JP5271332B2 - Double winding structure of can - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure for double seaming part of a can which uses a thin can lid material, and has strength surely securing sealing performance. <P>SOLUTION: In the structure for double seaming part of a can, a can lid 20 formed with the usage of a lid material having a thickness of equal to or less than 0.230 mm is seamed around a can body 10. The can body 10 includes a barrel 11 of a bottomed cylindrical shape and a body hook 12; the can lid 20 includes a cover hook 21, a seaming wall 22, a seaming panel 23, a chuck wall 24, a counter sink 25, and a panel 26; a first curved part 24a and a second curved part 24b are formed in the halfway part of the chuck wall 24, and a radius of curvature R1 of an outer surface of a seaming wall radius 27 formed in a connection part of the seaming wall 22 and the seaming panel 23 of the can lid 20 is equal to or more than 0.48 mm and equal to or less than 0.67 mm, and a radius of curvature R2 of an inner peripheral surface of the first curved part 24a is equal to or more than 0.3 mm and equal to or less than 0.9 mm. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a double-clamping portion structure of a can obtained by double-wrapping an outer peripheral portion of a can lid at an opening end portion of a can body.

  Conventionally, as shown in Patent Document 1, a can filled with a soft drink or the like has a structure in which an outer peripheral portion of a can lid is double-rolled around an opening of a bottomed cylindrical can body. . Such a double tightening portion of the can has a flange portion formed in advance at the opening end portion of the can body, and a curl portion is formed in the outer peripheral portion of the can lid, and the can lid is formed on the flange portion of the can body. The curled part of the can lid is curled together on the outside, and the curled part of the can lid is wrapped around the flange of the can body while being folded back like a bowl, and the curled part is Further, the compound applied to the inner surface of the curl portion of the can lid can be deformed by pressing so as to be crushed from the outside in the radial direction, that is, by deforming the can lid and the can body so as to be wound in a state where they overlap each other. It is made into the structure sealed by interposing in a compression state between a trunk | drum and a can lid.

  When filling effervescent beverages such as beer and carbonated beverages as contents, or when non-effervescent beverages such as tea and coffee are filled with liquid nitrogen during filling, so-called positive pressure is applied after sealing. The pressure can is required to have a strength that can withstand the internal pressure. For example, in order to increase the pressure resistance of the can lid, various proposals have been made such as reducing the width of the counter sink or devising the shape of the chuck wall.

Japanese Patent Laid-Open No. 61-140337

  In order to reduce the material cost, it is required to reduce the thickness of the can lid. However, when the can lid material is thinned, it becomes easy to cause a winding failure called drooping that makes it difficult to entrain the can body, or the can lid tends to lift and the can shaft between the can body and the can lid There is a possibility that the gap along the direction (the seam gap) becomes large and the sealing performance is lowered.

  The present invention has been made in view of such circumstances, and provides a double-clamped portion structure of a can having a strength capable of reliably ensuring sealing performance by using a thin can lid material. Objective.

  The present invention is a double winding structure of a can formed by winding a can lid formed using a lid material having a plate thickness of 0.230 mm or less around the can body, and the can body has a bottomed cylindrical shape. A body portion, and a substantially cylindrical body hook that is folded outward from the upper end of the body portion and extends downward, and the can lid is formed between the body hook and the body portion from below. A substantially cylindrical cover hook provided so as to enter, and a substantially cylindrical seaming wall provided to cover the outer periphery of the body hook, which is folded back from the lower end of the cover hook to the outer peripheral side and extends upward. A seaming panel that is folded back from the upper end of the seaming wall to the inner peripheral side, and a substantially cylinder that extends downward from the inner peripheral end of the seaming panel and covers the inner periphery of the body portion Shaped chuck wall An annular groove-shaped counter sink provided continuously to the lower portion of the chuck wall, and a disk-shaped panel provided on the inner peripheral side of the counter sink, A first curved portion projecting outward in the radial direction and a second curved portion projecting inward in the radial direction are formed below the first curved portion, and the seaming A radius of curvature of an outer surface of a seaming wall radius formed at a connection portion between the panel and the seaming wall and projecting radially outward is 0.48 mm or more and 0.67 mm or less, and the first The curvature radius of the inner peripheral surface of the curved portion is 0.3 mm or more and 0.9 mm or less.

  According to the double tightening portion structure of the present invention, since the radius of curvature on the inner surface of the first bending portion is set to 0.3 mm or more, the strength can be reduced by suppressing a significant decrease in the plate thickness due to deformation due to winding. It is possible to prevent the occurrence of cracks during buckling when the panel bulges outward. Further, since the radius of curvature on the inner surface of the first curved portion is set to 0.9 mm or less and the radius of curvature on the outer surface of the seaming wall radius is set to 0.48 mm or more, the deformation of the tightening portion due to internal pressure is suppressed, and the seam It is possible to prevent the sealing performance from being lowered due to the widening of the gap. On the other hand, if the radius of curvature of the outer surface of the seaming wall radius exceeds 0.67 mm, drooping may occur in the winding process, so that it is set to 0.67 mm or less in the present invention.

  The radius of curvature, such as the first curved part and seaming wall radius, in the double-clamping structure of this can, in the longitudinal section along the can axis direction, considers the arc whose dimension is to be obtained as a single arc, and within an appropriate range. Calculated from three arc-shaped points.

  According to the double tightening portion structure of the can of the present invention, even when a can lid made of a thin lid material having a plate thickness of 0.230 mm or less is used, sufficient strength and hermeticity can be maintained. Can provide.

It is an expanded longitudinal cross-sectional view which shows the double winding structure of the can which concerns on this invention. It is the elements on larger scale of the double winding structure shown in FIG. It is the elements on larger scale which show the 1st winding process in a double winding process. It is a partial enlarged view which shows the 2nd winding process in a double winding process.

  Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the present invention is a double winding structure of a can formed by winding a can lid 20 formed using a lid material having a plate thickness of 0.230 mm or less with respect to a can body 10. .

  The can body 10 has a bottomed cylindrical body portion 11 and a substantially cylindrical body hook 12 that is folded back from the upper end of the body portion 11 to the outer peripheral side and extends downward.

  The can lid 20 has a substantially cylindrical cover hook 21 provided so as to be inserted between the body hook 12 and the body portion 11 from below, and is folded from the lower end of the cover hook 21 to the outer peripheral side and directed upward. A substantially cylindrical seaming wall 22 provided so as to cover the outer periphery of the extending body hook 12, a seaming panel 23 folded back from the upper end of the seaming wall 22 to the inner peripheral side, and the seaming panel 23 A substantially cylindrical chuck wall 24 that extends downward from the inner peripheral end and covers the inner periphery of the body 11, and an annular groove-shaped counter sink 25 that is provided continuously to the lower portion of the chuck wall 24. And a disk-shaped panel 26 provided on the inner peripheral side of the counter sink 25.

  In the can lid 20, a first curved portion 24 a that protrudes outward in the radial direction is formed in the middle portion of the chuck wall 24, and the first curved portion 24 a extends downward in the radial direction. A certain second bending portion 24b is formed. The seaming wall 22 and the chuck wall 24 are connected by a seaming panel 23. A seaming wall radius 27 having a substantially arc-shaped cross section that protrudes outward in the radial direction is formed at a connection portion between the seaming panel 23 and the seaming wall 22. The radius of curvature R1 of the outer surface of the seaming wall radius 27 is not less than 0.48 mm and not more than 0.67 mm. Further, the radius of curvature R2 of the inner peripheral surface of the first curved portion 24a is not less than 0.3 mm and not more than 0.9 mm.

  Note that the radius of curvature of the first curved portion 24a, the second curved portion 24b, the seaming wall radius 27, etc. is considered to be an appropriate range in the longitudinal section along the can axis direction, assuming that the arc whose dimension is to be obtained is a single arc. Calculated from three arc-shaped points.

  As shown in FIG. 1 and FIG. 2, the sealing performance is secured between the can body 10 and the can lid 20 by bending a compound (seaming compound) C in a compressed state. . However, when the internal pressure of the container indicated by the arrow in FIG. 1 rises and the can lid 20 is lifted with respect to the can body 10, the sealing performance may be impaired. That is, when the can lid 20 is lifted by the internal pressure and the seam gap G is enlarged, the sealing performance of the container may be impaired.

  In contrast, in the double tightening portion structure of the present embodiment, the first bending portion 24 a and the second bending portion 24 b are continuously formed in the middle portion of the chuck wall 24 of the can lid 20. The center of curvature of the first curved portion 24a is on the inner peripheral side (can lid center side from the first curved portion 24a), and the center of curvature of the second curved portion 24b is on the outer peripheral side (outside of the can lid 20 from the second curved portion 24b). Therefore, when the internal pressure of the container rises and a force to lift the panel 26 as shown by the arrow in FIG. 1 is generated, the first bending portion 24a and the second bending portion 24b are two points in FIG. The panel 26 is displaced by being deformed as indicated by a chain line. Therefore, the deformation of the seaming panel 23 and the expansion of the seam gap G can be prevented, and the displacement of the panel 26 in the can lid 20 can be allowed, thereby maintaining the sealing performance.

  In the can lid 20, if the radius of curvature of the first curved portion 24a is too small, the plate thickness is remarkably reduced during molding, and buckling may easily occur. On the other hand, in the double tightening portion structure of the present embodiment, the curvature radius R2 of the inner peripheral surface of the first curved portion 24a is 0.3 mm or more, so that the plate thickness may be significantly reduced during molding. Therefore, the occurrence of buckling can be prevented.

  On the other hand, if the radius of curvature of the first curved portion 24a is too large, the first curved portion 24a is not easily deformed when a force for lifting the panel 26 is generated, and the entire can lid 20 is lifted with respect to the can body 10, and the seam gap G expands. On the other hand, in the double tightening portion structure of the present embodiment, the first bending portion 24a is appropriately deformed by the curvature radius R2 of the inner peripheral surface of the first bending portion 24a being 0.9 mm or less. Since it is easy, the expansion of the seam gap G can be prevented.

  Further, in the can lid 20, the curvature radius R1 of the outer surface of the seaming wall radius 27 is set to 0.48 mm or more and 0.67 mm or less. If the radius of curvature R1 of the outer surface of the seaming wall radius 27 is too small, the volume of the gap formed between the can body 10 and the can lid 20 becomes large, and the compression of the compound C becomes insufficient. There is a possibility that the sealing performance is lowered. Furthermore, in this case, if a force that lifts the panel 26 due to an increase in internal pressure is applied, the sealing performance between the can body 10 and the can lid 20 may be easily lost. On the other hand, in the double tightening portion structure of this embodiment, since the radius of curvature R1 of the outer surface of the seaming wall radius 27 is 0.48 mm or more, the sealing performance of this portion can be sufficiently maintained. .

  On the other hand, if the curvature radius R1 of the outer surface of the seaming wall radius 27 is too large, a part of the cover member protrudes from the groove shape of the second seaming roll 52 (see FIG. 4), and the tightening width (double winding tightening) Drooping in which the dimension of the portion in the height direction) is apparently increased is likely to occur. On the other hand, in the double tightening structure of the present embodiment, since the radius of curvature R1 of the outer surface of the seaming wall radius 27 is 0.67 mm or less, the occurrence of drooping can be prevented.

  Here, the double winding method of a can is demonstrated. The can body 30 before being double-rolled is formed by punching an aluminum alloy plate material having a base plate thickness of 0.230 mm to 0.340 mm into a wide-mouthed cup shape, and then drawing and ironing (DI processing). By slightly reducing the diameter of the open end portion of the straight bottomed cylindrical body portion 31 and then increasing the diameter, a flange portion 32 that extends radially outward from the upper end of the body portion 31 is formed (FIG. 3). ).

  The can lid 40 before being double-rolled is formed by press-molding an aluminum alloy lid material having a base plate thickness of 0.230 mm or less, for example, 0.200 mm to 0.230 mm, so that the body portion 31 of the can body 30 can be obtained. A circular panel 41 having a smaller diameter is formed at the center. A chuck wall 43 is formed on the outer edge of the panel 41 so as to extend upward through a counter sink 42 that forms an annular groove. From the upper end of the chuck wall 43, a curled portion 44 is formed that extends outward in the radial direction and has an outer peripheral edge curled outward. Compound C is applied to the inner surface of the curled portion 44 (FIG. 3).

  In the double tightening step, as shown in FIG. 3, first, the curl portion 44 of the can lid 40 is placed on the flange portion 32 of the can body 30 placed on a lifter (not shown), and the chuck 50 is placed from above. In a state where the can body 30 and the can lid 40 are sandwiched along the can axis direction between the chuck 50 and the lifter while being fitted to the lid 40, the first seaming roll 51 is moved from the outside in the radial direction. The curled portion 44 of the can lid 40 and the flange portion 32 of the can body 30 are integrally curled outward, and the curled portion 44 of the can lid 40 is folded back from the outside of the flange portion 32 of the can body 30 in a bowl shape. While embracing while wrapping (first winding process).

  Next, as shown in FIG. 4, the second seaming roll 52 is approached from the outside in the radial direction to the winding portion, and the winding portion is further pressed from the outside in the radial direction (second winding tightening). Process). Thereby, the double winding part which made the compound C interpose in a compression state between the can body 30 and the can lid 40 is formed (FIG. 2).

Next, examples of the present invention will be described in comparison with comparative examples.
An aluminum alloy having a base plate thickness of 0.270 mm was formed as the can body, and an aluminum alloy having a base plate thickness of 0.220 mm was formed as the can lid. The can body was filled with a content liquid having a gas volume of 3.0, and the can lid was wound to prepare a beverage can. At that time, the shape and pressing force of the seaming roll of the tightening device are changed so that the radius of curvature R1 of the outer surface of the seaming wall radius 27 and the radius of curvature R2 of the inner peripheral surface of the first curved portion 24a are different. A plurality of cans were produced.

  The winding width of the can (the length of the double winding portion in the can axis direction) was W = 2.55 mm, and the winding thickness (the thickness of the double winding portion) was T = 1.20 mm (see FIG. 2).

  The dimensions of each part are as follows: after allowing a beverage can filled with the content liquid of gas volume 3.0 to stand for more than one week, the can body is cut and the content liquid is discharged; It cut | disconnected so that it might pass through the center of the rivet of a can lid, and after grind | polishing the cross section, it expanded and measured with the microscope. In the measurement, in each cross section, an arc whose dimension was to be obtained was regarded as a single arc, and calculation was performed from three arc-shaped points determined within an appropriate range. Five cans were prepared for each sample, and two tightened portions 180 ° apart from one cross section were measured. Therefore, there are 10 measurement locations. Table 1 shows the average value of the measurement results at 10 locations.

  The seam gap G was determined to be NG when the measured value exceeded the thickness of the lid. Drooping was determined as NG when the tightening width W exceeded 1.2 times the set value.

  As can be seen from the results in Table 1, the radius of curvature R1 of the outer surface of the seaming wall radius 27 is 0.48 mm or 0.67 mm, and the radius of curvature R2 of the inner peripheral surface of the first curved portion 24a is 0.30 mm. In the case of 50 mm or 0.9 mm, there was no excessive expansion of the seam gap and drooping. That is, when the curvature radius R1 of the outer surface of the seaming wall radius 27 is 0.48 mm or more and 0.67 mm or less, and the curvature radius R2 of the inner peripheral surface of the first bending portion 24a is 0.30 mm or more and 0.9 mm or less. It was confirmed that the expansion of the seam gap and the occurrence of drooping, which caused a decrease in the sealing performance, were prevented.

  In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.

10 Can body 11 Body 12 Body hook 20 Can lid 21 Cover hook 22 Seaming wall 23 Seaming panel 24 Chuck wall 24a First curved portion 24b Second curved portion 25 Counter sink 26 Panel 27 Seaming wall radius C compound (see Mining compound)
G Seam gap

Claims (1)

A double winding structure of a can formed by winding a can lid formed using a lid material having a plate thickness of 0.230 mm or less around a can body,
The can body has a cylindrical body portion with a bottom and a substantially cylindrical body hook that is folded from the upper end of the body portion toward the outer periphery and extends downward.
The can lid has a substantially cylindrical cover hook provided so as to enter from between the body hook and the body portion from below, and is folded back from the lower end of the cover hook to the outer peripheral side and extends upward. A substantially cylindrical seaming wall provided so as to cover the outer periphery of the body hook, a seaming panel folded back from the upper end of the seaming wall to the inner peripheral side, and downward from the inner peripheral end of the seaming panel A substantially cylindrical chuck wall provided extending so as to cover the inner periphery of the body portion, an annular groove-shaped counter sink provided continuously to the lower portion of the chuck wall, and an inner peripheral side of the counter sink A disk-shaped panel provided in
In the middle of the chuck wall, there are a first curved portion that is convex outward in the radial direction, and a second curved portion that is continuous below the first curved portion and is convex inward in the radial direction. Formed,
The radius of curvature of the outer surface of the seaming wall radius formed at the connection portion between the seaming panel and the seaming wall and convex outward in the radial direction is 0.48 mm to 0.67 mm, and The double winding part structure of a can, wherein a radius of curvature of an inner peripheral surface of the first curved part is 0.3 mm or more and 0.9 mm or less.

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