JP5691003B2 - Induction heating rice cooker - Google Patents

Description

  The present invention relates to an induction heating rice cooker used in general homes, restaurants, offices, and the like.

  Conventionally, this type of rice cooker has a heating coil that generates an induction magnetic field that heats the pan, and the heating coil includes an inner coil that heats the bottom surface of the pan and an outer coil that heats the slope between the bottom and side surfaces of the pan. And an induction heating rice cooker that heats the pan three-dimensionally is known.

  There is also known a cooking container that is a pan for an induction heating cooker in which a ferromagnetic metal plate is superposed on a flat surface outside the bottom of a cooking container made of a nonmagnetic metal material (see, for example, Patent Document 1).

International Publication No. 02/001991

  However, in order to induction-heat the pan described in Patent Document 1, it is necessary to configure the heating coil in a substantially planar shape so as to correspond to the shape of the ferromagnetic metal plate.

  In the substantially planar heating coil, the induction magnetic field generated by the heating coil is concentrated in the vicinity of the inner periphery of the heating coil. The boiling bubbles are concentrated. When boiled foam is generated by concentrating on a specific location, the boiled foam rises upward from the location where it is generated, but the swollen rice is due to the continued high moisture content at the site until the latter half of the rice cooking process. When cooked, there was a problem of uneven taste.

  The present invention solves the above-described conventional problems, and provides an induction heating rice cooker that prevents a specific place from concentrating and becoming rich in moisture, eliminates unevenness in taste, and improves rice cooking performance. Objective.

In order to solve the conventional problems, an induction heating rice cooker according to the present invention is arranged to face a main body, a pan detachably accommodated in the main body, and a bottom surface of the pan, and heat the pan. A substantially planar annular heating coil for generating an induction magnetic field, an inverter for applying a high-frequency current to the heating coil, and a control means for controlling the inverter for applying a high-frequency current to the heating coil. Has a pan body using a high heat conductive material, and an annular magnetic plate using a magnetic metal material joined to the bottom surface of the pan body to face the heating coil , the magnetic plate and the pan body The magnetic plate at the bottom surface of the bottom plate has a substantially flat surface, and the inner peripheral portion of the bottom surface of the pan body that is not opposed to the heating coil protrudes toward the inner surface inside the inner diameter of the magnetic plate. Shape and It is obtained by so that configuration.

  The induction heating rice cooker of the present invention has a path in which the locally concentrated boiling bubbles move along the convex shape of the bottom surface of the pan body, and therefore, is generated at the upper part of the pan near the inner periphery of the heating coil. Boiling bubbles disperse in a path that rises upward from the location where it occurs and a path that moves along the convex shape of the bottom of the pan body, preventing a specific location from concentrating and becoming moist. It becomes possible, the unevenness of the taste is eliminated, and the rice cooking performance can be improved.

Side sectional view of induction heating rice cooker in Embodiment 1 of the present invention. The principal part sectional side view which shows the principal part of the induction heating rice cooker in Embodiment 1 of this invention. Side sectional view which represents typically the inside of the pan at the time of induction heating of the induction heating rice cooker in Embodiment 1 of this invention. The schematic diagram which shows the stress by the expansion | swelling at the time of induction heating of the pot which comprised the convex shape of the induction heating rice cooker in Embodiment 1 of this invention outside the internal diameter of the magnetic plate. The schematic diagram which shows the stress by the expansion | swelling at the time of induction heating of the pot which comprised the convex shape of the induction heating rice cooker in Embodiment 1 of this invention inside the internal diameter of the magnetic board. Side sectional view schematically showing the inside of a pan during induction heating in a conventional induction heating rice cooker

An induction heating rice cooker according to a first aspect of the present invention is a substantially flat surface that generates an induction magnetic field that is disposed to face a bottom surface of the main body, a pan that is detachably accommodated in the main body, and that heats the pan. An annular heating coil having a shape, an inverter for applying a high-frequency current to the heating coil, and a control means for controlling the inverter for applying a high-frequency current to the heating coil, wherein the pan uses a high heat conductive material. A pan body, and an annular magnetic plate using a magnetic metal material joined to the bottom surface of the pan body so as to face the heating coil, and joins the magnetic plate and the magnetic plate on the bottom surface of the pan body The joining portion to be made is a substantially flat surface, and the inner peripheral portion of the bottom surface of the pan body that is not opposed to the heating coil is configured to be convex toward the inner surface inside the inner diameter of the magnetic plate. is there.

  This creates a path for locally concentrated boiling bubbles to move along the convex shape of the bottom of the pan body, so that the boiling bubbles generated immediately above the inner circumference of the heating coil of the pan Dispersed in a path that rises upward and a path that moves along the convex shape of the bottom of the pan body, it is possible to prevent a specific location from concentrating and becoming too much moisture, eliminating uneven taste , Rice cooking performance can be improved.

Moreover, even if a pan is heated by this, it becomes difficult to peel off a joining of a magnetic board and a pan main body, and it becomes possible to prevent the rice cooking performance of an induction heating rice cooker from falling.

  That is, since the pan body and the magnetic material are different from each other, the coefficients of thermal expansion are different. Therefore, when the pan is heated or cooled, stresses having different sizes are applied to the pan body and the magnetic material due to the difference in thermal expansion coefficient. Therefore, when it has constituted so that the joined part which joins a magnetic board and the magnetic board of the bottom of a pan body may be uneven, joining will become easy to peel off. When the bond is peeled off, the magnetic plate is heated by induction heating, but it becomes difficult for the heat to be conducted to the pan body and the rice cooking performance of the induction heating rice cooker is reduced. However, since the magnetic plate is configured to have a substantially planar shape, stress in a direction in which the magnetic plate is easily peeled does not occur, so that the magnetic plate and the pan body are hardly peeled off.

In addition, because of this, the boiling bubbles generated immediately above the inner periphery of the heating coil of the pan are dispersed in a path rising upward from the generation point and a path moving along the convex shape of the bottom surface of the pan body. It is possible to prevent a specific place from concentrating and becoming a state of much moisture, eliminating unevenness in taste and improving rice cooking performance.

  In addition, it is possible to easily configure the joining portion for joining the magnetic plate and the magnetic plate on the bottom surface of the pan body in a substantially flat shape, and even if the pan is heated or cooled, the joining of the magnetic plate and the pan body is difficult to peel off. It can prevent the rice cooking performance of the induction heating rice cooker from deteriorating.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

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

  In FIG. 1, the main body 1 of the induction heating rice cooker is formed in a substantially cylindrical shape whose upper surface is open, and is provided with a protective frame 10 that is a pot storage portion inside the main body 1. A pan 2 having a water level line drawn on the peripheral surface is detachably disposed. The protective frame 10 is provided so as to enclose the pot 2.

  The heating coil 5 is disposed to face the bottom surface of the pan 2 with the protective frame 10 interposed therebetween, and is configured in a substantially planar 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.

  Moreover, the control means 8 controls the inverter 7 and heats the pan 2 by applying a high frequency current to the heating coil 5.

  A lid 3 is attached to the upper part of the main body 1 so as to be freely opened and closed. The lid 3 is rotatably supported on the rear portion of the protective frame 10 via a hinge 3a and is urged by a rotating spring. The other end of the lid 3 is provided with a hook button (not shown) pivotally supported in front of the protective frame 10 to prevent the lid 3 from being opened. When the hook button is fitted to the lid 3, the lid 3 is held by the hook button without opening and is in a closed state.

  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 portion of the lid 3, and the upper portion communicates with the outside of the main body through a steam tube port 11a. A cylindrical steam cylinder 11 is provided.

  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. Further, 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 rice cooking and heat insulation is steamed. It prevents outflow from outside except 4b.

  The pan temperature detection means 9 can detect the temperature of the pan 2 by heat conduction in contact with the substantially central portion of the bottom of the pan 2. The lid temperature detection means 12 can contact the lid 3 and detect the temperature of the pan 2 by heat conduction.

  The operation display unit 13 receives an operation from the user and notifies the user of the state of the rice cooker.

  A resin case is provided for the main body 1, the lid 3, and the steam cylinder 11, a metal lid is provided for the inner lid 4, a rubber packing is provided for the inner lid packing 4 a and the steam port packing 6, and a litz wire is provided for the heating coil 5. The inverter 7 is a high-frequency inverter, the control means 8 is a microcomputer, the pan temperature detection means 9 and the lid temperature detection means 12 are thermistors, the protective frame 10 is aluminum, and the operation display unit 13 is It can be easily configured by using a touch panel.

  FIG. 2 shows a side sectional view of the pan, the heating coil, and the protective frame in the first embodiment of the present invention.

  In FIG. 2, the pan 2 includes a pan body 2a and a magnetic plate 16 joined to the bottom surface of the pan body 2a. In addition, the pan body 2a has a pan body bottom surface inner periphery which is an inner peripheral portion where the heating coil 5 on the bottom surface of the pan body 2a is not opposed to the pan body bottom surface joint portion 2b which is a joining portion as a portion where the magnetic plate 16 is joined. Let the part 2c and a side be a pan main body side 2d. The pot body bottom inner peripheral portion 2c is formed in a convex shape 20 toward the inner surface.

  The pan body 2a can be easily configured by using a high heat conductive material such as aluminum and the magnetic plate 16 using a magnetic metal material such as a stainless steel plate.

  Next, in the induction heating of the induction heating rice cooker according to the first embodiment of the present invention, the situation in the pan will be described below in comparison with the conventional configuration.

  FIG. 6 is a side sectional view schematically showing the inside of a pan during induction heating in a conventional induction heating rice cooker.

  In FIG. 6, the periphery of the pan is composed of a substantially planar heating coil 105, a protective frame 110, a pan body 102 a, and a substantially planar magnetic plate 116. The bottom surface of the pan body 102a has a substantially planar shape.

  In the substantially planar heating coil 105, the induction magnetic field generated by the heating coil 105 is concentrated in the vicinity of the inner periphery 105 a of the heating coil 105, so that the heating is locally strong immediately above the inner periphery 105 a of the heating coil 105. , Boil bubbles are concentrated. When boiling bubbles are generated at a specific location, the boiling bubbles rise upward from the location, but the swollen rice is cooked due to the moisture remaining in that part until the latter half of the rice cooking process. Rises and causes uneven taste.

  FIG. 3 is a side cross-sectional view schematically showing the inside of the pan during induction heating in the first embodiment of the present invention.

  Heating is locally strong immediately above the inner periphery 5a of the heating coil 5 and boiling bubbles are concentrated and generated. The boiling bubbles rise upward from the generation point and the inner periphery of the bottom of the pan body. Since it distributes to the path | route B which moves along the convex shape 20 of 2c, it can prevent that a specific location concentrates and it will be in a state with much moisture.

  Further, the magnetic plate 16 and the pan main body bottom surface joining portion 2b are substantially flat, the heating coil 5 and the magnetic plate 16 are annular, and the convex shape 20 of the pan main body bottom inner peripheral portion 2c is inside the inner diameter of the magnetic plate 16. It is configured as follows.

  FIG. 4 is a schematic diagram showing stress due to expansion during induction heating of a pan in which the convex shape 20 of the induction heating cooker according to the first embodiment of the present invention is configured outside the inner diameter of the magnetic plate 16, and FIG. It is a schematic diagram which shows the stress by the expansion | swelling at the time of induction heating of the pan which comprised the convex shape 20 of the induction heating cooking appliance in the 1st Embodiment of this invention inside the internal diameter of the magnetic board 16. FIG.

  As shown in FIG. 4, when the convex shape 20 is configured outside the inner diameter of the magnetic plate 16, the magnetic plate 16 is configured to have irregularities that match the convex shape 20. In FIG. 4, the magnetic plate 16 is configured to include a flat surface portion 216a and a slope portion 216b. When the pan 2 is induction-heated or cooled after induction heating, a stress F1 due to the expansion of the flat surface portion 216a and a stress F2 due to the expansion of the inclined surface portion 216b are generated. Therefore, in the direction of the combined vector F3 of the stresses F1 and F2 Stress works. Since the stress F3 acts in a direction in which the magnetic plate 216 moves away from the pan body 2a, the bonding between the magnetic plate 216 and the pan body 2a is easily peeled off. The same is true for the expansion of the pan body 2a.

  As shown in FIG. 5, when the convex shape 20 is configured on the inner side of the inner diameter of the magnetic plate 16, the magnetic plate 16 can be configured in a substantially planar shape, so that the pot 2 is induction-heated or cooled after induction heating. Since the magnetic plate 16 has only a flat portion, only the stress F4 due to expansion is generated, and the magnetic plate 16 and the pan body 2a are hardly separated from each other.

  As described above, the induction heating rice cooker according to the present invention can prevent a specific place in the pan from concentrating and becoming a state of moisture, eliminate unevenness in taste, and improve rice cooking performance. It is useful for rice cookers used in general households and restaurants.

DESCRIPTION OF SYMBOLS 1 Main body 2 Pan 2a, 102a Pan main body 2b Pan main body bottom surface joining part 2c Pan main body bottom inner peripheral part 5, 105 Heating coil 7 Inverter 8 Control means 16, 116, 216 Magnetic plate 20 Convex shape

Claims (1)

The body,
A pan that is detachably stored in the main body;
An annular heating coil having a substantially planar shape that is arranged opposite to the bottom surface of the pan and generates an induction magnetic field that heats the pan;
An inverter that applies a high-frequency current to the heating coil;
Control means for controlling the inverter for applying a high-frequency current to the heating coil,
The pan has a pan body using a high heat conductive material, and an annular magnetic plate using a magnetic metal material joined to the bottom surface of the pan body so as to face the heating coil , the magnetic plate and the The joining portion for joining the magnetic plates on the bottom surface of the pan body is substantially flat, and the inner peripheral portion of the bottom surface of the pan body that is not opposed to the heating coil faces the inner surface inside the inner diameter of the magnetic plate. Induction heating rice cooker with a convex shape.