Bending Equipment

Abstract

To perform processing for forming a three-dimensional curved face up to an end part of a workpiece, in a bending processor which employs a three-point bending technique.SOLUTION: A bending processor 1 comprises: a pair of dies 2 arranged below a transport route T of a workpiece W while separating from each other in a transport direction of the workpiece W; a punch 3 arranged between the pair of dies 2, and above the transport route T; and a backup plate 4 supported by the pair of dies 2, and interposed between the workpiece W which passes the transport route T and the pair of dies 2. The backup plate 4 is composed of divided backup plates in which a plurality of divided plate units 41 are aligned in a width direction of the workpiece W which intersects with the transport direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a bending device that performs bending on a plate-shaped workpiece. [Background technology]

[0002] A bending apparatus using an upper die (punch) and a lower die (die) is known as an apparatus for bending a plate-shaped workpiece. In this bending apparatus, the upper die is pressed against a workpiece supported by the lower die, thereby plastically deforming the workpiece. Patent Document 1 discloses a bending apparatus in which a gas spring is disposed in a groove of the lower die, which has a groove for receiving the upper die during bending, to provide an upward repulsive force to the workpiece pressed downward by the upper die. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 143302 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional bending equipment uses a three-point bending technique in which the lower two points of a workpiece are supported by a lower die, and the upper die presses a point midway between the two lower points. For this reason, it is possible to bend a workpiece in one direction (single contour machining), but it is difficult to apply a three-dimensional curved surface to a workpiece (double contour machining) with conventional bending equipment.

[0005] An object of the present invention is to provide a bending apparatus that employs a three-point bending technique and is capable of performing processing to provide a three-dimensional curved surface up to the end of a workpiece. [Means for solving the problem]

[0006] A bending apparatus according to one aspect of the present invention comprises a pair of dies arranged below a workpiece transport path and spaced apart from each other in the transport direction of the workpiece, a punch arranged between the pair of dies and above the transport path, and a backup plate supported by the pair of dies and interposed between the workpiece passing through the transport path and the pair of dies, wherein the backup plate includes a portion in which a plurality of divided pieces are arranged in the width direction of the workpiece perpendicular to the transport direction.

[0007] According to this bending device, a pair of dies and a punch bend the workpiece by a three-point bending method. A backup plate is interposed between the workpiece and the pair of dies. The backup plate is deformed together with the workpiece when the workpiece is pressed by the punch. For this reason, even if the workpiece has a plate thickness different in the XY direction, the workpiece is prevented from bending (kinking), and the end of the workpiece can be bent with high precision. Furthermore, the backup plate includes a plurality of divided pieces arranged in the width direction. That is, it is possible to make the amount of deformation different for each divided piece. Therefore, the workpiece can be bent not only in the direction along the conveying path, but also in the width direction in which the divided pieces are arranged. That is, the workpiece can be bent three-dimensionally, particularly up to the end of the workpiece. Effect of the Invention

[0008] According to the present invention, it is possible to provide a bending apparatus that employs a three-point bending technique and is capable of performing three-dimensional bending up to the end of a workpiece. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing a schematic overall configuration of a bending apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing one bending unit of the bending apparatus. [Diagram 3] FIG. 3 is a block diagram showing a configuration of the bending device. [Figure 4] 4(A) and (B) are side cross-sectional views showing the state in which the bending device is bending a workpiece in the Y direction. [Diagram 5] 5(A) and (B) are cross-sectional side views taken along line VV in FIG. 4(A) showing the state in which the bending device is bending a workpiece in the X direction. [Figure 6] 6(A) is a plan view of a unit plate, FIG. 6(B) is a top view of a cover, and FIG. 6(C) is a cutaway side view of a main part of the cover. [Figure 7] FIG. 7(A) is an exploded perspective view of a divided plate unit, and FIG. 7(B) is a perspective view of the divided plate unit after assembly. [Figure 8] FIG. 8 is a perspective view showing a state in which the divided plate unit is assembled to the die. [Figure 9] FIG. 9 is a perspective view showing a state in which an end portion of a workpiece is bent by the bending device. [Figure 10] 10(A) and (B) are schematic diagrams showing examples of use of a die and a punch. [Figure 11] 11(A) and (B) are schematic diagrams showing examples of use of a die and a punch. [Figure 12] 12(A) and (B) are schematic diagrams showing examples of use of a die and a punch. [Figure 13] FIG. 13(A) is a top view of a backup plate having an opening, and FIG. 13(B) is a cross-sectional view taken along line XIIIB-XIIIB of FIG. 13(A). [Figure 14] FIG. 14 is a plan view of a slit-type backup plate. [Figure 15] 15(A) and (B) are schematic side views for explaining modified examples of the backup plate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The bending apparatus according to the present invention is used for performing not only two-dimensional bending but also three-dimensional bending on plate-shaped workpieces that undergo plastic deformation, such as metal plates, metal plywood, composite plates of metal and resin, etc. For example, the bending apparatus can be suitably used for bending long and wide plate-shaped workpieces, such as outer panels of aircraft and railway vehicles and outer panels of various storage tanks.

[0011] [Overall configuration of bending equipment] Fig. 1 is a perspective view showing a schematic overall configuration of a bending apparatus 1 according to an embodiment of the present invention. The bending apparatus 1 is an apparatus for performing three-point bending on a plate-shaped workpiece W that is intermittently fed along a conveying path T, and includes a pair of dies 2, a punch 3, and a backup plate 4. In Fig. 1 and other drawings, the conveying direction of the workpiece W is shown as the Y direction, the width direction of the workpiece W perpendicular to the conveying direction is shown as the X direction, and the up-down direction perpendicular to the plane of the workpiece W is shown as the Z direction.

[0012] The pair of dies 2 are disposed below the transport path T, and are disposed at a predetermined distance from each other in the transport direction of the workpiece W. That is, the pair of dies 2 is composed of a first die 2A disposed on the upstream side of the transport direction and a second die 2B disposed on the downstream side. The first die 2A and the second die 2B function as lower dies that support two lower points of the workpiece W in the three-point bending. In this embodiment, the pair of dies 2 support the backup plate 4 carrying the workpiece W at two points.

[0013] The pair of dies 2 extend in the X direction and are disposed between a pair of frame members 11 arranged parallel to each other. The pair of dies 2 and the frame members 11 are placed on a flat base 12. The first die 2A and the second die 2B are movable in the Y direction on the base 12 by a die-to-die adjustment mechanism M1. A specific example of the die-to-die adjustment mechanism M1 will be described later with reference to FIG. 2.

[0014] The punch 3 is disposed between the pair of dies 2 and above the transport path T. The punch 3 is movable in the vertical direction and serves as an upper die that presses an upper point of the workpiece W in three-point bending. The punch 3 is attached to a punch unit 30. The punch unit 30 includes a movable frame 13 that can be raised and lowered relative to a base 12, and the punch 3 is attached to the lower surface of the movable frame 13. The punch 3 can be lowered and raised relative to the movable frame 13 by a punch drive mechanism M2. When lowered, the punch 3 comes into contact with and presses the workpiece W, causing plastic deformation of the workpiece W.

[0015] The backup plate 4 is supported by the pair of dies 2 at one end and the other end in the transport direction, and is interposed between the workpiece W passing through the transport path T and the pair of dies 2. In other words, the backup plate 4 extends across the first die 2A and the second die 2B so as to fill the gap between the first die 2A and the second die 2B. The upper surface of the backup plate 4 abuts against the lower surface of the workpiece W to support the workpiece W. When a downward pressing force is applied from the punch 3 to the workpiece W, the backup plate 4 is curved downward together with the workpiece W. However, the deformation of the backup plate 4 is within the range of elastic deformation.

[0016] The pair of dies 2, the punch 3 and the backup plate 4 are structured to be split in the X direction. The first die 2A on the upstream side in the conveying direction of the workpiece W is made up of a group of a plurality of first die pieces 21A arranged in parallel in the X direction. The second die 2B on the downstream side is made up of a group of a plurality of second die pieces 21B arranged in parallel in the X direction. A pair of split dies 21 is constituted by one first die piece 21A and one second die piece 21B facing each other in the Y direction. The pair of dies 2 is made up of a group of a pair of split dies 21 arranged in parallel in the X direction.

[0017] The punch 3 is composed of a group of split punches 31 arranged corresponding to each of the pair of split dies 21. The multiple split punches 31 constituting the group are arranged in a row in the X direction. The split punches 31 may be arranged in multiple rows in the X direction, or may be arranged in a zigzag pattern.

[0018] The backup plate 4 has a structure including a portion in which a plurality of divided pieces are arranged in the width direction (X direction) of the workpiece W. The plurality of divided pieces are specifically composed of a plurality of divided plate units 41 separated from one another. The divided plate unit 41 has a rectangular shape that is long in the transport direction (Y direction) of the workpiece W when viewed from above. The X-direction width of the divided plate unit 41 is approximately the same as the X-direction width of the divided die 21. The backup plate 4 is composed of an array of a plurality of such divided plate units 41 arranged in parallel in the X direction.

[0019] Each divided plate unit 41 is supported by a pair of divided dies 21. In other words, a pair of dies 2 and punches 3 are provided separately in correspondence with each divided plate unit 41. That is, one divided plate unit 41 is supported by a pair of divided dies 21 arranged correspondingly thereto, and one divided punch 31 is arranged for the combination of these, thereby forming one bending unit 10 (FIG. 2).

[0020] It is sufficient that at least one of the pair of dies 2 or punch 3 is of a split type corresponding to the split plate unit 41. For example, the pair of dies 2 may be an arrangement of a pair of split dies 21 as shown in Fig. 1, while a non-split integral punch is used as the punch 3. Conversely, the first die 2A and the second die 2B of the pair of dies 2 may each be a non-split integral die, and the punch 3 may be an arrangement of split punches 31.

[0021] [Configuration of one bending unit] Fig. 2 is a cross-sectional view showing one bending unit 10 of the bending apparatus 1. The bending unit 10 is composed of one divided die 21, one divided punch 31, and one divided plate unit 41. Fig. 2 shows a state in which a workpiece W to be bent while being intermittently fed along a conveying path T is placed on the divided plate unit 41.

[0022] The first die piece 21A and the second die piece 21B of the pair of split dies 21 can move toward or away from each other in the Y direction. That is, the die spacing d between the first die piece 21A (one of the pair of split dies) and the second die piece 21B (the other of the pair of split dies) can be adjusted for each split die 21. The die spacing d is changed depending on the size of the workpiece W to be processed, the shape of the bend, etc.

[0023] The first die piece 21A is mounted on the upper surface of a first mover 22A that is movable in the Y direction. Similarly, the second die piece 21B is mounted on the upper surface of a second mover 22B that is movable in the Y direction. The first die piece 21A and the second die piece 21B move toward or away from each other as the first mover 22A and the second mover 22B move, while always maintaining a symmetrical relationship across the pressing axis C along which the split punch 31 rises and falls.

[0024] The first mover 22A is provided with a first screw hole 221 extending in the Y direction. Similarly, the second mover 22B is provided with a second screw hole 222 extending in the Y direction. A ball screw 23 extending in the Y direction is inserted through the first screw hole 221 and the second screw hole 222. A first screw portion 231 that screws into the first screw hole 221 is formed on the first die piece 21A side of the ball screw 23, and a second screw portion 232 that screws into the second screw hole 222 is formed on the second die piece 21B side. The first screw portion 231 and the second screw portion 232 are threaded in opposite directions.

[0025] One end and the other end of the ball screw 23 are rotatably supported by a pair of frame members 11. An output shaft of a die drive motor 24 is connected to one end of the ball screw 23. The die drive motor 24 generates a driving force for rotating the ball screw 23 forward or backward around its axis. When the ball screw 23 rotates, the first mover 22A and the second mover 22B screwed to the ball screw move in different directions. For example, when the ball screw 23 rotates forward, the first mover 22A and the second mover 22B move closer to each other, and the first die piece 21A and the second die piece 21B move closer to each other. On the other hand, when the ball screw 23 rotates backward, the first die piece 21A and the second die piece 21B move away from each other.

[0026] The driving mode of the pair of split dies 21 shown here is just an example. For example, the first die piece 21A and the first mover 22A having a through hole with a larger diameter than the ball screw 23, and the similar second die piece 21B and the second mover 22B may be arranged side by side. Also, instead of the die drive motor 24, a hydraulic system such as a hydraulic cylinder may be used as the driving source of the pair of split dies 21.

[0027] The split punch 31 can move in the vertical direction (Z direction). The split punch 31 is provided with a punch drive motor 32 that moves the split punch 31 forward and backward individually relative to the workpiece W. A screw shaft 33 extending in the Z direction is connected to the punch drive motor 32. The punch drive motor 32 is provided with a drive mechanism that raises and lowers the screw shaft 33. The split punch 31 has a screw hole 311 that opens upward, and the lower end portion of the screw shaft 33 is screwed into this screw hole 311. When the punch drive motor 32 raises and lowers the screw shaft 33, the split punch 31 also rises and lowers. The punch drive motor 32 lowers the screw shaft 33 so that the lower end of the split punch 31 is pressed against the workpiece W, thereby performing bending processing on the workpiece W. Note that instead of the punch drive motor 32, a hydraulic cylinder or the like that raises and lowers a rod connected to the punch 3 may be used.

[0028] The divided plate unit 41 includes a plate stack 42 and a cover 43 that is placed on the plate stack 42 from above. The plate stack 42 is a stack of multiple thin unit plates 4P stacked vertically. The cover 43 is also a thin plate that is placed on the plate stack 42.

[0029] In order to ensure the strength of the divided plate unit 41 that functions as a part of the backup plate 4, it is necessary to provide it with an appropriate thickness. However, if the divided plate unit 41 is configured with a single thick plate, the range in which it can elastically deform is limited. In contrast, by using a stacked structure of unit plates 4P, the elastic deformation range of the divided plate unit 41 can be increased. Therefore, even if the divided punch 31 presses the workpiece W so as to plastically deform it, the range in which the divided plate unit 41 can only elastically deform can be increased. Note that a single thick plate may be used instead of the plate stack 42.

[0030] The X-direction width of the plate stack 42 (unit plate 4P) and the cover 43 is approximately the same as that of the first die piece 21A and the second die piece 21B. The Y-direction width of the plate stack 42 has a length from the outer end face (the end face on the frame member 11 side) of the first die piece 21A to the outer end face of the second die piece 21B. The Y-direction upstream side of the plate stack 42 is supported by the first die piece 21A, and the Y-direction downstream side is supported by the second die piece 21B. The Y-direction width of the cover 43 is longer than that of the plate stack 42, and has a length that bridges a pair of frame members 11.

[0031] [Electrical configuration and operation of bending device] Fig. 3 is a block diagram showing the electrical configuration of the bending apparatus 1. The bending apparatus 1 includes a work transport mechanism 51 (not shown in Figs. 1 and 2), the above-mentioned die drive motor 24 and punch drive motor 32, a sensor 6 for performing various sensing operations, and a control device 5.

[0032] The workpiece transport mechanism 51 is a mechanism that intermittently transports the workpiece W in a predetermined transport direction (Y direction). In the bending device 1, a routine is repeated in which the punch 3 (split punch 31) presses a specific position of the workpiece W to perform a preceding bending process, and when the preceding bending process is completed, the subsequent bending process is performed at a subsequent position following the specific position. The workpiece transport mechanism 51 executes a transport operation in which the workpiece W is stopped at the specific position, and when the preceding bending process is completed, the workpiece W is sent so that the subsequent position is located directly below the punch 3. As the workpiece transport mechanism 51, for example, a conveyor capable of feeding the workpiece W in sequence, or a robot arm can be applied.

[0033] The sensor 6 is a sensor that acquires information for controlling the bending apparatus 1. For example, the sensor 6 is a sensor that measures the bending shape and temperature of the workpiece W, a sensor that detects the feed position of the workpiece W, and an electrical or optical sensor that detects the pressure applied to the backup plate 4.

[0034] The control device 5 controls the work transport mechanism 51, the die drive motor 24, the punch drive motor 32, and other mechanisms not shown, to comprehensively control the operation of the bending apparatus 1. That is, the control device 5 drives the work transport mechanism 51 to control the intermittent feeding operation of the work W, drives the die drive motor 24 to control the moving operation of the die 2, and drives the punch drive motor 32 to control the lifting and lowering operation of the punch 3. The control device 5 also controls the bending operation of the work W based on the sensing results of the sensor 6.

[0035] 4(A) and (B) are side cross-sectional views showing the state of bending the workpiece W in the Y direction by the bending device 1 (bending unit 10). Under the control of the control device 5, the workpiece transport mechanism 51 intermittently transports the plate-shaped workpiece W along the transport path T. As shown in FIG. 4(A), the punch drive motor 32 (FIG. 2) lowers the punch 3 (split punch 31) to a predetermined position when the workpiece W stops. Then, the punch unit 30 is pressed downward by a press device (not shown), so that the punch 3 applies a pressing force from the upper surface of the workpiece W to bend the workpiece W. At this time, the backup plate 4 (split plate unit 41) supporting the workpiece W is curved downward together with the workpiece W, and applies a reaction force to the workpiece W. Note that, when a mechanism with a high thrust such as a hydraulic cylinder is applied as the drive mechanism for the punch 3 (split punch 31), bending can be performed by the thrust of the drive mechanism without relying on the press device.

[0036] 4(B) shows the state in which the punch 3 has been raised after completing a predetermined pressing routine. The pressing causes the workpiece W to plastically deform into a downwardly convex curved shape. Meanwhile, the backup plate 4 only undergoes elastic deformation, so it returns to its original horizontal shape. The presence of the backup plate 4 makes it possible to prevent the workpiece W from kinking, and also makes it possible to bend the workpiece W in the Y direction up to the edge of the workpiece W in the transport direction.

[0037] 5(A) and (B) are schematic diagrams showing a cross section along line VV in FIG. 4(A), and are side cross-sectional views showing the state in which the bending device 1 is bending the workpiece W in the X direction. As shown in FIG. 5(A), the lower surface of the workpiece W is supported by a group of divided plate units 41 arranged in the X direction, and is further supported by divided dies 21 arranged corresponding to each divided plate unit 41. In addition, divided punches 31 are arranged on the upper surface side of the workpiece W corresponding to each divided plate unit 41. Therefore, it is possible to perform bending in the X direction on the workpiece W with a resolution corresponding to the arrangement pitch of the divided plate units 41.

[0038] 5(B) shows a state in which some of the divided punches 31 are lowered and bending along the X direction is actually being performed on the workpiece W. Specifically, among the group of 12 divided punches 31, divided punches 31A to 31D located in the central region in the X direction are lowered to press the workpiece W downward. This shows an example in which the divided punches 31B and 31C at the very center are lowered to a large extent, while the divided punches 31A and 31D located on both sides of these are lowered to a relatively small extent.

[0039] The portions of the workpiece W pressed down by the split punches 31A-31D are curved downward. At this time, the split plate units 41A-41D supporting the workpiece W corresponding to the split punches 31A-31D also bend downward according to the amount of pressing of the split punches 31A-31D, exerting a reaction force on the workpiece W. When the split punches 31A-31D rise, the split plate units 41A-41D elastically restore, while the workpiece W is plastically deformed and bent in the X direction.

[0040] According to the present embodiment described above, the bending apparatus 1 that performs bending on the workpiece W by the three-point bending technique is configured to support the workpiece W with the backup plate 4, and to deform the backup plate 4 together with the workpiece W when the workpiece W is pressed by the punch 3. This prevents the workpiece from kinking, and allows the end of the workpiece W to be bent with high precision.

[0041] Furthermore, the backup plate 4 is composed of a group of multiple divided plate units 41 arranged in the X direction corresponding to the width direction of the workpiece W, and each of these divided plate units 41 is supported by a pair of divided dies 21. Therefore, the divided plate units 41 can be deformed independently in the Y direction along the Y conveying path, and can also be deformed independently in the X direction corresponding to the width direction of the workpiece W. In addition, since the divided punches 31 are arranged corresponding to each divided plate unit 41, it is possible to make the amount of deformation different for each divided plate unit 41. Therefore, the workpiece W can be bent not only in the Y direction but also in the X direction. In other words, three-dimensional bending can be freely performed on the center and end parts of the workpiece W.

[0042] The bending device 1 also includes a die gap adjustment mechanism M1 including a ball screw 23 and a die drive motor 24 that individually adjusts the die gap d between the first die piece 21A and the second die piece 21B of the pair of split dies 21. This allows the bending shape of the workpiece W to be changed for each split die 21 according to the die gap d. This makes it possible to perform a variety of three-dimensional bending processes on the workpiece W.

[0043] Furthermore, the bending apparatus 1 includes a punch drive mechanism M2 including a punch drive motor 32 that moves each of the divided punches 31 individually forward and backward relative to the workpiece W. This makes it possible to adjust the degree of pressure applied to the workpiece W for each divided punch 31. This allows the workpiece W to be bent in the X direction more precisely.

[0044] [Backup plate details] Next, a detailed structure of the divided plate unit 41 constituting the backup plate 4 will be described. As described above, the divided plate unit 41 includes a plate stack 42 which is a stack of unit plates 4P, and a cover 43 which is placed on the plate stack 42 from above. Fig. 6(A) is a plan view of one unit plate 4P, Fig. 6(B) is a top view of the cover 43, and Fig. 6(C) is a cutaway side view of a main part of the cover 43. Fig. 7(A) is an exploded perspective view of the divided plate unit 41, and Fig. 7(B) is a perspective view of the divided plate unit 41 after assembly.

[0045] The unit plates 4P are made of rectangular flat plates that are long in the conveying direction (Y direction) of the work W. The material of the unit plates 4P is preferably a metal material with a relatively large elastic deformation area, for example, spring steel. The plate stack 42 can be formed by stacking several to several tens of unit plates 4P. It is preferable that no special adhesive treatment is performed between the layers of the stacked unit plates 4P in order to improve the bending property of the plate stack 42. The X-direction width of the unit plates 4P near the top layer of the plate stack 42 is narrower than the X-direction width of the unit plates 4P in the lower layers because the cover 43 including the X-direction bent parts (X-direction tab 433 and X-direction center tab 434 described later) is placed on top of the plate stack 42.

[0046] The cover 43 functions to prevent the stacking state of the unit plates 4P constituting the plate stack 42 from being disturbed. The cover 43 includes a top plate 431 and a plurality of tabs that are bent and formed so as to hang down from the top plate 431. The cover 43 can be made of the same material as the unit plates 4P, and is preferably made of, for example, spring steel.

[0047] The top plate 431 is a rectangular flat plate long in the Y direction. The size of the top plate 431 in the X direction is approximately the same as that of the unit plate 4P (plate stack 42), but the size in the Y direction is longer than that of the unit plate 4P. This is because the unit plate 4P is spanned across a pair of dividing dies 21, whereas the top plate 431 is spanned across a pair of frame members 11 disposed outside the pair of dividing dies 21. When the cover 43 is fitted onto the plate stack 42 from above, the top plate 431 comes into contact with the unit plate 4P of the top layer of the plate stack 42 from above. In a modified example in which the cover 43 is disposed so as to span across a pair of dividing dies 21 instead of a pair of frame members 11, the length of the unit plate 4P is approximately the same as that of the top plate 431.

[0048] The cover 43 of this embodiment includes a Y-direction tab 432, an X-direction tab 433, and an X-direction central tab 434 as the multiple tabs, and an end plate 436. The end plate 436 is a portion bent downward at a right angle from each of both Y-direction end edges of the top plate 431. The Z-direction width (vertical width) of the end plate 436 is approximately equal to the total Z-direction width of the plate stack 42 and the first die piece 21A (or the second die piece 21B). The Z-direction width of the end plate 436 can be set arbitrarily depending on the size, shape, etc. of the frame member 11.

[0049] The Y-direction tabs 432 are formed by bending parts of the top plate 431 downward at a right angle in regions close to the pair of end plates 436 of the top plate 431. Each of the Y-direction tabs 432 is formed by punching a U-shaped slit in the top plate 431, and bending the bent pieces created by the punching, downward along a bending line extending in the X-direction. The distance between the pair of Y-direction tabs 432 is approximately equal to the Y-direction width of the plate stack 42. Furthermore, the Z-direction width of each Y-direction tab 432 is approximately equal to the Z-direction width of the plate stack 42. Instead of the illustrated example, the Z-direction width of the Y-direction tab 432 may be made larger than the Z-direction width of the plate stack 42. Furthermore, the pair of Y-direction tabs 432 may be arranged in a manner that does not face each other. Furthermore, if the end plates 436 can be used instead, the pair of Y-direction tabs 432 may be omitted.

[0050] The X-direction tabs 433 are formed by bending the bent pieces protruding from both ends of the top plate 431 in the X direction at a right angle downward. In this embodiment, an example is shown in which four X-direction tabs 433 are arranged on one side edge and the other side edge of the top plate 431 in the X direction within the width range of the pair of Y-direction tabs 432. Each of the four X-direction tabs 433 faces each other in the X direction. The distance between the pair of facing X-direction tabs 433 is approximately equal to the X-direction width of the plate stack 42. In addition, the Z-direction width of each X-direction tab 433 is set longer than the Z-direction width of the plate stack 42. It is sufficient that at least one X-direction tab 433 is arranged on one side edge and the other side edge of the top plate 431 in the X direction, and they do not have to face each other. Furthermore, it is sufficient that at least one of the multiple X-direction tabs 433 has a Z-direction width that covers the split die 21 at the arrangement position of the split die 21.

[0051] The X-direction central tab 434 is also formed by bending the bent pieces protruding from both ends of the top plate 431 in the X direction at a right angle downward. The X-direction central tab 434 is disposed between two X-direction tabs 433 near the center on one side edge and the other side edge of the top plate 431 in the X direction. The one and the other X-direction central tabs 434 face each other in the X direction. The distance between the pair of X-direction central tabs 434 is approximately equal to the X-direction width of the plate stack 42. The Z-direction width of each X-direction central tab 434 is approximately equal to the Z-direction width of the plate stack 42. However, since the X-direction restraint of the plate stack 42 is achieved by the X-direction tab 433, the Z-direction width of the X-direction central tab 434 may be different from the Z-direction width of the plate stack 42.

[0052] A plurality of slits 435 extending in the Z direction are provided at equal pitches in the X-direction central tab 434. Due to these plurality of slits 435, the X-direction central tab 434 has a configuration in which a plurality of rectangular hanging pieces are lined up in the Y direction.

[0053] As shown in FIG. 7B, the cover 43 is placed on the plate stack 42 from above so as to embrace the plate stack 42 at the Y-direction tab 432, the X-direction tab 433, and the X-direction central tab 434. Therefore, the side surfaces of the plate stack 42 are restrained by the above-mentioned tabs 432, 433, and 434. Therefore, even if the plate stack 42 is curved and deformed following the workpiece W, it is possible to prevent the stacking state of the unit plates 4P from being disturbed. In addition, since the X-direction central tab 434 is formed by bending the bending piece, a curved surface portion 434R is formed at the bending point. The existence of this curved surface portion 434R makes it possible to prevent the corners of the cover 43 from scratching the workpiece W.

[0054] Specifically, the plate stack 42 has a rectangular parallelepiped shape elongated in the Y direction (transport direction), and has a first side surface 4X that is a side surface extending along the transport direction, and a second side surface 4Y that is perpendicular to the first side surface 4X. The X-direction tab 433 and the X-direction center tab 434 abut against the first side surface 4X. The plate stack 42 is restrained in the X direction by the X-direction tab 433 and the X-direction center tab 434, and interlayer slip in the X direction between the unit plates 4P due to the lateral load generated during bending is restricted. The Y-direction tabs 432 abut against the second side surface 4Y. The plate stack 42 is restrained in the Y direction by the Y-direction tab 432, and interlayer slip in the Y direction between the unit plates 4P during bending is restricted. Therefore, interlayer slip in the XY directions between the unit plates 4P can be reliably restricted.

[0055] 8 is a perspective view showing a state in which the split plate unit 41 is assembled to the split die 21 (first die piece 21A). The end plates 436 of the cover 43 abut against the outer surfaces of the frame members 11. In other words, the cover 43 is fitted onto the pair of frame members 11 so that the pair of end plates 436 fit into the outer surfaces of the pair of frame members 11, respectively.

[0056] The plate stack 42 is placed on the first die piece 21A (and the second die piece 21B). The pair of X-direction tabs 433 near the end plate 436 are fitted in such a way as to sandwich the first die piece 21A. In other words, one X-direction tab 433 is inserted into the gap between two adjacent first die pieces 21A. That is, the X-direction tab 433 restrains the first side surface 4X of the plate stack 42 at its upper portion, while fitting into the first die piece 21A at its lower portion. This brings the split plate unit 41 into a state in which it is engaged with the pair of split dies 21.

[0057] FIG. 9 is a perspective view showing the bending of the Y-direction end of the workpiece W by the bending device 1. Here, three split punches 31A, 31B, and 31C among the multiple split punches 31 are lowered to press the Y-direction end of the workpiece W. The pressing causes the workpiece W to be plastically deformed into a downwardly convex curved surface. Furthermore, the split plate units 41A, 41B, and 41C arranged corresponding to the split punches 31A, 31B, and 31C are also elastically deformed into a downwardly convex curved surface. The split plate unit 41D adjacent to the split plate unit 41A and not directly pressed down by the split punch 31 is also slightly elastically deformed by being pressed by the deformed workpiece W. On the other hand, the split plate unit 41E adjacent to the split plate unit 41D is not elastically deformed.

[0058] Here, the curved surface applied to the workpiece W includes the individual Y-direction curvatures of the divided plate units 41A, 41B, and 41C, and the X-direction curvatures due to the curvature deformation of only the divided plate units 41A, 41B, and 41C and the divided plate unit 41D adjacent to this group among the divided plate units 41. First, if the backup plate 4 is not used, it is difficult to bend the Y-direction end of the workpiece W. Even if the backup plate 4 is used, if it is not divided in the X direction, it is not possible to bend the Y-direction end of the workpiece W in the X direction. According to this embodiment, since the divided plate unit 41 is used, it is possible to bend the Y-direction end of the workpiece W in both the X and Y directions.

[0059] Here, the X-direction central tab 434 having the curved surface portion 434R for preventing damage to the workpiece W is provided with a slit 435. This facilitates bending deformation in the Y direction of the cover 43. The X-direction central tab 434 hanging down from the top plate 431 extends relatively long in the Y direction. If the slit 435 was not provided, the X-direction central tab 434 could become a rib that increases the bending rigidity of the top plate 431 in the Y direction. However, by providing the slit 435, a bending allowance of the slit width can be given to the X-direction central tab 434. Therefore, the bendability of the cover 43 in the Y direction can be improved.

[0060] [Examples of using dies and punches] The pair of dies 2 shown in this embodiment can adjust the die width d for each pair of split dies 21. The punch 3 can adjust the amount of descent (amount of pressure applied to the workpiece W) for each split punch 31. Therefore, the pair of dies 2 and punch 3 can be used in the manner illustrated in Figs. 10 to 12. In Figs. 10 to 12, each (A) shows a side view of the punch unit 30, and each (B) shows a top view of the pair of dies 2. Although the backup plate 4 is omitted in Figs. 10 to 12, the backup plate 4 consisting of an array of split plate units 41 is also applied in these examples.

[0061] 10(A) and 10(B) are schematic diagrams showing a first use example of a pair of dies 2 and punches 3. In the first use example, as shown in FIG. 10(A), the protrusion amount of the multiple split punches 31 is constant, while as shown in FIG. 10(B), the split dies 21 have different die inter-widths d. In the split dies 21 arranged in the X direction, the pair of split dies 21 arranged in the central region in the X direction have the widest die inter-width d1. In contrast, the pair of split dies 21 arranged at the ends in the X direction have the narrowest die inter-width d2. The pair of split dies 21 between them have a gradually narrower die inter-width d from the central region in the X direction toward the ends.

[0062] When the protrusion amount of the split punch 31 is constant and the die gap width d of the split die 21 is different, the curvature of the workpiece W can be made to differ in the X direction. Specifically, the workpiece W is bent with a small curvature (radius of curvature = large) at the location of the wide die gap width d1, and with a large curvature (radius of curvature = small) at the location of the narrow die gap width d2. In this first usage example, since the protrusion amount of the split punch 31 is constant, a one-piece punch (one punch extending in the X direction) can be used as the punch 3 instead of a split type.

[0063] 11(A) and (B) are schematic diagrams showing a second usage example of a pair of a die 2 and a punch 3. In the second usage example, as shown in Fig. 11(A), the protrusion amounts of the multiple split punches 31 are different, while as shown in Fig. 11(B), the inter-die width d of the split die 21 is set to a constant different width. In a group of split punches 31 arranged in the X direction, the protrusion amount of each split punch 31 is set so that the protrusion amount of the split punch 31 arranged in the central region in the X direction is the largest and the protrusion amount gradually decreases toward the end in the X direction.

[0064] The curvature of the workpiece W can also be made to differ in the X direction by varying the protrusion amount of the split punch 31 and keeping the die gap d of the split die 21 constant. Specifically, the workpiece W is bent with a small curvature at the portion pressed by the split punch 31 at the end with a small protrusion amount, and is bent with a large curvature at the portion pressed by the split punch 31 in the central region with a large protrusion amount. In this second usage example, since the die gap d of the split die 21 is constant, one-piece dies can be used as the first die 2A and the second die 2B, rather than split dies.

[0065] 12(A) and (B) are schematic diagrams showing a third use example of a pair of die 2 and punch 3. In the third use example, as shown in Fig. 12(A), a small punch unit 30 is used for a workpiece W having a small width in the X direction. Here, a workpiece W having an X direction width that can be pressed down by four split punches 31 is shown as an example.

[0066] In the case of such a workpiece W, as shown in Fig. 12(B), the split dies 21 used are four sets of split dies 21 directly below the four split punches 31. Although not shown, a split plate unit 41 is placed on each of the four sets of split dies 21. Therefore, bending processing in the XY directions can be performed on the workpiece W. In other words, even if the punch unit 30 is replaced with a smaller one, the pair of dies 2 and the backup plate 4 do not require a change of setup.

[0067] A pair of die 2 and punch 3 can be used in a suitable combination of the three examples of use shown in Figures 10 to 12. For example, as shown in Figure 11(A), the split punch 31 can be used in a combination in which the protrusion amounts are different, and the split die 21 can be used in a combination in which the die gap width d is different, as shown in Figure 10(B).

[0068] [Back-up plate with sensing opening] The amount of descent of the punch 3 is controlled by the control device 5. M2 By controlling the operation of the punch 3, it is possible to perform high-precision adjustments. However, since springback occurs in the workpiece W, the bending process may not actually be performed on the workpiece W according to the amount of descent of the punch 3. For this reason, it is desirable to sense the bent shape of the workpiece W at appropriate points and perform bending on the workpiece W based on the results of the sensing.

[0069] However, when the backup plate 4 is interposed between the workpiece W and the pair of dies 2, the bottom surface of the workpiece W is blocked, making it difficult to measure the shape of the workpiece W from the die 2 side. In this case, it becomes difficult to adjust the degree of bending by the punch 3 while measuring the actual bending condition of the workpiece W. In view of this, an example is shown here in which an opening is provided in the backup plate 4 to enable shape sensing of the workpiece W passing through the transport path T from the lower side of the backup plate.

[0070] Fig. 13(A) is a top view of a backup plate 4 with an opening 44, and Fig. 13(B) is a cross-sectional view taken along line XIIIB-XIIIB of Fig. 13(A). The backup plate 4 is formed by arranging a plurality of divided plate units 41 in the X direction, as in the above example. Of the group of divided plate units 41, divided plate unit 41A at the center in the X direction and divided plate units 41B and 41C near both ends in the X direction are provided with openings 44. The openings 44 are holes that penetrate the backup plate 4 in the thickness direction (Z direction).

[0071] The opening 44 is a circular hole 4 4 1 and this circular hole 4 4 The long holes 4 arranged on the upstream and downstream sides of the Y direction of the 4 2 and 4. 4 1 and long hole 4 4 A shape measuring sensor 61 is disposed corresponding to each of the workpieces W and the back-up plate 4. The shape measuring sensor 61 measures the bent shape of the workpiece W through the opening 44. According to this embodiment, even if the backup plate 4 is present below the workpiece W, it is possible to cause the shape measuring sensor 61 to sense the bent shape of the workpiece W through the opening 44.

[0072] As the shape measuring sensor 61, a sensor capable of measuring the shape of the workpiece W in a contact or non-contact manner can be used. As a contact type sensor, for example, a contact type displacement sensor having a contactor that comes into contact with the lower surface of the workpiece W and a drive mechanism such as a spindle or rod cylinder can be used. When using this sensor, the circular hole 4 4 1 and long hole 4 4 The contacts are projected onto the conveying path T through the respective contact holes 4 and 5. As the non-contact type sensor, an optical sensor such as a reflective spot laser sensor, a reflective light quantity sensor, or a photoelectric sensor using infrared light can be used. When an optical sensor is used, its measurement light path passes through the circular hole 4. 4 1 and long hole 4 42. Alternatively, an optical sensor having a long measurement area in one direction, such as a laser line sensor, may be used. Furthermore, an eddy current sensor, an ultrasonic sensor, or an image sensor may be used as the shape measurement sensor 61.

[0073] According to this embodiment, it is possible to realize highly accurate bending of the workpiece W based on the sensing result of the bent shape of the workpiece W by the shape measuring sensor 61. That is, if the sensing result shows that the curved shape of the workpiece W is not as designed, the control device 5 (FIG. 3) operates the punch drive motor 32 to lower the punch 3, and re-bends the workpiece W at the same location as previously bent. On the other hand, if the curved shape of the workpiece W is as designed, the control device 5 operates the work transport mechanism 51 to intermittently feed the workpiece W by one pitch.

[0074] As shown in FIG. 13(B), a circular hole 4 4 1 is a circular hole arranged directly below the punch 3, while a pair of long holes 4 4 2 is a long hole that is elongated in the Y direction. When the divided plate unit 41A is pressed downward by the punch 3, the portion directly below the punch 3 becomes the bending center of the divided plate unit 41A. Therefore, the circular hole 4 4 On the other hand, the portion shifted from the bending center to the upstream or downstream side is pulled toward the bending center by the bending of the divided plate unit 41A. 4 The center position of the long hole 4 is relatively largely displaced in the horizontal direction before and after pressing. 4 2 has a longitudinal shape in the Y direction, the measurement axis of the shape measuring sensor 61 is the long hole 4 4 Therefore, the shape measuring sensor 61 fixedly disposed below the divided plate unit 41A can measure the shape of the long hole 4. 4 Through 2, it is possible to sense the shape of the workpiece W before and after pressing.

[0075] [Modification of the backup plate] 14 is a plan view of a backup plate 4A according to a modified example. In the above-described embodiment, a divided plate unit 41 in which each divided piece is completely separated is exemplified. The backup plate 4A shown here is a slit-type backup plate in which the divided pieces are partially connected to each other.

[0076] The backup plate 4A is composed of a plate body 45 and a plurality of slit pieces 46 provided in the plate body 45. The upstream and downstream portions of the plate body 45 in the Y direction are divided regions 45A, and the central region of the plate body 45 in the Y direction is a connecting region 45B. The slit pieces 46 are arranged in the dividing region 45A. Each slit piece 46 is partially separated from each other by a V-shaped cutout portion 47 extending in the Y direction, and the remaining portions are connected to each other in the connecting region 45B. That is, in the dividing region 45A, the plurality of slit pieces 46 are arranged in parallel in the X direction, and in the connecting region 45B, the plurality of slit pieces 46 are integrally connected.

[0077] Each slit piece 46 upstream in the Y direction is placed on a first die piece 21A (FIG. 1) of a pair of split dies 21, and each slit piece 46 downstream in the Y direction is placed on a second die piece 21B. End locking pieces 48 for bridging the backup plate 4A across the frame member 11 are provided on both ends of the plate body 45 in the X direction.

[0078] According to this backup plate 4A, the multiple slit pieces 46 arranged in the X direction can be deformed independently. In other words, when the workpiece W is pressed down by the split punch 31, the slit pieces 46 arranged opposite the split punch 31 elastically deform independently. Therefore, the backup plate 4A according to the modified example can also follow the three-dimensional deformation of the workpiece W.

[0079] FIG. 15 is a diagram showing another modified example of the backup plate. In the above embodiment, as shown in FIG. 15(A), an example in which one split plate unit 41 is arranged on one split die 21 (one split punch 31) has been shown. Alternatively, multiple split plate units 41 may be arranged on one split die 21 (one split punch 31). FIG. 15(B) shows an example in which two split plate units 41A and 41B are arranged on one split die 21. According to this modified example, the backup plate 4 is divided further in the X direction. Therefore, as is clear from a comparison between the right views of FIG. 15(A) and (B), the degree of freedom of deformation in the X direction can be increased.

[0080] [Inventions included in the above embodiments] A bending apparatus according to one aspect of the present invention comprises a pair of dies arranged below a workpiece transport path and spaced apart from each other in the transport direction of the workpiece, a punch arranged between the pair of dies and above the transport path, and a backup plate supported by the pair of dies and interposed between the workpiece passing through the transport path and the pair of dies, the backup plate including a portion in which a plurality of divided pieces are arranged in the width direction of the workpiece perpendicular to the transport direction.

[0081] In the above bending apparatus, it is preferable that the plurality of divided pieces are composed of a plurality of divided plate units separated from each other, each of the divided plate units is supported by the pair of dies, and the plurality of divided plate units are arranged in parallel in the width direction.

[0082] According to this bending device, the divided plate pieces are supported by a pair of dies, and therefore deform independently in the direction along the conveying path. Also, the divided plate pieces can deform independently in the width direction. Therefore, the backup plate can be made to follow the three-dimensional deformation of the workpiece.

[0083] In the above-mentioned bending processing device, the multiple divided pieces may consist of multiple slit pieces, some of which are separated from each other by cutout portions extending in the conveying direction and the remaining portions are connected to each other, and the backup plate may be configured to include a divided region in which the multiple slit pieces are arranged in parallel in the width direction, and a connecting region that connects the multiple slit pieces together.

[0084] According to this bending apparatus, the plurality of slit pieces arranged in the width direction can be deformed independently, and therefore the backup plate can be adapted to follow three-dimensional deformation of the workpiece.

[0085] In the above bending apparatus, it is preferable that the punch and / or the pair of dies are provided separately in correspondence with each of the divided pieces of the backup plate.

[0086] According to this bending apparatus, it is possible to perform bending on the workpiece in units of the divided pieces, thereby increasing the bending resolution and enabling more precise three-dimensional bending of the workpiece.

[0087] In the above bending processing apparatus, it is preferable that the pair of dies consists of a group of pairs of split dies arranged corresponding to each of the split pieces of the backup plate, and further includes a die spacing adjustment mechanism that adjusts the die spacing between one and the other of the pair of split dies on a per-split die basis.

[0088] According to this bending device, the die gap between the pair of split dies can be freely adjusted. Each split die is assigned to a split piece of the backup plate. Therefore, when the workpiece is pressed by the punch, the bending shape of the workpiece can be changed for each split die according to the die gap. This makes it possible to perform a variety of three-dimensional bending processes on the workpiece.

[0089] In the above-mentioned bending apparatus, it is preferable that the punch consists of a group of split punches arranged corresponding to each of the split pieces of the backup plate, and the apparatus further comprises a punch drive mechanism for individually moving each of the split punches forward and backward relative to the workpiece.

[0090] According to this bending device, it is possible to adjust the degree of pressure applied to the workpiece by each divided punch, thereby enabling the workpiece to be bent more precisely in the width direction.

[0091] In the above bending apparatus, it is preferable that the backup plate is made of a laminated body in which a plurality of unit plates are stacked.

[0092] By making the backup plate a laminated structure, the elastic deformation area of ​​the backup plate can be increased, so that even when the punch presses the workpiece so as to cause plastic deformation, the backup plate can only undergo elastic deformation.

[0093] In the above-mentioned bending apparatus, it is preferable that the apparatus further comprises a cover that is placed over the stack from above, the cover having a top plate that contacts the unit plate of the top layer of the stack and a tab that abuts against a side of the stack.

[0094] According to this bending apparatus, the side surfaces of the laminate are restrained by tabs, so that even if the laminate is curved and deformed to follow the workpiece, interlaminar slippage between the unit plates can be restricted.

[0095] In this case, it is preferable that the unit plates are rectangular plates, the stack has a rectangular parallelepiped shape, and the tabs include a first tab abutting a first side surface of the rectangular parallelepiped and a second tab abutting a second side surface perpendicular to the first side surface.

[0096] According to this bending device, the unit plates can be restrained by the first and second tabs arranged on the sides perpendicular to each other with respect to the laminate, so that interlaminar slippage between the unit plates can be reliably restricted.

[0097] In the above bending processing device, it is desirable that the laminate has a rectangular parallelepiped shape elongated in the conveying direction, the first side is a side extending along the conveying direction, and the first tab is provided with a slit extending in the vertical direction.

[0098] When a first tab hanging down from the top plate is present on a first side surface extending along the transport direction, the cover is less likely to bend in the direction along the transport direction. According to the above configuration, the first tab is provided with a slit, so that the cover can be easily bent.

[0099] In the bending apparatus described above, it is preferable that the backup plate has an opening that enables sensing of the workpiece passing through the transport path from a lower side of the backup plate.

[0100] With this bending device, even if a backup plate is placed below the workpiece, the bending shape and the like of the workpiece can be sensed by a required sensor through the opening. As a result, the bending shape and the like of the workpiece can be sensed at appropriate locations, and the results can be reflected in the bending process to achieve high-precision bending.

[0101] In the bending apparatus, it is preferable that the pair of dies is a group of a pair of split dies, and the split pieces of the backup plate are arranged in a plurality for each of the split dies. According to this aspect, the degree of freedom of deformation of the backup plate in the X direction can be increased. [Explanation of symbols]

[0102] 1 Bending equipment 2 Pair of dies 21 Pair of split dies 24 Die drive motor (die spacing adjustment mechanism) 3 Punch 32 Punch drive motor (punch drive mechanism) 4, 4A Backup plate 4P unit plate 4X 1st side 4Y 2nd side 41 Divided plate unit (divided piece) 42 Plate laminate (laminated body) 43 Cover 431 Tabletop 432 Y-direction tab (tab / second tab) 433 X-direction tab (tab / first tab) 434 X-direction center tab (tab / first tab) 435 Slit 44 Opening 45A split area 45B Connection area 46 Slit piece (split piece) 47 Cutout W work T Transport route d Die spacing M1 Die Adjustment Mechanism M2 punch drive mechanism

Claims

1. A pair of dies are disposed below a workpiece conveying path and spaced apart from each other in a conveying direction of the workpiece; a punch disposed between the pair of dies and above the transport path; a backup plate supported by the pair of dies and interposed between the workpiece passing through the conveying path and the pair of dies; the backup plate includes a portion in which a plurality of divided pieces are arranged in a width direction of the workpiece perpendicular to the conveying direction, The plurality of divided pieces are each composed of a plurality of divided plate units separated from one another, a bending apparatus in which each of the divided plate units is supported by the pair of dies, and the plurality of divided plate units are arranged in parallel in the width direction.

2. A pair of dies arranged below a workpiece conveying path and spaced apart from each other in the workpiece conveying direction; a punch disposed between the pair of dies and above the transport path; a backup plate supported by the pair of dies and interposed between the workpiece passing through the conveying path and the pair of dies; the backup plate includes a portion in which a plurality of divided pieces are arranged in a width direction of the workpiece perpendicular to the conveying direction, the plurality of divided pieces are each made up of a plurality of slit pieces, each of which is separated from the other by a notch portion extending in the conveying direction and the remaining portions of which are connected to each other; The backup plate includes a dividing region in which the plurality of slit pieces are arranged in parallel in the width direction, and a connecting region that integrally connects the plurality of slit pieces.

3. A pair of dies arranged below a workpiece conveying path and spaced apart from each other in the workpiece conveying direction; a punch disposed between the pair of dies and above the transport path; a backup plate supported by the pair of dies and interposed between the workpiece passing through the conveying path and the pair of dies; the backup plate includes a portion in which a plurality of divided pieces are arranged in a width direction of the workpiece perpendicular to the conveying direction, The punch is provided separately to correspond to each of the divided pieces of the backup plate.

4. In the bending apparatus according to any one of claims 1 to 3, The pair of dies are provided separately to correspond to each of the divided pieces of the backup plate.

5. The bending apparatus according to claim 4, the pair of dies is composed of a group of pairs of split dies arranged corresponding to each of the split pieces of the backup plate, The bending apparatus further includes a die gap adjustment mechanism that adjusts a die gap between one and the other of the pair of split dies for each split die.

6. The bending apparatus according to claim 4 or 5, the punch comprises a group of split punches arranged corresponding to each of the split pieces of the backup plate, The bending apparatus further includes a punch drive mechanism for individually moving each of the split punches forward and backward relative to the workpiece.

7. A pair of dies arranged below a workpiece conveying path and spaced apart from each other in the workpiece conveying direction; a punch disposed between the pair of dies and above the transport path; a backup plate supported by the pair of dies and interposed between the workpiece passing through the conveying path and the pair of dies; the backup plate includes a portion in which a plurality of divided pieces are arranged in a width direction of the workpiece perpendicular to the conveying direction, The backup plate is made of a laminate of a plurality of unit plates, Further comprising a cover that is placed on the stack from above, The bending apparatus, wherein the cover has a top plate that comes into contact with the unit plate of the uppermost layer of the stack, and a tab that abuts against a side surface of the stack.

8. The bending apparatus according to claim 7, The unit plates are rectangular plates, and the stack has a rectangular parallelepiped shape; The bending device, wherein the tab includes a first tab that abuts against a first side surface of the rectangular parallelepiped, and a second tab that abuts against a second side surface perpendicular to the first side surface.

9. The bending apparatus according to claim 8, The laminate has a rectangular parallelepiped shape that is elongated in the conveying direction, The first side surface is a side surface extending along the transport direction, The first tab is provided with a slit extending in the vertical direction.

10. A pair of dies arranged below a workpiece conveying path and spaced apart from each other in the workpiece conveying direction; a punch disposed between the pair of dies and above the transport path; a backup plate supported by the pair of dies and interposed between the workpiece passing through the conveying path and the pair of dies; the backup plate includes a portion in which a plurality of divided pieces are arranged in a width direction of the workpiece perpendicular to the conveying direction, The bending apparatus, wherein the backup plate has an opening that enables sensing of the workpiece passing through the conveying path from a lower side of the backup plate.

11. A pair of dies arranged below a workpiece conveying path and spaced apart from each other in the workpiece conveying direction; a punch disposed between the pair of dies and above the transport path; a backup plate supported by the pair of dies and interposed between the workpiece passing through the conveying path and the pair of dies; the backup plate includes a portion in which a plurality of divided pieces are arranged in a width direction of the workpiece perpendicular to the conveying direction, The pair of dies is composed of a group of a pair of split dies, A bending apparatus, wherein a plurality of the split pieces of the backup plate are arranged for one of the split dies.

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