JP5338497B2 - Electromagnetic induction heating type electric rice cooker inner pot - Google Patents

Description

  The present invention relates to the structure of an inner pot for an electromagnetic induction heating type electric rice cooker, particularly an inner pot for a pottery type electromagnetic induction heating type electric rice cooker generally called a clay pot.

  Recently, electromagnetic induction heating provided with an inner pot, a rice cooker main body in which the inner pot is stored, and an induction heating coil that is arranged to face the outer peripheral surface of the inner pot and induction-heats the inner pot. Type electric rice cooker, wherein the inner pot is composed of a highly heat-stored ceramic (ceramic material), and the outer peripheral surface facing the induction heating coil when housed in the rice cooker body of the inner pot An electromagnetic induction heating type electric rice cooker in which an inner pot heating member made of a metal material capable of electromagnetic induction heating is joined to a portion is provided.

  In the inner pot used in such an electromagnetic induction heating type electric rice cooker, there is one in which a fluororesin is applied on the inner peripheral surface side so as not to cause sticking of rice and scorching (for example, (See Patent Document 1).

  In the inner pot having such a configuration, when the rice cooking operation is started by the ON operation of the rice cooking start switch, a high-frequency current is supplied to the induction heating coil according to a predetermined procedure. And by the alternating magnetic field which generate | occur | produces in the said induction heating coil, the inner pot heating member of the inner pot outer peripheral part facing the same induction heating coil couple | bonds so that electromagnetic induction is possible, and an eddy current flows.

  The inner pot heating member generates heat due to the Joule heat generated by the eddy current, and the heat is transmitted to the inner pot, and the rice and water are passed through the fluororesin coating layer applied to the inner peripheral surface of the inner pot. Heat. At this time, part of the heat is transferred from the bottom part of the inner pot to the side wall part through the inner pot base material, and the entire inner pot is warmed to uniformly heat rice and water.

  In addition, since the inner peripheral surface of the inner pot is coated with a fluororesin, the required water generation is ensured, so that an inner pot that is less likely to adhere to rice is obtained.

  However, in the case of a configuration in which a fluororesin is coated, there is a problem that the fluororesin easily peels off from the surface of the ceramic substrate and lacks durability and reliability.

  Accordingly, in response to such a situation, for example, an alumina film containing a metal oxide is formed on the surface of the ceramic pan, and a fluororesin is applied to the upper surface side through the alumina film and baked, thereby obtaining a fluororesin film. There has also been proposed one in which the above is formed (see, for example, Patent Document 2).

  According to such a configuration, since the alumina film is formed after sandblasting the surface of the ceramic pan, the adhesion of the alumina film to the ceramic pan is increased, so the ceramic pan and the fluororesin Can also be improved to some extent.

  However, in the case of the configuration of the above-mentioned Patent Document 2, even if the adhesion between the alumina film and the ceramic pan is improved, alumina is a ceramic to the last, and even if a metal is mixed, a characteristic equivalent to that of a metal cannot be produced. . Therefore, it is difficult to say that the adhesion with the ceramic pan is necessarily sufficiently high. In particular, if the target ceramic pan is in an unglazed state, if the surface has a glaze layer, the degree of adhesion is more difficult to improve.

  Further, the fluororesin film is merely applied on the alumina film, and even if it is finally fired, reliable adhesion is not always maintained between the two. Therefore, there still remains a problem that the adhesion state is not stable and is easily peeled off.

  In addition, in order to form a ceramic film such as alumina on the surface of the ceramic pan, it is necessary to perform thermal spraying with a narrow width using an expensive and large-scale thermal spraying machine such as a plasma spraying machine or a metallicon spraying machine. Moreover, it cannot be sprayed using an inexpensive arc sprayer.

  Therefore, in order to solve such a problem in forming the fluororesin coat layer, the inventor of the present invention forms the base portion of the inner pot with the ceramics as described above, and the predetermined inner surface of the base of the inner pan. A glaze layer is formed, and a metal sprayed layer is formed thereon. Then, by forming a fluororesin coat layer on the upper surface of the metal sprayed layer, the adhesion of the fluororesin to the metal sprayed layer is increased, preventing the sticking and scorching of rice, and its reliability and durability. Has proposed an inner pot for an electromagnetic induction heating type electric rice cooker that improves the performance (see, for example, Patent Document 3).

  According to such a configuration, since the fluororesin coat layer is further formed on the surface of the glaze layer via the metal sprayed layer, it is far from the inner peripheral surface of the rice compared to the case of only the glaze layer. Non-adhesiveness increases, and rice sticking and burning are less likely to occur.

  In addition, since the fluororesin coating layer is coated via the metal sprayed layer, the degree of adhesion is greatly improved compared to the conventional case, and peeling is less likely to occur. In the case of the fluorine coating layer of Patent Document 2, In comparison, it is much more reliable.

JP-A-2005-413 JP 2008-279083 A Japanese Patent Application No. 2009-96100 Specification and Drawing

  However, when the metal sprayed layer is formed as in Patent Document 3, it has been found that there are the following problems.

  That is, for example, when a metal spray layer is formed on the inner peripheral surface of the inner pan using a metal sprayer such as an arc sprayer, as shown in FIG. 5, the metal sprayer is rotated while the inner pan 1 is rotated around the axis. The thermal spray nozzle is sprayed while changing the direction (nozzle angle of the thermal spray nozzle) sequentially from the side wall portion 1c of the inner pot 1 to the R surface portion 1b and the bottom wall portion 1a.

  However, in this case, when the thermal spray nozzle is directed to the side wall 1c at an angle as shown in the drawing, the metal material a discharged toward the side wall is sprayed and applied to the inner peripheral surface of the side wall 1c. A part b thereof is reflected toward the R surface portion 1b.

  Thereafter, the thermal spray nozzle moves in the direction of the R surface portion 1b from the side wall portion 1c side, and the metal material is sprayed onto the R surface portion 1b portion.

  When the metal spraying of the R surface portion 1b is finished, the spray nozzle is further moved toward the bottom wall portion 1a, and the metal material c is sprayed toward the bottom wall portion 1a. Also at this time, a part d of the metal material c discharged from the spray nozzle is reflected toward the R surface portion 1b.

  As a result, when the metal sprayed layer on the inner peripheral surface of the inner pot 1 after spraying is observed, the metal sprayed layer 2c on the inner peripheral surface of the side wall 1c, the metal sprayed layer 2b on the R surface portion 1b, and the inner peripheral surface of the bottom wall 1a It was found that the metal sprayed layer 2b of the R-surface portion 1b was the thickest among the metal sprayed 2a, and the surface roughness was high as shown.

  As a result, when the induction heating coil on the outer peripheral side of the inner pot 1 is energized and the illustrated bottom wall portion 1a outer peripheral side first heating member 3a and R surface portion 1b outer peripheral side second heating member 3b generate heat, for example, FIG. As shown in FIG. 4, the metal sprayed layer 2b is thick, has a high degree of roughness (high unevenness), has a high heating efficiency on the R surface portion 1b, and bubbles are actively generated, so that an upward flow of water is likely to occur. Thus, the inner convection from the outer peripheral side to the central side indicated by the arrow in the figure is easily formed.

  As a result, the cooked rice has a concave cooked shape in which the central portion side of the surface RT is low over a wide range and the outer peripheral portion is high.

  That is, in the case of the same configuration, the heating amount on the inner pot bottom wall 1a side is insufficient, the side wall 1c side is heated strongly, and cooking unevenness occurs.

  In short, such cooking unevenness is caused by the heating performance on the R surface portion 1b side being too large between the R surface portion 1b side and the bottom wall portion 1a side of the inner pot.

  The present invention pays attention to the above points and effectively improves each heating performance, while relatively increasing the heating performance on the bottom wall portion side than the R surface portion side to generate bubbles from the bottom wall portion side. By forming the outer convection that rises from the center side opposite to the conventional one to the outer peripheral side and promoting the center part of the surface of the cooked rice, It aims at providing the inner pot for electromagnetic induction heating type electric rice cookers which eliminated the nonuniformity.

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

(1) Invention of Claim 1 This invention consists of the ceramics in which the glaze layer was formed in the surface, a metal spray layer on the surface of the glaze layer in the inner peripheral surface side, and a fluororesin coat layer on the surface of the metal spray layer , And an inner pot of an electromagnetic induction heating type electric rice cooker in which heating members for electromagnetic induction heating are provided on the outer peripheral side of the bottom wall part and the outer peripheral side of the rounded surface part, and the heating performance of the bottom wall part side Is made larger than the heating performance on the rounded surface side.

  With such a configuration, generation of bubbles from the bottom wall side rather than the rounded surface side is promoted, and effective external convection that efficiently rises from the wide range of the bottom side opposite to the conventional one to the outer peripheral rounded surface side. Thus, it is possible to cook rice in a wide range on the center side of the surface of the cooked rice. As a result, conventional cooking unevenness can be eliminated.

(2) Invention of Claim 2 This invention is the structure of the invention of Claim 1 above, by making the roughness of the metal sprayed layer on the inner peripheral surface of the bottom wall portion higher than the inner peripheral surface of the round surface portion, the bottom wall portion side. It is characterized by increased heating performance.

  According to such a configuration, the heating performance on the bottom wall side rather than the rounded surface side is increased. As a result, the generation of bubbles from the bottom wall side is promoted, and the wide range on the bottom wall side opposite to the conventional case is increased. It is possible to form an effective external convection that efficiently rises from the outer peripheral portion to the outer peripheral surface side, and good rice cooking is possible in which the center side of the surface of the cooked rice rises in a wide range. . As a result, conventional cooking unevenness can be eliminated.

  In this case, as a method of increasing the roughness of the metal spray layer on the inner peripheral surface side of the bottom wall portion than the roughness of the metal spray layer on the inner peripheral surface side of the rounded surface portion, the metal spray layer is caused by the above-mentioned cause of the spraying. A method of smoothing by polishing or blasting the surface of the metal spray layer on the rounded surface where the thickness becomes thicker and the roughness becomes larger than necessary, or by rotating the inner pan at low speed or spraying the metal material twice, and further spraying A method of increasing the roughness by increasing the thickness of the metal sprayed layer on the inner peripheral surface on the bottom wall side by replacing the material is employed.

(3) Invention of Claim 3 In this invention, in the configuration of the invention of Claim 1 or 2, the output of the electromagnetic induction heating coil on the outer peripheral surface side of the bottom wall portion is more than the electromagnetic induction heating coil on the outer peripheral surface side of the round surface portion. It is characterized by being enlarged.

  Even with such a configuration, the heating performance on the bottom wall portion side can be made larger than that on the round surface portion side, as in the case of the inventions of the first and second aspects.

  In particular, in the case of the same configuration, it becomes more effective when combined with the configuration of the invention of claim 2 above.

  As a result of the above, according to the present invention, it is possible to provide an inner pot for an electromagnetic induction heating type electric rice cooker having good rice cooking performance without uneven cooking.

It is a figure which shows the whole cross-section of the inner pot of the electromagnetic induction heating type electric rice cooker which concerns on embodiment of this invention. It is sectional drawing which shows the structure of the bottom wall part of the inner pot by the relationship with the heating means by the side of a rice cooker main body. It is sectional drawing which expands and shows the structure of the principal part of the bottom wall part of the inner pot. It is sectional drawing which expands and shows the structure of the principal part of the side wall part of the inner pot. It is a figure which shows the whole cross-section of the inner pot of the conventional electromagnetic induction heating type electric rice cooker. It is sectional drawing which shows the effect | action at the time of rice cooking of the same pot.

  1-4 has shown the structure of the inner pot of the electromagnetic induction heating type electric rice cooker which concerns on embodiment of this invention.

  This inner pot 1 is an inner pot for cooking rice having a ceramic structure generally called an earthen pot as already described. For example, the inner pot main bodies (base bodies) 1a to 1d shown in FIG. It is made of a cordierite-based ceramic material having a high heat storage property during heat retention, and includes a bottom wall portion 1a, a rounded surface portion 1b, a side wall portion 1c, an opening portion 1d, a mouth edge portion 1f, and a hill portion 1e as shown in the figure. It is formed to have a bottomed cross-sectional shape.

  A first heating member 3a is provided inside the hill portion 1e on the outer periphery of the bottom wall portion 1a, and a second heating member 3b is provided on the outer periphery of the rounded surface portion 1b continuous from the hill portion 1e of the bottom portion 1a to the side wall portion 1c. Each is integrally joined.

These first and second heating members 3a and 3b are respectively corresponding to first and second induction heating coils (work coils) C _{1 on the} electric rice cooker main body 5 (represented by a coil stand) shown in FIG. , C ₂ , which can be self-generated by eddy currents induced by C ₂ , for example, silver paste or other induction heating sheet.

And this inner pot 1 is arrange | positioned so as to oppose the said 1st, 2nd heating members 3a, 3b of the electric rice cooker main body which is not shown in figure in which the inner pot 1 is accommodated, and the inner pot 1 accommodated. And the first and second induction heating coils C ₁ and C ₂ for induction heating the housed inner pot 1 via the first and second heating members 3a and 3b. It is stored and used in the rice cooker body 5 of the electric rice cooker.

Then, in the state where the inner pot 1 is stored and set in the electric rice cooker body 5, for example, when the rice cooking operation is started by an ON operation of the rice cooking start switch, the first and second inductions are performed according to a predetermined procedure. A high-frequency current is supplied to the heating coils C ₁ and C _2, and the first and second induction heating coils C ₁ and C ₂ are generated by the alternating magnetic fields generated in the first and second induction heating coils C ₁ and C 2. The first and second heating members 3a and 3b facing ₂ are coupled so as to be capable of electromagnetic induction, and an eddy current flows.

  The first and second heating members 3a and 3b generate heat due to the Joule heat generated by the eddy current, and the heat is transmitted to the inner pot 1 inside the first and second heating members 3a and 3b. The rice and water in the inner pot 1 are heated. At this time, a part of the heat is transferred from the bottom wall portion 1a of the inner pot 1 to the rounded surface portion 1b, from the rounded surface portion 1b to the side wall portion 1c, and from the side wall portion 1c to the opening portion 1d through the main body (base) of the inner pan 1. The whole inner pot 1 is warmed and the rice and water in the inner pot 1 are heated uniformly.

  In addition, a heat retaining heater is provided on the outer periphery of the side wall 1c as necessary. And this side wall part 1c is thicker than the said bottom wall part 1a and the rounded surface part 1b, and is comprised so that the thermal storage property at the time of heat retention may become high.

  By the way, as described above, even in the case of the conventional inner pot, the inner peripheral surface of the inner pot is subjected to surface treatment such as fluororesin coating, which is an inner pot made of various ceramic base materials. It is made for the purpose of holding water absorption and the purpose of sticking rice and scorching, but the fluororesin is easy to peel off from the ceramic substrate surface, making it durable and reliable. There was a missing problem.

  Therefore, in the present embodiment, in order to solve such a problem in forming the fluororesin coat layer, the glaze layer 4a is formed on the surface of the bottom wall portion 1a, the round surface portion 1b, the side wall portion 1c and the like which are ceramic base materials. By forming the surface of the glaze layer 4a as shown in FIGS. 2 and 3, for example, as shown in FIGS. Then, after being subjected to sandblast treatment as necessary, aluminum metal sprayed layers 2a to 2c are formed thereon.

  Then, a fluororesin primer coat layer (first fluororesin coat layer) 4b and a fluororesin topcoat layer (second fluororesin coat layer) 4c are sequentially formed on the surfaces of the aluminum sprayed layers 2a to 2c. Thus, the adhesion and bonding force of the fluororesin to the aluminum sprayed layers 2a to 2c are sufficiently increased, and the reliability and durability of the rice are improved while preventing sticking and scorching of rice.

  That is, in the inner pot 1 of the present embodiment, for example, as shown in the sectional view of the bottom wall portion 1a in FIG. 3 and the sectional view of the side wall portion 1c in FIG. 4, the bottom wall portion 1a of the inner pot 1 shown in FIG. First, a desired thickness is applied to both the inner peripheral surface and the outer peripheral surface of each part of the inner pot body (base body) in an unglazed state extending from the opening 1d to the opening 1d (including the part without the heating members 3a and 3b). The lithia-based glaze layer 4a (illustration of the outer peripheral surface is omitted) is formed, thereby realizing low water permeability of the inner pot body portion at low cost. Thereafter, the inner peripheral surface side portion (portion in which rice and water are accommodated) is subjected to a predetermined blast treatment as necessary to roughen the surface of the glaze layer 4a to a predetermined roughness.

  Then, as a base treatment for forming the highly durable fluororesin coating layers 4b and 4c, aluminum metal spraying (spraying) is performed using a simple metal spraying machine such as an arc spraying machine, The aluminum sprayed layers 2a to 2c having a desired thickness along the uneven surface (rough surface) formed by the sandblasting on the surface of the glaze layer 4a are formed. The aluminum sprayed layers 2a to 2c are generated with good adhesion by effectively adhering to and engaging with the irregular surface portion of the surface of the glaze layer 4a formed by the sandblast.

  Then, a fluororesin primer coat layer (first fluororesin coat layer) 4b is first formed on top of the aluminum sprayed layers 2a to 2c, and particularly in the side wall portion 1c shown in FIG. Water scales 7, 7, and 7 are pad printed on the surface of 4b.

  Thereafter, a fluororesin top coat layer (second fluororesin coat layer) 4c is formed thereon with a desired thickness thicker than that of the primer fluororesin layer coat layer 4b, and is further baked, whereby the rice is stuck and burnt. In addition, the fluororesin is hardly peeled off, and a clear and suitable inner pot 1 with a water scale 7 is formed.

  In this case, in this embodiment, as an example, the glaze layer 4a adheres the Lithia glaze as described above to the entire inner and outer peripheral surfaces of the unglazed inner pot main bodies (substrates) 1a to 1d as necessary. The film is formed by performing a predetermined blasting process (for example, sandblasting process) to improve the coating, drying the coating, and then performing a baking process. Of course, this blasting process is not an indispensable requirement, and the necessary adhesion strength can be obtained without the blasting process. However, if the glaze layer 4a is formed after the blasting process, the inner blasting process is more effective. The adhesion strength of the glaze layer 4a to the pan body is increased.

  By the way, in the above case, as already described with reference to FIG. 5, the thickness of the metal spray layer 2b on the inner peripheral surface of the inner pot round surface portion 1b is equal to the side wall portion 1c due to the spraying method at the time of aluminum metal spraying. Further, it becomes thicker than the sprayed layers 2c and 2a in the bottom wall portion 1a, and the roughness of the surface is also increased. As a result, cooking unevenness due to insufficient heating at the center side as shown in FIG. 6 occurred.

  And, the cause is that the thickness of the metal sprayed layer 2b on the outer peripheral side surface 1b is excessively thicker than necessary, compared to the metal sprayed layer 2a having an appropriate thickness and roughness of the bottom wall 1a, and The roughness was too high.

  Therefore, in this embodiment, in order to eliminate this problem, relatively improve the heating performance on the bottom wall portion 1a side, increase the heating efficiency on the inner pan central portion side, and form an effective outer convection. By polishing or blasting the surface of the metal sprayed layer 2b on the side of the rounded surface portion 1b, the surface is smoothed to a predetermined level and its roughness is lowered.

  According to such a configuration, the heating performance on the bottom wall portion 1a side rather than the round surface portion 1b side is increased. As a result, the generation of bubbles from the bottom wall portion 1a side is promoted, and the bottom wall portion 1a opposite to the conventional one is promoted. The effective outer convection as shown in FIG. 1 that efficiently rises from the wide range of the side center to the outer peripheral rounded surface portion 1b side can be formed, and the central portion of the surface RT of the cooked rice accordingly Good cooking with a wide side is possible. As a result, conventional cooking unevenness can be eliminated.

  The metal-sprayed layer 2b made of aluminum metal has good habituation when bonded to the glaze layer 4a of the inner pot 1 and has a lower hardness than a ceramic film such as a conventional alumina. Easy.

  Further, unlike the conventional ceramic film made of alumina or the like, the aluminum metal sprayed layers 2a to 2c can be easily sprayed by a simple and inexpensive arc spraying machine. Therefore, the manufacturing cost can be reduced.

  In addition, it is as follows when the relationship of the roughness value Ra of the inner peripheral surface of the inner pot 1 in the above structure is summarized.

(1) Side wall 1c: Ra = 8 to 9 having the highest smoothness because there is no need to generate bubbles.
(2) Round surface portion 1b: Ra is 10 to 15 at a very high level at the stage of spraying before smoothing, and is polished or blasted to reduce Ra to about 7 to 8.

  (3) Bottom wall 1a: Ra is maintained at a high level of Ra = 10 to 12 in order to increase the bubble generation effect and to efficiently generate external convection.

(Other embodiments)
The gist of the present invention is that, in the inner pot made of ceramic as described above, the heating performance of the bottom wall portion 1a having a larger area than the rounded surface portion 1b is relatively improved to increase the bubble generation effect, and the inner pot 1 It is in the point which forms external convection with high rice cooking performance.

Therefore, as an effective method for that purpose, in addition to the method of smoothing the metal sprayed layer 2b of the rounded surface portion 1b as described above, in addition to the method of smoothing, the metal sprayed layer 2a on the bottom wall 1a side is also provided. The method of increasing the thickness and roughness of the metal spray layer 2a by increasing the number of times of spraying the part or increasing the spraying time, changing the material, etc., and the first induction heating coil C ₁ on the bottom wall 1a side A method such as making the output of the second side larger than the output of the second induction heating coil C ₂ on the radius surface portion 1b side is also adopted as necessary, and these are used in combination as appropriate.

DESCRIPTION OF SYMBOLS 1 is an inner pot, 1a is an inner pot bottom wall part, 1b is an inner pot round surface part, 1c is an inner pot side wall part, 1d is an inner pot opening part, 2a-2c is an aluminum sprayed layer, 3a is a 1st heating member, 3b the second heating member, 4a glaze layer, 4b fluororesin primer coat layer, 4c fluororesin topcoat layer, C ₁ is the first induction heating coil, the C ₂ is the second induction heating coil.

Claims (3)

  It is made of a ceramic with a glaze layer formed on the surface, and a metal spray layer is provided on the surface of the glaze layer on the inner peripheral surface side, and a fluororesin coat layer is provided on the surface of the metal spray layer, It is an inner pot of an electromagnetic induction heating type electric rice cooker in which a heating member for electromagnetic induction heating is provided on the outer peripheral side of the rounded face part, and the heating performance on the bottom wall part side is larger than the heating performance on the rounded face part side An electromagnetic induction heating type electric rice cooker.   2. The induction heating electric rice cooker according to claim 1, wherein the heating performance of the bottom wall portion side is increased by increasing the roughness of the metal sprayed layer on the inner peripheral surface of the bottom wall portion than the inner peripheral surface of the round surface portion. The inner pot of the vessel.   The inner pot of the electromagnetic induction heating type electric rice cooker according to claim 1 or 2, wherein the output of the electromagnetic induction heating coil on the outer peripheral surface side of the bottom wall portion is larger than the electromagnetic induction heating coil on the outer peripheral surface side of the round surface portion. .

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