JPH09117374A - Oven for electromagnetic cooking - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce deformation of the bottom of an oven in the case of being heated in using. SOLUTION: A positioning projection 3 is formed in the center of the bottom 2 of an aluminium die-cast oven main body 1 and a 3-layer clad plate 4a is arranged in the outside of the bottom 2. The 3-layer clad plate 4a is a ring body, the projection 3 is fitted in a hollow part 5a so that the 3-layer clad plate 4a is positioned in an appropriate position in the bottom 2 of the oven main body 1, and the clad plate 4a and the bottom 2 are welded in hot solid phase in this state. The 3-layer clad plate 4a is so constituted that an aluminium plate 6a, a stainless steed plate 7a, and an aluminium plate 6b are cladded in this order from the bottom 2 to the outside of the 3-layer clad plate 4a. This stainless steel plate 7a is heated by an electromagnetic induction current. A clad plate composed of an aluminium plate having a slit in its one side and a stainless steel plate is brought in contact with the bottom 2 of the oven main body as a heating element as a substitute for the 3-layer clad plate 4a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container for an electromagnetic cooker in which a ferromagnetic heating element plate is provided on the outer surface of the bottom of a container body, and the contents in the container are heated by the heating element plate. The present invention relates to a container for an electromagnetic cooker having a reduced bottom deformation. Hereinafter, in the present invention, aluminum and aluminum alloys are collectively referred to as aluminum.

[0002]

2. Description of the Related Art In a pan for an electromagnetic cooker, a magnetic material having a large electric resistance is used as a material in order to utilize heat generated by the pan itself due to electromagnetic induction. There has been proposed a pan in which the main body of the pan for an electromagnetic cooker is made of a non-magnetic material such as aluminum and copper, and a heating element plate is pressure-bonded to the central portion of the pan bottom (Shokai Sho 61-
23292 publication). FIG. 7A is a cross-sectional view showing the conventional pan for an electromagnetic cooker, and FIG. 7B is a bottom view showing the pan. As shown in FIG. 7, the bottom 24 made of a non-magnetic metal of the pan body 22 is provided with a recess 24c projecting inside the pan at the center, and along the periphery of the recess 24c,
The heating element plate 26 is pressure bonded. The heating element plate 26 has an annular shape, and the outer diameter thereof is slightly smaller than the outer diameter of the peripheral edge of the bottom portion 24. Also, the heating element plate 2
A step portion 24d is formed on the bottom portion 24 along the inner circumference 26c of No. 6. On the other hand, an edge portion 24 a is formed on the bottom portion 24 along the outer periphery 26 a of the heating element plate 26.
A step 24e is formed on the boundary between the outer circumference 4a and the outer circumference 26a. Further, the heating element plate 26 has a large number of through holes 26b.
Is provided.

The heating plate 26 is made of a ferromagnetic material and receives magnetic flux from the electromagnetic cooker to generate an eddy current and generate heat.
In addition, in a normal electromagnetic cooker, since magnetic flux is generated in an annular shape, the heating element plate 26 has an annular shape with no central portion, as described above, corresponding to the magnetic flux distribution. It has become a thing.

In the pan for the electromagnetic cooker thus constructed, the bottom portion 24 made of non-magnetic metal such as aluminum is used.
Thermal distortion occurs due to the difference between the coefficient of thermal expansion of the heat generating plate 26 and the coefficient of thermal expansion of the heating element plate 26. In the central portion of the bottom portion 24, the heating element plate 26 does not exist and is hollow.
The thermal strain of the central portion of the is absorbed by the step portion 24d of the concave portion 24c. Further, the thermal distortion of the outer edge portion 26a of the heating element plate 26 is absorbed by the step portion 24e. Therefore, the pot body 2
It is possible to prevent the adhesiveness between the heat generating element plate 2 and the heating element plate 26 from deteriorating. Further, since the heating element plate 26 is provided with the through hole 26b, by press-fitting the material of the pan body 22 into the through hole 26b, a mechanical gap is formed between the heating element plate 26b and the through hole 26b. Joining occurs. In this prior art, the heating element plate 26 uses a stainless steel plate defined by JIS SUS430.

[0005]

However, the above-mentioned prior art has the following problems. That is, the bottom portion 24 of the pot body is made of a non-magnetic metal such as aluminum, and the difference between the coefficient of thermal expansion of the bottom portion 24 and the coefficient of thermal expansion of the heating element plate 26 made of stainless steel is large. There is a problem that the bottom portion 24 is warped toward the outside, that is, toward the heating element plate 26 side. When the change in the bottom portion 24 due to this warpage is large, when the temperature sensor on the electromagnetic heater side is fixed to the electromagnetic heater side, the distance between the temperature sensor and the temperature detecting portion of the bottom portion 24 changes greatly. In addition, it is difficult to accurately measure the temperature of the pot, and the temperature control performance of the electromagnetic heater deteriorates.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a container for an electromagnetic cooker in which deformation of the bottom of the container when heated during use is reduced.

[0007]

An electromagnetic cooker container according to the present invention is an electromagnetic cooker container in which a heating element is joined to the outer surface of the bottom of an aluminum or aluminum alloy container body, wherein the heating element is aluminum or an aluminum alloy. It is a clad plate composed of a plate, a ferritic stainless steel plate and another aluminum or aluminum alloy plate.

Another electromagnetic cooker container according to the present invention is an electromagnetic cooker container in which a heating element is joined to the outer surface of the bottom of a container body made of aluminum or aluminum alloy, wherein the heating element is a ferritic stainless steel plate and aluminum or aluminum. It is a clad plate made of an alloy plate, characterized in that slits are formed in the stainless steel plate.

Still another container for an electromagnetic cooker according to the present invention is the container for an electromagnetic cooker in which a heating element is joined to the outer surface of the bottom of a container body made of aluminum or aluminum alloy,
The heating element is a clad plate made of a ferritic stainless steel plate and an aluminum or aluminum alloy plate, and a slit is formed in the aluminum or aluminum alloy plate.

The slits may be provided in concentric circles centered on the center of the bottom. Also,
The slits may be evenly spaced.

[0011]

In the present invention, a clad plate made of aluminum and a ferritic stainless steel plate is used as a heating element. By joining the aluminum plate of the clad plate to the outer surface of the bottom of the container body, a stainless steel plate that generates heat by eddy current can be arranged on the outer surface of the bottom of the container body. In this case, when the heating element arranged at the bottom of the container for the electromagnetic cooker is a clad plate formed of two layers of different metals, when the container is heated, the material of each component of the clad plate is changed. Due to the existence of the difference in the coefficient of thermal expansion, the bimetal phenomenon may cause the clad plate to warp and deform the bottom surface of the container. That is, when an aluminum plate of a clad plate made of a ferritic stainless steel plate and an aluminum plate is joined to the outer surface of the bottom of the aluminum alloy container body, the coefficient of thermal expansion of the stainless steel plate is smaller than that of the aluminum plate. Therefore, when the container is heated, the clad plate warps so as to have a concave surface.

In order to suppress this warpage, in the container for an electromagnetic cooker according to the first aspect, as a clad plate joined to the outer surface of the bottom of the aluminum container body, a ferrite-based material is used between the aluminum plate and another aluminum plate. Using a 3-layer clad plate sandwiched by stainless steel plates,
A layer of clad plates is bonded to the outer surface of the bottom of the aluminum container body. This prevents the clad plate from warping due to the difference in coefficient of thermal expansion between the aluminum plate and the stainless steel plate, and reduces the behavior of the clad plate at the bottom of the container warping in a concave shape.

In the container for an electromagnetic cooker according to a second aspect, a clad plate made of a ferritic stainless steel plate and an aluminum plate is joined to the outer surface of the bottom of the aluminum container body, and a slit is formed in the stainless steel plate. There is. Further, in the container for an electromagnetic cooker according to claim 3, a clad plate made of a ferritic stainless steel plate and an aluminum plate is joined to the outer surface of the bottom of the aluminum container body, and a slit is formed in the aluminum plate. . As described above, by providing the slit in either the stainless steel plate or the aluminum plate of the clad plate, the effect of the bimetal of the clad plate is divided by the slit. Thereby, the behavior of the clad plate at the bottom of the container warping in a concave shape can be reduced.

When the slits are provided at equal intervals, the amount of deformation of each part divided by the slit becomes equal and the variation of each part due to the warp becomes small.

[0015]

Embodiments of the present invention will now be specifically described with reference to the accompanying drawings. First, the first embodiment will be described. FIG. 1 is a sectional view showing a container for an electromagnetic cooker according to a first embodiment of the present invention. As shown in FIG. 1, a projection 3 for positioning is formed in the center of the bottom 2 of the aluminum die-cast container body 1, and a three-layer clad plate 4a is arranged outside the bottom 2. There is. The three-layer clad plate 4a has an annular shape, and the three-layer clad plate 4a is positioned at an appropriate position on the bottom portion 2 of the container body 1 by fitting the above-described convex portion 3 into the hollow portion 5a. The three-layer clad plate 4a is configured by clad with an aluminum plate 6a, a stainless steel plate 7a, and an aluminum plate 6b. The aluminum plate 6a and the container body bottom 2 are hot-solid bonded by pressing the container body bottom 2 and the clad plate 4a at a high temperature of 350 to 500 ° C.

In the container for an electromagnetic cooker thus constructed, a clad plate 4a consisting of three layers is joined to the bottom of the container body 1. Although the stainless steel plate 7a and the aluminum plate 6 (6a, 6b) have large thermal expansion coefficients, the stainless steel plate 7a is
Since it is sandwiched by a and 6b), the warp of the clad plate 4a during use due to the difference in the thermal expansion coefficient is reduced.
Therefore, the change in the distance between the temperature detecting sensor installed inside the central portion of the heater top plate and the bottom portion 2 of the electromagnetic cooker container installed on the heater can be suppressed to be small. Since the temperature of the container can be accurately measured, the temperature adjustment performance becomes good.

FIG. 6 is a sectional view showing a container for an electromagnetic cooker in which a two-layer clad plate 4c is joined to the bottom portion 2 of the container body 1. As shown in FIG. 6, when the aluminum plate 6c of the two-layer clad plate 4b consisting of the aluminum plate 6c and the stainless steel plate 7b is hot-solid bonded to the bottom portion 2 of the container body 1, the thermal expansion of the stainless steel plate 7b is performed. Since the coefficient is smaller than the coefficient of thermal expansion of the aluminum plate 6c, the clad plate 4c of the bottom portion 2 warps in a direction of a concave surface toward the outside of the clad plate 4c during heating. Therefore, the distance between the bottom portion 2 and the heater changes, and the temperature adjustment performance deteriorates.

Next, the second embodiment will be described. FIG.
FIG. 6 is a cross-sectional view showing a container for an electromagnetic cooker according to a second embodiment of the present invention. 3 is a bottom view showing the same container for an electromagnetic cooker, and FIG. 4 is an enlarged sectional view showing a clad plate 4b portion of the AA ′ surface of FIG. As shown in FIG. 2, a positioning projection 3 is formed in the center of the bottom 2 of the aluminum die-cast container body 1, and a clad plate 4b is arranged outside the bottom 2. The clad plate 4b has an annular shape, and by fitting the above-described convex portion 3 into the hollow portion 5c, the clad plate 4b is positioned at an appropriate position on the bottom portion 2 of the container body 1, and the clad plate 4b and the bottom portion 2b. And are solid-phase hot bonded. The clad plate 4b is composed of an aluminum plate 6d and a stainless steel plate 7c, and the aluminum plate 6d is joined to the bottom portion 2. As shown in FIG. 3, slits 8 are concentrically formed on the stainless steel plate 7c of the clad plate 4b at equal intervals. As shown in FIG. 4, the slit 8 divides the stainless steel plate 7c.

Since the slit 8 is formed in the container for an electromagnetic cooker configured as described above, the effect of the bimetal of the clad plate 4b can be divided. Therefore, the clad plate 4b during use due to the difference in thermal expansion coefficient
The warp of the can be reduced. Further, in the present embodiment, since the slits 8 are provided at equal intervals, the deformation amount of each stainless steel plate 7c divided by the slits 8 becomes uniform, and the variation of the warp change of the clad plate 4b becomes small. If this slit 8 is not formed,
The coefficient of thermal expansion of the stainless steel plate 7c is the aluminum plate 6d.
Since the coefficient of thermal expansion is smaller than the coefficient of thermal expansion, the clad plate 4b has a bimetal effect, and the clad plate 4b of the bottom portion 2 is deformed so that the stainless steel plate 7c side is concave. However, in the clad plate 4b in the present embodiment, the effect of the bimetal can be divided by the slit 8, so that
The clad plate 4b of the bottom portion 2 can prevent the stainless steel plate 7c side from warping in a concave shape. Therefore, as in the first embodiment, a temperature detecting sensor is installed inside the central portion of the heater top plate, and when the electromagnetic cooker container is installed on this heater, the bottom 2 and Since the change in the distance from the container can be suppressed to a small level, the temperature of the container can be accurately measured, and the temperature adjustment performance becomes good.

The clad plate 4b may be made of a stainless steel plate or an aluminum plate divided by slits. FIG. 5 is an enlarged sectional view showing a portion of the clad plate 4c in which the slit 8a is provided on the aluminum plate side. As shown in FIG. 5, a slit 8a is provided in the aluminum plate 6e of the clad plate 4c, and a brazing material 9 is laminated on the surface of the aluminum plate 6e opposite to the stainless steel plate 7d. Brazing material 9 is Al
The clad plate, which is an aluminum material such as —Si type and in which the brazing material 9 is laminated, serves as a brazing sheet. When this brazing material 9 is brought into contact with the bottom of the main body, the brazing sheet is superposed on and fixed to the container body 1, and heated in a furnace, the brazing material 9 is melted and the aluminum plate 6e is joined to the container body. Therefore, the aluminum plate 6e is not likely to be deformed at the time of bonding, and the aluminum plate 6e can be bonded to the bottom portion 2 of the container body 1 without the slit 8a disappearing. Since the slit 8a divides the effect of the bimetal, it is possible to prevent the clad plate 4b of the bottom portion 2 from being warped in a concave shape toward the stainless steel plate 7d side.

In any of the above-mentioned embodiments, the container body 1 is made of Al-Si type aluminum alloy (JIS AD).
C1 and JIS ADC12 die cast alloys, etc.), industrial pure aluminum (JIS 1100 etc.) and Al
-Mn-based aluminum (JIS 3003 or the like) can be used. On the other hand, the clad plate 4 (4a, 4
Since the stainless steel plate 7 (7a, 7c, 7d) of b) needs to be a ferromagnetic material, it needs to be a ferritic stainless steel plate. The aluminum plate 6 (6a, 6b, 6d, 6e) of the clad plate 4 (4a, 4b) is made of industrial pure aluminum (JIS 1100 or the like) and Al-M.
N-type aluminum (JIS 3003 or the like) or the like can be used.

Next, the electromagnetic cooker containers of the first embodiment shown in FIG. 1 and the second embodiment shown in FIG.
The result of comparison with the comparative example shown in will be described. First,
Container for electromagnetic cooker of the first embodiment (Embodiment No. 1 to 5)
The results of comparison between Comparative Example and Comparative Examples (Comparative Examples No. 1 to 5) will be described. Example No. 1 is shown in Table 1 below. The material used and the manufacturing conditions of the container for electromagnetic cookers of 1-5 are shown.

[0023]

[Table 1]

Comparative Example No. 1 is shown in Table 2 below. The material of the clad board of 1-5 is shown. In addition, Comparative Example No. In 1 to 5, as shown in FIG. 6, a two-layer clad plate 4d composed of a stainless steel plate 7b and an aluminum plate 6c is used, and the aluminum plate 6c side is hot on the bottom 2 of the aluminum die casting container body 1. Solid-phase bonded. The aluminum die-cast container 1 was manufactured according to Example No. 1 to 5, the diameter of the clad plate 4d and the pressure contact condition between the clad plate 4d and the aluminum die-cast container 1 are shown in Example No. It is the same as that of 1-5.

[0025]

[Table 2]

Example No. 1 and Comparative Example No. Table 1 shows the results of comparing the amount of warpage at the bottom of the container for No. 1 using a heater having an output of 1200 w until the temperature of each container reached 200 ° C. and the temperature of 200 ° C. The amount of warpage was measured as follows. From the outer periphery of the clad plate 4 (4a or 4d), three points on the center side of about 2 mm in the radial direction are selected. In this case, the points are selected so that the angle between the points is 100 ° or more with the center of the bottom of the container as the center. A virtual plane formed by these three points is used as a reference plane, and the distance from this reference plane to the bottom of the container is the amount of warpage. As for the temperature of the container 1, a hole having a diameter of 1 mm and a depth of 3 mm was made on the inner surface of the center of the bottom of the container, and a sheath type thermocouple having a diameter of 1 mm was embedded in this hole. It was measured.

[0027]

[Table 3]

As shown in Table 3 above, Example No. In No. 1, the amount of warpage was −0.5 mm at room temperature and − when heated.
It is 0.9 mm, which is almost unchanged. On the other hand, in Comparative Example No. 1, the warp amount was −0.5 mm at room temperature,
It was -2.3 mm when heated, and the change in the amount of warpage was extremely large.

Next, a temperature detecting sensor is installed inside the central portion of the heater top plate, and each container is placed on this heater.
When the container was heated while controlling the heater so that the temperature was preset by the temperature detection sensor and the temperature of the container became stable, the set temperature and the temperature of the container were compared (Example No. 2). ˜5, Comparative Examples Nos. 2 to 5). The temperature of the container was measured by embedding a thermocouple in the bottom of the container as described above. The results are shown in Table 4 below.

[0030]

[Table 4]

As shown in Table 4 above, when the examples having the same set temperature and the comparative example are compared, the temperature difference between the respective examples is about half that of the corresponding comparative example. The temperature control performance is good in each of the examples.

Next, the container for electromagnetic cooker of the second embodiment (Example Nos. 6 to 10) and the comparative example (Comparative examples No. 6 to 1).
The result of comparing 0) will be described. Table 5 below shows Example No. 6 to 10 show materials to be used for electromagnetic cooker containers and manufacturing conditions.

[0033]

[Table 5]

The stainless steel plate 7 of the clad plate 4b
c is a circumferential slit 8 with a pitch of 10 mm in the radial direction from a diameter of 80 mm to a diameter of 180 mm and a width of 1 mm.
Is provided.

Comparative Example No. The materials used and the manufacturing conditions for the electromagnetic cooker containers of Nos. 6 to 10 are described in Example No. It is the same as that of 6-10. However, as shown in FIG. 6, the stainless plate 6c is not provided with a slit. Table 6 below shows Comparative Example No. The material of the clad plate of 6-10 is shown.

[0036]

[Table 6]

Example No. 6 and Comparative Example No. Table 6 shows the results of comparing the amounts of warpage of the bottoms of the containers for No. 6 by using a heater having an output of 1200 w until the temperature of each container reaches 200 ° C. and the temperature of 200 ° C. The method for measuring the amount of warpage is as described in Example No. Same as 1.

[0038]

[Table 7]

As shown in Table 7 above, Example No. In No. 6, the amount of warpage was −0.5 mm at room temperature and − when heated.
It is 1.3 mm, which is almost unchanged. On the other hand, in Comparative Example No. 1, the warp amount was −0.5 mm at room temperature,
It was -2.3 mm when heated, and the change in the amount of warpage was extremely large.

Next, Example No. As in Nos. 2-5, a temperature detecting sensor is installed inside the central part of the heater top plate, each container is placed on this heater, and the heater is set to the temperature preset by the temperature detecting sensor. While controlling
When the container was heated and the temperature of the container became stable, the set temperature and the temperature of the container were compared (Example No. 7 to 10, Comparative Example Nos. 7 to 10). The temperature of the container is, as described above,
A thermocouple was embedded in the bottom of the container for measurement. The results are shown in Table 8 below.

[0041]

[Table 8]

As shown in Table 8 above, when the examples having the same set temperature and the comparative example are compared, the temperature difference between the respective examples becomes smaller than the temperature difference of the corresponding comparative example. ing. That is, each example has a good temperature adjusting performance.

[0043]

As described above, according to the container for an electromagnetic cooker according to the first aspect, between the aluminum or aluminum alloy plate and another aluminum or aluminum alloy plate is provided on the outer surface of the bottom of the container body made of aluminum or aluminum alloy. Since the three layers of clad plates sandwiching the ferritic stainless steel plates are joined to each other, it is possible to prevent the bottom of the container from warping during heating.

Further, according to the container for electromagnetic cooker according to the second aspect, the clad plate made of the ferritic stainless steel plate and the aluminum or aluminum alloy plate is joined to the outer surface of the bottom of the container body made of aluminum or aluminum alloy, Since the stainless steel plate is provided with slits, it is possible to prevent the bottom of the container from warping during heating.

Further, according to the electromagnetic cooker container of the third aspect, the clad plate made of the ferritic stainless steel plate and the aluminum or aluminum alloy plate is joined to the outer surface of the bottom of the container body made of aluminum or aluminum alloy, Since the slits are formed in the aluminum or aluminum alloy plate, the bottom of the container can be prevented from warping during heating.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an electromagnetic cooker container according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing an electromagnetic cooker container according to a second embodiment of the present invention.

FIG. 3 is a bottom view showing the container for the electromagnetic cooker according to the second embodiment of the present invention.

4 is an enlarged cross-sectional view showing a clad plate 4b portion of the AA ′ surface of FIG.

FIG. 5 is an enlarged sectional view showing a clad plate 4c portion when a slit 8a is provided on the aluminum plate side.

FIG. 6 is a cross-sectional view showing a container for an electromagnetic cooker in which a two-layer clad plate 4d is joined to the bottom portion 2 of the container body 1.

7A is a sectional view showing a conventional pan for an electromagnetic cooker, and FIG. 7B is a bottom view showing the pan.

[Explanation of symbols]

 1; container body 2, 24; bottom part 3; convex part 4a; three-layer clad plate 4b, 4c, 4d; clad plate 5; hollow part 6a, 6b, 6c, 6d, 6e; aluminum plate 7a, 7b, 7c, 7d Stainless steel plate 8, 8a; Slit 9; Brazing material 22; Pan body 24a; Edges 24d, 24e; Step 26; Heating element plate 26a; Outer circumference 26b; Through hole 26c; Inner circumference

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B23K 20/00 360 B23K 20/00 360B

Claims (5)

[Claims] 1. A container for an electromagnetic cooker in which a heating element is joined to the outer surface of the bottom of an aluminum or aluminum alloy container body, wherein the heating element is an aluminum or aluminum alloy plate, a ferritic stainless steel plate, and another aluminum or aluminum alloy plate. A container for an electromagnetic cooker, which is a clad plate with. 2. An electromagnetic cooker container in which a heating element is joined to the outer surface of the bottom of a container body made of aluminum or an aluminum alloy, wherein the heating element is a clad plate made of a ferritic stainless steel plate and an aluminum or aluminum alloy plate, A container for an electromagnetic cooker, wherein a slit is formed in the stainless steel plate. 3. A container for an electromagnetic cooker in which a heating element is joined to the outer surface of the bottom of an aluminum or aluminum alloy container body, wherein the heating element is a clad plate made of a ferritic stainless steel plate and an aluminum or aluminum alloy plate, A container for an electromagnetic cooker, wherein a slit is formed in the aluminum or aluminum alloy plate. 4. The container for an electromagnetic cooker according to claim 2, wherein the slits are provided in a concentric circle shape centered on the center of the bottom of the container body. 5. The container for an electromagnetic cooker according to claim 4, wherein the slits are arranged at equal intervals.