JP2003128060A - Transformed seamless can and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transformed seamless can that is hard to buckle when load is applied in the direction of its body height, and that does not buckle from a tapered part by axial load at the time of wind-fastening. SOLUTION: The transformed seamless can 1 comprises a body part 2 that is constituted of an upper part 2a having a cylindrical form and a lower part 2b having a form of a frustum of a reverse cone, with a thick-wall part 2f being provided at the border portion between the upper part 2a and the lower part 2b or in the vicinity thereof. The can is also characterized in that the lower part 2b is bent inward or in a tapered state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modified seamless can used for carbonated beverage cans, beer cans, coffee beverage cans, fruit beverage cans and the like, and a method for producing the same. The present invention relates to a modified seamless can having a thick portion and a method for manufacturing the same.

[0002]

2. Description of the Related Art Squeeze-ironing cans (so-called DI cans) and squeezers, which have been conventionally used for carbonated beverage cans, coffee beverage cans, etc.
In conventional seamless cans such as re-drawing cans, the body of the can, except the neck-in part, has a uniform cylindrical shape over the entire height. Then, when conveyed while being shaken at a high speed, the bottom corner of the adjacent empty can hits the can body, causing defects such as dents in the can body. When used for so-called negative pressure canned products (canned products whose internal pressure is lower than atmospheric pressure) filled with coffee drinks, fruit drinks, etc., the can body is easily dented. When several stages are stacked on a refrigerating shelf such as a supermarket without any gap, the one placed near the center requires a relatively long time for cooling because the circulation of cold air is poor. There was a problem. In order to solve these problems, the present inventors previously proposed "deformed seamless can" (Japanese Patent Laid-Open No. 7-242226).

[0003]

However, in the modified seamless can described above, since the lower part of the can body has an inverted truncated cone shape, the can is formed at the boundary between the upper part and the lower part or in the vicinity thereof. Buckling tends to occur when a load is applied in the body height direction. For example, the deformed seamless can has a problem that it is apt to buckle due to an axial load during tightening. As a countermeasure for this, the buckling strength can be increased by simply increasing the thickness of the can body as a whole, but in that case, the amount of material used is too large, which is not preferable because of high cost. The present invention, when transported while vibrating at high speed in close contact with the conveyor in the empty can state, it is unlikely to cause defects such as dents in the can body.
Even when used for negative pressure canning, the body of the can is difficult to dent, and even when it is stacked in several stages on a refrigerating shelf without a gap, the cans placed near the center can be cooled relatively quickly. An object of the present invention is to provide a deformed seamless can in which the buckling strength in the can body height direction is improved with a limited amount of materials used, and a manufacturing method thereof.

[0004]

A modified seamless can according to the present invention has a can body composed of an upper part having a cylindrical shape and a lower part having an inverted truncated cone shape, and at least the upper part and the lower part. It is characterized in that a thick wall portion is provided at or near the boundary portion with the portion. In such a modified seamless can, it is preferable that the lower part is curved inward or tapered.

The method for producing a modified seamless can of the present invention is
After ironing a metal cup with a punch having a reduced diameter portion to produce an ironing can body in which a thick portion corresponding to the reduced diameter portion is formed, the lower part of the ironing can body is placed outside the ironing can body. The diameter is reduced by a diameter reduction die having a hole smaller than the diameter, and then the reduced lower portion is expanded and formed into an inverted truncated cone shape, and a thick wall is formed at least at or near the boundary between the upper portion and the lower portion. It is characterized in that a part is provided.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In a modified seamless can of the present invention, an upper part of a can body has a cylindrical shape, and a lower part has an inverted truncated cone shape, and at least the upper part and the lower part. A thick part is provided at or near the boundary part. The lower portion is preferably curved inward, and is preferably tapered downward. Therefore, even when empty cans are conveyed while vibrating at high speed on the conveyor in the can making process, filling process, etc.
Since there is a considerable gap between the adjacent bottoms of the empty cans, it is unlikely that a defect such as a dent occurs in the can body due to the bottom corner of the adjacent can hitting the can body. And, even when the upper part is stacked in several stages on a refrigerating shelf such as a supermarket without any gaps, since there is a considerable gap in the lower part of the adjacent cans, even the cans placed near the middle,
Since the cool air is sufficiently applied through the gap, it is cooled for a relatively short time. Furthermore, since the deformed seamless can has the thick portion at or near the boundary between the upper portion and the lower portion of the can body portion, it is possible to improve the compressive strength in the can body height direction.

The method for producing a modified seamless can of the present invention is
First, after ironing a metal cup with a punch having a reduced diameter portion to produce an ironing can body in which a thick portion corresponding to the reduced diameter portion is formed, the lower part of the ironing can body is bottomed from the bottom side. The step of pushing a predetermined depth into a diameter-reducing die having a hole smaller than the outer diameter of the body is performed at least once to reduce the diameter to form a reduced diameter lower portion. By appropriately determining the number of steps in this case according to the thickness and hardness of the can body of the ironing can body, the type of tool, etc., it is possible to form the lower part without causing wrinkles on steps or the like. it can. Next, the diameter-reduced lower part is expanded and molded into an inverted truncated cone shape. In this case, the diameter-reduction die is formed so that a thick part is formed at least at or near the boundary between the upper part and the lower part. Adjust the depth to press into. Generally, due to the above diameter reduction, the step portion is considered to be due to the Bauschinger effect, but since it is softer than before the diameter reduction, cracks are unlikely to occur in the step portion when expansion-molding into an inverted truncated cone shape. In the modified seamless can of the present invention, since the thick portion is formed in the portion that forms the step portion, cracking is less likely to occur.

The method for producing a modified seamless can of the present invention is
Since the rigid punch is pushed into the ironing can body having the reduced diameter lower portion formed therein to expand the reduced diameter lower portion, wrinkles are less likely to occur during formation of the lower portion. Further, since a rigid punch is used, there is an advantage that the life of the punch is long. Further, the method for producing a modified seamless can of the present invention is such that a die having a cavity of an inverted truncated cone shape is inserted with a reduced diameter lower portion, and elastic pressure or fluid pressure is applied to the lower portion to lower the lower portion. Therefore, as described above, there is an advantage that wrinkles are less likely to occur when the lower portion is formed. Further, since elastic pressure or fluid pressure is applied to the lower portion by a punch made of, for example, elastic rubber, and the lower portion is expanded into an inverted truncated cone shape, there is an advantage that the inner surface organic coating is less likely to be damaged by friction.

FIG. 1 is a vertical cross-sectional view of a modified seamless can according to the first embodiment of the present invention. The modified seamless can 1 according to the embodiment of the present invention shown in FIG.
And a smooth neck-in portion 3, a flange portion 4, and a bottom portion 5. The can body portion 2 is composed of an upper portion 2a formed of a cylindrical portion and a lower portion 2b. The lower portion 2b has an inverted frustoconical shape in which the outer diameter of the upper end portion 2b1 is equal to the outer diameter of the upper portion 2a, and the bottom portion 5, the outer diameter is gradually reduced with a relatively gentle gradient, and its lower end 2b2 has a short cylindrical shape. The upper end 2b1 of the lower portion 2b is preferably located below the height of the can 1 in the height direction, which is about half in view of the stability of the can, but is not particularly limited in the present invention.

Further, the modified seamless can 1 of the present invention is
A thick wall portion 2f is provided at or near a boundary portion 2c between the upper portion 2a and the lower portion 2b of the can body portion 2.

The number of bands of the thick portion 2f formed in the inner circumferential direction of the can body portion 2 may be one or plural. In the embodiment shown in FIG. 1, the thick portion 2f is formed at a set position from the lower end 2a1 of the upper portion 2a to the lower portion 2b.

The thickness of the thick portion 2f is preferably 1.1 to 3 times the thickness of the other portion of the can body portion 2. This is because if the thickness is less than 1.1 times, the strength is not improved, and if the thickness is more than 3 times, punch punching property during DI processing and formation of a step portion described later are hindered. Figure 2
[Fig. 3] is a schematic view of a cross section of a can body showing an embodiment of a modified seamless can of the present invention, and (a) to (g) show different setting positions of the thick part in each modified seamless can. Is. In these figures, for the sake of convenience, the positions of the connecting portions of the upper portion and the lower portion are all the same and are shown by a chain line. In addition, the thickness ratio is exaggerated from the actual thickness so that the thick portion and other portions can be easily distinguished. Figure 2
The form (a) is particularly effective for suppressing the buckling of the lower portion of the deformable seamless can due to the axial load when the lid is wound when the lower portion is set to have a longer length than the upper portion. effective. The configuration of FIG. 2B is particularly effective in suppressing the buckling of the upper portion of the deformable seamless can due to the axial load when the length of the upper portion is set longer than that of the lower portion. The configuration of FIG. 2C is particularly effective in suppressing the buckling of the boundary portion due to the axial load when the radius of curvature of the boundary portion between the upper portion and the lower portion of the deformable seamless can is relatively large. In the configuration of FIG. 2D, the can body is paneling deformed under negative pressure when the length of the lower part of the deformed seamless can is set longer than that of the upper part or the lower part has a polygonal truncated pyramid shape. It is particularly effective in suppressing this. In the configuration of FIG. 2 (e), the can is paneled and deformed under negative pressure when the length of the upper part of the deformed seamless can is set longer than that of the lower part or the upper part has a polygonal tubular shape. It is especially effective in suppressing In the configuration of FIG. 2 (f), the length of the lower portion of the modified seamless can is set longer than that of the upper portion, or the lower portion has a polygonal truncated pyramid shape, and the boundary portion between the upper portion and the lower portion is further increased. When the radius of curvature of is set to be large, it is particularly effective in suppressing the paneling deformation of the can under negative pressure. In the form of FIG. 2 (g), the length of the upper part of the deformed seamless can is set longer than that of the lower part, or the upper part has a polygonal tubular shape, and the boundary between the upper part and the lower part is further increased. When the radius of curvature of is set to be large, it is particularly effective in suppressing the paneling deformation of the can under negative pressure. As described above, the conditions that are particularly effective for the setting method of the various thick portions are shown, but the thick portions can be set without being limited to this condition.

Although not shown, the neck-in portion 3 may be a multi-stage neck-in portion. Lower part upper end 2b1
May be in an appropriate position depending on the application of the can,
Considering the stability of the can, it is preferable that the deformed seamless can 1 is positioned at about ½ or less from the bottom with respect to the total height, but it is preferably determined depending on the application. Further, the bottom portion 5 is provided with a chime portion 5a, a ground contact portion 5b formed of a curved portion, an inner wall portion 5c rising slightly inward of the ground contact portion 5b, and a dome-shaped central panel portion 5d, which is resistant to buckling. Are better.

The outer diameter of the lower end 2b2 of the lower portion 2b is such that the cans produced from the modified seamless can 1 can be stacked on top of each other, that is, the contents 7
After filling the can, the can lid 6 is double-wound, and the neck of the can (the double-wound portion is not shown) can be placed on the double-wound portion of the can. It is desirable that the inner diameter is approximately equal to the inner diameter of the neck portion 3a of the in portion 3. The intersecting portion 8 between the lower end 2b2 and the chime portion 5a slightly protrudes, as will be described later, when the lower portion 2b is formed, and may not be protruded depending on the condition for forming the lower portion 2b. it can.

Next, an embodiment of a method of manufacturing the modified seamless can 1 will be described. FIG. 3 is a schematic cross-sectional view of the ironing can body 11 in which a thick portion 12f is formed in the inner center portion of the can body portion 12 of the ironing can body 11. The ironing can body 11 has a bottom portion 15 including a chime portion 15a curved inward, a ground portion 15b, and a dome-shaped central panel 15c. The chime portion 15a is connected to the can body portion 12 via the curvature portion 13. The wall thickness of the open end 12d of the can body 12 including the neck-in portion 3 and the flange portion 4 of the deformed seamless can 1 is appropriately determined from the relationship with the neck-in molding method and the can lid used. It It is desirable that the outer surface of the can body portion 12 be printed in advance by a conventional method. FIG. 4 and FIG. 5 are schematic explanatory views for manufacturing the ironing can body 11. As shown in FIGS. 4 and 5, the manufacturing of the ironing can body 11 is carried out by first using the metal cup 501.
Then, the ironing can body 11 is formed by ironing processing or the like. The wrinkle holding ring 503 presses the peripheral portion of the bottom of the metal cup 501 against the redrawing die 504 to hold it down to prevent wrinkling of the ironing can body 11 during processing. The clearance between the ironing punch 502 and the ironing die 505 is set to be the wall thickness of the can body of the modified seamless can 1. Reduced diameter part (recess) 5
At the stage of ironing the metal cup 501 by using the ironing punch 502 having 06 in the circumferential direction, the ironing can body 11 in which the thick portion 12f is formed at the location corresponding to the reduced diameter portion 506 is produced. It

The reduced diameter portion (recess) 506 formed on the ironing punch 502 has chamfered portions 506 above and below it.
It is preferable to form a and 506b. By forming the chamfered portions 506a and 506b, it becomes easy to remove the ironing can body 11 from the ironing punch 502. In this way, the thick portion 12f is provided in the middle of the can body portion 12.
The ironing can body 11 having the is formed. Generally, the metal cup 501 is preferably lubricated during the ironing process, but can be processed without lubrication when the resin-coated metal plate is used as a blank. It should be noted that FIGS. 4 and 5 show a method of starting the ironing process from a metal cup 501 using a two-stage stacking die including a redrawing die 504 and an ironing die 505. It is also possible to directly form the ironing can body 11 by.

Next, description will be made with reference to FIGS. 3 and 6 to 12. FIG. 6 is a vertical sectional view showing a state where a punch is inserted in the ironing can body of FIG. FIG. 7 is a vertical cross-sectional view showing a state immediately after a one-step ironing can body having a lower cylindrical portion is formed from the ironing can body of FIG. 6. FIG. 8 is a vertical cross-sectional view showing a state where the punch is pulled out from the ironing can body of FIG. 7. 9 is a vertical cross-sectional view showing a state where the ironing can body of FIG. 8 is pushed up. FIG. 10 is a longitudinal sectional view showing a state in which the one-step reduced diameter can body is placed on the die and the punch is inserted to form the two-step reduced diameter can body from the one-step reduced diameter can body of FIG. 9. is there.
FIG. 11 is a vertical cross-sectional view showing a state immediately after the two-step reduced diameter can body is formed from the one-step reduced diameter can body of FIG. 10. Figure 1
2 is a drawing showing a first embodiment for forming a plain can of the deformed seamless can of FIG. 1 from a three-step reduced diameter can body, in which the three-step reduced diameter can body is placed on a bed. It is a longitudinal cross-sectional view showing a state. First, as shown in FIG. 3, the lower portion of the ironing can body 11 is reduced in diameter by a diameter-reducing die 21 having a hole 22 having a diameter smaller than the outer diameter of the ironing can body 11, and then the reduced downside. The portion 12c is expanded and formed into an inverted truncated cone shape. In this case, at least the upper part 12b and the lower part 12
Diameter reduction processing is performed so that the thick portion 12f is located at or near the boundary with c. The die device 20 for reducing the diameter includes a reducing die 21 having a hole portion 22 and a knockout plate 25. The diameter reducing die 21 is
It is fixed to the die plate 23 by a support 24.
The knockout plate 25 is configured to be vertically moved at an appropriate timing by a drive device (not shown), such as an air cylinder, via a shaft 25 that passes through the through hole 23a of the die plate 23.

The inner peripheral surface of the hole 22 has a shape corresponding to the lower end 12a of the can body portion and the curved portion 13 in the vicinity of the curved portion 13 of the ironing can body 11, that is, the lower end 12a of the can body portion and the curved portion 13 are almost exactly the same. A seat portion 22a that can be seated, a working surface 22b that is connected to the lower end of the seat portion 22a and hangs down, and a flank surface 22c that extends obliquely downward and outward. The inner diameter of the action surface 22b is set equal to the outer diameter of the lower portion of the can body portion 12 to be reduced in diameter (see the reduced diameter portion 40a in FIG. 9).

Further, as shown in FIG. 6, the diameter reducing punch device 28 is provided with a punch support 30 attached to a punch plate 29, a bolt 31 and a punch 32 screwed to the punch support 30. There is. The punch plate 29 is driven by a drive mechanism (not shown: crank mechanism, for example).
It is capable of reciprocating (up and down movement in the case shown) with a predetermined stroke length. The punch support 30 has a main portion 30a and a short cylindrical lower projection 30c connected to the main portion 30a via a step portion 30b extending in the radial direction. The diameter of the lower protrusion 30c is set to a size that allows the lower protrusion 30c to be loosely inserted into the relatively thick open end 12b of the ironing can body 11. Further, the side surface 30c1 of the lower protrusion and the step portion 30b intersect at a right angle in cross section. The punch 32 is provided with an upper hole portion 32a through which the bolt 31 is inserted and a lower hole portion 32b which is connected to the upper hole portion 32a through a step portion 32b1. As shown in the drawing, the punch 32 is always provided on the upper surface 31a1 of the bolt head 31a. The step 32b1 is engaged, and the punch 32 is suspended slightly away from the support tool 30, that is, forming the gap 26.

The diameter of the upper end portion 33a of the can body portion 33 of the punch 32 is set so that it can be loosely inserted into the open end portion 12d of the ironing can body 11. The diameter of the main body portion 33b of the can body portion below the upper end portion 33a is equal to
It is set to be smaller than the inner diameter of 2b by 2 × (1.1 to 1.5) × t (t is the thickness of the portion of the ironing can body 11 whose diameter is reduced). The portion corresponding to the thick portion 12f is set smaller than this. Bottom 34 of punch 32
Is a curved portion 34a connected to the lower end of the can body main portion 33b,
A step portion 34 extending radially inward from the end of the curvature portion 34a
b, an annular protrusion 34c connected to the inner end of the step portion 34b, and an inner peripheral surface located inside the annular protrusion 34c and communicating with the lower hole portion 32b is provided with a recessed portion 34d having a short cylindrical shape. When the punch 32 is inserted into the ironing can body 11, as shown in FIG. 6, the bottom curved portion 34a and the bottom surface of the annular protrusion 34c respectively correspond to the inner surface near the upper end of the chime portion 15a of the ironing can body 11 and the grounding portion 15b. The height h1 of the gap 26 contacting the inner surface is such that the can body end face 12d of the ironing can body 11
The dimension of each part is determined so that it is larger than the height h2 between the inner end 30b1 of the step portion 30b of the support and the inner end 30b1. The punch support 30 and the punch 32 are formed with an air blow-out guide hole 35 that is connectable via a gap 26 and is connected to a pressurized air source (not shown).

The above die device 20 and punch device 28
Thus, the reduced diameter can body 40 having one step (hereinafter referred to as a one-step reduced diameter can body: see FIG. 9) is formed as follows. As shown in FIG. 3, the ironing can body 11 is placed on the sheet portion 22 a of the hole 22 of the diameter reducing die 21. At this point, the punch 32 of the punch device 28 has the ironing can body 11
Is located directly above the can body portion end surface 12d at a height at least approximately twice the height of the can. In this state, as shown in FIG. 6, the punch plate 29 descends and the annular projection 34c of the punch comes into contact with the inner surface of the grounding portion 15b of the ironing can body 11. When it continues to descend, as shown in Fig. 7,
The can body end face 12d of the ironing can body 11 abuts the inner end 30b1 of the step of the punch support, and the lower part 12c of the ironing can body 11 descends while the diameter decreases by the action surface 22b of the die 21. As a result, the reduced diameter portion 40a and the step 40b having a shape corresponding to the sheet portion 22a of the reduced diameter die 21 are formed.
When the height h of the reduced diameter portion 40a reaches almost the center height of the portion of the ironing can body 11 where the thick portion 12f is formed in the can body portion, the punch plate 29 moves to the bottom dead center. After that, the punch 32 rises and comes out of the one-step reduced diameter can body 40 in which the reduced diameter portion 40a and the step 40b are formed (see FIG. 8). Immediately, the knockout plate 25 rises and pushes up the one-step diameter reduction can body 40 above the diameter reduction die 21 (see FIG. 9).

FIGS. 10 and 11 show the main part of the process of forming the two-step reduced diameter can body 41 from the one-step reduced diameter can body 40. 1
The main difference between the tool used and the case of forming the step-reduced can body 40 is that the punch support 37a of the punch device 37 is used.
Lower projection 37a1 (corresponding to 30c in FIG. 6) of the one-step diameter reducing can body 40 is long enough not to contact the step portion 37c (FIG. 11). The radius of curvature of the bottom curvature portion 37a2 of the protrusion 37a1 is the step 40b.
The inner diameter of the can body of the punch 37b is substantially equal to the inner diameter of the reduced diameter portion 41a of the two-step reduced diameter can body 41 to be formed over the entire height, and the lower projection 3
A plurality of coil springs 39 having a small spring constant are provided at equal intervals between 7a and the punch 37b,
For example, the inner diameter of the working surface 38a of the die 38 is equal to the outer diameter of the reduced diameter portion 41a of the two-step reduced diameter can body 41. Lower protrusion 3
The diameter of 7a1 is set to a size such that it can be loosely inserted into the upper portion 40c of the one-step reduced diameter can body 40. The plurality of coil springs 39 are for correctly positioning the punch 37b during molding, and do not function as a pressing cushion.

The two-step reduced diameter can body 41 is formed as follows. That is, as shown in FIG. 10, the one-step reduced diameter can body 40 is seated on the seat portion 38a of the die 38 (the cross-sectional shape is substantially the same as the seat portion 22a of FIG. 6, but the inner diameter is different), and then the punch 37b and the lower protrusion 37a1 are respectively provided on the reduced diameter portion 40a and the upper portion 4 of the reduced diameter can body 40.
Insert at 0c. When the punch device 37 is lowered, the coil spring 39 is weak, so that the punch 37b remains in the position shown in FIG. 10 and only the lower protrusion 37a1 descends so that the bottom curvature portion 37a2 contacts the step 40b.

When the punch device 37 is further lowered, the step portion 40b is pressed by the bottom curvature portion 37a2, while the reduced diameter portion 40a is pressed against the side wall of the punch 37b by the working surface 38a of the die 38 and contracted. The diameter is reduced to form the reduced diameter portion 41a. The lowering of the punch device 37 is stopped just before the bottom curvature portion 37a2 contacts the upper corner 38a1 of the seat portion 38 via the step 40b (FIG. 1).
1). At this point, the second step 41b is formed, and the two-step reduced diameter can body 41 is formed. The subsequent operation is the same as in the case of forming the one-step reduced-diameter can body 40. Then, the two-step diameter-reduced can body 41 is changed to a step 42b using the same device except that the inner diameter of the working surface and the diameter of the punch are smaller.
3-step reduced diameter can body 42 having 1, 42b2 and 42b3
(FIG. 12). The reason why there are three steps in the above method is that the upper surface of the step during molding is free, and therefore, if the radial width of each step is increased, wrinkles are likely to occur in the step. Therefore, when the difference in diameter between the upper part 1'a and the lower part 1'b of the bottom of the can 1 '(see FIG. 16) described later is relatively small, or the can body of the ironing can body 11 is relatively thick and soft. In cases such as where wrinkles are unlikely to occur, the number of steps may be one or two. If necessary, four or more steps may be formed. Further, where two or more steps are formed, the steps may be smoothly connected to each other in a tapered shape so that the steps are not formed. If there are multiple steps,
It is preferable that all the steps are formed in the thick portion 12f in consideration of the improvement of the buckling strength of the deformed seamless can 1, but in the present invention, at least one of the steps is formed. If formed, it will improve the buckling strength.

Next, referring to FIGS. 13 to 16, the lower portion of the three-step reduced diameter can body 42 is expansion-molded to form the deformed seamless can 1.
The step of forming the can 1'of will be described. FIG.
FIG. 13 is a vertical cross-sectional view showing a state immediately before the lower portion of the reduced diameter can body of FIG. 12 is opened with a punch. FIG. 14 is a longitudinal sectional view showing a state where the reduced diameter can body of FIG. 12 is being expanded with a punch. FIG. 15 is a vertical cross-sectional view showing a state immediately after the unsealing of the reduced-diameter can body of FIG. 12 is completed and a blank can is formed. 16
FIG. 16 is a vertical cross-sectional view showing a state immediately after the punch is extracted from the bare can of FIG. 15. As shown in FIG. 12, the bed 50 has
The short cylindrical portion 51 having a shape corresponding to the vicinity of the bottom portion 45 including the lower end portion 42a1 of the reduced diameter portion 42a of the reduced diameter can body 42.
a and a concave portion 51 having a peripheral surface composed of a curved portion 51b slightly convex toward the inside which is connected to the short cylindrical portion 51a via a sharp corner 51c. The inner diameter of the short cylindrical portion 51a is set so that the lower end portion 42a1 of the reduced diameter portion can be loosely inserted, that is, there is a slight gap between the short cylindrical portion 51a and the lower end portion 42a1. Figure 10
As shown in FIG. 5, a rigid punch 52 fixed to a punch plate 53 that can be moved up and down at a predetermined timing and stroke length by a drive mechanism (not shown) (for example, tool material such as tool steel, cemented carbide, or ceramics). The outer peripheral surface of (comprising) is substantially corresponding to the inner surface of the can body 2 of the deformed seamless can 1 to be formed. That is, the punch 52 has a cylindrical cylindrical portion 52a having a diameter substantially equal to the inner diameter of the open end portion 42c of the three-step reduced diameter can body 42.
The taper portion 52b has a shape of an inverted truncated cone that gradually becomes thinner toward the bottom portion 52c. The diameter of the lower end 52b1 of the taper portion 52b is equal to the inner diameter of the reduced diameter portion 42a of the three-step reduced diameter can body 42. The bottom 52c of the punch 52 is formed with a short cylindrical recess 52c1 communicating with an air blowing guide hole 54 connected to a pressurized air source (not shown). This is to accommodate the central panel 45b at the end of molding (FIG. 15). In addition, the tapered portion 52 of the punch 52
If b has an inverted polygonal truncated pyramid shape instead of the inverted truncated cone shape, the base can 1'of the deformed seamless can 1 follows this shape.
The lower part of can be shaped like an inverted polygonal frustum. Alternatively, if the cylindrical portion 52a of the punch 52 has a polygonal columnar shape, the upper portion of the plain can 1'of the deformed seamless can 1 can be formed into a polygonal tubular shape.

The modified seamless can 1 is formed as follows using the bed 50 and punch 52 described above. The three-step reduced-diameter can body 42 is inserted and placed in the recess 51 of the bed (FIG. 12), and the rigid punch 52 together with the punch plate 53.
Is lowered and pushed into the 3-step reduced diameter can body 42. Punch 5
After the lower end 52b1 of the second tapered portion 52b contacts the reduced diameter portion 42a of the three-step reduced diameter can body 42 (FIG. 13), the reduced diameter portion 42a is spread from above by the tapered portion 52b as the punch descends. Steps 42b3, 42b2 and 42b1
Disappear in sequence (Fig. 14). Then, as shown in FIG. 15, the bottom surface 52c2 of the punch is the upper surface 50a of the bed 50.
When the punch 52 reaches the bottom dead center and the upper portion 1'a has a cylindrical shape and the lower portion 1'b has an inverted frustoconical shape, the punch 1'of the deformed seamless can 1 is reached. Is formed. The lower end 1'b1 (corresponding to the intersecting portion 8 of the deformed seamless can 1; see FIGS. 1 and 16) of the lower portion of the bare can 1'is slightly projected because of the short cylindrical portion 51a and the lower end 42a1.
This is because there is a slight gap between the two (FIG. 12) and the lower end 1'b1 is slightly expanded during molding.

Next, the pressurized air 5 is supplied from the air blowing introduction hole 54.
Punch 5 while raising 5 while blowing 5.
2 is pulled out from the can 1 '(FIG. 16). After that, can 1 '
Is taken out of the bed 50 and the open end 1'of a relatively thick wall
The modified seamless can 1 having the neck-in portion 3 and the flange portion 4 is manufactured by subjecting a1 to the neck-in processing and the flange processing by a conventional method. The diameter of the ground portion 5b of the modified seamless can 1 is the same as the diameter of the ground portion 15b of the ironing can body 11.

Next, referring to FIGS. 17 to 21, a diameter-reduced can body 56 having one step, the outer diameter of the diameter-reduced portion of the ironing can body 11 being equal to that of the three-step diameter-reduction can body 42. An embodiment in which (hereinafter, referred to as a one-step reduced diameter can body 56: see FIG. 21) is formed without causing wrinkles on the step will be described. FIG. 17
Is used in the embodiment for forming the one-step reduced diameter can body having the lower cylindrical portion reduced in diameter to the same diameter as the three-step reduced diameter can body of FIG. 12 in order to manufacture the modified seamless can of FIG. It is a longitudinal cross-sectional view of a punch device. 18 is a vertical cross-sectional view showing a state in which the wrinkle retainer of the punch device of FIG. 17 is inserted into an ironing can body placed on a die. FIG. 19 shows FIG.
FIG. 8 is a vertical cross-sectional view showing a state immediately after a punch is pressed into the ironing can body of No. 8 and a one-step reduced diameter can body is formed. Figure 20
FIG. 20 is a vertical cross-sectional view showing a state where the punch device is pulled out from the one-step reduced-diameter can body in FIG. 19. FIG. 21 is a vertical cross-sectional view showing a state where the one-step reduced diameter can body of FIG. 19 is pushed up onto the die. First, FIG. 17 shows a punch device 60 used in this case. The punch device 60 includes a punch 62 fixed to a punch plate 61 and a wrinkle retainer 6
3 and a wrinkle holding plate 64. The wrinkle retainer 63 is inserted through the through hole 64a of the wrinkle retainer plate 64 and is normally suspended as shown by a plurality of bolts 65 screwed to the flange portion 63a. A coil spring 66 for cushioning is provided between the flange portion 63a and the wrinkle holding plate 64 so as to surround the bolt 65. Between the punch 62 and the wrinkle retainer 63, a gap portion 67 having a slight gap width that does not interfere with each other is provided. The diameter of the wrinkle retainer 63 is set to a size such that it can be loosely inserted into the open end 12b of the ironing can body 11. The bottom portion 68 of the punch 62 includes a curved portion 68a connected to the lower end of the side wall portion 62a, a step portion 68b extending radially inward from the end of the curved portion 68a, an annular protrusion 68c and an annular protrusion connected to the inner end of the step portion 68b. The inner peripheral surface located inside 68c is provided with a concave portion 68d having a short cylindrical shape.

As shown in FIG. 18, below the punch device 60, as compared with the die device 20 shown in FIG. 3, the inner diameter of the working surface 44b is equal to that of the reduced diameter portion 56a of the one-step reduced diameter can body 56. A die unit 46 is provided which is similar except that it comprises a diameter reducing die 43 which is equal to the outer diameter and, correspondingly, the radial width of the seat portion 44a is larger than that of the seat portion 22a. The lower end surface 63b of the wrinkle retainer 63 has a shape corresponding to the sheet portion 44a of the diameter reducing die 43. The inner diameter of the inner peripheral surface 63c of the wrinkle retainer 63 is set to be substantially equal to the inner diameter of the working surface 44b of the diameter reducing die 43. Further, the diameter of the punch 62 is smaller than the inner diameter of the working surface 44b of the diameter reducing die 43 by 2 × (1.1 to 1.5) × t (t is the thickness of the reduced diameter portion of the ironing can body 11). It is set. The portion corresponding to the thick portion 12f is set smaller than this. As shown in FIG. 19, with the punch 62 being pushed into the ironing can body 11, the bottom annular protrusion 68c
The size and shape of the punch 62 are determined so that the bottom surface of the punch contacts the inner surface of the grounding portion 15b of the ironing can body 11. The punch 62 is formed with an air blowing guide hole 69 that is connected to a pressurized air source (not shown) and reaches the recess 68d.

The die device 46 and punch device 60 described above
Thus, the one-step reduced diameter can body 56 is formed as follows. The ironing can body 11 is placed on the sheet portion 44a of the hole portion 44 of the diameter reduction die 43 (this state is not shown) in the same manner as when forming the one-step diameter reduction can body 40.
At this point, the punch 62 and the wrinkle retainer 63 of the punch device 60 are located right above the ironing can body 11 at a height at which the distance from the end face of the can body portion is at least about twice the can height.
In this state, as shown in FIG. 18, the wrinkle holding plate 64
And at the same time, the wrinkle retainer 63 descends, and its lower end surface 63b elastically lowers the pressing spring 66 and presses substantially the upper half of the curvature portion 13 and the chime portion 15a of the ironing can 11.

The punch plate 61 immediately descends, and as shown in FIG. 19, the annular projection 68c of the punch comes into contact with the inner surface of the grounding portion 15b of the ironing can body 11, and the lower portion 12c of the ironing can body 11 has a reduced diameter. By the action surface 44b of the die 43, the diameter is reduced by being pressed by the wrinkle retainer 63 and reduced in diameter, and a step difference diameter 56b having a step 56b having a shape corresponding to the sheet portion 44a of the diameter reduction die 43 is formed. The can body 56 is formed. When the height of the reduced diameter portion 56a reaches approximately the middle of the width of the thick portion 2f formed in the can body of the ironing can body 11, the punch plate 61 reaches the bottom dead center, and air is blown thereafter. The pressurized air 70 is blown out from the guide hole 69 and rises, and the punch 62 comes out of the one-step reduced diameter can body 56,
Then, the wrinkle retainer 63 and the wrinkle retainer plate 64 rise out of the one-step reduced-diameter can body 56 (FIG. 20). Immediately, the knockout plate 59 rises to push up the one-step diameter reducing can body 56 from the diameter reducing die 43 (FIG. 21).

Next, with reference to FIGS. 22 to 28, there will be described an embodiment in which a base can 1'of a deformed seamless can 1 is formed from a three-step reduced diameter can body using an elastic punch. 22 is a view showing a second embodiment for forming a base can of the deformed seamless can of FIG. 1 from a three-step reduced diameter can body. The three-step reduced diameter can body is placed on a die. It is a longitudinal cross-sectional view showing a state. 23 is a vertical cross-sectional view of a punch for forming the raw can of the modified seamless can of FIG. 1 in cooperation with the die of FIG. FIG. 24 is a vertical cross-sectional view showing an initial state in which a punch is inserted into the three-step reduced diameter can body shown in FIG. FIG. 25 shows
FIG. 23 is a vertical cross-sectional view showing a state where a punch is pressed into the three-step reduced diameter can body shown in FIG. 22. FIG. 26 is a longitudinal sectional view showing a state immediately after the base can of the modified seamless can of FIG. 1 is formed from the three-step reduced diameter can body of FIG. 22. FIG. 27 is a vertical cross-sectional view showing a state in which the punch is extracted from the bare can of FIG. 28 is a vertical cross-sectional view showing a state where the blank can of FIG. 27 is pushed up from the die. First, referring to FIG. 22, the die device 71 includes a die 73 fixed to the bed 72 and a bed 7
The second concave portion 75 and the knockout plate 74 that can move up and down in the cavity 73a of the die 73 are provided.
The peripheral surface 73a1 of the cavity 73 has a truncated cone shape corresponding to the lower truncated cone-shaped lower portion 1'b (see FIG. 16) of the blank can 1'to be formed. The inner peripheral surface of the recess 75 is
3 stepped diameter reducing can body 42 of the reduced diameter portion 42a of the lower end portion 42a1 of the short cylindrical surface portion 75a of the inner diameter equal to the outer diameter, the chime portion 42
It comprises a curved portion 75b having a shape corresponding to the upper portion of a2 and a short cylindrical surface portion 75c hanging from the lower end of the curved portion 75b. The knockout plate 74 is formed with an annular cutout portion having an L-shaped cross section, which is composed of a horizontal portion 74a and a hanging portion 74b along the upper surface rim. Knockout plate 7
4 is always in contact with the bottom surface 75d of the recessed portion 75, and the horizontal portion 74a is in contact with the ground portion (deformation) of the reduced diameter can body 42 while the chime portion 42a2 at the bottom of the reduced diameter can body 42 is seated on the bed 72. Corresponding to 5b of seamless can 1), hanging part 74
Is dimensioned so as to contact the inner wall portion (corresponding to 5c of the deformed seamless can 1).

As shown in FIG. 23, the punch plate 77 is used.
The punch 76 fixed to the main part is mainly composed of a rigid portion 78 (made of, for example, tool steel or the like) in the upper portion, and a hollow elastic portion 79 (made of, for example, elastic rubber or elastic plastic) in the lower portion. The outer diameter of the rigid body portion 78 is set to be substantially equal to the inner diameter of the open end portion 1′a1 (FIG. 16) of the base can 1 ′. The outer surface of the elastic portion 79 has a cylindrical portion 79a at the top,
Inverted frustoconical portion 79b whose lower portion extends slightly inward and downward
It has become. The hollow portion 81 has the enlarged diameter portion 80a at the lower end.
And a central shaft 80 screwed to the rigid body portion 78 through
The elastic portion 79 is fixed to the rigid body portion 78. Central axis 80
Further, the rigid body portion 78 is formed with an air blowing guide hole 82 communicating with a pressurized air source (not shown). Expanded part 8
A concave portion 80a1 is formed on the lower surface of 0a. The height from the bottom surface of the central shaft 80 to the upper surface of the elastic portion 79 is set to be slightly higher than the height of the lower portion 1′b of the bare can to be formed.

Using the die device 71 and the punch 76 described above, the blank can 1'is formed from the three-step reduced diameter can body 42 as follows. Die cavity 73a and bed 7
After the three-step reduced diameter can body 42 is inserted and placed in the second concave portion 75 (FIG. 22), the punch plate 77 is lowered and the punch 76 is moved to 3 as shown in FIGS. 24, 25 and 26.
Step-reduced can body 42 (not shown, one step-reduced can body 5
6 may be used). The diameter reduction can body 42 is hardly deformed until the lower end of the elastic portion 79 contacts the upper step 42b1 (FIG. 24), but when the punch 76 further descends, the upper step 42b1, the intermediate step 42b2, and the lower step 42b2. The step 42b3 is pressed against the cavity peripheral surface 73a1 of the die 73 by the elastic portion 79 and disappears (FIG. 25), and the reduced diameter portion 42a is sequentially pressed from the upper side to the peripheral surface 73a1 to expand to form an inverted truncated cone shape. A bare can 1'having a lower part 1'b is formed (Fig. 26). At this time, the central panel (corresponding to 5d of the deformed seamless can 1) enters the recess 80a1. Immediately while the pressurized air 83 is being blown out from the air blowing guide hole 82, the punch 76 is raised and pulled out from the raw can 1 '(FIG. 27). Next, the knockout plate 74 is raised to push up the can 1'from the diameter reducing die 73 (see FIG. 2).
8). If the peripheral surface 73a1 of the cavity 73 has an inverted polygonal truncated cone shape instead of the inverted truncated cone shape, the lower portion of the base can 1'of the modified seamless can 1 has an inverted polygonal truncated cone shape. It can be molded.

Next, another embodiment of the present invention will be described with reference to FIGS. FIG. 29 is a vertical cross-sectional view of a modified seamless can according to the second embodiment of the present invention.
30 is a vertical cross-sectional view of an ironing can body used to form the modified seamless can of FIG. FIG. 31 is a vertical cross-sectional view of a modified seamless can according to the third embodiment of the present invention. FIG. 32 is a vertical sectional view of a modified seamless can according to the fourth embodiment of the present invention. FIG. 33 corresponds to FIG.
FIG. 3 is a vertical cross-sectional view of an ironing can body used to form the modified seamless can of FIG. First, as shown in FIG. 29, the modified seamless can of the present invention has a central panel 10 of the bottom portion 105.
5d may be a deformed seamless can 105 for negative pressure canning, which is flat. In this case, accurate internal pressure (negative pressure) measurement is easy by vibrating the panel unit 105d with a percussion instrument (not shown). Deformed seamless can 1
01 is the same as the squeezing can body 11 except that the central panel 111d at the bottom is flat (Fig. 3).
0) is manufactured in the same manner as the modified seamless can 1. Further, as shown in FIG. 31, the lower portion 202b of the can body portion
The deformed seamless can 201 may be the same as the deformed seamless can 101 except that is slightly curved inward. The modified seamless can 201 is particularly suitable for use in negative pressure canned products having an internal pressure lower than atmospheric pressure, such as coffee drink cans. Of course, it can also be applied to positive pressure cans. The modified seamless can 201 has a cavity peripheral surface (73a1; see FIG. 22) of a die (73) used when forming a plain can, and a lower part 2
The modified seamless can 101 is manufactured in the same manner as the deformed seamless can 101 except that the shape corresponds to 02b.

Further, as shown in FIG. 32, the bottom annular protrusion 301b is a simple curved portion without the chime portion (5a), and the can body 301a and the central panel 301c are directly annular protrusions 301b. It may be a modified seamless can 301 of a type that is connected via. The deformed seamless can 301 is the same as the squeezing can body 311 except that it has an annular protrusion 311a made of a curved portion having a relatively large radius of curvature as shown in FIG. It is manufactured by a method similar to. Further, the neck-in part may be a single-step or multi-step neck-in part. Alternatively, the neck-in portion may be omitted and the flange portion may be directly formed on the upper end of the upper portion 2a. Although not shown, after forming a blank can from the ironing can body having a flat bottom by the above-described method, an annular protrusion and a central panel may be formed on the bottom. In the state of FIG. 22, the three-step reduced diameter can body 4
A fluid pressure (liquid pressure or gas pressure) to the extent that the center panel (5d) at the bottom does not buckle is applied to the inside of 2 to expand the diameter-reduced portion 42a and the steps 42b1, 42b2, 42b3 to expand the can 1 '( 27) may be formed. Similarly, a fluid pressure may be applied to the one-step reduced diameter can body 56 to form the canister 1 ′. Although the upper portion has a cylindrical shape and the lower portion has an inverted truncated cone shape, the upper portion may have a polygonal cylindrical shape and the lower portion may have an inverted polygonal truncated cone shape. Further, the upper part may have a cylindrical shape and the lower part may have an inverted polygonal truncated cone shape, and the upper part may have a polygonal cylindrical shape and the lower part may have an inverted truncated cone shape.

As the material of the blank, various surface-treated steel plates and light metal plates such as aluminum thin plates are used.
As the surface-treated steel sheet, cold rolling, or subsequent annealing, secondary cold rolling, one or more surface treatments such as tin plating, nickel plating, zinc plating, aluminum plating, electrolytic chromic acid treatment, etc. Examples include those performed. Among them, tin-plated steel sheet having a plating amount of 0.5 to 11.2 g / m ² , or 10 to 200 mg /
m ² metal chrome layer and 1-50 mg / m on it
An electrolytic chromic acid-treated steel sheet (tin-free steel) having a chromium oxide layer of ² (in terms of metal chromium) is preferably used. The latter is excellent in work adhesion and corrosion resistance to the organic coating, and is therefore preferably used as an organic coating-coated blank in the case of thin-walled redraw forming. A so-called pure aluminum plate or an aluminum alloy plate is used as the light metal plate. Above all, Mn: 0.1 to 1.5
% By weight, Mg: 0.12-5% by weight, Zn: 0.01-
0.4 wt%, Cu: 0.15-0.45 wt%, S
An aluminum alloy having a composition of i: 0.6% by weight or less, Fe: 0.7% by weight or less, and the balance Al is preferably used because it has excellent corrosion resistance and workability.

The thickness of the blank varies depending on the type of metal, the use of the deformed seamless can, the size, the shape, etc., but is generally 0.1 to 0.5 mm, and the thickness of the surface-treated steel sheet is 0.1 to 0. 3 mm, 0.15 to 0.
4 mm is preferably used. The strength of the blank varies depending on the type of metal plate, thickness, use of deformed seamless can, size, shape, processing method of the ironing can body 11, etc., but in the case of the surface-treated steel plate, it is 33 to 80 kgf / m.
m ² and a light metal plate having a tensile strength of 23 to 42 kgf / mm ² is preferably used. Ironing can 11
Is formed by drawing-ironing (so-called DI molding), the thickness (metal portion) of the can body portion 12 is 0.06 to
It is preferably 0.2 mm. Japanese Patent Laid-Open No. 1-2588
In the case where the ironing can body 11 is formed by using thinning redrawing molding as disclosed in Japanese Patent No. 22, the thickness of the can body 12 is usually 60 to 90% of the thickness of the blank. is there.

It is preferable that both sides of the ironing can body 11 have an organic coating formed at the time of blanking or after the ironing can body 11 is formed. In addition to improving the storage performance as a can, this is a deformed seamless can 1
This is to reduce the frictional resistance between the tool and the ironing can body 11 at the time of forming, to facilitate the forming. Examples of the organic coating film coated at the time of blanking include a coating film made of a thermosetting resin or a thermoplastic resin, or a thermoplastic resin film. The thickness of the coating film (in a dried state) is preferably 2 to 20 μm from the viewpoint of corrosion resistance and workability. In the case of a thermoplastic resin film, it is usually covered by thermal bonding. From the viewpoint of processing adhesion and corrosion resistance, a polyester film having a thickness of 10 to 30 μm formed by unstretching or biaxial stretching is preferably used from the viewpoint of processing adhesion and corrosion resistance. When the organic film is coated after the ironing can body 11 is used, a method generally used for DI cans, that is, spray coating, roller coating, or the like is adopted.

[0040]

[Embodiment] As a blank material, a surface treatment of electrolytic chromic acid treatment is applied, a plate thickness of 0.180 mm, and a tempering degree D.
A resin-coated steel sheet of R-8 tin-free steel was heat-sealed with a polyester film of 25 μm on the side corresponding to the inner surface of the can and 19 μm on the side corresponding to the outer surface of the can. This resin-coated steel plate was punched into a blank having a diameter of 154 mm to prepare a shallow drawn metal cup having a diameter of about 95 mm. Next, this shallow drawn metal cup was thinned and redrawn and ironed twice to form an ironing can body having a diameter of about 66 mm. The diameter of the ironing punch for making the ironing can is about 66 mm, and the diameter of the reduced diameter part (recess) is
A punch diameter of about 30 μm was used. next,
A dome portion was formed on the bottom by a conventional method to prepare an ironing can body having dimensions as shown in FIG. However, the dimensions shown in parentheses are the thickness of the surface-treated steel sheet itself. This ironing can body is subjected to a diameter reduction process to form a deformed seamless can base from a reduced diameter can body having a stepped portion in the thick portion, and the open end is necked in by a conventional method, A predetermined can lid was attached to obtain a modified seamless can. Then, as a result of performing a compression test on the deformed seamless can with a hydraulic compression tester, the load at the time of starting the buckling (buckling load) is 150 kg weight (1471 N), which is a sufficient strength as a canned container. there were. On the other hand, as a result of measuring the buckling strength in the case where a deformed seamless can is created from an ironing can body without forming a thick portion, the load at the time of starting buckling (buckling load) is 105
It weighed 10 kg (10301 N) and was insufficient in strength as a canned container.

[0041]

INDUSTRIAL APPLICABILITY The deformed seamless can of the present invention is used for negative pressure canning, because it is unlikely to cause a defect such as a dent in the body of the can when it is conveyed in close contact with a conveyor in an empty can while vibrating at high speed. Even when used as a can, the can body is unlikely to be dented, and even when several cans are stacked on a refrigerating shelf without a gap, the cans placed near the center can be cooled relatively quickly. Further, since the deformed seamless can of the present invention has a thick portion near the boundary between the upper portion and the lower portion, it is difficult to buckle when a load in the can body height direction is applied, and the shaft at the time of winding is reduced. The taper does not buckle even under load. Also, paneling deformation is difficult even under negative pressure. Furthermore, the nominal can diameter in the upper part is #
About 211 (diameter about 66.2 mm), the internal volume is about 35
In the case of a 0 ml modified seamless can, it is easy to grab the lower part of the lower part by hand, so that there is an advantage that it is easy to drink the content beverage or the like directly from the opening part of the can lid. INDUSTRIAL APPLICABILITY The method for producing a deformed seamless can of the present invention has an effect that a deformed seamless can whose lower part of the can body has an inverted truncated cone shape can be produced without causing buckling, wrinkling, or cracking.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a modified seamless can according to a first embodiment of the present invention.

FIG. 2 is a view showing different setting positions of a thick portion in the modified seamless can of the present invention.

FIG. 3 is a view showing an embodiment in which a three-step seamless can body having a reduced lower cylindrical portion is formed for manufacturing the modified seamless can of FIG. It is a longitudinal cross-sectional view showing a state of being placed on a die.

FIG. 4 is a schematic explanatory view for manufacturing an ironing can body 11.

FIG. 5 is a schematic explanatory diagram for manufacturing an ironing can body 11.

6 is a vertical cross-sectional view showing a state where a punch is inserted in the ironing can body of FIG.

FIG. 7 is a vertical cross-sectional view showing a state immediately after a one-step ironing can body having a lower cylindrical portion is formed from the ironing can body of FIG.

8 is a vertical cross-sectional view showing a state in which a punch is pulled out from the ironing can body of FIG.

9 is a longitudinal sectional view showing a state where the ironing can body of FIG. 8 is pushed up.

10 is a vertical cross-sectional view showing a state in which a one-step reduced diameter can body is placed on a die and a punch is inserted to form a two-step reduced diameter can body from the one-step reduced diameter can body of FIG. 9; is there.

11 is a vertical cross-sectional view showing a state immediately after a two-step reduced diameter can body is formed from the one-step reduced diameter can body of FIG.

FIG. 12 is a view showing a first embodiment for forming a plain can of the deformed seamless can of FIG. 1 from a three-step reduced diameter can body, in which the three-step reduced diameter can body is placed on a bed. It is a longitudinal cross-sectional view showing a state.

13 is a vertical cross-sectional view showing a state immediately before the lower portion of the reduced diameter can body of FIG. 12 is opened with a punch.

14 is a vertical cross-sectional view showing a state where the reduced diameter can body of FIG. 12 is being expanded by a punch.

15 is a vertical cross-sectional view showing a state immediately after a blank can is formed after the expansion of the reduced diameter can body of FIG. 12 is completed.

16 is a vertical cross-sectional view showing a state immediately after the punch is pulled out from the raw can of FIG.

17 is an embodiment of forming a one-step reduced diameter can body having a lower cylindrical portion reduced in diameter to the same diameter as the three-step reduced diameter can body of FIG. 12 in order to manufacture the modified seamless can of FIG. It is a longitudinal cross-sectional view of the punch device used.

18 is a vertical cross-sectional view showing a state in which the wrinkle retainer of the punch device of FIG. 17 is inserted into an ironing can body placed on a die.

FIG. 19: Push the punch into the ironing can body of FIG.
It is a longitudinal cross-sectional view showing a state immediately after the step diameter reduced can body is formed.

20 is a vertical cross-sectional view showing a state where the punch device is pulled out from the one-step reduced diameter can body in FIG.

FIG. 21 is a vertical cross-sectional view showing a state where the one-step reduced diameter can body of FIG. 19 is pushed up onto the die.

22 is a view showing a second embodiment for forming a plain can of the deformed seamless can of FIG. 1 from a three-step reduced diameter can body, in which the three-step reduced diameter can body is placed on a die. It is a longitudinal cross-sectional view showing a state.

23 is a vertical cross-sectional view of a punch for forming the raw can of the modified seamless can of FIG. 1 in cooperation with the die of FIG. 22.

FIG. 24 is a vertical cross-sectional view showing an initial state in which a punch is inserted into the three-step reduced diameter can body shown in FIG. 22.

FIG. 25 is a vertical cross-sectional view showing a state where a punch is pushed into the three-step reduced-diameter can body shown in FIG. 22.

FIG. 26 is a vertical cross-sectional view showing a state immediately after the plain can of the modified seamless can of FIG. 1 is formed from the three-step reduced diameter can body of FIG. 22.

27 is a vertical cross-sectional view showing a state where a punch is extracted from the bare can of FIG.

28 is a vertical cross-sectional view showing a state where the blank can of FIG. 27 is pushed up from a die.

FIG. 29 is a vertical cross-sectional view of a modified seamless can according to the second embodiment of the present invention.

30 is a vertical cross-sectional view of an ironing can body used to form the modified seamless can of FIG.

FIG. 31 is a vertical cross-sectional view of a modified seamless can according to a third embodiment of the present invention.

FIG. 32 is a vertical sectional view of a modified seamless can according to a fourth embodiment of the present invention.

FIG. 33 is a vertical cross-sectional view of an ironing can body used to form the modified seamless can of FIG. 32.

FIG. 34 is a vertical cross-sectional view showing the schematic dimensions of the ironing can body of the embodiment of the present invention.

[Explanation of symbols]

1: Deformed seamless can 2: Can body 2a: upper part 2a1: the lower end of the upper part 2a 2b: lower part 2b1: Upper end of lower part 2b 2b2: bottom 2f: thick part 4: Flange part 11: Ironing can 12: Can body 12f: thick part 15: bottom 21: Reducing die 22: Hole 42: (3 steps) Reduced diameter can body 42a: Reduced diameter portion (reduced diameter lower cylindrical portion) 43: Reducing die 52: Rigid punch 56: (1 step) Reduced diameter can body 56a: Reduced diameter portion (reduced diameter lower cylindrical portion) 73: Die 73a: Cavity 101: Deformed seamless can 201: Deformed seamless can 301: Deformed seamless can

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Claims (4)

[Claims] 1. A can body having a cylindrical upper portion and an inverted frustoconical lower portion and having a thick wall at least at or near the boundary between the upper portion and the lower portion. Deformed seamless can, which is characterized by having a section. 2. The deformed seamless can according to claim 1, wherein the lower portion is curved inward. 3. The deformed seamless can according to claim 1, wherein the lower portion is tapered. 4. A metal cup is ironed with a punch having a reduced diameter portion to form an ironing can body having a thick portion corresponding to the reduced diameter portion. The ironing can body is reduced in diameter by a reducing die having a hole having a diameter smaller than the outer diameter, and then the reduced lower portion is expansion-molded into an inverted truncated cone shape, and at least a boundary portion between the upper portion and the lower portion or A method for manufacturing a deformed seamless can, characterized in that a thick portion is provided in the vicinity thereof.