TW201738013A - Can and method for forming curled section in can mouth - Google Patents

Abstract

The present invention is a shape for a curled section whereby sealing performance desired for adhesion thereto by a cap can be obtained, and whereby deformation of the curled section by dropping impact is suppressed. A curled section 10 of a can 1 has: a top-end curved section 11 including the top end of a mouth 1D; an outer wall curved section 12, a bottom end 12A of which approaches or comes in contact with a side wall 2 of the mouth 1D, and an upper portion of which is inclined outward with respect to a can axis; an inside connecting curved section 13 having a smaller curvature radius than the curvature radius of the top end curved section 11, the inside connecting curved section 13 being provided on the inside of the top end curved section 11; and an outside connecting curved section 14 having a curvature radius smaller than the curvature radius of the top end curved section 11, the outside connecting curved section 14 being provided on the outside of the top end curved section 11.

Description

Method for forming curl portion of can body and can body mouth portion

The present invention relates to a method for forming a crimp portion of a can body and a can body.

The can body having a mouth is generally used as a container for a liquid container such as drinking water, and a curl portion that is wound into a curled shape is formed in a mouth portion sealed with a lid. In particular, the bottle can be formed by forming a metal plate made of aluminum or an alloy thereof into a bottomed cylindrical body by drawing and shrinking, and then forming a hole in the opening of the bottomed cylindrical body. The neck portion is necked, and a thread forming process and a crimp forming process are performed on the mouth portion.

In the curl portion formed in the mouth portion of the can body, various processing shapes have been proposed in consideration of the sealing property with the seal attached to the lid of the mouth portion.

For example, the conventional technique described in the following Patent Document 1 has a shape in which the curled portion formed by folding the peripheral edge of the opening toward the outer side in the radial direction has an outer side wall portion which is substantially toward the can axis direction of the bottle can. The outer side side convex portion extends from the upper end of the outer side wall portion toward the inner side in the radial direction; and the inner surface side convex portion is further curved toward the inner side in the radial direction from the outer side convex portion, and the outer side wall portion is set to a predetermined length. As described above, the connection portion formed by the extrusion processing into the linear outer surface side wall portion and the outer surface side convex portion is separated from the upper end (the upper end of the mouth portion) of the bottle can.

Further, the conventional technique described in the following Patent Document 2 discloses that the curled portion of the outer turn does not need to be subjected to crimp extrusion processing, and the outer side surface thereof is a curved surface that protrudes outward, and the longitudinal cross-sectional shape of the curled portion becomes Long oval shape.

[First technical literature] [Patent Literature]

Patent Document 1: Japanese Patent Publication No. 2004-217305

Patent Document 2: Japanese Patent Publication No. 2006-188279

In the conventional technique described in Patent Document 1, the crimped portion is formed by a combination of curved flange processing (spin forming) and linear extrusion processing. At this time, the lower end of the outer side wall portion is formed as a free end by linear extrusion processing, and a relatively large gap is formed between the outer peripheral surface of the mouth portion (metal mouth portion) of the bottle can. According to this conventional technique, there is a problem that the state in which the mouth is sealed by the lid after filling the contents in the can body, and the lower end of the outer side wall portion and the outer peripheral surface of the mouth are applied in the case where the drop is applied by applying the drop impact. The gap is deformed by the gap, and the desired sealing property cannot be obtained at the sealing point due to the deformation.

On the other hand, in the conventional technique described in the above-mentioned Patent Document 2, it is not necessary to perform extrusion processing to form a curl portion that is integrally curved, and the lower end of the curled portion is brought close to the outer peripheral surface of the mouth portion. However, in the case where the cross-sectional shape is a vertically long elliptical curl, the shape is not resistant to the drop impact. However, there is a problem that the state in which the mouth is sealed by the cap after filling the contents in the can body, and the impact shape is applied, the cross-sectional shape of the curled portion is deformed by extrusion, and the deformation is caused by the deformation. The desired sealing performance could not be obtained.

An object of the present invention is to solve the problem of the prior art, that is, the object of the present invention is to obtain a shape of a curled portion having a desired sealing performance with respect to adhesion to a cover, and the shape suppresses curling with respect to a drop impact The deformation of the department.

In order to solve such a problem, the can system according to the present invention has the following constituents.

A can body having a mouth portion, and a curling portion is provided on the open end of the mouth portion, wherein the curling portion has an upper end bent portion including an upper end of the mouth portion, an outer wall bent portion, a lower end and the foregoing The side wall of the mouth is close to or abuts, and the upper side is inclined with respect to the axially outer side of the tank; the inner connecting curved portion is disposed at the inner side of the upper end curved portion, and has a radius of curvature smaller than a radius of curvature of the upper end curved portion; and an outer side The connecting curved portion is provided outside the upper end curved portion and has a curvature smaller than a radius of curvature of the upper end curved portion.

Further, the method for forming a curl portion of the mouth portion of the can body according to the present invention is a method of forming a curl portion on the open end of the mouth portion of the can body having the bottom portion, the crotch portion, the shoulder portion and the mouth portion, and is characterized by: The portion below the maximum outer diameter portion of the curled portion is bent and formed by extrusion processing.

In the can body of the present invention having such a feature, the cross-sectional shape of the curled portion has a shape that is resistant to the drop impact. Thereby, as opposed to sticking The shape of the curl portion to obtain the desired sealing performance is obtained by the lid of the mouth portion, and this shape can suppress the deformation of the curl portion with respect to the drop impact.

Further, according to the method of forming a curled portion of the present invention, a portion lower than the largest outer diameter portion of the can curled portion can be formed to have a shape with respect to the drop impact resistance or can be obtained with respect to the lid adhered to the mouth portion. The shape of the desired sealing performance.

1‧‧‧ tank

1A‧‧‧ bottom

1B‧‧‧胴

1C‧‧‧Shoulder

1D‧‧‧ mouth

2‧‧‧ side wall

3‧‧‧ Cover

3A‧‧‧Seal

10‧‧‧ Curling Department

11‧‧‧Upper bending

12‧‧‧Bending of the outer wall

12A‧‧‧Bottom

13‧‧‧Inside connection bend

14‧‧‧Outer joint bending

Fig. 1 is an explanatory view showing an example of the configuration of a can body (an overall configuration view).

Fig. 2 is a longitudinal sectional view showing a curled portion of a can body according to an embodiment of the present invention.

Fig. 3 is a vertical cross-sectional view showing the sealing property of the curled portion and the lid of the can body according to the embodiment of the present invention.

Fig. 4 is an explanatory view showing a method of forming a curled portion in a mouth portion of a can body according to an embodiment of the present invention (Fig. 4(a) shows a state before processing, and Fig. 4(b) shows a form of spin forming. In the middle, Fig. 4(c) shows the forming after the spin forming, and Fig. 4(d) shows the forming process of the extrusion processing.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same reference numerals in the different drawings denote the same functions, and the repeated description in the respective drawings is omitted as appropriate.

Fig. 1 shows an example of the configuration of the can body 1. The can body 1 is, for example, a metal container having a bottom portion 1A, a crotch portion 1B, a shoulder portion 1C, and a mouth portion 1D. An example of the can body 1 is a bottle can. The method of forming the can is as follows. For example, will be made of aluminum alloy, etc. The formed metal plate is punched into a circular shape, and is subjected to a crimping process to obtain a bottomed cylindrical cup member, which is subjected to re-draw processing/retraction processing, and a cylindrical can having a predetermined wall thickness is temporarily obtained. Thereafter, by the necking process, the shoulder portion 1C and the mouth portion are formed by reducing the predetermined length from the open end of the cylindrical can. Further, the welded portion and the threaded portion are formed by the spin processing at the mouth portion, and then the side wall (the side wall 2 to be described later) which is inclined upward toward the upper side is formed by the necking process above the threaded portion, and On the open end above the side wall, the curl portion 10 described below is formed by spin processing, whereby the can body 1 having the shape of the bottle of the mouth portion 1D is obtained.

The curled portion 10 is formed by bending the open end of the mouth portion 1D outward to be processed into a curled portion. The curled portion 10 is formed in a ring shape in substantially the same cross section around the mouth portion 1D.

The curled portion 10 provided in the mouth portion 1D of the can body 1 according to the embodiment of the present invention has a cross-sectional shape as shown in Fig. 2 (in the figure, P1 is an imaginary line parallel to the can axis). That is, the curled portion 10 has the upper end upper end bent portion 11 including the mouth portion 1D and the lower end 12A close to or abuts the side wall 2 of the mouth portion 1D and is inclined outwardly with respect to the can axis (imaginary line P1). 12, the cross-sectional shape is such that the side wall 2 of the mouth portion 1D, the upper end curved portion 11, and the outer wall curved portion 12 have a substantially inverted triangular shape of three sides.

The cross-sectional shape of the curl portion 10 has a shape that is structurally resistant to drop impact. When the specific structure is shown, the inner connecting curved portion 13 is provided inside the upper end curved portion 11, and the outer connecting curved portion 14 is provided outside the upper end curved portion 11, and the curvature radius R2 of the inner connecting curved portion 13 is connected to the outer side. The curvature radius R3 of the curved portion 14 is smaller than that of the upper end curved portion 11 The rate radius R1 is formed to be small, and a corner portion having a substantially inverted triangular shape is formed.

Further, in the curling portion 10, the side wall 2 of the mouth portion 1D on the upper side of the lower end 12A of the outer wall bending portion 12 is inclined inward in the upper direction with respect to the can axis (imaginary line P1). As described above, since the side wall 2 of the mouth portion 1D is inclined, the deflection in the F direction can be received by the inclination. Therefore, the curl portion 10 having such a cross-sectional shape also has high resistance with respect to the partial load.

Further, specifically, in the curl portion 10, it is preferable that the curvature radius of the upper end curved portion 11 and the outer wall curved portion 12 are substantially equal. Accordingly, the substantially inverted triangular shape based on the cross-sectional shape of the curl portion 10 is a substantially equilateral triangle, and has equal resistance with respect to the punching load received from various directions. At this time, the outer connecting curved portion 14 becomes the largest outer diameter portion 14A of the curl portion 10.

Fig. 3 shows an example of a sealing structure of the curl portion 10 in the case where the lid 3 is adhered to the mouth portion 1D of the can body 1. In the case where the cap portion 3 has the cap portion 3 adhered to the mouth portion 1D, the sealing member (liner) 3A which is fitted into the cap 3 by the outer connecting bending portion 14 can form a sealing point, and can be obtained well. Sealing. In this case, by reducing the radius of curvature R3 of the outer connecting curved portion 14 from the radius of curvature R1 of the upper end curved portion 11 and setting it in an appropriate range, it is possible to prevent the seal 3A from being damaged and to obtain the The shape of the curl portion 10 of the desired degree of embedding.

In the case where the can body 1 is in the positive pressure state, the lid 3 is constantly biased to move away from the upper end of the mouth portion 1D. However, depending on the cross-sectional shape of the crimp portion 10, the curved portion 14 is connected from the outside of the sealing point. The lower extending outer wall curved portion 12 is inclined toward the inner side, so that the lower side portion is attached to the outer side of the sealing member 3A, and the connecting curved portion 14 has a locking action for preventing the floating of the cover 3 based on the positive pressure. For the case where the can body is in a positive pressure state, an effective sealing effect can also be obtained.

Fig. 4 shows an example of a method of forming the curl portion 10. Fig. 4(a) shows the open end 1D1 before processing. The opening end 1D1 is subjected to spin forming as shown in Figs. 4(b) and 4(c) as the first stage of processing. Specifically, as shown in FIG. 4( b ), the first spinning mold 20 is pressed from above, whereby the curved flange forming (spin forming) is performed on the opening end 1D1. At this time, the curved shape (curvature radius R1) of the upper end curved portion 11 in the curl portion 10 can be formed by the curved shape 20A of the first spinning mold 20. Then, as shown in FIG. 4(c), the second spinning mold 21 is pressed to form the inner side connecting curved portion 13 formed on the inner side of the upper end curved portion 11. At this time, the curved shape (curvature radius R2) of the inner connecting curved portion 13 can be formed by the curved shape 21A of the second spinning die 21.

Then, as the processing of the second stage, as shown in FIG. 4(d), the reforming tool 22 is abutted from the side, and extrusion processing is performed. The outer wall bending portion 12 of the portion below the maximum outer diameter portion of the curled portion 10 is bent and formed by extrusion processing. At this time, the reforming tool 22 has the profile 22A which is inclined obliquely with respect to the outer side in the upper direction of the rotation center axis, and thus the outer wall bending portion 12 is formed by a part thereof by extrusion processing with respect to the rotation center axis of the reforming tool 22 and A curved forming surface in which the can axis (imaginary line P1) is inclined downward in the downward direction.

Thus, as shown in the prior art, it is known to form the crimp portion 10 itself by a combination of spin forming and extrusion processing, but in the forming method of the present invention, one feature is: in extrusion processing The profile 22A of the reforming tool 22 used is a curved surface that is inclined outward with respect to the upper direction of the rotation center axis. By using such a reforming tool 22, the cross-sectional shape of the curled portion 10 can be set to be relative to the falling The lower impact has an effective generally inverted triangular shape with resistance.

The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the specific configuration is not limited to the embodiments, and the present invention is also included in the present invention without departing from the scope of the invention. Further, in the above-described respective embodiments, as long as there is no contradiction or problem in the object, configuration, and the like, it is possible to combine them with each other.

F‧‧‧ directions

14A‧‧‧Maximum OD

14‧‧‧Outer joint bending

11‧‧‧Upper bending

10‧‧‧ Curling Department

13‧‧‧Inside connection bend

P1‧‧‧ imaginary line

R3‧‧‧ radius of curvature of the outer joint bend 14

R1‧‧‧ radius of curvature of the upper end bend 11

R2‧‧‧ radius of curvature of the inner connecting bend 13

12‧‧‧Bending of the outer wall

12A‧‧‧Bottom

2‧‧‧ side wall

Claims (8)

A can body having a mouth portion, and a curling portion is provided on the open end of the mouth portion, wherein the curling portion has an upper end bent portion including an upper end of the mouth portion, an outer wall bent portion, a lower end and the foregoing The side wall of the mouth is close to or abuts, and the upper side is inclined with respect to the axially outer side of the tank; the inner connecting curved portion is disposed at the inner side of the upper end curved portion, and has a radius of curvature smaller than a radius of curvature of the upper end curved portion; and an outer side The connecting curved portion is provided outside the upper end curved portion and has a curvature smaller than a radius of curvature of the upper end curved portion. The can body according to claim 1, wherein the cross-sectional shape of the curled portion is a substantially inverted triangular shape in which the side wall of the mouth portion, the upper end curved portion, and the outer wall bent portion are three sides. The can body according to claim 1 or 2, wherein an upper side of the side wall of the mouth portion above the lower end of the bent portion of the outer wall is inclined upward with respect to the inner side in the axial direction of the can. The can body according to claim 1, wherein the upper end bent portion and the outer wall bent portion have substantially the same radius of curvature. The can body according to claim 1, wherein the outer connecting curved portion is the largest outer diameter portion of the curled portion. A method for forming a curl portion of a can body mouth portion, wherein a curl portion is formed at an open end of the mouth portion of the can body having a bottom portion, a crotch portion, a shoulder portion, and a mouth portion, It is characterized in that the portion below the maximum outer diameter portion of the curled portion is bent and formed by extrusion processing. A method of forming a curl portion of a can body according to claim 6, wherein the molding surface that is bent and formed by the extrusion processing is formed obliquely with respect to the inner side in the can bottom direction. The method for forming a curl portion of a can body according to the sixth or seventh aspect of the invention, wherein the first step of the processing is performed by forming a curved flange on the open end of the mouth portion by a screw thread of a spinning die. As the second stage after that, the above extrusion processing is performed.