JP6024833B2 - Forming method of cylindrical container with bottom - Google Patents

Description

  The present invention relates to a molding method for increasing the thickness of a container shoulder portion of a cylindrical container with a bottom, forming the container at a right angle, and forming a container side wall portion in a straight line.

  For example, in the case of parts that transmit torque by rotating, such as drums and hubs used in automobile automatic transmissions, the shoulder connecting the bottom and the side wall perpendicular to the bottom is formed into a right angle and transmitted. It is required to have a sufficient thickness to withstand torque. Further, the side wall portion is also required to have a sufficient thickness.

FIG. 1 is a view showing a state of a mold and a cylindrical container 11 with a bottom before molding in a conventional molding method. In the conventional molding method, first, the container bottom 11 a of the bottomed cylindrical container 11 is held between the inner punch 12 and the die 14. Subsequently, the container side wall 11b in the space surrounded by the inner punch 12, the outer punch 13, and the die 14 is pushed into the die bottom 14a side by the outer punch 13 as shown in FIG. The part 11c is increased in thickness and formed into a right angle, and the container side wall part 11b is formed in a straight line.
However, in the conventional method, the outer punch 13 is deformed in the plate thickness direction as indicated by the dotted line in FIG. 1 while the container opening end 11d is being pushed toward the die bottom 14a, and the inner side of the container shoulder 11c is the inner punch 12. You may get away from the punch shoulder. In this case, as shown in FIG. 2, there is a problem in that a bowl-shaped ridge 11d (called a fold-up fold) is formed inside the container shoulder 11c so that the surface is folded and overlapped. is there.

Patent Document 1 discloses a molding method that suppresses the occurrence of folding wrinkles. This molding method forms the container shoulder portion into an obtuse angle, and shapes the container shoulder portion at a right angle. It is not a thing. Moreover, in this shaping | molding method, a container side wall part bends.
Patent Document 2 discloses a molding method in which a container shoulder is thickened at a right angle using a pressure roller, but this molding method requires a special device such as a pressure roller.
In Patent Document 3, in order to prevent defects due to buckling, the vertical wall of an intermediate product that has been previously formed into a cup shape is ironed with a die and a punch to form a wall in the vertical wall near the inner periphery of the corner. A molding method is disclosed in which the outer periphery of the corner is squared by pressing the meat reservoir with a punch and moving the meat in the reservoir to the corner of the outer periphery of the corner. However, this molding method requires a special process of ironing to form a meat pool before the squaring.
In Patent Document 4, the outer shape of the presser punch and the presser punch is provided in order to provide a molding method that does not have wrinkles when the bottom part and the wall part are formed at right angles by increasing the corners of the cylindrical cup. The deep-drawn cup is placed on the press punch using a die having an upset punch and a die that are arranged in the axial direction and movable relative to the press punch in the axial direction. When forming by pushing up the upsetting punch, press the holding punch and upsetting punch to 0.5 times or more and 0.7 times or less of each full stroke (first step), and continue to press only the presser punch. Pressing from 0.8 times to 0.9 times the full stroke of the punch (second step), then pressing the presser punch and upsetting punch to the full stroke (third step) and forming to form The law has been disclosed. However, in this forming method, it is necessary to move the presser punch and the upsetting punch to the first to third steps, and an ordinary double-action press requires three steps. Moreover, in order to perform the 1st-3rd process continuously with one press machine, an expensive double-acting servo press machine is required.

JP 2001-47175 A JP 2007-289989 A Japanese Patent Laid-Open No. 9-327749 JP 2014-911146 A

  The present invention has been made in view of the above circumstances, and increases the container shoulder of the bottomed cylindrical container while suppressing the occurrence of folding wrinkles without requiring special equipment or special processing in the previous stage. An object is to form the container side wall at right angles and form the container side wall in a straight line.

The gist of the present invention for solving the above-mentioned problems is as follows.
[1] A method of forming a bottomed cylindrical container using a bottomed cylindrical container having a container bottom, a container side wall, and a curved container shoulder connecting the container bottom and the container side wall as a workpiece,
Mutually central axes are arranged coaxially,
With an inner punch,
An annular first outer punch disposed along the outer periphery of the inner punch and having an R-shaped punch shoulder at an outer edge in a direction perpendicular to the central axis of the press surface portion;
An annular second outer punch that is disposed along an outer periphery of the first outer punch and that pushes in a container opening end of the bottomed cylindrical container;
A die bottom and a die side wall connected perpendicularly to an outer edge of the die bottom, and a die disposed opposite to the inner punch, the first outer punch and the second outer punch, and
In a state where the container bottom is sandwiched between the inner punch and the die, and in a state where the container opening end is constrained by the side wall portion of the first outer punch and the die side wall portion of the die. The outer shoulder of 1 and the second outer punch are relatively moved toward the bottom of the die of the die, thereby increasing the thickness of the container shoulder and forming the container side wall at the center. A method for forming a cylindrical container with a bottom, comprising a step of linearly forming in a direction along an axis.
[2] In the first outer punch and the second outer punch, a step groove portion is formed on the press surface portion through the R-shaped punch shoulder portion, and the bottom portion of the step groove portion forms the bottom. The method for forming a bottomed cylindrical container according to [1], characterized in that the bottomed cylindrical container is configured as one annular punch configured to push the container open end of the cylindrical container with a bottom.
[3] The second outer punch is pushed into contact with the container opening end simultaneously with or after the R-shaped punch shoulder comes into contact with the container shoulder [1] or The method for forming a cylindrical container with a bottom according to [2].
[4] having a post-process for increasing the thickness of the container side wall portion of the bottomed cylindrical container in the plate thickness direction after the molding by the above-described process;
The post-process
Mutually central axes are arranged coaxially,
An internal punch for thickening,
An annular outer punch for increasing the thickness arranged along the outer periphery of the inner punch for increasing the thickness;
Using a die-thickening die having a die side wall portion connected perpendicularly to an outer edge portion of the die bottom portion and the die bottom portion, and a die for thickening disposed facing the inner punch for thickening and the outer punch for thickening,
In the state where the container bottom is sandwiched by the inner punch for thickening and the die for thickening, the container side wall is a gap between the inner punch for thickening and the die side wall of the die for thickening The outer punch for thickening arranged in a gap larger than the plate thickness of the portion is relatively moved toward the bottom of the die of the die for thickening, so that the side wall of the container is installed and the thickness is increased in the plate thickness direction. A method for forming a bottomed cylindrical container as described in [1].
[5] The bottomed cylindrical container according to [4], wherein the shape of the punch shoulder portion of the inner punch for thickening is equivalent to the shape of the R-shaped punch shoulder portion in the first step. Molding method.

  According to the present invention, without the need for special processing or special processing in the previous stage, while suppressing the occurrence of folding wrinkles, the container shoulder of the bottomed cylindrical container is increased in thickness and formed into a right angle, And a container side wall part can be shape | molded linearly.

FIG. 1 is a cross-sectional view showing a mold before molding and a cylindrical container with a bottom in a conventional molding method. FIG. 2 is a cross-sectional view showing a mold and a cylindrical container with a bottom after molding by a conventional molding method. FIG. 3 is a cross-sectional view showing a mold and a cylindrical container with a bottom before molding in the first step according to the embodiment. FIG. 4 is a cross-sectional view showing a mold and a cylindrical container with a bottom during molding in the first step according to the embodiment. FIG. 5 is a cross-sectional view showing a mold and a cylindrical container with a bottom during molding in the first step according to the embodiment. FIG. 6 is a cross-sectional view showing a mold and a cylindrical container with a bottom during molding in the first step according to the embodiment. FIG. 7 is a cross-sectional view showing a mold and a cylindrical container with a bottom during molding in the first step according to the embodiment. FIG. 8 is a cross-sectional view showing the mold and the cylindrical container with the bottom after the first step according to the embodiment. FIG. 9 is a cross-sectional view showing a mold before molding and a cylindrical container with a bottom in the second step according to the embodiment. FIG. 10 is a cross-sectional view showing a mold and a cylindrical container with a bottom during molding in the second step according to the embodiment. FIG. 11 is a cross-sectional view showing the mold and the cylindrical container with the bottom after the second step according to the embodiment. FIG. 12 is a cross-sectional view showing a mold and a cylindrical container with a bottom before molding in a comparative example. FIG. 13A is a cross-sectional view showing a mold and a cylindrical container with a bottom during molding in a comparative example. FIG. 13B is an enlarged cross-sectional view showing a mold during molding and a cylindrical container with a bottom in a comparative example. FIG. 14A is a cross-sectional view showing a mold and a cylindrical container with a bottom during molding in a comparative example. FIG. 14B is an enlarged cross-sectional view showing a mold during molding and a cylindrical container with a bottom in a comparative example. FIG. 15A is a cross-sectional view showing a mold after molding and a cylindrical container with a bottom in a comparative example. FIG. 15B is an enlarged cross-sectional view showing a mold and a cylindrical container with a bottom after molding in a comparative example. FIG. 16: is sectional drawing which shows the metal mold | die and bottomed cylindrical container before shaping | molding of the 1st process which concerns on a modification.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.
In the method for forming a bottomed cylindrical container according to this embodiment, the first press mold is used to increase the thickness of the container shoulder of the bottomed cylindrical container and to form the container at a right angle, and to linearly form the container side wall. It has the 1st process to shape | mold, and the 2nd process of thickening a container side wall part in a plate | board thickness direction using a 2nd press die after a 1st process.

(First step)
FIG. 3 is a cross-sectional view illustrating a mold (first press mold) and a cylindrical container with a bottom before molding in the first step according to the embodiment. In addition, since the side cross section of the 1st press die and the 2nd press die mentioned later is an axis | shaft object, only one side part is shown from a central axis. The same applies to the other drawings.

  The molding object (work material) of the press machine in the first step is a bottomed cylindrical container 21 having a container bottom 21a, a container side wall 21b, and a curved container shoulder 21c connecting the container bottom 21a and the container side wall 21b. It is. The bottomed cylindrical container 21 that is a workpiece is formed in advance by drawing.

  The first press die has an inner punch 22, an outer punch 23, a knockout 24, and a die 25 whose central axes 20 are arranged coaxially with each other. The die 25 is fixed, and the other elements 22 to 23 can be moved up and down by a lifting mechanism. A hydraulic pressure, a servo motor or the like can be used for the lifting mechanism. Further, since the inner punch 22 only needs to be able to hold the container bottom 21a with the die 25, a spring or the like that applies an urging force in the direction of the die 25 can be used.

  The inner punch 22 has a columnar shape, and includes a flat press surface portion 22a facing the knockout 24 and the die 25, and an outer peripheral surface portion 22b.

  The outer punch 23 is formed in an annular shape and is disposed along the outer peripheral surface portion 22 b of the inner punch 22. The outer punch 23 has a first press surface portion 23a that is annular in plan view and that faces the die 25, and an outer peripheral surface portion 23b. An annular step groove 23c is formed on the outer edge in the radial direction orthogonal to the central axis 20 of the first press surface portion 23a. The step groove portion 23c includes a circumferential side wall portion 23d and an annular bottom surface portion (referred to as a second press surface portion) 23e that is orthogonal to the side wall portion 23d. The side wall portion 23d and the first press surface portion 23a are connected by an R-shaped punch shoulder portion 23f. The outer diameter of the side wall 23d of the step groove 23c is substantially equal to the inner diameter of the container side wall 21b of the bottomed cylindrical container 21.

  The knockout 24 has a columnar shape and is used for removing the bottomed cylindrical container 21 formed by the first press mold from the first press mold, and is movable up and down by a mechanical drive source (not shown). It is a formula.

  The die 25 has a die bottom portion 25a and an annular die side wall portion 25b connected perpendicularly to the outer edge portion of the die bottom portion 25a. A hole 25c in which the knockout 24 is disposed is formed at the center of the die bottom 25a. The inner diameter of the die side wall 25b is substantially equal to the outer diameter of the container side wall 21b.

Hereinafter, the first step will be described.
In the first step, the press machine lowers the inner punch 22 with respect to the bottomed cylindrical container 21 placed on the die 25 so that the container bottom 21a is held between the inner punch 22 and the die 25. The outer punch 23 is lowered while maintaining the state.

As shown in FIG. 3, the outer punch 23 is lowered, and the container opening end 21 d of the bottomed cylindrical container 21 enters the stepped groove 23 c of the outer punch 23. At this time, the container opening end 21d is separated from the second press surface portion 23e of the outer punch 23, and is restrained from the direction perpendicular to the central axis 20 by the step groove portion 23c and the die side wall portion 25b.
As shown in FIG. 4, when the outer punch 23 is further lowered, the punch shoulder 23f comes into contact with the container shoulder 21c, and the container shoulder 21c and the container side wall 21b are deformed downward. Although the container bottom 21a has been described as being held in advance by the inner punch 22 and the die 25, the container bottom 21a only needs to be held when the punch shoulder 23f contacts the container shoulder 21c. That is, the timing may be such that the container bottom 21a is held between the inner punch 22 and the die 25 at the same time or immediately before the punch shoulder 23f contacts the container shoulder 21c.

  As shown in FIG. 5, when the outer punch 23 is further lowered, the second press surface portion 23e of the step groove portion 23c comes into contact with the container opening end 21d, and the container opening end 21d is pressed by the second press surface portion 23e. The container shoulder portion 21c and the container side wall portion 21b are deformed downward. That is, at the same time as or after the punch shoulder portion 23f comes into contact with the container shoulder portion 21c, the second press surface portion 23e of the step groove portion 23c comes into contact with and pushes into the container opening end 21d.

  As shown in FIGS. 6 and 7, when the outer punch 23 is further lowered, the container shoulder 21c is gradually pushed toward the die corner 25d, which is the boundary between the die bottom 25a and the die side wall 25b. A portion on the container shoulder 21c side of 21a is thickened. At this time, the contact range between the punch shoulder portion 23f and the bottomed cylindrical container 21 is expanded in the direction of the first press surface portion 23a of the outer punch 23, so that the bottomed cylindrical container 21 is folded at the punch shoulder portion 23f. Can be prevented. In other words, the container side wall part 21b, the container shoulder part 21c, and the container bottom part 21a are formed while restraining deformation of the container side wall part 21b in the plate thickness direction and bringing the punch shoulder part 23f into close contact with the container shoulder part 21c. Therefore, it is possible to suppress the occurrence of folding wrinkles inside the container shoulder 21c.

  From the state shown in FIG. 7, the outer punch 23 is further lowered. At this time, in addition to pushing the container side wall portion 21b with the second press surface portion 23e of the outer punch 23, the portion on the container shoulder portion 21c side increased in the container bottom portion 21a is replaced with the first press surface portion 23a and the punch shoulder portion. By pressing down with 23f, as shown in FIG. 8, the thickened portion of the container bottom 21a is caused to flow into the space of the die corner 25d, and the container shoulder 21c is thickened and formed into a right angle.

  By the above first step, the container shoulder 21c can be increased in thickness and formed into a right angle, and the container side wall 21b can be formed linearly in the direction along the central axis 20. After the molding in the first step, the press raises the inner punch 22, the outer punch 23, and the knockout 24, and removes the bottomed cylindrical container 21 from the die 25.

(Second step)
FIG. 9 is a cross-sectional view showing a mold (second press mold) and a cylindrical container with a bottom before molding in the second step according to the embodiment.
The molding object (work material) of the press machine in the second step is a bottomed cylindrical container after molding in the first step, and hereinafter, the symbol of the bottomed cylindrical container after molding in the first step is 31, The parts of the bottomed cylindrical container 31 are referred to as a container bottom part 31a, a container side wall part 31b, a container shoulder part 31c, and a container opening end 31d.

  The second press die includes an inner punch 32 (inner punch for increasing the thickness), an outer punch 33 (outer punch for increasing the thickness), a knockout 34, and a die 35 (for increasing the thickness) whose central axes 30 are arranged coaxially. Die). The die 35 is fixed, and the other elements 32 to 33 can be moved up and down by a lifting mechanism. A hydraulic pressure, a servo motor or the like can be used for the lifting mechanism. Further, since the inner punch 32 only needs to be able to hold the container bottom portion 31a with the die 35, a spring or the like that applies a biasing force in the direction of the die 35 can be used.

  The inner punch 32 has a cylindrical shape, and includes a flat press surface portion 32a facing the knockout 34 and the die 35, an outer peripheral surface portion 32b, and an inner punch shoulder portion 32c connecting the flat surface portion 32a and the outer peripheral surface portion 32b. The outer diameter of the outer peripheral surface portion 32 b of the inner punch 32 is substantially equal to the inner diameter of the container side wall portion 31 b of the bottomed cylindrical container 31. The shape of the inner punch shoulder 32c is substantially the same as the shape of the punch shoulder 23f of the outer punch 23 used in the first step.

  The outer punch 33 is formed in an annular shape and is disposed along the outer peripheral surface portion 32 b of the inner punch 32. The outer punch 33 has a press surface portion 33 a that is annular in plan view and faces the die 35. The thickness of the outer punch 33 (thickness in the direction orthogonal to the central axis 30) is larger than the plate thickness T of the container side wall 31b.

  The knockout 34 has a columnar shape for removing the bottomed cylindrical container 31 after being molded by the second press mold from the second press mold, and is movable up and down by a mechanical drive source (not shown). It is a formula.

  The die 35 has a die bottom portion 35a and an annular die side wall portion 35b connected perpendicularly to the outer edge portion of the die bottom portion 35a. A hole 35c in which the knockout 34 is disposed is formed at the center of the die bottom 35a. The inner diameter of the die side wall 35b is larger than the outer diameter of the container side wall 31b in order to increase the thickness of the container side wall 31b. That is, a gap is formed between the container side wall portion 31b and the die side wall portion 35b. The space S1 between the die side wall 35b and the inner punch 32 is larger than the plate thickness T of the container side wall 31b, and the outer punch 33 is disposed in the gap S1.

Hereinafter, the second step will be described.
In the second step, the press machine lowers the inner punch 32 with respect to the bottomed cylindrical container 31 placed on the die 35 and holds the container bottom 31a between the inner punch 32 and the die 35. The outer punch 33 is lowered while maintaining the state.

  As shown in FIGS. 10 and 11, the outer punch 33 is lowered, and the container side wall portion 31b is installed in the space surrounded by the inner punch 32, the outer punch 33, and the die 35 to increase the thickness in the plate thickness direction. To do.

  At this time, in addition to the container shoulder portion 31c being formed in a shape that contacts the inner punch shoulder portion 32c in the first step, the container shoulder portion 31c is formed in the middle of the second step. Does not leave the inner punch shoulder 32c. Therefore, it is possible to suppress the occurrence of folding wrinkles inside the container shoulder 31c.

  By the above second step, the container side wall 31b can be thickened in the thickness direction. After the molding in the second step, the press raises the inner punch 32, the outer punch 33, and the knockout 34, and removes the bottomed cylindrical container 31 from the die 35.

As a comparative example, as shown in FIG. 12, a case will be described in which the second step is performed in a state where the container shoulder is not formed into a right angle. In addition, the code | symbol of a cylindrical container with a bottom is set to 41, and each part of the cylindrical container 41 with a bottom is described as the container bottom part 41a, the container side wall part 41b, the container shoulder part 41c, and the container opening end 41d.
In this case, a gap S2 is generated between the inner punch shoulder portion 32c and the container shoulder portion 41c as shown in FIGS. 13A and 13B during the second step. Then, as shown in FIGS. 14A, 14B, 15A, and 15B, the material of the bottomed cylindrical container 41 protrudes into the gap S2, and a fold 41e is generated inside the container shoulder 41c. Therefore, in the first step, it is necessary to carry out the thickening process until the container shoulder 41c is formed in a right angle.

The bottomed cylindrical container 21 may be made of various known materials that can be plastically processed, such as steel, aluminum, a metal such as a trunk, or an alloy thereof.
In addition, it has been described that the bottomed cylindrical container 21 is formed in advance by drawing. The cylindrical container 21 may be formed.

As mentioned above, although this invention was demonstrated with various embodiment, this invention is not limited only to these embodiment, A change etc. are possible within the scope of the present invention.
(Modification 1)
In the above-described embodiment, in the first press die, the outer punch 23 is formed with the step groove portion 23c that is connected to the press surface portion 23a via the R-shaped punch shoulder portion 23f, and the bottom surface portion 23e of the step groove portion 23c. Although the example comprised as a single cyclic | annular punch which pushes in the container opening end 21d of the cylindrical container 21 with a bottom was demonstrated, this invention is not limited to this. As shown in FIG. 16, an annular first outer punch 23I is disposed along the outer periphery of the inner punch 22 and has an R-shaped punch shoulder 23f on the outer edge in a direction perpendicular to the central axis 20 of the press surface portion 23a. And an annular second outer punch 23O that is arranged along the outer periphery of the first outer punch 23I and that pushes in the container opening end 21d of the bottomed cylindrical container 21. However, it is preferable to configure the outer punch 23 as one punch because only one lifting mechanism is required.

(Modification 2)
In the above-described embodiment, in the first step, the outer punch 23 is lowered while the inner punch 22, the knockout 24, and the die 25 are fixed, so that the container shoulder portion 21c is formed into a right angle while increasing the thickness. However, the present invention is not limited to this. That is, in the first step, the outer punch 23 may be fixed and the inner punch 22, the knockout 24, and the die 25 may be raised to form the container shoulder portion 21c in a right angle while increasing the thickness. Alternatively, the inner punch 22, the knockout 24, and the die 25 may be raised while lowering the outer punch 23, thereby forming the container shoulder portion 21c in a right-angle shape while increasing the thickness.

(Modification 3)
In the above-described embodiment, in the second step, the outer side wall 33b is increased by lowering the outer punch 33 while the inner punch 32, the knockout 34, and the die 35 are fixed. It is not limited. That is, in the second step, the container side wall 21b may be increased by raising the inner punch 32, the knockout 34, and the die 35 with the outer punch 33 fixed. Further, the container side wall portion 21b may be increased by raising the inner punch 32, the knockout 34, and the die 35 while lowering the outer punch 33.

(Modification 4)
In the above-described embodiment, the upper and lower sides of each tool may be reversed. In the above-described embodiment, the knockouts 24 and 34 are provided. However, the knockouts 24 and 34 may be omitted. In this case, the hole 25a of the die 25 may be omitted, and the entire container bottom 21a may be supported by the die 25. Further, the hole 35c of the die 35 may be omitted, and the entire container bottom 31a may be supported by the die 35. The bottomed cylindrical container after the first step or the second step may be removed from the dies 25 and 35 using, for example, a lifting machine.

  The present invention can be used to mold a cylindrical container with a bottom, which is a part that rotates and transmits torque, such as a drum or a hub used in an automatic transmission of an automobile.

Claims (5)

A bottomed cylindrical container molding method using a bottomed cylindrical container having a container bottom, a container side wall, and a curved container shoulder connecting the container bottom and the container side wall,
Mutually central axes are arranged coaxially,
With an inner punch,
An annular first outer punch disposed along the outer periphery of the inner punch and having an R-shaped punch shoulder at an outer edge in a direction perpendicular to the central axis of the press surface portion;
An annular second outer punch that is disposed along an outer periphery of the first outer punch and that pushes in a container opening end of the bottomed cylindrical container;
A die bottom and a die side wall connected perpendicularly to an outer edge of the die bottom, and a die disposed opposite to the inner punch, the first outer punch and the second outer punch, and
In a state where the container bottom is sandwiched between the inner punch and the die, and in a state where the container opening end is constrained by the side wall portion of the first outer punch and the die side wall portion of the die. The outer shoulder of 1 and the second outer punch are relatively moved toward the bottom of the die of the die, thereby increasing the thickness of the container shoulder and forming the container side wall at the center. A method for forming a cylindrical container with a bottom, comprising a step of linearly forming in a direction along an axis.   The first outer punch and the second outer punch are formed with a step groove portion continuously provided on the press surface portion via the R-shaped punch shoulder portion, and the bottomed cylindrical container at the bottom surface portion of the step groove portion. The method for forming a cylindrical container with a bottom according to claim 1, wherein the container is configured as a single annular punch for pushing the open end of the container.   The said 2nd outer punch is pushed in contact with the said container opening end at the same time after the said R-shaped punch shoulder part contacts the said container shoulder part, or 2 characterized by the above-mentioned. Method for forming cylindrical container with bottom. A post-process for increasing the thickness of the container side wall of the bottomed cylindrical container after the molding by the process in the thickness direction;
The post-process
Mutually central axes are arranged coaxially,
An internal punch for thickening,
An annular outer punch for increasing the thickness arranged along the outer periphery of the inner punch for increasing the thickness;
Using a die-thickening die having a die side wall portion connected perpendicularly to an outer edge portion of the die bottom portion and the die bottom portion, and a die for thickening disposed facing the inner punch for thickening and the outer punch for thickening,
In the state where the container bottom is sandwiched by the inner punch for thickening and the die for thickening, the container side wall is a gap between the inner punch for thickening and the die side wall of the die for thickening The outer punch for thickening arranged in a gap larger than the plate thickness of the portion is relatively moved toward the bottom of the die of the die for thickening, so that the side wall of the container is installed and the thickness is increased in the plate thickness direction. The method for forming a cylindrical container with a bottom according to claim 1, wherein:   The method for forming a cylindrical container with a bottom according to claim 4, wherein the shape of the punch shoulder portion of the inner punch for thickening is equivalent to the shape of the R-shaped punch shoulder portion in the first step. .

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