DE3008035A1 - Synchronised sheet metal press line - changes speed of follow-up presses between limits by upper and lower on-off controller - Google Patents

Abstract

A synchronised drive of a press line for forming sheet metal parts in several stages reduces the cost compared with presses operating with single stroking. The design extends the service life of the drives with the follow-up presses speed adjusted by a two-position controller's switching between a max. and min. speed limits. The switching takes place within the set limits by reference to the phase position of the main press. The deviation sensed by the controllers is monitored by a slip free loop connecting two presses with a feeler roller connected to two switches for min. and max. speed change-over.

Description

Press line

The invention relates to an automatic press line for Production of sheet metal parts in several work stages, consisting of a head press and several subsequent presses, each with its own speed actuator that synchronizes are operated in a permissible range of their phase relationship to one another, with on each press has a feed device and a removal device and also a transport device between adjacent removal and supply devices can be arranged.

There are already numerous variants of automatically operated press lines known, which are based essentially on two, in principle, different systems lie. One system includes automatic, synchronized press lines with presses operated in continuous stroke on the basis of a strict cycle system for transporting the workpieces from station to station through the entire line, such as e.g. in DE-Offenlegungsschrift 1 463 080; 1,602,570; U.S. Patent 3,199,439.

A prerequisite for this is full synchronization of all presses with a certain close tolerance of the phase position, based on the crank angle of all presses and controls of the drives compared to a master unit or to Head press, how they are implemented by complex controls, as in DL 95948 and DE-Auslegeschrift 1563803, 1752O45, 1763397, DE-Offenlegungsschrift 1777355 is described.

A disadvantage of such press lines is that they have the complete engine flywheel drive in its speed according to a reference variable change continuously or in stages.

This requires a lot of electronic control and regulation technology.

In order to achieve short settling times for the large moments of inertia, i.e. maintaining the angle tolerance during operation is an oversizing of the Main drives of the presses compared to presses working individually for calibration the acceleration and deceleration torques required for the control.

In addition, such a regulation requires the use of expensive thyrister-controlled 4-quadrant drives. Due to the complexity of such press lines for their maintenance, upkeep and retrofitting for the user a lot of effort as well as highly qualified personnel required, which is actually contrary to the robust operating conditions in high-performance press shops, to the second system include automatic press lines in which all presses are operated in a single stroke such as

in DE-OS 2209 233 and in the magazine Sheet Metal Industries, March, 1962, pp. 209-211, or where the head press in continuous stroke and the subsequent presses are operated in a single stroke, as described, for example, in DE-AS 1271 067.

These press lines also have a cycle system for transporting them of the workpieces required from station to station. The control is carried out by a relatively simple sequence control. The disadvantage of these press lines is there in a lower performance compared to synchronized press lines and A maximum load on the main and auxiliary drives, such as the clutch and brake as well as drive gears of the automation equipment. This maximum load is subject to very high wear, increased energy consumption and a high level of noise connected, The aim of the invention is to achieve the same performance parameters, as in the case of previously known synchronized press lines, the production technology Production costs, operating costs and maintenance and repair costs for the user compared to the known technical solutions.

Based on the aim of the invention, the problem arises of a press line to create compared to the previously known synchronized press lines a much lower control effort required and the use in general common single addresses with normally dimensioned drives is possible and opposite a press line with presses operated in single stroke or with presses operated in continuous stroke Head press and single-stroke follow-up presses result in higher productivity Reduction of the downtimes occurring between the individual press strokes and with a simultaneous reduction in the switching frequency of the presses and automation equipment and thus an increase in the service life of the highly stressed assemblies, such as Clutch and brake as well as drive gear of the automation equipment accessible is.

According to the invention, the object is achieved by the characterizing features of the invention claim solved.

For the synchronization of the presses within a permissible range their phase relation to each other are the fol & e presses with a two-point controller equipped in addition to the existing speed actuator. That’s the setting an upper and lower limit speed within the Speed adjustment range depending on the phase position of each subsequent press to the head press or each press to theirs previous press guaranteed. As the actuator of the two-position controller is a Double clutch arranged between the flywheel and crankshaft with two downstream different gear stages for the upper and lower limit speed.

The phase position, i.e. the actual value of the two-position controller, is set on the Feed device of each subsequent press to the removal device of the head press or to the removal device of the previous press or directly on each press determined.

The control deviation, i.e. the set-actual value comparison of the two-position controller, is formed by means of a loop that is driven by two slip-free presses will. It is possible to create a loop between the head press and each subsequent press or to form between each press and its previous press, the loop becomes scanned via a feeler roller, which leads to 2 switches, the upper and the Switch lower limit speed.

In addition, the system deviation between the presses can vary according to both Variants with an evaluation circuit that controls the actuators for the upper and lower Speed limit switches, are formed.

This is done by recording the positive or negative deviations of the Phasing necessary via one or two switches on each press.

In the following, the invention will be based on an exemplary embodiment with various Solution variants are explained in more detail. The accompanying drawings show possible solutions of the subject matter of the invention.

They show: Fig, 1.1. Press line from head press with several subsequent presses each with its own speed actuator, which is synchronized in a permissible Are operated in the range of their phase position to each other, with a feed and removal device is arranged, wherein the first subsequent press with the actuator Double clutch equipped with two gear stages between the flywheel and crankshaft is.

Fig. 1.2. Representation of the speed ratios when operating a Press line, the subsequent presses between an upper and lower limit speed can be controlled or regulated within the speed setting range.

Fig. 2.1. Block diagram of the functional principle of a press line with speed actuators and synchronization of the phase position by means of a two-position controller according to Fig. 3.4.

Fig. 2.2. Block diagram of the functional principle of a press line with speed actuators and synchronization of the phase position by means of a two-position controller according to Fig. 3.2.

Fig.3.1. Schematic representation of the formation of the control deviation of the phase position by means of two switches on the head press and one switch each on the subsequent press with evaluation circuit of the phase position between the head press and each subsequent press.

3.2. Schematic representation of the formation of the control deviation of the phase position by means of a switch per press with evaluation circuit of the phase position between Head press and neither pole press.

Fig. 3.3. Schematic representation of the formation of the control deviation of the phase position by means of a switch on each press and by means of a second switch on each second press and an evaluation circuit of the phase position between each one Press and their previous press.

Fig. 3.4. Schematic representation of the formation of the control deviation of the phase position over loop.

The following is noted in advance for all features according to the invention, such as from Fig. 1.1. visible for all solution variants: to adapt to different ones technological working conditions is advantageous cs, each of the arranged in the street Presses can be equipped with a variable-speed drive. It is in increasing Dimensions given preference to direct current drive. The motor is controlled often via single-quadrant thyristor controls. The adjustment range of the stroke or The speed nrnin to nmax of such a press line is in the ratio of about 1: 2.

However, the number of strokes is not the same as the different ones Work withdrawal of the presses and the positional inaccuracies for the drives occurring Phase differences.

This change in the phase position of the presses to one another occurs, too if the start of the phase position of the presses took place without a phase difference. With everyone technological switch to a different workpiece occur new different Work withdrawals, which in turn feel to other phases.

Due to the inventive solution, the subsequent presses 5 r.ftt an upper one and lower limit speed b and j are equipped by means of a two-point control the different phase positions of the following presses 5 to the head press 4 or to the respective previous press 4 or 5 balanced.

The feeding of the sheet metal blanks to the feeding device 1 of the head press 4 takes place by means of a blank feed device 27 known per se adjacent presses 4; 5 a clocked transport device 22 is arranged in each case.

The removal device 2 of the head press 4 transfers the workpiece 3 on the loading area of the transport device 22. The transport device 22 conveys of the workpiece 3 clocked to the removal location 7. The transport device 22 can both from the upstream and downstream press 4; 5 driven or

be operated clocked by means of self-propulsion. Depending on the type of executed drive of the transport device 22 is the transfer point from press 4 or 5 to press 5 either on the loading area or on the de-hemming area 7 of the transport device 22.

If no transport device 22 is present, then this is the deposit station the removal device 2 at the same time the loading station of the feed device 1.

Result from the speed ratios when operating the press line the size of the upper and lower limit speed 8 and 3 ziun. Speed adjustment range 11, as in Fig. 1.2. shown, from the transmission ratio of the gear stages 17, 15.

As further from Fig. 1.2. emerges from the head press 4 other mean stroke rates in the range of α and ß for the speed setting range 11, which is specified by the setpoint S'dK, than for the following presses 5 with the mean number of strokes γ, #, #, #. The change in the mean number of strokes will be caused by stroke time differences that lead to these phase shifts.

The characteristic feature of this tax principle is that that the number of strokes of the subsequent presses 5 compared to the average number of strokes of the head press 4 oscillates at intervals between an upper and a lower limit speed 8 and 9. The differences between the mean number of strokes or the head press 4 to the upper and lower Limit speeds 8 and 9 of the following presses 5 are only approximately constant, since the upper and lower limit speed is formed by a constant speed jump i.

This jump in speed i can be used for all subsequent presses 5 of the press line same as, for example, in Fig. 1.2. shown as well as for each of the individual Subsequent presses of the press line can be specified differently. Due the different work withdrawals of the presses 4, 5 as well as setting inaccuracies there are differences in the mean number of strokes α, ß on the head press 4 and γ, #, #, # on subsequent presses 5. The presses 4, 5 are equipped with speed actuators, one-quadrant thyristor drives 14, preferably fed via power converters. According to the technological conditions, the press line is used for all presses a similar setpoint within a speed setting range 11 5WK or S SWF1 .... SWFn predetermined by means of a central setpoint generator 10.

In the drawings 2010 and 3.4o there are design variants for the Synchronization of the phase positions in press lines with two-point controllers shown. The actuator of the controller in the subsequent press F1 according to Fig. 1.1. consists of one Double clutch 13, through which two different gear stages 1 /; 18 alternately be switched. The required gear ratio of the two gear stages 17; 18 to each other results from the mean number of strokes of the head press 4 with the smallest Speed nmin. The Doppelkupplund 13 is expediently between the flywheel 19 and the crank manner 20 of the subsequent presses j arranged so that the stored Energy of the flywheel 19 for rapid acceleration to the higher speed or the inertia of the flywheel 19 for braking the moving masses on the lower speed is used.

The 1o embodiment of a synchronization of the phase position in Press lines with a two-point controller is shown in Fig.

2.1. and Fig. 3.1. shown.

To form the control deviation of the phase position of the subsequent presses 5 An evaluation circuit 21 assigned to each subsequent press 5 is connected to the head press 4 on the input side in operative connection with one switch 6 on each subsequent press complex and on the output side with the actuator of the double clutch 13th also are all Evaluation circuits on the input side with a switch 6 and 34 on the head press tied together. All switches b are controlled by a control cam, preferably acting over 180 operated, which are in connection with the crankshaft 20 of the associated press.

If a subsequent press 5 is not running synchronously, run to the head press 4 the husgang signals of the switches 6 assigned to these presses are also out of phase into the corresponding evaluation circuit. By means of the AND gates 29 and 30, the direction of the phase shift is determined from this and lower switching limit of the phase shift, the switch 34 is provided, which is why this is actuated via a control cam that acts more than 1800, which is shown in Connection with the crankshaft AG of the head press is. The control curve of the switch 34 of the head press 4 is preferably set symmetrically to that of the switch b. All switches C and their associated control cams are arranged so that they are at Synchronous operation are operated at the same time. If a follow-up press 5 becomes a larger one Phase shift as half the difference between the effective control cams o or 34 reached, the pulse sequence formed in the AND gate 23 or 30 is transferred to the downstream bistable multivibrator 31 output and acts as a continuous signal on the corresponding Output associated actuator 25 or 26 for switching on the upper or lower Limit speed 8 or 9.

Another variant of the formation of the Xegel deviation in the controller Fig. 2.1. is in Fig. 3.2. shown.

The switch 34 from FIG. 3.1. and the associated inputs the AND gate 29 or 30 by a pulse width reduction 32, which consists of a There is a delay element and an AND gate, replaced. This achieves that only from a certain pulse width, the permissible phase shift the pressing corresponds to the pulse sequence formed by the AND gates 29 and 30, respectively is further processed.

In Fig. 3.3. is an embodiment example with the same OFF value circuit 21 as in Fig.3.1. shown. Thereby the phase shift of all presses is determined for the previous press and acts in the same way as in Fig. 3.1.

regulates the speed or phase position of the associated press. As a result, switch 34 is only used for 2 adjacent subsequent presses and is therefore present several times.

The 2nd embodiment of a synchronization of the phase position in Press lines with a two-point controller is shown in Fig.

2.2. and 3.4. shown. In the device for the formation of the cone deviation the phase position by means of loop 33 is made up of an electric wave from a Drelimeldergeber 12 connected to the crankshaft and one Resolver receiver 15, the phase position of each subsequent press 5 to the head press 4 or to the previous press slip-free on one formed by a delicate chain Transfer loop. The phase shift of the presses shown in the loop 23 to each other is via a roller 24 on two switches 7, which are set to the permissible positive or negative phase shift are set, transferred.

The outputs of the switches 7 act via the bistable multivibrator 31 to the actuators 25 and 26 to switch on the lower or upper limit speed 8 or 9.

L e r s e i t e

Claims (6)

Invention claim: 2 press lines, consisting of a head press and several subsequent presses, each with one i! Drives that are synchronized with each other are operated in a permissible range of their phase position, with each press a feed device and a removal device is arranged and between A transport device is also arranged adjacent to the removal and supply system can be, characterized in that the speeds of the subsequent presses (5) are additional to the speed actuator through a two-position controller jump between one upper and lower limit speed (8; 9) within the speed setting range (11) depending on their respective phase relation to the head press (4) or to its previous one Press (4 or 5) are adjustable. 2. Press line according to item 1, characterized in that as an actuator of the two-point controller has a double clutch (13) between the flywheel (19) and the crankshaft (20) with two different gear stages (17; 18), which can be activated by shifting form the upper and lower limit speed (8; 9) for synchronizing the phase position, is arranged. 3. Press line according to item 1 and 2, characterized in that for Formation of the control deviation of the phase position of two presses to each other a loop (23) is used, which is driven by both without slipping, the upper one and the lower position of the loop is assigned the upper and lower limit speed (8; 9) which is scanned by switch (7). 4. press line according to item 1 and 2, characterized in that for Formation of the control deviation for the phase position of the pole presses (5) to the head press (4) or each press (5) to its previous press (4; 5) in each case a switch (6) is arranged on each press (4; 5) with a control cam acting via i800, which is in operative connection via an evaluation circuit (21), each consisting of one AND gate (29; 30) to determine the positive or negative deviation the phase position each with a downstream pulse width reduction (32), consisting from an AND gate with an upstream delay element, its output signals the upper or lower limit speed (8; 9) via a bistable multivibrator (31) switch via the actuators (25; 26), 5. Press line according to point 1 and 2, marked in that to form the system deviation of the phase position of the following presses (5) for the head press (4) two switches (b; 34) with a control cam acting over 1800 on the head press (4) and one switch (6) each with a control cam acting over 1800 is arranged on each subsequent press (5) or that to form the control deviation for the phase position of each press (5) to its previous press (4; 5) on each second press two switches (6; 34) each with a control cam acting over 1800 and on the other presses (4; 5) å e a switch (U) with one over 1800 acting Control cam are arranged, which are in operative connection with an evaluation circuit (21) stand, each consisting of an AND gate (29; 30) to determine the positive or negative deviation of the phase position as well as for pulse width reduction (32), their Output signals via a bistable multivibrator (31) the upper and lower limit speed (8; 9) Switch via the actuators (25; 26). 6. Press line according to point 1 and 2, 4 and 5, characterized in that that the switch (6; 34) to form the system deviation of the phase position at the removal device of the head press (4) and on each feed device of each subsequent press (5) or that the switches (6; 34) to form the control deviation of the phase position on the feed device of every second press and on the removal device of their preceding press are arranged.