JPH0833564A - Cooking container for electromagnetic induction heating - Google Patents

Abstract

PURPOSE:To provide a cooking container for electromagnetic induction heating which enables production easily and at a cost with free selection of a shape and achieves excellence in anticorrosiveness. CONSTITUTION:An electromagnetic induction heating cooking container has a cooking container 10 formed by cast molding with a magnetic metal material 26 joined on a lower external surface of the body 25 of a container comprising aluminum. A coating film 30 has a fluororesin applied and baked on the internal surface of the cooking container 10. The purity of aluminum of the body 25 of the container is 85% or more and the thickness of the coating film 30, 35-150mum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooking container for electromagnetic induction heating used for cooking by heating by electromagnetic induction.

[0002]

2. Description of the Related Art In recent years, there has been provided an electromagnetic induction heating type cooker which uses an induction coil as a heating means and heats a cooking container by electromagnetic induction by the induction coil to cook rice or the like.

A cooking container used in such an electromagnetic induction heating cooker includes a container body made of a non-magnetic metal material,
It has a composite structure with a magnetic metal material bonded to the outer surface of the container body.

[0004] An eddy current is generated in the magnetic metal material by the induction coil, and the heat generated by the magnetic metal material based on the eddy current heats the container body to cook the contents therein.

As the material of the container body, aluminum having excellent heat conductivity is used to efficiently conduct the heat of the magnetic metal material to the entire cooking container, and ferrite stainless steel is used as the magnetic metal material. ing.

Conventionally, a cooking container having such a structure has an aluminum thickness of about 1.0 to 1.6 mm and an aluminum thickness of about 0.4 to 0.6 m.
It is formed by using a clad plate bonded to m 2 ferritic stainless steel as a material and pressing the clad plate into a predetermined container shape.

[0007]

However, since hardness and elongation are different between aluminum and stainless steel, wrinkles occur during press working, resulting in poor appearance. Further, if an attempt is made to prevent the generation of wrinkles, the processed shape is restricted.

[0008] Furthermore, in the means by press working, it is necessary to make the clearance of the working die smaller than the material thickness and work while squeezing, so that several dies having different clearances are prepared, and It is necessary to use differently according to the thickness, so that the manufacturing cost is increased and the cost is high.

The present invention has been made by paying attention to such a point, and an object thereof is an electromagnetic induction heating which can freely select a shape, can be manufactured easily and inexpensively, and has excellent corrosion resistance. It is to provide a cooking container for.

[0010]

According to the present invention, in order to achieve the above object, a cooking container in which a magnetic metal material is joined to a lower outer surface of a container body made of aluminum is formed by casting. A cooking container for electromagnetic induction heating provided with a coating film obtained by applying a fluororesin on the inner surface of a container and firing the container, wherein the purity of the aluminum of the container body is 85% or more and the thickness of the coating film is 35%.
.About.150 .mu.m.

The purity of aluminum in the container body is 8
When it is 5%, the thickness of the coating film is 50 to 150 μm.
m, and when the purity of aluminum is 92%, 35 to
It was 150 μm.

[0012]

By forming the cooking container by casting, it is possible to produce the cooking container easily, efficiently and inexpensively without the occurrence of wrinkles and restrictions on the processing shape as in the case of press working.

By the way, when the purity of aluminum of the container body is reduced, the corrosion resistance is reduced. In a cooking container used for cooking rice, the inner surface of the cooking container is likely to corrode due to the influence of rice bran during heat retention, and special consideration must be given to its corrosion resistance.

In the present invention, the purity of aluminum for molding the container body is set to 85% or more, and the coating film made of the fluororesin is formed on the inner surface thereof. When the purity of aluminum is 85% and the thickness of this coating film is 50 μm or more, practically sufficient corrosion resistance can be obtained. The casting aluminum alloy has a high purity of aluminum of 92%, and promotes corrosion of Cu, Fe,
AC4 according to JIS where Zn content is regulated to 0.2% or less
If the material specified as CH is used, the thickness of the coating film is 35 μm or more, and sufficient corrosion resistance can be obtained.

[0015]

Embodiments of the present invention will be described below.
FIG. 1 shows the structure of an electromagnetic induction heating type cooker configured as a rice cooker. Reference numeral 1 denotes an outer frame, and an inner frame formed in the outer frame 1 by a synthetic resin into a bottomed cylindrical shape. 2 are stored. The inner frame 2 integrally has a flange 3 on the outer periphery of the upper part, and the flange 3 is locked to the opening edge portion of the upper end of the outer frame 1, and the inner frame 2 is supported in the outer frame 1 by this locking. ing.

Induction coils 4 and 5 are attached to the outer bottom surface and the lower portion of the outer surface of the inner frame 2, and the induction coils 4 and 5 are covered with a coil cover 6. An opening 7 is formed in the center of the bottom surface of the inner frame 2, and a pan sensor 8 is attached to the center of the bottom surface of the coil cover 6. The pan sensor 8 is attached to the inner bottom of the inner frame 2 through the opening 7. It is protruding.

Inside the inner frame 2, a cooking container 10 as a cooking rice pot is removably housed. A flange 11 which is bent outward is integrally formed at the opening edge of the upper end of the cooking container 10, and the flange 11 is hooked on the opening edge of the upper end of the inner frame 2, whereby the cooking container 10 is formed.
Are supported in the inner frame 2. And this cooking container 10
A predetermined gap is secured between the outer surface of the and the inner surface of the inner frame 2.

A lid 12 is rotatably mounted on the upper surface of the outer frame 1 via a hinge (not shown).
A lid packing 13 and an inner lid 14 are attached to the lower surface of the cooking container 10, and the opening at the upper end of the cooking container 10 is opened and closed by the inner lid 14.

The inner lid 14 is formed with a plurality of small holes 15 through which steam in the cooking vessel 10 flows out, and the lid 12 is provided with a steam port 16 for discharging the steam to the outside. Further, the lid 12 is provided with a lid heater 17 for heating the lower surface of the lid 12 and a lid sensor 18 for detecting the temperature of the lower surface. Further, a body heater 19 is provided in the middle part of the outer periphery of the inner frame 2.

A control board 20 is provided on the inner bottom of the outer frame 1, and an inverter circuit and the like for supplying a high-frequency current to the induction coils 4 and 5 are provided on the control board 20. A cooling fan 22 driven by a motor 21 is provided on the inner bottom portion of the outer frame 1, and an intake port 23 is formed on the bottom surface of the outer frame 1 so as to face the cooling fan 22.
An exhaust port 24 is formed in the lower part of the side surface of the.

The rotation of the cooling fan 22 causes air outside the outer frame 1 to be sucked into the outer frame 1 from the intake port 23, and this air is blown toward the control board 20. The control board 20 is cooled.

The cooking container 10 is composed of a container body 25 made of a non-magnetic metal material and a magnetic metal material 26 provided in a portion extending from the bottom surface of the container body 25 to the lower side surface.

The magnetic metal material 26 faces the induction coils 4 and 5 provided on the inner frame 2 with a predetermined space, and the pan sensor 8 contacts the central portion of the outer bottom surface of the cooking container 10. The temperature of the cooking container 10 is detected by the pan sensor 8.

At the time of cooking, a high frequency current is supplied to the induction coils 4 and 5 by the inverter circuit of the control board 20, and an alternating magnetic field is generated in the induction coils 4 and 5 by the high frequency current. An eddy current flows through the magnetic metal material 26 to be arranged, and the magnetic metal material 26 generates heat due to Joule heat generated by the eddy current, and the heat is transmitted to the container body 25. The water is heated.

The temperature of the cooking vessel 10 is sequentially detected by the pan sensor 8, and the amount of heating of the cooking vessel 10 is adjusted in accordance with the detected temperature in accordance with a preset control sequence. .

The non-magnetic metal material forming the container body 25 of the cooking container 10 is aluminum, which has good thermal conductivity and is lightweight, and the magnetic metal material 26 is, for example, ferritic stainless steel (SUS430).

The cooking container 10 is manufactured by casting, and the steps of this casting will be described below. In this casting molding, as shown in FIG. 2, a lower mold a and an upper mold b are used. The lower mold a has a concave portion c having a shape corresponding to the outer shape of the cooking container 10, and the upper mold b has a convex portion d having a shape corresponding to the inner shape of the cooking container 10.

First, a ferritic stainless steel plate is pressed, and this is molded into a dish shape corresponding to the portion extending from the outer bottom surface of the cooking container 10 to the lower portion of the side surface, and the magnetic metal material 26 to be joined to the container body 25. And

Next, on the upper surface of the magnetic metal material 26, that is, on the aluminum bonding surface, a bonding layer 26a (sprayed iron or the like) having a thickness of 50 to 150 μm is formed. After that, the magnetic metal material 26 is inserted into the concave portion c of the lower mold a and arranged on the inner bottom portion thereof.

In this state, a predetermined amount of molten aluminum as the material of the container body 25 is poured into the recess c of the lower mold a. Then, the convex portion d of the upper die b is pushed into the concave portion c of the lower die a at a pressure of about 1 t / cm ² or more per projected area to press the molten aluminum, and this pressed state is maintained for a predetermined time.

In this step, the molten aluminum enters the bonding layer 26a and causes an anchor effect, whereby the aluminum and the magnetic metal material 26 are firmly bonded. The aluminum is then solidified and the container body 25
Thus, the cooking container 10 in which the magnetic metal material 26 is integrally joined to the container main body 25 is completed. Then, the magnetic metal material 26 is firmly joined to the container body 25 by the anchor effect, so that it can sufficiently withstand repeated heating and cooling during use of the cooking container 10 and there is no danger of peeling of the magnetic metal material 26. Is obtained.

By the way, if the purity of aluminum in the container body 25 is lowered, the corrosion resistance is lowered. In the cooking container 10 used for cooking rice, the inner surface of the cooking container 10 is likely to corrode due to the influence of rice bran during heat retention, and it is necessary to give special consideration to its corrosion resistance.

The aluminum for casting usually contains 1 Si.
When the content is about 0%, the so-called hot water flow is improved, which is preferable in molding, but lowers the corrosion resistance. Therefore, in the present invention, the purity of the aluminum for molding the container body 25 is set to 85% or more, a fluororesin, for example, PFA resin is applied to the inner surface thereof, and the coating film 30 is baked and baked as shown in FIG. Was formed. As a result of various studies, it has been found that when the purity of aluminum is 85% or more, if the thickness of the coating film 30 is 50 μm or more, practically sufficient corrosion resistance can be obtained.

Aluminum having a purity of 85% is A according to JIS.
It is a general die-casting material defined as DC-12, and the container body 25 is molded using this material, and the coating film 30 made of PFA resin is formed on the inner surface of the container body 50 μm.
If it is formed with a thickness of not less than m and no pinholes, practically sufficient corrosion resistance can be obtained.

Further, in an aluminum alloy for castings, the purity of aluminum is as high as 92%, and Cu which promotes corrosion,
If a material defined as AC4CH in JIS in which the contents of Fe and Zn are regulated to 0.2% or less is used, the coating film 30 has a thickness of 35 μm or more and sufficient corrosion resistance can be obtained.

FIG. 4 shows the relationship between the boundary of the range where sufficient corrosion resistance is obtained, the purity of aluminum, and the film thickness of the coating film 30. As shown in this figure, when the purity of aluminum is 85%, the coating film 30
If the film thickness is 50 μm or more, sufficient corrosion resistance can be obtained.
It is understood that sufficient corrosion resistance can be obtained if the film thickness of 0 is 35 μm or more.

However, in any case, when the thickness of the coating film 30 exceeds 150 μm, the heat insulating property of the coating film 30 becomes high, and when the cooking container 10 is used, water inside the container body 25 and the like. Heat conduction to the contents of the cooking container 10 deteriorates, and it is great when the temperature of the contents in the cooking container 10 is detected by the pan sensor 8, particularly when the induction coils 4 and 5 are turned off. Since an error occurs, the thickness of the coating film 30 is 15
It is set to 0 μm or less.

[0038]

As described above, according to the present invention,
Since the cooking container is formed by casting, it can be easily, efficiently, and inexpensively manufactured without the occurrence of wrinkles and restrictions on the processing shape as in the case of press working. And the purity of aluminum of the container body is 85%
As described above, since a coating film having a thickness of 35 to 150 μm is provided on the inner surface, the corrosion resistance of the inner surface of the container body can be sufficiently maintained.

[Brief description of drawings]

FIG. 1 is a sectional view of an electromagnetic induction heating type cooker using a cooking container according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a mold for manufacturing a cooking container.

FIG. 3 is a cross-sectional view of a cooking container.

FIG. 4 is a graph showing the relationship between the boundary of the range where corrosion resistance is obtained, the purity of aluminum, and the film thickness of the coating film.

[Explanation of symbols]

 10 ... Cooking container 25 ... Container body 26 ... Magnetic metal material 30 ... Coating film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuya Miyake 2570, Gosuda, Kamo City, Niigata Prefecture 1 Toshiba Home Techno Co., Ltd.

Claims (2)

[Claims] Claim: What is claimed is: 1. An electromagnetic wave comprising: a cooking container having a magnetic metal material bonded to the lower outer surface of a container body made of aluminum by casting; and a coating film obtained by coating and baking a fluororesin on the inner surface of the cooking container thus formed. A cooking container for induction heating, wherein the purity of the aluminum of the container body is 85% or more, and the thickness of the coating film is 35 to 150 μm.
Cooking container for electromagnetic induction heating, characterized in that 2. An electromagnetic wave, wherein a cooking container in which a magnetic metal material is joined to the lower outer surface of a container body made of aluminum is formed by casting, and a coating film obtained by coating and baking a fluororesin on the inner surface of the formed cooking container is provided. A cooking container for induction heating, wherein the aluminum of the container body has a purity of 85% or more, and the coating film has a thickness of 50 to 150 μm when the purity of aluminum is 85%. A cooking container for electromagnetic induction heating, which has a thickness of 35 to 150 μm at 92%.