JP2008228983A - Electric rice cooker - Google Patents

Abstract

A heat generating drive work coil of an induction heating element provided at the bottom of an inner pot is insulated and protected, and the heat insulating protective member is also effectively used for heating the bottom of the inner pot.
SOLUTION: An inner pot 3 made of a non-metallic material having an induction heating element 36 provided on an inner pot bottom 31, a rice cooker body 1 having a bottomed cylindrical inner case 12, and a bottom wall portion of the inner case 12. In an electric rice cooker provided with electromagnetic induction heating means (work coil) 41 that is below 13 and electromagnetically heats the inner pot 3 via an induction heating element 36, the induction heating element on the bottom wall portion 13 of the inner case By installing a heat insulating plate 5 made of a highly heat storage material that is magnetically permeable and has high heat storage properties at a portion where the 36 is opposed, the heat radiation plate 5 blocks the downward radiant heat from the induction heating element 36. Thus, the work coil 1 and the like are prevented from abnormally rising in temperature, and the inner pot bottom 31 can be auxiliary-heated by the heat storage power, reflected heat, etc. of the heat insulating plate 5 in the unevenness process after the completion of cooking. .
[Selection] Figure 2

Description

  The present invention relates to an electromagnetic induction heating type electric rice cooker that employs an inner pot made of a non-metallic material such as ceramic.

  Recent electric rice cookers have high output, high heating efficiency, and high output control responsiveness, so that the inner pot (rice cooker) can be heated by electromagnetic induction for reasons such as being able to cook delicious rice quickly. There are a lot of things to do.

  By the way, in this kind of electric rice cooker of electromagnetic induction heating type, in order to cook rice more deliciously, it is effective to cook with a strong heating power (thermal power) at a stretch by sufficiently heating the inner pot itself. In addition, it is important to carry out effective “spotting” with sufficient heat retention after cooking. Therefore, in order to meet such demands, non-metallic materials such as ceramics that have good heat storage properties (and are difficult to cool immediately once heated) in the above-described electric induction heating type electric rice cookers recently. The one using the inner pot (so-called earthenware pot) made of made is adopted.

  An electromagnetic induction heating type electric rice cooker using such a clay pot is generally a non-metallic material inner pot (earthen pot) provided with an induction heating element made of a magnetic material on the bottom lower surface, and a rice cooker having an inner case. It has a main body and electromagnetic induction heating means (work coil) installed below the bottom wall of the inner case. And by energizing the work coil in a state where the inner pot (earthen pot) is set in the inner case of the rice cooker body, an eddy current is caused to flow through the induction heating element to generate heat. The inner pot (earthen pot) is heated indirectly to cook rice (see, for example, Patent Document 1).

  Moreover, in this kind of electric rice cooker, when cooking is completed in the rice cooking process, the process proceeds to the uneven process. In this uneven process, the electromagnetic induction heating means (work coil) for rice cooking is set to 0FF. Or, it can be reduced to a small output, and the rice in the inner pot can be made sufficiently uneven due to the residual heat stored in the inner pot itself. Then, when the unevenness process ends, the process finally proceeds to the heat retention process.

  By the way, in such an electric rice cooker, the induction heating element at the bottom of the inner pot is heated to a high temperature of about 220 ° C. to 230 ° C. at the time of the induction heating, but the heat from the induction heating element is While being used for cooking rice, it is also radiated to the bottom wall side of the inner case. And since the heat radiated from the induction heating element to the inner case bottom wall side may heat the inner case bottom wall part and raise the temperature of the work coil installed therebelow, the inner case Measures to prevent temperature rise (insulation measures, etc.) on the bottom wall and work coil are required.

  Therefore, as a countermeasure for preventing the temperature rise of the inner case bottom wall part and the work coil that has already been proposed, for example, by installing a heat insulating plate on the part facing the induction heating element of the inner pot bottom part on the inner case bottom wall part, Prevents radiant heat from the induction heating element from being radiated to the bottom wall of the inner case and the work coil installation part, and cools the work coil part by supplying cooling air to the work coil part with a fan as necessary. (For example, see Patent Document 2 as a non-known prior art document).

Japanese Patent Laying-Open No. 2005-413 (FIGS. 3 and 4) Japanese Patent Application No. 2006-81180 (FIGS. 1, 2, and 6-9)

  However, the above-described heat insulating plate is only used as a heat insulating material that simply shields the radiant heat from the induction heating element of the inner pot. For example, the heat storage function, the emission of infrared rays, the reflection function, etc. are particularly considered. It has not been.

  Therefore, in the present invention, in view of the circumstances as described above, a heat insulating plate is installed on a portion of the inner pot bottom wall portion where the induction heating element faces the inner case bottom, and the radiant heat from the induction heating element is generated by the inner case. While preventing radiation to the bottom wall and work coil side, by adopting a heat storage function, heat reflection function, infrared emission function, etc. as the heat insulating plate, it effectively acts as an auxiliary heating source. It is intended to provide an electric rice cooker that can improve the heat-retaining function of the inner pot in the water absorption, the heating power increase in the cooking process, and the unevenness process (or heat retention process) after the completion of cooking.

  In order to achieve the same object, the present invention is configured with the following problem solving means.

(1) Invention of Claim 1 The invention of Claim 1 of the present application has an inner pot made of a nonmetallic material having an induction heating element at the bottom, and a bottomed cylindrical inner case, and the inner case has an inner case. An electric rice cooker comprising a rice cooker body that can accommodate a pan so that the pan can be removed, and electromagnetic induction heating means that electromagnetically heats the inner pan via an induction heating element below the bottom wall of the inner case In the present invention, a heat insulating plate made of a highly heat storage material that is magnetically permeable and has a high heat storage property is installed on a portion of the bottom wall portion of the inner case facing the induction heating element.

  The electromagnetic induction heating means used in the present invention is generally called a work coil (or heating coil). In the following description, the electromagnetic induction heating means is called a work coil. is there.

  As the heat insulating plate, one made of ceramic or natural stone can be adopted. As materials for these (ceramic and natural stone), materials having magnetic permeability and good heat insulation and heat storage properties are selected. In addition, when the heat insulating property and the heat storage property are good as described above, it is difficult to raise the temperature, but once the temperature is raised, it is difficult to cool for a long time and the heat retaining property is good.

  And this heat insulation plate is installed so as to face the induction heating element at the bottom of the inner pan as described above, but when the electromagnetic induction heating means (work coil) is energized, the electromagnetic induction heating means (work coil). The alternating magnetic field from can pass through the heat insulating plate and heat the induction heating element at the bottom of the inner pot without any problem.

  By the way, in the electric rice cooker of the present invention, when the induction heating element at the bottom of the inner pot generates heat, the inner pot is heated and rice cooking is performed. While the pan (pan bottom) is heated, it is also radiated downward (inner case bottom wall).

  However, in this invention, since the heat insulating plate is installed as described above so as to face the induction heating element at the bottom of the inner pot, the heat from the induction heating element at the time of rice cooking is reduced to the inner case bottom wall (workpiece below this It is possible to prevent transmission to the side where the coil is installed. Therefore, the heat insulation plate can prevent the work coil from being heated by radiant heat from the induction heating element.

  In addition, during cooking, the heat insulating plate on the bottom wall of the inner case is heated by radiant heat from the induction heating element. However, the heat insulating plate of the present invention is difficult to cool once heated (as described above). Therefore, even if the work coil is turned off (or low output) at the completion of cooking, for example, the high temperature state is maintained for a certain period of time. Then, after completion of cooking, the process proceeds to the unevenness process (for example, a process in which the work coil is OFF or low output, the heat retaining heater and the lid heater are ON, and the cooked cooked rice is maintained at about 110 ° C. for several minutes). At that time, the heat-insulating plate, which is sufficiently heated and stored, dissipates heat, and the radiant heat heats the bottom of the inner pot in an auxiliary manner.

  In addition, if a ceramic or natural stone or carbon-containing material is used as the heat insulating plate, the heat insulating plate will radiate far infrared rays effectively when it dissipates heat, and the heating effect with high thermal efficiency due to the far infrared rays. Can also be expected.

(2) Invention of Claim 2 Invention of Claim 2 of this application WHEREIN: In the electric rice cooker of the said Claim 1, the heat | fever reflective surface which reflects the heat from an induction heating body is provided in the lower surface side of the said heat insulation plate. It is characterized by.

  The heat reflecting surface is preferably a silver reflecting surface having a high heat reflectivity, for example.

  When the heat reflecting surface is provided on the heat insulating plate in this way, radiant heat from the induction heating element at the bottom of the inner pot to the heat insulating plate can be stored in the inner pot side heat storage material layer portion, while the inner pot on the electromagnetic induction heating means side heat reflecting surface. It can be efficiently reflected to the bottom side.

(3) Invention of Claim 3 Invention of Claim 3 of this application WHEREIN: In the electric rice cooker of the said Claim 1 or 2, an electroconductive material layer is provided in the said heat insulation plate, and an electroconductive material is provided by the alternating magnetic field from a work coil. The heat-insulating plate itself generates heat through the layers.

  As the conductive material layer provided on the heat insulating plate, for example, a silver-colored material having a high heat reflectance can be adopted. The conductive material layer of the heat insulating plate is preferably provided in a very thin state so that the alternating magnetic field from the work coil can be sufficiently transmitted to the induction heating element at the bottom of the inner pot.

  As described above, when the conductive material layer is provided on the heat insulating plate, the conductive material layer of the heat insulating plate can also generate heat by the alternating magnetic field from the work coil, and thereby, when cooking rice (at least when the work coil is ON). The heat insulating plate itself can be supplementarily heated by the heat generated from the conductive material layer.

  In addition, if the portion is silver, the heat reflectivity is increased and the heating efficiency is improved.

(4) Invention of Claim 4 Invention of Claim 4 of this application WHEREIN: In the electric rice cooker of any one of the said Claim 1 to 3, the carbon material which discharge | releases a far infrared ray is made to adhere to the said heat insulation plate. It is characterized by.

  As described above, when the carbon material is attached to the heat insulating plate, when the heat insulating plate is heated, the heat is efficiently absorbed and stored, and a large amount of far-infrared rays are emitted from the carbon material during heat dissipation. Since the inner pot is heated with infrared rays efficiently, the heating effect of the inner pot is further improved.

(5) Invention of claim 5 The invention of claim 5 of the present application is the electric rice cooker according to any one of claims 1 to 4, wherein the second induction heating element is provided on the curved portion of the inner pot bottom outer periphery, A second electromagnetic induction heating means (work coil) is provided below the curved portion on the outer periphery of the bottom wall portion of the inner case to perform electromagnetic induction heating corresponding to the second induction heating element. A heat-insulating plate made of a highly heat-storable material that is magnetically permeable is also provided at a portion of the curved portion facing the second induction heating element.

  In the electric rice cooker of the present invention, the inner pot can be heated at each position (a wide area portion) of the bottom wall portion side first induction heating element portion and the bottom wall portion outer periphery side second induction heating element portion.

  And in that case, since the heat insulating plate made of a high heat storage material is also installed in the part corresponding to the second induction heating element as in the case of the first induction heating element, the heat insulation by the heat insulation plate, The area of each part of heat storage and heat dissipation can be increased.

  In addition, the heat insulating plate at the portion facing the second induction heating element may be integrally formed with the heat insulating plate at the portion facing the first induction heating element, or may be formed separately. .

  Hereinafter, several embodiments of the present invention will be described with reference to FIGS. First, FIG. 1 shows a basic overall configuration of an electric rice cooker body common to each embodiment, and FIG. 2 shows heat insulation in the electric rice cooker of the first embodiment based on the configuration of FIG. The structure of the plate is shown, FIG. 3 shows a second embodiment in which the structure of the heat insulating plate in the electric rice cooker of the first embodiment is modified, and FIGS. 4 to 5 also show the first embodiment. 3rd Embodiment which deform | transformed the structure of the heat insulation plate in the electric rice cooker of embodiment of this is shown, and FIGS. 6-7 shows the 1st which changed the structure of the heat insulation plate in the electric rice cooker of 3rd Embodiment. Four embodiments are each shown.

<Overall configuration of an electric induction cooker of electromagnetic induction heating type common to each embodiment>
First, an overall configuration of an electromagnetic induction heating type electric rice cooker common to the above embodiments will be described with reference to FIG. This electric rice cooker includes a rice cooker body 1 in which a bottomed cylindrical inner case 12 is accommodated in an outer case 11, a lid unit 2 that opens and closes an upper portion of the rice cooker body 1, and an inner case 12 of the rice cooker body 1. An inner pot 3 that is housed in a removable manner; electromagnetic induction heating means 41 and 42 that are installed below the bottom wall 13 of the inner case 12 and electromagnetically heat the inner pot 3; and an inner case bottom The heat insulating plate 5 installed on the upper surface of the wall 13 is used as a basic structure.

  In each embodiment of the present application, two work coils (the first work coil 41 and the second work coil 42) are used as the electromagnetic induction heating means 41 and 42. In the following description, electromagnetic induction heating is used. The means 41 and 42 will be simply referred to as first and second work coils 41 and 42.

  The rice cooker body 1 has a double structure of an outer case 11 and an inner case 12, and a space of a predetermined interval for installing various members is formed between the outer case 11 and the inner case 12. .

  The lid unit 2 has a lid body 21 that opens and closes the opening of the rice cooker body 1, and an inner lid 22 that is attached to the lower surface side of the lid body 21 and opens and closes the opening of the inner pot 3. . The lid unit 2 has a lid body 21 hinged to the rear upper part of the rice cooker body 1 so that the entire lid unit (the lid body 21 and the inner lid 22) can be simultaneously opened and closed in an arc. Yes.

  The inner pot 3 is made of a ceramic having high heat resistance such as cordierite (so-called earthen pot), and has a flat bottom portion 31, a curved portion 32 on the outer peripheral side of the bottom portion 31, and a cylindrical side wall. It is formed in a bottomed cylindrical shape integrally formed with the portion 33. On the lower surface of the outer peripheral portion of the bottom portion 31, a small and high annular hill portion 34 is formed so as to protrude downward. In this embodiment, the inner portion surrounded by the hill portion 34 in the inner pot 3 is referred to as a bottom portion 31, and the curved surface portion (the round surface portion) outside the hill portion 34 is referred to as a curved portion 32. Moreover, in the following description, the said bottom part 31 and the said curved part 32 are named generically, and the inner pot lower part (or inner pot lower surface) is called.

  The inner case 12 is formed in a bottomed cylindrical shape by integrally assembling a heat-resistant synthetic resin bottom wall portion 13, a metal side wall portion 14, and a synthetic resin shoulder member 15.

  The bottom wall portion 13 of the inner case 12 is formed in a deep dish shape that can surround the outer sides of the bottom portion 31 and the curved portion 32 of the inner pot 3. That is, the inner case bottom wall portion 13 has an inner pot bottom facing portion 13 a that faces the bottom 31 of the inner pot 3 and a curved portion facing portion 13 b that faces the curved portion 32 of the inner pot.

  And when the inner pot 3 is accommodated in the inner case 12 and the inner pot hill part 34 is seated on the inner case bottom wall part 13, it is between the lower surface of the inner pot 3 and the upper surface of the inner case bottom wall part 13. A gap with a small interval is appropriately formed. In addition, the inner pan hill part 34 is a receiving member (for example, three places) provided in a spot shape on the upper surface of the inner case bottom wall part 13 (upper surface of the heat insulating plate 5 in the case of FIG. 3 described later). (For example, rubber) 13c.

  The inner pot 3 used in the present application is heated by electromagnetic induction. In this embodiment, the first induction heating element 36 is pasted on the lower surface of the inner pot bottom 31 and the outer surface of the curved portion 32 is the first. Two induction heating elements 37 are attached. The first and second induction heating elements 36 and 37 generate heat by inducing eddy currents by the alternating magnetic fields from the first work coil 41 and the second work coil 42, respectively, and the inner pot is heated by the heat. 3 is heated.

  For the first induction heating element 36 and the second induction heating element 37, for example, a metal material such as silver paste is used. The first induction heating element 36 is provided in a considerably large area inside the hill part 34 on the lower surface of the inner pot. In addition, since the temperature detection sensor 10 of an inner pot contacts the center part of the inner pot bottom 31 lower surface, the part which the temperature detection sensor 10 of the inner pot bottom 31 lower surface is in a state without a heat generating body as an example. . The second induction heating element 37 is provided in an annular shape having a predetermined width on the outer surface of the curved portion 32 outside the hill portion 34 on the lower surface of the inner pot.

  On the lower surface side of the inner case bottom wall portion 13, first and second work coils 41, 42 for induction heating the induction heating elements 36, 37 of the inner pot 3 are installed. The first work coil 41 and the second work coil 42 are respectively installed between the lower surface of the inner case bottom wall 13 and the coil cover 43 located below the inner case bottom wall 13. In this embodiment, each of the work coils 41 and 42 is attached to the upper surface of the coil cover 43 and is separated from the lower surface of the inner case bottom wall portion 13 by a small gap.

  In this embodiment, the number of turns of the second work coil 42 is less than the number of turns of the first work coil 41 so that the heat generation temperature of the second induction heating element 37 by the second work coil 42 is the first. The heat generation temperature of the first induction heating element 36 by one work coil 41 is made smaller than that.

  In addition, in the electric rice cooker of FIG. 1, the code | symbol 16 is the heat retention heater attached to the outer surface of the inner case side wall part 14, and the code | symbol 26 is the lid | cover heater provided in the lid body 21. FIG. The heat retaining heater 16 and the lid heater 26 can heat the inner pot 3 together with the induction heating elements 36 and 37 that generate heat from the work coils 41 and 42 even during rice cooking.

  By the way, in each embodiment of this application, the so-called earthen pot made from a ceramic is employ | adopted as the inner pot 3. As described above, in the case where the earthenware pot is used for the inner pot 3, it is difficult to cool once the temperature is raised, but the heat conductivity at the time of heating is poor. Therefore, in the inner pot 3 used in this type of electromagnetic induction heating type electric rice cooker, the thickness of the heated portion (the portion where the first and second induction heating elements 36 and 37 are present) at the lower portion of the inner pot 3. The thickness is made thinner than that of the side wall portion 33 so that the heat from the induction heating elements 36 and 37 is quickly conducted to the inner surface of the inner pot 3. In the illustrated embodiment, each thickness of the inner pot bottom 31 and the curved portion 32 is, for example, about 4 mm. On the other hand, the thickness of the side wall 33 of the inner pot 3 is relatively thick (for example, about 7 mm), as long as it is gradually heated during cooking. If the thickness of the inner pot side wall 33 is increased in this way, the temperature rise will be slow, but the amount of heat stored at the completion of cooking will increase and it will be difficult to cool, so the uneven efficiency in the uneven process (or in the heat retaining process) (Heat insulation efficiency) is improved.

  By the way, when the first and second work coils 41 and 42 are energized in the state of the inner pot set at the time of cooking rice, the first induction heating element 36 and the second are generated by the alternating magnetic field from the work coils 41 and 42. Each induction heating element 37 generates heat, and in particular, the heat generation temperature of the first induction heating element 36 reaches a maximum of 220 ° C. to 230 ° C. The heat from the induction heating elements 36 and 37 is conducted to the lower part of the inner pot (the inner pot bottom 31 and the curved part 32) to heat the inner pot 3, and is also radiated to the inner case bottom wall 13 side. The As it is, the inner case bottom wall portion 13 is heated to an abnormally high temperature by radiant heat from the induction heating elements 36 and 37, and the work coils 41, which are installed on the lower side of the inner case bottom wall portion 13, There is a danger that the temperature of 42 is abnormally increased. In particular, when cooking rice, the heat generation temperature of the first induction heating element 36 in the inner pot bottom 31 is as high as 220 ° C. to 230 ° C., so the first work coil on the lower side of the inner case bottom wall 13 For 41, means for preventing abnormal temperature rise is required.

  Therefore, in the electric rice cooker of each embodiment of the present application, the heat-insulating plate 5 having magnetic permeability is installed on the inner case bottom wall portion 13 on the portion facing the first induction heating element 36 of the inner pot bottom portion 31, The radiant heat from the first induction heating element 36 is prevented from being conducted to the inner case bottom wall 13 and the first work coil 41 side. The heat insulating plate 5 is made of a highly heat storage material that is magnetically permeable and has as much heat storage as possible, and has a heat reflectance function, a far-infrared emission function, and a self-heating function. In addition to the heat insulating function, the heat insulating plate 5 is provided with an auxiliary heating function in each process such as water absorption, cooking, and unevenness after completion of cooking (to ensure energy saving).

  Hereinafter, some embodiments of the configuration of the heat insulating plate 5 will be described.

<First Embodiment>
First, FIG. 1 and FIG. 2 have shown the structure of the heat insulation plate which concerns on the electric rice cooker of 1st Embodiment of this invention.

  In the first embodiment, for example, as shown in FIGS. 1 and 2, the heat insulating plate 5 has substantially the same area as the first induction heating element 36 in the inner pot bottom 31 and a thickness of, for example, about 3 to 4 mm. The shape is used.

  In addition, the center part of the heat insulation plate 5 has a hole through which the temperature detection sensor 10 is inserted. The heat insulating plate 5 is adhered to a portion of the upper surface of the inner case bottom wall portion 13 where the first induction heating element 36 faces.

  Moreover, this heat insulation plate 5 is shape | molded with the high heat storage material like the ceramic and natural stone (granite) of the same material as the inner pot 3, for example. These materials (ceramics and natural stones) are magnetically permeable and have good heat insulation and heat storage properties. As described above, when the heat insulating property and the heat storage property are good, it is difficult to raise the temperature, but the heat storage property is high, and once the temperature is raised, it is difficult to cool. Therefore, the heat insulating plate 5 made of such a material has a high heat storage capacity to absorb and hold the radiant heat in addition to the function of insulating the radiant heat from the first induction heating element 36.

  In the first embodiment, a heat insulating plate is not interposed between the second induction heating element 37 and the second work coil 42 in the curved portion 32 of the inner pot 3, but the second induction As described above, the heating element 37 has a low heat generation temperature because the number of turns of the second work coil 42 is small, and the vicinity of the second induction heating element 37 and the vicinity of the second work coil 42 are Since it is near the outer periphery of the inner pot 3 and is open to the outside, heat is not easily trapped (heat is easily dissipated). Therefore, a heat insulating plate is particularly provided at a position facing the second induction heating element 37. Even if the second work coil 42 is not provided, the temperature of the second work coil 42 does not rise abnormally. The inner case 12 itself is also formed of a synthetic resin having high heat resistance.

  In the electric rice cooker according to the first embodiment shown in FIGS. 1 and 2, the heat insulating plate 5 functions as follows.

  First, when each work coil 41, 42 is energized during rice cooking, the alternating induction magnetic field from each work coil 41, 42 causes the first induction heating element 36 and the second induction heating element 37 to generate heat, The heat is conducted from the lower surface of the inner pot through the inner pot wall portion to heat the cooked rice in the inner pot 3. In addition, at the time of rice cooking, the heat insulation heater 16 and the lid | cover heater 26 can be cooperated as needed, and the inner pot 3 can be heated also from a side peripheral part, an upper part, etc.

  During cooking, in particular, the heat generation temperature of the first induction heating element 36 reaches a maximum of about 220 ° C. to 230 ° C., and the high temperature heat from the first induction heating element 36 is radiated downward. Since the above-described heat insulating plate 5 is installed below the first induction heating element 36, the radiant heat does not directly heat the inner case bottom wall portion 13. Therefore, the inner case bottom wall portion 13 is not excessively heated, and the first work coil 41 below the inner case bottom portion does not rise abnormally.

  As for the second work coil 42, even if there is no heat insulating plate in the second induction heating element 37 portion, the amount of heat generation is small as described above, and since it is open to the outside, the temperature rises abnormally. There is no.

  On the other hand, at the time of cooking, the heat insulating plate 5 is gradually heated by the radiant heat from the second induction heating element 37, and when the cooking is completed, the heat insulating plate 5 is in a considerably high temperature state (much higher than the temperature of 110 ° C. at the time of unevenness). ). Since the heat insulating plate 5 has a property (heat storage property) that is difficult to cool once the temperature is raised, even if the work coils 41 and 42 are turned off (or low output) when cooking is completed, the heat insulating plate 5 remains in a high temperature state for a certain period of time. Is maintained.

  Then, after the cooking is completed, the process proceeds to a smoothing process (for example, the work coils 41 and 42 are OFF and low output, the heat retaining heater 16 and the lid heater 26 are ON, and the cooked cooked rice is maintained at about 110 ° C. for several minutes). However, at that time, the heat-insulating plate 5 whose temperature is raised releases heat, and the radiant heat heats the bottom 31 of the inner pot 3 in a supplemental but effective manner. That is, this heat insulation plate 5 can be effectively used as an auxiliary heating source for the inner pot 3 in addition to the above heat insulation function (thus saving energy).

  In particular, in the case where an inner pot is used for the inner pot 3, the thickness of the inner pot bottom 31 (and the curved portion 32) where the induction heating elements 36 and 37 are provided in order to increase the thermal conductivity at the time of rice cooking is relatively large. Although it is thin (for example, about 4 mm), in such a thin part, the amount of heat storage (residual heat) after completion of cooking is small, so it is the residual heat stored in the heat insulating plate 5 as described above. When the inner pot bottom 31 is heated, “spotting” can be performed more satisfactorily.

  Moreover, when the thing made from a ceramic or a natural stone is used as the heat insulation plate 5, when this heat insulation plate 5 is heated, far infrared rays will be emitted, and the heating effect by the far infrared rays can also be expected.

<Second Embodiment>
Next, FIG. 3 has shown the structure of the heat insulation plate which concerns on the 2nd Embodiment of this invention.

  This 2nd Embodiment shows the modification of the heat insulation plate of 1st Embodiment shown in the said FIG. The heat insulating plate 5 of the second embodiment is opposed to the central heat insulating plate part 5a facing the first induction heating element 36 of the inner pot bottom 31 and the second induction heating element 37 of the inner pot bending part 32. The one formed integrally with the overhanging heat insulating plate portion 5b is used. In addition, the heat insulation plate 5 of this 2nd Embodiment is also shape | molded by the high heat storage material like a ceramic or a natural stone similarly to the case of 1st Embodiment.

  That is, the heat insulating plate 5 of the second embodiment is installed (adhered) on the upper surface of the inner case bottom wall portion 13, and the central heat insulating plate portion 5 a is the inner pot bottom portion facing portion 13 a of the inner case bottom wall portion 13. While being located above (position facing the first induction heating element 36), the heat insulating plate portion 5b protruding to the outer peripheral side is above the curved portion facing portion 13b of the inner case bottom wall portion 13 (second induction heat generation). (Position facing the body 37).

  Moreover, in this 2nd Embodiment, since the bottom part (high plateau part 34) of the inner pot 3 is mounted on the heat insulation plate 5, several places of the circumferential direction of the position where the high plateau part 34 in this heat insulation plate 5 respond | corresponds. Spot-shaped receiving members (for example, rubber) 13c are fitted in (for example, three locations).

  The heat insulating plate 5 used in the second embodiment integrally forms the central heat insulating plate portion 5a and the overhanging heat insulating plate portion 5b. However, in other embodiments, the overhanging heat insulating plate is used. You may employ | adopt the separate thing which isolate | separated the part 5b from the center heat insulation plate part 5a.

  In the heat insulating plate 5 used in the second embodiment, the first induction heating element 36 and the second induction heating element 37 each have a heat insulating plate portion made of a high heat storage material at a corresponding portion. Therefore, the area of the heat storage part by the heat insulation plate 5 can be further increased (the amount of heat storage can be increased). Therefore, there is a merit that the auxiliary heating amount for the inner pot bottom (31, 32) from the heat insulating plate 5 (large area) can be increased in the unevenness process (or heat retention process) after the completion of cooking.

  In particular, the curved portion 32 of the inner pot 3 is relatively thin (for example, about 4 mm) similarly to the inner pot bottom portion 31, and thus has a relatively low heat storage property. If the heat insulation plate part 5b is made to oppose, it will become possible to carry out auxiliary heating from the overhang | bath insulation heat plate part 5b also with respect to the inner pot curved part 32 at the time of a nonuniformity process.

  In addition, when there is much auxiliary heating amount by the heat insulation plate 5 at the time of an unevenness process etc. in this way, the unevenness process after cooking can be performed more favorably, and it will become further energy saving.

  In the second embodiment, the overhanging heat insulating plate portion 5b of the heat insulating plate 5 is interposed between the second induction heating element 37 and the second work coil 42 of the inner pot bending portion 32. The overhanging heat insulating plate portion 5b can prevent the radiant heat from the second induction heating element 37 from being transmitted to the second work coil 42 side, and therefore, the temperature rise of the second work coil 42 can be prevented.

<Third Embodiment>
Next, FIG. 4 and FIG. 5 have shown the structure of the heat insulation plate which concerns on the electric rice cooker of 3rd Embodiment of this invention.

The third embodiment is a modification of the heat insulating plate 5 of the first embodiment shown in FIG.
And the heat insulation plate 5 of this 3rd Embodiment is installed only in the part facing the 1st induction heating body 36 similarly to the thing of the said 1st Embodiment.

  That is, the heat insulating plate 5 of the third embodiment uses a conductive material layer 53 capable of self-heating between the transparent ceramic layer 51 on the upper surface side and the heat insulating material layer 52 on the lower surface side. ing.

  Although ceramics such as cordierite are generally colored, transparent ceramics have also been developed as special ones. In the third embodiment, the transparent ceramic layer 51 is employed on the upper surface side of the heat insulating plate 5. Yes. Of course, this transparent ceramic layer 51 is also a high heat storage material like the above-mentioned ceramic material, and has a property (heat storage) that is difficult to cool once it is heated.

  On the other hand, the heat insulating material layer 52 on the lower surface side of the heat insulating plate 5 is made of a normal heat insulating material such as ceramic or natural stone. And this heat insulating material layer 52 also has a high heat storage power.

  In this embodiment, the conductive material layer 53 is provided on the lower surface of the transparent ceramic layer 51. The conductive material layer 53 may be provided on the upper surface of the heat insulating material layer 52.

  The conductive material layer 53 is formed in silver by coating, for example, an aluminum material or a metal oxide on the lower surface of the transparent ceramic layer 51 (or the upper surface of the heat insulating material layer 52). The conductive material layer 53 is formed to be extremely thin, and a small part of the alternating magnetic field generated from the first work coil 41 when energized acts on the conductive material layer 53 (the conductive material layer 53 is However, most of the alternating magnetic field is transmitted through the conductive material layer 53. Therefore, at the time of rice cooking (when energized), the conductive material layer 53 portion of the heat insulating plate 5 is supplementarily heated by a part of the alternating magnetic field from the second work coil 42, while the alternating magnetic field is mostly used. The first induction heating element 36 described above can sufficiently generate heat.

  Therefore, in the electric rice cooker according to the third embodiment, when the rice cooking switch is turned on, the first and second induction heating elements 36 are caused by the alternating magnetic fields from the first and second work coils 41 and 42, respectively. , 37 generate heat to heat the lower part of the inner pot 3, while the conductive material layer 53 of the heat insulating plate 5 is heated by a part of the alternating magnetic field from the first work coil 41 to assist the heat insulating plate 5 as a whole. Will begin to heat up.

  Therefore, the inner pot bottom 31 can be supplementarily heated by the radiant heat (indicated by the dotted arrow P in FIG. 5) from the heat insulating plate 5 that is self-heated during rice cooking, and heat can be reliably stored in the heat insulating plate 5. In addition, the heat stored in the heat insulating plate 5 is used to heat the inner pot bottom 31 in the stripping process or the like as described above.

  In addition, when cooking rice, the radiant heat from the first induction heating element 36 is radiated downward, and the conductive material layer 53 of the heat insulating plate 5 is coated with silver or aluminum oxide as described above. When it is used, the radiant heat from the first induction heating element 36 is efficiently reflected upward by the conductive material layer 53 as shown by the solid arrow P in FIG. Furthermore, it can be expected to heat efficiently.

  Therefore, the transparent ceramic layer 51 portion and the heat insulating material layer 52 portion of the heat insulating plate 5 have high heat storage properties, respectively, and even if the work coil 41 is turned off after the completion of cooking, the heat insulating plate 5 maintains a considerably high temperature state. Even in the third embodiment, the inner pot bottom 31 can be auxiliary-heated by the heat storage force of the heat insulating plate 5 in the uneven process or the like.

<Fourth Embodiment>
Furthermore, FIG. 6 and FIG. 7 have shown the structure of the heat insulation plate which concerns on the electric rice cooker of 4th Embodiment of this invention.

  This 4th Embodiment shows the modification of the heat insulation plate 5 of 3rd Embodiment shown in the said FIG.5 and FIG.6.

  In the heat insulating plate 5 of the fourth embodiment, a large number of carbon materials 54, 54... Having a small area (for example, a diameter of about several millimeters) are formed in the conductive material layer 53 portion between the transparent ceramic layer 51 and the heat insulating material layer 52. Are arranged in a state of being scattered over the entire area of the heat insulating plate 5 (conductive material layer 53), for example, as shown in FIG. The carbon material 54 may be previously kneaded in a predetermined amount into a conductive material (silver paste), and the conductive material layer 53 may be formed of the carbon material-containing conductive material. .

  The carbon material 54 has a property of emitting far-infrared rays when heated, and the conductive material layer 53 generates heat due to an alternating magnetic field from the first work coil 41 during rice cooking, or from the first induction heating element 36. When the heat insulating plate 5 is heated by radiant heat, a large amount of far-infrared rays are emitted from the carbon materials 54, 54. The far infrared rays emitted from the carbon materials 54, 54... Are radiated from the upper surface of the heat insulating plate 5 toward the inner pot bottom 31 to heat the inner pot bottom 31.

  Therefore, in the heat insulation plate 5 of this 4th Embodiment, since the heating effect by the far infrared rays from the carbon material 54 is further added, rice can be cooked still more deliciously.

It is a longitudinal cross-sectional view which shows the basic composition of the electric rice cooker main body common to each embodiment of this invention. It is sectional drawing which shows the structure of the principal part of the heat insulation plate of the electric rice cooker which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the structure of the principal part of the heat insulation plate of the electric rice cooker which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the structure of the principal part of the heat insulation plate of the electric rice cooker which concerns on 3rd Embodiment of this invention. It is the expanded sectional view which expanded a part of FIG. It is sectional drawing which shows the structure of the principal part of the heat insulation plate of the electric rice cooker which concerns on 4th Embodiment of this invention. FIG. 7 is a plan view of a part of FIG. 6.

Explanation of symbols

  1 is a rice cooker body, 2 is a lid unit, 3 is an inner pot (earthen pot), 5 is a heat insulating plate, 11 is an outer case, 12 is an inner case, 13 is a bottom wall of the inner case, 31 is an inner pot bottom, 32 Is the curved portion of the inner pot, 33 is the side wall of the inner pot, 36 is the first induction heating element, 37 is the second induction heating element, 41 is the first work coil (electromagnetic induction heating means), and 42 is the first 2 is a work coil (electromagnetic induction heating means), 51 is a transparent ceramic layer, 52 is a heat insulating material layer, 53 is a conductive material layer, and 54 is a carbon material.

Claims (5)

A non-metallic material inner pot provided with an induction heating element at the bottom, a rice cooker body having a bottomed cylindrical inner case and capable of accommodating the inner pot in the inner case so as to be removable. In the electric rice cooker provided with electromagnetic induction heating means for electromagnetically heating the inner pot through the induction heating element below the bottom wall portion of the inner case,
An electric rice cooker characterized in that a heat insulating plate made of a highly heat storage material that is magnetically permeable and has a high heat storage property is installed at a portion of the bottom wall portion of the inner case facing the induction heating element. vessel.   The electric rice cooker according to claim 1, wherein a heat reflecting surface for reflecting heat from the induction heating element is provided on a lower surface side of the heat insulating plate.   The electric rice cooker according to claim 1 or 2, wherein a conductive material layer is provided on the heat insulating plate so that the heat insulating plate itself generates heat by an alternating magnetic field from electromagnetic induction heating means.   The electric rice cooker according to any one of claims 1 to 3, wherein a carbon material that emits far infrared rays is mixed in the heat insulating plate.   A second induction heating element for providing electromagnetic induction heating to the second induction heating element below the bending part on the outer periphery of the bottom wall portion of the inner case while providing the second induction heating element on the bending portion on the outer periphery of the inner pot bottom. A heat insulating plate made of a magnetically permeable and highly heat-storing material is also installed in a portion of the curved portion of the outer periphery of the inner case bottom wall that faces the second induction heating element. The electric rice cooker of any one of Claim 1 to 4 characterized by the above-mentioned.

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