JP7328847B2 - Can bodies and product cans - Google Patents

Description

The present invention provides a bottomed cylindrical can body centered on a can axis, comprising a can bottom and a cylindrical can body extending from the outer circumference of the can bottom to the upper end in the can axis direction. and a cylindrical product can body with a bottom formed from such a can body, and a disk-shaped lid centered on the can shaft attached to the upper end opening of the product can body by winding it. It relates to a product can having a body.

As such can bodies and product cans, for example, Patent Document 1 discloses a can body having a cylindrical shape with a bottom and a can lid that is wound around the opening of the can body and provided with a portion intended for drinking. A can body (beverage can) comprising: a can body having a cylindrical shape extending along the can axis; , a necking portion which is connected to the upper end of the can body in the can axial direction and whose diameter gradually decreases upward in the can axial direction.

Here, in the can body and product can described in Patent Document 1, the outer diameter of the can body is in the range of 55 mm or more and 60 mm or less, and the can from the upper end of the seaming panel of the can lid to the lower end of the necking portion. The axial height is within the range of 9 mm or more and 20 mm or less, and the difference between the outer diameter of the can body and the minimum outer diameter of the necking portion is within the range of 6 mm or more and 8 mm or less. In addition, the height of the can body in the can axis direction is within the range of 120 mm or more and 190 mm or less.

Such a can body is first manufactured by punching a metal plate into a disk shape and drawing it to form a shallow cup-shaped material in a cupping press step using a cupping press machine. Next, the cup-shaped material is redrawed and ironed by a punch in a DI press process using a DI press machine, and stretched in the can axial direction to form a bottomed cylindrical can body as described above. .

In such a can body, while the outer diameter (diameter) of the can body is constant, the can bottom side of the can body is formed as a thin wall portion. In addition, it is known that the portion on the upper end opening side opposite to the can bottom portion is a flange portion that is thicker than the wall portion. For example, Patent Document 2 describes a can body manufactured as a bottle can, in which although the original plate thickness of the metal plate is 0.345 mm to 0.390 mm, the thickness of the flange portion (flange thickness) and the wall portion A DI can with a step of 0.110 mm or less from the thickness of the wall (wall thickness) is described.

Here, in order to form the wall portion and the flange portion having such different thicknesses in the can body 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. At a position corresponding to the flange portion, a recess having a depth that takes into consideration the thickness difference (step) between the wall portion and the flange portion may be formed.

JP 2016-005967 A JP 2018-131261 A

By the way, in recent years, there is a strong demand for further thinning of the can body and the lid body in order to save resources of metal materials forming such can bodies and product cans and to save energy in material manufacturing. For example, in the case of a can body made of an aluminum alloy, the can body may be manufactured by drawing a cup-shaped material from an aluminum alloy plate having a thickness of about 0.230 mm to 0.300 mm. requested.

However, particularly in such a thin-walled can body, the can bottom side of the can body is formed as a wall portion, which is a thin-walled portion, and the upper end opposite to the can bottom portion is formed as described above. The portion on the opening side is a flange portion that is thicker than the wall portion. During this process, the can body is likely to break, which is a so-called breakage phenomenon.

Once such a trunk break occurs, the broken can body remains in the DI press molding machine. Therefore, the molding operation by the DI press molding machine must be temporarily interrupted to remove the broken can body. For this reason, it is inevitable that the productivity of the can body, and thus the productivity of the product cans, is significantly lowered.

SUMMARY OF THE INVENTION The present invention has been made under such a background, and provides a can body capable of suppressing the occurrence of a trunk break even when the thickness is reduced, and a bottomed cylindrical body formed from such a can body. The object of the present invention is to provide a product can having a product can body and a lid.

In order to solve the above problems and achieve such objects, the can body of the present invention has a cylindrical can body with a bottom centered on a can axis, and the can body includes a can bottom and a can bottom. and a cylindrical can body centered on the can axis extending from the outer circumference of the can bottom to the upper end side in the can axis direction, and the outer diameter of the can body is within a range of 55 mm to 60 mm in diameter. , the can body has a can height from the can bottom of the can bottom to the upper end opening of the can body within a range of 150 mm to 190 mm, wherein the can body has a wall portion on the side of the can bottom. The thickness of the flange portion on the upper end opening side is thicker than the thickness, and the flange thickness is the thickness of the flange portion at a position 7 mm from the upper end opening of the can barrel toward the lower end side in the can axial direction. and a wall thickness of the wall portion at a position 79 mm from the can bottom to the upper end in the can axial direction is 60 μm or less, and the can bottom has a central portion A dome portion having a concave curved surface that is recessed toward the upper end side in the can axial direction is formed on the outer peripheral side of the dome portion. is continuously formed in the circumferential direction around the can axis, and the thickness of the dome portion of the can bottom on the can axis is 0.5. It is characterized by being within the range of 270 mm to 0.285 mm .

Further, the product can of the present invention comprises a bottomed cylindrical product can body centered on a can axis, and a disk-shaped product can body centered on the can axis, which is wound and attached to the upper end opening of the product can body. The product can body includes a can bottom and a cylindrical can body centered on the can axis extending from the outer periphery of the can bottom to the upper end side in the can axis direction, The can body has an outer diameter within the range of 55 mm to 60 mm in diameter, and the product can height from the can bottom of the can bottom to the upper end of the lid body is within the range of 150 mm to 190 mm. In the can body, the thickness of the flange portion on the upper end opening side is thicker than the thickness of the wall portion on the can bottom side, and the can shaft is provided on the upper end opening side of the flange portion. A shoulder portion whose diameter is reduced toward the upper end side in the direction of the can, a cylindrical neck portion connected to the upper end of the shoulder portion and centered on the can axis, and a cylindrical neck portion connected to the upper end of the neck portion and extending toward the upper end side in the direction of the can axis. A seamed portion having an enlarged diameter is formed, and the lid is attached to the seamed portion by being wound. The product can step is 74 μm, which is the difference between the flange thickness, which is the thickness of the flange portion, and the wall thickness, which is the thickness of the wall portion at a height of 79 mm from the can bottom to the upper end in the can axial direction. In the can bottom portion, a dome portion having a concave curved surface that is recessed toward the upper end side in the can axial direction is formed in the center portion, and the outer peripheral side of the dome portion is formed at the lower end in the can axial direction. The dome of the can bottom portion is formed continuously in the circumferential direction around the can axis, protruding outward and then toward the upper end side in the can axis direction toward the outer peripheral side in the radial direction with respect to the can axis. The thickness of the portion on the can axis is in the range of 0.270 mm to 0.285 mm .

In the can body and the product can thus configured, the can body step, which is the difference between the flange thickness and the wall thickness, is set to 60 μm or less in the can body, and the difference between the flange thickness and the wall thickness in the product can. The product can level difference is 74 μm or less, and although the flange thickness is thicker than the wall thickness in each case, the level difference is set small.

For this reason, it is possible to reduce the steps of the recessed portions on the outer surface of the punch that is ironed with a plurality of ironing dies in a DI press machine. It is possible to suppress the breakage of the can body caused by being caught by the step. Therefore, it is possible to prevent the molding operation by the DI press molding machine from being interrupted due to the body breaking, and to improve the productivity of can bodies and product cans.

Here, if the can body step, which is the difference between the flange thickness of the can body portion of the can body and the wall thickness of the can body, exceeds 60 μm, the can body is likely to be cut off. In the product can, necking is applied to the flange portion of the can body as described above to form the shoulder portion, the neck portion, and the seam portion. As the diameter is reduced, the thickness of the flange portion increases. Therefore, in the case of product cans, if the product can level difference is 74 μm or less, which is larger than the can body level difference, it can be considered that the can body is prevented from being cut off.
The can bodies and product cans of the present invention are desirably applied to thin-walled can bodies and product can bodies for saving resources and energy as described above. Here, in such a can body and product can body, the thickness on the can axis at the dome portion of the can bottom is the thickness of a plate material made of a metal material before being formed into the can body (plate thickness).
Therefore, the thickness of the dome portion of the can bottom on the can axis is set within the range of 0.270 mm to 0.285 mm. If the thickness of the dome on the can axis is less than 0.270 mm, it may not be possible to ensure the necessary pressure resistance strength of the can body. and energy saving may not be possible.

On the other hand, in such can bodies and product cans, the punch and ironing die of the DI press molding machine form a dome portion in the shape of a concave curved surface recessed toward the upper end in the axial direction of the can at the center portion of the can bottom. is formed on the outer peripheral side of the dome portion, and after protruding toward the lower end side in the axial direction of the can, an annular convex portion directed toward the upper end side in the axial direction as it goes toward the outer peripheral side in the radial direction with respect to the can axis is formed. It is formed continuously in the circumferential direction around the axis. The shape and dimensions of the can bottom are the same between the can body of the can body and the product can body of the product can.

Therefore, in such a can bottom portion, the inner wall portion of the annular protrusion projecting from the dome portion toward the lower end side in the can axis direction is the inner peripheral side of the can body or the product can body in a cross section along the can axis. In the case where the counter portion extends linearly inclined toward the upper end side in the can axis direction as it goes toward the can axis, the counter angle formed by the counter portion with respect to the straight line parallel to the can axis in the cross section is It is desirable to be within the range of 4° to 7°.

If the counter angle is larger than 7°, the counter portion is inclined at a large angle with respect to the can axis, which may impair the compressive strength of the can bottom portion. Conversely, if the counter angle is smaller than 4°, the counter portion becomes nearly parallel to the can axis, and the portions of the punch and ironing die of the DI press molding machine that form the counter portion are located at the bottom surface of the cup-shaped material. There is a risk of cracks occurring in the bottom of the can due to a molded state that cuts vertically into the can.
Moreover, in the can body of the present invention, it is desirable that the can body level difference is 50 μm or more. Moreover, in the product can of the present invention, it is desirable that the product can has a level difference of 60 μm or more.

INDUSTRIAL APPLICABILITY As described above, according to the present invention, even in thin-walled can bodies and product cans, it is possible to suppress the occurrence of body breakage due to the difference in level between the flange portion and the wall portion. It is possible to suppress the interruption of the molding operation by the DI press molding machine and improve the productivity of can bodies and product cans.

1 is a cross-sectional view along the can axis showing an embodiment of a can body of the present invention. FIG. FIG. 5 is an enlarged partial cross-sectional view showing the can bottom portion (A portion in FIG. 1) of the product can of the embodiment shown in FIG. 1 and the embodiment shown in FIG. 4; FIG. 2 is a partial cross-sectional view schematically showing the can body of the embodiment shown in FIG. 1 (however, the thickness of the flange portion is enlarged for explanation). FIG. 2 is a cross-sectional view along the can axis showing a state in which a shoulder portion, a neck portion, and a seam portion are formed on the flange portion of the embodiment shown in FIG. 1; FIG. 5 is a side view showing one embodiment of the product can of the present invention, in which a lid is attached to the winding portion of the can body shown in FIG. 4 ; FIG. 6 is an enlarged cross-sectional view of a portion B in FIG. 5 showing the winding portion of the embodiment shown in FIG. 5;

1 to 3 show one embodiment of the can body of the present invention (however, FIG. 2 is also common to one embodiment of the product can of the present invention), and FIG. 1 shows a state in which a shoulder portion, a neck portion, and a seam portion are formed on the flange portion of the can body of one embodiment. 5 and 6 show an embodiment of the product can of the present invention in which a lid is attached to the seam portion of the can body shown in FIG. 4 by seaming it.

The can body of this embodiment includes a bottomed cylindrical can body 1 centered on a can axis C as shown in FIG. 1 and made of a metal material such as aluminum or an aluminum alloy. That is, the can body 1 has a substantially cylindrical can body 2 centered on the can axis C and closes the opening on the lower end side of the can body 2 (lower side in FIGS. 1 to 3). It is integrally formed with a substantially disk-shaped can bottom 3 .

Of these, the can bottom portion 3 of the can body 1 has a concave curved dome portion 4 which is recessed toward the upper end side in the can axis C direction (the upper side in FIGS. 1 to 3) at the center portion of the can bottom portion 3. An annular convex portion 5 is formed on the outer peripheral side of the dome portion 4, protruding toward the lower end side in the direction of the can axis C, and then heading toward the upper end side in the direction of the can axis C as it goes radially outward with respect to the can axis C. are formed continuously in the circumferential direction around the can axis C. Here, in this embodiment, the thickness t0 on the can axis C of the dome portion 4 of the can bottom portion 3 of the can body 1 is set within the range of 0.270 mm to 0.285 mm.

In addition, the inner wall portion of the annular convex portion 5 protruding from the dome portion 4 toward the lower end side in the can axis C direction is directed toward the inner peripheral side of the can body 1 as shown in FIG. Accordingly, the counter portion 5a extends linearly inclined toward the upper end side in the can axis C direction. In this embodiment, the counter angle θ formed by the counter portion 5a with respect to the straight line L parallel to the can axis C in the cross section along the can axis C is set within the range of 4° to 7°.

On the other hand, the can body 2 has a constant outer diameter D within a range of 55 mm to 60 mm. In addition, the distance from the can bottom 5b of the annular convex portion 5 of the can bottom portion 3 (the position where the annular convex portion 5 protrudes most to the lower end side in the can axis C direction) to the upper end opening 2a of the can body portion 2 in the can axis C direction The can height H1 is set to a constant size within the range of 150 mm to 190 mm, and is set to 157.4 mm in this embodiment.

Further, the can body 2 has a wall portion 2b on the side of the can bottom portion 3 and a flange portion 2c on the side of the upper end opening 2a. The flange thickness t2, which is the thickness of the flange portion 2c in the radial direction with respect to the can axis C, is thicker than the wall thickness t1, and the can body 1 is a step between the wall portion 2b and the flange portion 2c. A stepped portion 2d is formed.

Here, the wall portion 2b extends from the can bottom 5b to the upper end side in the can axis C direction by 132.0 mm (106.0 mm from the boundary between the can body portion 2 and the can bottom portion 3 to the upper end side in the can axis C direction). The flange portion 2c is formed within a range of 15.4 mm from the upper end opening portion 2a to the lower end side in the can axis C direction, and the wall portion 2b and the flange portion 2c are formed within a range of 15.4 mm. The can body stepped portion 2d is formed within a range of 10.0 mm.

A can body step t2-t1 between the flange thickness t2 of the flange portion 2c and the wall thickness t1 of the wall portion 2b is set to 60 μm or less. It is desirable that the can body step t2-t1 between the flange thickness t2 of the flange portion 2c and the wall thickness t1 of the wall portion 2b is 50 μm or more.

Here, in this embodiment, the thickness is measured at eight points at equal intervals in the circumferential direction at a height h1 of 79 mm from the can bottom 5b to the upper end in the can axis C direction, and the average value thereof is the wall thickness t1. and It is desirable that the variation in the wall thickness t1 at this time is ±7 μm. Further, in this embodiment, at a position of height h2 from the can bottom 5b, which is 7 mm from the upper end opening 2a of the can body 2 toward the lower end in the direction of the can axis C, eight thicknesses are formed at equal intervals in the circumferential direction. The thickness is measured, and the average value is taken as the flange thickness t2. It is desirable that the variation in the flange thickness t2 at this time is ±10 μm.

The can body thus formed is adjusted to the predetermined can height H1 by trimming the upper end opening 2a as necessary, and then the flange portion 2c is contracted by necking as shown in FIG. As the diameter is increased, the diameter is reduced toward the upper end opening 2a to form a shoulder portion 6, and a cylindrical neck portion 7 centered on the can axis C is formed so as to continue to the upper end of the shoulder portion 6. be done. Further, from the neck 7 to the upper end opening 2a, the cross section along the can axis C is enlarged in a curved shape toward the upper end in the direction of the can axis C, forming a seam portion 8 that continues to the upper end of the neck 7. be.

After the thus formed can body is filled with contents such as a beverage, a lid body 9 provided with a pull tab (not shown) at the winding portion 8 is wound and tightened as shown in FIGS. It is attached and manufactured into one embodiment of the product can (filled can) of the present invention. That is, this embodiment of the product can also includes a cylindrical product can body 10 with a bottom centered on the can axis C, and a can axis C attached to the upper end opening of the product can body 10 by being wound and tightened. and the disc-shaped lid body 9 having a

The product can body 10 also includes a can bottom portion 3 similar to the can body 1 of the can body, a shoulder portion 6 extending from the outer periphery of the can bottom portion 3 toward the upper end in the can axis C direction, a neck portion 7 and a seam portion 8 . , and a substantially cylindrical can body 2 centered on the can axis C except for the lid body 9 . Here, the outer diameter of the can body 2 is within the range of 55 mm to 60 mm in diameter, the same as the can body 1, and the can height of the product can from the can bottom 5b of the can bottom 3 to the upper end 9a of the lid 9 H2 is in the range of 150 mm to 190 mm, is 155.6 mm in this embodiment, and is slightly lower than the can height H1 of the can body.

Here, the wall thickness t3 of the wall portion 2b in the product can body 10 of this product can is substantially equal to the wall thickness t1 of the can body 1. As shown in FIG. On the other hand, in the necking process, the diameter of the flange portion 2c is reduced and the shoulder portion 6 and the neck portion 7 are formed. is thicker than the flange thickness t2 of the flange portion 2c in the can body 1 of the can body.

The product can level difference t4-t3 between the flange thickness t4 of the flange portion 2e and the wall thickness t3 of the wall portion 2b in the product can body 10 is set to 74 μm or less. The product can level difference t4-t3 between the flange thickness t4 of the flange portion 2e and the wall thickness t3 of the wall portion 2b in the product can main body 10 of this product can is preferably 60 μm or more.

Here, also in the product can of this embodiment, the wall thickness t3 of the wall portion 2b is equally spaced in the circumferential direction at a height h1 of 79 mm from the can bottom 5b toward the upper end in the can axis C direction, as in the case of the can body. The thickness of the can body 2 is measured at eight points, and the average value is taken as the wall thickness t3. It is desirable that the variation in the wall thickness t3 at this time is within ±7 μm.

Further, in the product can of this embodiment, the flange thickness t4 of the flange portion 2e is set at a height h3 of 4 mm from the upper end portion 9a of the lid body 9 to the lower end side in the direction of the can axis C as shown in FIG. The thickness is measured at eight points equally spaced in the circumferential direction, and the average value is defined as the flange thickness t4. The position of this height h3 substantially corresponds to the position of the neck portion 7 described above. In addition, it is desirable that the variation of the flange thickness t4 at this time is within ±10 μm.

Furthermore, in this product can, the shape and dimensions of the can bottom 3 are substantially the same as those of the can body. Therefore, also in the product can of this embodiment, the thickness t0 on the can axis C at the dome portion 4 of the can bottom portion 3 is set within the range of 0.270 mm to 0.285 mm, and the counter portion 5a is set to the can axis C. The counter angle θ formed with respect to the straight line L parallel to the can axis C in the cross section along C is also within the range of 4° to 7°.

In the can body and the product can thus configured, the can body step t2-t1, which is the difference between the flange thickness t2 of the can body 1 and the wall thickness t1, of the can body is set to 60 μm or less, and in the product can, The product can level difference t4-t3, which is the difference between the flange thickness t4 of the product can body 10 and the wall thickness t3, is set to 74 μm or less. However, the can body step t2-t1 and the product can step t4-t3 are set small.

For this reason, it is possible to reduce the steps of the recesses on the outer surface of the punch that is ironed with a plurality of ironing dies in the DI press machine, so that even when the can body 1 is formed from a thin metal plate, , it is possible to prevent the can main body 1 from being caught by the step and breaking the can body 1. Therefore, it is possible to suppress the interruption of the molding operation by the DI press molding machine due to the cutoff, so that the productivity of the can body can be improved, and the productivity of the product can can be improved. becomes.

Here, if the can body step t2-t1, which is the difference between the flange thickness t2 of the can body 2 of the can body 1 and the wall thickness t1 of the can body, exceeds 60 μm, the can body 1 is likely to break. end up In the product can, the necking process is applied to the flange portion 2c of the can main body 1 of the can body as described above to reduce the diameter of the flange portion 2c. If the product can height difference t4-t3 is 74 μm or less, which is larger than t2-t1, it can be said that the can body was prevented from being cut off in the DI press process by the DI press molding machine.

On the other hand, in such can bodies and product cans, the can body 1 and the can bottom 3 of the product can body 10 are formed at their centers in the direction of the can axis C by the punches and ironing dies of the DI press molding machine as described above. A dome portion 4 having a concave surface that is recessed toward the upper end side is formed, and on the outer peripheral side of this dome portion 4, after protruding toward the lower end side in the direction of the can axis C, the dome portion 4 protrudes toward the outer peripheral side in the radial direction with respect to the can axis C. An annular projection 5 directed toward the upper end in the direction of the can axis C is continuously formed in the circumferential direction around the can axis C. As shown in FIG. Here, the shape and dimensions of the can bottom 3 are substantially the same between the can body 1 and the product can body 10 as described above.

In the can body and the product can of this embodiment, the inner wall portion of the annular protrusion 5 projecting from the dome portion 4 of the can bottom portion 3 toward the lower end side in the can axis C direction is The can body 1 or the product can body 10 has a counter portion 5a extending linearly inclined toward the upper end in the direction of the can axis C toward the inner peripheral side of the can body 1 or the product can body 10. A counter angle θ formed with respect to a straight line L parallel to the is set within a range of 4° to 7°.

Therefore, according to the present embodiment, it is possible to prevent the productivity of the can bodies and product cans from being impaired due to cracks in the can bottom 3 during the DI pressing process, while ensuring the compressive strength of the can bottom 3 . . That is, if the counter angle θ is greater than 7°, the counter portion 5a may be inclined at a large angle with respect to the can axis C, and the pressure resistance strength of the can bottom portion 3 may be impaired.

On the other hand, when the counter angle θ is smaller than 4°, the counter portion 5a becomes nearly parallel to the can axis C, and the punch of the DI press forming machine and the portion of the ironing die forming the counter portion 5a are cup-shaped. There is a risk that the can bottom 3 will be cracked due to the molded state in which the bottom of the material is vertically cut.

Further, in this embodiment, the thickness t0 on the can axis C at the dome portion 4 of the can bottom portion 3 is set within a range of 0.270 mm to 0.285 mm. Since the thickness t0 of is substantially equal to the thickness of the metal plate to be formed into the can body, the can body and the product can can be formed from a thinner metal plate. Therefore, according to the present embodiment, it is possible to save resources of metal materials for forming can bodies and product cans, and to save energy in manufacturing such materials.

Here, if the thickness t0 of the dome portion 4 on the can axis C is less than 0.270 mm, there is a risk that the can body 1 may not be able to secure the necessary pressure resistance strength. There is also a risk that the pressure resistance strength will be insufficient. On the other hand, if the thickness t0 of the dome portion 4 on the can axis C exceeds 0.285 mm, the thickness of the metal plate formed into the can body or the product can is also increased, resulting in sufficient resource saving. There is a risk that it will not be possible to improve efficiency and save energy.

Next, the effects of the present invention will be demonstrated by giving examples of the present invention. In this embodiment, seven types of can body 1 are formed by DI press molding from three types of metal plates made of an aluminum alloy material with a plate thickness of 0.285 mm and varying material strengths of 27k, 26k, and 25k. One million cans were molded by the machine, the flange thickness t2 and the wall thickness t1 were measured by the above-described measurement method, and the can body step t2-t1 was calculated. These are shown in Table 1 as Examples 1-7 together with the counter angle. It should be noted that Examples 1 to 3, Examples 4 to 6, and Example 7 have different counter angles.

Next, a shoulder portion 6 and a neck portion 7 are formed on these can bodies by necking, a seam portion 8 is formed, and a lid body 9 is seamed and attached to manufacture a product can body 10 of the product can. The product can level difference t4-t3 was calculated by measuring the flange thickness t4 and the wall thickness t3 by the measurement method described above. Furthermore, the drop pressure strength and column strength of these product cans were calculated by simulation and measured values were measured. This result is also shown in Table 1.

In addition, as comparative examples for Examples 1 to 7, three types of can bodies were prepared from three types of metal plates made of an aluminum alloy material having a plate thickness of 0.285 mm and varying the material strength in the same manner as in Examples 1 to 6. One million can bodies were molded by a DI press molding machine, and the flange thickness t2 and wall thickness t1 were similarly measured to calculate the can body step t2-t1.

Furthermore, in these comparative examples, the product can body 10 of the product can was manufactured by attaching the lid 9 to the molded can body, and the flange thickness t4 and the wall thickness t3 were similarly measured to determine the product can height difference t4-t3. was calculated. Also in these comparative examples, the drop pressure resistance and column strength of product cans were calculated by simulation and measured values were measured. The results are also shown in Table 1 as Comparative Examples 1-3.

It should be noted that the ratio in the column of compressive strength is the ratio when the result of Comparative Example 1 is taken as 100%. In the examples and comparative examples, the fact that the flange thickness t4 and wall thickness t3 of the product can are thicker than the flange thickness t2 and wall thickness t1 of the can also includes the coating thickness.

At this time, in the can bodies of Examples 1 to 7, only 5 cans out of 1,000,000 cans were broken during molding by the DI press molding machine. On the other hand, in the can bodies of Comparative Example 1, 50 out of 1,000,000 cans were broken, and in the can bodies of Comparative Example 2, 500 or more out of 1,000,000 cans were broken. Furthermore, even in the can bodies of Comparative Example 3, body breakage occurred in more than 500 cans out of 1,000,000 cans. Further, in the product cans produced from the molded can body, the compressive strength and column strength of Comparative Example 3 were smaller than those of Examples 1 to 7 and Comparative Examples 1 and 2. In Examples 1 to 6 and Comparative Examples 1 to 3, cracks did not occur in the can bottom portion 3 .

Next, a metal plate made of an aluminum alloy material having a material strength of 25 k and a plate thickness of 0.285 mm as in Examples 3, 6 and 7, a flange thickness t2, a wall thickness t1, and a can body The same number of four types of can bodies as in Examples 3, 6, and 7 having a step t2-t1 but different counter angles were molded.

Further, the shoulder portion 6 and the neck portion 7 are formed by necking the thus-formed can body, and the tightening portion 8 is formed. manufactured. The flange thickness t4 and wall thickness t3 of the product can body 10 were also measured, the product can height difference t4-t3 was calculated, and the drop pressure strength and column strength of the product can were calculated by simulation and measured values were measured. The results are shown in Table 2 as Comparative Examples 11-14.

Of these Comparative Examples 11 to 14, in Comparative Examples 11 and 12, the counter angle was larger than 7°, and the counter portion 5a was inclined at a large angle with respect to the can axis C. Ta. Further, in Comparative Examples 13 and 14, although the product cans manufactured from the molded can bodies were able to secure the pressure resistance and column strength, the counter angle was smaller than 4°, so the DI of the can body was low. During molding by a press molding machine, cracks were generated in the can bottom 3 in one can out of one million cans. Since a product can having a crack in the can bottom 3 is a defective product with a functional defect, even one can cannot be distributed to the market.

REFERENCE SIGNS LIST 1 can body 2 can body 2a top opening of can body 2 2b can body and product can wall 2c can body flange 2d can body step 2e product can flange 3 can bottom 4 dome 5 annular Convex portion 5a Counter portion 5b Can bottom 6 Shoulder portion 7 Neck portion 8 Winding portion 9 Lid 9a Upper end of lid 9 10 Product can body C Can axis D Outer diameter of can body 2 H1 Can height H2 Can height of the product can h1 Height of 79 mm from the can body and the can bottom 5b of the product can to the upper end side in the can axis C direction h2 Height of 150 mm from the can bottom 5b of the can body to the upper end side in the can axis C direction h3 Lid body 4 mm height from the upper end 9a of 9 to the lower end in the can axis C direction t0 Thickness on the can axis C at the dome portion 4 of the can bottom 3 t1 Wall thickness of the can body t2 Flange thickness of the can body t3 Wall of the product can Thickness t4 Flange thickness of product can L Straight line parallel to can axis C θ Counter angle

Claims (6)

Having a cylindrical can body with a bottom centered on the can axis,
The can body includes a can bottom and a cylindrical can body centered on the can axis extending from the outer periphery of the can bottom to the upper end in the can axis direction,
The can body has an outer diameter within the range of 55 mm to 60 mm in diameter, and a can height from the can bottom to the upper end opening of the can body within the range of 150 mm to 190 mm. and
In the can body, the thickness of the flange portion on the upper end opening side is thicker than the thickness of the wall portion on the can bottom side,
The flange thickness, which is the thickness of the flange portion at a position 7 mm from the upper end opening of the can body to the lower end in the can axial direction, and the wall portion at a position 79 mm from the can bottom to the upper end in the can axial direction. The can body step, which is the difference from the wall thickness, which is the thickness of the can , is 60 μm or less,
The bottom of the can has a concavely curved dome portion that is recessed toward the upper end in the axial direction of the can at the center. An annular convex portion directed toward the upper end side in the can axis direction toward the outer peripheral side in the radial direction with respect to the can axis is formed continuously in the circumferential direction around the can axis,
A can body, wherein the thickness of the dome portion of the can bottom portion on the can axis is in the range of 0.270 mm to 0.285 mm . The bottom of the can has a concavely curved dome portion that is recessed toward the upper end in the axial direction of the can at the center. An annular convex portion directed toward the upper end side in the can axis direction toward the outer peripheral side in the radial direction with respect to the can axis is formed continuously in the circumferential direction around the can axis,
The inner wall portion of the annular projection protruding from the dome portion toward the lower end in the can axial direction is straight toward the upper end in the can axial direction toward the inner peripheral side of the can main body in a cross section along the can axis. It is considered to be a counter part that extends in a slanted shape,
2. The can body according to claim 1, wherein a counter angle formed by the counter portion with respect to a straight line parallel to the can axis in the cross section is within a range of 4° to 7°. 3. The can body according to claim 1, wherein the can body step is 50 [mu]m or more. A cylindrical product can body with a bottom centered on a can axis, and a disk-shaped lid centered on the can axis and attached to the upper end opening of the product can body by winding it,
The product can body includes a can bottom and a cylindrical can body centered on the can axis extending from the outer periphery of the can bottom to the upper end in the can axis direction,
A product can in which the outer diameter of the can body is within the range of 55 mm to 60 mm in diameter, and the product can height from the can bottom of the can bottom to the upper end of the lid is within the range of 150 mm to 190 mm. There is
In the can body, the thickness of the flange portion on the upper end opening side is thicker than the thickness of the wall portion on the can bottom side,
On the upper end opening side of the flange portion, a shoulder portion whose diameter is reduced toward the upper end side in the can axis direction, a cylindrical neck portion connected to the upper end of the shoulder portion and centered on the can axis, A winding portion is formed which continues to the upper end of the neck portion and whose diameter increases toward the upper end in the can axial direction, and the lid body is attached to the winding portion by winding it tightly,
The flange thickness, which is the thickness of the flange portion at a position 4 mm from the upper end of the lid to the lower end in the can axial direction, and the wall at a height of 79 mm from the bottom to the upper end in the can axial direction. The product can step, which is the difference from the wall thickness, which is the thickness of the part , is 74 μm or less,
The bottom of the can has a dome portion with a concave curved surface that is recessed toward the upper end in the can axial direction. An annular convex portion directed toward the upper end side in the can axis direction toward the outer peripheral side in the radial direction with respect to the can axis is formed continuously in the circumferential direction around the can axis,
A product can, wherein the thickness of the dome portion of the can bottom on the can axis is in the range of 0.270 mm to 0.285 mm. The bottom of the can has a concavely curved dome portion that is recessed toward the upper end in the axial direction of the can at the center. An annular convex portion directed toward the upper end side in the can axis direction toward the outer peripheral side in the radial direction with respect to the can axis is formed continuously in the circumferential direction around the can axis,
The inner wall portion of the annular projection protruding from the dome portion toward the lower end side in the can axis direction is directed toward the upper end side in the can axis direction as it goes toward the inner peripheral side of the product can body in a cross section along the can axis. It is a counter part that extends in a straight line,
5. The product can according to claim 4, wherein a counter angle formed by the counter portion with respect to a straight line parallel to the can axis in the cross section is within a range of 4° to 7°. 6. The product can according to claim 4 or 5, wherein the product can level difference is 60 [mu]m or more.

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