JP2008062279A - Method for forming can body with rib - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming a bottomed cylindrical can body formed with ribs on the outer surface using aluminum material, the method effectively preventing the development of pin hole. <P>SOLUTION: A female die 8 having an almost circular cross section and formed with a plurality of lines of grooves 7 on the inner peripheral surface is formed on a pressing die 6, and after a pellet 9 of the aluminum material is arranged on the bottom of the female die 8, the pellet 9 is pressed with a columnar punch 10 having an outer diameter slightly smaller than the outer diameter of the female die 8, in the female die 8. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a double can such as a gas cartridge for supplying gas mainly for a tool for driving a fastener such as a nail or a screw, and a can having a rib for raising a rib on the inner can or the outer can. The present invention relates to a body molding method.

  An inner can as an inner container filled with liquefied gas is disposed inside an outer can which is an outer container, and further provided with a multiple structure filled with compressed high-pressure gas in the inner space between the inner and outer cans. A gas cartridge (two-chamber pressure filling device) having a structure in which the gas in the inner can is released (injected) by compressing and deforming using the pressure of the high-pressure gas filled in the inner space has been conventionally used. Known from.

  Furthermore, as the above-mentioned gas cartridge, the outer can and the inner can are made of aluminum, and the inner can is easily deformed by the pressing force of the high pressure gas, and the internal gas is not easily transmitted to the outside. A deformable thin-walled aluminum container is preferred (see Patent Document 1).

  By the way, the release of the content gas in the above-described multi-structure container of the gas cartridge is performed by compressing the inner can by the pressure of the high pressure gas filled in the inner space of both the inner and outer cans and deforming the recess. The deformation of the inner can using pressure is a free deformation, and it does not deform evenly. In the initial stage of deformation of the inner can, the weakly rigid portion is compressed and dent-deformed, and the deformation of this portion is further promoted. Therefore, in many cases, only one place is greatly dented and deformed.

  Since the opening and bottom of the outer can and the inner can are highly rigid and difficult to deform, stress concentration occurs in a part of the central part, and only the part that was initially deformed further deforms further, so this part Wrinkles and creases occur, cracks and pinholes occur. If cracks or pinholes occur in the inner can, the high-pressure gas filled in the inner space of both the inner and outer cans will flow into the inner can, and the high-pressure gas will also be released (injected) when the content gas is released (injected). The pressure difference between the inner and outer cans decreases, the content gas is not sufficiently released to the outside, and the function as a gas can is lost while the gas remains.

Then, like patent document 1, providing a deformation | transformation induction | guidance | derivation part between an outer can and an inner can (inner bag) is considered so that an inner can deform | transforms equally. The following means are considered as means for inducing deformation.
(1) A separate frame member is disposed between the inner and outer cans, and only the portion where the frame member is disposed is deformed during gas filling.
(2) The outer can is crushed at equal intervals, and the inner can is deformed by the crushed portion.
(3) The inner can is deformed in advance.
Japanese Patent No. 2873691

  However, the means (1) increases the cost, and the means (2) requires a processing step of crushing a part of the surface of the outer can, and the means (3) is more prone to wrinkles during gas filling. Holes are likely to occur. As you can see, none of them are perfect.

  Therefore, when the rib is set up on the inner can or the outer can and the high pressure gas is filled between the inner can and the outer can, or when the liquefied gas in the inner can is consumed and reduced, the inner can is formed by the rib. It is considered that the shape is deformed.

  For example, when ribs are formed on the inner surface of the outer can, when the inner can is inflated by filling the inner can with the liquefied gas, the portion that hits the rib of the outer can does not deform, so only the other portions Deform. In this way, the ribs that are not easily deformed promote the deformation of the other parts, and the inner can is not deformed in advance, so that it is difficult to make pinholes due to the occurrence of flaws during gas filling. Even when ribs are formed on the outer surface or the inner surface of the inner can, the deformation of other portions is similarly promoted, so that it is not necessary to deform the inner can in advance. Therefore, the same effect can be obtained.

  The present invention was established in view of the above-described problems, and provides a method for forming a can that can form a can having a rib for effectively preventing the occurrence of pinholes. Let it be an issue.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a molding method for forming a bottomed cylindrical can body in which a rib is formed on an outer surface by an aluminum material. After forming a female mold having a plurality of grooves formed on the surface, and placing a pellet of aluminum material on the bottom of the female mold, a cylindrical punch having an outer diameter slightly smaller than the inner diameter of the female mold is formed on the female mold. It is characterized by pressing inside.

  According to a second aspect of the present invention, there is provided a molding method for forming a bottomed cylindrical can body in which ribs are formed on an inner surface with an aluminum material, wherein a female die having a substantially circular cross section is formed in a press die, A plurality of grooves are formed on the outer peripheral surface of a cylindrical punch having an outer diameter slightly smaller than the inner diameter, and an aluminum material pellet is disposed on the bottom of the female mold, and then the punch is pressed in the female mold. It is characterized by that.

  The invention according to claim 3 is characterized in that, in claim 1 or 2, the gap between the female die and the punch and the groove width of the groove are substantially the same.

  According to the first aspect of the present invention, after the press die is formed with the female die having a substantially circular cross section and formed with a plurality of grooves on the inner peripheral surface, and the aluminum pellet is disposed on the bottom of the female die A cylindrical punch having an outer diameter slightly smaller than the inner diameter of the female mold is pressed in the female mold. At this time, since the pellet has no escape space, the pellet rises along the gap between the female die and the punch and the groove formed on the inner peripheral surface of the female die. Then, after the bottom surface of the punch finally stops just before the bottom of the female mold, the punch can be raised to take out the molded product from the female mold, thereby obtaining an inner can in which a plurality of ribs are formed.

  Thus, since the can and the rib can be molded integrally, the cost can be kept low.

  According to the invention of claim 2, a plurality of grooves are formed on the outer peripheral surface of a cylindrical punch having a female die having a substantially circular cross section in the press die and having an outer diameter slightly smaller than the inner diameter of the female die. After the aluminum material pellets are disposed on the bottom of the female die, the punch is pressed in the female die. At this time, since the pellet has no escape, it rises along the gap between the female mold and the punch and the groove formed on the outer peripheral surface of the punch. When the bottom surface of the punch finally stops immediately before the bottom of the female mold, pellets are formed. When the punch is raised and the molded product is taken out from the female mold, an outer can in which a plurality of ribs are formed can be obtained.

  Thus, since the can and the rib can be molded integrally, the cost can be kept low.

  According to a third aspect of the present invention, in the first or second aspect, the gap between the female die and the punch and the groove width of the groove are formed substantially the same. The molding material flows uniformly into the outer can or the inner can of uniform thickness as a whole.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, as shown in FIGS. 1 to 3, the gas cartridge A is for injecting an outer can 1, an inner can 2 arranged inside the outer can 1, and a gas filled in the inner can 2. The cap valve member 3 and the like.

  As shown in FIGS. 2A and 2B, before filling the fuel gas G1 or the high pressure gas G2, the outer can 1 is made of an aluminum cylindrical member having a predetermined diameter and length and a predetermined thickness. One end is opened and the other end is closed. On the other hand, since the inner can 2 is disposed inside the outer can 1, the inner can 2 has an outer shape similar to the outer can 1 in an unfilled state of the gas filled therein, and is smaller than the outer can 1. It consists of a thin aluminum bottomed cylindrical member that is easily deformed.

  By the way, a rib 4 protrudes from the outer peripheral surface of the inner can 2 as a deformation guiding portion.

  Therefore, the state in which the inner can is deformed by gas filling will be described with reference to FIGS. 4 (a), 4 (b), and 4 (c). First, from the state in which the gas is not filled as shown in FIG. When the liquefied fuel gas G1 is filled in the inner can 2 as shown in FIG. 3), the inner can 2 is deformed so as to swell by the pressure during filling, but the rib 4 of the inner can 2 hits the inner surface of the outer can 1. Since the rib 4 cannot obstruct and swell, the concave portion 5 is formed in the inner can 2. FIG. 5 shows this state in cross section. Further, the space S between the bottoms of the outer can 1 and the inner can 2 is filled with the high-pressure high-pressure gas G2. The high pressure gas G2 is used for pressing the surface of the inner can 2 and crushing the inner can 2 to inject the fuel gas G1 to the outside from the injection pipe 3a of the cap valve member 3. Usually, propane, propylene, A gas such as butane is used.

  In the above configuration, when the gas cartridge is used as a driving tool or the like, the valve body 12 is opened by pushing the injection pipe 3a of FIG. The gas inside the can 2 is injected outside. As the gas in the inner can 2 is released, the inner can 2 is crushed by the high pressure gas G2 in the outer can 1, and the pressure in the inner can 2 does not decrease. Then injected. Thus, as the fuel gas G1 in the inner can 2 is consumed, the inner can 2 is crushed and deformed by the high-pressure gas G2, but is formed by the rib 4 as shown in FIG. Deformation is naturally promoted from the deformed recess 5 and proceeds. For this reason, deformation due to pressing is not unevenly distributed in one place and is evenly distributed in three places, so that local stress concentration is avoided, and it is effective that cracks and pinholes due to wrinkles and creases occur. Can be prevented.

  The recess 5 formed in the inner can 2 is not formed in advance, but is formed for the first time by the rib 4 when the fuel gas G1 is filled. Is unlikely to occur. Therefore, it is difficult to make a pinhole.

  In addition, since a separate frame-like member and a special processing step are not required for uniform deformation, the cost can be kept low.

  Next, the basic principle of the molding method for molding the inner can 2 (can body) provided with the rib 4 will be described. As shown in FIG. 6, the press die 6 has a substantially circular cross section and has an inner peripheral surface. A female die 8 having three grooves 7 formed at equal intervals is formed, and an aluminum material pellet 9 is arranged on the bottom of the female die 8, and then the pellet 9 is pressed with a punch 10. The punch 10 is an iron columnar member, and its outer diameter is slightly smaller than the inner diameter of the female die 8.

  When the aluminum pellet 9 arranged on the bottom of the female die 8 is pressed with the punch 10 as shown in FIG. 7A as described above, the pellet 9 has no escape, so as shown in FIG. It grows along the gap between the female die 8 and the punch 10 and the groove 7 formed in the inner peripheral surface of the female die 8. When the bottom surface of the punch 10 finally stops immediately before the bottom of the female die 8, the pellet 9 is formed as shown in FIG. When the punch 10 is raised, the molded product 2a is taken out from the female mold 8, and the upper portion of the rib 4 is cut away, the inner can 2 having the three ribs 4 as shown in FIG. 3 can be obtained.

  The number of grooves 7 in the female mold 8 is not limited to three. Two or four or more may be used. It is good also as a structure which forms a pair of rib 4 in one place like FIG.

  The gap 11 between the female die 8 and the punch 10 and the groove width of the groove 7 are substantially the same. In general, it is preferable that the gap 11 is set to about 0.15 mm and the groove width of the groove 7 is set to about 0.15 to 0.30 mm. The reason is that if the groove width of the groove 7 exceeds twice the gap 11, the molding material (pellet 9) tends to escape toward the groove 7 rather than the gap 11 when pressed.

  The rib of the inner can 2 is not limited to the outer peripheral surface of the inner can. You may form in an internal peripheral surface. In this case, as the gas in the inner can is released, when the inner can is crushed by the high pressure gas G2 in the outer can, the portion provided with the ribs is not easily deformed. This is because the portion is deformed first, and the deformation due to the pressing is not unevenly distributed at one place and is evenly distributed at three places. The molding method for forming the rib on the inner peripheral surface may be the same as the molding method for forming the rib on the inner peripheral surface of the outer can 1 shown below.

  By the way, the rib 4 may be formed on the outer can 1 as a means for uniformly dispersing the deformation caused by the high-pressure gas. That is, in FIG. 9, three ribs 4 are formed along the longitudinal direction at equal intervals in the circumferential direction of the outer peripheral surface of the outer can 1. When the gas is not filled, it is in the state of FIG. 10A, but when the inner can 2 is filled with the fuel gas G1, the inner can 2 swells, as shown in FIG. The rib 4 forms a recess 5 on the outer peripheral surface of the inner can 2.

  Also in this case, the inner can 2 is crushed and deformed by the high-pressure gas G2 as the gas in the inner can 2 is consumed. The deformation due to is evenly distributed in three places, and cracks and pinholes can be effectively prevented from occurring.

  Next, a molding method for molding the outer can 1 (can body) provided with the rib 4 will be described. As shown in FIG. 11, a female die 8 having a substantially circular cross section is formed in a press die 6. After the aluminum material pellets 9 are arranged on the bottom of the female die 8, the pellets 9 are pressed with a punch 10. The punch 10 is an iron columnar member, the outer diameter of which is slightly smaller than the inner diameter of the female die 8, and three grooves 7 are formed at equal intervals on the outer peripheral surface thereof.

  As shown in FIG. 12 (a), when the aluminum material pellet 9 arranged at the bottom of the female die 8 is pressed with the punch 10, the pellet 9 has no escape, so the female die 8 as shown in FIG. 12 (b). The gaps 11 between the punches 10 and the grooves 7 formed on the outer peripheral surface of the punches 10 rise. When the lower surface of the punch 10 finally stops immediately before the bottom of the female die 8 as shown in FIG. By lifting the punch 10 and taking out the molded product 1a from the female mold 8 and performing the necessary processing, the outer can 1 (see FIG. 9) in which the three ribs 4 are formed can be obtained.

  The number of grooves 7 is not limited to three. Two or four or more may be sufficient, or it is good also as a structure corresponding to FIG. 8 and forming a pair of rib in one place.

  The gap 11 between the female die 8 and the punch 10 and the groove width of the groove 7 of the punch 10 are also substantially the same for the same reason as described above. However, the widths of the gap 11 and the groove 7 are set to be larger than those of the inner can 2.

  According to these embodiments, since it is not necessary to provide a special deformation guiding portion between the outer can 1 and the inner can 2, there is no possibility that the outer diameter is increased or the appearance is impaired.

It is a perspective view of the gas cartridge which concerns on embodiment of this invention. (A) is a longitudinal cross-sectional view of the gas cartridge before gas filling, and (b) is a cross-sectional view taken along line XX of (a). It is a disassembled perspective view of the said gas cartridge. It is a cross-sectional view of a gas cartridge, (a) is a gas non-filling state, (b) is after fuel gas filling, (c) is a cross-sectional view in the middle of consumption of fuel gas in the inner can. Longitudinal section of gas cartridge after gas filling It is a perspective view which shows the shaping | molding method of an inner can. (A) is the center longitudinal cross-sectional view which shows the state immediately before shaping | molding of the shaping | molding process of an inner can, (b) is the center longitudinal cross-sectional view which shows the state in the middle of shaping | molding, (c) is the center which shows the final state of a shaping | molding process. It is a cross-sectional view. It is a cross-sectional view of another form of the inner can. It is a disassembled perspective view of the gas cartridge which has the outer can of another form. (A) and (b) are the cross-sectional views before and after filling the gas cartridge of the form of FIG. It is a perspective view which shows the shaping | molding method of the outer can of the said form. (A) is a center longitudinal cross-sectional view which shows the state just before shaping | molding of the shaping | molding process of an outer can, (b) is a center longitudinal cross-sectional view which shows the state in the middle of shaping | molding, (c) is the center which shows the final state of a shaping | molding process. It is a cross-sectional view.

Explanation of symbols

1 Outer can 2 Inner can 4 Rib 7 Groove 8 Female mold 9 Pellet 10 Punch

Claims (3)

In a molding method of molding a bottomed cylindrical can body that forms ribs on the outer surface with an aluminum material,
After forming a female die having a substantially circular cross section in the press die and having a plurality of grooves on the inner peripheral surface, and placing an aluminum pellet on the bottom of the female die, it is slightly smaller than the inner diameter of the female die. A method of forming a can having a rib, wherein a cylindrical punch having an outer diameter is pressed in the female mold. In a molding method of molding a bottomed cylindrical can body in which ribs are formed on the inner surface by an aluminum material,
A female die having a substantially circular cross section is formed in the press die, a plurality of grooves are formed on the outer peripheral surface of a cylindrical punch having an outer diameter slightly smaller than the inner diameter of the female die, and the bottom of the female die is formed. A method for forming a can having a rib, wherein the punch is pressed in the female mold after the aluminum pellets are arranged.   3. The method for forming a can body having a rib according to claim 1, wherein a gap between the female mold and the punch and a groove width of the groove are substantially the same.

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