Bending machine

Abstract

A bending machine (1) comprises: a bend beam (30) that bends a workpiece (W) held between a bottom die (15) and a top die (25) along a bending line extending in the left-and-right direction; and a back-and-forth movement mechanism (50) for deforming the bend beam (30) in the back-and-forth direction. The back-and-forth movement mechanism (50) has a middle linear motion part (50M) that moves the bend beam (30) in the back-and-forth direction along a middle drive axis (AM), and a left linear motion part (50L) that moves the bend beam (30) in the back-and-forth direction along a left drive axis (AL) parallel to the middle drive axis (AM). The bend beam (30) comprises cut-out parts (37n) that are formed so as to cut out portions of the bend beam (30) and that are provided between the middle drive axis (AM) and the left drive axis (AL).

Description

Bending machine

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

[0002] The 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 attached to the front upper and front lower parts of the bend beam along the left-right direction. The bend beam can be moved in the up-down direction and the front-back direction by a vertical movement mechanism and a front-back movement mechanism.

[0003] When bending, the workpiece is clamped between the top and bottom dies to hold it in place. When the bend beam moves up and down, the bending die is pressed against the end of the workpiece that protrudes rearward from the rear ends of the top and bottom dies. This bends the end of the workpiece along a bend line that extends left and right.

[0004] Patent Document 1 discloses a configuration in which three bend beam arms connected to the bend beam are moved in the forward and backward directions, and the three bend beam arms can be moved independently by a movement mechanism provided on each bend beam arm.

[0005] The bending machine of Patent Document 1 can perform crowning, which bends the bend beam in the front-to-rear direction, by independently controlling each drive mechanism. For example, if the bend beam is bent due to the bending force of the workpiece, this crowning adjusts the bend beam so that it is positioned on a straight line (bend line) in the left-to-right direction. This suppresses the bending of the bend beam, keeping it straight and improving the accuracy of the bending process.

[0006] Japanese Patent Application Laid-Open No. 2002-035846

[0007] However, because bend beams are subject to high bending loads, they are made of rigid materials, making it difficult to deform them into the ideal shape.

[0008] One aspect of one or more embodiments is a bending machine including a bend beam that bends a workpiece sandwiched between a lower bottom die and an upper top die along a bend line extending in the left-right direction, and a crowning mechanism that curves the bend beam in the front-rear direction. The crowning mechanism includes a first drive unit that moves the bend beam in the front-rear direction along a first drive shaft that extends in the front-rear direction, and a second drive unit that is disposed left-right apart from the first drive unit and moves the bend beam in the front-rear direction along a second drive shaft that is parallel to the first drive shaft. The bend beam is provided between the first drive shaft and the second drive shaft and includes a first notch formed to cut out a portion of the bend beam.

[0009] According to one or more embodiments of the bending machine, the bend beam can be deformed into an ideal shape, thereby improving the accuracy of the bending process.

[0010] FIG. 1 is a side view schematically showing the main parts of a bending machine according to this embodiment. FIG. 2 is a side view showing the main parts of the bending machine 1 according to this embodiment. FIG. 3 is a side view showing the configuration of the right linear motion unit. FIG. 4 is a perspective view showing the structure of the bend beam. FIG. 5 is a diagram explaining the structure of the upper bend frame. FIG. 6 is a cross-sectional view showing the connection structure between the central linear motion unit and the connecting block. FIG. 7 is a cross-sectional view showing the connection structure between the right linear motion unit and the connecting block. FIG. 8 is a diagram showing the shape of a cutout portion of the upper bend frame according to a modified example.

[0011] Hereinafter, a bending machine according to this embodiment will be described with reference to the drawings. In this embodiment, the structure of the bending machine is defined using the left-right direction, the front-rear direction, and the up-down direction. In this embodiment, the left-right direction and the front-rear direction correspond to two directions that are orthogonal to the horizontal direction, and the up-down direction corresponds to the vertical direction, but this 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] Fig. 1 is a top view showing a main part of a bending machine 1 according to this embodiment. Fig. 2 is a side view showing a main part of the bending machine 1 according to this embodiment.

[0013] 2, the bending machine 1 is a processing machine that processes a plate-shaped workpiece W into a desired shape by bending a processing region Wp of the workpiece W, and is called a panel bender. A manipulator (not shown) that supplies and positions the workpiece W is disposed in front of the bending machine 1.

[0014] The bending machine 1 is mainly composed of a main 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 workpiece W and the upper frame 20 are not shown.

[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 to be long in the left-right direction and is provided in front of the main frame 5. A bottom die 15 serving as a fixed mold 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 to be long in the left-right direction. A top die 25 serving as a movable mold is attached to the lower part of the upper frame 20, facing the bottom die 15. The top die 25 extends in the left-right direction along the upper frame 20.

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

[0019] The bend beam 30 is disposed behind the lower frame 10. The bend beam 30 has a generally C-shaped cross section that is open at the front side and extends in the left-right direction. A bending die 31 for normal bending that bends the processing area Wp of the workpiece W upward is attached to the front lower part of the bend beam 30. A bending die 32 for reverse bending that bends the processing area Wp of the workpiece W downward is attached to the front upper part of the bend beam 30. The detailed configuration of the bend beam 30 will be described later.

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

[0021] The vertical movement mechanism 40 is a mechanism for moving the bend beam 30 in the vertical direction. As shown in Figure 1, the vertical movement mechanism 40 is composed of a left lifting unit 40L and a right lifting unit 40R. The left lifting unit 40L is disposed on the left side of the main frame 5 and supports the left region of the bend beam 30 from below. The right lifting unit 40R is disposed on the right side of the main frame 5 and supports the right region of the bend beam 30 from below.

[0022] The configuration of the right lifting unit 40R will be described with reference to Figure 2, but the configuration of the left lifting unit 40L is the same. The right lifting unit 40R includes a crankshaft (eccentric shaft) that rotates about a rotation axis extending in the left-right direction, and an electric motor 41 that rotates the crankshaft. The eccentric portion of the crankshaft and the bend beam 30 are connected by a connecting beam 42. The right lifting unit 40R moves the bend beam 30 up and down by the rotation of the crankshaft driven by the electric motor 41.

[0023] 1, the left and right lifting units 40L, 40R are controlled by a control device (not shown) and operate independently. The left and right lifting units 40L, 40R can move the bend beam 30 up and down while the left and right sides of the bend beam 30 are at the same height, i.e., horizontally. The left and right lifting units 40L, 40R can also lower one side of the bend beam 30 relative to the other side, thereby switching the bend beam 30 to an inclined position relative to the horizontal plane.

[0024] The longitudinal movement mechanism 50 is a mechanism that moves the bend beam 30 in the longitudinal direction. The longitudinal movement mechanism 50 also functions as a crowning mechanism that deforms the bend beam 30 in the longitudinal direction. Hereinafter, the action of deforming (bending) the bend beam 30 in the longitudinal direction, i.e., the action of shifting a portion of the bend beam 30 in the longitudinal direction relative to a line extending in the left-right direction, will be referred to as "crowning." However, the term "crowning" is intended to include not only the action of curving the bend beam 30 in the longitudinal direction from a state parallel to a line extending in the left-right direction, but also the action of deforming the bend beam 30 that is curved in the longitudinal direction to a state parallel to a line extending in the left-right direction.

[0025] The forward / backward movement mechanism 50 is composed of a left linear motion unit 50L, a central linear motion unit 50M, and a right linear motion unit 50R. The left, central, and right linear motion units 50L, 50M, and 50R are arranged at regular intervals in the left-right direction behind the bend beam 30. The left linear motion unit 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 motion unit 50M is arranged in the center of the main body frame 5 and is connected to the center of the bend beam 30. The right linear motion unit 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] Figure 3 is a side view showing the configuration of the right linear motion unit 50R. The configuration of the right linear motion unit 50R will be described below with reference to Figure 3. The right linear motion unit 50R includes an electric motor 52, a reducer 53, a ball screw shaft 54, a ball screw nut 56, and a yoke 57. The right linear motion unit 50R is mounted on a plate-shaped base member 58 fixed to the upper surface of the main body frame 5 (not shown in Figure 3).

[0027] The electric motor 52 is a device, such as a servo motor, that generates torque using electrical energy. The reducer 53 reduces the rotational power (torque) of the electric motor 52 and outputs it. A timing belt (not shown) is stretched between the output shaft of the electric motor 52 and the input shaft of the reducer 53, and the torque of the electric motor 52 is transmitted to the input shaft of the 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 rotational motion due to the torque of the reducer 53 into linear motion along the front-to-rear direction. The ball screw shaft 54 ​​is disposed along the right drive shaft AR extending in the front-to-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 reducer 53. The ball screw nut 56 is threadedly engaged with 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. The ball screw nut 56 is connected to a yoke 57.

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

[0030] The right linear motion unit 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 left and central linear motion units 50L, 50M have the same configuration as the right linear motion unit 50R. As shown in Fig. 1, the left linear motion unit 50L can move the bend beam 30 in the front-rear direction by linear motion along a left drive shaft AL extending in the front-rear direction. Similarly, the central linear motion unit 50M can move the bend beam 30 in the front-rear direction by linear motion along a central drive shaft AM extending in the front-rear direction.

[0032] The left, center, and right linear actuators 50L, 50M, and 50R are controlled by a control device (not shown) and operate independently. The left, center, and right linear actuators 50L, 50M, and 50R can move the bend beam 30 in the front-rear direction while keeping the front end of the bend beam 30 parallel to a straight line extending in the left-right direction. The left, center, and right linear actuators 50L, 50M, and 50R can also crown the bend beam 30.

[0033] Specifically, the left, center, and right linear motion units 50L, 50M, and 50R can bend the bend beam 30 so that both the left and right sides of the bend beam 30 are positioned rearward or forward of the center of the bend beam 30. Furthermore, the left, center, and right linear motion units 50L, 50M, and 50R can bend the bend beam 30 so that one of the left and right sides of the bend beam 30 is positioned rearward or forward of the center of the bend beam 30. In addition, while one of the left and right sides of the bend beam 30 is bent forward or backward, the left, center, and right linear motion units 50L, 50M, and 50R can bend the other left and right side of the bend beam 30 in the opposite direction.

[0034] In the bending machine 1 configured as described above, bending of 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 , the positioned workpiece W has a processing region Wp that 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 lowers, the workpiece W is clamped between the bottom die 15 and the top die 25, thereby fixing the workpiece W.

[0035] Next, the control device controls the vertical movement mechanism 40 and the front-rear movement mechanism 50 to move the bend beam 30 in the front-rear and up-down directions. The bend beam 30 moves forward to a position where it can bend the processing area Wp of the workpiece W, and then the front end of the bend beam 30 moves up and down in an arc. When the bend beam is moved upward, the bending die 31 for normal bending pushes the processing area Wp upward, thereby enabling normal bending of the processing area Wp. Conversely, when the bend beam is moved downward, the bending die 32 for reverse bending pushes the processing area Wp downward, thereby enabling reverse bending of the processing area Wp.

[0036] Furthermore, the control device can crown the bend beam 30 by controlling the forward / backward movement mechanism 50 at a necessary timing, such as before the bending process or during the bending process.

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

[0038] The plurality of ribs 35 are arranged in the left-right direction. Each rib 35 has a C-shaped cross section with an opening, and is arranged so that the opening faces forward. Each rib 35 provides the lower bend frame 36 and the upper bend frame 37 with rigidity against high loads acting during bending.

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

[0040] The central rib 35 is referred to as rib 35M, and the ribs 35 in the left region are referred to as ribs 35LL, 35LM, and 35LR in order from the left. The ribs 35 in the right region are referred to as ribs 35RL, 35RM, and 35RR in order from the left.

[0041] As shown in FIG. 1 , a connecting block 38 for connecting the front-rear movement mechanism 50 and the bend beam 30 is attached to any of the seven ribs 35. In this embodiment, a total of three connecting blocks 38 are attached. Specifically, the connecting block 38 is attached to the central rib 35M. Of the three ribs 35LL, 35LM, and LR in the left region of the bend beam 30, the connecting block 38 is attached to the central rib 35LM. Of 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] The left, center, and right linear motion portions 50L, 50M, and 50R are connected to the ribs 35LM, 35M, and 35RM, respectively, via the connecting block 38. Specifically, the left linear motion portion 50L is connected to the rib 35LM. The center linear motion portion 50M is connected to the rib 35M. The right linear motion portion 50R is connected to the rib 35RM.

[0043] As shown in Figure 4, the lower bend frame 36 extends in the left-right direction and is supported by a plurality of ribs 35. A bending die 31 for normal bending is attached to a front end 36f of the lower bend frame 36. A support portion 36a is provided on the lower surface of the lower bend frame 36 to rotatably support a connecting beam 42 (see Figure 2) of the vertical movement mechanism 40.

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

[0045] Fig. 5 is a diagram illustrating 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 portion 50M is connected and the rib 35LM to which the left linear motion portion 50L is connected. The two notches 37n are located on the left and right sides of the rib 35LR to which the left and central linear motion portions 50M, 50L are not connected.

[0047] Two notches 37n are provided between the rib 35RM to which the right linear motion portion 50R is connected and the rib 35M to which the central linear motion portion 50M is connected. The two notches 37n are located on the left and right sides of the rib 35RL to which the central and right linear motion portions 50M, 50R are not connected.

[0048] Each notch 37n has a curved shape that is recessed toward the front. The curved shape of each notch 37n is configured by combining a radius of curvature Ra with a radius of curvature Rb that is smaller than the radius of curvature Ra. The larger radius of curvature Ra is set on the side of the ribs 35LM, 35M, and 35RM to which the linear motion sections 50L, 50M, and 50R are connected, while the smaller radius of curvature Rb is set on the side of the ribs 35LR and 35RL to which the linear motion sections 50L, 50M, and 50R are not connected. For example, consider the notch 37n between the rib 35M to which the central linear motion section 50M is connected and the rib 35RL to its right. In this case, the region of the notch 37n 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 this embodiment, the left, center, and right linear motion units 50L, 50M, and 50R are driven, causing the ribs 35LM, 35M, and 35RM connected to them to move relatively in the front-to-rear direction. At this time, the bend beam 30 bends in the front-to-rear direction depending on the relative positions of the ribs 35LM, 35M, and 35RM in the front-to-rear direction. For example, the ribs 35LM and 35RM in the left and right regions move relatively rearward relative to the central rib 35M, causing the bend beam 30 to bend so that the center becomes convex forward. Alternatively, the rib 35LM in the left region moves relatively rearward relative to the ribs 35M and 35RM in the center and right regions, causing the bend beam 30 to bend so that the left region faces rearward.

[0050] When the bend beam 30 is bent due to the crowning, stress is concentrated on the upper bend frame 37. In particular, high stress occurs between the ribs 35LM, 35M, and 35RM connecting the left, center, and right linear motion sections 50L, 50M, and 50R because the upper bend frame 37 is significantly bent. As described above, two notches 37n are provided between the ribs 35LM and 35M connecting the left and center linear motion sections 50L and 50M, and two notches 37n are provided between the ribs 35M and 35RM connecting the center and right linear motion sections 50M and 50R. These notches 37n allow the upper bend frame 37 to bend in the front-to-rear direction and prevent stress from concentrating between the ribs 35LM, 35M, and 35RM.

[0051] Furthermore, stress is concentrated significantly near the ribs 35LM, 35M, and 35RM to which the left, center, and right linear motion sections 50L, 50M, and 50R are connected in order to bend the bend beam 30. In this regard, a larger radius of curvature Ra is set for each cutout 37n on the side of the ribs 35LM, 35M, and 35RM. This makes it possible to prevent stress from concentrating near the ribs 35LM, 35M, and 35RM.

[0052] While the structure of the rear end 37r of the upper bend frame 37 has been described with reference to Fig. 5, the structure of the rear end 36r of the lower bend frame 36 is similar. That is, as shown in Fig. 4, a plurality of notches 36n are provided in the rear end 36r of the lower bend frame 36. In this embodiment, a total of four notches 36n are also provided in the rear end 36r of the lower bend frame 36 between the ribs 35LM, 35M, and 35RM to which the left, center, and right linear motion portions 50L, 50M, and 50R are connected.

[0053] The connection structure between the bend beam 30 and the left, center, and right linear motion units 50L, 50M, and 50R will be described with reference to Figures 6 and 7. Figure 6 is a cross-sectional view showing the connection structure between the center linear motion unit 50L and the connecting block 38, and Figure 7 is a cross-sectional view showing the connection structure between the right linear motion unit 50R and the connecting 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 of the central linear motion unit 50M. A self-aligning roller bearing 60 supporting the support shaft 39 is provided at the rear end of the connecting block 38. As shown in Fig. 7, the right linear motion unit 50R has a similar connecting structure, and a support shaft 39 extending in the left-right direction is provided at the front end of the yoke 57. A self-aligning roller bearing 60 supporting the support shaft 39 is provided at the rear end of the connecting block 38. The left linear motion unit 50L has a similar connecting structure, and therefore a description thereof will be omitted.

[0055] As shown in Figures 6 and 7, when no crowning is performed, the connecting block 38 is in a reference state along a reference line La extending in the front-to-rear direction. On the other hand, when the bend beam 30 is bent due to crowning, the connecting block 38 also tilts relative to the reference line La. At this time, the self-aligning roller bearing 60 allows the connecting block 38 to tilt. This allows the bend beam 30 to bend appropriately while preventing a large load from being generated at the connecting portion.

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

[0057] 6, in central linear motion section 50M, a collar 61 is provided between self-aligning roller bearing 60 and yoke 57. This collar 61 restricts left-right movement of self-aligning roller bearing 60. At the central position of bend beam 30, restricting left-right movement of connecting block 38 makes it possible to restrict left-right positional deviation of bend beam 30.

[0058] As described above, the bending machine 1 according to this embodiment includes a bend beam 30 that bends the workpiece W sandwiched between the bottom die 15 and the top die 25 along a bend 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 unit (first drive unit) 50M that moves the bend beam 30 in the front-rear direction along a central drive shaft (first drive shaft) AM that extends in the front-rear direction, and a left linear motion unit (second drive unit) 50L that is disposed spaced apart in the left-right direction from the central linear motion unit 50M and moves the bend beam 30 in the front-rear direction along a left drive shaft (second drive shaft) AL that is parallel to the central drive shaft AM. The bend beam 30 includes notches (first notches) 36n, 37n ​​that are provided between the central drive shaft AM and the left drive shaft AL and that are formed to cut out a portion of the bend beam 30.

[0059] The bend beam 30 bends significantly between the left linear motion section 50L and the central linear motion section 50M, generating high stress. The cutouts 36n and 37n provided in the bend beam 30 prevent stress from concentrating on the curved portion of the bend beam 30. In addition, the bend beam 30 is more easily bent, allowing for greater deformation of the bend beam 30. This allows the bend beam 30 to be deformed into an ideal shape, improving the accuracy of the bending process.

[0060] In this embodiment, the longitudinal movement mechanism 50 further includes a right linear movement unit (third drive unit) 50R that is disposed opposite the left linear movement unit 50L across the central linear movement unit 50M and that moves the bend beam 30 in the longitudinal direction along a right drive shaft (third drive shaft) AR that is parallel to the central drive shaft AM. The bend beam 30 further includes notches (second notches) 36n, 37n ​​that are provided between the central drive shaft AM and the right drive shaft AR and that are formed to cut out portions of the bend beam 30.

[0061] According to this configuration, the left, center, and right linear motion units 50L, 50M, and 50R are connected to the bend beam 30. By moving the bend beam 30 in the forward and backward directions on the three drive shafts AL, AM, and AR, the bend beam 30 can be deformed into any shape.

[0062] Furthermore, the bend beam 30 also bends significantly between the central linear motion section 50M and the right linear motion section 50R, generating high stress. The cutouts 36n, 37n ​​provided in the bend beam 30 prevent stress from concentrating on the curved portion of the bend beam 30. In addition, the bend beam 30 is more easily bent, allowing the bend beam 30 to be deformed significantly. This allows the bend beam 30 to be deformed into an ideal shape, improving the accuracy of the bending process.

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

[0064] One possible mechanism for moving the bend beam 30 in the front-to-rear direction is to use an eccentric shaft that rotates around a rotation axis extending in the left-to-right direction. However, in a configuration using an eccentric shaft, the eccentric shaft has a movement component not only in the front-to-rear direction but also in the up-and-down direction. This can cause twisting in the up-and-down direction in the bend beam 30, which can reduce the accuracy of the bending process.

[0065] According to this embodiment, the bend beam 30 is moved in the front-to-rear direction only by linear motion along the left, center, and right third drive shafts AL, AM, and AR. This prevents the bend beam 30 from twisting in the up-and-down direction, as occurs when an eccentric shaft is used, thereby improving the accuracy of the bending process.

[0066] Furthermore, in a configuration using an eccentric shaft, the maximum amount of movement of the bend beam 30 in the forward / backward direction is equal to the eccentricity of the eccentric shaft. In this embodiment, a linear motion mechanism is used, ensuring a large amount of movement of the bend beam 30 in the forward / backward direction. This allows for large deformation of the bend beam 30. However, a linear motion mechanism requires that the bend beam 30 be easily bent and that stress concentration at the curved portion of the bend beam 30 be suppressed. In this embodiment, while employing a linear motion mechanism, the provision of the notches 36n and 37n in the bend beam 30 as described above provides the bend beam 30 with flexibility and suppresses stress concentration at the curved portion. In this way, by using a linear motion mechanism to significantly deform the bend beam 30, the objective of deforming the bend beam 30 into an ideal shape is achieved.

[0067] In this embodiment, a ball screw mechanism is used as an example of a linear motion mechanism, but the invention is not limited to this. A wide range of linear motion actuators can be used for the left, center, and right drive shafts AL, AM, and AR.

[0068] In this embodiment, the bend beam 30 includes a lower bend frame 36 extending in the left-right direction and having a bending die 31 for forward bending that bends the workpiece W upward mounted thereon, and an upper bend frame extending in the left-right direction and having a bending die 32 for reverse bending that bends the workpiece W downward mounted thereon. The cutouts 36n and 37n are provided in the lower and upper bend frames 36 and 37, respectively.

[0069] With this configuration, the lower and upper bend frames 36, 37, which are rigid bodies extending in the left-right direction, are provided with the notches 36n, 37n. This prevents stress from concentrating on the curved portions of the lower and upper bend frames 36, 37. In addition, the lower and upper bend frames 36, 37 are more flexible, allowing the lower and upper bend frames 36, 37 to deform significantly. This allows the bend beam 30 to be deformed into an ideal shape, improving the accuracy of the bending process.

[0070] In this embodiment, the bend beam 30 further includes a plurality of ribs 35 spaced apart in the left-right direction to reinforce the lower and upper bend frames 36, 37. The left, center, and right linear motion sections 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 and connected to the central linear motion portion 50M, and a rib (second rib) 35LM disposed in the left region of the bend beam 30 and connected to the left linear motion portion 50L. The plurality of ribs 35 also include a rib (third rib) 35RM disposed in the right region of the bend beam 30 and connected to the right linear motion portion. The plurality of ribs 35 further 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 notches 36n and 37n are provided between the rib 35M and the rib 35LR and between the rib 35LR and the rib 35LM, respectively. The notches 36n, 37n ​​are provided between the ribs 35M and 35RL, and between the ribs 35RL and 35RM, respectively.

[0072] The lower and upper bend frames 36, 37 bend significantly between the ribs 35, generating high stress. The cutouts 36n, 37n ​​provided in the lower and upper bend frames 36, 37 prevent stress from concentrating on the curved portions of the lower and upper bend frames 36, 37. In addition, the lower and upper bend frames 36, 37 are more likely to bend, allowing the lower and upper bend frames 36, 37 to deform significantly. This allows the bend beam 30 to be deformed into an ideal shape, improving the accuracy of the bending process.

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

[0074] In the vicinity of the ribs 35LM, 35M, and 35RM that connect the linear motion portions 50L, 50M, and 50R, a load is applied from the linear motion portions 50L, 50M, and 50R during crowning, resulting in significant stress concentration. In this regard, a large radius of curvature Ra is set on each of the cutouts 36n and 37n on the side of the ribs 35LM, 35M, and 35RM. This makes it possible to prevent stress from concentrating in the vicinity of the ribs 35LM, 35M, and 35RM.

[0075] In the above description, the shape of the cutout 37n shown in Figure 5 is exemplified. However, the shape of the cutout 37n is merely an example, and the present embodiment is not limited to this. The rear end 37r of the upper bend frame 37 may be provided with cutouts 37n1 to 37n7 shaped as shown in Figure 8. Figure 8 is a diagram showing the shapes of the cutouts 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 semicircular shape with a constant radius of curvature and a center of curvature located at the rear end 37r. As shown in FIG. 8( b), the notch 37n2 has a semi-elliptical shape obtained by dividing an ellipse in a direction perpendicular to the longitudinal direction. As shown in FIG. 8( c), the notch 37n3 has a semi-elliptical shape obtained by dividing an ellipse along the longitudinal direction. As shown in FIG. 8( d), the notch 37n4 has a shape that combines a circular portion and a rectangular portion. As shown in FIG. 8( e), the notch 37n5 has an arc shape with a constant radius of curvature and a center of curvature located outside the rear end 37r. As shown in FIG. 8( f), the notch 37n6 has a trapezoidal shape consisting of a reference side parallel to the rear end 37r and a pair of symmetrical inclined sides connected to the reference side. As shown in FIG. 8(g), the notch 37n7 has a shape that combines semicircles aligned on the left and right and a rectangular shape located at the boundary between the semicircles.

[0077] The cutouts 37n1 to 37n7 shown in these modified examples can also prevent stress from concentrating on the curved portion of the bend beam 30. In addition, the bend beam 30 becomes more flexible, allowing for greater deformation of the bend beam 30. This allows the bend beam 30 to be deformed into an ideal shape, improving the accuracy of the bending process.

[0078] Although a modified example of the notch 37n of the upper bend frame 37 has been described with reference to FIG. 8, this modified example can also be applied to the notch 36n of the lower bend frame 36.

[0079] Although the present embodiment has been described above, the description and drawings forming a part of this embodiment should not be understood as limiting this embodiment. From this embodiment, various alternative embodiments, examples and operation techniques will become apparent to those skilled in the art.

[0080] The disclosure of this application is related to the subject matter described in Japanese Patent Application No. 2023-204800, filed with the Japan Patent Office on December 4, 2023, the entire disclosure of which is incorporated herein by reference.

Claims

1. A bending machine comprising: a bend beam which bends a workpiece clamped between a bottom die and a top die along a bend line extending in the left-right direction; and a crowning mechanism which deforms the bend beam in the front-to-rear direction, wherein the crowning mechanism has: a first drive unit which moves the bend beam in the front-to-rear direction along a first drive shaft which extends in the front-to-rear direction; and a second drive unit which is arranged spaced apart in the left-to-right direction from the first drive unit and moves the bend beam in the front-to-rear direction along a second drive shaft which is parallel to the first drive shaft, and wherein the bend beam has a first cutout portion which is provided between the first drive shaft and the second drive shaft and which is formed so as to cut out a portion of the bend beam.

2. A bending machine as described in claim 1, wherein the crowning mechanism further has a third drive unit arranged at a position facing the second drive unit across the first drive unit and moving the bend beam in the forward and backward directions along a third drive shaft parallel to the first drive shaft, and the bend beam further has a second cutout portion provided between the first drive shaft and the third drive shaft and formed so as to cut out a portion of the bend beam.

3. The bending machine according to claim 2, wherein the first drive unit, the second drive unit and the third drive unit move the bend beam in the front-to-rear direction by a linear motion mechanism which moves linearly along the first drive shaft, the second drive shaft and the third drive shaft, and the crowning mechanism deforms the bend beam in the front-to-rear direction by the first drive unit, the second drive unit and the third drive unit each being driven independently.

4. A bending machine as described in claim 3, wherein the bend beam comprises a lower bend frame extending in the left-right direction and on which a bending die for forward bending that bends the workpiece in an upward direction is attached, and an upper bend frame extending in the left-right direction and on which a bending die for reverse bending that bends the workpiece in a downward direction is attached, and the first and second cutout portions are provided in the lower bend frame and the upper bend frame, respectively.

5. The bending machine according to claim 4, wherein the bend beam further comprises a plurality of ribs spaced apart in the left-right direction and reinforcing the lower bend frame and the upper bend frame, and the first drive unit, the second drive unit and the third drive unit are connected to three ribs selected from the plurality of ribs.

6. A bending machine as claimed in claim 5, wherein the plurality of ribs include a first rib arranged at the centre of the bend beam and connected to the first drive unit, a second rib arranged in a left region of the bend beam and connected to the second drive unit, a third rib arranged in a right region of the bend beam and connected to the third drive unit, a fourth rib arranged between the first rib and the second rib, and a fifth rib arranged between the first rib and the third rib, wherein the first cutouts are provided between the first rib and the fourth rib and between the fourth rib and the second rib, respectively, and the second cutouts are provided between the first rib and the fifth rib and between the fifth rib and the third rib, respectively.

7. A bending machine as described in claim 6, wherein the curved shapes of the first cutout portion and the second cutout portion 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 a rib side to which each driving unit is connected, and the second radius of curvature is set on a rib side to which each driving unit is not connected.

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