JP2021035696A - Method for production of bottle can - Google Patents

Method for production of bottle can Download PDF

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JP2021035696A
JP2021035696A JP2020184600A JP2020184600A JP2021035696A JP 2021035696 A JP2021035696 A JP 2021035696A JP 2020184600 A JP2020184600 A JP 2020184600A JP 2020184600 A JP2020184600 A JP 2020184600A JP 2021035696 A JP2021035696 A JP 2021035696A
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diameter
end side
neck
cylindrical
bottle
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JP7112648B2 (en
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孝太朗 島田
Koutarou Shimada
孝太朗 島田
一 実末
Hajime Jitsusue
一 実末
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Altemira Can Co Ltd
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Universal Can Corp
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Abstract

To produce a thin-wall bottle can while preventing occurrence of buckling.SOLUTION: A method for production of a thin-wall bottle can comprises: a DI press process of molding a bottomed cylindrical body in which a bottom and a cylindrical part are formed by applying re-squeezing, an iron process and a bottom molding process to a cup-shaped material molded by a squeezing process from an iron plate; a bottle neck molding process of molding a shoulder part 6 and a neck part 7 diameter-reduced as heading for an upper end side from the shoulder part 6; and a cap fitting part-molding process of molding the cap fitting part to the upper end part of the neck part 7. In the bottle neck molding process, the neck part 7 is molded by stepwise in several times, diameter-reducing a portion excluding the portion connected to the shoulder part 6 in a cylindrical part formed at the upper end side of the shoulder part 6 from d0 into d2 in diameter. One time amount of diameter reduction is made to be in a rage of 0.5 to 1.5 mm.SELECTED DRAWING: Figure 6

Description

本発明は、ボトル缶の製造方法に関するものである。 The present invention relates to a method for producing a bottle can.

このようなボトル缶の製造方法として、例えば特許文献1には、アルミニウム合金等の金属材料から絞り加工、絞りしごき加工またはインパクト成形によって造られ、かつ缶本体がキャップ取付部としてのねじ部を有する口部、テーパー状の肩部、胴部および底部から構成され、キャップを螺合して高い密封性を保持できるねじ付金属缶において、口部のねじ部下端から、半径方向に拡大するテーパー状の肩部上端周囲に、内側に滑らかに湾曲する凹部を形成するとともに、この凹部の下方の連続して外側に滑らかに湾曲する凸部を形成することが記載されている。さらに、この特許文献1では、凹部から連続する滑らかな凸部の湾曲の程度として、垂直方向すなわち缶軸に対して35°〜60°の傾斜角、具体的には45°の傾斜角とするのが好ましいと記載されている。 As a method for manufacturing such a bottle can, for example, Patent Document 1 states that it is manufactured from a metal material such as an aluminum alloy by drawing, squeezing, or impact forming, and the can body has a threaded portion as a cap mounting portion. In a threaded metal can that consists of a mouth, tapered shoulder, body and bottom, and can maintain high sealing performance by screwing a cap, a tapered shape that expands in the radial direction from the lower end of the threaded part of the mouth. It is described that a concave portion that curves smoothly inward is formed around the upper end of the shoulder portion of the shoulder portion, and a convex portion that continuously curves outward smoothly below the concave portion is formed. Further, in Patent Document 1, the degree of curvature of the smooth convex portion continuous from the concave portion is set to an inclination angle of 35 ° to 60 ° with respect to the vertical direction, that is, a can axis, specifically, an inclination angle of 45 °. Is stated to be preferable.

また、例えば特許文献2には、有底筒状に形成されたアルミニウム合金等の金属製の缶体(有底円筒体)の開口部を縮径してなる口金部の上部外周にねじ部が設けられるとともに、このねじ部よりも下方にキャップ本体下部を巻き締めるための膨出部が形成されたボトル缶の製造方法であって、上記開口部を縮径して口金部を形成した後、その口金部の開口端から所定距離分だけ再び拡径して拡径部を形成し、上記ねじ部は、拡径部が形成された後、ねじを形成する部分を縮径して、その縮径された部分にねじ切り加工することによって形成され、上記膨出部は、ねじ部を形成する際に縮径されずに残った拡径部分によって形成されるボトル缶の製造方法が記載されている。この場合に、上記開口部を縮径した口金部における上記膨出部の下方には、肩部から上端側に延びる首部が形成される。 Further, for example, in Patent Document 2, a screw portion is provided on the upper outer periphery of a base portion formed by reducing the diameter of an opening of a metal can body (bottomed cylindrical body) such as an aluminum alloy formed in a bottomed tubular shape. This is a method for manufacturing a bottle can in which a bulging portion for winding the lower part of the cap body is formed below the screw portion as well as being provided. The diameter is expanded again by a predetermined distance from the opening end of the base portion to form a diameter-expanded portion, and after the diameter-expanded portion is formed, the diameter of the portion forming the screw is reduced and the diameter of the screw portion is reduced. A method for manufacturing a bottle can, which is formed by threading a diametered portion and is formed by an enlarged diameter portion remaining without being reduced in diameter when forming the threaded portion, is described. .. In this case, a neck portion extending from the shoulder portion to the upper end side is formed below the bulging portion in the mouthpiece portion having a reduced diameter of the opening portion.

ここで、上述のような肩部の成形は、内径が徐々に小さくなる円筒状の複数の金型を、内径が大きいものから順に有底円筒体の円筒部の上端側部分に圧入して順次塑性変形させることにより、この円筒部の上端側部分のうちの下端側部分を上端側に向けて段階的に内周側に向かうように傾斜させるとともに、この傾斜した下端側部分よりも内周側を内径が小さくなる円筒状に徐々に縮径させることによって行われる。 Here, in the molding of the shoulder portion as described above, a plurality of cylindrical dies whose inner diameters gradually decrease are press-fitted into the upper end side portion of the cylindrical portion of the bottomed cylinder in order from the one having the largest inner diameter. By plastically deforming, the lower end side portion of the upper end side portion of the cylindrical portion is inclined toward the upper end side in a stepwise manner toward the inner peripheral side, and the inner peripheral side of the inclined lower end side portion. This is done by gradually reducing the diameter of the cylinder into a cylindrical shape with a smaller inner diameter.

さらに、特許文献2に記載された膨出部の成形は、こうして傾斜させられた肩部の内周側に縮径した円筒状の首部が成形された後に、この首部の内径よりも僅かに大きな外径の下端外周部を有する拡径工具を上端側から首部に挿入して拡径させ、次いでこの拡径した部分の上端側にねじ切り加工することにより、上述のようにねじ切り加工によって縮径されずに残された部分として成形される。 Further, the molding of the bulging portion described in Patent Document 2 is slightly larger than the inner diameter of the bulging portion after the cylindrical neck portion having a reduced diameter is formed on the inner peripheral side of the shoulder portion inclined in this way. A diameter-expanding tool having an outer peripheral portion at the lower end of the outer diameter is inserted into the neck from the upper end side to expand the diameter, and then thread cutting is performed on the upper end side of the expanded portion, so that the diameter is reduced by thread cutting as described above. It is molded as the part left behind.

特開2001−213416号公報Japanese Unexamined Patent Publication No. 2001-21316 特許第4908544号公報Japanese Patent No. 4908544

ところで、近年では、このようなボトル缶を形成する金属材料の省資源化や材料製造の際の省エネルギー化のために缶本体のさらなる薄肉化が強く求められており、例えばアルミニウム合金製のボトル缶の場合には、板厚が0.230mm〜0.300mm程度のアルミニウム合金よりなる金属板から絞り加工により成形されたカップ状素材に再絞りおよびしごき加工を施して上述のような有底円筒体を成形し、さらに肩部や首部、膨出部を成形するとともにねじ切り加工を行ってボトル缶の缶本体を製造するようなことも要求されている。 By the way, in recent years, there has been a strong demand for further thinning of the can body in order to save resources in the metal material forming such a bottle can and save energy in material production. For example, a bottle can made of an aluminum alloy. In the case of, the cup-shaped material formed by drawing from a metal plate made of an aluminum alloy having a plate thickness of about 0.230 mm to 0.300 mm is re-squeezed and ironed to form a bottomed cylindrical body as described above. It is also required to form a can body of a bottle can by forming a shoulder portion, a neck portion, and a bulging portion as well as threading.

しかしながら、このように有底円筒体の薄肉化を図ったボトル缶では有底円筒体の強度は低下することになり、特許文献1に記載されているように凸部の缶軸に対する傾斜角が大きくて首部を成形する際の荷重が大きくなったり、あるいは特許文献2に記載された膨出部を成形する際の荷重が大きくなったりすると、首部の成形の際に有底円筒体に座屈が生じるおそれがある。特に、有底円筒体を成形する際には、肩部や首部、膨出部やキャップ取付部を形成する有底円筒体の円筒部における上端側部分よりも、この円筒部の下端側部分の肉厚を薄くすることがあり、そのような有底円筒体では薄肉とされた胴部の下端側部分での座屈が一層顕著なものとなる。また、膨出部を成形する際の荷重が大きいと膨出部に割れを生じるおそれがある。 However, in a bottle can in which the bottomed cylinder is thinned in this way, the strength of the bottomed cylinder is reduced, and as described in Patent Document 1, the inclination angle of the convex portion with respect to the can shaft is increased. If the load is large and the load for molding the neck is large, or if the load for molding the bulge described in Patent Document 2 is large, the neck is buckled on the bottomed cylinder during molding. May occur. In particular, when molding a bottomed cylinder, the lower end side portion of the bottomed cylinder portion is more than the upper end side portion of the bottomed cylinder portion forming the shoulder portion, the neck portion, the bulging portion and the cap mounting portion. The wall thickness may be reduced, and in such a bottomed cylinder, buckling at the lower end side portion of the thinned body portion becomes more remarkable. Further, if the load when forming the bulging portion is large, the bulging portion may be cracked.

本発明は、このような背景の下になされたもので、ボトル缶の缶本体に成形される金属板や有底円筒体の薄肉化を図っても、首部の成形の際に有底円筒体に座屈が生じるのを防ぐことが可能なボトル缶の製造方法を提供することを目的としている。 The present invention has been made under such a background, and even if the metal plate and the bottomed cylinder to be molded on the can body of the bottle can are thinned, the bottomed cylinder is formed when the neck is molded. It is an object of the present invention to provide a method for producing a bottle can, which can prevent buckling.

上記課題を解決して、このような目的を達成するために、本発明は、缶本体の底部と一体に成形される外周部に、上記底部から上記缶本体の上端開口部に向けて順に缶軸を中心とした円筒状の胴部と、上端側に向かうに従い縮径する肩部と、この肩部からさらに上端側に向かって延びる首部と、キャップ取付部とが形成されたボトル缶の製造方法であって、金属板から絞り加工により成形されたカップ状素材に再絞りおよびしごき加工と底部成形加工を施して、上記底部と、上記胴部と同外径の円筒部が形成された有底円筒体を成形するDIプレス工程と、この有底円筒体の上記円筒部の上端側部分を縮径させることにより、上記肩部と、この肩部から上端側に向かうに従いさらに縮径する上記首部とを成形するボトルネック成形工程と、上記首部の上端部に上記キャップ取付部を成形するキャップ取付部成形工程とを備え、上記ボトルネック成形工程においては、上記肩部の上端側に形成された円筒状部のうち上記肩部との接続部分を除いた部分を直径d0から直径d2まで複数回に分けて段階的に縮径することによって上記首部を成形する構成とされており、1回の縮径量が0.5mm〜1.5mmの範囲内とされていることを特徴とする。 In order to solve the above problems and achieve such an object, the present invention presents a can in order from the bottom portion toward the upper end opening of the can body on an outer peripheral portion formed integrally with the bottom portion of the can body. Manufacture of bottle cans in which a cylindrical body centered on a shaft, a shoulder portion whose diameter decreases toward the upper end side, a neck portion extending further toward the upper end side from this shoulder portion, and a cap attachment portion are formed. In this method, a cup-shaped material formed by drawing from a metal plate is re-squeezed, ironed, and bottom-formed to form a bottom portion and a cylindrical portion having the same outer diameter as the body portion. By reducing the diameter of the DI press step of forming the bottom cylindrical body and the upper end side portion of the cylindrical portion of the bottomed cylindrical body, the diameter of the shoulder portion and the diameter is further reduced from the shoulder portion toward the upper end side. A bottleneck molding step of molding the neck portion and a cap mounting portion molding step of molding the cap mounting portion on the upper end portion of the neck portion are provided, and in the bottleneck molding step, the cap mounting portion is formed on the upper end side of the shoulder portion. The neck portion is formed by gradually reducing the diameter of the cylindrical portion excluding the connecting portion with the shoulder portion in a plurality of times from the diameter d0 to the diameter d2. The diameter reduction amount of is in the range of 0.5 mm to 1.5 mm.

このようなボトル缶の製造方法においては、首部における縮径が複数回に分けて段階的に行われるので、個々の段階における縮径量を少なくすることができ、缶軸方向の荷重を小さくすることができる。このため、たとえカップ状素材に成形される金属板の板厚が0.230mm〜0.300mmと薄く、またこのカップ状素材から成形された有底円筒体における円筒部の上端側部分の厚さも0.180mm〜0.225mmと薄くて、さらに円筒部の下端側部分の厚さはこれよりも薄い場合であっても、首部の成形の際の荷重によって有底円筒体に座屈が生じたり、膨出部の成形の際の荷重によって割れが生じたりするのを防ぐことができる。従って、上記構成のボトル缶の製造方法によれば、このような座屈や割れによるボトル缶の製造歩留まりや製造効率等の低下を招くことなく、ボトル缶の缶本体の薄肉化を図ることができ、さらなる省資源化や省エネルギー化を促すことが可能となる。 In such a method for manufacturing a bottle can, the diameter reduction at the neck is performed stepwise in a plurality of times, so that the amount of diameter reduction at each step can be reduced and the load in the can axial direction is reduced. be able to. Therefore, even if the thickness of the metal plate formed into the cup-shaped material is as thin as 0.230 mm to 0.300 mm, the thickness of the upper end side portion of the cylindrical portion in the bottomed cylinder formed from this cup-shaped material is also Even if it is as thin as 0.180 mm to 0.225 mm and the thickness of the lower end side of the cylinder is thinner than this, the bottomed cylinder may buckle due to the load during molding of the neck. , It is possible to prevent cracks from occurring due to the load during molding of the bulging portion. Therefore, according to the method for manufacturing a bottle can having the above configuration, it is possible to reduce the thickness of the can body of the bottle can without causing a decrease in the manufacturing yield and manufacturing efficiency of the bottle can due to such buckling and cracking. It is possible to promote further resource saving and energy saving.

なお、このようなボトル缶の缶本体に有底円筒体を経て成形される上記金属板は、JIS H 4000におけるA3004またはA3104のアルミニウム合金であって、205℃×20分ベーキング後の0.2%耐力が235N/mm〜265N/mmの範囲であることが望ましい。このベーキング後の耐力が235N/mmを下回ると、上述のような傾斜角や外径拡縮径量としても首部や膨出部の成形の際に有底円筒体の座屈や割れが生じるおそれがあり、また逆にベーキング後の耐力が265N/mmを上回っても、成形に必要な荷重が大きくなって荷重制御が困難となるおそれがある。 The metal plate formed on the main body of such a bottle can via a bottomed cylinder is an aluminum alloy of A3004 or A3104 in JIS H 4000, and is 0.2 at 205 ° C. × 20 minutes after baking. It is desirable that the% proof stress is in the range of 235 N / mm 2 to 265 N / mm 2. If the proof stress after baking is less than 235 N / mm 2 , the bottomed cylindrical body may buckle or crack during molding of the neck or bulge even if the inclination angle and the outer diameter expansion / contraction amount are as described above. On the contrary, even if the proof stress after baking exceeds 265 N / mm 2 , the load required for molding becomes large and the load control may become difficult.

以上説明したように、本発明によれば、首部を成形する際の有底円筒体の座屈を防止することができ、このような座屈によるボトル缶の製造歩留まりや製造効率等の低下を防ぎつつ、ボトル缶の缶本体のさらなる薄肉化を図って、一層の省資源化や省エネルギー化を促進することが可能となる。 As described above, according to the present invention, it is possible to prevent buckling of the bottomed cylindrical body when molding the neck portion, and such buckling reduces the manufacturing yield and manufacturing efficiency of bottle cans. While preventing this, it is possible to further reduce the thickness of the can body of the bottle can to further promote resource saving and energy saving.

本発明の一実施形態により製造されるボトル缶の一部破断側面図である。It is a partially broken side view of the bottle can manufactured by one Embodiment of this invention. 本発明の一実施形態を示すフローチャートである。It is a flowchart which shows one Embodiment of this invention. 本発明の一実施形態におけるボトルネック成形工程において(a)首部が成形される前の有底円筒体を示す断面図、(b)首部を成形する金型(第1の金型)を示す断面図である。In the bottleneck molding step according to the embodiment of the present invention, (a) a cross-sectional view showing a bottomed cylindrical body before the neck portion is molded, and (b) a cross section showing a mold (first mold) for molding the neck portion. It is a figure. 本発明の一実施形態におけるボトルネック成形工程において(a)第1の段階の縮径を行う第1の金型の断面図、(b)図(a)に示す第1の金型の首部成形部周辺を示す拡大断面図である。In the bottleneck molding step according to the embodiment of the present invention, (a) a cross-sectional view of a first mold for reducing the diameter in the first step, and (b) molding the neck of the first mold shown in FIG. It is an enlarged cross-sectional view which shows the periphery of a part. 本発明の一実施形態におけるボトルネック成形工程において(a)第2の段階の縮径を行う第2の金型の断面図、(b)図(a)に示す第2の金型の首部成形部周辺を示す拡大断面図である。In the bottleneck molding step according to the embodiment of the present invention, (a) a cross-sectional view of a second mold for reducing the diameter in the second step, and (b) molding the neck of the second mold shown in FIG. It is an enlarged cross-sectional view which shows the periphery of a part. 本発明の一実施形態のボトルネック成形工程により首部が成形された有底円筒体を示す断面図である。It is sectional drawing which shows the bottomed cylinder whose neck part was molded by the bottleneck molding process of one Embodiment of this invention. 本発明の一実施形態におけるキャップ取付部成形工程において(a)膨出部が成形される前の有底円筒体を示す断面図、(b)膨出部を成形する拡径工具(第1の拡径工具)を示す断面図である。In the cap mounting portion forming step according to the embodiment of the present invention, (a) a cross-sectional view showing a bottomed cylinder before the bulging portion is formed, and (b) a diameter-expanding tool for forming the bulging portion (first). It is sectional drawing which shows the diameter expansion tool). 本発明の一実施形態におけるキャップ取付部成形工程において(a)第1の段階の拡径を行う第1の拡径工具の断面図、(b)図(a)に示す第1の拡径工具の拡径部周辺を示す拡大断面図である。In the cap mounting portion forming step according to the embodiment of the present invention, (a) a cross-sectional view of a first diameter-expanding tool for expanding the diameter in the first step, and (b) a first diameter-expanding tool shown in FIG. It is an enlarged cross-sectional view which shows the periphery of the enlarged diameter part of. 本発明の一実施形態におけるキャップ取付部成形工程において(a)第2の段階の拡径を行う第2の拡径工具の断面図、(b)図(a)に示す第2の拡径工具の拡径部周辺を示す拡大断面図である。In the cap mounting portion forming step according to the embodiment of the present invention, (a) a cross-sectional view of a second diameter-expanding tool that expands the diameter in the second stage, and (b) a second diameter-expanding tool shown in FIG. It is an enlarged cross-sectional view which shows the periphery of the enlarged diameter part of. 本発明の一実施形態のキャップ取付部成形工程により膨出部が成形された有底円筒体を示す断面図である。It is sectional drawing which shows the bottomed cylindrical body which the bulging part was molded by the cap attachment part molding process of one Embodiment of this invention.

図1は、本発明の一実施形態により製造されるボトル缶の缶本体1を示すものであり、図2ないし図10は、このような缶本体1を製造するための本発明の一実施形態を示すものである。本実施形態によって製造されるボトル缶は、その缶本体1が図1に示すように、底部2と、この底部2と一体に形成されて底部2の外周縁から上端側(図1において上側)に延びる外周部3とを備えており、この上端側に向けて縮径する缶軸Cを中心とした概略多段の有底円筒状をなしている。 FIG. 1 shows a can body 1 of a bottle can manufactured according to an embodiment of the present invention, and FIGS. 2 to 10 show an embodiment of the present invention for manufacturing such a can body 1. Is shown. As shown in FIG. 1, the bottle can manufactured by the present embodiment is formed integrally with the bottom portion 2 and the bottom portion 2, and the can body 1 is formed integrally with the bottom portion 2 from the outer peripheral edge to the upper end side (upper side in FIG. 1). It is provided with an outer peripheral portion 3 extending to the upper end side, and has a substantially multi-stage bottomed cylindrical shape centered on a can shaft C whose diameter is reduced toward the upper end side.

底部2には、缶軸C方向の内側(缶本体1の上端側)に凹む断面略円弧状のドーム部2aが中央に形成されるとともに、このドーム部2aの外周には缶軸C方向の外側(缶本体1の下端側)に突出する上記環状凸部2bが缶軸C回りの周方向に連続して形成されている。また、外周部3には底部2から缶本体1の上端側の開口部4に向けて順に、缶軸Cを中心とした円筒状の胴部5と、上端側に向かうに従い一定の傾斜で漸次縮径する円錐台面状の肩部6と、この肩部6からさらに上端側に向かって延びる筒状の首部7と、下端側に上記膨出部8を備えたやはり筒状で、本実施形態ではねじ切り加工が施されたキャップ取付部9とが形成されている。 A dome portion 2a having a substantially arcuate cross section recessed inward in the can axis C direction (upper end side of the can body 1) is formed in the center of the bottom portion 2, and the outer periphery of the dome portion 2a is formed in the can axis C direction. The annular convex portion 2b projecting to the outside (lower end side of the can body 1) is continuously formed in the circumferential direction around the can axis C. Further, the outer peripheral portion 3 has a cylindrical body portion 5 centered on the can shaft C in order from the bottom portion 2 toward the opening 4 on the upper end side of the can body 1, and gradually has a constant inclination toward the upper end side. This embodiment also has a conical pedestal-shaped shoulder portion 6 with a reduced diameter, a tubular neck portion 7 extending from the shoulder portion 6 toward the upper end side, and a bulging portion 8 on the lower end side. Is formed with a cap mounting portion 9 that has been threaded.

このようなボトル缶を製造する本発明のボトル缶の製造方法の一実施形態においては、図2のフローチャートに示すように、まずカッピングプレス機によるカッピングプレス工程においてアルミニウム合金等の金属板を円板状に打ち抜いて絞り加工を施すことにより深さの浅いカップ状素材を製造し、このカップ状素材にDIプレス機によるDIプレス工程において再絞りおよびしごき加工を施して缶軸C方向に延伸することにより、底部2に上記ドーム部2aと環状凸部2bが形成された有底円筒体(DI缶)を成形する。 In one embodiment of the method for manufacturing a bottle can of the present invention for manufacturing such a bottle can, as shown in the flowchart of FIG. 2, first, a metal plate such as an aluminum alloy is formed into a disk in a cupping press step by a cupping press machine. A cup-shaped material with a shallow depth is manufactured by punching it into a shape and drawing, and this cup-shaped material is re-squeezed and ironed in the DI pressing process using a DI press machine to be stretched in the can axis C direction. A bottomed cylindrical body (DI can) in which the dome portion 2a and the annular convex portion 2b are formed on the bottom portion 2 is formed.

ここで、カッピングプレス工程においてカップ状素材に成形される金属板は、本実施形態ではJIS H 4000におけるA3004またはA3104のアルミニウム合金であって、205℃×20分ベーキング後の0.2%耐力が235N/mm〜265N/mmの範囲のものが用いられる。また、このカップ状素材から成形される有底円筒体には、外周部に上記缶軸Cを中心とした円筒部が形成され、この円筒部の外径は缶本体1の胴部5の外径と略等しい一定外径である。ただし、この円筒部は、その上端側部分の厚さが0.180mm〜0.225mmの範囲である一方、下端側部分の厚さはこの上端側部分よりも極僅かに薄い。 Here, the metal plate formed into the cup-shaped material in the cupping press step is an aluminum alloy of A3004 or A3104 in JIS H 4000 in the present embodiment, and has a 0.2% proof stress after baking at 205 ° C. for 20 minutes. Those in the range of 235 N / mm 2 to 265 N / mm 2 are used. Further, in the bottomed cylindrical body formed from this cup-shaped material, a cylindrical portion centered on the can shaft C is formed on the outer peripheral portion, and the outer diameter of this cylindrical portion is outside the body portion 5 of the can body 1. It has a constant outer diameter that is approximately equal to the diameter. However, the thickness of the upper end side portion of this cylindrical portion is in the range of 0.180 mm to 0.225 mm, while the thickness of the lower end side portion is extremely slightly thinner than the upper end side portion.

このように成形された有底円筒体は、第1の洗浄工程において洗浄、乾燥され、次いで塗装工程において内外面に塗装が施されて焼き付けられる。そして、塗装が施された有底円筒体は、ボトルネッカーによるボトルネック成形工程において円筒部の上記上端側部分の下端側が金型によって縮径されて上記肩部6と首部7が成形され、次いでキャップ取付部成形工程において首部7の上端側が拡径工具によって拡径されて上記膨出部8が形成されるとともに、この膨出部8よりもさらに上端側に上記ねじ切り加工等が施されて上記キャップ取付部9が形成され、図1に示したようなボトル缶の缶本体1に成形される。 The bottomed cylinder thus formed is washed and dried in the first washing step, and then the inner and outer surfaces are painted and baked in the painting step. Then, in the bottomed cylindrical body that has been painted, the lower end side of the upper end side portion of the cylindrical portion is reduced in diameter by a mold in the bottleneck molding step by the bottle necker, and the shoulder portion 6 and the neck portion 7 are molded, and then the shoulder portion 6 and the neck portion 7 are formed. In the cap mounting portion forming step, the upper end side of the neck portion 7 is enlarged by a diameter-expanding tool to form the bulging portion 8, and the upper end side of the bulging portion 8 is further threaded or the like. The cap mounting portion 9 is formed and molded into the can body 1 of the bottle can as shown in FIG.

こうして成形された缶本体1は、第2の洗浄工程によって洗浄、乾燥された後に、検査工程においてピンホールの有無や外面の異物付着、傷、汚れ、印刷不良等が検査されて飲料工場等に搬送され、飲料等の内容物が充填された後にキャップ取付部9に図示されないキャップが取り付けられて封止され、出荷される。なお、上記各工程の間や各工程中には、有底円筒体の上端縁を切断するトリミングや、必要に応じて底部の環状凸部2bの断面形状を再成形するボトムリフォームが行われる。 The can body 1 thus molded is washed and dried by the second washing step, and then inspected for the presence or absence of pinholes, foreign matter adhesion on the outer surface, scratches, stains, printing defects, etc. After being transported and filled with contents such as beverages, a cap (not shown) is attached to the cap attachment portion 9, the cap is sealed, and the product is shipped. During or during each of the above steps, trimming is performed to cut the upper end edge of the bottomed cylindrical body, and bottom reform is performed to reshape the cross-sectional shape of the annular convex portion 2b at the bottom, if necessary.

ここで、ボトルネッカーによるボトルネック成形工程のうち、上記肩部6の成形は、内径が徐々に小さくなる円筒状の複数の上記金型を、内径が大きいものから順に有底円筒体の円筒部の上端側部分に圧入して塑性変形させることにより、この円筒部の上端側部分のうちの下端側部分を上端側に向けて段階的に内周側に向かうように傾斜させるとともに、この傾斜した下端側部分よりも内周側を内径が小さくなる円筒状に徐々に縮径させることによって行われる。 Here, in the bottleneck molding step by the bottle necker, in the molding of the shoulder portion 6, a plurality of cylindrical molds having an inner diameter gradually decreasing are formed, and the cylindrical portion of the bottomed cylindrical body is formed in order from the one having the largest inner diameter. By press-fitting into the upper end side portion of the cylinder and plastically deforming it, the lower end side portion of the upper end side portion of the cylindrical portion is inclined toward the upper end side in a stepwise manner toward the inner peripheral side, and this inclination is achieved. This is done by gradually reducing the inner peripheral side of the lower end side into a cylindrical shape with a smaller inner diameter.

図3(a)に示すのは、このように上記ボトルネック成形工程において肩部6の成形が終了した有底円筒体10Aであり、肩部6の内周部上端側には缶軸Cを中心として縮径させられた円筒状部11Aが形成されている。そして、図3(b)および図4と図5とに示すのは、この有底円筒体10Aの円筒状部11Aに首部7を成形する第1、第2の金型21A、21Bであり、本実施形態のボトルネック成形工程においては、これら第1、第2の金型21A、21Bをこの順に有底円筒体10Aの肩部6から上端側の上記円筒状部11Aに挿入することにより、この円筒状部11Aを複数回(2回)に分けて段階的に縮径して首部7を成形する。 FIG. 3A shows a bottomed cylindrical body 10A in which the molding of the shoulder portion 6 has been completed in the bottleneck molding step, and a can shaft C is provided on the upper end side of the inner peripheral portion of the shoulder portion 6. A cylindrical portion 11A whose diameter is reduced as the center is formed. 3 (b) and 4 and 5 show the first and second dies 21A and 21B for forming the neck portion 7 into the cylindrical portion 11A of the bottomed cylindrical body 10A. In the bottleneck molding step of the present embodiment, the first and second dies 21A and 21B are inserted in this order from the shoulder portion 6 of the bottomed cylindrical body 10A into the cylindrical portion 11A on the upper end side. The cylindrical portion 11A is divided into a plurality of times (twice) and the diameter is gradually reduced to form the neck portion 7.

これら第1、第2の金型21A、21Bは缶軸Cと同軸となるように配置される略円筒状をなしていて、その内周部には下端側から上端側に向けて順にそれぞれ、缶軸Cを中心とする大径円筒部22A、22Bと、内周側に向かうに従い上端側に向かうように傾斜する凹円錐台面状部23A、23Bと、首部成形部24A、24Bと、小径円筒部25A、25Bとが形成されている。 These first and second molds 21A and 21B have a substantially cylindrical shape arranged so as to be coaxial with the can shaft C, and the inner peripheral portions thereof are in order from the lower end side to the upper end side, respectively. Large-diameter cylindrical portions 22A and 22B centered on the can shaft C, concave conical pedestal portions 23A and 23B that incline toward the upper end side toward the inner peripheral side, neck forming portions 24A and 24B, and a small-diameter cylinder. Parts 25A and 25B are formed.

大径円筒部22A、22Bは、有底円筒体10Aの円筒部(缶本体1の胴部5)の外周面が嵌合可能な内径を有しており、また凹円錐台面状部23A、23Bは有底円筒体10Aの肩部6よりも缶軸Cに対して大きな傾斜で内周側に向かうに従い上端側に向かうように傾斜している。これら大径円筒部22A、22Bと凹円錐台面状部23A、23Bの形状、寸法は第1、第2の金型21A、21Bで同じである。 The large-diameter cylindrical portions 22A and 22B have an inner diameter that allows the outer peripheral surface of the cylindrical portion (body portion 5 of the can body 1) of the bottomed cylindrical body 10A to be fitted, and the concave conical base surface portions 23A and 23B. Is more inclined with respect to the can shaft C than the shoulder portion 6 of the bottomed cylindrical body 10A, and is inclined toward the upper end side toward the inner peripheral side. The shapes and dimensions of the large-diameter cylindrical portions 22A and 22B and the concave conical base surface portions 23A and 23B are the same for the first and second molds 21A and 21B.

さらに、首部成形部24A、24Bは下端側から上端側に向けて順に、それぞれ缶軸Cに沿った断面において図4(b)および図5(b)に拡大して示すように、凹円錐台面状部23A、23Bの上端に接する凸円弧等をなす第1凸曲部24aと、この第1凸曲部24aの上端に接して缶軸Cに略平行に上端側に延びる直線状をなす円環部24bと、この円環部24bの上端に接して第1凸曲部24aよりも半径の大きな凹円弧等をなす凹曲部24cと、この凹曲部24cの上端に接して上端側に向かうに従い内周側に向かうように缶軸Cに対して傾斜した直線状をなす傾斜部24dと、この傾斜部24dの上端と小径円筒部25A、25Bの下端とに接する凸円弧等をなす第2凸曲部24eとを備えている。 Further, the neck forming portions 24A and 24B have a concave conical base surface as shown enlarged in FIGS. 4 (b) and 5 (b) in the cross section along the can shaft C in order from the lower end side to the upper end side, respectively. A first convex curved portion 24a forming a convex arc or the like in contact with the upper ends of the shaped portions 23A and 23B, and a linear circle extending toward the upper end side substantially parallel to the can shaft C in contact with the upper end of the first convex curved portion 24a. The ring portion 24b, the concave curved portion 24c which is in contact with the upper end of the annular portion 24b and forms a concave arc or the like having a larger radius than the first convex curved portion 24a, and the concave portion 24c which is in contact with the upper end of the concave curved portion 24c and is on the upper end side. A linear inclined portion 24d that is inclined with respect to the can shaft C so as to be directed toward the inner peripheral side, and a convex arc or the like that is in contact with the upper end of the inclined portion 24d and the lower ends of the small-diameter cylindrical portions 25A and 25B. It is provided with a two-convex curved portion 24e.

ここで、円環部24bの内径(直径)d0と缶軸C方向の長さは、第1、第2の金型21A、21Bで互いに等しくされており、円環部24bの内径d0は肩部6の成形が終了した有底円筒体10Aの上記円筒状部11Aが嵌合可能な大きさとされている。また、凹曲部24cの断面がなす円弧等の半径および缶軸C方向の長さも、第1、第2の金型21A、21Bで互いに等しい。従って、このような第1、第2の金型21A、21Bを、肩部6の成形終了後の有底円筒体10Aの上端側から図3に白抜き矢線で示すように缶軸Cと同軸に挿入すると、円筒状部11Aは上端側から円環部24bの内周面に摺接しつつ凹曲部24cおよび傾斜部24dに沿って縮径させられる。 Here, the inner diameter (diameter) d0 of the annular portion 24b and the length in the can axis C direction are equal to each other in the first and second molds 21A and 21B, and the inner diameter d0 of the annular portion 24b is the shoulder. The cylindrical portion 11A of the bottomed cylindrical body 10A for which the molding of the portion 6 has been completed is sized to fit. Further, the radius of the arc and the like formed by the cross section of the concave portion 24c and the length in the can axis C direction are also equal to each other in the first and second molds 21A and 21B. Therefore, such first and second dies 21A and 21B are attached to the can shaft C from the upper end side of the bottomed cylindrical body 10A after the molding of the shoulder portion 6 is completed, as shown by the white arrow lines in FIG. When inserted coaxially, the cylindrical portion 11A is reduced in diameter along the concave portion 24c and the inclined portion 24d while sliding in contact with the inner peripheral surface of the annular portion 24b from the upper end side.

そして、これら第1、第2の金型21A、21Bにおいては、首部成形部24A、24Bの傾斜部24dの缶軸Cに対する傾斜角αは互いに等しいのに対して、第1の金型21Aにおける首部成形部24Aの傾斜部24dの缶軸C方向の長さが、第2の金型21Bにおける首部成形部24Bの傾斜部24dの缶軸C方向の長さよりも短くなるように形成されている。 In these first and second dies 21A and 21B, the inclination angles α of the inclined portions 24d of the neck forming portions 24A and 24B with respect to the can shaft C are equal to each other, whereas in the first mold 21A. The length of the inclined portion 24d of the neck forming portion 24A in the can axis C direction is formed to be shorter than the length of the inclined portion 24d of the neck forming portion 24B in the second mold 21B in the can axis C direction. ..

これにより、第1の金型21Aにおける小径円筒部25Aの内径(直径)d1は、有底円筒体10Aの円筒状部11Aの外径よりも小さく、ただし第2の金型21Bにおける小径円筒部25Bの内径(直径)d2よりは大きくされる。なお、第2凸曲部24eの断面がなす円弧等の半径および缶軸C方向の長さは、第1、第2の金型21A、21Bで互いに等しくされている。 As a result, the inner diameter (diameter) d1 of the small-diameter cylindrical portion 25A in the first mold 21A is smaller than the outer diameter of the cylindrical portion 11A of the bottomed cylindrical body 10A, but the small-diameter cylindrical portion in the second mold 21B. It is made larger than the inner diameter (diameter) d2 of 25B. The radius of the arc and the like formed by the cross section of the second convex portion 24e and the length in the can axis C direction are equal to each other in the first and second molds 21A and 21B.

従って、第1の金型21Aにおける凹円錐台面状部23Aの上端位置が肩部6の上端位置と缶軸C方向に一致して第1の金型21Aがストロークエンド(下死点)に達したところで、円筒状部11Aの上端側部分は第1の金型21Aの小径円筒部25Aの内径d1と略等しい外径に絞り込まれて一段縮径されるとともに、こうして縮径した円筒状部11Aの下端側部分から肩部6にかけては、第1の金型21Aの首部成形部24Aの断面形状を略転写したような外周面の断面形状を有する上記首部7が形成される。 Therefore, the upper end position of the concave conical base surface portion 23A in the first mold 21A coincides with the upper end position of the shoulder portion 6 in the can axis C direction, and the first mold 21A reaches the stroke end (bottom dead point). Then, the upper end side portion of the cylindrical portion 11A is narrowed down to an outer diameter substantially equal to the inner diameter d1 of the small diameter cylindrical portion 25A of the first mold 21A and reduced in diameter by one step, and the cylindrical portion 11A thus reduced in diameter. From the lower end side portion to the shoulder portion 6, the neck portion 7 having a cross-sectional shape of an outer peripheral surface as if the cross-sectional shape of the neck portion molding portion 24A of the first mold 21A is substantially transferred is formed.

次いで、第1の金型21Aを有底円筒体10Aから引き抜いて第2の金型21Bを挿入すると、同様に第2の金型21Bにおける凹円錐台面状部23Bの上端位置が肩部6の上端位置と缶軸C方向に一致して第2の金型21Bがストロークエンド(下死点)に達したところで、円筒状部11Aの上端側部分は第2の金型21Bの小径円筒部25Bの内径d2と略等しい外径に絞り込まれてもう一段縮径された円筒状部11Bに成形される。 Next, when the first mold 21A is pulled out from the bottomed cylindrical body 10A and the second mold 21B is inserted, the upper end position of the concave conical base surface portion 23B in the second mold 21B is similarly the shoulder portion 6. When the second mold 21B reaches the stroke end (bottom dead point) in accordance with the upper end position and the can axis C direction, the upper end side portion of the cylindrical portion 11A is the small diameter cylindrical portion 25B of the second mold 21B. It is formed into a cylindrical portion 11B which is narrowed down to an outer diameter substantially equal to the inner diameter d2 of the above and is further reduced in diameter.

さらに、こうして縮径した円筒状部11Bの下端側部分から肩部6にかけては、円環部24bによって肩部6側に短い円筒状部11Aが残されるとともに、この円筒状部11Aの上端側には、第2の金型21Bの首部成形部24Bの断面形状を略転写したような外周面の断面形状を有する上記首部縮径部7aが形成される。これによって、図3(a)に示した有底円筒体10Aは、図6に示すような首部7を有する有底円筒体10Bに成形される。 Further, from the lower end side portion to the shoulder portion 6 of the cylindrical portion 11B whose diameter is reduced in this way, a short cylindrical portion 11A is left on the shoulder portion 6 side by the annular portion 24b, and a short cylindrical portion 11A is left on the upper end side of the cylindrical portion 11A. Is formed with the neck reduced diameter portion 7a having a cross-sectional shape of an outer peripheral surface that is substantially a transfer of the cross-sectional shape of the neck forming portion 24B of the second mold 21B. As a result, the bottomed cylinder 10A shown in FIG. 3A is formed into a bottomed cylinder 10B having a neck portion 7 as shown in FIG.

なお、このように段階的に縮径させられて成形される首部7の1段当たりの缶軸Cに対する直径方向の縮径量、すなわち図4に示す第1の金型21Aの円環部24bの内径(直径)d0と小径円筒部25Aの内径(直径)d1との差d0−d1と、この第1の金型21Aの小径円筒部25Aの内径(直径)d1と図5に示す第2の金型21Bの小径円筒部25Bの内径(直径)d2との差d1−d2は、それぞれ0.5mm〜1.5mmの範囲とされるのが望ましい。また、これら第1、第2の金型21A、21Bの首部成形部24A、24Bにおける傾斜部24dが缶軸Cに対してなす傾斜角αは18°〜25°の範囲とされるのが望ましい。 The amount of diameter reduction in the diameter direction with respect to the can shaft C per stage of the neck portion 7 formed by being gradually reduced in diameter, that is, the annular portion 24b of the first mold 21A shown in FIG. The difference d0-d1 between the inner diameter (diameter) d0 of the small diameter cylindrical portion 25A and the inner diameter (diameter) d1 of the small diameter cylindrical portion 25A, the inner diameter (diameter) d1 of the small diameter cylindrical portion 25A of the first mold 21A, and the second shown in FIG. It is desirable that the difference d1-d2 from the inner diameter (diameter) d2 of the small-diameter cylindrical portion 25B of the mold 21B is in the range of 0.5 mm to 1.5 mm, respectively. Further, it is desirable that the inclination angle α formed by the inclined portions 24d in the neck forming portions 24A and 24B of the first and second molds 21A and 21B with respect to the can shaft C is in the range of 18 ° to 25 °. ..

次に、こうして首部7が成形された図6および図7(a)に示す有底円筒体10Bの第2の金型21Bによって縮径された円筒状部11Bには、キャップ取付部成形工程において図7(b)および図8と図と9に示すような第1、第2の拡径工具31A、31Bが挿入されて首部7よりも上端側の部分が拡径され、膨出部8が成形される。 Next, in the cap mounting portion forming step, the cylindrical portion 11B whose diameter is reduced by the second mold 21B of the bottomed cylindrical body 10B shown in FIGS. 6 and 7 (a) in which the neck portion 7 is formed in this way is formed. The first and second diameter-expanding tools 31A and 31B as shown in FIGS. 7 (b), 8 and 8 and 9 are inserted to expand the diameter of the upper end side of the neck 7, and the bulging portion 8 is formed. It is molded.

そして、本実施形態では、このキャップ取付部成形工程においても、図8に示すような第1の拡径工具31Aと図9に示すような第2の拡径工具31Bとをこの順に上記円筒状部11Bに挿入することによって、この円筒状部11Bを複数回(2回)に分けて段階的に拡径して膨出部8を成形する。 Then, in the present embodiment, also in this cap mounting portion forming step, the first diameter-expanding tool 31A as shown in FIG. 8 and the second diameter-expanding tool 31B as shown in FIG. 9 are formed in the above-mentioned cylindrical shape in this order. By inserting it into the portion 11B, the cylindrical portion 11B is divided into a plurality of times (twice) and the diameter is gradually increased to form the bulging portion 8.

これら第1、第2の拡径工具31A、31Bは、外径が2段の略円筒状をなしていて、やはり缶軸Cと同軸に配置され、下端側の小径部32A、32Bの外径(直径)D0は互いに等しく、ボトルネック成形工程において縮径した円筒状部11Bの内周に嵌合可能な大きさとされるとともに、上端側の大径部33A、33Bの外径D1、D2は小径部32A、32Bの外径D0よりも大きくされている。 These first and second diameter-expanding tools 31A and 31B have a substantially cylindrical shape with two steps of outer diameters, are also arranged coaxially with the can shaft C, and have outer diameters of the small diameter portions 32A and 32B on the lower end side. (Diameter) D0 are equal to each other and have a size that can be fitted to the inner circumference of the cylindrical portion 11B whose diameter has been reduced in the bottleneck molding process, and the outer diameters D1 and D2 of the large diameter portions 33A and 33B on the upper end side are It is made larger than the outer diameter D0 of the small diameter portions 32A and 32B.

また、これら小径部32A、32Bと大径部33A、33Bとの間には、缶軸Cに沿った断面において図8(b)および図9(b)に拡大して示すように、上端側に向かうに従い外周側に向けて互いに等しい一定の傾斜角βで拡径する拡径部34A、34Bが形成されている。これらの拡径部34A、34Bは、小径部32A、32Bとは断面凹円弧等の凹曲部34aを介して接するとともに、大径部33A、33Bとは凹曲部34aよりも半径の大きな断面凸円弧等の凸曲部34bを介して接する断面直線状に形成されている。 Further, between the small diameter portions 32A and 32B and the large diameter portions 33A and 33B, the upper end side is shown enlarged in FIGS. 8 (b) and 9 (b) in the cross section along the can shaft C. The diameter-expanded portions 34A and 34B are formed so as to increase the diameter toward the outer peripheral side at a constant inclination angle β equal to each other. These enlarged diameter portions 34A and 34B are in contact with the small diameter portions 32A and 32B via a concave portion 34a such as a concave arc in cross section, and the large diameter portions 33A and 33B have a cross section having a larger radius than the concave portion 34a. It is formed in a straight cross section that is in contact with each other via a convex curved portion 34b such as a convex arc.

そして、本実施形態でも、これらの拡径部34A、34Bの缶軸C方向の長さが、第2の拡径工具31Bにおいて第1の拡径工具31Aよりも長くされており、これにより第2の拡径工具31Bの大径部33Bの外径(直径)D2は、第1の拡径工具31Aの大径部33Aの外径(直径)D1よりも大きくされている。なお、凹曲部34aと凸曲部34bの断面がなす円弧の半径と缶軸C方向の長さは、第1、第2の拡径工具31A、31B同士で互いに等しくされている。 Further, also in the present embodiment, the lengths of the diameter-expanded portions 34A and 34B in the can-axis C direction are made longer in the second diameter-expanding tool 31B than in the first diameter-expanding tool 31A. The outer diameter (diameter) D2 of the large diameter portion 33B of the diameter-expanding tool 31B of 2 is larger than the outer diameter (diameter) D1 of the large-diameter portion 33A of the first diameter-expanding tool 31A. The radius of the arc formed by the cross sections of the concave portion 34a and the convex portion 34b and the length in the can axis C direction are equal to each other between the first and second diameter-expanding tools 31A and 31B.

このような第1、第2の拡径工具31A、31Bのうち、まず第1の拡径工具31Aから図7に白抜き矢線で示すように缶軸Cと同軸に縮径した円筒状部11Bの内周に小径部32Aを摺接しつつ挿入すると、拡径部34Aから大径部33Aが形成された部分によって円筒状部11Bが上端側から拡径させられる。 Of the first and second diameter-expanding tools 31A and 31B, first, the first diameter-expanding tool 31A to the cylindrical portion whose diameter is reduced coaxially with the can shaft C as shown by the white arrow in FIG. When the small diameter portion 32A is inserted while sliding on the inner circumference of the 11B, the diameter of the cylindrical portion 11B is expanded from the upper end side by the portion where the large diameter portion 33A is formed from the enlarged diameter portion 34A.

本実施形態では、こうして挿入された小径部32Aの上端が首部7の首部縮径部7aの上端から缶軸C方向に僅かに上端側に間隔をあけた位置に配設されたところで第1の拡径工具31Aはストロークエンド(下死点)に達する。このとき、首部縮径部7aの上端側には縮径した円筒状部11Bが首部7に残され、そのさらに上端側に連なるように上端側に向かうに従い拡径する膨出部拡径部8aが拡径部34Aによって成形されて、この膨出部拡径部8aよりも上端側は大径部33Aの外径D1と略等しい内径の円筒状に成形される。 In the present embodiment, the first is where the upper end of the small diameter portion 32A inserted in this way is arranged at a position slightly spaced from the upper end of the neck reduced diameter portion 7a of the neck portion 7 toward the upper end side in the can axis C direction. The diameter expansion tool 31A reaches the stroke end (bottom dead center). At this time, a reduced diameter cylindrical portion 11B is left on the neck portion 7 on the upper end side of the neck portion reduced diameter portion 7a, and the diameter of the bulging portion enlarged portion 8a increases toward the upper end side so as to be continuous with the upper end side. Is formed by the diameter-expanded portion 34A, and the upper end side of the bulging portion-diameter-expanded portion 8a is formed into a cylindrical shape having an inner diameter substantially equal to the outer diameter D1 of the large-diameter portion 33A.

次に、第1の拡径工具31Aを引き抜いて第2の拡径工具31Bを小径部32Bから円筒状部11Bの内周に挿入すると、拡径部34Bから大径部33Bによって円筒状部11Bの上端側がもう一段拡径させられる。そして、こうして挿入された小径部32Bの上端の位置が、第1の拡径工具31Aのストロークエンドにおける小径部32Aの上端位置と缶軸C方向に等しい位置まで挿入されたところで、第2の拡径工具31Bはストロークエンド(下死点)に達する。 Next, when the first diameter-expanding tool 31A is pulled out and the second diameter-expanding tool 31B is inserted from the small-diameter portion 32B into the inner circumference of the cylindrical portion 11B, the cylindrical portion 11B is formed from the diameter-expanded portion 34B to the large-diameter portion 33B. The upper end side of is expanded one step further. Then, when the position of the upper end of the small diameter portion 32B inserted in this way is inserted to a position equal to the upper end position of the small diameter portion 32A at the stroke end of the first diameter expansion tool 31A in the can axis C direction, the second expansion is performed. The diameter tool 31B reaches the stroke end (bottom dead center).

従って、第1の拡径工具31Aによって成形された膨出部拡径部8aはさらに上端側に向かうに従い拡径するように延長されるとともに、この膨出部拡径部8aよりも上端側は大径部33Bの外径D2と略等しい内径の円筒状部11Cに成形される。これにより、図6および図7(a)に示した有底円筒体10Bは、図10に示すような有底円筒体10Cに成形される。 Therefore, the bulging portion diameter-expanded portion 8a formed by the first diameter-expanding tool 31A is extended so as to be further expanded toward the upper end side, and the upper end side of the bulging portion diameter-expanded portion 8a is further extended. It is formed into a cylindrical portion 11C having an inner diameter substantially equal to the outer diameter D2 of the large diameter portion 33B. As a result, the bottomed cylinder 10B shown in FIGS. 6 and 7A is formed into the bottomed cylinder 10C as shown in FIG.

なお、このように段階的に拡径させられて成形される膨出部8の1段当たりの缶軸Cに対する直径方向の拡径量、すなわち図8に示す第1の拡径工具31Aの小径部32Aの外径(直径)D0と大径部33Aの外径(直径)D1との差D1−D0と、この第1の拡径工具31Aの大径部33Aの外径(直径)D1と図9に示す第2の拡径工具31Bの大径部33Bの外径(直径)D2との差D2−D1は、それぞれ0.5mm〜1.5mmの範囲とされるのが望ましい。また、これら第1、第2の拡径工具31A、31Bの拡径部34A、34Bが缶軸Cに対してなす傾斜角βは15°〜35°の範囲とされるのが望ましい。 The amount of diameter expansion in the diameter direction with respect to the can shaft C per stage of the bulging portion 8 formed by gradually expanding the diameter in this way, that is, the small diameter of the first diameter expansion tool 31A shown in FIG. The difference D1-D0 between the outer diameter (diameter) D0 of the portion 32A and the outer diameter (diameter) D1 of the large diameter portion 33A, and the outer diameter (diameter) D1 of the large diameter portion 33A of the first diameter expansion tool 31A. It is desirable that the difference D2-D1 from the outer diameter (diameter) D2 of the large diameter portion 33B of the second diameter-expanding tool 31B shown in FIG. 9 is in the range of 0.5 mm to 1.5 mm, respectively. Further, it is desirable that the inclination angle β formed by the diameter-expanded portions 34A and 34B of the first and second diameter-expanding tools 31A and 31B with respect to the can shaft C is in the range of 15 ° to 35 °.

こうして首部7の上端側に膨出部8が形成されるとともに、この膨出部8の上端側に拡径させられた円筒状部11Cが成形された有底円筒体10Cは、この拡径させられた円筒状部11Cの上端側が上述のようにねじ切り加工等が施されることによりキャップ取付部9が形成されて縮径されるとともに、下端側には縮径されずに膨出部8が残される。さらに、このキャップ取付部9の開口部4にはカール部が形成されるなどして、図1に示したようなボトル缶の缶本体1に成形される。 In this way, the bulging portion 8 is formed on the upper end side of the neck portion 7, and the bottomed cylindrical body 10C on which the cylindrical portion 11C whose diameter is expanded on the upper end side of the bulging portion 8 is formed is expanded in diameter. The upper end side of the formed cylindrical portion 11C is threaded as described above to form the cap mounting portion 9 and reduce the diameter, and the bulging portion 8 is formed on the lower end side without being reduced in diameter. Be left behind. Further, a curl portion is formed in the opening 4 of the cap mounting portion 9, and the cap body 1 is formed into a bottle can body 1 as shown in FIG.

このようなボトル缶の製造方法においては、有底円筒体10A、10Bにおける円筒状部11A、11Bの首部7の縮径や膨出部8の拡径が複数回に分けて段階的に行われるので、個々の段階における縮径量や拡径量は少なくすることができる。このため、特に首部7が上端側に向かうに従い縮径する首部縮径部7aや膨出部8が上端側に向かうに従い拡径する膨出部拡径部8aを有している場合に、有底円筒体10A、10Bに缶軸C方向に作用する荷重を軽減することができる。 In such a method for manufacturing a bottle can, the diameter of the neck portion 7 of the cylindrical portions 11A and 11B of the bottomed cylindrical bodies 10A and 10B and the diameter of the bulging portion 8 are gradually increased in a plurality of times. Therefore, the amount of diameter reduction and the amount of diameter expansion at each stage can be reduced. For this reason, it is particularly present when the neck portion 7 has a diameter-reduced portion 7a of the neck portion whose diameter is reduced toward the upper end side and the bulging portion 8 has a bulging portion diameter-expanded portion 8a whose diameter is increased toward the upper end side. The load acting on the bottom cylinders 10A and 10B in the can axis C direction can be reduced.

従って、本実施形態のように、カップ状素材に成形される金属板の板厚が0.230mm〜0.300mmと薄く、またこのカップ状素材からDIプレス工程を経て成形された有底円筒体における円筒状部の上端側部分の厚さも0.180mm〜0.225mmと薄くて、さらにこの円筒部の下端側部分の厚さはこれよりも薄い場合であっても、首部7の成形の際の荷重によって有底円筒体10A、10Bに座屈が生じるのを防ぐことができる。また、膨出部8を成形する際の荷重によって円筒状部11Cに割れが生じるのも防ぐことができる。このため、上記構成のボトル缶の製造方法によれば、このような座屈や割れによるボトル缶の製造歩留まりや製造効率等の低下を招くことなく、ボトル缶の缶本体1のさらなる薄肉化を図ることができるので、より一層の省資源化や省エネルギー化を促すことが可能となる。 Therefore, as in the present embodiment, the thickness of the metal plate formed into the cup-shaped material is as thin as 0.230 mm to 0.300 mm, and the bottomed cylinder formed from this cup-shaped material through the DI press process. The thickness of the upper end side portion of the cylindrical portion is as thin as 0.180 mm to 0.225 mm, and even if the thickness of the lower end side portion of the cylindrical portion is thinner than this, when the neck portion 7 is formed. It is possible to prevent buckling of the bottomed cylinders 10A and 10B due to the load of. Further, it is possible to prevent the cylindrical portion 11C from being cracked due to the load when the bulging portion 8 is formed. Therefore, according to the method for manufacturing a bottle can having the above configuration, the can body 1 of the bottle can can be further thinned without causing a decrease in the manufacturing yield and manufacturing efficiency of the bottle can due to such buckling and cracking. Since it can be planned, it is possible to promote further resource saving and energy saving.

なお、このようなボトル缶の缶本体に有底円筒体を経て成形される上記金属板は、JIS H 4000におけるA3004またはA3104のアルミニウム合金であって、205℃×20分ベーキング後の0.2%耐力が235N/mm〜265N/mmの範囲であることが望ましい。この205℃×20分ベーキング後の0.2%耐力が235N/mmを下回ると、上述のように縮径や拡径を複数回に分けて段階的に行っても首部7や膨出部8の成形の際に有底円筒体10A、10Bの座屈や割れが生じるおそれがあり、また逆に265N/mmを上回っても、成形に必要な荷重が大きくなって荷重制御が困難となり、やはり座屈や割れを生じ易くなるおそれがある。 The metal plate formed on the main body of such a bottle can via a bottomed cylinder is an aluminum alloy of A3004 or A3104 in JIS H 4000, and is 0.2 at 205 ° C. × 20 minutes after baking. It is desirable that the% proof stress is in the range of 235 N / mm 2 to 265 N / mm 2. When the 0.2% proof stress after baking at 205 ° C. × 20 minutes is less than 235 N / mm 2 , the neck portion 7 and the bulging portion can be reduced or expanded in multiple steps as described above. Buckling or cracking of the bottomed cylindrical bodies 10A and 10B may occur during molding of 8, and conversely, even if the amount exceeds 265 N / mm 2 , the load required for molding becomes large and load control becomes difficult. After all, buckling and cracking may easily occur.

また、本実施形態では、首部7の縮径および膨出部8の拡径をそれぞれ2回に分けて段階的に行っているが、3回以上の回数で段階的に行ってもよい。ただし、これら縮径や拡径を行うときの回数が多くなりすぎると製造効率が損なわれるので、段階的に行う場合の回数は3回以下とされるのが望ましい。 Further, in the present embodiment, the diameter reduction of the neck portion 7 and the diameter expansion of the bulging portion 8 are each divided into two steps and performed stepwise, but the diameter may be stepwise performed three or more times. However, if the number of times the diameter is reduced or expanded is too large, the manufacturing efficiency is impaired. Therefore, it is desirable that the number of times the diameter is reduced or increased stepwise is 3 or less.

さらに、各段階の縮径量や拡径量の差が大きすぎると、大きな縮径量または拡径量の成形の際の座屈を確実に防ぐことができなくなるおそれがあるので、これら各段階の縮径量や拡径量は上述した範囲内にあるのが望ましく、互いに等しい縮径量や拡径量であるのがより望ましい。なお、首部7の縮径量や膨出部8の拡径量によっては、縮径と拡径の一方だけを複数回に分けて段階的に行い、他方は1回の縮径や拡径だけで成形するようにしてもよい。 Further, if the difference between the diameter reduction amount and the diameter expansion amount in each stage is too large, it may not be possible to reliably prevent buckling during molding of a large diameter reduction amount or diameter expansion amount. It is desirable that the diameter reduction amount and the diameter expansion amount of the above range are within the above-mentioned ranges, and it is more desirable that the diameter reduction amount and the diameter expansion amount are equal to each other. Depending on the amount of diameter reduction of the neck portion 7 and the amount of diameter expansion of the bulging portion 8, only one of the diameter reduction and the diameter expansion is divided into a plurality of times and the other is performed only once. It may be molded with.

次に、本発明の実施例を挙げて、本発明の効果について説明する。本実施例では、JIS H 4000におけるA3104のアルミニウム合金であって、205℃×20分ベーキング後の0.2%耐力が254.8N/mm、板厚0.300mmの金属板からカッピングプレス工程においてカップ状素材を成形し、さらにDIプレス工程において底部と円筒部とを有する有底円筒体を成形した。 Next, the effect of the present invention will be described with reference to examples of the present invention. In this embodiment, it is an aluminum alloy of A3104 in JIS H 4000, and a cutting press process is performed from a metal plate having a 0.2% proof stress of 254.8 N / mm 2 and a plate thickness of 0.300 mm after baking at 205 ° C. In, a cup-shaped material was formed, and in a DI pressing step, a bottomed cylindrical body having a bottom portion and a cylindrical portion was formed.

次いで、この有底円筒体にボトルネック成形工程において肩部6を形成して図3(a)に示すような円筒状部11Aを有する有底円筒体10Aを成形した後、この円筒状部11Aに第1、第2の2つの金型21A、21Bによって2回の縮径を行い、図6に示す有底円筒体10Bのような首部縮径部7aを有する首部7を成形した。 Next, a shoulder portion 6 is formed on the bottomed cylindrical body in the bottleneck molding step to form a bottomed cylindrical body 10A having a cylindrical portion 11A as shown in FIG. 3A, and then the cylindrical portion 11A is formed. The diameter was reduced twice by the first and second dies 21A and 21B, and the neck portion 7 having the neck diameter-reduced portion 7a like the bottomed cylindrical body 10B shown in FIG. 6 was formed.

なお、これら第1、第2の金型21A、21Bにおいて、首部成形部24A、24Bにおける傾斜部24dの缶軸Cに対する傾斜角αはともに20°であり、第1の金型21Aの円環部24bの内径(直径)d0と小径円筒部25Aの内径(直径)d1との差d0−d1は1.1mm、この第1の金型21Aの小径円筒部25Aの内径(直径)d1との第2の金型21Bの小径円筒部25Bの内径(直径)d2の差d1−d2も同じく1.1mmであって、円筒状部11Aの外径(直径)の総縮径量は2.2mmであった。これを実施例1とする。 In these first and second molds 21A and 21B, the inclination angle α of the inclined portion 24d of the neck forming portions 24A and 24B with respect to the can shaft C is 20 °, and the ring of the first mold 21A is formed. The difference d0-d1 between the inner diameter (diameter) d0 of the portion 24b and the inner diameter (diameter) d1 of the small diameter cylindrical portion 25A is 1.1 mm, which is the same as the inner diameter (diameter) d1 of the small diameter cylindrical portion 25A of the first mold 21A. The difference d1-d2 of the inner diameter (diameter) d2 of the small diameter cylindrical portion 25B of the second mold 21B is also 1.1 mm, and the total diameter reduction amount of the outer diameter (diameter) of the cylindrical portion 11A is 2.2 mm. Met. This is referred to as Example 1.

また、この実施例1に対する比較例として、円環部24bの内径(直径)d0と小径円筒部25Bの内径(直径)d2との差d0−d2が上記総縮径量と等しい2.2mmとなる第2の金型21Bを単一で用いて、1回の縮径により有底円筒体10Aの円筒状部11Aの外径(直径)を2.2mm縮径して首部7を成形した。これを比較例1とする。そして、これら実施例1と比較例1とによる首部7の成形の際の成形荷重を測定するとともに、100個の有底円筒体10Aに首部7を成形したときに座屈が生じた有底円筒体10Aの数を確認した。この結果を、縮径量とともに表1に示す。 Further, as a comparative example with respect to the first embodiment, the difference d0-d2 between the inner diameter (diameter) d0 of the annular portion 24b and the inner diameter (diameter) d2 of the small diameter cylindrical portion 25B is 2.2 mm, which is equal to the total diameter reduction amount. The neck portion 7 was formed by reducing the outer diameter (diameter) of the cylindrical portion 11A of the bottomed cylindrical body 10A by 2.2 mm by using a single second mold 21B. This is referred to as Comparative Example 1. Then, the forming load at the time of forming the neck portion 7 according to the first embodiment and the first comparative example is measured, and the bottomed cylinder in which buckling occurs when the neck portion 7 is formed into 100 bottomed cylinders 10A. The number of bodies 10A was confirmed. The results are shown in Table 1 together with the amount of diameter reduction.

なお、DIプレス工程において成形された有底円筒体は、円筒部の直径(缶本体1の胴部5の直径)が約66mmであり、この円筒部の上端側部分の厚さは実施例1および比較例1ともに0.200mmであった。また、この有底円筒体にボトルネック成形工程において肩部6が成形された図3(a)に示した有底円筒体10Aは、底部2の下端から円筒部の上端までの缶軸C方向の高さが137mm、底部2の下端から肩部6の上端までの缶軸C方向の高さが105mm、肩部6の上端側に成形された縮径した円筒状部11Aの外径(直径)は38mmであった。 The bottomed cylindrical body formed in the DI press step has a diameter of the cylindrical portion (diameter of the body portion 5 of the can body 1) of about 66 mm, and the thickness of the upper end side portion of the cylindrical portion is the thickness of the first embodiment. And Comparative Example 1 was 0.200 mm. Further, the bottomed cylinder 10A shown in FIG. 3A in which the shoulder portion 6 is formed on the bottomed cylinder in the bottleneck molding step is in the can axis C direction from the lower end of the bottom portion 2 to the upper end of the cylindrical portion. The height is 137 mm, the height from the lower end of the bottom 2 to the upper end of the shoulder 6 in the can axis C direction is 105 mm, and the outer diameter (diameter) of the reduced cylindrical portion 11A formed on the upper end side of the shoulder 6. ) Was 38 mm.

Figure 2021035696
Figure 2021035696

この表1の結果より、首部7の成形を1回で行う比較例1では、成形荷重が2100Nと大きく、これに伴い100個の有底円筒体10A中で座屈する有底円筒体10Aが15個と多く、ボトルネッカーによって首部7を成形する際に頻繁に装置の停止を余儀なくされることが分かる。これに対して、首部7の成形を2回に分けて行う実施例1では、1回当たりの成形荷重は比較例1よりも大幅に小さくて有底円筒体10Aへの負荷が小さく、座屈する有底円筒体10Aも0個であったことから、ボトルネッカーによる首部7の成形を円滑かつ効率的に行うことができるとともに、製造歩留まりの向上を図ることが可能となる。 From the results in Table 1, in Comparative Example 1 in which the neck portion 7 is molded at one time, the molding load is as large as 2100 N, and the bottomed cylinder 10A that buckles in 100 bottomed cylinders 10A is 15 as a result. It can be seen that the number of pieces is large, and the device is frequently forced to stop when the neck portion 7 is formed by the bottle necker. On the other hand, in the first embodiment in which the molding of the neck portion 7 is performed in two times, the molding load per one time is significantly smaller than that in the comparative example 1, the load on the bottomed cylindrical body 10A is small, and the bottomed cylinder 10A buckles. Since the number of the bottomed cylindrical bodies 10A is 0, the neck portion 7 can be formed smoothly and efficiently by the bottle necker, and the manufacturing yield can be improved.

次に、こうして首部7が成形された図6に示すような有底円筒体10Bの円筒状部11Bに、この首部7から上端側の部分を複数回に分けて段階的に拡径することによって膨出部8を成形した。このとき、まず実施例2として、上記実施形態と同様に第1、第2の2つの拡径工具31A、31Bによって2回の拡径を行い、さらに実施例3として、第1ないし第3の3つの拡径工具によって3回の拡径を行い、実施例2と等しい拡径量で拡径する膨出部8を成形した。 Next, in the cylindrical portion 11B of the bottomed cylindrical body 10B as shown in FIG. 6 in which the neck portion 7 is formed, the diameter of the portion on the upper end side from the neck portion 7 is gradually expanded in a plurality of times. The bulging portion 8 was formed. At this time, first, as the second embodiment, the diameter is expanded twice by the first and second two diameter-expanding tools 31A and 31B as in the above embodiment, and further, as the third embodiment, the first to third diameter-expanding tools 31A and 31B are used. The diameter was expanded three times with three diameter expansion tools, and the bulging portion 8 was formed to expand the diameter with the same diameter expansion amount as in Example 2.

なお、これら第1、第2の拡径工具31A、31Bおよび第3の拡径工具における拡径部34A、34Bが缶軸Cに対してなす傾斜角βは20°であり、実施例2における第1の拡径工具31Aの小径部32Aの外径(直径)D0と大径部33Aの外径(直径)D1との差D1−D0と、第1の拡径工具31Aの大径部33Aの外径(直径)D1と第2の拡径工具31Bの大径部33Bの外径(直径)D2との差D2−D1は、それぞれ1.0mmであって、総拡径量は2.0mmであった。 The inclination angle β formed by the diameter-expanded portions 34A and 34B of the first and second diameter-expanding tools 31A and 31B and the third diameter-expanding tool with respect to the can shaft C is 20 °, and the second embodiment The difference D1-D0 between the outer diameter (diameter) D0 of the small diameter portion 32A of the first diameter-expanding tool 31A and the outer diameter (diameter) D1 of the large-diameter portion 33A, and the large-diameter portion 33A of the first diameter-expanding tool 31A. The difference D2-D1 between the outer diameter (diameter) D1 of the above and the outer diameter (diameter) D2 of the large diameter portion 33B of the second diameter expansion tool 31B is 1.0 mm, respectively, and the total diameter expansion amount is 2. It was 0 mm.

また、実施例3における第1の拡径工具31Aの小径部32Aの外径(直径)D0と大径部33Aの外径(直径)D1との差D1−D0と、第1の拡径工具31Aの大径部33Aの外径(直径)D1と第2の拡径工具31Bの大径部33Bの外径(直径)D2との差D2−D1はそれぞれ0.7mmであり、第3の拡径工具の大径部の外径(直径)と第2の拡径工具31Bの大径部33Bの外径(直径)D2との差は0.6mmで、総拡径量を2.0mmとした。 Further, the difference D1-D0 between the outer diameter (diameter) D0 of the small diameter portion 32A of the first diameter expansion tool 31A and the outer diameter (diameter) D1 of the large diameter portion 33A in the third embodiment and the first diameter expansion tool The difference D2-D1 between the outer diameter (diameter) D1 of the large diameter portion 33A of 31A and the outer diameter (diameter) D2 of the large diameter portion 33B of the second expansion tool 31B is 0.7 mm, respectively, and the third The difference between the outer diameter (diameter) of the large diameter part of the diameter expansion tool and the outer diameter (diameter) D2 of the large diameter part 33B of the second diameter expansion tool 31B is 0.6 mm, and the total diameter expansion amount is 2.0 mm. And said.

さらに、これら実施例2、3に対する比較例2として、やはり実施例2、3と等しい総拡径量の膨出部8の成形を、実施例2の第2の拡径工具31Bと同じ単一の拡径工具による1回の拡径によって行い、その際の成形荷重を測定するとともに、100個の有底円筒体10Bに膨出部8を成形したときに割れが生じた有底円筒体10Bの数を確認した。この結果を、個々の拡径工具による拡径量とともに表2に示す。 Further, as Comparative Example 2 with respect to Examples 2 and 3, the molding of the bulging portion 8 having the same total diameter expansion amount as in Examples 2 and 3 is the same as that of the second diameter expansion tool 31B of Example 2. The bottomed cylinder 10B was cracked when the bulge 8 was molded into 100 bottomed cylinders 10B while measuring the molding load at that time by expanding the diameter once with the diameter expansion tool. I checked the number of. The results are shown in Table 2 together with the amount of diameter expansion by each diameter expansion tool.

Figure 2021035696
Figure 2021035696

従って、この表2の結果からも、膨出部8の成形を1回で行う比較例2では、成形荷重が1800Nと大きく、これに伴い100個の有底円筒体10B中で割れが生じた有底円筒体10Bも13個と多くて、ボトルネッカーによる成形する際に頻繁な停止を余儀なくされる。これに対して、膨出部8の成形を複数回に分けて段階的に行う実施例2、3では、1回当たりの成形荷重は比較例2よりも小さく、特に3回で行う実施例3では成形荷重が大幅に小さく、またいずれも割れが生じた有底円筒体10Bが0個であったことから、ボトルネッカーによる製造効率や製造歩留まりの向上を図ることが可能となる。 Therefore, from the results in Table 2, in Comparative Example 2 in which the bulging portion 8 is molded at one time, the molding load is as large as 1800 N, and as a result, cracks occur in the 100 bottomed cylinders 10B. There are as many as 13 bottomed cylindrical bodies 10B, and frequent stops are unavoidable when molding with a bottle necker. On the other hand, in Examples 2 and 3 in which the molding of the bulging portion 8 is performed stepwise by dividing into a plurality of times, the molding load per one time is smaller than that in Comparative Example 2, and in particular, Example 3 in which the molding is performed three times. Since the molding load was significantly small and the number of cracked bottomed cylindrical bodies 10B was 0, it is possible to improve the manufacturing efficiency and the manufacturing yield by the bottle necker.

1 缶本体
2 底部
3 外周部
4 開口部
5 胴部
6 肩部
7 首部
7a 首部縮径部
8 膨出部
8a 膨出部拡径部
9 キャップ取付部
10A〜10C 有底円筒体
11A〜11C 円筒状部
21A 第1の金型
21B 第2の金型
24A、24B 首部成形部
24d 傾斜部
31A 第1の拡径工具
31B 第2の拡径工具
34A、34B 拡径部
C 缶軸
α 首部縮径部7aの缶軸Cに対する傾斜角
β 膨出部拡径部8aの缶軸Cに対する傾斜角
d0 円環部24bの内径(縮径前の円筒状部11Aの直径)
d1 第1の金型21Aにおける小径円筒部25Aの内径(第1の金型21Aによって縮径した円筒状部11Aの直径)
d2 第2の金型21Bにおける小径円筒部25Bの内径(第2の金型21Bによって縮径した円筒状部11Aの直径)
D0 第1、第2の拡径工具31A、31Bの小径部32A、32Bの外径(拡径前の円筒状部11Bの内径)
D1 第1の拡径工具31Aの大径部33Aの外径(第1の拡径工具31Aによって拡径した円筒状部11Bの内径)
D2 第2の拡径工具31Bの大径部33Bの外径(第2の拡径工具31Bによって拡径した円筒状部11Bの内径)
1 Can body 2 Bottom 3 Outer circumference 4 Opening 5 Body 6 Shoulder 7 Neck 7a Neck diameter reduction 8 Swelling 8a Swelling diameter expansion 9 Cap mounting 10A-10C Bottomed cylinder 11A-11C Cylindrical Shape 21A 1st mold 21B 2nd mold 24A, 24B Neck molding part 24d Inclined part 31A 1st diameter expansion tool 31B 2nd diameter expansion tool 34A, 34B Diameter expansion part C Can shaft α Neck diameter reduction Inclination angle of part 7a with respect to can shaft C β Inclination angle of bulging portion 8a with respect to can shaft d d0 Inner diameter of annular portion 24b (diameter of cylindrical portion 11A before diameter reduction)
d1 Inner diameter of the small-diameter cylindrical portion 25A in the first mold 21A (diameter of the cylindrical portion 11A reduced in diameter by the first mold 21A)
d2 Inner diameter of the small diameter cylindrical portion 25B in the second mold 21B (diameter of the cylindrical portion 11A reduced in diameter by the second mold 21B)
D0 Outer diameters of the small diameter portions 32A and 32B of the first and second diameter expansion tools 31A and 31B (inner diameter of the cylindrical portion 11B before diameter expansion)
D1 Outer diameter of the large diameter portion 33A of the first diameter-expanding tool 31A (inner diameter of the cylindrical portion 11B expanded by the first diameter-expanding tool 31A)
D2 Outer diameter of the large diameter portion 33B of the second diameter-expanding tool 31B (inner diameter of the cylindrical portion 11B expanded by the second diameter-expanding tool 31B)

Claims (4)

缶本体の底部と一体に成形される外周部に、上記底部から上記缶本体の上端開口部に向けて順に缶軸を中心とした円筒状の胴部と、上端側に向かうに従い縮径する肩部と、この肩部からさらに上端側に向かって延びる首部と、キャップ取付部とが形成されたボトル缶の製造方法であって、
金属板から絞り加工により成形されたカップ状素材に再絞りおよびしごき加工と底部成形加工を施して、上記底部と、上記胴部と同外径の円筒部が形成された有底円筒体を成形するDIプレス工程と、
この有底円筒体の上記円筒部の上端側部分を縮径させることにより、上記肩部と、この肩部から上端側に向かうに従いさらに縮径する上記首部とを成形するボトルネック成形工程と、
上記首部の上端部に上記キャップ取付部を成形するキャップ取付部成形工程とを備え、
上記ボトルネック成形工程においては、上記肩部の上端側に形成された円筒状部のうち上記肩部との接続部分を除いた部分を直径d0から直径d2まで複数回に分けて段階的に縮径することによって上記首部を成形する構成とされており、1回の縮径量が0.5mm〜1.5mmの範囲内とされていることを特徴とするボトル缶の製造方法。
On the outer peripheral portion that is integrally molded with the bottom of the can body, a cylindrical body centered on the can shaft in order from the bottom to the upper end opening of the can body, and a shoulder that shrinks in diameter toward the upper end side. A method for manufacturing a bottle can in which a portion, a neck portion extending from the shoulder portion toward the upper end side, and a cap mounting portion are formed.
A cup-shaped material formed by drawing from a metal plate is re-drawn, squeezed, and bottom-formed to form a bottomed cylindrical body in which a bottom portion and a cylindrical portion having the same outer diameter as the body portion are formed. DI press process and
A bottleneck molding step of forming the shoulder portion and the neck portion whose diameter is further reduced toward the upper end side from the shoulder portion by reducing the diameter of the upper end side portion of the cylindrical portion of the bottomed cylinder.
A cap mounting portion molding step for molding the cap mounting portion is provided at the upper end portion of the neck portion.
In the bottleneck molding step, the portion of the cylindrical portion formed on the upper end side of the shoulder portion excluding the connecting portion with the shoulder portion is gradually shrunk from diameter d0 to diameter d2 in a plurality of times. A method for manufacturing a bottle can, which is configured to form the neck portion by measuring the diameter, and the amount of reduction in diameter at one time is within the range of 0.5 mm to 1.5 mm.
上記カップ状素材から成形される上記有底円筒体は、上記円筒部の上端側部分の厚さが0.180mm〜0.225mmであることを特徴とする請求項1に記載のボトル缶の製造方法。 The production of a bottle can according to claim 1, wherein the bottomed cylindrical body formed from the cup-shaped material has a thickness of an upper end side portion of the cylindrical portion of 0.180 mm to 0.225 mm. Method. 上記カップ状素材に成形される上記金属板は板厚0.230mm〜0.300mmであることを特徴とする請求項1または請求項2に記載のボトル缶の製造方法。 The method for producing a bottle can according to claim 1 or 2, wherein the metal plate formed into the cup-shaped material has a plate thickness of 0.230 mm to 0.300 mm. 上記金属板は、JIS H 4000におけるA3004またはA3104のアルミニウム合金であって、205℃×20分ベーキング後の0.2%耐力が235N/mm〜265N/mmの範囲であることを特徴とする請求項1から請求項3のいずれか一項に記載のボトル缶の製造方法。 The metal plate is an aluminum alloy of A3004 or A3104 in JIS H 4000, and is characterized in that the 0.2% proof stress after baking at 205 ° C. × 20 minutes is in the range of 235 N / mm 2 to 265 N / mm 2. The method for manufacturing a bottle can according to any one of claims 1 to 3.
JP2020184600A 2020-11-04 2020-11-04 Bottle can manufacturing method Active JP7112648B2 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5297414A (en) * 1992-09-30 1994-03-29 Reynolds Metals Company Method for necking containers
US5572893A (en) * 1994-12-01 1996-11-12 Goda; Mark E. Method of necking and impact extruded metal container
US5713235A (en) * 1996-08-29 1998-02-03 Aluminum Company Of America Method and apparatus for die necking a metal container

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5297414A (en) * 1992-09-30 1994-03-29 Reynolds Metals Company Method for necking containers
US5572893A (en) * 1994-12-01 1996-11-12 Goda; Mark E. Method of necking and impact extruded metal container
US5713235A (en) * 1996-08-29 1998-02-03 Aluminum Company Of America Method and apparatus for die necking a metal container

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