JP2018103227A - Bottom reform mechanism, top support member, and can manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bottom reform mechanism capable of suppressing a stroke of a top support member when applying bottom reform working to a can bottom and improving productivity, a top support member, and a can manufacturing method.SOLUTION: A bottom reform mechanism 1, in which a dome part and an annular projection 56 are formed on a can bottom 52 of a bottomed cylindrical can W2 and which molds a recess by pressurizing at least either of an inner peripheral wall 57 positioned radially inside a ground 59, projecting most downward, of an annular projection 56, and an outer peripheral wall 58 positioned radially outside, comprises: a top support member 3, capable of coming in contact with the opening end 51a of a can 51; a bottom support member 5 coming in contact with the can bottom 52; and a pressurizing part 6 that pressurizes at least either of the inner peripheral wall 57 and the outer peripheral wall 58 to mold a recess, the top support member 3 comprising an end edge presser 9 which comes in contact with the upper end edge of the opening end 51a.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a bottom reforming mechanism that performs a bottom reforming process on the bottom of a can such as a DI can or a bottle can, a top support member used therefor, and a method for manufacturing the can.

Conventionally, a bottle can is formed by punching a rolled material (plate material) made of an aluminum alloy material into a disk-shaped blank, cupping the blank to obtain a cup-shaped body, and DI processing (drawing) on the cup-shaped body. It is made into a bottomed cylindrical DI can by performing ironing processing, and can be made into a bottle by performing necking processing, screw forming processing, curling processing, throttle processing, etc. on the DI can. “DI” is an abbreviation for “Drawing & Ironing”.
The bottle can is filled with contents such as a beverage, and a cap is attached to the opening end of the bottle can to seal it.

By the way, 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.

In reducing the weight of a bottle can, it is effective to reduce the thickness (thickness) of the can, but if the thickness is simply reduced, problems such as bottom growth and buckling occur. The bottom growth is a phenomenon in which the annular convex portion (rim) of the can bottom is deformed by an increase in the internal pressure of the can in which the contents are enclosed. When bottom growth occurs, the height of the can (the total length in the can axis direction) changes, causing problems in manufacturing and shipping. Buckling is a phenomenon in which the dome portion of the bottom of the can is inverted when the internal pressure of the can exceeds the pressure strength.
For the purpose of preventing such deformation of the bottom of the can, for example, bottom reform processing (bottom profile reformer processing, BPR processing) by a bottom reform mechanism as shown in Patent Document 1 below has been proposed.

JP 2016-47541 A

  However, in the conventional bottom reforming mechanism, since the neck portion of the can body is pressed by the top support member, the stroke for moving the top support member toward and away from the can body is large. In particular, in the case of a bottle can, a base part in which a thread forming part is formed is disposed above the neck part, and the stroke of the top support member with respect to the neck part becomes larger.

  The present invention was made in view of such circumstances, and when performing bottom reform processing on the bottom of the can, a bottom reforming mechanism that can reduce the stroke of the top support member and improve productivity, It aims at providing the top support member used for this, and the manufacturing method of a can.

One aspect of the present invention is a direction toward the opening end side of the can body from the can bottom along the can axis direction to the can bottom of a bottomed cylindrical can having a can body and a can bottom. A dome portion that is recessed upward, and an outer peripheral edge portion of the dome portion, protrudes downward from the opening end portion along the can axis direction toward the can bottom side, and around the can axis An annular convex portion extending along the circumferential direction of the inner circumferential wall and the diameter of the grounding portion that protrudes downward most among the annular convex portions and located radially inside the can axis. A bottom reforming mechanism for forming a recess by pressing at least one of the outer peripheral walls located outside in the direction, and a top support member capable of abutting on the opening end and abutting on the bottom of the can Bottom support member, at least one of the inner peripheral wall and the outer peripheral wall And a pressing portion for shaping the recess to press the said top support member, characterized in that it comprises the abutting edge pressing portion at the upper end edge of the open end.
Moreover, the top support member which concerns on 1 aspect of this invention is used for the bottom reform mechanism mentioned above, It is characterized by the above-mentioned.
One embodiment of the present invention includes a cupping step of drawing a disk-shaped blank to form a cup-like body, and drawing and ironing the cup-like body to include a can body and a can bottom. A dome portion recessed toward the upper end, which is a direction from the can bottom along the can axis direction toward the opening end side of the can body, and the dome portion. And an annular convex portion extending in a circumferential direction around the can axis, and projecting downward from the opening end portion along the can axis direction toward the can bottom side. Of the annular squeezing step, a grounding portion that protrudes downwardly among the annular convex portions, an inner peripheral wall located radially inside perpendicular to the can axis, and an outer peripheral wall located radially outside By pressing at least one of the bottom reformers that form the recess And a bottom reforming step in which a top support member is brought into contact with the opening end, a bottom support member is brought into contact with the bottom of the can, and the inner peripheral wall and The recess is formed by pressing at least one of the outer peripheral walls with a pressing portion, and the top support member is brought into contact with an upper edge of the opening end.

  According to the bottom reforming mechanism, the top support member, and the can manufacturing method of the present invention, the top support member (the edge pressing portion) abuts on the upper edge of the opening end of the can body. For this reason, when performing bottom reform processing to the annular convex part of a can bottom, the stroke which makes a top support member approach and separate from the opening end part of a can body can be shortened. Since the stroke of the top support member can be kept small, productivity can be increased.

In the bottom reforming mechanism, it is preferable that the top support member includes an inner fitting portion that fits inside the opening end portion.
Moreover, in the said manufacturing method of a can, it is preferable to make the said top support member fit inside the said opening edge part at the said bottom reform process.

  In this case, since the top support member (the inner fitting portion thereof) is fitted into the opening end portion of the can body, the center axis of the top support member and the can axis of the can, which is a workpiece, can be easily aligned (centering property is improved). Increase), it is possible to improve the molding accuracy of the bottom reforming process.

  Further, the top support member (the edge pressing portion thereof) abuts the upper edge of the opening end portion of the can body from the can axis direction, and the top support member (the inner fitting portion thereof) is fitted into the opening end portion. Therefore, the strength of the opening end during molding is sufficiently ensured, and air leakage from the inside of the can to the outside through the opening end is suppressed. That is, the reduction of the internal pressure of the can during the molding can be suppressed and the internal pressure can be kept high, the unintended deformation of the can is prevented, and the moldability is stably improved. Therefore, productivity can be improved.

  In the bottom reforming mechanism, the inner fitting portion is a tapered guide portion whose outer diameter gradually decreases from the top support member toward the bottom support member along the central axis direction of the top support member. And a fitting portion that is disposed between the guide portion along the central axis direction and the end edge pressing portion and has a constant outer diameter along the central axis direction.

  In this case, since the inner fitting portion has a tapered guide portion, first, the guide portion is surely inserted into the opening end portion of the can body, and the can shaft of the can and the central axis of the top support member are guided by the guide portion. Can be smoothly fitted into the opening end from the state where the two are coaxially aligned. For this reason, the support state of the opening end portion of the can body by the top support member is stabilized, and the moldability is improved.

  In the bottom reforming mechanism, it is preferable that an angle formed between the guide portion and the central axis is 10 to 20 degrees in a longitudinal sectional view of the top support member including the central axis.

In this case, since the acute angle of the acute angle and the obtuse angle formed between the central axis of the top support member and the guide portion in the longitudinal sectional view of the top support member is 10 to 20 °, The guide portion can be reliably and smoothly inserted into the opening end portion.
Specifically, since the angle is 10 ° or more, when the top support member is moved toward the opening end portion of the can body, the guide portion collides with the opening end portion and the opening It is possible to reliably prevent such a problem that the end portion is crushed and to stably insert the guide portion into the open end portion.
Further, since the angle is 20 ° or less, the outer periphery of the guide portion is easily slidably contacted with the inner periphery of the opening end portion, and the center axis of the top support member and the can shaft are smoothly centered (coaxially aligned). can do. That is, since the guide portion can be gently slidably contacted with the opening end portion and gradually centered, the load on the opening end portion can be suppressed to be small, and deformation and the like can be suppressed.

In the bottom reforming mechanism, the top support member preferably includes a surrounding portion formed so as to surround the outside of the opening end portion.
In the can manufacturing method, in the bottom reforming step, it is preferable that the top support member surrounds the outside of the opening end.

  In this case, since the top support member (the surrounding portion) surrounds the outside of the opening end portion of the can body, from the portion of the top support member that contacts the upper edge of the opening end portion of the can body (edge holding portion) A peripheral wall that hangs down toward the bottom support member side is formed. With this configuration, air leakage from the inside of the can to the outside through the opening end of the can body is suppressed. Therefore, a decrease in the internal pressure of the can during molding can be suppressed and the internal pressure can be kept high, unintentional deformation of the can is prevented, moldability is stably increased, and productivity is improved.

  In the bottom reforming mechanism, the can is preferably a DI can in which the can body has a cylindrical shape.

  In this case, the can subjected to the bottom reforming process by the bottom reforming mechanism is, for example, a DI can of an intermediate formed body (work) manufactured into a bottle can. Generally, it can be considered that the total length of the can in the can axis direction (total height of the can) can be changed by performing the bottom reforming process on the can. In the above configuration, the DI can is subjected to the bottom reforming process. Therefore, the overall length in the can axis direction of the bottle can formed by performing various processes on the DI can in a bottle can manufacturing apparatus in a subsequent process is stable.

  Further, in the bottom reforming mechanism, the can includes a neck portion that gradually decreases in diameter toward the opening end portion of the can body, and a base portion that is continuously provided above the neck portion. It is preferable that the bottle can be provided.

  In this case, the can subjected to the bottom reforming process by the bottom reforming mechanism is a bottle can. For example, when performing bottom reform processing on a bottle can, if you try to hold the neck part of the bottle can with the top support member, the stroke of the top support member will be as much as the base part is placed above the neck part. Must be set large. On the other hand, according to the present invention, the top support member (the edge pressing portion thereof) presses the upper edge of the opening end portion of the bottle can, so that the above-described stroke of the top support member can be suppressed to be small. Especially, it becomes particularly remarkable. In the case of a bottle can, since the curl portion is formed at the upper edge of the opening end of the can body to enhance the strength, the top support member is directly applied to the upper edge. Even if they are brought into contact with each other, there is little risk of deformation or the like at the opening end.

  According to the bottom reforming mechanism, the top support member, and the can manufacturing method of the present invention, when the bottom reforming process is performed on the bottom of the can, the stroke of the top support member can be suppressed, and the productivity can be improved.

It is a flowchart which shows the manufacturing method of the bottle can which concerns on 1st Embodiment of this invention. It is a schematic diagram explaining the change of the shape of the can for every manufacturing process of a bottle can. It is a longitudinal cross-sectional view which shows the principal part of the can bottom of a bottle can. It is a longitudinal cross-sectional view which shows the bottom reform mechanism and can (DI can) of 1st Embodiment, (a) The state before the top support member of a bottom reform mechanism supports the opening edge part of a can, (b) Top support The member has shown the state which supported the opening edge part of the can. It is the modification of the bottom reform mechanism of 1st Embodiment, (a) The state before a top support member supports the opening end part of a can, (b) The state which the top support member supported the opening end part of the can Represents. It is a flowchart which shows the manufacturing method of the bottle can which concerns on 2nd Embodiment of this invention. It is a longitudinal cross-sectional view which shows the bottom reform mechanism and can (bottle can) of 2nd Embodiment, (a) The state before the top support member of a bottom reform mechanism supports the opening edge part of a can, (b) Top support The member has shown the state which supported the opening edge part of the can. It is the modification of the bottom reform mechanism of 2nd Embodiment, (a) The state before a top support member supports the opening end part of a can, (b) The state which the top support member supported the opening end part of the can Represents.

<First Embodiment>
Hereinafter, a bottom reforming mechanism, a top support member, and a can manufacturing method according to a first embodiment of the present invention will be described with reference to FIGS. Note that the drawings used for describing the embodiments of the present invention may show enlarged or excerpted portions that are essential to make the features of the present invention easier to understand. The dimensional ratio is not always the same as the actual one.

The “can” in the embodiment of the present invention is, for example, a DI can and a bottle can made as an intermediate molded body (work). First, the manufacturing method of DI can and a bottle can is demonstrated.
As shown in FIG. 1 and FIG. 2, the bottle can B has a plate blanking process S01, a cupping process (drawing process) S02, a DI process (drawing and ironing process) S03, a trimming process S04, and a printing / painting (can outer surface) process. The can is manufactured through a coating (can inner surface) step S06, a bottom reforming step S07, a necking step S08, a trimming step S09, a screw forming step S10, a curling step S11, and a throttle step S12.

In the plate material punching step S01, for example, a rolled material (plate material) made of an aluminum alloy material or the like is punched to form a disc-shaped blank W0 as shown in FIG.
In the cupping step (drawing step) S02, the blank W0 is drawn (capping) by a cupping press and formed into a cup-like body W1 as shown in FIG.

  In the DI step (drawing and ironing step) S03, the cup body W1 is subjected to drawing and ironing (redrawing and ironing) by the DI can manufacturing apparatus, and as shown in FIG. A bottomed cylindrical can (DI can which is an intermediate formed body of the bottle can B) W2 provided with a body portion 51 and a can bottom (can bottom portion) 52 is formed. Specifically, the DI can W2 includes a can body 51 that is a cylindrical peripheral wall and a can bottom 52 that is a generally disc-shaped bottom wall. The central axis of the can body 51 of the DI can W2 and the central axis of the can bottom 52 are arranged coaxially with each other. In the present embodiment, these common axes are referred to as can axes.

In the DI process, the can bottom 52 includes a dome portion 55 that is recessed upward from the can bottom 52 along the can axis direction toward the opening end portion 51a of the can body 51, and an outer portion of the dome portion 55. An annular convex portion (rim) 56 that continues to the peripheral edge and projects downward from the opening end 51a along the can axis direction toward the can bottom 52, and extends along the circumferential direction around the can axis. Are molded (see FIG. 3). In addition, the straight line shown with a dashed-dotted line in FIG. 3 represents the can axis | shaft.
The annular convex portion 56 includes a grounding portion (nose portion) 59 that protrudes downward most in the can bottom 52, and an inner peripheral wall (counter portion) 57 that is located on the radially inner side perpendicular to the can axis of the grounding portion 59. And an outer peripheral wall (heel portion) 58 positioned on the outer side in the radial direction of the ground contact portion 59.

  1 and 2, the DI can W2 that has undergone the DI step S03 has ears formed at the opening end portion 51a of the can body 51 and has a non-uniform height. Therefore, a trimming device is used in the trimming step S04. Then, the opening end 51a is trimmed to form a DI can W2 in which the height of the opening end 51a of the can body 51 is evenly aligned over the entire circumference, as shown in FIG.

Next, after the DI can W2 is washed to remove oil and the like, it is subjected to surface treatment and dried, and the outer surface of the DI can W2 is printed and coated (printing / coating (can outer surface) step S05). Is applied to the inner surface (painting (can inner surface) step S06), thereby obtaining a DI can W2 as shown in FIG.
A polyester-based paint is used for coating the outer surface of the DI can W2. In the exterior coating, printing and exterior finish coating are performed. Printing and exterior finish painting are baked and dried at the same time. As will be described later, a neck portion 54 and a base portion 53 having a screw forming portion are formed at the opening end portion 51a of the bottle can B. The neck portion 54 and the base portion 53 are formed by coating. It is performed in a step subsequent to steps S05 and S06. When the neck portion 54 and the base portion 53 are molded, a strong load acts on the coating film, and if the coating film is not sufficiently baked, an influence on the unplugging property occurs. For this reason, the temperature of baking / drying to the DI can W2 is set higher than that of, for example, a two-piece can.
In addition, after the outer surface coating, the inner surface coating and the inner surface coating are dried and baked. The coating on the inner surface of the DI can W2 is performed by spraying the paint from the opening end 51a toward the can bottom 52 with a spray nozzle. By drying the sprayed paint, a coating film is formed on the inner surface of the can to impart corrosion resistance.

The DI can W2 is transferred to a bottom reforming apparatus, and a bottom reforming process is performed on the can bottom 52 (bottom reforming step S07). In the bottom reforming step S07, the bottom reforming mechanism 1 presses at least one of the inner peripheral wall 57 and the outer peripheral wall 58 among the annular convex portions 56 of the can bottom 52, thereby forming the concave portion 60 as shown in FIG. Mold. In the example of the present embodiment, by performing a bottom reforming process on the inner peripheral wall 57 of the annular convex portion 56, an annular concave portion 60 that is recessed radially outward and extends along the circumferential direction is formed in the inner peripheral wall 57. Is formed.
The configuration of the bottom reforming mechanism 1 and specific actions (operations, etc.) in the bottom reforming step S07 of the bottom reforming mechanism 1 will be described later.

  Next, the DI can W2 is transferred to a bottle can manufacturing apparatus. Steps S08 to S12 described below are manufacturing steps in the bottle can manufacturing apparatus.

In the bottle can manufacturing apparatus, a die portion 53 and a neck portion are formed by performing die processing (necking processing) stepwise on the open end portion 51a of the can body 51 using a plurality of types of die processing tools (necking molds). The part 54 is molded (necking step S08). The neck portion 54 is formed in a tapered shape that gradually decreases in diameter from the outermost diameter portion (body portion) of the can body 51 toward the opening end portion 51a side (that is, upward) from the can bottom 52 along the can axis direction. Is done. The base portion 53 is disposed adjacent to the upper portion of the neck portion 54 and is formed into a cylindrical shape having the smallest diameter in the can body 51. The base portion 53 is provided continuously above the neck portion 54.
Further, if necessary, trimming of the opening end portion 51a having uneven heights is performed between a plurality of types of die processing using a trimming tool of a rotary processing tool (trimming step S09).
As a result, as shown in FIG. 2 (f), a bottle can W <b> 3 having a base portion 53 and a neck portion 54 at the opening end portion 51 a of the can body 51 is formed.

  Next, the base 53 of the can body 51 is subjected to screw forming using a screw forming tool of a rotary processing tool (screw forming step S10). Thereby, a screw forming part is formed in the base part 53.

Next, the base 53 of the can body 51 is subjected to curling using a curling tool of a rotating tool (curling step S11), and throttle processing using a throttle processing tool (curl caulking tool) of the rotating tool ( A throttle step S12) is performed.
Thereby, the bottle can B as shown in FIG.2 (g) is manufactured. The bottle can B is filled with contents such as a beverage in a later process than the throttle process S12, and a cap is attached to the cap 53 so as to be sealed.

  Next, the bottom reforming apparatus and the bottom reforming mechanism 1 used therefor will be described. In the present embodiment, a bottom reforming device is provided in a process preceding the bottle can manufacturing device. Of the bottom reforming apparatus, for structures other than the bottom reforming mechanism 1 described in the present embodiment, for example, the same structure as the can bottom re-forming apparatus described in US Pat. No. 5,704,241 of the well-known document is used. Can do. Therefore, in this embodiment, the description of a well-known structure in the bottom reforming device is omitted.

  The bottom reforming mechanism 1 presses at least one of the inner peripheral wall 57 and the outer peripheral wall 58 among the annular convex portions 56 of the can bottom 52 of the work can (DI can) W2 supplied to the bottom reforming device, At least one of a recess 60 (see FIG. 3) that is recessed radially outward in the inner peripheral wall 57 and a recess (not shown) that is recessed radially inward in the outer peripheral wall 58 is formed.

As shown in FIGS. 4A and 4B, the bottom reforming mechanism 1 has a bottom support member 5 that is close to and away from the can bottom 52 in the can axis direction, and that can abut against the can bottom 52. While approaching and separating in the can axis direction with respect to the opening end portion 51a of the can body 51, approaching in the radial direction with respect to the top support member 3 capable of contacting the opening end portion 51a and the annular convex portion 56 of the can bottom 52 And a pressing portion 6 that forms a recess by pressing at least one of the inner peripheral wall 57 and the outer peripheral wall 58. In the example of this embodiment, the recessed part 60 is shape | molded when the press part 6 presses the inner peripheral wall 57 toward a radial direction outer side.
The central axes C of the bottom support member 5 and the top support member 3 are arranged coaxially with the can axis of the DI can W2 to be bottom-reformed. Further, the center axis C and the can axis are arranged coaxially with a spindle axis described later.

  The bottom support member 5 includes an end portion on the can bottom 52 side of the can body 51 (that is, a lower end portion of the can body 51), and a ground contact portion 59 (a lower end edge of the can bottom 52) of the annular protrusion 56 of the can bottom 52. The outer bottom wall 58 of the annular projection 56 of the can bottom 52 is configured to be supported.

  The top support member 3 has an inner fitting portion 8 that fits inside the open end 51a of the DI can W2, and an upper end edge (the upper end open edge of the DI can W2) of the open end 51a in the can axis direction. And an edge pressing portion 9 that comes into contact with each other.

  The inner fitting portion 8 has a substantially columnar shape, and has an outer diameter that is equal to or smaller than the inner diameter of the opening end portion 51a of the DI can W2. The inner fitting portion 8 includes a guide portion 10 and a fitting portion 11. The guide portion 10 is disposed at the end of the inner fitting portion 8 on the bottom support member 5 side along the central axis C direction of the top support member 3, and from the top support member 3 to the bottom support member 5 along the central axis C direction. It has a tapered shape in which the outer diameter gradually decreases toward the side. The fitting part 11 is arrange | positioned between the guide part 10 in alignment with the central axis C direction, and the edge holding | suppressing part 9, and the outer diameter is made constant along the central axis C direction.

  In a longitudinal sectional view of the top support member 3 including the central axis C (see FIG. 4A), the guide portion 10 (an extension thereof) and the central axis C of the top support member 3 are formed to intersect each other. Of the acute angle and the obtuse angle, the acute angle is 10 to 20 °, and is about 15 ° in the example of the present embodiment.

The edge pressing part 9 has a disk shape and has an outer diameter larger than the outer diameters of the inner fitting part 8 and the opening end part 51a of the DI can W2. The end surface of the edge pressing portion 9 facing the bottom support member 5 along the central axis C direction has a ring-shaped planar shape.
When the top support member 3 is moved closer to the DI can W2 in the can axis direction and the inner fitting portion 8 is inserted into the opening end portion 51a of the can body 51, first, the guide portion 10 is opened. The fitting portion 11 is inserted (fitted) into the opening end portion 51 a so as to be inserted into the portion 51 a and guided by the guide portion 10. Then, as shown in FIG. 4B, the end surface of the edge pressing portion 9 comes into contact with the upper edge of the opening end portion 51a of the DI can W2 from above.

  In the example of this embodiment, the pressing part 6 is a forming roller. The pressing portion 6 is a molding die having a disk shape, a cylindrical shape, or a columnar shape, and the central axis C <b> 1 extends in parallel with the central axes C of the top support member 3 and the bottom support member 5. The pressing portion 6 is provided on the bottom spindle 4 so as to be rotatable around the central axis C1 and slidable in a radial direction perpendicular to the central axis C1.

A schematic configuration of the bottom reforming apparatus will be described.
Although not particularly shown, the bottom reforming apparatus is composed of an apparatus frame that is a base of the apparatus, a rotary shaft that is supported by the apparatus frame and driven to rotate, and a work can In the embodiment, a star wheel (turret) in which a plurality of pockets holding DI cans W2) are formed, and a plurality of bottom reform mechanisms 1 supported by the rotating shaft and provided corresponding to the pockets of the star wheel, It has.

  A can body 51 of the can is held in each pocket of the star wheel by air adsorption or the like. By rotating the rotating shaft around the central axis with respect to the apparatus frame, the star wheel and the bottom reforming mechanism 1 provided integrally with the rotating shaft are rotated around the central axis of the rotating shaft.

The bottom reforming mechanism 1 includes a top spindle 2 having the top support member 3 that supports the opening end 51a of the can, and a bottom spindle 4 having the bottom support member 5 that supports the can bottom 52 of the can. Yes. The top spindle 2 and the bottom spindle 4 are opposed to each other with a star wheel pocket in between, spaced apart from each other in the spindle axis direction (corresponding to the direction of the central axis C. The same applies hereinafter).
The spindle axis of the top spindle 2 and the center axis C of the top support member 3, and the spindle axis of the bottom spindle 4 and the center axis C of the bottom support member 5 are relative to the can axis of the can held in each pocket of the star wheel. Arranged coaxially.

The bottom spindle 4 includes a bottom cam follower. The bottom cam follower is provided integrally with the apparatus frame, is disposed on the radially outer side of the rotation shaft, and engages with a cylindrical cam extending around the central axis of the rotation shaft.
The cylindrical cam forms a predetermined trajectory whose position along the direction of the central axis changes as it goes around the central axis of the rotating shaft. By guiding the bottom cam follower along this track, the bottom cam follower reciprocates within a predetermined stroke L1 along the spindle axis direction. The bottom support member 5 connected to the bottom cam follower also reciprocates within a predetermined stroke L1 along the spindle axis direction.

The bottom spindle 4 includes the pressing portion 6 that can contact the can bottom 52 of the can held by the bottom support member 5. The pressing portion 6 is connected to the pressing cam follower of the bottom spindle 4. The pressing cam follower is provided integrally with the apparatus frame, is arranged on the outer side in the radial direction of the rotating shaft, and engages with a cylindrical cam extending around the central axis of the rotating shaft.
The cylindrical cam forms a predetermined trajectory whose position along the direction of the central axis changes as it goes around the central axis of the rotating shaft. When the pressing cam follower is guided along this track, the pressing cam follower reciprocates in the range of a predetermined stroke L2 larger than the stroke L1 along the spindle axis direction. The pressing portion 6 reciprocates in the range of a predetermined stroke L1 along the spindle axis direction, and a difference (L2−) between the stroke L2 and the stroke L1 by the action of the link portion 7 provided on the bottom spindle 4. In accordance with L1), the linear motion in the spindle axis direction is a range of strokes converted into a slide movement in the spindle radial direction orthogonal to the spindle axis (corresponding to the radial direction orthogonal to the central axis C. The same applies hereinafter) It also reciprocates in the spindle radial direction.
Thereby, the pressing part 6 can press the inner peripheral wall 57 of the annular convex part 56 of the can bottom 52 held by the bottom support member 5.

  Further, the device frame is provided with a drive gear that is coaxial with the rotation shaft and is rotatable around the central axis of the rotation shaft. The bottom spindle 4 is provided with a driven gear that meshes with the drive gear. The driving gear rotates the driven gear about the spindle axis (corresponding to the circumferential direction about the central axis C. The same applies hereinafter), so that the pressing portion 6 connected to the driven gear is rotated against the bottom support member 5 by the spindle. Rotate around the axis.

The top spindle 2 includes a top cam follower. The top cam follower is provided integrally with the apparatus frame, is arranged on the outer side in the radial direction of the rotating shaft, and engages with a cylindrical cam extending around the central axis of the rotating shaft.
The cylindrical cam forms a predetermined trajectory whose position along the direction of the central axis changes as it goes around the central axis of the rotating shaft. By guiding the top cam follower along this track, the top spindle 2 reciprocates within a predetermined stroke L3 along the spindle axis direction. However, the top support member 3 of the top spindle 2 is brought into contact with the opening end 51a of the can in the middle of the stroke L3, and after the contact, the forward movement toward the further can is performed by the action of the elastic member. Stopped. For this reason, the stroke L4 of the top support member 3 is set smaller than the stroke L3.

Next, an example of the operation of the bottom reformer will be described. The following operations of the bottom reforming device are all operations in the above-described bottom reforming step S07.
The rotating shaft is rotated around its central axis by the rotational driving force input from the drive motor. Accordingly, the bottom spindle 4 and its bottom support member 5 are directed toward the can held in the star wheel pocket by the action of the cylindrical cam of the apparatus frame, the bottom cam follower and the pressing cam follower engaged therewith. Moves forward in the spindle axis direction. That is, the bottom spindle 4 moves by the stroke L1 toward the top spindle 2 side along the spindle axis direction. Thus, the bottom support member 5 is brought into contact with the can bottom 52 of the can.

  Specifically, the bottom wall of the bottom support member 5 comes into contact with the ground contact portion 59 and the outer peripheral wall 58 of the can bottom 52 of the can from the spindle axis direction, and the end of the can body 51 on the can bottom 52 side (can The vicinity of the lower end portion of the body 51 is fitted into the peripheral wall of the bottom support member 5. Moreover, the press part 6 will be in the state arrange | positioned close to the can bottom 52 of a can. Specifically, the outer peripheral edge portion (saddle portion) of the pressing portion 6 is disposed to face the inner peripheral wall 57 of the annular convex portion 56 of the can bottom 52 from the inner side in the spindle radial direction.

  Further, the top spindle 2 and its top support member 3 are moved forward in the spindle axial direction toward the can held in the pocket of the star wheel by the action of the cylindrical cam of the device frame and the top cam follower engaged therewith. . That is, the top spindle 2 moves along the spindle axis direction by the stroke L3 toward the bottom spindle 4 side. Thereby, the top support member 3 is made to contact | abut with respect to the opening edge part 51a of a can.

  Specifically, in the middle of the stroke L3, the inner fitting portion 8 of the top support member 3 is fitted into the opening end portion 51a of the can body 51, and the edge pressing portion 9 is the opening end portion. It is made to contact | abut to the upper edge of 51a from a spindle axial direction. Thus, after the edge holding part 9 of the top support member 3 abuts on the opening end 51a of the can, the elastic member is elastically deformed according to the amount of forward movement of the top spindle 2 thereafter, so that the top The forward movement of the support member 3 toward the bottom spindle 4 side (can side held by the star wheel) along the spindle axial direction is stopped. As a result, the top support member 3 moves toward the bottom spindle 4 side along the spindle axis direction by a stroke L4 smaller than the stroke L3.

  As a result, as shown in FIG. 4B, the can is sandwiched between the bottom support member 5 and the top support member 3 from both sides in the spindle axial direction. At this time, the can is supported by the support members 3 and 5 while being pressurized in the can axis direction (spindle axis direction) by the restoring deformation force of the elastic member.

  Next, the pressing cam follower moves forward toward the top spindle 2 along the spindle axis direction according to the difference (L2−L1) between the stroke L2 and the stroke L1. At this time, the link portion 7 connected to the pressing cam follower converts the linear movement of the pressing cam follower in the spindle axial direction into a sliding movement in the spindle radial direction. As a result, the pressing portion 6 connected to the link portion 7 is moved outward in the spindle radial direction, and the outer peripheral edge portion (the flange portion) of the pressing portion 6 is the inner side of the annular convex portion 56 of the can bottom 52. By pressing the peripheral wall 57, a concave portion 60 that is recessed outward in the radial direction is formed on the inner peripheral wall 57 (see FIG. 3).

  Further, when the driving gear rotates the driven gear around the spindle axis, the link portion 7 and the pressing portion 6 connected to the driven gear rotate around the spindle axis. As a result, the pressing portion 6 rolls on the inner peripheral wall 57 of the annular convex portion 56 (that is, rotates around the central axis C1 of the pressing portion 6 while revolving around the spindle axis) A ring-shaped recess 60 extending along the circumferential direction is formed.

  Thereafter, the pressing portion 6 is first retracted from the inner peripheral wall 57 toward the inner side in the spindle radial direction in the reverse procedure. Further, the top spindle 2 and the bottom spindle 4 move backward in the spindle axial direction with respect to the can, and the support state of the can by the top support member 3 and the bottom support member 5 is released.

  Thus, the can (DI can W2) whose bottom reforming process has been performed on the can bottom 52 by the bottom reforming apparatus is transferred to a bottle can manufacturing apparatus installed in a subsequent process of the bottom reforming apparatus, and various types of molding are performed. The bottle can B is made by processing.

  According to the bottom reforming mechanism 1, the top support member 3, and the can manufacturing method of the present embodiment described above, the top support member 3 (the edge pressing portion 9) is located above the open end 51 a of the can body 51. Abuts the edge. For this reason, when performing bottom reform processing to the annular convex part 56 of the can bottom 52, the said stroke L4 which approaches the top support member 3 with respect to the opening end part 51a of the can body 51 can be shortened. Since the stroke L4 of the top support member 3 is kept small, productivity can be improved.

  Moreover, in this embodiment, since the top support member 3 (the inner fitting part 8) fits in the opening end part 51a of the can body 51, the center axis C of the top support member 3 and the can of the can as a workpiece It becomes easier to match the axis (higher centering performance), and the molding accuracy of bottom reforming can be improved.

  Further, the top support member 3 (the edge holding portion 9) abuts the upper edge of the opening end portion 51a of the can body 51 from the can axis direction, and the top support member 3 (the inner fitting portion 8) opens. Since it fits in the end 51a, the strength of the open end 51a during molding is sufficiently ensured, and air leakage from the inside of the can to the outside through the open end 51a is suppressed. . That is, the reduction of the internal pressure of the can during the molding can be suppressed and the internal pressure can be kept high, the unintended deformation of the can is prevented, and the moldability is stably improved. Therefore, productivity can be improved.

  Moreover, in this embodiment, since the internal fitting part 8 of the top support member 3 has the taper-shaped guide part 10, first, the guide part 10 is reliably inserted in the opening end part 51a of the can body 51, From the state in which the can shaft of the can and the center axis C of the top support member 3 are coaxially aligned by the guide portion 10, the fitting portion 11 can be smoothly fitted into the open end portion 51a. For this reason, the support state of the open end 51a of the can body 51 by the top support member 3 is stabilized, and the moldability is improved.

Moreover, in this embodiment, since the angle formed between the guide part 10 and the central axis C is 10-20 degrees in the longitudinal cross-sectional view of the top support member 3 containing the central axis C, the following effect is obtained. Play.
That is, in the longitudinal sectional view of the top support member 3, the acute angle and the obtuse angle formed between the central axis C of the top support member 3 and the guide portion 10 are 10 to 20 °, The guide portion 10 can be reliably and smoothly inserted into the open end portion 51 a of the can body 51.
Specifically, since the angle is 10 ° or more, when the top support member 3 is moved closer to the opening end 51a of the can body 51, the guide portion 10 is moved relative to the opening end 51a. It is possible to reliably prevent a problem that the opening end portion 51a is crushed and collide, and the guide portion 10 can be stably inserted into the opening end portion 51a.
Further, since the angle is 20 ° or less, the outer periphery of the guide portion 10 is easily brought into sliding contact with the inner periphery of the opening end portion 51a, and the center axis C of the top support member 3 and the can shaft can be smoothly centered (coaxially). Centering). That is, since the guide portion 10 can be gently slidably contacted with the opening end 51a and gradually centered, the load on the opening end 51a can be suppressed to be small, and deformation and the like can be suppressed.

  Further, in the present embodiment, the can subjected to the bottom reforming process by the bottom reforming mechanism 1 is the DI can W2 that is an intermediate formed body (work) that is manufactured into the bottle can B. Generally, it is conceivable that the total length of the can in the can axis direction (total height of the can) can be changed by performing the bottom reforming process on the can. In this embodiment, however, the DI can W2 is subjected to the bottom reforming process. Therefore, the bottle can B formed by subjecting the DI can W2 to various processes in a bottle can manufacturing apparatus in a subsequent process has a stable overall length in the can axis direction.

5A and 5B show a modification of the top support member 3 described in this embodiment. In this modified example, the top support member 3 includes an inner fitting portion 8, an end edge pressing portion 9, and an end edge pressing portion 9 (outer peripheral edge thereof) along the central axis C direction of the top support member 3. 5 projecting toward the side 5 and formed so as to cover the inner fitting portion 8 from the outside in the radial direction, and the plate thickness (thickness) of the opening end portion 51a of the can body 51 between the inner fitting portion 8 and the inner fitting portion 8 And a cylindrical surrounding portion 12 arranged with a gap therebetween. That is, the surrounding part 12 is formed so as to surround the outside of the opening end part 51a. The surrounding portion 12 has an inner diameter that is equal to or larger than the outer diameter of the opening end portion 51 a of the can body 51. In the illustrated example, the surrounding portion 12 is fitted to the outside of the opening end portion 51a.
In the bottom reforming step S07, the top support member 3 (the surrounding portion 12) surrounds the outside of the opening end portion 51a.

  According to this modification, since the top support member 3 (the surrounding portion 12) surrounds the outside of the open end portion 51a of the can body 51, the upper edge of the open end portion 51a of the can body 51 in the top support member 3 A peripheral wall that hangs down toward the bottom support member 5 from the portion (edge pressing portion 9) that comes into contact with is formed. With this configuration, air is prevented from leaking from the inside of the can through the open end 51a of the can body 51 to the outside. Therefore, a decrease in the internal pressure of the can during molding can be suppressed and the internal pressure can be kept high, unintentional deformation of the can is prevented, moldability is stably increased, and productivity is improved.

In the example shown in FIGS. 5A and 5B, the surrounding portion 12 includes a guide portion 13 and a fitting portion 14. The guide portion 13 is disposed at the end of the surrounding portion 12 on the bottom support member 5 side along the central axis C direction of the top support member 3, and from the top support member 3 to the bottom support member 5 side along the central axis C direction. It has a tapered shape in which the inner diameter gradually increases as it goes to. The fitting part 14 is arrange | positioned between the guide part 13 along the center axis C direction, and the edge holding | suppressing part 9, and the internal diameter is made constant along the center axis C direction.
As shown in FIG. 5A, in the longitudinal sectional view of the top support member 3 including the central axis C, the guide portion 13 (extension line thereof) and the central axis C of the top support member 3 intersect with each other. Among the acute angles and obtuse angles that are used, the acute angle is 10 to 20 °, and is about 15 ° in the example of the present embodiment.

  According to this modification, in addition to the above-described effects, the following effects can be obtained. That is, since the surrounding portion 12 has the tapered guide portion 13, first, the guide portion 13 is reliably extrapolated to the opening end 51 a, and the guide portion 13 causes the central axis C of the top support member 3 and the can to be From the state where the can shaft is coaxially aligned, the fitting portion 14 can be smoothly fitted onto the open end 51a. For this reason, the support state of the open end 51a of the can body 51 by the top support member 3 is stabilized. In addition, since the fitting portion 14 is externally fitted to the opening end portion 51a, a decrease in the internal pressure of the can during molding can be suppressed more effectively, and the internal pressure can be kept high.

Further, in the vertical sectional view of the top support member 3, the acute angle and the obtuse angle formed between the center axis C of the top support member 3 and the guide portion 13 are 10 to 20 °, The guide portion 13 can be reliably and smoothly extrapolated outside the opening end portion 51 a of the can body 51.
Specifically, since the angle is 10 ° or more, when the top support member 3 is moved closer to the opening end 51a of the can body 51, the guide portion 13 is moved with respect to the opening end 51a. It is possible to reliably prevent a problem such as collision and crushing the opening end 51a, and to stably extrapolate the guide portion 13 to the outside of the opening end 51a.
Further, since the angle is 20 ° or less, the inner periphery of the guide portion 13 is easily slidably contacted with the outer periphery of the opening end portion 51a, and the center axis C of the top support member 3 and the can shaft are smoothly centered (coaxially). Centering). That is, since the guide portion 13 can be gently slidably contacted with the opening end portion 51a and gradually centered, the load on the opening end portion 51a can be suppressed to be small, and deformation and the like can be suppressed.

Second Embodiment
Next, a bottom reforming mechanism, a top support member, and a can manufacturing method according to a second embodiment of the present invention will be described with reference to FIGS.
Detailed descriptions of the same components and manufacturing steps as those of the above-described embodiment will be omitted, and only different points will be described below.

  As shown in FIG. 6, the bottle can B of the present embodiment includes a plate blanking process S21, a cupping process (drawing process) S22, a DI process (drawing and ironing process) S23, a trimming process S24, and printing / painting (can outer surface). The can is manufactured through a process S25, a painting (can inner surface) process S26, a necking process S27, a trimming process S28, a screw forming process S29, a curling process S30, a throttle process S31, and a bottom reforming process S32.

  In the present embodiment, unlike the first embodiment described above, a bottom reforming step S32 by a bottom reforming device is provided after steps S27 to S31 which are manufacturing steps by the bottle can manufacturing device. That is, the bottom reforming apparatus is provided in a later process than the bottle can manufacturing apparatus, and the bottom reforming mechanism 21 of the bottom reforming apparatus performs the bottom reforming process on the bottle can B.

  The bottom reforming mechanism 21 presses at least one of the inner peripheral wall 57 and the outer peripheral wall 58 among the annular convex portions 56 of the can bottom 52 of the work can (bottle can) B supplied to the bottom reforming device, At least one of a recess 60 (see FIG. 3) that is recessed radially outward in the inner peripheral wall 57 and a recess (not shown) that is recessed radially inward in the outer peripheral wall 58 is formed.

As shown in FIGS. 7A and 7B, the bottom reforming mechanism 21 has a bottom support member 25 that can move toward and away from the can bottom 52 in the can axis direction and can contact the can bottom 52. While approaching and separating in the can axis direction with respect to the opening end 51a of the can body 51, approaching in the radial direction with respect to the top support member 23 capable of contacting the opening end 51a and the annular convex portion 56 of the can bottom 52 And a pressing portion 26 that forms a recess by pressing at least one of the inner peripheral wall 57 and the outer peripheral wall 58. In the example of this embodiment, the recessed part 60 is shape | molded when the press part 26 presses the inner peripheral wall 57 toward a radial direction outer side.
The central axes C of the bottom support member 25 and the top support member 23 are arranged coaxially with the can axis of the bottle can B to be bottom reformed. Further, the central axis C and the can axis are arranged coaxially with the respective spindle axes of the top spindle 22 and the bottom spindle 24 provided in the bottom reformer.

  The top support member 23 includes an inner fitting portion 28 that fits inside the base portion 53 of the opening end portion 51a of the bottle can B, and an upper end edge (the upper end opening edge of the base portion 53) of the opening end portion 51a. In other words, the curl portion is provided with an edge pressing portion 29 that comes into contact with the can axis direction.

  The inner fitting portion 28 has a substantially columnar shape, and has an outer diameter that is equal to or smaller than the inner diameter of the base portion 53 at the opening end portion 51 a of the bottle can B. The inner fitting portion 28 includes a guide portion 30 and a fitting portion 31. The guide portion 30 is disposed at the end of the inner fitting portion 28 on the bottom support member 25 side along the central axis C direction of the top support member 23, and from the top support member 23 to the bottom support member 25 along the central axis C direction. It has a tapered shape in which the outer diameter gradually decreases toward the side. The fitting part 31 is arrange | positioned between the guide part 30 and the edge holding | suppressing part 29 along the center axis C direction, and the outer diameter is made constant along the center axis C direction.

  As shown in FIG. 7A, in the longitudinal sectional view of the top support member 23 including the central axis C, the guide portion 30 (extension line thereof) and the central axis C of the top support member 23 intersect with each other. Among the acute angles and obtuse angles that are used, the acute angle is 10 to 20 °, and is about 15 ° in the example of the present embodiment.

The edge holding portion 29 has a disc shape and has an outer diameter larger than the outer diameter of the inner fitting portion 28 and the upper edge of the opening end portion 51a of the bottle can B (the curled portion of the base portion 53). doing. An end surface of the end pressing portion 29 facing the bottom support member 25 along the central axis C direction has a ring-shaped planar shape.
When the top support member 23 is moved closer to the bottle can B in the can axis direction and the inner fitting portion 28 is inserted into the opening end portion 51a (the base portion 53) of the can body 51, first, The guide portion 30 is inserted into the opening end portion 51a, and the fitting portion 31 is inserted (fitted) into the opening end portion 51a so as to be guided by the guide portion 30. Then, as shown in FIG. 7B, the end surface of the edge pressing portion 29 comes into contact with the upper edge of the opening end portion 51 a of the bottle can B from above.

  Of the bottom reforming device and the bottom reforming mechanism 21 of the present embodiment, the configurations other than those described above (the top spindle 22, the bottom spindle 24, the bottom support member 25, the pressing portion 26, the link portion 27, etc.) are described above. This is the same as described in the first embodiment.

In the bottom reforming step S32 of the present embodiment, the top support member 23 is brought into contact with the open end 51a (the base 53) of the bottle can B by the bottom reforming device and the bottom reforming mechanism 21, and the bottom support is supported on the can bottom 52. The member 25 is brought into contact, and the inner peripheral wall 57 of the annular convex portion 56 is pressed by the pressing portion 26 to form the concave portion 60.
At this time, the top support member 23 (the edge pressing portion 29) is brought into contact with the upper edge (the curled portion of the base portion 53) of the opening end portion 51a. Further, the top support member 23 (the inner fitting portion 28) is fitted into the opening end portion 51a.

8A and 8B show a modification of the top support member 23 described in this embodiment. In this modification, the top support member 23 includes a bottom support member extending along the central axis C direction of the top support member 23 from the inner fitting portion 28, the end edge pressing portion 29, and the end edge pressing portion 29 (outer peripheral edge thereof). 25, and is formed so as to cover the inner fitting portion 28 from the outside in the radial direction, and the thickness of the upper edge of the opening end portion 51a of the can body 51 between the inner fitting portion 28 and the inner fitting portion 28. (Thickness of the curled portion) and a cylindrical surrounding portion 32 arranged with a gap larger than that. That is, the surrounding part 32 is formed so as to surround the outside of the upper end edge (curl part) of the opening end part 51a. The surrounding portion 32 has an inner diameter that is equal to or larger than the outer diameter of the upper edge of the opening end portion 51a. In the illustrated example, the surrounding portion 32 is disposed with a gap on the radially outer side with respect to the upper end edge of the opening end portion 51a.
In the bottom reforming step S32, the top support member 23 (the surrounding portion 32) surrounds the outside of the upper end edge of the opening end portion 51a.

According to the bottom reforming mechanism 21, the top support member 23, the can manufacturing method of the can, and the modification thereof according to the present embodiment described above, the same operational effects as those of the first embodiment and the modification can be obtained. .
Further, in the present embodiment, the can subjected to the bottom reforming process by the bottom reforming mechanism 21 is the bottle can B. For example, when performing bottom reform processing on a bottle can, if you try to hold the neck part of the bottle can with the top support member, the stroke of the top support member will be as much as the base part is placed above the neck part. Must be set large. On the other hand, according to the present embodiment, the top support member 23 (the edge pressing portion 29) presses the upper edge of the opening end portion 51a of the bottle can B. Therefore, the top support member 23 in the direction of the central axis C. The effect that the stroke L4 can be kept small is particularly remarkable. In the case of the bottle can B, since the curl portion is formed at the upper edge of the opening end 51a of the can body 51 to increase the strength, the top support member 23 is attached to the upper edge. Even if the contact is made directly, there is little risk of deformation or the like in the opening end 51a.

  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, as described below.

In the first and second embodiments described above, in the bottom reforming steps S07 and S32, the pressing portions 6 and 26 of the bottom reforming mechanisms 1 and 21 press the inner peripheral wall 57 of the annular convex portion 56 of the can bottom 52. Although the recess 60 is formed and the bottom reforming process is performed, the present invention is not limited to this.
For example, the pressing portions 6 and 26 may press the outer peripheral wall 58 of the annular convex portion 56 of the can bottom 52 and form the concave portion 60 on the outer peripheral wall 58 to perform the bottom reforming process.
Alternatively, even if the pressing portions 6 and 26 are pressed against both the inner peripheral wall 57 and the outer peripheral wall 58 of the annular convex portion 56 of the can bottom 52, respectively, the concave portions 60 are formed on the inner peripheral wall 57 and the outer peripheral wall 58, respectively. Good.

Further, although the pressing portions 6 and 26 are formed rollers, the present invention is not limited to this. That is, the pressing parts 6 and 26 may be punch claws as described in, for example, Japanese Patent Application Laid-Open Nos. 11-244972 and 2000-197937.
In this case, since the pressing portions 6 and 26 are punch claws, the structure for moving the pressing portions 6 and 26 with respect to the can bottom 52 in the can axis direction and the radial direction can be simplified, and by a simple operation. The concave portion 60 can be quickly formed in the annular convex portion 56.

  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.

  According to the bottom reforming mechanism, the top support member, and the can manufacturing method of the present invention, when the bottom reforming process is performed on the bottom of the can, the stroke of the top support member can be suppressed, and the productivity can be improved. Therefore, it has industrial applicability.

1, 21 Bottom reform mechanism 3, 23 Top support member 5, 25 Bottom support member 6, 26 Pressing portion 8, 28 Inner fitting portion 9, 29 Edge pressing portion 10, 30 Guide portion 11, 31 Fitting portion 12, 32 Surrounding part 51 Can body 51a Open end 52 Can bottom 53 Base part 54 Neck part 55 Dome part 56 Annular convex part (rim)
57 Inner wall (counter part)
58 Perimeter wall (heel)
59 Grounding part (nose part)
60 Recess B Bottle can (can)
C Center axis S02, S22 Cupping process (drawing process)
S03, S23 DI process (drawing and ironing process)
S07, S32 Bottom reform process W0 Blank W1 Cup-shaped body W2 DI can (can)

Claims (11)

In the bottom of the cylindrical can with a can body and a bottom,
A dome that is recessed upward from the bottom of the can along the can axis direction toward the opening end of the can body;
An annular convex portion that is continuous with the outer peripheral edge portion of the dome portion and projects downward from the opening end portion along the can axis direction toward the can bottom side, and extends along the circumferential direction around the can axis And formed,
Pressing at least one of the inner peripheral wall located on the inner side in the radial direction orthogonal to the can axis and the outer peripheral wall located on the outer side in the radial direction of the grounding portion protruding downwards among the annular convex portions. A bottom reforming mechanism for forming a recess,
A top support member capable of contacting the open end,
A bottom support member capable of contacting the can bottom;
A pressing portion that presses at least one of the inner peripheral wall and the outer peripheral wall to form the concave portion, and
The bottom support mechanism according to claim 1, wherein the top support member includes an edge pressing portion that contacts an upper edge of the opening end. The bottom reforming mechanism according to claim 1,
The bottom reforming mechanism, wherein the top support member includes an inner fitting portion that fits inside the opening end portion. The bottom reforming mechanism according to claim 2,
The inner fitting portion is
A tapered guide portion whose outer diameter gradually decreases from the top support member toward the bottom support member side along the central axis direction of the top support member;
A bottom reformer, comprising: a fitting portion disposed between the guide portion along the central axis direction and the edge holding portion, and having a constant outer diameter along the central axis direction. mechanism. The bottom reforming mechanism according to claim 3,
In a longitudinal sectional view of the top support member including the central axis,
The bottom reforming mechanism, wherein an angle formed between the guide portion and the central axis is 10 to 20 °. A bottom reforming mechanism according to any one of claims 1 to 4,
The bottom reforming mechanism, wherein the top support member includes a surrounding portion formed so as to surround the outside of the opening end portion. A bottom reforming mechanism according to any one of claims 1 to 5,
2. The bottom reforming mechanism according to claim 1, wherein the can is a DI can in which the can body has a cylindrical shape. A bottom reforming mechanism according to any one of claims 1 to 5,
The can is a bottle can provided with a neck portion that gradually decreases in diameter toward the opening end of the can body, and a base portion that is continuously provided above the neck portion. A featured bottom reforming mechanism.   A top support member used in the bottom reforming mechanism according to any one of claims 1 to 7. A cupping process of drawing a disk-shaped blank into a cup-shaped body,
While squeezing and squeezing the cup-shaped body to make a bottomed cylindrical can with a can body and a can bottom, on the can bottom,
A dome that is recessed upward from the bottom of the can along the can axis direction toward the opening end of the can body;
An annular convex portion that is continuous with the outer peripheral edge portion of the dome portion and projects downward from the opening end portion along the can axis direction toward the can bottom side, and extends along the circumferential direction around the can axis And drawing and ironing process for forming
Pressing at least one of the inner peripheral wall located on the inner side in the radial direction orthogonal to the can axis and the outer peripheral wall located on the outer side in the radial direction of the grounding portion protruding downwards among the annular convex portions. And a bottom reforming step for forming a recess, and a method for manufacturing a can comprising:
In the bottom reforming process,
A top support member is brought into contact with the opening end,
A bottom support member is brought into contact with the bottom of the can,
Pressing at least one of the inner peripheral wall and the outer peripheral wall with a pressing portion to form the recess,
A method for manufacturing a can, wherein the top support member is brought into contact with an upper edge of the opening end. It is a manufacturing method of the can according to claim 9,
In the bottom reforming process,
A method for manufacturing a can, wherein the top support member is fitted into the opening end. It is a manufacturing method of the can according to claim 9 or 10,
In the bottom reforming process,
A method for manufacturing a can, wherein the top support member surrounds the outside of the opening end.

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