can body

Abstract

Both a predetermined filling amount of contents and pressure resistance and drop strength are ensured. A can body is a bottomed cylindrical aluminum alloy can body including a can bottom 11 and a can body 12, the can bottom including: a dome portion 111 provided at a center portion of the can bottom; and an annular protrusion portion 112 provided at an outer peripheral edge of the dome portion, the annular protrusion portion being continuously provided at the dome portion and including: a recessed portion 112A having a curved surface projecting toward a radially outer side of the can body; a grounding portion 112B supporting the can body; an inner peripheral wall portion 112C from the grounding portion to the recessed portion; the can body having an outer diameter in a range of 50 mm or more and 59 mm or less, and a height from the grounding portion to an upper end of the can body in a range of 120 mm or more and 190 mm or less, and in a longitudinal cross section including a can axis, a recessed depth of 0.5 mm or more and 0.8 mm or less, and a grounding diameter of φ 44.0 mm or more and φ 47.0 mm or less.

Description

Technical Field

[0001] This invention relates to tanks, and more particularly to tanks in which bottom reshaping has been performed at the bottom. Background Technology

[0002] Traditionally, aluminum alloy deep-drawn thin-walled cans (two-piece cans) have been well-known as containers for filling beverages and other contents. The can body of an aluminum alloy deep-drawn thin-walled can is made by punching aluminum alloy sheets into a circular shape, then deep-drawing them into a shallow, bottomed cylindrical cup-shaped component, and then further deep-drawing and thinning the cup-shaped component to form the can bottom and body in one piece.

[0003] From a resource-saving perspective, such cans require thinner can bodies. Especially when the contents are carbonated beverages, certain modifications are made to the can bottom to ensure sufficient pressure resistance even with a thinner can. Specifically, a dome-shaped indentation extending inwards from the center of the bottom is incorporated, along with an annular protrusion around the dome. The annular protrusion is then reshaped at the bottom to ensure pressure resistance even with a thinner can (e.g., Patent Document 1). Furthermore, to withstand impacts during market distribution, such cans also require sufficient drop strength (e.g., Patent Document 2).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2000-190961

[0007] Patent Document 2: U.S. Patent No. 7740148

[0008] Patent Document 3: Specification of Chinese Utility Model Registration No. 203903013 Summary of the Invention

[0009] The technical problem that the invention aims to solve

[0010] However, in recent years, due to fashionable design, there has been an increasing trend of using slender two-piece cans with smaller diameters (e.g., 204 diameter) to replace ordinary two-piece cans (211 diameter) containing contents such as beer (e.g., Patent Document 3).

[0011] The aforementioned bottom reshaping, which deforms the annular protrusion inwards towards the inside of the tank, causes the liquid level to rise when the reshaped tank is filled, even if the amount of content is the same as before the bottom reshaping. This affects the filling volume. This effect is greater for smaller diameter tanks like the 204mm tank than for the 211mm tank. In other words, the deformation caused by bottom reshaping in smaller diameter tanks leads to greater fluctuations in the liquid level of the filling material compared to a 211mm tank. Therefore, it presents a problem of not being able to meet all the requirements for ensuring the predetermined filling volume, pressure resistance, and drop strength.

[0012] The present invention was made in view of the above circumstances, and one of its objectives is to solve the aforementioned problems. That is, the objective of the present invention is to ensure both the predetermined filling amount of the contents and the pressure resistance and drop strength, etc.

[0013] Technical solutions to solve technical problems

[0014] One aspect of the present invention is to provide a can body, a bottomed cylindrical aluminum alloy can body, comprising: a can bottom; a cylindrical can body extending from the outer periphery of the can bottom along a can axis and centered on the can axis; wherein the can bottom includes: a dome disposed at the center of the can bottom; an annular protrusion continuously projecting outward from the outer peripheral edge of the dome along the can axis direction toward the outer side of the can body; the annular protrusion is continuously disposed on the dome and includes: a recess having a curved surface protruding radially outward toward the can body; a grounding portion supporting the can body; an inner peripheral wall portion from the grounding portion to the recess; the outer diameter of the can body is in the range of 50 mm to 59 mm, the can height from the grounding portion to the upper end of the can body is in the range of 120 mm to 190 mm, and in a longitudinal section including the can axis, the recess depth is 0.5 mm to 0.9 mm, and the grounding diameter is φ44.0 mm to 47.0 mm. Here, the recess depth is the radial distance between the portion of the outer surface of the can body on the recess that is furthest from the can axis and the portion of the outer surface of the can body on the grounding portion that is closest to the can axis, and the grounding diameter is the diameter of the most protruding part of the grounding portion in the direction of the can axis downward.

[0015] The effects of the invention

[0016] According to the present invention, both the predetermined filling amount of the contents and the pressure resistance and drop strength can be ensured. Attached Figure Description

[0017] Figure 1 It is a longitudinal cross-sectional view along the tank axis;

[0018] Figure 2 yes Figure 1Enlarged cross-sectional view of a portion of the bottom of the tank shown;

[0019] Figure 3 This is an enlarged cross-sectional view of the bottom of the aluminum alloy deep-drawn and thinned can in a modified example 1 of the present invention;

[0020] Figure 4 This is an enlarged cross-sectional view of the bottom of the aluminum alloy deep-drawn and thinned can in a modified example 1 of the present invention;

[0021] Figure 5 This is a schematic table showing the test results of dropping the can by changing the grounding diameter in the embodiments and comparative examples of the aluminum alloy deep drawing and thinning can of the present invention.

[0022] Figure 6 This is a schematic table showing the test results of changing the recess depth and dropping the can body in relation to embodiments and comparative examples of aluminum alloy deep-drawn and thinned cans according to the present invention.

[0023] Explanation of reference numerals in the attached figures:

[0024] 10: Tank body, 11: Tank bottom, 12: Tank body, 20: Reforming roller, 111: Dome, 111A: First dome, 111B: Second dome, 111C: Conical part, 112: Annular protrusion, 112A: Recess, 112B: Grounding part, 112C: Inner peripheral wall, 113: Grounding part, 113A: First convex curved surface, 113B: Second convex curved surface, 121: Neck, 121A: Concave curved surface, 121B: Convex curved surface, 121C: Concave curved surface, 123: Flange. Detailed Implementation

[0025] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the following description, the same symbols denote parts with the same function, and repeated descriptions in the drawings are omitted as appropriate.

[0026] Figure 1 This is a longitudinal cross-sectional view of tank 10 along tank axis O, showing the outline of tank 10. Additionally, Figure 1 The thickness of the tank body 10 is omitted, and its cross-sectional shape is shown in a line drawing.

[0027] like Figure 1 As shown, the can body 10 is formed into a bottomed cylindrical shape, including: a can bottom 11; and a cylindrical can body 12 extending from the outer periphery of the can bottom 11 along the can axis O and centered on the can axis O.

[0028] The bottom of the tank 11 has a dome 111 and an annular protrusion 112. The dome 111 is located at the center of the bottom of the tank 11, and the annular protrusion 112 continuously protrudes from the outer peripheral edge of the dome 111 along the direction of the tank axis O and outwards from the outside of the tank body 10 to support the tank body 10.

[0029] An annular protrusion 112 is continuously provided on the dome 111, including: a recess 112A having a curved surface protruding radially outward from the tank body 10; a grounding portion 112B supporting the tank body 10; and an inner peripheral wall portion 112C from the grounding portion 112B to the recess 112A (see reference). Figure 2 ).

[0030] (Implementation Method)

[0031] The can body of the present invention is, for example, an aluminum alloy deep-drawn and thinned can.

[0032] The can body in this embodiment is an aluminum alloy deep-drawn and thinned can, and... Figure 1 The tank 10 shown has the same structure, but the shape and size of each part have been optimized. Therefore, refer to the following... Figure 1 The shape and dimensions of the can body 10 of the aluminum alloy deep-drawn and thinned can as described in this embodiment will be explained.

[0033] The can body 10 of the aluminum alloy deep-drawn and thinned can is made by, for example, punching an aluminum alloy sheet into a round shape, then deep-drawing it into a bottomed cylindrical cup-shaped part, and then deep-drawing and thinning the cup-shaped part to integrally form the can bottom 11 and the can body 12. Then, the open end of the can body 12 is trimmed, necked, and flanged.

[0034] The can body 10 includes: a can bottom 11; a cylindrical can body 12 extending from the outer periphery of the can bottom 11 along the can axis O and centered on the can axis O; the can bottom 11 and the can body 12 form a bottomed cylindrical shape. The can bottom 11 and the can body 12 have the same shape around the can axis O.

[0035] The height of the tank body 10 from the grounding part of the tank bottom 11 (described later) to the upper end of the tank body 12 is within the range of 120mm to 190mm. Figure 1 The example shown is 155.0 mm.

[0036] The outer diameter of the tank body 12 is between 50mm and 59mm. Figure 1 The example shown is 57.2mm.

[0037] Figure 2 An enlarged cross-sectional view of the bottom of the tank 11 was shown. Figure 2 yes Figure 1 A magnified cross-sectional view of a portion of the bottom 11 of the tank shown.

[0038] The bottom of the can 11 has a rounded top 111 and an annular protrusion 112.

[0039] like Figure 2As shown, the dome 111 is provided at the center of the bottom of the can 11 and has multiple curved surfaces including a dome-shaped concave surface that is recessed into the can body 12 along the can axis O.

[0040] Figure 1 In the example, the dome 111 is composed of two curved surfaces including a first dome 111A and a second dome 111B and a conical portion 111C.

[0041] The first dome 111A has a concave surface with a radius of curvature R1 at the center of the bottom 11, recessed inward toward the body 12 along the direction of the can axis O. The second dome 111B is located around the first dome 111A and is continuously disposed radially outside the outer periphery of the first dome 111A, having a concave surface with a radius of curvature R2 recessed inward toward the body 12. The radius of curvature R2 of the second dome 111B is smaller than the radius of curvature R1 of the first dome 111A.

[0042] The aluminum alloy thickness (hereinafter referred to as "aluminum alloy thickness") of the first dome 111A on the can shaft O is preferably between 0.18 mm and 0.26 mm. If the aluminum alloy thickness is too small, can body breakage during deep drawing and thinning processes increases, risking a decrease in yield. Conversely, if it is too large, material consumption increases, neither of which meets the requirement of resource conservation. Therefore, by keeping the aluminum alloy thickness within the above range, it is possible to achieve can body thinning, save resources, suppress can body breakage, and improve yield.

[0043] The dome 111 can be like Figure 1 As in the example, multiple surfaces with different radii of curvature can be formed. In addition to forming surfaces with a gradually increasing radius of curvature, surfaces with a single radius of curvature can also be formed. Furthermore, the well-known dome shape can also be applied.

[0044] The tapered portion 111C is a surface provided around the outer periphery of the second dome 111B. It is configured such that one end is continuous with the outer peripheral edge of the second dome 111B, and the other end is continuous with the recessed portion 112A (described later). Thus, the tapered surface gradually increases in diameter from the second dome 111B toward the recessed portion 112A. The tapered portion 111C can be straight in the longitudinal section containing the tank shaft O, or it can be a curved surface protruding toward the inner or outer side of the tank body 10.

[0045] The annular protrusion 112 protrudes outward from the outer periphery of the dome 111 along the direction of the tank axis O. Figure 2 In the example, the annular protrusion 112 includes: a recess 112A; a grounding portion 112B; and an inner peripheral wall portion 112C.

[0046] The recess 112A is continuously provided on the outer peripheral edge of the dome 111 and has a curved surface that protrudes radially outward from the tank body 10. The radius of curvature of the curved surface of the recess 112A is preferably 0.3 mm to 1.2 mm. Preferably, the height of the recess 112A, i.e., the distance from the grounding portion 113 of the grounding portion 112B (the portion of the grounding portion 112B that protrudes downward in the direction of the tank axis O and contacts the grounding surface G) to the portion of the recess 112A on the outer surface of the tank body 10 furthest from the tank axis O in the direction of the tank axis O, is 1 mm to 4 mm. This ensures sufficient internal capacity and pressure resistance. Alternatively, the recess 112A may have multiple curved surfaces with different radii of curvature, each ranging from 0.3 mm to 1.2 mm.

[0047] The grounding part 112B is connected to the grounding ground G when the tank body 10 is placed on the slightly horizontal grounding ground (horizontal plane) G, thus supporting the tank body 10. The grounding part 112B has two convex curved surfaces on both sides separated by the grounding part 113.

[0048] Specifically, such as Figure 1 and Figure 2 As shown, the grounding portion 112B has a first convex curved surface 113A closer to the can shaft O than the grounding portion 113; and a second convex curved surface 113B farther from the can shaft O than the grounding portion 113. The radius of curvature R3 of the first convex curved surface 113A is preferably 0.4 mm or more and 0.7 mm or less, and the radius of curvature R4 of the second convex curved surface 113B is preferably 1.6 mm or more and 2.2 mm or less. This ensures drop strength.

[0049] The inner peripheral wall portion 112C is disposed between the grounding portion 112B and the recessed portion 112A, and is inclined radially decreasing from the recessed portion 112A toward the grounding portion 112B along the direction of the can axis O. The inclination angle of the inner peripheral wall portion 112C, that is, the angle formed by the inner peripheral wall portion 112C and the can axis O, is preferably 15° or more and 30° or less.

[0050] The annular protrusion 112 is in Figure 1 The longitudinal section containing the can shaft O shown is preferably formed with a recess depth of 0.5 mm to 0.9 mm and a grounding diameter of φ44.0 mm to 47.0 mm.

[0051] Here, the recess depth d1 is the radial distance between the part of the outer surface of the tank 10 on the recessed portion 112A that is farthest from the tank axis O and the part of the outer surface of the tank 10 on the grounding portion 112B that is closest to the tank axis O.

[0052] In addition, the grounding diameter is the diameter of the grounding part 113 on the grounding part 112B.

[0053] Figure 1 In the example, the recess depth d1 is set to 0.7mm, and the grounding diameter is set to φ45.5mm.

[0054] The above structure allows for a balance between internal capacity, pressure resistance, and drop strength, and ensures these balances effectively.

[0055] The can body 12 is formed as a cylinder extending from the outer periphery of the can bottom 11 along the can axis O, centered on the can axis O. The neck 121 at the upper end of the can body 12 is formed such that the outer diameter of the can body 12 gradually decreases along the can axis O towards the upper part of the can body. A can lid (not shown) with a smaller diameter than the can body 12 can be provided on the neck 121. Furthermore, Figure 1 In the example, the minimum outer diameter on the neck 121 is 52.4 mm.

[0056] The neck 121 is provided with: a concave surface 121A at the upper end with a radius of curvature r1 that is recessed radially inward into the tank 10; and a convex surface 121B at the lower end with a radius of curvature r2 that is protruding radially outward from the tank 10. Furthermore, between the concave surface 121A at the upper end and the convex surface 121B at the lower end, there is a concave surface 121C with a radius of curvature r3 that is recessed radially inward into the tank 10. A flange portion 123 is formed at the open end of the tank 10, i.e., the upper end of the neck 121. Figure 1 In the example, the radius of curvature r1 is 1.5 mm, the radius of curvature r2 is 5.0 mm, and the radius of curvature r3 is 10.0 mm. The values ​​of each radius of curvature are just examples and are not limited to these values.

[0057] (Variation Example 1)

[0058] The following describes a variation of the tank in the embodiment. Figure 3 The image shows an enlarged view of the tank bottom 11 on a longitudinal section along the tank axis O of this modified example 1. Figure 3 The diagram does not include the shaft O of the tank.

[0059] like Figure 3 As shown, compared with the tank body of the above embodiment, in this modified example, the radius of curvature of the recess 112A is larger, and the distance of the inner peripheral wall portion in the longitudinal section is shorter.

[0060] In order to obtain such Figure 3 The annular protrusion 112 shown is, for example, as Figure 4As shown, a predetermined reforming roller 20 is used for bottom reforming. That is, for the annular protrusion extending outward from the second dome 111B of the dome 111 along the can axis O, the reforming roller 20 is pressed radially outward, deforming the annular protrusion. As a result, while forming a recess 112A corresponding to the shape and pressing amount of the reforming roller 20, a tapered portion 111C is formed on the upper side of the recess 112A, and an inner peripheral wall portion 112C is formed on the lower side of the recess 112A.

[0061] Furthermore, this modified example illustrates the bottom re-forming by forming an annular protrusion using a re-forming roller, but the method of bottom re-forming is not limited to this, and other methods may be appropriately used.

[0062] Figure 5 and Figure 6 This is a schematic table showing the results of the drop test on tank 10 with adjusted dimensions. Figure 5 and Figure 6 The results of two types of drop tests are presented: a single drop test and a whole box drop test. Each drop test was conducted under the following conditions.

[0063] (1) Single drop test

[0064] As an example, the experiment involved filling the can 10 with 335ml of carbonated water, sealing it with the lid, shaking it thoroughly, and then dropping it individually.

[0065] In a single drop test, a piece of cardboard used for packaging product cans is laid on a gray cast iron block with its top surface machined into a plane at an inclination angle of 10°, serving as the drop surface. With the can body 10 positioned with the grounding part 112B as its underside, and the can axis O in the vertical direction, the can is freely dropped from a height of 20 cm from the grounding part 112B to the drop surface.

[0066] (2) Whole box drop test

[0067] As an example, the experiment involved placing 24 cans 10, each filled with 355ml of carbonated water and sealed with a lid, into a rectangular cardboard box used for transporting product cans. The cans were then allowed to vibrate fully before being dropped.

[0068] In the whole-box drop test, a 20mm thick frosted iron plate made of SPCC was placed on a horizontal concrete surface as the drop surface. Relative to this drop surface, the cardboard box was tilted at 20° to the horizontal with the grounding part 112B of the can 10 inside as the bottom side, and was dropped freely from a height of 15cm with the shortest distance between the cardboard box and the iron plate.

[0069] Figure 5 and Figure 6 The table shown includes the following: “recess depth”, which represents the radial distance between the portion of the outer surface of the tank body 10 on the recess 112A that is furthest from the tank axis O and the portion of the outer surface of the tank body 10 on the grounding portion 112B that is closest to the tank axis O; “grounding diameter”, which represents the diameter of the grounding portion 113 on the grounding portion 112B; “aluminum alloy thickness”, which represents the aluminum alloy thickness of the first dome 111A on the tank axis O; “tank height”, which represents the tank height from the grounding portion 112B to the upper end of the tank body 12; “tank body outer diameter”, which represents the outer diameter of the tank body 12; “filling material specifications”, which use “liquid temperature” and “internal pressure” to describe the carbonated water filled inside the tank body 10; and “evaluation”, which uses the result of evaluating the deformation of any part of the dome 111 or the annular protrusion 112.

[0070] Figure 5 The results of drop tests were presented for a can body 10 of an embodiment and a comparative example, which was formed with an aluminum alloy thickness of 0.22 mm, a can height of 155.3 mm, a recess depth of 0.68 mm, and an outer diameter of 57.2 mm, and whose grounding diameter was changed by 0.5 mm in successive increments from 43.0 mm to 47.5 mm.

[0071] Figure 6 The results of drop tests were presented for a can body 10 of an embodiment and a comparative example, which was formed with an aluminum alloy thickness of 0.22 mm, a can height of 155.3 mm, a grounding diameter of 45.4 mm, and an outer diameter of 57.2 mm, and whose recess depth was changed by 0.5 mm in increments from 0.40 to 0.85.

[0072] Figure 5 and Figure 6 In the table shown, for all drop tests of the examples and comparative examples, an aluminum alloy deep-drawn and thinned can was used as the can body 10. The filling material of the can body 10 was at a liquid temperature of 35°C, and the internal pressure in the static state before oscillation was 400 kPa and 500 kPa, respectively. The results are shown in the "Evaluation" column.

[0073] In the "Evaluation" column, after the drop test, if the can is placed individually on a horizontal surface and is in an upright state, a can body 12 tilt angle of less than 2° and no dome 111 is found to have flipped over is evaluated as "Pass" and is marked "○". Conversely, if the can is in an upright state, a can body 12 tilt angle of more than 2°, or even a portion of the dome 111 is found to have flipped over, is evaluated as "Fail" and is marked "×".

[0074] from Figure 5As can be seen from the table, when the grounding diameter is 43.0 mm (Comparative Example 1-1), both the individual drop test and the whole-box drop test for the two types of tanks 10 with internal pressures of 400 kPa and 500 kPa failed. When the grounding diameter is 43.5 mm (Comparative Example 1-2), both the individual drop test and the whole-box drop test for the tank 10 with an internal pressure of 500 kPa failed. In addition, when the grounding diameter is 47.5 mm (Comparative Example 1-3), only in the whole-box drop test with an internal pressure of 400 kPa did the dome 111 not deform; all other tests failed.

[0075] Conversely, when the grounding diameter is 44.0 mm or more and 47.0 mm or less (Examples 1-1 to Examples 1-7), the individual drop test and the whole tank drop test performed on the two types of tanks 10 with internal pressure of 400 kPa and 500 kPa are qualified.

[0076] In addition, from Figure 6 As can be seen from the table, when the indentation depth is 0.40 mm (Comparative Example 2-1), both the individual drop test and the whole-box drop test performed on the two types of tanks 10 with internal pressures of 400 kPa and 500 kPa failed. When the indentation depth is 0.45 mm (Comparative Example 2-2), only the individual drop test at an internal pressure of 400 kPa passed; all other tests failed. When the indentation depth is 0.85 mm (Comparative Example 2-3), both the individual drop test and the whole-box drop test performed on the two types of tanks 10 with internal pressures of 400 kPa and 500 kPa failed.

[0077] Conversely, when the recess depth is between 0.50 mm and 0.80 mm (Examples 2-1 to 2-7), the individual drop test and the whole tank drop test performed on the two types of tanks 10 with internal pressures of 400 kPa and 500 kPa are both qualified.

[0078] As described above, according to this embodiment, the shape and size of the can are optimized, and the bottom of the can 11 is reshaped to make the recess depth 0.5 mm to 0.8 mm and the grounding diameter φ44.0 mm to 47.0 mm. As a result, the can 10 can ensure both the predetermined filling amount of the contents and the pressure resistance and drop strength.

Claims

1. A tank body, a bottomed cylindrical aluminum alloy tank body, comprising: Bottom of the can; A cylindrical can body extending from the outer periphery of the can bottom along the can axis, centered on the can axis; The tank bottom includes: a rounded top located at the center of the tank bottom; and an annular protrusion that continuously protrudes from the outer periphery of the rounded top along the tank axis toward the outer side of the tank body. The annular protrusion is continuously provided on the top of the round and includes a recess having a curved surface protruding radially outward from the tank body. The grounding part that supports the tank body; From the grounding portion to the inner peripheral wall portion of the recess; The outer diameter of the tank body is in the range of 50mm to 59mm. The height of the can from the grounding part to the upper end of the can body is in the range of 120mm to 190mm. On the longitudinal section including the tank shaft, The recess depth is between 0.5mm and 0.9mm. Grounding diameter is Above 44.0mm and below 47.0mm, Here, the recess depth is the radial distance between the portion of the outer surface of the can body on the recessed part that is furthest from the can axis, and the portion of the outer surface of the can body on the grounding part that is closest to the can axis; the grounding diameter is the diameter of the most protruding part of the grounding part in the direction of the can axis downwards. The thickness of the aluminum alloy at the dome on the can shaft is 0.18–0.26 mm. On the grounding portion, a first convex curved surface near the can shaft and a second convex curved surface away from the can shaft are formed at the most protruding part of the grounding portion in the direction of the can shaft. On the longitudinal section, The radius of curvature of the first convex curved surface is 0.4 mm to 0.7 mm, and the radius of curvature of the second convex curved surface is 1.6 mm to 2.2 mm. The inner peripheral wall has an inclined surface, the angle between the inclined surface and the tank axis being more than 15° and less than 30°.

2. The tank body according to claim 1, wherein the radius of curvature of the recess is 0.3 mm or more and 1.2 mm or less. The distance from the most protruding part on the grounding part towards the lower side in the direction of the can axis to the part on the outer surface of the recessed part that is farthest from the can axis in the direction of the can axis is more than 1 mm and less than 4 mm.

3. The tank body according to claim 1 or 2, wherein the dome includes a tapered portion with one end continuous with the outer peripheral edge of the dome and the other end continuous with the recess.

4. The tank body according to claim 1 or 2, wherein the dome comprises: A first dome recessed into the inner side of the tank body at the center of the tank bottom along the tank axis; A second dome, which is radially outward from the outer periphery of the first dome, recessed towards the inner side of the tank body, and has a radius of curvature smaller than that of the first dome, is continuously disposed thereon.

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