Expansion molds and reduction molds

Abstract

To provide a tube expansion metal mold and a tube contraction metal mold that can prevent seizure between a metal mold and a tube due to frictional heat in association with tube expansion and tube contraction processing.SOLUTION: A tube expansion metal mold comprises: a core member (32) comprising a first axial oil flow channel (83) which extends in an axial direction and is directly or indirectly connected to an oil input part (81), and a first radial oil flow channel (84) which is connected to the first axial oil flow channel (83) and extends to an outer peripheral surface; and outer peripheral ring metal molds (34, 51, 53) comprising a second radial oil flow channel (87) which is directly or indirectly connected to the first radial oil flow channel (84) and extends to the outer peripheral surface, and a first circumferential oil flow channel (88) which is provided in the outer peripheral surface and is connected to the second radial oil flow channel (87).SELECTED DRAWING: Figure 29

Description

Technical Field

[0004] ,

[0001] The present disclosure relates to an expanding die and a reducing die for processing a pipe, particularly a steel pipe, so that its diameter becomes larger (pipe expansion) or smaller (pipe reduction). In particular, when a steel pipe is fitted (or inserted) into the die, the present disclosure relates to an expanding die and a reducing die that can supply lubricating oil to the die in order to reduce frictional resistance and prevent seizure. This application is based on the content of Japanese Patent Application No. 2018-152618 (Japanese Patent Laid-Open No. 2020-25979) filed by the applicant, and discloses a new structure for lubricating oil supply (particularly, refer to the description after FIG. 27 and after [2. Details of the configuration of the oil flow path]).

Background Art

[0002] Conventionally, in order to expand the end of a relatively small-diameter steel pipe such as an automobile fuel pipe, for example, as shown in Japanese Patent Laid-Open No. 2001-179368, the tapered portion at the tip of a punch 2 as a die is pushed into the opening side of the steel pipe 1 (conversely, the opening of the steel pipe 1 is fitted to the tapered portion at the tip of the punch 2 and pushed in), and the diameter of the end portion on the opening side of the steel pipe 1 is enlarged (pipe expansion).

Prior Art Documents

Patent Documents

[0003] [[ID=,22]]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the steel pipe expansion device described in Patent Document 1 above, since the punch 2, which acts as a mold, is an integral component, when the diameter and length of the expanded and deformed portion of the steel pipe are large, such as in the case of steel pipes used for utility poles, the shape and weight of the punch 2 become large, increasing material costs. Furthermore, if it is desired to expand and deform the steel pipe 1 in multiple stages to progressively increase its diameter, it is necessary to prepare multiple types of punch 2, further increasing costs. The same was true when shrinking the steel pipe.

[0005] In this regard, it is conceivable to construct the punch as a mold not as a single piece, but as a combination of multiple pieces. However, even in that case, heat may be generated due to friction between the steel pipe and the mold during the pipe expansion and contraction processes, which can cause seizing between the steel pipe and the mold surface.

[0006] This disclosure provides an expanding die and a shrinking die that can prevent seizing between the die and the pipe due to frictional heat generated during expanding and shrinking processes by reducing frictional resistance, and that can reduce the force required for processing. [Means for solving the problem]

[0007] A first aspect of the present disclosure is a pipe expansion die for processing a pipe (13) to enlarge its diameter, comprising: an axially extending core member (32) comprising: a first axial oil passage (83) directly or indirectly connected to an oil inlet (81); and a first radial oil passage (84) connected to the first axial oil passage (83) and extending to the outer surface; and a second radial oil passage fitted to the outer circumference of the core member (32), having an outer tapered portion (34a, 51a, 53a) at one end, and directly or indirectly connected to the first radial oil passage (84) and extending to the outer surface. An outer ring mold (34, 51, 53) is provided with a second radial oil passage (87) and a first circumferential oil passage (88) provided on the outer circumferential surface and connected to the second radial oil passage (87). When the inner diameter portion of the pipe (13) is pressed in the pushing direction against at least the outer tapered portion (34a, 51a, 53a) of the outer ring mold (34, 51, 53), the diameter of the pipe (13) is expanded, and the space between the inner diameter portion of the pipe (13) and at least a part of the outer ring mold (34, 51, 53) is lubricated by oil from the first circumferential oil passage (88).

[0008] In the first embodiment described above, the lubricant introduced from the oil inlet (81) reaches the outer surface of the outer ring mold (34, 51, 53) via the first axial oil passage (83), the first radial oil passage (84), and the second radial oil passage (87), and then proceeds circumferentially along the outer surface of the outer ring mold (34, 51, 53) via the first circumferential oil passage (88). Furthermore, during the pipe expansion process, the outer surfaces of the outer ring mold (34, 51, 53) rub against each other along the axial direction with the inner diameter portion of the pipe (13). Therefore, according to the first embodiment, lubricant is supplied in the circumferential and axial directions to the outer surface of the outer ring mold (34, 51, 53) that is in contact with the pipe (13) to be expanded, preventing seizure between the pipe expansion mold and the pipe due to frictional heat generated during pipe expansion. Furthermore, according to the first embodiment, the force required for pipe expansion can be reduced by reducing frictional resistance.

[0009] A second aspect of the present disclosure is an expanding pipe mold in which, in the first aspect, a second circumferential oil passage (85) is provided on at least one of the outer circumferential surface of the core member (32) or the inner circumferential surface of the outer ring mold, which is directly or indirectly connected to the first radial oil passage (84).

[0010] In the second embodiment described above, a second circumferential oil passage (85) connected to the first radial oil passage (84) is provided near the outer circumferential surface of the core member (32) and the inner circumferential surface of the outer ring mold. Therefore, according to the second embodiment, lubricant can be supplied in the circumferential direction inside the expansion mold, which can contribute to the supply of lubricant to the outer circumferential surface of the outer ring mold.

[0011] A third aspect of the present disclosure is an expanding pipe mold in which, in the second aspect, a second axial oil passage (86) is provided on at least one of the outer circumferential surface of the core member (32) or the inner circumferential surface of the outer ring mold, and is connected to at least one of the first radial oil passage (84) or the second circumferential oil passage (85).

[0012] In the third embodiment described above, a second axial oil passage (86) is provided near the outer circumferential surface of the core member (32) and the inner circumferential surface of the outer ring mold, connected to at least one of the first radial oil passage (84) or the second circumferential oil passage (85). Therefore, according to the third embodiment, lubricant can be supplied axially inside the tube expansion mold, which can contribute to the supply of lubricant to the outer circumferential surface of the outer ring mold.

[0013] A fourth aspect of the present disclosure is a pipe expansion die in which, in the third aspect described above, a plurality of second circumferential oil passages (85) are provided along the axial direction of the pipe expansion die, and a second axial oil passage (86) traverses the plurality of second circumferential oil passages (85) while connecting them.

[0014] In the fourth embodiment described above, a plurality of second circumferential oil passages (85) are provided near the outer circumferential surface of the core member (32) and the inner circumferential surface of the outer ring mold, and a second axial oil passage (86) is provided so as to traverse these passages. Therefore, according to the fourth embodiment, lubricant can be supplied radially and axially inside the tube expansion mold, and this can contribute to the supply of lubricant to the outer circumferential surface of the outer ring mold.

[0015] A fifth aspect of this disclosure is an expansion mold in which, in the first to fourth aspects described above, the outer peripheral ring mold (34, 51, 53) is composed of a plurality of axially stacked partial outer peripheral ring molds (34, 51, 53).

[0016] In the fifth embodiment described above, a plurality of partial outer ring molds (34, 51, 53) are provided on the outer circumference of the core member (32). Therefore, according to the fifth embodiment, a second radial oil passage (87) and a first circumferential oil passage (88) can be provided in the plurality of partial outer ring molds (34, 51, 53), which can contribute to the supply of lubricant in the axial and radial directions on the outer surface of the outer ring mold.

[0017] A sixth aspect of the present disclosure is an expansion mold in which, in the fifth aspect described above, the second radial oil passage (87) is provided in each of the plurality of partial outer ring molds (34, 51, 53), and a plurality of first circumferential oil passages (88) are provided, each of the plurality of partial outer ring molds (34, 51, 53) and connected to the corresponding second radial oil passage (87) provided in each of the plurality of partial outer ring molds (34, 51, 53).

[0018] In the sixth embodiment described above, each of the multiple partial outer ring molds (34, 51, 53) is provided with a second radial oil passage (87) and a first circumferential oil passage (88). Therefore, according to the sixth embodiment, lubricant can be effectively supplied in the axial and radial directions on the outer surface of the outer ring mold.

[0019] A seventh aspect of this disclosure is an expansion mold in which, in the first to sixth aspects described above, an oil volume adjustment member (102) is provided in the first radial oil passage (84).

[0020] In the seventh embodiment described above, an oil volume adjustment member (102) is provided in the first radial oil passage (84) that supplies lubricant from the core member (32) to the inner surface of the outer ring mold (34, 51, 53). Therefore, according to the seventh embodiment, the amount and speed of lubricant supplied from the core member (32) to the outer ring mold (34, 51, 53) can be adjusted.

[0021] An eighth aspect of the present disclosure is an expansion mold in which, in the first to seventh aspects described above, a plurality of flow path systems are provided, including the oil inlet section (81), the first axial oil flow path (83), and the first radial oil flow path (84).

[0022] In the eighth embodiment described above, the tube expansion mold is provided with multiple flow path systems for supplying lubricant to the outer surface of the outer ring mold. Therefore, according to the eighth embodiment, the supply of lubricant can be effectively carried out.

[0023] A ninth aspect of the present disclosure is a pipe reduction die for processing a pipe (13) to reduce its diameter, comprising: an outer cylindrical member (61) extending in the axial direction, comprising: an 11th axial oil passage (92) connected to an oil inlet (91); and an 11th radial oil passage (93) connected to the 11th axial oil passage (92) and extending to the inner surface; and a 12th radial oil passage (95) having an inner tapered portion (63a, 78a, 79a) at one end and connected to the 11th radial oil passage (93) and extending to the inner surface; and provided on the inner surface, the first The pipe shrinking mold comprises an inner circumferential ring mold (63, 78, 79) having an eleventh circumferential oil passage (96) connected to two radial oil passages (95), wherein when the outer diameter portion of the pipe (13) is pressed in the pushing direction against at least the inner circumferential tapered portion (63a, 78a, 79a) of the inner circumferential ring mold (63, 78, 79), the pipe diameter of the pipe (13) is reduced, and the space between the outer diameter portion of the pipe (13) and at least a part of the inner circumferential ring mold (63, 78, 79) is lubricated by oil from the eleventh circumferential oil passage (96).

[0024] In the ninth aspect described above, the lubricant introduced from the oil introduction portion (91) reaches the inner peripheral surface of the inner peripheral ring dies (63, 78, 79) via the 11th axial oil flow path (92), the 11th radial oil flow path (93), and the 12th radial oil flow path (95), and proceeds circumferentially along the inner peripheral surface of the inner peripheral ring dies (63, 78, 79) via the 11th circumferential oil flow path (96). Further, in the pipe shrinking process, the inner peripheral surfaces of the inner peripheral ring dies (63, 78, 79) are slid against each other along the axial direction with the outer diameter portion of the pipe (13). Therefore, according to the ninth aspect, lubricant is supplied to the inner peripheral surface of the inner peripheral ring dies (63, 78, 79) that comes into contact with the pipe (13) to be pipe-shrunk in the circumferential and axial directions, and seizure between the pipe-shrinking die and the pipe due to frictional heat generated during the pipe shrinking process can be prevented. Further, according to the ninth aspect, the force required for the pipe shrinking process can be reduced by reducing the frictional resistance.

[0025] A tenth aspect of the present disclosure is a pipe-shrinking die in the ninth aspect, wherein at least one of the inner peripheral surface of the outer peripheral cylindrical member (61) and the outer peripheral surface of the inner peripheral ring die is provided with a 12th circumferential oil flow path (94) connected to the 11th radial oil flow path (93).

[0026] In the tenth aspect described above, a 12th circumferential oil flow path (94) connected to the 11th radial oil flow path (93) is provided in the vicinity of the inner peripheral surface of the outer peripheral cylindrical member (61) and the outer peripheral surface of the inner peripheral ring die. Therefore, according to the tenth aspect, lubricant can be supplied circumferentially inside the pipe-shrinking die, which can contribute to the supply of lubricant to the inner peripheral surface of the inner peripheral ring die.

[0027] An eleventh aspect of the present disclosure is a pipe-shrinking die in the tenth aspect, wherein at least one of the inner peripheral surface of the outer peripheral cylindrical member (61) and the outer peripheral surface of the inner peripheral ring die is provided with a 13th axial oil flow path (97) connected to at least one of the 11th radial oil flow path (93) or the 12th circumferential oil flow path (94).

[0028] In the 11th embodiment described above, a 13th axial oil passage (97) is provided near the inner surface of the outer cylindrical member (61) and the outer surface of the inner ring mold, connected to at least one of the 11th radial oil passage (93) or the 12th circumferential oil passage (94). Therefore, according to the 11th embodiment, lubricant can be supplied axially inside the retraction mold, which can contribute to the supply of lubricant to the inner surface of the inner ring mold.

[0029] A twelfth aspect of the present disclosure is a tube shrinking die in which, in the eleventh aspect, a plurality of the twelfth circumferential oil passages (94) are provided along the axial direction of the tube expansion die, and the thirteenth axial oil passages (97) traverse the plurality of the twelfth circumferential oil passages (85) while connecting them.

[0030] In the 12th embodiment described above, a plurality of 12th circumferential oil passages (94) are provided near the inner surface of the outer cylindrical member (61) and the outer surface of the inner ring mold, and a 13th axial oil passage (97) is provided so as to traverse these passages. Therefore, according to the 12th embodiment, lubricant can be supplied radially and axially inside the retraction mold, and can contribute to the supply of lubricant to the inner surface of the inner ring mold.

[0031] A thirteenth aspect of the present disclosure is a tube shrinkage mold in which, in the ninth to twelfth aspects described above, the inner circumferential ring mold (63, 78, 79) is composed of a plurality of axially stacked partial inner circumferential ring molds (63, 78, 79).

[0032] In the 13th embodiment described above, a plurality of partial inner ring molds (63, 78, 79) are provided on the inner circumference of the outer cylindrical member (61). Therefore, according to the 13th embodiment, a 12th radial oil passage (95) and an 11th circumferential oil passage (96) can be provided in the plurality of partial inner ring molds (63, 78, 79), which can contribute to the supply of lubricant in the axial and radial directions on the inner surface of the inner ring mold.

[0033] A fourteenth aspect of the present disclosure is a retractable pipe mold in which, in the thirteenth aspect, the twelfth radial oil passage (95) is provided in each of the plurality of partial inner ring molds (63, 78, 79), and a plurality of eleventh circumferential oil passages (96) are provided, each of the plurality of partial inner ring molds (63, 78, 79) and connected to the corresponding twelfth radial oil passage (95) provided in each of the plurality of partial inner ring molds (63, 78, 79).

[0034] In the 14th embodiment described above, each of the multiple partial inner ring molds (63, 78, 79) is provided with a 12th radial oil passage (95) and an 11th circumferential oil passage (96). Therefore, according to the 14th embodiment, lubricant can be effectively supplied in the axial and radial directions on the inner surface of the inner ring mold.

[0035] A fifteenth aspect of the present disclosure is a retractable pipe mold in which, in the ninth to fourteenth aspects described above, an oil volume adjustment member (106) is provided in the eleventh radial oil passage (93).

[0036] In the 15th embodiment described above, an oil volume adjustment member (106) is provided in the 11th radial oil passage (93) that supplies lubricant from the outer cylindrical member (61) to the outer surface of the inner ring molds (63, 78, 79). Therefore, according to the 15th embodiment, the amount and speed of lubricant supplied from the outer cylindrical member (61) to the inner ring molds (63, 78, 79) can be adjusted.

[0037] A sixteenth aspect of the present disclosure is a pipe shrinkage mold, in which, as in the ninth to fifteenth aspects, a plurality of flow path systems are provided, including the oil inlet section (91), the eleventh axial oil flow path (92), the eleventh radial oil flow path (93), and the twelfth radial oil flow path (95).

[0038] In the 16th embodiment described above, the tube shrinking mold is provided with multiple flow path systems for supplying lubricant to the inner surface of the inner ring mold. Therefore, according to the 16th embodiment, the supply of lubricant can be effectively carried out. [Brief explanation of the drawing]

[0039] [Figure 1] This is a plan view showing the entire pipe expansion or pipe reduction processing apparatus to which the pipe expansion die and pipe reduction die relating to this disclosure are applied. [Figure 2] Figure 1 is a side view of the pipe expansion or reduction processing apparatus shown. [Figure 3] Figure 1 is a front view of the pipe expansion or reduction processing apparatus shown. [Figure 4A] Figures 4A and 4B are a partial plan view showing the tube expansion die portion of the processing apparatus in Figure 1, and an enlarged cross-sectional view along the line 4B-4B in Figure 4A, respectively. [Figure 4B] Figures 4A and 4B are a partial plan view showing the tube expansion die portion of the processing apparatus in Figure 1, and an enlarged cross-sectional view along the line 4B-4B in Figure 4A, respectively. [Figure 5] Figures 5A and 5B are front and side views, respectively, of the pipe clamp of the processing apparatus shown in Figure 1. [Figure 6] Figures 6A and 6B are a front view and a side view, respectively, showing the clamp from Figure 5 in the state of clamping a pipe. [Figure 7] This is an external perspective view of the first embodiment of the tube expansion mold according to this disclosure. [Figure 8] This is a cross-sectional view of the first embodiment of the tube expansion mold described above. [Figure 9] This is a cross-sectional view of the second embodiment of the tube expansion die described above. [Figure 10] This is a cross-sectional view of the third embodiment of the tube expansion mold described above. [Figure 11] Figures 11A and 11B are a longitudinal cross-sectional side view and a front view, respectively, of the outer ring mold of the tube expansion mold described above. [Figure 12] This is a cross-sectional external perspective view showing the first embodiment of the tube shrinkage mold according to this disclosure. [Figure 13] This is a cross-sectional view of the first embodiment of the tube reduction mold described above. [Figure 14] This is a cross-sectional view of the second embodiment of the tube reduction mold described above. [Figure 15] This is a cross-sectional view of the third embodiment of the tube reduction mold described above. [Figure 16]Figures 16A and 16B are a longitudinal cross-sectional side view and a front view, respectively, of the inner ring mold of the tube shrinkage mold described above. [Figure 17-1] Figures 17A to 17G show the process of expanding a pipe using an expansion die, respectively. [Figure 17-2] Figures 17A to 17G show the process of expanding a pipe using an expansion die, respectively. [Figure 18] Figures 18A and 18B show the pipe in its standalone state before the first stage of expansion processing, and the pipe after it has been pressed into the first expansion die, respectively, during the process of expanding the pipe in stages. [Figure 19] Figures 19A and 19B show the pipe in its standalone state before the second stage of processing, and the pipe after it has been pressed into the second expansion die, respectively. [Figure 20] Figures 20A and 20B show the pipe in its standalone state before the third stage of processing, and the pipe after it has been pressed into the third expansion die, respectively. [Figure 21] This diagram shows a pipe after the expansion process has been completed. [Figure 22-1] Figures 22A to 22G show the process of shrinking a pipe using a pipe shrinking die, respectively. [Figure 22-2] Figures 22A to 22G show the process of shrinking a pipe using a pipe shrinking die, respectively. [Figure 23] Figures 23A and 23B show the pipe in its standalone state before the first stage of the pipe shrinking process, and the pipe after it has been pressed into the first pipe shrinking die, respectively. [Figure 24] Figures 24A and 24B show the pipe in its standalone state before the second stage of processing, and the pipe after it has been pressed into the second pipe shrinking die, respectively. [Figure 25] Figures 25A and 25B show the pipe in its standalone state before the third stage of processing, and the pipe after it has been pressed into the third pipe shrinking die, respectively. [Figure 26] This is a diagram showing a pipe after the shrinking process has been completed. [Figure 27]This is a cross-sectional view of the first-stage tube-expanding die, corresponding to Figure 8, in a tube-expanding die to which the oil flow path of this disclosure is applied. [Figure 28] This is an external perspective view of the first-stage tube expansion mold, corresponding to Figure 7. [Figure 29] Figure 28 is an enlarged view of the main part of the flow channel configuration. [Figure 30A] This is an enlarged cross-sectional view taken from 30A to 30A, as indicated by the arrow in Figure 27. [Figure 30B] This is a cross-sectional view taken along the line 30B-30B in Figure 29. [Figure 31] This is an external perspective view of the outer ring mold of the first stage tube expansion mold, corresponding to Figure 11. [Figure 32] This is a plan view of the bottom surface of the mold base, showing the oil injection section provided in the first stage tube expansion mold. [Figure 33A] This is a perspective view showing an oil volume adjustment member located in the first radial oil passage. [Figure 33B] This is a radial cross-sectional view showing the oil volume adjustment member. [Figure 33C] This is an axial cross-sectional view showing the oil volume adjustment member. [Figure 34] This is a cross-sectional view of the first-stage pipe-reducing mold, corresponding to Figure 13, in a pipe-reducing mold to which the oil flow path of this disclosure is applied. [Figure 35] This is a perspective view of the first stage pipe reduction mold, shown in cross-section, corresponding to Figure 12. [Figure 36] Figure 35 is an external perspective view showing the inner surface of the outer cylindrical mold, obtained by rotating the first-stage tube reduction mold shown in Figure 35 90 degrees around its central axis and removing a portion of the inner ring mold. [Figure 37] Figure 36 is an enlarged view of the main part of the flow path configuration. [Figure 38A] This is an enlarged cross-sectional view taken along the line 38A-38A in Figure 34. [Figure 38B] This is a cross-sectional view taken along the line 38B-38B in Figure 37. [Figure 39] This is an external perspective view of the inner ring mold of the first stage tube reduction mold, corresponding to Figure 16. [Figure 40A]This is a perspective view showing an oil volume adjustment member positioned in the 11th axial oil passage. [Figure 40B] This is a cross-sectional view showing the operation of the oil volume adjustment member. [Figure 40C] This is a cross-sectional view showing the operation of the oil volume adjustment member. [Modes for carrying out the invention]

[0040] Hereinafter, embodiments of the tube expansion dies, tube shrinking dies, and tube expansion or shrinking processing apparatus to which they are applied will be described with reference to the drawings. For the sake of convenience, the basic configuration of the tube expansion dies and tube shrinking dies and the processing operations using them will be described first, and then the details of the configuration of the oil passages provided in the tube expansion dies and tube shrinking dies will be described.

[0041] [1. Basic configuration of tube expansion and tube reduction dies and processing operations using them] Figures 1-26 will be used to explain the basic structure of the mold and the machining operations using it. For the sake of simplicity, the oil flow path will not be mentioned here.

[0042] Figures 1 to 3 are a plan view, a side view, and a front view, respectively, showing the entire pipe expansion or pipe reduction apparatus to which the pipe expansion die and pipe reduction die according to this disclosure are applied.

[0043] In each figure, the pipe expansion or reduction processing apparatus 1 generally comprises a steel pipe processing section 2, a loading table 3 for loading steel pipes (hereinafter referred to as pipes) 13, and a loading table 4 for unloading them. Note that the pipes 13 are not limited to steel pipes, but may be made of other metal materials such as copper or aluminum.

[0044] The steel pipe processing section 2 includes a frame 5, a left-side support 7 that supports the pipe pressing hydraulic cylinder 6 on the left side of the figure, a right-side support 9 that supports the release ring pressing hydraulic cylinder 8 on the right side of the figure, and multiple clamps 10 in an intermediate position (see Figure 5). An extension shaft 11 is attached to the cylinder rod 6a of the left-side hydraulic cylinder 6, and a pressing shaft 12 is attached to the cylinder rod 8a of the right-side hydraulic cylinder 8. Multiple types of extension shafts 11 with different lengths are provided to accommodate changes in the length of the pipe 13.

[0045] Reference numeral 13 denotes a steel pipe (hereinafter referred to as "pipe") used for utility poles, etc., of a predetermined length to be expanded or reduced in length. It is placed on a plurality of feed rollers 14 at an upper position of the frame 5 and comes into contact with the extension shaft 11 as the feed rollers 14 rotate. Subsequently, when the pipe 13 is clamped by the clamp 10, the feed rollers 14 move downward to allow processing of the clamped pipe 13.

[0046] 15 is a pipe expansion die, which is mounted on a die mounting base plate 17 that is provided so as to be able to reciprocate relative to the right-side frame 9 in a direction perpendicular to the axial direction of the steel pipe processing section 2 (see Figures 4A and 4B), and comprises a first-stage pipe expansion die 15A, a second-stage pipe expansion die 15B, and a third-stage pipe expansion die 15C. Each die 15A to 15C extends horizontally and is arranged at a predetermined pitch in the vertical direction when viewed in the plan view (Figure 1).

[0047] 16 is a release ring used in the tube expansion mold 15, and it has three release rings 16A to 16C, each of which is fitted into the base portion of each stage of the tube expansion mold 15A to 15C as described later. (See Figures 7 to 10) Reference numeral 21 denotes a tube shrinking mold, also mounted on the mold mounting base plate 17 of the right-side frame 9, and comprises a first-stage tube shrinking mold 21A, a second-stage tube shrinking mold 21B, and a third-stage tube shrinking mold 21C. Each of the tube shrinking molds 21A to 21C extends horizontally and is arranged at a predetermined pitch when viewed in a plan view (Figure 1).

[0048] As shown in Figures 5A and 5B, the clamp 10 comprises a pair of clamp arms 10A and 10B pivotally mounted on the base 22 of the frame 5. As the cylinder rod 24 of the hydraulic cylinder 23 moves upward, the push plate 27 moves upward, and the clamp arms 10A and 10B rotate in the closing direction via the roller follower 28 to clamp the pipe 13. (See Figures 6A and 6B) In Figure 2, reference numeral 26 denotes a segmented restraining rod, which restrains the pair of support frames 7 and 9 to prevent them from collapsing and deforming during pipe expansion or contraction processing, and the tension can be adjusted by the nut 26a.

[0049] Next, the details of the tube expansion die will be explained using Figures 7 to 10. In Figures 7 and 8, the first-stage tube expansion die 15A comprises a disc-shaped die base 31, a cylindrical core die 32, a first tip die 33A, and a plurality of outer ring dies 34A to 34E (outer diameter dimension D1) fitted to the core die 32 between the die base 31 and the first tip die 33A. The core die 32 is formed by combining two partial core dies 32A and 32B stacked axially for ease of machining, but it is not limited to this, and may be a single component or a combination of three or more core dies. The die base 31, partial core dies 32A and 32B, and the first tip die 33A are firmly fixed together by countersunk bolts 36 to 38. Note that 35 is a collar fitted to the base of the core die 32A.

[0050] Here, the tapered portion at the tip of the tip mold 33A, which has a relatively large taper angle, is a guide portion 33a1 that guides the pipe 13 when it is fitted and inserted into the tip mold 33A, and the tapered portion at the base, which has a relatively small taper angle, is the part where the pipe 13 is first expanded.

[0051] Furthermore, the outer diameter dimension D1 of the first-stage pipe expansion die 15A is not the same across multiple outer ring dies 34A to 34E, but rather forms an outer tapered portion 34a with a slight taper angle (for example, 0.3 degrees to 8.0 degrees) where the outer diameter gradually increases from the tip of the die towards the base. This allows the pipe 13 after expansion to easily escape from the outer circumference of the first-stage pipe expansion die 15A. The same applies to the second and third-stage pipe expansion dies 15B and 15C, which will be described later.

[0052] Furthermore, for the first-stage tube expansion die 15A, the tip die 33A and outer ring die 53, which require high hardness, are made of SKD11 (JIS standard) material that has been tempered at high temperature, and the outer surface has been mirror-finished, followed by a low-temperature TIC coating treatment to achieve an arithmetic mean roughness Ra of, for example, 0.1 or less. The tip die 33A and outer ring die 53 are not limited to the above material and may be made of materials such as cemented carbide with high hardness, and may be hardened by other hardening treatments (hardening may be applied not only to the surface but also to areas other than the surface) in addition to the low-temperature TIC coating treatment. The core die 32 is formed from, for example, S45C (JIS standard) hardened and tempered material. The same applies to the second and third-stage tube expansion dies 15B and 15C described below. The low-temperature TIC coating treatment described above is a process in which TIC (titanium carbide) is deposited onto the surface of steel materials, etc., at a low temperature of 400 to 600°C using the CVD method or PVD method. This improves the wear resistance and corrosion resistance of steel materials and enhances their release properties from resins.

[0053] Reference numeral 40 denotes a contact pin attached to the release ring 16A by bolt 41, which is pressed to the left in the figure by the pressing shaft 12 of the cylinder rod 8a of the hydraulic cylinder 8, as will be described later. As a result, the release ring 16A is guided by the guide rod 42 (fixed to the mold base 31) that passes through its through hole 16a and slides in the same direction, separating the pipe 13 after the pipe expansion process is completed from the mold 15A.

[0054] In Figure 7, 43 is a proximity detection device that detects the position of the release ring 16A, for example, by magnetic induction, and comprises a fixedly positioned sensor 44 and a dog 45 attached to the release ring 16A.

[0055] Next, in Figure 9, the second-stage tube expansion mold 15B has a configuration almost identical to that of the first-stage tube expansion mold 15A, but the second tip mold 33B has different taper angles and diameter dimensions for the two-stage outer peripheral tapered sections 33b1 and 33b2 compared to the corresponding sections of the first tip mold 33A. It also includes multiple outer peripheral ring molds 51A to 51E (outer diameter dimension D2), and this outer diameter dimension D2 is larger than the outer diameter dimension D1 of the outer peripheral ring mold 34 (D2 > D1), forming an outer peripheral tapered section 51a. Note that 16B is a release ring and 52 is a collar.

[0056] Next, in Figure 10, the third-stage tube expansion die 15C has a configuration almost identical to the previous tube expansion dies 15A and 15B, but the third tip die 33C has a taper angle and diameter dimension of the outer circumference tapered portion 33c that differs from the dimensions of the corresponding parts of the previous tip dies 33A and 33B. It also includes multiple outer circumference ring dies 53A to 53E (outer diameter dimension D3), and this outer diameter dimension D3 is larger than the outer diameter dimension D2 of the outer circumference ring die 51 (D3 > D2), forming an outer circumference tapered portion 53a. Note that 16C is a release ring and 54 is a collar. Furthermore, the third tip die 33C of the third stage expansion die 15C does not have a guide portion like the guide portions 33a1 and 33b1 of the tip dies 33A and 33B of the first and second stage expansion dies 15A and 15B. This is because the end of the pipe 13 has already been expanded to some extent by processing with the first and second stage expansion dies 15A and 15B, so it can be fitted well into the third tip die 33C even without a guide portion on the tip side of the third tip die 33C. The same applies to the third tip die 62C of the third stage contraction die 21C (see Figure 15), which will be described later.

[0057] Furthermore, since the outer tapered portions 33a2, 33b2, and 33c of the tip molds 33A to 33C and the outer tapered portions 34a, 51a, and 53a of the outer ring molds 34, 51, and 53 have different taper angles (for example, the taper angle of the former is larger than that of the latter), the pipe 13 can be expanded to a predetermined diameter of the fitting portion by the former outer tapered portions 33a2, 33b2, and 33c, and then a predetermined taper angle can be applied to the fitting portion by the latter outer tapered portions 34a, 51a, and 53a. However, in some cases, the taper angles of the tip molds 33A to 33C and the outer ring molds 34, 51, and 53 may be the same. The same applies to the relationship between the inner tapered portions of the tip cylindrical mold 62 and the inner ring molds 63, 78, and 79 of the pipe shrinking mold described later.

[0058] Furthermore, the point at which the taper angle values ​​of the outer tapered portion of the tip mold 33 and the outer tapered portions of the outer ring molds 34, 51, and 53 switch to different values ​​is not limited to the boundary between the tip mold 33 and the outer ring mold 34, but may also be a point within the axial dimension range of the tip mold 33, or a point within the axial dimension range of each of the outer ring molds 34, 51, and 53. The same applies to the relationship between the tip cylindrical mold 62 and the inner tapered portions of the inner ring molds 63, 78, and 79 of the tube shrinking mold, which will be described later.

[0059] Furthermore, the cross-sectional shape of the outer tapered portion of the tip mold 33 and the outer ring molds 34, 51, and 53 is not limited to a straight line, but may be a convex curve or a concave curve. The same applies to the inner tapered portions of the tip cylindrical mold 62 and the inner ring molds 63, 78, and 79 of the tube shrinking mold.

[0060] Figures 11A and 11B show the outer ring mold 34 (51, 53). Next, the details of the pipe shrinkage mold will be explained using Figures 12 to 15. In Figures 12 and 13, the first-stage tube reduction mold 21A comprises a disc-shaped mold base 31A, a cylindrical outer circumferential mold 61, a first tip mold 62A, and a plurality of inner circumferential ring molds 63A to 63D (inner diameter dimension d1) inserted and fitted into the outer circumferential mold 61 between the mold base 31A and the first tip mold 62A. The outer circumferential mold 61 is formed by combining two partial outer circumferential molds 61A and 61B stacked axially for ease of machining, but it is not limited to this, and may be a single component or a combination of three or more partial outer circumferential molds. The mold base 31A, the partial outer circumferential molds 61A and 61B, and the first tip mold 62A are firmly fixed together by countersunk bolts 65 to 67. Note that 71 is a fixed cylinder that houses the release pressing member 73, which will be described later, and is fixed to the mold base 31A by bolts 72.

[0061] Here, the tip-side tapered portion of the tip mold 62A with a relatively large taper angle is a guide portion 62a1 that guides the pipe 13 when the pipe 133 is fitted and inserted into the tip mold 62A, while the inner circumference tapered portion 62a2 with a relatively small taper angle at the base is the part where the pipe 13 is first reduced in size.

[0062] Furthermore, the inner diameter dimension d1 of the first-stage pipe reduction mold 21A is not the same across the multiple inner ring molds 63A to 63D, but rather forms an inner tapered section 63a with a slight taper angle (for example, 0.3 degrees to 8.0 degrees) where the inner diameter gradually decreases from the tip of the mold towards the base. This allows the pipe 13 after pipe reduction processing to easily escape from the inner circumference of the first-stage pipe reduction mold 21A. The same applies to the second and third-stage pipe reduction molds 21B and 21C, which will be described later.

[0063] Furthermore, as the material of the first-stage pipe-reducing die 21A, the tip die 62A and the inner peripheral ring die 63 that require high hardness are made of SKD11 (JIS standard) material, which is subjected to high-temperature annealing treatment and the inner peripheral surface is mirror-finished, and then subjected to low-temperature TIC coating treatment so that the arithmetic mean roughness Ra is, for example, a value of 0.1 or less. The tip die 62A and the inner peripheral ring die 63 are not limited to the above materials and may also be made of materials such as cemented carbide having high hardness, and are not limited to low-temperature TIC coating treatment and may also be other hardening treatments (not only the surface but also the parts other than the surface may be hardened). The outer peripheral cylindrical die 61 is formed of, for example, quenched and tempered material of S45C (JIS standard). The same applies to the following second-stage and third-stage pipe-reducing dies 21B and 21C.

[0064] 73 is a die release pressing member in which a base plate 74, an intermediate ring 75, and a pressing plate 76A (outer diameter dimension d1) are fixed by bolts 77A and 77B. With the pressing plate 76A fitted to the inner periphery of the inner peripheral ring die 63, it is guided by the fitting of a key 78 and a key groove 74a and can reciprocally slide in the left-right direction in the figure. When this die release pressing member 73 is pressed by the pressing shaft 12 and slides leftward, the pipe 13 after the pipe-reducing process is separated from the die 21A. Further, 43 is a magnetic induction type detection device for detecting the position of the die release pressing member 73, and includes a sensor 44 disposed on the fixed cylinder 71 and a dog 45 attached to the die release pressing member 73.

[0065] Next, in FIG. 14, the second-stage pipe-reducing die 21B has substantially the same configuration as the first-stage pipe-reducing die 21A, but the second tip die 62B has different taper angles and diameter dimensions of the two-stage inner peripheral taper portions 62b1 and 62b2 from the dimensions of the corresponding portions of the first tip die 62A, and includes a plurality of inner peripheral ring dies 78A to 78D (inner diameter dimension d2). This inner diameter dimension d2 forms an inner peripheral taper portion 78a that is smaller than the inner diameter dimension d1 of the previous inner peripheral ring die 63 (d2 < d1). The outer diameter dimension of the pressing plate 76B of the die release pressing member 73 is also d2.

[0066] Next, in FIG. 15, the third-stage necking die 21C has substantially the same configuration as the previous necking dies 21A and 21B, but the third tip die 62C has a taper angle and a diameter dimension of the inner peripheral taper portion 62c that are different from the dimensions of the corresponding portions of the previous tip dies 62A and 62B, and also includes a plurality of inner peripheral ring dies 79A to 79D (inner diameter dimension d3). This inner diameter dimension d3 forms an inner peripheral taper portion 79a that is smaller than the inner diameter dimension d2 of the inner peripheral ring die 78 (d3 < d2). Also, the outer diameter dimension of the pressing plate 76C of the mold release pressing member 73 is also d3.

[0067] Note that FIGS. 16A and 16B show the inner peripheral ring dies 63 (78, 79). Next, the procedure for processing the pipe 13 will be described. First, in FIGS. 1 to 3, the pipe 13 is carried from the pipe loading table 3 to the steel pipe processing section 2 and reaches a coaxial position between the extension shaft 11 and the first-stage expanding die 15A and is placed on the feed roller 14. By the rotation of the feed roller 14, it is axially moved in the left direction in the figure and abutted against the extension shaft 11. Next, the clamp arms 10A and 10B of the five clamps 10 are rotationally closed by the hydraulic cylinder 23 to clamp the pipe 13 while lifting it slightly by a preset machining centering position dimension of the pipe 13. At this time, the feed roller 14 is separated from the pipe.

[0068] Subsequently, first, the procedure for processing the pipe 13 using the expanding die will be described using FIGS. 17A to 17E. FIG. 17A shows a state where the pipe 13 and the first-stage expanding die 15A are centered coaxially with each other.

[0069] Subsequently, in FIG. 17B, the pressing shaft 12 is moved leftward in the figure by the hydraulic cylinder 8 to move the mold release ring 16A in the same direction by a predetermined distance m via the contact pin 40. As a result, the dog 45 of the detection device 43 reaches a position where it is disengaged from the sensor 44.

[0070] Subsequently, in FIG. 17C, the pressing shaft 12 is moved back rightward in the figure. Next, in Figure 17D, the pipe 13 is pressed and moved to the right in the figure by the hydraulic cylinder 6 via the extension shaft 11 and integrally with the clamp 10, so that the tip of the pipe 13 rides onto the outer tapered portions 33a1 and 33a2 of the tip die 33A of the first stage pipe expansion die 15A, and then onto the outer tapered portion 34a of the outer ring die 34, and the pipe expansion process begins.

[0071] Next, in Figure 17E, the tip of pipe 13 comes into contact with the release ring 16A. Next, in Figure 17F, the pipe 13 is pushed further to the right along with the release ring 16A, and when the dog 45 of the detection device 43 is in the position corresponding to the sensor 44, the operation of the hydraulic cylinder 6 is stopped by the detection signal, and the pipe expansion process of the pipe 13 is completed. At this time, after the clamp on the pipe by the clamp 10 is released, the cylinder rod 6a of the left hydraulic cylinder 6 moves back approximately 200 mm to the left along with the extension shaft 11.

[0072] Next, in Figure 17G, the pressing shaft 12 is moved to the left by the hydraulic cylinder 8, causing the release ring 16A to move a predetermined distance in the same direction via the contact pin 40. As a result, the expanded pipe 13 is separated from the first stage expansion die 15A, completing the first stage of processing.

[0073] Next, the procedure for gradually expanding the pipe 13 from the first to the third stage using the first to third stage molds 15A to 15C in sequence will be explained using Figures 18 to 21. In this case, the switching of the first to third stage molds 15A to 15C for the pipe 13 is performed by moving the mold mounting base plate 17 to which each mold 15A to 15C is attached in a direction perpendicular to the axis of the processing section 2, and then sequentially switching to a position concentric with the axis, as shown in Figure 1. Of course, the process is not limited to three stages; it may also be one or two stages, or four or more stages.

[0074] First, Figures 18A and 18B show the state of pipe 13A before the start of the first stage of pipe expansion, and the state of pipe 13B and the first stage pipe expansion die 15A at the end of the first stage of pipe expansion, respectively. These correspond to the left portion of Figure 17A and Figure 17F, which have already been explained.

[0075] Next, Figures 19A and 19B show the state of pipe 13B (corresponding to pipe 13B in Figure 18B) before the start of the second stage of pipe expansion, and the state of pipe 13C and the second stage pipe expansion die 15B (having outer tapered sections 33b2 and 51a) at the end of the second stage of pipe expansion, respectively. The inner diameter dimension D1' on the right end of pipe 13B is almost the same as the outer diameter dimension D1 of the outer ring die 34 of the first stage pipe expansion die 15A, but is slightly smaller than D1 due to springback. (D1') <D1) Next, Figures 20A and 20B show the state of pipe 13C (corresponding to pipe 13C in Figure 19B) before the start of the third stage of pipe expansion, and the state of pipe 13D and the third stage pipe expansion die 15C (having outer tapered sections 33c and 53a) at the end of the third stage of pipe expansion, respectively. The inner diameter dimension D2' on the right end of pipe 13C is almost the same as the outer diameter dimension D2 of the outer ring die 51 of the second stage pipe expansion die 15B, but is slightly smaller than D2 due to springback. (D2') <D2) Finally, Figure 21 shows the final expanded pipe 13D (corresponding to pipe 13D in Figure 20B), where the inner diameter dimension D3' on the right end of pipe 13D is almost identical to the outer diameter dimension D3 of the outer ring mold 53 of the third stage expansion mold 15C, but is slightly smaller than D3 due to springback. (D3') <D3)(D1´<D2´<D3´) After the pipe expansion process is complete, the pipe 13 moves axially back to the position shown in Figures 1 and 2. The clamp 10 releases the pipe, and it is discharged from the discharge table 4. Then, the next pipe 13 is brought into the processing unit 2, and the same process is repeated.

[0076] Next, the procedure for processing the pipe 13 using a pipe shrinking die will be explained using Figures 22A to 22G. In Figures 1 to 3, when the pipe 13 is loaded from the loading table 2 into the steel pipe processing section 2, the pipe shrinking dies 21A to 21C are sequentially positioned at the axial position of the processing section 2 instead of the pipe expansion die 15, but the operation of the clamp 10, etc., remains the same. Note that the processing is not limited to three stages; it may also be one or two stages, or four or more stages.

[0077] Figure 22A shows the state in which the pipe 13 and the first stage pipe reduction mold 21A are centered coaxially with each other. Next, in Figure 22B, the pressing shaft 12 is moved to the left by the hydraulic cylinder 8 and comes into contact with the release pressing member 73, moving it a predetermined distance n in the same direction. As a result, the dog 45 of the detection device 43 moves to a position away from the sensor 44.

[0078] Next, in Figure 22C, the pressing shaft 12 is moved back to the right in the figure. Next, in Figure 22D, the pipe 13 is pressed and moved to the right by the hydraulic cylinder 6, and the tip of the pipe 13 is successively pressed against the inner tapered portions 62a1 and 62a2 of the tip mold 62A of the first stage pipe shrinking mold 21A, and then against the inner tapered portion 63a of the inner ring mold 63, thereby initiating the pipe shrinking process.

[0079] Next, in Figure 22E, the tip of the pipe 13 comes into contact with the pressing plate 76A of the release pressing member 73. At this time, after the clamp on the pipe by the clamp 10 is released, the cylinder rod 6a of the left hydraulic cylinder 6 moves back approximately 200 mm to the left in the figure along with the extension shaft 11.

[0080] Next, in Figure 22F, the pipe 13 is pushed further to the right along with the release pressing member 73, and when the dog 45 of the detection device 43 is in the position corresponding to the sensor 44, the operation of the hydraulic cylinder 6 is stopped by the detection signal, and the pipe shrinking process of the pipe 13 is completed.

[0081] Next, in Figure 22G, the pressing shaft 12 is moved to the left by the hydraulic cylinder 8 and comes into contact with the release pressing member 73, moving it a predetermined distance to the left. As a result, the pipe 13 that has been processed to shrink is separated from the first stage shrinking die 21A, and the first stage of processing is completed.

[0082] Next, the procedure for gradually reducing the pipe 13 from the first to the third stage using the first to third stage molds 21A to 21C in sequence will be explained using Figures 23 to 26. In this case, the switching of the first to third stage reduction molds 21A to 21C for the pipe 13 is done by moving each mold 21A to 21C in a direction perpendicular to the axis of the processing section 2, and then sequentially switching to a position concentric with the axis, as shown in Figure 1. Of course, the process is not limited to three stages; it can also be done in two stages or four or more stages.

[0083] First, Figures 23A and 23B show the state of pipe 13A' before the start of the first stage of pipe reduction processing, and the state of pipe 13B' and the first stage pipe reduction mold 21A at the end of the first stage of pipe reduction processing, respectively. These correspond to the left portion of Figure 22A and Figure 22F, which have already been explained.

[0084] Next, Figures 24A and 24B show the state of pipe 13B' (corresponding to pipe 13B' in Figure 23B) before the start of the second stage of pipe reduction processing, and the state of pipe 13C' and the second stage pipe reduction mold 21B (which has inner tapered sections 62b2 and 78a) at the end of the second stage of pipe reduction processing. The outer diameter dimension d1' on the right end of pipe 13B' is almost the same as the inner diameter dimension d1 of the inner ring mold 63 of the first stage pipe reduction mold 21A, but is slightly larger than d1 due to springback. (d1'>d1) Next, Figures 25A and 25B show the state of pipe 13C' (corresponding to pipe 13C' in Figure 24B) before the start of the third stage of pipe reduction processing, and the state of pipe 13D' and the third stage pipe reduction mold 21C (which has inner tapered sections 62c and 79a) at the end of the third stage of pipe reduction processing. The outer diameter dimension d2' on the right end of pipe 13C' is almost the same as the inner diameter dimension d2 of the inner ring mold 78 of the second stage pipe reduction mold 21B, but is slightly larger than d2 due to springback. (d2'>d2) Finally, Figure 26 shows the final reduced-size pipe 13D' (corresponding to pipe 13D' in Figure 25B). The outer diameter d3' at the right end of pipe 13D' is almost identical to the inner diameter d3 of the inner ring mold 79 of the third-stage reduced-size mold 21C, but is slightly larger than d3 due to springback. (d3'>d3)(d1'>d2'>d3') After the pipe shrinking process is complete, the pipe 13 moves axially back to the position shown in Figures 1 and 2. The clamp 10 releases the pipe, and it is discharged from the discharge table 4. Then, the next pipe 13 is brought into the processing unit 2, and the same process is repeated.

[0085] In the above pipe expansion embodiment, when the inner diameter of the pipe 13 is sequentially expanded by the tip die 33 and the outer ring dies 34, 51, and 53, if the first taper angle of the outer tapered portion 33a to 33c of the tip die 33 and the second taper angle of the outer tapered portion 34a, 51a, and 53a of the outer ring dies 34, 51, and 53 are set to different values, it is possible to form outer tapered portions with two different taper angle values ​​for a single pipe 13. In some cases, it is also possible to form outer tapered portions with three or more taper angle values. The same applies to pipe shrinking.

[0086] Furthermore, in the above pipe expansion process, the inner diameter of the pipe 13 is sequentially expanded by the outer tapered portions 33a to 33c of the tip die 33 and the outer tapered portions 34a, 51a, and 53a of the outer ring dies 34, 51, and 53. However, this is not limited to this, and in some cases, the tip die 33 may only serve to guide the pipe 13, and the pipe expansion function may be performed only by the outer tapered portions 34a, 51a, and 53a of the outer ring dies 34, 51, and 53. Similarly, in the above pipe shrinking process, the pipe shrinking function of the pipe 13 may be performed only by the inner tapered portions 63a, 78a, and 79a of the inner ring dies 63, 78, and 79.

[0087] Furthermore, in the above embodiment of pipe expansion, the first to third stage pipe expansion dies 15A to 15C were applied sequentially to one pipe 13 to complete the pipe expansion process, and then the expansion process for the next pipe 13 was performed. However, the process is not limited to this, and multiple pipes 13 may be expanded first using the first stage pipe expansion die 15A, then the multiple pipes 13 may be expanded using the second stage pipe expansion die 15B, and then the multiple pipes 13 may be expanded using the third stage pipe expansion die 15C. The same applies to pipe shrinking.

[0088] [2. Details of the oil flow path configuration] The oil passages provided in the pipe expansion and pipe contraction dies described above will now be explained. The oil passages in this disclosure are passages for supplying lubricants such as lubricating oil and grease to reduce frictional resistance when processing the pipe 13 using the die, thereby preventing seizure between the die and the pipe 13 due to frictional heat generated during processing, and reducing the force required for processing. The lubricants are not particularly limited, and any substance that reduces resistance between the die and the pipe 13 can be appropriately selected. In the following explanation, lubricating oil will be used as an example, but the lubricating oil in this disclosure also includes grease and other lubricants.

[0089] (2-1. Oil passages provided in the tube expansion mold) The oil passages provided in the tube expansion die according to this disclosure will now be described. Figure 27 is a cross-sectional view of the first stage tube expansion die 15A (a first embodiment of the tube expansion die according to this disclosure), corresponding to Figure 8, in a tube expansion die to which the oil passages are applied. Figure 28 is an external perspective view of the first stage tube expansion die 15A, corresponding to Figure 7. Figure 29 is an enlarged view of the main part of the passage configuration in Figure 28. Figure 30A is an enlarged cross-sectional view taken from arrow 30A to 30A in Figure 27. Figure 30B is a cross-sectional view taken from arrow 30B to 30B in Figure 29. Figure 31 is an external perspective view of the outer ring die 34 of the first stage tube expansion die 15A, corresponding to Figure 11. Figure 32 is a plan view of the bottom surface of the die base 31 showing the oil inlet sections 81a to 81c provided in the first stage tube expansion die 15A. Figures 33A to 33C are perspective views, radial cross-sectional views, and axial cross-sectional views showing the oil volume adjustment member 102 located in the first radial oil passage 84, which will be described later. The basic configuration of the first-stage pipe expansion mold 15A described above is denoted by the same reference numerals and its explanation is omitted.

[0090] Figure 27 differs from Figure 8 in the number of outer ring molds 34. In Figure 8, five outer ring molds 34A to 34E were shown fitted to the core mold 32 between the mold base 31 and the first tip mold 33A, but in Figure 27, ten outer ring molds 34 are fitted to the core mold 32. For the sake of explanation, the multiple outer ring molds 34 will not be distinguished by different reference numerals below. Also, the detection device 43 is not shown in Figure 27. In the first embodiment of the tube expansion mold of this disclosure, the outer ring molds 34 are not fixed to the outer surface of the core mold 32, and each of the outer ring molds 34 is provided to be rotatable in the circumferential direction of the tube expansion mold.

[0091] As shown in Figure 27, the mold base 31 of the first-stage expanding mold 15A is provided with an oil inlet 81a and a base flow path 82a that penetrates the mold base 31 radially. The core mold 32 is provided with a first axial oil flow path 83a that connects to the base flow path 82a and penetrates the partial core mold 32A axially, and a first radial oil flow path 84 that connects to the first axial oil flow path 83a, penetrates the partial core mold 32A radially, and extends to the outer circumferential surface of the partial core mold 32A. An oil volume adjustment member 102 is provided in the first radial oil flow path 84. As shown in Figures 28 and 29, the core mold 32 is also provided with a second circumferential oil flow path 85 that connects to the first radial oil flow path 84 and extends in the circumferential direction of the outer circumferential surface of the partial core mold 32A. Furthermore, at the boundary between the two outer ring molds 34, a second radial oil passage 87 is provided, which connects to the first radial oil passage 84 via a second circumferential oil passage 85, penetrates the outer ring mold 34 radially, and extends to the outer surface of the outer ring mold 34. For the sake of explanation, in Figures 27-29, the first radial oil passage 84 and the second radial oil passage 87 are shown to be substantially on the same straight line and connected to each other. On the other hand, as described above, in the first embodiment of the tube expansion mold of this disclosure, the outer ring mold 34 is rotatable in the circumferential direction. When the outer ring mold 34 rotates circumferentially from the position shown in Figures 27-29, and the first radial oil passage 84 and the second radial oil passage 87 are not substantially on the same straight line, the first radial oil passage 84 and the second radial oil passage 87 are positioned offset from each other along the second circumferential oil passage 85. Even in this case, the first radial oil passage 84 and the second radial oil passage 87 are indirectly connected via the second circumferential oil passage 85.

[0092] With the above flow path configuration, the lubricating oil introduced into the first-stage pipe expansion die 15A can reach the outer surface of the outer ring die 34, which comes into contact with the pipe 13 that is the target of the pipe expansion process. Specifically, the lubricating oil introduced from the oil inlet 81a passes through the base flow path 82a and through the inside of the die base 31. The lubricating oil that reaches the inside of the partial core die 32A proceeds axially (direction A in Figure 27) via the first axial oil flow path 83a and radially outward via the first radial oil flow path 84 to the outer surface of the partial core die 32A. The lubricating oil that reaches the outer surface of the partial core die 32A passes through the second circumferential die oil flow path 85 and radially outward via the second radial oil flow path 87 to reach the outer surface of the outer ring die 34.

[0093] As shown in Figures 28, 29, 30A, and 31, a first circumferential oil passage 88 is provided on the outer circumferential surface of the boundary between the two outer ring molds 34, connecting to a second radial oil passage 87 and extending in the circumferential direction. This first circumferential oil passage 88 makes it possible to supply lubricating oil in the circumferential direction of the outer circumferential surface of the outer ring mold 34 that comes into contact with the pipe 13 to be expanded in the first stage pipe expansion mold 15A.

[0094] Furthermore, as described above, in the pipe expansion process using the first-stage pipe expansion die 15A shown in Figures 17-1 and 17-2, the inner circumferential surface of the pipe 13 and the outer circumferential surface of the first-stage pipe expansion die 15A that abuts against it are rubbed against each other along the axial direction. Therefore, the lubricating oil that has passed radially outward through the second radial oil passage 87 and reached the first circumferential oil passage 88 is supplied axially to the outer circumferential surface of the outer ring die 34 in the pipe expansion process using the first-stage pipe expansion die 15A.

[0095] Furthermore, as shown in Figures 28 and 29, in addition to the second circumferential oil passage 85 that is directly connected to the first radial oil passage 84 as described above, a plurality of second circumferential oil passages 85 are provided on the outer circumferential surface of the partial core mold 32A at predetermined intervals along the axial direction. Specifically, a plurality of second circumferential oil passages 85 are provided to match the axial width of the outer ring mold 34. A second axial oil passage 86 is provided that extends axially along the outer circumferential surface of the partial core mold 32A, traversing and connecting the plurality of second circumferential oil passages 85. On the other hand, the boundary portions of each of the plurality of outer ring molds 34 fitted into the partial core mold 32A are provided with the second radial oil passages 87 and the first circumferential oil passages 88 described above. With this configuration, the lubricating oil that reaches the outer circumferential surface of the partial core mold 32A travels axially (directions A and B in Figure 27) via the second axial oil passage 86, passes radially through the outer ring mold 34 via a plurality of second radial oil passages 87 provided at predetermined intervals along the circumferential direction (i.e., at predetermined angular positions on the annule), and reaches the first circumferential oil passage 88 at multiple locations on the outer circumferential surface of the outer ring mold 34. Therefore, in the first stage pipe expansion mold 15A, it is possible to supply lubricating oil in the axial direction (directions A and B in Figure 27) to the outer circumferential surface of the outer ring mold 34 that comes into contact with the pipe 13 that is the target of pipe expansion.

[0096] In the above description, the second circumferential oil passage 85 and the second axial oil passage 86 were formed on the outer circumferential surface of the partial core mold 32A. However, it is also possible to form the second circumferential oil passage 85 and the second axial oil passage 86 on the inner circumferential surfaces of the multiple outer ring molds 34 facing the outer circumferential surface of the partial core mold 32A. Alternatively, it is also possible to form the second circumferential oil passage 85 and the second axial oil passage 86 on both the outer circumferential surface of the partial core mold 32A and the inner circumferential surfaces of the multiple outer ring molds 34.

[0097] Figures 27-29 show that the second axial oil passage 86 is directly connected to the first radial oil passage 84. In other words, the first radial oil passage 84, the second axial oil passage 86, and the second radial oil passage 87 merge with each other in the second circumferential oil passage 85. However, this is not an essential configuration for the first-stage tube expansion mold 15A. The relationship between the oil passages can be changed as long as lubricating oil can be supplied appropriately. Specifically, the first radial oil passage 84 and the second axial oil passage 86 may merge into the second circumferential oil passage 85 at positions offset from each other along the second circumferential oil passage 85, without being directly connected to each other.

[0098] As shown in Figure 30A, the first circumferential oil passage 88 formed on the outer circumferential surface of the boundary between the two outer ring molds 34 is configured to have a V-shaped cross-section as an example. However, the cross-sectional shape of the first circumferential oil passage 88 is not limited to a V-shape; a U-shape, square, or other shape can be selected as long as lubricating oil can be adequately supplied to the outer circumferential surface of the outer ring mold 34.

[0099] As shown in Figure 30B, the second axial oil passage 86, which extends axially from the outer circumferential surface of the partial core mold 32A, is configured to have a rectangular cross-section as an example. However, the cross-sectional shape of the second axial oil passage 86 is not limited to a rectangle; U-shaped, V-shaped, and other shapes can be selected as long as lubricating oil can be adequately supplied to the outer circumferential surface of the partial core mold 32A.

[0100] Each of the oil passages in the first-stage expanding mold 15A can be configured as follows: The base passage 82a can be configured by forming a through hole in the mold base 31 (see Figures 27 and 32). The first axial oil passage 83a and the first radial oil passage 84 can be configured by forming a through hole in the partial core mold 32A (see Figure 27). The second circumferential oil passage 85 and the second axial oil passage 86 can be configured by forming a groove on the outer surface of the partial core mold 32A (see Figure 29).

[0101] On the other hand, the second radial oil passage 87 and the first circumferential oil passage 88, which are provided at the boundary between adjacent outer ring molds 34, can be constructed by forming grooves in the outer ring molds 34. Specifically, as shown in Figure 31, radial grooves corresponding to the second radial oil passage 87 are formed on the side surface of the outer ring mold 34, and circumferential grooves corresponding to the first circumferential oil passage 88 are formed at the outer corners of the outer ring molds 34. By combining outer ring molds 34 having grooves as shown in Figure 31, the second radial oil passage 87 and the first circumferential oil passage 88 are constructed at the boundary between two outer ring molds 34 (see Figure 30A).

[0102] Figure 31 shows six radial grooves formed at equally spaced positions in the circumferential direction on the side surface (orthoaxial surface) of the outer ring mold 34. In this case, the outer ring mold 34 is provided with six second radial oil passages 87. However, the number and spacing of the second radial oil passages 87 are not limited to this, and the number and spacing can be changed as long as lubricating oil can be adequately supplied to the outer surface of the outer ring mold 34.

[0103] The above describes a single flow path system (hereinafter referred to as the first flow path system) formed in the first-stage expanding mold 15A, which includes a first axial oil flow path 83a that penetrates the partial core mold 32A. However, the flow path systems formed in the first-stage expanding mold 15A are not limited to the first flow path system, and it is possible to provide multiple flow path systems in the first-stage expanding mold 15A. As an example, Figure 27 shows a second flow path system which includes another first axial oil flow path 83b that connects to another oil inlet section 81b via another base flow path 82b (different from the base flow path 82a) of the mold base 31, and extends into the interior of the partial core mold 32B by penetrating the partial core mold 32A. Although not shown in the diagram and details, this second flow path system, like the first flow path system, includes a first radial oil flow path 84 provided inside the partial core mold 32B, a second circumferential oil flow path 85 and a second axial oil flow path 86 provided on the outer circumferential surface of the partial core mold 32B, and a second radial oil flow path 87 and a first circumferential oil flow path 88 provided at the boundary between adjacent outer ring molds 34. The second flow path system makes it possible to supply lubricating oil introduced from the oil inlet 81b provided on the mold base 31 in the circumferential and axial directions (directions A and B in Figure 27) of the outer circumferential surface of the outer ring mold 34. By providing the second flow path system in addition to the first flow path system, the oil volume and pressure of each flow path system can be controlled separately, and the oil volume and hydraulic pressure suitable for pipe expansion can be adjusted.

[0104] Furthermore, it is also possible to provide a flow path system for directly supplying lubricating oil to the outer surface of the first tip mold 33A, rather than to the outer ring mold 34 fitted to the core mold 32. As an example, Figure 27 shows a third flow path system, which includes a first axial oil flow path 83c that penetrates the partial core molds 32A and 32B and extends into the interior of the first tip mold 33A. In the first stage expanding mold 15A shown in Figure 27, unlike in Figure 8, the outer periphery of the first tip mold 33A adjacent to the partial core mold 32B is composed of a set of adjacent tip outer ring molds 36. Although not shown in detail, the tip outer ring mold 36, like the outer ring mold 34 shown in Figure 31, is provided with a groove extending radially on its side (corresponding to a second radial oil flow path 87) and a groove extending circumferentially at its corner (corresponding to a first circumferential oil flow path 88). As shown in Figure 27, a first radial oil passage 84 connected to a first axial oil passage 83c is provided inside the first tip mold 33A. Furthermore, although not shown in the illustration and detailed description, a second circumferential oil passage 85 and a second axial oil passage 86 are provided in the first tip mold 33A at the location facing the inner circumferential surface of the tip outer ring mold 36, similar to the partial core mold 32A shown in Figures 27-29. In other words, the third flow path system, similar to the first and second flow path systems, includes a first radial oil passage 84 provided inside the first tip mold 33A, a second circumferential oil passage 85 and a second axial oil passage 86 provided at the location facing the inner circumferential surface of the tip outer ring mold 36, and a second radial oil passage 87 and a first circumferential oil passage 88 provided at the boundary between adjacent tip outer ring molds 36. The third flow path system makes it possible to supply lubricating oil, which is introduced from the oil inlet section 81c (see Figure 32) provided in the mold base 31, to the outer surface of the first tip mold 33A in the circumferential and axial directions (directions A and B in Figure 27).

[0105] Figure 32 is a view of the mold base 31 of the first-stage pipe expansion mold 15A from direction B in Figure 27, showing the oil inlet 81a connected to the base flow path 82a of the first flow path system, the oil inlet 81b connected to the base flow path 82b of the second flow path system, and the oil inlet 81c connected to the first axial oil flow path 83c of the third flow path system. By introducing pressurized lubricating oil into the oil inlet 81a to 81c using a pump (not shown), the lubricating oil travels through the first to third flow path systems and is supplied to the outer surfaces of the outer ring mold 34 and the tip outer ring mold 36. By appropriately pressurizing each of the oil inlet 81a to 81c, the amount and pressure of the lubricating oil supplied between the pipe 13 and the first-stage pipe expansion mold 15A can be adjusted. It is possible to supply lubricating oil in an appropriate amount and hydraulic pressure according to the friction between the pipe 13 and the first-stage pipe expansion mold 15A.

[0106] In the above description, it was assumed that the first-stage pipe expansion die 15A is provided with first to third flow path systems, but the number of flow path systems can be changed to a number suitable for pipe expansion, such as 1, 2, or 4. Furthermore, the configuration of the oil flow path can be changed in each flow path system. For example, in a certain flow path system, it is possible to omit one or both of the second circumferential oil flow path 85 and the second axial oil flow path 86.

[0107] Figures 33A to 33C show an example of an oil volume adjustment member 102 provided in the first radial oil passage 84. The oil volume adjustment member 102 has a through hole 102A. By changing the diameter φA of the through hole 102A, the flow rate of lubricating oil flowing from the first radial oil passage 84 to the outer surface of the core mold 32 can be adjusted, making it possible to supply an appropriate amount of lubricating oil in each flow path system.

[0108] In the above description, it was assumed that each of the first to third flow path systems is provided with a single combination of a first radial oil flow path 84 and an oil volume adjustment member 102. However, the number of combinations of first radial oil flow paths 84 and oil volume adjustment members 102 in a single flow path system is not limited to one; it is also possible to provide multiple combinations of first radial oil flow paths 84 and oil volume adjustment members 102 in a single flow path system.

[0109] Furthermore, in the above description, the outer ring molds 34 are not fixed to the outer surface of the core mold 32, and each of the outer ring molds 34 is provided to be rotatable in the circumferential direction of the tube expansion mold. However, it is also possible to fix the outer ring molds 34 to the outer surface of the core mold 32 and position them so that they do not rotate in the circumferential direction. In particular, as shown in Figures 27 to 29, if the first radial oil passage 84 and the second radial oil passage 87 are substantially on the same straight line, and the outer ring molds 34 do not rotate in the circumferential direction from this position, then even without providing the second circumferential oil passage 85, the lubricating oil that has reached the outer surface of the partial core mold 32A via the first radial oil passage 84 can flow into the second radial oil passage 87. In this sense, in the first embodiment of the tube expansion mold of this disclosure, the second circumferential oil passage 85 is not an essential component.

[0110] The oil passage provided in the first-stage pipe-expanding die 15A (Figure 8, the first embodiment of the pipe-expanding die of this disclosure) has been described above. Similarly, oil passage systems can be provided in the second-stage pipe-expanding die 15B (Figure 9, the second embodiment) and the third-stage pipe-expanding die 15C (Figure 10, the third embodiment). By appropriately providing flow system systems in each of the first-stage pipe-expanding die 15A, the second-stage pipe-expanding die 15B, and the third-stage pipe-expanding die 15C, frictional resistance generated between the pipe 13 and the pipe-expanding die 15 during the pipe-expanding process shown in Figures 17 to 20 can be suppressed, and seizure between the pipe 13 and the pipe-expanding die 15 can be prevented. Furthermore, by suppressing frictional resistance, the force required for pipe-expanding can be reduced.

[0111] (2-2. Oil passages provided in the pipe shrinking mold) Next, the oil passages provided in the pipe shrinkage mold according to this disclosure will be described. Figure 34 is a cross-sectional view of the first stage pipe shrinkage mold 21A (a first embodiment of the pipe shrinkage mold according to this disclosure), corresponding to Figure 13, in a pipe shrinkage mold to which the oil passages are applied. Figure 35 is a perspective view of the first stage pipe shrinkage mold 21A cut to show its external appearance, corresponding to Figure 12. Figure 36 is a perspective view of the inner circumferential surface of the outer cylindrical mold 61, obtained by rotating the first stage pipe shrinkage mold 21A shown in Figure 35 by 90 degrees around its central axis and removing a part of the inner circumferential ring mold 63. Figure 37 is an enlarged view of the main part of the passage configuration in Figure 36. Figure 38A is an enlarged cross-sectional view taken along the arrow 38A-38A in Figure 34. Figure 38B is a cross-sectional view taken along the arrow 38B-38B in Figure 37. Figure 39 is a perspective view of the inner circumferential ring mold 63 of the first stage pipe shrinkage mold 21A, corresponding to Figure 16. Figures 40A to 40C are perspective and cross-sectional views showing the oil volume adjustment member 106 located in the 11th axial oil passage 92, which will be described later. The basic configuration of the first-stage pipe reduction mold 21A described above is denoted by the same reference numerals and its explanation is omitted.

[0112] Figure 34 differs from Figure 13 in the number of inner ring molds 63. In Figure 13, four inner ring molds 63A to 63D were shown inserted and fitted into the outer cylindrical mold 61 between the mold base 31 and the first tip mold 62A, but in Figure 34, seven inner ring molds 63 are inserted and fitted into the outer cylindrical mold 61. For the sake of clarity, the multiple inner ring molds 63 will not be distinguished by different reference numerals below. Also, the detection device 43 is not shown in Figure 34. In the first embodiment of the tube shrinking mold of this disclosure, the inner ring molds 63 are not fixed to the inner surface of the outer cylindrical mold 61, and each of the inner ring molds 63 is provided so as to be rotatable in the circumferential direction of the tube shrinking mold. For the sake of clarity, the following description of the oil passages will use ordinal numbers starting from "11th," such as "11th axial oil passage 92a" and "12th axial oil passage 99a."

[0113] As shown in Figure 34, the first tip mold 62A of the first stage retraction mold 21A is provided with an oil inlet 91a and a 12th axial oil passage 99a that penetrates the first tip mold 62A in the axial direction. The outer cylindrical mold 61 of the first stage retraction mold 21A is provided with an 11th axial oil passage 92a that communicates with the 12th axial oil passage 99a and penetrates the partial outer cylindrical mold 61B in the axial direction and enters the interior of the partial outer cylindrical mold 61A. An oil volume adjustment member 106 is provided in the 11th axial oil passage 92a. The partial outer cylindrical mold 61A is also provided with an 11th radial oil passage 93 that connects to the 11th axial oil passage 92a and penetrates the partial outer cylindrical mold 61A radially and extends to the inner surface of the partial outer cylindrical mold 61A.

[0114] Here, we will explain Figures 36 and 37 in detail. Figure 36 shows the first-stage tube reduction mold 21A shown in Figure 35 rotated 90 degrees around its central axis, and the third and fourth inner circumferential ring molds 63 from the right among the seven inner circumferential ring molds 63 shown in Figure 35 have been removed. As a result of removing a portion of the inner circumferential ring molds 63, Figure 36 shows the inner surface of the partial outer circumferential cylindrical mold 61A that abuts against the outer surface of the third inner circumferential ring mold 63 from the right in Figure 35 (hatched portion). Figure 37 is an enlarged view of the main part of Figure 36. As shown in Figures 36 and 37, a twelfth circumferential oil passage 94 is provided at the location on the inner surface of the partial outer circumferential cylindrical mold 61A that is in contact with the boundary of the inner circumferential ring mold 63, and is connected to the eleventh radial oil passage 93 and extends in the circumferential direction of the partial outer circumferential cylindrical mold 61A.

[0115] As shown in Figures 34, 35, and 39, a 12th radial oil passage 95 is provided at the boundary (orthogonal plane) of the two inner ring molds 63, connected to the 11th radial oil passage 93, and extending radially through the inner ring mold 63 to the inner surface of the inner ring mold 63. For the sake of explanation, in Figures 34 and 35, the 11th radial oil passage 93 and the 12th radial oil passage 95 are shown to be substantially on the same straight line and connected to each other. On the other hand, as described above, in the first embodiment of the tube shrinkage mold of this disclosure, the inner ring mold 63 is rotatable in the circumferential direction. When the inner ring mold 63 rotates circumferentially from the position shown in Figures 34 and 35, and the 11th radial oil passage 93 and the 12th radial oil passage 95 are not substantially on the same straight line, the 11th radial oil passage 93 and the 12th radial oil passage 95 are positioned offset from each other along the 12th circumferential oil passage 94. Even in this case, the 11th radial oil passage 93 and the 12th radial oil passage 95 are indirectly connected via the 12th circumferential oil passage 94.

[0116] With the above flow path configuration, the lubricating oil introduced into the first-stage pipe shrinking mold 21A can reach the inner surface of the inner ring mold 63, which comes into contact with the pipe 13 that is the target of the pipe shrinking process. Specifically, the lubricating oil introduced from the oil inlet section 91a passes through the interior of the first tip mold 62A via the 12th axial oil flow path 99a. The lubricating oil that reaches the interior of the outer cylindrical mold 61 proceeds axially (direction B in Figure 34) via the 11th axial oil flow path 92a, and radially inward via the 11th radial oil flow path 93, to the inner surface of the partial outer cylindrical mold 61A. The lubricating oil that reaches the inner surface of the partial outer cylindrical mold 61A passes through the 12th circumferential oil flow path 94 and radially inward via the 12th radial oil flow path 95, reaching the inner surface of the inner ring mold 63.

[0117] As shown in Figures 35-37, 38A, and 39, the inner surface of the boundary between the two inner ring molds 63 is provided with an eleventh circumferential oil passage 96 that extends circumferentially and is connected to a twelfth radial oil passage 95. Therefore, in the first stage pipe shrinkage mold 21A, it is possible to supply lubricating oil in the circumferential direction of the inner surface of the inner ring mold 63 that comes into contact with the pipe 13 to be shrunk.

[0118] Furthermore, as described above, in the pipe shrinking process using the first-stage pipe shrinking die 21A shown in Figures 22-1 and 22-2, the outer surface of the pipe 13 and the inner surface of the first-stage pipe shrinking die 21A that is in contact with it are rubbed against each other along the axial direction. Therefore, the lubricating oil that has passed radially inward through the 12th radial oil passage 95 and reached the 11th circumferential oil passage 96 is supplied axially to the inner surface of the inner ring die 63 in the pipe expansion process using the first-stage pipe shrinking die 21A.

[0119] As shown in Figures 34-37, in addition to the 12th circumferential oil passage 94 that is directly connected to the 11th radial oil passage 93 as described above, multiple 12th circumferential oil passages 94 are provided on the inner circumferential surfaces of the partial outer cylindrical mold 61A and the partial outer cylindrical mold 61B at predetermined intervals along the axial direction. Specifically, multiple 12th circumferential oil passages 94 are provided so as to match the axial width of the inner ring mold 63 and so as to face the boundary of adjacent inner ring molds 63. A 13th axial oil passage 97 is provided that extends axially along the inner circumferential surface of the partial outer cylindrical mold 61A, connecting and traversing the multiple 12th circumferential oil passages 94. As described above, in Figures 36 and 37, a part of the inner ring mold 63 has been removed, so a part of the 13th axial oil passage 97 is exposed. Figure 38B shows a cross-section of the 13th axial oil passage 97. On the other hand, the boundary portions (planes perpendicular to the axis) of each of the multiple inner ring molds 63 inserted and fitted into the partial outer cylindrical mold 61A are provided with the aforementioned 12th radial oil passage 95 and 11th circumferential oil passage 96 (see Figures 38A and 39). With this configuration, the lubricating oil that reaches the inner surface of the partial outer cylindrical mold 61A travels axially (directions A and B in Figure 34) via the 13th axial oil passage 97, passes radially inward through the multiple second radial oil passages 95 provided at predetermined intervals along the circumferential direction (i.e., at predetermined angular positions of the annule), and reaches the multiple 11th circumferential oil passages 96 on the inner surface of the inner ring mold 63. Thus, in the first stage pipe shrinking mold 21A, it is possible to supply lubricating oil in the axial direction (directions A and B in Figure 34) of the inner surface of the inner ring mold 63 that is in contact with the pipe 13 that is the target of pipe shrinking.

[0120] In the above description, the 12th circumferential oil passage 94 and the 13th axial oil passage 97 were described as being formed on the inner circumferential surface of the outer cylindrical mold 61. However, it is also possible to form the 12th circumferential oil passage 94 and the 13th axial oil passage 97 on the outer circumferential surface of the inner ring mold 63, which is opposite the inner circumferential surface of the outer cylindrical mold 61. Furthermore, it is also possible to form the 12th circumferential oil passage 94 and the 13th axial oil passage 97 on both the outer circumferential surface of the inner ring mold 63 and the inner circumferential surface of the outer cylindrical mold 61.

[0121] Figures 34-37 show that the 13th axial oil passage 97 is directly connected to the 11th radial oil passage 93 and the 12th radial oil passage 95. In other words, the 11th radial oil passage 93, the 13th axial oil passage 97, and the 12th radial oil passage 95 merge with each other in the 12th circumferential oil passage 94. However, this is not an essential configuration for the first-stage pipe-reducing mold 21A. The relationship between the oil passages can be changed as long as lubricating oil can be supplied appropriately. For example, the 11th radial oil passage 93 and the 13th axial oil passage 97 may not be directly connected to each other, but may merge with the 12th circumferential oil passage 94 at positions offset from each other along the 12th circumferential oil passage 94.

[0122] As shown in Figure 38A, the 11th circumferential oil passage 96 formed on the inner surface of the boundary between adjacent inner ring molds 63 is configured to have an inverted V-shaped cross-section as an example. However, the cross-sectional shape of the 11th circumferential oil passage 96 is not limited to an inverted V-shape; an inverted U-shape, a square, and other shapes can be selected as long as lubricating oil can be adequately supplied to the outer surface of the outer ring mold 34.

[0123] As shown in Figure 38B, the 13th axial oil passage 97, which extends axially along the inner surface of the partial outer cylindrical mold 61A (and the outer surface of the inner ring mold 63 opposite it), is configured to have a rectangular cross-section as an example. However, the cross-sectional shape of the 13th axial oil passage 97 is not limited to a rectangle; U-shaped, V-shaped, and other shapes can be selected as long as lubricating oil can be adequately supplied to the inner surface of the partial outer cylindrical mold 61A.

[0124] Each of the oil passages in the first-stage retraction mold 21A can be configured as follows: The twelfth axial oil passage 99a can be configured by forming a through hole in the first tip mold 62A. The eleventh axial oil passage 92a can be configured by forming a through hole in the axial direction of the partial outer cylindrical molds 61B and 61A. The eleventh radial oil passage 93 can be configured by forming a through hole in the radial direction of the partial outer cylindrical mold 61A.

[0125] On the other hand, the 12th radial oil passage 95 and the 11th circumferential oil passage 96, which are provided at the boundary between adjacent inner ring molds 63, can be constructed by forming grooves in the inner ring molds 63. Specifically, as shown in Figure 39, radial grooves corresponding to the 12th radial oil passage 95 are formed on the side surface of the inner ring mold 63, and circumferential grooves corresponding to the 11th circumferential oil passage 96 are formed at the inner corners of the inner ring molds 63. By combining inner ring molds 63 having grooves as shown in Figure 39, the 12th radial oil passage 95 and the 11th circumferential oil passage 96 are constructed at the boundary between two inner ring molds 63 (see Figure 38A).

[0126] Figure 39 shows six radial grooves formed at equally spaced positions in the circumferential direction on the side surface (orthogonal plane) of the inner ring mold 63. In this case, the inner ring mold 63, which is inserted and fitted into the partially outer cylindrical mold 61A, is provided with six 12th radial oil passages 95. However, the number and spacing of the 12th radial oil passages 95 are not limited to this, and the number and spacing can be changed as long as lubricating oil can be adequately supplied to the inner surface of the inner ring mold 63.

[0127] The above describes a single flow path system (hereinafter referred to as the first flow path system) formed in the first-stage retractable mold 21A, which includes an 11th axial oil flow path 92a that penetrates the partial outer cylindrical mold 61B and enters the partial outer cylindrical mold 61A. However, the flow path systems formed in the first-stage retractable mold 21A are not limited to the first flow path system, and it is possible to provide multiple flow path systems in the first-stage retractable mold 21A. As an example, Figure 34 shows a second flow path system which includes another 11th axial oil flow path 92b that connects to another oil inlet section 91b via another 12th axial oil flow path 99b and penetrates the partial outer cylindrical mold 61B but does not extend into the interior of the partial outer cylindrical mold 61A. Although not shown in the diagram and details, this second flow path system, like the first flow path system, includes a 12th circumferential oil flow path 94 and a 13th axial oil flow path 97 provided on the inner surface of the partial outer cylindrical mold 61B (and the outer surface of the inner ring mold 63 facing it), and a 12th radial oil flow path 95 and an 11th circumferential oil flow path 96 provided at the boundary between adjacent inner ring molds 63. The second flow path system makes it possible to supply lubricating oil introduced from the oil input section 91b provided in the first tip mold 62A in the circumferential and axial directions (directions A and B in Figure 34) of the inner surface of the inner ring mold 63.

[0128] Figures 34 and 35 show a pipe 105a connected to an oil inlet 91a connected to the 12th axial oil passage 99a of the first flow path system, and a pipe 105b connected to an oil inlet 91b connected to the 12th axial oil passage 99b of the second flow path system. By introducing pressurized lubricating oil to the oil inlet 91a and 91b via pipes 105a and 105b using a pump (not shown), the lubricating oil travels through the first and second flow path systems and is supplied to the inner surface of the inner ring mold 63. By appropriately pressurizing each of the oil inlet 91a and 91b, the amount and pressure of lubricating oil supplied between pipe 13 and the first-stage retraction mold 21A can be adjusted. It is possible to supply lubricating oil in an appropriate amount and in an appropriate manner depending on the friction between pipe 13 and the first-stage retraction mold 21A. By providing a second flow path system in addition to the first flow path system, the oil volume and pressure of each flow path system can be controlled separately, allowing for adjustment of the oil volume and hydraulic pressure suitable for pipe shrinking.

[0129] In the above description, it was assumed that the first stage pipe reduction die 21A is provided with first and second flow path systems, but the number of flow path systems can be changed to a number suitable for pipe reduction processing, such as 1, 3, or 4. Furthermore, the configuration of the oil flow path can be changed in each flow path system. For example, in a certain flow path system, it is possible to omit one or both of the 12th circumferential oil flow path 94 and the 13th axial oil flow path 97.

[0130] Figure 40A is a perspective view showing an example of an oil volume adjustment member 106 provided in the 11th axial oil passage 92. Figures 40B and 40C are cross-sectional views showing the operation of the oil volume adjustment member 106. As shown in Figure 40A, the oil volume adjustment member 106 comprises a main body portion 106A, a gripping portion 106B, and a tip portion 106C. The surface of the main body portion 106A of the oil volume adjustment member 106 is threaded. As shown in Figures 34 and 35, the main body portion 106A of the oil volume adjustment member 106 is inserted into a threaded hole formed in the partial outer cylindrical mold 61A. By gripping and rotating the gripping portion 106B, the oil volume adjustment member 106 can be moved radially in the partial outer cylindrical mold 61A.

[0131] Figures 40B and 40C show the relative arrangement of the tip portion 106C of the oil volume adjustment member 106 and the 11th radial oil passage 93 formed in the partially outer cylindrical mold 61A. Lubricating oil flowing in from the 11th axial oil passage 92a flows into the 11th radial oil passage 93 while colliding with the tip portion 106C of the oil volume adjustment member 106. Compared to the arrangement shown in Figure 40B, in Figure 40C, the tip portion 106C of the oil volume adjustment member 106 blocks the entrance to the 11th radial oil passage 93, thus suppressing the flow rate and oil pressure of the lubricating oil flowing into the 11th radial oil passage 93. By gripping and rotating the gripping portion 106B of the oil volume adjustment member 106, the radial arrangement of the tip portion 106C of the oil volume adjustment member 106 can be adjusted to obtain the desired flow rate and oil pressure.

[0132] In the above description, it was assumed that each of the first and second flow path systems is provided with a single combination of an 11th radial oil flow path 93 and an oil volume adjustment member 106. However, the number of combinations of an 11th radial oil flow path 93 and an oil volume adjustment member 106 in a single flow path system is not limited to one; it is also possible to provide multiple combinations of an 11th radial oil flow path 93 and an oil volume adjustment member 106 in a single flow path system.

[0133] In the first-stage retraction mold 21A shown in Figures 34 to 37, the oil inlet 91 was located on the tip mold 62. However, the placement of the oil inlet 91 is not limited to this, and it may be located on either the mold base 31A or the outer cylindrical molds 61A or 61B. Although not shown in the illustrations and detailed explanation, in this case, the path to reach the 11th radial oil passage 93 (i.e., the 12th axial oil passage 99a and the 11th axial oil passage 92a) is appropriately changed according to the placement of the oil inlet 91.

[0134] Furthermore, in the above description, the inner circumferential ring mold 63 is not fixed to the inner circumferential surface of the outer cylindrical mold 61, and each of the inner circumferential ring molds 63 is provided to be rotatable in the circumferential direction of the pipe-reducing mold. However, it is also possible to fix the inner circumferential ring mold 63 to the inner circumferential surface of the outer cylindrical mold 61 and position it so that it does not rotate in the circumferential direction. In particular, as shown in Figures 34 and 35, if the 11th radial oil passage 93 and the 12th radial oil passage 95 are substantially on the same straight line, and the inner circumferential ring mold 63 does not rotate in the circumferential direction from this arrangement, then even without providing the 12th circumferential oil passage 94, the lubricating oil that has reached the inner circumferential surface of the partial outer cylindrical mold 61A via the 11th radial oil passage 93 can flow into the 12th radial oil passage 95. In this sense, in the first embodiment of the pipe-reducing mold of this disclosure, the 12th circumferential oil passage 94 is not an essential component.

[0135] The oil passage provided in the first-stage pipe shrinkage die 21A (Figure 13, the first embodiment of the pipe shrinkage die of this disclosure) has been described above. Similarly, oil passage systems can be provided in the second-stage pipe shrinkage die 21B (Figure 14, the second embodiment) and the third-stage pipe shrinkage die 21C (Figure 15, the third embodiment). By appropriately providing flow system systems in each of the first-stage pipe shrinkage die 21A, the second-stage pipe shrinkage die 21B, and the third-stage pipe shrinkage die 21C, frictional resistance generated between the pipe 13 and the pipe shrinkage die 21 during the pipe shrinkage process shown in Figures 22 to 25 can be suppressed, and seizure between the pipe 13 and the pipe shrinkage die 21 can be prevented. Furthermore, by suppressing frictional resistance, the force required for pipe shrinkage can be reduced. [Explanation of Symbols]

[0136] 1. Pipe expansion or reduction processing device 2 Steel pipe processing department 3. Delivery Table 4. Loading table 5 frames 6, 8, 23 Hydraulic Cylinders 6a, 8a Cylinder rod 7, 9, 22 Mounting frame 10 clamps 10A, 10B clamp arm 11 Extension shaft 12 Pressing shaft 13 Steel pipe 14 Feed rollers 15 (15A~15C) Tube expansion mold 16 (16A~16C) Release ring 16a Through hole 17. Mold mounting substrate 21 (21A~21C) Pipe shrinkage mold 24 Cylinder rod 26 Restraining Rod 26a Nut 27 Press Plate 28 Laura followers 31, 31A Mold base 32(32A, 32B) Core mold 33 (33A~33C), 62 (62A~62C) Advanced mold 33a, 33b, 33c, 34a, 51a, 53a, 62a, 62b, 62c, 63a, 78a, 79a Tapered section 33a1, 33b1, 62a1, 62b1 Guide section Outer ring molds for 34 (34A~34D), 51 (51A~51D), and 53 (53A~53D) 35, 52, 54 Color 36-38, 41, 65-67, 72, 77A-77C bolts 40 Contact pins 42 Guide Rod 43 Detection device 44 sensors 45 Dog 61 (61A, 61B) Outer cylindrical mold 63 (63A~63D), 78 (78A~78D), 79 (79A~79D) Inner Circumference Ring Mold 71 Fixed Cylinder 73 Release pressing member 74 Base plate 74a Keyway 75 Intermediate ring 76 (76A~76C) Pressure Plate 78 keys 81a… Oil Input Department 81b…Oil Input Department 81c… Oil Input Department 82a…Buse flow path 82b…ベース flow path 83a… Oil flow path in the first axis direction 83b… Oil flow path in the first axis direction 83c… Oil flow path in the first axis direction 84… Oil flow path in the first radial direction 85… Week 2 Directional Oil Flow Path 86… Oil flow path in the second axis direction 87… Oil flow path in the second radial direction 88… Week 1 Directional Oil Flow Path 91a… Oil Input Department 91b… Oil Input Department 92… Oil flow path in the 11th axis direction 92a… Oil flow path in the 11th axis direction 92b… Oil flow path in the 11th axis direction 93…11th radial direction oil flow path 94… 12th week directional oil flow path 95…12th radial direction oil flow path 96… Week 11 Directional Oil Flow Path 97… Oil flow path in the 13th axis direction 99a… Oil flow path in the 12th axis direction 99b… Oil flow path in the 12th axis direction 102… Oil quantity adjustment parts 102A…Through Hole 105a…パイプ 105b…パイプ 106… Oil Quantity Adjustment Parts 106A…Main body part 106B…Control Section 106C…aperture

Claims

1. A pipe expansion die for processing a pipe (13) to enlarge its diameter, The core member (32) extends in the axial direction and comprises a first axial oil passage (83) that is directly or indirectly connected to the oil inlet (81), and a first radial oil passage (84) that is connected to the first axial oil passage (83) and extends to the outer circumferential surface, An outer ring mold (34, 51, 53) is fitted onto the outer circumference of the core member (32), has an outer tapered portion (34a, 51a, 53a) at one end, and includes a second radial oil passage (87) that is directly or indirectly connected to the first radial oil passage (84) and extends to the outer surface, and a first circumferential oil passage (88) provided on the outer surface and connected to the second radial oil passage (87), Equipped with, When the inner diameter portion of the tube (13) is pressed in the pressing direction against at least the outer tapered portion (34a, 51a, 53a) of the outer ring mold (34, 51, 53), the tube diameter of the tube (13) is enlarged. The space between the inner diameter portion of the pipe (13) and at least a part of the outer ring mold (34, 51, 53) is lubricated by oil from the first circumferential oil passage (88). At least one of the outer circumferential surface of the core member (32) or the inner circumferential surface of the outer ring mold is provided with a second circumferential oil passage (85) that is directly or indirectly connected to the first radial oil passage (84). Tube expansion mold.

2. The tube expansion mold according to claim 1, A second axial oil passage (86) is provided on at least one of the outer circumferential surface of the core member (32) or the inner circumferential surface of the outer ring mold, and is connected to at least one of the first radial oil passage (84) or the second circumferential oil passage (85). Tube expansion mold.

3. The tube expansion mold according to claim 2, The second circumferential oil passage (85) is provided in multiple locations along the axial direction of the pipe expansion mold. The second axial oil passage (86) crosses the plurality of second circumferential oil passages (85) while connecting them. Tube expansion mold.

4. A tube expansion mold according to any one of claims 1 to 3, The outer peripheral ring mold (34, 51, 53) is composed of a plurality of partial outer peripheral ring molds (34, 51, 53) stacked in the axial direction. Tube expansion mold.

5. The tube expansion mold according to claim 4, The second radial oil passage (87) is provided in each of the plurality of partial outer ring molds (34, 51, 53), Each of the multiple partial outer ring molds (34, 51, 53) is provided with a plurality of first circumferential oil passages (88) connected to the corresponding second radial oil passages (87). Tube expansion mold.

6. A tube expansion mold according to any one of claims 1 to 5, An oil volume adjustment member (102) is provided in the first radial oil passage (84). Tube expansion mold.

7. A tube expansion mold according to any one of claims 1 to 6, Multiple flow path systems are provided, including the oil inlet section (81), the first axial oil flow path (83), and the first radial oil flow path (84). Tube expansion mold.

8. A pipe reduction die for processing a pipe (13) to reduce its diameter, An outer cylindrical member (61) extending in the axial direction, comprising an 11th axial oil passage (92) connected to an oil inlet (91), and an 11th radial oil passage (93) connected to the 11th axial oil passage (92) and extending to the inner circumferential surface, An inner circumferential ring mold (63, 78, 79) having an inner circumferential tapered portion (63a, 78a, 79a) at one end, a 12th radial oil passage (95) connected to the 11th radial oil passage (93) and extending to the inner circumferential surface, and a 11th circumferential oil passage (96) provided on the inner circumferential surface and connected to the 12th radial oil passage (95), Equipped with, When the outer diameter portion of the tube (13) is pressed in the pressing direction against at least the inner tapered portion (63a, 78a, 79a) of the inner ring mold (63, 78, 79), the tube diameter of the tube (13) is reduced. The space between the outer diameter portion of the pipe (13) and at least a part of the inner circumferential ring mold (63, 78, 79) is lubricated by oil from the 11th circumferential oil passage (96). Pipe shrinkage mold.

9. A pipe shrinking mold according to claim 8, At least one of the inner surface of the outer cylindrical member (61) or the outer surface of the inner ring mold is provided with a 12th circumferential oil passage (94) connected to the 11th radial oil passage (93). Pipe shrinkage mold.

10. A pipe shrinking mold according to claim 9, A thirteenth axial oil passage (97) is provided on at least one of the inner circumferential surface of the outer cylindrical member (61) or the outer circumferential surface of the inner ring mold, and is connected to at least one of the eleventh radial oil passage (93) or the twelfth circumferential oil passage (94). Pipe shrinkage mold.

11. A pipe shrinking mold according to claim 10, The 12th circumferential oil passage (94) is provided in multiple locations along the axial direction of the pipe expansion mold. The 13th axial oil passage (97) crosses the plurality of 12th circumferential oil passages (85) while connecting them. Pipe shrinkage mold.

12. A pipe shrinking mold according to any one of claims 8 to 11, The aforementioned inner circumferential ring mold (63, 78, 79) is composed of a plurality of partial inner circumferential ring molds (63, 78, 79) stacked in the axial direction. Pipe shrinkage mold.

13. A pipe shrinking mold according to claim 12, The 12th radial oil passage (95) is provided in each of the plurality of partial inner circumferential ring molds (63, 78, 79), Multiple 11th circumferential oil passages (96) are provided, each of the multiple partial inner circumferential ring molds (63, 78, 79) and is connected to a corresponding 12th radial oil passage (95). Pipe shrinkage mold.

14. A pipe shrinking mold according to any one of claims 8 to 13, An oil volume adjustment member (106) is provided in the 11th radial oil passage (93). Pipe shrinkage mold.

15. A pipe shrinking mold according to any one of claims 8 to 14, Multiple flow path systems are provided, including the oil inlet section (91), the 11th axial oil flow path (92), the 11th radial oil flow path (93), and the 12th radial oil flow path (95). Pipe shrinkage mold.

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