JP2007022617A - Can body, and manufacturing method of can body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a can body which can stabilize a deformed shape at the time of a pressure reduction, and to provide a manufacturing method of the can body. <P>SOLUTION: This can body 10 for pressure reduction has a barrel section 11, and on the barrel section 11, a diameter contracted section 16 which is partitioned by a pair of step sections 14 and 15 and circumferentially extends is formed. The diameter contracted section 16 is formed into a polygonal shape for which a plurality of flat sections 16a circumferentially continue. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a can body for decompression and a method for producing the can body.

In the can for pressure reduction, the filled contents are sealed in a state where the inside is decompressed. Therefore, the trunk portion of the can body in the sealed state is deformed inward in the radial direction. However, for example, due to the rolling direction of the metal plate forming the can body, variation in the distribution of the composition, etc., it is difficult to dent the torso uniformly over the entire circumference. When the strength is low, such as when the thickness of the material is low, there is a possibility that a locally deeply recessed portion may be formed or may break in some cases.
For this reason, various cans suitable for decompression have been proposed.

For example, as shown in Patent Document 1 below, the body portion has a pair of lateral ribs projecting radially outward with respect to the circumferential surface of the body portion, and multiple surfaces provided between the lateral ribs. A configuration including a shape portion is known. Thereby, when the inside of the can body is decompressed and the polyhedral shape portion of the body portion is mainly recessed inward in the radial direction, the recess is formed by the lateral ribs to form the polyhedral shape of the body portion. It is prevented from propagating to the portions that are continuous to the upper and lower portions in the can axis direction.
JP 11-91772 A

However, in the conventional can body, the propagation of the dent is blocked by the lateral ribs, so that a large internal stress may be accumulated depending on the circumferential position of the lateral ribs. Therefore, a portion that is locally bent radially inward may be formed in the lateral rib, and the deformation of the multi-surface shaped portion is caused to be upward or downward in the can axis direction of the multi-surface shaped portion via the portion. In some cases, it was propagated to the connected parts. In this case, wrinkles or dents may be generated in the continuous portion of the body portion, or in some cases, the body portion may be broken. That is, there is a problem that it is difficult to stabilize the deformed shape when the inside of the can body is decompressed.
In addition, since the lateral rib is projected radially outward with respect to the circumferential surface of the body portion, when the can body is transported, adjacent can bodies collide with each other, and the lateral rib There was also a risk of crushing.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a can body and a method for manufacturing the can body that can stabilize the deformed shape at the time of decompression.

  In order to solve such problems and achieve the above-mentioned object, the can body of the present invention is a decompression can body having a body portion, and a pair of step portions extending in the circumferential direction on the body portion The diameter-reduced portion defined by the step is formed, and the diameter-reduced portion has a polyhedral shape in which a plurality of plane portions are connected in the circumferential direction.

According to this invention, since the reduced diameter portion is defined by the pair of stepped portions, when the inside of the can body is depressurized and the flat portion is deformed radially inward, the trunk portion Of these, a portion (hereinafter referred to as “peripheral portion of the step portion”) connected to the step portion in a portion where the reduced diameter portion is not formed, and the step portion are caused to follow the deformation of the planar portion in the radial direction. It can be deformed inward. Therefore, when the inside of the can body is depressurized, it is possible to suppress accumulation of internal stress in the stepped portion and the peripheral portion of the stepped portion. As a result, it is possible to prevent the stepped portion and the peripheral portion of the stepped portion from being locally greatly deformed, such as being bent radially inward.
From the above, it is possible to provide a can body that has a stable deformed shape during decompression.

Here, the stepped portion may be gradually reduced in diameter from the peripheral portion of the stepped portion toward the reduced diameter portion.
In this case, the above-described effects can be reliably achieved, and since there is no portion projecting outward in the radial direction in the body portion, it is possible to prevent deterioration in the transportability and handleability of the can body.

  The portion corresponding to the reduced diameter portion is the enlarged diameter portion having the largest diameter in the body portion, and the portion corresponding to the stepped portion is gradually enlarged toward the enlarged diameter portion. In the structure of the can body thus formed, when the inside thereof is depressurized, the central portion in the can axial direction of the enlarged diameter portion is easily deformed radially inward, but both ends in the can axial direction are Such deformation is less likely to occur. That is, the stepped portion that is gradually enlarged toward the diameter-enlarged portion acts as a rib that resists deformation toward the radially inward direction due to the reduced pressure. Therefore, when the inside of the can body is depressurized, there is a possibility that a portion in which a large internal stress is locally accumulated is generated at both ends of the stepped portion and the enlarged diameter portion in the can axis direction. The shape cannot be stabilized.

  Further, the method for manufacturing a can according to the present invention includes forming a barrel portion by drawing and ironing a metal plate, and then reducing the diameter of the portion excluding one end portion of the barrel portion. The step portion is formed, and thereafter, the other end portion of the barrel portion is subjected to diameter expansion processing to form the other step portion, and among the inner peripheral surface of the barrel portion, the pair of step portions is used. The defined portion is pressed radially outward at a plurality of locations spaced in the circumferential direction to form a reduced diameter portion having the flat portion.

  According to the present invention, it is possible to provide a can body having a stable deformed shape at the time of decompression.

Embodiments of the present invention will be described below with reference to the drawings.
The can body 10 of the present embodiment is formed of a metal such as an aluminum alloy, for example, and is provided with a trunk portion 11 and a shoulder portion that is continuously connected to the upper end portion of the trunk portion 11 in the can axis O direction and is gradually reduced in diameter toward the upper side. 12 and a base part 13 that is connected to the upper end of the shoulder 12 in the can axis O direction and extends upward. The base portion 13 is formed with a male screw portion 13a to which a cap (not shown) is screwed.

  The body portion 11 is formed with a reduced diameter portion 16 defined by a pair of step portions 14 and 15 extending in the circumferential direction, and the reduced diameter portion 16 has a polyhedral shape in which a plurality of planar portions 16a are continuous in the circumferential direction. ing. The stepped portions 14 and 15 are gradually reduced in diameter toward the reduced diameter portion 16, and the reduced diameter portion 16 of the body portion 11 is positioned most radially inward and the thickness thereof is reduced. In the present embodiment, six plane portions 16a are provided, and the reduced diameter portion 16 has a six-face shape. Further, the step portions 14 and 15 extend over the entire circumference of the trunk portion 11.

Next, a method for manufacturing the can 10 configured as described above will be described.
First, after drawing and ironing a metal plate to form a bottomed cylindrical body 20 having a body 11 and a bottom 17, as shown in FIG. 2 (a), one end of the body 11 is The removed portion, in this embodiment, the portion excluding the bottom 17 side is subjected to diameter reduction processing to form one step portion (hereinafter referred to as “lower step portion”) 14 as shown in FIG.

  Next, the other end portion of the trunk portion 11, in this embodiment, the opening portion 21 side is subjected to diameter expansion processing, and as shown in FIG. 2C, the other step portion (hereinafter referred to as “upper step portion”) 15. And a portion defined by the lower step portion 14 and the upper step portion 15 on the inner peripheral surface of the body portion 11 is formed at a plurality of positions spaced in the circumferential direction to have a total length in the direction of the can axis O. As shown in FIG. 2D, the reduced diameter portion 16 having a plurality of flat portions 16a is formed.

  Thereafter, the opening 21 of the bottomed tubular body 20 is subjected to neck-in processing to form a shoulder 12 and a pre-clasp portion 13 b that is connected to the upper end of the shoulder 12 and has a smooth inner and outer peripheral surface. Then, the male cap portion 13b shown in FIG. 1 is formed by forming the male screw portion 13a and the like by forming the cap portion 13b by subjecting the pre cap portion 13b to a screw forming process or the like.

  Here, the plane portion 16a is formed using a hexagonal mold in plan view that is supported so as to be able to advance and retreat in the direction of the can axis O of the bottomed cylindrical body 20 arranged. That is, in the process in which the mold moves forward inside the bottomed cylindrical body 20 in the direction of the can axis O toward the bottom portion 17, the six top portions constituting the hexagonal shape are the inner periphery of the body portion 11. The plane portion 16a is formed by sequentially pressing the portion defined by the lower step portion 14 and the upper step portion 15 from the upper side toward the lower side.

  As described above, according to the can body 10 according to the present embodiment, since the reduced diameter portion 16 is defined by the pair of step portions 14 and 15, the inside of the can body 10 is decompressed and the flat portion 16a has a diameter. When deformed inward in the direction, a portion (hereinafter referred to as “peripheral portion of the step portion”) 11a connected to the step portions 14 and 15 in the portion of the body portion 11 where the reduced diameter portion 16 is not formed. The step portions 14 and 15 can be deformed radially inward following the deformation of the flat portion 16a. Therefore, when the can 10 is depressurized, it is possible to suppress accumulation of internal stress in the step portions 14 and 15 and the peripheral portion 11a of the step portion.

As a result, it is possible to prevent the portions 14 and 15 and the peripheral portion 11a of the steps from being locally greatly deformed, such as being bent radially inward.
From the above, it is possible to provide the can body 10 with a stable deformed shape at the time of decompression.

  Further, since the stepped portions 14 and 15 are gradually reduced in diameter from the peripheral portion 11a of the stepped portion toward the reduced diameter portion 16, there is no portion projecting radially outward in the body portion 11. It is possible to prevent a decrease in the transportability and handling properties of the can body 10.

  The portion corresponding to the reduced diameter portion 16 is the enlarged diameter portion having the largest diameter in the body portion 11, and the portions corresponding to the step portions 14 and 15 are directed toward the enlarged diameter portion. In the structure of the can body that is gradually expanded in diameter, when the inside is depressurized, the center part in the can axis direction of the enlarged diameter part is easily deformed radially inward, but both ends in the can axis direction. Such a portion is less likely to be deformed. That is, the stepped portion that is gradually enlarged toward the diameter-enlarged portion acts as a rib that resists deformation toward the radially inward direction due to the reduced pressure. Therefore, when the inside of the can body is depressurized, there is a possibility that a portion where a large internal stress is locally accumulated at both ends of the stepped portion and the enlarged diameter portion in the can axis direction. It cannot be stabilized.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the embodiment, a so-called bottle can is shown as the can body 10, but a can in which a can lid is wound may be adopted.

  Provided is a can body capable of stabilizing a deformed shape during decompression.

It is a schematic structure figure of a can shown as one embodiment concerning the present invention. It is process drawing which shows the manufacturing method of the can shown as one Embodiment which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Can body 11 Trunk part 14, 15 Step part 16 Reduced diameter part 16a Plane part

Claims (2)

A can body for decompression having a body part,
A reduced diameter portion defined by a pair of stepped portions extending in the circumferential direction is formed in the body portion, and the reduced diameter portion has a polyhedral shape in which a plurality of planar portions are continuous in the circumferential direction. Can body. It is a manufacturing method of the can object according to claim 1,
After the metal plate is subjected to drawing and ironing to form a body portion, the portion excluding one end portion of the body portion is subjected to diameter reduction processing to form one stepped portion, and then the body portion The other end portion is subjected to diameter expansion processing to form the other stepped portion, and a portion defined by the pair of stepped portions of the inner peripheral surface of the body portion is spaced apart in the circumferential direction. A can manufacturing method characterized by forming a reduced diameter portion having the flat portion by pressing outwardly in a plurality of locations.

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