JP7277232B2 - Barrel and barrel manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a barrel used for storing and transporting alcoholic beverages such as beer and soft drinks, and a method for manufacturing the barrel.

BACKGROUND ART Barrels (kegs) used for storing and transporting alcoholic beverages such as beer and soft drinks are known (see, for example, Patent Document 1). A barrel generally comprises a barrel body made of metal (stainless steel) and a mouthpiece attached to the top of the barrel body.

Conventional barrels include those made by welding and integrating two parts, an upper mirror part and a cylindrical part with a bottom including a barrel and a barrel bottom, and a barrel part that is made by combining the upper mirror part and the barrel. There is known one that is manufactured by welding and integrating three parts, a tubular part forming the barrel and a lower mirror part forming the bottom of the barrel.

The bottomed cylindrical part of the barrel in the two-part form can be produced, for example, by subjecting a metal (stainless steel) plate to cylindrical drawing. From the standpoint of compressive strength, a bottomed tubular part is manufactured using a plate thick enough to match the bottom of the barrel, but in this case, the barrel becomes unnecessarily heavy. In addition, it is preferable to reduce the base area of the barrel because the area occupied by the barrel can be reduced. There is a limit to reducing the bottom area (drawing diameter) and increasing the height (blank diameter) of the bottomed tubular part accordingly.

On the other hand, when the barrel of the latter mode consisting of three parts is adopted, the plate thickness of the cylindrical part forming the barrel can be reduced within a necessary range, and the weight of the barrel can be reduced. In addition, although the lower mirror part forming the barrel bottom is manufactured by cylindrical drawing, the barrel body is a separate part, so there is no need to increase the drawing depth and the bottom area can be reduced. Therefore, in the mode using three parts, the bottom area can be made smaller than in the mode using two parts. However, since the three parts are used in this way, the number of parts and the number of processing steps are increased, resulting in an increase in cost, and the increase in the number of welded portions causes a problem of inferior strength.

JP 2014-237455 A

The present invention has been made in consideration of such points, and it is possible to reduce the weight and the bottom area while suppressing the decrease in strength and the increase in cost. Provide barrels, etc.

The barrel according to the invention comprises:
an upper part;
a lower part;
a body portion provided between the upper portion and the lower portion;
with
The lower portion and the body portion are integrally configured,
A joint is provided between the upper part and the body,
a first thickness of the upper end of the fuselage within a first distance from the joint is substantially the same as the thickness of the upper portion;
A second thickness of the fuselage body portion at a portion farther than the first distance from the joint portion may be thinner than the thickness of the lower portion.

In the barrel according to the invention,
The thickness of the upper portion and the thickness of the lower portion may be substantially the same.

In the barrel according to the invention,
The thickness of the lower portion may be 0.8 to 0.9 times the thickness of the upper portion.

In the barrel according to the invention,
The crystal structure of the body portion may have a higher dislocation density than the crystal structure of the lower portion.

In the barrel according to the invention,
The body body portion may have a crystal structure that has undergone plastic deformation from the crystal structure of the lower portion.

In the barrel according to the invention,
The second thickness of the trunk main body is 0.4 mm to 0.6 mm,
The thickness of the lower portion may be between 0.7 mm and 1.2 mm.

In the barrel according to the invention,
The second thickness of the trunk body portion may be 0.3 times or more and 0.9 times or less of the thickness of the lower portion.

In the barrel according to the invention,
A cross section of the body may be circular with a diameter of 200 mm to 250 mm.

A method for manufacturing a barrel according to the invention comprises:
a first drawing step of drawing to produce a first member having a first depth;
a second drawing step of drawing to produce a second member having a second depth;
A spin processing step of performing spin processing on a portion corresponding to the side surface of the second member to reduce the thickness of a part of the side surface of the second member;
A joining step of joining the first member and the second member that has undergone the spin processing step;
with
The end of the second member on the first member side is not subjected to spin processing, and the thickness of the second member within the range of the first distance from the joint between the first member and the second member may be substantially the same as the thickness of the first member.

In the present invention, when adopting a mode in which the lower part and the body part are integrally configured, and a mode in which the upper part and the body part are joined at a joint part, the lower part and the body part are separately formed. The number of parts can be reduced, and the number of parts to be joined can be reduced as compared with the present embodiment. Therefore, it is possible to prevent the strength from being weakened and the cost from being increased.

In the present invention, when adopting a mode in which the second thickness of the main body portion at a portion farther than the first distance from the joint portion is made thinner than the thickness of the lower portion, the weight of the entire barrel can be reduced. Further, when adopting a mode in which the first thickness of the upper end portion of the body within the range of the first distance from the joint portion is substantially the same as the thickness of the upper portion, it is easy to join the upper portion and the body portion at the joint portion. can be

1 is a side view of a barrel that may be used with embodiments of the present invention; FIG. 1 is an enlarged side view of a barrel that may be used with embodiments of the present invention; FIG. The figure which shows an example of the manufacturing process of the barrel which can be used by embodiment of this invention.

Embodiment <Configuration>
BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments according to the present invention will be described with reference to the drawings.

The barrel of the present embodiment is, for example, a container used for storing and transporting alcoholic beverages such as beer and soft drinks. Although the barrel of the present embodiment is an example of a liquid container, the barrel is used as the liquid container in the following description.

As shown in FIG. 1, the barrel of the present embodiment includes, for example, an upper mirror part 10, a mouthpiece 15 provided in the upper part 10, a lower part 30 which is a barrel bottom, and an upper part Between 10 and lower part 30 there may be a barrel part 20, for example a barrel part. A rubber portion 60 that is an example of an elastic portion may be provided so as to cover the lower portion 30 .

The lower portion 30 and the body portion 20 may be integrally configured to constitute a bottomed tubular component. A joining portion 40 may be provided between the upper portion 10 and the body portion 20 by welding or the like. The first thickness W1 of the upper body portion 21 within the first distance D1 from the joint 40 may be substantially the same as the thickness W0 of the upper portion 10 (see FIG. 2). The second thickness W2 of the fuselage body portion 22 at a location farther than the first distance D1 from the joint portion 40 may be thinner than the thickness W3 of the lower portion 30 . In the present embodiment, “substantially the same” means that the difference between the two is within 5% of the larger value, and the thickness W0 of the upper portion 10≧the first thickness W1 of the upper body end portion 21 In this case, W0−W1≦W0×0.05, and conversely, when the thickness W0 of the joint 40<the first thickness W1 of the body upper end portion 21, W1−W0≦W1×0.05. means. The first distance D1 is for example 10 mm to 20 mm, typically 15 mm.

As shown in FIG. 2 , a first thickness change region 26 having a varying thickness may exist between the trunk upper end portion 21 and the trunk body portion 22 . Similarly, between the lower portion 30 and the torso body portion 22 there may be a second thickness change region 27 of varying thickness. The lengths in the height direction of the first thickness change region 26 and the second thickness change region 27 may be substantially the same. However, it is not limited to such a mode, and the lengths in the height direction of the first thickness change region 26 and the second thickness change region 27 may be different lengths. When such a first thickness change region 26 exists, the trunk upper end portion 21 is provided within the range of the first distance D1 from the joint portion 40, and the region below the first thickness change region 26 is the trunk body portion. 22.

Each of the upper part 10, the lower part 30 and the body part 20 may be made of metal such as stainless steel (eg SUS304). A base portion 15 may be provided on the upper portion 10 as shown in FIG. 1, and the base portion 15 may be joined to the upper portion 10 by welding. A fitting (not shown) or a down tube (not shown) for pouring out a liquid such as a beverage in the barrel may be attached to the mouthpiece 15 . A peripheral top surface of the upper portion 10 may be provided with a gripping portion 16 for use by the operator to grip the barrel.

The thickness W0 of the upper portion 10 and the thickness W3 of the lower portion 30 may be substantially the same (see FIG. 2). That is, when W0≧W3, W0−W3≦W0×0.05, and conversely, when W0<W3, W3−W0≦W3×0.05.

As an example, the second thickness W2 of the fuselage body portion 22 may be between 0.3 mm and 0.6 mm, and the thickness W3 of the lower portion 30 may be between 0.7 mm and 1.2 mm. A typical value for the second thickness W2 of the fuselage body portion 22 is, for example, 0.5 mm, and a typical value for the thickness W3 of the lower portion 30 is, for example, 0.8 mm. Also, the thickness W0 of the upper portion 10 may be between 0.7 mm and 1.2 mm, and a typical value for the thickness W0 of the upper portion 10 is, for example, 0.8 mm.

The second thickness W2 of the trunk body portion 22 may be 0.3 times or more and 0.9 times or less the thickness W3 of the lower portion 30, and if it is further limited, it is 0.4 times or more and 0.7 times or less. If it is more limited, it may be 0.45 times or more and 0.65 times or less.

The cross section of the body portion 20 may be circular with a diameter of 200 mm to 250 mm. If more limited, the lower limit value of the diameter of the cross section of the body portion 20 may be set to 210 mm, and the upper limit value may be set to 230 mm.

When the barrel contains 10L to 12L of liquid such as beer or soft drink, the height of the bottomed cylindrical part consisting of the lower part 30 and the body part 20 is, for example, 225mm to 275mm. On the other hand, when the barrel holds 18L to 20L of liquid such as beer or soft drink, the height of the bottomed tubular part consisting of the lower part 30 and the body part 20 is, for example, 425mm to 475mm. As an example, the height of a keg capable of accommodating a volume of 10 L consists of 343 mm, and the height of a keg capable of accommodating a volume of 19 L consists of 566 mm.

The crystal structure of the body portion 22 may have a higher dislocation density than the crystal structure of the lower portion 30 . Such an increase in dislocation density causes work hardening.

The fuselage body portion 22 may have a crystal structure that has undergone plastic deformation from the crystal structure of the lower portion 30 . By making the lower part 30 and the body part 20 integral and subjecting them to spin processing, which will be described later, the crystal structure of the body body part 22 has a higher dislocation density than the crystal structure of the lower part 30, and the body body part 22 will have a crystal structure that has undergone plastic deformation from that of lower portion 30 .

≪Manufacturing method≫
Next, an example of the barrel manufacturing method according to the present embodiment will be described.

As for the upper part 10, blanking is first performed to give an appropriate shape (see S11 in FIG. 3). Next, drawing is performed (see S12 in FIG. 3) to produce a first member having a certain degree of depth (first depth). Finally, cut-off processing is performed (see S13 in FIG. 3) to manufacture an upper blank member.

As for the lower portion 30 and the body portion 20, blanking is first performed to give an appropriate shape (see S21 in FIG. 3). Next, drawing is performed (see S22 in FIG. 3) to produce a second member having a certain degree of depth (second depth). This second depth may be substantially the same as the first depth, but the invention is not limited to such a mode, and the second depth may be different from the first depth. Next, spin processing is performed (see S23 in FIG. 3) to increase the length of the portion corresponding to the body upper end portion 21 and reduce the thickness thereof. At this time, spin processing may not be performed on the upper end region of the body upper end portion 21 so that the thickness thereof is not reduced. Finally, cut-off processing is performed (see S24 in FIG. 3) to manufacture the lower fuselage blank member.

Next, the upper blank member and the lower body blank member are joined by welding or the like (see S30 in FIG. 3). As a result, a barrel according to this embodiment is produced.

"effect"
Next, the effects of the present embodiment having the above-described configuration, which have not yet been described, will be mainly described.

When adopting a mode in which the lower part 30 and the body part 20 are integrally configured, and a mode in which the upper part 10 and the body part 20 are joined at the joint part 40, the lower part 30 and the body part 20 are separated. The number of parts can be reduced, and the number of parts to be joined can be reduced, compared to the mode in which it is. Therefore, it is possible to prevent the strength from being weakened and the cost from being increased.

As shown in FIG. 2, by adopting a mode in which the second thickness W2 of the main body portion 22 at a location farther than the first distance D1 from the joint portion 40 is made thinner than the thickness W3 of the lower portion 30, the entire barrel is You can lighten the weight. Further, by adopting a mode in which the first thickness of the body upper end portion 21 within the range of the first distance D1 from the joint portion 40 is substantially the same as the thickness W0 of the upper portion 10, the thickness of the upper portion 10 and the body portion 20 is reduced. Bonding by the bonding portion 40 can be facilitated.

According to experiments conducted by the inventors, in a barrel containing carbonated beverages such as beer and to which a relatively large pressure is applied, the thickness W3 of the lower portion 30 is set to 0.7 mm to 1.2 mm, while the thickness W3 of the body portion 22 is set to 0.7 mm to 1.2 mm. By setting the second thickness W2 to 0.3 mm to 0.6 mm, it was possible to achieve satisfactory pressure resistance. Generally, the lower part 30 having more uneven shapes is inferior to the cylindrical body part 20 in buckling strength (pressure resistance). Considering the volumetric efficiency, the vertical cross-sectional shape of the lower portion 30 is better if it is flat rather than spherical. On the other hand, when adopting such a planar configuration, it does not have to be perfectly hemispherical. Although the hemispherical shape is superior in pressure resistance, the pressure resistance is inferior when the shape is not perfectly hemispherical. Therefore, when the vertical cross-sectional shape of the lower portion 30 adopts an aspect having a planar portion, it is possible to increase the thickness W3 of the lower portion 30 to a range of 0.7 mm to 1.2 mm. particularly beneficial. When pressurized extraction with carbon dioxide gas (high-pressure gas) is employed, it is required to withstand a pressure of, for example, 0.5 MPa, preferably 0.6 MPa, without problems.

On the other hand, the trunk portion 20 is a place that is likely to receive an external impact, and if the second thickness W2 of the trunk body portion 22 is made too thin, there is a possibility that the external impact will cause a dent. From this point of view, it is beneficial to set the lower limit of the second thickness W2 of the trunk body portion 22 to 0.4 mm. When the barrel is reused (if it is a returnable container), if there is a dent, the amount of liquid contained will change from the next time onwards. If the keg contains beer, a change in content can cause weighing problems. For this reason, it is beneficial to set the second thickness W2 of the trunk body portion 22 to a thickness that makes it difficult for a dent to occur.

By setting the second thickness W2 of the body body portion 22 to be 0.3 times or more the thickness W3 of the lower portion 30, it is possible to realize pressure resistance that can withstand even when distributed. In addition to the pressure resistance, the second thickness W2 of the trunk body portion 22 may be 0.4 times or more the thickness W3 of the lower portion 30 in order to prevent unexpected dents from occurring. In order to prevent problems such as unexpected dents from occurring, it may be 0.45 times or more. From the viewpoint of lightening the weight, the second thickness W2 of the trunk body portion 22 may be 0.7 times or less the thickness W3 of the lower portion 30. The thickness W2 may be 0.65 times or less the thickness W3 of the lower portion 30 . If the second thickness W2 of the trunk body portion 22 is 0.45 times or more and 0.65 times or less than the thickness W3 of the lower portion 30, problems such as pressure resistance and unexpected dents are more reliably prevented from occurring. In addition, the weight can be reduced. By reducing the weight of the barrel in this way, a reduction in CO ₂ emitted during transportation (especially a reduction in CO ₂ during collection when the contents are empty) can be expected.

As a result of confirmation by the inventor, the thickness W3 of the upper part 10 and the lower part 30 is 1.0 mm, and the thickness of the body part 20 is 0.65 mm. A container with a volume of 19 liters weighed 3908 g and a container with a capacity of 19 L weighed 4573 g. On the other hand, in the aspect in which the body portion 20 and the lower portion 30 are integrally formed as in the present embodiment, the thickness W3 of the upper portion 10 and the lower portion 30 is 0.8 mm, and the thickness of the body body portion 22 is 0.8 mm. In the embodiment of 0.5 mm, the weight of the container having a capacity of 10 L was 3082 g (however, the weight loss at the rubber portion 60 was 500 g), and the weight of the container having a capacity of 19 L was 3596 g (however, There is 400 g of weight loss at the rubber portion 60.). It has been confirmed that by adopting this aspect in this way, it is possible to considerably reduce the weight while achieving high strength and cost reduction as compared with the three-component aspect.

When adopting a mode in which the thickness W0 of the upper portion 10 and the thickness W3 of the lower portion 30 are substantially the same, the thicknesses of the upper portion 10 and the lower portion 30 should be made thicker than the second thickness W2 of the trunk body portion 22. can be done. The thickness of the lower part 30 is beneficial because the lower part 30 is subjected to a large amount of pressure due to the contained liquid such as beer. As for the upper part 10, it is advantageous to have a large thickness because a large force may be applied when filling the barrel with a liquid such as beer from the mouthpiece part 15.例文帳に追加Further, in the aspect in which the thickness W0 of the upper portion 10 and the thickness W3 of the lower portion 30 are substantially the same, the upper portion 10, the lower portion 30, and the body portion 20 are made of the same plate material such as a metal plate. can be used. For this reason, it is useful in that it can be expected that the purchase cost will be suppressed.

Note that the thickness W0 of the upper portion 10 may be made larger than the thickness W3 of the lower portion 30, considering the strength of the pressure when filling liquid such as beer from the nozzle portion 15. FIG. In other words, the thickness W3 of the lower portion 30 may be reduced to further reduce the weight. In this case, the thickness W3 of the lower portion 30 may be set within the range of 0.8 to 0.9 times the thickness W0 of the upper portion .

When forming the body portion 22 located on the lower side of the body portion 20, spinning processing or the like can be employed. In other words, after performing a drawing process on one sheet material, it is possible to subject the body body portion 22 to a spinning process or the like so as to elongate it. In this case, as described above, the crystal structure of the main body portion 22 has a higher dislocation density than the crystal structure of the lower portion 30, and the crystal structure of the main body portion 22 undergoes plastic deformation from the crystal structure of the lower portion 30. will have Then, by adopting a method of stretching in the axial direction by spinning or the like after drawing, the drawing depth can be made shallow in the drawing, and as a result, the diameter of the body portion 20 (typically diameter of the barrel) can be reduced. Since it is elongated by spin processing or the like, the length of the body portion 20 can be increased, and as a result, the height of the barrel can be increased. For this reason, it is possible to reduce the diameter of a container having a certain volume, such as 10 L to 20 L (typically 10 L or 19 L), and manufacture it. Reducing the diameter in this manner is advantageous in that the installation space in a restaurant or the like can be reduced.

Moreover, when employing spin processing, the hardness of the trunk body portion 22 can be increased. In the conventional mode, it is necessary to select a member with high strength, but in the case of adopting spin processing in this embodiment, even if a material whose original hardness is not so high is selected, it can be processed through spin processing. A change in dislocation density occurs, which can increase its hardness. For this reason, it is possible to widen the selection range of materials, and as a result, it is possible to suppress material costs.

Further, when adopting a mode with a small diameter, there is no need to provide a rib for reinforcement on the body portion 20 (see member 23 in Japanese Patent Application Laid-Open No. 2014-237455).

Considering that a typical beer pallet has a size of 900×1100 (JIS standard), it is beneficial that the diameter of the cross section of the body 20 is 250 mm or less from the viewpoint of efficiently placing barrels. is. In this case, 20 or more can be loaded per pallet.

On the other hand, if the diameter is too small, the keg may overturn (especially when empty during recovery). Therefore, it is beneficial for the cross-sectional diameter of the body portion 20 to be 200 mm or more.

The above description of the embodiment and the disclosure of the drawings are only examples for explaining the invention described in the scope of claims, and the description of the embodiment and the disclosure of the drawings described above constitute the scope of the claims. The claimed invention is not limited.

10 upper part 20 body part 21 body upper end part 22 body body part 30 lower part 40 joint part D1 first distance W0 from the joint part thickness W1 of the upper part first thickness W2 of the upper end of the body second thickness W3 of the body body part downward part thickness

Claims (12)

an upper part;
a lower part;
a body portion provided between the upper portion and the lower portion;
with
The lower portion and the body portion are integrally configured,
A joint is provided between the upper part and the body,
a first thickness of the top portion of the fuselage within a first distance from the joint is substantially the same as the thickness of the top portion;
A second thickness of the trunk body portion at a location farther than the first distance from the joint portion is thinner than the thickness of the lower portion ,
A barrel in which the thickness of the lower part is 0.8 to 0.9 times the thickness of the upper part . an upper part;
a lower part;
a body portion provided between the upper portion and the lower portion;
with
The lower portion and the body portion are integrally configured,
A joint is provided between the upper part and the body,
a first thickness of the top portion of the fuselage within a first distance from the joint is substantially the same as the thickness of the top portion;
A second thickness of the trunk body portion at a location farther than the first distance from the joint portion is thinner than the thickness of the lower portion,
The crystalline structure of the barrel body portion has a higher dislocation density than the crystalline structure of the lower portion. an upper part;
a lower part;
a body portion provided between the upper portion and the lower portion;
with
The lower portion and the body portion are integrally configured,
A joint is provided between the upper part and the body,
a first thickness of the upper portion of the fuselage within a first distance from the joint is substantially the same as the thickness of the upper portion;
A second thickness of the trunk body portion at a location farther than the first distance from the joint portion is thinner than the thickness of the lower portion,
The second thickness of the body main body is 0.4 mm to 0.6 mm,
A barrel in which the thickness of the lower part is 0.7 mm to 1.2 mm. an upper part;
a lower part;
a body portion provided between the upper portion and the lower portion;
with
The lower portion and the body portion are integrally configured,
A joint is provided between the upper part and the body,
a first thickness of the top portion of the fuselage within a first distance from the joint is substantially the same as the thickness of the top portion;
A second thickness of the trunk body portion at a location farther than the first distance from the joint portion is thinner than the thickness of the lower portion,
The second thickness of the barrel main body is 0.3 times or more and 0.9 times or less of the thickness of the lower portion. an upper part;
a lower part;
a body portion provided between the upper portion and the lower portion;
with
The lower portion and the body portion are integrally configured,
A joint is provided between the upper part and the body,
a first thickness of the top portion of the fuselage within a first distance from the joint is substantially the same as the thickness of the top portion;
A second thickness of the trunk body portion at a location farther than the first distance from the joint portion is thinner than the thickness of the lower portion,
The barrel has a circular cross section with a diameter of 200 mm to 250 mm. 6. A barrel according to any one of claims 1 to 5, wherein the thickness of the upper part and the thickness of the lower part are substantially the same. 7. A barrel according to any one of claims 1 to 6 , wherein the body portion has a crystal structure that has undergone plastic deformation from the crystal structure of the lower portion. a first drawing step of drawing to produce a first member having a first depth;
a second drawing step of drawing to produce a second member having a second depth;
A spin processing step of performing spin processing on a portion corresponding to the side surface of the second member to reduce the thickness of a part of the side surface of the second member;
A joining step of joining the first member and the second member that has undergone the spin processing step;
with
The end of the second member on the first member side is not subjected to spin processing, and the thickness of the second member within the range of the first distance from the joint between the first member and the second member is substantially the same as the thickness of the first member,
The first member serves as an upper portion,
The second member comprises: a fuselage upper end portion within a first distance from a junction of the first member and the second member; and a fuselage body portion at a location farther than the first distance from the junction; a lower portion provided on the opposite side of the fuselage upper end portion of the fuselage body portion;
A method for manufacturing a barrel in which the thickness of the lower portion is 0.8 to 0.9 times the thickness of the upper portion . a first drawing step of drawing to produce a first member having a first depth;
a second drawing step of drawing to produce a second member having a second depth;
A spin processing step of performing spin processing on a portion corresponding to the side surface of the second member to reduce the thickness of a part of the side surface of the second member;
A joining step of joining the first member and the second member that has undergone the spin processing step;
with
The end of the second member on the first member side is not subjected to spin processing, and the thickness of the second member within the range of the first distance from the joint between the first member and the second member is substantially the same as the thickness of the first member,
The first member serves as an upper portion,
The second member comprises: a fuselage upper end portion within a first distance from a junction of the first member and the second member; and a fuselage body portion at a location farther than the first distance from the junction; a lower portion provided on the opposite side of the fuselage upper end portion of the fuselage body portion;
A method of manufacturing a barrel according to claim 1, wherein the crystalline structure of the barrel body portion has a higher dislocation density than the crystalline structure of the lower portion. a first drawing step of drawing to produce a first member having a first depth;
a second drawing step of drawing to produce a second member having a second depth;
A spin processing step of performing spin processing on a portion corresponding to the side surface of the second member to reduce the thickness of a part of the side surface of the second member;
A joining step of joining the first member and the second member that has undergone the spin processing step;
with
The end of the second member on the first member side is not subjected to spin processing, and the thickness of the second member within the range of the first distance from the joint between the first member and the second member is substantially the same as the thickness of the first member,
The first member is the upper part,
The second member comprises: a fuselage upper end portion within a first distance from a junction of the first member and the second member; and a fuselage body portion at a location farther than the first distance from the junction; a lower portion provided on the opposite side of the fuselage upper end portion of the fuselage body portion;
The second thickness of the trunk main body is 0.4 mm to 0.6 mm,
A method for manufacturing a barrel in which the thickness of the lower portion is 0.7 mm to 1.2 mm. a first drawing step of drawing to produce a first member having a first depth;
a second drawing step of drawing to produce a second member having a second depth;
A spin processing step of performing spin processing on a portion corresponding to the side surface of the second member to reduce the thickness of a part of the side surface of the second member;
A joining step of joining the first member and the second member that has undergone the spin processing step;
with
The end of the second member on the first member side is not subjected to spin processing, and the thickness of the second member within the range of the first distance from the joint between the first member and the second member is substantially the same as the thickness of the first member,
The first member serves as an upper portion,
The second member comprises: a fuselage upper end portion within a first distance from a junction of the first member and the second member; and a fuselage body portion at a location farther than the first distance from the junction; a lower portion provided on the opposite side of the fuselage upper end portion of the fuselage body portion;
A method for manufacturing a barrel, wherein the second thickness of the barrel main body is 0.3 to 0.9 times the thickness of the lower portion. a first drawing step of drawing to produce a first member having a first depth;
a second drawing step of drawing to produce a second member having a second depth;
A spin processing step of performing spin processing on a portion corresponding to the side surface of the second member to reduce the thickness of a part of the side surface of the second member;
A joining step of joining the first member and the second member that has undergone the spin processing step;
with
The end of the second member on the first member side is not subjected to spin processing, and the thickness of the second member within the range of the first distance from the joint between the first member and the second member is substantially the same as the thickness of the first member,
The first member serves as an upper portion,
The second member has a fuselage upper end within a first distance from the junction of the first member and the second member, and a fuselage body portion at a location greater than the first distance from the junction. and a lower portion provided on the opposite side of the fuselage upper end of the fuselage main body,
A method for manufacturing a barrel in which the cross section of the barrel is circular with a diameter of 200 mm to 250 mm.

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