JP2016107341A - Method for manufacturing can - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to prevent an indentation and a pointed part from being left on a can body and impart a beautiful appearance to a can, and to make it possible to improve column strength, even when subjecting a part to be reduced in diameter of the can body to a plurality of times of diameter-reducing processing while reducing the processing diameters of diameter-reducing dies in a stepwise manner.SOLUTION: A method for manufacturing a can includes: a diameter-reducing step of fitting diameter-reducing dies 35 and 36 to the inside and the outside of a can body 11 to subject a part to be reduced in diameter of the can body 11 to a plurality of times of diameter-reducing processing in such a way that a diameter becomes smaller along a can axis O direction from a can bottom toward the side of an opening end part of the can body 11 while reducing the processing diameters of the diameter-reducing dies 35 and 36 in a stepwise manner, thereby forming, in the part to be reduced in diameter, a taper part 21 in which the diameter gradually becomes smaller along the can axis O direction from the can bottom toward the side of the opening end part; and a re-forming step of fitting re-forming dies 55 and 56 to the inside and the outside of the can body 11 to re-form, in the can body 11, the taper part 21, a convex surface part 22 arranged so as to be adjacent to the can bottom side of the taper part 21 and a concave surface part 23 arranged so as to be adjacent to the side of the taper part 21 opposite to the can bottom.SELECTED DRAWING: Figure 10

Description

  The present invention relates to a manufacturing method of a bottomed cylindrical can used for a can body such as a two-piece can or a bottle can filled with a content such as a beverage, and in particular, a can body (wall). In addition, a can suitable for a can body having a constricted portion having a smaller diameter than other portions of the can body, a can body having a neck portion inclined in a wide range in the can axis direction (gradiently inclined), etc. Regarding the method.

As a can body to be filled and sealed with contents such as beverages, a bottomed cylindrical can having a can body (wall) and a can bottom (bottom), and a disc-like shape wound around the open end of the can A two-piece can provided with a can lid is known. The above can is specifically a DI can, and “DI” is an abbreviation for Drawing & Ironing. Also known is a bottle can in which a cap is screwed onto the opening end of the can.
A can used for such a can body is formed into a bottomed cylindrical shape by subjecting a plate of aluminum alloy material to a cupping step (drawing step) and a DI step (drawing and ironing step).

  Patent Document 1 listed below discloses a can body having a constricted portion having a smaller diameter than other portions of the can body. By forming such a constricted portion, the design of the can body can be improved and the ease of holding (grip property) can be improved.

In the case of forming the constricted portion in the can, the following forming process is performed in the constricted portion forming step after the DI step.
That is, as shown in FIG. 11A, with respect to a DI can (can) 10 formed through the DI process, first, a diameter reducing die (punch 35 and die 36) is formed inside and outside the can body 11. ), The diameter of the can body 11 is reduced toward the opening end portion 11a from the can bottom 12 along the can axis O direction. A diameter reduction process is performed (diameter reduction process). Note that the planned diameter reduction is a portion of the can body 11 indicated by reference numeral 18 in FIG.

  Next, as shown in FIG. 11 (b), a diameter-expansion mold (punch 40) is fitted into the inside of the can body 11, and the gap between the opening end portion 11 a of the can body 11 and the planned diameter reduction portion. The diameter-expanding process which becomes a large diameter is given to the diameter-expansion plan part located in (2) along the can-axis O direction from the can bottom 12 toward the opening end part 11a side (diameter expansion process). The diameter expansion planned portion is a can body 11 portion indicated by reference numeral 19 in FIG.

Here, for example, in FIG. 2, when the constricted portion 17 is constricted deeply or constricted in a wide range in the can axis O direction, the diameter-reducing mold 35, A plurality of diameter reduction processes are performed while the process diameter of 36 is gradually reduced (see a plurality of dies 36 shown in FIG. 10). Thereby, the lower part is shape | molded among the constriction parts 17 shown by FIG.
Further, in the diameter expansion step, the diameter expansion scheduled portion 19 is subjected to diameter expansion processing a plurality of times while gradually increasing the processing diameter of the diameter expansion mold 40. As a result, the upper portion of the constricted portion 17 shown in FIG. 2 is formed.

Further, in the necking step that is a step subsequent to the constriction portion forming step (the diameter reducing step and the diameter increasing step), the opening end portion 11a extends from the can bottom 12 to the opening end portion 11a of the can body 11 along the can axis O direction. The neck portion 13 is formed by performing a diameter reduction process that gradually decreases in diameter toward the side.
Specifically, as shown in FIG. 11 (c), a necking die (punch 45 and die 46) is fitted inside and outside of the can body 11, and as shown in FIG. A neck portion 13 having a smaller diameter as it goes upward is formed in the opening end portion 11a of the body 11.

  The opening end portion 11a of the can body 11 before necking is also a diameter reduction planned portion, and when the neck portion 13 is inclined in a wide range (gradually inclined) in the can axis O direction, the opening The end portion 11a is subjected to a plurality of diameter reduction processes while gradually reducing the processing diameters of the necking dies 45 and 46 in the same manner as the diameter reduction process of the constriction part forming process described above.

JP 2003-305523 A

However, the conventional can manufacturing method has the following problems.
That is, in the diameter reduction process or necking process of the constriction part forming process, when the diameter reduction planned part is reduced in stages, the tapered part 21 formed by the diameter reduction process is formed as shown in FIG. Indentation I may occur, or the convex curved surface portion 22 that is disposed adjacent to the can bottom 12 side of the taper portion 21 and protrudes toward the outside of the can body 11 may be buckled and sharpened by a molding load. Here, the term “sharp” means that the vertical cross-sectional shape of the convex curved surface portion 22 has a smaller radius of curvature than the expected radius of curvature (convex R), and is directed to the outside of the can from the surrounding can body 11 portion. It is formed so as to protrude.

  Specifically, when the diameter reduction planned portion of the can body 11 is reduced in diameter, it is easy to form the diameter reduction planned portion along the uneven shape of the die (the inner peripheral tip portion of the die 36). However, in order to suppress the generation of wrinkles, in FIG. 11A, among the inner peripheral front end portion (lower end portion) of the die 36, for example, the mold convex portion 100 is set to a small convex R of about R4 mm to R12 mm. The mold recess 110 is set to a small recess R of about R12 mm.

When such a die 36 is used to reduce the diameter of the can body 11 to be reduced several times while the diameter of the die 36 is reduced stepwise, as shown in FIG. Indentations I and pointed portions S are formed. The pointed portion S is easily formed so as to protrude at a nonuniform height in the circumferential direction of the can body 11.
The indentation I and the pointed portion S are not preferable because they impair the aesthetics of the can body that is the product. Further, the pointed portion S is easily dented or scratched when the can is transported.

  In addition, in the longitudinal sectional view of the can 10 shown in FIG. 10, an inclination angle θ (tapered portion 21 and can axis O formed between the can body 11 and the tapered portion 21 with a reduced diameter of the can body 11 and the can axis O. In the case where the acute angle between the acute angle and the obtuse angle formed between them is set to be smaller than 20 °, for example, the tapered portion 21 is in a so-called “standing” state, and the can 10 While it becomes easy to ensure the column strength (strength against the load in the direction of the can axis O), the indentation I is more likely to occur. This is because it is difficult to secure a contact area between the mold convex portion 100 of the die 36 and the tapered portion 21 formed on the can body 11.

  The present invention has been made in view of such circumstances, and the diameter reduction portion of the can body is subjected to diameter reduction processing a plurality of times while gradually reducing the diameter of the diameter reduction mold. In addition, there is provided a method for manufacturing a can that can prevent an impression or a pointed portion from being left on the can body, impart a beautiful appearance to the can, and increase the column strength. The purpose is that.

In order to solve such problems and achieve the above object, the present invention proposes the following means.
That is, the present invention is a method of manufacturing a bottomed cylindrical can having a can body and a can bottom, wherein a diameter reducing mold is fitted inside and outside the can body, and the diameter of the can body is reduced. A plurality of diameter-reducing processes, which are reduced in diameter toward the opening end side of the can body from the can bottom along the can axis direction, while reducing the diameter of the reduced-diameter mold in stages. The diameter reduction step of forming a taper portion that gradually decreases in diameter toward the opening end side from the bottom of the can along the axial direction of the can, A remodeling mold is fitted to the outside, and among the can body, the tapered portion, a convex curved surface portion that is arranged adjacent to the can bottom side of the tapered portion and is convex toward the outside of the can body, and A concave curved surface portion that is disposed adjacent to the opposite side of the can bottom of the tapered portion and is concave toward the inside of the can body. Characterized in that it comprises a remodeling process of the.

  According to the method for manufacturing a can according to the present invention, in the diameter reduction process, the diameter reduction processing is performed a plurality of times while the diameter of the diameter reduction mold is gradually reduced with respect to the planned diameter reduction portion of the can body. Even if an indentation is formed in the taper portion or a pointed portion is formed on the convex curved surface portion adjacent to the can bottom side of the taper portion, the taper portion is formed in the subsequent reforming process. In order to re-form the convex curved surface portion disposed adjacent to the can bottom side of the tapered portion and the concave curved surface portion disposed adjacent to the side opposite to the can bottom of the tapered portion with a remodeling mold. The following remarkable effects can be obtained.

That is, by re-forming the can body in the reforming step, the surface of the taper portion can be flattened and the indentation can be eliminated. Moreover, about a convex curve part, a sharp part can be rounded and the shape (convex R shape) can be prepared so that it may become the expected curvature radius.
In addition, the remodeling process involves not only the tapered part and the convex curved part, but also the concave curved part adjacent to the side opposite to the can bottom of the tapered part, so that the convex curved part is changed to the concave curved part. The meat of the can body becomes easier to flow toward, and the shape (concave R shape) of this concave curved surface part can be adjusted to have the desired radius of curvature, and the thickness is secured and the strength is stable. Can be made.

In addition, in a vertical cross-sectional view of the can, an inclination angle formed between the tapered portion of the can body that has been reduced in diameter and the can shaft (out of an acute angle and an obtuse angle formed between the tapered portion and the can shaft) In the case where the acute angle is set to a small value of 20 ° or less, for example, the tapered portion is in a so-called “standing” state, and the column strength of the can (strength against the load in the can axis direction) is ensured. While becoming easier, indentations are more likely to occur.
Even if the taper portion is in a standing state, the indentation of the taper portion can be easily and surely eliminated according to the present invention. It is possible to maintain it well.
In the present invention, the inclination angle is preferably 8 to 20 °, and desirably 8 to 10 °.

Further, in the reforming process, the roundness (cylindricity) of the can body is improved by remolding the tapered portion, the convex curved surface portion, and the concave curved surface portion by the remodeling mold.
That is, in general, the diameter of the can body varies in the circumferential direction around the can axis even at the same position along the can axis direction (the difference in diameter occurs due to material anisotropy) The above-described variation in the diameter of the can body can be reduced by simultaneously pressing the can body in the entire circumferential direction by the remodeling mold. Thereby, the column strength of the can body can be stably improved.
In addition, since the shape can be adjusted so that the roundness (cylindricity) and the diameter of the can body become the expected values by the remodeling process, for example, a diameter expansion process or flanging performed as a subsequent process of the remodeling process. In the process and the like, the guide diameter portion (particularly the concave curved surface portion) of the can body that becomes a reference at the time of processing can be accurately formed. This improves the accuracy of processing the can body that is performed in a later process than the reforming process, so that the quality of the shape of the manufactured can can be stably improved, and the can can be formed with a beautiful appearance. it can.

Further, for example, in the case where a constricted portion having a smaller diameter than other portions of the can body is formed on the can body, a diameter expanding step is performed after the above-described diameter reducing step and reforming step. In the diameter expansion process, a mold for expanding the diameter is fitted into the inside of the can body, and along the can axis direction, on the diameter expansion planned portion located between the opening end of the can body and the diameter reduction planned portion. A diameter expansion process is performed so that the diameter increases from the bottom of the can toward the opening end.
Even in the case of performing such a diameter expanding process, according to the present invention, the column strength of the can body is increased as described above, so that the can body is prevented from buckling during processing. , Manufacturing is stable.

  As described above, according to the present invention, an indentation or a sharp point is applied to the can body while the diameter reduction portion of the can body is subjected to a plurality of diameter reduction processes while gradually reducing the working diameter of the diameter reducing mold. It is possible to prevent the remaining portion from being left, to give the can a beautiful appearance, and to increase the column strength.

  Further, in the can manufacturing method of the present invention, the reforming step includes a first reforming step of reforming the convex curved surface portion and a second reforming step of reforming the concave curved surface portion, In at least one of the first reforming process and the second reforming process, the tapered portion may be reshaped.

  In this case, since the reforming step includes the first reforming step and the second reforming step, the convex curved surface portion, the taper portion, and the concave curved surface portion can be remolded step by step. Specifically, first, in the first reforming step, at least the convex curved surface portion of the convex curved surface portion and the tapered portion is reshaped. Then, in the next second reforming step, at least the concave curved surface portion of the tapered portion and the concave curved surface portion is reshaped. In addition, about a taper part, you may reshape only in any one process among a 1st reforming process and a 2nd reforming process, and in both processes, for example, a process part is divided and reshaped. You may shape | mold.

In this way, the processing accuracy of the convex curved surface portion and the concave curved surface portion can be improved by reforming the convex curved surface portion and the concave curved surface portion of the can body in separate steps. Specifically, with respect to the convex curved surface portion, the sharp portion can be stably rounded, and the shape can be accurately adjusted so that the desired curvature radius is obtained. In addition, the shape of the concave curved surface portion can be accurately adjusted so that the desired radius of curvature can be obtained and the roundness (cylindricity) and diameter of the can body can be expected values. . Further, the taper portion also has an effect that the indentation can be stably eliminated.
In particular, since the roundness and diameter of the concave curved surface can be reshaped with high accuracy by the second remodeling process, the processing accuracy in the diameter expansion process and flanging process in the subsequent process of the remodeling process is remarkably increased. Will be.

  In the can manufacturing method of the present invention, in the reforming step, the tapered portion, the convex curved surface portion, and the concave curved surface portion may be simultaneously remolded.

  In this case, since the reforming process can be completed by a single process, the ease of manufacturing is improved.

  Further, in the can manufacturing method of the present invention, in the diameter reducing step, a convex curved surface portion that is formed so as to protrude toward the outside of the can body by forming a portion of the tapered portion that is disposed adjacent to the can bottom side. In the reforming step, the convex curved surface portion may be reshaped so that the curvature radius is larger than the curvature radius of the convex curved surface portion formed in the diameter reducing step in the longitudinal sectional view of the can. Good.

In this case, since the radius of curvature of the convex curved surface portion can be increased step by step for each process, first, in the diameter reducing step, the radius of curvature of the convex curved surface portion to be formed is set small so that the convex curved surface portion is formed. It is possible to reliably prevent the occurrence of wrinkles. Further, in the subsequent reforming step, the convex curved surface portion can be accurately reshaped into a large convex R shape so that the convex curved surface portion has a desired radius of curvature as a product.
In the remodeling process, by setting the radius of curvature of the convex curved surface portion to be large, the meat of the can body easily flows from the convex curved surface portion to the concave curved surface portion at the time of the re-forming, and the above-described operational effects are further remarkable. It will be a thing.

  Further, in the method for manufacturing a can according to the present invention, the diameter-reduced portion is disposed on the can bottom side with respect to the opening end portion of the can body, and the can can be used as a subsequent step of the reforming step. A diameter-expansion mold is fitted inside the barrel, and the diameter-expanded portion located between the opening end portion and the diameter-reduced portion of the can barrel is extended from the bottom of the can along the can axis direction. It is good also as providing the diameter expansion process which performs the diameter expansion process which becomes a large diameter as it goes to the said opening edge part side.

In this case, after the diameter reduction processing is performed on the diameter reduction planned portion of the can body, the diameter expansion processing is performed on the diameter expansion scheduled portion so that the diameter of the can body is smaller than other portions. Part is formed. By forming such a constricted portion, it is possible to improve the design of the can body, improve the ease of holding (grip property), and increase the product value.
According to the present invention, since the column strength of the can body is increased as described above, it is possible to prevent the can body from buckling during diameter expansion processing.

  Further, in the method for manufacturing a can according to the present invention, the planned diameter reduction portion is disposed at the opening end portion of the can body, and a neck is formed at the opening end portion by the diameter reducing step and the reforming step. A part may be formed.

  In this case, the neck portion can be inclined in a wide range (gradually inclined) in the can axis direction without leaving an indentation or a pointed portion on the neck portion. Thereby, the design property of a can can be improved and product value can be improved.

  According to the method for manufacturing a can according to the present invention, the can body is subjected to a plurality of times of diameter reduction while gradually reducing the diameter of the diameter reduction mold to the diameter reduction planned portion of the can body. It is possible to prevent the impressions and sharp parts from being left behind, to give the can a beautiful appearance, and to increase the column strength.

It is a perspective view which shows the can which concerns on one Embodiment of this invention. It is a longitudinal section showing a can concerning one embodiment of the present invention. It is a flowchart explaining the manufacturing method of the can which concerns on one Embodiment of this invention. It is a figure explaining the manufacturing method (a cupping process, DI process, and trimming process) of the can which concerns on one Embodiment of this invention. In the manufacturing method of the can which concerns on one Embodiment of this invention, it is a figure explaining the diameter reduction process of a constriction part formation process. In the manufacturing method of the can which concerns on one Embodiment of this invention, it is a figure explaining the reform process of a constriction part formation process. In the manufacturing method of the can which concerns on one Embodiment of this invention, it is a figure explaining the diameter expansion process of a constriction part shaping | molding process. It is a figure explaining a necking process in the manufacturing method of the can concerning one embodiment of the present invention. It is a figure explaining a flanging process in the manufacturing method of the can concerning one embodiment of the present invention. It is a fragmentary longitudinal cross-sectional view explaining the diameter reduction process and the remodeling process in the manufacturing method of a can. It is a fragmentary longitudinal cross-section explaining (a) diameter reduction process, (b) diameter expansion process, and (c) necking process in the manufacturing method of a can. It is a flowchart explaining the modification of the manufacturing method of the can which concerns on one Embodiment of this invention. In the modification of the manufacturing method of the can which concerns on one Embodiment of this invention, it is a figure explaining the reform process (1st reform process) of a constriction part formation process. In the modification of the manufacturing method of the can which concerns on one Embodiment of this invention, it is a figure explaining the reform process (2nd reform process) of a constriction part formation process.

Hereinafter, a can 10 and a manufacturing method thereof according to an embodiment of the present invention will be described with reference to the drawings.
As FIG. 1 shows, the can 10 of this embodiment is used for the can (2 piece can) by which the contents, such as a drink, are filled and sealed. The can body includes a bottomed cylindrical can 10 and a disk-like can lid (not shown) wound around the open end portion 11a of the can 10. The can 10 is specifically a DI can, and “DI” is an abbreviation for Drawing & Ironing. In addition, although the can 10 of this embodiment is used for a 211/204 diameter can, it is not limited to this, For example, it may be used for a 211/206 diameter can. Further, the present invention may be applied to a 204/200 diameter can or a 204/202 diameter can whose outer diameter is thinner than that.

  As shown in FIGS. 1 and 2, the can 10 includes a cylindrical can body (wall) 11 and a generally disc-shaped can bottom (bottom) 12. In addition, while the can 10 shown by FIG.1 and FIG.2 passed through the necking process mentioned later, the state before the flanging process is represented.

In FIG. 2, the can body 11 and the can bottom 12 are arranged coaxially with each other. In this specification, the common shaft is referred to as a can shaft O.
Of the directions along the can axis O (the direction of the can axis O), the direction from the open end 11a of the can body 11 toward the can bottom 12 is downward, and the direction from the can bottom 12 toward the open end 11a is upward. That's it.
A direction orthogonal to the can axis O is referred to as a radial direction, and a direction approaching the can axis O in the radial direction is referred to as an inner side in the radial direction, and a direction away from the can axis O is referred to as an outer side in the radial direction.
Further, a direction around the can axis O is referred to as a circumferential direction.

  An upper end portion of the can body 11 is an open end portion 11 a that opens to the outside of the can 10. The contents are filled into the can 10 through the open end 11a. The lower end of the can body 11 is closed by the can bottom 12. The outer diameter of the can body 11 is, for example, 65 to 67 mm.

  The can body 11 is formed with a constricted portion 17 having a smaller diameter than other portions of the can body 11. The constricted portion 17 is disposed at a portion of the can body 11 other than the open end portion 11a. Specifically, in the present embodiment, the constricted portion 17 is formed at an intermediate portion between the upper end portion (open end portion 11a) and the lower end portion of the can body 11.

In the external view of the can 10 shown in FIG. 1, the constricted portion 17 is formed on the can body 11 in a concave curved surface shape. Specifically, in this external view, the constricted portion 17 is recessed toward the inner side in the radial direction with respect to the other portion of the intermediate portion of the can body 11 and is disposed on the entire circumference of the can body 11 along the circumferential direction. It has an extending ring shape.
The depth at which the constricted portion 17 is retracted (recessed) inward in the radial direction with respect to the portion other than the constricted portion 17 in the intermediate portion is, for example, 4 to 15 mm, and is about 8 mm in the present embodiment. .

In the longitudinal sectional view of the can 10 shown in FIG. 2, the constricted portion 17 has a concave curve shape that is recessed toward the inside (inside in the radial direction) of the can body 11.
The constricted portion 17 is formed by reducing the diameter reduction planned portion 18 of the can body 11 and performing a diameter reduction process and a reforming process (reforming process). The diameter-expanded portion 19 of the can body 11 is formed by diameter-expansion processing, and the diameter-expanded portion expands toward the upper side (becomes a larger diameter). .
The planned diameter reduction part 18 and the planned diameter expansion part 19 of the can body 11 will be described separately in the description of the method for manufacturing the can 10 described later.

Of the constricted portion 17, the reduced diameter portion disposed in the lower portion is disposed adjacent to the tapered portion 21, which gradually decreases in diameter toward the upper side, and below the tapered portion 21 (on the can bottom 12 side). A convex curved surface portion 22 that is convex outward, and a concave curved surface portion 23 that is disposed adjacently above the taper portion 21 (on the side opposite to the can bottom 12) and that is concave toward the inside of the can body 11. Have. The tapered portion 21, the convex curved surface portion 22, and the concave curved surface portion 23 each have an annular shape that extends over the entire circumference of the can body 11.
The convex curved surface part 22, the taper part 21, and the concave curved surface part 23 are smoothly connected to each other (that is, smoothly connected without forming a step between them. The same applies hereinafter). Specifically, in the longitudinal sectional view of the can 10 shown in FIG. 2, the tapered portion 21 is a tangent line that contacts and connects the convex curved surface portion 22 and the concave curved surface portion 23.

Of the constricted portion 17, the enlarged-diameter portion disposed in the upper portion is a tapered portion 31 that gradually increases in diameter as it goes upward, and is disposed adjacent to the upper portion of the tapered portion 31 and protrudes toward the outside of the can body 11. A convex curved surface portion 32, and a concave curved surface portion 33 that is disposed adjacently below the tapered portion 31 and is concave toward the inside of the can body 11. Further, the tapered portion 31, the convex curved surface portion 32 and the concave curved surface portion 33 each have an annular shape extending over the entire circumference of the can body 11.
The convex curved surface portion 32, the tapered portion 31 and the concave curved surface portion 33 are smoothly connected to each other. Specifically, in the longitudinal sectional view of the can 10 shown in FIG. 2, the tapered portion 31 is a tangent line that contacts and connects the convex curved surface portion 32 and the concave curved surface portion 33.

The convex curved surface portion 22 of the reduced diameter portion and the portion of the can body 11 (the portion of the can body 11 having the largest diameter) arranged adjacently below the convex curved surface portion 22 are smoothly connected.
The convex curved surface portion 32 of the enlarged diameter portion and the portion of the can body 11 (the portion of the can body 11 having the largest diameter) arranged adjacently above the convex curved surface portion 32 are connected smoothly.
Further, the concave curved surface portion 23 of the reduced diameter portion and the concave curved surface portion 33 of the enlarged diameter portion are smoothly connected.

  In the longitudinal sectional view of the can 10 shown in FIG. 2, the respective curvature radii (the curvature radii on the outer peripheral surface of the can body 11) of the convex curved surface portions 22 and 32 and the concave curved surface portions 23 and 33 of the can body 11 as a product are, for example, , R60 mm to R80 mm. However, the radius of curvature is not limited to the above numerical range.

The opening end 11 a of the can body 11 is formed with a neck portion 13 that decreases in diameter as it goes upward, and a cylindrical flange planned portion 14 that is disposed above the neck portion 13.
The neck portion 13 has a taper portion 51 that gradually becomes smaller in diameter toward the upper side, a convex curved surface portion 52 that is disposed adjacent to the lower portion of the taper portion 51 and protrudes toward the outside of the can body 11, and an upper portion of the taper portion 51. And a concave curved surface portion 53 that is disposed adjacent to the inner surface of the can body 11 and is concave toward the inside. The tapered portion 51, the convex curved surface portion 52, and the concave curved surface portion 53 each have an annular shape that extends over the entire circumference of the can body 11.
The convex curved surface portion 52, the tapered portion 51, and the concave curved surface portion 53 are smoothly connected to each other. Specifically, in the longitudinal sectional view of the can 10 shown in FIG. 2, the tapered portion 51 is a tangent line that contacts and connects the convex curved surface portion 52 and the concave curved surface portion 53.

The convex curved surface portion 52 of the neck portion 13 and the can body 11 portion (the portion of the can body 11 having the largest diameter) arranged adjacent to the lower side of the convex curved surface portion 52 are smoothly connected. The concave curved surface portion 53 of the neck portion 13 and the planned flange portion 14 disposed adjacently above the concave curved surface portion 53 are smoothly connected.
Further, the lower end portion of the can body 11 is smoothly connected to the upper end portion of a heel portion 12c described later of the can bottom 12.

  The can bottom 12 is located on the can axis O and is formed so as to bulge upward (inside the can body 11), the outer peripheral edge of the dome portion 12a, and the can body 11 A heel portion 12c connecting the lower end of the heel portion 12c.

  In the longitudinal sectional view shown in FIG. 2, the heel portion 12 c is gradually inclined inward in the radial direction from the lower end portion of the can body 11 toward the lower side. Further, in this longitudinal cross-sectional view, the connection portion of the heel portion 12 c with the lower end portion of the can body 11 (that is, the upper end portion of the heel portion 12 c) has a convex curve shape protruding toward the outside of the can body 11.

  Further, the connecting portion between the dome portion 12a and the heel portion 12c in the can bottom 12 is such that the can 10 is in an upright posture (the posture in which the open end portion 11a of the can body 11 faces upward as shown in FIG. 2). When this is placed on the grounding surface (mounting surface), the grounding portion 12b is in contact with the grounding surface. The ground contact portion 12b protrudes downward most in the can bottom 12 and has an annular shape extending along the circumferential direction.

2 represents a virtual horizontal plane that passes through the center of the radius of curvature of the convex curve formed by the upper end of the heel portion 12c and is perpendicular to the can axis O.
In the present specification, of the peripheral wall (outer peripheral wall) of the can 10, a portion located above the virtual horizontal plane H is the can body 11, and a portion located below the virtual horizontal plane H is the can bottom 12. Yes. Specifically, on the peripheral wall of the can 10, a portion of the can bottom 12 located below the virtual horizontal plane H is a heel portion 12 c.

Next, an example of a method of manufacturing the bottomed cylindrical can 10 from a plate material (blank) W made of an aluminum alloy material will be described with reference to FIGS.
As shown in FIG. 3, the can 10 includes a plate blanking process, a cupping process (drawing process), a DI process (drawing and ironing process), a trimming process, a printing process, a painting process, and a constricted part forming process (reducing diameter process, reforming). Can be made through a necking process and a flanging process in this order.

[Sheet punching process]
An ingot made of an Al alloy material is subjected to hot rolling, cold rolling and annealing to form an intermediate plate having a predetermined thickness, and then the intermediate plate is subjected to cold finish rolling to obtain a final thickness. A material is prepared, the rolled material is punched, and a disk-shaped plate material (blank) W is formed (punched) as shown in FIG.

[Cupping process (drawing process)]
Next, as shown in FIG. 4B, the plate material W is drawn (cupped) by a cupping press to form a cup-shaped body W1. The cup-shaped body W1 is a forming intermediate body that shifts from the plate material W to a can W2 (can 10 before trimming) described later.

[DI process (drawing and ironing process)]
Next, as shown in FIG. 4 (c), the cup-shaped body W <b> 1 is subjected to DI processing (re-drawing and ironing processing) by a DI processing apparatus to form a bottomed cylindrical shape including a can body 11 and a can bottom 12. Molded into can W2.

  The DI processing apparatus includes a single redrawing die having a circular through hole for redrawing, and a plurality of (for example, three) pieces having a circular through hole arranged coaxially with the redrawing die. A cylindrical or circular shape that is coaxial with the ironing die and ironing die, can be fitted into each of the through holes of the ironing die, and can move in the axial direction of the die. A columnar punch sleeve and a cylindrical cup holder sleeve fitted to the outside of the punch sleeve are provided.

In the redrawing process by the DI processing apparatus, the cup-shaped body W1 is arranged between the punch sleeve and the redrawing die, the cup holder sleeve and the punch sleeve are advanced, and the cup holder sleeve is cupped on the end face of the redrawing die. The punch sleeve pushes the cup-shaped body W1 into the through-hole of the redraw die while pressing the bottom surface of the shaped body W1 to perform the cup pressing operation.
As a result, a redrawn cup-like body (not shown) having a predetermined inner diameter is formed. Subsequently, the redrawn cup-shaped body is passed through a plurality of ironing dies one after another and gradually squeezed to squeeze the peripheral wall of the cup-shaped body and extend the peripheral wall to increase the peripheral wall height. At the same time, the wall thickness is reduced to form a bottomed cylindrical can W2.

After the ironing process has been completed, the bottom of the can W2 is formed in the above-described dome shape by pressing the bottom portion (the portion that becomes the can bottom 12) against the bottom molding die.
The can W2 is cold-worked and hardened by squeezing the peripheral wall as described above, and the strength is increased.

As shown in FIG. 4C, the opening end 11a of the can W2 that has undergone the cupping process and the DI process is formed in an uneven shape (uneven wave shape) that waves up and down as it goes in the circumferential direction. In addition, this uneven | corrugated wave shape is provided from the time of shape | molding the board | plate material W in the cup-shaped body W1.
A portion (convex portion) that is a peak projecting upward in the upper end edge of the concavo-convex wave shape of the opening end portion 11 a is called an ear 20. A plurality of ears 20 are formed along the circumferential direction at the open end 11a. These ears 20 are caused by, for example, the crystallographic anisotropy of an aluminum alloy.

[Trimming process]
Next, the opening end 11a of the can W2 is trimmed.
That is, the opening end 11a of the can W2 formed by the DI processing apparatus has the ear 20 formed and the height thereof is non-uniform, so that the opening end 11a of the can W2 is cut and trimmed. As shown in FIG. 4D, the height of the peripheral wall along the can axis O direction at the opening end portion 11a of the can body 11 is made uniform over the entire circumference.
Thereby, the can 10 after the trimming process which does not have the ear | edge 20 in the opening edge part 11a of the can body 11 (the ear | edge 20 was cut off) is obtained. The height of the can 10 in the direction of the can axis O (the height from the lower end of the can bottom 12 (grounding portion 12b) to the upper end of the opening end portion 11a) is, for example, about 124 mm in the case of a 350 ml can. In the case of a 500 ml can, it is about 168 mm.

[Printing process, painting process]
After cleaning the can 10 and removing the lubricating oil, etc., it is subjected to a surface treatment and dried, followed by outer surface printing and outer surface coating, and then inner surface coating.
Specifically, in the printing process, printing on the outer surface of the can body 11 of the can 10 is performed using printing ink.
Next, in the painting process, after applying the outer surface coating, the inner surface coating is performed. Specifically, for example, the outer surface of the can body 11 of the can 10 is coated using a polyester-based paint, and the can 10 coated with the outer surface is dried by heating in an oven. When drying by heating in an oven, a transfer pin extending in a substantially horizontal direction is inserted from the open end 11a of the can body 11 into the inside, and the transfer pin supports the can 10, It is moved by a drive mechanism including a chain, a motor, and the like. Next, the inner surface of the can body 11 and the can bottom 12 of the can 10 is coated using, for example, an epoxy paint, and the can 10 coated with the inner surface is dried by heating in an oven.

[Reducing diameter process (constriction part forming process)]
Next, as shown in FIGS. 5A and 5B and FIG. 11A, the diameter-reducing molds 35 and 36 are fitted inside and outside the can body 11 of the can 10, and FIG. As shown, the diameter of the can body 11 that is closer to the bottom of the can 12 than the open end 11a of the can 11 is reduced from the bottom 12 to the open end 11a along the can axis O direction. Reduce the diameter to a small diameter.

The planned diameter reduction portion 18 is located in a portion other than the opening end portion 11a in the can body 11, and specifically, is arranged to be spaced downward from the opening end portion 11a.
In the example of this embodiment, in FIG. 2, the planned diameter reduction portion 18 is disposed between the upper end portion (opening end portion 11 a) and the lower end portion of the can body 11.

  Specifically, in FIGS. 5A, 5 </ b> B, and 11 </ b> A, the punch 35 that fits inside the can body 11 and the outside of the can body 11 are fitted as a diameter reducing mold. A die 36 is used. The central axes of the diameter-reducing molds 35 and 36 are arranged coaxially with the can axis O. Then, between these punches 35 and the die 36, the entire region from the opening end portion 11a of the can body 11 to the diameter reduction planned portion 18 is reduced.

  That is, in the diameter reducing step, the diameter reducing molds 35 and 36 are arranged apart from the upper portion of the can 10, and the diameter reducing molds 35 and 36 and the can 10 are moved in the direction of the can axis O. The can body 11 of the can 10 is entered from the opening end portion 11a between the punch 35 and the die 36 of the diameter-reducing mold while moving relatively close to each other, and from the opening end portion 11a of the can body 11 The entire region up to the planned diameter reduction portion 18 is reduced.

Specifically, a portion of the outer peripheral surface of the punch 35 corresponding to a region from the opening end portion 11a of the can body 11 along the can axis O direction (the central axis direction of the punch 35) to the planned diameter reduction portion 18 is constant. The outer diameter is formed.
Further, of the inner peripheral surface of the die 36, a portion adjacent to the upper diameter-reducing portion 18 from the opening end portion 11 a of the can body 11 along the can axis O direction (the central axis direction of the die 36). The site | part corresponding to the area | region to 19) is formed in the fixed internal diameter.

Further, in FIG. 11A, a die that gradually decreases in diameter toward the upper end (inner peripheral front end) corresponding to the diameter reduction planned portion 18 of the can body 11 among the inner peripheral surface of the die 36. A taper part, an annular mold convex part 100 that is arranged adjacent to the upper part of the mold taper part and projects radially inward and downward, and extends over the entire circumference in the circumferential direction, and adjacent to the lower part of the mold taper part An annular mold recess 110 is formed that is disposed and is recessed radially outward and upward, and extending over the entire circumference in the circumferential direction.
Specifically, the mold convex portion 100 is formed in a convex curved surface shape, and the mold concave portion 110 is formed in a concave curved surface shape. For example, the mold convex portion 100 is set to a small convex R of about R4 mm to R12 mm, and the mold concave portion 110 is set to a small concave R of about R12 mm.

5 (a) and 5 (b), during the diameter reduction processing, first, the punch 35 of the diameter reduction dies 35 and 36 moves toward the can 10 in the direction of the can axis O while moving toward the can axis O. 11, and then the die 36 is fitted to the outside of the can body 11 while moving (advancing) in the direction of the can axis O with respect to the can 10, so that the open end 11 a of the can body 11 is fitted. To the diameter reduction planned portion 18 is subjected to diameter reduction processing.
Further, after the diameter reduction processing, the die 36 of the diameter reduction dies 35 and 36 is first separated from the outside of the can body 11 while being moved away (retracted) in the direction of the can axis O with respect to the can 10. The punch 35 is moved away from the inside of the can body 11 while moving away (retracted) in the direction of the can axis O with respect to the can 10, and the diameter reducing dies 35 and 36 are moved to their original positions (processing preparation position, standby). Return to position.

  The timing at which the punch 35 and the die 36 are fitted to the can body 11 of the can 10 is not limited to that described in the present embodiment. For example, the punch 35 and the die 36 are attached to the can 10. At the same time, it may be moved closer or / and separated.

  Then, by subjecting the diameter reduction planned portion 18 to diameter reduction processing a plurality of times while gradually reducing the processing diameter of the diameter reduction molds 35 and 36, a concave curve shape is obtained in a longitudinal sectional view shown in FIG. Of the constricted portion 17, the reduced diameter portion (the convex curved surface portion 22, the tapered portion 21 and the concave curved surface portion 23) located at the lower portion is formed. Note that, in the plurality of diameter reduction processes, the same diameter reduction process as described above is performed on the entire region from the opening end portion 11 a of the can body 11 to the diameter reduction scheduled portion 18.

  As described above, by performing the diameter reduction processing a plurality of times, the diameter-reduced portion can be greatly inclined or inclined in a wide range without damaging the can body 11, and the constricted portion 17 is constricted into various shapes. It becomes possible to make it.

Specifically, in the diameter reduction process, at least the tapered portion 21 is formed in the diameter reduction scheduled portion 18. In the present embodiment, as shown in FIG. 10, in the diameter reduction process, while forming the taper portion 21, a portion adjacent to the lower portion of the taper portion 21 is formed and protrudes toward the outside of the can body 11. A convex curved surface portion 22 is formed, and a portion adjacent to the upper portion of the tapered portion 21 is formed to form a concave curved surface portion 23 that is concave toward the inside of the can body 11.
However, the convex curved surface part 22 formed in the diameter reducing step has a curvature radius in the longitudinal sectional view of the can 10 smaller than an expected curvature radius given to the convex curved surface part 22 of the can 10 to be a product. It is molded into a small R of about R10mm.

  That is, the shape corresponding to the die taper portion is transferred as the taper portion 21 to the planned diameter reduction portion 18 at the inner peripheral tip portions of the plurality of dies 36. In addition, the shape corresponding to the mold concave portion 110 is transferred to the planned diameter reduction portion 18 as the convex curved surface portion 22 at the inner peripheral tip portions of the plurality of dies 36. Further, among the plurality of dies 36, the shape corresponding to the mold convex portion 100 is transferred to the planned diameter reduction portion 18 as the concave curved surface portion 23 at the inner peripheral tip portion of the die 36 used for the final diameter reduction processing. The

  In the diameter reduction process, instead of forming the convex curved surface portion 22 and the concave curved surface portion 23 as described above, for example, angular convex portions and concave portions may be formed in the can body 11. Even in the case where such convex portions and concave portions are formed, in this embodiment, the convex curved surface portion 22 and the concave curved surface of the final shape (the shape to be given to the product) are obtained by re-forming in a reforming process described later. Part 23 can be used.

[Reform process (constriction part forming process)]
Next, as shown in FIGS. 6A and 6B and FIG. 10, remodeling molds 55 and 56 are fitted inside and outside the can body 11 of the can 10, and the taper of the can body 11 is tapered. The part 21, the convex curved surface part 22, and the concave curved surface part 23 are reshaped. In the example of this embodiment, the taper part 21, the convex curved surface part 22, and the concave curved surface part 23 are simultaneously remolded in the reforming step.

  Specifically, a punch 55 that fits inside the can body 11 and a die 56 that fits outside the can body 11 are used as remodeling molds. The central axes of the reforming molds 55 and 56 are arranged coaxially with the can axis O. Then, between the punch 55 and the die 56, at least the tapered portion 21, the convex curved surface portion 22, and the concave curved surface portion 23 of the can body 11 are remolded at a time and reformed. At the time of this reforming process, for example, the entire region from the open end 11a of the can body 11 to the concave curved surface part 23 may be reduced in diameter.

  In the reforming process, the reforming molds 55 and 56 and the can 10 are relatively moved closer to each other in the direction of the can axis O from the state where the reforming molds 55 and 56 are separated from each other above the can 10. The can body 11 of the can 10 is made to enter from the opening end portion 11a between the punch 55 and the die 56 of the reforming mold.

Specifically, the portion of the outer peripheral surface of the punch 55 that corresponds to the region from the open end portion 11a of the can body 11 along the can axis O direction (the central axis direction of the punch 55) to the convex curved surface portion 22 is constant outside. It is formed in the diameter.
Further, a portion of the inner peripheral surface of the die 56 adjacent to the upper portion of the concave curved surface portion 23 from the opening end portion 11a of the can body 11 along the direction of the can axis O (the direction of the central axis of the die 56) (the planned diameter expansion portion 19). The part corresponding to the region up to) is formed with a constant inner diameter.

Further, in FIG. 10, of the inner peripheral surface of the die 56, the tip portion (inner peripheral tip portion) corresponding to the reduced diameter portion (taper portion 21, convex curved surface portion 22 and concave curved surface portion 23) of the can body 11 is A mold taper portion 57 that gradually decreases in diameter toward the upper side, and an annular mold protrusion that is disposed adjacent to the upper side of the mold taper portion 57 and protrudes radially inward and downward and extends over the entire circumference in the circumferential direction. A portion 58 and an annular mold recess 59 that is disposed adjacent to the lower side of the mold taper portion 57 and is recessed radially outward and upward and extending over the entire circumference in the circumferential direction are formed.
Specifically, the mold convex portion 58 is formed in a convex curved surface shape, and the mold concave portion 59 is formed in a concave curved surface shape. For example, the mold convex portion 58 is set to a large convex R of about R60 mm, and the mold concave portion 59 is set to a large concave R of about R80 mm.

6 (a) and 6 (b), during the remodeling process, first, the punch 55 of the remodeling molds 55 and 56 moves toward (forwards) the can 10 in the direction of the can axis O while moving inside the can body 11. Next, the die 56 is fitted to the outside of the can body 11 while moving (advancing) in the direction of the can axis O with respect to the can 10, and is reshaped to a reduced diameter portion of the can body 11. Processing (reform processing) is performed.
In addition, after the remodeling process, the die 56 of the remodeling molds 55 and 56 is first separated from the outside of the can body 11 while being moved away (retracted) from the can 10 in the direction of the can axis O, and then punched. 55 is moved away from (retracted from) the can 10 in the direction of the can axis O and is removed from the inside of the can body 11, so that the remodeling molds 55 and 56 return to their original positions (processing preparation position, standby position). Return.

  The timing at which the punch 55 and the die 56 are fitted into the can body 11 of the can 10 is not limited to that described in the present embodiment. For example, the punch 55 and the die 56 are attached to the can 10. At the same time, it may be moved closer or / and separated.

  Specifically, in this reforming step, the convex curved surface is set so that the curvature radius R1 is larger than the curvature radius of the convex curved surface portion 22 formed in the above-mentioned diameter reducing step in the longitudinal sectional view of the can 10 shown in FIG. The part 22 is reshaped. In the present embodiment, the radius of curvature R1 is set to R80 mm, for example. In addition, the concave curved surface portion 23 is reshaped so that the radius of curvature R2 is larger than the radius of curvature of the concave curved surface portion 23 formed in the above-described diameter reducing step. In the present embodiment, the radius of curvature R2 is set to R60 mm, for example. Further, the taper portion 21 is re-molded so that the surface of the taper portion 21 formed in the above-described diameter reducing step is flattened.

That is, the shape corresponding to the die taper portion 57 is transferred to the taper portion 21 of the can body 11 at the inner peripheral tip portion of the die 56. In addition, the shape corresponding to the mold concave portion 59 is transferred to the convex curved surface portion 22 of the can body 11 at the inner peripheral tip portion of the die 56. In addition, the shape corresponding to the mold convex portion 58 is transferred to the concave curved surface portion 23 of the can body 11 at the inner peripheral tip portion of the die 56.
In the remodeling process, a springback phenomenon may occur after the remodeling process, and an R shape slightly smaller than the curvature radii R1 and R2 that are expected for the convex curved surface portion 22 and the concave curved surface portion 23 may be imparted.

[Diameter expansion process (constriction part forming process)]
Next, as shown in FIGS. 7 (a), 7 (b) and 11 (b), a diameter expanding die 40 is fitted into the inside of the can body 11 of the can 10, and as shown in FIG. In the can body 11, the diameter-expanding portion 19 located between the opening end portion 11 a and the diameter-decreasing portion 18 increases in the direction from the can bottom 12 toward the opening end portion 11 a along the can axis O direction. A diameter expansion process is performed.

The diameter-expanded portion 19 is located in a portion of the can body 11 other than the opening end portion 11a and the diameter-reduced portion 18 and, specifically, is spaced apart from the opening end portion 11a. Further, it is arranged adjacent to the upper portion of the diameter reduction scheduled portion 18.
In addition, the diameter expansion plan part 19 may be spaced apart above the diameter reduction plan part 18. In this case, a small-diameter portion having a constant diameter, for example, along the can axis O direction may be formed between the diameter-expanded portion 19 and the diameter-reduced portion 18 after the diameter expansion process.
In the example of this embodiment, the diameter expansion planned portion 19 in FIG. 2 is disposed between the upper end portion (open end portion 11a) and the lower end portion of the can body 11.

  Specifically, in FIGS. 7A, 7 </ b> B, and 11 </ b> B, a punch 40 that fits into the inside of the can body 11 is used as a mold for expanding the diameter. The central axis of the diameter expanding mold 40 is arranged coaxially with the can axis O. Then, by inserting the punch 40 into the inside of the can body 11, the entire region from the opening end portion 11 a of the can body 11 to the diameter expansion scheduled portion 19 is subjected to diameter expansion processing.

  That is, in the diameter expansion process, the diameter expansion mold 40 and the can 10 are moved relatively close to each other in the direction of the can axis O from the state where the diameter expansion mold 40 is disposed above the can 10. While, the diameter expansion mold 40 is entered into the can body 11 of the can 10 from the opening end portion 11a thereof, and the entire region from the opening end portion 11a of the can body 11 to the diameter expansion planned portion 19 is Expand the diameter.

  Specifically, in the outer peripheral surface of the punch 40, it corresponds to a region from the opening end portion 11 a of the can body 11 along the can axis O direction (the central axis direction of the punch 40) to a portion adjacent to the upper portion of the diameter expansion scheduled portion 19. The part to be formed is formed with a constant outer diameter. Further, a die taper portion that gradually increases in diameter as it goes upward is formed in a portion corresponding to the diameter expansion scheduled portion 19 of the can body 11 in the outer peripheral surface of the punch 40.

7 (a) and 7 (b), at the time of diameter expansion processing, the diameter expansion die punch 40 is fitted into the can body 11 while moving (advancing) in the direction of the can axis O with respect to the can 10. Thus, the area of the can body 11 from the opening end portion 11a to the diameter expansion planned portion 19 is subjected to diameter expansion processing.
Further, after the diameter expansion processing, the punch 40 is separated from the can 10 while moving away from the can 10 in the direction of the can axis O (retracted), and the punch 40 is removed from the inside of the can body 11. Return to position.
The portion where the punch 40 expands the can body 11 is above the portion of the can body 11 which has been subjected to the diameter reduction process in the above-described diameter reduction step. The shape of the processed part is maintained.

  In this embodiment, the diameter-expanded portion 19 is subjected to diameter expansion processing a plurality of times while gradually increasing the processing diameter of the diameter expansion mold 40, thereby forming a concave curve in the longitudinal sectional view shown in FIG. Of the constricted portion 17 having a shape, an enlarged diameter portion (a convex curved surface portion 32, a tapered portion 31, and a concave curved surface portion 33) is formed at an upper portion. In each of the plurality of diameter expansion processes, the same diameter expansion process as described above is performed on the entire region from the opening end portion 11a of the can body 11 to the diameter expansion scheduled portion 19.

  As described above, by performing the diameter expansion process a plurality of times, the diameter-expanded portion can be greatly inclined or widely inclined without damaging the can body 11, and the constricted portion 17 is constricted into various shapes. It becomes possible to make it.

As described above, the constricted portion 17 is formed in the can body 11 by performing the constricted portion forming step (the diameter reducing step, the reforming step, and the diameter expanding step).
Specifically, in the present embodiment, in the constriction portion forming step, after the diameter reduction portion 18 of the can body 11 is subjected to diameter reduction processing a plurality of times, the diameter reduction portion corresponding to the diameter reduction expected portion 18 is reformed. Is then applied to the diameter expansion scheduled portion 19 a plurality of times, thereby forming a smooth concave curve that is recessed toward the inside of the can body 11 in a longitudinal sectional view of the can 10 shown in FIG. The constricted portion 17 is formed.

[Necking process]
Next, the can 10 is necked.
In the present embodiment, a necking portion 13 having a smooth inclined shape and a planned flange portion 14 are necked at the opening end portion 11a of the can body 11 using a necking die (diameter for reducing diameter). Molded by processing.

  Specifically, as shown in FIGS. 8A, 8B, and 11C, necking dies 45, 46 are fitted inside and outside the can body 11 of the can 10, and FIG. As shown in FIG. 5, the neck portion 13 is formed by subjecting the opening end portion 11a of the can body 11 to a diameter reduction process that becomes smaller in diameter toward the upper side. Further, by this diameter reduction processing, a cylindrical flange portion 14 having a cylindrical shape is formed above the neck portion 13.

  8A, 8B, and 11C, a punch 45 that fits inside the can body 11 and a die 46 that fits outside the can body 11 are used as a necking die. It is done. The central axes of these necking dies 45 and 46 are arranged coaxially with the can axis O. Then, the opening end 11 a of the can body 11 is necked between the punch 45 and the die 46.

  That is, in the necking step, the necking molds 45 and 46 are relatively spaced in the direction of the can axis O from the state where the necking molds 45 and 46 are spaced apart from the upper part of the can 10. While moving closer, the can body 11 of the can 10 is entered from the opening end portion 11a between the punch 45 and the die 46 of the necking die, and the opening end portion 11a of the can body 11 is reduced in diameter. I will do it.

  In the necking step (diameter reduction step), necking dies 45 and 46 are fitted inside and outside the can body 11, and a can shaft is attached to an opening end portion (a diameter reduction planned portion) 11 a of the can body 11. The diameter-reducing process, which becomes smaller as it goes from the can bottom 12 toward the opening end 11a side (that is, upward) along the O direction, is performed a plurality of times while gradually reducing the machining diameter of the necking dies 45 and 46. Thus, a tapered portion 51 that gradually becomes smaller in diameter as it goes from the can bottom 12 toward the opening end portion 11a along the can axis O direction may be formed on the opening end portion 11a.

  In this necking step, at least the tapered portion 51 is formed at the opening end portion 11a. As shown in FIG. 2, in the necking step, while forming the tapered portion 51, a portion that is adjacently disposed below the tapered portion 51 is formed, and a convex curved surface portion that protrudes toward the outside of the can body 11. 52, and a portion that is adjacently disposed above the tapered portion 51 may be formed to form a concave curved surface portion 53 that is concave toward the inside of the can body 11.

The specific process of reducing the diameter of the open end 11a of the can body 11 with the necking dies 45 and 46 is substantially the same as the diameter reducing process in the above-described constricted part forming process, and therefore detailed here. Description is omitted.
That is, since the necking process is a diameter reducing process similar to the diameter reducing process of the constricted part forming process described above, the reforming process described above is performed as the neck part 13 (convex curved surface part 52, taper) as a subsequent process of the necking process. The neck portion 13 having a desired shape may be formed by applying the portion 51 and the concave curved surface portion 53).

In the necking step, the opening end portion 11a of the can body 11 may be formed by spin flow necking instead of the necking using the necking molds 45 and 46 described above.
The spin flow necking device includes a base pad that adsorbs and supports a can bottom 12 of a can 10 that is pre-necked around the open end 11a of the can body 11 by die-necking, and the can 10 is moved around the can axis O by the base pad. A slide roll that is inserted around the open end 11a of the can 10 while being rotated, an inner roll that is inserted into the can 10 with a smaller diameter than the slide roll, and arranged in the radial direction of the can 10 outside the can. A forming roll (external roll) provided so as to be reciprocally movable.
By this spin flow necking device, the can body 11 of the can 10 is sandwiched between the inner roll and the forming roll, and the diameter thereof is reduced toward the upper end of the opening end portion 11a to form the neck portion 13 and the flange preliminarily portion 14.

[Flanging process]
Next, as shown in FIGS. 9 (a) and 9 (b), the flange flange 14 located at the open end 11 a of the can body 11 is flanged so as to extend radially outward from the upper end of the neck portion 13. An annular flange portion 15 that protrudes and extends along the circumferential direction is formed.

  In the present embodiment, the flange portion 15 is formed by flanging the planned flange portion 14 by spin flow molding. However, the present invention is not limited to this, and the flange portion 15 may be formed by flanging the planned flange portion 14 using a mold (punch) instead of spin flow molding.

  In this manner, the can 10 is manufactured and conveyed to the subsequent process of the flanging process. In this post-process, contents such as a beverage are filled in the inside of the can 10, a can lid is wound around the flange portion 15, and the can body is sealed.

  According to the manufacturing method of the can 10 according to the present embodiment described above, the diameter reduction molds 35 and 36 are processed with respect to the diameter reduction scheduled portion 18 of the can body 11 in the diameter reduction process of the constriction portion forming step. As shown in FIG. 10, an indentation I is formed in the taper portion 21 or the can bottom 12 side of the taper portion 21 is formed by performing the diameter reduction process a plurality of times while gradually reducing the diameter. Even if the sharpened portion S is formed on the adjacent convex curved surface portion 22, in the subsequent reforming process, the tapered portion 21, the convex curved surface portion 22 adjacent to the can bottom 12 side of the tapered portion 21, and Since the concave curved surface portion 23 disposed adjacent to the side opposite to the can bottom 12 of the taper portion 21 is subjected to a remolding process using the reforming dies 55 and 56, the following remarkable effects can be obtained.

That is, by remolding the can body 11 in the reforming step, the surface of the taper portion 21 can be leveled and the indentation I can be eliminated. Moreover, about the convex curve part 22, the shape (convex R shape) can be prepared so that the sharp part S may be rounded and it may become the expected curvature radius R1.
In addition, the re-forming process includes not only the tapered portion 21 and the convex curved surface portion 22 but also the concave curved surface portion 23 adjacent to the side opposite to the can bottom 12 of the tapered portion 21. The meat of the can body 11 can easily flow from 22 toward the concave curved surface portion 23, and the concave curved surface portion 23 can also be adjusted in shape (concave R shape) so as to have an expected radius of curvature R2. The thickness can be secured and the strength can be stabilized.

In addition, in the longitudinal sectional view of the can 10 shown in FIG. 10, an inclination angle θ (tapered portion 21 and can axis O formed between the can body 11 and the tapered portion 21 with a reduced diameter of the can body 11 and the can axis O. In the case where the acute angle between the acute angle and the obtuse angle formed between them is set to be smaller than 20 °, for example, the tapered portion 21 is in a so-called “standing” state, and the can 10 While it becomes easy to ensure the column strength (strength against the load in the direction of the can axis O), the indentation I is more likely to occur.
Even when the tapered portion 21 is in a standing state as described above, according to the present embodiment, the indentation I of the tapered portion 21 can be easily and surely lost. It is possible to maintain the appearance of the can 10 well.
In the present embodiment, the inclination angle θ is preferably 8 to 20 °, and desirably 8 to 10 °.

Further, in the reforming process, the roundness (cylindricity) of the can body 11 is improved by remolding the tapered portion 21, the convex curved surface portion 22 and the concave curved surface portion 23 by the reforming dies 55 and 56. .
That is, in general, the diameter of the can body 11 varies in the circumferential direction around the can axis O even at the same position along the can axis O direction (the difference in diameter occurs due to material anisotropy). However, the above-described variation in the diameter of the can body 11 can be reduced by simultaneously pressing the can body 11 in the entire circumferential direction by the remodeling dies 55 and 56. Thereby, the column strength of the can body 11 can be improved stably.
Further, since the roundness (cylindricity) and the diameter of the can body 11 can be adjusted to the expected values by the reforming process, for example, a diameter expansion process or a flange performed as a subsequent process of the reforming process. The guide diameter portion (especially the concave curved surface portion 23) of the can body 11 serving as a reference at the time of processing can be formed with high accuracy in the forming step (in the diameter expansion step in the example of the present embodiment). Thereby, since the precision of the process to the can body 11 performed in a post process rather than the reforming process is improved, the quality of the shape of the manufactured can 10 can be stably improved, and the can 10 is formed with a beautiful appearance. can do.

In addition, as described in the present embodiment, when the constricted portion 17 having a smaller diameter than other portions of the can body 11 is formed in the can body 11, after the above-described diameter reduction process and the remodeling process. The diameter expansion process is performed. In the diameter expansion process, the diameter expansion mold 40 is fitted inside the can body 11, and the diameter expansion planned portion 19 located between the opening end portion 11 a of the can body 11 and the diameter reduction planned portion 18 is A diameter expanding process is performed so that the diameter increases from the can bottom 12 toward the opening end 11a along the can axis O direction.
Even when such a diameter expansion process is performed, according to the present embodiment, the column strength of the can body 11 is increased as described above, so that the can body 11 may buckle during processing. Suppressed and stable production.

  As described above, according to the present embodiment, the diameter reduction planned portion 18 of the can body 11 is subjected to the diameter reduction processing a plurality of times while gradually reducing the processing diameter of the diameter reduction molds 35 and 36. It is possible to prevent the impression I and the pointed portion S from remaining in the can body 11, to give the can 10 a beautiful appearance, and to increase the column strength.

In the present embodiment, the taper portion 21, the convex curved surface portion 22, and the concave curved surface portion 23 are simultaneously reshaped in the reforming step.
In this case, since the reforming process can be completed by a single process, the ease of manufacturing is improved.

  Further, in the present embodiment, in the diameter reducing step of the constricted portion forming step, a convex curved surface portion that is formed adjacent to the can bottom 12 side of the tapered portion 21 and is convex toward the outside of the can body 11 is formed. In the reforming step, the convex curved surface portion 22 is reshaped so that the curvature radius R1 is larger than the curvature radius of the convex curved surface portion 22 molded in the diameter reducing step in the longitudinal sectional view of the can 10 in the reforming step. Therefore, the following effects can be obtained.

That is, in this case, since the radius of curvature of the convex curved surface portion 22 can be increased step by step for each process, first, in the diameter reducing step, the radius of curvature of the convex curved surface portion 22 to be formed is set to be small. It is possible to reliably prevent the curved surface portion 22 from being wrinkled. Further, in the subsequent reforming step, the convex curved surface portion 22 can be accurately reshaped into a large convex R shape so that the convex curved surface portion 22 has a curvature radius R1 as a product.
In the reforming step, the curvature radius R1 of the convex curved surface portion 22 is set to be large, so that the meat of the can body 11 can easily flow from the convex curved surface portion 22 to the concave curved surface portion 23 during the reshaping. The effect becomes even more remarkable.

  Moreover, in this embodiment, the diameter reduction plan part 18 is arrange | positioned in the can bottom 12 side rather than the opening edge part 11a among the can bodies 11, and diameter expansion is carried out inside the can body 11 as a post process of a remodeling process. The mold 40 is fitted, and the opening end from the can bottom 12 along the can axis O direction to the diameter expansion planned part 19 located between the opening end part 11a of the can body 11 and the diameter reduction planned part 18 Since it includes a diameter expansion process for performing a diameter expansion process that increases in diameter toward the portion 11a, the following effects are achieved.

That is, in this case, the can body 11 is formed with a constricted portion 17 having a smaller diameter than other portions. By forming the constricted portion 17 as described above, the design of the can body can be improved, and the ease of holding (grip property) can be improved, thereby increasing the product value.
According to the present embodiment, since the column strength of the can body 11 is increased as described above, the can body 11 is prevented from buckling during diameter expansion processing.

  Moreover, in this embodiment, the diameter reduction plan part may be arrange | positioned in the opening end part 11a among the can bodies 11, and the neck part 13 is formed in this opening end part 11a by a diameter reduction process and a remodeling process. It may be done.

  In this case, the neck portion 13 can be inclined in a wide range (gradually inclined) in the direction of the can axis O without leaving the indentation I or the pointed portion S on the neck portion 13. Thereby, the design property of a can can be improved and product value can be improved.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

For example, in the above-described embodiment, the constricted portion 17 is formed on the can body 11, and in the diameter reducing step of the constricted portion forming step, the tapered portion 21 is formed on the planned diameter reducing portion 18 of the constricted portion 17, and thereafter In the reforming step of the process, the taper portion 21, the convex curved surface portion 22, and the concave curved surface portion 23 have been described as examples. However, the constricted portion 17 may not be formed.
In this case, the opening end portion 11a of the can body 11 described above is a diameter reduction scheduled portion, and in the necking step (diameter reduction step), the tapered portion 51 is formed on the opening end portion 11a, and in the reforming step of the subsequent step, The taper portion 51, the convex curved surface portion 52, and the concave curved surface portion 53 are reshaped.

  In the above-described embodiment, the taper portion 21, the convex curved surface portion 22, and the concave curved surface portion 23 are simultaneously reshaped in the reforming process, but the present invention is not limited to this. That is, in the reforming step, the taper portion 21, the convex curved surface portion 22, and the concave curved surface portion 23 may be reshaped in a plurality of times.

What is shown in FIGS. 12 to 14 is a modification of the method for manufacturing the can 10 described in the above embodiment. Note that detailed description of the same requirements as the configuration requirements described in the above embodiment is omitted, and only different points will be described below.
In this modification, the reforming process includes a first reforming process for reshaping the convex curved surface portion 22 and a second reforming process for reshaping the concave curved surface portion 23. Further, in at least one of the first reforming process and the second reforming process, the tapered portion 21 is also reshaped. That is, in the above-described embodiment, the “reform process” illustrated in FIG. 3 includes a single remodeling process (reforming process), whereas in the modification illustrated in FIG. The remodeling process ”and the“ second remodeling process ”are performed twice.

  Specifically, in the first remodeling step shown in FIG. 13, a punch 65 that fits inside the can body 11 and a die 66 that fits outside the can body 11 are used as a remodeling mold. It is done. The central axes of the reforming molds 65 and 66 are arranged coaxially with the can axis O. Then, between the punch 65 and the die 66, at least the convex curved surface portion 22 of the tapered portion 21, the convex curved surface portion 22 and the concave curved surface portion 23 of the can body 11 is reshaped and reformed (first processing). Reform processing of).

In the second reforming step shown in FIG. 14, a punch 75 that fits inside the can body 11 and a die 76 that fits outside the can body 11 are used as a remodeling mold. The central axes of the reforming molds 75 and 76 are arranged coaxially with the can axis O. Between the punch 75 and the die 76, at least the concave curved surface portion 23 of the tapered portion 21, the convex curved surface portion 22 and the concave curved surface portion 23 of the can body 11 is reshaped and reformed (second processing). Reform processing of).
In this modified example, the taper portion 21 is also reformed in the second reforming step.
Further, the basic shape of the punches 65 and 75 and the dies 66 and 76 shown in FIGS. 13 and 14 and the operation with respect to the can body 11 are substantially the same as those of the punch 55 and the die 56 described in the above embodiment. Therefore, detailed description is omitted.

  According to the modification shown in FIGS. 12 to 14, since the reforming process includes the first reforming process and the second reforming process, the convex curved surface part 22, the taper part 21, and the concave curved surface part 23 are provided. , Can be remolded step by step. Specifically, first, in the first reforming step, at least the convex curved surface portion 22 of the convex curved surface portion 22 and the tapered portion 21 is reshaped. Then, in the next second reforming step, at least the concave curved surface portion 23 of the tapered portion 21 and the concave curved surface portion 23 is reshaped. In addition, as above-mentioned about the taper part 21, you may remold only in any one process among a 1st reform process and a 2nd reform process. It may be reshaped by dividing it.

In this way, by remodeling the convex curved surface portion 22 and the concave curved surface portion 23 of the can body 11 in separate steps, the processing accuracy of the convex curved surface portion 22 and the concave curved surface portion 23 can be increased. Specifically, with respect to the convex curved surface portion 22, the sharp portion S can be stably rounded, and the shape can be accurately adjusted so as to have an expected radius of curvature. Further, the shape of the concave curved surface portion 23 is accurately adjusted so that the desired radius of curvature is obtained, and the roundness (cylindricity) and the diameter of the can body 11 are expected values. Can do. Further, the taper portion 21 also has an effect that the indentation I can be stably eliminated.
In particular, since the roundness and diameter of the concave curved surface portion 23 can be reshaped with high accuracy by the second remodeling step, the processing accuracy in the diameter expansion step, flanging step, etc. in the post-reform step is particularly remarkable. Will be enhanced.

In the above-described modification, the example in which the reforming process includes two reforming processes (reform processing) of the first reforming process and the second reforming process has been described. Instead, three or more reforming processes are performed. A process may be provided. In this case, for example, the convex curved surface portion 22 is reshaped in the first reforming step, the tapered portion 21 is reshaped in the second reforming step, and the concave curved surface portion 23 is reshaped in the third reforming step. it can.
When the reforming process is provided a plurality of times as described above, the convex curved surface portion 22, the tapered portion 21 and the concave curved surface portion 23 of the can body 11 are directed from the can bottom 12 in the direction of the can axis O toward the opening end portion 11a. Thus, it is preferable to remold in this order.

Moreover, in the manufacturing method of the can 10, it is good also as performing a bottom reform process between a necking process and a flanging process.
In this case, in the bottom reforming step, the bottom reforming process is performed on the can bottom 12 of the can 10 using the bottom reforming mechanism.

  In the above-described embodiment, the can 10 is used for a two-piece can (can body) in which a can lid is wound around the opening end portion 11a. However, the can 10 is not limited to this. Further, it may be used for a bottle can (can body) in which a cap is screwed to the opening end portion 11a.

  In addition, in the range which does not deviate from the meaning of this invention, you may combine each structure (component) demonstrated by the above-mentioned embodiment, a modification, and a remark etc., addition of a structure, omission, substitution, others It can be changed. Further, the present invention is not limited by the above-described embodiments, and is limited only by the scope of the claims.

DESCRIPTION OF SYMBOLS 10 Can 11 Can trunk 11a Open end 12 Can bottom 13 Neck part 18 Diameter reduction plan part 19 Diameter expansion plan part 21, 51 Taper part 22, 52 Convex surface part 23, 53 Concave surface part 35 Punch (mold for diameter reduction) )
36 dies (molds for diameter reduction)
40 punch (expansion mold)
45 Punch (Necking mold, Diameter reduction mold)
46 dies (molds for necking, molds for diameter reduction)
55, 65, 75 Punch (Reform mold)
56, 66, 76 Dies (reform mold)
O can axis R1 radius of curvature

Claims (6)

A method for producing a bottomed cylindrical can having a can body and a can bottom,
A mold for reducing diameter is fitted inside and outside the can body, and the diameter of the can body is reduced toward the opening end side of the can body from the bottom of the can body along the can axis direction. The diameter-reducing process is performed a plurality of times while gradually reducing the diameter of the diameter-reducing mold, whereby the diameter-reduced portion is moved from the bottom to the opening end along the can axis direction. A diameter reducing step for forming a tapered portion that gradually becomes smaller in diameter toward the side,
A remodeling mold is fitted inside and outside the can body, and the taper portion of the can body is disposed adjacent to the can bottom side of the taper portion and protrudes toward the outside of the can body A reforming step of re-forming a convex curved surface portion and a concave curved surface portion that is disposed adjacent to the opposite side of the can bottom of the tapered portion and that is concave toward the inside of the can body. A method for producing a can. It is a manufacturing method of the can according to claim 1,
The reforming process includes
A first reforming step for re-forming the convex curved surface portion;
A second reforming step of re-forming the concave curved surface part,
The method for manufacturing a can, wherein the tapered portion is also reshaped in at least one of the first reforming step and the second reforming step. It is a manufacturing method of the can according to claim 1,
In the reforming step, the taper portion, the convex curved surface portion, and the concave curved surface portion are simultaneously remolded. It is a manufacturing method of the can according to any one of claims 1 to 3,
In the diameter reducing step, a portion of the tapered portion that is disposed adjacent to the bottom of the can is molded to form a convex curved surface portion that is convex toward the outside of the can body,
In the reforming step, the convex curved surface portion is reshaped so that the curvature radius is larger than the curvature radius of the convex curved surface portion formed in the diameter reducing step in the longitudinal sectional view of the can. A method for manufacturing cans. It is a manufacturing method of the can according to any one of claims 1 to 4,
The diameter reduction planned portion is arranged on the can bottom side of the can body, more than the opening end.
As a subsequent step of the reforming step, a diameter expansion mold is fitted inside the can body, and the diameter expansion planned portion located between the opening end portion and the diameter reduction planned portion of the can body, A method for manufacturing a can, comprising: a diameter expansion step of performing a diameter expansion process that increases in diameter as it goes from the bottom of the can toward the opening end along the can axis direction. It is a manufacturing method of the can according to any one of claims 1 to 5,
The planned diameter reduction portion is arranged at the opening end of the can body,
A can manufacturing method, wherein a neck portion is formed at the opening end by the diameter reducing step and the reforming step.

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