JP5874000B2 - Induction heating rice cooker - Google Patents

Description

  The present invention relates to an induction heating rice cooker used for cooking rice in general households, restaurants and the like.

  Conventionally, this type of rice cooker has a heating coil that generates an induction magnetic field for heating the pot in the rice cooker, and this heating coil heats the bottom part of the pot, and the bottom of the pot There is known an induction heating rice cooker that has an outer coil disposed obliquely to heat a slope portion between the side surfaces and heats the pan three-dimensionally.

  Moreover, in the said conventional induction heating rice cooker, the lower part of a heating coil is equipped with the ferrite and the coil base which supports the said heating coil and the said ferrite, The said heating coil, the said ferrite, and the said coil base are made of resin. An induction heating rice cooker that is insert-molded and integrally molded is known (for example, see Patent Document 1).

JP 2000-61986

  However, the structure of the conventional induction heating rice cooker configured as described above requires expensive equipment such as an expensive insert molding device, and it is difficult to manufacture the rice cooker at low cost. there were.

  In addition, in the structure of the conventional induction heating rice cooker, when the inner coil and the outer coil of the heating coil are formed in a planar shape, the manufacturing cost can be reduced, but the induction magnetic field generated by the heating coil is reduced. However, it concentrated on the center of a pan bottom, the heating nonuniformity produced in the said pan, and had the subject that rice cooking performance fell.

  In addition, when the heating coil configured as described above is used, heating concentrates at the center of the pan bottom, the temperature of the side surface portion of the pan becomes difficult to rise, and temperature control becomes difficult. It had the subject that performance fell.

  The present invention solves the problems in the conventional induction heating rice cooker, and the heating coil generates an induction magnetic field in a desired state to uniformly heat the pan, so that the induction heating with improved rice cooking performance is achieved. The purpose is to provide a rice cooker.

In order to solve the problems in the conventional induction heating rice cooker, the induction heating rice cooker of the present invention is
The body,
A pan that is detachably stored in the main body;
A ring-shaped heating coil disposed opposite to the bottom of the pan and generating an induction magnetic field for heating the pan;
An inverter that applies a high-frequency current to the heating coil;
A control unit for controlling a high-frequency current applied to the heating coil,
The heating coil has an inner peripheral portion and an outer peripheral portion, and the outer peripheral portion is configured to have a height in the vertical direction higher than that of the inner peripheral portion.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible for a heating coil to generate | occur | produce an induction magnetic field in a desired state, it becomes possible to heat a pan uniformly, and the induction heating rice cooker which improved rice cooking performance can be provided.

Side sectional view of induction heating rice cooker according to the first embodiment of the present invention. The top view and sectional side view of a heating coil in the induction heating rice cooker of Embodiment 1 which concerns on this invention.

The induction heating rice cooker according to the first aspect of the present invention is:
The body,
A pan that is detachably stored in the main body;
A ring-shaped heating coil disposed opposite to the bottom of the pan and generating an induction magnetic field for heating the pan;
An inverter that applies a high-frequency current to the heating coil;
A control unit for controlling a high-frequency current applied to the heating coil,
The heating coil has an inner peripheral portion and an outer peripheral portion, and the outer peripheral portion is configured to have a height in the vertical direction higher than that of the inner peripheral portion.

  In the induction heating rice cooker according to the first aspect of the present invention configured as described above, the heating coil can generate the induction magnetic field substantially uniformly, and the pan can be heated uniformly. As a result, the induction heating rice cooker according to the first aspect of the present invention is a rice cooker in which heating unevenness is suppressed and rice cooking performance is improved.

  Moreover, according to the induction heating rice cooker of the 1st viewpoint which concerns on this invention, it becomes possible to concentrate the induction magnetic field which a heating coil generates on the outer side of a pan, and the outer side of the said pan is concentrated and heated. By accelerating | stimulating the heat transfer from the bottom face of a pan to a side surface, the said pan is heated three-dimensionally, the said pan is heated uniformly as a result, and rice cooking performance can be improved.

  Furthermore, according to the induction heating rice cooker of the 1st viewpoint which concerns on this invention, it becomes a structure with easy shaping | molding and support of a heating coil, and it becomes possible to set it as the cheap structure which can suppress manufacturing cost.

  The induction heating rice cooker according to a second aspect of the present invention is the heating coil according to the first aspect, wherein the outer peripheral portion has a higher height in the pan direction than the inner peripheral portion, and the outer peripheral portion. The gap between the pan and the pan is configured to be smaller than the gap between the inner peripheral portion and the pan.

  In the induction heating rice cooker according to the second aspect of the present invention configured as described above, the outer peripheral portion of the heating coil is narrower than the inner peripheral portion, and the gap between the pan and the outer peripheral portion of the heating coil and the pan is reduced. And the induced magnetic field can be concentrated outside. As a result, according to the induction heating rice cooker of the 2nd viewpoint which concerns on this invention, it becomes possible to concentrate and heat the outer side of a pan, accelerate heat transfer from the bottom face of a pan to a side surface, Heating three-dimensionally, as a result, the pan can be heated uniformly to improve rice cooking performance.

  In the induction heating rice cooker according to the third aspect of the present invention, the heating coil according to the first aspect or the second aspect is formed by winding a litz wire.

  In the induction heating rice cooker of the 3rd viewpoint which concerns on this invention comprised as mentioned above, the litz wire comprised by the copper wire made by twisting a plurality of thin enamel wires as a heating coil is used. Therefore, it has the effect of preventing an increase in resistance due to the skin effect when a high-frequency current is passed through the conductor.

  In the induction heating rice cooker of the 4th viewpoint which concerns on this invention, as for the said heating coil in any aspect in the said 1st viewpoint thru | or the 3rd viewpoint, the said outer peripheral part is compared with the said inner peripheral part, The number of turns per unit length in the radial direction is increased.

  The induction heating rice cooker of the 4th viewpoint which concerns on this invention comprised as mentioned above makes it possible to generate | occur | produce an induction magnetic field substantially uniformly in a heating coil, and to heat a pan uniformly. As a result, the induction heating rice cooker of the 4th viewpoint which concerns on this invention turns into a rice cooker by which the heating nonuniformity was suppressed and the rice cooking performance improved.

  Moreover, the induction heating rice cooker of the 4th viewpoint which concerns on this invention can concentrate the induction magnetic field which a heating coil generate | occur | produces on the outer side, and concentrates and heats the outer side of a pan from the bottom face of a pan. Heat transfer to the side surface can be accelerated to heat the pan three-dimensionally, and as a result, the pan can be heated uniformly to improve rice cooking performance.

  In the induction heating rice cooker of the 5th viewpoint which concerns on this invention, in any aspect in the said 1st viewpoint thru | or a 4th viewpoint, the said pot accommodated in the said main body and the said heating coil are included. The protective frame is configured by a metal material having a low magnetic permeability.

  In the induction heating rice cooker of the 5th viewpoint which concerns on this invention comprised as mentioned above, the electric current opposite to the electric current which flows into a heating coil flows into a protective frame with the induction magnetic field which a heating coil generates. As a result, in the induction heating rice cooker according to the fifth aspect of the present invention, the protective frame generates an induction magnetic field opposite to the induction magnetic field generated by the heating coil, and the induction magnetic fields cancel each other out. A magnetic shielding effect can be obtained by the frame.

  In addition, in an induction heating rice cooker, heat energy radiated from the pot in accordance with the Stefan-Boltzmann law is proportional to the fourth power of the temperature. Therefore, when the temperature of the pot becomes high in the rice cooking process, the radiation of heat energy increases. . However, in the induction heating rice cooker according to the fifth aspect of the present invention, a protective frame is provided on the outside of the pan, and the protective frame is a low permeability metal material, so the reflectance is high, It is possible to reflect the heat energy and return it to the pan. As a result, the induction heating rice cooker of the 5th viewpoint which concerns on this invention can further improve the heating efficiency of a pan, and has the structure which can aim at the further improvement of rice cooking performance.

  In the induction heating rice cooker of the 6th viewpoint which concerns on this invention, in either aspect in the said 1st viewpoint thru | or a 5th viewpoint, Between the said pan accommodated in the said main body and the said heating coil Is provided with a partition plate.

  In the induction heating rice cooker according to the sixth aspect of the present invention configured as described above, heat generated by the loss of the heating coil can be transferred to another member (such as a pan) via the partition plate. It becomes. Moreover, it becomes possible to hold | maintain the space | interval between a heating coil and a pan | pan at a predetermined distance reliably by providing a partition plate.

  Furthermore, in the induction heating rice cooker of the 6th viewpoint which concerns on this invention, since the partition plate is provided, it becomes possible to make a heating coil in the bottom face of a pot accommodating part invisible to a user, and it is safe. It is possible to improve the design (shape) of the pot storage part as well as ensuring the performance.

  Moreover, in the induction heating rice cooker of the 6th viewpoint which concerns on this invention, when the protective frame is provided like the induction heating rice cooker of the said 5th viewpoint, the heat_generation | fever by the loss of a heating coil, The configuration is easy to convey to the protective frame via the partition plate. Since the protective frame is a metal material, it has a high thermal conductivity and the temperature is likely to be uniform. Therefore, the induction heating rice cooker according to the sixth aspect of the present invention generates heat due to the loss of the heating coil. And it becomes possible to heat a pan uniformly through a protective frame, and it becomes possible to aim at the further improvement of rice cooking performance.

  Hereinafter, an embodiment according to the induction heating rice cooker of the present invention will be described in detail with reference to the accompanying drawings. In addition, the induction heating cooker of this invention is not limited to the structure of the induction heating cooker described in the following embodiment, The technical idea equivalent to the technical idea demonstrated in the following embodiment The induction heating rice cooker comprised based on is included.

(Embodiment 1)
FIG. 1 shows a side sectional view of an induction heating rice cooker according to Embodiment 1 of the present invention.

  In FIG. 1, the main body 1 is formed in a substantially cylindrical shape whose upper surface is open, and includes a protective frame 10 serving as a pot storage portion inside the main body 1. Inside the protective frame 10, a pan 2 having a water level line drawn on its inner peripheral surface is detachably disposed. The protective frame 10 is provided inside the main body 1 so as to enclose the heating coil 5 together with the pot 2. The protective frame 10 is made of a low permeability metal material.

  As described above, in the induction heating rice cooker of the first embodiment, a current opposite to the current flowing through the heating coil 5 flows through the protective frame 10 due to the induction magnetic field generated by the heating coil 5. As a result, in the protective frame 10, an induction magnetic field opposite to the induction magnetic field generated by the heating coil 5 is generated, so that the magnetic fields from the heating coil 5 cancel each other, and the protective frame 10 has a magnetic shielding effect. It will be a thing.

  In addition, in the induction heating rice cooker, heat energy proportional to the fourth power of temperature is radiated from the pot 2 in accordance with the Stefan-Boltzmann law. Will increase. However, in the induction heating rice cooker of the first embodiment, the protective frame 10 is provided on the outside of the pan 2, and the protective frame 10 is a metal material having a low magnetic permeability. The heat energy from is reflected back to the pan. As a result, in the induction heating rice cooker of Embodiment 1, since the protective frame 10 made of a low magnetic permeability metal material, for example, an aluminum material, is provided, the heating efficiency of the pan 2 is improved, and rice cooking is performed. The performance is improved.

  In the induction heating rice cooker of the first embodiment, the heating coil 5 is disposed to face the bottom surface of the pan 2 housed in the protective frame 10 and generates an induction magnetic field for heating the pan 2. It has a ring shape. A ferrite 14 is provided on the lower surface of the heating coil 5 to converge the induction magnetic field generated by the heating coil 5. A partition plate 15 is provided between the pan 2 and the heating coil 5.

  As shown in FIG. 1, in the induction heating rice cooker of the first embodiment, the partition plate 15 is disposed between the heating coil 5 and the pan 2, and the partition plate 15 and the outer peripheral portion 5b of the heating coil 5 are arranged. The upper surface (the surface facing the pan 2) is in contact with the heat transfer. In addition, since the partition plate 15 is in contact with the protective frame 10 so that heat can be transferred at the outer peripheral portion thereof, the heat energy generated by the loss of the heating coil can be transmitted to the protective frame 10 via the partition plate 15. is there.

  In the induction heating rice cooker according to the first embodiment, the protective frame 10 is made of a metal material with low magnetic permeability, has a high thermal conductivity, and has a characteristic that the temperature tends to be uniform. The heat energy of the heat generated by the loss is transferred to the pan 2 through the partition plate 15 and the protective frame 10, and it becomes possible to assist the uniform heating of the pan 2 and further improve the rice cooking performance. it can.

  As described above, in the induction heating rice cooker according to the first embodiment, heat generated by the loss of the heating coil is transferred to other members such as the pan and the protective frame 10 through the partition plate 15. The partition plate 15 is also used as a heat transfer member. In addition, in the induction heating rice cooker of Embodiment 1, since the partition plate 15 is provided, it becomes possible to hold | maintain the space | interval between the heating coil 5 and the pan 2 to a predetermined distance reliably.

  Furthermore, in the induction heating rice cooker of Embodiment 1, since the partition plate 15 is provided, the heating coil 5 on the bottom surface of the pan storage portion is not visible to the user, ensuring safety and the pan. The design (look) of the storage part is improved.

  Moreover, the control part 8 is provided in the inside of the main body 1, and the control part 8 controls the inverter 7 to apply the high frequency current to the heating coil 5, so that the pan 2 housed in the protective frame 10 is removed. Heat.

  A lid 3 is attached to the upper portion of the main body 1 so as to be freely opened and closed. The lid 3 is supported so as to be rotatable around a hinge 3a located at a rear portion of the protective frame 10 (the end portion on the back side of the lid 3 and the right end portion in FIG. 1). The lid 3 is urged to be opened by a rotating spring. At the other end (the left end in FIG. 1) of the lid 3 facing the hinge 3a, a hook button (not shown) pivotally supported on the front portion of the protective frame 10 is disposed. The hook button is fitted to the lid 3 so that the lid 3 is closed. That is, when the hook button is fitted to the lid 3, the lid 3 is not held open and is securely held by the hook button, and the pot storage portion is closed.

  An inner lid 4 having a steam port 4b for discharging steam generated in the pan 2 during rice cooking and heat insulation is disposed at the lower part of the lid 3. A cylindrical steam tube 11 communicating with the outside of the main body through a steam tube port 11a is disposed at the upper portion of the inner pot 4.

  A steam port packing 6 is disposed between the steam cylinder 11 and the inner lid 4 to prevent the steam from flowing into the lid 3. In addition, an inner lid packing 4a that is in contact with the upper surface of the flange portion (not shown) of the pan 2 is disposed on the outer peripheral portion of the inner lid 4, and steam generated in the pan 2 during cooking and heat retention. It is prevented from flowing outside from the steam port 4b.

  The pan temperature detection unit 9 is in contact with the substantially central portion of the bottom surface of the pan 2 and detects the temperature of the pan 2 by heat conduction. The lid temperature detector 12 is in contact with the inner lid 4 and detects the temperature of the pan 2 by heat conduction.

  The operation display unit 13 receives a heating condition by an operation by the user, and displays and notifies the user of the state of the rice cooker.

  In addition, in the induction heating rice cooker of Embodiment 1, the main body 1, the lid | cover 3, and the steam cylinder 11 have a resin case, the partition plate 15 has a resin plate, and the pan 2 has a metal pan such as iron or SUS. A metal lid for the inner lid 3, a rubber packing for the inner lid packing 4a and the steam port packing 6, a litz wire for the heating coil 5, a high-frequency inverter for the inverter 7, and a high-frequency inverter for the control unit 8. The microcomputer can be easily configured by using a thermistor for the pan temperature detection unit 9 and the lid temperature detection unit 12, an aluminum material for the protective frame 10, and a touch panel for the operation display unit 13.

  FIG. 2: shows the top view and side sectional drawing of a heating coil in the induction heating rice cooker of Embodiment 1 which concerns on this invention.

  Conventionally, in a heating coil formed by winding a metal conductor into a ring shape, a magnetic flux of an induced magnetic field is generated around the coil in the radial direction of the heating coil. Moreover, since the heating coil is ring-shaped, magnetic flux is concentrated in the inner peripheral part compared with the outer peripheral part.

  In FIG. 2, the heating coil 5 in the induction heating rice cooker of Embodiment 1 is formed by winding a twisted litz wire into a ring shape, and the outer peripheral portion 5b of the heating coil 5 is compared with the inner peripheral portion 5a. Thus, the height L (see FIG. 2) is increased.

  Since the litz wire is a stranded wire, the width in the radial direction of the heating coil 5 changes according to the height, and the width becomes narrower when the height is high. Therefore, the outer peripheral portion 5b has a larger number of turns per unit length in the radial direction than the inner peripheral portion 5a. That is, the outer peripheral portion 5b has a higher coil density than the inner peripheral portion 5a. The litz wire is a copper wire formed by twisting a plurality of thin enamel wires, and has an effect of preventing an increase in resistance due to a skin effect when a high-frequency current is passed through a conductor.

  Therefore, the induction magnetic field generated by the heating coil 5 can be generated substantially uniformly by changing the heights of the inner peripheral portion 5a and the outer peripheral portion 5b to appropriate heights. In addition, by increasing the height of the outer peripheral portion 5b in the heating coil 5, the induction magnetic field generated by the heating coil 5 can be concentrated on the outer portion.

  As shown in FIG. 2, in the induction heating rice cooker of Embodiment 1, the outer peripheral part 5b in the heating coil 5 is higher in the vertical direction (upward direction in FIG. 2) of the pan 2 than the inner peripheral part 5a. It is configured to increase the length L and approach the pan 2. In the induction heating rice cooker of the first embodiment, as shown in FIG. 2, the heating coil 5 has a planar shape, and the lower surface (ferrite 14) in the vertical direction of the inner peripheral portion 5 a and the outer peripheral portion 5 b. The surface in contact with the surface is substantially the same plane. On the other hand, on each upper surface (surface facing the pan 2) in the vertical direction of the inner peripheral portion 5a and the outer peripheral portion 5b, the outer peripheral portion 5b is compared to the inner peripheral portion 5a with respect to the pan 2, as described above. It is configured to approach. Therefore, the space | gap (gap) of the outer peripheral part 5b and the pan 2 is smaller than the space | gap (gap) of the inner peripheral part 5a and the pan 2, and the magnetic coupling between the outer peripheral part 5b and the pan 2 becomes strong. ing.

  By using such a configuration, the outer peripheral portion 5b of the heating coil 5 is narrower than the inner peripheral portion 5a so that the gap between the pan 2 and the heating coil 5 and the pan 2 is improved. It is possible to concentrate the induction magnetic field on the outer portion of the heating coil 5.

  Next, the operation and action of the induction heating rice cooker of Embodiment 1 configured as described above will be described.

  The rice cooking process of the induction heating rice cooker according to the first embodiment includes a submersion process in which water is absorbed by the rice, a cooking process in which the temperature in the pan is increased and boiled at once, and the starch is gelatinized by maintaining boiling. The boiling maintaining process to make it into rice and the unevenness process to finish the inside of the pan uniformly by steaming the cooked rice, and the control method in each process is stored in the control unit 8.

  First, after a user puts a predetermined amount of rice and water into the pan 2 and sets the pan 2 on the main body 1, the user performs an operation for starting rice cooking using the operation display unit 13, and a command signal for starting rice cooking is received. It is transmitted to the control unit 8. If the control part 8 receives the command signal of a rice cooking start, the control part 8 will start a water immersion process.

  The water immersion process is a process that allows the rice to be sufficiently gelatinized in the subsequent steps by immersing the rice in water at a temperature lower than the temperature at which the rice is gelatinized and preliminarily absorbing the rice. .

  The water immersion process is also a process of degrading starch with amylase contained in rice to produce glucose, thereby producing rice sweetness. For this reason, in a water immersion process, it controls so that the detection temperature of the pan temperature detection part 9 may be about 60 degreeC for predetermined time (for example, 20 minutes).

  That is, the control unit 8 performs temperature detection by the pan temperature detection unit 9, and if the temperature detection information from the pan temperature detection unit 9 is 60 ° C. or less, operates the inverter 7 to apply a high frequency current to the heating coil 5. Then, the pan 2 is heated. On the other hand, if the detected temperature information is 60 ° C. or higher, the inverter 7 is operated to stop the current application to the heating coil 5 and the heating of the pan 2 is stopped.

  When a predetermined time has elapsed from the start of the water immersion process, the process proceeds to the cooking process.

  In the cooking process, the pan 2 is heated until the detected temperature information from the pan temperature detecting unit 9 is close to the boiling point of water (for example, 100 ° C.). At this time, the amount of the cooking object, that is, the amount of cooked rice can be determined based on the difference in temperature gradient in the time transition of the detected temperature.

  When the detected temperature information from the pan temperature detector 9 reaches a predetermined temperature, the process proceeds to the boiling maintenance step.

  The boiling maintaining step is a step of gelatinizing rice starch to raise the degree of gelatinization to about 50% to 60%. In the boiling maintenance process, the controller 8 operates the inverter 7 to apply a high-frequency current to the heating coil 5 so that the rice and water in the pot 2 maintain a boiling state while the pot 2 has water, The pan 2 is heated.

  In this heating operation, when the water in the pot 2 is absorbed by the rice and disappears due to evaporation, the temperature of the pot 2 rises rapidly. When the temperature detected by the pan temperature detection unit 9 reaches a predetermined temperature (for example, 130 ° C.), the boiling maintenance process is terminated and the process proceeds to the unevenness process.

  The unevenness process is a process in which starch of rice is gelatinized to increase the degree of gelatinization to nearly 100%. In the spotting process, while preventing the bottom of the pan from scorching, the temperature of the rice is prevented from lowering, and gelatinization is promoted to make the rice in the pan 2 uniform. In response to this, the heating operation is turned on / off so that the temperature of the pan temperature detection unit 9 is maintained at a predetermined temperature (for example, 80 ° C.).

  In the heating operation of the pan 2 in each of the above rice cooking steps, the inner peripheral portion 5a of the heating coil 5 generates an induction magnetic field in the inner portion of the bottom surface of the pan 2, and the outer peripheral portion 5b of the heating coil 5 is the bottom surface of the pan 2. An induction magnetic field is generated in the outer portion, and each performs induction heating.

  The heat of the outer portion of the bottom surface of the pan 2 is transferred to the side portion of the pan 2 to heat the pan 2 three-dimensionally.

  Further, the heat energy of heat generated by the loss in the heating coil 5 is transmitted to the bottom surface of the protective frame 10 via the ferrite 14. The heat of the bottom surface portion of the protective frame 10 is transmitted to the side surface portion of the protective frame 10, and further transmitted to the side surface portion of the pan 2 through the air to heat the pan 2 three-dimensionally.

  As described above, in the induction heating rice cooker of the first embodiment, since the heating coil 5 and the protective frame 10 are configured by thermally connecting the ferrite 14 and the like, heat energy generated in the heating coil 5 is generated. Is used to heat the pan 2 three-dimensionally, and has an excellent effect that the pan 2 can be heated with high efficiency.

  Moreover, in the induction heating rice cooker of Embodiment 1, it has the heat insulation effect by setting it as the structure which seals between the pan 2 and the protective frame 10, and the structure which can heat the pan 2 three-dimensionally. It becomes.

  In the induction heating rice cooker of the first embodiment, the pan temperature detection unit 9 abuts on the substantially central portion of the bottom surface of the pan 2 to detect the temperature of the pan 2 by heat conduction, and the water in the pan 2 is detected from the detected temperature. The temperature of rice and rice is estimated and each rice cooking process is controlled.

  On the other hand, in the conventional induction heating cooker, since heating concentrates at the center of the pan, the configuration in which the pan temperature detection unit is brought into contact with the substantially central portion of the bottom of the pan to detect the pan temperature is biased. The temperature was detected, and it was difficult to accurately estimate the temperature of water and rice in the pan, and there was a problem that rice cooking performance was reduced.

  In the configuration of the induction heating rice cooker according to the first embodiment of the present invention, the induction magnetic field generated by the heating coil 5 can be generated substantially uniformly, and the pan 2 can be heated uniformly. . As a result, in the configuration of the induction heating rice cooker of the first embodiment, it becomes possible to accurately estimate the temperature of water or rice in the pan 2 and improve the rice cooking performance.

  In addition, in the structure of the induction heating rice cooker of Embodiment 1, although the heating coil 5 demonstrated in the structure which has two parts from which the height of the inner peripheral part 5a and the outer peripheral part 5b differs, this invention is such It is not limited to the configuration, and the heating coil is configured to have a plurality of parts having different heights, and the height is gradually increased from the inner periphery toward the outer periphery according to the shape of the pan. However, the same effect can be obtained.

  In the induction heating rice cooker of the present invention, the heating coil can generate the induction magnetic field in a desired state, for example, substantially uniformly, and as a result, the pan can be uniformly heated by the heating coil. Therefore, according to this invention, the heating nonuniformity can be suppressed and the rice cooker which the rice cooking performance improved can be provided.

  Moreover, in the induction heating rice cooker of this invention, it becomes possible to concentrate the induction magnetic field which a heating coil generate | occur | produces on the outer side of a pan. As a result, according to the present invention, it becomes possible to concentrate and heat the outside of the pan, accelerate heat transfer from the bottom surface to the side surface of the pan, and heat the pan three-dimensionally. A pot can be heated uniformly and rice cooking performance can be improved.

  Furthermore, in the structure of the induction heating rice cooker of this invention, since the heating coil is comprised planarly, it is a structure with easy shaping | molding and support of a heating coil, and can suppress manufacturing cost significantly.

  The present invention is a rice cooker in which a heating coil can generate an induction magnetic field in a desired state, a pan can be heated uniformly, heating unevenness is suppressed, and rice cooking performance is improved. Since the coil can be easily formed and supported and can be manufactured at low cost, it is useful as a rice cooker used in general households, restaurants and the like.

DESCRIPTION OF SYMBOLS 1 Main body 2 Pan 5 Heating coil 5a Inner peripheral part 5b Outer peripheral part 7 Inverter 8 Control part 10 Protection frame 15 Partition plate

Claims (5)

The body,
A pan that is detachably stored in the main body;
A ring-shaped heating coil disposed opposite to the bottom of the pan and generating an induction magnetic field for heating the pan;
An inverter that applies a high-frequency current to the heating coil;
A control unit for controlling a high-frequency current applied to the heating coil,
The heating coil is formed by winding a litz wire formed of a stranded wire, and has an inner peripheral portion for heating the inner portion of the bottom surface of the pan and an outer peripheral portion for heating the outer portion of the bottom surface of the pan. The outer peripheral portion is changed so that the radial width of the cross section of the single litz wire is narrower and the vertical height is higher than the inner peripheral portion, and the unit length in the radial direction is changed. Induction heating rice cooker configured to increase the number of windings.   In the heating coil, the outer peripheral portion is higher in height in the pan direction than the inner peripheral portion, and the gap between the outer peripheral portion and the pan is smaller than the gap between the inner peripheral portion and the pan. The induction heating rice cooker of Claim 1 comprised.   The induction heating rice cooker according to claim 1 or 2, wherein the heating coil is configured such that the outer peripheral portion has a greater number of turns per unit length in the radial direction than the inner peripheral portion.   5. The device according to claim 1, further comprising a protective frame configured to enclose the pan and the heating coil housed in the main body, wherein the protective frame is made of a low magnetic permeability metal material. The induction heating rice cooker of item 1.   The induction heating rice cooker according to any one of claims 1, 2, 4, and 5, wherein a partition plate is provided between the pan housed in the main body and the heating coil.

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