JP4329095B2 - Bending machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bending apparatus provided with a deflection correcting means.
[0002]
[Prior art]
[0003]
For example, the conventional press brake has the configuration shown in FIG. 9. In the case of the descending type, when the upper table 50 is lowered, the punch P attached to the upper table 50 and the die attached to the lower table 51 are arranged. The workpiece W is bent in cooperation with D.
[0004]
However, during the bending process, the upper table 50 receives a bending load a ′ which is a reaction force from the workpiece W, so that the upper table 50 bends upward in a concave shape as shown in the figure.
[0005]
As a result, the actual bending angle of the workpiece W is different from a target value (for example, 90 °), and the bending angles α, β, and γ along the longitudinal direction of the workpiece W are not uniform as shown in FIG. As a result, the accuracy of processing decreases, and the processing accuracy decreases.
[0006]
[Problems to be solved by the invention]
In order to avoid this, conventionally, as disclosed in, for example, JP-A-5-329546 and 5-329549, a crowning cylinder is provided, and the deflection of the table is corrected by the pressure of the crowning cylinder.
[0007]
However, this crowning cylinder is fixed, so that it cannot sufficiently cope with the correction of the non-target deflection of the table in step bending.
[0008]
Further, Japanese Patent Publication No. 52-5464 can correct a non-target deflection by providing a plurality of crowning cylinders, and Japanese Patent Laid-Open No. 58-320 and Japanese Patent No. 3003515 by providing a plurality of crowning wedges. Since a plurality of cylinders and wedges are provided in this way, the configuration becomes complicated, and it takes time to assemble the whole. In addition, it is difficult to process the wedges with high accuracy, which increases the cost. .
[0009]
Among these, in particular, the deflection correcting means disclosed in Japanese Patent No. 3003515 is provided with a plurality of a pair of wedges composed of an upper wedge 160 (FIG. 2 of the same publication) and a lower wedge 150, and the configuration becomes more complicated. As a result, the time required for assembly is further increased, and it is extremely difficult to accurately process the pair of wedges 160 and 150.
[0010]
Furthermore, in this patent No. 3003515, the movable fulcrum member 137c is moved in the longitudinal direction (FIGS. 2 and 3 of the same publication), and the beam 140 is bent on the inner surface of the horizontal plane, whereby the lower wedge 150 is moved in the front-rear direction. The height of the upper wedge 160 is adjusted.
[0011]
However, in general, such an operation is troublesome. Especially for an inexperienced inexperienced person, such a troublesome operation is performed by predicting the deflection center position and the amount of deflection that change in each bending process. This is an extremely difficult task, and it is clear that there are many errors even if it is carried out.
[0012]
As a result, the deflection correction means of Japanese Patent No. 3003515 is difficult for an unskilled person to handle easily, and accordingly, the overall operation time is also slowed down. Therefore, the deflection of the table is corrected. It is clear that it takes time to machine the workpiece, and the machining efficiency is lowered.
[0013]
An object of the present invention is to provide a deflection correcting means that can be handled easily even by an unskilled person, has a quick operation, has a simple structure, and is easily assembled.
[0014]
[Means for Solving the Problems]
In order to solve the above problems, the present invention, as shown in FIGS.
In a bending apparatus that moves one of the upper table 1 to which the punch P is attached and the lower table 2 to which the die D is attached, and bends the workpiece W by the cooperation of the punch P and the die D.
Within the rectangular gap 3 provided in the table, the correction block 4 is mounted so as to be freely positionable in the longitudinal direction, and is supported by the correction block 4 and presses the gap 3 to correct the deflection of the table. A deflection correction means T constituted by the correction cylinder 5;
Based on the processing conditions, for each bending process, the deflection center position b, which is a bending position based on the machine center MC that maximizes the deflection of the table, and the deflection amount c at the deflection center position b are made zero. Correction information calculation means 24F for calculating correction information consisting of a predetermined pressure d of
Correction block drive control means 24G for operating the correction block 4 for each bending step and positioning the correction block 4 at the calculated deflection center position b;
It is characterized by having a correction cylinder drive control means 24H that operates the correction cylinder 5 for each bending process and applies the calculated predetermined pressure d to the table by the correction cylinder 5. The technical means of processing equipment is taken.
[0015]
According to the configuration of the present invention, the deflection correction means T has a configuration in which the correction cylinder 5 is supported by the correction block 4 that can be positioned within the gap portion 3, so that the configuration is simplified and the assembly is easy. Thus, according to the bending apparatus having such a deflection correction means T, it is only necessary to input the processing conditions (step 101 in FIG. 8), and thereafter, for each bending process based on the input processing conditions, for example, Correction information such as the deflection center position b received by the upper table 1 and ram information such as the stroke amounts s1 and s2 of the upper table 1 are automatically calculated (steps 102 to 103 in FIG. 8). 7) (step 104 in FIG. 8), and after processing is started (step 105 in FIG. 8), this database is searched. Since the deflection correction operation and the bending operation are automatically repeated for each bending process (steps 106 to 114 in FIG. 8), even an unskilled person can easily handle the operation and the operation is quick. Done.
[0016]
Therefore, according to the present invention, it is possible to provide a deflection correction means that can be handled easily even by an unskilled person, has a simple operation, and is easy to assemble. .
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described with reference to the accompanying drawings by embodiments.
FIG. 1 is an overall view showing an embodiment of the present invention.
[0018]
The bending apparatus shown in FIG. 1 is, for example, a descending press brake.
[0019]
This press brake has an intermediate plate on the upper table 113And a die D attached to the lower table 2 via a die holder 14.
[0020]
Nuts 12 are fixed to the rear portions on both sides of the upper table 1. For example, an AC servo motor M installed on the top of each side plate 26 is attached to the nut 12._L, M_RThe ball screw 11 is screwed.
[0021]
With this configuration, the AC servo motor M is passed through the ram drive control means 24E of the NC device 24 described later._L, M_RIs operated, the upper table 1 moves up and down, and a predetermined bending process can be performed on the workpiece W by the punch P and the die D (step 111 in FIG. 8).
[0022]
In this case, the control signals S1 (FIG. 3) and S2 from the ram drive control means 24E are converted into currents by the servo drivers 23 and 26, and the AC servomotor M is activated by the start signals S3 and S4._L, M_RBy operating and rotating, the upper table 1 moves up and down.
[0023]
The position of the upper table 1 is detected by feedback signals S5 and S6 from the position sensors 21 and 22. The feedback signals S5 and S6 are supplied to the ram drive control means 24E as current values and to the servo drivers 23 and 26, respectively. The positioning control of the upper table 1 is performed by inputting each as a speed signal.
[0024]
As shown in the figure, the upper table 1 (FIG. 1) is formed with a rectangular gap portion 3 that constitutes a deflection correction means T, outside the upper portion of the gap portion 3 and before and after the upper table 1. In the part (FIG. 2), a support plate 8 is provided.
[0025]
Each support plate 8 is provided with a linear motion guide 9, and each linear motion guide 9 has a front portion (Y-axis direction) and a rear portion of a correction block (crowning block) 4 to be described later via a slider 7. It is slip-coupled.
[0026]
The correction block 4 includes an electric motor M, which is a self-propelled drive source, at the center in the front-rear direction (Y-axis direction)._NA correction cylinder (crowning cylinder) 5 to be described later is arranged in the vertical direction.
[0027]
The above motor M_NIs a nut rotary AC servo motor, for example. The nut 15 is screwed into the ball screw 10, and the ball screw 10 extends along the longitudinal direction (X-axis direction) in the gap 3. The left and right end portions of the ball screw 10 are fixed to the left and right inner surfaces of the gap portion 3 (FIG. 1).
[0028]
As a result, the AC servo motor M_NIf the nut 15 is operated, the correction block 4 is allowed to self-run in the longitudinal direction (X-axis direction) by rotating the nut 15.
[0029]
The correction cylinder 5 is constituted by, for example, a hydraulic cylinder (FIG. 3), and the piston rod 6 (FIG. 2) faces the lower surface 3B of the gap 3. If the piston 17 is lowered, the piston rod 6 contacts the lower surface 3B and presses it.
[0030]
Further, the AC servo motor M of the correction block 4_NA constant gap δ is formed between the side and the gap 3.
[0031]
Accordingly, after positioning the correction block 4 at a deflection center position b (FIG. 6B) described later, the correction cylinder 5 is operated (FIG. 2) and the lower surface 3B of the gap 3 is pressed by the piston rod 6. The reaction force is transmitted from the lower surface 3B to the correction block 4, and the correction block 4 is displaced upward.
[0032]
When the pressure in the correction cylinder 5 increases, the correction block 4 comes into contact with the upper surface 3A of the gap 3 and the lower surface 8A of the support plate 8, and the gap δ becomes zero.
[0033]
In this case, even if the gap δ becomes zero, the ball constituting the slider 7 of the linear guide 9 is within the elastic limit, and when the pressure of the correction cylinder 5 is lost, the gap δ is originally large. Therefore, the correction block 4 can be moved again in the longitudinal direction (X-axis direction) by the linear motion guide 9 and the slider 7 mechanism.
[0034]
When the pressure of the correction cylinder 5 further increases, the correction block 4 expands the upper surface 3A side and the lower surface 3B side of the gap portion 3 to increase the vertical dimension H of the gap portion 3, thereby The downward convex deflection that offsets the upward concave (FIG. 9) deflection of the table 1 increases.
[0035]
As a result, when the pressure of the correction cylinder 5 reaches a predetermined pressure (crowning pressure) d for making the deflection amount c at the deflection center position b zero (FIG. 6C) (FIG. 6D). The deflection amount c of the upper table 1 becomes 0, and the deflection is corrected.
[0036]
With this configuration, the nut rotary AC servo motor M described above is provided via the correction block drive control means 24G of the NC device 24 described later (FIG. 1)._NIs operated, the correction block 4 can be positioned at the deflection center position b (step 106 in FIG. 8).
[0037]
Then, with the correction block 4 positioned at the deflection center position b, the upper table 1 is lowered via the ram drive control means 24E (FIG. 1) (step 107 in FIG. 8), and the position sensor 21 (FIG. 3). ) And 22, when it is detected that the punch P has contacted the workpiece W (YES in step 108 in FIG. 8), the correction cylinder 5 is controlled via the correction cylinder drive control means 24 </ b> H (described later) (FIG. 1). The piston 17 is lowered (step 109 in FIG. 8), and a predetermined pressure d that makes the deflection amount c zero can be applied to the upper table 1 (YES in step 110 in FIG. 8).
[0038]
In this case, the control signal S7 (FIG. 3) from the correction block drive control means 24G is converted into a current by the servo driver 19, and the AC servo motor M is received by the start signal S8._NWhen the nut 15 of the shaft rotates, the correction block 4 moves in the longitudinal direction (X-axis direction) (FIG. 1) along the ball screw 10 and is positioned at the deflection center position b (FIG. 6B). Can do.
[0039]
Nut rotation type AC servo motor M_NThe rotation angle of the nut 15 in FIG. 3 (in other words, the movement position of the correction block 4) is detected by a feedback signal S9 from the rotary encoder E. The feedback signal S9 is sent to the correction block drive control means 24G. Positioning control of the correction block 4 is performed by inputting the current value to the servo driver 19 as a speed signal.
[0040]
The control signal S10 (FIG. 3) from the correction cylinder drive control means 24H is converted into a current by the servo driver 20, and the spool of the direction switching valve 18 (for example, a 4-port 3-position proportional solenoid valve) is moved by the start signal S11. Ports A and P and ports B and R are connected to each other.
[0041]
As a result, the hydraulic oil flowing out from the hydraulic source 25 passes through the ports P and A, flows into the head side pressure oil chamber 5A of the correction cylinder 5 and lowers the piston 17, and the piston rod 6 is moved into the gap 3 ( 2) Press the lower surface 3B.
[0042]
At this time, the hydraulic oil in the rod-side pressure oil chamber 5B passes through the ports B and R and returns to the oil tank.
[0043]
While the correction cylinder 5 presses the lower surface 3B of the gap 3 (FIG. 2), the detection signal S12 from the pressure sensor 16 attached to the head-side pressure oil chamber 5A (FIG. 3) When the current pressure value is input to the correction cylinder drive control means 24H and coincides with the target value, the pressure has reached a predetermined pressure d for making the deflection amount c (FIG. 6C) zero. And the predetermined pressure d is maintained.
[0044]
That is, when the pressure of the correction cylinder 5 reaches a predetermined pressure d, the correction cylinder drive control means 24H (FIG. 3) is used to return the direction switching valve 18 to the neutral position, thereby The supply of hydraulic oil to the head side pressure oil chamber 5A of the correction cylinder 5 is stopped, and thereby a predetermined pressure d is maintained.
[0045]
Thereafter, as described above, bending is performed (step 111 in FIG. 8). After the bending is completed, the direction switching valve 18 is similarly turned on via the correction cylinder drive control means 24H (FIG. 3). In operation, ports A and R are connected to ports B and P, respectively.
[0046]
As a result, the hydraulic oil flowing out from the hydraulic source 25 passes through the ports P and B and flows into the rod-side pressure oil chamber 5B of the correction cylinder 5 to raise the piston 17 (step 112 in FIG. 8), and the piston rod 6 Is retracted from the lower surface 3B of the gap 3 (FIG. 2), and the deflection correction operation of the upper table 1 ends.
[0047]
At this time, the hydraulic oil in the head-side pressure oil chamber 5A passes through the ports A and R and returns to the oil tank.
[0048]
The press brake NC device 24 having such a configuration (FIG. 1) includes a CPU 24A, an input / output means 24B, a storage means 24C, a ram information calculation means 24D, a ram drive control means 24E, and a correction information calculation means. 24F, correction block drive control means 24G, and correction cylinder drive control means 24H.
[0049]
The CPU 24A controls the entire apparatus shown in FIG. 1, such as the correction information calculation unit 24F and the correction block drive control unit 24G, according to an operation procedure (for example, corresponding to FIG. 8) for carrying out the present invention.
[0050]
The input / output means 24B is composed of, for example, an input unit made up of operation members such as a keyboard and a switch, and an output unit made up of a screen such as a liquid crystal display or a CRT. The result can be confirmed on the screen.
[0051]
In this case, the processing conditions (FIG. 4) include, for example, the following, and using these as parameters, the deflection center position b received by the upper table 1 (FIG. 6B)) and correction information ( 7), the ram information such as the stroke amounts s1, s2 of the upper table 1 is calculated.
[0052]
(1) Work conditions: Work W material, plate thickness, bending length
(2) Bending conditions: Bending angle and bending position of workpiece W
(3) Mold conditions: punch P and die D type, die D V groove width, V groove angle
(4) Machine conditions: Machine rigidity value (deflection constant depending on machine shape)
[0053]
For example, as shown in FIG. 4, when a workpiece W having the shape shown in the figure is to be processed and the flanges F1, F2,... Enter the conditions.
[0054]
The storage means 24C (FIG. 1) stores, for example, the results calculated by the correction information calculation means 24F and the ram information calculation means 24D using the machining conditions as a database (FIG. 7) (step 104 in FIG. 8). ).
[0055]
The ram information calculation means 24D (FIG. 1) calculates ram information consisting of the stroke amounts s1 and s2 of the upper table 1 for each bending process based on the machining conditions (step 103 in FIG. 8).
[0056]
In this case, the ram information calculation means 24D (FIG. 1), before the machining is started (step 105 in FIG. 8), for each bending process, based on the machining conditions input via the input / output means 24B. The ram information composed of the stroke amounts s1 and s2 of the upper table 1 is calculated (step 103 in FIG. 8), and as described above, the calculation result is (FIG. 7), and the ram information of the ram information is determined separately for the bending steps 1, 2,. It is stored in the storage means 24C as a database (step 104 in FIG. 8).
[0057]
The ram drive control means 24E (FIG. 1) moves the upper table 1 by a predetermined stroke amount s1, s2 for each bending process.
[0058]
In this case, the ram drive control means 24E searches the ram information database calculated by the ram information calculation means 24D and stored in the storage means 24C (FIG. 7), and for each bending process, the servo driver 23 (described above) 3), 26 via left and right AC servo motors M_L, M_RAnd the positioning of the upper table 1 are controlled via the position sensors 21 and 22.
[0059]
Thereby, the ram drive control means 24E can move the upper table 1 by the predetermined stroke amounts s1 and s2 for each bending process as described above (step 107 or 113 in FIG. 8).
[0060]
The correction information calculation means 24F (FIG. 1), based on the machining conditions, for each bending step, the deflection center position b received by the table and the predetermined pressure d for making the deflection amount c at the deflection center position b zero. The correction information consisting of
[0061]
That is, the correction information calculation means 24F is received by the upper table 1 for each bending process based on the machining conditions input via the input / output means 24B before machining is started (step 105 in FIG. 8). Correction information including the deflection center position b is calculated (step 102 in FIG. 8), and the calculation result (FIG. 7) is stored in the storage means 24C as a correction information database separately for the bending steps 1, 2,. (Step 104 in FIG. 8).
[0062]
In this case, the correction information calculation unit 24F includes a bending load calculation unit 24F1, a deflection center position calculation unit 24F2, a deflection amount calculation unit 24F3, and a pressure calculation unit 24F4, as shown in FIG.
[0063]
Based on the material of the workpiece W in the machining conditions, the bending load calculation unit 24F1 can perform, for example, a bending load a = f₁According to the formulas (material, plate thickness, bending length, V groove width), the bending load a received by the upper table 1 (FIG. 6A) is calculated.
[0064]
The deflection center position calculation unit 24F2 (FIG. 5) determines, for example, the deflection center position b = f based on the bending position in the processing conditions.₂In accordance with the equation of (bending position), the deflection center position b is calculated with reference to the mechanical center MC at which the deflection of the upper table 1 ((B) in FIG. 6) becomes maximum.
[0065]
The deflection amount calculation unit 24F3 (FIG. 5) includes a mechanical rigidity value among the machining conditions, a bending load a calculated by the bending load calculation unit 24F1, and a deflection center position b calculated by the deflection center position calculation unit 24F2. For example, the deflection amount c = f_ThreeIn accordance with the equation (mechanical rigidity value, bending load, deflection center position), the deflection amount c at the deflection center position b (FIG. 6B) of the upper table 1 (FIG. 6C) is calculated.
[0066]
The pressure calculation unit 24F4 (FIG. 5), for example, based on the deflection amount c calculated by the deflection amount calculation unit 24F3, for example, a predetermined pressure d = f_FourA predetermined pressure (crowning pressure) d for making the deflection amount c (FIG. 6C) of the upper table 1 (FIG. 6D) zero is calculated according to the equation of (deflection amount).
[0067]
As described above, the calculation results by the respective units 24F1 to 24F4 (FIG. 5) are stored in the storage unit 24C as a correction information database (FIG. 7) (step 104 in FIG. 8).
[0068]
Of the correction information (FIG. 7), for example, the deflection center position b is searched by the correction block drive control means 24G (FIG. 1) to position the correction block 4 (FIG. 8). Step 106) Used.
[0069]
In addition, the correction cylinder drive control means 24H (FIG. 1) searches for the predetermined pressure d (FIG. 7), thereby operating the correction cylinder 5 so that the lower surface 3B (FIG. 2) of the gap 3 is moved. This is used when the deflection is corrected by pressing the deflection amount c of the upper table 1 (FIG. 6C) to zero (FIG. 6D) (YES in steps 109 to 110 in FIG. 8).
[0070]
On the other hand, the correction block drive control means 24G (FIG. 1) operates the correction block 4 for each bending process, and positions the correction block 4 at the deflection center position b calculated by the correction information calculation means 24F.
[0071]
In this case, as described above, the correction block drive control unit 24G searches the correction information database stored in the storage unit 24C (FIG. 7) and searches the servo driver 19 (FIG. 3) for each bending process. Through the nut rotation type AC servo motor M built in the correction block 4_NThe correction block 4 is positioned and controlled via the rotary encoder E.
[0072]
Thereby, as described above, the correction block drive control unit 24G can operate the correction block 4 and position the correction block 4 at the deflection center position b for each bending process (step of FIG. 8). 106).
[0073]
Further, the correction cylinder drive control means 24H (FIG. 1) operates the correction cylinder 5 for each bending process, and the correction cylinder 5 gives a predetermined pressure d calculated by the correction information calculation means 24F to the table. Let
[0074]
In this case, as described above, the correction cylinder drive control means 24H searches the correction information database stored in the storage means 24C (FIG. 7) and searches the servo driver 20 (FIG. 3) for each bending process. The directional control valve 18 is activated to drive and control the pressure in the pressure oil chamber 5 </ b> A or 5 </ b> B of the correction cylinder 5 via the pressure sensor 16.
[0075]
As a result, the correction cylinder drive control means 24H operates the correction cylinder 5 for each bending process as described above, and can apply the predetermined pressure d to the table by the correction cylinder 5 (FIG. 8). Step 110 of YES).
[0076]
The operation of the present invention having the above configuration will be described below with reference to FIG.
[0077]
(1) Operations from the input of machining conditions to the start of machining.
[0078]
In step 101 of FIG. 8, processing conditions are input, correction information of the upper table 1 is calculated in step 102, ram information of the upper table 1 is calculated in step 103, and correction information and ram information are calculated in step 104. Remember.
[0079]
That is, when the machining conditions (FIG. 4) described above are input for each bending process via the input / output means 24B (FIG. 1) of the NC device 24, the CPU 24A that has detected the processing conditions (FIG. 1) performs correction information. The calculation means 24F and the ram information calculation means 24D are controlled. Correction information such as the bending load a received by the upper table 1 is received for the correction information calculation means 24F, and the upper table 1 for the ram information calculation means 24D. The ram information consisting of the stroke amounts s1 and s2 is calculated for each bending process.
[0080]
When the calculation is completed, the CPU 24A that detects the calculation again controls the correction information calculation unit 24F and the ram information calculation unit 24D, thereby using the calculated correction information and ram information as a database (FIG. 7). The data is stored in the storage unit 24C (for example, FIG. 5).
[0081]
(2) Operation after starting machining.
[0082]
(2) -A Operation until the punch P contacts the workpiece W.
In step 105 of FIG. 8, the machining is started. In step 106, the correction block 4 is positioned at the deflection center position b. In step 107, the upper table 1 is lowered. In step 108, the punch P contacts the workpiece W. If the contact is not made (NO), the process returns to step 107 and the same operation is repeated. If the contact is made (YES), the process proceeds to step 109.
[0083]
In this case, for example, the flanges F1, F2,... Of the workpiece W having a shape as shown in FIG. 4 are bent in the order of the bending steps 1, 2,. It is assumed that different types of molds P and D are mounted and step bend processing is performed while moving the processing position.
[0084]
Therefore, the operations in steps 106 to 114 in FIG. 8 described below are repeated for each bending process 1, 2...
[0085]
That is, the CPU 24A that has detected that the correction information and the ram information are stored in step 104 of FIG. 8 (FIG. 1) is regarded as the start of processing, instructs the correction block drive control means 24G, and stores in the storage means 24C. The database is searched (FIG. 7), and for example, for the bending step 1, the correction block 4 is positioned at the corresponding deflection center position b1.
[0086]
Thereafter, the CPU 24A (FIG. 1) instructs the ram drive control means 24E to search the database of the storage means 24C (FIG. 7), and in the bending process 1, with the correction block 4 positioned at the deflection center position b1, The upper table 1 is lowered by stroke amounts s11 and s21.
[0087]
(2) -A Operation after the punch P contacts the workpiece W.
In step 108 of FIG. 8, when the punch P contacts the workpiece W (YES), as described above, the process proceeds to step 109. In step 109, the piston 17 of the correction cylinder 5 is lowered, and step 110 is performed. In step S111, it is determined whether or not a predetermined pressure d has been applied. If not (NO), the process returns to step 109 and the same operation is repeated (YES). The workpiece W is bent by P and the die D, the piston 17 of the correction cylinder 5 is raised at step 112, and the upper table 1 is raised at step 113.
[0088]
That is, when the CPU 24A detects that the punch P has contacted the workpiece W via the ram drive control means 24E while the upper table 1 is lowered, this time, the CPU 24A instructs the correction cylinder drive control means 24H, The database of the storage means 24C is searched (FIG. 7), and the piston 17 of the correction cylinder 5 is lowered so that the corresponding predetermined pressure d1 is applied to the lower surface 3A of the gap 3 (FIG. 2) in the bending process 1. Let
[0089]
As a result, the pressure in the correction cylinder 5 increases, and when the CPU 24A detects that the predetermined pressure d1 has been reached via the correction cylinder drive control means 24H, the correction is again made via the correction cylinder drive control means 24H. The predetermined pressure d1 is maintained by stopping the lowering of the piston 17 of the cylinder 5.
[0090]
Then, the CPU 24A continues the lowering operation of the upper table 1 while maintaining the predetermined pressure d1, and performs bending on the workpiece W by the punch P of the upper table 1 and the die D of the lower table 2.
[0091]
In this case, the upper table 1 is applied with the predetermined pressure d1 by the correction cylinder 5 from the time when the punch P contacts the workpiece W, and therefore the deflection amount c of the upper table 1 becomes zero ( 6 (D)) The deflection is corrected, and in this state, the workpiece W is bent by the punch P of the upper table 1 and the die D of the lower table 2.
[0092]
When the bending process is completed, the upper table 1 is lowered by the predetermined stroke amounts s11 and s21 and reaches the bottom dead center.
[0093]
Therefore, after that, the CPU 24A (FIG. 1) raises the piston 17 of the correction cylinder 5 and the upper table 1 through the correction cylinder drive control means 24H and the ram drive control means 24E, thereby bending the upper table 1. The processing for step 1 ends.
[0094]
After the above operation is completed, it is determined in step 114 of FIG. 8 whether or not all the processes are completed. If not (NO), the process returns to step 106, and the same operation is performed for the next bending process 2, for example. Are repeated (YES), all operations are stopped (END).
[0095]
In the present embodiment, the lowering press brake in which the upper table 1 is moved up and down is described in detail. However, the present invention is not limited to this, and the lifting press brake in which the lower table 2 is moved up and down. The left and right drive shafts are AC servo motors M_L, M_RNeedless to say, the same effects as described above can be obtained not only for the press brake of the hydraulic cylinder, but also for the press brake provided with a plurality of correction cylinders 5.
[0096]
【The invention's effect】
As described above, according to the configuration of the present invention, the following effects are achieved.
(1) Since the deflection correction means T has a configuration in which the correction cylinder 5 is simply supported by the correction block 4 which can be positioned within the gap 3, the configuration is simplified.
(2) Since the structure is simple, the deflection correcting means can be easily assembled.
(3) Furthermore, according to the bending apparatus having such a deflection correcting means T, it is only necessary to input the processing conditions, and thereafter, necessary correction information and ram information for each bending process based on the processing conditions. Is automatically calculated, and after the start of machining, the bending correction operation and bending operation are automatically repeated for each bending process based on this information. Can be operated quickly.
[0097]
[Brief description of the drawings]
FIG. 1 is an overall view showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is a diagram showing a positioning control method for a correction block 4, a correction cylinder 5, and an upper table 1 according to the present invention.
FIG. 4 is an explanatory diagram of processing conditions used in the present invention.
FIG. 5 is a detailed view of correction information calculation means 24F constituting the present invention.
FIG. 6 is a diagram showing correction information according to the present invention.
FIG. 7 is a view showing a database of correction information and ram information according to the present invention.
FIG. 8 is a flowchart for explaining the operation of the present invention.
FIG. 9 is a diagram showing deflection deformation of an upper table in the prior art.
FIG. 10 is an explanatory diagram of problems in the prior art.
[Explanation of symbols]
1 Upper table
2 Lower table
3 gap
4 Correction block
5 Correction cylinder
5A Head side oil chamber
5B Rod side pressure oil chamber
6 Piston rod of correction cylinder 5
7 Slider of linear motion guide 9
8 Support plate
9 Linear motion guide
10, 11 Ball screw
12, 15 nut
13 Intermediate plate
14 Die holder
16 Pressure sensor
17 Piston of correction cylinder 5
18-way selector valve
19, 20, 23, 26 Servo driver
21, 22 Position sensor
24 NC unit
24A CPU
24B input / output means
24C storage means
24D Ram information calculation means
24E Ram drive control means
24F correction information calculation means
24G correction block drive control means
24H correction cylinder drive control means
25 Hydraulic source
26 Side plate
D die
M_N, M_L, M_N  motor
P punch
T Deflection correction means
W Work
a Bending load
b Deflection center position
c Deflection
d Predetermined pressure
s1, s2 Stroke amount of upper table 1

Claims (5)

In a bending apparatus that moves one of the upper table to which the punch is attached and the lower table to which the die is attached to bend the workpiece by cooperation of the punch and the die,
In the rectangular gap provided in the table, the correction block is mounted so as to be positioned in the longitudinal direction, and the correction cylinder is supported by the correction block and presses the gap to correct the deflection of the table. Having deflection correction means,
Based on the processing conditions, for each bending process, the bending center position, which is the bending position based on the machine center that maximizes the table deflection, and the predetermined pressure for making the deflection amount at the bending center position zero. Correction information calculating means for calculating correction information comprising:
Correction block drive control means for operating the correction block for each bending step and positioning the correction block at the calculated deflection center position;
A bending apparatus characterized by comprising correction cylinder drive control means for operating a correction cylinder for each bending step and applying the calculated predetermined pressure to the table by the correction cylinder. The correction information calculating unit, and bending load calculation unit, a deflection center position calculating unit, and the deflection amount calculating unit, the bending apparatus according to claim 1, characterized in that is constituted by the pressure calculating unit. The bending load calculation unit calculates the bending load received by the table based on the workpiece material, plate thickness, bending length and die V-groove width, and the deflection center position calculation unit calculates the deflection based on the bending position. The center position is calculated, the deflection amount calculation unit calculates the deflection amount at the deflection center position based on the bending load, the mechanical rigidity value, and the deflection center position, and the pressure calculation unit calculates the deflection amount based on the deflection amount. The bending apparatus according to claim 2 , wherein a predetermined pressure for making the pressure zero is calculated. After completion of the calculation by the correction information calculation means, the correction block drive control means starts the operation of the correction block, and detects that the correction block is positioned at the deflection center position via the rotary encoder. The bending apparatus according to claim 1 , 2 or 3 for stopping the operation of. When the correction cylinder drive control means detects that the punch has contacted the workpiece via the table position sensor in a state where the correction block is positioned at the deflection center position, the correction cylinder starts to operate. when the pressure of the correction cylinder via a sensor detects that it has reached a predetermined pressure, claim 1 to stop the operation of the correction cylinder, 2, 3, or 4 bending apparatus according.

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