JP3844633B2 - Pipe body, pipe body sheet metal, and pipe body molding method using pipe body sheet metal - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pipe body and a pipe body sheet metal having a closed cross-section formed by forming seams between edges having mutually intersecting surfaces, and a pipe body molding method using the pipe body sheet metal.
[0002]
[Prior art]
Conventionally, a technique described in Japanese Patent Application Laid-Open No. 11-290940 has been known as a technique for manufacturing a pipe body, for example, a prismatic pipe body by bending a metal plate.
[0003]
The one disclosed in this publication uses a rectangular metal plate as a raw material, and a prismatic pipe body is formed by press working in a plurality of steps.
[0004]
That is, this prismatic pipe body processing method includes a bottom plate that connects both ends of the metal plate facing each other and the flange portions facing each other by bending both ends in the width direction of the metal plate at right angles in the same direction along the length direction. And forming a concave curved surface having a predetermined width along the length direction on the bottom plate portion of the primary molded product, and both ends of the concave curved surface on the inside. A second bending step of forming a secondary molded product having a pair of side walls opposed to each other by bending substantially at a right angle and having a substantially U-shaped cross section; and the pair of side walls of the secondary molded product inside each other It comprises a wrist-like process in which the end faces of the pair of flange portions are pressed against each other and pressed.
[0005]
Then, according to this method of processing a prismatic pipe body, when forming a secondary molded product, the concave curved surface formed on the bottom plate portion of the secondary molded product presses the pair of side wall portions toward each other inward. In order to fulfill the function of suppressing the springback force generated by the above, a prismatic pipe body having a square cross section in which the end surfaces of the flange portions are in close contact with each other without welding the end surfaces of the flange portions is manufactured only by press molding.
[0006]
[Problems to be solved by the invention]
However, in this conventional method of processing a prismatic pipe body, when forming a secondary molded product, the concave curved surface formed on the bottom plate portion of the secondary molded product presses the pair of side wall portions toward each other inward. Although it functions to suppress the springback force generated by the prism, the springback force that tries to open outwards remains on the pair of side walls, and the prisms in which the end faces of the flanges are in close contact during mass production It was difficult to produce a pipe body stably without variation.
[0007]
That is, when examining whether or not the end faces of the flange portions of the prismatic pipe body manufactured by this processing method are in close contact with each other, there are some that the end faces are almost in close contact with each other. As a result, there are quite a few gaps between the end faces, and the gaps also vary.
[0008]
The present invention has been made in view of the above circumstances, and the object of the present invention is a pipe body in which the seam is stably adhered while being molded only by press molding without welding during mass production. Another object of the present invention is to provide a pipe body sheet metal and a pipe body molding method using the pipe body sheet metal.
[0009]
[Means for Solving the Problems]
In order to achieve the object, the invention according to claim 1 is configured such that the end face of one edge portion of the surface intersecting each other and the back surface of the other edge portion are formed by bending the sheet metal. In the pipe body that forms a closed section by
A male side engaging portion protruding from the end surface is formed on an end surface of the one edge portion, and a female side engaging portion in which the male side engaging portion is engaged with the other edge portion. The female side engaging portion is a recess that penetrates the other edge in the sheet thickness direction of the sheet metal and opens to the end surface of the other edge, and in the width direction of the recess. are formed respectively fitting recess on both side surfaces facing each other, the male-side engaging portion is fastened by and the respective edge portions missing to the female-side engaging portion are in close contact by deformation of its In this state, it is fitted to the female side engaging portion, and a part of the male side engaging portion is inserted into each fitting recess due to deformation of the male side engaging portion .
[0010]
According to such a configuration of claim 1, the spring back at the time of press molding is absorbed by the fitting that is prevented from coming off due to the deformation of the male side engaging portion, and the pipe body in which the edges are in close contact with each other It has become.
[0011]
According to a second aspect of the present invention, a deformable male engagement portion projects from an end face of one edge of a rectangular sheet metal, and the male engagement portion is formed at an edge parallel to the one edge. A female engagement portion that can be engaged with the pipe, by engaging the male engagement portion with the female engagement portion in a state in which the two edge portions face each other so as to cross each other. A pipe body sheet metal for forming a body, wherein the female side engaging portion is a recess that penetrates the other edge and opens to an end surface of the other edge, and in the width direction of the recess. Fitting recesses are formed on both side surfaces facing each other, the male side engaging portion is fitted into the female side engaging portion by deformation thereof, and a part of the male side engaging portion is A pipe body sheet metal whose gist is to enter each of the fitting recesses during deformation .
[0012]
According to such a configuration of claim 2, it is possible to provide a pipe body sheet metal for providing a pipe body in which a pair of edges are in close contact with each other by a predetermined pressing process. Can also be done easily.
[0013]
The gist of the invention described in claim 3 is that the protruding amount of the male engagement portion from the end face is larger than the thickness of the rectangular sheet metal.
[0014]
According to the structure of Claim 3, since the protrusion amount from the end surface of a male side engaging part is larger than the thickness of a sheet metal, a deformation | transformation of the male side engaging part by a press machine can be performed easily. .
[0015]
The gist of the invention described in claim 4 is that the protruding amount of the male engagement portion from the end face is substantially the same as the thickness of the rectangular sheet metal.
[0016]
According to the configuration of the fourth aspect, since the protruding amount from the end face of the male side engaging portion is substantially the same as the thickness of the sheet metal, the male side engaging portion is deformed after the male side engaging portion is deformed by the press machine. The tip of the part hardly protrudes from the surface, and the flatness of the surface can be easily secured.
[0017]
The invention according to claim 5, wherein the female-side engaging portion is summarized in that said being wider set than the width of the male-side engaging portion.
[0018]
According to the fifth aspect of the present invention, the male side engaging portion can be easily engaged with the female side engaging portion.
[0019]
The gist of the invention described in claim 6 is that the recess has an opening diameter near the open end narrower than an opening diameter near the bottom edge.
[0020]
According to the structure of Claim 6, fitting with the female side engaging part at the time of deforming the male side engaging part can be performed easily and reliably.
[0021]
According to a seventh aspect of the present invention, the pipe body sheet metal according to any one of the second to sixth aspects is bent along a pair of parallel edges to form a plurality of surfaces and the plurality of surfaces. The surfaces having the pair of parallel edges intersect each other and the pair of parallel edges are opposed to each other in a separated state, and the male engagement portion protruding from one end surface of the parallel edges is the other. After engaging the female side engaging portion formed at the edge of the mating portion to form a seam, the male side engaging portion is deformed and fitted into the female side engaging portion, and the male side engaging portion the variation allowed to enter a part of the male-side engaging portion on each of the fitting in the recess and gist of Rukoto.
[0022]
According to an eighth aspect of the present invention, the pipe body sheet metal according to any one of the second to sixth aspects is bent along a pair of parallel edges to form a plurality of surfaces and the plurality of surfaces. A first step of obtaining a first workpiece by crossing the surfaces having the pair of parallel edges and opposing the pair of parallel edges in a separated state; and one end face of the parallel edges a second step of obtaining a projecting the second workpiece to form seams engages the female-side engaging portion formed on the other edge of the male side engaging portion from the male-side engaging portion A third step of obtaining a pipe body by deforming and fitting into the female side engaging portion, and by deforming the male side engaging portion, causing a part of the male side engaging portion to enter the respective fitting recesses It is summarized as having.
[0023]
According to such a description of claim 7 and claim 8, it is possible to form a pipe body in which the joints are in close contact with each other only by a simple pressing process, and press fitting is achieved by deformation of the female side engaging portion. Can be done in the process.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0025]
(Embodiment 1)
In FIG. 1 (A), 1 is the pipe body of this invention. The pipe body 1 is formed in a quadrangular prism having four surfaces 11, 12, 13, and 14. The surface 11 that intersects each other (in this case, orthogonal) and the edges 11 a and 14 a of the surface 14 are combined. The seam 15 is configured by the end surface 14b of the edge portion 14a contacting the back surface 11b of the edge portion 11a.
[0026]
Further, as shown in FIGS. 1B and 1C, which are enlarged views of the main parts before the formation of the pipe body 1, the edges 11a and 14a are opposed to each other in a direction intersecting (orthogonal) with each other. A concave portion 11c (female side engaging portion) and a convex portion 14c (male side engaging portion) are formed. As shown in FIGS. 1 (D) and 1 (E), which are enlarged views of the main portion of the pipe body 1 in a state where the pipe body 1 is completely formed, the convex portion 14c is fitted into the concave portion 11c. And the end face 14b of the surface 14 can be a seam 15 in close contact.
[0027]
2A and 2B show a sheet metal 1A for forming such a pipe body 1. FIG. This sheet metal 1A is formed by punching from a metal sheet material as a raw material.
[0028]
The recess 11 c is open to the end surface 11 d of the surface 11. Further, as shown in FIG. 2 (A), the inner width W1 on the bottom wall 11e side of the recess 11c is set wider than the opening width W2 on the end surface 11d side. A fitting recess 11g having an inclined surface 11f that approaches (becomes narrower) toward the side is formed.
[0029]
In the convex portion 14c, the width W3 along the longitudinal direction of the end face 14b is smaller than the opening width W2. Moreover, the longitudinal direction both ends of the convex part 14c protrude from the center part. Further, as shown in FIG. 2B, the maximum protrusion amount H1 of the convex portion 14c is larger than the thickness H2 of the sheet metal 1A, and the depth H3 of the concave portion 11c is the same as the thickness H2 of the sheet metal 1A.
[0030]
As a result, as shown in FIG. 1B, both end portions of the convex portion 14c protrude from the surface 11h of the surface 11 in a state where the concave portion 11c and the convex portion 14c are engaged. In FIG. 2, the same reference numerals are given to the constituent parts of the molded pipe body 1 and the description thereof is omitted. Further, reference numerals P1, P2 and P3 in FIG. 2 are explanatory lines showing the bending positions by the press machine. The bending positions indicated by the explanatory lines P1, P2, and P3 are designed in consideration of the amount of extension of the sheet metal 1A during press molding. Further, the sheet metal 1A is formed with a plurality of holes 11i for fixing to a machine (die) at the time of press working, which will be described later, on the surface 13 or the other surfaces 11, 12, and 14 including the main body of the copying machine. The application range is processed according to the purpose of use of the pipe body 1 such as the formation of screw holes 11j for panel fixing or component fixing. At this time, the screw hole 11j may be a so-called fool hole, or the hole 11i may be used as a screw hole and also used as a mold fixing hole. Further, the positions and the number of the holes 11i and 11j are not limited and may be formed after the pipe body is formed.
[0031]
The case where the square columnar pipe body 1 is formed using such a sheet metal 1A will be described with reference to FIG.
[0032]
First, the explanatory lines P1 to P3 of the sheet metal 1A are bent by a known press machine (in the case of a quadrangular prism, the angles formed by the surfaces 11 and 12 and the surfaces 12 and 13 are 90 °, the surfaces 13 and 14 are As shown in FIG. 3A, the primary processed product 1B is formed.
[0033]
Next, the primary processed product 1 </ b> B is set on the lower mold 21 of the press machine 20. At this time, the surface 13 of the primary processed product 1 </ b> B is fixed to the lower die 21 by the presser mechanism 22 provided on the lower die 21.
[0034]
From this state, as shown in FIG. 3 (B), the upper die 23 is lowered and the upper die 23 brings the press portions 24 of the lower die 21 closer to each other while bringing the edges 11a and 14a closer to each other, thereby forming the recess 11c. And the convex portion 14c are engaged with each other to obtain a secondary processed product 1C.
[0035]
Further, as shown in FIG. 3C, the upper die 23 is further lowered from this state, so that the press portion 25 of the upper die 23 is fixed by the press portion 24 while the approach position of the press portion 24 of the lower die 21 is fixed. Both ends of the convex portion 14c are deformed while pressurizing the secondary processed product 1C from a direction orthogonal to the pressing direction. In this deformation, since the crushed part of the convex part 14c enters the fitting concave part 11g of the concave part 11c, as a result, the concave part 11c and the convex part 14c are fitted as shown in FIG.
[0036]
Under the present circumstances, since pressurization by the press part 25 is a direction orthogonal to the press direction by the press part 24, the shaping effect of the surfaces 11-14 can be acquired. Moreover, the pipe body 1 in a state in which the back surface 11b of the surface 11 and the end surface 14b of the surface 14 are in close contact with each other can be obtained by fitting the concave portion 11c and the convex portion 14c.
[0037]
By the way, the secondary processed product 1C is not a substantially processed product because it is in the middle of a pressing process in which the primary processed product 1B is processed into the pipe body 1. In addition, in order to obtain the above-described effect, the pressing by the pressing unit 24 is of course not caused to cause deformation (collapse) of the pipe body 1, and the degree thereof is determined by the thickness H 2 of the sheet metal 1 A and the like. It is set according to conditions such as material.
[0038]
(Embodiment 2)
In FIG. 4 (A), 3 is the pipe body of this invention. The pipe body 3 is formed in a quadrangular prism having four surfaces 31, 32, 33, and 34, and the surface 31 that intersects (in this case, orthogonal) and the edges 31 a and 34 a of the surface 34 are combined. The seam 35 is configured by the end surface 34b of the edge 34a abutting against the back surface 31b of the edge 31a.
[0039]
Moreover, as shown to FIG. 4 (B) and (C) which are the principal part enlarged views before the completion of formation of the pipe body 3, it opposes the edge parts 31a and 34a in the direction which mutually crossed (orthogonal). A concave portion 31c (female side engaging portion) and a convex portion 34c (male side engaging portion) are formed. As shown in FIGS. 4D and 4E, which are enlarged views of the main portion of the pipe body 3 in a state where the pipe body 3 is completely formed, the convex portion 34c is fitted into the concave portion 31c by the deformation, and thereby the back surface 31b of the surface 31 is formed. And an end face 34b of the surface 34 can be formed as a joint 35.
[0040]
5A and 5B show a sheet metal 3A for forming such a pipe body 3. FIG. The sheet metal 3A is formed by punching from a metal sheet material as a raw material.
[0041]
The recess 31 c is open to the end surface 31 d of the surface 31. Further, as shown in FIG. 5A, the inner width W4 on the bottom wall 31e side of the recess 31c is set wider than the opening width W5 on the end surface 31d side. A fitting recess 31g having an inclined surface 31f that approaches (becomes narrower) toward the side is formed.
[0042]
The protrusion 34c has a width W6 along the longitudinal direction of the end face 34b that is smaller than the opening width W5. Further, as shown in FIG. 5B, the maximum protrusion amount H4 of the protrusion 34c is substantially the same as the thickness H5 of the sheet metal 3A, and the depth H6 of the recess 31c is substantially the same as the thickness H5 of the sheet metal 3A. .
[0043]
As a result, as shown in FIG. 4B, the surface 31h of the surface 31 and the convex portion 34c are substantially flush with each other when the concave portion 31c and the convex portion 34c are engaged. In this FIG. 5, the same code | symbol is attached | subjected to the component of the pipe body 3 after shaping | molding, and the description is abbreviate | omitted. In addition, reference signs P1, P2, and P3 in FIG. 5 are explanatory lines that indicate bending positions by a press machine. The bending positions indicated by the explanatory lines P1, P2, and P3 are designed in consideration of the amount of extension of the sheet metal 1A during press molding. Further, the sheet metal 3A is provided with a plurality of holes 31i for fixing to a machine (die) at the time of press processing, which will be described later, on the surface 33, or the main body of the copying machine including the other surfaces 31, 32, 34. The application range is processed according to the purpose of use of the pipe body 3, such as a screw hole 31j for panel fixing or component fixing. At this time, the screw hole 31j may be a so-called fool hole, or the hole 31i may be used as a screw hole and also as a mold fixing hole. Further, the positions and the number of the holes 31i and 31j are not limited. Of course, the holes 31i and 31j may be formed after the pipe body is formed.
[0044]
The case where the square columnar pipe body 3 is formed using such a sheet metal 3A will be described with reference to FIG.
[0045]
First, the explanatory lines P1 to P3 of the sheet metal 3A are bent by a known press machine (in the case of a quadrangular prism, the angles formed by the surfaces 31 and 32 and the surfaces 32 and 33 are 90 °, and the surfaces 33 and 34 are As shown in FIG. 6A, the primary processed product 3B is formed.
[0046]
Next, the primary processed product 3 </ b> B is set on the lower mold 41 of the press machine 40. At this time, the surface 33 of the primary processed product 3 </ b> B is fixed to the lower die 41 by the presser mechanism 42 provided on the lower die 41.
[0047]
From this state, as shown in FIG. 6 (B), the upper die 43 is lowered and the upper die 43 brings the press portions 44 of the lower die 41 closer to each other while bringing the edges 31a and 34a closer to each other, thereby forming the recess 31c. And the convex portion 34c are engaged with each other to obtain a secondary processed product 3C.
[0048]
Further, as shown in FIG. 6C, the upper die 43 is further lowered from this state, so that the pressing portion 45 of the upper die 43 is fixed by the pressing portion 44 while the approach position of the pressing portion 44 of the lower die 41 is fixed. The secondary processed product 3C is pressurized from the direction orthogonal to the pressing direction.
[0049]
At this time, as shown in FIG. 7, the punch portion 46 projects from the press portion 45 at a position facing the convex portion 34 c, and the convex portion 34 c is deformed by the punch portion 46. Since a part of the convex portion 34c enters the fitting concave portion 31g of the concave portion 31c, as a result, the concave portion 31c and the convex portion 34c are fitted as shown in FIG.
[0050]
Under the present circumstances, since pressurization by press part 45 is a direction orthogonal to a press direction by press part 44, the shaping effect of surfaces 31-34 can be acquired. Moreover, the pipe body 3 in a state in which the rear surface 31b of the surface 31 and the end surface 34b of the surface 34 are in close contact with each other can be obtained by fitting the concave portion 31c and the convex portion 34c.
[0051]
By the way, the secondary processed product 3C is not a substantially processed product because it is in the middle of a pressing process in which the primary processed product 3B is processed into the pipe body 3. In addition, in order to obtain the above-described effect, the pressing by the press unit 44 is of course not caused to cause deformation (collapse) of the pipe body 3, and the degree thereof is determined by the thickness H 5 of the sheet metal 3 A and the like. It is set according to conditions such as material.
[0052]
【The invention's effect】
As described above, according to the configuration of the first aspect, the springback at the time of press molding is absorbed and the edges are brought into close contact with each other by the fitting that is prevented from coming off due to the deformation of the male side engaging portion. Therefore, the seam can be stably adhered while being molded only by press molding without welding during mass production.
[0053]
According to the structure of Claim 2, it can be set as the pipe body sheet metal for providing the pipe body which a pair of edge part closely_contact | adhered by the predetermined press process, and also the conveyance at the time of distribution, etc. are easy. It can be carried out.
[0054]
According to the structure of Claim 3, since the protrusion amount from the end surface of a male side engaging part is larger than the thickness of a sheet metal, a deformation | transformation of the male side engaging part by a press machine can be performed easily. .
[0055]
According to the configuration of the fourth aspect, since the protruding amount from the end face of the male side engaging portion is substantially the same as the thickness of the sheet metal, the male side engaging portion is deformed after the male side engaging portion is deformed by the press machine. The tip of the part hardly protrudes from the surface, and the flatness of the surface can be easily secured.
[0056]
According to the fifth aspect of the present invention, the male side engaging portion can be easily engaged with the female side engaging portion.
[0057]
According to the sixth aspect, the fitting with the female side engaging portion when the male side engaging portion is deformed can be easily and reliably performed.
[0058]
According to the seventh and eighth aspects of the present invention, it is possible to form a pipe body in which the seams are in close contact with each other only by a simple pressing process, and the fitting by the deformation of the female side engaging portion is performed in the pressing process. be able to.
[Brief description of the drawings]
FIGS. 1A and 1B show a pipe body according to Embodiment 1 of the present invention, in which FIG. 1A is an external perspective view of the pipe body, FIG. 1B is an enlarged view of a main part before the formation of the pipe body, and FIG. It is an enlarged view of the principal part of the formation completion state of a body.
FIG. 2 is a plan view of a sheet metal according to the first embodiment of the present invention.
FIGS. 3A and 3B are time-series explanatory views according to the first embodiment of the present invention, in which FIG. 3A is a sectional view of a press machine with a primary processed product set, and FIG. 3B is a secondary processed product molded state; Sectional drawing of a press machine, (C) is sectional drawing of the press machine of a pipe body shaping | molding completion state.
FIGS. 4A and 4B show a pipe body according to Embodiment 2 of the present invention, in which FIG. 4A is an external perspective view of the pipe body, FIG. 4B is an enlarged view of a main part before the formation of the pipe body, and FIG. It is an enlarged view of the principal part of the formation completion state of a body.
FIG. 5 is a plan view of a sheet metal according to Embodiment 2 of the present invention.
6A and 6B are time-series explanatory views according to Embodiment 2 of the present invention, in which FIG. 6A is a cross-sectional view of a press machine with a primary processed product set, and FIG. 6B is a secondary processed product molded state; Sectional drawing of a press machine, (C) is sectional drawing of the press machine of a pipe body shaping | molding completion state.
FIG. 7 is a partially enlarged view of a mold used when forming a pipe body according to Embodiment 2 of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Pipe body 11 ... Surface 11a ... Edge part 11b ... Back surface 11c ... Recessed part (female side engaging part)
11d ... End surface 11e ... Bottom wall 11f ... Inclined surface 11g ... Fitting recess 12 ... Surface 13 ... Surface 14 ... Surface 14a ... Edge portion 14b ... End surface 14c ... Convex portion (male side engaging portion)
15 ... Joint 1A ... Sheet metal 1B ... Primary processed product 1C ... Secondary processed product

Claims (8)

In the pipe body in which a closed cross section is formed by forming a seam between the end surface of one edge portion of the surfaces intersecting each other and the back surface of the other edge portion by bending the sheet metal ,
A male side engaging portion protruding from the end surface is formed on an end surface of the one edge portion, and a female side engaging portion in which the male side engaging portion is engaged with the other edge portion. The female side engaging portion is a recess that penetrates the other edge in the sheet thickness direction of the sheet metal and opens to the end surface of the other edge, and in the width direction of the recess. are formed respectively fitting recess on both side surfaces facing each other, the male-side engaging portion is fastened by and the respective edge portions missing to the female-side engaging portion are in close contact by deformation of its The pipe body is fitted in the female engagement portion in a state, and a part of the male engagement portion is inserted into each of the fitting recesses by deformation of the male engagement portion. . A deformable male engagement portion projects from an end face of one edge of a rectangular sheet metal, and a female engagement that can engage with the male engagement portion at an edge parallel to the one edge. And a pipe body for forming a pipe body by engaging the male side engaging part with the female side engaging part in a state where the both edge parts face each other so as to cross each other. The female-side engaging portion is a concave portion that penetrates the other edge and opens to an end surface of the other edge, and is fitted to both side surfaces facing each other in the width direction of the concave portion. A mating recess is formed, and the male engagement portion is fitted into the female engagement portion by deformation thereof, and a part of the male engagement portion is in each fitting recess at the time of deformation. Sheet metal for pipe bodies, characterized by entering .   The sheet metal for a pipe body according to claim 2, wherein an amount of protrusion of the push-side engaging portion from the end surface is larger than a thickness of the rectangular sheet metal.   The sheet metal for a pipe body according to claim 2, wherein an amount of protrusion of the push-side engaging portion from the end surface is substantially the same as a thickness of the rectangular sheet metal. The female-side engaging portion, the pipe for sheet metal according to any one of claims 2 to 4, characterized in that it is set wider than the width of the male-side engaging portion.   The pipe body sheet metal according to claim 5, wherein the recess has an opening diameter near the open end narrower than an opening diameter near the bottom edge. The pipe body sheet metal according to any one of claims 2 to 6 is bent along a pair of parallel edges to form a plurality of faces, and the pair of parallel edges among the plurality of faces. And a pair of parallel edges facing each other in a separated state, and a male side engaging part protruding from one end face of the parallel edges is formed on the other edge. After engaging the engaging portion to form a seam, the male engaging portion is deformed and fitted to the female engaging portion, and the male engaging portion is deformed by deformation of the male engaging portion. method of forming a pipe body part, characterized in Rukoto intruded into the respective fitting the recess of the. The pipe body sheet metal according to any one of claims 2 to 6 is bent along a pair of parallel edges to form a plurality of faces, and the pair of parallel edges among the plurality of faces. A first step of obtaining a first processed product by crossing surfaces having a crossing and facing the pair of parallel edges in a separated state; and a male engagement portion protruding from one end face of the parallel edges a second step of obtaining the other of the second workpiece formed with seams engages the female-side engaging portion formed on the edge of the female-side engaging by deforming the male-side engaging portion And a third step of obtaining a pipe body by fitting a part of the male side engaging part into the respective fitting recesses by deformation of the male side engaging part. Body molding method.

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