Bending machine

Abstract

To improve pass-through accuracy in bending, by deforming a bead beam into an ideal shape.SOLUTION: A bending machine 1 comprises a bend beam 30 that bends a work-piece W gripped by a bottom die 15 and a top die 25, along a bending line extending in a lateral direction, and a back-and-forth moving mechanism 50 that deforms the bend beam 30 in a longitudinal direction. The back-and-forth moving mechanism 50 has a central linearly moving part 50M that moves the bend beam 30 in the longitudinal direction along a central driving shaft AM, and a left linearly moving part 50L that moves the bend beam 30 in the longitudinal direction along a left driving shaft AL that is parallel to the central driving shaft AM. The bend beam 30 comprises a cut-off part 37n provided between the central driving shaft AM and the left driving shaft AL and formed to cut off a portion of the bend beam 30.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a bending machine.

Background Art

[0002] A bending machine includes an upper frame to which a top die is attached in the left - right direction, a lower frame to which a bottom die is attached in the left - right direction, and a bend beam provided behind the lower frame. The front end of the bend beam extends in the left - right direction, and bending dies are mounted along the left - right direction on the upper front side and the lower front side of the bend beam. The bend beam can move in the vertical direction and the front - rear direction by a vertical movement mechanism and a front - rear movement mechanism.

[0003] When performing bending, the work is fixed by clamping the work between the top die and the bottom die. When the bend beam operates in the vertical direction, the bending die is pressed against the end of the work protruding rearward from the rear ends of the top die and the bottom die. As a result, the end of the work is bent along a bending line extending in the left - right direction.

[0004] Patent Document 1 discloses a configuration in which the bend beam is moved in the front - rear direction by moving three bend beam arms connected to the bend beam in the front - rear direction. The three bend beam arms can move independently by movement mechanisms provided on each bend beam arm.

[0005] The bending machine of Patent Document 1 can perform crowning in which the bend beam is curved in the front - rear direction by independently controlling each drive mechanism. For example, when the bend beam is curved by the bending force of the work, by this crowning, the bend beam is adjusted to be positioned on a straight line (bending line) in the left - right direction. As a result, the bending of the bend beam is suppressed, so that the bend beam becomes straight, and the accuracy can be improved as per the bending process.

Prior Art Documents

Patent Document

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, since a high bending load acts on the bending beam, it is composed of a rigid body. For this reason, it is difficult to deform the bending beam into an ideal shape.

Means for Solving the Problems

[0008] One aspect of one or more embodiments is a bending machine including a bending beam that bends a work sandwiched between a lower bottom die and an upper top die along a bending line extending in the left-right direction, and a crowning mechanism that curves the bending beam in the front-rear direction. The crowning mechanism includes a first driving unit that moves the bending beam in the front-rear direction along a first driving shaft extending in the front-rear direction, and a second driving unit that is arranged at a distance from the first driving unit in the left-right direction and moves the bending beam in the front-rear direction along a second driving shaft parallel to the first driving shaft. The bending beam is provided between the first driving shaft and the second driving shaft and includes a first notch formed so as to notch a part of the bending beam.

Effects of the Invention

[0009] According to the bending machine according to one or more embodiments, since the bending beam can be deformed into an ideal shape, the accuracy can be improved as required by the bending process.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0011] Hereinafter, with reference to the drawings, the bending machine according to the present embodiment will be described. In the present embodiment, the structure of the bending machine is defined using the left - right direction, the front - rear direction, and the up - down direction. In the present embodiment, the left - right direction and the front - rear direction correspond to two orthogonal directions in the horizontal direction, and the up - down direction corresponds to the vertical direction, but it is not limited thereto. In the drawings, the right direction, the left direction, the up direction, the down direction, the front direction, and the rear direction are indicated by RT, LT, UP, DN, FR, and RR, respectively.

[0012] Figure 1 is a top view showing the main part of the bending machine 1 according to the present embodiment. Figure 2 is a side view showing the main part of the bending machine 1 according to the present embodiment.

[0013] As shown in Figure 2, the bending machine 1 is a processing machine that processes the work W into a desired shape by bending the processing area Wp of the plate - shaped work W, and is called a panel bender. In front of the bending machine 1, a manipulator (not shown) for supplying and positioning the work W is arranged.

[0014] The bending machine 1 mainly consists of a main body frame 5, a lower frame 10, an upper frame 20, a bend beam 30, a vertical movement mechanism 40, and a front-rear movement mechanism 50. In FIG. 1, the description of the workpiece W and the upper frame 20 is omitted.

[0015] The main body frame 5 is a frame that supports the lower frame 10, the upper frame 20, and the bend beam 30.

[0016] The lower frame 10 is formed horizontally in the left-right direction and is provided on the front side of the main body frame 5. A bottom die 15 as a fixed die is attached to the upper part of the lower frame 10. The bottom die 15 extends in the left-right direction along the lower frame 10.

[0017] The upper frame 20 is formed horizontally in the left-right direction. A top die 25 as a movable die, which faces the bottom die 15, is attached to the lower part of the upper frame 20. The top die 25 extends in the left-right direction along the upper frame 20.

[0018] The upper frame 20 is provided on the main body frame 5 so as to be movable in the vertical direction and moves in the vertical direction by a frame movement mechanism (not shown). When the upper frame 20 moves downward, the workpiece W is clamped by the bottom die 15 and the top die 25, so the workpiece W is fixed. Conversely, when the upper frame 20 moves upward, the top die 25 is separated from the workpiece W, so the fixing of the workpiece W is released.

[0019] The bend beam 30 is arranged behind the lower frame 10. The bend beam 30 has a substantially C-shaped cross-sectional shape with an open front side and extends in the left-right direction. A bending die 31 for forward bending, which bends the processing area Wp of the workpiece W upward, is mounted on the lower front side of the bend beam 30. A bending die 32 for reverse bending, which bends the processing area Wp of the workpiece W downward, is mounted on the upper front end of the bend beam 30. The detailed configuration of the bend beam 30 will be described later.

[0020] The bending beam 30 is configured to be movable in the front - rear direction and the up - down direction by an up - down movement mechanism 40 and a front - rear movement mechanism 50.

[0021] The up - down movement mechanism 40 is a mechanism for moving the bending beam 30 in the up - down direction. As shown in FIG. 1, the up - down movement mechanism 40 is composed of a left elevating part 40L and a right elevating part 40R. The left elevating part 40L is arranged on the left side of the main body frame 5 and supports the left region of the bending beam 30 from below. The right elevating part 40R is arranged on the right side of the main body frame 5 and supports the right region of the bending beam 30 from below.

[0022] Referring to FIG. 2, the configuration of the right elevating part 40R will be described. The configuration of the left elevating part 40L is the same. The right elevating part 40R includes a crankshaft (eccentric shaft) that rotates about a rotation axis extending in the left - right direction, and an electric motor 41 that rotationally drives the crankshaft. The eccentric part provided on the crankshaft and the bending beam 30 are connected by a connecting beam 42. The right elevating part 40R moves the bending beam 30 in the up - down direction by the rotation of the crankshaft driven by the electric motor 41.

[0023] Referring to FIG. 1, the left and right elevating parts 40L, 40R are controlled by a control device (not shown) and operate independently. The left and right elevating parts 40L, 40R can move the bending beam 30 in the up - down direction with the left and right heights of the bending beam 30 being the same, that is, in a horizontal state. Also, the left and right elevating parts 40L, 40R can switch the bending beam 30 to a state inclined from the horizontal plane by making one of the left and right sides of the bending beam 30 relatively lower than the other side.

[0024] The front-back movement mechanism 50 is a mechanism that moves the bend beam 30 in the front-back direction. Further, the front-back movement mechanism 50 is also a crowning mechanism that deforms the bend beam 30 in the front-back direction. Hereinafter, the operation of deforming the bend beam 30 in the front-back direction, that is, the operation of shifting a part of the bend beam 30 in the front-back direction with respect to a straight line extending in the left-right direction, is called crowning. However, the term crowning includes not only the operation of curving the bend beam 30 in the front-back direction in a state parallel to the straight line extending in the left-right direction, but also the operation of deforming the bend beam 30 curved in the front-back direction into a state parallel to the straight line extending in the left-right direction.

[0025] The front-back movement mechanism 50 is composed of a left linear movement part 50L, a central linear movement part 50M, and a right linear movement part 50R. The left, central, and right linear movement parts 50L, 50M, 50R are arranged at regular intervals in the left-right direction behind the bend beam 30. The left linear movement part 50L is arranged on the left side of the main body frame 5 and is connected to the left side of the bend beam 30. The central linear movement part 50M is arranged at the center of the main body frame 5 and is connected to the center of the bend beam 30. The right linear movement part 50R is arranged on the right side of the main body frame 5 and is connected to the right side of the bend beam 30.

[0026] FIG. 3 is a side view showing the configuration of the right linear movement part 50R. Hereinafter, with reference to FIG. 3, the configuration of the right linear movement part 50R will be described. The right linear movement part 50R includes an electric motor 52, a speed reducer 53, a ball screw shaft 54, a ball screw nut 56, and a yoke 57. The right linear movement part 50R is mounted on a plate-shaped base member 58 fixed to the upper surface (omitted in FIG. 3) of the main body frame 5.

[0027] The electric motor 52 is a device that generates torque by electric energy and is, for example, a servo motor. The speed reducer 53 decelerates and outputs the rotational power (torque) of the electric motor 52. A timing belt (not shown) is stretched between the output shaft of the electric motor 52 and the input shaft of the speed reducer 53, and the torque of the electric motor 52 is transmitted to the input shaft of the speed reducer 53 via the timing belt.

[0028] The ball screw shaft 54 and the ball screw nut 56 constitute a ball screw mechanism, which converts the rotational motion caused by the torque of the speed reducer 53 into a linear motion along the front-rear direction. The ball screw shaft 54 is arranged along the right drive shaft AR extending in the front-rear direction and is rotatably supported by a bearing 55. The rear end of the ball screw shaft 54 is connected to the output shaft of the speed reducer 53. The ball screw nut 56 is screwed onto the ball screw shaft 54 and is a linear motion member that moves linearly along the right drive shaft AR as the ball screw shaft 54 rotates forward and backward. This ball screw nut 56 is connected to a yoke 57.

[0029] The yoke 57 moves back and forth along the right drive shaft AR in response to the linear motion of the ball screw nut 56. The back-and-forth movement of the yoke 57 is guided by a guide rail 58a provided along the front-rear direction on the upper surface of the base member 58. The yoke 57 undergoes a simple linear motion along the front-rear direction and does not involve movement in other directions. The front end of the yoke 57 is bifurcated (see FIG. 1) and is connected to the bend beam 30.

[0030] The right linear motion part 50R can move the bend beam 30 in the front-rear direction by a ball screw mechanism that moves linearly along the right drive shaft AR.

[0031] The configurations of the left and central linear motion parts 50L and 50M are the same as that of the right linear motion part 50R. As shown in FIG. 1, the left linear motion part 50L can move the bend beam 30 in the front-rear direction by a linear motion along the left drive shaft AL extending in the front-rear direction. Similarly, the central linear motion part 50M can move the bend beam 30 in the front-rear direction by a linear motion along the central drive shaft AM extending in the front-rear direction.

[0032] The left, central, and right linear moving parts 50L, 50M, and 50R are controlled by a control device (not shown) and operate independently. The left, central, and right linear moving parts 50L, 50M, and 50R can move the bending beam 30 in the front-rear direction in a state where the front end of the bending beam 30 is parallel to a straight line extending in the left-right direction. Further, the left, central, and right linear moving parts 50L, 50M, and 50R can perform crowning of the bending beam 30.

[0033] Specifically, the left, central, and right linear moving parts 50L, 50M, and 50R can bend the bending beam 30 such that both the left and right sides of the bending beam 30 are located behind or in front of the center of the bending beam 30. Further, the left, central, and right linear moving parts 50L, 50M, and 50R can bend the bending beam 30 such that one of the left and right sides of the bending beam 30 is located behind or in front of the center of the bending beam 30. In addition, the left, central, and right linear moving parts 50L, 50M, and 50R can also bend the other of the left and right sides of the bending beam 30 in the opposite direction while one of the left and right sides of the bending beam 30 is bent forward or backward.

[0034] In the bending machine 1 having such a configuration, the bending process for the workpiece W is performed as follows. That is, the control device controls the manipulator to place the workpiece W on the top die 25 and position the workpiece W. As shown in FIG. 2, for the positioned workpiece W, the processing area Wp protrudes rearward from the rear end of the bottom die 15. At this time, the bending line is parallel to the left-right direction and coincides with the rear end of the bottom die 15. The control device drives the frame moving mechanism to lower the upper frame 20. When the upper frame 20 is lowered, the workpiece W is fixed by being clamped between the bottom die 15 and the top die 25.

[0035] Next, the control device moves the bending beam 30 in the front-rear direction and the up-down direction by controlling the up-down movement mechanism 40 and the front-rear movement mechanism 50. The bending beam 30 moves forward to a position where the processing area Wp of the workpiece W can be bent, and then moves in the up-down direction such that the front end side of the bending beam 30 draws an arc. When the bending beam is moved upward, the bending die 31 for normal bending pushes up the processing area Wp upward, and thus, normal bending can be performed on the processing area Wp. Conversely, when the bending beam is moved downward, the bending die 32 for reverse bending pushes down the processing area Wp downward, and thus, reverse bending can be performed on the processing area Wp.

[0036] Also, the control device can perform crowning of the bending beam 30 by controlling the front-rear movement mechanism 50 at a necessary timing prior to the bending process or during the bending process.

[0037] Hereinafter, with reference to FIG. 4, the structure of the bending beam 30 will be described. FIG. 4 is a perspective view showing the structure of the bending beam 30. The bending beam 30 is composed of a plurality of ribs 35, a lower bending frame 36, and an upper bending frame 37.

[0038] The plurality of ribs 35 are arranged in the left-right direction. Each rib 35 has a C-shaped cross-sectional shape with an opening, and is arranged such that the opening faces forward. Each rib 35 imparts rigidity against the high load acting during the bending process to the lower bending frame 36 and the upper bending frame 37.

[0039] In the present embodiment, a total of seven ribs 35 are arranged. One rib 35 is arranged at the center of the bending beam 30, and three ribs 35 are arranged in the left region of the bending beam 30. Also, three ribs 35 are arranged in the right region of the bending beam 30.

[0040] When showing the central rib 35, it is denoted as rib 35M. When showing each rib 35 in the left region, they are denoted as rib 35LL, 35LM, and 35LR in order from the left. When showing each rib 35 in the right region, they are denoted as rib 35RL, 35RM, and 35RR in order from the left.

[0041] Among the seven ribs 35, for any rib 35, a connecting block 38 for connecting the forward and backward movement mechanism 50 and the bend beam 30 is attached. In this embodiment, a total of three connecting blocks 38 are attached. Specifically, the connecting block 38 is attached to the central rib 35M. Among the three ribs 35LL, 35LM, and 35LR in the left region of the bend beam 30, the connecting block 38 is attached to the central rib 35LM. Among the three ribs 35RL, 35RM, and 35RR in the right region of the bend beam 30, the connecting block 38 is attached to the central rib 35RM.

[0042] As shown in FIG. 1, the left, central, and right linear motion parts 50L, 50M, and 50R are connected to the ribs 35LM, 35M, and 35RM via the connecting blocks 38 respectively. Specifically, the left linear motion part 50L is connected to the rib 35LM. The central linear motion part 50M is connected to the rib 35M. The right linear motion part 50R is connected to the rib 35RM.

[0043] As shown in FIG. 4, the lower bend frame 36 extends in the left - right direction and is supported by a plurality of ribs 35. At the front end 36f of the lower bend frame 36, a bending die 31 for positive bending is mounted. On the lower surface of the lower bend frame 36, a support part 36a for rotatably supporting the connecting beam 42 (see FIG. 2) of the up - and - down movement mechanism 40 is provided.

[0044] The upper bend frame 37 extends in the left - right direction and is supported by a plurality of ribs 35. At the front end 37f of the upper bend frame 37, a bending die 32 for reverse bending is mounted.

[0045] FIG. 5 is a diagram for explaining the structure of the upper bend frame 37. A plurality of notches 37n are provided at the rear end 37r of the upper bend frame 37. In the example shown in FIG. 5, a total of four notches 37n are provided.

[0046] Two notches 37n are provided between the rib 35M to which the central linear motion part 50M is connected and the rib 35LM to which the left linear motion part 50L is connected. The two notches 37n are respectively arranged on the left side and the right side with the rib 35LR where the left and central linear motion parts 50M, 50L are not connected as a boundary.

[0047] Two notches 37n are provided between the rib 35RM to which the right linear motion part 50R is connected and the rib 35M to which the central linear motion part 50M is connected. The two notches 37n are respectively arranged on the left side and the right side with the rib 35RL where the central and right linear motion parts 50M, 50R are not connected as a boundary.

[0048] Each notch 37n has a curved shape that is concave and recessed forward. The curved shape of each notch 37n is configured by combining a radius of curvature Ra and a radius of curvature Rb smaller than this radius of curvature Ra. The larger radius of curvature Ra is set on the side of the ribs 35LM, 35M, 35RM to which the linear motion parts 50L, 50M, 50R are connected, and the smaller radius of curvature Rb is set on the side of the ribs 35LR, 35RL where the linear motion parts 50L, 50M, 50R are not connected. For example, taking the notch 37n between the rib 35M to which the central linear motion part 50M is connected and the rib 35RL on its right side as an example. In this case, in the notch 37n, the region on the rib 35M side is curved with the larger radius of curvature Ra, and the region on the rib 35RL side is curved with the smaller radius of curvature Rb.

[0049] In the bend beam 30 according to the present embodiment, when the left, center, and right linear motion parts 50L, 50M, and 50R are driven, the ribs 35LM, 35M, and 35RM connected thereto move relatively in the front-rear direction. At this time, the bend beam 30 bends in the front-rear direction according to the relative positions of the ribs 35LM, 35M, and 35RM in the front-rear direction. For example, when the ribs 35LM and 35RM in the left and right regions move relatively rearward compared to the central rib 35M, the bend beam 30 bends so that the center becomes convex forward. Alternatively, when the rib 35LM in the left region moves relatively rearward compared to the ribs 35M and 35RM in the central and right regions, the bend beam 30 bends so that the left region faces rearward.

[0050] When the bend beam 30 bends due to crowning, stress concentrates on the upper bend frame 37. In particular, between the ribs 35LM, 35M, and 35RM to which the left, center, and right linear motion parts 50L, 50M, and 50R are connected, the upper bend frame 37 bends greatly, so high stress is generated. As described above, two notches 37n are provided between the ribs 35LM and 35M connected to the left and central linear motion parts 50L and 50M, and two notches 37n are provided between the ribs 35M and 35RM connected to the central and right linear motion parts 50M and 50R. These notches 37n can allow the upper bend frame 37 to bend in the front-rear direction and can suppress stress concentration between the ribs 35LM, 35M, and 35RM.

[0051] Also, in the vicinity of the ribs 35LM, 35M, and 35RM to which the left, center, and right linear motion parts 50L, 50M, and 50R are connected, stress concentration becomes remarkable in order to bend the bend beam 30. In this regard, a large radius of curvature Ra is set on the side of the ribs 35LM, 35M, and 35RM for each notch 37n. Thereby, it is possible to suppress stress concentration in the vicinity of the ribs 35LM, 35M, and 35RM.

[0052] In Fig. 5, the structure of the rear end 37r of the upper bend frame 37 was described. The structure of the rear end 36r of the lower bend frame 36 is the same. That is, as shown in Fig. 4, a plurality of notches 36n are provided at the rear end 36r of the lower bend frame 36. In the present embodiment, a total of four notches 36n are also provided between the ribs 35LM, 35M, and 35RM to which the left, center, and right linear motion parts 50L, 50M, and 50R are connected at the rear end 36r of the lower bend frame 36.

[0053] Referring to Figs. 6 and 7, the connection structure between the bend beam 30 and the left, center, and right linear motion parts 50L, 50M, and 50R will be described. Fig. 6 is a cross-sectional view showing the connection structure between the center linear motion part 50L and the connection block 38, and Fig. 7 is a cross-sectional view showing the connection structure between the right linear motion part 50R and the connection block 38.

[0054] As shown in Fig. 6, a support shaft 39 extending in the left-right direction is provided at the front end of the yoke 57 in the center linear motion part 50M. An automatic aligning roller bearing 60 that supports the support shaft 39 is provided at the rear end of the connection block 38. As shown in Fig. 7, the connection structure in the right linear motion part 50R is the same. A support shaft 39 extending in the left-right direction is provided at the front end of the yoke 57. An automatic aligning roller bearing 60 that supports the support shaft 39 is provided at the rear end of the connection block 38. Note that the connection structure in the left linear motion part 50L is the same, and the description thereof is omitted.

[0055] As shown in Figs. 6 and 7, in a state where no crowning is performed, the connection block 38 is in a reference state along the reference line La extending in the front-rear direction. On the other hand, when the bend beam 30 is curved by crowning, the connection block 38 also tilts so as to be inclined with respect to the reference line La. At this time, the automatic aligning roller bearing 60 can allow the inclination of the connection block 38. Thereby, while suppressing the generation of a large load on the connection part, the bend beam 30 can be appropriately curved.

[0056] In addition, as shown in FIG. 7, in the left and right linear motion parts 50L and 50R, a clearance in the left-right direction is provided between the self-aligning roller bearing 60 and the yoke 57. The self-aligning roller bearing 60 can move in the left-right direction by the amount of this clearance. Thereby, when the bend beam 30 is curved by crowning, the connecting block 38 can be allowed to move in the left-right direction. Thereby, the bend beam 30 can be appropriately curved.

[0057] On the other hand, as shown in FIG. 6, in the central linear motion part 50M, a collar 61 is provided between the self-aligning roller bearing 60 and the yoke 57. The movement of the self-aligning roller bearing 60 in the left-right direction is restricted by this collar 61. At the central position of the bend beam 30, by restricting the movement of the connecting block 38 in the left-right direction, it is possible to restrict the bend beam 30 from being displaced in the left-right direction.

[0058] As described above, the bending machine 1 according to the present embodiment includes a bend beam 30 that bends a workpiece W sandwiched between a bottom die 15 and a top die 25 along a bending line extending in the left-right direction, and a front-rear movement mechanism (crowning mechanism) 50 that deforms the bend beam 30 in the front-rear direction. The front-rear movement mechanism 50 includes a central linear motion part (first drive part) 50M that moves the bend beam 30 in the front-rear direction along a central drive shaft (first drive shaft) AM extending in the front-rear direction, and a left linear motion part (second drive part) 50L that is arranged at a distance from the central linear motion part 50M in the left-right direction and moves the bend beam 30 in the front-rear direction along a left drive shaft (second drive shaft) AL parallel to the central drive shaft AM. The bend beam 30 is provided between the central drive shaft AM and the left drive shaft AL, and includes cutout parts (first cutout parts) 36n and 37n formed so as to cut out a part of the bend beam 30.

[0059] Since the bending beam 30 bends significantly between the left linear motion part 50L and the central linear motion part 50M, high stress is generated. The notches 36n and 37n provided in the bending beam 30 can suppress the concentration of stress at the curved part of the bending beam 30. In addition, since the bending beam 30 is more likely to bend, the bending beam 30 can be deformed significantly. As a result, the bending beam 30 can be deformed into an ideal shape, so that the accuracy can be improved as in the bending process.

[0060] In the present embodiment, the front-rear movement mechanism 50 is arranged at a position facing the left linear motion part 50L with the central linear motion part 50M in between, and further has a right linear motion part (third drive part) 50R that moves the bending beam 30 in the front-rear direction along a right drive shaft (third drive shaft) AR parallel to the central drive shaft AM. The bending beam 30 is provided between the central drive shaft AM and the right drive shaft AR, and further includes notches (second notches) 36n and 37n formed so as to cut out a part of the bending beam 30.

[0061] According to this configuration, the left, central, and right linear motion parts 50L, 50M, and 50R are connected to the bending beam 30. By moving the bending beam 30 in the front-rear direction by the three drive shafts AL, AM, and AR, the bending beam 30 can be deformed into an arbitrary shape.

[0062] Also, since the bending beam 30 bends significantly between the central linear motion part 50M and the right linear motion part 50R, high stress is generated. The notches 36n and 37n provided in the bending beam 30 can suppress the concentration of stress at the curved part of the bending beam 30. In addition, since the bending beam 30 is more likely to bend, the bending beam 30 can be deformed significantly. As a result, the bending beam 30 can be deformed into an ideal shape, so that the accuracy can be improved as in the bending process.

[0063] In this embodiment, the left, center, and right linear motion parts 50L, 50M, and 50R move the bend beam 30 in the front-rear direction by a ball screw mechanism (linear motion mechanism) that linearly moves along the left, center, and right third drive shafts AL, AM, and AR. The front-rear movement mechanism 50 deforms the bend beam 30 in the front-rear direction by independently driving the left, center, and right third drive shafts AL, AM, and AR respectively.

[0064] As a mechanism for moving the bend beam 30 in the front-rear direction, a method using an eccentric shaft that rotates about a rotation shaft extending in the left-right direction can be considered. However, in the case of a configuration using an eccentric shaft, the eccentric shaft includes not only a movement component in the front-rear direction but also a movement component in the up-down direction. For this reason, there is a risk that the bend beam 30 will be twisted in the up-down direction, resulting in a decrease in accuracy as in the bending process.

[0065] According to this embodiment, the bend beam 30 is moved in the front-rear direction only by the linear motion along the left, center, and right third drive shafts AL, AM, and AR. It is possible to suppress the occurrence of twisting in the up-down direction in the bend beam 30 as in the case of using an eccentric shaft, so that the accuracy can be improved as in the bending process.

[0066] Also, in the case of a configuration using an eccentric shaft, the maximum value of the movement amount of the bend beam 30 in the front-rear direction is the eccentricity of the eccentric shaft. In this embodiment, since it is a linear motion mechanism, a large movement amount of the bend beam 30 in the front-rear direction can be ensured. Thereby, the bend beam 30 can be largely deformed. However, in the case of a linear motion mechanism, it is required to suppress that the bend beam 30 has a structure that is easily bent and that stress concentrates on the curved portion of the bend beam 30. In this embodiment, while adopting a linear motion mechanism, by providing the notch portions 36n and 37n in the bend beam 30 as described above, the bend beam 30 is made easy to bend and the concentration of stress on the curved portion is suppressed. In this way, by largely deforming the bend beam 30 by the linear motion mechanism, the object of deforming the bend beam 30 into an ideal shape is achieved.

[0067] In the present embodiment, a ball screw mechanism is exemplified as the linear motion mechanism, but the present invention is not limited thereto. The left, center, and right drive shafts AL, AM, and AR can widely utilize linear actuators.

[0068] In the present embodiment, the bend beam 30 is equipped with a bending die 31 for positive bending that bends the workpiece W upward, and a lower bend frame 36 that extends in the left - right direction, and a bending die 32 for reverse bending that bends the workpiece W downward, and an upper bend frame that extends in the left - right direction. The notch portions 36n, 37n are provided in the lower and upper bend frames 36, 37 respectively.

[0069] According to this configuration, the notch portions 36n, 37n are provided in the lower and upper bend frames 36, 37 which are rigid bodies extending in the left - right direction. Therefore, it is possible to suppress stress concentration at the curved portions of the lower and upper bend frames 36, 37. In addition, since the lower and upper bend frames 36, 37 are easily bent, the lower and upper bend frames 36, 37 can be greatly deformed. Thereby, the bend beam 30 can be deformed into an ideal shape, so that the accuracy can be improved as in the bending process.

[0070] In the present embodiment, the bend beam 30 further includes a plurality of ribs 35 that are arranged at intervals in the left - right direction and reinforce the lower and upper bend frames 36, 37. The left, center, and right linear motion portions 50L, 50M, 50R are connected to three ribs 35 selected from the plurality of ribs 35.

[0071] Specifically, as shown in FIG. 4, the plurality of ribs 35 include a rib (first rib) 35M disposed at the center of the bend beam 30 to which the central linear motion portion 50M is connected, and a rib (second rib) 35LM disposed in the left region of the bend beam 30 to which the left linear motion portion 50L is connected. The plurality of ribs 35 also include a rib (third rib) 35RM disposed in the right region of the bend beam 30 to which the right linear motion portion is connected. Further, the plurality of ribs 35 include a rib (fourth rib) 35LR disposed between the central rib 35M and the rib 35LM in the left region, and a rib (fifth rib) 35RL disposed between the central rib 35M and the rib 35RM in the right region. The cutout portions 36n and 37n are provided between the rib 35M and the rib 35LR, and between the rib 35LR and the rib 35LM, respectively. Also, the cutout portions 36n and 37n are provided between the rib 35M and the rib 35RL, and between the rib 35RL and the rib 35RM, respectively.

[0072] Since the lower and upper bend frames 36 and 37 bend greatly between the respective ribs 35, high stress is generated. The cutout portions 36n and 37n provided in the lower and upper bend frames 36 and 37 can suppress stress concentration at the curved portions of the lower and upper bend frames 36 and 37. In addition, since the lower and upper bend frames 36 and 37 are more likely to bend, the lower and upper bend frames 36 and 37 can be greatly deformed. Thereby, the bend beam 30 can be deformed into an ideal shape, so that the accuracy can be improved as in bending.

[0073] In the present embodiment, the curved shape of the cutout portions 36n and 37n is configured by combining a first curvature radius Ra and a second curvature radius Rb smaller than the first curvature radius Ra. The first curvature radius Ra is set on the side of the ribs 35LM, 35M, and 35RM to which the linear motion portions 50L, 50M, and 50R are connected. On the other hand, the second curvature radius Rb is set on the side of the ribs 35LR and RL to which the linear motion portions 50L, 50M, and 50R are not connected.

[0074] In the vicinity of the ribs 35LM, 35M, and 35RM to which the linear motion parts 50L, 50M, and 50R are connected, since a load acts from the linear motion parts 50L, 50M, and 50R during crowning, stress concentration becomes remarkable. In this regard, a large radius of curvature Ra is set on the rib 35LM, 35M, 35RM side for each notch 36n, 37n. Thereby, it is possible to suppress stress from concentrating in the vicinity of the ribs 35LM, 35M, and 35RM.

[0075] In the above description, the shape of the notch 37n shown in FIG. 5 was exemplified. However, the shape of the notch 7n is merely an example, and the present embodiment is not limited thereto. Notches 37n1 to 37n7 having the shape shown in FIG. 8 may be provided at the rear end 37r of the upper bend frame 37. FIG. 8 is a diagram showing the shapes of the notches 37n1 to 37n7 of the upper bend frame 37 according to a modified example.

[0076] As shown in FIG. 8(a), the notch 37n1 has a semi-circular shape with a constant radius of curvature such that the center of curvature is located at the rear end 37r. As shown in FIG. 8(b), the notch 37n2 has a semi-oval shape in which an oval is divided in a direction orthogonal to the longitudinal direction. As shown in FIG. 8(c), the notch 37n3 has a semi-oval shape in which an oval is divided along the longitudinal direction. As shown in FIG. 8(d), the notch 37n4 has a shape in which a circular portion and a rectangular portion are combined. As shown in FIG. 8(e), the notch 37n5 has an arc shape with a constant radius of curvature such that the center of curvature is located outside the rear end 37r. As shown in FIG. 8(f), the notch 37n6 has a trapezoidal shape including a reference side parallel to the rear end 37r and a pair of symmetric inclined sides connected to this reference side. As shown in FIG. 8(g), the notch 37n7 has a shape in which semicircles arranged side by side on the left and right and a rectangular shape located at the boundary between the semicircles are combined.

[0077] Even with the cutouts 37n1 to 37n7 shown in these modified examples, it is possible to suppress stress concentration at the curved portion of the bend beam 30. In addition, since the bend beam 30 is more easily bent, the bend beam 30 can be greatly deformed. As a result, the bend beam 30 can be deformed into an ideal shape, so that the accuracy can be improved as in the bending process.

[0078] Although the modified example regarding the cutout 37n of the upper bend frame 37 has been described with reference to FIG. 8, this modified example is also applicable to the cutout 36n of the lower bend frame 36.

[0079] As described above, although this embodiment has been described, the descriptions and drawings forming a part of this embodiment should not be understood as limiting this embodiment. Various alternative embodiments, examples, and operation techniques will be apparent to those skilled in the art from this embodiment.

Explanation of Reference Numerals

[0080] 1 Bending machine 5 Main body frame 10 Lower frame 15 Bottom die 20 Upper frame 25 Top die 30 Bend beam 31, 32 Bending dies 35 Rib 36 Lower bend frame 36f Front end 36n Cutout 36r Rear end 37 Upper bend frame 37f Front end 37n Cutout 37r Rear end 38 Connecting block 39 Support shaft 40 Vertical movement mechanism 40L, 40R Lifting parts (left lifting part, right lifting part) 41 Electric motor 42 Connecting beam 50 Front-rear movement mechanism 50L, 50M, 50R linear motion parts (left linear motion part, central linear motion part, right linear motion part) 52 Electric motor 53 Reducer 54 Ball screw shaft 55 Bearing 56 Ball screw nut 57 Yoke 60 Self-aligning roller bearing AL, AM, AR drive shafts (left drive shaft, central drive shaft, right drive shaft) W Workpiece

Claims

1. A bending beam that bends a workpiece sandwiched between a bottom die and a top die along a bending line extending in the left - right direction, and a crowning mechanism that deforms the bending beam in the front - rear direction, wherein the crowning mechanism has a first driving part that moves the bending beam in the front - rear direction along a first driving shaft extending in the front - rear direction, a second driving part that is arranged at a distance from the first driving part in the left - right direction and moves the bending beam in the front - rear direction along a second driving shaft parallel to the first driving shaft, and a third driving part that is arranged at a position facing the second driving part with the first driving part in between and moves the bending beam in the front - rear direction along a third driving shaft parallel to the first driving shaft, wherein the bending beam has a first notch part that is provided between the first driving shaft and the second driving shaft and is formed so as to notch a part of the bending beam, and a second notch part that is provided between the first driving shaft and the third driving shaft and is formed so as to notch a part of the bending beam, a bending machine.

2. The first driving part, the second driving part, and the third driving part move the bending beam in the front - rear direction by a linear motion mechanism that moves linearly along the first driving shaft, the second driving shaft, and the third driving shaft, and the crowning mechanism deforms the bending beam in the front - rear direction by driving the first driving part, the second driving part, and the third driving part independently. The bending machine according to Claim 1.

3. The bending beam has a lower bending frame that extends in the left - right direction and is equipped with a bending die for positive bending that bends the workpiece upward, and an upper bending frame that extends in the left - right direction and is equipped with a bending die for reverse bending that bends the workpiece downward, wherein the first and second notch parts are respectively provided on the lower bending frame and the upper bending frame. The bending machine according to Claim 2.

4. The bending beam further includes a plurality of ribs that are arranged at intervals in the left - right direction and reinforce the lower bending frame and the upper bending frame, and the first driving part, the second driving part, and the third driving part are connected to three ribs selected from the plurality of ribs. The bending machine according to Claim 3.

5. The plurality of ribs include a first rib that is arranged at the center of the bending beam and to which the first driving part is connected, A second rib that is disposed in the left region of the bend beam and to which the second drive unit is connected; A third rib that is disposed in the right region of the bend beam and to which the third drive unit is connected; A fourth rib that is disposed between the first rib and the second rib; A fifth rib that is disposed between the first rib and the third rib, and includes: The first notch is provided between the first rib and the fourth rib and between the fourth rib and the second rib, respectively; The second notch is provided between the first rib and the fifth rib and between the fifth rib and the third rib, respectively. The bending machine according to claim 4.

6. The curved shapes of the first notch and the second notch are configured by combining a first radius of curvature and a second radius of curvature smaller than the first radius of curvature; The first radius of curvature is set on the rib side to which each drive unit is connected; The second radius of curvature is set on the rib side to which each drive unit is not connected. The bending machine according to claim 5.

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