JP5887340B2 - Threaded bottle can manufacturing method and manufacturing apparatus - Google Patents

Description

The present invention relates to a manufacturing method and a manufacturing apparatus for a bottled can having a screw to which a cap is screwed.
This application claims priority based on Japanese Patent Application No. 2011-093085 for which it applied to Japan on April 19, 2011, and uses the content here.

As a container filled with contents such as a beverage, a bottle-shaped can (bottle can) made of an aluminum alloy, in which a cap is screwed to a cap portion having a male screw, is known.
As disclosed in Patent Document 1 or Patent Document 2, this bottle can has a bottomed cylindrical body in which a bottom plate portion and a cylindrical side surface portion are integrated by drawing and ironing (DI molding) of an aluminum alloy plate. After forming the shoulder portion by reducing the diameter of the opening and forming a cylindrical portion with an enlarged diameter for screw molding above the shoulder portion, the cylindrical portion is screw-molded. The curled portion forming process is performed on the opening end portion.

In addition, this type of bottle can is coated on the inner and outer surfaces of the bottomed cylindrical body before processing by reducing the diameter of the opening, but the opening is processed without particularly damaging the inner surface coating. As a method, there is a method described in Patent Document 3.
In Patent Document 3, in the intermediate formed body before thread forming, the mouth is formed by drawing at least two steps from the shoulder portion, so that the screw is formed at the second step portion from the opening end. It is described that a cylindrical part having an intermediate diameter between a peak diameter and a valley diameter is formed, and this cylindrical part is sandwiched between an inner piece and an outer piece and screw-formed.

US Pat. No. 5,704,240 JP-A-5-229545 JP 2002-66674 A

According to the method described in Patent Document 3, since the outer diameter of the cylindrical portion before the screw forming process is formed to be an intermediate diameter between the thread crest diameter and the valley diameter, the plastic deformation due to the screw forming process is small. The paint damage can be expected to be reduced.
By the way, this kind of bottle can can be sealed with a cap again after opening, but it is also required that this sealing operation is easy.

  The present invention has been made in view of such circumstances, and is capable of being thread-formed without damaging the inner surface coating, and also has a method for producing a threaded bottle can with improved seal operability. An object is to provide a manufacturing apparatus.

As a result of earnest research on the sealing operation again after opening the inventor, the lowest end of the thread on the inner surface side of the cap is in the valley between the first and second threads of the bottle can screw. It was thought that the sealing operation can be facilitated if it is screwed smoothly. On the other hand, in the method described in Patent Document 3, the outer diameter of the cylindrical portion before the screw forming process is formed to an intermediate diameter between the thread crest diameter and the valley diameter, and the screw forming process is performed at the position of the intermediate diameter. Therefore, in the taper part (particularly the part before the screw start part) from the curl part to the first round of the first thread of the screw, an unprocessed part having an outer diameter larger than the thread root diameter remains. Therefore, it has been found that this unprocessed portion serves as a resistance when the cap is sealed again.
Therefore, in order to facilitate the sealing operation again, it is possible to perform thread forming so that a portion larger than the root diameter of the screw does not remain in the tapered portion extending from the curled portion to one round of the first thread of the screw. We came to the conclusion that it was important and decided to use the following solutions.

The method for manufacturing a threaded bottle can according to the present invention reduces the diameter of the opening of the bottomed cylindrical body to form a shoulder, and above the shoulder, between the crest diameter and the trough diameter. And an inner piece that is in contact with the inner peripheral surface of the cylindrical portion, and a tapered portion that gradually decreases in diameter from the upper end of the cylindrical portion toward the opening end. the tubular portion sandwich the by an outer frame which is brought into contact with the outer peripheral surface and, together with the screw formed into the cylindrical portion, and diameter reduction by the outer piece of the position of the front of the thread-starting portion, In the position before the screw start portion, the outer diameter of the portion from the upper edge of the first thread of the screw formed in the cylindrical portion to a part of the taper portion is the same as the valley diameter of the screw, It is characterized by processing to a smaller diameter.

According to the manufacturing method of the present invention, the outer diameter of the cylindrical portion is formed to be an outer diameter between the thread crest diameter and the trough diameter, and above the upper edge of the first thread at the time of thread forming. When the cap is re-sealed by molding the part to be positioned to the outer diameter that is the same as or smaller than the thread root diameter, the cap is put on and the bottom end of the thread inside the cap is It is possible to reduce the resistance between the screw start portion and the next peak portion until it is guided to the valley portion.
Moreover, since the cylindrical part before screw forming is formed in the outer diameter between a screw thread diameter and a valley diameter, the amount of plastic deformation at the time of a process becomes small. In addition, the outer diameter of a cylindrical part should just be set between the thread diameter and the valley diameter, and does not necessarily need to be an intermediate diameter.

The apparatus for producing a threaded bottle can according to the present invention reduces the diameter of the opening of the bottomed cylindrical body to form a shoulder, and above the shoulder, between the crest diameter and the trough diameter. A device for subjecting the cylindrical portion of the intermediate formed body to a screw forming process to a cylindrical portion having an outer diameter and a tapered portion that gradually decreases in diameter from the upper end of the cylindrical portion toward the opening end. The cylindrical portion is sandwiched between the inner piece that is in contact with the inner peripheral surface of the cylindrical portion and the outer piece that is in contact with the outer peripheral surface, and the inner piece and the outer piece are connected to the intermediate piece. A screw is formed in the tubular part by rotating around the axis of the molded body, and the inner piece and the outer piece are for forming a screw for forming a screw in the tubular part. the convex portion and the screw forming recess is helical and together are formed respectively in the corresponding shapes, the outer piece is hand than thread-starting unit The location, the outer peripheral renovation unit for diameter reduction of the position of the front of the said thread-starting portion, continuous with the thread forming projection disposed above the pile eye screw is formed in the tubular portion Te, the screw-forming convex part and either the same diameter, characterized in that it kicked set it than the diameter.

The bottle can of the present invention is a bottle can manufactured by the manufacturing method of the present invention.
In the bottle can of the present invention, the maximum outer diameter of the portion from the lower edge of the taper portion below the curl portion formed at the opening end to the upper edge of the first thread of the screw is the first thread of the screw. It is preferable that the outer diameter is the same as or smaller than the thread valley diameter of the adjacent valley portion.

  According to the present invention, since the portion from the lower edge of the taper portion to the upper edge of the first thread of the screw is prevented from being larger than the root diameter of the screw, the cap is put on when the cap is sealed again. In addition, it is possible to reduce the resistance until the lowermost end of the screw thread inside the cap is guided to the trough between the screw start portion of the bottle can and the next peak portion, and it is easy to perform the sealing operation again. Can be. In addition, the amount of plastic deformation during screw forming is small, and even in the first thread, there is little restriction on the material flow during forming, so damage to the inner surface coating can also be suppressed.

It is a front view of the cylindrical part vicinity which shows the intermediate molded object in the middle of manufacture in one Embodiment of this invention. It is sectional drawing of the principal part which shows the formation process of the intermediate molded object of the bottle can of FIG. 1 in order of (a)-(d). It is sectional drawing which shows the punch which expands an opening part. It is sectional drawing which shows the shaping | molding tool for die necking which reduces an opening part. FIG. 2 shows a state where an intermediate molded body of the bottle can of FIG. 1 is subjected to screw forming processing, and (a) shows a state in which an inner piece and an outer piece are arranged inside and outside of the bottle can and before the screw start portion. The longitudinal cross-sectional view of the position equivalent to a part is (b), and the longitudinal cross-sectional view of the same position as (a) which shows the state in which the bottle can is pinched by the inner piece and the outer piece. It is a front view near the base part showing the bottle can of one embodiment. It is sectional drawing which shows the relationship between the bottle can and cap of one Embodiment, The left half shows the state which screwed the cap to the bottle can, and the right half showed the state which put the cap on the bottle can before screwing, respectively. Yes. It is sectional drawing similar to FIG. 7 which shows the relationship between the conventional bottle can and a cap.

Hereinafter, an embodiment of the present invention will be described.
The bottle can 1 is made of a thin metal plate of aluminum or aluminum alloy, and a shoulder portion 2 that gradually decreases in diameter upward is formed on a bottomed cylindrical can body portion (not shown) as shown in FIG. A small-diameter neck 3 is formed at the upper end of the shoulder 2, a base 4 is formed at the upper end of the neck 3, a screw 5 is formed on the outer periphery of the base 4, and a cap skirt below the screw 5. A jaw portion 6 for fixing the end portion is formed, and a curled portion 7 is formed above the screw 5.

In order to manufacture the bottle can 1, the shoulder 2 is formed by reducing the diameter of the opening of the bottomed cylindrical body formed by drawing and ironing (DI molding) a thin plate of aluminum alloy or the like, and then the shoulder 2 is formed. A cylindrical portion 11 having an enlarged diameter for screw forming is formed above the portion 2.
This will be specifically described with reference to FIG. As shown in FIG. 2A, the diameter of the opening of the bottomed cylindrical body is reduced to form the shoulder portion 2, and the cylindrical reduced diameter portion 17 is formed above the shoulder portion 2. This diameter reduction process is a so-called die necking process, and the openings are gradually reduced in diameter by sequentially using molding tools having different diameters, and the shoulder 2 and the diameter reduction shown in FIG. A portion 17 is formed.

  Then, as shown in FIG. 2B, the diameter-reduced portion 17 is expanded again from a position slightly above the upper end of the shoulder portion 2 except for the lower end portion to form a large-diameter portion 18. As shown in FIG. 3, the apparatus for processing the large-diameter portion 18 extends along the can axis direction in the opening (reduced-diameter portion 17) of the bottomed cylindrical body W held by a work holding portion (not shown). The enlarged diameter punch 51 is inserted. Then, the large diameter portion 18 is formed by inserting the large diameter punch 51 into the reduced diameter portion 17 of the bottomed cylindrical body W. By processing the large diameter portion 18, the lower end portion of the reduced diameter portion 17 is expanded. The portion that has not been diameter-processed becomes the neck portion 3.

Next, as shown in FIG. 2C, the small diameter portion 19 is formed by reducing the diameter of the portion above the lower end portion again except for the lower end portion of the large diameter portion 18. This process is a so-called die necking process, and as shown in FIG. 4, the forming tool can be inserted into the opening (large diameter part 18) of the bottomed cylindrical body W held by the work holding part (not shown). An inner die 52 that is inserted along the axial direction and an outer die 53 that is disposed outside the inner die 52 are provided. The outer diameter of the inner die 52 is smaller than the inner diameter of the opening (large diameter portion 18) of the bottomed cylindrical body W before processing, and is formed to have an outer diameter after the diameter reduction. The inner peripheral surface of the outer die 53 is processed. Between the guide surface 54 having an inner diameter for receiving the opening (large diameter portion 18) of the previous bottomed cylindrical body W, the tapered surface 55 for drawing processing for reducing the diameter of the opening, and the outer peripheral surface of the inner die 52. Small-diameter surfaces 56 that form gaps for inserting the reduced-diameter openings are sequentially formed from the tip. Then, the opening (large diameter portion 18) of the bottomed cylindrical body W is press-fitted along the guide surface 54 of the outer die 53, so that the diameter is reduced so as to follow the tapered surface 55, and the opening end is the inner die 52. Is inserted between the outer peripheral surface 52 a of the outer die 53 and the small-diameter surface 56 of the outer die 53 and processed into the small-diameter portion 19. The machining shown in FIG. 2 (a) has a diameter different from that shown in FIG. 4, but a combination of a plurality of types of inner dies and outer dies having the same structure is used.
Due to the processing of the small diameter portion 19, the portion that has not been processed below the small diameter portion 19 becomes the enlarged diameter portion 15. In this case, the small diameter portion 19 is formed to have an outer diameter larger than that of the neck portion 3, and is formed to have an intermediate outer diameter between a valley diameter and a mountain diameter of the screw 5 described later.

Next, as shown in FIG. 4D, the upper half of the small diameter portion 19 is gradually reduced in diameter toward the upper end, and the reduced opening end portion 13 and the tapered portion 14 connected thereto are formed. To do. For this processing, a molding tool for die necking as in FIG. 4 is used. Due to the processing of the opening end portion 13 and the tapered portion 14, the portion that has not been processed below becomes the cylindrical portion 11. Thereby, the intermediate molded body 12 is formed. In addition, the thickness of this cylindrical part 11 is formed to 0.25-0.4 mm.
In the intermediate molded body 12, after the screw 5 is formed on the cylindrical portion 11, the diameter of the opening end portion 13 is further reduced, and the curled portion 7 is formed on the reduced diameter portion. Manufactured.

  In this manufacturing process, as shown in FIG. 1, the intermediate molded body 12 is formed such that the opening end portion 13 has a straight shape corresponding to the dimension necessary for forming the curled portion 7 from the upper end. A tapered portion 14 that gradually increases in diameter downward from the lower end of the taper portion 14 is formed, and a cylindrical portion 11 is formed at the lower end of the tapered portion 14. Most of the cylindrical portion 11 is formed in a straight cylindrical shape except for the lower end portion, and the lower end portion of the cylindrical portion 11 is an enlarged diameter portion 15 having an outer diameter larger than that of the upper portion, and the enlarged diameter portion. The neck portion 3 having a reduced diameter and the shoulder portion 2 having a diameter increasing from the lower end of the neck portion 3 are continuously formed at the lower end of the neck 15.

  In this case, the outer diameter D1 of the open end 13 is smaller than the thread root diameter D2 to be molded, and the outer diameter D3 of the cylindrical portion 11 is the thread diameter except for the enlarged diameter portion 15 at the lower end. It is set to an intermediate diameter between D4 and the thread root diameter D2. For example, when the thread diameter D4 is 37 mm, the thread valley diameter D2 is 36.3 mm, and the distance between the first and second threads is 2.5 mm to 4.5 mm, the diameter of the cylindrical portion 11 is increased. The outer diameter D3 excluding the portion 15 is set to 36.5 mm to 36.8 mm. Further, the tapered portion 14 that communicates between the cylindrical portion 11 and the open end portion 13 has an inclination angle θ of 20 ° to 40 ° with respect to the can axis direction, and a length H along the can axis direction of 2. .6 to 4.0 mm is set.

Next, a description will be given of a threaded bottle can manufacturing apparatus 100 for forming the screw 5 on the intermediate molded body 12. The manufacturing apparatus 100 touches the inner peripheral surface of the cylindrical portion 11 of the intermediate molded body 12. It has an inner piece 21 in contact with it and an outer piece 22 in contact with the outer peripheral surface. As shown in FIGS. 1 and 5, the inner piece 21 and the outer piece 22 are spirally formed with screw-forming convex portions 23 and 24 and screw-forming concave portions 25 and 26 for forming the screw 5 on the outer peripheral surface thereof. And the inner piece 21 and the outer piece 22 are moved in the radial direction so that the cylindrical portion 11 of the intermediate molded body 12 is sandwiched between the concave and convex portions. The screw 5 is formed in the cylindrical portion 11 by rotating around the axis of the intermediate molded body 12. At this time, the jaw 6 disposed below the screw 5 is also processed at the same time.
Further, the outer piece 22 has the same diameter as that of the screw-forming convex portion 24, which is continuous with the screw-forming convex portion 24 arranged on the upper side of the first mountain of the screw 5 formed in the cylindrical portion 11. An outer peripheral reforming portion 27 having a larger diameter is provided. The inner piece 21 is formed such that a portion continuous with the screw forming recess 25 disposed on the upper side of the first mountain of the screw 5 has the same diameter as the screw forming recess 25 or a smaller diameter than that. An outer periphery reforming portion 27 of the outer piece 22 serves as a relief portion 28 when the cylindrical portion 11 and the tapered portion 14 are formed.

The screw forming by the inner piece 21 and the outer piece 22 will be described in detail with reference to FIG.
The shape of the screw 5 will be described in advance. As shown in FIG. 6, the screw 5 is an incomplete screw whose height gradually increases until the height of the crest 31 reaches a predetermined dimension. The portion 32 is present, and the screw start portion 33 is a portion having a height about half the height of the peak portion 31 in the incomplete screw portion 32. Moreover, the height of the peak part 31 means the average value of the maximum value in the radial direction between the peak part 31 and the valley part 34 adjacent to the peak part 31, and the thread diameter D4 is outside the peak part 31. The diameter and thread valley diameter D2 refer to the outer diameter of the valley portion 34.
Note that the screw forming process does not necessarily start from the screw start portion 33 but is processed from an arbitrary position.

FIG. 5 shows a longitudinal cross-sectional view of the position before the screw start portion 33 after the screw forming process, and is a cross-sectional view of the position before the first thread of the screw is wound around one turn and becomes the second thread. is there.
FIG. 5A shows a state in which the inner piece 21 is inserted inside the tubular portion 11 of the intermediate molded body 12 and the outer piece 22 is disposed radially outward of the tubular portion 11 so as to face each other. (B) has shown the state which the inner piece 21 and the outer piece 22 approached, and pinched the cylindrical part 11 from the middle of the taper part 14. FIG. For the sake of convenience, FIG. 5 (a) shows half of the inner piece and the outer piece viewed from the front, and the other half shows only the outline, but FIG. 5 (b) shows only the outline for both the inner piece and the outer piece. .
In the cross section of FIG. 5, the position of the alternate long and short dash line is A for the first thread of the screw (the screw thread in front of the second thread after winding for one turn), and B for the position of the valley above it. To do.

  As shown in FIG. 5A, the bent portion 16 between the tubular portion 11 and the tapered portion 14 is disposed at the position of the outer peripheral reforming portion 27. When both pieces 21 and 22 approach from the state shown in FIG. 5A and the cylindrical portion 11 is sandwiched and screw forming is performed, as shown in FIG. The outer diameter of the portion extending from the upper edge of the first thread of the formed screw to a part of the tapered portion 14 is reduced by the outer peripheral reforming portion 27, so that the outer diameter is the same as the valley diameter D2 of the screw. The maximum outer diameter of the cylindrical portion 11 and the tapered portion 14 is the same as or smaller than the thread root diameter D2.

After the thread forming process in this manner, the bottle can 1 is manufactured by curling the opening end portion 13 to form the curled portion 7.
The cap 41 that covers the bottle can 1 has a circular top plate portion 42 and a cylindrical skirt portion 43. After the cap 41 is covered with the cap portion 4 of the bottle can 1, the skirt of the cap 41 is covered by a capping roll. By forming the portion 43 so as to follow the screw 5 of the base portion 4, a thread 44 is formed on the skirt portion 43 and screwed to the base portion 4, and the lower end portion 45 of the skirt portion 43 is connected to the jaw portion. As shown in the left half of FIG. 7, the cap 41 and the bottle can 1 are fixed in a screwed state. Since the cap 41 is screwed onto the screw 5 of the cap part 4 in this way, the inner diameter of the thread 44 of the cap 41 is matched with the thread valley diameter D2 of the cap part 4. In addition, regarding this cap, when each part is shown, it demonstrates using the same code | symbol before and after screw formation.

Next, a case where the cap 41 is opened and then sealed again will be described.
When the cap 41 is rotated so as to be loosened from the screwed state shown in the left half of FIG. 7, the slit 46 formed in the skirt portion 43 breaks from the lower end 45 and the upper portion thereof, and the lower end Is left on the jaw 6 in a band shape, and its upper part can be removed from the base 4.

  Next, when the removed cap 41 is put on the base part 4 for sealing again, the lowermost end of the thread 44 on the inner peripheral surface of the cap 41 is the tapered part of the base part 4 as shown in the right half of FIG. 14 descends while sliding on 14 and comes into contact with the upper surface of the first thread of the screw 5. At this time, by rotating the cap 41 to the right, the lowermost end of the thread 44 is guided along the upper surface of the first mountain to the entrance of the valley 34 below.

  As described above, the taper portion 14 above the first thread of the screw 5 has a maximum outer diameter that is the same as or smaller than the thread valley diameter D2. The thread 44 is less likely to receive resistance from the cylindrical portion 11 and the tapered portion 14, smoothly reaches the top surface of the first mountain, and then easily guides to the entrance of the valley 34 below the first mountain. Can do. Then, by rotating the cap 41, the lowest end of the thread 44 can be advanced into the valley 34 and screwed in.

Incidentally, the conventional bottle can will be described with reference to FIG. 8. In the conventional bottle can, the portion 62 larger than the thread valley diameter D2 remains in the tapered portion 61 above the first mountain, and therefore when the cap 41 is sealed again. The degree of contact of the thread 44 of the cap 41 with the portion 62 larger than the thread root diameter D2 is large, and the resistance when closing the screw is large, so that it is difficult to perform the sealing operation again.
Reseal torque when re-sealing the cap while holding the bottle can on a digital torque meter manufactured by Nidec Sympo Co., Ltd. (When the cap is put on the cap part and the sealing operation is performed, the liner on the top of the cap The resistance value generated until the curled portion comes into contact with the top surface was measured. As a result, it was 0.2 N · cm in the bottle can according to the embodiment of the present invention, but was 8.7 N · cm in the conventional bottle can. It was.
Thus, the bottle can 1 manufactured by the manufacturing method of the present invention has a portion (the cylindrical portion 11 and the tapered portion 14) located above the upper edge of the first mountain of the screw 5 is the same as the thread valley diameter D2. Or, since it is formed smaller than the thread root diameter D2, it is possible to facilitate the sealing operation again.

In addition, this invention is not limited to the thing of the structure of the said embodiment, In a detailed structure, it is possible to add a various change in the range which does not deviate from the meaning of this invention.
The outer diameter of the cylindrical portion is set to an intermediate diameter between the thread diameter and the valley diameter, but may be set to the same outer diameter as the thread diameter or the same outer diameter as the valley diameter. What is necessary is just to be set to the outer diameter between diameters.

  INDUSTRIAL APPLICABILITY The present invention can be applied as a manufacturing method and a manufacturing apparatus for a threaded bottle can that is filled with various beverages such as coffee beverages and whose cap can be easily resealed.

DESCRIPTION OF SYMBOLS 1 Bottle can 2 Shoulder part 3 Neck part 4 Cap part 5 Screw 6 Jaw part 7 Curl part 11 Cylindrical part 12 Intermediate molded object 13 Open end part 14 Taper part 15 Diameter-expanding part 16 Bending part 21 Inner piece 22 Outer piece 23,24 Thread forming convex part 25, 26 Thread forming concave part 27 Outer peripheral reforming part 28 Escape part 31 Mountain part 32 Incomplete thread part 33 Screw starting part 34 Valley part 41 Cap 42 Top plate part 43 Skirt part 44 Screw strip 45 Lower end part 46 Slit 100 Threaded bottle can manufacturing equipment

Claims (2)

The opening of the bottomed cylindrical body is reduced in diameter to form a shoulder, and above this shoulder, a cylindrical portion having an outer diameter between the thread ridge diameter and the valley diameter, and the cylindrical shape A tapered portion that gradually decreases in diameter from the upper end of the portion toward the opening end, and an inner piece that is in contact with the inner peripheral surface of the cylindrical portion and an outer piece that is in contact with the outer peripheral surface sandwiching the tubular part, with screws formed into the cylindrical portion, the front position than thread-starting portion and diameter reduction by the outer frame, at a position nearer than the thread-starting portion, the The outer diameter of the portion extending from the upper edge of the first thread of the screw formed in the cylindrical portion to a part of the tapered portion is processed into a diameter that is the same as or smaller than the root diameter of the screw. A manufacturing method of a bottle can with a screw. The opening of the bottomed cylindrical body is reduced in diameter to form a shoulder, and above this shoulder, a cylindrical portion having an outer diameter between the thread ridge diameter and the valley diameter, and the cylindrical shape An apparatus for subjecting the cylindrical portion of the intermediate molded body formed with a tapered portion that gradually decreases in diameter from the upper end of the portion toward the opening end portion to a screw forming process, the inner peripheral surface of the cylindrical portion By sandwiching the cylindrical portion by an inner piece abutted on the outer piece and an outer piece abutted on the outer peripheral surface, and rotating the inner piece and the outer piece about the axis of the intermediate molded body, The cylindrical part is configured to form a screw, and the inner piece and the outer piece have a screw forming convex part and a screw forming concave part for forming a screw in the cylindrical part, and together are formed in a shape corresponding to each other, the outer piece is in a position nearer than thread-starting portion, in front of than the thread-starting unit Periphery remodeling unit which diametral reduction to location is, in succession thread forming projection disposed above the pile eye screw is formed in the cylindrical portion, or the the said thread forming projection diameter , threaded bottle can manufacturing apparatus characterized by being kicked set it than the diameter.

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