JP2020001704A - Bottle can and method for manufacturing the same - Google Patents

Abstract

To provide a method for manufacturing a bottle can, the method allowing for shortening of a manufacturing process and allowing for manufacturing of a bottle can with excellent design.SOLUTION: A bottle can according to the present invention comprises a cylindrical part, a lower inclined part, an upper inclined part, and a mouth part. A curvature radius of an outer surface of a first connection part connecting the cylindrical part to the lower inclined part is 9 mm or more and 20 mm or less, an angle between a can axis and the lower inclined part is 20° or more and 60°or less, a curvature radius of an outer surface of a second connection part connecting the lower inclined part to the upper inclined part is 3 mm or more and 15 mm or less, and an angle between the can axis and the upper inclined part is 1°or more and 20°or less. When a denotes a length in a can axis direction from a couple part of the first connection part and the cylindrical part to a couple part of the second connection part and the upper inclined part, and b denotes a length in a can axis direction from a lower end part of the upper inclined part to a lower part of the mouth part, 2.0<b/a<4.0, and when d denotes an outer diameter of the mouth part, 0.4<d/c<0.7.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a bottle can in which a metal cap is attached to an opening and is filled with contents such as a beverage, and a method for manufacturing the same.

  2. Description of the Related Art As a container to be filled with contents such as beverages, there is known a container in which a metal cap is attached to an opening of a bottle-shaped can (bottle can) and sealed. A bottle can is generally formed in a bottomed cylindrical shape having a body and a bottom, and a shoulder portion and a diameter-reducing portion are provided on the opening side of the body, the diameter gradually decreasing as going upward, and the diameter-reducing portion is provided. Is provided with a mouth at the upper end. Such a bottle can is formed by subjecting a metal plate (a plate of an aluminum alloy material) to a cupping process (drawing process) and a DI process (drawing and ironing process, Drawing & Ironing) to form a bottomed cylindrical shape having a body and a bottom. The shoulder and the reduced diameter portion are formed by reducing the diameter of the body of the cylindrical can with the bottom.

  As such a bottle can, for example, a bottle can described in Patent Document 1 and a bottle can described in Patent Document 2 are known. Among these, the bottle can described in Patent Literature 1 includes a bottom portion, a body portion, a shoulder portion, a neck portion (a reduced diameter portion), and a mouth portion, and the inclination angle β of the reduced diameter portion is 50 ° to 89 °. (1 ° to 40 ° when the can axis direction is 0 °). Further, the bottle can described in Patent Literature 2 has the same configuration as the bottle can described in Patent Literature 1, and the shoulder is approximately 45 ° from the trunk (when the can axis direction is 0 °, the shoulder is 45 °). °), and the inclination angle of the reduced diameter portion is set to approximately 6 °. The bottle cans described in Patent Literatures 1 and 2 are formed into a tapered smooth shape while sequentially deforming the body of the can by die necking using a plurality of molding dies.

Japanese Patent No. 5323775 JP-T-2017-526591

  However, in the bottle can having the above shape, in order to obtain a smooth shape from the shoulder portion to the neck portion, it is necessary to reduce the amount of processing at one time and perform diameter reduction processing many times. When the number of times of processing increases, it is necessary to arrange a number of molding dies side by side on a production line, and a large installation space is required. This leads to an increase in manufacturing costs.

  The present invention has been made in view of such circumstances, and provides a bottle can manufacturing method and a bottle can that can shorten the manufacturing process and can manufacture a bottle can excellent in design. With the goal.

  The bottle can of the present invention has a cylindrical cylindrical portion, a diameter reduced from the upper end of the cylindrical portion toward the upper side in the can axial direction, a vertical cross section passing through the can axis being a linear lower inclined portion, The upper inclined portion is provided on the upper side of the side inclined portion in the direction of the can axis, and the diameter is reduced toward the upper side in the can axis direction at an angle smaller than the angle of the lower inclined portion with respect to the can axis. Portion, and a mouth portion provided on the upper side of the upper inclined portion in the can axis direction, a radius of curvature of an outer surface of a first connecting portion connecting the cylindrical portion and the lower inclined portion is 9 mm or more and 20 mm or less. The angle of the lower inclined portion with respect to the can axis is not less than 20 ° and not more than 60 °, and the radius of curvature of the outer surface of the second connecting portion connecting the lower inclined portion and the upper inclined portion is not less than 3 mm and not more than 15 mm. The angle of the upper inclined portion with respect to the can axis is 1 ° or more and less than 20 °. The length in the direction of the can axis from the connecting portion between the first connecting portion and the cylindrical portion to the connecting portion between the second connecting portion and the upper inclined portion is a, and the lower end of the upper inclined portion is Assuming that the length in the can axis direction up to the lower end of the portion is b, 2.0 <b / a <4.0, the outer diameter of the cylindrical portion is c, and the outer diameter of the mouth is d. In this case, 0.4 <d / c <0.7.

  In the present invention, when the angle of the lower inclined portion with respect to the can axis is less than 20 °, the lower inclined portion is easily deformed by an axial load, and when it exceeds 60 °, the axial load of the lower inclined portion is reduced and the number of moldings is increased. Invite. A more preferable range is 40 ° or more and 60 ° or less. Further, a more preferable range of the radius of curvature of the outer surface of the first connection portion connecting the upper end portion of the cylindrical portion and the lower inclined portion is 9 mm or more and 12 mm or less. Furthermore, since the radius of curvature of the second connection portion is 3 mm or more and 15 mm or less, the lower inclined portion and the upper inclined portion can be smoothly connected. A more preferred range is 3 mm or more and 8 mm or less. As described above, since the radius of curvature of each of the first connection portion and the second connection portion is set to be small, the length of the lower inclined portion having a vertical cross section passing through the can axis can be increased. On the other hand, if the angle of the upper inclined portion with respect to the can axis is less than 1 °, it becomes almost upright, impairing the design of the bottle can. By setting the angle of the upper inclined portion with respect to the can axis at 1 ° or more and less than 20 °, the upper inclined portion can be easily reformed and the number of times of forming the upper inclined portion can be reduced. A more preferable range is 5 ° or more and 10 ° or less. Furthermore, since b / a is within the above range, it is possible to form an upper inclined portion having a sufficiently long image of the neck with respect to the lower inclined portion, thereby improving the design of the bottle can. A more preferred range is 1.5 <b / a <3.5. In addition, since the d / c is within the above range, the appearance of the bottle can can be made closer to the bottle, and the number of times of forming the upper inclined portion and the lower inclined portion can be reduced. A more preferred range is 0.5 <d / c <0.6. Therefore, the manufacturing process can be shortened, and the design of the bottle can can be improved.

  The method for manufacturing a bottle can according to the present invention is the method for manufacturing a bottle can described above, wherein a step of forming a cylindrical body having a bottomed cylindrical shape, and reducing the diameter of the cylindrical body toward the upper side in the axial direction of the can. By providing a reduced diameter portion forming step of forming the lower inclined portion and the upper inclined portion, the reduced diameter portion forming step includes forming a plurality of diameter reducing dies having different molding surfaces on the cylindrical body. By pressing and relatively moving in the can axis direction, the angle to the can axis is not less than 20 ° and not more than 60 °, and the longitudinal section passing through the can axis forms the lower inclined portion having a linear shape, and the cylindrical portion and the cylindrical portion are formed. The radius of curvature of the outer surface of the first connecting portion that connects to the lower inclined portion is set to 9 mm or more and 20 mm or less, and linearly upward from the upper end of the lower inclined portion through the second connecting portion in the axial direction of the can. Forming a lower inclined portion for forming an elongated small cylindrical portion; and forming the lower inclined portion. By pressing a plurality of diameter reducing dies having different diameters of the forming surface against the outer surface of the small cylindrical portion formed by the forming process and relatively moving in the direction of the can axis, the longitudinal section passing through the can axis is directed upward. A temporary forming portion forming step of forming a step-shaped temporary forming portion to be reduced in diameter, and a plurality of diameter reducing dies having different forming surface diameters on the outer surface of the temporary forming portion formed in the temporary forming portion forming step. By pressing and relatively moving, the temporary molding portion is smoothed to form the upper inclined portion, and the radius of curvature of the outer surface of the second connecting portion connecting the lower inclined portion and the upper inclined portion is 3 mm. And a reforming step of making the thickness not less than 15 mm.

  In the present invention, in the lower inclined portion forming step, the vertical section passing through the can axis has an angle with respect to the can axis of the linear lower inclined portion within the above range, and the radius of curvature of the outer surface of the first connection portion is 9 mm or more and 20 mm or more. Since the size is reduced as follows, the force generated in the step of reducing the diameter of the small cylindrical portion performed in the temporary forming portion forming step can be supported by the linear lower inclined portion and the first connection portion. . For this reason, the lower inclined portion and the first connecting portion can be prevented from being deformed by the temporary forming portion forming step and the reforming step, and the reforming of the lower inclined portion and the first connecting portion after the reforming step can be eliminated. Therefore, the manufacturing process can be shortened, and a bottle can with excellent design can be manufactured.

  ADVANTAGE OF THE INVENTION According to this invention, while shortening a manufacturing process, it can manufacture a bottle can excellent in design.

It is the front view which made the half of the container using the bottle can manufactured by the manufacturing method of the bottle can concerning the embodiment of the present invention into the longitudinal section which passes along the can axis. It is a schematic diagram which shows the process of forming a cup and forming a cylindrical body in order in the manufacturing method of the bottle can of the said embodiment, and is a front view which made the longitudinal section which passes along a can axis | shaft about the right half. It is a front view of a bottle can manufacturing device. FIG. 4 is a sectional view taken along line AA of FIG. 3. It is sectional drawing which shows the intermediate molded object after a lower inclined part formation process. It is sectional drawing which shows the intermediate molded body after an upper part formation process. It is sectional drawing which shows the intermediate molded object after a reforming process. It is a front view showing a bottle can according to an example of the present invention and a comparative example.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a front view of a bottle can 1 manufactured by the method for manufacturing a bottle can according to one embodiment of the present invention, and is a half cross-sectional view in which the right half is a cross section passing through a can axis O. The bottle can 1 is used as a container for accommodating a beverage or the like by attaching a cap (not shown) to the opening end. 2 to 7 are explanatory views showing each step of the method for manufacturing a bottle can of the present embodiment. Among these, FIG. 2 is a schematic view sequentially showing steps from forming a cup to forming a cylindrical body 41, FIGS. 3 and 4 are front and sectional views of a bottle can manufacturing apparatus, and FIGS. Shows a cross-sectional view for explaining the reduced diameter portion forming step.

  The bottle can 1 is made of a thin metal such as aluminum or an aluminum alloy, and has a bottomed cylindrical shape having a cylindrical body (wall) 10 and a dome-shaped bottom (bottom) 20 as shown in FIG. Is formed. As shown in FIG. 1, the body 10 and the bottom 20 are arranged coaxially with each other, and in this embodiment, the common shaft will be referred to as a can shaft O.

  In the direction along the can axis O (the can axis O direction), a direction from the opening end 10a of the body 10 toward the bottom 20 is defined as a downward direction, and a direction from the bottom 20 toward the opening end 10a is defined as an upward direction. In the following description, it is assumed that the vertical direction is determined similarly to the directions shown in FIGS. 1 to 3, 5, and 6. Also, a direction orthogonal to the can axis O is called a radial direction, and of the radial directions, a direction approaching the can axis O is radially inward (inward), and a direction away from the can axis O is radially outward ( Outside). Further, the direction of orbit around the can axis O is defined as a circumferential direction.

  As shown in FIG. 1, the body portion 10 has a cylindrical portion 11 formed in a cylindrical shape on the bottom portion 20 side, and goes upward from the upper end portion of the cylindrical portion 11 in the can axis O direction (opening end portion 10a side). A lower inclined portion 13 having a reduced diameter and a straight section passing through the can axis O is linear, a first connecting portion 12 connecting the cylindrical portion 11 and the lower inclined portion 13, and a can shaft of the lower inclined portion 13. The upper inclined portion 15 is provided on the upper side in the O direction, and has a smaller diameter than the angle of the lower inclined portion 13 with respect to the can axis O toward the upper side in the can axis O, and the vertical cross section passing through the can axis O is linear. A second connecting portion 14 connecting the lower inclined portion 13 and the upper inclined portion 15; and a mouth portion 16 provided on the upper side of the upper inclined portion 15 in the can axis O direction.

  As shown in FIG. 1, the inclination angle θ1 of the lower inclined portion 13 with respect to the can axis O is set to 20 ° or more and 60 ° or less, and the inclination angle θ2 of the upper inclined portion 15 with respect to the can axis O is 1 °. At least 20 ° is set. More preferably, the inclination angle θ1 is set to 40 ° or more and 60 ° or less, and the inclination angle θ2 is set to 5 ° or more and less than 10 °. That is, the inclination angle θ1 of the lower inclined part 13 is set to an angle larger than the inclination angle θ2 of the upper inclined part 15, and the upper inclined part 15 stands more in the direction of the can axis O than the lower inclined part 13. It is formed in a shape. The cylindrical portion 11, the first connecting portion 12, the lower inclined portion 13, the second connecting portion 14, and the upper inclined portion 15 each have an annular shape extending over the entire circumferential direction of the body portion 10.

  The cylindrical portion 11, the first connecting portion 12, the lower inclined portion 13, the second connecting portion 14, and the upper inclined portion 15 are smoothly connected to each other and form a step between each other. Connected smoothly without having to. Specifically, in the vertical cross-sectional view shown in FIG. 1, the first connection portion 12 is formed in a convex curved shape that is convex outside (radially outward) and upward of the body portion 10. The upper end of the cylindrical portion 11 and the lower end of the lower inclined portion 13 are connected by one connection portion 12. Further, the second connection portion 14 is formed in a concave curved surface that is concave toward the outside (radially outside) and downward of the trunk portion, and the upper end portion of the lower inclined portion 13 is formed by the second connection portion 14. And the lower end of the upper inclined portion 15 are connected. The radius of curvature R1 of the outer surface of the first connecting portion 12 is set to 9 mm or more and 20 mm or less, and the radius of curvature R2 of the outer surface of the second connecting portion 14 is set to 3 mm or more and 15 mm or less. More preferably, the radius of curvature R1 of the outer surface of the first connection portion 12 is 9 mm or more and 12 mm or less, and the radius of curvature R2 of the outer surface of the second connection portion 14 is 3 mm or more and 8 mm or less.

  In addition, the mouth portion 16 disposed on the upper portion of the body portion 10 includes a large-diameter portion 161 that is once expanded at the upper end of the upper inclined portion 15, a screw portion 162 formed at the upper end of the large-diameter portion 161, and a screw portion 162. And a curl portion 163 formed at the open end 10a at the upper end of the portion 162. As described above, the mouth 16 is opened to the outside by the opening end 10a, and contents such as beverages are filled into the inside of the bottle can 1 through the mouth 16. By attaching a cap (not shown) to the mouth 16, the contents filled inside the bottle can 1 are sealed.

  In addition, the bottom 20 of the bottle can 1 is located on the can axis O, and is formed so as to bulge upward (inside the body 10). And a heel portion 22 connecting the lower portion of the body 10 to the lower portion. In addition, the connection portion between the dome portion 21 and the heel portion 22 is provided on the grounding surface (in such a manner that the bottle can 1 is in the upright posture (the posture in which the opening end 10a of the body 10 is directed upward as shown in FIG. 1). The ground portion 23 is in contact with the ground surface when placed on the mounting surface). The grounding portion 23 protrudes downward at the bottom portion 20 and has an annular shape extending in the circumferential direction.

  The bottle can 1 formed in this manner has a length in the can axis direction from a connecting portion between the first connecting portion 12 and the cylindrical portion 11 to a connecting portion between the second connecting portion 14 and the upper inclined portion 15, Assuming that the length in the axial direction of the can from the lower end of the upper inclined portion 15 to the lower end of the mouth 16 is b, the range is set to 2.0 <b / a <4.0. More preferably, the range is 1.5 <b / a <3.5. By setting b / a within the above range, a sufficient neck length effect of the bottle can 1 can be obtained as the upper inclined portion 15 having a sufficiently long image of the lower inclined portion 13. Further, when the outside diameter of the cylindrical portion 11 is c and the outside diameter of the mouth portion 16 is d, the range is set to 0.4 <d / c <0.7. More preferably, the range is 0.5 <d / c <0.6. By setting d / c within the above range, the appearance of the bottle can is made closer to the bottle. For example, when the numerical values of b / a and c / d are within the above ranges, a is set to 10 mm to 30 mm, b is set to 20 mm to 70 mm, c is set to 55 mm to 60 mm, and d is set to 26 mm to 40 mm.

  As an example of various dimensions other than the above of the bottle can 1 configured as described above, the original plate thickness of the bottle can 1 before molding is 0.250 mm to 0.500 mm. The outer diameter e of the upper end of the lower inclined portion 13 is 40 mm to 55 mm, the outer diameter f of the upper end of the upper inclined portion 15 is 26 mm to 40 mm, and the length g of the cylindrical portion in the direction of the can axis O is 70 mm to 80 mm. The length h of the bottom portion 20 in the direction of the can axis O is 5 mm to 10 mm, and the length i of the bottle can 1 in the direction of the can axis O (the height of the bottle can 1) is 150 mm to 180 mm. However, the above dimensions are not limited to the above numerical ranges.

  The bottle can 1 having the lower inclined portion 13 and the upper inclined portion 15 is manufactured by a manufacturing method described below. The method for manufacturing the bottle can 1 includes a tubular body forming step, a reduced diameter part forming step, and a mouth part forming step.

[Tube forming step]
First, a relatively large-diameter shallow cup 40 is formed as shown in FIG. 2A by punching and drawing an aluminum plate material such as an aluminum alloy, and then drawing and ironing the cup 40 again. By adding (DI processing), as shown in FIG. 2B, a bottomed cylindrical body 41 having a predetermined height is formed, and the upper end thereof is trimmed and trimmed. By this DI processing, the bottom of the cylindrical body 41 is formed into the shape of the bottom 20 as the final bottle can 1.

[Configuration of bottle can manufacturing equipment]
Next, the bottle can 1 is manufactured by, for example, the bottle can manufacturing apparatus 501 shown in FIGS. Next, the bottle can manufacturing apparatus 501 will be described. The bottle can manufacturing apparatus 501 is for processing the cylindrical body 41 formed as described above into a bottle can 1 having a final shape, and the shape of the can changes according to the progress of the processing. However, in the following, in the case where the shape of the bottomed cylindrical can is not particularly limited from the cylindrical body 41 to the bottle can 1, the intermediate can 42 will be described. In the following, description will be given using the same reference numerals as the body 10 and the bottom 20 of the bottle can 1 for the body and the bottom of the intermediate molded body 42.

  The bottle can manufacturing apparatus 501 includes a work holding portion 511 that holds a plurality of intermediate molded bodies 42 with the direction of the can axis O arranged horizontally, and a plurality of molding tools that perform various molding processes on the intermediate molded bodies 42. A tool holding unit 513 that holds the 512 and a drive unit 514 that drives both the holding units 511 and 513 are provided. The work holding side of the work holding part 511 holding the intermediate molded body 42 and the tool holding side of the tool holding part 513 holding the forming tool 512 are arranged to face each other.

  The work holding portion 511 has a configuration in which a plurality of holding devices 517 for holding the intermediate molded body 42 are annularly arranged along the circumferential direction on a surface of the disk 516 supported by the support shaft 515 facing the tool holding portion 513. Have been. When the disk 516 is intermittently rotated about the support shaft 515 by the drive unit 514, the bottom of the intermediate molded body 42 supplied from the supply unit 518 via the supply-side star wheel 519 is placed on the holding device 517 by the holding unit 517. The pieces are held individually and conveyed in the circumferential direction of the disk 516. The intermediate molded body 42 is formed by each forming tool 512 of the tool holding unit 513 during the transportation by the disk 516, and is sequentially discharged to the discharge unit 611 via the discharge-side star wheel 601 as the formed bottle can 1. .

  The tool holding unit 513 has a plurality of various forming tools 512 arranged in an annular shape along the circumferential direction on a surface of the disk 613 supported by the support shaft 612 facing the work holding unit 511, and the disk 613 is supported by the driving unit 514. It is configured to advance and retreat in the axial direction of the shaft 612. The support shaft 612 is provided coaxially with the support shaft 515 inside the support shaft 515.

  The tool holding portion 513 includes a plurality of dies for reducing the diameter of the opening of the intermediate molded body 42 (neck-in processing), a tool for forming a curl portion 163 for forming the curl portion 163, and the like. A plurality of forming tools 512 for performing processing according to each processing stage are provided. These forming tools 512 are annularly arranged on the disk 613 in the process order in the circumferential direction.

  The intermittent rotation stop position of the work holding portion 511 (disk 516) about the axis of the support shaft 515 as the center of rotation is such that the can shaft O of each intermediate formed body 42 whose opening is directed toward the tool holding portion 513 is formed by each can. The setting is made so as to coincide with the central axis of the tool 512. Then, due to the intermittent rotation of the disk 516 by the drive unit 514, each intermediate molded body 42 is rotationally moved to a position facing each molding tool 512 for the next process, and the next stage of processing is performed.

  That is, when the tool holding unit 513 moves forward and the work holding unit 511 and the tool holding unit 513 approach each other, each forming tool 512 performs a process corresponding to each process on the intermediate molded body 42, and the both holding units 511 are provided. , 513 are separated from each other, the workpiece holder 511 is rotated so that the forming tool 512 of the next process faces each intermediate formed body 42. As described above, the operations in which the holding portions 511 and 513 approach each other to perform processing, and separate and rotate are repeated, so that the first connection portion 12, the lower inclined portion 13, and the second connection portion are connected to the intermediate molded body 42. The part 14, the upper inclined part 15, and the mouth part 16 are sequentially formed, and the bottle can 1 is formed.

  Next, a method of manufacturing the bottle can 1 using the bottle can manufacturing apparatus 501 will be described in detail in the order of steps. This bottle can manufacturing apparatus 501 is provided with a tool holding portion 513 with respect to the upper end portion of the cylindrical body 41 formed to the state shown in FIG. 2B by drawing and ironing (DI forming) of a thin plate of an aluminum alloy or the like. While sequentially using the plurality of forming tools 512 arranged in the circumferential direction, the forming tool 512 is moved along the direction of the can axis O to perform die necking, so that the cylindrical body 41 is moved from the intermediate position in the height direction of the cylindrical body 41. The diameter of the portion is reduced, and the first connecting portion 12, the lower inclined portion 13, the second connecting portion 14, and the upper inclined portion 15 are sequentially formed. That is, the bottle can manufacturing device 501 executes the reduced diameter portion forming step.

[Reduced diameter forming process]
In addition, the reduced diameter portion forming step includes the first connecting portion 12, the lower inclined portion 13, and a small cylindrical portion linearly extending upward from the upper end of the lower inclined portion 13 in the can axis direction via the second connecting portion 14. 150, a step of forming a step-shaped temporary forming section 15a whose diameter decreases toward the upper side after the step of forming the lower inclined section, and a step of forming a temporary forming section 15a after the step of forming the temporary forming section. A reforming step of reforming the molding portion 15a to form the second connection portion 14 and the upper inclined portion 15.

[Lower inclined portion forming step]
In the lower inclined portion forming step, the cylindrical body 41 formed up to the state shown in FIG. 2B is provided with a plurality of shrinkage parts having annular forming surfaces having different working diameters indicated by two-dot chain lines in FIG. By pressing the diameter mold 70 (die-necking mold) in the order of the processing diameter and moving relatively in the direction of the can axis O, the angle with respect to the can axis O is not less than 20 ° and not more than 60 °. The lower cross-section 13 having a straight vertical cross section is formed, and the radius of curvature R1 of the outer surface of the first connection portion 12 connecting the cylindrical portion 11 and the lower slope 13 is set to 9 mm or more and 20 mm or less. A small cylindrical portion 150 linearly extending upward from the upper end of the side inclined portion 13 in the can axial direction via the second connecting portion 14 is formed. In addition, the shape shown in FIG. 5 is the intermediate molded body 42 in which the first connection portion 12, the lower inclined portion 13, the second connection portion 14, and the small cylindrical portion 150 are formed.

[Temporary molded part forming step]
In the temporary forming portion forming step, a plurality of (for example, four) diameter reducing dies having annular forming surfaces having different working diameters are formed on the intermediate formed body 42 having the shape shown in FIG. By pressing from the large side and relatively moving in the direction of the can axis O, a step-shaped temporary forming portion 15a is formed in which the longitudinal section passing through the can axis O is reduced in diameter as going upward. In this temporary forming portion forming step, since the four diameter reducing dies are pressed from the side of the forming surface having the larger processing diameter, the temporary forming portion 15a is, for example, a four-step stair-like shape as shown in FIG. Formed. Further, in the temporary forming portion forming step, an opening cylindrical portion 16a extending linearly upward from the upper end of the temporary forming portion 15a along the can axis O and having a smaller diameter than the small cylindrical portion 150 is also formed. .

[Reform process]
In the reforming step, a plurality (for example, three) of diameter reducing dies having annular forming surfaces having different processing diameters are pressed against the outer surface of the temporary forming portion 15a of the intermediate formed body 42 having the shape shown in FIG. By relatively moving, the temporary forming portion 15a is smoothly reformed to form the upper inclined portion 15 having an angle with respect to the can axis O of 1 ° or more and less than 20 ° and a straight cross section passing through the can axis O. At the same time, the radius of curvature R2 of the outer surface of the second connecting portion 14 connecting the lower inclined portion 13 and the upper inclined portion 15 is set to 3 mm or more and 15 mm or less.

  Here, since the angle with respect to the can axis O of the upper inclined portion 15 is as small as 1 ° or more and less than 20 °, for example, in order to obtain such formation without performing the reforming process, the amount of one diameter reduction is required. It is necessary to reduce the size and to use a large number of diameter reducing dies to gradually mold. On the other hand, in the present embodiment, the temporary molding portion 15a is formed using the four diameter reducing dies, and then the temporary molding portion 15a is reformed using the three diameter reducing dies. The part 15 is formed. That is, in the manufacturing process of the present embodiment, it is possible to reduce the number of the use of the diameter reducing mold compared to the conventional manufacturing process.

  In the lower inclined portion forming step, the radius of curvature R1 of the outer surface of the first connection portion 12 is reduced to 9 mm or more and 20 mm or less, so that the diameter of the small cylindrical portion 150 reduced in the temporary forming portion forming step is reduced. The force generated during the process can be supported by the linear lower inclined portion 13 and the first connection portion 12. Therefore, the lower inclined portion 13 and the first connecting portion 12 can be suppressed from being deformed by the temporary forming portion forming step and the reforming step, and the reforming of the lower inclined portion 13 and the first connecting portion 12 after the reforming step is unnecessary. And

[Mouth forming step]
Further, as shown in FIG. 1, a large-diameter portion 161 having a diameter larger than the upper end of the upper inclined portion 15 is formed in the cylindrical portion 16a for the mouth of the intermediate molded body 42 thus formed. After the large diameter portion 161 is formed, a screw portion 162 to which a screw portion (not shown) of the cap is screwed is formed. Finally, curling is performed on the upper end of the mouth cylindrical portion 16a to form a curled portion 163, and the bottle can 1 having the mouth 16 is manufactured.

  In addition, the inside of the bottle can 1 manufactured in this manner is filled with contents such as beverages, and a cap (not shown) is wound around the mouth portion 16 to produce a sealed container. .

  In the bottle can 1 according to the present embodiment described above, since the angle of the lower inclined portion 13 with respect to the can axis O is 20 ° or more and 60 ° or less, the deformation due to the axial load is suppressed, and the increase in the number of moldings is suppressed. it can. In addition, the radius of curvature R1 of the outer surface of the first connection portion 12 that connects the upper end portion of the cylindrical portion 11 and the lower inclined portion 13 is 9 mm or more and 20 mm or less. Further, since the radius of curvature R2 of the second connecting portion 14 is 3 mm or more and 15 mm or less, the lower inclined portion 13 and the upper inclined portion 15 can be smoothly connected. As described above, since the radius of curvature of each of the first connection portion 12 and the second connection portion 14 is set to be small, the length of the lower inclined portion 13 can be increased. In addition, by making the angle of the upper inclined portion 15 with respect to the can axis O from 1 ° to less than 20 °, the upper inclined portion 15 can be easily reformed and the number of times of forming the upper inclined portion 15 can be reduced. Further, since b / a is within the above range, the upper inclined portion 15 having a sufficiently long image of the lower inclined portion 13 can be obtained, and the design of the bottle can 1 can be enhanced. . In addition, since the d / c is within the above range, the appearance of the bottle can 1 can be made closer to the bottle, and the number of times of forming the upper inclined portion 15 and the lower inclined portion 13 can be reduced. Therefore, the manufacturing process can be shortened, and the design of the bottle can 1 can be improved.

  In the method of manufacturing the bottle can 1 of the present embodiment, in the lower inclined portion forming step, the angle of the lower inclined portion 13 with respect to the can axis O whose vertical cross section passing through the can axis O is linear is set within the above range, Since the radius of curvature R1 of the outer surface of the first connection portion 12 is reduced to 9 mm or more and 20 mm or less, the force generated during the step of reducing the diameter of the small cylindrical portion 150 performed in the step of forming the temporary formed portion is reduced to the linear shape. Can be supported by the lower inclined portion 13 and the first connection portion 12. Therefore, the lower inclined portion 13 and the first connecting portion 12 can be suppressed from being deformed by the temporary forming portion forming step and the reforming step, and the reforming of the lower inclined portion 13 and the first connecting portion 12 after the reforming step is unnecessary. It can be. Therefore, the manufacturing process can be shortened, and the bottle can 1 having excellent design can be manufactured.

  The present invention is not limited to the configuration of the above-described embodiment, and various changes can be made in the detailed configuration without departing from the gist of the present invention. For example, as a bottle can, a cylindrical body 41 with a bottom was formed in advance, and the opening end thereof was formed. However, the cylindrical body also includes one having no bottom, and after forming the reduced diameter portion, Alternatively, a separately formed bottom portion may be wound around the body of the cylindrical body.

  Next, the effects of the present invention will be demonstrated with reference to examples of the present invention. In the following examples and comparative examples, the process of forming the reduced diameter portion with respect to the cylindrical body having the shape shown in FIG. Specifically, in the example, as shown in the above embodiment, the lower inclined portion forming step, the temporary forming section forming step, and the reforming step are performed on the cylindrical body having the shape shown in FIG. In the comparative example, an example in which a reduced-diameter portion forming step of forming a reduced-diameter portion having a shape indicated by a chain line in FIG. 8 (a forming step in a range indicated by a range A in FIG. 8) is performed. Show. Among these, the inclination angle θ1 of the lower inclined portion with respect to the can axis in the embodiment is 32 °, and the inclined angle θ2 of the upper inclined portion with respect to the can axis is set at 7 °. On the other hand, the inclination angle θ3 of the reduced diameter portion with respect to the can axis in the comparative example is set to 15 °. That is, the reduced diameter portion in the comparative example is formed by one inclined portion. In addition, the width of the cylindrical body having the shape shown in FIG. 2B in the example and the comparative example is 57.6 mm, and the total amount of contraction is 30.1 mm, which is the same amount of contraction. . Further, the outer diameter of the mouth formed after the formation of the reduced diameter portion in the example and the comparative example is set to 33 mm.

  As shown in Table 1, in the reduced diameter portion forming process (lower inclined portion forming process, temporary forming portion forming process, and reforming process) in the example, the drawing process is performed 23 times, so that the first connection portion 12 and the lower portion are formed. The side inclined portion 13, the second connection portion 14, and the upper inclined portion 15 were formed. On the other hand, in the reduced diameter portion forming step in the comparative example, the reduced diameter portion H1 could be formed by performing the drawing process 36 times. From these facts, it was possible to greatly reduce the number of times of diameter reduction by performing the diameter reduction portion forming step of the present invention on the cylindrical body.

DESCRIPTION OF SYMBOLS 1 Bottle can 10 Body 10a Open end 11 Cylindrical part 12 First connecting part 13 Lower inclined part 14 Second connecting part 15 Upper inclined part 15a Temporary forming part 16 Mouth part 16a Cylindrical part for mouth part 20 Bottom part 21 Dome part 22 Heel part 23 Ground contact part 40 Cup 41 Cylindrical body 42 Intermediate molding (cylindrical body)
70 Die reduction die 150 Small cylindrical part 161 Large diameter part 162 Screw part 163 Curl part 501 Bottle can manufacturing equipment 511 Work holding part 512 Molding tool 513 Tool holding part 514 Drive part 515 Support shaft 516 Disk 517 Holding device 518 Supply part 519 Supply side starwheel 601 Discharge side starwheel 611 Discharge part 612 Support shaft 613 Disk H1 Reduced diameter part

Claims (2)

A cylindrical portion, and a diameter is reduced from an upper end portion of the cylindrical portion toward the upper side in the can axis direction, and a longitudinal section passing through the can axis is a linear lower inclined portion, and a can axis direction of the lower inclined portion. An upper inclined portion, which is provided on the upper side, is reduced in diameter toward the upper side in the can axial direction at an angle smaller than the angle of the lower inclined portion with respect to the can axis, and has a straight vertical section passing through the can axis, and the upper inclined portion. A mouth portion provided on the upper side in the can axial direction,
The radius of curvature of the outer surface of the first connecting portion connecting the cylindrical portion and the lower inclined portion is 9 mm or more and 20 mm or less, and the angle of the lower inclined portion with respect to the can axis is 20 ° or more and 60 ° or less, The radius of curvature of the outer surface of the second connecting portion connecting the lower inclined portion and the upper inclined portion is 3 mm or more and 15 mm or less, and the angle of the upper inclined portion with respect to the can axis is 1 ° or more and less than 20 °, The length in the can axis direction from the connecting portion between the first connecting portion and the cylindrical portion to the connecting portion between the second connecting portion and the upper inclined portion is a, from the lower end of the upper inclined portion to the mouth portion. Assuming that the length in the can axis direction up to the lower end of b is b, 2.0 <b / a <4.0, and the outer diameter of the cylindrical portion is c, and the outer diameter of the mouth is d. A bottle can characterized by 0.4 <d / c <0.7. It is a manufacturing method of the bottle can of Claim 1, Comprising:
Forming a cylindrical body having a bottomed cylindrical shape, and forming a reduced diameter portion forming the lower inclined portion and the upper inclined portion by reducing the diameter of the cylindrical body toward the upper side in the axial direction of the can. Process,
The diameter-reduced portion molding step is performed by pressing a plurality of diameter-reducing dies having different diameters of the molding surface against the cylindrical body and relatively moving in the can axis direction, so that the angle with respect to the can axis is 20 ° or more and 60 ° or less. Yes, the lower inclined portion whose longitudinal section passing through the can axis is linear is formed, and the radius of curvature of the outer surface of the first connecting portion that connects the cylindrical portion and the lower inclined portion is 9 mm or more and 20 mm or less. Together with a lower inclined portion forming step of molding a small cylindrical portion extending linearly upward in the can axial direction from the upper end of the lower inclined portion via the second connection portion;
By pressing a plurality of diameter reducing dies having different diameters of the molding surface against the outer surface of the small cylindrical portion formed by the lower inclined portion forming step and relatively moving in the can axis direction, a longitudinal section passing through the can axis A temporary forming part forming step of forming a step-like temporary forming part whose diameter is reduced as going upward.
By pressing a plurality of diameter reducing dies having different diameters of the forming surface against the outer surface of the temporary forming portion formed in the temporary forming portion forming step and relatively moving the same, the temporary forming portion is smoothed and the upward inclined Forming a portion, and a reforming step of setting a radius of curvature of an outer surface of a second connecting portion connecting the lower inclined portion and the upper inclined portion to 3 mm or more and 15 mm or less, Production method.

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