Bending device

Abstract

To downsize a bending device (1) for performing feeding operation, twisting operation, and the like of a workpiece (S) by using an articulated robot (40), and enable a manufacturing cost to decrease.SOLUTION: A bending device is configured to: hold a workpiece between a bending die 21 and a clamping die 22, and bring a pressure die 23 into a state of contacting with the workpiece; then, while maintaining the state, turn the bending die and the clamping die to bend the workpiece; thereafter, when separating the pressure die and the clamping die from the workpiece, bring a movement restraining part (31 or 33) into contact with the chuck (30) or the workpiece to restrain movement of the workpiece; and when moving the workpiece in a feeding direction, move also the movement restraining part together. Thereby, while the pressure die is separated from the workpiece, the movement restraining portion can receive a force that attempts to cause the workpiece to spring back, so as to enable use of a small articulated robot.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a bending device that performs bending on a metal workpiece having an elongated shape and a predetermined number of bending positions. [Background technology]

[0002] In order to bend a metal workpiece such as a pipe into a predetermined shape, a bending device called a bender is used. This bending device is equipped with a metal mold called a "bending die" and a metal mold called a "clamping die", and the bending die has a circumferential bending side surface and a linear holding side surface that is continuous with the bending side surface. The clamping die is mounted at a position facing the holding side surface of the bending die, and by moving the clamping die in a direction toward the holding side surface of the bending die, it is possible to hold a workpiece such as a pipe between the holding side surface of the bending die and the clamping die. Furthermore, the bending die and the clamping die can be rotated as a whole around the central axis of the circumferential shape of the bending side surface. In the following, moving the clamping die in a direction toward the bending die will be referred to as "moving the clamping die forward", and moving the clamping die in a direction away from the bending die will be referred to as "moving the clamping die backward".

[0003] The bending device also has a chuck that grips and moves one end of the workpiece, and a die called a "pressure die." The pressure die is mounted in a position adjacent to the chuck side as seen from the clamping die, and can be moved parallel to the direction in which the clamping die moves toward the bending die.

[0004] When bending a workpiece, the workpiece is gripped by a chuck, and then the chuck is moved to move the workpiece so that the bending position set on the workpiece is a predetermined position (a position slightly forward) relative to the position between the bending die and the clamping die. Next, the clamping die is advanced toward the bending die to sandwich the workpiece between the bending die and the clamping die, and the pressure die is also moved in the same direction as the clamping die to abut against the workpiece. In the following, moving the pressure die in the direction to abut against the workpiece is referred to as "advancing the pressure die", and moving the pressure die in the direction away from the workpiece is referred to as "retracting the pressure die". Then, the bending die and the clamping die are rotated while they are in abutment against the workpiece. The rotation direction is the direction in which the clamping die moves away from the pressure die (hereinafter, this direction is referred to as the "bending direction"). Since the workpiece is clamped between the bending die and the clamping die, the workpiece tries to rotate together with the bending die and the clamping die, but since it is held down by the pressure die, the workpiece on the chuck side of the pressure die cannot rotate. Therefore, the workpiece is bent such that the part from the pressure die to the clamping die is wrapped around the bending side of the bending die. The angle at which the workpiece is bent at this time corresponds to the angle at which the bending die and the clamping die are rotated, and the radius at which the workpiece is bent corresponds to the radius of the bending side of the bending die.

[0005] After bending one portion of the workpiece in the above manner, the clamping die and the pressure die are moved back to separate them from the workpiece, and then the bending die and the clamping die, which have been rotated in the bending direction, are returned to their original positions by rotating them in the opposite direction to the bending direction. Then, the chuck is moved in the axial direction of the workpiece to move the workpiece so that the next bending position set on the workpiece is a predetermined position relative to the position between the bending die and the clamping die. In addition, when changing the bending direction of the workpiece, the workpiece is rotated around the axis. In the following, the operation of moving the workpiece in the axial direction is referred to as the "feed operation", and the operation of rotating the workpiece around the axis is referred to as the "twist operation". Then, the clamping die is moved forward to clamp the workpiece, and the pressure die is moved forward to abut against the workpiece, and the bending die and the clamping die are rotated in the bending direction again to bend a new bending position on the workpiece. By repeating such steps, the workpiece is bent into a desired shape.

[0006] Among bending devices, a bending device has been proposed in which a chuck is attached to the tip of an articulated robot, and the chuck is moved or rotated using the articulated robot to perform feeding and twisting operations. The articulated robot can flexibly perform various operations other than feeding and twisting, making it possible to perform bending operations that were difficult with conventional bending devices. Furthermore, it is also possible to have the articulated robot pick up a stored workpiece and hold it between a bending die and a clamping die to perform bending, which can improve work efficiency (Patent Document 1). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 6654351 Summary of the Invention [Problem to be solved by the invention]

[0008] However, bending apparatuses that use articulated robots to perform feeding and twisting operations on workpieces have the problem that the apparatuses become large in size and are also expensive to manufacture. The reasons for this are as follows.

[0009] First, metal materials undergo elastic deformation when a load is applied, but if a larger load is applied, the limit of elastic deformation is exceeded and the material undergoes plastic deformation, and the plastically deformed portion does not return to its original shape even when the load is removed. On the other hand, some deformation remains elastically deformed even after plastic deformation, so the elastically deformed portion returns to its original shape when the load is removed. This phenomenon in which the remaining elastically deformed portion tries to return to its original shape when the load is removed after plastic deformation is called "springback."

[0010] Here, since the bending process also plastically deforms the metal material, when the clamping die and the pressure die are separated from the workpiece after bending the workpiece, the workpiece tries to return slightly due to springback. When the articulated robot holds the end of the workpiece, the articulated robot receives the force of the workpiece trying to return due to springback. If the workpiece becomes thicker, the force due to springback also becomes larger, so there is a risk that the articulated robot will not be able to support the force or the entire articulated robot will tilt. In order to avoid this, a high-power and sturdy articulated robot is required, which results in a problem that the bending device becomes larger and the manufacturing cost becomes higher.

[0011] This invention has been made to solve the above-mentioned problems associated with the conventional technology, and aims to provide technology that makes it possible to miniaturize bending devices that use articulated robots to perform feeding and twisting operations on workpieces, while also reducing manufacturing costs. [Means for solving the problem]

[0012] In order to solve the above-mentioned problems, the bending apparatus of the present invention adopts the following configuration. A bending device (1) for bending a metal workpiece having a long shape and a predetermined number of bending positions, A chuck (30) for gripping one end side of the workpiece; an articulated robot (40) that moves the chuck that holds the workpiece; A bending die (21) having a bending side surface (21a) formed in a circumferential shape and a holding side surface (21b) formed in a linear shape continuous with the bending side surface; a clamping die (22) that is provided opposite the holding side surface of the bending die and that can hold the workpiece between the clamping die (22) and the holding side surface by moving toward the holding side surface; a die rotation unit (26) that rotates the bending die and the clamping die in a predetermined bending direction around a central axis of the circumferential shape of the bending side surface; A pressure die (23) provided at a position adjacent to the chuck side of the clamping die and movable in a direction parallel to the direction in which the clamping die approaches the holding side surface before the rotation; a control unit (50) for controlling the operations of the chuck, the articulated robot, the clamping die, the die rotating unit, and the pressure die; Equipped with The control unit is A feed control that uses the articulated robot to move the position of the chuck in the axial direction of the workpiece so that one of the bending positions on the workpiece is positioned relative to the holding side surface of the bending die and the clamping die; When the feed control is completed, the clamping die is brought close to the holding side surface to hold the workpiece between the holding side surface and the clamping die, and the pressure die is moved to abut against the workpiece, and the bending die and the clamping die are rotated in the bending direction using the die rotation unit to bend the workpiece. When the bending control is completed, the pressure die and the clamping die are separated from the workpiece, and the die rotating unit rotates the bending die and the clamping die in a direction opposite to the bending direction, thereby returning the bending die and the clamping die to their positions before the bending process. a control unit that repeatedly executes the above a number of times corresponding to the number of bending positions, At least during the return control and the feed control, a movement restraining unit (31, 33) is mounted which moves in the axial direction together with the workpiece while restraining the movement of the workpiece toward the pressure die by contacting the chuck or the workpiece. It is characterized by:

[0013] In the bending device of the present invention, the workpiece is clamped between the bending die and the clamping die, and the bending die and the clamping die are rotated in the bending direction while the pressure die is in contact with the workpiece, thereby bending the workpiece. After the bending process is completed, the pressure die and the clamping die are separated from the workpiece. At this time, the workpiece tries to move in the direction of the separating pressure die, so the movement of the workpiece is restricted by contacting the movement restriction part with the chuck or the workpiece. When the workpiece moves in the feed direction, the movement restriction part is also moved together with the workpiece.

[0014] In this way, while the pressure die is separated from the workpiece, the force of the workpiece trying to return due to spring back can be received by the movement restraint part. Therefore, the articulated robot can be made small enough to transport the workpiece, so that the bending device can be made smaller and the manufacturing costs of the bending device can be reduced.

[0015] In the bending apparatus of the present invention described above, the movement restraining portion may restrain the movement of the workpiece toward the pressure die while allowing the workpiece to rotate about its axis.

[0016] In this way, by using the articulated robot to rotate the workpiece about an axis, it is possible to change the direction in which the workpiece is bent.

[0017] The bending device of the present invention described above may also be equipped with a chuck and a movement constraint unit as described below. First, the chuck is a chuck that grips the workpiece from the direction of the end face and has a chuck shaft at a position coaxial with the gripped workpiece. The movement constraint unit is attached to the chuck shaft in a state in which it can rotate around the axis of the chuck shaft but cannot move in the axial direction. Then, the workpiece may be moved in the axial direction by moving the chuck shaft using a multi-joint robot, and the workpiece may be rotated around the axis by rotating the chuck shaft using a multi-joint robot.

[0018] In this way, a general-purpose articulated robot can be used, which makes it possible to manufacture the bending device even more easily.

[0019] Alternatively, in the bending device of the present invention described above, the movement constraint part that has been moved axially together with the workpiece during feed control may be returned to its position before movement as follows. That is, the movement constraint part is brought into contact with the workpiece at a position between the chuck and the pressure die, thereby constraining the movement of the workpiece toward the pressure die. Then, during the period from when the pressure die comes into contact with the workpiece during bending control until the bending control is completed, the movement constraint part is moved away from the workpiece, and the position of the movement constraint part is returned from the position to which it was moved axially together with the workpiece during feed control to the position before movement.

[0020] In this way, even if the movement constraint part is moved in the axial direction of the workpiece during feed control, it can be returned to its position before movement during bending control, so that in the next feed control, the movement constraint part can be moved from its original position in the axial direction of the workpiece. Therefore, even when feed control is performed multiple times, the movement range of the movement constraint part can be reduced, making it possible to further miniaturize the bending device. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is an explanatory diagram showing an overview of a bending device 1 according to a first embodiment. [Diagram 2] 1 is a perspective view showing an overview of a bending unit 20 mounted on a bending device 1 of a first embodiment. [Diagram 3] 1A to 1C are explanatory diagrams illustrating the first half of a general operation of bending a workpiece S in a bending unit 20. [Figure 4] 10 is an explanatory diagram of the latter half of a general operation of bending a workpiece S by the bending unit 20. FIG. [Diagram 5] 1 is an explanatory diagram showing a first half of an operation of the bending device 1 of the first embodiment when bending a workpiece S. FIG. [Figure 6] 5 is an explanatory diagram showing the latter half of the operation of the bending device 1 of the first embodiment bending the workpiece S. FIG. [Figure 7] FIG. 4 is an explanatory diagram showing an overview of a bending device 1 according to a second embodiment. [Figure 8] 11 is a perspective view showing an outline of a constraint die 33 mounted on a bending apparatus 1 of a second embodiment. FIG. [Figure 9] 10 is an explanatory diagram of the first half of the operation of the bending device 1 of the second embodiment when bending a workpiece S. FIG. [Figure 10] 10 is an explanatory diagram of the latter half of the operation of the bending device 1 of the second embodiment when bending the workpiece S. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] A. First Example: 1 is an explanatory diagram showing an overview of a bending device 1 of the first embodiment. The bending device 1 of the first embodiment includes a rectangular parallelepiped main body case 10, a bending unit 20 mounted on the upper surface of the main body case 10, a chuck 30, an articulated robot 40 provided next to the main body case 10, a control unit 50 housed within the main body case 10, and a power supply unit 60 that supplies operating power to various actuators and the control unit 50.

[0023] The bending unit 20 is a unit made up of the bending die 21 and pressure die 23, which will be described later, and a drive unit 26 that rotates the bending die 21. The bending die 21, pressure die 23, and the like are mounted on the top surface of the main body case 10, while the drive unit 26 is housed inside the main body case 10 below the bending die 21. Details of the bending unit 20 will be described later. The drive unit 26 in the first embodiment corresponds to the "die rotating unit" in the present invention.

[0024] The chuck 30 includes a cylindrical chuck body 30a, a pair of chuck jaws 30b protruding from an end face of the chuck body 30a, and a cylindrical chuck shaft 30c protruding coaxially from the end face of the chuck body 30a opposite to the chuck jaws 30b, and a gripped portion 30d having a thicker shaft diameter is formed at the tip end side of the chuck shaft 30c. As described later, the chuck 30 can grip a long workpiece S from the end face side using the chuck jaws 30b, and at this time, the workpiece S is gripped in a state where the shaft position of the workpiece S is coaxial with the chuck body 30a and the chuck shaft 30c.

[0025] Furthermore, the chuck shaft 30c is held by a bearing portion 31, and is rotatable around its axis but immovable in the axial direction (or immovable beyond a predetermined range). Furthermore, a guide portion 31a protrudes from the bearing portion 31, and the guide portion 31a is slidably fitted into a guide rail 11 attached to the upper surface of the main body case 10. Therefore, the bearing portion 31 is movable in the direction of the guide rail 11 (the feed direction of the workpiece S), but movement in a direction lateral to the feed direction is restricted. In the first embodiment, the bearing portion 31 corresponds to the "movement restricting portion" in this invention.

[0026] The articulated robot 40 includes a base 41 having a truncated cone shape, a short cylindrical body 42 attached to the base 41 so as to be rotatable around the axis of the base 41, a first arm 43 having a base attached to the upper part of the body 42, a second arm 44 having a base attached to the tip of the first arm 43, a third arm 45 having a base attached to the tip of the second arm 44, a fourth arm 46 having a base attached to the tip of the third arm 45, and a hand 47 attached to the tip of the fourth arm 46. The first arm 43 is rotatable in a manner bending with respect to the axial direction of the body 42, and the second arm 44 is rotatable in a manner bending with respect to the axial direction of the first arm 43. The third arm 45 is rotatable around the axis of the second arm 44 on the same axis. The fourth arm portion 46 is rotatable in a bending manner with respect to the axial direction of the third arm portion 45, and the hand portion 47 is rotatable coaxially with and about the axis relative to the fourth arm portion 46. Furthermore, a pair of hand claws 47a protrude from the tip of the hand portion 47, and these hand claws 47a can be moved in a direction approaching each other or in a direction separating them from each other.

[0027] A control unit 50 and a power supply unit 60 are housed inside the main body case 10, and the control unit 50 controls the overall operation of the bending apparatus 1. The power supply unit 60 also supplies power to various actuators (e.g., motors) (not shown) mounted on the bending apparatus 1 and the control unit 50 for their operation.

[0028] Fig. 2 is a perspective view showing an overview of the bending unit 20 mounted on the bending device 1 of the first embodiment. The bending unit 20 of the first embodiment includes a bending die 21, a clamping die 22, and a pressure die 23. The bending die 21 and the clamping die 22 are mounted on a rotating base 24, and the pressure die 23 is mounted on a pressure base 25. In Fig. 2, the rotating base 24 is shown with coarse diagonal lines, and the pressure base 25 is shown with fine diagonal lines. In addition, an actuator 22b for moving the clamping die 22 forward or backward is mounted on the rotating base 24, and an actuator 23b for moving the pressure die 23 forward or backward is mounted on the pressure base 25.

[0029] The bending die 21 is a substantially disk-shaped member, and the outer peripheral side surface of the bending die 21 includes a circumferential bending side surface 21a and a linear holding side surface 21b continuous with the bending side surface 21a. In addition, since the bending device 1 of the first embodiment is intended to bend a cylindrical or tubular workpiece S, shallow grooves having arc-shaped cross sections are formed in the bending side surface 21a and the holding side surface 21b.

[0030] The clamping die 22 is a member having a substantially rectangular parallelepiped shape, and is mounted with the end face on the long side of the rectangular parallelepiped shape facing the holding side surface 21b of the bending die 21, and a shallow arc-shaped groove is formed in the end face 22a facing the holding side surface 21b. Therefore, when the clamping die 22 is advanced by the actuator 22b with the workpiece S inserted between the bending die 21 and the clamping die 22, it becomes possible to clamp the workpiece S between the bending die 21 and the clamping die 22.

[0031] The rotating base 24 is rotatable about the central axis CL of the bending side surface 21a of the bending die 21, and by driving a drive unit 26 mounted below the rotating base 24, it is possible to rotate the rotating base 24 together with the bending die 21, the clamping die 22, and the actuator 22b on the rotating base 24. The rotation direction indicated by the dashed arrow in Fig. 2 indicates the bending direction.

[0032] The pressure die 23 is also a member of a substantially rectangular parallelepiped shape similar to the clamping die 22, and a shallow groove of a circular arc shape is drilled on the end face 23a on the long side of the rectangular parallelepiped shape. The pressure die 23 is mounted at a position adjacent to the clamping die 22 and at a position on the side from which the clamping die 22 moves away when the rotating base 24 is rotated in the bending direction, and the direction of the pressure die 23 is parallel to the clamping die 22, and the end face 23a on which the groove is drilled faces in the same direction as the end face 22a of the clamping die 22. Therefore, when the pressure die 23 is advanced by the actuator 23b in a state in which the workpiece S is inserted between the bending die 21 and the clamping die 22, it is possible to abut the end face 23a of the pressure die 23 against the workpiece S from the same direction as the clamping die 22.

[0033] In addition, the pressure base 25 is connected to an actuator (not shown), and by driving the actuator, it is possible to move the pressure base 25 together with the pressure mold 23 and actuator 23b on the pressure base 25 in the feed direction of the workpiece S or in the reverse direction. The bending unit 20 itself described above is a general one, and bends the workpiece S as follows.

[0034] 3 and 4 are explanatory diagrams showing the operation of the bending unit 20 to bend a workpiece S such as a pipe. When bending the workpiece S, first, the workpiece S is inserted between the bending die 21 and the clamping die 22, and then the workpiece S is moved in the axial direction (i.e., the feed direction) to position the bending position on the workpiece S to a predetermined position (a position slightly forward) with respect to the position between the bending die 21 and the clamping die 22. FIG. 3(a) shows a state in which the workpiece S is positioned so that the bending position on the workpiece S is slightly forward between the bending die 21 and the clamping die 22. The process of first inserting the workpiece S between the bending die 21 and the clamping die 22 and positioning the workpiece S with respect to the position between the bending die 21 and the clamping die 22 is hereinafter referred to as the "insertion process".

[0035] Next, the clamping die 22 is advanced so that the workpiece S is sandwiched between the clamping die 22 and the bending die 21, and the pressure die 23 is advanced so that the pressure die 23 is brought into contact with the workpiece S. FIG. 3(b) shows a state in which the workpiece S is sandwiched between the clamping die 22 and the bending die 21 and the pressure die 23 is brought into contact with the workpiece S. In this state, the bending die 21 and the clamping die 22 are rotated in the bending direction around the central axis of the bending side surface 21a (see FIG. 2) of the bending die 21. Since the workpiece S is held down by the pressure die 23, when the bending die 21 and the clamping die 22 are rotated while the workpiece S is sandwiched, the workpiece S is bent in a state in which it wraps around the bending side surface 21a of the bending die 21, as shown in FIG. 3(c). Furthermore, as the bending die 21 and the clamping die 22 rotate while holding the workpiece S, the workpiece S is dragged and moves in the axial direction (feed direction). Accordingly, the pressure die 23 in contact with the workpiece S is also moved in the feed direction. Note that the process of holding the workpiece S between the bending die 21 and the clamping die 22 and bringing the pressure die 23 into contact with the workpiece S and then rotating the bending die 21 and the clamping die 22 in the bending direction will be referred to as the "bending process" below.

[0036] After the bending process is completed, the clamping die 22 is separated from the bending die 21 while the bending die 21 and the clamping die 22 are rotated. The pressure die 23 is also moved in the feed direction and separated from the workpiece S. As a result, the workpiece S is released from the restraint by the pressure die 23, and the workpiece S tries to return to its original shape slightly by springback. The broken line shown in FIG. 3(d) represents the movement of the workpiece S trying to return by springback. However, in reality, since the rear end side of the workpiece S is held by a chuck, the workpiece S does not return to its original shape even if the pressure die 23 is separated. Next, as shown in FIG. 3(e), the bending die 21 and the clamping die 22 are rotated in the opposite direction to return to their original positions, and the pressure die 23 is also returned to its original position. In addition, the process of returning the bending die 21, the clamping die 22 and the pressure die 23 to their original positions after separating them from the workpiece S will be referred to as the "return process" below.

[0037] After the return step is completed, the workpiece S is moved in the feed direction to position the next bending position at a predetermined position between the bending die 21 and the clamping die 22. FIG. 4(a) shows the state in which the next bending position has been positioned. The process of moving the workpiece S in the feed direction to position the next bending position is hereinafter referred to as the "feed step". When changing the bending direction of the workpiece S, the workpiece S is rotated around its axis (hereinafter referred to as "twisted rotation") before or after the feed step (during the feed step, if necessary).

[0038] After the feeding process is completed, the bending process is started again for the new bending position. That is, as shown in FIG. 4(b), the clamping die 22 is advanced to clamp the workpiece S, and the pressure die 23 is brought into contact with the workpiece S. Then, as shown in FIG. 4(c), the bending die 21 and the clamping die 22 are rotated in the bending direction, and the pressure die 23 is moved in the feeding direction, thereby bending the workpiece S at the new bending position. After the bending process at the new bending position is completed, the above-mentioned return process is performed, and then the above-mentioned feeding process is performed to position the workpiece S so that the next new bending position is a predetermined position. By performing this series of processes for all bending positions set on the workpiece S, the workpiece S can be bent into a desired shape.

[0039] As described above, when the clamping die 22 and the pressure die 23 are separated from the workpiece S after bending the workpiece S, the force of the workpiece S trying to return due to springback is applied to the chuck gripping the other end of the workpiece S. For this reason, when the chuck is attached to the tip of the articulated robot, a large articulated robot capable of withstanding a large force is required. In contrast, in the bending device 1 of the first embodiment shown in FIG. 1, the chuck 30 is supported by the bearing portion 31, and the force due to the springback of the workpiece S is received by the bearing portion 31, so that the force is not applied to the articulated robot 40. For this reason, it is possible to use a small articulated robot 40 that can lift the workpiece S. This point will be described below.

[0040] 5 and 6 are explanatory diagrams showing the operation of the bending device 1 of the first embodiment when bending the workpiece S. When bending the workpiece S, the bearing portion 31 (and the chuck 30) is moved to the rearmost position along the guide rail 11. The bearing portion 31 may be self-propelled along the guide rail 11, or may be moved manually by an operator. Alternatively, the bearing portion 31 (and the chuck 30) may be moved by the articulated robot 40 by gripping the bearing portion 31 or the chuck 30 with the hand claws 47a of the articulated robot 40.

[0041] Thereafter, the workpiece S is gripped by the hand claws 47a of the articulated robot 40 and transported, so that the rear end of the workpiece S is gripped by the chuck claws 30b of the chuck body 30a. In the following description, an actuator (not shown) is built into the chuck body 30a, and the actuator opens and closes the chuck claws 30b under the control of the control unit 50 to grip the workpiece S. However, the chuck claws 30b may be opened and closed by the operator's button operation. Alternatively, the operator may manually open and close the chuck claws 30b. FIG. 5(a) shows a state in which the rear end of the workpiece S that has been gripped by the hand claws 47a and transported by the articulated robot 40 is gripped by the chuck claws 30b of the chuck 30.

[0042] As described above, after the rear end of the workpiece S is gripped by the chuck jaws 30b of the chuck 30, the articulated robot 40 releases the workpiece S and then grips the gripped portion 30d of the chuck 30. Then, the articulated robot 40 pushes the gripped portion 30d to move the bearing portion 31 in the feed direction, thereby positioning the workpiece S so that the bending position set on the workpiece S is a predetermined position (a position slightly forward) between the bending die 21 and the clamping die 22 of the processing unit 20. In this manner, the input step described above with reference to FIG. 3(a) is performed. FIG. 5(b) shows a state in which the bending device 1 of the first embodiment has performed the input step.

[0043] Once the step of feeding the workpiece S is complete, the bending step is then carried out. That is, the clamping die 22 and the pressure die 23 are advanced to abut against the workpiece S (see FIG. 3(b)), and then the bending die 21 and the clamping die 22 are rotated in the bending direction to bend the workpiece S (see FIG. 3(c)). At this time, the workpiece S is dragged and moves in the feed direction, so the pressure die 23 is also moved in the feed direction in accordance with this movement, and the bearing portion 31 and the chuck 30 are also moved in the feed direction using the articulated robot 40. FIG. 5(c) shows the state after the bending step has been carried out in this manner.

[0044] When the bending process is completed, the return process is started. That is, the clamping die 22 and the pressure die 23, which have been holding the workpiece S to prevent it from moving, are separated from the workpiece S (see FIG. 3(d)). FIG. 6(a) shows the state in which the clamping die 22 (and the pressure die 23), which have been holding the workpiece S to prevent it from moving, are separated from the workpiece S. When the clamping die 22 and the pressure die 23 are separated from the workpiece S, the workpiece S tries to return by springback. However, in the bending device 1 of the first embodiment, the chuck shaft 30c of the chuck 30 is supported by the bearing portion 31, so the workpiece S does not return by springback. That is, the force of the workpiece S trying to return by springback is received by the bearing portion 31, and not by the articulated robot 40.

[0045] Next, the bending die 21 and the clamping die 22 are rotated in the direction opposite to the bending direction, and the pressure die 23 is also moved in the direction opposite to the feed direction, so that they are returned to their positions before bending (see FIG. 3(e)). FIG. 6(b) shows the state in which the bending device 1 of the first embodiment has thus performed the return process.

[0046] After the return step is completed, the chuck 30 and the bearing portion 31 are moved in the feed direction by the articulated robot 40 to position the next bending position set for the workpiece S relative to the position between the bending die 21 and the clamping die 22 (see FIG. 4(a)). When the bending direction of the workpiece S is changed, the workpiece S is twisted and rotated around its axis at this stage. As described above with reference to FIG. 1, the chuck 30 has a structure in which the chuck shaft 30c is supported by the bearing portion 31, and the articulated robot 40 grips the gripped portion 30d of the chuck shaft 30c. Therefore, the workpiece S can be twisted and rotated by rotating the chuck shaft 30c around its axis by the articulated robot 40. FIG. 6(c) shows a state in which the bending device 1 of the first embodiment has performed the feed step.

[0047] When the feeding step is completed in this manner, the bending step is performed as described above with reference to Fig. 5(c), and the return step is then performed as described above with reference to Fig. 6(a) and Fig. 6(b). If there are any bending positions that have not yet been bent, the feeding step is performed as described above with reference to Fig. 6(c), and the bending step and return step are then performed again. By repeating such operations, it is possible to bend the workpiece S into the desired shape.

[0048] The control of the chuck 30 and the articulated robot 40 for performing the input process shown in Fig. 5(a) (hereinafter referred to as input control) is performed by a control unit 50 housed in the main body case 10 of the bending apparatus 1. The control of the articulated robot 40 for performing the feed process shown in Fig. 5(b) and Fig. 6(c) (hereinafter referred to as feed control), the control of the processing unit 20 and the articulated robot 40 for performing the bending process shown in Fig. 5(c) (hereinafter referred to as bending control), and the control of the processing unit 20 and the articulated robot 40 for performing the return process shown in Fig. 6(a) and Fig. 6(b) (hereinafter referred to as return control) are also performed by the control unit 50.

[0049] As described above, in the bending apparatus 1 of the first embodiment, even if the clamping die 22 and the pressure die 23 are separated from the workpiece S after the bending process is completed, the bearing portion 31 can receive the force of the workpiece S attempting to return to its original shape due to springback. For this reason, a small-sized articulated robot 40 capable of transporting the workpiece S can be used as the articulated robot 40. As a result, it is possible to reduce the size of the bending apparatus 1 and, further, the manufacturing costs can be reduced.

[0050] Furthermore, in the bending apparatus 1 of the first embodiment, the hand unit 47 at the tip of the articulated robot 40 grips the gripped portion 30d formed at the rear end of the chuck shaft 30c, and grips the workpiece S with the chuck 30 attached to the tip of the chuck shaft 30c. Therefore, since the distance from the tip of the articulated robot 40 to the chuck 30 is long, even when the hand unit 47 of the articulated robot 40 approaches the bending unit 20 to bend the vicinity of the rear end of the workpiece S, the hand unit 47 does not interfere with the bending unit 20. As a result, it is also possible to bend the vicinity of the rear end of the workpiece S.

[0051] B. Second Example: In the bending apparatus 1 of the first embodiment described above, the chuck shaft 30c protrudes from the chuck 30 that grips the workpiece S, and the chuck shaft 30c is supported by the bearing portion 31. Therefore, when the pressure die 23 is separated from the workpiece S after bending, the force of the workpiece S returning due to springback can be received by the bearing portion 31 that supports the chuck shaft 30c. However, before the pressure die 23 is separated from the workpiece S, the pressure die 23 abuts against the workpiece S, thereby receiving the springback force of the workpiece S. Therefore, a die (hereinafter, a constraining die) that abuts against the workpiece S from the same direction as the pressure die 23 may be provided at a position closer to the rear end of the workpiece S than the pressure die 23, and the constraining die may receive the springback force while the pressure die 23 is separated from the workpiece S. The bending apparatus 1 of the second modification will be described below.

[0052] 7 is an explanatory diagram showing an overview of the bending apparatus 1 of the second embodiment. The bending apparatus 1 of the second embodiment also includes a main body case 10, a bending unit 20, a chuck 30, a multi-joint robot 40, and a control unit 50 and a power supply unit 60 housed in the main body case 10, as in the bending apparatus 1 of the first embodiment shown in FIG. 1. However, in the bending apparatus 1 of the second embodiment, the chuck 30 is attached to a hand unit 47 of the multi-joint robot 40. Accordingly, the hand claws 47a (see FIG. 1) are not mounted on the hand unit 47 of the multi-joint robot 40, and the chuck 30 of the second embodiment does not include a chuck shaft 30c or a gripped unit 30d (see FIG. 1). Furthermore, the upper surface of the main body case 10 is not equipped with a bearing portion 31 (see FIG. 1) for supporting the chuck shaft 30c of the chuck 30, or a guide rail 11 (see FIG. 1) into which the guide portion 31a of the bearing portion 31 fits, but instead is equipped with a movable base 34 that is movable in the feed direction of the workpiece S, and a constraint mold 33 is mounted on the movable base 34. The bending device 1 of the second embodiment differs from the bending device 1 of the first embodiment in these respects, but is similar to the first embodiment in other respects. In the second embodiment, the constraint mold 33 corresponds to the "movement constraint portion" in the present invention.

[0053] Fig. 8 is a perspective view showing an overview of the constraint die 33 mounted on the bending device 1 of the second embodiment. For ease of understanding, the bending unit 20 is also shown in Fig. 8. As shown in the figure, the constraint die 33 is a member having a substantially rectangular parallelepiped shape similar to the clamping die 22 and pressure die 23 of the processing unit 20, and one end face 33a of the constraint die 33 has a shallow arc-shaped groove drilled therein, similar to the pressure die 23 and clamping die 22. The constraint die 33 is mounted on the opposite side of the pressure die 23 from the clamping die 22, in a state where it is aligned with the pressure die 23 (i.e., in the same orientation as the pressure die 23 and parallel to the pressure die 23).

[0054] In addition, an actuator 33b for moving the constraining mold 33 is also mounted on the moving base 34 on which the constraining mold 33 is mounted. When the constraining mold 33 is driven by the actuator 33b, the constraining mold 33 can be moved in the same direction as the pressure mold 23 moves on the pressure base 25. Therefore, in a state in which the workpiece S is sandwiched between the bending mold 21 and the clamping mold 22, the constraining mold 33 can be brought into contact with the workpiece S by advancing the constraining mold 33 with the actuator 33b, or moved back to separate the constraining mold 33 from the workpiece S. Furthermore, the moving base 34 can be moved in the feed direction of the workpiece S by an actuator (not shown). In FIG. 8, the constraining mold 33 and the moving base 34 moved in the feed direction are indicated by dashed lines.

[0055] 9 and 10 are explanatory diagrams showing the operation of the bending device 1 of the second embodiment bending the workpiece S. As shown in FIG. 9(a), when bending the workpiece S, the clamping die 22, the pressure die 23, and the restraining die 33 are retracted, the workpiece S is inserted between the bending die 21 and the clamping die 22, and the workpiece S is moved in the feed direction to position the bending position on the workpiece S at a predetermined position (a position slightly forward) between the bending die 21 and the clamping die 22. In the bending device 1 of the second embodiment, the chuck 30 is mounted on the tip of the articulated robot 40, so that the workpiece S can be positioned at a desired position by operating the articulated robot 40 with the rear end of the workpiece S gripped by the chuck 30.

[0056] Next, the clamping die 22 and the pressure die 23 are advanced so that the clamping die 22 and the bending die 21 clamp the workpiece S, and the pressure die 23 is brought into contact with the workpiece S. At this stage, the constraint die 33 is left in a retreated state. FIG. 9(b) shows a state in which the clamping die 22 and the pressure die 23 are brought into contact with the workpiece S, and the constraint die 33 is separated from the workpiece S. In this state, the bending die 21 and the clamping die 22 are rotated in the bending direction to bend the workpiece S. At this time, the workpiece S moves in the feed direction as if being dragged, so the pressure die 23 is also moved in the feed direction in accordance with this movement, and the position of the chuck 30 is also moved in the feed direction using the articulated robot 40. FIG. 9(c) shows a state in which the bending die 21 and the clamping die 22 are rotated, but at this stage, the constraint die 33 is still in a retreated state.

[0057] After the bending process is completed, the return process is started. As shown in FIG. 9(d), in the return process, the restraining die 33 is advanced to abut against the workpiece S, and then the clamping die 22 and the pressure die 23 are retracted to separate from the workpiece S. When the pressure die 23 is separated from S, the workpiece S tries to return by springback, but since the restraining die 33 is in contact, the workpiece S does not return by springback. After that, as shown in FIG. 10(a), while the restraining die 33 is in contact with the workpiece S, the bending die 21 and the clamping die 22 are rotated in the opposite direction to return to their original positions, and the pressure die 23 is also returned to its original position. In this way, the bending process at the initial bending position is completed.

[0058] After the bending process at the first bending position is completed, the workpiece S is moved in the feed direction as shown in FIG. 10(b) to position the next bending position relative to the position between the bending die 21 and the clamping die 22. Since the constraining die 33 remains in contact with the workpiece S, the constraining die 33 is also moved in the feed direction in accordance with the movement of the workpiece S in the feed direction. This prevents the constraining die 33 from leaving long scratches on the surface of the workpiece S when the workpiece S is moved in the feed direction. When changing the bending direction of the workpiece S, the workpiece S is rotated around its axis at this stage (i.e., with the constraining die 33 in contact with the workpiece S). For this reason, it is desirable that the end surface 33a of the constraining die 33 that comes into contact with the workpiece S is made of a slippery material or is subjected to a slippery surface treatment.

[0059] Next, as shown in FIG. 10(c), the clamping die 22 and the pressure die 23 are brought into contact with the workpiece S, and then the restraining die 33 is separated from the workpiece S. Then, the restraining die 33 is moved in the opposite direction to the feed direction to return the restraining die 33 to its original position (the position before the feed process begins). In parallel with this operation, the bending die 21 and the clamping die 22 are rotated in the bending direction and the pressure die 23 is moved in the feed direction to bend the workpiece S at a new bending position. FIG. 10(d) shows the state in which the workpiece S has been bent at the new bending position. After the bending process at the new bending position is thus completed, the above-mentioned return process is performed, and then the feed process is performed again to position the workpiece S so that the next new bending position is a predetermined position between the bending die 21 and the clamping die 22. By performing this series of processes for all bending positions set on the workpiece S, the workpiece S can be bent into a desired shape.

[0060] As described above, in the bending apparatus 1 of the second embodiment, the constraint die 33 is brought into contact with the workpiece S before the clamping die 22 and the pressure die 23 are separated from the workpiece S in the return step, so that the constraint die 33 can receive the force of the workpiece S trying to return due to spring back. Therefore, the articulated robot 40 having the chuck 30 attached to its tip is not subjected to the force due to the spring back of the workpiece S. As a result, it is possible to use a small articulated robot 40 that is small enough to transport the workpiece S.

[0061] Furthermore, in the bending apparatus 1 of the first embodiment described above, the bearing portion 31 on the main body case 10 moves in one direction until bending is completed at all bending positions on the workpiece S, whereas in the bending apparatus 1 of the second embodiment, the constraint mold 33 on the main body case 10 can be returned to its original position each time bending is completed at one bending position. Therefore, in the bending apparatus 1 of the second embodiment, the length of the main body case 10 in the feed direction can be made shorter than in the bending apparatus 1 of the first embodiment, making it possible to make the bending apparatus 1 even more compact.

[0062] The bending apparatus 1 of the first and second embodiments has been described above, but the present invention is not limited to the above embodiments and can be embodied in various forms without departing from the spirit of the present invention.

[0063] For example, the chuck 30 in the first and second embodiments described above has been described as gripping the workpiece S with the chuck jaws 30b from the end face side of the workpiece S. However, it is sufficient for the chuck 30 to grip one end side of the workpiece S, and for example, similar to the case where the hand portion 47 and hand jaws 47a in the first embodiment grip the gripped portion 30d, the chuck 30 may grip one end side of the workpiece S with the chuck jaws 30b from the side of the workpiece S. [Explanation of symbols]

[0064] 1... bending device, 10... main body case, 11... guide rail, 20... bending unit; 21... bending die; 21a... bending side surface; 21b... holding side surface, 22... clamping die, 22a... end surface, 22b... actuator; 23... pressure type; 23a... end surface; 23b... actuator; 24... rotating base; 25... pressure base; 26: drive unit; 30: chuck; 30a: chuck body; 30b... chuck jaws, 30c... chuck shaft, 30d... gripped portion, 31...bearing portion, 31a...guide portion, 33...restraint type, 33a...end surface, 33b... actuator; 34... moving base; 40... multi-joint robot; 41...base, 42...body, 43...first arm, 44...second arm, 45...third arm portion, 46...fourth arm portion, 47...hand portion, 47a...hand claw; 50...control section; 60...power supply section; S...workpiece, CL...center axis.

Claims

1. A bending apparatus (1) for bending a metal workpiece having a long shape and a predetermined number of bending positions, comprising: A chuck (30) for gripping one end side of the workpiece; an articulated robot (40) that moves the chuck that holds the workpiece; A bending die (21) having a bending side surface (21a) formed in a circumferential shape and a holding side surface (21b) formed in a linear shape continuous with the bending side surface; a clamping die (22) that is provided opposite the holding side surface of the bending die and that can hold the workpiece between the clamping die and the holding side surface by moving toward the holding side surface; a die rotation unit (26) that rotates the bending die and the clamping die in a predetermined bending direction around a central axis of the circumferential shape of the bending side surface; A pressure die (23) provided at a position adjacent to the chuck side with respect to the clamping die and movable in a direction parallel to a direction in which the clamping die approaches the holding side surface before the rotation; a control unit (50) for controlling the operations of the chuck, the articulated robot, the clamping die, the die rotating unit, and the pressure die; Equipped with The control unit is A feed control that uses the articulated robot to move the position of the chuck in the axial direction of the workpiece so that one of the bending positions on the workpiece is positioned relative to the holding side surface of the bending die and the clamping die; When the feed control is completed, the clamping die is brought close to the holding side surface to hold the workpiece between the holding side surface and the clamping die, and the pressure die is moved to abut against the workpiece, and the bending die and the clamping die are rotated in the bending direction using the die rotation unit to bend the workpiece. When the bending control is completed, the pressure die and the clamping die are separated from the workpiece, and the die rotating unit rotates the bending die and the clamping die in a direction opposite to the bending direction, thereby returning the bending die and the clamping die to their positions before the bending process. a control unit that repeatedly executes the above a number of times corresponding to the number of bending positions, At least during the return control and the feed control, a movement restraining section (31, 33) is mounted which moves in the axial direction together with the workpiece while restraining the movement of the workpiece toward the pressure die by contacting the chuck or the workpiece. A bending apparatus characterized by the above.

2. The bending apparatus according to claim 1, The movement restraining portion restrains the movement of the workpiece while allowing the workpiece to rotate around its axis. A bending apparatus characterized by the above.

3. The bending apparatus according to claim 2, The chuck is The workpiece is gripped from the direction of the end face of the workpiece, The chuck has a chuck shaft (30c) formed coaxially with the gripped workpiece, The movement constraint portion (31) is attached to the chuck shaft in a state in which it can rotate around the axis of the chuck shaft but cannot move in the axial direction, The articulated robot comprises: The chuck shaft is moved in an axial direction to move the workpiece in the axial direction of the workpiece; The chuck shaft is rotated about its axis, thereby rotating the workpiece about its axis. A bending apparatus characterized by the above.

4. The bending apparatus according to claim 1 or 2, the movement restraining portion restrains the movement of the workpiece toward the pressure die by contacting the workpiece at a position between the chuck and the pressure die, The control unit performs control to move the movement constraint unit away from the workpiece during the bending control until the bending control is terminated, and to return the movement constraint unit, which has been moved together with the workpiece during the feed control, to a position before the movement. A bending apparatus characterized by the above.

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