JP2000208242A - Pan for electromagnetic cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent thermal deformation of the bottom part of a frying pan 1 for an electromagnetic cooker by reducing its weight, and also increase output of an electromagnetic cooker. SOLUTION: A frying pan 1 is composed of a clad sheet of an aluminum plate 6 with a stainless steel plate 7 having a thickness thinner than that of the aluminum plate 6. The stainless steel plate 7 is disposed on the outer layer of the frying pan 1. Three annular molded grooves 9 are formed on an outer layer side bottom face 14 of a bottom part 3 of the frying pan 1, being concentrically formed with a center part C of the bottom face 14. The ratio D/t of the depth D of each annular shaped groove 9 to the plate thickness t of the stainless steel plate 7 is set to a value in the range of 1.0<=D/t<=2.5. Thereby, the absorbing power of thermal deformations is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pot, particularly a frying pan, which can be suitably used for an electromagnetic cooker.

[0002]

2. Description of the Related Art In recent years, an electromagnetic cooker has attracted attention as an electric heating appliance capable of rapid heating. The electromagnetic cooker is a heating method in which the bottom of a pot placed on the electromagnetic cooker is induction-heated by electromagnetic induction, and the pot bottom itself is used as a heater. Therefore, iron or iron alloy is used as the material of the pot. Since the bottom of the electromagnetic cooker pan is rapidly heated, it is likely to be thermally deformed and may bulge downward. In this case, the pot cannot be stably placed on the electromagnetic cooker, so that it becomes difficult to use the pan. Therefore, conventionally, a countermeasure has been taken to prevent a thermal deformation of the pot by forming a plurality of annular cutting grooves concentrically at the bottom of the pot.

[0003]

As described above, since a plurality of annular cutting grooves are formed at the bottom of a conventional electromagnetic cooker pot made of iron or an iron alloy, only the depth of the annular cutting grooves is required. There is a problem that it is necessary to increase the plate thickness and the weight of the pan increases. For this reason, an attempt has been made to reduce the weight of the pan by using a plywood of different metals, for example, a plywood of an aluminum plate and a stainless steel plate as a material for the pan. In this case, if the stainless steel plate of the plywood is arranged on the outer layer side of the pan and the annular cutting groove is formed on the outer layer bottom of the bottom of the pan, the thickness of the stainless steel sheet is reduced by cutting, so the output of the electromagnetic cooker is reduced. Is reduced.

The inventors of the present invention have conducted intensive studies on such problems, and as a result, by forming a plurality of annular forming grooves at an appropriate depth on the bottom of the pot instead of the annular cutting grooves as described later. It has been found that the above problem can be solved, and that not only can the output of the electromagnetic cooker be prevented from lowering, but also the output can be improved.

[0005] The present invention has been completed based on this finding, and an object of the present invention is to prevent thermal deformation of the bottom of a pan,
Another object of the present invention is to provide a light-weight electromagnetic cooker pot capable of improving the output of the electromagnetic cooker.

[0006]

SUMMARY OF THE INVENTION The present invention has a bottom that extends substantially flat, and a side wall that extends substantially perpendicular to the bottom.
In a pan for an electromagnetic cooker placed on an electromagnetic cooker and induction-heated by electromagnetic induction, a non-ferrous metal plate and an iron or iron alloy plate thinner than the non-ferrous metal plate are pressed in layers from a laminated plate. An iron or iron alloy plate is arranged on the outer layer side of the bottom and the side wall, and a plurality of annular forming grooves are formed concentrically around the center of the bottom on the outer layer side bottom of the bottom, The ratio D / t between the depth D of each annular groove and the thickness t of the iron or iron alloy plate is selected to be in a range of 1.0 ≦ D / t ≦ 2.5. It is a pot for a cooker.

According to the present invention, since a plurality of annular forming grooves are formed concentrically at the bottom of the electromagnetic cooker pan,
Thermal deformation of the bottom can be evenly absorbed without bias.
Also, the depth D of each annular forming groove and the thickness t of the iron or iron alloy plate
Since the ratio D / t with respect to is selected within a proper range, the ability to absorb thermal deformation can be improved, and FIGS.
As shown in (1), the amount of thermal deformation at the bottom of the pot can be reduced. Further, as shown in FIGS. 9 and 15 described below, the output of the electromagnetic cooker can be improved.

The non-ferrous metal plate of the present invention is an aluminum plate, and the iron or iron alloy plate is a stainless steel plate.

According to the present invention, since the outer layer of the electromagnetic cooker pan is a stainless steel plate and the inner layer is an aluminum plate, the pan can be reduced in weight. Further, since an aluminum plate having good thermal conductivity is arranged in the inner layer of the pan, the temperature distribution at the bottom of the pan can be made uniform. In addition, since the stainless steel plate is arranged on the outer layer of the pot, the corrosion resistance and heat resistance of the pot can be improved.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a simplified perspective view showing the structure of a pan for an electromagnetic cooker according to a first embodiment of the present invention, and FIG. 2 is a bottom view as viewed from II-II in FIG. FIG.
FIG. 3 is a cross-sectional view taken along the line III-III in FIG. The frying pan 1 as the electromagnetic cooker pan of FIG. 1 is shown with its bottom facing upward for the sake of illustration. The frying pan 1 is heated with the bottom placed on an electromagnetic cooker. The electromagnetic cooker applies a high-frequency alternating current to a heating coil inside the utensil, induces an eddy current in the bottom 3 of the frying pan 1 by electromagnetic induction, and inductively heats the bottom 3 using the Joule heat of the eddy current.

The frying pan 1 according to the present embodiment includes a laminated plate of a non-ferrous metal plate and an iron or iron alloy plate, for example, an aluminum plate 6 which is a non-ferrous metal plate, and an iron or iron alloy thinner than the aluminum plate 6. It is made of a laminated plate with a stainless steel plate 7, which is a plate, and is formed by press working.
The forming of the frying pan 1 is performed by setting the laminated plate in a mold so that the stainless steel plate 7 is on the outer layer side. The laminated plate cleans the joining surface of the aluminum plate 6 and the stainless steel plate 7, overlaps the joining surfaces and cold-rolls, brings both metals close to the vicinity of the interatomic distance, presses them in layers, and further heats them. It is produced by interdiffusion of atoms and metal bonding of both metals.

The frying pan 1 includes a disk-shaped bottom 3 extending substantially flat, a cylindrical side wall 4 extending substantially perpendicularly to the bottom 3, and a handle 5 fixed to the side wall 4. A stainless steel plate 7 is disposed on the outer layer side of the bottom portion 3 and the side wall portion 4 of the frying pan 1, and an aluminum plate 6 is disposed on the inner layer side. A plurality (three in the present embodiment) of annular forming grooves 9 are formed concentrically around the center C of the bottom surface 14 on the outer layer side bottom surface 14 of the bottom 3 of the frying pan 1. The cross-sectional shape of the annular groove 9 is substantially semicircular. The outer diameter and the groove width of the annular molding groove 9 are set to predetermined values. Outer diameter D1, D2, D3 of each annular forming groove 9
Are, for example, 83 mm, 103 mm, and 123 m, respectively.
m, and the groove width W of each annular forming groove 9 is, for example, 3.0 mm. The ratio D / t of the depth D of each annular groove 9 to the thickness t of the stainless steel plate 7 is 1.0 ≦ D / t.
It is selected in the range of ≦ 2.5. The reason for this limitation will be described later.

The thickness of the stainless steel plate 7 forming the outer layer of the frying pan 1 is, for example, 0.4 to 1.0 mm.
The plate thickness of the aluminum plate 6 forming the inner layer of the frying pan 1 is, for example, 1.3 to 2.6 mm. The upper and lower limits of the thickness of the stainless steel plate 7 are limited in this manner for the following reasons.

FIG. 4 is a graph showing the relationship between the thickness of the stainless steel plate 7 forming the outer layer of the frying pan 1 and the output of the electromagnetic cooker, and FIG. 5 is for explaining a method of measuring the output of the electromagnetic cooker 17. FIG. The data shown in FIG.
It is determined using a plurality of frying pans 1 having different thicknesses of the stainless steel plate 7. The plate thicknesses of the plurality of frying pans 1 are all 1.7 mm, and the plate thickness of the stainless steel plate 7 is 0.1 to
1.0 mm. Accordingly, the thickness ratio of the aluminum plate 6 to the stainless steel plate 7 of each frying pan 1 is different. The plurality of frying pans 1 of FIG. 4 do not have the annular forming groove 9 formed therein. The output of the electromagnetic cooker 17 was measured by preparing the plurality of frying pans 1 and the electromagnetic cooker 17 of 1.2 kW, placing the frying pan 1 on the electromagnetic cooker 17 as shown in FIG. Is heated to full output, and the inner bottom surface 1 of the bottom 3 of the frying pan 1 is heated.
This is performed by reading the value of the digital output meter 18 when the temperature of the central portion C at 200 reaches 200 ° C.

FIG. 4 shows that the output of the electromagnetic cooker 17 increases as the thickness of the stainless steel plate 7 increases, and the plate thickness is 0.4 m.
It can be seen that the saturation occurs at m and reaches the maximum value. It is for this reason that the lower limit of the thickness of the stainless steel plate 7 is limited to 0.4 mm as described above. The reason why the upper limit of the thickness of the stainless steel plate 7 is limited to 1.0 mm is that when the thickness exceeds 1.0 mm, not only the output cannot be increased but also the weight increases and the weight is reduced. Is no longer possible.

FIG. 6 is a cross-sectional view showing the state of the three annular grooves 9 during molding, and FIG. 7 is a graph showing the relationship between the groove depth D of the annular grooves and the molding force. Three annular grooves 9
Is formed by press working. The press working is performed using an upper mold 12 and a lower mold 11 having three annular projections 10 as shown in FIG. The thickness configuration of the frying pan 1 used for obtaining the data shown in FIG. 7 is as follows: aluminum plate: 2.0 mm, stainless steel plate:
1.0 mm, and the dimensions of each annular projection 10 of the lower mold 11 are a projection height of 2.0 mm and a projection width of 3.0 mm. The outer diameter of each annular projection 10 is substantially the same as the outer diameter of each annular forming groove 9. The black circles in FIG. 7 are symbols representing data when three annular grooves 9 are formed. Also, in FIG.
Data for forming seven annular forming grooves 25 described later are also shown by black triangles for comparison.

FIG. 7 shows that there is a unique relationship between the groove depth of the annular forming grooves 9 and 25 and the forming force, and the groove depth of the annular forming grooves 9 and 25 increases as the forming force increases. The forming force of the three annular forming grooves 9 and the seven annular forming grooves 2
Comparing with the forming force of No. 5, it can be seen that seven pieces require a larger forming force to obtain the same groove depth than three pieces. FIG. 7 is obtained in advance before forming the annular forming grooves 9 and 25.

To form the three annular forming grooves 9, as shown in FIG. 6, the outer layer bottom surface 14 of the bottom 3 of the frying pan 1 is placed on the lower mold 11 having the annular projections 10, and a flat pressing surface is formed. Is performed by pressing the upper mold 12 having the above-mentioned shape against the inner bottom surface 15 of the bottom 3 of the frying pan 1. As a result, three annular grooves 9 are formed on the outer layer bottom surface 14 of the bottom 3 of the frying pan 1 as shown in FIG. Along with this, fine projections also occur on the inner layer bottom surface 15 of the bottom portion 3 of the frying pan 1, but the fine projections are smoothed by polishing. Adjustment of the groove depth D of the three annular forming grooves 9 is performed by obtaining a forming force for a desired groove depth D based on a relationship between the forming force and the groove depth D as indicated by a black circle in FIG. This is performed by applying the obtained molding force to the upper mold 12.

As described above, the ratio D / t of the groove depth D of each annular groove 9 to the thickness t of the stainless steel plate 7 is 1.0 ≦ D
/T≦2.5. The upper and lower limits of the ratio D / t are limited as described above for the following reasons.

FIG. 8 shows the ratio D / t between the groove depth D of the three annular forming grooves 9 and the thickness t of the stainless steel plate 7 and the ratio of the frying pan 1
FIG. 9 is a graph showing the relationship between the thermal deformation amount and the ratio D / t of the groove depth D of the three annular forming grooves 9 to the plate thickness t of the stainless steel plate 7, and the output of the electromagnetic cooker 17. FIG. 10 is a front view for explaining a method for measuring the amount of thermal deformation of the frying pan 1, and FIG. 11 is a plan view for explaining a method for measuring the amount of thermal deformation of the frying pan 1. It is.

The amount of thermal deformation of the frying pan 1 is measured using a dial depth gauge 20 and a support member 21. The support member 21 is an elongated rod-shaped member having a rectangular cross section, and has a dial depth gauge 20 at a substantially central portion in the longitudinal direction.
I support. The supporting member 21 is a side wall 4 of the frying pan 1.
And forms a one-diameter line of a circle formed by the side wall portion 4. Therefore, the support member 21 exists above the central portion C on the inner layer bottom surface 15 of the bottom 3 of the frying pan 1. As shown in FIG. 10, the dial depth gauge 20 is a gap between the lower surface 21 a of the support member 21 at the center C of the inner layer bottom surface 15 of the bottom 3 of the frying pan 1 and the inner layer bottom surface 15 of the bottom 3 of the frying pan 1 (generally And call it H)). The measurement of the amount of thermal deformation is based on the rolling direction (hereinafter referred to as the L direction) of a laminated plate as a material of the frying pan 1,
This is performed in each of a direction perpendicular to the rolling direction (hereinafter, referred to as a C direction). The amount of thermal deformation was measured at the center C on the inner bottom surface 15 of the bottom 3 of the frying pan 1.
When the temperature reaches 200 ° C (hereinafter referred to as after heating)
And after cooling to room temperature after heating (hereinafter referred to as after cooling).

The measurement of the amount of thermal deformation after heating and cooling in the L direction is performed as follows. (1) As shown in FIG. 11, the support member 21 is placed on the diameter line 23 of the side wall 4 parallel to the L direction. (2) The intervals H before, after heating and after cooling are measured, respectively. Thereafter, the measured intervals are defined as HLO, H
L1 and HL2, respectively. (3) Thermal deformation DL1, DL2 after heating and after cooling
Is calculated based on the following equations (1) and (2). DL1 = HL1-HLO (1) DL2 = HL2-HLO (2)

The amount of thermal deformation after heating and cooling in the C direction is measured by placing the support member 21 on the diameter line 24 of the side wall 4 parallel to the C direction as shown in FIG. This is done in the same way as for the direction. The amounts of thermal deformation DC1 and DC2 after heating and cooling in the C direction are determined by the distance H (hereinafter HC) measured before heating, after heating and after cooling.
O, HC1, and HC2, respectively) are described in (3),
It is obtained by substituting into the equation (4). DC1 = HC1-HCO (3) DC2 = HC2-HCO (4)

Thus, the thermal deformation amounts DL1, DL
2, DC1 and DC2 indicate that the bottom portion 3 of the frying pan 1 is thermally deformed convex downward when the value is positive, and that the bottom portion 3 is thermally deformed convex upward when negative.

The thickness configuration of the frying pan 1 used for obtaining the data shown in FIGS. 8 and 9 is an aluminum plate:
1.3 mm, stainless steel plate: 0.4 mm, and the outer diameter of the frying pan 1 is 246 mm. In addition, the annular molding groove 9
Are groove width: 3.0 mm, groove depth D: 0 to 0.73
mm, outer diameter D1: 83 mm, outer diameter D2: 103 mm, and outer diameter D3: 123 mm. The white circles in FIG. 8 are symbols representing the amount of thermal deformation after the heating, and the black circles are symbols representing the amount of thermal deformation after the cooling. FIG. 8A is a graph showing the relationship between the amount of thermal deformation in the L direction and the ratio D / t,
FIG. 8B is a graph showing the relationship between the amount of thermal deformation in the C direction and the ratio D / t. FIG. 8C is a graph showing the average amount of thermal deformation in the L direction and the C direction and the ratio D / t. 6 is a graph showing a relationship with t. The output of the electromagnetic cooker 17 in FIG. 9 was measured by the measuring method shown in FIG.

FIG. 8 shows that the thermal deformation of the bottom 3 of the frying pan 1 decreases as the ratio D / t increases. This tendency is observed after heating, after cooling, in the L and C directions, and in the L and C directions. It can be seen that the average amounts of thermal deformation are almost the same. When the ratio D / t is equal to or greater than 1.0, in other words, when the groove depth D of the annular formed groove 9 is equal to or greater than the plate thickness t of the stainless steel plate, when the ratio D / t is zero for each thermal deformation amount, And the ratio D / t
It can be seen that even if the value increases, the amounts of thermal deformation are maintained at substantially the same level. This is because as the ratio D / t increases, the ability of the annular groove 9 to absorb thermal deformation improves, and the ratio D / t increases.
This is because when / t is 1.0 or more, the ability to absorb thermal deformation saturates.

From FIG. 9, the output of the electromagnetic cooker 17 increases as the ratio D / t increases, and the output of the electromagnetic cooker 17 exceeds 1.0 kW when the ratio D / t satisfies the condition of the present embodiment is 1.0 or more. It turns out that high output is obtained stably. On the other hand, when D / t is zero, in other words, when the annular molding groove 9 is not formed, the output is 0.9 kW, which is lower than that of the present embodiment. According to the investigation by the present inventors, an annular cutting groove (depth: 1 mm, width: 1 mm, number of pieces: 1, and diameter: 150 m) was placed in a frying pan made of a single stainless steel plate.
The output of the electromagnetic cooker in the case of forming m) is 0.9 kW, which is lower than that of the present embodiment.

As described above, it is for this reason that the lower limit of the ratio D / t is limited to 1.0 or more. The reason why the upper limit of the ratio D / t is limited to 2.5 or less is that even if the ratio D / t exceeds 2.5, the amount of thermal deformation further decreases and the output of the electromagnetic cooker 17 increases. Undesirably, when the ratio D / t exceeds 2.5, the groove depth D of the annular forming groove 9 increases, so that the necessary forming force increases as shown in FIG. It is necessary to convert.

As described above, in this embodiment, three annular forming grooves are formed concentrically around the center C of the bottom surface 14 on the outer layer bottom surface 14 of the bottom 3 of the frying pan 1. The thermal deformation of the bottom 3 of the frying pan 1 can be evenly absorbed without bias. Further, since the ratio D / t is set to a value within an appropriate range, the amount of thermal deformation of the bottom 3 can be reduced, and the output of the electromagnetic cooker 17 can be improved. Therefore, the life of the frying pan 1 can be extended, and the heating time for cooking can be shortened. Further, since a light aluminum plate having good thermal conductivity is disposed on the inner layer side of the frying pan 1, the frying pan 1 can be reduced in weight and the temperature distribution of the bottom 3 of the frying pan 1 can be made uniform. Further, since the stainless steel plate 7 is disposed on the outer layer side of the frying pan 1, the frying pan 1 can be induction-heated by electromagnetic induction, and the corrosion resistance and heat resistance of the frying pan 1 can be improved.

FIG. 12 is a simplified bottom view showing the structure of the bottom 3 of the frying pan 1 according to the second embodiment of the present invention. Since the present embodiment is similar to the first embodiment, the corresponding portions are denoted by the same reference characters, and redundant description will be omitted. It should be noted in the present embodiment that seven annular forming grooves 25 are formed on the outer layer bottom surface 14 of the bottom 3 of the frying pan 1. Each annular groove 25 is formed concentrically with the center C of the outer layer side bottom surface 14 as a center. The outer diameter and groove width of each annular groove 25 are set to predetermined values. Each annular groove 2
5 outer diameters D4, D5, D6, D7, D8, D9, D10
Are, for example, 60 mm, 70 mm, 80 mm,
90 mm, 100 mm, 110 mm, and 120 mm, and the width of each annular formed groove 25 is, for example, 3.0 m.
m.

FIG. 13 is a cross-sectional view showing a state when seven annular forming grooves 25 are formed. To form the seven annular forming grooves 25, as shown in FIG. 13, the outer-layer-side bottom surface 14 of the bottom 3 of the frying pan 1 is placed on a lower mold 27 having seven annular protrusions 26, and a flat pressing surface is formed. Is performed by pressing the upper mold 12 having the above-mentioned shape against the inner bottom surface 15 of the bottom 3 of the frying pan 1. Adjustment of the groove depth D of the annular molding groove 25 is performed by the first
Similarly to the embodiment, the forming force for the desired groove depth D is obtained based on the relationship between the forming force indicated by the black triangle mark and the groove depth D in FIG. 7, and the obtained forming force is increased. This is performed by applying to the mold 12.

In this embodiment, similarly to the first embodiment, the groove depth D of each annular groove 25 and the stainless steel plate 7
The ratio D / t to the plate thickness t is selected in a range of 1.0 ≦ D / t ≦ 2.5. The upper and lower limits of the ratio D / t are limited as described above for the following reasons.

FIG. 14 shows the groove depth D of the seven annular grooves 25.
15 is a graph showing the relationship between the ratio D / t of the thickness of the stainless steel plate 7 to the thickness t of the stainless steel plate 7 and the amount of thermal deformation of the frying pan 1. FIG. 4 is a graph showing the relationship between the ratio D / t of the plate thickness t and the output of the electromagnetic cooker 17. The method of measuring the amount of thermal deformation of the frying pan 1 and the output of the electromagnetic cooker 17 is the same as in the first embodiment.

The thickness configuration of the frying pan 1 used for obtaining the data shown in FIGS. 14 and 15 is as follows: an aluminum plate: 1.3 mm, a stainless steel plate: 0.4 mm,
The outer diameter of the frying pan 1 is 246 mm. The dimensions of each annular groove 25 are as described above.
Has a groove depth D of 0 to 0.56 mm. The white triangles in FIG. 14 are symbols representing the amount of thermal deformation after the heating, and the black triangles are symbols representing the amount of thermal deformation after the cooling. FIG. 14A is a graph showing the relationship between the thermal deformation in the L direction and the ratio D / t, and FIG. 14B is a graph showing the relationship between the thermal deformation in the C direction and the ratio D / t. FIG.
(3) is a graph showing a relationship between the average thermal deformation amount in the L direction and the C direction and the ratio D / t.

From FIG. 14, it can be seen that the thermal deformation of the bottom 3 of the frying pan 1 decreases as the ratio D / t increases. It can be seen that the value is much smaller than when t is zero. Further, in the present embodiment, the correlation between the thermal deformation amount and the ratio D / t is stronger than in the first embodiment, and it can be seen that the thermal deformation amount can be controlled with higher accuracy by the ratio D / t.

As shown in FIG. 15, the output of the electromagnetic cooker 17 increases as the ratio D / t increases, and when the ratio D / t is 1.0 or more, the output of the electromagnetic cooker 17 becomes 1.0 as in the first embodiment. 0
It is understood that a high output of kW or more can be stably obtained. As described above, it is for this reason that the ratio D / t is limited to 1.0 or more. The ratio D / t is 2.5
The reason for being limited to the following is the same as in the case of the first embodiment.

As described above, in the present embodiment, since a large number of annular forming grooves 25 are formed as compared with the first embodiment, the amount of thermal deformation of the frying pan 1 can be made more accurate than in the first embodiment. Can be controlled stably. In addition, the first
The same effect as that of the embodiment can be obtained.

As described above, in the first and second embodiments, the laminated plate as a material of the frying pan 1 is made of a non-ferrous metal plate and an iron or iron alloy plate, and an aluminum plate is used as the non-ferrous metal plate. Although a stainless steel plate is used as the iron or iron alloy plate, the present invention is not limited to this combination, and another non-ferrous metal plate may be used. Further, although the cross-sectional shapes of the annular forming grooves 9 and 25 are formed in a substantially semicircular shape, they may be formed in another cross-sectional shape, for example, a triangular shape.

[0039]

As described above, according to the first aspect of the present invention, the amount of thermal deformation at the bottom of the induction cooker pan can be reduced, and the output of the induction cooker can be improved.
Therefore, the life of the pot for the electromagnetic cooker can be extended, and the heating time for cooking can be shortened.

According to the second aspect of the present invention, since the outer layer of the electromagnetic cooker pan is a stainless steel plate and the inner layer is an aluminum plate, the pan can be reduced in weight.
Further, since the aluminum plate having a good thermal conductivity is arranged in the inner layer of the pan, the temperature distribution at the bottom of the pan can be made uniform. Further, since the stainless steel plate is disposed on the outer layer of the pot, the corrosion resistance and heat resistance of the pot can be improved.

[Brief description of the drawings]

FIG. 1 is a simplified perspective view showing the configuration of a pot for an electromagnetic cooker according to a first embodiment of the present invention.

FIG. 2 is a bottom view as viewed from II-II in FIG.

FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a graph showing the relationship between the thickness of the stainless steel plate 7 forming the outer layer of the frying pan 1 and the output of the electromagnetic cooker.

FIG. 5 is a plan view for explaining a method of measuring the output of the electromagnetic cooker 17.

FIG. 6 is a cross-sectional view showing a state when three annular forming grooves 9 are formed.

FIG. 7 is a graph showing a relationship between a groove depth D of an annular forming groove 9 and a forming force.

FIG. 8 is a graph showing a relationship between a ratio D / t of a groove depth D of three annular forming grooves 9 to a thickness t of the stainless steel plate 7 and an amount of thermal deformation of the frying pan 1.

9 is a graph showing the relationship between the ratio D / t of the groove depth D of the three annular forming grooves 9 and the thickness t of the stainless steel plate 7 and the output of the electromagnetic cooker 17. FIG.

FIG. 10 is a front view for explaining a method of measuring a thermal deformation amount of the frying pan 1.

FIG. 11 is a plan view for explaining a method of measuring a thermal deformation amount of the frying pan 1.

FIG. 12 is a bottom view showing a simplified configuration of a bottom portion 3 of the frying pan 1 according to the second embodiment of the present invention.

FIG. 13 is a cross-sectional view showing a state at the time of forming seven annular forming grooves 25.

FIG. 14 is a graph showing the relationship between the ratio D / t of the groove depth D of the seven annular forming grooves 25 to the thickness t of the stainless steel plate 7 and the amount of thermal deformation of the frying pan 1.

FIG. 15 is a graph showing the relationship between the ratio D / t of the groove depth D of the seven annular forming grooves 25 to the plate thickness t of the stainless steel plate 7 and the output of the electromagnetic cooker 17;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Frying pan 3 Bottom part 9, 25 Annular forming groove 10, 26 Annular protrusion 11, 27 Lower mold 14 Outer side bottom surface 15 Inner side bottom surface 17 Electromagnetic cooker

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Tatsuhiro Den, 1 Tsurumachi, Amagasaki-shi, Hyogo F-term in Nisshin Steel Co., Ltd. Technical Research Laboratory (reference) 3K051 AB05 AC53 AD05 AD07 AD32 AD34 AD38 CD42 CD43 CD44 CD45

Claims (2)

[Claims] 1. A pan for an electromagnetic cooker which has a substantially flat bottom portion and a side wall portion which extends substantially perpendicularly to the bottom portion, is placed on the electromagnetic cooker, and is induction-heated by electromagnetic induction. An iron or iron alloy plate, which is thinner than a non-ferrous metal plate, is composed of a laminated plate that is pressure-bonded in layers. An iron or iron alloy plate is arranged on the outer layer side of the bottom and side walls, and the outer layer on the bottom On the bottom surface, a plurality of annular forming grooves are formed concentrically around the center of the bottom surface, and the depth D of each annular forming groove and the thickness t of the iron or iron alloy plate are set.
Wherein the ratio D / t with respect to is selected to be in the range of 1.0 ≦ D / t ≦ 2.5. 2. The pot according to claim 1, wherein the non-ferrous metal plate is an aluminum plate, and the iron or iron alloy plate is a stainless steel plate.