JP2016047542A - Producing method of can, bottom reforming mechanism, and bottom supporting member used for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve productivity in which a device structure is not complicated, a can subjected to a bottom reform machining may be easily and stably supported while suppressing support load in a can axis direction on the can, a can bottom may be accurately formed, strength may be sufficiently ensured, and producing speed may be increased.SOLUTION: In a bottom reforming step, an opening end part of a can body 1 is supported by a top supporting member, and by a bottom supporting member 14, end part at a can bottom 2 side in the can body 1, end edge 7 on outside of a can 10 along with a can axis direction in annular projecting part 6 at the can bottom 2 and a part along with the can axis direction of an outer peripheral wall 9 providing recessed curve surface on annular projecting part 6 at the can bottom 2 are supported. Thereby, the can 10 is sandwiched toward inside of the can 10 along with the can axis direction, and under a supported state toward inside in a radial direction orthogonal to a can axis, bottom reform machining is carried out onto an inner peripheral wall 8 of the annular projecting part 6 so that a recessed part recessed toward outside in the radial direction is formed on the inner peripheral wall 8.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a technology for accurately and stably bottom reforming (BPR processing) of a can bottom (bottom) in which contents such as beverages are sealed. Specifically, The present invention relates to a manufacturing method, a bottom reforming mechanism, and a bottom support member used therefor.

As a can filled and sealed with contents such as beverages, it has a can body (wall) and a bottom (bottom), and a two-piece can with a can lid wound around the open end of the can body, or a can body There is known a bottle can in which a cap is screwed onto an opening end of the bottle.
Conventionally, for example, as shown in Patent Document 1 below, the bottom of a can has a dome portion recessed toward the inside of the can along the can axis direction, and an outer peripheral edge portion of the dome portion, along the can axis direction. An annular convex portion (counter sink) is formed that protrudes toward the outside of the can and extends along the circumferential direction around the can axis.

In recent years, from the viewpoint of environmental protection such as CO ₂ emission reduction, there is an increasing demand for weight reduction of aluminum cans by reducing raw materials used. Specifically, aiming to reduce the weight of cans of 0.1 g or more (about 1% or more), it is necessary to develop lightweight cans that do not impair pressure strength reduction and productivity and are strong against distribution pinholes. . Even with a reduction of 0.1 g per can, if it can be applied to 18 billion cans per year in the aluminum can market, a significant reduction in environmental impact can be achieved.

In order to reduce the weight of the can, the original plate thickness of the plate material (plate material of the can before molding, hereinafter sometimes referred to as a blank) must be reduced, but if a thin blank is used, the original plate thickness is reduced. The pressure resistance of the maintained can bottom is lowered.
When the pressure-resistant strength is reduced, the annular convex portion at the bottom of the can extends along the can axis direction, for example, as shown in FIG. A so-called bottom growth is generated, which projects toward the outside of the can (below the can) and deforms toward the outside in the radial direction perpendicular to the can axis direction.

  If bottom growth occurs, the height of the can (total length in the can axis direction) is not stable, which may cause problems in production and shipment, which is not preferable. Further, when the internal pressure of the can exceeds the pressure resistance strength, the dome portion at the bottom of the can is reversed and a buckling that protrudes outward in the can axis direction is generated.

As a technique for suppressing such bottom growth and buckling, the inner peripheral wall (inner wall) of the annular convex portion at the bottom of the can is recessed radially outward to increase the strength, so-called bottom reform processing (BPR processing) It has been known.
Specifically, a can having a bottomed cylindrical shape (a can having a dome and an annular protrusion formed on the bottom of the can) that has undergone drawing and ironing (DI processing) while supporting the can in the axial direction and the radial direction. An annular concave portion extending in the circumferential direction around the can axis is formed with respect to the inner peripheral wall of the bottom annular convex portion while being recessed outward in the radial direction.

For example, in Patent Document 1 below, among the end (shoulder) on the can bottom side of the can body and the annular convex portion of the can bottom, the outside of the can along the can axis direction from the end on the can bottom side of the can body (that is, A bottom reforming process is performed by supporting the entire surface of the outer peripheral wall of the concave curved surface that gradually inclines inward in the radial direction toward the lower side of the can by a bottom support member (cup outer peripheral side holder). In Patent Document 1, a mandrel (dome push-down tool) is inserted from the opening end of the can body toward the inside to support the can from the inside.
Further, in the following Patent Document 2, FIG. 6A, the bottom of the can bottom side of the can body, and the outer edge of the can along the can axis direction of the annular convex portion (that is, the lower end edge of the can) of the can bottom It is supported by a support member and bottom reformed.
Further, as a method other than the above, an annular groove having a shape corresponding to the outer end of the can along the axial direction of the can in the annular protrusion is formed in the bottom support member, and the annular protrusion is formed in the annular groove. There is known a technique in which the end portion is inserted to perform a bottom reforming process.

JP-A-9-285832 US Pat. No. 5,704,241

However, the conventional can bottom reforming process has the following problems.
That is, in Patent Document 1, the end portion on the can bottom side of the can body and the entire outer surface of the concave curved outer peripheral wall of the annular convex portion of the can bottom are supported by the bottom support member. In this method, the bottom support member cannot be brought into close contact with the outer peripheral wall having a concave curved surface due to variations in the shape of the bottom of the can (molding error). In addition, in order to make a bottom support member closely_contact | adhere with respect to the outer peripheral wall whole surface, it is possible to increase the support load of the can to a can axial direction, However, In this case, load is applied to can itself or an installation.

Moreover, in patent document 1, since the mandrel is inserted into the can, the stroke of the apparatus becomes long, and the production speed cannot be increased. Furthermore, if the variation in the dimensions of the can supplied from the previous process to the bottom reformer is large, the mandrel cannot be stably inserted into the can, which affects productivity.
Therefore, in order to increase the production speed, it is possible to shorten the stroke of the top support member by using the top support member instead of the mandrel and supporting the opening end of the can body by the top support member. In this case, the problem of instability of support by the above-described bottom support member tends to become more prominent.

Further, in Patent Document 2, when bottom reforming is performed with the inner peripheral wall of the annular convex portion facing outward in the radial direction, a large molding load is applied to the end portion on the bottom side of the can body (lower end portion of the can body). May cause the can to be deformed (dented).
Further, in the method of supporting the can bottom by inserting the outer end of the can along the can axis direction of the annular convex portion into the annular groove described as a method other than the above, variation in the shape of the can bottom (molding error) ), The play is likely to occur between the annular groove and the end portion of the annular convex portion. If there is such a backlash, the can swings (displaces) in the radial direction due to the molding load when the inner peripheral wall of the annular convex portion is pressed toward the outside in the radial direction to perform the bottom reforming process. Accuracy cannot be secured.

  The present invention has been made in view of such circumstances, and can easily perform a bottom reforming can without complicating the device structure and suppressing the supporting load of the can in the can axis direction. , And can be supported stably, thereby giving the desired shape to the can bottom with high accuracy, ensuring sufficient strength, and increasing the production speed, It aims at providing the manufacturing method of the can which can improve productivity, a bottom reforming mechanism, and the bottom support member used for this.

In order to solve such problems and achieve the above object, the present invention proposes the following means.
That is, the method for producing a can according to the present invention includes a bottomed cylindrical can having a can body and a can bottom by squeezing and squeezing a plate material, and the inside of the can along the can axis direction on the can bottom. A dome portion that is recessed toward the outer periphery, and an annular convex portion that is continuous with the outer peripheral edge portion of the dome portion, protrudes toward the outside of the can along the can axis direction, and extends along a circumferential direction around the can axis. A squeezing and squeezing step to form, a bottom support member is brought into contact with the bottom of the can, and a top support member is brought into contact with the opening end of the can body so that the can is moved along the can axis direction of the can. The inner peripheral wall is formed by bottom reforming the inner peripheral wall connected to the dome portion of the annular convex portion in a state of being held inward and supported toward the inner side in the radial direction orthogonal to the can axis. A bottom reformer that forms a recess recessed outward in the radial direction In the bottom reforming step, the bottom support member allows the end of the can bottom side of the can body, and the can bottom of the can along the can axis direction of the annular convex portion of the can bottom. Of the can bottom, the outer end edge and the can bottom are disposed on the radially outer side of the inner peripheral wall of the annular convex portion, and connected to the end of the can bottom on the can bottom side. Part of the outer peripheral wall that forms a concave curved surface that gradually inclines inward in the radial direction from the end of the can bottom side toward the outside of the can along the can axis direction. And is supported.
Further, the present invention provides a bottomed cylindrical can having a can body and a can bottom, a dome portion recessed toward the inside of the can along the can axis direction, and an outer peripheral edge portion of the dome portion. And an annular convex portion that protrudes toward the outside of the can along the can axis direction and extends along a circumferential direction around the can axis, and is connected to the dome portion of the annular convex portion. A bottom reforming mechanism for forming a recess recessed on the inner peripheral wall toward the outside in the radial direction perpendicular to the can axis, the bottom support member approaching and separating from the can bottom and abutting against the can bottom And a top support member that is close to and away from the opening end, and that can come into contact with the opening end, and a convex portion that is close to and away from the inner peripheral wall and can come into contact with the inner peripheral wall. The bottom support member is the can Of the can bottom side of the can, the outer edge of the can along the can axis direction of the annular convex portion of the can bottom, and the inner peripheral wall of the annular convex portion of the can bottom The outer end of the can body is connected to the end portion on the can bottom side of the can body, and from the end portion on the can bottom side of the can body to the outside of the can along the can axis direction. The outer peripheral wall that forms a concave curved surface that gradually inclines toward the inside in the radial direction as it goes, and is configured to support a portion along the can axis direction, by the bottom support member and the top support member In the state where the can is sandwiched toward the inside of the can along the axial direction of the can and is supported toward the inside of the radial direction, the convex portion faces the inner peripheral wall toward the outside in the radial direction. The concave portion is formed by pressing to form the concave portion.
The bottom support member of the present invention is used for the above-described bottom reforming mechanism.

According to the can manufacturing method, the bottom reforming mechanism and the bottom supporting member used therefor according to the present invention, in the bottom reforming step, the bottom supporting member is brought into contact with the bottom of the can and the top end is supported at the opening end of the can body. The inner peripheral wall of the annular convex portion is bottom-reformed with the member in contact with the can being sandwiched toward the inner side of the can along the axial direction of the can and supported toward the inner side of the radial direction. Is molded.
In this way, the top support member is brought into contact with the opening end of the can body so as to support the can, so that the stroke of the top support member relative to the can can be kept small, and the production speed can be increased. .

  Further, the bottom support member is brought into contact with the bottom of the can, and the top support member is brought into contact with the opening end of the can body so that the can is sandwiched from both sides in the can axis direction and is also supported from the radial direction. In this state, the inner peripheral wall of the annular convex portion is bottom reformed to form the concave portion, so that the position of the concave portion in the can axis direction is stably determined with high accuracy. That is, for example, even when the recess is formed in an annular shape extending over the entire circumference in the circumferential direction with respect to the inner peripheral wall, the position of the recess in the can axis direction does not change over the entire circumference of the inner peripheral wall. Therefore, it is possible to stably secure the expected strength at the bottom of the can.

The bottom support member includes an end on the can bottom side of the can body, an outer edge (nose) of the can along the can axis direction in the annular convex portion of the can bottom, and an annular convex portion of the can bottom. The outer peripheral wall, which is disposed on the radially outer side of the inner peripheral wall in the section and has a concave curved surface shape, supports a part along the can axis direction.
In other words, in the longitudinal sectional view of the can along the can axis direction, the bottom support member supports the can at three points in the radial direction, the can axis direction, and the direction in which these can be combined. Is obtained.

That is, the bottom support member abuts the end of the can body on the bottom side of the can and supports the end toward the inner side in the radial direction. Is prevented.
Further, the bottom support member abuts on the outer edge of the can along the can axis direction in the annular convex portion and supports the end edge toward the inside of the can along the can axis direction. It is possible to prevent the direction from swinging.
Further, the bottom support member abuts on the outer peripheral wall of the annular convex portion and supports the outer peripheral wall toward the inner side in the radial direction and toward the inner side of the can along the can axis direction. The effect is obtained more remarkably.

In addition, when the bottom support member is in contact with the outer peripheral wall of the annular convex portion, the inner peripheral wall of the annular convex portion is subjected to bottom reform processing toward the outer side in the radial direction, the end portion on the can bottom side of the can body The forming load acting in the radial direction is dispersed, and the deformation of the end portion is suppressed.
In addition, the bottom support member abuts on the outer peripheral wall of the annular protrusion, so that the support load of the can in the can axis direction acting on the outer edge of the can along the can axis direction in the annular protrusion is dispersed. Thus, deformation of the edge is suppressed.

Here, since the bottom support member abuts against the outer peripheral wall is a part along the can axis direction of the outer peripheral wall, specifically, the bottom support member is in the can axis direction with respect to the outer peripheral wall. In a part along the line, it is easy to make line contact over the entire circumference.
As a result, even if there is a variation in the can bottom shape (molding error) in the previous process of the bottom reforming process, the bottom reforming process is performed with respect to the concave curved outer peripheral wall of the annular convex part. The support member can be reliably brought into contact with each other, and the above-described effects can be stably achieved.

In addition, since the bottom support member can be stably brought into contact with the outer peripheral wall of the annular convex portion, the can support load in the can shaft direction can be suppressed to a low load. Accordingly, the load on the can itself and the equipment can be reduced.
Furthermore, the above-described excellent operational effects can be obtained by a simple configuration in which the bottom support member is brought into contact with the outer peripheral wall of the annular convex portion at a part in the can axis direction, thereby complicating the structure of the apparatus. There is nothing.

  As described above, according to the present invention, it is possible to easily and stably support a can for bottom remodeling without complicating the device structure and suppressing the support load of the can in the can axis direction. As a result, the desired shape of the bottom of the can can be accurately applied to the expected position, sufficient strength can be ensured, the production speed can be increased, and the productivity can be improved.

  Further, in the method for producing a can of the present invention, between the squeezing and squeezing step and the bottom reforming step, the opening end portion of the can body is necked, and more than a portion other than the opening end portion, A neck portion that gradually or gradually decreases in diameter toward the outside of the can along the can axis direction, and a flange planned portion that is positioned outside the can along the can axis direction with respect to the neck portion are formed. And in the bottom reforming step, the top support member is brought into contact with the neck portion, and as a subsequent step of the bottom reforming step, the flange portion is flanged to form a flange portion. It is good also as providing a flanging process.

According to the above configuration, in the necking step, the opening end portion of the can body is necked, and the diameter gradually decreases or gradually decreases toward the outside of the can along the can axis direction from the portion other than the opening end portion. The neck part to perform and the flange pre-scheduled part located in the outer side of the can along a can axial direction rather than a neck part are shape | molded.
And, in the bottom reforming step, the bottom support member is brought into contact with the bottom of the can, and the top support member is brought into contact with the neck portion to sandwich the can toward the inside of the can along the can axis direction, and In a state where it is supported toward the inside in the radial direction, the inner peripheral wall of the annular convex portion is bottom-reformed to form a concave portion.
Thereafter, in the flanging step, the flange portion is flanged to form the flange portion.

  That is, since the top support member supports the neck portion, not the planned flange portion, in the opening end portion of the can body, there is no possibility of deforming the planned flange portion. In other words, since the pre-deformed flange portion without deformation is subsequently formed into the flange portion, the forming accuracy of the flange portion is improved, and the sealing performance is ensured when winding with the can lid. Even if the planned flange part is deformed at the time of bottom reforming, the flange part is shaped by flanging after that, and the sealing performance at the time of winding is also secured. It becomes possible to do.

  Further, since the neck portion is formed in a stepwise or gradually reduced diameter from the portion other than the opening end portion of the can body toward the outside of the can along the can axis direction, the top support member is formed on the neck portion. , The top support member can support the can toward the bottom of the can along the can axis direction and can also support the can toward the inside in the radial direction. Therefore, the can can be supported easily and stably without complicating the structure of the apparatus.

  Further, since the top support member abuts against the neck portion (outer surface of the can body), not to the end edge (open end surface) of the opening end portion of the can body, there is a possibility that the top support member is worn out early. Therefore, the frequency of maintenance and parts replacement can be kept low.

  Further, in the can manufacturing method of the present invention, in the bottom reforming step, a molding roller is brought into contact with the inner peripheral wall, and the inner peripheral wall is rolled over the entire circumference in the circumferential direction around the can axis. It is good also as shape | molding the said cyclic | annular recessed part extended over the perimeter of the said circumferential direction in the said inner peripheral wall.

  In this case, since the recess is bottom-reformed over the entire circumference of the inner peripheral wall of the annular protrusion, the strength of the can bottom can be sufficiently increased.

  Further, in the bottom reforming mechanism of the present invention, the bottom support member includes a can body support portion that contacts an end portion on the can bottom side of the can body, and the can shaft at the annular convex portion of the can bottom. A nose support portion that contacts the outer edge of the can along the direction, and an outer peripheral wall support portion that contacts a portion of the annular convex portion along the can axis direction of the outer peripheral wall of the can bottom, Among the can body support portion, the nose support portion, and the outer peripheral wall support portion, one may be separated from the other two, or these three may be separated from each other. Good.

  According to the above configuration, in the bottom support member, one of the can body support portion, the nose support portion, and the outer peripheral wall support portion is separated from the other two support portions, or these 3 Since the two support parts are separated from each other, various cans can be obtained by replacing any one or more of these can body support parts, nose support parts, and outer peripheral wall support parts with different shapes. It can easily cope with the shape.

  According to the can manufacturing method, the bottom reforming mechanism, and the bottom supporting member used therefor according to the present invention, the bottom reforming process is performed without complicating the device structure and suppressing the supporting load of the can in the can axis direction. The can can be supported easily and stably, so that the desired shape of the bottom of the can can be accurately applied to the expected position, sufficient strength can be secured, and the production speed can be increased. It can be accelerated and productivity can be improved.

It is a longitudinal cross-sectional view which shows an example of the can manufactured by the manufacturing method of the can which concerns on one Embodiment of this invention. It is a figure explaining the manufacturing method of the can concerning one embodiment of the present invention. It is a flowchart explaining the manufacturing method of the can which concerns on one Embodiment of this invention. It is a longitudinal cross-sectional view which shows the bottom reform mechanism and can which concern on one Embodiment of this invention, and represents the state before supporting a can with a bottom support member and a top support member. It is a longitudinal cross-sectional view which shows the bottom reform mechanism and can which concern on one Embodiment of this invention, and represents the state which supported the can by the bottom support member and the top support member. It is a figure which expands and shows the A section of FIG. It is a figure which expands and shows the B section of FIG. It is a longitudinal cross-sectional view which shows the other example of the top support member and can of the bottom reform mechanism which concerns on one Embodiment of this invention, and represents the state before supporting a can with a top support member. It is a longitudinal cross-sectional view which shows the other example of the top support member and can of the bottom reform mechanism which concerns on one Embodiment of this invention, and represents the state which supported the can by the top support member.

Hereinafter, with reference to the drawings, a can 10, a manufacturing method thereof, and a bottom reforming mechanism 30 according to an embodiment of the present invention will be described.
The can 10 of the present embodiment is a two-piece can that is filled and sealed with contents such as beverages.
As shown in FIG. 1, a can 10 has a bottomed cylinder having a can body (wall; sometimes referred to as a body portion) 1 and a can bottom (bottom; sometimes referred to as a bottom portion) 2. The can is sealed by winding a can lid (not shown) around the open end of the can body 1 with the contents filled therein.

The can body 1 and the can bottom 2 of the can 10 are arranged coaxially with each other. In this specification, the common shaft is referred to as a can shaft O. Of the can axis O direction, the direction from the outside to the inside of the can 10 is referred to as the inside of the can 10 along the can axis O direction. Of the can axis O direction, the direction from the inside of the can 10 to the outside can It is called the outside of the can 10 along the axis O direction. In the present embodiment, in order to clearly describe the components of the can 10, the can bottom 2 side along the can axis O direction is referred to as a lower side, and the opposite side to the can bottom 2 along the can axis O direction ( The opening end side of the can body 1 may be referred to as the upper side.
A direction perpendicular to the can axis O is referred to as a radial direction. Of the radial directions, a direction approaching the can axis O is referred to as an inner side in the radial direction, and a direction away from the can axis O is referred to as an outer side in the radial direction. Further, a direction around the can axis O is referred to as a circumferential direction.

In addition, the terms “concave”, “convex”, “concave”, and “protrude” as used in this specification are irregular shapes on the outer surface of the can 10 (surface exposed to the outside of the can 10) unless otherwise specified. Represents.
Further, in the longitudinal sectional view shown in FIG. 1, “curve (concave curve / convex curve)”, “straight line”, and “tangent” used for explanation of each component are the longitudinal section unless otherwise specified. Various lines on the outer surface of the can 10 are represented by visual observation.

In FIG. 1, the upper end of the can body 1 of the can 10 of the present embodiment is an open end that opens to the outside of the can 10. The contents are filled into the can 10 through this open end. The can 10 shown in FIG. 1 has undergone a flanging step in the can manufacturing method described later, and a neck portion 3 having a diameter reduced upward and a neck portion at the opening end of the can body 1. 3 and a flange portion 4 whose diameter is increased upward is formed.
The lower end of the can body 1 is closed by the can bottom 2. The outer diameter of the can body 1 is, for example, 65 to 67 mm.

  The can bottom 2 is located on the can axis O and is continuous with the dome part 5 recessed upward (inside the can 10 along the direction of the can axis O) and the outer peripheral edge part of the dome part 5, and below (can And an annular convex portion (counter sink) 6 that protrudes toward the outer side of the can 10 along the axis O direction and extends along the circumferential direction.

  When the can 10 is placed in an upright posture (a posture in which the opening end of the can body 1 faces upward, see FIG. 1), the annular convex portion 6 is placed on the ground surface (mounting surface). Further, a grounding part (nose) 7 in contact with the grounding surface, an inner peripheral wall (inner wall) 8 located on the radially inner side (right side in FIG. 1) of the grounding part 7, and a radially outer side of the grounding part 7 And an outer peripheral wall (outer wall) 9 located on the left side in FIG.

  The grounding portion 7 is located at the lower end edge of the annular convex portion 6 (the outer edge of the can 10 along the can axis O direction in the annular convex portion 6). Specifically, the grounding portion 7 protrudes downward most in the can bottom 2 and has an annular shape extending along the circumferential direction.

  The outer peripheral wall 9 is connected to the lower end of the can body 1 (the end of the can body 1 on the can bottom 2 side), and is disposed adjacent to the radially outer side of the inner peripheral wall 8 via the grounding portion 7. . The outer peripheral wall 9 is gradually inclined inward in the radial direction from the lower end of the can body 1 toward the lower side (outside of the can 10 along the can axis O direction), and has a concave curved surface shape.

Specifically, the outer peripheral wall 9 has an upper end connected to the lower end of the can body 1 and has a convex curved shape, and a lower end connected to the inner peripheral wall 8 and has a convex curved shape, An intermediate portion of a relatively wide region located between the lower portion and the lower end portion has a concave curved surface shape, and the outer peripheral wall 9 as a whole has a concave curved surface shape.
Further, the upper end of the outer peripheral wall 9 and the lower end of the can body 1, the lower end of the outer peripheral wall 9 (radially inner end), and the lower end of the inner peripheral wall 8 (radially outer end) are shown in FIG. In the longitudinal cross-sectional view of the can 10 along the direction of the can axis O shown in FIG.

  In the longitudinal sectional view shown in FIG. 1, the upper end portion of the outer peripheral wall 9 is formed in a curved shape (convex curve) that protrudes radially outward and downward (that is, toward the outer diameter side and obliquely downward). ing. Of the peripheral wall of the can 10, with reference to a virtual plane (not shown) passing through the center of the radius of curvature of the convex curve and perpendicular to the can axis O, the lower side of the virtual plane is the can bottom 2, and the upper side is the can body It is set to 1.

In the longitudinal sectional view, the lower end portion of the outer peripheral wall 9 has a curved shape that is convex toward the outer diameter side and obliquely downward.
In the longitudinal cross-sectional view of FIG. 1, the intermediate portion located between the upper end portion and the lower end portion of the outer peripheral wall 9 has a curved shape that is recessed radially inward and upward (that is, toward the inner diameter side and obliquely upward). (Concave curve).

In the longitudinal cross-sectional view of FIG. 1, the upper end portion and the intermediate portion, and the intermediate portion and the lower end portion of the outer peripheral wall 9 are smoothly connected so as to have a common tangent at the connecting portion.
Moreover, the outer surface shape of the can 10 in this longitudinal sectional view may not be formed by a single arc, and the intermediate portion may be formed by combining a plurality of arcs having different curvature radii, for example. Moreover, you may have a linear part between some circular arcs.

  The inner peripheral wall 8 is connected to the radially outer end (outer peripheral edge) of the dome portion 5, and is disposed adjacent to the outer peripheral wall 9 in the radial direction via the grounding portion 7. In the longitudinal sectional view shown in FIG. 1, the inner peripheral wall 8 is erected from the grounding portion 7 so as to be along the can axis O direction as a whole.

The inner peripheral wall 8 has a lower curved portion (lower half) connected to the outer peripheral wall 9 and has a convex curved surface, and an upper portion (upper half) connected to the outer peripheral edge of the dome portion 5 and a concave curved surface. It is the recessed part 11 which makes a shape. The recess 11 has an annular shape extending over the entire circumference in the inner peripheral wall 8 and is formed by a bottom reforming step in a can manufacturing method described later.
Further, the upper end portion (concave portion 11) of the inner peripheral wall 8 and the lower end portion (outer peripheral edge portion) of the dome portion 5 are smoothly connected so as to have a common tangent at the connection portion in the longitudinal sectional view of FIG. ing.

In the longitudinal sectional view shown in FIG. 1, the lower part of the inner peripheral wall 8 has a curved shape that protrudes radially inward.
Moreover, in this longitudinal cross-sectional view, the upper part (recess 11) of the inner peripheral wall 8 has a curved shape that is recessed outward in the radial direction.
In the longitudinal sectional view of FIG. 1, the upper part and the lower part of the inner peripheral wall 8 are smoothly connected so as to have a common tangent line at the connection part.

Next, with reference to FIGS. 1-3, an example of the process of manufacturing the bottomed cylindrical can 10 from the board | plate material (blank) W of aluminum alloy material is demonstrated.
As shown in FIG. 3, the can 10 according to the present embodiment includes a plate blanking process, a drawing and ironing process (including a cupping process and a DI process), a trimming process, a printing process, a painting process, a necking process, a bottom reforming process, and The can is made through the flanging process in this order.

[Sheet punching process]
An ingot made of an Al alloy material is subjected to hot rolling, cold rolling and annealing to form an intermediate plate having a predetermined thickness, and then the intermediate plate is subjected to cold finish rolling to obtain a final thickness. A material is prepared, the rolled material is punched, and a disk-shaped plate material (blank) W is formed (punched) as shown in FIG.

  As the Al alloy material of the plate material W, for example, by weight% (hereinafter the same), Si ≦ 0.4%, Fe ≦ 0.5%, Cu: 0.05 to 0.3%, Mn: 1.0 -1.5%, Mg: 0.8 to 1.3%, Zn ≦ 0.25%, and the balance of Al and inevitable impurities can be used.

[Squeezing and ironing process]
Next, as shown in FIG. 2B, the plate material W is drawn by a cupping press to form a cup-shaped body W1.
Further, as shown in FIG. 2 (c), the cup-shaped body W1 is redrawn and ironed by a DI processing apparatus to form a bottomed cylindrical can W2.
That is, the “drawing and ironing process (drawing and ironing process)” in this specification includes a cupping process (cupping process) and a DI process (DI process).

  A DI processing apparatus used for redrawing ironing is a single redrawing die having a circular through hole for redrawing and a plurality of pieces having a circular through hole arranged coaxially with the redrawing die. (For example, 3) ironing dies (coiling dies) and coaxial with the ironing dies, and can be fitted inside the through holes of each of the above ironing dies, and are movable in the axial direction of the die. A cylindrical punch sleeve, and a cylindrical cup holder sleeve fitted to the outside of the punch sleeve.

In the redrawing process by the DI processing apparatus, the cup-shaped body W1 is arranged between the punch sleeve and the redrawing die, the cup holder sleeve and the punch sleeve are advanced, and the cup holder sleeve is cupped on the end face of the redrawing die. The punch sleeve pushes the cup-shaped body W1 into the through-hole of the redraw die while pressing the bottom surface of the shaped body W1 to perform the cup pressing operation.
As a result, a redrawn cup-like body (not shown) having a predetermined inner diameter is formed. Subsequently, the redrawn cup-shaped body is passed through a plurality of ironing dies one after another and gradually squeezed to squeeze the peripheral wall of the cup-shaped body and extend the peripheral wall to increase the peripheral wall height. At the same time, the wall thickness is reduced to form a bottomed cylindrical can W2.

After the ironing process has been completed, the bottom of the can W2 is formed in a dome shape, for example, by the punch sleeve pushing out further forward and pressing the bottom against the bottom molding die.
As described above, the can W2 is cold-worked and hardened by squeezing the peripheral wall as described above.

The opening end W2a of the drawn and ironed can W2 is formed in an uneven shape (uneven wave shape) that undulates in the direction of the can axis O toward the circumferential direction. In addition, this uneven | corrugated wave shape is provided from the time of shape | molding the board | plate material W in the cup-shaped body W1. Of the edge that forms the irregular wave shape of the opening end W2a, a portion (convex portion) that is a peak protruding upward is an ear. A plurality of ears are formed along the circumferential direction at the opening end W2a. These ears are caused, for example, by the crystallographic anisotropy of aluminum alloys.
In this way, the can body 1 that forms the body of the can, the can bottom 2 that forms the bottom of the can, and includes the dome 5 and the annular protrusion 6 (however, the recess 11 is not formed), Is formed.

[Trimming process]
Next, the opening end W2a of the can W2 is trimmed.
That is, since the opening end W2a of the can W2 formed by the DI processing apparatus has an ear and is uneven in height, by cutting and trimming the opening end W2a of the can W2, As shown in FIG. 2D, the height of the peripheral wall along the can axis O direction at the opening end W3a of the can body 1 is made uniform over the entire circumference.
Thereby, the can W3 after trimming which does not have an ear | edge in the opening edge part W3a of the can body 1 (ear was cut off) is obtained.

[Printing process, painting process]
After cleaning the can W3 and removing the lubricating oil, etc., it is subjected to a surface treatment and dried, followed by outer surface printing and outer surface coating, and then inner surface coating.
For example, the outer surface coating is performed by printing and coating the outer surface of the can body 1 of the can W3 using a polyester-based paint, and the can W3 subjected to the outer surface printing and outer surface coating is heated and dried in an oven. When drying by heating in the oven, a conveyance pin extending in a substantially horizontal direction is inserted from the opening end W3a of the can body 1 into the inside, and the conveyance pin supports the can W3, It is moved by a drive mechanism including a chain, a motor, and the like. In addition, the inner surface is coated on the inner surface of the can W3 using, for example, an epoxy-based paint, and then heated and dried in an oven.

[Necking process]
Next, the can W3 is necked.
That is, the opening end W3a of the can body 1 shown in FIG. 2 (d) is necked, and as shown in the can 10 of FIGS. 4, 6 and 8, other than the opening end of the can body 1 From the neck part 3 and the neck part 3 that gradually reduce the diameter stepwise or gradually toward the outside of the can 10 along the can axis O direction (above the can 10) rather than the site (outermost diameter part of the can 10). Also, the pre-flange portion 12 located outside the can W3 along the can axis O direction is formed into a can 10.

Specifically, in the example shown in FIGS. 4 and 6, the neck portion 3 that is gradually reduced in diameter toward the outside of the can 10 along the can axis O direction is formed by necking, and the neck portion is formed. 3, a plurality of step portions 13a to 13d arranged in the can axis O direction are formed.
In the longitudinal sectional view of the can 10 shown in FIG. 6, the plurality of step portions 13 a to 13 d of the neck portion 3 are curves that are convex outward and upward in the radial direction (that is, toward the outer diameter side and obliquely upward). It is formed in a shape (convex curve). Further, the outer diameters of the step portions 13a to 13d are gradually reduced from the lowermost step portion 13a toward the uppermost step portion 13d.
In the illustrated example, a total of four step portions 13a to 13d of the neck portion 3 are formed, but the number of step portions is not limited to this, and may be three or less, or 5 There may be more than one.

In the example shown in FIG. 8, in the necking step, the neck portion 3 that gradually decreases in diameter toward the outside of the can 10 along the direction of the can axis O is formed, and the neck portion 3 has a plurality of steps. The parts 13a to 13d are not formed.
In the longitudinal sectional view shown in FIG. 8, the neck portion 3 is smooth so as to have a common tangent at each connecting portion with respect to the portion other than the opening end portion of the can body 1 and the flange preliminarily portion 12. It is connected to.
Further, the planned flange portion 12 is formed in a cylindrical shape.

[Bottom reform process]
Next, the bottom reforming process 30 is performed on the can bottom 2 of the can 10 using the bottom reforming mechanism 30. Here, the bottom reforming process will be mainly described, and the configuration of the bottom reforming mechanism 30 will be described later.
As shown in FIGS. 4 to 9, in the bottom reforming process, the bottom support member 14 is brought into contact with the can bottom 2, and the top support member 15 is attached to the neck portion 3 positioned at the opening end of the can body 1. In a state where the can 10 is held in contact with the inner side of the can 10 along the direction of the can axis O and supported toward the inner side of the radial direction orthogonal to the can axis O, the annular protrusion 6 Of these, bottom reforming is performed on the inner peripheral wall 8 connected to the dome portion 5, and a concave portion 11 (see FIG. 1) that is recessed outward in the radial direction is formed on the inner peripheral wall 8.

First, a method for supporting the neck portion 3 by the top support member 15 will be described.
As shown in FIGS. 4 to 6, when a plurality of step portions 13 a to 13 d arranged in the can axis O direction are formed on the neck portion 3 of the can body 1, a plurality of step portions are formed in the bottom reforming process. The top support member 15 is brought into contact with any one of the step portions 13a to 13d.
More specifically, as shown in FIG. 6, the top support member 15 is arranged on the outermost side of the can 10 along the can axis O direction (the uppermost portion of the can 10) among the plurality of step portions 13 a to 13 d of the neck portion 3. ) Is brought into contact with any one of the step portions 13a to 13c other than the step portion 13d. Alternatively, the top support member 15 is a step other than the step portion 13a located on the innermost side of the can 10 along the can axis O direction (most below the can 10) among the plurality of step portions 13a to 13d of the neck portion 3. The parts 13b to 13d are brought into contact with each other.

  In the present embodiment, in FIG. 6, the top support member 15 is brought into contact with the step portions 13 b and 13 c excluding the step portion 13 d and the step portion 13 a among the plurality of step portions 13 a to 13 d of the neck portion 3. That is, among the plurality of step portions 13 a to 13 d of the neck portion 3, the step portion 13 b adjacent to the upper portion of the step portion 13 a positioned below the can 10 (that is, the second step portion 13 b counted from the bottom), or The top support member 15 is brought into contact with the step 13c adjacent to the upper side of the step 13b (that is, the third step 13c counted from the bottom).

Next, a method for supporting the can bottom 2 with the bottom support member 14 will be described.
As shown in FIGS. 4, 5, and 7, in the bottom reforming step, the bottom support member 14 causes the end of the can body 1 on the can bottom 2 side (the lower end portion of the can body 1) and the can bottom 2 to move. Among them, the outer edge of the can 10 along the can axis O direction in the annular convex portion 6 (that is, the grounding portion 7) and the can bottom 2 along the can axis O direction of the outer peripheral wall 9 in the annular convex portion 6. Part and support.

  Specifically, in FIG. 7, the bottom support member 14 supports the lower end portion of the can body 1 toward the inside in the radial direction (downward in FIG. 7), and the grounding portion 7 of the annular convex portion 6 is positioned upward. (Left side in FIG. 7), and a part of the outer peripheral wall 9 of the annular convex portion 6 (in the illustrated example, the central portion of the outer peripheral wall 9 along the can axis O direction) is radially It supports toward the inside and upward. More specifically, the part of the outer peripheral wall 9 of the annular convex part 6 is a part of the outer peripheral wall 9 in an intermediate part located between the upper end part and the lower end part.

Next, a method for forming the concave portion 11 on the inner peripheral wall 8 of the annular convex portion 6 will be described.
In the bottom reforming process, in FIG. 5, the link is carried out with the top support member 15 and the bottom support member 14 supporting the can 10 from both sides along the can axis O direction and radially inward as described above. The forming roller 16 is moved in the radial direction with respect to the can bottom 2 by using the mechanism 56 to bring the forming roller 16 into contact with the inner peripheral wall 8 and roll on the inner peripheral wall 8 over the entire circumference. Thus, an annular recess 11 extending over the entire circumference in the circumferential direction is formed on the inner peripheral wall 8.

[Flanging process]
Next, the flanged portion 12 shown in FIG. 6 and positioned at the opening end of the can body 1 is flanged to form the flange portion 4 shown in FIG.
In the flanging step of the present embodiment, the plurality of stepped portions 13a to 13d of the neck portion 3 are moved from a portion other than the opening end portion of the can body 1 (the outermost diameter portion of the can body 1) by spin flow molding. The taper surface is gradually reshaped (reformed) toward the outside of the can 10 along the can axis O direction (above the can 10), and the flange portion 12 is formed into the flange portion 4. Specifically, the opening end portion is flanged so that the shapes of the neck portion 3 and the flange portion 4 after molding become the shape of the opening end portion of the can 10 shown in FIG.
However, the present invention is not limited to this, and the plurality of stepped portions 13a to 13d of the neck portion 3 may be left as they are as the final appearance shape of the can 10 without being reshaped into the tapered surface. Good.

  In this way, the can 10 is manufactured and conveyed to the subsequent process of the flanging process. In this post-process, the inside of the can 10 is filled with contents such as a beverage, the can lid is wound around the flange portion 4, and the can 10 is sealed.

Next, the configuration of the bottom reforming mechanism 30 of the present embodiment will be described.
The bottom reforming mechanism 30 performs the bottom reforming process on the can bottom 2 of the can 10 in which the neck portion 3 and the flange planned portion 12 are formed at the opening end portion of the can body 1 through the above-described necking process. And constitutes a part (main part) of a bottom reforming apparatus (not shown).
Of the bottom reforming apparatus, the structure other than the bottom reforming mechanism 30 described in the present embodiment is the same as the can bottom remolding apparatus described in, for example, the above-mentioned Patent Document 2 (US Pat. No. 5,704,241). Since the structure can be used, the description thereof is omitted in the present embodiment.

The bottom reforming mechanism 30 is for forming the concave portion 11 that is recessed outward in the radial direction on the inner peripheral wall 8 of the annular convex portion 6 in the can bottom 2.
As shown in FIGS. 4 to 9, the bottom reforming mechanism 30 is moved toward and away from the can bottom 2, and can be brought into contact with the can bottom 2 and the opening end of the can body 1. A top support member 15 that can approach and separate from the neck portion 3 located at the opening end portion, and a convex portion 17 that can approach and separate from the inner peripheral wall 8 and can contact the inner peripheral wall 8. And a forming roller (forming member) 16 having the following.
In addition, each center axis | shaft of the bottom support member 14 and the top support member 15 is coaxially arrange | positioned at the can axis | shaft O of the can 10 to be bottom-reformed.

The bottom support member 14 is located on the outer side of the can 10 along the direction of the can axis O of the annular convex portion 6 of the can bottom 1 and the end portion on the can bottom 2 side of the can body 1 (the lower end portion of the can body 1). The end edge (that is, the grounding portion 7) and a part of the can bottom 2 along the can axis O direction of the outer peripheral wall 9 of the annular convex portion 6 are supported.
Specifically, as shown in FIGS. 4, 5, and 7, the bottom support member 14 is a can body support that comes into contact with an end of the can body 1 on the can bottom 2 side (lower end portion of the can body 1). Of the can bottom 2, the nose support portion 19 that abuts the outer edge (grounding portion 7) of the can 10 along the can axis O direction of the annular protrusion 6 of the can bottom 2 and the can bottom 2 of the can bottom 2. And an outer peripheral wall support portion 20 that abuts a part of the outer peripheral wall 9 of the convex portion 6 along the can axis O direction.

The can body support portion 18 has a cylindrical shape, and the lower end portion of the can body 1 is fitted into the peripheral wall thereof.
The nose support portion 19 has a ring plate shape that protrudes radially inward from the inner peripheral surface of the cylindrical body 22 and extends along the circumferential direction, and an end surface facing the can bottom 2 side has a bottom support. It is formed in a planar shape perpendicular to the central axis (can axis O) of the member 14, and the end surface abuts on the grounding portion 7.
The outer peripheral wall support portion 20 is located at the upper end portion of the cylindrical body 22 and has a ring shape, and is between the can body support portion 18 and the nose support portion 19 (specifically, the center of these 18, 19). Between the axial directions and between the radial directions perpendicular to the central axis). The surface facing the top support member 15 side in the central axis direction and the inner side in the radial direction in the outer peripheral wall support portion 20 is a convex curved surface that can come into contact with the outer peripheral wall 9 of the can 10 in part in the can axis O direction. It has a shape.
Of the can body support 18, the nose support 19, and the outer peripheral wall support 20, one (support) is separate from the other two (support), or these 3 The two (support parts) are separated from each other. In the present embodiment, the can body support portion 18, the nose support portion 19 and the outer peripheral wall support portion 20 are formed separately from each other and can be individually replaced in accordance with the shape of the can 10.

As shown in FIGS. 4 to 6, 8, and 9, the top support member 15 has a top tube shape, and a neck support portion 21 that supports the neck portion 3 on the inner peripheral surface of the peripheral wall thereof. Is formed.
As shown in FIGS. 4 to 6, when the top support member 15 supports any of the plurality of step portions 13 a to 13 d in the neck portion 3, the neck support is shown in the longitudinal sectional view shown in FIG. 6. The part 21 is formed in a concave curve shape. Specifically, in the present embodiment, the neck support portion 21 is recessed from the inner peripheral surface of the peripheral wall of the top support member 15 in accordance with the shape of the predetermined step portion among the step portions 13a to 13d, and along the circumferential direction. It is formed in the annular groove part extended.

As shown in FIGS. 8 and 9, when the neck portion 3 is formed in a smooth tapered surface shape having no step portion, the neck support portion 21 of the top support member 15 is Corresponding to the shape of the neck portion 3, it is formed in a tapered surface shape that gradually increases in diameter toward the bottom support member 14 side in the central axis direction.
In this case, an inclination angle θ (see FIG. 9) at which the neck support portion 21 is inclined with respect to the central axis (can axis O) is, for example, 20 to 40 °, and 30 ° in the present embodiment. .

As shown in FIG. 4, the forming roller 16 has an annular shape or a cylindrical shape, is rotatable around the central axis of the forming roller 16, and an outer peripheral edge protruding outward in the radial direction is a convex portion. 17 and so on. The convex portion 17 gradually decreases in width in the central axis direction as it goes outward in the radial direction, and has a curved shape that protrudes outward in the radial direction in the longitudinal sectional view shown in FIG.
Although not particularly illustrated, the molding roller 16 is radially oriented with respect to the can 10 so that its central axis moves between the can axis O and a position radially deviated from the can axis O. Can be moved back and forth.

Next, a schematic configuration of the bottom reforming apparatus and an operation of the bottom reforming mechanism 30 used for the bottom reforming apparatus will be described.
As described above, since the structure other than the bottom reforming mechanism 30 is well known, the bottom reforming apparatus used in the present embodiment is only described for the schematic configuration and the illustration of the apparatus is omitted. .
The bottom reforming device corresponds to a device frame serving as a base of the device, a star wheel (turret) that rotates about the rotation axis with respect to the device frame, and a plurality of pockets formed on the outer periphery of the star wheel. And a bottom reforming mechanism 30 provided.

  The star wheel has a plurality of pockets formed on the outer periphery thereof, and the can 10 is held in the pocket by air adsorption or the like. The star wheel is driven to rotate around its central axis (rotating axis) with respect to the apparatus frame.

Further, a bottom reforming mechanism 30 is provided for each of the plurality of pockets of the star wheel. The plurality of bottom reform mechanisms 30 are rotationally driven around the rotation axis with respect to the apparatus frame together with the star wheel.
Specifically, the top support member 15 and the bottom support member 14 of each bottom reforming mechanism 30 are arranged so as to be coaxial with the can axis O of the can 10 held in each pocket of the star wheel. Yes.

A bottom cam follower is connected to the bottom support member 14 of the bottom reform mechanism 30. The bottom cam follower is engaged with a cam provided on the apparatus frame and extending along the center axis of the star wheel.
The cam constitutes a predetermined track whose position in the central axis direction is displaced as it goes around the central axis of the star wheel. By the bottom cam follower is guided along this trajectory, said bottom cam followers and the bottom support member 14, relative to the can 10 which star wheel is held, the predetermined stroke S _B along the can axis O Move back and forth in range.

Of the bottom reforming mechanism 30, a roller cam follower is coupled to the forming roller 16 via a link mechanism 56 (see FIGS. 4 and 5). The roller cam follower is engaged with a cam (groove cam) provided on the apparatus frame and extending along the center axis of the star wheel.
The cam constitutes a predetermined track whose position in the central axis direction is displaced as it goes around the central axis of the star wheel. By being guided along the track, the roller cam followers, to the can 10 which star wheel is held, it reciprocates along the can axis O in the range of a predetermined stroke S _R. Incidentally, the stroke S _R of the roller cam follower is set larger than the stroke S _B of the bottom cam follower. The forming rollers 16 for connecting the roller cam follower, by the roller cam follower is guided by the cam, with respect to the can 10 which star wheel is held, the predetermined stroke S _B along the can axis O In the range of strokes reciprocated in the range and converted in the radial direction according to the difference (S _R −S _B ) between the strokes S _R and S _B by the link mechanism 56, on the can axis O and from the can axis O It also reciprocates in the radial direction between the biased positions.

The forming roller 16 is connected to a driven gear that meshes with a gear of the device frame (a gear in which a plurality of teeth are arranged around the central axis of the star wheel), and the star wheel rotates about the central axis with respect to the device frame. Thus, the can 10 held by the star wheel is rotated around the can axis O.
That is, the forming roller 16 is rotated (revolved) around the center axis of the star wheel with respect to the apparatus frame, and is rotated (rotated) around the can axis O with respect to the can 10 held in the pocket of the star wheel. )

In the bottom reforming mechanism 30, a top cam follower is connected to the top support member 15. The top cam follower is engaged with a cam provided on the apparatus frame and extending along the center axis of the star wheel.
The cam constitutes a predetermined track whose position in the central axis direction is displaced as it goes around the central axis of the star wheel. By guiding the top cam follower along this track, the top cam follower and the top support member 15 have a predetermined stroke _ST1 along the can axis O direction with respect to the can 10 held by the star wheel. Move back and forth in range. However, after the top support member 15 abuts on the neck portion 3 of the can 10, further forward movement toward the can 10 is restricted by the action of the elastic member, and the actual stroke S _T2 is set to be slightly smaller (about several mm smaller) than the stroke _ST1 . Further, the top support member 15 supports the can 10 while urging the can 10 toward the inside of the can 10 along the can axis O direction by the action of the elastic member.

In such a bottom reforming device and the bottom reforming mechanism 30, the bottom support member 14 and the top support member 15 sandwich the can 10 toward the inside of the can 10 along the can axis O direction, and the radial direction The convex portion 17 of the forming roller 16 presses the inner peripheral wall 8 of the can bottom 2 toward the outer side in the radial direction in a state where the concave portion 11 is formed while being supported inward.
In the present embodiment, the bottom support member 14, the forming roller 16, and the top support member 15 of the bottom reforming mechanism 30 are engaged with each other with respect to the can 10 held by the star wheel by the action of a cam follower and a cam. Although the description has been made using the configuration in which each is moved, the present invention is not limited to this. That is, the bottom support member 14, the forming roller 16, and the top support member 15 of the bottom reforming mechanism 30 are configured to be moved with respect to the can 10 held by the star wheel by a driving means such as an air cylinder or a motor. May be.

According to the manufacturing method of the can 10 according to the present embodiment described above, the bottom reforming mechanism 30 and the bottom support member 14 used therein, the bottom support member 14 is brought into contact with the can bottom 2 in the bottom reforming process, and The top support member 15 is brought into contact with the opening end portion of the can body 1, the can 10 is sandwiched toward the inside of the can 10 along the can axis O direction (the center of the can 10), and radially inward. The inner peripheral wall 8 of the annular convex portion 6 is bottom-reformed and the concave portion 11 is formed in a state where the concave portion 11 is supported.
Thus, since the top support member 15 is brought into contact with the opening end of the can body 1 to support the can 10, the stroke S _T1 (S _T2 ) of the top support member 15 with respect to the can 10 is kept small. Production speed can be increased.

  Further, the bottom support member 14 is brought into contact with the can bottom 2 and the top support member 15 is brought into contact with the opening end portion of the can body 1 so that the can 10 is positioned on both sides in the can axis O direction (up and down of the can 10). Since the inner peripheral wall 8 of the annular convex portion 6 is bottom-reformed and the concave portion 11 is formed while being supported from the radial direction, the position of the concave portion 11 in the can axis O direction is stable and highly accurate. It is decided. That is, for example, when the recess 11 is formed in an annular shape extending over the entire circumference in the circumferential direction with respect to the inner peripheral wall 8 as in this embodiment, the position of the recess 11 in the can axis O direction is the position of the inner peripheral wall 8. There is no change around the entire circumference. Therefore, the expected strength of the can bottom 2 can be secured stably.

And the bottom support member 14 is the outer side of the can 10 along the can axis | shaft O direction in the cyclic | annular convex part 6 among the edge part (lower end part of the can body 1) in the can body 2 in the can body 1, and the can bottom 2. Of the outer peripheral wall 9 which is disposed on the radially outer side of the inner peripheral wall 8 of the annular convex portion 6 and has a concave curved surface shape, along the can axis O direction. And three places are supported.
That is, in the longitudinal sectional view of the can 10 along the can axis O direction shown in FIGS. 5 and 7, the bottom support member 14 directs the can 10 in the radial direction, the can axis O direction, and a direction in which these are combined. Since three points are supported, the following effects can be obtained.

That is, the bottom support member 14 abuts on the end of the can body 1 on the can bottom 2 side (the lower end of the can body 1) and supports the end toward the inside in the radial direction. Sometimes, the can 10 is prevented from swinging (displacement) in the radial direction.
Further, the bottom support member 14 abuts on an outer edge (grounding portion 7) of the can 10 along the can axis O direction in the annular protrusion 6, and the end edge is inside the can 10 along the can axis O direction. Since it supports toward (above can 10), it can prevent that can 10 shakes in the direction of can axis O.
Further, the bottom support member 14 abuts on the outer peripheral wall 9 of the annular convex portion 6 and supports the outer peripheral wall 9 toward the inner side in the radial direction and toward the inner side of the can 10 along the can axis O direction. Therefore, the above-described operational effects can be obtained more remarkably.

Further, when the bottom support member 14 abuts on the outer peripheral wall 9 of the annular convex portion 6, when the bottom reforming process is performed with the inner peripheral wall 8 of the annular convex portion 6 facing outward in the radial direction, the can in the can body 1 The forming load in the radial direction acting on the end portion on the bottom 2 side is dispersed, and deformation of the end portion is suppressed.
Further, the bottom support member 14 abuts on the outer peripheral wall 9 of the annular convex portion 6, thereby acting on the outer edge (grounding portion 7) of the can 10 along the can axis O direction in the annular convex portion 6. The support load of the can 10 in the direction of the axis O is dispersed, and the deformation of the edge is suppressed.

Here, since the bottom support member 14 is in contact with the outer peripheral wall 9 is a part along the can axis O direction of the outer peripheral wall 9, the bottom support member 14 specifically contacts the outer peripheral wall 9. On the other hand, in a part along the direction of the can axis O, line contact is facilitated over the entire circumference in the circumferential direction.
Thereby, even if a variation (molding error) in the shape of the bottom 2 of the can bottom occurs in the previous step of the bottom reforming step, the bottom surface of the annular convex portion 6 has a concave curved outer peripheral wall 9 in the bottom reforming step. On the other hand, the bottom support member 14 can be reliably brought into contact with each other, and the above-described effects can be stably achieved.

Moreover, since the bottom support member 14 can be stably brought into contact with the outer peripheral wall 9 of the annular convex portion 6, the support load of the can 10 in the can axis O direction can be suppressed to a low load. Accordingly, the load on the can 10 itself and the equipment can be reduced.
Furthermore, the above-described excellent operational effects can be obtained by a simple configuration in which the bottom support member 14 is brought into contact with the outer peripheral wall 9 of the annular convex portion 6 at a part in the can axis O direction. It won't be complicated.

  As described above, according to the present embodiment, the can 10 to be bottom-reformed can be easily and stably supported without complicating the device structure and suppressing the support load of the can 10 in the direction of the can axis O. As a result, the desired shape of the can bottom 2 can be accurately applied to the expected position, sufficient strength can be secured, the production speed can be increased, and the productivity can be improved. be able to.

In the present embodiment, in the necking step, the opening end portion of the can body 1 is necked, and the outer side of the can 10 along the can axis O direction (above the can 10) rather than the portion other than the opening end portion. A neck portion 3 that gradually or gradually decreases in diameter as it goes toward and a planned flange portion 12 that is positioned outside the can 10 along the can axis O direction from the neck portion 3 are formed.
In the bottom reforming step, the bottom support member 14 is brought into contact with the can bottom 2 and the top support member 15 is brought into contact with the neck portion 3 so that the can 10 is placed inside the can 10 along the can axis O direction ( The inner peripheral wall 8 of the annular convex portion 6 is bottom-reformed in a state of being sandwiched toward the center of the can 10 and supported inward in the radial direction, thereby forming the concave portion 11.
Thereafter, in the flanging process, the flange portion 4 is flanged to form the flange portion 4.

  That is, the top support member 15 supports the neck portion 3 instead of the planned flange portion 12 in the open end portion of the can body 1, so there is no possibility of deforming the planned flange portion 12. That is, since the flange predetermined portion 12 without deformation is subsequently formed into the flange portion 4, the forming accuracy of the flange portion 4 is improved, and the sealing performance is ensured at the time of winding with the can lid (not shown). In addition, even if the pre-flange portion 12 is deformed at the time of the bottom reforming process, the shape of the flange part 4 is adjusted by performing the flanging process thereafter, and the sealing performance at the time of winding is also achieved. Can be secured.

  In addition, the neck portion 3 is stepped as it goes from the portion other than the opening end portion of the can body 1 (the outermost diameter portion of the can body 1) to the outside of the can 10 along the can axis O direction (above the can 10). Since the top support member 15 is brought into contact with the neck portion 3, the top support member 15 causes the can 10 to move along the can axis O direction. It can be supported toward the lower side of the can 10 and can also be supported toward the inside in the radial direction. Therefore, the can 10 can be supported easily and stably without complicating the structure of the apparatus.

  Further, the top support member 15 abuts against the neck portion 3 (the outer surface of the can body 1), not to the edge of the opening end portion of the can body 1 (the opening end surface of the flange planned portion 12). There is no possibility that the support member 15 is worn out early, and therefore the frequency of maintenance and component replacement can be kept low.

  Further, in the present embodiment, in the bottom reforming process, the molding roller 16 is brought into contact with the inner peripheral wall 8 of the can bottom 2 and the inner peripheral wall 8 is rolled over the entire circumference in the circumferential direction around the can axis O. Since the annular recess 11 extending over the entire circumference in the circumferential direction is formed on the inner peripheral wall 8, the strength of the can bottom 2 can be sufficiently increased.

Further, in the bottom support member 14, one support portion of the can body support portion 18, the nose support portion 19, and the outer peripheral wall support portion 20 is separated from the other two support portions, or these 3 Since the two support portions are separated from each other, by replacing one or more of these can body support portions 18, nose support portions 19 and outer peripheral wall support portions 20 with different shapes, It is possible to easily cope with various shapes of the can 10.
In the present embodiment, the can body support portion 18 included in the bottom support member 14, the nose support portion 19 and the outer peripheral wall support portion 20 are separated from each other. By replacing the nose support portion 19 and the outer peripheral wall support portion 20 with different shapes, it is possible to easily cope with various shapes of the can 10. Further, the nose support portion 19 and the outer peripheral wall support portion 20 may be formed separately from each other, and in this case, the above-described operational effects become more remarkable.

  Further, in the present embodiment, in the necking step, the neck portion 3 whose diameter is gradually reduced as it goes to the outside of the can 10 along the can axis O direction is formed, and the neck portion 3 is arranged in the can axis O direction. A plurality of step portions 13a to 13d are formed, and in the bottom reforming step, among the plurality of step portions 13a to 13d, the step portion located on the outermost side of the can 10 along the can axis O direction (most above the can 10). Since the top support member 15 is brought into contact with any one of the step portions 13a to 13c other than 13d, the can 10 can be supported more stably. That is, when the plurality of step portions 13a to 13d are formed in the neck portion 3, the step portion 13d located on the outermost side of the can 10 along the can axis O direction among the step portions 13a to 13d is the other step portion 13a. Since wrinkles are more likely to occur than ˜13c, by bringing the top support member 15 into contact with the other step portions 13a to 13c, the stability when supporting the can 10 is increased and the molding accuracy can be increased. More preferable.

In the bottom reforming step, among the plurality of step portions 13a to 13d, the step portions 13b to 13d other than the step portion 13a located on the innermost side of the can 10 along the can axis O direction (most below the can 10). Since the top support member 15 is brought into contact with either, the molding accuracy can be further increased.
That is, among the plurality of step portions 13a to 13d formed on the neck portion 3, the step portion 13a closest to the portion other than the opening end portion of the can body 1 (the outermost diameter portion of the can body 1) is other than that. Since the roundness (roundness of the can body 1 in a cross-sectional view perpendicular to the can axis O) is easily secured in the step portions 13b to 13d, the top of the step portions 13b to 13d having high roundness accuracy is ensured. By bringing the support member 15 into contact, the molding accuracy can be improved.

Further, in the present embodiment, in the flanging step, the plurality of step portions 13a to 13d of the neck portion 3 are moved from the portion other than the opening end portion of the can body 1 (the outermost diameter portion of the can body 1) in the direction of the can axis O. Since the taper surface is gradually reduced in diameter toward the outer side of the can 10 along the upper side (above the can 10), and the pre-flange portion 12 is formed on the flange portion 4, the following effects can be obtained.
That is, in the bottom reforming process, as described above, by using the step portions 13 a to 13 d of the neck portion 3, the molding accuracy of the can bottom 2 is sufficiently secured, and the desired strength is imparted to the can 10. In addition, after the bottom reforming process, the neck portion 3 can be reshaped into a tapered surface to enhance the beauty of the can 10.

  In the present embodiment, the top support member 15 has a cylindrical shape, and the neck support portion 21 that supports the neck portion 3 is formed on the inner peripheral surface of the peripheral wall. Therefore, the top support member 15 is excellent as described above. The top support member 15 having an operational effect can be formed with a simple structure.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

For example, in the above-described embodiment, in the bottom reforming step, the forming roller 16 is brought into contact with the inner peripheral wall 8 of the can bottom 2 and the inner peripheral wall 8 is rolled over the entire circumference in the circumferential direction. Although the annular recess 11 extending over the entire circumference in the circumferential direction is formed into the shape 8, the present invention is not limited to this.
That is, a plurality of groove-like recesses 11 extending along the circumferential direction may be formed on the inner peripheral wall 8 at intervals in the circumferential direction. In this case, a molding member other than the molding roller 16 may be used. In addition, when using the shaping | molding roller 16, what is necessary is just to project the some convex part 17 in the outer peripheral edge part of this shaping | molding roller 16 at intervals in the circumferential direction.

  Further, the composition of the Al alloy material of the plate material W is not limited to that described in the above embodiment.

  In addition, in the range which does not deviate from the meaning of this invention, you may combine each structure (component) demonstrated by the above-mentioned embodiment, a modification, and a remark etc., addition of a structure, omission, substitution, others It can be changed. Further, the present invention is not limited by the above-described embodiments, and is limited only by the scope of the claims.

  Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to this embodiment.

[Manufacturing confirmation when multiple steps are formed in the neck]
In the necking process, a total of four step portions 13a to 13d are formed on the neck portion 3 by the method for manufacturing the can 10 described in the above embodiment.
Further, the top support member 15 having the neck support portion 21 capable of supporting the second step portion 13b from the lower side of the can 10 (Example 1), and the final step portion positioned most above the can 10 What has the neck support part 21 which can support the step part 13d (Example 2) was prepared.
The can 10 was manufactured on the said conditions, 30 cans of the production base were extracted arbitrarily, the inspection metal mold | die was fitted, and the shakiness of the can 10 was confirmed by the touch of human hands.

[result]
In Example 1, rattling was not confirmed in all the cans 10.
In Example 2, rattling of most cans 10 was not confirmed, but a very small amount of cans 10 having a slightly large gap (play) with the inspection mold was confirmed. In addition, when this was confirmed visually, a slight wavy wrinkle in the circumferential direction was confirmed in the portion located in the step portion 13d of the neck portion 3, but it was not so much as to impair the beauty of the can 10. The product can be shipped as a product.

DESCRIPTION OF SYMBOLS 1 Can body 2 Can bottom 3 Neck part 4 Flange part 5 Dome part 6 Annular convex part 7 Grounding part (The outer edge of the can along the axial direction of the can in the annular convex part)
DESCRIPTION OF SYMBOLS 8 Inner peripheral wall 9 Outer peripheral wall 10 Can 11 Recessed part 12 Flange planned part 14 Bottom support member 15 Top support member 16 Forming roller (forming member)
17 convex portion 18 can body support portion 19 nose support portion 20 outer peripheral wall support portion 30 bottom reforming mechanism O can shaft W plate material

Claims (6)

While squeezing and squeezing the plate material into a bottomed cylindrical can having a can body and a bottom,
In the can bottom,
A dome part recessed toward the inside of the can along the can axis direction;
A squeezing and squeezing step that forms an annular convex portion that is continuous with the outer peripheral edge portion of the dome portion and protrudes toward the outside of the can along the can axis direction and extends along the circumferential direction around the can axis;
A bottom support member is brought into contact with the bottom of the can, and a top support member is brought into contact with an opening end of the can body, and the can is sandwiched toward the inside of the can along the can axis direction, And in a state where it is supported toward the inside in the radial direction perpendicular to the can axis,
A bottom reforming step of forming a concave portion that is recessed toward the outside in the radial direction on the inner peripheral wall by performing a bottom reforming process on the inner peripheral wall continuous with the dome portion among the annular convex portions,
In the bottom reforming step, by the bottom support member,
The end of the can bottom side of the can body;
Out of the can bottom, the outer edge of the can along the can axis direction in the annular projection,
Among the can bottoms, disposed on the radially outer side of the inner peripheral wall of the annular convex portion, and connected to the end of the can barrel on the can bottom side, on the can bottom side of the can barrel Supporting a part of the outer peripheral wall that forms a concave curved surface that gradually inclines toward the inside of the radial direction from the end portion toward the outside of the can along the can axis direction, along the can axis direction. A method for producing a can characterized by the above. It is a manufacturing method of the can according to claim 1,
Between the drawing and ironing step and the bottom reforming step,
Necking the opening end of the can body,
A neck portion that gradually or gradually decreases in diameter as it goes to the outside of the can along the can axis direction, rather than a portion other than the opening end portion,
Including a necking step for molding a planned flange portion located outside the can along the axial direction of the can from the neck portion,
In the bottom reforming step, the top support member is brought into contact with the neck portion,
As a subsequent process of the bottom reforming process,
A can manufacturing method comprising a flanging step of forming a flange portion by flanging the planned flange portion. It is a manufacturing method of the can according to claim 1 or 2,
In the bottom reforming step, a molding roller is brought into contact with the inner peripheral wall, and the inner peripheral wall is rolled over the entire circumference in the circumferential direction around the can axis, so that the inner circumferential wall has the entire circumference in the circumferential direction. A can manufacturing method, characterized in that the annular concave portion extending over is formed. Of a bottomed cylindrical can having a can body and a can bottom,
In the can bottom,
A dome part recessed toward the inside of the can along the can axis direction;
An annular convex portion that is continuous with the outer peripheral edge portion of the dome portion, protrudes toward the outside of the can along the can axis direction, and extends along the circumferential direction around the can axis, and is formed.
Among the annular protrusions, a bottom reforming mechanism for forming a recess recessed toward the outer side in the radial direction perpendicular to the can axis on the inner peripheral wall connected to the dome part,
A bottom support member that is close to and away from the bottom of the can, and capable of contacting the bottom of the can;
A top support member that approaches and separates from the opening end, and that can come into contact with the opening end,
A molding member that is close to and away from the inner peripheral wall and has a convex portion that can come into contact with the inner peripheral wall;
The bottom support member is
The end of the can bottom side of the can body;
Out of the can bottom, the outer edge of the can along the can axis direction in the annular projection,
Among the can bottoms, disposed on the radially outer side of the inner peripheral wall of the annular convex portion, and connected to the end of the can barrel on the can bottom side, on the can bottom side of the can barrel A part of the outer peripheral wall that forms a concave curved surface that gradually inclines inward in the radial direction as it goes from the end toward the outside of the can along the can axis direction so as to support the can axis direction. Composed of
With the bottom support member and the top support member sandwiching the can toward the inside of the can along the can axis direction, and supporting the can toward the inside of the radial direction,
A bottom reforming mechanism, wherein the convex portion is configured to press the inner peripheral wall toward the outer side in the radial direction to mold the concave portion. The bottom reforming mechanism according to claim 4,
The bottom support member is
A can body support portion that comes into contact with an end portion on the can bottom side of the can body;
Of the can bottom, a nose support portion that abuts on an outer edge of the can along the can axis direction in the annular convex portion,
Of the can bottom, comprising an outer peripheral wall support portion that abuts a part of the annular convex portion along the can axis direction of the outer peripheral wall,
Of the can body support part, the nose support part, and the outer peripheral wall support part, one is separated from the other two, or these three are separated from each other. Reform mechanism.   A bottom support member used in the bottom reforming mechanism according to claim 4 or 5.

Images