Pipe processing apparatus and pipe processing method

Abstract

To provide a pipe working device working the ends of pipes for easily linearly connecting the pipes while suppressing cost.SOLUTION: A pipe working device includes a molding die 1 for relatively press-fitting the ends of cylindrical pipes. The molding die 1 comprises: a die main body 10 having a bottomed cylindrical shape which has a single-diameter cylindrical portion 11 with the constant inner diameter and a guide portion 12 having inner diameter gradually expanding toward an open end E of the bottomed cylindrical shape from the single-diameter cylindrical portion 11; and a cylindrical member 20 which extends in the same axial direction as the die main body 10 from a bottom 15 of the die main body 10 to the open end E side. The cylindrical member 20 includes: a large-diameter portion 22 which is positioned outward from the open end E of the die main body 10 and has an outer diameter smaller than the inner diameter of the single-diameter cylindrical portion 11; and a small-diameter shaft portion 21 which has an outer diameter smaller than the large-diameter portion 22 and supports the large-diameter portion 22 with respect to the bottom 15 of the die main body 10.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a pipe processing apparatus for processing pipe ends, and a pipe processing method using the pipe processing apparatus.

Background Art

[0002] As means for linearly connecting pipes, conventionally, means such as connecting the ends of pipes by welding, forming flanges at the ends of pipes, and connecting the overlapping flanges with bolts have been adopted. Further, when the pipe is a cylindrical pipe, a thread is formed at the end of the pipe and connected with a joint member having a thread groove, the pipes are respectively inserted into both ends of a cylindrical joint member having an inner diameter substantially equal to the outer diameter of the pipe for connection, and the pipes are respectively externally fitted and connected from both ends of a joint member whose outer diameter at the central portion is equal to or greater than the inner diameter of the pipe and whose outer diameter gradually decreases toward both ends.

[0003] However, all of these have problems such as being time-consuming for connection. Further, when using a joint member, there is a problem that the number of parts increases and the cost increases.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Therefore, in view of the above circumstances, an object of the present invention is to provide a pipe processing apparatus for processing the ends of pipes, and a pipe processing method using the pipe processing apparatus, in order to easily connect pipes linearly while suppressing costs.

Means for Solving the Problems

[0005] In order to solve the above problems, a pipe processing apparatus according to the present invention is a pipe processing apparatus including a mold for relatively press-fitting the ends of a cylindrical pipe, the mold is A bottomed cylindrical mold body having a single-diameter cylindrical portion with a constant inner diameter and a guide portion whose inner diameter gradually expands from the single-diameter cylindrical portion, A cylindrical member extending in the same axial direction as the mold body from the bottom of the mold body toward the open end side, The cylindrical member Has a large-diameter portion located outside the open end of the mold body and having an outer diameter smaller than the inner diameter of the single-diameter cylindrical portion, And a small-diameter shaft portion having an outer diameter smaller than that of the large-diameter portion and supporting the large-diameter portion with respect to the bottom of the mold body.

[0006] The pipe processing device of this configuration is a device for forming a reduced-diameter processing portion at the end of a cylindrical pipe. By using the pipe processing device of this configuration, a reduced-diameter processing portion can be formed at the end of a cylindrical pipe by the following pipe processing method. That is, "By relatively press-fitting the end of a cylindrical pipe whose outer diameter is larger than the minimum diameter and smaller than or equal to the maximum diameter of the guide portion into the inside of the forming die in a state where it is in contact with the guide portion, after pressing the end of the cylindrical pipe from the outer peripheral surface side, By relatively pulling out the end of the cylindrical pipe from the forming die, by pressing the end of the cylindrical pipe from the inner peripheral surface side by the large-diameter portion, A reduced-diameter processing portion is formed at the end of the cylindrical pipe, the outer diameter of which is substantially equal to the inner diameter of the single-diameter cylindrical portion and the inner diameter of which is substantially equal to the outer diameter of the large-diameter portion." This is the pipe processing method.

[0007] As will be described in detail later, simply press-fitting the end of a cylindrical pipe into the inside of a forming die having an inner diameter smaller than the outer diameter of the cylindrical pipe cannot form a reduced-diameter processing portion with a uniform outer diameter and inner diameter, and non-uniform deformation will occur. On the other hand, the forming die of the pipe processing device of the present invention includes a cylindrical member having a large-diameter portion inside a bottomed cylindrical mold body. When the end of the cylindrical pipe press-fitted into the inside of the forming die is relatively pulled out from the formed body, by pressing the pipe end from the inner peripheral surface side by the large-diameter portion, non-uniform deformation of the pipe end can be corrected, and a reduced-diameter processing portion with a uniform outer diameter and inner diameter can be formed.

[0008] Since the cylindrical pipe having the reduced-diameter processing portion at the end can be connected simply by inserting the reduced-diameter processing portion into the unprocessed portion of the cylindrical pipe having the same diameter, the connection work is easy. Further, since no joint member for connection is required, the cost can be reduced.

[0009] In addition to the above configuration, the pipe processing apparatus according to the present invention "The cylindrical member has an outer diameter substantially equal to the inner diameter of the single-diameter cylindrical portion at the end opposite to the large-diameter portion of and has a base portion, and is detachable from the mold body and includes a plurality of the columnar members having different axial lengths of the base portions " can be adopted. Alternatively, "the columnar member has a base portion having an outer diameter substantially equal to the inner diameter of the single-diameter cylindrical portion at an end opposite to the large-diameter portion, is detachable from the mold body, and the base portion is detachable from the small-diameter shaft portion".

[0010] In this configuration, since the cylindrical member is detachable from the mold body, it can be replaced when it is damaged such as worn out. Further, in this configuration, the cylindrical member has a base portion. When the end portion of the cylindrical pipe is press-fitted into the molding die, the inner end surface inside the molding die is strongly pressed by the tip of the pipe and is likely to be damaged. On the other hand, in this configuration in which the cylindrical member has a base portion with an outer diameter substantially equal to the inner diameter of the single-diameter cylindrical portion, the surface on the open end side of the base portion constitutes the inner end surface. Therefore, by replacing the cylindrical member, the inner end surface that is likely to be damaged can be easily replaced.

[0011] In addition, since the cylindrical member having the base portion is detachable, if a plurality of cylindrical members having different base portion heights (axial lengths) are provided, even if the same mold body is used, there is an advantage that reduced-diameter processing portions having different axial lengths can be formed.

[0012] In addition to the above configuration, the pipe processing apparatus according to the present invention "The guide portion has an arcuate rounded portion at the boundary with the single-diameter cylindrical portion" can be adopted.

[0013] In this configuration, since the guide part has a rounded part at the boundary with the single-diameter cylindrical part, the end of the cylindrical pipe deformed to bend inward along the inclination of the guide part can easily enter the space between the inner peripheral surface of the single-diameter cylindrical part and the outer peripheral surface of the small-diameter shaft part beyond the guide part. As a result, the end of the cylindrical pipe can be sufficiently press-fitted to the depth of the inner space of the mold.

Effects of the Invention

[0014] As described above, according to the present invention, it is possible to provide a pipe processing device for processing the end of a pipe and a pipe processing method using the pipe processing device in order to easily connect the pipes linearly while suppressing costs.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0016] Hereinafter, a pipe processing device Ap according to an embodiment of the present invention and a pipe processing method using the pipe processing device Ap will be described with reference to the drawings.

[0017] As shown in FIG. 5, the pipe processing device Ap is a processing device that forms a reduced-diameter processing portion 91b having an outer diameter smaller than that of the non-processing portion 90a at the end of a cylindrical pipe 90 consisting only of a non-processing portion 90a having a single (constant) outer diameter, thereby obtaining a cylindrical pipe 91 having the reduced-diameter processing portion 91b at the end.

[0018] As shown in FIGS. 6(a) and 6(b), by inserting the reduced-diameter processing portion 91b of the cylindrical pipe 91 into the non-processing portion 90a of the cylindrical pipe 90 or the cylindrical pipe 91, it is possible to extremely easily connect cylindrical pipes of the same diameter linearly without requiring a separate joint member.

[0019] The pipe processing device Ap includes a molding die 1, a die support 51 that supports the molding die 1, a holding device 60 that holds the cylindrical pipe 90 to be processed, a positioning device 70 that positions the cylindrical pipe 90 to be processed, and a moving device that relatively separates and approaches the die support 51 with respect to the holding device 60.

[0020] As shown in FIG. 1, the molding die 1 includes a die body 10, a columnar member 20, and a die base 19. The die body 10 has an overall shape of a bottomed cylinder, and includes a single-diameter cylindrical portion 11 having a single (constant) inner diameter and a guide portion 12 whose inner diameter gradually increases from the single-diameter cylindrical portion 11 toward the open end E of the bottomed cylinder. The diameter of the guide portion 12 is set according to the size of the cylindrical pipe 90 to be processed. That is, the diameter of the guide portion 12 is set such that the outer diameter (the outer diameter of the non-processing portion 90a) of the cylindrical pipe 90 to be processed is larger than the minimum diameter of the guide portion 12 and equal to or less than the maximum diameter of the guide portion 12.

[0021] Furthermore, the guide portion 12 is provided with an arcuate rounded portion 13 at the boundary with the single-diameter cylindrical portion 11. More specifically, in the present embodiment, the guide portion 12 excluding the rounded portion 13 forms an angle of 45 degrees with respect to the plane extending the open end E.

[0022] The columnar member 20 extends from the bottom 15 of the mold body 10 toward the open end E in the same axial direction as the mold body 10, and is composed of a base portion 23, a small-diameter shaft portion 21, and a large-diameter portion 22, which are three portions with different outer diameters. The outer diameter of the base portion 23 is substantially equal to the inner diameter of the single-diameter cylindrical portion 11, and it is fixed in a state of being in contact with the bottom 15 of the mold body 10 inside the mold body 10. The outer diameter of the large-diameter portion 22 is smaller than the inner diameter of the single-diameter cylindrical portion 11. The difference between the inner diameter of the single-diameter cylindrical portion 11 and the outer diameter of the large-diameter portion 22 is set to be approximately twice the thickness of the cylindrical pipe 90. The outer diameter of the small-diameter shaft portion 21 is smaller than the outer diameter of the large-diameter portion 22, and the large-diameter portion 22 is fixed to the base portion 23 so that the large-diameter portion 22 is located outside the open end E. That is, the small-diameter shaft portion 21 supports the large-diameter portion 22 with respect to the bottom 15 of the mold body 10 via the base portion 23. The base portion 23, the small-diameter shaft portion 21, and the large-diameter portion 22 are all columnar with the same axial direction, but the small-diameter shaft portion 21 is an elongated columnar shape with an axial length larger than the outer diameter, and the base portion 23 and the large-diameter portion 22 are each a flat columnar shape with an axial length smaller than the outer diameter.

[0023] In this embodiment, the columnar member 20 is detachable from the mold body 10.

[0024] The space between the inner peripheral surface of the mold body 10 and the outer peripheral surface of the small-diameter shaft portion 21 is a space used for processing the end portion of the cylindrical pipe. Among them, the space between the inner peripheral surface of the single-diameter cylindrical portion 11 and the outer peripheral surface of the small-diameter shaft portion 21 is herein referred to as the "inner space S of the cylindrical portion". Since the outer diameter of the base portion 23 is substantially equal to the inner diameter of the single-diameter cylindrical portion 11, the surface on the open end E side of the base portion 23 constitutes the inner end surface 25 of the inner space S of the cylindrical portion.

[0025] The mold base 19 protrudes from the bottom 15 of the mold body 10 to the side opposite to the columnar member 20. The molding die 1 is fixed to the mold support 51 by this mold base 19. The mold support 51 is block-shaped, and the molding die 1 is supported by the mold support 51 so that the axial directions of the mold body 10 and the columnar member 20 are in the horizontal direction. In this embodiment, the mold body 10 is detachable from the mold support 51 via the mold base 19.

[0026] The holding device 60 includes a lower holder 61 fixed to a pedestal (not shown), an upper holder 62 that holds the cylindrical pipe 90 together with the lower holder 61, and a holder lifting device (not shown) that raises and lowers the upper holder 62 with respect to the lower holder 61. The lower holder 61 is a block-shaped member having a concave portion 61r with a semi-circular arc outer shape in cross-section, and the diameter of this semi-circular arc is substantially the same as the outer diameter of the cylindrical pipe 90. The opening of the concave portion 61r of the lower holder 61 faces upward. The upper holder 62 has a shape obtained by turning the lower holder 61 upside down, and the opening of the concave portion 62r having the same shape as the concave portion 61r faces downward (see Fig. 2(b-2)). With such a lower holder 61 and upper holder 62, the cylindrical pipe 90 is held in a state where its axial direction is horizontal.

[0027] As the holder lifting device, a cylinder device that advances and retracts a piston rod by air or oil and raises and lowers the upper holder 62 by the advancement and retraction of the piston rod can be used.

[0028] The positioning device 70 includes a stopper 71 that is a vertical plane, a stopper support 72 that supports the stopper 71, and a stopper lifting device (not shown) that raises and lowers the stopper support 72. As the stopper lifting device, a cylinder device that advances and retracts a piston rod by air or oil and raises and lowers the stopper support 72 by the advancement and retraction of the piston rod can be used.

[0029] The moving device (not shown) may be a device that moves the mold support body away from and close to the holding device that holds the cylindrical pipe, or a device that moves the holding device that holds the cylindrical pipe away from and close to the mold support body. However, in the present embodiment, while fixing the lower holder 61 of the holding device 60 to the gantry as described above, the mold support body 51 is moved away from and close to the holding device 60. Further, as described above, since the holding device 60 holds the cylindrical pipe 90 so that the axial direction is horizontal, the moving device reciprocates the mold support body 51 in the horizontal direction. As the moving device, a cylinder device that advances and retracts the piston rod by air or oil and reciprocates the mold support body 51 by the advance and retraction of the piston rod can be used. Hereinafter, the movement in the direction approaching the holding device 60 of the molding die 1 may be referred to as "forward movement", and the movement in the separating direction may be referred to as "backward movement".

[0030] Next, a pipe processing method using the pipe processing apparatus Ap having the above configuration will be described. First, as shown in FIG. 2(a), the molding die 1 is separated from the holding device 60, and the upper holder 62 is raised in the holding device 60 that does not hold the cylindrical pipe 90. The molding die 1 and the lower holder 61 are arranged such that the axial directions of the bottomed cylindrical die body 10 and the columnar member 20 in the molding die 1 and the upper end of the concave portion 61r of the semicircular arc of the cross section of the lower holder 61 (the central axis of the cylindrical pipe 90 placed in the concave portion 61r) are on the same line (shown in the figure, virtual line L). Further, the positioning device 70 is arranged at a position where the stopper 71 is lifted and lowered via the stopper support 72 between the molding die 1 separated from the holding device 60 and the holding device 60. The stopper support 72 is lowered so that the stopper 71 is positioned on the above-mentioned line L by driving the stopper lifting device of the positioning device 70.

[0031] In this state, as shown in FIGS. 2(b-1) and 2(b-2), the cylindrical pipe 90 is horizontally inserted from the side opposite to the side where the stopper 71 is located with respect to the holding device 60, and the tip thereof is brought into contact with the stopper 71, and then the cylindrical pipe 90 is placed in the concave portion 61r of the lower holder 61.

[0032] Next, as shown in FIGS. 2(c-1) and 2(c-2), lower the upper holder 62 and abut the opening edge of the recess 61r of the lower holder 61 against the opening edge of the recess 62r of the upper holder 62. As a result, the cylindrical pipe is clamped from above and below and held firmly.

[0033] Thereafter, as shown in FIG. 2(d), drive the stopper lifting device of the positioning device 70 to raise the stopper 71 via the stopper support 72. As a result, the tip side of the cylindrical pipe 90 held by the holding device 60 is exposed by a predetermined length toward the molding die 1. The length of the portion where the cylindrical pipe is exposed from the holding device 60 toward the molding die 1 is set to be slightly longer than the axial length of the reduced-diameter processing portion 91b to be formed (for example, 1.2 to 1.6 times the axial length of the reduced-diameter processing portion 91b) by setting the position of the stopper 71 with respect to the holding device 60.

[0034] Next, drive the moving device to advance the molding die 1 via the die support 51 and press-fit the end portion of the cylindrical pipe 90 into the molding die 1 relatively. This operation is performed in one go, but here, the process will be described in order using FIGS. 3(a) to 3(c). Hereinafter, the end portion of the cylindrical pipe 90 may be simply referred to as the "pipe end portion".

[0035] When the tip of the cylindrical pipe 90 abuts against the molding die 1 as the molding die 1 advances, as shown in FIG. 3(a), the abutting position is on the surface of the guide portion 12. This is because, as described above, the outer diameter of the non-processed portion 90a of the cylindrical pipe 90 is larger than the minimum diameter of the guide portion 12 and equal to or less than the maximum diameter of the guide portion 12.

[0036] When the forming die 1 further advances from this state, as shown in Fig. 3(b), the pipe end is guided by the inclination of the guide portion 12 and bends inward while being press-fitted into the forming die 1. Since an arc-shaped rounding portion 13 is formed at the boundary between the single-diameter cylindrical portion 11 and the guide portion 12, the pipe end easily enters the cylindrical inner space S, which is the space between the inner peripheral surface of the single-diameter cylindrical portion 11 and the outer peripheral surface of the small-diameter shaft portion 21, beyond the rounding portion 13. When the pipe end is press-fitted into the forming die 1 in this way, the pipe end is pressed from the outer peripheral surface side and deformed.

[0037] The deformation of the pipe end accompanying such press-fitting is a deformation along the inclination in the guide portion 12, but in the cylindrical inner space S, it is not necessarily a deformation that exactly follows the inner peripheral surface of the single-diameter cylindrical portion 11. Immediately after the pipe end passes through the guide portion 12, an inertial force acts in the direction of the inclination of the guide portion 12, making it easy to separate from the inner peripheral surface of the single-diameter cylindrical portion 11. If it proceeds as it is, a force that contacts the outer peripheral surface of the small-diameter shaft portion 21 and is pushed back acts. Therefore, in the cylindrical inner space S, the pipe end deforms unevenly in a slightly wavy manner. Note that in the drawing, the uneven deformation in the cylindrical inner space S is shown schematically exaggerated.

[0038] The distance that the forming die 1 moves by driving the moving device is set to the distance at which the pipe end reaches the back end surface 25 of the cylindrical inner space S when the forming die 1 is closest to the holding device 60, as shown in Fig. 3(c). Specifically, the distance that the forming die 1 further advances from the position where the tip of the cylindrical pipe 90 abuts on the forming die 1 is set to be slightly shorter than the distance between the extension surface of the open end E in the forming die 1 and the back end surface 25.

[0039] As shown in Fig. 3(c), when the press-fitting of the pipe end into the forming die 1 is completed, for the reasons described above, the deformed pipe end follows the inclination of the guide portion 12, but on the tip side thereof, it does not necessarily follow the inner peripheral surface of the single-diameter cylindrical portion 11 and has a portion deformed unevenly.

[0040] In the pipe processing device Ap of the present embodiment, when the forming die 1 retracts, that is, when it moves away from the holding device 60, the above-mentioned non-uniform deformation is corrected. When the forming die 1 is retracted via the die support 51 by driving the moving device, the pipe end is relatively pulled out from the forming die 1. Although this operation is performed in one go, the process will be described in order using FIGS. 4(a) to 4(c) here.

[0041] As shown in FIG. 4(a), when the pipe end is slightly pulled out from the forming die 1, the large-diameter portion 22 that has been located inside the non-processed portion 90a and has not been in contact with anything comes into contact with the inner peripheral surface of the non-uniformly deformed pipe end.

[0042] As the forming die 1 retracts, the large-diameter portion 22 moves toward the tip of the pipe while pressing the non-uniformly deformed pipe end from the inner peripheral surface side. A pressing force acts on the portion near the portion pressed by the large-diameter portion 22 at the pipe end as if it were being rubbed, but since the single-diameter cylindrical portion 11 exists outside that portion, it is pressed in a state of being sandwiched between the outer peripheral surface of the large-diameter portion 22 and the inner peripheral surface of the single-diameter cylindrical portion 11. As a result, as shown in FIG. 4(b), after the large-diameter portion 22 has passed as the forming die 1 retracts, a reduced-diameter processed portion 91b having an outer diameter substantially equal to the inner diameter of the single-diameter cylindrical portion 11 and an inner diameter substantially equal to the outer diameter of the large-diameter portion 22 is formed.

[0043] As shown in FIG. 4(c), when the pipe end is completely pulled out from the forming die 1, the non-uniform deformation of the pipe end is corrected, and a cylindrical pipe 91 having a uniform reduced-diameter processed portion 91b at the end is obtained.

[0044] If the outer diameter of the reduced-diameter processed portion 91b is less than or equal to the inner diameter of the non-processed portion 90a, the two can be connected. However, if the outer diameter of the reduced-diameter processed portion 91b is made substantially equal to the inner diameter of the non-processed portion 90a, the two can be connected without play, and since it is difficult for dust or water to enter the connection portion from the outside, this is desirable.

[0045] As described above, according to the pipe processing apparatus Ap of the present embodiment, it is possible to form a reduced-diameter portion 91b having a small outer diameter at the end of the cylindrical pipe 90. Since the cylindrical pipe 91 having the reduced-diameter portion 91b can be connected by simply inserting the reduced-diameter portion 91b into the unprocessed portion 90a of the cylindrical pipes 90 and 91 having the same diameter, the connection work is easy. Further, since no joint member for connection is required, the cost can be suppressed.

[0046] Further, since the columnar member 20 is detachable from the mold body 10, it can be replaced when it is damaged such as being worn. Furthermore, in the present embodiment, the columnar member 20 has a base portion 23. When the pipe end is press-fitted into the molding die 1, the back end surface 25 of the inner space S of the cylindrical portion is strongly pressed by the tip of the cylindrical pipe 90 and is likely to be damaged. In the present embodiment, the surface on the opening E side of the base portion 23 constitutes the back end surface 25. Therefore, by replacing the columnar member 20, the easily damaged back end surface 25 can be easily replaced.

[0047] In addition, if a plurality of columnar members 20 having different heights (axial lengths) of the base portion 23 are provided, even if the same mold body 10 is used, reduced-diameter portions 91b having different axial lengths can be formed. Note that if the columnar member 20 is detachable from the mold body 10 and the base portion 23 is detachable from the small-diameter shaft portion 21, by providing base portions 23 having different heights, in the same manner as above, reduced-diameter portions 91b having different axial lengths can be formed using the same mold body 10.

[0048] Also, in the present embodiment, since the mold body 10 is also detachable from the mold support 51 via the mold base 19, the mold body 10 can be easily replaced when it is damaged such as being worn.

[0049] As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and various improvements and design changes are possible without departing from the gist of the present invention as described below.

[0050] For example, in the above, the case where the mold support 51 supporting the mold 1 approaches and separates from the holding device 60 was illustrated. However, the mold support 51 may be configured to be stationary, and the holding device 60 holding the cylindrical pipe 90 may approach and separate from the mold 1.

[0051] Also, in the above, the case where the end portion is machined with the axial direction of the cylindrical pipe 90 to be machined being the horizontal direction was illustrated. However, the same machining is possible even when the axial direction of the cylindrical pipe 90 is the vertical direction. In this case, the direction of movement for the mold 1 to approach and separate relative to the cylindrical pipe 90 held by the holding device 60 also becomes the vertical direction.

[0052] Furthermore, in the above, the case where the columnar member 20 includes the base portion 23 was illustrated. However, it may be a columnar member composed only of the small-diameter shaft portion 21 and the large-diameter portion 22 without including the base portion 23. In this case, the surface on the opening end E side of the bottom portion 15 of the mold body 10 constitutes the inner end surface of the cylindrical portion inner space S.

Explanation of Reference Numerals

[0053] 1 Mold 10 Mold body 11 Single-diameter cylindrical portion 12 Guide portion 13 Rounded portion 15 Bottom portion 20 Columnar member 21 Small-diameter shaft portion 22 Large-diameter portion 23 Base portion Ap Pipe processing device E Opening end S Cylindrical portion inner space

Claims

1. A pipe processing device comprising a molding die for relatively press-fitting an end portion of a cylindrical pipe, wherein the molding die has a bottomed cylindrical die body having a single-diameter cylindrical portion with a constant inner diameter and a guide portion with a gradually increasing inner diameter starting from the single-diameter cylindrical portion, and includes a columnar member extending in the same axial direction as the die body from the bottom of the die body toward the open end side, the columnar member has a large-diameter portion located outside the open end of the die body and having an outer diameter smaller than the inner diameter of the single-diameter cylindrical portion, and includes a small-diameter shaft portion having an outer diameter smaller than that of the large-diameter portion and supporting the large-diameter portion with respect to the bottom of the die body, has a base portion having an outer diameter substantially equal to the inner diameter of the single-diameter cylindrical portion at an end portion opposite to the large-diameter portion, and is detachable from the die body, and includes a plurality of the columnar members having different axial lengths of the base portion, characterized in that it is a pipe processing device.

2. A pipe processing device comprising a molding die for relatively press-fitting an end portion of a cylindrical pipe, wherein the molding die has a bottomed cylindrical die body having a single-diameter cylindrical portion with a constant inner diameter and a guide portion with a gradually increasing inner diameter starting from the single-diameter cylindrical portion, and includes a columnar member extending in the same axial direction as the die body from the bottom of the die body toward the open end side, the columnar member has a large-diameter portion located outside the open end of the die body and having an outer diameter smaller than the inner diameter of the single-diameter cylindrical portion, and includes a small-diameter shaft portion having an outer diameter smaller than that of the large-diameter portion and supporting the large-diameter portion with respect to the bottom of the die body, has a base portion having an outer diameter substantially equal to the inner diameter of the single-diameter cylindrical portion at an end portion opposite to the large-diameter portion, and is detachable from the die body, and the base portion is detachable from the small-diameter shaft portion, A pipe processing apparatus characterized by the following.

3. The guide part has an arcuate rounded part at the boundary with the single-diameter cylindrical part. The pipe processing apparatus according to claim 1 or claim 2, characterized by the above.

4. A pipe processing method using the pipe processing apparatus according to claim 1 or claim 2, By relatively press-fitting the end of a cylindrical pipe having an outer diameter larger than the minimum diameter and less than or equal to the maximum diameter of the guide part into the inside of the forming die from a state where it is in contact with the guide part, after pressing the end of the cylindrical pipe from the outer peripheral surface side, By relatively pulling out the end of the cylindrical pipe from the forming die, and pressing the end of the cylindrical pipe from the inner peripheral surface side by the large-diameter part, A reduced-diameter processing part having an outer diameter substantially equal to the inner diameter of the single-diameter cylindrical part and an inner diameter substantially equal to the outer diameter of the large-diameter part is formed at the end of the cylindrical pipe. A pipe processing method characterized by the above.

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