Pipe working device and pipe working 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 a pipe end, and a pipe processing method using the pipe processing apparatus. [Background technology]

[0002] Conventional methods for connecting pipes in a straight line include welding the ends of the pipes together, forming flanges on the ends of the pipes and connecting the overlapping flanges with bolts, forming threads on the ends of the pipes and connecting them with joint members having threaded grooves, fitting the pipes into both ends of a cylindrical joint member having an inside diameter substantially equal to the outside diameter of the pipes, and fitting the pipes onto both ends of a joint member whose outside diameter is equal to or larger than the inside diameter of the pipes in the center and whose outside diameter gradually decreases toward both ends.

[0003] However, all of these methods have the problem that connection is time-consuming, and when a joint member is used, the number of parts increases, resulting in higher costs. Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above-mentioned circumstances, the present invention has an object to provide a pipe processing device for processing the ends of pipes in order to easily connect pipes in a straight line at reduced cost, and a pipe processing method using the pipe processing device. [Means for solving the problem]

[0005] In order to solve the above problems, the pipe processing device according to the present invention comprises: "A pipe processing device equipped with a forming die into which the ends of a cylindrical pipe are relatively pressed, The mold is a cylindrical mold body having a bottom, the mold body having a single-diameter cylindrical portion with a constant inner diameter and a guide portion whose inner diameter gradually increases from the single-diameter cylindrical portion; a cylindrical member extending from the bottom of the mold body to the open end side in the same axial direction as the mold body; The cylindrical member is a large diameter portion located outward from an open end of the mold body and having an outer diameter smaller than an 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 against the bottom of the mold body.

[0006] The pipe processing device of this configuration is a device for forming a diameter-reduced portion at the end of a cylindrical pipe. By using the pipe processing device of this configuration, a diameter-reduced portion can be formed at the end of a cylindrical pipe by the following pipe processing method. That is, "The end of a cylindrical pipe, the outer diameter of which is greater than the minimum diameter of the guide portion and less than the maximum diameter of the guide portion, is pressed relatively into the inside of the mold while being in contact with the guide portion, and the end of the cylindrical pipe is pressed from the outer peripheral surface side, The end of the cylindrical pipe is relatively pulled out from the mold, and the end of the cylindrical pipe is pressed from the inner circumferential surface side by the large diameter portion, This is a pipe processing method in which a reduced diameter portion is formed at the end of the cylindrical pipe, the reduced diameter portion having an outer diameter approximately equal to the inner diameter of the single diameter cylindrical portion and an inner diameter approximately equal to the outer diameter of the large diameter portion.

[0007] As will be described in detail later, simply pressing the end of a cylindrical pipe into a mold having an inner diameter smaller than the outer diameter of the cylindrical pipe does not allow a reduced diameter portion with uniform outer and inner diameters to be formed, resulting in non-uniform deformation. In contrast, the mold of the pipe processing device of the present invention is provided with a columnar member having a large diameter portion inside a bottomed cylindrical mold body. When the end of the cylindrical pipe pressed into the mold is pulled out relatively from the molded body, the large diameter portion presses the pipe end from the inner peripheral surface side, thereby correcting the non-uniform deformation of the pipe end and forming a reduced diameter portion with uniform outer and inner diameters.

[0008] A cylindrical pipe with a diameter-reduced portion at its end can be connected to a non-reduced portion of a cylindrical pipe of the same diameter simply by inserting the diameter-reduced portion, making the connection easy. In addition, no joint material is required for connection, which helps reduce costs.

[0009] In addition to the above configuration, the pipe processing apparatus according to the present invention further comprises: "The cylindrical member has a base portion at the end opposite to the large diameter portion, the base portion having an outer diameter approximately equal to the inner diameter of the single diameter cylindrical portion, and is detachable from the mold body."

[0010] In this configuration, the cylindrical member is detachable from the mold body, so that it can be replaced if it is damaged, such as worn. Furthermore, in this configuration, the cylindrical member has a base. When the end of the cylindrical pipe is pressed into the mold, the inner end surface of the mold is easily damaged by being strongly pressed by the tip of the pipe. In contrast, in this configuration, the cylindrical member has a base whose inner diameter and outer diameter of the single-diameter tube portion are approximately equal, so that the surface on the open end side of the base constitutes the inner end surface, and therefore the inner end surface, which is easily damaged, can be easily replaced by replacing the cylindrical member.

[0011] In addition, since the cylindrical member with the base is removable, there is an advantage that, if multiple cylindrical members with different base heights (axial lengths) are provided, it is possible to form reduced diameter processed portions with different axial lengths even when using the same mold body.

[0012] In addition to the above configuration, the pipe processing apparatus according to the present invention further comprises: The guide portion may have an arc-shaped rounded portion at the boundary with the single-diameter cylindrical portion.

[0013] In this configuration, because the guide portion has a radius at the boundary with the single-diameter tube portion, the end of the cylindrical pipe that is deformed so as to bend inward along the inclination of the guide portion can easily pass over the guide portion and enter the space between the inner peripheral surface of the single-diameter tube portion and the outer peripheral surface of the small-diameter shaft portion, thereby allowing the end of the cylindrical pipe to be pressed sufficiently deep into the internal space of the molding die. Effect of the Invention

[0014] As described above, according to the present invention, it is possible to provide a pipe processing device that processes the ends of pipes in order to easily connect pipes in a straight line at reduced cost, and a pipe processing method using the pipe processing device. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a cross-sectional view showing the configuration of a forming die provided in a pipe processing apparatus according to one embodiment of the present invention. [Diagram 2] Figures 2(a), 2(b-1), 2(c-1), and 2(d) are explanatory diagrams of the step of positioning a pipe in the pipe processing method, where Figure 2(b-2) is a cross-sectional view taken along line XX and Figure 2(c-2) is a cross-sectional view taken along line YY. [Diagram 3] 3(a) to 3(c) are explanatory views of the process of relatively press-fitting the end of the cylindrical pipe into the molding die. [Figure 4] 4(a) to 4(c) are explanatory views of the process of relatively pulling out the ends of the cylindrical pipe from the forming die. [Diagram 5] FIG. 5 is an explanatory diagram of processing the end of a cylindrical pipe. [Figure 6] 6(a) and 6(b) are explanatory diagrams of the connection between a diameter-reduced processed portion and a non-processed portion of a cylindrical pipe. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0017] As shown in Figure 5, the pipe processing device Ap is a processing device that forms a reduced-diameter processed portion 91b, the outer diameter of which is smaller than that of the non-processed portion 90a, at the end of a cylindrical pipe 90 consisting only of a non-processed portion 90a with a single (constant) outer diameter, to produce a cylindrical pipe 91 having a reduced-diameter processed portion 91b at its end.

[0018] As shown in Figures 6(a) and 6(b), by inserting the reduced diameter processed portion 91b of the cylindrical pipe 91 into the inside of the cylindrical pipe 90 or the non-processed portion 90a of the cylindrical pipe 91, cylindrical pipes of the same diameter can be connected in a straight line very easily without the need for a separate joint member.

[0019] The pipe processing apparatus Ap comprises a forming mold 1, a mold support 51 that supports the forming mold 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 moves the mold support 51 closer and further away from the holding device 60.

[0020] As shown in Fig. 1, the forming die 1 comprises 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, a single-diameter cylinder portion 11 with a single (constant) inner diameter, and a guide portion 12 whose inner diameter gradually increases from the single-diameter cylinder portion 11 toward an open end E of the bottomed cylinder. The diameter of the guide portion 12 is set according to the size of a cylinder 90 to be machined. In other words, the diameter of the guide portion 12 is set so that the outer diameter of the cylindrical pipe 90 to be machined (the outer diameter of the non-machined portion 90a) is larger than the minimum diameter of the guide portion 12 and is equal to or smaller than the maximum diameter of the guide portion 12.

[0021] Furthermore, guide portion 12 has an arc-shaped R portion 13 at the boundary with single-diameter cylindrical portion 11. More specifically, in this embodiment, guide portion 12 excluding R portion 13 forms an angle of 45 degrees with respect to a plane extending from open end E.

[0022] The cylindrical 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 three parts with different outer diameters: a base part 23, a small diameter shaft part 21, and a large diameter part 22. The base part 23 has an outer diameter approximately equal to the inner diameter of the single diameter cylindrical part 11, and is fixed in a state of abutting against the bottom part 15 of the mold body 10 inside the mold body 10. The large diameter part 22 has an outer diameter smaller than the inner diameter of the single diameter cylindrical part 11. The difference between the inner diameter of the single diameter cylindrical part 11 and the outer diameter of the large diameter part 22 is set to approximately twice the thickness of the cylindrical pipe 90. The small diameter shaft part 21 has an outer diameter smaller than the outer diameter of the large diameter part 22, and the large diameter part 22 is fixed to the base part 23 so that the large diameter part 22 is located outward from the open end E. That is, small diameter shaft portion 21 supports large diameter portion 22 against bottom 15 of mold body 10 via base portion 23. Base portion 23, small diameter shaft portion 21, and large diameter portion 22 are all cylindrical with the same axial direction, but small diameter shaft portion 21 is an elongated cylindrical shape whose axial length is longer than its outer diameter, and base portion 23 and large diameter portion 22 are each flat cylindrical shape whose axial length is shorter than its outer diameter.

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

[0024] The space between the inner peripheral surface of the die body 10 and the outer peripheral surface of the small diameter shaft portion 21 is used for machining the end of the cylindrical pipe, and 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 referred to here as the "cylindrical portion inner space S." Since the outer diameter of the base portion 23 is approximately equal to the inner diameter of the single diameter cylindrical portion 11, the surface of the base portion 23 on the open end E side forms the inner end surface 25 of the cylindrical portion inner space S.

[0025] The mold base 19 protrudes from the bottom 15 of the mold body 10 on the side opposite to the cylindrical member 20. The molding die 1 is fixed to a 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 cylindrical member 20 are horizontal. 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 stand (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 relative to the lower holder 61. The lower holder 61 is a block-shaped member having a recess 61r whose cross-sectional shape is a semicircular arc, and the diameter of the semicircular arc is approximately the same as the outer diameter of the cylindrical pipe 90. The lower holder 61 has an opening of the recess 61r facing upward. The upper holder 62 has a shape obtained by turning the lower holder 61 upside down, and has an opening of a recess 62r having the same shape as the recess 61r facing downward (see FIG. 2(b-2)). The lower holder 61 and the upper holder 62 hold the cylindrical pipe 90 with its axial direction horizontal.

[0027] As the holder lifting device, a cylinder device can be used that uses air or oil to advance and retract a piston rod, thereby lifting and lowering the upper holder 62 by the advancement and retraction of the piston rod.

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

[0029] The moving device (not shown) may be a device for moving the mold support closer and farther from the holding device holding the cylindrical pipe, or a device for moving the holding device holding the cylindrical pipe closer and farther from the mold support. In this embodiment, the lower holder 61 of the holding device 60 is fixed to the stand as described above, while the mold support 51 is moved closer and farther from the holding device 60. As described above, the holding device 60 holds the cylindrical pipe 90 so that its axial direction is horizontal, so the moving device reciprocates the mold support 51 in the horizontal direction. As the moving device, a cylinder device can be used that moves a piston rod forward and backward by air or oil, and reciprocates the mold support 51 by the forward and backward movement of the piston rod. Hereinafter, the movement of the casting mold 1 in the direction approaching the holding device 60 may be referred to as "forward", and the movement in the direction away from the holding device 60 may be referred to as "rearward".

[0030] Next, a pipe processing method using the pipe processing apparatus Ap having the above-mentioned configuration will be described. First, as shown in FIG. 2(a), the forming 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 forming die 1 and the lower holder 61 are arranged so that the axial directions of the bottomed cylindrical die body 10 and the columnar member 20 in the forming die 1 and the upper end of the recess 61r of the semicircular cross section of the lower holder 61 (the central axis of the cylindrical pipe 90 placed in the recess 61r) are on the same line (on the imaginary line L in the figure). In addition, the positioning device 70 is arranged in a position where the stopper 71 is raised and lowered via the stopper support 72 between the forming die 1 separated from the holding device 60 and the holding device 60. The stopper lifting device of the positioning device 70 is driven to lower the stopper support 72 so that the stopper 71 is located on the above-mentioned line L.

[0031] In this state, as shown in Figures 2(b-1) and 2(b-2), the cylindrical pipe 90 is inserted horizontally from the side opposite to the side on which the stopper 71 is located relative to the holding device 60, and with its tip abutting the stopper 71, the cylindrical pipe 90 is placed in the recess 61r of the lower holder 61.

[0032] Next, as shown in Figures 2(c-1) and 2(c-2), the upper holder 62 is lowered so that the opening edge of the recess 61r of the lower holder 61 is butted against the opening edge of the recess 62r of the upper holder 62. This causes the cylindrical pipe to be clamped from above and below and held firmly.

[0033] 2(d), the stopper lifting device of the positioning device 70 is driven to lift 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 toward the forming die 1 by a predetermined length. The position of the stopper 71 relative to the holding device 60 is set so that the length of the portion of the cylindrical pipe exposed toward the forming die 1 from the holding device 60 is slightly longer than the axial length of the diameter-reduced portion 91b to be formed (for example, 1.2 to 1.6 times the axial length of the diameter-reduced portion 91b).

[0034] Next, the moving device is driven to move the forming die 1 forward via the die support 51, and the end of the cylindrical pipe 90 is relatively pressed into the forming die 1. This operation is performed in one go, but the process will be explained in order here using Figures 3(a) to 3(c). Below, the end of the cylindrical pipe 90 may be simply referred to as the "pipe end".

[0035] When the tip of the cylindrical pipe 90 comes into contact with the forming die 1 as the forming die 1 advances, the contact position is on the surface of the guide portion 12, as shown in Fig. 3(a). This is because, as described above, the outer diameter of the non-machined portion 90a of the cylindrical pipe 90 is larger than the minimum diameter of the guide portion 12 and is equal to or smaller than the maximum diameter of the guide portion 12.

[0036] When the forming die 1 advances further 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 pressed into the inside of the forming die 1. Because an arc-shaped rounded portion 13 is formed at the boundary between the guide portion 12 and the single-diameter cylindrical portion 11, the pipe end easily passes over the rounded portion 13 and 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. When the pipe end is pressed 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 caused by such press-fitting is along the inclination of the guide portion 12, but in the space S inside the tube, it does not necessarily deform exactly along the inner peripheral surface of the single-diameter tube portion 11. This is because immediately after the pipe end passes through the guide portion 12, the inertial force acts in the direction of the inclination of the guide portion 12, making it easy for the pipe end to separate from the inner peripheral surface of the single-diameter tube portion 11, and if it continues to move forward, it will come into contact with the outer peripheral surface of the small diameter shaft portion 21 and will be pushed back by a force acting on it. Therefore, in the space S inside the tube, the pipe end deforms unevenly, slightly undulating. Note that the drawings show the uneven deformation in the space S inside the tube in an exaggerated manner.

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

[0039] As shown in FIG. 3(c), at the time when the pressing of the pipe end into the inside of the forming die 1 is completed, for the reasons mentioned above, the deformed pipe end follows the slope of the guide portion 12, but further towards the tip side, it does not necessarily follow the inner surface of the single-diameter cylindrical portion 11, and has an unevenly deformed portion.

[0040] In the pipe processing apparatus Ap of this embodiment, the uneven deformation is corrected when the forming die 1 retreats, i.e., when it moves away from the holding device 60. When the forming die 1 is retreated via the die support 51 by driving the moving device, the pipe end is relatively pulled out from the forming die 1. This operation is performed in one go, and the process will be described below in order with reference to Figures 4(a) to 4(c).

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

[0042] As the forming die 1 retreats, the large diameter portion 22 moves toward the tip of the pipe while pressing the unevenly deformed pipe end from the inner peripheral surface side. The pressing force also acts on the portion of the pipe end near the portion pressed by the large diameter portion 22 as if it were dragged, but since the single diameter cylindrical portion 11 exists outside that portion, it is pressed while 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 Figure 4(b), after the large diameter portion 22 has passed as the forming die 1 retreats, a reduced diameter processed portion 91b is formed whose outer diameter is approximately equal to the inner diameter of the single diameter cylindrical portion 11 and whose inner diameter is approximately equal to the outer diameter of the large diameter portion 22.

[0043] As shown in Figure 4(c), when the pipe end is completely pulled out of the forming mold 1, the uneven deformation of the pipe end is corrected, and a cylindrical pipe 91 having a uniformly reduced diameter portion 91b at the end is obtained.

[0044] It should be noted that the two can be connected if the outer diameter of the reduced diameter processed portion 91b is equal to or smaller than the inner diameter of the non-processed portion 90a; however, it is preferable to make the outer diameter of the reduced diameter processed portion 91b approximately equal to the inner diameter of the non-processed portion 90a, as this allows the two to be connected without any rattling and also makes it less likely that dirt or water will enter the connection portion from the outside.

[0045] As described above, the pipe processing device Ap of this embodiment can form a diameter-reduced portion 91b having a small outer diameter at the end of the cylindrical pipe 90. The cylindrical pipe 91 having the diameter-reduced portion 91b can be connected to the non-processed portion 90a of the cylindrical pipes 90 and 91 of the same diameter simply by inserting the diameter-reduced portion 91b, making the connection easy. In addition, since no joint member is required for connection, costs can be reduced.

[0046] In addition, since the cylindrical member 20 is detachable from the mold body 10, it can be replaced if it becomes damaged, such as worn. Furthermore, in this embodiment, the cylindrical member 20 has a base portion 23. When the pipe end is pressed into the forming mold 1, the inner end surface 25 of the cylindrical space S is strongly pressed by the tip of the cylindrical pipe 90 and is likely to be damaged, but in this embodiment, the surface on the open end E side of the base portion 23 constitutes the inner end surface 25. Therefore, by replacing the cylindrical member 20, the inner end surface 25, which is likely to be damaged, can be easily replaced.

[0047] In addition, if multiple cylindrical members 20 with different heights (axial lengths) of the base portions 23 are provided, it is possible to form reduced diameter processed portions 91b with different axial lengths even when using the same mold body 10. If the cylindrical members 20 are detachable from the mold body 10 and the base portions 23 are detachable from the small diameter shaft portion 21, it is possible to form reduced diameter processed portions 91b with different axial lengths using the same mold body 10, as described above, by providing base portions 23 with different heights.

[0048] In this embodiment, the mold body 10 is also detachable from the mold support 51 via the mold base 19, so that the mold body 10 can be easily replaced when it becomes damaged, such as worn.

[0049] The present invention has been described above with reference to preferred embodiments, but the present invention is not limited to the above embodiments, and various improvements and design changes are possible without departing from the spirit of the present invention, as described below.

[0050] For example, in the above example, the mold support 51 supporting the molding die 1 moves towards and away from the holding device 60. However, the mold support 51 may be configured to be immobile, and the holding device 60 holding the cylindrical pipe 90 may be moved towards and away from the molding die 1.

[0051] In the above, an example was given of machining the end portion with the axial direction of the cylindrical pipe 90 to be machined being horizontal, but similar machining is possible even if the axial direction of the cylindrical pipe 90 is vertical. In this case, the direction of movement of the forming die 1 to move closer and farther away from the cylindrical pipe 90 held by the holding device 60 is also vertical.

[0052] Furthermore, in the above, the cylindrical member 20 is illustrated as having the base portion 23, but the cylindrical member may be composed only of the small diameter shaft portion 21 and the large diameter portion 22 without having the base portion 23. In this case, the surface on the open end E side of the bottom portion 15 of the mold main body 10 forms the inner end surface of the cylindrical internal space S. [Explanation of symbols]

[0053] 1 mold 10-inch body 11 Single diameter tube part 12 Information Department 13 R Section 15 Bottom 20 Cylindrical member 21 Small diameter shaft 22 Large diameter section 23 Base Ap Pipe Processing Equipment E Open end S Cylinder inner space

Claims

1. A pipe processing device having a forming die into which an end of a cylindrical pipe is relatively pressed, The mold is a cylindrical mold body having a bottom, the mold body having a single-diameter cylindrical portion with a constant inner diameter and a guide portion whose inner diameter gradually increases from the single-diameter cylindrical portion; a cylindrical member extending from the bottom of the mold body to the open end side in the same axial direction as the mold body; The cylindrical member is a large diameter portion located outward from an open end of the mold body and having an outer diameter smaller than an inner diameter of the single diameter cylindrical portion; a small diameter shaft portion having an outer diameter smaller than that of the large diameter portion and supporting the large diameter portion against the bottom of the mold body; A pipe processing device characterized by:

2. The cylindrical member has a base portion at an end opposite to the large diameter portion, the base portion having an outer diameter substantially equal to the inner diameter of the single diameter cylindrical portion, and is detachably attached to the mold body.

2. A pipe processing apparatus according to claim 1.

3. The guide portion has an arc-shaped rounded portion at the boundary with the single-diameter cylindrical portion.

3. The pipe processing apparatus according to claim 1 or 2.

4. A pipe processing method using the pipe processing apparatus according to claim 1, The end of a cylindrical pipe, the outer diameter of which is greater than the minimum diameter of the guide portion and equal to or less than the maximum diameter of the guide portion, is relatively pressed into the inside of the mold while being in contact with the guide portion, thereby pressing the end of the cylindrical pipe from the outer peripheral surface side, The end of the cylindrical pipe is relatively pulled out from the mold, and the end of the cylindrical pipe is pressed from the inner circumferential surface side by the large diameter portion, A diameter-reduced portion having an outer diameter approximately equal to the inner diameter of the single-diameter cylindrical portion and an inner diameter approximately equal to the outer diameter of the large-diameter portion is formed at the end of the cylindrical pipe. A pipe processing method comprising the steps of:

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