WO2018062432A1

WO2018062432A1 - Can, method for manufacturing can, and device for manufacturing can

Info

Publication number: WO2018062432A1
Application number: PCT/JP2017/035340
Authority: WO
Inventors: 平野　茂; 修治山本; 山形　光晴; 楠見　和久
Original assignee: 新日鐵住金株式会社
Priority date: 2016-09-28
Filing date: 2017-09-28
Publication date: 2018-04-05
Also published as: JP6801718B2; TWI651244B; JPWO2018062432A1; TW201813886A

Abstract

[Problem] To further improve the aesthetic appearance of a can. [Solution] A can (1) having a can bottom at a lower part in a can axis direction (C), said can (1) comprising: a can lid (3) which forms the can bottom; a can body (2) which includes a cylindrical body section (21) extending in the can axis direction (C) and a curved section (24) continuing from the lower end of the body section (21) and curving downward at the inner peripheral side of the body section; and a seamed section (4) which is formed by seaming an end part (25) of the curved section (24) on the opposite side from the body section (21) and a rim part (31) of the can lid (3) to each other, thereby joining the can lid (3) and the can body (2) together. The lower end of the seamed section (4) is positioned higher than the lower end of the curved section (24) in the can axis direction (C).

Description

Can body, can body manufacturing method and can body manufacturing apparatus

The present invention relates to a can body, a can body manufacturing method, and a can body manufacturing apparatus.

In the market, metal cans (beverage cans) for beverages filled with beverages such as beer, soft drinks, and coffee are manufactured and sold in a variety of ways and used by general consumers. Such beverage cans can be obtained by, for example, processing a metal thin plate such as aluminum or steel by DI (Drawing and Ironing) molding or DR (Drawing and Redrawing) molding. And the bottom plate (or top plate) are integrally formed. Such beverage cans are called two-piece cans. Such a two-piece can is manufactured by joining a can lid to a can body filled with a beverage by winding or the like. For example, as the can body of the two-piece can, a can in which a neck-in flange is formed at the upper end opening of a thin-walled can body integrally formed from a pressure-proof reinforced bottom plate is used. A can lid with a simple opening called an easy open end smaller in diameter than the can body is used. And a two-piece can is formed by winding the can lid with a simple opening around the neck-in flange of the can body. A beverage can obtained by rolling a thin metal plate into a cylindrical shape to form a can body and joining the bottom plate and the top plate to the can body by winding or the like is called a three-piece can.

Recently, in place of PET bottles and glass bottles, development of bottle cans that have a bottle-like shape and can be resealed with a cap or the like has been underway. Such a bottle can has a high light shielding property against ultraviolet rays and a high sealing property of a gas contained in a beverage as compared with a plastic bottle or a glass bottle. That is, by using a bottle can, the preservability of the beverage as the contents is enhanced. Further, the bottle can has the advantages of being lighter, less likely to break, and easier to recycle than the glass bottle. Therefore, if a bottle can is employ | adopted, it will become possible to suppress the cost which concerns on a container in all the life cycles, such as use and collection | recovery.

Such a bottle can can be realized by a two-piece can, for example. For example, Patent Documents 1 to 3 listed below disclose techniques relating to the structure of the mouth and neck. On the other hand, in Patent Documents 4 to 7 below, a small-diameter mouth / neck portion, a shoulder portion having an inclined surface, and a large-diameter trunk portion are integrally formed, and a bottom lid is tightened at an opening at the lower end of the trunk portion. The technique about the bottle can which seals the contents, such as a drink, is disclosed. Such a bottle can can also be realized by a three-piece can. Specifically, Patent Documents 8 and 9 listed below disclose techniques for a bottle can formed by winding a can body part and a skirt part and a bottom cover of a cap having an inclination, respectively. . In addition, Patent Documents 10 and 11 listed below disclose techniques for folding a winding fastening portion toward the inner peripheral side of a can.

JP 2005-35675 A JP 2006-273385 A JP 2013-227083 A JP 2001-114245 A JP 2002-263745 A JP 2004-168346 A JP 2008-43965 A JP 2001-170729 A JP 2001-170730 A JP 7-33148 A Japanese Patent Publication No. 5-34064

The processing of the mouth and neck and the shoulder is performed from the upper end opening of the two-piece can in Patent Documents 1 to 3, whereas the processing of the mouth and neck and the shoulder is performed from the bottom plate (top plate) of the two-piece can. . From the viewpoint of processing man-hours and technical difficulties in processing of the neck and neck and the shoulder that require a reduction in diameter, the processing method shown in the latter is considered to be more advantageous in manufacturing cans.

However, in the cans disclosed in the above-mentioned Patent Documents 4 to 7, a winding tightening portion for winding and joining the opening at the lower end of the body portion and the bottom lid is provided on the bottom side of the can. If it does so, when the said can is mounted on a flat surface, the said winding fastening part will be exposed. In this case, since it is difficult to decorate the outer peripheral surface of such a tightening part, it is difficult to unify the design of the outer appearance of the outer peripheral surface of the tightening part and the outer peripheral surface of the body part such as the pattern or color. is there. In addition, since the tightening portion is formed by folding the bottom lid and the body portion on the outer peripheral side, it has a structure protruding outward from the lower end of the body portion, so that the appearance of the overall shape of the can is impaired. There is a problem that it ends up.

In addition, in the cans disclosed in Patent Documents 8 and 9, a winding tightening portion that winds the can body portion and the base lid between the can body portion and the skirt portion is arranged, so that the appearance is Although it is less noticeable, the wound part is still visible from the outside. Further, similarly to Patent Documents 4 to 7, a winding fastening portion is provided on the bottom side of the can body so that when the can is placed, the opening is provided at the bottom end of the can body and the bottom lid. There is a problem in that the winding tightening portion is exposed.

It is also conceivable that such a tightening portion is folded into the inside of the can by the technique disclosed in Patent Document 10 to make it difficult to visually recognize the winding portion from the outside. However, the above-mentioned Patent Document 10 specifically describes how to fold the winding fastening portion (for example, what type of folding mold is used and in what process the winding fastening portion is folded back). Is not disclosed. For this reason, even if an attempt is made to simply mold the winding portion so that the winding portion is difficult to visually recognize from the outside, there is a risk of forming defects such as wrinkles or wrinkles in the can body.

Further, in the above-mentioned Patent Document 11, in the can formed by double-wrapping the lid on the opening end of the can body, the top of the double-wrapped seam band is substantially the same surface as the folded end edge of the can body or the It is in a state of being pushed into the inside of the can body from the edge portion. However, in Patent Document 11 described above, the end of the can body widens as the seam band is pushed into the inside of the can body. At this time, the seam band is in contact with the can body on the inner surface of the can body. When the seam band and the can body are in contact with each other, the seam band and the can body are rubbed and a force is applied to the contact portion, so that wrinkles easily enter the contact portion.

Therefore, the present invention has been made in view of the above problems, and the object of the present invention is to make the appearance of the can body more excellent, and to form a can body excellent in the appearance. There is no manufacturing.

In order to solve the above problems, according to one aspect of the present invention, a can body having a can bottom below in the can axis direction, a can lid forming the can bottom, and a cylinder extending in the can axis direction And a can body including a curved body portion that is continuous from the lower end of the body portion and curves so as to protrude downward on the inner peripheral side of the body portion, and provided on the inner peripheral side of the curved portion A winding tightening portion formed by winding an end portion of the curved portion opposite to the body portion and a peripheral edge portion of the can lid, and joining the can lid and the can body. A can body is provided in which the lower end of the winding tightening portion is located above the lower end of the bending portion in the can axis direction.

The can body is connected to the upper side from the body part, and a shoulder part whose diameter decreases as it goes upward from the body part along the can axis direction, and is connected to the upper side from the shoulder part. It may further include a mouth and neck portion having a small diameter and having an opening at the upper end.

The can diameter D ₁ (mm) of the body portion and the diameter D ₂ (mm) of the tightening portion may satisfy the following formula (1).
0.75 × D ₁ ≦ D ₂ ≦ 0.88 × D ₁ Formula (1)

In order to solve the above-mentioned problem, according to another aspect of the present invention, there is provided a method for manufacturing a can body having a bottom of a can in a lower direction in the can axis direction, the fixing step of fixing a workpiece, and the fixing Forming the workpiece, and the workpiece extends in the axial direction of the can and forms a cylindrical body portion that forms a side wall portion of the can body, and is continuous from the lower end of the body portion, Winding an inclined part in which the can diameter decreases from the body part toward the lower side along the can axis direction, a lid body forming the can bottom, a lower end portion of the inclined part, and a peripheral part of the lid body A tightening portion formed by tightening and joining the lid body and the body portion. In the molding step, the lid body and the winding are restrained while restraining the radial movement of the tightening portion. While pushing the fastening part upward in the can axis direction, The inclined portion that is bent along with the bending is formed as a curved portion that protrudes downward on the inner peripheral side of the body portion, and the winding portion is tightened more than the lower end of the curved portion that is formed by bending the inclined portion. A can body manufacturing method is provided in which the lid main body and the winding tightening portion are pushed to a position where the lower end of the portion is above the can axis direction.

In the fixing step, the workpiece is fixed by a die that constrains the outer peripheral surface of the body portion, and in the molding step, a punch disposed on one side in the cylindrical axial direction of the die inside the die, The curved portion is formed by pressing upward in the can axis direction from the bottom side of the can while being in contact with the lid body and the winding fastening portion, and the punch is in contact with the lower surface of the lid body A can lid restraint portion that can be provided, a winding restraint portion having a recess provided on the outer periphery side of the can lid restraint portion and capable of accommodating the winding fastening portion, and provided on an outer periphery side of the winding restraint portion, And a curved molding portion having a molding surface curved so as to protrude downward, wherein the depth of the curved portion of the molding surface is larger than the length of the winding fastening portion in the can axis direction. It may be a punch.

The can diameter D ₁ (mm) of the body portion and the diameter D ₂ (mm) of the tightening portion may satisfy the following formula (1).

0.75 × D ₁ ≦ D ₂ ≦ 0.88 × D ₁ Formula (1)

The workpiece is connected to the upper side from the body part, and the shoulder diameter is decreased from the body part toward the upper side along the can axis direction, and the shoulder part is connected to the upper side from the shoulder part. May further include a mouth and neck portion having a small diameter and having an opening at the upper end.

In order to solve the above problems, according to another aspect of the present invention, there is provided a can body manufacturing apparatus having a can bottom below a can axis direction, the die for fixing a workpiece, and the die And a punch for forming the workpiece together with the die, the workpiece extending in the can axis direction and a side wall portion of the can body A cylindrical body part, a slanted part that extends from the lower end of the body part, and decreases in diameter as it goes downward from the body part along the can axis direction, and a lid body that forms the can bottom And a fastening part that joins the lid body and the body part by fastening the lower end part of the inclined part and the peripheral part of the lid body, and the die comprises the body part By restraining the outer peripheral surface of the workpiece, the workpiece is fixed. The punch is provided with a can lid restraining portion provided so as to be able to contact the lower surface of the lid body, and a winding fastening restraint provided on an outer peripheral side of the can lid restraining portion and having a recess capable of accommodating the winding fastening portion. And a molding surface which is provided on the outer peripheral side of the winding restraint portion and is curved so as to protrude downward in the can axis direction, and the depth of the curved portion in the molding surface is the A punch formed integrally with a curved molding portion that is larger than the length in the can axis direction, and the punch is in contact with the lid main body and the winding tightening portion, and the inner periphery of the die An apparatus for manufacturing a can body is provided that is provided so as to be movable upward along the surface from the bottom side of the can.

According to the can body, when the can body is placed on a flat surface, the tightening portion provided on the inner peripheral side of the bending portion is not visually recognized from the outside. That is, when the can body is placed on a flat surface, the winding tightening portion is shielded by the curved portion, so that the configuration of the winding tightening portion is not included in the appearance of the can body. Therefore, the design of the appearance of the can body can be designed more freely without being bound by the presence of the winding portion.

Further, according to the above can body manufacturing method and manufacturing apparatus, when the can body is placed on a flat surface, the tightening portion provided on the inner peripheral side of the bending portion is not visually recognized from the outside. That is, when the can body is placed on a flat surface, the winding fastening portion is shielded by the curved portion, so that the configuration of the winding fastening portion is not included in the appearance of the can body. Furthermore, when the movement of the tightening portion is constrained in the radial direction, seat bending occurs due to the compressive force in the in-plane direction of the inclined portion, and the curved portion is formed. If it does so, since it will become difficult to pull a winding tightening part to radial direction, the deterioration of the sealing performance by peeling of a joining part can be suppressed, and a molding defect can be prevented.

As described above, according to the present invention, it is possible to improve the appearance of the can body and to produce a can body that is excellent in the appearance without molding defects.

It is a front view which shows an example of a structure of the can 1 which concerns on one Embodiment of this invention. It is the perspective view which looked at the can 1 which concerns on the embodiment from diagonally downward. FIG. 3 is a local cross-sectional view of the can body 1 for explaining the structures of the can lid 3, the tightening portion 4, and the bending portion 24 according to the embodiment. It is a figure for demonstrating an example of the structure of the to-be-processed material 100 immediately after a winding process, and an example of the method of an indentation molding. It is sectional drawing (initial stage) which shows an example of a structure of the manufacturing apparatus 10 of the can which concerns on the embodiment. It is sectional drawing (intermediate stage) which shows an example of a structure of the manufacturing apparatus 10 of the can which concerns on the embodiment. It is sectional drawing (final stage) which shows an example of a structure of the manufacturing apparatus 10 of the can which concerns on the embodiment. It is sectional drawing which shows the structure of the manufacturing apparatus of the can which concerns on the comparative example 1. FIG. It is sectional drawing which shows the structure of the manufacturing apparatus of the can which concerns on the comparative example 2.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

Note that, among the direction axes shown in FIGS. 1A to 6 below, the direction C means the can axis direction of the can body 1 and the direction R shows the radial direction of the can body 1. Hereinafter, in this specification, it describes as can axis direction C and radial direction R. Further, in this specification, the direction indicated by the arrow in the can axis direction C shown in FIGS. 1A to 6 (that is, the mouth-and-neck portion 23 side of the can body 1) is upward, and the direction opposite to the arrow (that is, the can bottom side). ) Is described as the lower part. The can bottom side refers to the can bottom side of the can 1. In this specification, the direction indicated by the arrow in the radial direction R shown in FIGS. 1A to 6 is referred to as the outer peripheral direction, and the direction opposite to the arrow is referred to as the inner peripheral direction. 4A to 6, the can axis direction C and the cylindrical axis direction of the die 50 substantially coincide with each other, and the radial direction R and the radial direction of the die 50 substantially coincide with each other. Therefore, in FIGS. 4A to 6, the cylindrical axis direction and the can axis direction C of the die 50 are collectively referred to as the can axis direction C unless otherwise distinguished, and the radial direction and the radial direction R of the die 50 are described. Are collectively referred to as a radial direction R.

(Configuration of can body)
Drawing 1A and Drawing 1B are figures showing an example of composition of can 1 concerning one embodiment of the present invention. FIG. 1A is a front view of the can body 1 as viewed from the front, and FIG. 1B is a perspective view of the can body 1 as viewed from obliquely below. Moreover, a part of front view shown to FIG. 1A is expressed as a notch figure.

As shown in FIG. 1A and FIG. 1B, the can body 1 includes a bottle-like can body 2, a can lid 3, and a winding fastening portion 4. The can 1 according to the present embodiment has a form of a bottle can that simulates a so-called bottle shape. The material forming the can 1 is, for example, a thin metal such as aluminum, aluminum alloy, or steel. The material and thickness of the sheet metal forming the can body 2 and the can lid 3 are the required strength, rigidity or strength of the can body 1, the type of beverage filled in the can body 1, or the manufacturing cost of the can body 1. It can be appropriately selected depending on the like.

As shown in FIGS. 1A and 1B, the can body 2 has a body portion 21, a shoulder portion 22, a mouth and neck portion 23, and a curved portion 24. In the can body 2, the body portion 21, the shoulder portion 22, The mouth / neck portion 23 and the curved portion 24 are integrally formed. An example of a method for forming the can body 2 will be described later.

The body portion 21 is a cylindrical portion extending in the can axis direction C, and corresponds to the side wall portion of the can body 1. The shape of the body portion 21 is not limited to a simple cylindrical shape as shown in FIGS. 1A and 1B. For example, in order to facilitate the gripping of the can body 1 and / or to make the appearance beautiful, the can diameter of the body portion 21 increases or decreases along the can axis direction C, or the body portion 21. A concave shape, a concavo-convex shape, a groove shape, or the like may be provided in a part of. Further, processing such as embossing or texture may be performed on the surface of the body portion 21.

The shoulder portion 22 is formed continuously from the body portion 21 to the upper side. The shoulder portion 22 is hollow, and has a structure in which the can diameter decreases as it goes upward from the body portion 21 along the can axis direction C. For example, as shown in FIG. 1A, the shoulder portion 22 includes a curved portion that curves outward and inward of the can body 2 and a tapered portion that approaches the can shaft as it goes upward along the can shaft direction C. May be. Of course, the shoulder portion 22 may be configured only by a tapered shape, or may be configured only by a curved shape. Further, a part of the shoulder portion 22 may be formed in a cylindrical shape parallel to the can axis direction C.

The mouth and neck portion 23 is formed continuously with the upper side of the shoulder portion 22. The mouth-and-neck part 23 is a part corresponding to the drinking mouth of the can 1 and has an annular configuration having an opening at the upper end. As shown in FIG. 1A, a curl portion may be provided at the upper end. The curled portion can be formed by providing a flange at the upper end of the mouth-and-neck portion 23 and bending the flange in the outer peripheral direction. A cap that seals the opening at the upper end can be engaged with the curled portion.

Further, a male screw portion (not shown) may be provided on the outer peripheral surface below the upper end of the mouth and neck portion 23. A screw cap can be engaged with the male screw portion. Thereby, resealing of the can 1 is attained.

The curved portion 24 is formed continuously from the lower end of the body portion 21, is bent in the inner peripheral direction of the can body 2, and has a curved groove shape protruding downward in the can axis direction C. That is, the curved portion 24 has an annular groove shape along the outer peripheral edge of the lower end of the can body 2. The detailed configuration of the bending portion 24 will be described later.

The can lid 3 is a member that forms the can bottom of the can 1. The can lid 3 according to the present embodiment includes a disc-shaped lid main body 30 occupying a central portion and a peripheral portion of the lid main body 30. As shown in FIG. 1A, the can lid 3 forms a can bottom by the lid main body 30, and is joined to the can body 2 by the winding tightening portion 4 to seal the opening at the lower end of the can body 2. The outer diameter of the can lid 3 can be appropriately set so that the tightening portion 4 is positioned on the inner peripheral side of the bending portion 24 as will be described later. The thickness of the can lid 3 can be appropriately set according to the strength, rigidity, manufacturing cost, etc. required for the can body 1.

The tightening portion 4 is formed by tightening the can lid 3 and the end portion of the curved portion 24 of the can body 2 opposite to the body portion 21. FIG. 2 is a local cross-sectional view of the can body 1 for explaining the structures of the can lid 3, the tightening portion 4, and the bending portion 24 according to the present embodiment. As shown in FIG. 2, the tightening portion 4 is formed by folding and tightening a peripheral edge portion 31 provided on the outer peripheral side of the lid body 30 of the can lid 3 and an end portion 25 of the bending portion 24. . The winding portion 4 is a joint portion between the can body 2 and the can lid 3, and is formed in an annular shape around the can axis along the circumferential direction of the can body 2 and the can lid 3. Further, the winding portion 4 is provided on the inner peripheral side with respect to the bending portion 24 and so that the lower end 4A of the winding portion 4 is positioned above the lower end 24A of the bending portion 24 in the can axis direction C. Yes.

In addition, a sealing material can be appropriately bonded to the gap between the peripheral edge portion 31 constituting the winding tightening portion 4 and the end portion 25 of the bending portion 24. Such a sealing material may be a known sealing material such as a resin or a composite material. Such a sealing material is applied or formed on the interface between the peripheral edge 31 and the end 25, and the peripheral edge 31 and the end 25 are tightened, whereby the peripheral edge 31 and the end 25 in the tightening part 4 Are fixed, the gap between the two is sealed, and the airtightness of the can 1 is more reliably maintained.

When the can 1 having such a configuration is placed on a flat surface, the lower end 24A of the curved portion 24 comes into contact with the flat surface. That is, the lower end 24 </ b> A of the curved portion 24 is the bottommost portion of the can body 1. At this time, the winding portion 4 is provided on the inner peripheral side with respect to the bending portion 24, and is provided above the lower end 24 </ b> A of the bending portion 24 in the can axis direction C. Accordingly, when the can body 1 is placed on a flat surface, the outer peripheral bending portion 24 shields the inner peripheral winding portion 4, so that the winding portion 4 cannot be visually recognized from the outside. If it does so, the structure of the coiling | tightening part 4 will not be included in the external appearance of the can 1 when the can 1 is mounted on the flat surface. Therefore, the design of the appearance of the can body 1 can be designed more freely without being bound by the presence of the winding part 4. Therefore, it is possible to further improve the appearance of the can body 1.

Further, by making the winding fastening part 4 invisible from the outside, the configuration of the peripheral part 31 of the can lid 3 constituting the outer surface of the winding fastening part 4 can be easily changed without being constrained by the appearance of the can body 1. It becomes possible. For example, the plate thickness of the can lid 3 can be freely changed. Thereby, the plate | board thickness of the can lid | cover 3 can be changed according to the intensity | strength, rigidity, manufacturing cost, etc. which are requested | required of the can body 1, without considering the influence which the can lid | cover 3 has on the external appearance of the can body 1. .

Moreover, when the conventional can body 1 in which the winding tightening portion 4 is exposed on the bottom side of the can falls, a drop impact is directly applied to the winding tightening portion 4, and the joint portion of the winding tightening portion 4 is peeled off. In some cases, the sealing performance of the contents such as beverages may be impaired. According to the present embodiment, when the can body 1 is dropped, the winding fastening part 4 has entered the body part 21 side in the can axial direction C, so that the impact of the drop is directly applied to the winding fastening part 4. It becomes difficult to be transmitted. Therefore, even if the can body 1 falls, the impact force applied to the tightening portion 4 is reduced, so that peeling of the joint portion of the tightening portion 4 is suppressed, and the sealing performance can hardly be impaired.

The depth in the can axis direction C of the curved portion 24 (the length from the lid body 30 to the lower end 24A of the can lid 3) and the width in the radial direction R of the curved portion 24 (the body portion 21 and the winding portion 4) Is not particularly limited. Further, as shown in FIG. 2, the curved portion 24 according to the present embodiment has a curved shape that protrudes downward in the can axis direction C. The curved portion 24 is bent in the inner circumferential direction. If it has the shape which protruded below as a whole, it will not be specifically limited. For example, even if a shape protruding upward in the can axis direction C may partially occur due to the molding process of the bending portion 24, the lower end of the body portion 21 extends to the end portion 25 of the bending portion 24. The configuration of the curved portion 24 is included in the scope of the present invention as long as it has a shape protruding downward in the can axis direction C as a whole.

Furthermore, as a result of investigation by the present inventor, the distance H between the lower end 4A of the winding portion 4 and the lower end 24A of the bending portion 24 shown in FIG. 2 is preferably 0.5 mm or more. If the distance H is 0.5 mm or more, regardless of the shape of the curved portion 24, the winding portion 4 can be reliably shielded so that the outer appearance of the can 1 does not include the configuration of the winding portion 4. It will be possible more reliably.

The configuration of the can 1 according to the present embodiment has been described above.

(Manufacturing method of can body)
Next, an example of the manufacturing method of the can 1 according to the present embodiment will be described. As described above, the can body 1 according to the present embodiment is a so-called two-piece can formed by winding the can lid 3 around the opening end on the bottom side of the can body 2.

The method for manufacturing the can 1 according to the present embodiment will be described in detail. First, in the manufacturing method of the can body 1, a process up to the step of winding the can body 2 and the can lid 3 is described.

In the present embodiment, a blank obtained by punching a thin plate metal is subjected to DI molding to form a cylindrical can body having a top plate and having an open can bottom. And the shoulder part and the mouth-and-neck part are formed by press-molding the top plate side of the can body. At this time, the mouth-and-neck part has a smaller diameter than the body part (the part below the shoulder part) of the can body by such press molding. By pressing the top plate side, regardless of the material of the thin metal plate (for example, steel whose formability is relatively inferior to aluminum), it is possible to reduce the man-hours and suppress material loss, and to reduce the shoulder and neck The part can be formed. Then, by trimming the top surface of the top plate, an opening is formed at the upper end of the mouth-neck portion. In addition, the curled portion is formed by curling the peripheral portion of the opening at the upper end of the formed mouth and neck.

Further, in the present embodiment, an inclined portion that is reduced in diameter toward the inner peripheral direction of the can body is formed at the lower end portion of the body portion. Furthermore, a flange part is formed in the lower end part of the said inclined part. The inclined portion and the flange portion are formed by known neck processing and flange processing. The inclined portion and the flange portion correspond to the curved portion 24 and the end portion 25 described above after the winding process. In addition, the connection part of an inclination part, a trunk | drum part, and a flange part can be suitably provided with a round. The size of the radius is not particularly limited, and is appropriately adjusted according to the diameter reduction ratio (ratio of reduction of the can diameter with respect to the can axis direction C) in the inclined portion.

After forming the inclined part and the flange part, the peripheral part of the can lid and the flange part of the can body are tightened by a tightening process. For the winding process, a known winding process such as double winding is used. Thus, the can lid is wound around the open end of the can body, and the can bottom of the can body 1 is formed by the lid body of the can lid.

Next, a process related to indentation molding of the tightened portion after the tightening process will be described with reference to FIGS. 3 to 4C. FIG. 3 is a diagram for explaining an example of the configuration of the workpiece 100 immediately after the winding process and an example of the indentation method. As shown in FIG. 3, the workpiece 100 includes a can body 200 and a lid body 300, and the can body 200 and the lid body 300 are joined together by a winding portion 400. The can body 200 includes a cylindrical body portion 201, a substantially tapered shoulder portion 202, a substantially annular mouth-and-neck portion 203, a substantially reverse tapered inclined portion 204, and a substantially annular flange portion 205. The material and plate thickness of the workpiece 100 are in accordance with the material and plate thickness of the can 1 described above.

At this point, the winding portion 400 is located on the inner peripheral side of the inclined portion 204 due to the reduced diameter of the inclined portion 204, but is positioned at the bottom of the workpiece 100. In view of this, it is conceivable to perform push molding in which the winding fastening portion 400 (or the lid main body 300) is pushed in the direction of the arrow in FIG. As a result, the winding part 400 is pushed into the body part 201 side of the can body 200, so that the curved part 24 becomes the bottom of the can body 1 as shown in FIG. It is considered that the winding tightening part 400 cannot be visually recognized from the outside when it is placed on the head.

However, as a result of the study by the present inventors, it has been found that simply sealing the winding part 400 or the lid main body 300 deteriorates the sealing performance and moldability of the winding part 400. Specifically, when the winding fastening part 400 or the lid body 300 is simply pushed in, the joint portion between the lid body 300 and the can body 200 can be pulled away from each other. If it does so, the joining location of the winding part 400 in the peripheral part 301 and the flange part 205 will be peeled off. Thereby, the sealing performance of the winding part 400 may deteriorate.

Further, referring to Patent Document 6, the winding portion 400 is formed while the curved portion 24 protruding downward in the can axis direction C is formed by bending the inclined portion 204 in the inner circumferential direction while fixing the can body 200. It is also conceivable that the bend portion 24 is disposed above the lower end of the curved portion 24 in the can axis direction C. However, as a result of the study by the present inventors, the movement of the winding portion 400 in the radial direction R is not constrained, and thus the lid main body 300 and the can body 200 are bent when the inclined portion 204 is bent in the inner circumferential direction. It has been found that the joints of each other are pulled away from each other. Therefore, the sealing performance of the winding part 400 can be deteriorated. Moreover, the location where the bend in the inner circumferential direction of the inclined portion 204 is shifted during bending. It is difficult to form the inclined portion 204 into a desired shape, and the tightening portion 400 is difficult to move upward in the can axis direction C. As a result, the tightening portion 400 is less than the lower end of the bending portion 24. Also, it has been difficult to dispose them upward.

In this way, it is possible to form the can body 1 having a structure in which the winding tightening portion 4 cannot be visually recognized from the appearance without causing molding defects simply by pushing the member on the can bottom side of the workpiece 100. It was difficult.

Therefore, the present inventors diligently studied and came up with the present invention. In the present invention, with the workpiece 100 fixed, the winding portion 400 is pushed upward in the can axis direction C while restraining movement of the winding portion 400 in the radial direction R. Thus, the inclined portion 204 is bent, and a curved portion protruding downward in the can axis direction C is formed on the inner peripheral side of the body portion 201. At that time, the lid main body 300 and the tightening portion 400 are pushed to a position where the lower end of the tightening portion 400 is above the lower end of the curved portion formed by bending the inclined portion 204 in the can axis direction C.

According to such a technique, since the movement of the tightening portion 400 in the radial direction R is restricted, when the lid body 300 and the tightening portion 400 are pushed in the can axis direction C, The joint portion with the can body 200 is hardly pulled in the radial direction R. Thereby, the joining location of the winding part 400 in the peripheral part 301 and the flange part 205 does not peel off, and the sealing performance of the winding part 400 can be maintained.

Further, if the movement of the winding portion 400 in the radial direction R is restricted, the winding portion 400 is hardly pulled in the radial direction R due to the bending of the inclined portion 204 when the inclined portion 204 is bent. Further, by restraining the winding tightening portion 400, it is possible to suppress a shift of a portion where the inclined portion 204 is bent in the inner circumferential direction. Therefore, the inclined portion 204 can be easily formed into a curved portion having a desired shape, and the lower end of the winding fastening portion 400 can be positioned more reliably than the lower end of the curved portion.

Hereinafter, an example of a manufacturing apparatus that realizes a method for manufacturing a can body according to an embodiment of the present invention and an example of the manufacturing method will be described.

4A to 4C are sectional views showing an example of the configuration of the can manufacturing apparatus 10 according to the present embodiment. 4A shows an initial stage of the indentation process by the manufacturing apparatus 10, FIG. 4B shows an intermediate stage of the indentation process, and FIG. 4C shows a final stage of the indentation process. Note that the initial stage of the indentation molding process is a stage before the punch 60 for indentation molding is pushed upward in the cylindrical axis direction of the die 50 (that is, the can axis direction C), and the intermediate stage is the indentation of the punch 60. The final stage means a stage in which the punch 60 has moved a predetermined distance and has been pushed in.

Referring to FIG. 4A, the manufacturing apparatus 10 according to the present embodiment includes a die 50 and a punch 60.

The die 50 is, for example, a cylindrical mold that holds the outer periphery of the workpiece 100. The die 50 fixes the workpiece 100 by restraining the outer peripheral surface of the body portion 201 and the shoulder portion 202 of the workpiece 100 installed in the internal space. For example, when the workpiece 100 is installed on the die 50, the workpiece 100 is held on the die 50 by the outer peripheral surface of the body portion 201 of the workpiece 100 coming into contact with the inner peripheral surface 50 </ b> A of the die 50. The Thereby, the movement to the can axis direction C and radial direction R of the trunk | drum 201 is restrained. The shape, structure, and mechanism of the die 50 are not particularly limited, and any configuration can be applied as long as the outer peripheral surface of the body portion 201 is abutted and restrained.

The punch 60 is a mold for indenting the can bottom side of the workpiece 100 fixed by the die 50. The punch 60 is disposed on one side of the die 50 in the cylindrical axis direction (that is, the can axis direction C) in the inner space of the die 50, and is provided so as to be movable in the vertical direction along the circumferential axis direction. The punch 60 bends the inclined portion 204 directly or indirectly in the inner circumferential direction while pushing the lid main body 300 and the winding fastening portion 400 of the workpiece 100 installed on the die 50 upward in the can axis direction C. Then, the curved part is formed. Specifically, as shown in FIG. 4A, the punch 60 according to the present embodiment includes a can lid restraining portion 61, a winding fastening restraining portion 62, and a curved forming portion 63, which are integrally formed to form the punch 60. To do.

The can lid restraining portion 61 is provided so as to be able to contact the lower surface of the lid main body 300. In the indentation molding, the can lid restraining portion 61 abuts on the lid main body 300, so that the displacement of the lid main body 300 in the radial direction R and the out-of-plane deformation of the lid main body 300 can be suppressed.

The can lid restraining portion 61 is provided at a portion that comes into contact with the lid main body 300 when the workpiece 100 is placed on the punch 60. In the example shown in FIG. 4A, the can lid restraining portion 61 is provided so as to be able to contact the entire surface of the lid main body 300, but the present invention is not limited to such an example. For example, the can lid restraining portion 61 may be provided so as to be able to contact only a part (for example, the outer portion) of the lid main body 300 using the hollow cylindrical can lid restraining portion 61. The outer edge portion of the can lid restraining portion 61 has a shape corresponding to the shape of the boundary portion between the lid main body 300 and the winding fastening portion 400. For example, in the example shown in FIG. 4A, the outer edge portion of the can lid restraining portion 61 forms a rounded shape along the curved surface shape of the boundary portion.

The winding tightening restraining portion 62 is provided on the outer peripheral side of the can lid restraining portion 61 and forms an annular recess that can accommodate the winding tightening portion 400. As shown in FIG. 4A, when the winding tightening portion 400 is accommodated in the recess of the winding tightening restraining portion 62 during the press molding, the movement of the winding tightening portion 400 in the radial direction R is restrained. The position where the concave portion of the tightening restraint portion 62 is provided in the punch 60 is a position facing the tightening portion 400, and can be appropriately adjusted according to the processing position in the radial direction R of the tightening portion 400 in the workpiece 100. . A preferable range of the diameter of the winding part 400 will be described later.

The width of the concave portion of the tightening restraint portion 62 can be appropriately adjusted so as to be substantially the same as the width in the radial direction R of the tightening portion 400 formed by the tightening process. Thereby, the restraint of the movement of the winding part 400 in the radial direction R can be further ensured. In addition, the depth of the concave portion of the tightening restraining portion 62 is not particularly limited, but the depth of the concave portion is from the lid body 300 to the lower end of the tightening portion 400 in order to securely accommodate the winding portion 400 in the concave portion. It is preferable that it is more than length. Thereby, it becomes possible to prevent the molding defect of the lid body 300 in the vicinity of the tightening portion 400 from occurring more reliably. Further, the bottom of the concave portion of the winding restraint portion 62 may not be provided.

The curved forming portion 63 is a portion provided on the outer peripheral side of the winding fastening restraint portion 62 and on the inner peripheral side of the inner peripheral surface 50 </ b> A of the die 50. The curved molding portion 63 has a molding surface 63A for molding the curved portion 24 that contacts the bent inclined portion 204 and projects downward in the can axis direction C. That is, the molding surface 63A is an annular groove having a curved shape corresponding to the curved portion 24, and the cross-sectional shape of the molding surface 63A has a shape that curves so as to protrude downward.

When the punch 60 is pressed upward in the can axis direction C in contact with the workpiece 100, a bending deformation that buckles upward occurs in a part of the inclined portion 204. The location where the bending occurs may be a location that abuts against a portion in the vicinity of the boundary between the curved forming portion 63 and the winding restraint portion 62. As the punch 60 is pushed upward, a portion on the outer peripheral side of the portion where the bending of the inclined portion 204 occurs relatively protrudes below the portion where the bending occurs. Thereafter, the portion on the outer peripheral side of the inclined portion 204 protruding downward comes into contact with the molding surface 63A and is deformed and curved along the molding surface 63A. Thereby, the curved part 24 of the can 1 is formed.

As shown in FIG. 4A, the depth _HA of the curved portion of the molding surface 63A of the curved molding portion 63 (the length in the can axis direction C from the upper surface of the can lid molding portion 61 to the lower end of the molding surface 63A) is The length H _{B in} the can axis direction C of the tightening portion 400 of the workpiece 100 is larger. Thereby, in the can 1 after molding, the lower end of the winding portion 4 is positioned above the lower end 24A of the curved portion 24 in the can axial direction C.

The shape and size of the molding surface 63A are the height of the inclined portion 204 (the length in the can axis direction C from the lower end of the body portion 201 to the lid body 300, that is, the length of the reduced diameter portion), or the tightening. It can be appropriately designed according to the position and size of the part 400.

Next, an indentation forming process using the manufacturing apparatus 10 will be described with reference to FIGS. 4A to 4C.

First, in the initial stage of the indentation molding process shown in FIG. 4A, the body part 201 is restrained by the die 50 to fix the workpiece 100, and the lid body 300 is placed on the punch 60. At this time, the lid main body 300 abuts against the can lid restraining portion 61, and the winding fastening portion 400 is housed in the winding fastening restraining portion 62. In addition, the curve shaping | molding part 63 does not need to contact | abut the inclination part 204 in the initial stage of an indentation shaping | molding process.

Next, in the intermediate stage of the indentation molding process shown in FIG. 4B, the punch 60 moves upward in the can axis direction C along the inner peripheral surface 50A of the die 50, and the lid body 300 and the tightening portion 400 are pushed upward. Meanwhile, the inclined portion 204 is bent. At this time, as shown in FIG. 4B, for example, the contact portion of the inclined portion 204 with the curved forming portion 63 can be bent upward and bent by being pushed by the curved forming portion 63.

In the intermediate stage of this indentation molding process, the movement of the lid main body 300 and the tightening portion 400 in the radial direction R is restrained by the can lid restraining portion 61 and the tightening restraining portion 62, respectively. Then, the winding part 400 is displaced upward while restraining the winding part 400, thereby generating an in-plane compressive force on the inclined part 204. As a result, buckling may occur at the location where the inclined portion 204 is bent. In other words, the bending deformation of the inclined portion 204 can be caused not by direct bending of the inclined portion 204 by the punch 60 but by buckling due to the compressive force in the in-plane direction with respect to the inclined portion 204 due to the restraint of the winding tightening portion 400. If it does so, since the reaction force from the inclination part 204 will be applied to the winding part 400, it will become difficult to apply the tensile force of radial direction R. FIG. Therefore, peeling of the joint part of the winding part 400 can be suppressed, and the sealing performance of the winding part 400 can be maintained. In addition, buckling (that is, bending deformation) in the inclined portion 204 may occur not in the contact portion with the curved forming portion 63 as shown in FIG.

And in the final stage of the indentation molding process shown in FIG. 4C, along the molding surface 63A of the curved molding portion 63 of the punch 60, the inclined portion 204 projects downward and deforms into a curved shape. Such a curved shape is formed in a portion on the outer peripheral side with respect to a portion where the bending deformation of the inclined portion 204 occurs. The inclined portion 204 after such deformation becomes the curved portion 24 in the can body 1. In this final stage, the punch 60 is pushed upward from the can bottom side to a position where the lower end of the winding portion 400 is above the lower end of the curved portion 24 formed from the inclined portion 204 in the can axial direction C. . Thereby, in the can body 1 obtained after the indentation molding process, when the can body 1 is placed on a flat surface, the winding portion 4 may not be visually recognized by the curved portion 24 from the outside.

The final position of the punch 60 in the final stage of the indentation molding process is such that the distance in the can axis direction C between the lower end of the pressed winding portion 4 and the lower end of the formed curved portion 24 is 0.5 mm or more. It is preferable that it is the position which becomes. As described above, if the distance H is 0.5 mm or more, regardless of the shape of the curved portion 24, the winding portion 4 is reliably shielded, and the appearance of the can 1 does not include the configuration of the winding portion 4. It is possible to do so more reliably.

A can having a configuration in which the winding portion 4 is located on the inner peripheral side of the bending portion 24 and the lower end of the winding portion 4 is positioned above the lower end of the bending portion 24 in the can axial direction C through the above indentation molding process. The body 1 can be manufactured.

The configurations of the can lid restraining portion 61, the winding fastening restraining portion 62, and the curved forming portion 63 that form the punch 60 are not limited to the configurations described in FIGS. 4A to 4C. These configurations can be appropriately designed based on the positions, sizes, shapes, and the like of the lid main body 300, the winding portion 400, and the inclined portion 204 of the workpiece 100 that is the object of the forming process.

Further, as a result of further studies by the present inventors, the diameter of the tightening portion 400 (from the can shaft to the position where the can body 200 and the lid main body 300 at the base of the tightening portion 400 contact each other as shown in FIG. 4A). It has been found that a molding defect due to indentation molding can be more reliably suppressed when (twice the length of 2) is a predetermined size. Specifically, Kan径of the body portion 201 (the diameter of the outer circumferential surface of the body 201) and D _1, the diameter of the seaming portion 400 when the D _2, it is preferable to satisfy the following formula (1) . If D ₂ ≧ 0.75 × D ₁ , the generation of wrinkles associated with the effect of work hardening by the diameter reduction processing of the inclined portion 204 can be suppressed. Moreover, the number of diameter reduction steps can be reduced, which is advantageous from the viewpoint of cost. Further, if D ₂ ≦ 0.88 × D ₁ , it is possible to suppress physical interference between the winding portion 400 and the inclined portion 204 when the inclined portion 204 is bent and deformed. 400 and the inclined portion 204 are not rubbed to cause wrinkles, and the forming accuracy of the bending portion 24 can be improved.

0.75 × D ₁ ≦ D ₂ ≦ 0.88 × D ₁ Formula (1)

In the above, the manufacturing method and the manufacturing apparatus 10 of the can 1 which concern on this embodiment were demonstrated.

Next, examples of the present invention will be described. In order to confirm the effect of the present invention, in this example, the performance of the can 1 manufactured by the manufacturing method and the manufacturing apparatus 10 according to the above embodiment was verified. In addition, the following Examples are only performed in order to verify the effect of this invention, and this invention is not limited to the following Examples.

In the present example, the winding part 4 of the can body 1 obtained after the winding part 400 of the workpiece 100 is pushed upward from the can bottom side using the manufacturing method and the manufacturing apparatus 10 according to the above embodiment. The external visibility, peeling of the joint portion, and moldability of the curved portion 24 are evaluated, and the effectiveness of the manufacturing method and the manufacturing apparatus 10 is shown. In this evaluation, the external visibility of the winding part 4 was determined by whether or not the winding part 4 was visible from the outside of the can 1 when the molded can 1 was placed on a flat surface. . The presence or absence of peeling of the joint portion of the winding portion 4 was determined by whether or not peeling of the joint portion between the can lid 3 and the can body 2 of the winding portion 4 was observed. Further, the formability of the bending portion 24 was determined by the presence or absence of wrinkles or wrinkles generated in the bending portion 24.

Test conditions and evaluation results are shown in Table 1 below. As test conditions, the configuration of the punch used, the can diameter D ₁ (mm) of the body portion 201 of the workpiece 100, the diameter D ₂ (mm) of the tightening portion 400, and the tightening portion 400 with respect to the can diameter D ₁ The ratio D ₂ / D _{1 of} the diameter D ₂ and the height H _S (mm) of the inclined portion 204 were used. Here, as described above, the height H _S of the inclined portion 204 is the length in the can axis direction C from the lower end of the body portion 201 to the lid body 300, that is, the length of the reduced diameter portion in the can axis direction C. is there. For cans formed from punches and workpieces satisfying such test conditions, the external visibility of the tightened portion, the presence or absence of peeling, and the formability of the curved portion were evaluated. In addition, the plate | board thickness of the can body 200 and the lid body 300 which comprise the to-be-processed material 100 used by each Example and the comparative example was 0.35 mm, respectively. The material of the workpiece 100 is T2 of JIS G3303 which is a mild steel plate.

In Examples 1 to 5, indentation molding was performed on the workpiece 100 using the punch 60 shown in FIG. 4A. Can lid restraining portion 61, seaming restraining portion 62 and the curving section 63, Kan径_{D 1} of the body portion 201, in accordance with the height _{H S} such diameter _{D 2} and the inclined portion 204 of the seaming section 400, the lid The winding part 400 can be accommodated in the winding restraint part 62 so that the main body 300 can come into contact with the can lid restraining part 61, and the inclined part 204 is formed on the molding surface of the curved molding part 63. Designed appropriately so as to be deformable along 63A.

Further, in Comparative Examples 1 to 3, indentation molding was performed on the workpiece 100 using the punch 600 shown in FIG. A punch 600 shown in FIG. 5 includes only a curved forming portion 601 having a forming surface 601A. That is, when such a punch 600 is used, the curved portion 601 can be directly bent with respect to the inclined portion 204. Further, in Comparative Example 4, indentation molding was performed on the workpiece 100 using the punch 610 shown in FIG. The punch 610 shown in FIG. 6 includes only the can lid restraining portion 611. That is, when such a punch 610 is used, the lid main body 300 is pushed upward from the can bottom side, whereby bending deformation can occur in the inclined portion 204.

The evaluation results will be described with reference to Table 1. For the molded can body 1 according to Examples 1 to 5, when the can body 1 is placed on a flat surface, the winding fastening portion 4 is not visually recognized from the outside, and further, the joined portion of the winding fastening portion 4 It was confirmed that peeling was not confirmed and the sealing property was maintained. In Example 1, although some wrinkles were observed in the curved portion 24 of the can body 1, the wrinkles were visually recognized when the can body 1 was placed on a flat surface because it was formed on the can bottom side. Was not. In Examples 2 to 5, it was confirmed that wrinkles and wrinkles were not observed on the curved portion 24 of the can 1 and that the curved portion 24 formed a shape corresponding to the molding surface 63A.

Incidentally, according to the evaluation results of Examples 3-5, regardless of the height H _S of the inclined portion 204, the can body 1 which is excellent in moldability can be obtained was confirmed.

On the other hand, for the can body 1 after molding according to Comparative Examples 1 to 3, when the can body 1 was placed on a flat surface, the winding portion 4 was visually recognized from the outside, and Separation of the joint portion was confirmed, and the bending portion 24 was not sufficiently formed. This is presumably because the inclined portion 204 was directly bent by the curved forming portion 601, so that the winding portion 4 was pulled in the radial direction R and the joint portion was peeled off. Further, the portion where the inclined portion 204 is bent is not stable, and the winding portion 4 is not sufficiently pushed upward from the can bottom side. Therefore, the forming accuracy of the bending portion 24 is low, and the can body 1 is made flat. It is considered that the winding part 4 was exposed when placed on top.

Furthermore, in the can body 1 according to Comparative Example 4, peeling of the joint portion of the tightening portion 400 was not noticeable as compared with the can body 1 according to Comparative Examples 1 to 3, but was partially observed. In addition, the winding tightening portion 400 and the bent inclined portion 204 interfere with each other, and the winding tightening portion 4 is not pushed in and is exposed when the can body 1 is placed on the flat surface. From this fact, it is considered that the restraint of the tightening portion 400 and the bending deformation of the inclined portion 204 are insufficiently controlled by pushing the lid main body 300 only by the can lid restraining portion 611.

From this embodiment, in order to manufacture the can body 1 in which the tightening portion 4 is not visible from the outside while maintaining the sealing performance of the tightening portion 4, it is in contact with the lid body 300 of the workpiece 100. A forming surface 63A for forming the can lid restraining portion 61 for restraining, the winding fastening restraining portion 62 for housing the winding fastening portion 400 and restraining the movement in the radial direction R, and the bending-deformed inclined portion 204 into a curved shape protruding downward. It has been shown that it is effective to push the workpiece 100 upward from the can bottom side of the workpiece 100 using the punch 60 having the curved forming portion 63 having the above. Further, with the magnitude of the predetermined range an outer diameter D ₂ of the seaming portion 400 to the outer diameter D ₁ of the body portion 201, it is possible to improve the moldability of the bending portion 24 shown It was done.

The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

For example, in the above-described embodiment, the can 1 is in the shape of a bottle having the shoulder 22, but the present invention is not limited to such an example. For example, the can body may be a substantially cylindrical can body. Moreover, in the said embodiment, although the can 1 was a can manufactured by DI shaping | molding, this invention is not limited to this example. For example, the can body may be a can manufactured by DR molding or a so-called three-piece can. Moreover, in the said embodiment, although the can 1 was demonstrated as what is applied to a drink can, the application object of this invention will not be limited if it is a can which fills and holds the content inside. That is, as long as the bottom of the can body is formed by winding with a can lid, the present invention can be applied to any can body regardless of the material, the use of the can body, the size, and the molding method.

DESCRIPTION OF SYMBOLS 1 Can body 2,200 Can body 3 Can lid 4,400 Winding part 10

Manufacturing apparatus

21, 201

Body part

22, 202

Shoulder part

23, 203 Mouth and neck part 24 Bending part 25 End part 30 of bending

part

30, 300

Lid Main body

31, 301 Peripheral part 50 Die 60 Punch 61 Can lid restraint part 62 Winding restraint part 63 Curve forming part 63A Forming surface 100 Work material 204 Inclined part 205 Flange part

Claims

A can body having a can bottom below the can axis direction,
A can lid forming the can bottom;
A cylindrical body extending in the can axis direction, and a can body including a curved portion that extends from the lower end of the body portion and curves so as to protrude downward on the inner peripheral side of the body portion;
Provided on the inner peripheral side of the bending portion, formed by winding an end portion of the bending portion opposite to the body portion and a peripheral portion of the can lid, and the can lid and the can body A winding fastening part,
With
The can body, wherein a lower end of the winding fastening portion is located above the lower end of the bending portion in the can axis direction.
The can body is
A shoulder part that is continuous from the body part to the upper side, and whose can diameter decreases as it goes upward from the body part along the can axis direction,
The neck and neck connected to the upper side from the shoulder, smaller in diameter than the body, and having an opening at the upper end;
The can according to claim 1, further comprising:
The can body according to claim 1 or 2, wherein a can diameter D 1 (mm) of the body portion and a diameter D 2 (mm) of the winding portion satisfy the following formula (1).
0.75 × D 1 ≦ D 2 ≦ 0.88 × D 1 Formula (1)
A method for producing a can body having a can bottom below the can axis direction,
A fixing process for fixing the workpiece;
A molding step of molding the fixed workpiece;
Including
The workpiece is
A cylindrical body portion extending in the can axis direction and constituting a side wall portion of the can body;
An inclined part that is continuous from the lower end of the body part, and whose can diameter decreases from the body part toward the lower side along the can axis direction,
A lid body forming the can bottom;
A winding tightening portion formed by winding the lower end portion of the inclined portion and the peripheral edge portion of the lid main body, and joining the lid main body and the body portion;
Including
In the molding step,
While restraining the movement in the radial direction of the tightening portion, while pushing the lid body and the tightening portion upward in the can axis direction, the inclined portion that is bent along with the pushing is located inside the body portion. Molded as a curved portion protruding downward on the circumferential side,
The can body in which the lid main body and the tightening portion are pushed to a position where the lower end of the tightening portion is in the upper direction in the can axis direction than the lower end of the bending portion formed by bending the inclined portion. Manufacturing method.
In the fixing step,
The workpiece is fixed by a die that restrains the outer peripheral surface of the body part,
In the molding step,
A punch disposed on one side of the die in the cylindrical axial direction inside the die is pushed upward from the bottom of the can in the axial direction of the can while being in contact with the lid main body and the tightening portion. To form the curved portion,
The punch is
A can lid restraining portion provided so as to be able to contact the lower surface of the lid body;
A winding restraint portion provided on an outer peripheral side of the can lid restraint portion and having a recess capable of accommodating the winding fastening portion;
A molding surface provided on an outer peripheral side of the winding restraint portion and curved so as to protrude downward; a depth of the curved portion of the molding surface is larger than a length of the winding fastening portion in the can axis direction; A large curved molding,
The method for manufacturing a can body according to claim 4, wherein the punch is an integrally formed punch.
The can manufacturing method according to claim 4 or 5, wherein a can diameter D 1 (mm) of the body portion and a diameter D 2 (mm) of the winding portion satisfy the following formula (1).
0.75 × D 1 ≦ D 2 ≦ 0.88 × D 1 Formula (1)
The workpiece is
A shoulder part that is continuous from the body part to the upper side, and whose can diameter decreases as it goes upward from the body part along the can axis direction,
The neck and neck connected to the upper side from the shoulder, smaller in diameter than the body, and having an opening at the upper end;
The method for producing a can body according to any one of claims 4 to 6, further comprising:
An apparatus for producing a can body having a can bottom below the can axis direction,
A die for fixing the workpiece,
A punch that is disposed on one side of the die in the cylindrical axial direction inside the die, and molds the workpiece together with the die; and
With
The workpiece is
A cylindrical body portion extending in the can axis direction and constituting a side wall portion of the can body;
An inclined part that is continuous from the lower end of the body part and decreases in diameter as it goes downward from the body part along the can axis direction;
A lid body forming the can bottom;
A winding tightening portion formed by winding the lower end portion of the inclined portion and the peripheral edge portion of the lid main body, and joining the lid main body and the body portion;
Including
The die fixes the workpiece by restraining the outer peripheral surface of the body part,
The punch is
A can lid restraining portion provided so as to be able to contact the lower surface of the lid body;
A winding restraint portion provided on an outer peripheral side of the can lid restraint portion and having a recess capable of accommodating the winding fastening portion;
A molding surface provided on the outer peripheral side of the winding restraint portion and curved so as to protrude downward in the can axis direction; and a depth of the curved portion of the molding surface is the axis direction of the winding portion A curved molded part larger than the length of
Is an integrally formed punch,
The can manufacturing apparatus, wherein the punch is provided so as to be movable upward from the can bottom side along the inner peripheral surface of the die in a state where the punch is in contact with the lid main body and the winding fastening portion. .