JP6817106B2 - Bottle type can - Google Patents

Description

The present invention relates to a bottle-shaped can made of a metal plate as a material, and more particularly to a bottle-shaped can that can be resealed by screw-fitting a cap to a cylindrical nose.

Conventionally, a metal plate such as an aluminum alloy is squeezed and ironed to form a cup-shaped or cylindrical intermediate body with a bottom, and the open end of the intermediate body is gradually reduced in diameter to form a cylindrical shape. A bottle-shaped can with the mouth of the aluminum is known. The tip of the mouth is wound outward to form a curl, and the mouth is threaded to form a male screw and a turnip. Roll-on capping is known as a method of attaching a cap to a bottle-shaped can of this type and sealing it. In roll-on capping, a cylindrical cap rough shape material having a top plate part that closes the curl part is put on the mouth part, the cap rough shape material is pressed against the curl part by a pressing pad, and the corner part is narrowed down by a pressure block. Adhere the inner liner to the curl part. In that state, the cylindrical part (skirt part) of the rough cap material is narrowed down along the male thread part of the mouth part with a screw forming roll to form a female thread part, and a pill provided at the lower end part of the cylindrical part. The fur proof band is wrapped around the underside of the skirt by a hem tightening roll.

In this way, the mouth of the bottle-shaped can has an axial pushing force (axial load or plugging force) during capping, a lateral force (lateral load) or compressive force due to each roll, and each. The torsional load due to the relative turning of the roll while forming it acts in combination. Therefore, a large stress acts on the base portion of the mouth portion (the boundary portion with the shoulder portion), and this portion is easily deformed. In particular, if the shoulder is curved or bulged in a dome shape or a convex curved surface, the angle of the tangent (tangent to the generatrix of the convex curved surface) at the upper part of the shoulder to which the mouth is connected (the can center axis of the tangent). Angle with respect to) becomes large. Therefore, the above-mentioned plugging force tends to cause deformation of the upper part of the shoulder portion, or the portion extending from the mouth portion to the shoulder portion tends to buckle. Such deformation (hereinafter, may be simply referred to as buckling) may be caused not only by the plugging force but also by the deformation of the portion connecting the mouth and shoulder. That is, the screw forming roll and the hem tightening roll press a part of the outer peripheral portion of the skirt portion and the mouth portion of the cap from the outside toward the center portion in the radial direction. Therefore, these loads are loads in the direction of crushing the mouth portion, and when the rigidity of the mouth portion is low with respect to the load, the mouth portion is deformed into an elliptical cross section. When such deformation extends from the mouth portion to the upper portion of the shoulder portion, the rigidity against the plugging force in the portion where the curvature in the circumferential direction around the central axis becomes small becomes low, and buckling easily occurs in that portion.

In order to increase the rigidity against buckling as described above, it is sufficient to increase the wall thickness of the mouth and shoulders, but it is difficult to increase the wall thickness due to the demand for cost reduction and weight reduction. Nowadays, it is actually desired to reduce the wall thickness without impairing the rigidity. In particular, in bottle-type cans manufactured in the same process as DI cans, the diameter of the opening end side of the cylindrical intermediate body with a bottom is gradually reduced to form the shoulder and mouth, so that the shoulder The wall thickness is thinner than the neck, and it is difficult to secure its rigidity.

Therefore, for example, in the bottle-shaped can described in Patent Document 1, the shoulder portion is formed by forming an annular concave portion and a convex portion centered on the central axis of the can in the upper portion (the portion on the mouth portion side) of the shoulder portion. The rigidity of the upper part is improved. Further, Patent Document 2 describes a configuration in which the lateral strength is improved by forming a bead portion protruding inward of the mouth portion in a bulging portion connected to the lower side of the skirt valley portion. In addition, Patent Document 2 also shows an example in which a straight portion is provided under the bead portion. However, Patent Document 2 does not describe the specific shape and dimensions of the straight portion, and the action / effect of providing the straight portion.

Japanese Patent No. 3561796 Japanese Unexamined Patent Publication No. 2016-196332

According to the configuration described in Patent Document 1, the rigidity of the upper part of the shoulder portion can be improved. However, in roll-on capping, the neck portion is deformed into an elliptical shape by a screw forming roll or a hem tightening roll, which may cause buckling, whereas the configuration described in Patent Document 1 Then, it is difficult to improve the rigidity of the nose to the so-called elliptical deformation, and even if the buckling strength of the upper part of the shoulder can be increased, it is still insufficient and there is room for improvement. Further, since the configuration described in Patent Document 1 is a configuration in which an annular convex portion and a concave portion are formed on the upper portion of the shoulder portion, the shape of the upper portion of the shoulder portion that is easily visible to the consumer is smooth as before. It has to be different from the shape, and there are inconveniences such as being forced to change the design of the bottle-shaped can or limiting the degree of freedom in design.

On the other hand, according to the description of Patent Document 2, it is possible to improve the strength against a lateral load by the roll and prevent local deformation. However, the bead portion is a portion in which a part of the bulging portion is recessed inward in a band shape, and its width (dimension in the central axis direction of the mouth portion) is smaller than the width of the bulging portion and also has a height. Since it is low, the rigidity against so-called elliptical deformation due to the roll is not necessarily high enough, and even if the rigidity against a lateral load is improved, there is still room for improvement in terms of improving the buckling strength.

The present invention has been made by paying attention to the above technical problems, and an object of the present invention is to provide a bottle-shaped can capable of improving buckling strength and therefore being able to be thinned or lightened. is there.

In the present invention, in order to achieve the above object, the body portion and the bottom portion are integrally formed, and a shoulder portion whose outer diameter becomes smaller toward the upper side is continuously formed on the upper portion of the body portion. A cylindrical nose is continuously formed on the upper part of the shoulder portion, and the nose portion has a male screw portion, a bulge portion continuously formed under the male screw portion, and the bulge. In a bottle-type can in which a cabra portion having a concave portion having an outer diameter smaller than that of the protruding portion is formed, the S-shaped bead portion and the outer diameter are constant between the cabra portion and the shoulder portion in order from the cabra portion side. The straight portion is formed, and the S-shaped bead portion is a convex bead portion that is continuously formed in the recess and has a larger outer diameter than the recess, and a neck portion that is continuously below the convex bead portion. The straight portion has a concave bead portion that is formed so as to be recessed inside and whose cross-sectional shape is symmetrical to the cross-sectional shape of the convex bead portion, and the straight portion is continuous with the lower side of the concave bead portion. It is a bottle-shaped can characterized in that the length of the mouth portion in the central axial direction is formed between the portion and the shoulder portion with a length of 1 mm or more and 7 mm or less.

In the present invention, the straight portion has an outer diameter of 26 mm or more and 40 mm or less, and a thickness of 0.28 mm or more and 0.34 mm or less.

Further, in the present invention, the outer diameter of the convex bead portion is equal to or less than the outer diameter of the straight portion and larger than the outer diameter of the concave portion in the turnip portion, and the outer diameter of the concave bead portion is the outer diameter of the turnip portion. It may be equal to or larger than the outer diameter of the concave portion and smaller than the outer diameter of the convex bead portion and the outer diameter of the straight portion.

Further, in the present invention, the height of the S-shaped bead portion, which is half the difference between the outer diameter of the convex bead portion and the outer diameter of the concave bead portion, is 0.7 mm or more and 1.5 mm or less. Can be done.

In the present invention, the shoulder portion may be formed in a convex curved surface shape that rises upward.

In the present invention, the boundary portion connecting the straight portion and the shoulder portion may be formed so that the cross-sectional shape forms an arc shape recessed toward the inside of the mouth portion or the shoulder portion.

In the present invention, the arc-shaped radius at the boundary portion may be 2 mm or more and 4 mm or less.

The bottle-shaped can according to the present invention has an S-shaped bead portion between the cover portion and the shoulder portion, and the S-shaped bead portion has a symmetrical cross-sectional shape and is continuous with each other. Since it is formed by a convex bead portion and a concave bead portion, it is unlikely to be deformed into an elliptical shape even when a lateral load is applied during capping, and by forming the concave bead portion, the axial direction during capping Since a portion that receives the load diagonally upward is generated, the strength against the axial load at the time of capping, that is, the buckling strength can be improved. Further, since a cylindrical straight portion having a length of 1 mm to 7 mm (dimension in the axial direction) is provided between the S-shaped bead portion and the shoulder portion, the S-shaped bead portion or the concave bead portion described above is provided. It is possible to avoid or suppress the influence of strain and stress due to the formation of the shoulder portion on the upper part of the shoulder portion, to avoid a decrease in buckling strength, or to improve the buckling strength. Since the buckling strength can be improved by such a shape or structure, the wall thickness of the bottle-shaped can as a whole can be reduced to reduce the cost and weight.

It is a schematic diagram for demonstrating the process of manufacturing a bottle-shaped can by squeezing and ironing. It is a front view of the bottle type can which concerns on this invention. It is a figure which shows typically the state which the cap is attached to the mouth part by roll-on capping. It is a partially enlarged sectional view which shows an example of an S-shaped bead part and a straight part. It is sectional drawing which further enlarged a part of FIG. It is a figure explaining how the stress (reaction force) is generated when the lateral load by the roll such as a hem tightening roll acts on the mouth part, (a) shows the example which provided the S-shaped bead part, and (a) b) shows an example in which the S-shaped bead portion is not provided. A bottle-shaped can used as an example is shown, (a) is a front view, and (b) is a cross-sectional view of a portion extending from a turnip portion to a shoulder portion. A bottle-shaped can of Comparative Example 1 is shown, (a) is a front view, and (b) is a cross-sectional view of a portion extending from a turnip portion to a shoulder portion. A bottle-shaped can of Comparative Example 2 is shown, (a) is a front view, and (b) is a cross-sectional view of a portion extending from a turnip portion to a shoulder portion. It is a chart which shows the data and the buckling strength about the bottle type can of an Example and each comparative example together.

The bottle-shaped can according to the present invention is a metal can made of a metal plate such as an aluminum plate or a resin-coated aluminum plate, and the bottom plate and the body are integrated through molding processing such as drawing molding and ironing molding. An intermediate body is formed, and the opening end side thereof is subjected to necking processing and screw / curling processing. FIG. 1 schematically shows the manufacturing process. A cylindrical body 4 in which a bottom portion 2 and a body portion 3 are integrated by drawing, redrawing, and redrawing the metal plate 1 as a material. Is formed, and further ironing is performed to deepen the depth of the cylindrical body 4. At that time, the bottom 2 is subjected to a doming process. The opening end side (upper end side) of the cylindrical body 4 is cut off by trimming. Then, it is made into an intermediate 5 through a painting process. The opening end side of the intermediate body 5 is gradually reduced in diameter by necking to form a mouthpiece 6, and the mouthpiece 6 is screwed and curled to obtain a bottle-shaped can 7.

The bottle-shaped can 7 according to the present invention shown in FIG. 2 is manufactured through the above-mentioned steps as an example. Therefore, while the body portion 3 is squeezed and ironed, the mouth portion 6 and the shoulder portion 8 between the body portion 3 and the mouth portion 6 are reduced in diameter, and therefore the body portion 3 has a reduced diameter. On the other hand, the wall thickness of the shoulder portion 8 and the mouth portion 6 is relatively thick. An example of the bottle-shaped can 7 is a bottle-shaped can in which the outer diameter of the body 3 is 53 mm (nominal: 202 diameter) or 66 mm (nominal: 211 diameter) and the outer diameter of the mouth portion 6 is 28 mm to 38 mm.

The bottle-shaped can 7 is configured so that it can be resealed by attaching a cap (not shown) to the mouth portion 6. That is, a curl portion 9 wound outward is formed at the open end of the mouth portion 6, and a male screw portion 10 is formed below the curl portion 9. A turnip portion 11 is formed on the lower side of the male screw portion 10. The cabra portion 11 engages a pilfer proof band (not shown) provided at the lower end of the skirt portion (cylindrical portion) constituting the cap, and when the cap is removed, the pilfer proof is engaged. It is a part for breaking the band from the cap and leaving it on the mouth portion 6, and extends over the entire circumference of the mouth portion 6 below the bulging portion 11a having the outer diameter of the screw thread in the male screw portion 10. It is provided with a formed recess 11b. It should be noted that the recess 11b is separated from the cap and the pilfer proof band left in the mouth portion 6 is loosely fitted so that the consumer can know that the recess 11b is detached from the cap, and as will be described later. It is provided to allow tools for hem tightening to enter.

An S-shaped bead portion 12 is formed following the lower side of the recess 11b. Further, a straight portion 13 is formed between the S-shaped bead portion 12 and the shoulder portion 8. The detailed configuration of the S-shaped bead portion 12 and the straight portion 13 will be described later.

FIG. 3 schematically shows a state in which the cap 14 is attached to the mouth portion 6 of the bottle-shaped can 7 described above by roll-on capping. The cap 14 is put on the mouth portion 6 of the bottle-shaped can 7 which is upright with the mouth portion 6 facing upward, and the cap 14 is pressed by the pressure head 15. In the pressure head 15, a pressing pad at the center portion and a pressure block on the outer peripheral side are integrally formed. The corner portion of the cap 14 is pressed toward the curl portion 9 by the pressure block to be deformed, and the liner 16 provided on the inner surface of the cap 14 is brought into close contact with the curl portion 9 so as to be sandwiched between the curl portion 9 and the curl portion 9. When the pressing pad comes into contact with the top surface of the cap, the cap 13 is pressed in the direction of the central axis of the bottle-shaped can 7 to apply a plug pressure.

Further, the skirt portion (cylindrical portion) of the cap 14 is pressed from the outside by the screw forming roll 17, and in that state, the skirt portion 6 and the screw forming roll 17 are relatively rotated to form the skirt portion. Is pressed against the male screw portion 10 formed on the mouth portion 6 and deformed along the thread groove of the male screw portion 10 to form the female screw portion. Further, the lower end portion of the skirt portion (that is, the portion corresponding to the pilfer proof band) of the cap 14 is brought into close contact with the above-mentioned turnip portion 11 by the hem tightening roll 18 that relatively swivels on the outer peripheral side of the mouth portion 6. And engage with the underside of the bulge 11a described above. Therefore, during roll-on capping, as shown by the thick arrow in FIG. 3, the load (plugging force) A in the direction along the central axis and the twisting force B due to the relative rotation of the bottle-shaped can 7 are used. The lateral force C in the horizontal direction of each of the rolls 17 and 18 acts in combination. In order to prevent or suppress buckling deformation due to such a combined load, the above-mentioned S-shaped bead portion 12 and straight portion 13 are formed on the mouth portion 6.

4 and 5 are partially enlarged cross-sectional views showing an example of the S-shaped bead portion 12 and the straight portion 13, and the S-shaped bead portion 12 is continuous with the lower side of the recess 11b in the turnip portion 11 and is the mouth portion. It is formed by a convex bead portion 12a projecting outward in the radial direction of 6 and a concave bead portion 12b continuous below the convex bead portion 12a and recessed inside the mouth portion 6. These bead portions 12a and 12b are portions having a shape corresponding to an annular concave groove formed over the entire circumference of the mouth portion 6, and the convex bead portion 12a has a cross-sectional shape enlarged in FIG. In addition, it is formed so as to form an arc shape having a predetermined radius Ra (for example, 1 mm to 2 mm), and is a bead when viewed from the outside of the mouth portion 6. Further, the concave bead portion 12b is formed so as to form an arc shape having a predetermined radius Ra as its cross-sectional shape is enlarged and shown in FIG. 5, and has a concave groove shape when viewed from the outside of the mouth portion 6. There is a bead toward the inside of the neck 6. That is, the convex bead portion 12a is a convex bead having an arcuate cross section in which the center of curvature exists inside the mouth portion 6 when viewed from the outside of the mouth portion 6, whereas the concave bead portion 12b is the mouth portion 6. When viewed from the outside, it is a concave groove having an arcuate cross section with a center of curvature on the outside of the mouth portion 6. The convex bead portion 12a and the concave bead portion 12b are connected at a point where the tangent line is approximately 45 ° to 30 ° (angle with respect to the central axis of the bottle-shaped can 7). This is to increase the strength against the vertical plugging force acting during capping. Therefore, the cross-sectional shape of these portions is "S" shaped. In other words, the width and depth of the convex bead portion 12a and the concave bead portion 12b are equal to each other, and their cross-sectional shapes are symmetrical to each other.

Further, the S-shaped bead portion 12 is formed in the radial direction of the mouth portion 6 outside the recess 11b and inside the straight portion 13, that is, between the recess 11b and the straight portion 13. As shown in FIGS. 4 and 5, assuming that the outer diameter of the recess 11b (the outer diameter of the bottom portion of the recess 11b) is D1 and the outer diameter of the straight portion 13 is D4, the maximum outer diameter of the S-shaped bead portion 12 ( The outer diameter of the top of the convex bead portion 12a) D2 is substantially equal to the outer diameter D4 of the straight portion 13, and the minimum outer diameter of the S-shaped bead portion 12 (outer diameter of the bottom portion of the concave bead portion 12b) D3 is the concave portion 11b. It is almost equal to the outer diameter D1 of. Therefore, even if the S-shaped bead portion 12 is provided, the S-shaped bead portion 12 does not protrude to the outer peripheral side from the straight portion 13 and the turnip portion 11, so that the handling of the bottle-shaped can 7 or the capping work is avoided. it can. The height H of the S-shaped bead portion 12 is half the difference between the outer diameter D2 of the convex bead portion 12a and the outer diameter D3 of the concave bead portion 12b, and in the present invention, the height H is 0. It is said to be 7 mm to 1.5 mm. The portion transitioning from the S-shaped bead portion 12 to the recess 11b and the portion transitioning from the S-shaped bead portion 12 to the straight portion 13 are formed so that the cross-sectional shape is arcuate so that stress concentration does not occur. It has become. Further, the portion (boundary portion) 19 connecting the straight portion 13 and the shoulder portion 8 has a concave shape whose center of curvature is outside the mouth portion 6, and the radius of curvature of the concave arc in the cross section is 2 mm. It is more than 4 mm and less than 4 mm.

The straight portion 13 is formed to form the S-shaped bead portion 12 or to avoid or suppress the influence of deformation and stress associated with the elliptical deformation of the S-shaped bead portion 12 on the shoulder portion 8. It is a cylindrical part. Therefore, if the length L of the straight portion 13 in the axial direction is long, the influence of the S-shaped bead portion 12 on the shoulder portion 8 can be avoided, but the height of the bottle-shaped can 7 is the filling equipment, the carton case for transportation, or the automatic. Due to restrictions imposed by the dimensions of guides in vending machines, if the straight portion 13 is lengthened, the length of the body portion 3 becomes shorter and the internal capacity decreases, and conversely, the length L of the straight portion 13 If is short, the influence of the S-shaped bead portion 12 on the shoulder portion 8 cannot be avoided or suppressed, and the effect of improving the buckling strength cannot be obtained. Therefore, in the present invention, the length L of the straight portion 13 is set to 1 mm to 7 mm. Further, the outer diameter of the straight portion 13 is substantially equal to the outer diameter of the above-mentioned turnip portion 11 (outer diameter of the bulging portion 11a). In other words, a cylindrical portion having an outer diameter of the straight portion 13 is formed as the mouth portion 6 on the upper part of the shoulder portion 8, and 1 mm is formed at the base portion (the portion on the shoulder portion 8 side) of the cylindrical mouth portion 6. The above-mentioned S-shaped bead portion 12, the cabra portion 11, the male screw portion 10, and the like are formed on the upper portion of the straight portion 13 having a diameter of about 7 mm. In the present invention, the wall thickness (wall thickness) t of the straight portion 13 is 0.28 mm to 0.34 mm. As described above, since the straight portion 13 is formed by gradually reducing the diameter of the shoulder portion 8, the wall thickness thereof is thicker than the wall thickness of the shoulder portion 8 (particularly the portion on the body portion 3 side). In other words, by making the straight portion 13 thick as described above, it is possible to secure the buckling strength, and the shoulder portion 8 and the body portion 3 can be made thinner than this to reduce the weight and cost. it can.

The bottle-shaped can 7 according to the present invention has a high buckling strength because the S-shaped bead portion 12 and the straight portion 13 are provided on the shoulder portion 8 side portion of the mouth portion 6. Therefore, it is not necessary to form the shoulder portion 8 in a tapered shape in order to improve the buckling strength of the shoulder portion 8. Therefore, as shown in FIG. 4, the shoulder portion 8 has a dome shape having a convex arc shape having a predetermined radius R. It is formed. That is, in the present invention, there are few restrictions on the shape of the shoulder portion 8, and the shape is diversified.

In the bottle-shaped can 7 according to the present invention, since the S-shaped bead portion 12 and the straight portion 13 are provided, the buckling strength against the plugging force (pushing force in the axial direction) at the time of roll-on capping has been conventionally increased. It has improved without any problems, and its action can be explained as follows. FIG. 6 is a diagram for explaining how stress (reaction force) Fr is generated when a lateral load F due to a roll such as a hem tightening roll 18 acts on the mouth portion 6, and FIG. 6A is a diagram for explaining how an S-shaped bead portion 12 is generated. (B) shows an example in which the S-shaped bead portion 12 is not provided. When the S-shaped bead portion 12 is provided, the upper side and the lower side of the convex bead portion 12a form an obliquely upward inclined surface and an obliquely downward inclined surface, and therefore, reaction forces in directions along these inclined surfaces. Fr is generated, and the mouth portion 6 is less likely to be deformed in the radial direction. That is, the elliptical deformation of the mouth portion 6 is unlikely to occur. In addition, a reaction force as a component force in the axial direction (vertical direction) can also be generated on each inclined surface, and a resistance force against a plugging force is generated. Since the generation of stress and strain due to elliptical deformation is avoided or suppressed in this way, the stress concentration when the plugging force acts is relaxed and buckling is less likely to occur. Further, even if the S-shaped bead portion 12 is formed and the influence of deformation and residual stress during processing may extend to the vicinity of the S-shaped bead portion 12, the straight portion 13 is provided. It is avoided or suppressed that such an influence extends to the upper part of the shoulder portion 8. Therefore, local stress concentration does not occur in the upper part of the shoulder portion 8, and buckling is difficult to occur in this respect as well, and the buckling strength against the plugging force is improved.

On the other hand, in the example not provided with the S-shaped bead portion 12 shown in (b), the reaction force Fr generated on the shoulder portion 8 side becomes a force directed in the radial direction of the mouth portion 6, and is simple with respect to the mouth portion 6. Bending stress or compressive stress. Therefore, elliptical deformation of the mouth portion 6 is likely to occur, and drag force against a plugging force in the axial direction is unlikely to occur. Therefore, the effect of improving the buckling strength as described with reference to (a) does not occur.

Next, Examples and Comparative Examples performed to confirm the effect of the present invention will be shown.

FIG. 7 shows a bottle-shaped can used as an example. (A) is a front view, and (b) is a cross-sectional view of a portion extending from the turnip portion 11 to the shoulder portion 8. The data for this bottle-shaped can is as follows. The thickness of the aluminum plate (original plate thickness), which is the material, is 0.35 mm, the outer diameter of the body 3 (outer diameter of the can) is 66 mm, the height (product height) is 131 mm, and the position of the shoulder 8 (from the bottom). The metal thickness on the thick wall (thickest part) after squeezing (after BM) is 0.22 mm, and the metal thickness on the thin wall (thinnest part) after BM is 0.145 mm. The thickness (wall thickness) of the mouth portion 6 after the product is 0.32 mm, the outer diameter of the cover portion 11 (outer diameter of the bulging portion 11a) D4 is 37.8 mm, and the outer diameter D1 of the recess 11b of the cover portion 11 35.4 mm, the length of the mouth portion 6 is 28 mm, the radius of curvature Ra of each bead portion 12a and 12b constituting the S-shaped bead portion 12 is 1.5 mm, and the length of the straight portion 13 is 1.5 mm. The content is 290 ml. The buckling strength of this bottle-shaped can was analyzed. In the analysis, a tapping force was applied to the bottle-shaped can, a lateral load (about 118 N as an example) by a roll for screw forming and hem tightening, and a twisting force due to capping, and a clear buckling occurred. This was done by finding the plugging force at the time. The buckling strength was 1624.2N (Newton).

Comparative Example 1

The front view of the bottle-shaped can of Comparative Example 1 is shown in FIG. 8 (a), and the cross-sectional view of the portion extending from the turnip portion 11 to the shoulder portion 8 is shown in FIG. 8 (b). The bottle-shaped can of Comparative Example 1 is not provided with the S-shaped bead portion 12, whereas the straight portion 13 is longer. Specifically, the portion between the turnip portion 11 and the shoulder portion 8 is the straight portion 13, and the length thereof is 6 mm. The other data for the bottle-shaped can of Comparative Example 1 are the same as the data in the above-described Example except that the S-shaped bead portion 12 is not provided. When the buckling strength of the bottle-shaped can of Comparative Example 1 was analyzed, the buckling strength was 1535.9N (Newton).

Comparative Example 2

The front view of the bottle-shaped can of Comparative Example 2 is shown in FIG. 9 (a), and the cross-sectional view of the portion extending from the turnip portion 11 to the shoulder portion 8 is shown in FIG. 9 (b). Although the bottle-shaped can of Comparative Example 2 is provided with the S-shaped bead portion 12, the straight portion 13 is not provided. Specifically, the portion between the turnip portion 11 and the shoulder portion 8 is the S-shaped bead portion 12, and the size and shape thereof are the same as those of the bottle-shaped can of the above-described embodiment. The other data for the bottle-shaped can of Comparative Example 2 are the same as the data in the above-described Example except that the straight portion 13 is not provided. When the buckling strength of the bottle-shaped can of Comparative Example 2 was analyzed, the buckling strength was 1597.3N (Newton).

The data and buckling strength of each of the above-mentioned Examples and Comparative Examples 1 and 2 are shown in FIG. 10 as a chart. Buckling of the bottle-shaped can occurs in the upper part of the shoulder, more specifically, in the part connected to the mouth, and the cause is considered to be the stress concentration due to the above-mentioned combined load during roll-on capping. In the example in which only the straight portion 13 is formed like the bottle-shaped can of Comparative Example 1, the buckling strength is lower than that of the bottle-shaped cans of Comparative Example 2 and Examples having the S-shaped bead portion 12. It is considered that this is because the lateral load causes elliptical deformation of the mouth portion 6 and the stress locally concentrated on the upper part of the shoulder increases, and the bending stress due to the lateral load concentrates on the upper part of the shoulder. ..

Further, the bottle-type can of Comparative Example 2 had improved buckling strength as compared with the bottle-type can of Comparative Example 1, but could not obtain the buckling strength of the bottle-type can of Example. In Comparative Example 2, since the S-shaped bead portion 12 is provided, the elliptical deformation of the mouth portion 6 is suppressed, and the bending stress due to the lateral load is shared by the S-shaped bead portion 12, as a result. It is considered that the local stress concentration in the upper part of the shoulder portion 8 was relaxed, and as a result, the buckling strength was improved as compared with the bottle-shaped can of Comparative Example 1. However, the buckling strength is lower than that of the bottle-type can of the example, and there is room for improvement in order to reduce the wall thickness and weight of the bottle-type can.

In the bottle-shaped can of the example, the buckling strength was further improved as compared with Comparative Example 2. Although the portion connected to the upper side of the shoulder portion 8 is the straight portion 13, the buckling strength is improved as compared with Comparative Example 1, and the buckling is improved as compared with Comparative Example 2 in which only the S-shaped bead portion 12 is provided. Inferring from the fact that the strength is improved, it is probable that the S-shaped bead portion 12 and the straight portion 13 have some synergistic action. According to the knowledge of the present inventors, when some kind of molding process is performed on a metal plate, it is usual that the portion adjacent to the processed portion is affected by strain, residual stress, etc. It is considered that the straight portion 13 in the bottle-shaped can of the example blocks or suppresses the influence on the shoulder portion 8 due to the formation of the S-shaped bead portion 12. Therefore, in Comparative Example 2, although the S-shaped bead portion 12 suppresses the elliptical deformation of the mouth portion 6, the influence of molding the S-shaped bead portion 12 extends to the upper part of the shoulder portion 8, which is the buckling strength. In the bottle-shaped can of the embodiment of the present invention, the effect of impairing the buckling strength can be blocked or suppressed by the straight portion 13, and as a result, the buckling strength is further increased. It is probable that it could be improved. Therefore, according to the present invention, the buckling strength can be improved by the shape or structure of the mouth portion 6, so that the thickness and weight of the bottle-shaped can can be reduced. Further, since it is not necessary to provide a new processed portion such as a bead on the shoulder portion, it is possible to avoid hindering or restricting the degree of freedom in design.

The present invention is not limited to the specific example described above, and the content may be appropriately set, and the inclination angle of the shoulder portion, the outer diameter and length of the mouth portion, and the like are within the scope of the present invention. It may be set as appropriate as necessary within a range that does not deviate from.

6 ... mouth, 7 ... bottle-shaped can, 8 ... shoulder, 10 ... male screw, 11 ... turnip, 11a ... bulge, 11b ... concave, 12 ... S bead, 12a ... convex bead, 12b ... concave bead part, 13 ... straight part, 17 ... screw forming roll, 18 ... hem tightening roll, 19 ... boundary part.

Claims (7)

The body and the bottom are integrally formed, and a shoulder portion whose outer diameter becomes smaller toward the upper side is continuously formed on the upper portion of the body portion, and a cylindrical nose portion is continuously formed on the upper portion of the shoulder portion. The mouth portion is formed of a male screw portion, a bulge portion continuously formed under the male screw portion, and a cover portion having a concave portion having an outer diameter smaller than that of the bulge portion. In the bottle-shaped can in which
An S-shaped bead portion and a straight portion having a constant outer diameter are formed in this order from the turnip portion side between the turnip portion and the shoulder portion.
The S-shaped bead portion is formed so as to be continuously formed in the recess and have a convex bead portion having an outer diameter larger than that of the recess and a convex bead portion that is continuously formed below the convex bead portion and is recessed inside the mouth portion. It has a concave bead portion whose cross-sectional shape is symmetrical with the cross-sectional shape of the convex bead portion.
The straight portion is formed continuously below the concave bead portion and between the concave bead portion and the shoulder portion so that the length of the mouth portion in the central axis direction is 1 mm or more and 7 mm or less. A bottle-shaped can that is characterized by being made. In the bottle-type can according to claim 1,
The straight portion is a bottle-shaped can having an outer diameter of 26 mm or more and 40 mm or less and a thickness of 0.28 mm or more and 0.34 mm or less. In the bottle-type can according to claim 1 or 2.
The outer diameter of the convex bead portion is equal to or less than the outer diameter of the straight portion and larger than the outer diameter of the concave portion in the turnip portion.
A bottle-shaped can characterized in that the outer diameter of the concave bead portion is equal to or larger than the outer diameter of the concave portion in the turnip portion and smaller than the outer diameter of the convex bead portion and the outer diameter of the straight portion. In the bottle-type can according to any one of claims 1 to 3,
A bottle type characterized in that the height of the S-shaped bead portion, which is half the difference between the outer diameter of the convex bead portion and the outer diameter of the concave bead portion, is 0.7 mm or more and 1.5 mm or less. can. In the bottle-type can according to any one of claims 1 to 4,
The shoulder portion is a bottle-shaped can characterized in that it is formed in a convex curved surface shape that rises upward. In the bottle-type can according to any one of claims 1 to 5,
The boundary portion connecting the straight portion and the shoulder portion is a bottle type characterized in that the cross-sectional shape is formed so as to form an arc shape recessed toward the inside of the mouth portion or the shoulder portion. can. In the bottle-type can according to claim 6,
A bottle-shaped can having an arcuate radius of 2 mm or more and 4 mm or less at the boundary portion.

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