JP4323768B2 - Method for manufacturing container having vacuum part - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a container having a vacuum part, and more specifically, when a vacuum container, which is a bottomed cylindrical material formed by a drawing press process (primary press), is pressed into a required shape (secondary press). It is related with the suitable manufacturing method.
[0002]
[Prior art]
Conventionally, an electromagnetic induction heating container or the like used for an inner pot or the like of an IH rice cooker has been formed of a metal clad material. Recently, as a clad material used for an electromagnetic induction heating container as described above, an electromagnetic It is required to be able to perform induction heating and to have a heat insulating performance capable of maintaining a heating state.
In order to meet such a demand, the present applicant has proposed a clad material having a vacuum part in Japanese Patent Application No. 2002-166127.
[0003]
Specifically, as shown in FIG. 7, the clad material 1 has a peripheral wall when a non-magnetic metal plate 2 and a magnetic metal plate 3 are partially joined via a joining metal layer 4 to form a container shape. A non-joining part 5 not interposing the joining metal layer 4 is provided at a part to be a vacuum part, and the clad material 1 is pressed with a die 6 of a squeeze press die and a press as shown in FIG. As shown in FIG. 8 (B), the clad material 1 is drawn and pressed by lowering the punch 8 to form a container-shaped bottomed cylindrical material.
[0004]
[Problems to be solved by the invention]
However, the bottomed cylindrical material having a vacuum portion on the peripheral wall formed by drawing press (primary press) as described above and having a flange protruding from the peripheral edge of the tip opening is non-magnetic so as to form a vacuum portion on the peripheral wall. Since the non-joining portion 5 is provided between the metal plate 2 and the magnetic metal plate 3, the joining between the non-magnetic metal plate 2 and the magnetic metal plate 3 is likely to be peeled off at both end boundary positions of the non-joining portion 5. There is.
[0005]
On the other hand, the bottomed cylindrical material that has been subjected to the drawing press processing (primary press) is then subjected to press molding (secondary press), which is a process of preparing a predetermined container shape using another upper and lower mold. It is desirable if the press molding process can be effectively used for preventing the joint from peeling.
[0006]
The present invention has been made in view of the above problems, and a bottomed cylindrical material having a vacuum portion on a peripheral wall formed by drawing press processing and having a flange protruding from a peripheral edge of a tip opening is formed into a predetermined shape with an upper and lower mold. When molding as a container, it is an object to prevent peeling of the joint portion of the clad material.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention provides a non-bonded vacuum part in a part of a clad material joined with metal plates, and the clad material is subjected to drawing press processing, and has a vacuum part on a peripheral wall and a peripheral edge of a tip opening. Forming a bottomed cylindrical material with a more protruding flange, and molding the bottomed cylindrical material as a container of a predetermined shape with an upper and lower mold,
The lower mold is provided with a mold part that is fitted into the bottomed cylindrical material in an inverted state, while the upper mold that is pressed down toward the lower mold is provided with the inverted A mold part that is externally fitted to the bottom cylindrical material is recessed, and a step is formed on the mold surface of the mold part that corresponds to one end boundary position between one end of the vacuum part provided on the peripheral wall of the bottomed cylindrical material and the joint part on the bottom wall side. The bottom wall side mold surface is reduced in diameter, and the mold surface between the other end boundary position between the other end of the vacuum portion of the peripheral wall and the joint portion of the flange side peripheral wall and the step is made vertical. ,
When the bottomed cylindrical material is molded by the upper and lower molds, the peripheral wall adjacent to the flange of the bottomed cylindrical material is inwardly pressed to correct the vertically curved portion and correct the other Provided is a method for manufacturing a container having a vacuum part, wherein the joint strength at the end boundary position is increased while the joint strength at the one end boundary position is increased by the step. ing.
[0008]
With the above configuration, a part of the clad material in which the metal plates are bonded to each other is provided with a non-bonded vacuum part by drawing press processing (primary press). The peripheral wall has a vacuum part and the flange protrudes from the peripheral edge of the tip opening. After the bottomed cylindrical material is formed, when the bottomed cylindrical material is press-molded (secondary press) into a predetermined shape with an upper and lower mold, the peripheral wall adjacent to the flange of the bottomed cylindrical material is expanded in diameter. The upper curved die is pressed inward with the upper mold to correct it vertically, and the bottom wall of the bottomed cylindrical material is pushed down toward the lower mold with the upper mold, and the vacuum The rolling effect can be obtained at the other end boundary position of the part, and the joining strength can be increased.
In addition, the one end boundary position of the vacuum part is locally strongly pressed against the lower molding die by the step formed by reducing the diameter of the bottom wall side mold surface of the upper molding die. Bonding strength can be increased.
[0009]
Therefore, the bottomed cylindrical material formed by drawing press can be pressed into a predetermined shape, and at the same time, both ends of the vacuum part can be strongly pressed to improve the bonding strength. In addition, it is possible to reliably prevent the metal plates constituting the clad material from being separated from the boundary of the vacuum part.
[0010]
The flange of the bottomed cylindrical material and the tip of the mold part of the upper mold that molds the peripheral wall are formed of another member made of an HZ alloy material having higher strength than the upper mold , and the peripheral wall having the vacuum part is formed. It is pressing with a strong force radially inward.
[0011]
That is, by using an HZ alloy having high hardness, wear resistance and lubricity at the tip of the upper mold, the upper mold is pressed inward while sliding against the peripheral wall of the bottomed cylindrical material. This operation can be performed smoothly without consuming the upper mold.
[0012]
The radius of the inner peripheral tip of the separate member is a radius of curvature smaller than the radius between the peripheral wall of the bottomed cylindrical material and the flange, and the bottomed cylindrical material of the bottomed cylindrical material is between the flange mounting mold surface of the lower mold It is formed so that a horizontal flange with a radius smaller than the vertical peripheral wall tip protrudes.
[0013]
A gap of about 0.05 to 0.15 mm is provided for mold release between the peripheral wall from the one end boundary position to the peripheral wall tip continuous with the flange and the convex mold surface of the lower mold. .
[0014]
With the above configuration, after the bottomed cylindrical material is pressed against the lower molding die by the upper molding die and press molded, when the molded bottomed cylindrical material is removed upward from the lower molding die, Since a minute gap is set between the peripheral wall of the bottomed cylindrical material and the lower mold, it can be released smoothly, without applying a load to the joint boundary at both ends of the vacuum part, It can prevent peeling.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a bottomed cylindrical material 10 serving as an electromagnetic induction heating container such as an inner pot of an IH jar rice cooker, in which an aluminum plate 11 which is a nonmagnetic metal plate and a stainless steel plate 12 which is a magnetic metal plate are joined. The material is formed into a container shape by drawing press (primary press).
[0016]
First, an outline of a plate-like clad material before being formed into a container shape by drawing press processing will be described.
On the upper surface side of the aluminum plate 11, a colored fluororesin is coated as a base coat 14 with a thickness of 5 to 60 μm (25 μm in this embodiment).
At this time, by providing fine irregularities on the surface of the aluminum plate 11, the fluororesin enters the irregularities on the surface, and the base coat 14 made of non-adhesive fluororesin can be firmly performed.
[0017]
Further, a colorless fluororesin is coated on the surface of the base coat 14 as a top coat 15 with a thickness of 5 to 50 μm (in this embodiment, 25 μm). In addition, as a fluororesin used for the basecoat 14 and the topcoat 15, it is preferable to use polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), etc. excellent in heat resistance.
[0018]
On the lower surface side of the aluminum plate 11, a portion corresponding to the peripheral wall 10b of the bottomed cylindrical member 10 is set as a non-plated portion X, and a copper plating layer 13 serving as a bonding metal layer is provided in the remaining portion.
Similarly, on the upper surface side of the stainless steel plate 12, a portion corresponding to the peripheral wall 10b of the bottomed cylindrical member 10 is set as a non-plated portion X, and a copper plating layer 13 serving as a bonding metal layer is provided in the remaining portion.
[0019]
The aluminum plate 11 and the stainless steel plate 12 are stacked concentrically with the copper plating layer 13 interposed, and hot-pressed (hot uniaxial pressing method) to join each other to form a clad material. Part X is a non-bonded vacuum part 16.
The copper plating 13 provided on the stainless steel plate 12 may be provided on the entire surface.
[0020]
The hot press is performed under reduced pressure or under vacuum under conditions of a temperature of 180 to 600 ° C., a pressure of 200 to 1000 kg / cm ² , and a pressing time of 10 min to 30 h. Thereby, while being able to make a non-joining part into the vacuum part 16, the intervention of the gas molecule to a joining interface can be reduced, and the spreading | diffusion of the metals joined can also be accelerated | stimulated.
[0021]
The nonmagnetic metal plate is not particularly limited as long as it has a good thermal conductivity and becomes a heat transfer layer, and materials such as aluminum, aluminum alloy, and nonmagnetic stainless steel are preferably used. The aluminum plate 1 is used from the viewpoint of good conductivity and workability. The aluminum plate 11 has a thickness of 0.5 to 5.0 mm (in this embodiment, 1.7 mm) from the viewpoint of strength, thermal conductivity, etc., and the thickness of the copper plating layer 13 on the lower surface side is as follows. 1 to 50 μm (10 μm in this embodiment).
[0022]
The magnetic metal plate is not particularly limited as long as an eddy current flows by a high-frequency magnetic field to become a heat generating layer, such as magnetic stainless steel, iron, iron alloy, nickel, nickel alloy, copper, copper alloy, cobalt, cobalt alloy, etc. Although a material is used, in this embodiment, a magnetic stainless steel plate 12 is used. The stainless steel plate 12 has a thickness of 0.1 to 3.0 mm (0.5 mm in this embodiment), and the thickness of the copper plating layer 13 on the upper surface side is 1 to 50 μm (in this embodiment). 10 μm).
The copper plating layer 13 may be replaced with aluminum, nickel or / and silver as a plating material.
[0023]
By drawing and pressing the clad material, an electromagnetic induction heating container having the bottom wall 10a and the peripheral wall 10b shown in FIG. 1 and continuously arranging the vacuum part 16 along the entire circumference of the peripheral wall 10b is obtained. A bottomed cylindrical member 10 is formed. The bottomed cylindrical member 10 has a flange 10d projecting from the peripheral edge of the opening of the front end, and a peripheral wall 10b adjacent to the flange 10d is formed with a diameter-enlarged portion 10c that is curved in an enlarged shape. The boundary on the bottom wall 10a side is defined as one end boundary position A, and the boundary on the flange 10d side is defined as the other end boundary position B.
The radius of curvature R1 of the expanded diameter portion 10c is set to R1 = 5T to 9T (mm) when the thickness of the clad material is T (mm).
[0024]
Next, the bottomed cylindrical material 10 is subjected to a molding process for adjusting it into a predetermined shape by press molding (secondary press).
[0025]
The molding die is composed of an upper molding die 20 and a lower molding die 30 as shown in FIG.
The lower mold 30 is provided with a substantially columnar mold 30 a that is fitted into the inverted bottomed cylindrical member 10, and a flange that protrudes laterally at the lower edge of the mold 30. 30b is provided.
Further, as shown in FIG. 3, the column diameter of the mold part 30 a is large enough to provide a release gap L (mm) between the peripheral wall 10 b of the bottomed cylindrical material 10 to be externally fitted and the mold part 30 a. The range of the gap L is 0.05 to 0.15 mm.
[0026]
The upper mold 20 has an annular tip 22 formed of a separate member made of an HZ alloy having high hardness and excellent wear resistance and lubricity at the lower end of a mold body 21 that is externally fitted to an inverted bottomed cylindrical member 10. It is made continuous and the mold part 23 is recessed inside.
The inner peripheral tip of the tip 22 has a rounded portion 22a that is curved in an enlarged diameter, and the radius of curvature R2 of the rounded portion 22a is increased between the peripheral wall 10b of the bottomed cylindrical member 10 and the flange 10d. It is smaller than the radius of curvature R1 of the diameter portion 10c.
The mold surface corresponding to one end boundary position A of the vacuum part 16 of the bottomed cylindrical member 10 of the mold body 21 is provided with a step 21a to reduce the diameter of the mold surface, and the mold from the step 21a to the rounded portion 22a of the tip 22 is provided. The surface is vertical.
[0027]
As shown in FIG. 2, the bottomed cylindrical material 10 is inverted and externally fitted to the mold part 30 a of the lower mold 30, and the upper mold 20 is pressed down toward the lower mold 30, as shown in FIG. 4. Next, the bottomed cylindrical material 10 that is externally fitted to the mold part 30a of the upper mold 30 is externally fitted and pressed.
Thereby, the curved diameter-expanded portion 10c on the flange 10d side of the peripheral wall 10b of the bottomed cylindrical member 10 is pressed inward by the upper mold 20 to be vertically corrected to adjust the shape into an L-shaped cross section.
[0028]
Further, when the upper mold 20 is lowered toward the lower mold 30, as shown in FIG. 3, the upper mold 20 in which the peripheral wall 10 b of the bottomed cylindrical material 10 descends is moved toward the lower mold 30. Therefore, the rolling effect is obtained, and the bonding strength at the other end boundary position B of the vacuum part 16 can be increased.
At this time, the tip 22 which is heavily loaded in the upper mold 20 is made of an HZ alloy having high hardness, wear resistance and lubricity, so that the press work can be smoothly performed without wear. .
[0029]
Furthermore, a gap L for mold release is set to 0.05 to between the peripheral wall 10b from the one end boundary position A to the tip of the peripheral wall 10b continuous with the flange 10d and the convex mold surface 30a of the lower mold 30. Since about 0.15 mm is provided, the mold can be released smoothly from the molded state as shown in FIG. It is possible to prevent peeling without applying a load to the joining boundary positions A and B at both ends of the portion 16.
[0030]
Further, as shown in FIG. 4, the step 21 a of the upper mold 20 causes the outer surface corresponding to one end boundary position A of the vacuum part 16 of the bottomed cylindrical material 10 to be strongly pressed against the lower mold 30 to form a stepped part 10 e. Therefore, the joining strength at the one end boundary position A of the vacuum part 16 can be increased.
[0031]
Accordingly, the bottomed cylindrical material 10 formed by drawing press (primary press) is pressed into a predetermined shape (secondary press), and at the same time, the boundary positions A and B at both ends of the vacuum part 16 are strongly pressed. Therefore, it is possible to reliably prevent the aluminum plate 11 and the stainless steel plate 12 constituting the clad material from being separated from the boundary positions A and B of the vacuum portion 16 without increasing the number of work steps. be able to.
[0032]
Next, fluorine that has been colored so as to make it easy to see inscriptions such as graduations by subjecting the bottomed cylindrical member 10 'shown in FIG. 5 formed by press molding to a heat treatment at 250 to 300 ° C. for a short time. A step of sintering the resin is performed.
[0033]
Then, since the thermal expansion coefficients of the aluminum plate 11 and the stainless steel plate 12 of the bottomed cylindrical member 10 ′ are different, the aluminum plate 11 and the stainless steel plate 12 are automatically moved in the non-bonded vacuum portion 16 as shown in FIG. As a result, the electromagnetic induction heating container 10 ″ with the vacuum part 16 enlarged is formed.
In other words, the heat treatment combines the enlarged formation of the vacuum layer 16 with the sintering process of the fluororesin for coloring, so that the number of work steps can be reduced and a complicated process such as welding is required. Therefore, the electromagnetic induction heating container 10 ″ having the vacuum part 16 can be obtained very easily and inexpensively.
[0034]
【The invention's effect】
As is clear from the above description, according to the present invention, when a bottomed cylindrical material having a vacuum portion on a peripheral wall formed by drawing press processing is pressed into a predetermined shape with an upper and lower mold, the bottomed cylindrical material is By pressing the upper mold with the lower mold toward the lower mold, a rolling effect can be obtained and the bonding strength at the other end boundary position of the vacuum part can be increased.
In addition, since the one end boundary position of the vacuum part is strongly pressed against the lower mold by the reduced step of the upper mold, the bonding strength at the one end boundary position of the vacuum part can be increased.
Therefore, the bottomed cylindrical material formed by drawing press can be press-formed into a predetermined shape, and at the same time, both ends of the vacuum part can be strongly pressed to improve the bonding strength without increasing the number of work steps. The metal plates can be prevented from peeling from the boundary of the vacuum part.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a bottomed cylindrical material after drawing press working according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing an upper and lower molding die for press molding.
FIG. 3 is an enlarged cross-sectional view of a main part during press molding.
FIG. 4 is a cross-sectional view of a state where an upper mold is squeezed down.
FIG. 5 is a cross-sectional view of a bottomed cylindrical material after press forming.
FIG. 6 is a cross-sectional view of a bottomed cylindrical material after heat treatment.
FIG. 7 is a schematic sectional view of a clad material.
FIGS. 8A and 8B are explanatory views of drawing press processing. FIGS.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Bottomed cylindrical material 10a Bottom wall 10b Perimeter wall 10c Diameter expansion part 10d Flange 11 Aluminum plate (nonmagnetic metal plate)
12 Stainless steel plate (magnetic metal plate)
13 Copper plating layer (metal layer for bonding)
14 Base coat (fluorine resin layer)
15 Top coat (Fluororesin layer)
16 Vacuum part 20 Upper mold 21 Mold body 21a Step 22 Tip 22a Round part 23 Mold part 30 Lower mold 30a Mold part A One end boundary position B The other end boundary position L Clearance X Non-plating part

Claims (4)

A non-bonded vacuum part is provided in a part of the clad material joined with metal plates, and the clad material is drawn by press working, and a bottomed cylindrical material having a vacuum part on the peripheral wall and a flange protruding from the peripheral edge of the tip opening is provided. Forming and molding the bottomed cylindrical material as a container of a predetermined shape with an upper and lower mold,
The lower mold is provided with a mold part that is fitted into the bottomed cylindrical material in an inverted state, while the upper mold that is pressed down toward the lower mold is provided with the inverted A mold part that is externally fitted to the bottom cylindrical material is recessed, and a step is formed on the mold surface of the mold part that corresponds to one end boundary position between one end of the vacuum part provided on the peripheral wall of the bottomed cylindrical material and the joint part on the bottom wall side. The bottom wall side mold surface is reduced in diameter, and the mold surface between the other end boundary position between the other end of the vacuum portion of the peripheral wall and the joint portion of the flange side peripheral wall and the step is made vertical. ,
When the bottomed cylindrical material is molded by the upper and lower molds, the peripheral wall adjacent to the flange of the bottomed cylindrical material is inwardly pressed to correct the vertically curved portion and correct the other The manufacturing method of the container which has a vacuum part characterized by raising the joint strength of the junction parts in the said one end boundary position with the said level | step difference, while raising the joint strength of the junction parts in an end boundary position. The flange of the bottomed cylindrical material and the tip of the mold part of the upper mold that molds the peripheral wall are formed of another member having higher strength than the upper mold , and the peripheral wall having the vacuum part is radially inward. The manufacturing method of the container which has the vacuum part of Claim 1 currently pressed with strong force.   The radius of the inner peripheral tip of the separate member is a radius of curvature smaller than the radius between the peripheral wall of the bottomed cylindrical material and the flange, and the bottomed cylindrical material of the bottomed cylindrical material is between the flange mounting mold surface of the lower mold The manufacturing method of the container which has a vacuum part of Claim 2 currently shape | molded so that the flange of a horizontal direction may protrude from the round | angular side smaller than a perpendicular | vertical peripheral wall front-end | tip.   A gap of about 0.05 to 0.15 mm is provided for mold release between the peripheral wall from the one end boundary position to the peripheral wall tip continuous with the flange and the convex mold surface of the lower mold. The manufacturing method of the container which has a vacuum part of any one of Claims 1 thru | or 3.

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