JP2004122154A - Method for manufacturing vessel having vacuum part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a joined part from being separated when a bottomed cylindrical vessel having a vacuum part on the peripheral wall is formed by pressing. <P>SOLUTION: A die part 30a for fitting to the inner part of the bottomed cylindrical vessel 10 is projectingly provided on a lower forming die 30 and on the other side, a die part 23 for fitting to the outer part of this vessel 10 is recessively provided on an upper forming die 20. Then, a step-difference 21a for reducing the diameter is arranged at the die part 23 corresponding to a boundary position A at the one end of the vacuum part 16 on the peripheral wall 10b of this vessel 10 and the one end of the joined part 13 at the bottom wall 10a and also, a die surface is set to be perpendicular between the boundary position A at the other end of the vacuum part 16 on the peripheral wall 10b and the other end of the joined part 13 at a flange 10d side and the step-difference 21a. When this vessel 10 is formed with the both dies 20, 30, a portion 10c curving as expanded diameter state on the peripheral wall 10b adjecent to the flange 10d is pressed toward the inner part and corrected to the vertical state and also, the joined strength of the joined part 13 at the other end boundary position B is improved and on the other side, the joined strength of the joined part 13 at the one end boundary position A is improved with the step-difference 21a. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a container having a vacuum portion, and more particularly, to press-forming (secondary press) a vacuum container which is a bottomed cylindrical material formed by drawing press processing (primary press) into a required shape. The present invention relates to a preferred production method of
[0002]
[Prior art]
Conventionally, an electromagnetic induction heating container or the like used for an inner pot of an IH rice cooker or the like is formed of a metal clad material. It is required to have both induction heating and heat insulation 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 portion in Japanese Patent Application No. 2002-166127.
[0003]
More specifically, as shown in FIG. 7, the clad material 1 is formed by partially joining the non-magnetic metal plate 2 and the magnetic metal plate 3 via the joining metal layer 4 to form a peripheral wall in a container shape. A non-joining portion 5 without the joining metal layer 4 is provided at a portion to be a vacuum portion, and as shown in FIG. 8 (A), the clad material 1 is pressed against a die 6 of a drawing press die. 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, as described above, a cylindrical material with a bottom provided with a vacuum portion on the peripheral wall formed by drawing press processing (primary press) and having a flange protruding from the peripheral edge of the opening at the front end is non-magnetic in order to form a vacuum portion on the peripheral wall. Since the non-joined portion 5 is provided between the metal plate 2 and the magnetic metal plate 3, the joint between the non-magnetic metal plate 2 and the magnetic metal plate 3 may be easily separated at the boundary between both ends of the non-joined portion 5. There is.
[0005]
On the other hand, the above-mentioned bottomed cylindrical material subjected to the drawing press working (primary press) is thereafter subjected to press forming (secondary press), which is a step of preparing a predetermined container shape using another upper and lower forming die. It is desirable that the press forming process can be effectively used to prevent the peeling of the joint.
[0006]
The present invention has been made in view of the above problems, and provides a bottomed cylindrical material having a vacuum portion on a peripheral wall formed by drawing press working and having a flange protruding from a peripheral edge of a front end opening in a predetermined shape by a vertical molding die. An object of the present invention is to prevent separation of a joining portion of a clad material when forming a container.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention provides a non-joined vacuum part in a part of a clad material in which metal plates are joined together, and draws and presses the clad material to provide a vacuum part on a peripheral wall and a peripheral edge of a tip opening. A method of forming a bottomed cylindrical material from which a flange is more protruding, and molding the bottomed cylindrical material as a container having a predetermined shape with a vertical molding die,
The lower molding die has a protruding mold portion that is to be fitted into the inverted bottomed cylindrical member, while the inverted molding is pressed down toward the lower molding die. A mold part externally fitted to the bottom cylindrical material is recessed, and a step is formed on a mold surface of the mold part which is located at one end boundary position between one end of a vacuum part provided on the peripheral wall of the bottomed cylindrical material and a joint part on the bottom wall side. The bottom wall side mold surface is provided to reduce the 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 joining portion of the flange side peripheral wall and the step is vertical. ,
When forming the bottomed cylindrical material with the upper and lower forming dies, the peripheral wall adjacent to the flange of the bottomed cylindrical material presses inward the portion where the diameter is curved so as to be inwardly straightened, and the other portions are vertically corrected. Provided is a method for manufacturing a container having a vacuum portion, wherein the joining strength between the joined portions at the end boundary position is increased while the joining strength between the joined portions at the one end boundary position is increased by the step. ing.
[0008]
With the above configuration, a part in which a non-bonded vacuum portion is provided in a part of a clad material in which metal plates are bonded to each other is provided with a vacuum portion on a peripheral wall by a squeezing press process (primary press), and a flange protrudes from a peripheral edge of a front end opening. After forming the bottomed cylindrical material, when the bottomed cylindrical material is press-formed (secondary press) into a predetermined shape by a vertical molding die, the peripheral wall adjacent to the flange of the bottomed cylindrical material expands in diameter. The portion curved into a shape is pressed inward by the upper molding die to perform vertical correction, and the peripheral wall of the bottomed cylindrical material is pressed toward the lower molding die by the descending upper molding die, and the vacuum The rolling effect is obtained at the boundary position of the other end of the portion, and the joining strength can be increased.
Further, the step of reducing the diameter of the bottom wall side mold surface of the upper molding die causes the one end boundary position of the vacuum part to be strongly pressed locally against the lower molding die. The joining strength can be increased.
[0009]
Therefore, the bottomed cylindrical material formed by drawing press working can be press-formed into a predetermined shape, and at the same time, the joining strength can be improved by strongly pressing both ends of the vacuum portion, thereby increasing the number of working steps. 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 tip of the mold part of the upper molding die for forming the flange and the peripheral wall of the bottomed cylindrical material is formed of a separate member made of a high-strength HZ alloy material, and the peripheral wall having the vacuum portion is radially inward. Pressing with strong force.
[0011]
That is, by using an HZ alloy having high hardness and abrasion 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. Can be performed smoothly without the consumption of 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 is disposed between the flange mounted surface of the lower forming die. The horizontal flange is formed so as to protrude with a radius smaller than the vertical peripheral wall end.
[0013]
A gap of about 0.05 to 0.15 mm is provided between the peripheral wall between the one end boundary position and the front end of the peripheral wall continuous with the flange and the convex mold surface of the lower molding die for mold release. .
[0014]
With the above configuration, after pressing the bottomed cylindrical material against the lower molding die with the upper molding die and press-molding, when removing the molded bottomed cylindrical material upward from the lower molding die, Since a small gap is set between the peripheral wall with the bottomed cylindrical material and the lower molding die, it is possible to release the mold smoothly, without applying a load to the joining boundaries at both ends of the vacuum part. Peeling can be prevented.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a bottomed cylindrical member 10 serving as an electromagnetic induction heating container such as an inner pot of an IH jar rice cooker, and a clad in which an aluminum plate 11 which is a non-magnetic 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 working (primary press).
[0016]
First, a plate-shaped clad material before being formed into a container shape by drawing press processing will be outlined.
The upper surface of the aluminum plate 11 is coated with a colored fluororesin as the base coat 14 to a thickness of 5 to 60 μm (25 μm in the present 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 a non-adhesive fluororesin can be firmly applied.
[0017]
Further, the surface of the base coat 14 is coated with a colorless fluororesin as the top coat 15 to a thickness of 5 to 50 μm (25 μm in the present embodiment). In addition, as the fluororesin used for the base coat 14 and the top coat 15, it is preferable to use polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkylvinylether copolymer (PFA), or the like, which has excellent 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 a non-plated portion X, and a copper plated layer 13 serving as a joining metal layer is provided on 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 a non-plated portion X, and a copper plating layer 13 serving as a bonding metal layer is provided on the remaining portion.
[0019]
The aluminum plate 11 and the stainless steel plate 12 are concentrically laminated and arranged with the copper plating layer 13 interposed therebetween, and are hot-pressed (hot uniaxial pressing method) so as to be joined to each other to form a clad material. The 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 pressing is performed under reduced pressure or vacuum under the 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. Thus, the non-joined portion can be the vacuum portion 16, the interposition of gas molecules at the joint interface can be reduced, and the diffusion of the metals to be joined can be promoted.
[0021]
The non-magnetic metal plate is not particularly limited as long as it has good thermal conductivity and becomes a heat transfer layer. Materials such as aluminum, an aluminum alloy, and non-magnetic stainless steel are suitably used. The aluminum plate 1 is used because the conductivity and workability are improved. The aluminum plate 11 has a thickness of 0.5 to 5.0 mm (1.7 mm in the present embodiment) from the viewpoint of strength, thermal conductivity, and the like, and the thickness of the copper plating layer 13 on the lower surface side is The thickness is 1 to 50 μm (10 μm in the present embodiment).
[0022]
The magnetic metal plate is not particularly limited as long as an eddy current flows by a high-frequency magnetic field and becomes a heat generating layer. 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 plate 12 has a thickness of 0.1 to 3.0 mm (0.5 mm in the present embodiment), and the thickness of the copper plating layer 13 on the upper surface side is 1 to 50 μm (in the present embodiment, 10 μm).
The copper plating layer 13 may be replaced with aluminum, nickel, and / or 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 having the vacuum portion 16 continuously arranged along the entire periphery of the peripheral wall 10b is obtained. A bottomed cylindrical member 10 is formed. The bottomed cylindrical member 10 has a flange 10d protruding from the peripheral edge of the opening at the distal end, and a peripheral wall 10b adjacent to the flange 10d has an enlarged diameter portion 10c curved in an enlarged diameter. 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 enlarged diameter portion 10c is set to R1 = 5T to 9T (mm) when the thickness of the clad material is T (mm).
[0024]
Next, a molding step of adjusting the bottomed cylindrical material 10 to a predetermined shape by press molding (secondary press) is performed.
[0025]
The molding die includes an upper molding die 20 and a lower molding die 30 as shown in FIG.
The lower molding die 30 has a substantially cylindrical mold portion 30a to be fitted inside the inverted bottomed cylindrical material 10 and a flange portion protruding laterally at a lower end edge of the mold portion 30. 30b is provided.
Further, as shown in FIG. 3, the cylindrical diameter of the mold portion 30a is large enough to leave a mold release gap L (mm) between the peripheral wall 10b of the bottomed cylindrical material 10 to be fitted and the mold portion 30a. The range of the gap L is 0.05 to 0.15 mm.
[0026]
The upper molding die 20 has an annular tip 22 made of an HZ alloy made of a high hardness, abrasion resistant and lubricating material at a lower end of a mold main body 21 fitted to the inverted bottomed cylindrical member 10. It is continuous, and the mold part 23 is recessed inside.
The inner peripheral tip of the distal end portion 22 has a radius portion 22a curved in an enlarged shape. The radius is smaller than the radius of curvature R1 of the diameter portion 10c.
A step 21a is provided on the mold surface at one end boundary position A of the vacuum portion 16 of the bottomed cylindrical member 10 of the mold body 21 to reduce the diameter of the mold surface, and the mold from the step 21a to the round portion 22a of the tip end portion 22 is formed. The plane is vertical.
[0027]
As shown in FIG. 2, the bottomed cylindrical member 10 is inverted and fitted to the mold portion 30 a of the lower molding die 30, and the upper molding die 20 is lowered toward the lower molding die 30, as shown in FIG. 4. Then, it is externally fitted to the bottomed cylindrical material 10 externally fitted to the mold portion 30a of the upper molding die 30 and pressed.
As a result, the curved enlarged diameter portion 10c on the side of the flange 10d of the peripheral wall 10b of the bottomed cylindrical member 10 is pressed inward by the upper molding die 20 so as to be vertically corrected and adjusted to have an L-shaped cross section.
[0028]
When the upper mold 20 is lowered toward the lower mold 30, as shown in FIG. 3, the peripheral wall 10 b of the bottomed cylindrical material 10 is lowered toward the lower mold 30 by the upper mold 20. As a result, the rolling effect can be obtained, and the joining strength at the other end boundary position B of the vacuum portion 16 can be increased.
At this time, the tip portion 22 of the upper mold 20 to which a large load is applied is made of an HZ alloy having high hardness and abrasion resistance and lubricity, so that the pressing operation can be performed smoothly without wear. .
[0029]
Further, a clearance L for mold release between the peripheral wall 10b between the one end boundary position A and the front end of the peripheral wall 10b continuous with the flange 10d and the convex mold surface 30a of the lower molding die 30 is set to 0.05 to 0.05. Since it is provided about 0.15 mm, it can be released smoothly from the molded state as shown in FIG. The separation can be prevented 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 21a of the upper molding die 20 strongly presses the outer surface corresponding to one end boundary position A of the vacuum portion 16 of the bottomed cylindrical member 10 against the lower molding die 30 to form a step 10e. Therefore, the joining strength at the boundary position A at one end of the vacuum section 16 can be increased.
[0031]
Therefore, the bottomed cylindrical member 10 formed by the drawing press working (primary press) is press-formed into a predetermined shape (secondary press), and at the same time, the boundary positions A and B at both ends of the vacuum portion 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 section 16 without increasing the number of work steps. be able to.
[0032]
Next, by performing a short-time heat treatment at 250 to 300 ° C. on the bottomed cylindrical member 10 ′ shown in FIG. 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, as shown in FIG. 6, the aluminum plate 11 and the stainless steel plate 12 are automatically To form an electromagnetic induction heating vessel 10 "in which the vacuum portion 16 is enlarged.
That is, in the heat treatment, since the enlarged formation of the vacuum layer 16 is also used as the sintering step of the fluororesin for coloring, the number of working steps can be reduced, and complicated steps such as welding are required. Without this, it is possible to obtain the electromagnetic induction heating container 10 ″ having the vacuum section 16 very easily and inexpensively.
[0034]
【The invention's effect】
As is apparent from the above description, according to the present invention, when press-forming a bottomed cylindrical material having a vacuum portion on a peripheral wall formed by drawing press working into a predetermined shape with a vertical molding die, By pressing the peripheral wall of the lower mold toward the lower mold with the descending upper mold, a rolling effect is obtained, and the bonding strength at the boundary position of the other end of the vacuum section can be increased.
Also, the step of reducing the diameter of the upper molding die strongly presses the one end boundary position of the vacuum part against the lower molding die, so that the bonding strength at the one end boundary position of the vacuum part can be increased.
Therefore, at the same time as the bottomed cylindrical material formed by drawing press working is pressed into a predetermined shape, the joining strength can be improved by strongly pressing the boundary portions at both ends of the vacuum portion, without increasing the number of work steps In addition, it is possible to prevent the metal plates from being separated 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 mold for press molding.
FIG. 3 is an enlarged cross-sectional view of a main part during press forming.
FIG. 4 is a cross-sectional view of a state where an upper mold is pressed down.
FIG. 5 is a cross-sectional view of the bottomed cylindrical material after press forming.
FIG. 6 is a cross-sectional view of a bottomed cylindrical material after a heat treatment.
FIG. 7 is a schematic sectional view of a clad material.
FIGS. 8A and 8B are explanatory views of drawing press working.
[Explanation of symbols]
Reference Signs List 10 bottomed cylindrical material 10a bottom wall 10b peripheral wall 10c enlarged diameter portion 10d flange 11 aluminum plate (non-magnetic metal plate)
12 Stainless steel plate (magnetic metal plate)
13 Copper plating layer (metal layer for joining)
14 Base coat (fluororesin layer)
15 Top coat (fluororesin layer)
16 Vacuum part 20 Upper mold 21 Mold body 21a Step 22 Tip 22a Round part 23 Mold 30 Lower mold 30a Mold part A One end boundary position B Other end boundary position L Gap X Non-plated part

Claims (4)

A non-joined vacuum part is provided in a part of the clad material in which the metal plates are joined together, and the clad material is drawn and pressed to form a bottomed cylindrical material having a vacuum part on the peripheral wall and a flange protruding from the peripheral edge of the tip opening. Forming, said bottomed cylindrical material is a method of molding as a container of a predetermined shape with a vertical molding die,
The lower molding die has a protruding mold portion that fits inside the inverted bottomed cylindrical material, while the upper molding die presses down toward the lower molding die. A mold part externally fitted to the bottom cylindrical material is recessed, and a step is formed on a mold surface of the mold part which is located at one end boundary position between one end of a vacuum part provided on the peripheral wall of the bottomed cylindrical material and a joint part on the bottom wall side. The bottom wall side mold surface is provided to reduce the 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 joining portion of the flange side peripheral wall and the step is vertical. ,
When forming the bottomed cylindrical material with the upper and lower forming dies, the peripheral wall adjacent to the flange of the bottomed cylindrical material presses inward the portion where the diameter is curved so as to be inwardly straightened, and the other portions are vertically corrected. A method for manufacturing a container having a vacuum part, wherein the joining strength at the end boundary position is increased while the joining strength at the end boundary position is increased by the step. The tip of the mold part of the upper mold that forms the flange and the peripheral wall of the bottomed cylindrical material is formed of a separate member made of a high-strength HZ alloy material, and the peripheral wall having the vacuum part is radially inward. The method for manufacturing a container having a vacuum section according to claim 1, wherein the container is pressed with a 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 is formed between the flange mounted surface of the lower forming die. 3. The method for manufacturing a container having a vacuum part according to claim 2, wherein the horizontal flange is formed so as to protrude with a radius smaller than a vertical peripheral wall tip. A clearance of about 0.05 to 0.15 mm is provided between the peripheral wall between the one end boundary position and the front end of the peripheral wall continuous with the flange and the convex mold surface of the lower molding die for mold release. A method for manufacturing a container having a vacuum section according to any one of claims 1 to 3.

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