JP7262344B2 - bottle can - Google Patents

Description

The present invention is a metal can body in which a cylindrical cap mounting portion having a male screw portion and a bulging portion to which a cap is attached is formed at the upper end portion of a bottomed cylindrical can body centered on the can axis. It relates to bottle cans.

As such a bottle-shaped can, for example, Patent Document 1 discloses a cylindrical body, a shoulder section in the upper part of the body section, which is inclined with respect to the can axis and whose diameter is reduced upward, and the shoulder section. consists of a cylindrical mouth portion (cap attachment portion) extending upward, the mouth portion comprising a base portion connected to the upper end of the shoulder portion, a skirt valley portion connected to the base portion, and the skirt A metal such as aluminum having a skirt portion (bulging portion) connected to the valley portion and a screw portion (male screw portion) connected to the skirt portion is described. Here, in FIG. 1 of Patent Document 1, the terminal end (lower end) of the male screw portion reaches into the bulging portion in the can axial direction.

After the inside of such a bottle-can is filled with a beverage or the like, the cap mounting portion is covered with a cap made of metal such as aluminum, and the cap is drawn by applying a load in the axial direction of the can by a block. A load is applied to the inner periphery of the cap in a direction perpendicular to the can axis by a thread roller to form a female threaded portion so as to follow the male threaded portion, and a skirt roller is used to form the open end of the lower end of the cap. is pressed to the inner peripheral side, it is wound and sealed by the diameter-reduced portion below the bulging portion.

JP 2016-196332 A

By the way, in recent years, in such bottle cans, there has been a demand for a lighter can body in order to conserve the resources of the metal material forming the can body and to save energy in the material manufacturing process. Even if it is possible to make it possible, it is possible to significantly save resources and energy, or to reduce the cost of the can itself, in the huge number of bottle cans on the market. Here, in order to reduce the weight of the can body, it is conceivable to reduce the original plate thickness of the metal plate formed into the can body, thereby thinning the body portion, the shoulder portion, and the cap attaching portion. .

However, in such a thin-walled bottle can, if the terminal end of the male threaded portion reaches the bulging portion as described in Patent Document 1, the bulging portion is an enlarged diameter portion that bulges downward. The length in the direction of the can axis becomes uneven in the circumferential direction, the enlarged diameter part becomes short near the terminal end of the male screw part, and the cross section of the enlarged diameter part along the can axis forms an inclination with respect to the can axis Since the angle becomes large, the buckling strength in the can axial direction cannot be ensured, and there is a possibility that local buckling may occur in the cap mounting portion when the cap is drawn during capping.

When such local buckling occurs, the portion where the buckling occurs becomes the starting point, and the skirt roller is used to wind the open end of the cap onto the reduced diameter portion of the bulging portion, thereby resisting the pressing force. It cannot be completely tightened, and deformation occurs in the male threaded portion. If the male threaded portion is deformed in this manner, the rotational torque (reseal torque) increases when the cap is once removed from the cap attachment portion and then screwed onto the male threaded portion to attach the cap. may not be able to reseal.

The present invention has been made under such a background, and is capable of securing the buckling strength of the cap attachment portion in the can axial direction even for a thin-walled bottle can, thereby increasing the resealing torque. To provide a bottle-can capable of preventing resealing from becoming impossible.

In order to solve the above-mentioned problems and achieve such objects, the present invention provides a cylindrical cap attachment portion to which a cap is attached at the upper end of a bottomed cylindrical can body centered on the can axis. The cap attaching portion has a male threaded portion on the upper end side, and the cap attachment portion expands toward the outer peripheral side toward the lower end side and then reduces in diameter to form the lower end of the cap. The open end of the bulging portion has the same cross section along the can axis over the entire periphery of the can axis, and the male screw portion and the can axis The bulging portion has an enlarged diameter portion on the upper end side that swells toward the outer peripheral side as it goes linearly downward in a cross section along the can axis, and has an enlarged diameter portion on the lower end side that is aligned with the can axis. A diameter-reduced portion whose diameter decreases linearly downward in a cross-section along the length thereof, wherein the inclination angle of the enlarged-diameter portion with respect to the can axis is 3° to 30°, and the inclination of the diameter-reduced portion with respect to the can axis is set. The angle is 40° to 50°, the lower end of the male screw portion does not reach the bulging portion, and the length of the enlarged diameter portion in the can axis direction extends along the entire circumference of the can axis. In addition to being uniform over the can axis, the angle of inclination of the enlarged diameter portion with respect to the can axis in a cross section along the can axis is also constant over the entire circumference of the can axis. do.

In the bottle-shaped can configured in this way, the male threaded portion of the cap attachment portion is separated from the bulging portion in the can axial direction without reaching the bulging portion. is the same over the entire circumference of the can axis, and the length in the can axis direction of the enlarged diameter portion that bulges downward from the bulging portion is uniform. is also constant with respect to the can axis. For this reason, the buckling strength of the bulging portion in the direction of the can axis can be made uniform over the entire circumference of the can axis, and the load of the drawing process during capping causes local bearings on the cap mounting portion. You can prevent bending.

Therefore, when the open end of the cap is pressed by the skirt roller and wound around the diameter-reduced portion of the bulging portion, it is possible to prevent deformation of the male thread portion caused by such local buckling as a starting point. can be done. Therefore, it is possible to prevent the cap from being resealed once removed due to such deformation of the male screw portion, and to prevent an increase in the resealing torque, thereby impairing the resealing property. Therefore, it is possible to surely reduce the wall thickness of the bottle-can.

Further, in the present invention, the bulging portion has, on the upper end side, an enlarged diameter portion that bulges toward the outer peripheral side in a straight line downward in a cross section along the can axis. With such an angle range, the buckling strength of the bulging portion is further improved. It is more preferable that the angle of inclination of the enlarged diameter portion with respect to the can axis C is 5° to 15°.

Further, in the present invention, the lower end side of the bulging portion is provided with a diameter-reduced portion whose diameter decreases linearly downward in a cross-section along the can axis, and the inclination angle of the diameter-reduced portion with respect to the can axis. is 40° to 50°. Such an angular range is suitable for skirting the open end of the cap.

INDUSTRIAL APPLICABILITY As described above, according to the present invention, it is possible to prevent local buckling of the cap mounting portion during capping even when the thickness of the bottle can is reduced, and the open end portion of the cap can be prevented from buckling. It is possible to prevent deformation of the male threaded portion due to seaming, thereby preventing an increase in the resealing torque of the cap and an inability to reseal the cap.

It is a side view which shows the 1st reference example in describing embodiment of this invention. FIG. 2 is a cross-sectional view of a cap mounting portion of the reference example shown in FIG. 1; FIG. 11 is a side view showing a cap mounting portion of a second reference example of the present invention; FIG. 4 is a cross-sectional view of the cap mounting portion of the reference example shown in FIG. 3; It is a partially broken side view which shows the 3rd reference example of this invention. FIG. 11 is a side view showing a cap mounting portion of a fourth reference example of the present invention;

1 and 2 show a first reference example for describing one embodiment of the present invention. In the bottle can of this reference example , the can body 1 includes a bottom portion 2 and an outer peripheral portion 3 formed integrally with the bottom portion 2 and extending from the outer peripheral edge of the bottom portion 2 to the upper end side (upper side in FIGS. 1 and 2). It has a substantially multistage bottomed cylindrical shape centered on the can axis C. A dome portion 2a having a substantially arcuate cross-section is formed in the center of the bottom portion 2 and recessed inward in the direction of the can axis C (upper end side of the can body 1). An annular projection 2b protruding outward (lower end side of the can body 1) is continuously formed in the circumferential direction around the can axis C (see FIG. 5).

In addition, on the outer peripheral portion 3, a cylindrical body portion 5 centering on the can axis C is arranged in order from the bottom portion 2 toward the opening portion 4 on the upper end side of the can body 1, and gradually with a constant inclination toward the upper end side. A truncated conical shoulder portion 6 with a reduced diameter, a cylindrical neck portion 7 extending from the shoulder portion 6 toward the upper end, and a cap mounting portion 8 are formed. The cap mounting portion 8 has a male threaded portion 9 screwed into the female threaded portion of the cap that seals the can body 1 on the upper end side. It is provided with a bulging portion 10 which is swelled to a large extent and then reduced in diameter and wound around the open end portion of the lower end of the cap. The uppermost end of the cap attachment portion 8 is a curled portion 8a.

Here, the can height from the lower edge of the bottom portion 2 of the can body 1 (the lower edge of the annular convex portion 2b) to the upper edge of the outer peripheral portion 3 (the upper edge of the curled portion 8a) is for a content capacity of 310 ml. The can body 1 of the bottle-can is 131.6 mm to 133.6 mm, and the can body 1 of the bottle-can for the content capacity of 410 ml is 163.0 mm to 165.0 mm. Also, the diameter of the body portion 5 in the outer peripheral portion 3 of the can body 1 is both 64.24 mm to 68.24 mm.

In order to manufacture such bottle cans, first, in a cupping press step using a cupping press, a metal plate is punched into a disk shape and drawn to manufacture a shallow cup-shaped material. The metal plate formed into the cup-shaped material in this cupping press process has a base plate thickness of 0.260 mm to 0.310 mm for the can body 1 of the 310 ml bottle can, and a base plate thickness for the can body 1 of the 410 ml bottle can. An aluminum plate with a thickness of 0.310 mm to 0.365 mm or an aluminum alloy plate of A3004 or A3104 according to JIS H 4000, having a 0.2% proof stress of 235 N/mm ² to 265 N/mm after baking at 205°C for 20 minutes. A range of ² is used, for example.

Next, the cup-shaped material is subjected to redrawing and ironing in a DI press process using a DI press machine, and then stretched in the direction of the can axis C to form a cylindrical portion around the can axis C on the outer peripheral portion. At the same time, a bottomed cylindrical body having a dome portion 2a and an annular convex portion 2b similar to those of the can body 1 is formed at the bottom. The thickness of the bottomed cylindrical body and the bottom portion 2 of the can body 1 is substantially equal to the original plate thickness of the metal plate formed into the cup-shaped material in the cupping press process.

The cylindrical portion of the bottomed cylindrical body has a constant outer diameter (diameter) substantially equal to the outer diameter of the body portion 5 of the can body 1 . Furthermore, the portion on the bottom side of the cylindrical portion is a wall portion, which is a thin portion with a reduced thickness (thickness), and the portion on the upper end side opposite to the bottom portion is thicker than the wall portion. It is considered as a flange portion which is a thickened thick portion. Here, in order to form the wall portion and the flange portion having different thicknesses in the cylindrical portion, the outer surface of the punch which is subjected to ironing with a plurality of ironing dies in the DI press machine as described above must be A recess having a depth that takes account of the difference in thickness may be formed at a position corresponding to the flange.

In such a bottomed cylindrical body, the thickness of the thinnest portion of the wall portion of the cylindrical portion is in the range of 0.100 mm to 0.130 mm, and the thickest portion of the cylindrical portion is the flange. The thickness of the portion is 0.160 mm to 0.210 mm. Furthermore, the step between the flange portion and the thinnest portion of the wall portion is 0.090 mm or less, preferably 0.070 mm or less, but preferably 0.045 mm or more. .

In the trimming step using a trimmer, the cylindrical body with a bottom formed in this way is trimmed at the upper end edge of the cylindrical portion with a predetermined trim margin to align the height, and then washed and dried in the first washing step. Next, in the painting process, the inner and outer surfaces are painted and baked. Further, in the bottleneck molding process using a bottle necker, the diameter of the flange portion of the cylindrical portion of the painted bottomed cylindrical body is reduced, and the shoulder portion 6 and the neck portion 7 are formed.

Next, the upper end side of the neck portion 7 is enlarged to form the bulging portion 10, and the male screw portion 9 is formed on the upper end side of the bulging portion 10 by threading. The cap mounting portion 8 is formed by folding the upper end portion to the outer peripheral side, curling it, and then crushing it by throttle processing to form the curled portion 8a.

Here, the male screw portion 9 is twisted toward the lower end side as it goes clockwise in plan view from the side of the curl portion 8a, and the screw thread gradually protrudes to the outer peripheral side at the incomplete screw portion. The left and right slopes of the crest form a complete screw portion that effectively functions as a symmetrical screw. Further, the male threaded portion 9 gradually retracts toward the inner peripheral side when the screw thread has made one or more effective screw turns (2.2 turns in this embodiment) in the complete threaded portion, and again the incompletely threaded portion. becomes. The screw height from the bottom of the screw root to the top of the screw thread in the fully threaded portion of the male screw portion 9 is, for example, the screw height from the screw root portion of the screw thread with the largest outer diameter in the male screw portion 9. 50% or more.

In the first reference example, the bulging portion 10 has an enlarged diameter portion 10a on the upper end side that bulges toward the outer peripheral side as it goes downward while drawing a convex curve in a cross section along the can axis C, and On the side thereof, there is provided a diameter-reduced portion 10b which has a convex curve shape in cross section smoothly connecting to the convex curve formed by the cross-section of the diameter-enlarged portion 10a and whose diameter decreases downward. The convex curve formed by the section of the reduced diameter portion 10b has a smaller radius of curvature than the convex curve formed by the enlarged diameter portion 10a, and the open end of the cap is wound around the reduced diameter portion 10b. In contrast to such a first reference example, in one embodiment of the present invention, the enlarged diameter portion 10a swells toward the outer peripheral side as it extends linearly downward in a cross section along the can axis C , The inclination angle with respect to the can axis C is 3° to 30°, more preferably 5° to 15°. With such an angle range, the buckling strength of the bulging portion 10 is further improved. The diameter-reduced portion 10b also linearly decreases in diameter downward in a cross section along the can axis C , and the inclination angle thereof with respect to the can axis C is set to 40° to 50°. Such an angular range is suitable for skirting the open end of the cap. The thickness t of the bulging portion 10 in the radial direction with respect to the can axis C at the boundary between the enlarged diameter portion 10a and the reduced diameter portion 10b of the bulging portion 10, that is, the position of the maximum outer diameter of the bulging portion 10 is In the case of a bottle-shaped can formed from a metal plate having a reduced original thickness as described above, the thickness is in the range of 0.165 mm to 0.220 mm.

In the bottle can having the above structure, in the cap attachment portion 8 of the can body 1 formed in this manner, the bulging portion 10 has the same cross section along the can axis C over the entire circumference around the can axis C. , and is separated in the direction of the male screw portion 9 and the can axis C. That is, the terminal end (lower end) of the male threaded portion 9 does not reach the bulging portion 10, and in this embodiment, as shown in FIG. 10 is spaced in the can axis C direction from the enlarged diameter portion 10a.

In the bottle-can constructed in this manner, the male screw portion 9 of the cap attachment portion 8 is separated from the bulging portion 10 in the direction of the can axis C without reaching the bulging portion 10, and the bulging portion 10 is separated from the can axis C direction. Since the cross section along the axis C is the same over the entire circumference around the can axis C, the length of the enlarged diameter portion 10a that bulges downward from the bulging portion 10 in the direction of the can axis C also extends over the entire circumference. In addition, the angle of inclination of the enlarged diameter portion 10a with respect to the can axis C in the cross section along the can axis C is also constant. It can be made uniform all around the circumference of the axis C.

Therefore, it is possible to prevent local buckling of the cap mounting portion 8 due to the load of the drawing process during capping due to non-uniformity in the length, inclination angle, and buckling strength of the enlarged diameter portion 10a. To prevent deformation of the male screw portion 9 originating from such local buckling when the open end portion of the cap is pressed by a roller and wound around the reduced diameter portion 10b of the bulging portion 10. can be done. Therefore, even if the can body 1 of the bottle can is made thinner as described above, such deformation of the male screw portion 9 may cause a situation in which the once removed cap cannot be resealed, or the resealing torque may increase. can be prevented, and the cap can be reliably resealed.

Further, in the present embodiment, as described above, a space is provided in the can axis C direction between the screw thread and thread root at the terminal end of the male screw portion 9 and the enlarged diameter portion 10a of the bulging portion 10. Thus, it is possible to more reliably prevent the male screw portion 9 from reaching and biting into the bulging portion 10. - 特許庁However, in the reference example of the present invention , if the male screw portion 9 does not bite into the bulging portion 10 as described above, the screw thread and thread root at the terminal end of the male screw portion 9 and the enlarged diameter portion 10a of the bulging portion 10 may be in contact.

Next, FIGS. 3 and 4 show a second reference example for the embodiment of the present invention, and parts common to the first reference example shown in FIGS. 1 and 2 are assigned the same reference numerals. , and the explanation is omitted. In this second reference example, a concave portion 11 recessed toward the inner peripheral side of the cap mounting portion 8 is formed along the entire circumference of the can axis C between the male screw portion 9 and the bulging portion 10 of the cap mounting portion 8. It is characterized by being formed as follows.

The recessed portion 11 in this reference example begins to dent inward while drawing a concave curve in a cross section along the can axis C from a position slightly spaced downward from the terminal end of the male screw portion 9 in the direction of the can axis C. , and after passing through the most recessed position, it rises to the outer peripheral side and intersects the enlarged diameter portion 10a of the bulging portion 10. - 特許庁The radius of curvature of the concave curve formed by the recess 11 in the cross section along the can axis C is made larger than the radius of curvature of the convex curve formed by the cross section of the enlarged diameter portion 10a in this reference example .

In the second reference example configured as described above, the male threaded portion 9 and the bulging portion 10 can be more reliably separated in the direction of the can axis C by the recess 11, and the male threaded portion 9 is separated from the bulging portion 10 by the can axis C direction. can be prevented from reaching and eating into Further, by forming the concave portion 11 which is recessed toward the inner peripheral side in this manner over the entire circumference, the buckling strength of the cap attachment portion 8 against the load in the direction of the can axis C can be further improved.

Further, FIGS. 5 and 6 show third and fourth reference examples for the embodiment of the present invention, respectively, which are common to the first and second reference examples shown in FIGS. 1 to 4. The same reference numerals are assigned to the parts, and the description thereof is omitted. In these third and fourth reference examples, the number of effective screw turns of the male screw portion 9 was 2.2 turns in the first and second reference examples, whereas the number of effective screw turns of the male screw portion 9 was 2.2. The number of turns is in the range of 1.0 turns to 1.7 turns (for example, 1.5 turns). The third reference example shown in FIG. 5 does not have the concave portion 11, and the fourth reference example shown in FIG.

In the third and fourth reference examples , since the number of effective screw turns is small, the length of the male screw portion 9 in the can axis C direction can be shortened. Therefore, the length of the cap attachment portion 8 and the length of the cap attached to the cap attachment portion 8 in the direction of the can axis C can be shortened. 10 can be divided in the can axis C direction, it is possible to surely promote weight reduction of bottle cans and bottle cans with caps.

REFERENCE SIGNS LIST 1 can body 2 bottom 3 outer periphery 4 opening 5 trunk 6 shoulder 7 neck 8 cap mounting portion 8a curl portion 9 male screw portion 10 bulging portion 10a expanded diameter portion 10b reduced diameter portion C can shaft

Claims (3)

A metal bottle can having a cylindrical cap attachment portion to which a cap is attached is formed at the upper end of a bottomed cylindrical can body centered on the can axis,
The cap mounting portion has a male threaded portion on the upper end side, and a bulging portion on the lower end side, which bulges to the outer peripheral side as it goes downward and then reduces in diameter so that the open end portion of the lower end of the cap is wound. prepared,
The bulging portion has the same cross section along the can axis over the entire circumference around the can axis, and is separated from the male screw portion in the can axis direction,
The bulging portion has an enlarged diameter portion on the upper end side that swells toward the outer peripheral side as it goes linearly downward in a cross section along the can axis, and has a linear shape on the lower end side in a cross section along the can axis. Equipped with a reduced diameter portion that decreases in diameter as it goes downward,
The inclination angle of the enlarged diameter portion with respect to the can axis is 3° to 30°, and the inclination angle of the diameter reduction portion with respect to the can axis is 40° to 50°,
The lower end of the male screw portion does not reach the bulging portion,
The length of the enlarged diameter portion in the can axis direction is uniform over the entire circumference around the can axis, and the enlarged diameter portion forms the can axis in a cross section along the can axis. A bottle can characterized in that the inclination angle is also constant over the entire periphery of the can axis . 2. The bottle can according to claim 1, wherein said enlarged diameter portion has an inclination angle of 5° to 15° with respect to said can axis. A thickness of the bulging portion in a radial direction with respect to the can axis of the bulging portion at a boundary between the enlarged diameter portion and the reduced diameter portion is in the range of 0.165 mm to 0.220 mm. The bottle can according to claim 1 or claim 2.

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