Bending machine, and table drive unit for the same

Abstract

To suppress vibration caused on a rotary driving unit from being transmitted to a body frame.SOLUTION: A press brake 1 as a bending machine includes: a rotary drive unit rotationally driving an output shaft; a ball screw mechanism 55 moving an upper table 7 in a vertical direction by converting the rotational motion of the output shaft into a linear motion along a vertical direction; a connection base 65 structurally connecting the rotary drive unit and the ball screw mechanism 55; a rubber sheet 75 disposed between the connection base 65 and the rotary drive unit to damp vibration; a fastening unit 70 mounting the rotary drive unit on the connection base 65 while required clearance is maintained; and a rotation regulation unit 80 regulating the rotation of the rotary drive unit.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a bending machine and a table drive device for the bending machine. [Background technology]

[0002] A press brake is known as a bending machine that performs bending processing on a workpiece. The press brake performs bending processing on the workpiece by moving a movable table, on which a mold such as a punch is attached, relative to a fixed table, on which a mold such as a die is attached.

[0003] Patent Document 1 discloses a table drive device that uses a rotary drive unit to rotate a ball screw mechanism to move a movable table up and down. The table drive device is attached to a main body frame. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5531878 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in such a drive system, vibrations generated in the rotary drive unit may be transmitted to the main body frame, which not only vibrates the entire machine but also produces abnormal noise. [Means for solving the problem]

[0006] A bending machine of one embodiment of the present invention comprises a movable table supported on a main frame so as to be movable in the vertical direction, a rotational drive unit that rotates an output shaft, a conversion unit attached to the main frame and moving the movable table in the vertical direction by converting the rotational motion of the output shaft into linear motion along the vertical direction, a connecting base that structurally connects the rotational drive unit and the conversion unit, a damping member disposed between the connecting base and the rotational drive unit for damping vibrations, a fastening unit that attaches the rotational drive unit to the connecting base while maintaining the clearance required for vibration damping by the damping member, and a rotation regulating unit attached to the connecting base for regulating the rotation of the rotational drive unit.

[0007] According to one aspect of the present invention, a damping member is provided between the connecting base and the rotary drive unit. The presence of this damping member can suppress the transmission of vibrations generated in the rotary drive unit to the main body frame via the conversion unit. This can suppress the entire machine from vibrating and the generation of abnormal noise.

[0008] At this time, since the fastening unit maintains the necessary clearance between the connecting base and the rotation drive unit, the damping member can adequately damp the vibrations generated in the rotation drive unit without being hindered in its function. In addition, since the rotation restricting unit is present, the movement of the rotation drive unit in the rotational direction can be restricted. Effect of the Invention

[0009] According to one aspect of the present invention, the transmission of vibrations generated in the rotary drive unit can be suppressed, and further, the rotational movement generated in the rotary drive unit can also be suppressed. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a front view showing the overall configuration of a press brake and a table driving device. [Diagram 2]FIG. 2 is a perspective view showing the table driving device of the press brake according to the first embodiment. [Diagram 3] FIG. 3 is an exploded perspective view showing the table driving device of the press brake according to the first embodiment. [Figure 4] FIG. 4 is a top view showing the table driving device of the press brake according to the first embodiment. [Diagram 5] FIG. 5 is a diagram showing the function of the rotation restriction unit according to the first embodiment. [Figure 6] FIG. 6 is a perspective view showing a table driving device of a press brake according to the second embodiment. [Figure 7] FIG. 7 is a top view showing a table driving device of a press brake according to the second embodiment. [Figure 8] FIG. 8 is an exploded perspective view showing a table driving device of a press brake according to the third embodiment. [Figure 9] FIG. 9 is a front view showing the overall configuration of a table driving device according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, with reference to the drawings, a bending machine according to this embodiment will be described using a press brake as an example.

[0012] 1 is a front view showing the overall configuration of a press brake and a table drive device. In this specification, the left-right direction, the front-rear direction, and the up-down direction are used as definitions of directions. 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. These directions are merely used for convenience in explaining the press brake according to this embodiment.

[0013] The press brake 1 of this embodiment comprises an upper table 7 supported on the front side of the side plate 2 so as to be movable in the vertical direction, a rotational drive unit that rotates and drives the output shaft, a ball screw mechanism 55 that is attached to the side plate 2 and moves the upper table 7 in the vertical direction by converting the rotational motion of the output shaft into linear motion along the vertical direction, a connecting base 65 that structurally connects the rotational drive unit and the ball screw mechanism 55, a rubber sheet 75 that is arranged between the connecting base 65 and the rotational drive unit and damps vibrations, a fastening unit 70 that attaches the rotational drive unit to the connecting base 65 while maintaining the clearance required for vibration damping by the rubber sheet 75, and a rotation restricting unit 80 that is attached to the connecting base 65 and restricts the rotation of the rotational drive unit.

[0014] The press brake 1 will be described in detail below. The press brake 1 performs bending processing on a plate-shaped workpiece such as a metal plate by cooperation of an upper tool P such as a punch and a lower tool D such as a die. The press brake 1 includes left and right side plates 2, a lower table 5 which is a fixed table, an upper table 7 which is a movable table, left and right table driving devices 20, and a control device 100.

[0015] The left and right side plates 2 form part of a main body frame. The left and right side plates 2 are disposed opposite each other and spaced apart in the left-right direction.

[0016] The lower table 5 extends in the left-right direction and is supported by the front lower parts of the left and right side plates 2. A lower die holder 6 for detachably holding a lower die D is provided above the lower table 5 along the left-right direction.

[0017] The upper table 7 extends in the left-right direction and is supported on the front upper parts of the left and right side plates 2 so as to face the lower table 5. The upper table 7 is configured to be movable in the up-down direction relative to the left and right side plates 2. An upper die holder 8 that detachably holds an upper die P is provided below the upper table 7 along the left-right direction.

[0018] The left and right table driving devices 20 are respectively fixed to the upper parts of the left and right side plates 2. Each table driving device 20 moves the upper table 7 in the vertical direction. The table driving device 20 is mainly composed of a rotation driving unit and a ball screw mechanism 55.

[0019] The rotary drive unit is composed of an electric motor 25 and a reducer 30, which are integrally connected. The electric motor 25 is, for example, a servo motor, and is provided with an electric motor shaft that rotates around an axis. The reducer 30 reduces the rotation of the electric motor shaft at a predetermined reduction ratio and outputs the reduced rotation. The output shaft of the reducer 30 is connected to a ball screw mechanism 55. The electric motor 25 and the reducer 30 are coaxially arranged such that the electric motor shaft and the output shaft are aligned in a vertical direction. The output shaft of the reducer 30 corresponds to the output shaft of the rotary drive unit.

[0020] The ball screw mechanism 55 is a conversion unit that converts the rotational motion of the output shaft of the reducer 30 into linear motion, thereby moving the upper table 7 in the vertical direction. In this embodiment, the rotation shaft (output shaft) of the rotary drive unit and the rotation shaft (ball screw nut 56) of the ball screw mechanism 55 are coaxially arranged.

[0021] The ball screw mechanism 55 includes a ball screw nut 56 and a ball screw shaft 57. The ball screw nut 56 is supported inside a housing of the ball screw mechanism 55 via a bearing portion. The ball screw nut 56 is connected to the output shaft of the reducer 30, and rotates in response to the rotation of the output shaft. The ball screw shaft 57 is screwed into the ball screw nut 56, and moves up and down as the ball screw nut 56 rotates forward and backward.

[0022] A connection block 60 is connected to the lower end of the ball screw mechanism 55, specifically the lower end of the ball screw shaft 57. A hanging bolt 61 hanging down in the vertical direction is attached to the lower end of the connection block 60, and the hanging bolt 61 supports a support shaft 62 that penetrates the upper table 7 in the front-rear direction. The ball screw shaft 57 is connected to the upper table 7 via the connection block 60, the hanging bolt 61, and the support shaft 62.

[0023] A control device 100 such as an NC (Numerical Control) device that controls the operation of the press brake 1 is supported via a connection arm on the left side plate 2. The control device 100 controls the electric motor 25, the reducer 30, and the like.

[0024] As one of the features of this embodiment, the table drive device 20 includes a connection structure for connecting the rotation drive unit (specifically, the reducer 30) and the ball screw mechanism 55. Hereinafter, the connection structure will be described with reference to Fig. 2 to Fig. 4. As shown in Fig. 2, this connection structure is made up of a connection base 65, a fastening unit 70, a rubber sheet 75, and a rotation restriction unit 80.

[0025] 3, the connecting base 65 is a member that structurally connects the reducer 30 and the ball screw mechanism 55. The connecting base 65 is connected to the upper end side of the ball screw mechanism 55 via a fastening member such as a bolt. The connecting base 65 may be configured as a member independent of the ball screw mechanism 55, or may be configured as a part of the outer housing of the ball screw mechanism 55.

[0026] The fastening unit 70 attaches the reducer 30 to the connecting base 65. The reducer 30 has a flange portion 30a protruding outward at its lower end. As shown in FIG. 4, the flange portion 30a is formed in a quadrangular shape when viewed from above. The fastening units 70 are disposed at the four corner portions 30a1 of the flange portion 30a. As shown in FIG. 3, each corner portion 30a1 has a through hole 30b penetrating in the up-down direction.

[0027] The fastening unit 70 is composed of a stripper bolt 71 and a coil spring 72. The stripper bolt 71 has a cylindrical portion below the head, and a screw shaft is formed at the tip of the cylindrical portion. The stripper bolt 71 is screwed into the connecting base 65 via a through hole 30b provided in the corner portion 30a1.

[0028] The coil spring 72 is attached around the cylindrical portion of the stripper bolt 71. The coil spring 72 is a compression coil spring. The coil spring 72 is disposed between the head of the stripper bolt 71 and the upper surface of the flange portion 30a, and presses the flange portion 30a toward the connecting base 65.

[0029] The rubber sheet 75 is disposed between the flange portion 30a of the reducer 30 and the upper surface of the connecting base 65. The rubber sheet 75 is a rubber sheet having a predetermined thickness and elasticity, and functions as a damping member that damps vibrations generated in the rotation drive unit including the reducer 30. Note that, in this embodiment, the rubber sheet 75 is exemplified as the damping member, but the damping member is not limited to the rubber sheet 75 as long as it has a function of damping vibrations.

[0030] As described above, the reducer 30 is attached to the connecting base 65 by the stripper bolt 71 and the coil spring 72. The fastening force of the fastening unit 70 is obtained by the repulsive force of the coil spring 72 according to the tightening amount of the stripper bolt 71. Therefore, the fastening force of the fastening unit 70 can be adjusted by adjusting the tightening amount of the stripper bolt 71. This makes it possible to attach the reducer 30 to the connecting base 65 while maintaining a clearance between the connecting base 65 and the reducer 30 that is necessary for the damping effect of the rubber sheet 75.

[0031] The rotation restricting unit 80 is attached to the connecting base 65. The rotation restricting unit 80 serves to restrict the rotation of the reducer 30. As shown in FIG. 4, the rotation restricting unit 80 is provided on each of the four side surfaces 30a2 of the flange portion 30a. Each rotation restricting unit 80 is composed of a pressing plate 81, a pair of pressing bolts 82, and a fixing frame 85.

[0032] The pressing plate 81 is a flat member, and is in contact with the side surface 30a2 of the flange portion 30a. A pair of positioning pins 81a are provided on the pressing plate 81. The pair of positioning pins 81a can be inserted into through holes formed in the fixed frame 85 to perform alignment with respect to the fixed frame 85.

[0033] The pair of pressing bolts 82 are disposed between the pressing plate 81 and the fixed frame 85. The tip side of the screw shaft of the pressing bolt 82 is inserted into a through hole formed in the fixed frame 85, and the head of the pressing bolt 82 is located on the pressing plate 81 side. A pair of nuts 83 are attached to the screw shaft of the pressing bolt 82. Of the pair of nuts 83, the nut 83 located on the tip side of the screw shaft has the function of pushing the pressing bolt 82 toward the pressing plate 81. On the other hand, the nut 83 located on the head side has the function of restricting the rotation of the nut 83 located on the tip side of the screw shaft.

[0034] When the pair of nuts 83 is rotated and moved toward the tip end of the screw shaft of the pressing bolt 82, the pair of nuts 83 abuts against the fixed frame 85. When the pair of nuts 83 is further rotated, the pressing bolt 82 is pushed toward the pressing plate 81, and the head of the pressing bolt 82 is pressed against the pressing plate 81. The pressing plate 81 receives a pressing force from the pressing bolt 82 and is pressed against the side surface 30a2 of the flange portion 30a.

[0035] The pair of pressing bolts 82 are disposed at positions spaced a certain distance apart from the center of the pressing plate 81, and are disposed near both ends of the pressing plate 81. The pressing plate 81 is pressed at two points by the pair of pressing bolts 82, and is pressed against the side surface 30a2 of the flange portion 30a.

[0036] The fixed frame 85 is fixed to the connecting base 65 using fastening members such as fixing bolts 86a. The fixed frame 85 is located outward of the pressing plate 81, and serves to hold the pair of pressing bolts 82. Note that the fixed frame 85 is not limited to being directly fixed to the connecting base 65, and may be indirectly fixed to the fixed frame 85 by being fixed to another fixed frame 85 fixed to the connecting base 65.

[0037] In the press brake 1 configured as above, when processing the workpiece, the workpiece is positioned above the lower die D. The control device 100 controls the rotation drive unit to rotate the output shaft of the rotation drive unit in one direction (hereinafter referred to as the "normal rotation direction"). When the ball screw nut 56 rotates in the normal rotation direction in accordance with the rotation of the output shaft of the rotation drive unit, the ball screw shaft 57 moves downward, and the upper table 7 also moves downward accordingly.

[0038] When the upper table 7 reaches a predetermined stroke position, the control device 100 stops the operation of the rotary drive unit and stops the movement of the upper table 7. At this time, the workpiece is sandwiched between the upper die P and the lower die D and bent to the desired angle.

[0039] The control device 100 controls the rotary drive unit to rotate the output shaft of the rotary drive unit in the other direction (hereinafter referred to as the "reverse direction"). When the ball screw nut 56 rotates in the reverse direction in accordance with the rotation of the output shaft of the rotary drive unit, the ball screw shaft 57 moves upward, and the upper table 7 also rises accordingly.

[0040] When the upper table 7 reaches a predetermined upper limit position, the control device 100 stops the operation of the rotary drive unit, and stops the movement of the upper table 7. Then, when a new bending process is to be performed on the workpiece, the above-mentioned steps are repeated.

[0041] According to the connection structure of the table drive device 20, a rubber sheet 75 is provided between the connection base 65 and the reducer 30. The presence of this rubber sheet 75 can suppress the vibration generated in the rotation drive unit from being transmitted to the side plate 2 via the ball screw mechanism 55. This can suppress the entire machine from vibrating and the generation of abnormal noise.

[0042] Incidentally, since it is necessary to obtain a sufficient damping function of the rubber sheet 75, the fastening unit 70 does not firmly attach the reducer 30 to the connecting base 65, but rather attaches it with some slack. This makes it possible to maintain a necessary clearance between the connecting base 65 and the reducer 30, thereby obtaining a sufficient damping function of the rubber sheet 75. As a result, the rubber sheet 75 can adequately damp vibrations generated in the rotation drive unit.

[0043] On the other hand, in the case of such a fastening method, the degree of freedom of the reducer 30 with respect to the connecting base 65 increases, so there is a risk that the reducer 30 may move in the opposite direction to the rotational direction of the output shaft due to the effect of the reaction force from the ball screw mechanism 55. In this regard, according to the present embodiment, the existence of the rotation restriction unit 80 makes it possible to restrict the movement of the reducer 30 in the rotational direction.

[0044] Therefore, according to the press brake 1 and table drive device 20 of this embodiment, the transmission of vibrations generated in the rotary drive unit can be appropriately suppressed, and further, the rotational movement generated in the rotary drive unit can also be effectively suppressed.

[0045] In this embodiment, an outwardly projecting flange portion 30a is provided at an end of the reducer 30. The fastening unit 70 includes a stripper bolt 71 screwed into the connecting base 65 via a through hole 30b provided in the flange portion 30a, and a coil spring 72 attached around the stripper bolt 71 to press the flange portion 30a toward the connecting base 65.

[0046] According to this configuration, the fastening force of the fastening unit 70 can be adjusted by adjusting the tightening amount of the stripper bolt 71. As a result, while the reducer 30 is attached to the connecting base 65, the clearance required for the damping effect of the rubber sheet 75 can be appropriately maintained.

[0047] In this embodiment, the flange portion 30a has a rectangular shape, and the rotation restriction units 80 are provided on each of the four side surfaces 30a2 of the flange portion 30a. Each of the rotation restriction units 80 includes a pressing plate 81 that abuts against the side surface 30a2 that forms the outer periphery of the flange portion 30a, a fixed frame 85 that is fixed to the connecting base 65 and is positioned outwardly of the pressing plate 81, and a pair of pressing bolts 82 that are disposed between the pressing plate 81 and the fixed frame 85 and press the pressing plate 81 against the side surface 30a2 of the flange portion 30a.

[0048] According to this configuration, the pair of pressing bolts 82 can press the pressing plate 81 against the side surface 30a2 of the flange portion 30a. This allows each side surface 30a2 of the flange portion 30a to be stably fixed. In addition, since the pair of pressing bolts 82 contact the pressing plate 81 at points, vibrations transmitted from the pressing bolts 82 to the fixed frame 85 and ultimately to the ball screw mechanism 55 can be suppressed.

[0049] In this embodiment, the pair of pressure bolts 82 are disposed at positions spaced a certain distance apart from each other with the center of the pressure plate 81 as the boundary.

[0050] As shown in FIG. 5, the rotation direction of the output shaft of the reducer 30 is reversed when the upper table 7 is raised and when it is lowered. By disposing the pressing bolts 82 at two locations, one pressing bolt 82 can regulate the rotation of the reducer 30 when the upper table 7 is raised (arrow P1), and the other pressing bolt 82 can regulate the rotation of the reducer 30 when the upper table 7 is lowered (arrow P2). Therefore, the pair of pressing bolts 82 can share the role of regulating the rotation of the reducer 30 when the upper table 7 is raised and the role of regulating the rotation of the reducer 30 when the upper table 7 is lowered. This makes it possible to effectively regulate the rotation in both directions of the reducer 30 in the press brake 1 that performs the unique movement of raising and lowering the upper table 7.

[0051] Since the rotation restricting units 80 are configured to press the side surfaces 30a2 of the flange portion 30a of the reducer 30, they are provided on each of the four side surfaces 30a2 of the flange portion 30a. However, it is sufficient that the rotation restricting units 80 are provided on at least one of the four side surfaces 30a2 of the flange portion 30a. However, it is preferable to provide the rotation restricting units 80 on the four side surfaces 30a2 of the flange portion 30a, since the rotational force of the reducer 30 can be distributed and received by the four rotation restricting units 80.

[0052] Second Embodiment A press brake according to the second embodiment will be described below. The press brake according to the second embodiment differs from the first embodiment in the structure of the rotation restriction unit 80 in the table drive device 20. Below, a description of the contents common to the first embodiment will be omitted, and the description will focus on the differences.

[0053] Fig. 6 is a perspective view showing the table drive device of the press brake according to the second embodiment. Fig. 7 is a top view showing the table drive device of the press brake according to the second embodiment.

[0054] In this embodiment, the rotation restriction units 80 are provided at a pair of diagonally opposite corner portions 30a1 of the flange portion 30a. Each of the rotation restriction units 80 includes a fixing bracket 87 and a pair of fixing bolts 88.

[0055] The fixed bracket 87 has an L-shape that conforms to the shape of the corner portion 30a1. The fixed bracket 87 is disposed on the connecting base 65 and positioned so as to come into contact with the periphery of the corner portion 30a1.

[0056] The pair of fixing bolts 88 are screwed into the connecting base 65 via through holes provided at both ends of the fixing bracket 87. The fixing bracket 87 is fixed to the connecting base 65 by the fastening force of the pair of fixing bolts 88.

[0057] The rotation restriction unit 80 having such a structure includes an L-shaped fixed bracket 87 along the corner portion 30a1 of the flange portion 30a, and a fixing bolt 88 for fixing the fixed bracket 87 to the connecting base 65. The L-shaped fixed bracket 87 surrounds the periphery of the corner portion 30a1, so that the two side surfaces 30a2 connected to the corner portion 30a1 can be held down by the fixed bracket 87. As a result, one end of the fixed bracket 87 can restrict the rotation of the reducer 30 when the upper table 7 is raised (arrow P1), and the other end of the fixed bracket 87 can restrict the rotation of the reducer 30 when the upper table 7 is lowered (arrow P2). Therefore, the L-shaped fixed bracket 87 can restrict the rotation of the reducer 30 when the upper table 7 is raised and when the upper table 7 is lowered. As a result, in the press brake 1 that performs the unique movement of raising and lowering the upper table 7, the rotation in both directions that occurs in the reducer 30 can be effectively restricted.

[0058] Since the rotation restricting units 80 are configured to press the corner portions 30a1 of the flange portion 30a, they are provided at each of a pair of diagonally opposite corner portions 30a1. However, it is sufficient that the rotation restricting units 80 are provided at at least one of the four corner portions 30a1 of the flange portion 30a. However, by disposing the rotation restricting units 80 at the pair of diagonally opposite corner portions 30a1, the rotational force of the reducer 30 can be distributed and received by the two rotation restricting units 80, which is preferable.

[0059] (Third embodiment) A press brake according to the third embodiment will be described below. The press brake according to the third embodiment differs from the first embodiment in the structure of the rotation restriction unit 80 in the table drive device. Below, a description of the contents in common with the first embodiment will be omitted, and the description will focus on the differences.

[0060] FIG. 8 is an exploded perspective view showing a table driving device of a press brake according to the third embodiment.

[0061] In this embodiment, the stripper bolt 71 of the fastening unit 70 not only functions to attach the reducer 30 to the connecting base 65, but also functions as a rotation restricting unit 80 that restricts the rotation of the rotary drive unit. Specifically, the rotation restricting units 80 are provided at the four corner portions 30a1 of the flange portion 30a. The rotation restricting units 80 restrict the rotation of the reducer 30 by fitting the stripper bolt 71 into the through hole 30b of the flange portion 30a. That is, the outer diameter of the cylindrical portion of the stripper bolt 71 corresponds to the inner diameter of the through hole 30b so that the cylindrical portion of the stripper bolt 71 and the through hole 30b are tightly fitted together.

[0062] According to this structure, the cylindrical portion of the stripper bolt 71 and the through hole 30b of the flange portion 30a are tightly fitted together, so that the movement of the reducer 30 is restricted, and the movement of the reducer 30 in the rotational direction can be restricted. Also, since the entire circumference of the stripper bolt 71 is covered by the through hole 30b, the stripper bolt 71 can restrict the rotation of the reducer 30 when the upper table 7 is raised, and can also restrict the rotation of the reducer 30 when the upper table 7 is lowered. This makes it possible to effectively restrict the rotation in both directions of the reducer 30 in the press brake 1, which performs the unique movement of raising and lowering the upper table 7.

[0063] Since the rotation restriction units 80 are configured to press the four corner portions 30a1 of the flange portion 30a, it is preferable that the rotation restriction units 80 are provided at each of the four corner portions 30a1. However, it is sufficient that the rotation restriction units 80 are provided at at least two of the four corner portions 30a1 of the flange portion 30a. However, it is preferable to provide the rotation restriction units 80 at the four corner portions 30a1, since each of the rotation restriction units 80 can receive the rotational force of the reducer 30 evenly.

[0064] (Modification) FIG. 9 is a side view showing the overall configuration of a table drive device according to a modified example. In the table drive device 20 shown in the first to third embodiments described above, the rotation shaft (output shaft) of the rotation drive unit consisting of the electric motor 25 and the speed reducer 30 and the rotation shaft (ball screw nut 56) of the ball screw mechanism 55 are arranged coaxially. However, as shown in FIG. 9, the rotation drive unit and the ball screw mechanism 55 may be arranged side by side in the front-rear direction so that the rotation shaft (output shaft 41 of the speed reducer 30) of the rotation drive unit and the rotation shaft (ball screw nut 56) of the ball screw mechanism 55 are parallel to each other. In this case, the ball screw mechanism 55, which is a conversion unit, also includes a required structure such as a timing belt 43. The output shaft 41 of the speed reducer 30 and the ball screw nut 56 of the ball screw mechanism 55 are connected by the timing belt 43, and power is transmitted via this timing belt 43.

[0065] The above-mentioned connection structure can also be applied to the table drive device 20 configured in this way. In this case, the reducer 30 of the rotation drive unit is structurally connected to the conversion unit including the ball screw mechanism 55 by the connection base 65. The fastening unit 70 attaches the reducer 30 to the connection base 65. The rubber sheet 75 is disposed between the reducer 30 and the connection base 65. The rotation restriction unit 80 is attached to the connection base 65 and restricts the rotation of the reducer 30.

[0066] According to such a configuration, the transmission of vibrations generated in the rotary drive unit can be appropriately suppressed, and further, the movement in the rotational direction generated in the rotary drive unit can also be effectively suppressed.

[0067] As described above, the present embodiment has been described, but the description 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 symbols]

[0068] 1. Press brake 2 Side Plates 5 Lower Table 7 Upper table (movable table) 20 Table drive unit 25 Electric motor (rotary drive unit) 30 Reducer (rotary drive unit) 30a Flange part 30a1 Corner section 30a2 side 30b through hole 55 Ball screw mechanism (conversion unit) 56 Ball screw nut 57 Ball screw shaft 65 Consolidated basis 70 Fastening Unit 71 Stripper bolt 75 Rubber sheet (damping material) 80 Rotation control unit 81 Pressing plate 81a Locating pin 82 Press bolt 83 Nut 85 Fixed Frame 86a Fixing bolt 87 Fixing bracket 88 Fixing bolt

Claims

1. a movable table supported on a main body frame so as to be movable in the vertical direction; A rotation drive unit that rotates an output shaft; a conversion unit attached to the main body frame, which converts the rotational motion of the output shaft into linear motion along a vertical direction to move the movable table in the vertical direction; a coupling base that structurally couples the rotary drive unit and the conversion unit; a damping member disposed between the connecting base and the rotary drive unit for damping vibration; a fastening unit that attaches the rotation drive unit to the connection base while maintaining a clearance required for vibration damping by the damping member; a rotation restricting unit attached to the connection base and configured to restrict rotation of the rotation drive unit.

2. The rotary drive unit has an end provided with an outwardly protruding flange portion, The fastening unit includes: a bolt screwed into the connecting base through a through hole provided in the flange portion; 2. The bending machine according to claim 1, further comprising: a coil spring attached around the bolt to press the flange portion toward the connecting base.

3. The rotation restriction unit includes: a flange portion protruding outward is provided at an end of the rotation drive unit, and a pressing plate abuts against a side surface forming an outer periphery of the flange portion; a fixed frame fixed to the connecting base and positioned outside the pressing plate; 2. The bending machine according to claim 1, further comprising: a pair of pressure bolts disposed between the pressure plate and the fixed frame for pressing the pressure plate against the side surfaces of the flange portion.

4. The flange portion is rectangular in shape, 4. The bending machine according to claim 3, wherein the rotation restricting unit is provided on each of four side surfaces of the flange portion.

5. 5. The bending machine according to claim 3, wherein the pair of pressure bolts are disposed at positions spaced a given distance apart from each other with the center of the pressure plate as a boundary.

6. The rotary drive unit has an end portion provided with an outwardly protruding flange portion, the flange portion having a rectangular shape, The rotation restriction unit includes: An L-shaped fixing bracket along a corner portion of the flange portion; 2. The bending machine according to claim 1, further comprising a fastening member for fastening said fixed bracket to said connecting base.

7. 7. The bending machine according to claim 6, wherein the rotation restricting units are provided at a pair of diagonally opposite corners of the flange portion.

8. 3. The bending machine according to claim 2, wherein the rotation restricting unit restricts the rotation of the rotary drive unit by fitting the bolt into the through hole.

9. The flange portion is rectangular in shape, 9. The bending machine according to claim 8, wherein the through holes are provided at four corners of the flange portion.

10. 3. The bending machine according to claim 1, wherein the damping member is an elastic rubber sheet.

11. 3. The bending machine according to claim 1, wherein the output shaft of the rotary drive unit reverses its rotation direction at a timing when the vertical movement of the movable table is switched.

12. A rotation drive unit that rotates an output shaft; a conversion unit that converts the rotational motion of the output shaft into a linear motion along a vertical direction to move a movable table of the bending machine in the vertical direction; a coupling base that structurally couples the rotary drive unit and the conversion unit; a damping member disposed between the connecting base and the rotary drive unit for damping vibration; a fastening unit that attaches the rotation drive unit to the connection base while maintaining a clearance required for vibration damping by the damping member; a rotation restricting unit attached to the connection base and configured to restrict rotation of the rotation drive unit.

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