The radius of curvature of the continuous R portion can be made as small as possible, and the water level scale of the minimum rice cooking amount can be formed higher than the R portion. In such a configuration, the upper portion from the R portion has a substantially planar shape. Therefore, the loss at the time of forming the water level scale which displays minimum rice cooking amount by transcription | transfer or printing can be reduced as much as possible.

  According to the first means of the present invention, a rice cooker body that detachably accommodates an inner pot made of a non-metallic material, an inner peripheral surface of the rice cooker body, and an inner pot that supports the inner pot when housed. In an electric rice cooker comprising a case and an electromagnetic induction coil disposed on the bottom outer surface of the inner case, an induction heating element that generates eddy currents is disposed on the bottom bottom surface of the inner pot. In addition, an electric rice cooker using an inner pot made of a non-metallic material having poor heat conductivity, wherein the inner pot is constituted by a bottom portion provided with the induction heating element and a cylindrical portion standing upright from the bottom portion. Even in the case, the contents in the inner pot are heated well by convection from the entire bottom of the inner pot heated by the heat generated by the induction heating element, so the temperature distribution in the inner pot is improved. And improved rice cooking performance There is.

  As in the second means of the present invention, in the electric rice cooker provided with the first means, the outermost diameter dimension of the induction heating element with respect to the water level scale height A of the maximum rice cooking amount in the inner pot. When it is set to B, it can also be made into a pan shape such that A <B. When configured as such, when it is set to a pan shape such that A ≧ B, uneven cooking occurs in the vertical direction of the inner pan. Although it is easy to do, by making it the pan shape which becomes A <B, it becomes difficult to generate | occur | produce cooking unevenness and can improve the rice cooking performance further.

  As in the third means of the present invention, in the electric rice cooker provided with the first or second means, the thickness of the bottom of the inner pot is E, and the support legs formed on the peripheral edge of the bottom When the thickness is D and the thickness of the side torso is C, it can also be a pan shape such that E = D <C. By reducing the temperature difference from the bottom where the is placed, and by making the thickness of the lower part of the side that hits the outside of the support leg thinner than the thickness of the upper part of the side, the heat capacity is reduced and the heat shock to the inner pan is reduced. At the same time, by making the wall thickness the same as the bottom surface, distortion during molding can be minimized.

  As in the fourth means of the present invention, in the electric rice cooker provided with the first, second or third means, the radius of curvature of the R part where the bottom part and the cylindrical part in the inner pot are continuous. Can be formed as high as possible, and the water level scale of the minimum amount of rice can be formed higher than the R portion. When configured in this way, the minimum rice cooking amount is displayed from the point where the portion above the R portion is substantially flat. Loss when forming the water level scale by transfer or printing can be reduced as much as possible.

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

  In this electric rice cooker, as shown in FIGS. 1 and 2, for example, a pot made of a non-metallic material (for example, an earthen pot, a ceramic pot, a charcoal pot, etc.) is employed as the inner pot 3 for storing rice and water. The rice cooker body 1 is configured so that the inner pot 3 can be set arbitrarily, and the lid 2 is provided on the top of the rice cooker body 1 so as to be openable and closable.

  The rice cooker main body 1 constitutes the inner peripheral surface of the rice cooker main body 1 and has an inner case 4 made of a synthetic resin having a bottomed cylindrical shape formed so that the inner pot 3 can be set arbitrarily. An outer case 5 made of a cylindrical sheet metal that constitutes the outer surface of the rice cooker body 1, and an annular synthetic resin shoulder member 6 for connecting the upper end of the outer case 1 and the upper end of the inner case 4 , And a bottom member 7 made of a synthetic resin that closes the lower end opening of the outer case 5.

  The inner pot 3 is constituted by the bottom portion 8 and a cylindrical portion 9 that stands upright from the bottom portion 8. If it does in this way, it becomes possible to make the outermost diameter B (refer FIG. 3) of the induction heating element G provided in the lower surface of the bottom part 8, and the inner diameter dimension of the inner pot 3 substantially the same, and the induction heating element G The heat from the heat spreads to every corner of the rice in the inner pot 3.

  An annular support leg 10 is integrally projected on the outer peripheral part of the bottom part 8, and the support leg 10 is disposed on the outer periphery of the bottom part of the inner case 4 at equal intervals in the circumferential direction. The inner pot 3 is housed and supported in the inner case 4 by coming into contact with three support bases 11, 11, 11 made of (for example, silicon rubber).

  On the other hand, the inner case 4 includes a bottom portion 4a, a cylindrical portion 4b that stands upright from the outer periphery of the bottom portion 4a, and a flange portion 4c that is integrally formed at the upper end of the cylindrical portion 4b. A warming heater 12 is disposed on the outer peripheral side of the heater. Reference numeral 13 denotes a heat insulating material that blocks heat radiation from the heat retaining heater 12 to the outside.

  On the lower surface of the bottom portion 8 of the inner pot 3 (that is, on the inner peripheral side of the support leg 10), a metal induction heating element G such as a silver paste capable of self-heating by an eddy current induced therein is used. Is pasted. By the way, a metal spraying heat generating layer acting as an induction heating element may be formed on the inner surface or inner and outer surfaces of the inner pot 3. In some cases, a metal spray heat transfer layer continuous with the metal spray heat generation layer may be formed. In addition, aluminum or an aluminum alloy can also be used as the metal spray heat generating layer and the metal spray heat transfer layer. Furthermore, as the induction heating element G, a metal plate other than a silver paste or a metal sprayed layer can be adopted, and the induction heating element G may be embedded in the inner pot 3.

  A coil cover 14 is provided below the bottom wall (bottom) 4a of the inner case 4, a ferrite core 15 is disposed at the lower portion thereof, and the lower surface of the bottom portion 8 of the inner pot 3 is disposed at the upper portion thereof. Corresponding to the position of the side induction heating element G, an electromagnetic induction coil (hereinafter referred to as a work coil) C in which litz wires are concentrically wound is provided, whereby the induction heating of the inner pot 3 when energized. An eddy current is induced in the body G to indirectly heat the inner pot 3.

  At the center of the dish-shaped bottom 4a of the inner case 4, there is formed a sensor part fitting port of the center sensor CS acting as a temperature detecting means, and a donut-shaped upper surface on the outer peripheral side of the sensor part fitting port. A heat shield plate 16 is provided.

  And as shown in FIG. 3, when it is set as the outermost-diameter dimension B of the said induction heating body G with respect to the water level scale height A of the largest rice cooking amount in the said inner pot 3, the pan which will be set to A <B. It is made into a shape. If it does in this way, when it is set as the pan shape which becomes A> = B, it will be easy to generate cooking unevenness in the up-and-down direction of the inner pot, but cooking unevenness will occur by having made the pan shape so that A <B. It becomes difficult to cook, and the rice cooking performance can be further improved. In addition, when the height of the inner pot 3 is A ', and the radial dimension of the bottom 3a of the inner pot 3 is B', there may be a pot shape such that B '/ 2 <A' <B '. In that case, the balance of the whole product is improved, and the size becomes compact.

  By the way, when the thickness of the bottom 8 in the inner pot 3 is E, the thickness of the support leg 10 formed on the peripheral edge of the bottom 8 is D, and the thickness of the upper side is C, E = D <C In some cases, the pan shape is as follows. In this way, the temperature difference between the support leg 10 that is not easily heated and the bottom 8 on which the induction heating element G is disposed is reduced, and the thickness D of the lower portion of the side surface (ie, the support leg 10) that contacts the outside of the support leg 10. Is made thinner than the wall thickness C at the top of the side, heat capacity is reduced, heat shock to the inner pot 3 is reduced, and the same thickness as the bottom is used to minimize distortion during molding. Can do. In addition, since the thickness D of the lower side portion (that is, the support leg 10) corresponding to the outer side of the support leg 10 in the inner pot 3 is made thinner than the thickness C of the upper side surface, a comparison is made between this portion and the inner case 4. A large air layer K (see FIGS. 1 and 2) is formed, and a heat insulating effect can be secured.

  Furthermore, in this Embodiment, while making the curvature radius of the R part 17 in which the said bottom part 8 and the said cylindrical part 9 in the said inner pot 3 continue as small as possible, the water level scale 18 (refer FIG. 3) of minimum rice cooking amount. ) Is formed above the R portion 17. If it does in this way, from the place where the upper part from R part 17 becomes a near perpendicular plane shape, the loss at the time of forming the water level scale 18 which displays the minimum amount of rice cooking by transfer or printing can be reduced as much as possible. .

  On the other hand, the cover body 2 is composed of a synthetic resin outer cover 20 having an outer peripheral surface and having a packing 19 at the center, and a synthetic resin made by fitting and integrating inside the outer cover 20. The inner frame 21, the packing 22 a and the metal heat sink 23 in the inner opening of the inner frame 21, the lid heater 24 provided on the upper surface of the heat sink 23, and the heat sink 23 are provided below the heat sink 23. And an inner lid 25 made of metal, and is pivotally supported via a hinge unit 26 so as to be openable and closable with respect to one side of the upper portion of the rice cooker body 1 (that is, the shoulder member 6). . The lid 2 is held in a closed state via a lock mechanism 27 on the opposite side of the hinge unit 26. Reference numeral 28 denotes a lock release lever for releasing the lock state of the lock mechanism 26.

  Further, packings 22a and 22b are respectively provided below the outer peripheral edge of the heat radiating plate 23 and below the outer peripheral edge of the inner lid 25, and the inner lid 25 is connected to the flange of the inner pot 3 via the packing 22b. It is made to contact the upper surface part of the part 3a. The inner pot flange portion 3a has substantially the same thickness as that of the cylindrical portion 9, and a flat portion 36 is formed on the upper surface thereof to which the packing 22b is pressed when the lid body 2 is closed. Reference numeral 29 is a pressure adjusting cover, 30 is a lower side cap thereof, and 31 is a pressure adjusting ball.

  By the way, in the case of the electric rice cooker of the said structure, since the flange part 3a of the inner pot 3 is easy to cool, the annular shoulder heater 32 is arrange | positioned between the flange part 4c of the inner case 4, and the shoulder member 6, and this shoulder The inner pot flange portion 3 a is heated by the heater 32. In this case, in order to effectively receive the upward heat from the shoulder heater 32, it is desirable to extend the inner pot flange portion 3 a to a position covering the upper side of the shoulder heater 32. In addition, as shown in FIG. 4, a build-up portion 33 may be formed at a portion facing the shoulder heater 32 in the upper side of the inner pot 3 so as to easily receive heat from the shoulder heater 32. If it does in this way, the heat storage effect in the build-up part 33 will improve, and not only the heat retention state of the inner pot 3 will become favorable, but the heat between the inner pot 3 and the inner case 4 will be the inner pot flange part 3a. It is also possible to prevent escape from the gap between the shoulder member 6 and the shoulder member 6, and the heat retaining state of the inner pot 3 becomes even better.

  By the way, the recesses 34, 34, 34, 34 that are recessed from the other parts are formed in the shoulder member 6 on the hinge unit 26 side, the lock mechanism 27 side, and the part for taking out the inner pot 3 orthogonal thereto. The recesses 34, 34, 34, 34 are such that the inner pot flange portion 3 a is easily affected by outside air even when the lid 2 is closed. Therefore, in the present embodiment, the shoulder heater 32 is brought into contact with the lower surface of each concave portion 34 (see FIG. 5 (a)), while the portion other than the portion where the concave portions 34, 34, 34, 34 are formed. A gap S is formed between the shoulder heater 32 and the shoulder member 6 (see FIG. 5B). If it does in this way, it will become easy to transmit the heat from the shoulder heater 32 to the site | part in which the recessed part 34 is formed (site where the inner pot flange part 3a is easy to be influenced by external air), and dew to the inner pot flange part 3a will be carried out. Can be suppressed. As an alternative, as shown in FIG. 6 (a), in a portion where the inner pot flange portion 3a is easily affected by outside air, the thickness d of the shoulder member 6 near the inner pot flange portion 3a is reduced. In the case, or as shown in FIG. 6 (b), in a portion where the inner pot flange portion 3a is easily affected by the outside air, a material having good thermal conductivity (for example, aluminum) is provided between the shoulder member 6 and the shoulder heater 32. Etc.).

  In the drawing, reference numeral 36 is an operation panel, 37 is an operation board, 38 is a power supply board, 39 is a cooling fan, and 40 is a heat sink.

  The invention of the present application is not limited to the above-described embodiment, and it is needless to say that the design can be appropriately changed without departing from the gist of the invention.

It is a longitudinal cross-sectional view of the electric rice cooker concerning embodiment of this invention. It is II-II sectional drawing of FIG. It is a half cross-sectional view of the inner pot in the electric rice cooker concerning embodiment of this invention. It is a principal part expanded sectional view in the modification of the electric rice cooker concerning embodiment of this invention. The main part in the electric rice cooker concerning embodiment of this invention is expanded, (I) is an important part expanded sectional view in the site | part in which an inner pot flange part is easy to be influenced by external air, (B) is other It is a principal part expanded sectional view in a site | part. It is what expanded the principal part in the modification of the electric rice cooker concerning embodiment of this invention, (I) is principal part expanded sectional drawing in the site | part in which an inner pan flange part is easy to be influenced by external air, (b) These are the principal part expanded sectional views in another site | part.

Explanation of symbols

1 is a rice cooker body 2 is a lid 3 is an inner pot 3a is a flange part 4 is an inner case 6 is a shoulder member 8 is a bottom part 9 is a cylindrical part 17 is an R part C is an electromagnetic induction coil (work coil)
G is induction heating element

Claims (4)

A rice cooker body that detachably accommodates an inner pot made of a non-metallic material, an inner case that constitutes an inner peripheral surface of the rice cooker body and supports the inner pot when accommodated, and a bottom portion of the inner case An electric rice cooker provided with an electromagnetic induction coil that is provided with an induction heating element that generates eddy current by the electromagnetic induction coil on the bottom lower surface of the inner pot, and the inner pot, An electric rice cooker comprising a bottom portion provided with an induction heating element and a cylindrical portion standing upright from the bottom portion. 2. The pan shape is such that A <B when the outermost diameter dimension B of the induction heating element is set to the water level scale height A of the maximum rice cooking amount in the inner pot. The electric rice cooker described. A pan in which E = D <C, where E is the thickness of the bottom of the inner pan, D is the thickness of the support legs formed on the peripheral edge of the bottom, and C is the thickness of the side barrel. It was set as the shape, The electric rice cooker as described in any one of Claim 1 and 2 characterized by the above-mentioned. 2. The radius of curvature of the R portion where the bottom portion and the cylindrical portion of the inner pot are continuous is made as small as possible, and the water level scale of the minimum rice cooking amount is formed higher than the R portion. The electric rice cooker as described in any one of 2 and 3.

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