JP2002078604A - Pot for rice cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pot for a rice cooker that produces a good thermal convection. SOLUTION: The electromagnetic induction heating section of a pot for a rice cooker cooking rice by electromagnetic induction heating is made up of a magnetic metal layer 13 and a nonmagnetic metal layer 11 thinner than the magnetic metal layer as the outer layer, and a good convection is maintained by controlling magnetic force density by providing a nonmagnetic metal layer covering portion 10 in the site opposite to a heat induction coil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic induction heating type rice cooker used for ordinary households and businesses.

[0002]

2. Description of the Related Art At present, an electromagnetic induction heating type rice cooker which is widely marketed in the general public has a magnetic field line generated when a high-frequency current is applied to a heating induction coil provided inside a main body. When entering the magnetic metal capable of induction heating, an eddy current is generated in the magnetic metal, and the pot generates heat as electric resistance of the eddy current, and this heat is applied to cooking rice.

[0003] Conventionally, a typical cooker for induction heating type rice cookers has an inner surface covered with a fluororesin coating, a lower layer of aluminum having good heat conductivity, and an outer surface, that is, an outermost surface of the pan. Is ferritic stainless steel,
A magnetic metal layer made of iron, permalloy, or the like is provided, and the magnetic metal layer serves as a heat generating portion for electromagnetic induction heating.

[0004]

Cooking rice is a process in which rice and water are put into a pot of a rice cooker and cooked by heating. The result of cooking rice is how uniform rice is produced through this process. It depends on whether you can heat it.

[0005] In this respect, the electromagnetic induction heating type rice cooker employs a conventional heater system, that is, an indirect heating system in which a heater is arranged under a pan to heat the heater, and the heat heats the pan. The heat power is larger than that of cooked rice cookers, and heat convection has been improved by devising the electromagnetic induction heating coil into two parts, an inner coil and an outer coil.

[0006] However, in order to obtain better rice cooking results, more varied and finer heat convection must be caused to achieve more uniform heating.

In the case of a conventional electromagnetic induction heating type rice cooker, the portion of the pot facing the heating induction coil is heated to cause convection.
The heating cannot produce uniform and variable convection.

[0008] The present invention has been made in view of the above circumstances, and by changing the magnetic flux density of the heating induction coil facing portion of the pot partially intentionally and controlling the heating in the portion, more ideal. This is to obtain convection.

[0009]

In order to solve the above-mentioned problems, the present invention provides a magnetic metal layer and a non-magnetic metal layer thinner than the magnetic metal layer on its outer layer, and a partial layer is formed on a portion facing the induction heating coil. In which a non-magnetic metal layer non-covered portion or a portion having a thickness of the non-magnetic metal layer which is １ ／ or less of other portions is provided.

[0010]

According to the first aspect of the present invention, a magnetic metal layer and a non-magnetic metal layer thinner than the magnetic metal layer are provided on an outer layer of the magnetic metal layer, and a non-magnetic metal layer is partially provided at a portion facing the induction heating coil. An uncoated portion, or a portion provided with a thickness of the non-magnetic metal layer that is equal to or less than の of other portions, and the non-magnetic metal is aluminum, copper, titanium, or
An alloy metal such as brass can be used. These non-magnetic metals are usually non-magnetic materials, and the lines of magnetic force emitted from the electromagnetic induction heating coil tend to concentrate on the non-magnetic material non-coating portion avoiding the non-magnetic material. For this reason, the density of the magnetic field lines is different between the non-magnetic material-free portion or the thin portion and the non-magnetic material-coated portion, and the portion where the magnetic field lines are concentrated generates strong heat, and the portion where the magnetic field lines are not concentrated generates relatively weak heat, As a result, a difference occurs in the partial heat generation, and it is possible to cause a change in the heat convection.

[0011] In addition, the nonmagnetic metal requires some contrivance for heating by electromagnetic induction. However, as the thickness of the nonmagnetic metal is reduced, the skin resistance increases, and eventually the electromagnetic induction heating becomes possible. In addition, induction heating can be sufficiently performed.

The rice cooker according to the second aspect is characterized in that the nonmagnetic metal layer of the electromagnetic induction heating portion is formed by plating, and has an advantage that the thickness can be changed relatively freely. In addition, it is relatively easy to partially change the thickness.

[0013] The rice cooker according to claim 3 is characterized in that the non-magnetic metal of the electromagnetic induction heating portion is subjected to an anodic oxide film treatment or a protective coating treatment or both. When the metal layer is aluminum or titanium, various colors can be obtained by various anodic oxidations. In the case of titanium, the same color can be obtained by high-temperature oxidation. In addition, it is possible to produce a unique metallic color such as copper or an alloy thereof.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment utilizing the present invention will be described.
This will be described with reference to FIGS. 1, 2 and 3.

FIG. 1 shows a rice cooker of a type in which a pot 9 is heated and cooked by electromagnetic induction heating. An electromagnetic induction heating coil 1, a ferrite 2, a pan bottom temperature detecting sensor 3, a heating control board 4, a board cooling fan 5, an operation. The part 6, the heating plate 7, the steam cap 8, and the pot 9 are the main components, and rice and water are added to the pot in an appropriate amount, and then the rice cooking and warming steps are performed. Is executed by

The pan 9 is made of 1 mm thick aluminum and 0.5
After pressing a clad material made of ferritic stainless steel having a thickness of 0.1 mm, the outer surface of the ferritic stainless steel is subjected to a nickel strike plating of 0.1 μm thickness as a base treatment, and a nonmagnetic metal layer having a thickness of 5 μm is formed on the outer surface.
It is obtained by copper plating of μm, and ferritic stainless steel and copper are heating layers for electromagnetic induction heating.

In this embodiment, the material of the magnetic metal layer of the pot is
Although ferritic stainless steel was used, the material is not limited to this, and any material can be used as long as it is a magnetic metal material that can be electromagnetically induced.

Here, as shown in FIG. 2, a portion of the pot 9 opposed to the electromagnetic induction heating coil is provided with a plurality of copper-plated non-coated portions having a diameter of 5 mm, that is, a plurality of non-magnetic metal layer non-coated portions 10. However, when the pot is subjected to the copper plating process, masking is performed in advance so that the pot is not covered with the copper plating. As another method, a method of removing copper plating at a predetermined portion by an electrolytic treatment using an acid such as nitric acid or an electrolytic solution after the copper plating treatment, or a method of mechanically removing a part of the copper plating can be used.

The shape and area of the non-magnetic layer non-coating portion 10 are arbitrary, and can be freely designed so as to generate a desired heat convection.

In this embodiment, a high-frequency current of 25 kHz flows through the electromagnetic induction heating coil during rice cooking. At this time, lines of magnetic force generated by the induction coil pass through the copper and ferritic stainless steel layers, which are induction heating portions of the pot. At this time, an eddy current is generated, and the pot generates heat. This heat causes the rice cooking process to be performed and the rice to be cooked.

In this embodiment, a high-frequency current of 25 kHz is used. However, it is optional to change this frequency depending on the situation, and it is also optional to change the thickness of the base material accordingly.

Further, in the pot for the electromagnetic induction heating type rice cooker of this embodiment, the outer layer of the electromagnetic induction heating portion is made of copper, and the outer surface of the copper is made of a silicone-based clear material in consideration of being easily damaged and discolored. Painted to maintain high durability while maintaining the beautiful base color of copper.

FIG. 3 schematically shows the state of heat generation in the pot for an electromagnetic induction heating type rice cooker of the present invention, as shown in FIG. 3, in which the lines of magnetic force are concentrated on the non-magnetic metal layer non-coating portion 10, where strong heat is generated. In addition, the lines of magnetic force do not concentrate on the nonmagnetic metal layer coating portion 11, and the heat generation is relatively weak. By intentionally providing a portion where the lines of magnetic force are concentrated and a portion where the lines of magnetic force are not concentrated, a more varied thermal convection is caused and the convection can be controlled.

FIG. 4 shows a heating state of a conventional product made of aluminum 12 and ferritic stainless steel 13, but since the heating induction coil opposing portion is heated relatively uniformly, thermal convection cannot be controlled.

[0025]

As described above, according to the present invention, good heat generation and convection can be obtained by using a magnetic metal and a non-magnetic metal in the electromagnetic induction heating section and partially providing the non-magnetic metal non-coating section. It is possible to provide an electromagnetic induction heating type rice cooker pan with a beautiful appearance utilizing a metal material color.

[Brief description of the drawings]

FIG. 1 is a sectional view of a rice cooker using a rice cooker pot according to one embodiment of the present invention.

FIG. 2 is a bottom plan view of the pot.

FIG. 3 is an explanatory view showing a magnetic force concentration state of the pot.

FIG. 4 is a sectional view of a conventional pot.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electromagnetic heating induction coil 2 Ferrite 3 Bottom and bottom temperature detection sensor 4 Heating control board 5 Substrate cooling fan 6 Operation part 7 Heating plate 8 Steam cap 9 Pan 10 Non-magnetic metal layer non-coating part 11 Non-magnetic metal layer coating part 12 Aluminum 13 Ferritic stainless steel

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4B055 AA03 BA57 BA63 CA02 CA04 CA05 DA02 DB14 FA02 FA03 FB01 FB02 FB03 FB05 FB06 FC06 FC20 FD10 FE02

Claims (3)

[Claims] 1. A magnetic metal layer and a non-magnetic metal layer thinner than the magnetic metal layer provided on an outer layer of the magnetic metal layer. A cooker pot provided with a non-magnetic metal layer having a thickness of 1/2 or less. 2. The rice cooker pot according to claim 1, wherein the non-magnetic metal layer of the electromagnetic induction heating portion is formed by plating. 3. Anodizing film treatment or protective coating treatment on the surface of the non-magnetic metal layer of the electromagnetic induction heating portion.
Or both of them are applied.
Or the pot for rice cookers according to 2.