JP2006231416A - Tandem press line, operation control method for tandem press line, and workpiece transportation device for tandem press line - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve production efficiency in press forming and to reduce maintenance cost and maintenance frequency. <P>SOLUTION: Rotating speed of a main motor 61 of a second press 3 is controlled such that an angular difference between a press angle of a first press 2 and a press angle of a second press 3 is constant. Further, when a workpiece is unloaded from the first press 2, a workpiece transportation device 10 is controlled based on a press angle of the first press 2. When the work is loaded into the second press 3, the workpiece transportation device 10 is controlled based on a press angle of the second press 3. Further, when the workpiece is transported, the workpiece transportation device 10 is controlled based on a signal from a transportation device control portion 31 for controlling the work transportation device. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention includes a press device for forming a workpiece, and a work transport device for unloading, transporting, and loading the workpiece between two press devices, and arranging a plurality of press devices and adjacent press devices The present invention relates to an operation control method and a tandem press line of a tandem press line in which a workpiece transfer device is disposed. The present invention also relates to a work transfer device for a tandem press line.

  For example, a tandem press line is known as a form of a press that efficiently performs a plurality of forming operations such as drawing, bending, drilling, and edging on a single workpiece. The tandem press line is provided with a plurality of press devices (hereinafter referred to as “presses”) arranged in a line, and the work is conveyed from the upstream press to the downstream press, and is sequentially press-formed by each press. There are cases where the workpiece is conveyed manually or via a workpiece conveying device. Each press is provided with a main motor, and the rotation operation of the main motor is converted into a slide up / down operation (reciprocating operation) via a drive mechanism. Since each main motor is controlled independently, the slide movement of each press is independently performed. Hereinafter, the press and the workpiece transfer device will be described.

[About press]
FIG. 11 is a schematic diagram of a drive mechanism. Here, a drive mechanism of a crank press is shown as an example. A motor pulley 52 is provided on the rotating shaft of the main motor 51, and the motor pulley 52 and the flywheel 54 are connected via a belt 53. The flywheel 54 and the first engagement member of the clutch 55 are connected, and the drive shaft 56 is connected to the second engagement member of the clutch 55. Further, the drive shaft 56 is provided with a brake 57. A part of the drive shaft 56 and the main gear 58 are meshed, and the main gear 58 is fixed to a part of the crankshaft 59. A slide 16 is suspended from a crank portion of the crankshaft 59 via a connecting rod 45.

  According to this drive mechanism, the flywheel 54 is rotated by the main motor 51, and the rotational energy of the flywheel 54 is transmitted to the crankshaft 59 via the clutch 55 and the main gear 58. Then, the crankshaft 59 is rotated, and the rotation operation is converted into the raising / lowering operation of the slide 16. Further, by switching between engagement and release of the clutch 55 and release and brake of the brake 57, the operation and stop of the slide 16 are switched. The drive mechanism may be further provided with a speed change mechanism in which a plurality of gears are combined.

  The slide lifting operation in each press is controlled as follows. When the slide 16 reaches the top dead center, the slide 16 stops at the top dead center by releasing the clutch 55 and braking the brake 57. When the workpiece after molding is carried out from the press processing station and further into the press processing station, the slide 16 is lowered from the top dead center by the engagement of the clutch 55 and the release of the brake 57. When the slide 16 passes the bottom dead center and reaches the top dead center, the slide 16 stops again at the top dead center by releasing the clutch 55 and braking the brake 57. Thus, each press is intermittently operated by repeatedly engaging and releasing the clutch 55 and releasing and braking the brake 57.

  According to the tandem press line, the combination and order of presses can be set according to the application. Moreover, when the press molding by the partial press on a line is not required, the press can be stopped or the press can be used for press molding of other workpieces. Therefore, it can be said that the tandem press line can be applied to various forms of press molding and has a high degree of freedom.

  As a form having a plurality of processing stations arranged in a row with respect to the tandem press line, there is a transfer press. The transfer press has a plurality of processing stations on one slide, and each slide is moved up and down by one main motor. For this reason, the slide lifting operation of each press is synchronized. Therefore, although the production efficiency is high, the degree of freedom is low because the form of pressing is constant.

[Regarding workpiece transfer device]
As a method for conveying a workpiece between presses adjacent to each other, a robot method or a loader / unloader method is known. Here, the robot system is such that an articulated handling robot is installed between adjacent presses, and the workpiece is unloaded from the press in the previous process by this handling robot, and the work is loaded into the press in the next process. It is what. On the other hand, in the loader / unloader system, a loader and an unloader having a link structure are respectively provided on the upstream side surface and the downstream side surface of the press body, and a shuttle carriage is provided between the upstream unloader and the downstream loader. The unloader and the loader are used to carry out and carry in the workpiece, respectively, and the workpiece is transferred to the next process by the shuttle carriage.

  However, in these conventional methods, it is necessary to convey the workpiece by following the intermittent movement of each of the upstream and downstream presses, and in order to prevent interference with a mold or the like during workpiece conveyance. Therefore, there is a problem that the handling speed of the workpiece cannot be increased, and there is a limit in improving the production speed. Furthermore, in the case of the robot system, there is a problem that it is difficult to teach the conveyance path and it takes a long time. In the case of the loader / unloader system, the shuttle carriage is placed between adjacent presses. Since installation is necessary, there is a problem that the apparatus becomes large and a large installation space is required.

In order to solve these problems, the present applicant has previously applied for a tandem press line work transfer method and a work transfer device that can easily teach a work transfer trajectory in a short time and increase the work transfer speed. It has already been proposed as an invention (Patent Document 1 below). The workpiece transfer device of the prior invention is provided with a lift beam that can move up and down in parallel with the workpiece transfer direction, and a carrier and a subcarrier that are movable along the longitudinal direction of the lift beam. And a crossbar having a work holding means.
Japanese Patent Laid-Open No. 2003-200291

  The most effective means for improving the production efficiency of the tandem press line is to operate each press continuously and further to operate the work conveying device following the press. However, there are the following obstacles for such operation.

  For example, it is assumed that press molding is performed by simultaneously lowering each slide of a plurality of presses from the top dead center at the same speed. In this case, there is no problem as long as each slide performs the same stroke operation and returns to the top dead center, but the timing is actually off. This is because the slowdown of each press is different and the cycle of the press operation is different.

  Slow down refers to a phenomenon in which the rotational speed of the flywheel is temporarily reduced, and is an unavoidable phenomenon due to a press molding load or the like. The slowdown is determined according to various factors, such as the energy required for press molding, the capacity of the main motor, the size of the flywheel, etc., but since these factors differ between each press, the slowdown of each press is Different.

  FIG. 12 is a diagram showing the slide position with time, and shows the slide position of each press when adjacent presses are continuously operated. As shown by the waveforms A and B in FIG. 12, even when the predetermined phase difference T1 is set in the sliding operation between adjacent presses and the operation is started, the phase difference gradually increases with the operation due to the effect of the slowdown described above. For example, waveforms A and B ′ are obtained. Since the amount of change in the phase difference is small at the beginning, it is possible to continuously carry out the work from the upstream press and carry the work into the downstream press. However, the amount of change in the phase difference increases with time. If this amount of change increases to some extent, the timing of unloading the workpiece from the upstream press and loading the workpiece into the downstream press cannot be taken, and eventually the line must be stopped halfway.

  Due to such obstacles, the conventional tandem press line has to perform intermittent operation in order to safely and reliably carry in and out the workpiece. For this reason, improvement in production efficiency could not be expected.

  In addition, in intermittent operation, clutch engagement / release and braking by braking are required. Engagement / disengagement of the clutch and braking by the brake are accompanied by a loud noise and wear of the facings provided on the clutch and the brake. If the wear of the facing is severe, the life of the facing will be shortened and the replacement work of the facing will be required. Therefore, the maintenance cost increases.

  In addition, since the invention of the prior application (the above-mentioned Patent Document 1) is proposed only for the hardware configuration of the workpiece transfer device for increasing the workpiece transfer speed in the tandem press line, it is operated independently. In the intermediate conveyance between the two presses, there is room for study on a control technique for efficiently conveying the workpiece by following each press.

  The present invention has been made in view of such a situation, and an object of the present invention is to improve the production efficiency of press molding and to reduce the maintenance cost and the maintenance frequency.

Therefore, the first invention is
In an operation control method of a tandem press line in which a plurality of press devices are arranged and a work conveying device is arranged between an adjacent upstream press device and a downstream press device,
Control the operation of the downstream press device based on a signal corresponding to the operation of the upstream press device,
In the work unloading section, the operation of the work transfer device is controlled based on a signal corresponding to the operation of the upstream press device.

The second invention is the first invention,
Index values indicating the slide positions of press devices adjacent to each other are stored in advance in association with each other,
An index value indicating a slide position is detected for each press device, and a corresponding index value of the downstream press device is obtained based on the detected index value of the upstream press device, and the detected index of the downstream press device is detected. The operation of the downstream press device is controlled so that the value matches the calculated index value of the downstream press device.

The third invention is the first invention,
Each press is operated continuously.

A fourth invention is the first invention,
In controlling the operation of the downstream press device, the speed of a motor provided in the downstream press device is controlled.

The fifth invention
In a tandem press line in which a plurality of press devices are arranged and a work transfer device is arranged between the adjacent upstream press device and the downstream press device,
A press control unit for controlling the operation of the downstream press device based on a signal corresponding to the operation of the upstream press device;
The workpiece unloading section includes a workpiece transfer control unit that controls the operation of the workpiece transfer device based on a signal corresponding to the operation of the upstream press device.

A sixth invention is the fifth invention,
An index value indicating a slide position of press devices adjacent to each other is provided with a storage unit that stores the index value in advance in association with each other,
The press control unit detects an index value indicating a slide position for each press device, obtains a corresponding index value of the downstream press device based on the detected index value of the upstream press device, and detects the detected The operation of the downstream press apparatus is controlled so that the index value of the downstream press apparatus matches the calculated index value of the downstream press apparatus.

A seventh invention is the fifth invention,
Each press is operated continuously.

In an eighth aspect based on the fifth aspect,
The press control unit controls a speed of a motor provided in the downstream press device.

The ninth invention
A tandem press line comprising: a work transport unit disposed between an adjacent upstream press device and a downstream press device among a plurality of press devices; and a control unit that controls the operation of the work transport unit. In workpiece transfer equipment,
In the work unloading section, the control unit controls the operation of the work transfer unit based on a signal corresponding to the operation of the upstream press device.

  According to the present invention, the slide operation of the downstream press is corrected in real time in accordance with the slide operation of the upstream press, and the workpiece unloading / conveying / conveying operation by the workpiece conveying device is performed in accordance with the slide operation of the adjacent press. Since this is done, each tandem press line can be operated continuously, and production efficiency can be greatly improved. When continuous operation can be performed, it is no longer necessary to engage and disengage the clutch and to perform braking by the brake, which are required in the intermittent operation, so that the wear of the facings provided on the clutch and the brake can be reduced. Therefore, maintenance cost and maintenance frequency can be reduced. Further, since there is no need to perform intermittent operation, it is possible to eliminate noise caused by engagement and disengagement of the clutch and braking by the brake.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a front view of a tandem press line according to the present embodiment. FIG. 2 is a side view of the tandem press line according to the present embodiment. FIG. 3 is a front view of the workpiece transfer device. 4 is a cross-sectional view taken along the line AA in FIG.

  The tandem press line 1 of the present embodiment includes first to fourth presses 2 and 3 that are arranged in series from the upstream side (left side of the drawing) to the downstream side (right side of the drawing) with a predetermined interval therebetween. 4, 5 and a material carry-in device 6 arranged on the upstream side of the first press 2 on the most upstream side, a product carry-out device 7 arranged on the downstream side of the fourth press 5 on the most downstream side, and material carry-in The work 8 on the apparatus 6 is transferred / loaded into the processing station of the first press 2 and the work 8 is transferred / transferred / loaded between the processing stations of the presses 2, 3, 4, 5 adjacent to each other. And a workpiece transfer device 13 for transferring and transferring the workpiece 8 from the processing station of the fourth press 5 onto the product carry-out device 7.

  The presses 2, 3, 4, and 5 are each supported by an upright 14 as a main body frame, an upper frame 15 that is arranged above the upright 14 and incorporates a drive mechanism, and is supported by the upright 14 so as to be movable up and down. A slide 16 that is moved up and down via a mechanism, and a bolster 18 that is disposed on the bed 17 so as to be opposed to the slide 16. The upper mold that is attached to the lower end of the slide 16, and the upper end of the bolster 18. The workpiece 8 is configured to be processed by the lower mold to be mounted.

  Here, the detailed structure of the workpiece transfer devices 9 to 13 will be described. Since the basic configuration of each of the workpiece transfer devices 9 to 13 is substantially the same, hereinafter, as a representative example, the configuration of the workpiece transfer device 10 disposed between the presses 2 and 3 will be mainly described. .

  As shown in FIGS. 2 and 4, the workpiece transfer apparatus 10 includes a pair of lift beams 19 and 19 that are spaced apart from each other in parallel on both sides (left and right in the drawing) in the workpiece transfer direction. A rod 20 extending upward along the upright 14 is attached to the upper portion of the lift beam 19. On the other hand, a lift shaft servo motor 22 is mounted on the upper portion of the upright 14 via a support member 21, and a pinion attached to the output shaft of the servo motor 22 meshes with a rack carved in the rod 20, thereby The lift beam 19 is moved up and down by forward / reverse rotation of 22. Here, the lift shaft servomotor 22 is controlled based on a feeder motion set in advance by a control signal from a transfer device control unit 31 described later.

  Each of the left and right lift beams 19 is provided with a carrier (main carrier) 23 having a substantially U-shaped cross section so as to hold the lift beam 19 from below, and the carrier 23 extends along the longitudinal direction of the lift beam 19. It has been moved. Then, as shown in FIG. 4, a pair of linear as a moving means for moving the carrier 23 along the lift beam 19 between both outer side surfaces of the lift beam 19 and the inner side surface of the carrier 23 facing the lift beam 19. A motor 24 is arranged. Linear guides 25 are arranged between the upper outer surfaces of the lift beam 19 and the inner surface of the carrier 23 facing the lift beam 19 and between the lower surface of the lift beam 19 and the bottom surface of the carrier 23 facing the lift beam 19, These three-point supported linear guides 25 are configured to guide the movement of the carrier 23 relative to the lift beam 19. Here, the linear motor 24 is arranged on both sides of the lift beam 19 along the conveyance direction (longitudinal direction), and on the inner surface of the carrier 23 facing the magnet 24a in the conveyance direction (longitudinal direction). The armature (carrier 23) having the coil 24b is linearly moved by the change of the magnetic field generated on the stator (lift beam 19) having the magnet 24a. ing.

  Further, a base plate 23a having a required length extends along the workpiece conveyance direction at the lower portion of the carrier 23 so that the subcarrier 26 can move along the base plate 23a. The moving means of the subcarrier 26 is achieved by a linear motor 27 including a magnet 27a disposed on the lower surface of the base plate 23a along the conveying direction and a coil 27b disposed on the upper surface of the subcarrier 26 facing the magnet 27a. It is configured. Further, linear guides 28 are respectively arranged between the lower surfaces on both sides of the base plate 23a and the upper surfaces of the subcarriers 26 opposite thereto, so that the movement of the subcarrier 26 relative to the carrier 23 is guided by these linear guides 28. It is configured. A pair of subcarriers 26 and 26 facing each other are connected by a cross bar 29, and a plurality of vacuum cups 30 are attached to the lower surface of the cross bar 29, and the workpiece 8 is adsorbed by these vacuum cups 30. It is like that. Here, the linear motors 24 and 27 are controlled based on a feeder motion set in advance by a control signal from a transfer device control unit 31 to be described later, thereby moving the carrier 23 relative to the lift beam 19 along the transfer direction. The movement operation along the conveyance direction of the subcarrier 26 with respect to the carrier 23 is controlled.

  In the workpiece transfer apparatus 10 configured in this way, the vacuum cup 30 is lifted and lowered via the carrier 23, the subcarrier 26 and the crossbar 29 by moving the lift beam 19 up and down by driving the lift shaft servomotor 22. Can be moved. Further, the carrier 23 is moved along the longitudinal direction of the lift beam 19 by driving the linear motor 24, and the subcarrier 26 is offset in the moving direction of the carrier 23 by driving the linear motor 27. 30 can be moved in the workpiece transfer direction. In this way, by controlling two orthogonal drive shaft positions in the vertical direction and / or the transport direction, the movement trajectory of the vacuum cup 30, in other words, the transport trajectory of the workpiece 8 can be controlled.

  Next, control of the first to fourth presses 2 to 5 and control of the workpiece transfer devices 9 to 13 will be described.

[1. Press control]
According to the present embodiment, there are two control methods for controlling the press. Below, it demonstrates as 1st press control and 2nd press control, respectively.

[1-1. First press control]
FIG. 5 is a configuration diagram of a control system according to the first press control.

  The upper frame 15 of the first press 2 has a built-in drive mechanism, and the structure thereof is the same as that shown in FIG. In FIG. 5, the drive mechanism shown in FIG. 11 is further simplified. As described with reference to FIG. 11, the drive mechanism is provided with the flywheel 54, the clutch 55, the brake 57, the main gear 58, and the crankshaft 59. The upper frame 15 is provided with an encoder 91. The encoder 91 detects the angle θ1 of the main gear 58 as a press angle (crank angle) and outputs the detected angle θ1 to the slide control unit 40. The driver 50 controls the rotation speed of the main motor 51 according to the main gear angular speed command Ig output from the slide control unit 40. The main motor 51 rotates the flywheel 54. The configurations of the drive mechanisms, motors, drivers, encoders, and the like of the presses 3 to 5 are the same as those of the first press 2.

  The line control unit 400 controls the tandem press line 1 in an integrated manner, and outputs a speed command to the transfer device control unit 31 (to be described later) and presses the press so that work transfer and press molding are performed in conjunction with each other. The main gear angular velocity command Ig is output to the side slide control unit 40.

  The slide control unit 40 is provided with a first press control unit 41, a second press control unit 42, a third press control unit 43, and a fourth press control unit 44. The slide control unit 40 outputs the main gear angular velocity command Ig to the driver corresponding to the press having the longest rise time. Further, the slide control unit 40 corrects the main gear angular velocity command Ig using the correction signal S1 generated by the first press control unit 41, and outputs the corrected main gear angular velocity command Ig1 to the driver 50 of the first press 2. The slide control unit 40 corrects the main gear angular velocity command Ig using the correction signal S2 generated by the second press control unit 42, and outputs the corrected main gear angular velocity command Ig2 to the driver 60 of the second press 3. Further, the slide control unit 40 corrects the main gear angular velocity command Ig using the correction signal S3 generated by the third press control unit 43, and outputs the corrected main gear angular velocity command Ig3 to the driver 70 of the third press 4. Further, the slide control unit 40 corrects the main gear angular velocity command Ig using the correction signal S4 generated by the fourth press control unit 44, and outputs the corrected main gear angular velocity command Ig4 to the driver 80 of the fourth press 5. .

  The first press control unit 41 receives the detected angle θ1 of the encoder 91 of the first press 2 and generates a main gear correction signal S1 to correct the main gear angular velocity of the main gear 58.

  The second press control unit 42 inputs the detection angle θ1 of the encoder 91 of the first press 2 and the detection angle θ2 of the encoder 92 of the second press 3, and a correction signal S2 corresponding to the difference θ1-2 between the two detection angles. Is generated.

  The third press control unit 43 inputs the detection angle θ2 of the encoder 92 of the second press 3 and the detection angle θ3 of the encoder 93 of the third press 4, and a correction signal S3 corresponding to the difference θ2-3 between the two detection angles. Is generated.

  The fourth press control unit 44 inputs the detection angle θ3 of the encoder 93 of the third press 4 and the detection angle θ4 of the encoder 94 of the fourth press 5, and a correction signal S4 corresponding to the difference θ3-4 between the two detection angles. Is generated.

  Next, the control mode of the second press 3 (the same applies to the third press 4 and the fourth press 5) in the present embodiment will be described.

  FIG. 6 is a diagram showing the slide position with time, and shows the displacement of the slide position when the adjacent first press 2 and second press 3 are continuously operated. A waveform A indicates a periodic change in the slide position of the first press 2, and a waveform B indicates a periodic change in the slide position of the second press 3. The upper ends of the waveforms A and B are the top dead center of the slide, and the lower ends are the bottom dead center of the slide. Hereinafter, a description will be given with reference to FIGS. 5 and 6.

  First, it is assumed that the slide 16a of the first press 2 and the slide 16b of the second press 3 are maintained in a predetermined positional relationship. That is, as shown in FIG. 6, the waveforms A and B are maintained at a predetermined phase difference T1.

  However, if the angle difference between the crank angle of the first press 2 and the crank angle of the second press 3 changes due to a difference in slowdown, for example, a shift occurs in the periodic change of the slide position. For example, a case where the angle difference becomes large will be described with reference to FIG. 6. Waveform B is shifted in the time axis positive direction with respect to waveform A, and the periodic change of the slide position of first press 2 and second press 3 The periodic change of the slide position has a relationship of waveforms A and B ', and the phase difference is T2.

  As shown in FIG. 5, the encoder 91 of the first press 2 detects the crank angle θ1 (the angle of the main gear 58), and the detected crank angle θ1 is output to the first press control unit 41 and the second press control unit 42. Is done. The encoder 92 of the second press 3 detects the crank angle θ2 (the angle of the main gear 68), and the detected crank angle θ2 is output to the second press control unit 42 and the third press control unit 43. The second press control unit 42 calculates the angle difference θ1-2 (= θ1−θ2), and generates a correction signal S2 corresponding to the angle difference θ1-2.

  The slide controller 40 corrects the main gear angular velocity command Ig based on the correction signal S2. Then, a corrected main gear angular velocity command Ig2 is generated and output to the driver 60 in order to make the crank angle of the first press 2 and the crank angle of the second press 3 constant. The driver 60 rotates the main motor 61 in accordance with the main gear angular velocity command Ig2. The main motor 61 is decelerated when the slide operation of the second press is fast, and the main motor 61 is accelerated when the slide operation of the second press is slow.

  Then, as shown in FIG. 6, the waveform B ′ returns to the time axis negative direction with respect to the waveform A, and the periodic change of the slide position of the first press 2 and the periodic change of the slide position of the second press 3 , B, and the phase difference returns to T1.

  The encoders 91 and 92 always detect the crank angles θ1 and θ2, and the second press control unit 42 always calculates the angle difference θ1-2. Therefore, the correction signal S2 is generated in accordance with the change in the angle difference θ1-2, and the sliding operation of the second press 3 is corrected in real time. Therefore, in practice, the cyclic change of the slide position of the first press 2 and the cyclic change of the slide position of the second press maintain the waveforms A and B, and the predetermined phase difference T1 is maintained.

  Similar control is performed between the second press 3 and the third press 4, and similar control is performed between the third press 4 and the fourth press 5.

  The first press control is applied to a press using a main gear, for example, a mechanical press. However, the first press control is applied to a press without a main gear, for example, an electric servo press by using a virtual press angle. be able to.

[1-2. Second press control]
FIG. 7 is a configuration diagram of a control system according to the second press control. In addition, the same code | symbol is attached | subjected to the same element as the control system block diagram shown in FIG. 5, and the description is abbreviate | omitted.

  The first press 2 is provided with a position sensor 95 such as a linear scale. The position sensor 95 detects the position of the slide 16a in the slide operation direction and outputs the detection position P1 to the slide control unit 40. The presses 3 to 5 are also provided with position sensors 96, 97, and 98 for detecting the positions of the slides 16b to 16d.

  The slide control unit 40 is provided with a first press control unit 46, a second press control unit 47, a third press control unit 48, and a fourth press control unit 49.

  The second press control unit 47 stores a displacement characteristic (waveform A) of the slide 16a of the first press 2 and a displacement characteristic (waveform B) of the slide 16b of the second press 3 as shown in FIG. Further, a predetermined phase difference T1 is provided between the two displacement characteristics, and the position of the slide 16b corresponds to the position of the slide 16a and is stored. If this positional relationship is maintained, the two slides 16a and 16b can be continuously operated while maintaining a predetermined phase difference T1. The second press control unit 47 inputs the detection position P1 of the position sensor 95 of the first press 2 and the detection position P2 of the position sensor 96 of the second press 3, and the slide 16b corresponding to the detection position P1 of the slide 16a is input. The corresponding position P2 'is obtained, and a correction signal S2 corresponding to the difference P2-2 between the detected position P2 of the slide 16b and the obtained corresponding position P2' of the slide 16b is generated.

  The third press control unit 48 stores the displacement characteristics of the slide 16b of the second press 3 and the displacement characteristics of the slide 16c of the third press 4, and there is a predetermined phase difference between the two displacement characteristics. Provided, and the position of the slide 16c corresponds to the position of the slide 16b and is stored. If this positional relationship is maintained, the two slides 16b and 16c can be continuously operated while maintaining a predetermined phase difference. The third press control unit 48 inputs the detection position P2 of the position sensor 96 of the second press 3 and the detection position P3 of the position sensor 97 of the third press 4, and the slide 16c corresponding to the detection position P2 of the slide 16b is input. The corresponding position P3 'is obtained, and a correction signal S3 corresponding to the difference P3-3 between the detected position P3 of the slide 16c and the corresponding position P3' obtained for the slide 16c is generated.

  The fourth press control unit 49 stores the displacement characteristics of the slide 16c of the third press 4 and the displacement characteristics of the slide 16d of the fourth press 5, and there is a predetermined phase difference between the two displacement characteristics. It is provided and stored so that the position of the slide 16d corresponds to the position of the slide 16c. If this positional relationship is maintained, the two slides 16c and 16d can be continuously operated while maintaining a predetermined phase difference. The fourth press control unit 49 inputs the detection position P3 of the position sensor 97 of the third press 4 and the detection position P4 of the position sensor 98 of the fourth press 5 and inputs the slide 16d corresponding to the detection position P3 of the slide 16c. The corresponding position P4 'is obtained, and a correction signal S4 corresponding to the difference P4-4 between the detected position P4 of the slide 16d and the corresponding position P4' obtained for the slide 16d is generated.

  Next, the control mode of the second press 3 (the same applies to the third press 4 and the fourth press 5) in the present embodiment will be described.

  At the beginning of the stable operation of the continuous operation, the slide 16a of the first press 2 and the slide 16b of the second press 3 are kept in a predetermined positional relationship. That is, as shown in FIG. 6, the waveforms A and B are maintained at a predetermined phase difference T1.

  However, for example, if the slide position of the first press 2 and the slide position of the second press 3 change due to a difference in slowdown, a shift occurs in the periodic change of the slide position. For example, the case where the phase difference becomes large will be described with reference to FIG. 6. Waveform B is shifted in the positive direction of the time axis with respect to waveform A, and the periodic change of the slide position of first press 2 and second press 3 The periodic change of the slide position has a relationship of waveforms A and B ', and the phase difference is T2.

  As shown in FIG. 7, the position sensor 95 of the first press 2 detects the position P 1 of the slide 16 a, and the detected position P 1 is output to the second press control unit 47. The position sensor 96 of the second press 3 detects the position P2 of the slide 16b, and the detected position P2 is output to the second press control unit 47. The second press control unit 47 obtains the corresponding position P2 'of the slide 16b corresponding to the detected position P1 of the slide 16a, and corrects it according to the difference P2-2 between the detected position P2 of the slide 16b and the corresponding position P2' of the slide 16b. Signal S2 is generated.

  In the slide controller 40, the main gear angular velocity command Ig is corrected based on the correction signal S2. Then, a corrected main gear angular velocity command Ig2 is generated to output the slide position of the second press 3 to P2, and is output to the driver 60. The driver 60 rotates the main motor 61 in accordance with the main gear angular velocity command Ig2. When the slide operation of the second press is fast, the main motor 61 is decelerated, and when the slide operation of the second press is slow, the main motor 61 is accelerated.

  Then, as shown in FIG. 6, the waveform B ′ returns to the time axis negative direction with respect to the waveform A, and the periodic change of the slide position of the first press 2 and the periodic change of the slide position of the second press 3 , B, and the phase difference returns to T1.

  The position sensors 95 and 96 always detect the slide positions P1 and P2, and the second press control unit 47 always obtains the corresponding position P2 'corresponding to the detected position P1, and determines the detected position P2 and the corresponding position P2'. The difference P2-2 is calculated. Therefore, the correction signal S2 is generated in accordance with the deviation between the detection position P2 and the corresponding position P2 ', and the sliding operation of the second press 3 is corrected in real time. Therefore, in practice, the cyclic change of the slide position of the first press 2 and the cyclic change of the slide position of the second press maintain the waveforms A and B, and the predetermined phase difference T1 is maintained.

  Similar control is performed between the second press 3 and the third press 4, and similar control is performed between the third press 4 and the fourth press 5.

  In the second press control described above, the slide position P is used as an index value of the slide position. For this reason, the correspondence relationship between the displacement characteristics of the slide position of the upstream press and the displacement characteristics of the slide position of the downstream press is stored. However, the press angle θ may be used as an index value of the slide position, and the correspondence relationship between the change characteristic of the press angle of the upstream press and the change characteristic of the press angle of the downstream press may be stored.

  Also, index values of the slide position of each press, for example, the correspondence relationship between the slide position P and the press angle θ may be stored as a table.

  The second press control can be applied to any press, for example, an electric servo press or a hydraulic servo press. However, since a press without a main gear outputs another command I that is not the main gear speed command Ig, the command I is corrected.

  As described above, according to the first or second press control of the present embodiment, the slide of the upstream press (first press 2) and the slide of the downstream press (second press 3) have a predetermined phase difference. Since the configuration is such that the press angle or slide position of the downstream press is corrected based on the press angle or slide position of the upstream press so that the operation is maintained, the cyclic operation of the upstream press or the downstream press is performed. Even if the change occurs, the slide position of the downstream press is appropriately corrected according to the slide position of the upstream press. Therefore, continuous operation of the tandem press line is possible.

[2. Control of workpiece transfer device]
FIG. 8 is a configuration diagram of a control system related to the control of the workpiece transfer device. FIG. 9 is a diagram showing a feeder motion.

  In order to avoid interference between the workpiece 8 conveyed by the workpiece conveyance device and the mold, the lifting / lowering (lift-down) operation and conveyance (advance-return) operation of each workpiece conveyance device are shown in FIGS. As shown, the lift shaft servomotor 22 and the linear motors 24 and 27 are controlled based on the stroke and timing set in advance in the transport device control unit 31, that is, the feeder motion. In this embodiment, the feeder motion is a two-dimensional motion in the feed axis direction (conveyance direction) and the lift axis direction (vertical direction), and for each axis (feed axis and lift axis) as shown in FIG. Is determined based on the axial position command value for the press angle set to. According to the feeder motion of this embodiment, the work 8 is sucked from the lower mold of the processing station of the first press 2 on the upstream side at the suction point P and lifted in the lift (L) axial direction, and then the downstream side. The second press 3 is transported in the feed (F) axial direction up to the lower die of the processing station of the second press 3 and is lowered in the lift axial direction so as to enter the lower die. Next, the workpiece transfer device 10 is once lifted upward and moved in the return direction to return to the processing station of the first press 2 on the upstream side, and then lifted again through the standby point R at a slightly lowered position. And it is lowered and returned to the suction point P, and one cycle is completed.

  The first press 2 on the upstream side and the second press 3 on the downstream side are provided with encoders 91 and 92, respectively. The encoders 91 and 92 detect the press angles (crank angles) of the presses 2 and 3, respectively. A value is input to the transport device control unit 31. Specifically, the encoders 91 and 92 detect the number of pulse signals corresponding to the angular velocity of the crank angle, and the number of detected pulse signals is added to the up / down counter in the transport device control unit 31. The number of pulse signals corresponding to the crank angle is counted by this up / down counter. The up / down counter is set so that the count value becomes the original value every time the crankshaft rotates once.

  Further, a reference pulse signal having a predetermined cycle is input from the oscillator 34 to the transport device control unit 31, and this input pulse signal is added to an up / down counter in the transport device control unit 31, thereby counting the number of pulse signals. It has come to be. This oscillator 34, like the encoders 91 and 92 arranged in the upstream and downstream presses 2 and 3, is input to the transport device controller 31 for controlling the lifting and lowering operations of the work transport device 10. Since it has a function of transmitting a signal, it can be called a virtual press angle detector (or virtual cam). The period of the reference pulse signal of the oscillator 34 can be changed as appropriate.

  The transport device control unit 31 performs a required calculation based on input information from the encoders 91 and 92 and the oscillator 34, and sends a command value to each servo amplifier (servo driver) 35, 36, 37, and 38 based on the calculation result. In this way, the lift shaft servomotor 22 and the linear motors 24 and 27 of the workpiece transfer device 10 are controlled. Further, the lift shaft servo motor 22 and the linear motors 24 and 27 are provided with speed sensors (not shown) for detecting the speeds of the motors, and speed signals detected by these speed sensors are input to the transport device control unit 31. As a result, speed feedback can be applied to each of the servo amplifiers 35-38.

  Next, a control mode of the work transfer device 10 (same for the work transfer devices 9, 11, 12, and 13) in the present embodiment will be described.

  First, when the work 8 is unloaded from the first press 2 on the upstream side, the slide 16a of the first press 2 passes through the bottom dead center and enters a rising process in a predetermined press angle range ab (see FIG. 9). The control device 31 outputs a control signal to each of the servo amplifiers 35 to 38 based on a signal from the encoder 91 attached to the first press 2. The workpiece transfer device 10 processes the vacuum cup 30 by moving the lift beam 19 and moving the carrier 23 and the subcarrier 26 in the feed direction so as to synchronize (follow) the movement of the first press 2. After moving the station into the lower mold and holding the workpiece 8, an operation of unloading the workpiece 8 from the lower mold is performed (synchronized section with the upstream press).

  Next, after this synchronization section ends, in other words, after the predetermined press angle range a to b is reached, until the start point c of the synchronization section with the next downstream second press 3 is reached. In bc (self-running section), based on a signal from the oscillator 34, a control signal is output from the transport device control unit 31 to each of the servo amplifiers 35 to 38. More specifically, the free-running section is a preparation section before entering the synchronous drive with the downstream second press 3, and a signal from the encoder 92 attached to the downstream second press 3 and an oscillator Based on the deviation from the signal from 34, each servo amplifier 35-38 is controlled so as to gradually reduce the deviation. Thus, even if the upstream and downstream presses 2 and 3 are operated at independent speeds, the operation speed of the work transfer device 10 is gradually adjusted to the operation speed of the next second press 3 in the preparation section. Therefore, the movement of the work transfer device can be controlled more smoothly, and the line speed can be improved. Further, even if the upstream and downstream presses 2 and 3 are operated with a phase difference, they can be handled by adjusting the movement of the work transfer device in the preparation section.

  Thereafter, in the press angle range cd after the end of the self-propelled section, this time, based on the signal from the encoder 92 attached to the second press 3 on the downstream side, the servo amplifier 35 The control signal is output to ˜38, and the workpiece conveying device 10 moves up and down the lift beam 19 and moves the carrier 23 and the subcarrier 26 in the feed direction so as to synchronize (follow) the movement of the second press 3. As a result, the vacuum cup 30 carries the workpiece 8 into the lower mold of the processing station (synchronized section with the downstream press).

  The return process after the work 8 is carried into the lower die of the second press 3 on the downstream side is substantially the same as the transfer of the work 8 in the feed direction described above, and the return process with the downstream second press 3 is performed. After the synchronization section, control is performed such that the self-run section (including the standby point R) is entered and the synchronization section with the upstream first press 2 is entered.

  As described above, according to the workpiece conveyance control of the present embodiment, the encoder 91 attached to the presses 2 and 3 to be loaded and unloaded at the time of loading and unloading the workpieces to and from the presses 2 and 3 (synchronized section). , 92 is controlled to synchronize with the movement of the slide 16 in the target presses 2 and 3 on the basis of the press angle signal from 92, and on the other hand, self-propelled after the work loading / unloading operation is completed. In the section, since the workpiece transfer device 10 is controlled based on a signal from the oscillator (virtual press angle detector) 34, the upstream first press 2 and the downstream second press 3 are respectively Even in the case of independent operation, the workpiece transfer device 10 can be operated without any trouble. Therefore, the excellent effect that the line speed of the tandem press line 1 can be remarkably improved is provided. In addition, there is an advantage that it is not adversely affected by disturbances such as vibration during the press molding of the workpiece 8.

  Next, the positional relationship that changes with the passage of time between the adjacent press and the workpiece transfer device will be described.

  FIG. 10 is a diagram showing the slide position of the adjacent press and the position of the workpiece transfer device over time. A waveform A shows a periodic change in the slide position of the first press 2, a waveform B shows a periodic change in the slide position of the second press 3, and a waveform C shows a periodic change in the position of the work transfer device 10. It shows a change. The upper ends of the waveforms A and B are the top dead center of the slide, and the lower ends are the bottom dead center of the slide. The upper end of the waveform C is a processing station for the first press 2, and the lower end is a processing station for the second press 3. Hereinafter, the operation of the slide 16b of the second press 3 and the operation of the workpiece transfer device 10 will be described with reference to the operation of one stroke of the slide 16a of the first press 2.

At time t1, the slide 16a of the first press 2 reaches top dead center. At this time, the slide 16b of the second press 3 is in the ascending process, and the work conveying apparatus 10 finishes unloading the work from the processing station of the first press 2 and is in the work conveying process to the second press 3 side.
At time t2, the slide 16b of the second press 3 reaches top dead center. At this time, the slide 16a of the first press 2 is in the downward stroke, and the workpiece transfer device 10 is in the workpiece transfer stroke to the second press 3 side.
At time t3, the workpiece transfer device 10 carries the workpiece into the processing station of the second press 3. At this time, the slide 16a of the first press 2 and the slide 16b of the second press 3 are in the downward stroke, and the slide 16b of the second press 3 is located near the top dead center.
At time t4, the work transfer device 10 starts waiting at the standby point. At this time, the slide 16a of the first press 2 and the slide 16b of the second press 3 are in the downward stroke.

At time t5, the slide 16a of the first press 2 reaches the bottom dead center. At this time, the slide 16b of the second press 3 is in the downward stroke, and the workpiece transfer device 10 is in a standby state.
At time t6, the slide 16b of the second press 3 reaches the bottom dead center. At this time, the slide 16a of the first press 2 is in the ascending stroke, and the work transfer device 10 starts to move toward the first press 2 again.
At time t7, the workpiece transfer device 10 carries the workpiece from the processing station of the first press 2. At this time, the slide 16a of the first press 2 and the slide 16b of the second press 3 are in the ascending stroke, and the slide 16a of the first press 2 is located near the top dead center.
At time t8, the slide 16a of the first press 2 reaches the top dead center again.

  According to the present embodiment, the slide operation of the downstream press is corrected in real time in accordance with the slide operation of the upstream press, and the work unloading / conveying / conveying operation by the work conveying device in accordance with the slide operation of the adjacent press. Therefore, each tandem press line can be operated continuously, and the production efficiency can be greatly improved. When continuous operation can be performed, it is no longer necessary to engage and disengage the clutch and to perform braking by the brake, which are required in the intermittent operation, so that the wear of the facings provided on the clutch and the brake can be reduced. Therefore, maintenance cost and maintenance frequency can be reduced. Further, since there is no need to perform intermittent operation, it is possible to eliminate noise caused by engagement and disengagement of the clutch and braking by the brake.

  Further, according to the present embodiment, when synchronizing the operation of the work transfer device with the operation of the downstream press device, the operation of the work transfer device can be controlled more smoothly and efficient press working can be realized. it can.

  The present invention can be applied to a tandem press line provided with a plurality of press devices and a workpiece transfer device disposed between adjacent press devices.

FIG. 1 is a front view of a tandem press line according to the present embodiment. FIG. 2 is a side view of the tandem press line according to the present embodiment. FIG. 3 is a front view of the workpiece transfer device. 4 is a cross-sectional view taken along the line AA in FIG. FIG. 5 is a configuration diagram of a control system according to the first press control. FIG. 6 is a diagram showing the slide position over time. FIG. 7 is a configuration diagram of a control system according to the second press control. FIG. 8 is a configuration diagram of a control system related to the control of the workpiece transfer device. FIG. 9 is a diagram showing a feeder motion. FIG. 10 is a diagram showing the slide position of the adjacent press and the position of the workpiece transfer device over time. FIG. 11 is a schematic diagram of the drive mechanism. FIG. 12 is a diagram showing the slide position over time.

Explanation of symbols

2 ... 1st press, 3 ... 2nd press, 4 ... 3rd press, 5 ... 4th press,
16a to 16d ... slide, 31 ... transport device controller, 40 ... slide controller,
41, 46 ... 1st press control part, 42, 47 ... 2nd press control part,
43, 48 ... third press control unit, 44, 49 ... fourth press control unit,
91, 92, 93, 94 ... encoder, 95, 96, 97, 98 ... position sensor

Claims (9)

In an operation control method of a tandem press line in which a plurality of press devices are arranged and a work conveying device is arranged between an adjacent upstream press device and a downstream press device,
Control the operation of the downstream press device based on a signal corresponding to the operation of the upstream press device,
An operation control method for a tandem press line, wherein the operation of the workpiece transfer device is controlled based on a signal corresponding to the operation of the upstream press device in the workpiece unloading section. Index values indicating the slide positions of press devices adjacent to each other are stored in advance in association with each other,
An index value indicating a slide position is detected for each press device, and a corresponding index value of the downstream press device is obtained based on the detected index value of the upstream press device, and the detected index of the downstream press device is detected. 2. The operation control method for a tandem press line according to claim 1, wherein the operation of the downstream press device is controlled so that the value matches the calculated index value of the downstream press device. The operation control method for a tandem press line according to claim 1, wherein each press device is operated continuously. 2. The operation control method for a tandem press line according to claim 1, wherein when controlling the operation of the downstream press device, the speed of a motor provided in the downstream press device is controlled. In a tandem press line in which a plurality of press devices are arranged and a work transfer device is arranged between the adjacent upstream press device and the downstream press device,
A press control unit for controlling the operation of the downstream press device based on a signal corresponding to the operation of the upstream press device;
In the work unloading section, a tandem press line comprising: a work transfer control unit that controls the operation of the work transfer device based on a signal corresponding to the operation of the upstream press device. An index value indicating a slide position of press devices adjacent to each other is provided with a storage unit that stores the index value in advance in association with each other,
The press control unit detects an index value indicating a slide position for each press device, obtains a corresponding index value of the downstream press device based on the detected index value of the upstream press device, and detects the detected 6. The tandem press line according to claim 5, wherein the operation of the downstream press apparatus is controlled so that the index value of the downstream press apparatus matches the calculated index value of the downstream press apparatus. The tandem press line according to claim 5, wherein each pressing device is operated continuously. The tandem press line according to claim 5, wherein the press control unit controls a speed of a motor provided in the downstream press device. A tandem press line comprising: a work transport unit disposed between an adjacent upstream press device and a downstream press device among a plurality of press devices; and a control unit that controls the operation of the work transport unit. In workpiece transfer equipment,
In the work unloading section, the control unit controls the operation of the work transfer unit based on a signal corresponding to the operation of the upstream press device. A work transfer device for a tandem press line.

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