JP2009297751A - Bending device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bending device with which a small-radius bending the radius of which is equal to or less than the diameter of a tube is achieved and the small-radius bending is performed. <P>SOLUTION: In a bending device 50 with which bending work of a member 15 to be worked is performed, by bringing the member 15 to be worked into contact with a turntable 19 which is made rotatable around the axis of rotation, a lower die 1 which is fixed to the turntable, an upper die 2 which is superposed on the lower die 1, a shaft 12 for fixing the lower die 1 and the upper die 2 to the turntable 19 and bending surfaces 22, 23, 24, 25, 26 which are located on the periphery of the shaft 12 when the lower die 1 and the upper die 2 are superposed each other, and rotating the turntable 19 around the axis of rotation, fitting parts 7, 8, 9 are provided to the mating face between the lower die 1 and the upper die 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a bending apparatus suitable for use in bending a tube for constituting a tube element applied to a superheater such as a land boiler, a reheater, a economizer, and the like.

Superheaters such as land boilers, reheaters, economizers, and the like are formed of tube elements composed of a plurality of tubes. The tube element is formed with bent portions having different radii of curvature.
Conventionally, as a method for performing such bending, for example, as described in Patent Document 1, there is a bending method in which a pipe is bent at an arbitrary angle.
Specifically, a bending die having a concave portion of a required radius fixed to a rotary table with a bolt is provided, and one of pipes as a workpiece is fixed to the concave portion of the bending die by a clamp die, and the other is a pressure die. Abutted. Then, by rotating the rotary table, the pipe is bent so as to be wound around the bending die.

  Further, according to the circular fixed die for pipe bending described in Patent Document 2, a pipe as a workpiece is brought into contact with a fixed die whose center is fixed by a shaft, and a rotating shaft and The first groove portion and the second groove portion, which are two curved grooves having different distances, are provided. Then, one of the pipes abuts the fixed mold and is fixed by the clamping chuck, the other is abutted and fixed to the clamping mold, and the clamping mold is piped to the stationary mold in accordance with the rotation of the stationary mold. Bending with different bending radii is easily performed by rotating in the same direction while pressing.

JP-A-51-86061 JP-A-9-57356

  By the way, in the tube element, as shown in FIG. 6, the tube element is formed of a plurality of tubes having different bending radii, and the tube located inside the tube element has a curvature of the bent portion than the outer tube. A small-diameter bending process of a maximum radius of 180 degrees with a radius of curvature that is small, that is, equal to or less than the tube diameter must be performed.

  However, in Patent Document 1, when performing this small-diameter bending process, it is necessary to use a small-diameter bending die. At the same time, the bending die and the shaft that fixes the bending die are also reduced in diameter. As a result of the pressing force acting, the mold or bolt may be damaged, and there is a possibility that the diameter cannot be reduced until the small diameter bending can be handled. Similarly, in Patent Document 2, when performing a small-diameter bending that is equal to or smaller than the pipe diameter, it is necessary to reduce the diameter of the fixed mold, and accordingly, it is necessary to reduce the diameter of the shaft that fixes the fixed mold. As mentioned above, there is a concern that the fixed mold and the shaft may be damaged, and there is a problem that it is not possible to cope with small-diameter bending.

  An object of the present invention is to provide a bending apparatus capable of performing small-diameter bending by realizing small-diameter bending equal to or less than the tube diameter without damaging the shaft and the mold in view of the above problems. To do.

In order to achieve the above object, the present invention provides the following means.
The bending apparatus according to the present invention includes a turntable that is rotatable about a rotation axis, a lower mold that is fixed on the turntable, an upper mold that overlaps the lower mold, A shaft for fixing the lower mold and the upper mold integrally, and a workpiece to be brought into contact with a bending surface positioned around the shaft when the lower mold and the upper mold are overlapped In the bending apparatus for bending the workpiece by rotating the turntable around the rotation axis, a fitting portion is provided on the mating surface of the lower mold and the upper mold. It is characterized by being.

According to the present invention, the fitting portion is provided on the mating surface of the lower mold and the upper mold. When the rotating table is rotated around the rotation axis during bending, the rotational force is transmitted from the rotating table to the lower mold, and further from the lower mold to the upper mold. When the rotational force is transmitted from the lower mold to the upper mold, it is transmitted not only through the shaft but also through the fitting portion. Therefore, the load applied to the shaft is reduced as compared with the case where the rotational force is transmitted only by the shaft, and the diameter of the shaft can be reduced. If the diameter of the shaft can be reduced, the radius of curvature of the bending surface located around the shaft can also be reduced. Thereby, the small diameter bending of a to-be-processed member is realizable.
In addition, when the workpiece is placed between the lower mold and the upper mold and the molds are fixed at the time of processing, the fitting part is fitted at the same time when the upper mold and the lower mold are overlapped. Therefore, it is not necessary to use, for example, a bolt or the like in order to provide a fixing portion different from the shaft. Therefore, the workpiece can be set in a very short time. This is particularly effective when the workpiece is rapidly bent after being heated.

  In the above bending apparatus, the bending surface includes a first straight part, a U-turn part formed continuously from the first straight part, and the U-turn part continuously from the U-turn part. The U-shaped portion is formed in a U-shape formed by a second straight portion facing the straight portion, and a through-hole into which a shaft is inserted is provided in the vicinity of the inner end portion of the U-turn portion. Is formed between the first straight line portion and the second straight line portion at a position away from the through hole.

  According to the present invention, the bending surface faces the first straight portion, the U-turn portion formed continuously from the first straight portion, and the first straight portion continuously from the U-turn portion. It is U-shaped formed by the second straight part, and an insertion hole for inserting a shaft is provided near the inner end of the U-turn part, and the fitting part is separated from the insertion hole. It was decided to form between the first straight line portion and the second straight line portion at the same position. When the rotational force is transmitted to the shaft, the load applied to the shaft is further reduced as the fitting portion is located away from the shaft. Therefore, the diameter of the shaft can be reduced.

  Furthermore, in any one of the bending apparatuses described above, a plurality of the fitting portions are arranged and arranged between the first straight portion and the second straight portion. And

According to the present invention, a plurality of fitting portions are arranged and arranged between the first straight portion and the second straight portion. It is necessary to reduce the load applied to the shaft as the shaft becomes smaller in diameter. By arranging a plurality of fitting portions in the mold in an aligned manner, when the rotational force is transmitted to the shaft, the load applied to the shaft is distributed to the plurality of fitting portions and further reduced. Become. Therefore, it is possible to perform bending using a shaft having a smaller diameter. Furthermore, it is possible to prevent the mold from being displaced during processing.
In addition, when providing a some fitting part, it is preferable to provide in the position which goes between a 1st linear part and a 2nd linear part, and goes to a shaft in order from the position furthest away from the shaft.

  Furthermore, in any of the above bending apparatuses, the fitting portion is a convex portion and a concave portion, the convex portion is cylindrical, and the concave portion is a cylindrical hole. .

According to the present invention, the fitting portion has a convex portion having a cylindrical shape and a concave portion having a cylindrical hole. If it is a cylindrical shape or a cylindrical hole, it is easy to process, and it is possible to easily provide an uneven portion on the mold, thereby reducing the load on the shaft.
In addition, although the uneven | corrugated | grooved part of this invention is made into the cylindrical shape, even if it is shapes, such as a triangle and a rectangle, there exists the same effect | action.
Moreover, even if it is uneven | corrugated | grooved parts, such as a triangle and a rectangle, a plurality can be provided and there exists an effect | action similar to a cylindrical shape.
Furthermore, the concavo-convex portion may be a ring-shaped concavo-convex portion such as a donut shape, and the load on the shaft can be reduced similarly to the cylindrical shape. If it is a ring-shaped convex part, the outer peripheral part circle | round | yen except the center part circle | round | yen will be formed in convex shape, and a recessed groove will be formed in the outer peripheral part except the central part circle | round | yen. Therefore, it is possible to further prevent the mold from being displaced by fitting at the center circle of the concavo-convex portion and the two outer circles.
When providing a plurality of uneven portions, a cylindrical uneven portion and a ring-shaped uneven portion may be provided in combination.

  Furthermore, in any of the above bending apparatuses, the fitting portion is a key and a key groove.

According to the present invention, in any of the bending apparatuses described above, the fitting portion is a key and a key groove. As a result, the key and the keyway can be easily manufactured without requiring a significant cost increase because the key and the key groove are straight and easy to manufacture.
The key and the key groove are preferably provided in a cross shape on the upper mold and the lower mold. By adopting the cross shape, the load applied to the shaft and the mold is received in the longitudinal direction and the lateral direction, so that the load applied to the shaft is reduced and the shift of the mold can be prevented.

  Further, in any one of the above bending apparatuses, a fixing member for fixing the workpiece is provided on the bending surface having the first straight portion, and an outer end of the fixing member is provided. The portion is provided with a second key and a second key groove in a direction along the first straight portion.

According to the present invention, a fixing member for fixing the workpiece to be processed is provided on the lower die and the upper die on the bending surface having the first straight portion, and the outside of the fixing member. The second key and the second key groove are provided at the end portion in a direction along the first linear portion. Thereby, since the load concerning a shaft is distributed also to a 2nd key and a 2nd keyway in addition to a fitting part, the load concerning a shaft can further be reduced. For this reason, the diameter of the shaft can be reduced.
In addition, the positioning of the mold when the workpiece is set by combining the lower mold and the upper mold can be easily performed.

  Further, in any one of the above bending apparatuses, a mold holding means for preventing the lower mold and the upper mold from being opened is provided on an outer side surface portion of the fixing member. Characterize.

When the workpiece is bent, the upper die may be lifted and opened by the action of the pushing force that the workpiece is pushed from the side surface toward the die.
Therefore, according to the present invention, the mold holding means for preventing the opening of the lower mold and the upper mold is provided on the outer side surface portion of the fixing member. Thereby, even if pushing force acts on a metal mold | die, the upper metal mold | die floats up, ie, a metal mold | die can be prevented from opening. Further, it is possible to prevent the mold from being displaced during processing.
Note that the mold holding means is formed of a U-shaped member that forms a through hole having a rectangular cross section in the lower mold, and the upper mold is formed of a protruding member inserted into the through hole. Is.

  According to the bending apparatus of the present invention, a fitting portion is provided on the mating surface of the lower mold and the upper mold even in a small-diameter bending process performed with a radius of curvature equal to or less than the tube diameter. Therefore, the load applied to the shaft is reduced, and the diameter of the shaft can be reduced. If the diameter of the shaft can be reduced, the radius of curvature of the bending surface located around the shaft can be reduced. Thereby, breakage of the shaft and displacement of the mold can be prevented, and small-diameter bending of the workpiece can be easily realized.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 5.
FIG. 1 is an external perspective view of a mold structure (bending apparatus) according to the first embodiment of the present invention. The mold includes a lower mold 1 and an upper mold 2 that overlaps from above the lower mold 1.
As shown in FIG. 2, the lower mold 1 is installed on a turntable 19 that can rotate around a rotation axis extending in the vertical direction.
Each of the lower mold 1 and the upper mold 2 is provided with a protruding portion that protrudes to the opposite mold side, and mating surfaces 27 and 28 are formed on the top surface of each protruding portion. A U-shaped bending surface is formed along the side surface of the protruding portion. The bending surface includes first bending surfaces 22 and 23 that are first straight portions, and a U-turn portion bending surface 24 that is formed continuously from the first bending surfaces 22 and 23. The second bending surfaces 25 and 26 are formed as second straight portions that are formed continuously from the U-turn portion bending surface 24 and extend in the same direction so as to face the bending surfaces 22 and 23. Formed from. That is, the first bending surfaces 22, 23, the U-turn portion bending surface 24, and the second bending surfaces 25, 26 are formed by combining the center surfaces 27, 27 of the lower mold 1 and the upper mold 2. A U-shape is formed so as to surround 28. These processed surfaces have an arcuate cross section so that a tube 15 (see FIG. 2) having a circular cross section as a workpiece can be fixed or abutted. The overall shape of the mold is also U-shaped along the shape of these processed surfaces (see FIG. 1).

On the mating surfaces 27 and 28 of the lower mold 1 and the upper mold 2, through holes 3 and 4 for inserting the shaft 12 (shown by a two-dot chain line in FIG. 1) are formed. On the mating surface 27 of the lower mold 1, a plurality of cylindrical convex portions 7, 8, 9 that are aligned with the through-hole 3 in a line coaxially in the longitudinal direction are integrally formed. The mating surface 28 of the upper mold 2 is formed with a cylindrical concave portion at a position facing the convex portions 7, 8, 9 to which the convex portions 7, 8, 9 can be fitted (not shown). )
In the present embodiment, three convex portions are provided, but one, two, three or more may be provided. The number of convex portions may be determined according to the load of bending stress due to the size of the mold and the radius of curvature of small diameter bending. When only one convex part is provided, the longitudinal end side of the mating surface 27 facing the U-turn part bending surface 24 of the lower mold 1, that is, a position away from the shaft 12 (the convex part 7 in FIG. 1). It is preferable to provide at the position. In the case of providing two or more, it is preferable to provide the position gradually closer to the shaft 12 in order from the position away from the shaft 12, and the required number is provided in order from the position farthest from the shaft 12.

  Fixing members 5 and 6 each having a storage portion having a semicircular cross section for fixing one of the tubes 15 are provided on a part of the first bending surfaces 22 and 23. The longitudinal direction end (end opposite to the U-turn portion bending surface 24) is provided so as to be flush with the end flat surfaces 29, 30 of the mold, and the first bending surfaces 22, 23 A part will be formed (see FIG. 1). A key groove 10 is formed in the entire longitudinal direction of the edge of the side end portion of the fixing member 5, and a key 11 is formed in the entire longitudinal direction of the edge of the side end portion of the fixing member 6 facing the key groove 10. ing. When the lower mold 1 and the upper mold 2 overlap each other, the key 11 is fitted into the key groove 10 (see FIG. 2). The fixing members 5 and 6 may be integrally formed with the mold or may be attached separately. In the case of mounting separately, it is fixed to the mold with, for example, a bolt (not shown).

Further, a mold holding means for holding the mold is formed on the side surfaces in the longitudinal direction of the fixing members 5 and 6. The mold holding means includes a U-shaped member 13 having a U-shaped cross section and a protruding member 14 having a rectangular cross section. The opposite ends of the U-shaped member 13 are fixed to the side surface of the fixing member 5. A rectangular through hole is formed by the inner surface of the U-shaped member 13 and the side surface of the fixing member 5. The projecting member 14 is fixed to the side surface in the longitudinal direction of the fixing member 6 in a state of projecting to the lower mold 1 side.
By configuring the mold holding means in this way, when the lower mold 1 and the upper mold 2 are overlapped, the protruding portion of the protruding member 14 is inserted through the through hole of the U-shaped member 13 ( As shown in FIG. 2, the bonded state of the mold is maintained.
The U-shaped member 13 and the protruding member 14 may be integrally formed with the fixing members 5 and 6 or may be attached separately. When attaching separately, it attaches and fixes by welding joining (not shown) etc., for example.
Further, it is preferable that chamfering is performed on each side of the bottom surface portion (surface on the lower mold 2 side) of the projecting member 14 when insertion of the molds is facilitated.

  One of the tubes 15 is sandwiched between the fixing members 5 and 6 of the lower mold 1 and the upper mold 2 and fixed to the turntable 19 with the lower mold 1 and the upper mold 2 being overlapped by the shaft 12. Is done. The upper part of the shaft 12 is threaded and is fastened and fixed by a nut 17 (see FIG. 2). Because of the small diameter bending process, the shaft 12 having a diameter equal to or smaller than the diameter of the tube 15 is used. The shaft 12 of this embodiment is an example using the same thing as the tube 15.

Next, a bending method of the bending apparatus 50 according to the present embodiment will be described with reference to FIG.
After heating the straight tube 15 which is a workpiece by a predetermined heating device, one of the tubes 15 is fixed to the lower mold 1 and the upper mold 2 as shown in FIG. , 6 to set the tube.

  After the tube setting is performed, as shown in FIG. 2 (b), the tube clamp to which the tube 15 is fixed is performed. That is, the lower mold 1 and the upper mold 2 are overlapped and integrally fixed to the turntable 19 by the shaft 12 and the nut 17, thereby fixing the tube 15. The other of the tubes 15 (the one not fixed to the mold) is in a state in which the semicircular arc-shaped portion on the side surface thereof is in contact with the pressure mold 18. When the molds overlap, the convex parts 7, 8, 9 of the lower mold 1 are fitted into the concave parts (not shown) of the upper mold 2, and the key grooves 10 and the keys 11 of the fixing members 5, 6 are fitted. Are also fitted. Further, the protruding member 14 is inserted into the through hole of the U-shaped member 13.

After the tube clamping is performed, the turntable 19 is rotated by a predetermined bending angle around the rotation axis, and the other end of the tube 15 is gradually bent so as to be wound around the die while being pressed against the pressure die 18. . For example, as shown in FIG. 2C, the tube 15 is bent by 180 degrees, and the other end of the tube 15 is brought into contact with the second bending surfaces 25 and 26, and the process ends.
The tube 15 subjected to the small diameter bending process has a U-shape as shown in FIG. The bent portion is a bent portion having a diameter D of the tube 15 equal to the radius of curvature R, that is, R = 1.0D.

Next, the effect of the bending apparatus 50 concerning this embodiment is demonstrated.
When the rotating table 19 is continuously rotated after the tube clamping and bending is started, the rotational force is transmitted from the rotating table 19 to the lower mold 1 and further transmitted from the lower mold 1 to the upper mold 2. At this time, rotational force, that is, bending stress acts on the shaft 12. Conventionally, the bending stress applied only to the shaft 12 is also applied to the convex portions 7, 8, 9 formed on the mating surface 27, and the bending stress is accordingly increased to the convex portions 7, 8, 9. And the load applied to the shaft 12 is reduced. Thereby, it is possible to prevent the shaft 12 from being distorted or broken due to a bending stress with a simple structure in which a cylindrical uneven portion is provided in the mold. If the load on the shaft 12 is reduced, small-diameter bending using a shaft diameter equal to or less than the diameter of the tube 15 can be performed. In addition, since the cylindrical concavo-convex portion prevents the mold from being displaced in the horizontal direction during processing, the mold can be prevented from being damaged.
Note that it is preferable to increase the number of the uneven portions as the diameter of the shaft 12 becomes smaller. This is because the force applied to the small-diameter shaft 12 can be dispersed by the number of the concavo-convex portions, and the effect of preventing the shaft 12 from being damaged is enhanced.
Further, when there is one uneven portion, the force applied to the shaft 12 is dispersed as the position is farther from the shaft 12.
In the present embodiment, the cylindrical concavo-convex portion is used, but the same effect can be obtained even in a triangular or rectangular shape.
Furthermore, the uneven portion may be a ring-shaped uneven portion (not shown) such as a donut shape, and the load applied to the shaft can be reduced similarly to the cylindrical shape. If it is a ring-shaped convex part, the outer peripheral part circle | round | yen except the center part circle | round | yen will be formed in convex shape. Since this center circle is the same surface as the surrounding surface other than the convex portion, it is concave compared to the outer circumference circle. On the other hand, the concave portion is formed with a concave groove in the outer peripheral portion excluding its center circle. Since the center circle is the same surface as the surrounding surface other than the groove portion, it is formed in a convex shape from the groove portion.
Therefore, since the fitting of the concavo-convex part of the center circle and the fitting of the concavo-convex part at the outer peripheral part circle are performed, the effect of preventing the deviation of the mold can be further enhanced by the fitting of these two places.
The concavo-convex part of the present embodiment shows an example in which a convex part is formed on the lower mold 1 and a concave part is formed on the upper mold 2, but the same effect can be obtained even if these are formed in reverse. Play.

  Further, in the present embodiment, the key groove 10 and the key 11 are formed in the entire longitudinal direction of the edges of the side end portions of the fixing members 5 and 6, whereby the bending stress described above is applied to the key groove 10 and the key 11. Is also dispersed, and the effect of preventing the mold from shifting is also increased. As a result, the effect of preventing the shaft 12 and the mold from slipping further increases, so that the diameter of the shaft 12 can be reduced and more stable small-diameter bending can be performed.

By the way, during bending, as shown by the arrow 20 in FIG. Since the strength of the shaft 12 decreases as the diameter of the shaft 12 is reduced, the shaft 12 cannot withstand this pushing force, and the upper mold 2 may fall in the direction of the arrow 21 to open the mold.
Therefore, in this embodiment, in order to prevent the mold from opening, a U-shaped member 13 that forms a rectangular through hole and a protruding member 14 that can be inserted into the through hole are provided. The protruding member 14 is fitted through the through hole of the U-shaped member 13 (see FIG. 2B). For this reason, even if it is a case where the upper metal mold | die 2 tends to fall in the direction of the arrow 21 with pushing force, the opening of a metal mold | die can be prevented without the protrusion member 14 falling out. Thereby, the diameter of the shaft 12 can be further reduced, and a more stable small-diameter bending process can be performed.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 5 shows an external perspective view of a mold structure (bending apparatus) according to the second embodiment of the present invention.
Since the basic configuration of the mold is the same as that of the first embodiment, the description thereof is omitted.
In the first embodiment described above, a cylindrical uneven portion is provided in order to disperse the bending stress applied to the shaft 12, but in this embodiment, the key 31 and the key groove 32 are used instead of the cylindrical uneven portion. Is different in that it is formed in a cross shape.

The cross-shaped key 31 is integrally formed at the central portion on the mating surface 27 of the lower mold 1 with one end extending linearly from the vicinity of the through hole 3 to the same plane as the end plane 29 of the lower mold 2. Has been. Similarly, in the central portion on the mating surface 27, it extends linearly from one side end portion in the lateral direction of the mold to the other side end portion, and is integrally formed perpendicular to the longitudinal direction key to form a cross shape. It is what.
A cross-shaped key groove 32 into which the key 31 is fitted is formed on the mating surface 28 of the upper mold 2 at a position facing the key 31 (see FIG. 5).

Next, the effect of the bending apparatus 50 concerning this embodiment is demonstrated.
Similarly to the first embodiment, tube setting and tube clamping are performed (see FIG. 2).
When the rotating table 19 is continuously rotated after the tube clamping and bending is started, the rotational force is transmitted from the rotating table 19 to the lower mold 1 and further transmitted from the lower mold 1 to the upper mold 2. At this time, the bending stress of the tube 15 acts on the shaft 12 and the mold. In the present embodiment, since the cross-shaped key 31 and key groove 32 are formed on the mating surfaces 27 and 28, the bending stress applied to the shaft 12 is distributed to the key 31. Since the key 31 is continuously formed in the longitudinal direction and the lateral direction of the mold, the bending stress is uniformly distributed on the mating surface 27, and the load applied to the shaft 12 can be reduced. it can. As a result, the straight key 31 and the key groove 32 are provided in the mold, and the shaft 12 is prevented from being damaged due to bending stress, such as distortion or breakage. The shaft diameter is equal to or smaller than the tube diameter. The small-diameter bending process can be performed. Furthermore, since the shift of the mold in the lateral direction during processing is prevented, damage to the mold can also be prevented.

1 is an external perspective view showing a mold structure (bending apparatus) according to an embodiment of the present invention. (A) is a front view which shows the tube setting to the metal mold | die concerning one Embodiment of this invention. (B) is a front view which shows the tube clamp state which fixes a tube. (C) is a front view which shows the state by which the tube was bent 180 degree | times. It is a top view which shows the tube shape by which the small diameter bending process concerning one Embodiment of this invention was carried out. It is a front view which shows the state which the opening of the metal mold | die at the time of a bending process generate | occur | produced. 1 is an external perspective view showing a mold structure (bending apparatus) according to an embodiment of the present invention. It is the schematic which shows a tube element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lower die 2 Upper die 3, 4 Through hole 5, 6 Fixing member 7, 8, 9 Protrusion part 10 Key groove 11 Key 12 Shaft 13 U-shaped member (die holding means)
14 Protruding member (mold holding means)
15 Tubing 16 Tubing Element 17 Nut 18 Pressure Die 19 Turntable 22, 23 First Bending Surface 24 U-Turn Bending Surface 25, 26 Second Bending Surface 27, 28 Matching Surface 29, 30 End of Mold Plane 31 key (cross shape)
32 Keyway (Cross shape)
50 Bending machine

Claims (7)

A turntable capable of rotating around the rotation axis;
A lower mold fixed on the turntable;
An upper mold overlapping the lower mold;
A shaft for integrally fixing the lower mold and the upper mold to the turntable;
When the lower mold and the upper mold are overlapped, the workpiece is brought into contact with a bending surface positioned around the shaft, and the workpiece is rotated by rotating the turntable around the rotation axis. In bending equipment that performs bending
A bending apparatus characterized in that a fitting portion is provided on a mating surface between the lower mold and the upper mold. The bending surface includes a first straight portion, a U-turn portion formed continuously from the first straight portion, and a second facing the first straight portion continuously from the U-turn portion. It is a U-shape formed by the straight part of
A through hole into which the shaft is inserted is provided in the vicinity of the inner end of the U-turn part,
2. The bending apparatus according to claim 1, wherein the fitting portion is formed between the first straight portion and the second straight portion at a position apart from the through hole. .   3. The bending apparatus according to claim 1, wherein a plurality of the fitting portions are arranged and arranged between the first straight portion and the second straight portion. 4.   4. The bending apparatus according to claim 1, wherein the fitting portion is a convex portion and a concave portion, the convex portion is cylindrical, and the concave portion is a cylindrical hole. .   The bending apparatus according to claim 1, wherein the fitting portion is a key and a key groove. The bending surface having the first straight portion is provided with a fixing member for fixing the workpiece.
6. A second key and a second key groove are provided in an outer end portion of the fixing member in a direction along the first straight line portion. Bending machine.   The bending according to any one of claims 1 to 6, wherein a mold holding means for preventing the lower mold and the upper mold from opening is provided on an outer side surface portion of the fixing member. Processing equipment.

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