JP2017087220A - Pipe bending type unit and pipe bending processing device provided with the unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipe bending type unit capable of appropriately performing bending processing for a pipe without being anxious for generation of wrinkles and to provide a pipe bending processing device which is provided with the unit and facilitates retooling.SOLUTION: A pipe bending type unit includes: a holding member 10 which has a first groove part 11 with a hemi-cyclic cross-section on an outer circumferential surface and has a fitted concave part 12 extended by a first prescribed distance to the circumferential direction in a plane vertical to a rotation shaft (A); a pressure-opposing member 20 which has a second groove part 21 with a hemi-cyclic cross-section on an outer circumferential surface and has a fitting projection part 22 extended by a second prescribed distance to the circumferential direction from a tip part thereof; a hollow shaft member (sleeve 70) which supports the holding member and the pressure-opposing member rotatably; and a fixing shaft member (stud 60) stored in the hollow shaft member. The fitting projection part is fitted to the fitted concave part, a pipe receiving groove with a hemi-cyclic cross-section is formed and the pressure-opposing member and the holding member are connected by a hinge bonding via the hollow shaft member.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a pipe bending die unit suitable for pipe bending and a pipe bending apparatus provided with the unit.

  Various bending processes such as press bending, compression bending, tension bending, and pulling are known as bending processes for pipes, but the rotary pulling bending process is most frequently used. In general rotary pulling bending, a pipe is gripped by a gripping mold against a bending mold having a groove on the outer peripheral surface, and the bending mold (and the gripping mold) is pressed while pressing the pipe in the direction of the bending mold by a pressure mold. When rotated, the pipe moves in the tangential direction and is bent along the groove of the bending die, which is described, for example, in the second column of Patent Document 1, and Patent Document 2 also includes paragraphs [0003] to [0003]. [0006] (the bending mold is described as a roll mold).

  In Patent Document 2, regarding a wiper (shoe) provided to prevent wrinkles generated inside a bent portion of a pipe, a wiper that can cope with wear or chipping caused by sliding has been proposed (Patent Document 2). Paragraphs [0013] and [0014]). Similarly, Patent Document 3 states that “a step does not occur between the wiper and the bending die, there is no problem even if pipes of various materials are used, and there is no problem, and the life is extremely long. The purpose is to provide a pipe bending apparatus that does not require frequent equipment adjustment operations, and "a bending die whose outer peripheral surface is formed in an arc shape with a predetermined curvature for bending a pipe, and the bending A pipe bending apparatus comprising: a clamp member that clamps a pipe with a die; and a wiper that rotates the clamp member around the bending die to prevent wrinkles when bending the pipe. The pipe bending apparatus is characterized in that the tip of the wiper in the rotation direction of the clamp member is extended along the curvature of the outer peripheral surface of the bending die beyond the bending start point of the pipe. Are plan (described in paragraph of Patent Document 3 [0005] and [0006]).

  Furthermore, Patent Document 4 relates to a method and an apparatus for “changing die sets quickly and accurately for bending pipes of different dimensions or for different types of pipe bending operations”. A pre-assembled die set is provided and includes a bending die, a clamping die and a pressure die and attachable to a spindle of a tube bending table, wherein the pressure die and the clamping die are releasably connected to the bending die. And a first means for connecting to each other and the bending die in a predetermined alignment relationship, and an operating means for engaging the die set and simultaneously lifting the die including these die sets from the table. (Described on page 7 of Patent Document 4). And “Many tube bending operations require the use of a wiper die and a mandrel, but if necessary, these also form part of a pre-assembled die set”. 8), a mode in which the wiper die is coupled to the bending die by the wiper die arm is also disclosed (page 15 and FIG. 6).

US Pat. No. 5,337,590 JP 2004-9125 A JP 2008-246504 A Japanese National Patent Publication No. 11-512029

  In the above-mentioned Patent Document 1, it is configured so that wrinkles are positively formed. However, in order to eliminate wrinkles in the rotary pull bending process, wrinkles are generally used. In Patent Documents 2 to 4, A wiper is provided. Among these, the wipers described in Patent Documents 2 and 4 have a wedge-shaped tip portion, and in Patent Document 2, there is concern about wear of the edge portion of the tip, and countermeasures are taken. In particular, there is a step between the wiper and the bending die along the pipe bending start line (usually the line where the surface including the rotation axis of the bending die intersects the groove inner surface of the bending die). Wrinkles due to steps cannot be avoided. In order to suppress this to the minimum, it is essential to maintain the wedge shape at the tip of the wiper. In particular, since the tip needs to be made as thin as possible, it is fragile and has poor durability. Also, periodic wear countermeasures are inevitable, and frequent replacement is required. In addition, since the initial setting of the bending process is difficult, a skilled technique is required. Therefore, it is difficult to continuously perform a large amount of bending.

  On the other hand, the wiper described as one embodiment in Patent Document 3 constitutes a part of the central die portion of the bending die divided into three in the vertical direction, and is formed with a concave portion having an arcuate cross section. (Described in paragraphs [0025] to [0030] of Patent Document 3), thereby describing that “a tip portion having an edge structure does not need to be formed and there is no possibility of a step between the bending die”. However, the explanation during this time is unclear. Temporarily, for the pipe to be processed, from the start to the end of the bending process, among the bending dies divided by three planes parallel to the pipe axis, the upper and lower side die parts contribute to the bending process, and the central part serves as the wiper. If the separation operation to function is performed, not only is it difficult to prevent the generation of wrinkles, but it is also difficult to appropriately perform the bending process itself, and a configuration that enables a desired bending process is possible. There is no disclosure.

  On the other hand, Patent Document 4 discloses that a bending die, a clamping die, and a pressure die can be exchanged for a die set in which a bending die, a clamping die, and a pressure die are pre-assembled for bending a tube having a different size or for a different type of tube bending operation. Although configured, the wiper die is not necessarily essential (described in page 11 of Patent Document 4). Therefore, in Patent Document 4, although attention is paid to the changeover function, a replaceable die set including a function that can appropriately prevent the generation of wrinkles is not disclosed. There is no suggestion of a suitable pipe bend mold unit and apparatus comprising the same.

  Then, this invention makes it a subject to provide the pipe bending type | mold unit which can perform the bending process with respect to a pipe appropriately, without worrying about generation | occurrence | production of a wrinkle. It is another object of the present invention to provide a pipe bending apparatus provided with a pipe bending die unit suitable for the bending process.

  Furthermore, the present invention provides a pipe bending die unit that can appropriately bend a pipe without worrying about the occurrence of wrinkles and that can be easily changed, and a pipe bending apparatus including the unit. This is another issue.

  In order to achieve the above object, the present invention includes a bending die having a pipe receiving groove having a semicircular cross section on the outer peripheral surface and driven to rotate around a rotating shaft, and the bending die is provided with a semicircular cross section on the outer peripheral surface. A gripping member having a circular first groove and having a fitting recess formed in the first groove and extending in a circumferential direction for a first predetermined distance in a plane perpendicular to the rotation axis; The outer peripheral surface has a second groove portion having a semicircular cross section, and has a fitting convex portion extending from the tip end portion of the second groove portion by a second predetermined distance in the circumferential direction. A counter pressure member that fits into the fitting recess and joins the first groove and the second groove to form the pipe-receiving groove having a semicircular cross section, and the rotation shaft as a central axis; A hollow shaft member that rotatably supports the gripping member and the counter pressure member, and an engaging portion that is accommodated in the hollow shaft member and engages with the hollow shaft member And a fixed shaft member having at least one fixed portion at one end, the counter pressure member and the gripping member are connected by a hinge connection through the hollow shaft member, and rotate relative to the rotation shaft. The structure is supported as possible.

  In the above pipe bending die unit, a part of the fitting convex portion is located on the front side in the traveling direction of the pipe with respect to a bending start position of the pipe to be processed, and the other portion of the fitting convex portion However, it is good to set it as the structure located in the back side with respect to the advancing direction of the said pipe with respect to the bending start position of the said pipe. Alternatively, the fitting portion of the fitting convex portion to be fitted into the fitting concave portion is located on the front side in the advancing direction of the pipe with respect to the bending processing start position of the pipe, and the first of the gripping member It is preferable that a contact portion between the groove portion and the second groove portion of the counter pressure member is located on the rear side in the traveling direction of the pipe with respect to the bending start position of the pipe.

  In each of the above pipe bending mold units, the counter pressure member has an annular rotation support portion rotatably supported by the hollow shaft member, and a part of the rotation support portion constitutes the fitting convex portion. And it is good to set it as the structure where the outer peripheral surface of the said rotation support part is a curved surface which forms a part of said semicircular pipe receiving groove.

  In each of the above pipe bending die units, the bending die is composed of a plurality of members divided by a plane orthogonal to the central axis of the hollow shaft member, and the plurality of members are connected to each other. It may be provided with a connecting member.

  Further, each of the pipe bending die units may include a sliding member interposed between the gripping member, the counter pressure member, and the hollow shaft member.

  In addition, the present invention grips a bending die having a pipe receiving groove having a semicircular cross section on the outer peripheral surface and driven to rotate around a rotating shaft, and a pipe to be processed disposed in the pipe receiving groove of the bending die. And a pressure die that presses the pipe in the bending die direction. The bending die has a first groove portion having a semicircular cross section on the outer peripheral surface, and is formed in the first groove portion. A gripping member having a fitting recess extending in a circumferential direction within a plane perpendicular to the rotation axis, and a second groove having a semicircular cross section on the outer peripheral surface, and the second A fitting convex portion extending in the circumferential direction from the tip of the groove portion by a second predetermined distance, and the fitting convex portion is fitted into the fitting concave portion and the first groove portion and the second groove portion. A counter pressure member that forms a pipe receiving groove having a semicircular cross section by coupling the rotation shaft to the central axis, and the gripping member and the front A hollow shaft member that rotatably supports the counter pressure member, and a fixed shaft member that is housed in the hollow shaft member and has an engaging portion that engages with the hollow shaft member and has a fixing portion at least at one end. The pipe bending type unit is configured such that the counter pressure member and the gripping member are connected by a hinge coupling via the hollow shaft member and are supported so as to be relatively rotatable about the rotating shaft. A processing apparatus is provided.

  In the above pipe bending apparatus, a part of the fitting convex part is located on the front side in the traveling direction of the pipe with respect to the pipe bending start position, and the other part of the fitting convex part is It is good to set it as the structure located in the back side with respect to the advancing direction of the said pipe with respect to the bending start position of the said pipe. Alternatively, the fitting portion of the fitting convex portion to be fitted into the fitting concave portion is located on the front side in the advancing direction of the pipe with respect to the bending processing start position of the pipe, and the first of the gripping member It is preferable that a contact portion between the groove portion and the second groove portion of the counter pressure member is located on the rear side in the traveling direction of the pipe with respect to the bending start position of the pipe.

  In each of the above pipe bending apparatuses, the counter pressure member has an annular rotation support portion rotatably supported by the hollow shaft member, and a part of the rotation support portion constitutes the fitting convex portion. And it is good to set it as the structure where the outer peripheral surface of the said rotation support part is a curved surface which forms a part of said semicircular pipe receiving groove.

  In each of the above pipe bending apparatuses, the bending die is composed of a plurality of members divided by a plane orthogonal to the central axis of the hollow shaft member, and the plurality of members are connected to each other. It may be provided with a connecting member.

  Furthermore, each said pipe bending apparatus WHEREIN: It is good also as what was provided with the sliding member interposed between the said holding member and the said counter pressure member, and the said hollow shaft member.

  In each of the above pipe bending apparatuses, a core metal is provided in which a tip portion is inserted into the pipe and driven so that the tip portion faces the pressure die in a predetermined rotation range of the bending die. It may be a thing.

  Since this invention is comprised as mentioned above, there exist the following effects. That is, in the pipe bend die unit of the present invention, the bend die constituting the pipe has the first groove portion having a semicircular cross section on the outer peripheral surface, is formed in the first groove portion, and is orthogonal to the rotation axis. A gripping member having a fitting recess extending in the circumferential direction for a first predetermined distance in the plane, a second groove portion having a semicircular cross section on the outer peripheral surface, and in a circumferential direction from the tip of the second groove portion A fitting convex portion extending a second predetermined distance, the fitting convex portion is fitted into the fitting concave portion, and the first groove portion and the second groove portion are joined to form a semicircular pipe receiving groove. A counter pressure member to be formed, a hollow shaft member having a rotation shaft as a central axis, and rotatably supporting the gripping member and the counter pressure member, and an engaging portion received in the hollow shaft member and engaged with the hollow shaft member A fixed shaft member having at least one fixed portion at one end, and the counter pressure member and the gripping member are hollow shaft members. Are connected by the hinged, since it is relatively rotatably supported around the rotational axis, it can be performed appropriately bending against the pipe without worrying about the occurrence of wrinkles. Moreover, if a plurality of pipe bending mold units are prepared according to the shape of the pipe to be processed, it is only necessary to select and replace the pipe bending mold unit according to the shape when bending various pipe shapes. Therefore, it is possible to provide a pipe bend die unit that can be easily changed and does not require adjustment after the change.

  In the above pipe bending die unit, a part of the fitting convex part is located on the front side in the pipe traveling direction with respect to the bending start position of the pipe to be processed, and the other part of the fitting convex part is the pipe. The configuration where the pipe is in the rearward direction with respect to the bending process start position, or the fitting part of the fitting convex part fitted into the fitting concave part is located at the pipe bending start position. The contact portion between the first groove portion of the gripping member and the second groove portion of the counter pressure member is located on the front side of the pipe in the direction of travel of the pipe. If it is set as the structure located in, a smooth bending process can be performed, without generating a wrinkle in a pipe.

  If the counter pressure member has an annular rotation support portion that is rotatably supported by the hollow shaft member, the counter pressure member can be reliably supported to be rotatable about the rotation shaft. If the part constitutes a fitting convex part and the outer peripheral surface of the rotation support part is a curved surface that forms a part of a pipe receiving groove with a semicircular cross section, the counter pressure member can be appropriately made of a single component. Can be formed in any shape.

  Further, in each of the above pipe bending die units, the bending die is composed of a plurality of members divided by a plane orthogonal to the central axis of the hollow shaft member, and a connecting member that connects each of the plurality of members to each other. If it is provided, the number of parts is increased as compared with the above-described configuration, but the parts can be manufactured with an accuracy according to the function required for each part, and the manufacture of each part becomes easy.

  Further, in each of the pipe bending die units described above, if the sliding member interposed between the gripping member and the counter pressure member and the hollow shaft member is provided, the gripping member and the counter pressure member smoothly rotate relative to each other. The operation can be performed and smoother bending can be performed.

  The pipe bending apparatus of the present invention includes a pipe bending die unit configured as described above, a gripping die for holding a pipe to be processed that is disposed in a pipe receiving groove of the bending die, and a pipe bending die. A pressure mold that presses in the direction is provided. By rotating the gripping mold and the bending mold while pressing the pipe in the bending mold direction with this pressure mold, it is possible to appropriately perform bending processing on the pipe without worrying about wrinkles. Can be done. Moreover, if a plurality of pipe bending mold units are prepared according to the shape of the pipe to be processed, it is only necessary to select and replace the pipe bending mold unit according to the shape when bending various pipe shapes. Since it is good, the setup can be easily changed, and adjustment after the setup is unnecessary. Therefore, automatic setup change by the robot is also possible.

  In the above pipe bending apparatus, a part of the fitting convex part is positioned on the front side in the pipe traveling direction with respect to the pipe bending start position, and the other part of the fitting convex part is a pipe bending process. The structure located on the rear side with respect to the starting direction of the pipe relative to the start position, or the fitting portion of the fitting convex portion fitted into the fitting concave portion is connected to the pipe bending start position. The abutting portion between the first groove portion of the gripping member and the second groove portion of the counter pressure member is located on the rear side in the pipe traveling direction with respect to the pipe bending start position. If it is the structure which is set, smooth bending process can be performed.

  If the counter pressure member provided in each of the above pipe bending apparatuses has an annular rotation support portion rotatably supported by the hollow shaft member, the counter pressure member reliably supports the rotation shaft around the rotation shaft. Further, a part of the rotation support part forms a fitting convex part, and the outer peripheral surface of the rotation support part is configured to be a curved surface forming a part of a semicircular pipe receiving groove. For example, the counter pressure member can be formed into an appropriate shape with a single component.

  Further, in each of the above pipe bending apparatuses, the bending die is composed of a plurality of members divided by a plane perpendicular to the central axis of the hollow shaft member, and a connecting member that connects each of the plurality of members to each other is provided. If it is provided, the number of parts is increased as compared with the above-described configuration, but the parts can be manufactured with an accuracy according to the function required for each part, and the manufacture of each part becomes easy.

  Further, in each of the above pipe bending apparatuses, if the gripping member and the sliding member interposed between the counter pressure member and the hollow shaft member are provided, the gripping member and the counter pressure member smoothly rotate relative to each other. The operation can be performed and smoother bending can be performed.

  Then, in each of the above pipe bending apparatuses, it is assumed that a tip metal is inserted into the pipe, and a metal core is driven so that the tip is opposed to the pressure die in a predetermined rotation range of the bending die. Bending with a small bending radius can be easily performed, and the bending limit for the pipe can be greatly improved.

It is a perspective view which shows the pipe bending apparatus which concerns on one Embodiment of this invention. It is a front view of the pipe bend die unit concerning one embodiment of the present invention. It is a disassembled perspective view of the pipe bending die unit which concerns on one Embodiment of this invention. It is sectional drawing of the pipe bend type | mold unit which concerns on one Embodiment of this invention, and is XX sectional drawing of FIG. It is a disassembled perspective view of the counter pressure member with which it uses for one Embodiment of this invention. It is a section perspective view showing the state at the time of the end of bending of the pipe bending device concerning one embodiment of the present invention. It is a disassembled perspective view of the pipe bending die unit which concerns on other embodiment of this invention. It is sectional drawing of the pipe bend type | mold unit which concerns on other embodiment of this invention, and is YY sectional view taken on the line of FIG. It is a side view of the pipe bending die unit which concerns on other embodiment of this invention. It is a bottom view of the pipe bend type unit concerning other embodiments of the present invention. It is a disassembled perspective view of the pipe bending die unit which concerns on other embodiment of this invention. It is sectional drawing of the pipe bend type | mold unit which concerns on other embodiment of this invention. It is a disassembled perspective view of the pipe bending die unit which concerns on another embodiment of this invention. It is a perspective view of the pipe bending die unit which concerns on another embodiment of this invention. It is a side view of the pipe bending die unit which concerns on another embodiment of this invention. It is a front view of the pipe bending die unit which concerns on another embodiment of this invention. It is sectional drawing of the pipe bend type | mold unit which concerns on another embodiment of this invention, and is ZZ sectional drawing of FIG. It is a bottom view of the pipe bending die unit which concerns on another embodiment of this invention. It is a perspective view of the pipe bending die unit which concerns on another embodiment of this invention. It is a front view of the pipe bending die unit which concerns on another embodiment of this invention. It is a disassembled perspective view of the pipe bending die unit which concerns on another embodiment of this invention. It is sectional drawing of the pipe bending die unit which concerns on another embodiment of this invention. It is a perspective view which shows the pipe by which the bending process was performed using the pipe bending die unit which concerns on embodiment of this invention. 1 is a perspective view showing an embodiment of a pipe bending apparatus equipped with a pipe bending die unit according to an embodiment of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a pipe bending mold unit according to an embodiment of the present invention, and a pipe bending apparatus according to an embodiment including a gripping mold 200 and a pressure mold 300 in addition to the pipe bending mold unit. And a bending die 100 having a pipe receiving groove (configured by first and second groove portions 11 and 21 described later) having a semicircular cross section on the outer peripheral surface and driven to rotate about the rotation axis (A). . In the pipe bending apparatus, the pipe P to be processed is gripped between the bending mold 100 and the gripping mold 200 and is driven forward while being pressed in the direction of the bending mold 100 by the pressure mold 300, and the compression load and shaft The pipe P is bent by the pressing load.

  The bending die 100 of the present embodiment includes a gripping member 10 and a counter pressure member 20, and as shown in FIGS. 1 and 2, the gripping member 10 is formed with a first groove 11 having a semicircular cross section. At the same time, a fitting recess 12 having a predetermined width is formed in the first groove 11 so as to extend a predetermined distance in the circumferential direction within a plane orthogonal to the rotation axis (A). The gripping member 10 is mounted on a base 13 (FIGS. 1 and 2) to be mounted by a fixed shaft member stud 60 having a rotation axis (A) as a central axis through a sleeve 70 of a hollow shaft member shown in FIG. (Indicated by a two-dot chain line). The stud 60 is formed in a bolt shape in which a large-diameter engaging portion 60a is formed at an intermediate portion of the stud 60 and a screw portion 60b serving as a fixing portion is formed at the tip, and the stud 60 is inserted into the communication hole 70a of the sleeve 70. The stud 60 is fixed by screwing 60b to the base 13. Thus, the gripping member 10 and the counter pressure member 20 are connected by a hinge connection via the sleeve 70 and supported by the stud 60 so as to be relatively rotatable about the rotation axis (A). Will be described in detail later. The locking member 80 is fixed to the gripping member 10 and the knock pin 27 is fixed to the counter pressure member 20, which will be described later.

  As shown in FIG. 3, the gripping member 10 has an annular recess 10b that forms a first groove 11 having a semicircular cross section, and extends in the circumferential direction within a plane orthogonal to the rotation axis (A). A fitting recess 12 having a predetermined width is provided. The fitting recess 12 is disposed at the bottom center of the annular recess 10b. Accordingly, the first groove 11 having a semicircular cross section includes a part of the fitting recess 12 and is continuous with the annular recess 10b. That is, the gripping member 10 of the present embodiment has a gripping portion 10a for gripping the pipe P (a joint surface with the gripping mold 200 is a flat surface) and an annular recess 10b formed continuously therewith, and these are integrated. Is formed. Thus, the first groove portion 11 has a continuous semicircular cross section of a semicircular groove portion 11a formed in the grip portion 10a and a semicircular groove portion 11b formed in the annular recess 10b. Have. In addition, in order to surely hold the pipe P in the groove portion 11a, a plurality of holding strips are provided in parallel in the circumferential direction of the groove portion 11a, like the inner peripheral surface of the holding die 200.

  As shown in FIG. 4, the gripping member 10 is formed with a stepped hole 10c in the order of a large-diameter hole, a medium-diameter hole, and a small-diameter hole from above in FIG. 4, and between the large-diameter hole and the medium-diameter hole. A step portion 10d is formed, a step portion 10e is formed between the medium diameter hole and the small diameter hole, and a small diameter hole holding hole 10f is formed in the lower part of FIG. Further, a groove portion 10g for connecting the spigot is formed in the radial direction on the lower end surface of the gripping member 10, and an arc-shaped convex portion 10h (only one of them appears in FIG. 4) sandwiching the groove portion 10g around the holding hole 10f. Is formed). That is, protrusions 13a and 13b (shown in FIGS. 1 and 2) for inlay coupling are formed on the base 13, and the protrusions 13a and 13b are fitted in the groove 10g to be inlay coupled. It is configured. Note that the lower end surface of the gripping member 10 is the same as that shown in FIG. 18 described later, and is configured such that the end surface of each arcuate convex portion 10 h is pressed against the base 13 during splicing.

  Further, as shown in FIGS. 3 and 4, a cylindrical bush 71 as a sliding member is mounted on the gripping member 10 around the sleeve 70, and a stepped portion 70 b that locks the bush 71 on the outer peripheral surface of the sleeve 70. Is formed. Thus, when the bush 71 and the sleeve 70 are inserted into the stepped hole 10 c of the gripping member 10 in a state where the fitting convexity 22 of the counter pressure member 20 is fitted to the fitting concave portion 12 of the gripping member 10. The lower end surface of the bush 71 is locked to the step portion 10d, and the lower end surface of the sleeve 70 is locked to the step portion 10e. Further, when the stud 60 is inserted into the communication hole 70a of the sleeve 70 and the engaging portion 60a contacts the upper end surface of the sleeve 70, the bush 71 is sandwiched between the step portion 70b and the step portion 10d. In addition, the sleeve 70 is held in a state of being sandwiched between the engaging portion 60a and the stepped portion 10e, the screw portion 60b extends from the holding hole 10f, and the pipe bending die shown in FIGS. Become a unit.

  On the other hand, as shown in FIGS. 1 and 2, the counter pressure member 20 is formed with a second groove portion 21 having a semicircular cross section on the outer peripheral surface, and in the circumferential direction from the tip portion of the second groove portion 21. A fitting convex portion 22 is formed so as to extend a predetermined distance to the first groove portion 11 of the gripping member 10 and the counter pressure member when the fitting convex portion 22 is fitted into the fitting concave portion 12. A pipe receiving groove having a semicircular cross section is formed by the 20 second groove portions 21. As shown in FIG. 3, the counter pressure member 20 has a rotation support portion 23, and this rotation support portion 23 is rotatably supported by the sleeve 70 (and the stud 60) around the virtual rotation axis (A). The fitting convex portion 22 is configured by a part of the rotation support portion 23.

  As shown in FIG. 3, the counter pressure member 20 is rotatably supported on the sleeve 70 via a curved surface portion (counter pressure portion) 20 a disposed so as to be in contact with the annular recess 10 b and a bush 71 ( That is, a rotation support portion 23 that is pivotally supported around the rotation axis (A) is integrally formed, and a fitting convex portion 22 is constituted by a part of the rotation support portion 23. Therefore, the outer peripheral surface of the rotation support portion 23 is formed in a curved surface, and is configured to form a pipe receiving groove having a semicircular cross section together with the first groove portion 11 of the gripping member 10. That is, the counter pressure member 20 is formed with a second groove portion 21 having a semicircular cross section, and the end surface shape of the second groove portion 21 contacting the first groove portion 11 of the gripping member 10 corresponds to FIG. As shown by the contact portion (R), it is curved in a front view. And the outer peripheral side surface 22a of the fitting convex part 22 (namely, outer peripheral side surface of the rotation support part 23) is formed in the curved surface, and when the fitting convex part 22 is fitted by the fitting recessed part 12 of the holding member 10. FIG. A part of the semicircular cross section of the first groove portion 11 of the gripping member 10 is formed, and a pipe receiving groove having a semicircular cross section is formed by both.

  As shown in FIG. 3, the counter pressure member 20 of the present embodiment includes a first member 20 x that constitutes the rotation support portion 23, and a second member 20 y that constitutes the second groove portion 21 and the fitting convex portion 22. The second member 20y is divided into two parts, and only the second member 20y including a portion that is easily worn is replaceable. Further, as shown in FIG. 5, the first member 20x is divided into a member including the main portion 23x of the rotation support portion 23 and the joint portion 25 and a support member 26, and a part 23y of the rotation support portion 23 It is good also as a structure which joins the 2nd member 20y which consists of the main-body part 24, for example with a volt | bolt. Thus, when the counter pressure member 20 is replaced, it is only necessary to replace the second member 20y including the portion 23y having a large wear, so that not only the replacement operation becomes easy, but also long-term use. From this point of view, the inexpensive counter pressure member 20 can be provided, and the cost is reduced.

  Further, the counter pressure member 20 shown in FIG. 5 is formed with a rib 23a in which at least a part in the circumferential direction of the rotation support portion 23 formed integrally with the main body portion 24 extends radially outward. . Since the rib 23a cannot make the skirt at the boundary with the curved surface portion 20a of the rotation support portion 23 thicker than necessary in order to avoid interference with other devices, stress concentration on the skirt is reduced. In order to relieve, a contact surface that extends in the tangential direction of the annular portion of the rotation support portion 23 and contacts the support member 26 is formed at the tip thereof. In addition, although the rotation support part 23 of this embodiment is formed in cyclic | annular form, you may form the rotation support part 23 in C shape by making parts other than the fitting convex part 22 into a space | gap.

  As described above, as shown in FIGS. 1 and 2, the gripping member 10 and the counter pressure member 20 are centered on the rotation axis (A) (the central axis of the stud 60 and the sleeve 70), and the sleeve 70 (and the bush 71). ), And the screw portion 60b of the stud 60 is screwed to the base 13 so that the gripping member 10 and the counter pressure member 20 are relatively rotatably supported. Fixed to. In the present embodiment, the gripping member 10 fixed to the base 13 is supported so as to be rotationally driven with respect to the counter pressure member 20 fixed to a predetermined position of an apparatus (not shown). Then, the position where the locking tool 80 fixed to the predetermined position of the gripping member 10 contacts the knock pin 27 fixed to the counter pressure member 20 is set as the initial relative position of the grip member 10 and the counter pressure member 20. It is configured.

  As shown in FIG. 2, the gripping member 10 and the counter pressure member 20 are fitted on the basis of a bending start position (indicated by a one-dot chain line S in the vertical direction in FIG. 2) when bending the pipe P. The fitting portion with the fitting convex portion 22 not included in the plane perpendicular to the rotation axis (A) in the concave portion 12 (two planes including (H) shown in FIG. 2 and parallel to the plane perpendicular to the paper surface of FIG. 2). (F) is located on the front side in the traveling direction of the pipe P (the right side of S in FIG. 2), and the first groove portion 11 of the gripping member 10 and the second groove portion 21 of the counter pressure member 20 are in the rotational direction. It connects so that a contact part (R) may be located in the back side (left side of S in FIG. 2) with respect to the advancing direction of the pipe P. As shown in FIG. In other words, the fitting portion (F) in the rotational direction of the fitting convex portion 22 fitted into the fitting concave portion 12 is positioned on the front side in the traveling direction of the pipe P with respect to the bending start position of the pipe P. The rotational contact portion (R) between the first groove portion 11 of the gripping member 10 and the second groove portion 21 of the counter pressure member 20 is rearward in the direction of travel of the pipe P with respect to the bending start position of the pipe P. Located on the side.

  Thus, as shown in FIGS. 1 and 2, since the pipe bending die unit is constituted by the bending die 100 in which the gripping member 10 and the counter pressure member 20 are arranged at the initial relative position, the pipe to be processed is formed. If a plurality of pipe bending die units are prepared according to the shape of P, when bending various pipe shapes, it is only necessary to select and replace the pipe bending die unit according to the shape. Replacement can be performed easily. In particular, as described above, since the initial relative positions of the gripping member 10 and the counter pressure member 20 can be set in advance by the locking tool 80 and the knock pin 27, adjustment after changing the stage is unnecessary, and skill can be improved. It can be easily adjusted without any need. Furthermore, if the pipe bending die unit includes the gripping die 200 and the pressure die 300 to form a unit, a pipe bending tool assembly that can be easily changed and adjusted can be provided.

  The overall operation of the pipe bending apparatus shown in FIG. 1 will be described. First, in the state where the locking tool 80 is held at the initial relative position in contact with the knock pin 27, the bending target portion of the body portion of the pipe P is Then, the bending tool 100 is placed at the bending start position (S in FIG. 2), and the same metal core (also called a mandrel, indicated by M in FIG. 1) is inserted into the pipe P as before. The core metal M has ball cores M1 and M2 supported in a tiltable manner at the tip end portions thereof as shown in FIG. 6 (however, hatching is omitted in view of visibility). Gold M1 and M2 are inserted into the pipe P and driven so as to be interposed between the bending die 100, the gripping die 200, and the pressure die 300 within a predetermined rotation range of the bending die 100. Next, the gripping mold 200 and the pressure mold 300 are driven in the direction of the bending mold 100, and the tip of the pipe P is gripped between the gripping member 10 of the bending mold 100 and the gripping mold 200, and the body portion of the pipe P Is pressed between the counter pressure member 20 of the bending die 100 and the pressure die 300.

  Subsequently, the pipe P is driven forward while the body portion of the pipe P is pressed against the counter pressure member 20 by the pressure die 300 in a state where the tip portion of the pipe P is held between the holding member 10 and the holding die 200. At the same time, when the gripping die 200 and the gripping member 10 are driven to rotate about the rotation axis (A), the pipe P is sequentially inserted into the pipe receiving grooves (first and second groove portions 11, 21) of the bending die 100. A pipe P that is bent so as to be wound is formed as shown in FIG. During this time, a large pressure is applied in the axial direction and the radial direction of the pipe P. However, if the pipe bend die unit is used, the pipe P can be controlled to be thickened by compressive deformation of the bent inner portion of the pipe P. In addition, the thickness of the bent outer portion of the pipe P can be increased, the thickness of the bent outer portion of the pipe P can be prevented from being reduced, and an appropriate tube thickness can be maintained even in the bent portion.

  Thus, the pipe P that has been bent using the pipe bend die unit of the present embodiment corresponds to the fitting portion of the fitting concave portion 12 and the fitting convex portion 22 as shown in FIG. Although a slightly thick portion (bump-shaped portion) is formed at a position, a portion that continues to this is a smooth curved surface. Specifically, the thickness gradually changes at the portion indicated by a thin line in FIG. 23, and the flowing meat is fitted into the fitting portion (F in FIG. 2) to form the thick portion TP1. Although the thick portions TP2 and TP3 are formed along the contact portion (R in FIG. 2), the portion indicated by a thin line in FIG. 23 is formed in a smooth curved surface and does not correspond to a so-called wrinkle. There is no need to worry about the occurrence of the parts TP1, TP2, and TP3. Rather, the bent pipe in which these thick portions TP1, TP2, and TP3 are formed serves as proof that the bending process has been performed using the pipe bending die unit of the present embodiment, and supports the processing quality.

  As described above, the bending die 100 according to the present embodiment includes the gripping member 10 and the counter pressure member 20, which serve as the central axis of the stud 60, that is, the rotation axis (A) via the sleeve 70 (and the bush 71). Since they are connected by a hinge connection at the center and are supported so as to be relatively rotatable about the rotation axis (A), the counter pressure member 20 is connected (via the pipe P) as the pipe P is bent. While being pressed by the pressure mold 300, the gripping member 10 can rotate relative to the rotation axis (A). Therefore, the gripping member 10 rotates in the circumferential direction away from the counter pressure member 20 from the bending start position (S in FIG. 2) with respect to the pipe P.

  As described above, the gripping member 10 and the counter pressure member 20 are connected via the sleeve 70 (and the bush 71), and the level difference that may occur between the grip member 10 and the counter pressure member 20 is suppressed to be small. Yes. For this reason, even if a larger axial pushing load and compressive load are applied to the pipe P than before, the plastic deformation accompanying the bending process can be appropriately controlled. Moreover, when the gripping member 10 is rotationally driven with respect to the counter pressure member 20, the torque due to the relative rotation between the gripping member 10 and the counter pressure member 20 is not directly transmitted to the stud 60, and the sleeve 70 (and bushing). 71). As a result, the stud 60 screwed to the base 13 is not loosened (by so-called co-rotation), and a stable fixed state can be maintained.

  FIGS. 7 to 10 relate to another embodiment of the pipe bend die unit, and the grip portion 10a is formed integrally with the grip member 10, whereas the grip portion 10a portion is separated ( 7), and is joined to a main body (indicated by 10x in FIG. 7 and the like) constituting the annular recess 10b. That is, a screw (not shown) is inserted into the holding portion 10y from the mounting holes 14 and 15, and is screwed into a screw hole (not shown) of the main body 10x to be fixed to the main body 10x. Thus, a continuous semicircular cross section is formed by the semicircular groove 11a formed in the grip 10a of the separate body 10y and the semicircular groove 11b formed in the annular recess 10b of the main body 10x. The 1st groove part 11 which has is comprised. In addition, about the member substantially the same as the above-mentioned embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 8, the gripping member 10 (main body 10x) is formed with a stepped hole 10c as in FIG. 4, but in this embodiment, only the large diameter hole and the medium diameter hole are small diameter holes. Is not formed, a step portion 10d is formed between the large-diameter hole and the medium-diameter hole, and a medium-diameter hole holding hole 10j is formed in the lower part of FIG. As shown in FIGS. 8 and 10, a groove portion 10g for spigot coupling is formed in the radial direction on the lower end surface of the gripping member 10, and an arcuate convex portion 10h on both sides sandwiching the groove portion 10g around the holding hole 10j. Is formed. Therefore, as shown in FIG. 8, a sleeve 70 longer than the sleeve 70 of FIG. 4 (the sign is the same as the former) is inserted into the holding hole 10j, but the lower end surface is exposed from the opening of the holding hole 10j. When the convex portions 13a and 13b (shown in FIGS. 1 and 2) of the base 13 are fitted in the groove 10g and are joined together, the lower end surface of the sleeve 70 is configured to come into contact with the base 13. Has been. Thus, the bush 71 and the sleeve 70 are inserted into the stepped hole 10c in a state where the fitting convex portion 22 of the counter pressure member 20 is fitted to the fitting concave portion 12 of the gripping member 10 (main body 10x). 71 is held between the engaging portion 60a of the stud 60 and the stepped portion 70b of the sleeve 70, and the lower end surface of the sleeve 70 is held in contact with the base 13, and the state shown in FIG. Become.

  11 and 12 relate to still another embodiment of the pipe bend die unit, and instead of the bush 71 described above, a cylindrical sliding member (hereinafter simply referred to as a needle bearing) in which a plurality of needle bearings are arranged in parallel. ) 72, and a smoother rotation of the counter pressure member 20 can be ensured. In addition, since both the bush 71 and the needle bearing 72 can be easily attached / detached, they can be appropriately replaced according to the wear state.

  In the present embodiment, the gripping member 10 (main body 10x) is formed with a stepped hole 10c as in FIG. 4, but only the large diameter hole and the medium diameter hole are not formed with the small diameter hole. A step portion 10e is formed between the large-diameter hole and the medium-diameter hole, and a small-diameter hole holding hole 10f is formed in the lower part of FIG. Thus, the needle bearing 72 and the sleeve 70 are inserted into the stepped hole 10c in a state where the fitting convex portion 22 of the counter pressure member 20 is fitted to the fitting concave portion 12 of the gripping member 10 (main body 10x). The needle bearing 72 is held between the engaging portion 60a of the stud 60 and the step portion 70b of the sleeve 70, and the sleeve 70 is held in a state of being held between the engaging portion 60a and the step portion 10e. Then, the screw part 60b extends from the holding hole 10f, and the state shown in FIG.

  Furthermore, as another embodiment, as shown in FIGS. 13 to 18, the main body 10x is constituted by an upper mold 40 and a lower mold 50 which are divided by a plane orthogonal to the rotation axis (A). The gripping member 10 can be configured by joining the body 10y (the gripping portion 10a). That is, as shown in FIG. 17, the upper mold 40 and the lower mold 50 are formed with annular step portions 41 and 42 and a central hole 43, and annular step portions 51 and 52 and a central hole 53, respectively, and opposite end faces. Are formed with key grooves 44 and 54, and with the key 45 fitted thereto, a pin 46 is inserted into a locking hole (not shown) of the upper die 40 and the lower die 50, and the key 45 and The upper die 40 and the lower die 50 are joined via the pin 46, and are configured to be bolted, for example.

  Thus, the sleeve 70 and the bush 71 are respectively interposed between the annular step portions 41 and 42 of the upper die 40 and the annular step portions 51 and 52 of the lower die 50, and the upper die 40 and the lower die 50 are joined. The The separate body 10y (gripping part 10a) is fixed to the main body 10x (upper mold 40 and lower mold 50), and the stud 60 is the central hole 43 of the upper mold 40, the rotation support part 23 of the counter pressure member 20, and the lower mold 50. When inserted through the central hole 53, the pipe bending die unit shown in FIGS. In the present embodiment, the fitting convex portion 22 of the counter pressure member 20 is interposed between the upper mold 40 and the lower mold 50, but the clearance between the upper mold 40 and the lower mold 50 is the above-described sleeve. Since the clearance is not distorted even if the stud 60 is firmly fastened to the base 13 by the stud 60, the fitting convex portion 22 is smoothly rotated between the upper die 40 and the lower die 50. The operation is ensured, and as a result, smooth relative rotation of the gripping member 10 and the counter pressure member 20 is ensured.

  Further, as shown in FIG. 13, sliding members 90 formed of graphite or the like are embedded in the upper and lower end surfaces of the upper mold 40 and the lower mold 50, so that the gripping member 10 and the counter pressure member 20 can be rotated more smoothly. Is ensured, wear of the fitting convex portion 22 and the like is reduced, and durability is improved. In addition, since the other structure is the same as that of the above-mentioned embodiment, about the substantially same member, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  Next, as still another embodiment, as shown in FIG. 19 and FIG. 20, the rotating shaft (A) is formed in a form in which a plurality of bending dies 100a and 100b including the gripping member 10 and the counter pressure member 20 are stacked. It can also be set as the structure supported so that rotation is possible. Each of the gripping member 10 and the counter pressure member 20 is connected by a hinge connection centering on the rotation axis (A). In the bending dies 100a and 100b, the upper die 40 shown in FIGS. And the main body 10x of the holding member comprised by the upper mold | type and lower mold | type similar to the lower mold | type 50 becomes the aspect on which 2 steps | paragraphs were laminated | stacked.

  That is, as shown in an exploded perspective view in FIG. 21, the three members B1 to B3 (and the stud 60 and the sleeve 70) constitute two gripping member main bodies 10xa and 10xb, and the main body 10xa is an upper die 401 (member B1). And the lower die 501 (part of the member B2), and the main body 10xb is constituted by the upper die 402 (part of the member B2) and the lower die 502 (part of the member B3), respectively. Are formed with annular recesses 10b1 and 10b2. And as shown in FIG. 22, the bush 71 similar to the above-mentioned embodiment is interposed between the main bodies 10xa and 10xb and the sleeve 70, respectively.

  Further, the pins 46a and 46b are inserted in the state where the keys 45a and 45b are fitted in the key grooves (not shown) formed on the opposing end surfaces of the upper molds 401 and 402 and the lower molds 501 and 502, and the key 45a And 45b and the pins 46a and 46b, the upper molds 401 and 402 and the lower molds 501 and 502 are joined together, for example, bolted. In addition, as shown to FIG. 19 thru | or 21, respectively, the holding tools 10ya and 10yb which have a different groove part shape according to a process target are joined to the main bodies 10xa and 10xb, and each holding member is comprised.

  Thus, since the two bending dies 100a and 100b are held in a state where the sleeve 70 penetrates them, the positioning of both is easy, and the upper dies 401 and 402 and the lower dies 501 and 502 are easy to position. Can be set to an appropriate value by the above-described sleeve 70, so that a smooth rotation operation of the fitting convex portion 22 (smooth relative rotation of the gripping member 10 and the counter pressure member 20) is ensured. . Also in this embodiment, as shown in FIG. 21, the sliding members 90 are embedded in the upper and lower end surfaces of the upper molds 401 and 402 and the lower molds 501 and 502, so that the gripping member 10 and the counter pressure member 20 are more smoothly relative to each other. Rotation is ensured, wear of the fitting convex portion 22 and the like is reduced, and durability is improved.

  The pipe bending apparatus 1 to which the pipe bending die unit of each of the above embodiments is mounted is configured as shown in FIG. 24, for example, and is provided with a pipe chuck CH that holds the pipe P to be processed, and advances the pipe P. A carriage CR that drives and applies a shaft pushing load is provided. By rotationally driving (indexing) the pipe chuck CH, the bending direction of the pipe P can be changed, thereby enabling three-dimensional bending. The gripping mold 200 is arranged on the rotary table 2 and is configured to be driven to rotate about the rotation axis (A) (the center axis of the stud 60 shown in FIG. 24).

  In this pipe bending apparatus 1, for example, the three gripping members 10 and the counter pressure member 20 are driven to rotate relative to each other via the sleeve 70 as in the pipe bending die unit shown in FIGS. 19 to 22. The pipe bending die unit (denoted by DU in FIG. 24) configured in the above is fixed to the base 13 by the stud 60. A connection support member 91 that connects and supports the three gripping members 10 shown in FIG. 24 and a connection support member 92 that connects and supports the three counter pressure members 20 serve as the central axis of the stud 60 (and the sleeve 70). It is configured to be rotationally driven around the center and to control the relative movement of the gripping member 10 and the counter pressure member 20. In FIG. 24, the connecting support member 92 is connected to the driving device DR via the link 93, and the three counter pressure members 20 are configured to move simultaneously. You may comprise so that the pressure member 20 may drive-control each separately.

10 gripping members 10b, 10b1, 10b2 annular recesses 10x, 10xa, 10xb main bodies 10y, 10ya, 10yb gripping tools 11, 11a, 11b first grooves 12, 12xa, 12xb fitting recesses 13 base 20 counter pressure member 21 second Groove portion 22 fitting convex portion 23 rotation support portion 26 support member 27 knock pin 30 base 40, 401, 402 upper die 50, 501, 502 lower die 60 stud (fixed shaft member)
70 Sleeve (hollow shaft member)
71 Bush (Sliding member)
72 Needle bearing (sliding member)
80 Locking tool 100, 100a, 100b Bending die 200 Grasping die 300 Pressure die A Rotating shaft P Pipe

Claims (13)

A bending die having a pipe receiving groove with a semicircular cross section on the outer peripheral surface and driven to rotate around the rotation axis,
The bending mold is
A first recess having a semicircular cross section on the outer peripheral surface, and a fitting recess formed in the first recess and extending a first predetermined distance in the circumferential direction within a plane orthogonal to the rotation axis. A gripping member having
The outer peripheral surface has a second groove portion having a semicircular cross section, and has a fitting convex portion extending from the tip end portion of the second groove portion by a second predetermined distance in the circumferential direction. A counter pressure member that fits into the fitting recess and combines the first groove and the second groove to form the semicircular pipe receiving groove;
A hollow shaft member having the rotation shaft as a central axis and rotatably supporting the gripping member and the counter pressure member;
A fixed shaft member housed in the hollow shaft member and having an engaging portion that engages with the hollow shaft member and having a fixed portion at least at one end;
A pipe bending die unit in which the counter pressure member and the gripping member are connected by a hinge connection via the hollow shaft member, and are supported so as to be relatively rotatable about the rotation shaft. A part of the fitting convex part is located on the front side in the advancing direction of the pipe to be machined with respect to the pipe bending start position, and the other part of the fitting convex part starts bending the pipe. The pipe bending die unit according to claim 1, wherein the pipe bending die unit is located rearward with respect to the position with respect to the traveling direction of the pipe. The fitting part of the fitting convex part fitted to the fitting concave part is located on the front side in the traveling direction of the pipe with respect to the bending start position of the pipe to be processed, and the first of the gripping member 2. The pipe bending die according to claim 1, wherein an abutting portion between the groove portion of the pipe and the second groove portion of the counter pressure member is located on a rear side in the traveling direction of the pipe with respect to a bending start position of the pipe. unit. The counter pressure member has an annular rotation support portion rotatably supported by the hollow shaft member,
The part of the rotation support part constitutes the fitting convex part, and the outer peripheral surface of the rotation support part is a curved surface forming a part of the semicircular pipe receiving groove. The pipe bend die unit according to any one of the above. The bending die is composed of a plurality of members divided by a plane orthogonal to the central axis of the hollow shaft member,
The pipe bending die unit according to any one of claims 1 to 4, further comprising a connecting member that connects each of the plurality of members to each other. The pipe bending die unit according to any one of claims 1 to 5, further comprising a sliding member interposed between the gripping member, the counter pressure member, and the hollow shaft member. A bending die having a pipe receiving groove with a semicircular cross section on the outer peripheral surface and driven to rotate around a rotation axis;
A gripping mold for gripping the pipe to be processed disposed in the pipe receiving groove of the bending mold;
A pressure die that presses the pipe in the bending die direction;
The bending mold is
A first recess having a semicircular cross section on the outer peripheral surface, and a fitting recess formed in the first recess and extending a first predetermined distance in the circumferential direction within a plane orthogonal to the rotation axis. A gripping member having
The outer peripheral surface has a second groove portion having a semicircular cross section, and has a fitting convex portion extending from the tip end portion of the second groove portion by a second predetermined distance in the circumferential direction. A counter pressure member that fits into the fitting recess and combines the first groove and the second groove to form the semicircular pipe receiving groove;
A hollow shaft member having the rotation shaft as a central axis and rotatably supporting the gripping member and the counter pressure member;
A fixed shaft member housed in the hollow shaft member and having an engaging portion that engages with the hollow shaft member and having a fixed portion at least at one end;
A pipe bending apparatus in which the counter pressure member and the gripping member are connected by a hinge coupling through the hollow shaft member, and are supported so as to be relatively rotatable about the rotating shaft to constitute a pipe bending die unit. . A part of the fitting convex part is located on the front side in the traveling direction of the pipe with respect to the bending start position of the pipe, and the other part of the fitting convex part is located at the bending start position of the pipe. The pipe bending apparatus according to claim 7, wherein the pipe bending apparatus is located on the rear side with respect to the traveling direction of the pipe. The fitting portion of the fitting convex portion to be fitted into the fitting concave portion is located on the front side in the traveling direction of the pipe with respect to the bending start position of the pipe, and the first groove portion of the gripping member The pipe bending apparatus according to claim 7, wherein a contact portion between the counter pressure member and the second groove portion is located on a rear side in a traveling direction of the pipe with respect to a bending start position of the pipe. The counter pressure member has an annular rotation support portion rotatably supported by the hollow shaft member,
10. A part of the rotation support part constitutes the fitting convex part, and an outer peripheral surface of the rotation support part is a curved surface forming a part of the semicircular pipe receiving groove. The pipe bending apparatus as described in any one of Claims. The bending die is composed of a plurality of members divided by a plane orthogonal to the central axis of the hollow shaft member,
The pipe bending apparatus according to any one of claims 7 to 10, further comprising a connecting member that connects each of the plurality of members to each other. The pipe bending apparatus according to any one of claims 7 to 11, further comprising a sliding member interposed between the gripping member, the counter pressure member, and the hollow shaft member. 13. The metal core according to claim 7, further comprising a mandrel inserted into the pipe and driven so that the tip is opposed to the pressure die within a predetermined rotation range of the bending die. The pipe bending apparatus as described.

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