JP2018162071A - Bottle can - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bottle can which can secure buckling strength in a can axial direction of a cap fitting part even in a thinned bottle can, and which can prevent that resealing torque increases and which can prevent that resealing cannot be executed.SOLUTION: A metal bottle can has a cylindrical cap fitting part 8, to which a cap is mounted, formed at an upper end part of a bottomed cylindrical can main body 1 with a can axis C as a center. The cap fitting part 8 includes: at an upper end side, a male screw part 9 which is screwed in a female screw part of the cap; and at a lower end side, a swollen part 10 in which after the swollen part is swelled toward an outer peripheral side as it goes downward, a diameter of the swollen part is contracted, so an open end part of a lower end of the cap is rolled and pressed. The swollen part 10 has the same cross section along the can axis C over the entire circumference around the can axis C, and is separated from the male screw part 9 in a can axis C direction.SELECTED DRAWING: Figure 1

Description

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

  As such a bottle can, for example, in Patent Document 1, a cylindrical body portion, a shoulder portion which is inclined with respect to the can shaft and has a diameter reduced upward, at the upper portion of the body portion, and the shoulder portion A cylindrical mouth portion (cap attaching portion) extending upward, the mouth portion including a base portion connected to an upper end of a shoulder portion, a skirt valley portion connected to the base portion, and the skirt A metal part such as aluminum having a skirt part (bulged part) connected to the valley part and a screw part (male thread part) connected to the skirt part is described. Here, in FIG. 1 of this patent document 1, the termination | terminus (lower end) of the external thread part has reached even the bulging part in the can axial direction.

  In such a bottle can, after the beverage is filled inside, the cap mounting portion is similarly covered with a metal cap such as aluminum, and the cap is drawn by applying a load in the can axis direction by the block. The threaded roller applies a load to the cap on the inner peripheral side in the direction perpendicular to the can axis, thereby forming a female threaded part to follow the male threaded part, and the skirt roller further opens the lower end of the cap. By being pressed toward the inner peripheral side, it is wound and sealed around the reduced diameter portion below the bulging portion.

JP 2006-196332 A

  By the way, in recent years, such bottle cans have been required to reduce the weight of the can body in order to save resources of the metal material forming the can body and save energy when manufacturing the material. Even if it can only be made into a bottle, a huge number of bottle cans distributed in the market can achieve significant resource and energy savings or cost reduction of the can body. Here, in order to reduce the weight of such a can body, it is conceivable to reduce the thickness of the body portion, the shoulder portion, and the cap attachment portion by reducing the original plate thickness of the metal plate formed on the can body. .

  However, in such a thinned bottle can, as described in Patent Document 1, when the end of the male screw portion reaches the bulging portion, the bulging portion expands downward. The length of the can axis direction is uneven in the circumferential direction, the enlarged diameter portion is shortened near the end of the male screw portion, and the cross section along the can axis of the enlarged diameter portion is inclined with respect to the can axis. Since the angle becomes large, the buckling strength in the can axis direction cannot be secured, and 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 is the starting point and resists the pressing force when the open end of the cap is wound around the reduced diameter portion of the bulge by the skirt roller. The male screw part is deformed without being completely closed. When the male screw portion is deformed in this way, the rotational torque (reseal torque) when the cap is once removed from the cap mounting portion and then screwed into the male screw portion is increased, or in some cases, the cap is attached. May not be able to be resealed.

  The present invention has been made under such a background. Even in a thin bottle can, the buckling strength in the can axis direction of the cap mounting portion can be secured, and the reseal torque is increased. It is an object of the present invention to provide a bottle can that can prevent re-sealing.

  In order to solve the above-described problems and achieve such an object, the present invention provides a cylindrical cap attachment portion to which a cap is attached to an upper end portion of a bottomed cylindrical can body centering on a can shaft. In the formed metal bottle can, the cap mounting portion includes a male screw portion screwed into the female screw portion of the cap on the upper end side, and bulges toward the outer peripheral side toward the lower side on the lower end side. The bulging portion is provided with a bulging portion that is later reduced in diameter and wound with the open end portion of the lower end of the cap, and the bulging portion has the same cross section along the can axis over the entire circumference of the can axis. The male screw part and the can axis direction are divided.

  In the bottle can configured in this way, the male threaded portion of the cap mounting portion is divided into the bulging portion and the can axis direction without reaching the bulging portion, and the bulging portion is a cross section along the can axis Is the same over the entire circumference of the can axis, and the length of the enlarged diameter portion expanding toward the lower side of the bulging portion is uniform, and the enlarged diameter portion in a cross section along the can axis The inclination angle made by the can axis is constant. For this reason, the buckling strength of the bulging portion in the can axis direction can be made uniform over the entire circumference around the can axis, and the local buckling strength can be applied to the cap mounting portion by the drawing load during capping. It is possible to prevent bending.

  Therefore, when the skirt roller is pressed and the open end of the cap is wound around the reduced diameter portion of the bulging portion, it is possible to prevent deformation of the male screw portion starting from such local buckling. Can do. For this reason, it is possible to prevent the resealing torque from being increased as well as to prevent the cap once resealed from being deformed due to the deformation of the male screw part, thereby impairing the resealability. It is possible to reduce the thickness of the bottle can without fail.

  Further, by forming a concave portion recessed on the inner peripheral side of the cap mounting portion between the bulging portion and the male screw portion over the entire circumference around the can shaft, the male screw portion and the bulging portion are formed. It is possible to further reliably divide the portion in the can axis direction and prevent the male screw portion from reaching the bulging portion, and to further improve the buckling strength of the cap mounting portion in the can axis direction.

  If the male screw part and the bulging part are divided in the can axis direction in this way, the length of the cap attaching part in the can axis direction becomes longer, and accordingly the length of the cap also becomes longer. There is a possibility that the weight reduction as a can or a bottle can with a cap may be impaired. Therefore, in such a case, the number of turns of the male screw portion in the range of 1.0 to 1.7 turns of the effective screw winding is reduced, and the length of the male screw portion in the can axis direction is shortened. That's fine.

  As described above, according to the present invention, even when the bottle can is thinned, it is possible to prevent local buckling from occurring in the cap mounting portion during capping, and to prevent the open end portion of the cap. It is possible to prevent the male screw portion from being deformed by winding and prevent the reseal torque of the cap from increasing or the cap from becoming unable to be resealed.

It is a side view which shows the 1st Embodiment of this invention. It is sectional drawing of the cap attaching part of embodiment shown in FIG. It is a side view which shows the cap attachment part of the 2nd Embodiment of this invention. It is sectional drawing of the cap attaching part of embodiment shown in FIG. It is a partially broken side view which shows the 3rd Embodiment of this invention. It is a side view which shows the cap attachment part of the 4th Embodiment of this invention.

  1 and 2 show a first embodiment of the present invention. In the bottle can of this embodiment, the can body 1 includes a bottom portion 2 and an outer peripheral portion 3 that is formed integrally with the bottom portion 2 and extends from the outer peripheral edge of the bottom portion 2 to the upper end side (the upper side in FIGS. 1 and 2). A substantially multi-stage bottomed cylindrical shape centering on a can axis C provided with A dome portion 2a having a substantially arc-shaped cross section that is recessed inwardly in the can axis C direction (upper end side of the can body 1) is formed in the bottom portion 2 at the center. An annular convex portion 2b projecting outward (the lower end side of the can body 1) is formed continuously in the circumferential direction around the can axis C (see FIG. 5).

  In addition, the outer peripheral portion 3 has a cylindrical body portion 5 centering on the can shaft C in order from the bottom portion 2 to 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 cone-shaped shoulder portion 6 having a reduced diameter, a cylindrical neck portion 7 extending from the shoulder portion 6 toward the upper end side, and a cap mounting portion 8 are formed. The cap mounting portion 8 includes a male screw portion 9 to be screwed into a female screw portion of a cap that seals the can main body 1 on the upper end side, and a lower outer peripheral side toward the lower end side than the male screw portion 9. And a bulging portion 10 which is reduced in diameter after being swelled and the open end portion of the lower end of the cap is tightened. The uppermost end portion of the cap attaching portion 8 is a curled portion 8a.

  Here, the can height from the lower end edge of the bottom part 2 of the can body 1 (the lower end edge of the annular convex part 2b) to the upper end of the outer peripheral part 3 (the upper end edge of the curled part 8a) is such that the content volume is 310 ml. In the can body 1 of the bottle can, 131.6 mm to 133.6 mm, and in the can body 1 of the bottle can for the content of 410 ml, the size is 163.0 mm to 165.0 mm. Moreover, the diameter of the trunk | drum 5 in the outer peripheral part 3 of the can main body 1 shall be 64.24 mm-68.24 mm.

In order to manufacture such a bottle can, first, in a cupping press process by a cupping press machine, a metal plate having a shallow depth is manufactured by punching a metal plate into a disk shape and performing a drawing process. The metal plate formed into a cup-shaped material in this cupping press process has a base plate thickness of 0.260 mm to 0.310 mm in the can body 1 of the bottle can for 310 ml, and a base plate in the can body 1 of the bottle can for 410 ml. An aluminum plate having a thickness of 0.310 mm to 0.365 mm or an aluminum alloy plate of A3004 or A3104 in JIS H4000, and 0.2% proof stress after baking at 205 ° C. for 20 minutes is 235 N / mm ^{2 to} 265 N / mm Those in the range of ² are used, for example.

  Next, the cup-shaped material is subjected to redrawing and ironing in a DI pressing process by a DI press machine and stretched in the direction of the can axis C, thereby forming a cylindrical portion around the can axis C on the outer periphery. In addition, 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 on the bottom portion. The thickness of the bottomed cylindrical body and the bottom 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 that is substantially equal to the outer diameter of the body portion 5 of the can body 1. Further, the bottom portion of the cylindrical portion is a wall portion which is a thin portion with a reduced thickness (thickness), and the upper end portion opposite to the bottom portion is thicker than the wall portion. The flange portion is a thickened thick portion. Here, in order to form the wall portion and the flange portion having different thicknesses in the cylindrical portion, as described above, the outer surface of the punch that performs the ironing process between a plurality of ironing dies in the DI press machine is used. A recess having a depth that takes into account the difference in thickness may be formed at a position corresponding to the flange portion.

  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 flange that is the thickest of the cylindrical portion The thickness of the part is 0.160 mm to 0.210 mm. Further, the step between the flange portion and the thinnest portion of the wall portion is set to 0.090 mm or less, preferably 0.070 mm or less, but preferably 0.045 mm or more. .

  The bottomed cylindrical body formed in this manner is cleaned and dried in the first cleaning step after the upper edge of the cylindrical portion is cut at a predetermined trim margin in the trimming step by the trimmer and the height is aligned. Next, in the painting process, the inner and outer surfaces are painted and baked. Further, the bottomed cylindrical body to which the coating has been applied, in the bottle neck forming process by the bottle necker, the diameter of the flange portion of the cylindrical portion 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 expanded to form the bulging portion 10, and the male screw portion 9 is formed by threading on the upper end side of the bulging portion 10. Further, the upper end side portion is folded and curled to the outer peripheral side, and then crushed by throttle processing to form the curled portion 8a, whereby the cap attaching portion 8 is formed.

  Here, the male screw portion 9 is gradually twisted toward the lower end side in the clockwise direction in plan view from the curled portion 8a side, and the thread gradually protrudes to the outer peripheral side at the incomplete screw portion, and the screw thread portion at the screw start portion. The left and right slopes of the mountain are complete screw parts that function effectively as symmetrical screws. Further, the male screw portion 9 gradually retreats to the inner peripheral side when the thread turns around the effective screw winding number of one or more turns (2.2 turns in this embodiment) in this complete screw portion, and again the incomplete screw portion. It becomes. The screw height from the bottom of the screw valley to the top of the screw thread in the complete screw part of the male screw part 9 is, for example, the screw height from the screw valley of the screw thread having the largest outer diameter in the male screw part 9. 50% or more.

  Further, the bulging portion 10 is provided with a large-diameter portion 10a that bulges toward the outer peripheral side toward the lower side while drawing a convex curve in a cross section along the can axis C, and has a large-diameter portion 10a on the lower end side. A diameter-reduced portion 10b is provided which has a convex cross-sectional shape that is smoothly connected to a convex curve formed by the cross section of the cross section and decreases in diameter toward the lower side. The convex curve formed by the cross 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. However, the enlarged diameter portion 10a may swell to the outer peripheral side linearly downward in the cross section along the can axis C, and the inclination angle with respect to the can axis C is preferably 3 ° to 30 °, preferably 5 °. ~ 15 ° is more preferred. In such an angle range, the buckling strength of the bulging portion 10 is further improved. Moreover, the diameter-reduced part 10b may also be diameter-reduced as it goes down linearly in the cross section along the can axis C, and the inclination angle with respect to the can axis C is preferably 40 ° to 50 °. Such an angle range is suitable for skirting the open end of the cap. The radial thickness t of the bulging portion 10 with respect to the can axis C at the boundary between the enlarged diameter portion 10a and the reduced diameter portion 10b in the bulging portion 10, that is, the position of the maximum outer diameter of the bulging portion 10 is In a bottle can formed from a metal plate whose original plate thickness is reduced as described above, the range is 0.165 mm to 0.220 mm.

  And in the bottle can of the said structure, in the said cap attachment part 8 of the can main body 1 shape | molded in this way, the cross section along the can axis | shaft C of the bulging part 10 is the same over the perimeter around the can axis | shaft C. Thus, it is divided into the male screw portion 9 and the can axis C direction. That is, the terminal end (lower end) of the male screw portion 9 does not reach the bulging portion 10, and in the present embodiment, as shown in FIG. A space is provided in the direction of the can axis C between the ten enlarged diameter portions 10a.

  In the bottle can configured as described above, the male screw portion 9 of the cap mounting portion 8 is divided into the bulging portion 10 and the can axis C direction without reaching the bulging portion 10, and the bulging portion 10 is a can. Since the cross section along the axis C is the same over the entire circumference around the can axis C, the length in the direction of the can axis C of the enlarged diameter portion 10a that swells downward from the bulging portion 10 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 is constant in the cross section along the can axis C. Therefore, the buckling strength of the bulging portion 10 in the can axis C direction can be increased. It can be made uniform over the entire circumference around the axis C.

  For this reason, it is possible to prevent local buckling from occurring in the cap mounting portion 8 due to the drawing processing load at the time of capping due to the uneven length, inclination angle, and buckling strength of the enlarged diameter portion 10a. When the open end of the cap is wound around the reduced diameter portion 10b of the bulging portion 10 by pressing with a roller, deformation of the male threaded portion 9 is prevented from starting from such local buckling. Can do. Therefore, even if the can body 1 of the bottle can is thinned as described above, such a situation that the cap once removed due to the deformation of the male screw portion 9 cannot be resealed or the reseal torque is increased. The cap can be securely resealed.

  Moreover, in this embodiment, the space | interval is opened in the can axis | shaft C direction between the screw thread and screw trough in the terminal end of the external thread part 9, and the enlarged diameter part 10a of the bulging part 10, as mentioned above. Therefore, it is possible to prevent the male screw portion 9 from reaching the bulging portion 10 and biting in with more certainty. However, if the male screw portion 9 does not bite into the bulging portion 10 in this way, the screw thread and screw valley at the end of the male screw portion 9 may be in contact with the enlarged diameter portion 10 a of the bulging portion 10. .

  Next, FIGS. 3 and 4 show the second embodiment of the present invention, and the same reference numerals are assigned to the parts to be supplied with the first embodiment shown in FIGS. Description is omitted. In the second embodiment, a recess 11 that is recessed on the inner peripheral side of the cap mounting portion 8 is provided between the male screw portion 9 and the bulging portion 10 of the cap mounting portion 8 on the entire circumference around the can axis C. It is characterized by being formed.

  In this embodiment, the concave portion 11 starts to be recessed toward the inner peripheral side while drawing a concave curve in a cross section along the can axis C from a position slightly spaced from the end of the male screw portion 9 to the lower end side in the direction of the can axis C. After passing through the most recessed position, it cuts to the outer peripheral side and intersects with the enlarged diameter portion 10a of the bulging portion 10. In this embodiment, the radius of curvature of the concave curve formed by the concave portion 11 in the cross section along the can axis C is larger than the radius of curvature of the convex curve formed by the cross section of the enlarged diameter portion 10a.

  In the second embodiment configured as described above, the male screw portion 9 and the bulging portion 10 can be more reliably separated in the direction of the can axis C by the concave portion 11, and the male screw portion 9 becomes the bulging portion 10. Can be prevented from reaching into and biting in. In addition, by forming the recess 11 that is recessed toward the inner periphery over the entire periphery, the buckling strength of the cap mounting 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 embodiments of the present invention, respectively, which are the same as those supplied in the first embodiment shown in FIGS. The reference numerals are assigned and the description is omitted. In the third and fourth embodiments, the effective screw winding number of the male screw portion 9 in the first, second, and second embodiments is 2.2, whereas The number of effective screw windings of the screw portion 9 is in the range of 1.0 to 1.7 windings (for example, 1.5 windings). In the third embodiment shown in FIG. 5, there is no recess 11, and in the fourth embodiment shown in FIG. 6, the recess 11 is formed between the male screw portion 9 and the bulging portion 10.

  In such third and fourth embodiments, 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. Accordingly, the length of the cap attaching portion 8 and the cap attached to the cap attaching portion 8 in the direction of the can axis C can be shortened, so that the male screw portion 9 and the bulging portion are combined with the thinning of the can body 1. Even if 10 is divided in the direction of the can axis C, it is possible to surely promote weight reduction of the bottle can and the bottle can with the cap.

  Next, the effect of the present invention will be demonstrated with examples of the present invention. In this example, the base plate thickness is 0.365 mm as a bottle can with a capacity of 410 ml based on the first embodiment, and the thickness of the thinnest portion of the wall portion in the cylindrical portion is 0.120 mm. From the bottomed cylindrical body (DI can) having a flange portion thickness of 0.165 mm, 20 cans having a can height of 165.0 mm and a barrel portion having an outer diameter of 66.0 mm were molded. The number of effective screw windings of the bottle cans of these examples is 2.2, the length of the bulging portion 10 in the direction of the can axis C is 6.25 mm, and the same size and shape are taken around the can axis C. It was.

  In addition, as a comparative example for this embodiment, the male screw portion reaches the bulging portion with the same dimensions and shape as the embodiment except for the cap mounting portion, and the number of effective screw turns, and the bulging portion in the can axis direction 20 cans were formed by thinning a conventional bottle can having a maximum length of 6.25 mm and a minimum length of 3.3 mm. In the bottle can of this comparative example, the thread valley at the end of the male thread reaches the bulge, and the vicinity of the end of the thread is the shortest position in the can axis direction of the bulge. In addition, the thickness t in the radial direction with respect to the can shaft of the bulging portion at the position of the maximum outer diameter of the bulging portion in these examples and comparative examples was 0.170 mm on average.

  The bottle cans of these examples and comparative examples are drawn with a load of 1000 N in the direction of the can axis C and capped with a tip load of 130 N by a thread roller and a tip load of 100 N by a skirt roller in a direction perpendicular to the can axis C. After the cap was removed, the cap was once removed and screwed into the male threaded portion again, and the maximum resealing torque required when resealing by returning to 30 ° before the original position was measured.

  As a result, in the bottles of the comparative example, the reseal torque was 17N in 20 cans, but the reseal torque of 50.0N was required in one can, and the reseal torque of 80.0N in the other can. In the remaining one can, resealing itself was impossible due to deformation of the male screw portion. On the other hand, in the bottle cans of the examples based on the present invention, the reseal torque of all 20 cans was 0 N, and light reseal was possible.

DESCRIPTION OF SYMBOLS 1 Can main body 2 Bottom part 3 Outer peripheral part 4 Opening part 5 Trunk part 6 Shoulder part 7 Neck part 8 Cap attaching part 8a Curl part 9 Male thread part 10 Expansion part 10a Diameter expansion part 10b Diameter reduction part C Can axis

Claims (3)

A metal bottle can in which a cylindrical cap attachment portion to which a cap is attached is formed at the upper end portion of a bottomed cylindrical can body centering on a can axis,
The cap mounting portion includes a male screw portion that is screwed into the female screw portion of the cap on the upper end side, and is reduced in diameter after being bulged toward the outer peripheral side toward the lower end side, and is opened at the lower end of the cap. It has a bulging part where the part is wound,
The bottle can characterized in that the bulging portion has the same cross-section along the can axis over the entire circumference of the can axis and is divided in the male screw portion and the can axis direction.   2. A concave portion recessed on the inner peripheral side of the cap mounting portion is formed between the bulging portion and the male screw portion over the entire circumference around the can shaft. Bottle can described in.   The bottle can according to claim 1 or 2, wherein the male screw part has an effective screw winding number in a range of 1.0 to 1.7.

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