EP1149697B1 - Method for driving a printing press with two individual drives - Google Patents

Description

The invention relates to a method for operating a printing press, in particular a sheet-fed offset printing press, according to the preamble of patent claim 1.

In sheet-fed offset printing presses, the cylinders of the printing units and the cylinders and drums serving for sheet transport are driven by a continuous gear train. In this gear train, particularly in the case of a large number of printing units, very large load moments occur, which cause a torsion of the gear train between the individual printing units.

To reduce load-dependent printing errors of the printing press, is in accordance with the DE 42 10 988 A1 a device for controlling a multi-motor drive of a printing press, in which the printing press has a continuous gear train and a plurality of individual electromotive drives, which feed into the gear train. At each power-feeding single drive the instantaneous position of the electric motor is measured in the form of a rotation angle and fed to a control device, which includes the rotational angle differences between two adjacent in the power flow of adjacent motors on their power flows. Depending on the determined rotational angle difference, the actuators of the electric motors are controlled such that the elastic rotation in the gear train of the drive of the printing press and thus the power flows are kept constant.

Despite the performance monitoring and evaluation of the individual drives, due to the elasticity and inertia of the gear train can always come back to the tooth flanks of the gears within the gear train, resulting in Passerfehlem and Doublieren the printed image on the fabric to be printed.

A method according to the preamble of claim 1 is known from EP-A-0904934 known. With regard to further prior art is on the DE-A-19826338 directed.

The invention has for its object to provide a novel method for operating a printing press. According to the invention, this object is achieved by a method according to claim 1.

An advantage of the invention is that the actual rotation in the gear train of the printing press is measured and used to set a bias of one of the individual drives relative to the second single drive. This ensures that all interlocking tooth flanks of the gears of the gear train just abut each other and thus always a minimum positive load is transmitted to the gear train. An unnecessarily strong distortion of the gears against each other is reliably avoided and prevented increased wear in the gear transmission.

In one embodiment, the rotational angle difference of the gear train is determined before the start of the printing process as a function of a predetermined operating state of the printing press and biased at least one single drive during the printing process by this rotational angle difference.

Advantageously, after adjustment of the predetermined operating state of the printing machine, the gear train is moved by at least one of the two individual drives in a predetermined direction of rotation, wherein the difference in the rotational position within the gear train is determined by the gear train is moved until a constant rotation angle difference is determined in multiple measurement ,

This initialization process automatically achieves a constant angular difference as a function of a specific load condition of the printing press for each operating case of the printing press. The load state is characterized in particular by the machine speed of the printing press, the color in the inking units and the printing state of the printing units. For each load situation of the printing press, a bias voltage of the single drive can thus be determined.

In an advantageous development, the position of the at least one position-adjustable single drive is determined before the movement of the gear train and after reaching the constant angular difference of the individual drive, wherein from the two positions a rotational angle difference of the individual drive is determined, wherein the sum of the rotational angle difference of the gear train and the rotational angle difference the at least one individual drive, the tension is determined by which the individual drive is biased during the printing process.

Due to the bias of the at least one position-adjustable single drive, it comes as a result of the elasticity of the gear train and the existing tolerances to a defined tension of the gear train in which the backlash of the gear train is moved out at each angular position.

The accuracy of the torsion preset of the gear train is improved when an additional rotational angle difference is determined, which is determined from a predetermined operating load and / or the Räderzugsteifigkeit.

According to the invention, two individually actuable individual drives are connected to a control unit, wherein the individual drives feed at two different points of the printing machine in a continuous gear train, which is coupled to the subunits of the printing press, with a position-adjustable single drive can be acted upon by the control unit with a setpoint, whereby the Gear train between the two individual drives can be prestressed by a predetermined angle. To improve the tooth flank of the gears of the gear train position sensors are arranged at two different positions within the gear train, which are connected to the control unit and provide the angular position of the gear train in these positions corresponding signals to the control unit, which determines a position setpoint depending on these angular positions, with which a single drive during the printing process can be acted upon.

In one embodiment, particularly accurate results on the rotation of the gear train are achieved when the angular position of two neighbors in the gear train arranged gears is detected, each position sensor per gear rotation outputs a signal from which the control unit calculates a rotation angle difference at predetermined operating conditions.

The play of the tooth flanks of the gears is then reliably prevented when the control unit acts on the at least one individual drive with a desired value, which can be determined from the rotational angle difference of the gear train and a rotational angle difference of the individual drive.

By this procedure, it is possible that all components of the printing press are fed by two individual drives, each individual drive via the gear train drives a predetermined number of subunits of the printing press.

According to one embodiment of the invention, it is provided that each drive for an electric motor has its own, independent speed control loop. These speed control loops are supplied with identical speed basic setpoints. With the exception of a master drive, each follower drive receives another setpoint, the additional speed setpoint, which is formed by a differential angle controller assigned to the follower drive.

The actual value of each of these differential angle controllers can be the difference formed from the actual angles of the respective follower drive and an adjacent follower drive or the difference formed from the actual angles of the respective follower drive and the master drive. The master drive does not necessarily have to be adjacent to the considered slave drive. Alternatively, the difference of the actual angles can also be realized by means of a subtraction of actual speeds of two drives with subsequent integration to determine a differential angle. Again, either the actual speeds of the relevant and an adjacent follower drive or the relevant follower drive and the master drive can be used for subtraction.

If necessary, the control concept can be extended by a current or torque precontrol in each or only in individual control loops. For this purpose, pre-control currents or torques are calculated from the manipulated variables of the differential angle controllers. These pilot control quantities are applied as additional setpoints to the current or torque controllers of the respective follower drives.

The basis for the acquisition of the actual variables (actual angle and / or actual speeds) are absolute encoders (encoders) or incremental encoders with reference signal for determining the absolute position.

At least two sensors may be arranged in the gear train at different positions to determine fixed values for setting the target values for the differential angle controllers, which provide angle information depending on variable operating states of the printing machine (for example, depending on speed, temperature). Basic values for the differential angle adjustment of the individual drive axes relative to one another can be determined with the aid of a multiplicity of temporarily varied nominal differential angles and stored as static nominal value specification in the differential angle controllers.

The determination of a setpoint specification for the differential angle controller can also be based on other different fundamentals, eg. For example: by other fixed values or by any motion variables (angular velocities or accelerations) or by force variables (drive and cutting torques) or by electrical variables (drive currents, voltages) as well as combinations of these variables. As a result, a dynamic change in the differential angle setpoint value can be achieved in order, for example, to be able to optimize the register differences between the individual printing units in the event of machine speed changes.

• Durch den Einsatz von Längswellen im Antriebsstrang einer Druckmaschine wird lediglich eine feste, unveränderbare Versteifung durch einen fest eingestellten Differenzwinkel erreicht. Demgegenüber bietet die Differenzwinkelregelung die Möglichkeit, veränderliche, dem Druckauftrag angepasste Steifigkeiten nachzubilden. Diese Veränderungen können während des Druckbetriebs durch entsprechende Algorithmen, die in der Differenzwinkel-Sollwertvorgabe hinterlegt sind, vorgenommen werden.

• Durch die Mehrmotoren-Antriebstechnik ist die Anzahl der Units innerhalb einer Bogen-Druckmaschine nicht begrenzt. Bei der Längswellentechnik nimmt mit zunehmender Unit-Anzahl die Grenzfrequenz stetig ab, so dass die maximal mögliche Maschinendrehzahl sinkt.
• Mit Hilfe der Mehrmotoren-Antriebstechnik lässt sich eine automatisierte Zahnspielausstellung bei beliebigen Betriebszuständen verwirklichen.
• Auf Grund der Weiterentwicklungen der Mehrmotoren-Antriebstechnik ergibt sich eine höhere Wirtschaftlichkeit gegenüber der momentan eingesetzten Längswellentechnik.

This results in the following advantages over the prior art:

• The use of longitudinal shafts in the drive train of a printing press only a fixed, unchangeable stiffening is achieved by a fixed differential angle. In contrast, the differential angle control offers the possibility variable, adapted to the print rigidity mimic. These changes can be made during the printing operation by appropriate algorithms, which are stored in the differential angle setpoint specification.

• Due to the multi-motor drive technology, the number of units within a sheet-fed press is not limited. In longitudinal shaft technology, the limit frequency decreases steadily as the number of units increases, so that the maximum possible engine speed drops.
• With the help of multi-motor drive technology, an automated gear play exhibition can be realized in any operating conditions.
• Due to the further developments of multi-motor drive technology results in a higher efficiency compared to the currently used longitudinal shaft technology.

These speed control loops are supplied with identical speed basic setpoints. With the exception of a master drive, each follower drive receives another setpoint, the additional speed setpoint, which is formed by a differential angle controller assigned to the follower drive.

The invention allows numerous embodiments. One of them will be explained in more detail with reference to the figures shown in the drawing.

Figur 1:

erfindungsgemäße Vorrichtung

Figur 2:

Impulsverlauf pro Zahnradumdrehung

It shows:

FIG. 1:

inventive device

FIG. 2:

Pulse progression per gear revolution

FIG. 1 shows a printing press 1, which consists of a feeder 2, a plurality formed as printing units subunits 3 to 6 and a boom 7. The drive of the printing machine 1 from the feeder 2 via the printing units 3 to 6 to the boom 7 via a closed gear train 8, which is formed by interlocking gears 8a to 8h. About this mechanical gear 8 are not described in the individual printing units 3 to 6 blanket cylinder, which interact with counter-pressure cylinders and the counter-pressure cylinders downstream transfer drums coupled. The way of the printing material in the in the FIG. 1 configuration shown in the direction of the arrow from right to left.

Two positionally adjustable individual drives 9 and 10 engage in two places of the gear train 8. Each position-adjustable single drive 9 and 10 is designed as an electric motor, wherein the single drive 9, the sub-units 3 and 4 and the single drive 10, the sub-units 5 and 6 and the boom 7 drives.

A pulser 11 is opposite the shaft 17 of the gear 8d and another pulser 12 is disposed opposite to the shaft 16 of the gear 8c. Each shaft 16 and 17 has a projection 18 and 19, respectively.

Both pulse generators 11, 12 are designed so that they each output an electrical pulse per gear revolution in each case a precisely defined angular position of the two gears 8c, 8d when passing the projection 18 and 19, respectively. In FIG. 2 the upper diagram shows the pulse progression on Pulse generator 11 and the lower part of the pulse waveform on the pulse generator 12, as it is detected by a connected to the pulse generators 11 and 12 control unit 13.

In addition, the control unit 13 is directly connected to the individual drives 9 and 10 and acts via an actuator 14 and 15 on the individual drives 9 and 10 a.

During operation of the printing press, the control unit 13 accesses the individual drives 9 and 10 and forces a rotation angle synchronous running of the drive elements 9 and 10 at the input points. In this case, the control unit 13 determines the actual position of each individual drive 9, 10 and compares these with setpoints stored in the control unit. Based on this comparison, each individual drive 9, 10 is controlled by the control unit 13 individually via the actuator 14, 15. The single drive 9 is thereby rotated by the angle φ 1 and the single drive 10 by the angle φ2.

By a setpoint specification determined according to the invention, the individual drives 9 and 10 are to be controlled such that in addition a predetermined constant rotation Δφ of the gear train between the input points of the individual drives 9, 10 is ensured. Indicator of the presence of such a rotation Δφ is that the tooth flanks of two adjacently arranged intermeshing gears on the meshing a touch under operating conditions straight and possibly still transmit a small load.

The time interval .DELTA.t of the pulses measured at the pulse generators 11, 12 resulting from the pulse progressions and its time changes is measured by the control unit 13 and converted into a proportional rotational angle difference at a constant engine speed.

For the correct determination of the rotational angle difference Δφ between the input points of the individual drives 9, 10 are switched off at the control of the Single drives 9, 10 evaluated by the pulse generators 11, 12 delivered pulses.

For this purpose, the printing machine 1 is first brought to generate certain load conditions in a predetermined operating condition in which the colors provided in the printing units and the printing units are turned on. In addition, a machine speed is set. Subsequently, a lag with respect to the individual drive 10 is generated at the individual drive 9 by the control unit 13 and increased until the time difference .DELTA.t1 between the pulses generated by the pulse generators 11 and 12 remains constant. The constant time difference Δt1 is stored in the control unit 13.

Thereafter, the control unit 13 controls the single drive 9 in the opposite direction, so that adjusts an advance on the input drive of the individual drive 9 relative to the drive of the single drive 10. This lag is also increased until the time difference between the pulses emitted by the pulse generators 11, 12 is constant. The thus determined constant time difference Δ t2 is stored in the memory of the control unit 13. In addition, the position of the electric motor is determined after setting the overfeed and used to determine the rotational angle difference Δφ2 analogous to the lead.

The control unit 13 then subtracts the time difference Δt2 and calculates therefrom an angular difference Δφ2, to which the angular difference Δφ2 is added.

The thus determined angular difference Δφ is used as the setpoint under production conditions of the regulation of the individual drive 9 by the control unit 13. This ensures a light contact system of the tooth flanks in a given direction of movement of the gear train 8 always.

In addition to the empirically determined overfeed, a further overfeed Δφ3 for the input drive of the individual drive 9 is generated by the control unit 13. This lead Δφ 3 is determined by the desired operating load of Printing machine in meshing and the gear train rigidity. Advantageously, the lead Δφ 3 can be seen in a map stored in the control unit 13. This lead Δφ 3 is added to the lead Δφ and taken into account in the control of the individual drive 9 as a setpoint.

The inventive method is applicable to various embodiments of the printing press. Thus, the number and design of subunits 3 to 6 is variable and may vary from press to press.

In order to determine a setpoint input, that is to say the rotation Δφ between the input points of the individual drives 9, 10, it is also possible to vary the drive torque of the first and second individual drives 9, 10 or to determine the setpoint values for the position control at a specific ratio the torques to be introduced by the individual drives are determined in the gear train resulting rotation Δφ. During test runs of the machine, the snapshot of the individual drives is measured by special sensors or determined indirectly via the current values of the drive motors.

For this purpose, the drive torque fed into the gear train 8a-8h via the first drive 9 is preferably increased, so that the torque to be fed in via the second drive 10 becomes smaller in order to maintain a predetermined speed. The torques fed in via the first and second motors 9, 10 are compared with one another and used to determine a desired value for the position control of the two individual drives, that is to say for the rotation Δφ of the gear train 8a-8h. Thus, an angle value Δφ can be determined which corresponds to a specific torque ratio. Further education can also be provided to perform the determination of angles of rotation Δφ at different speeds and / or different load situations.

In another embodiment of the invention for determining a desired value specification (determination of the angle of rotation Δφ), it is provided to first drive the machine via the first drive motor 9, so that guaranteed a flank system in the entire gear train is present. Then, when the motor 9 is switched off, the second drive motor 10 is actuated and the movements carried out by the gear train are detected by the position sensors (impulse or angle encoders) 11, 12. Thus, in particular, the angle to be executed by the second motor 10 can be determined until the loss caused by the reversal of the flank system in the gear train 8a-8h is brought out. The angle value determined in this way can then be used as the angle of rotation Δφ of the setpoint values for the position control of the individual drives 9, 10.

reference numeral

1

press

2

investor

3

printing unit

4

printing unit

5

printing unit

6

printing unit

7

boom

8th

gear train

8a-8h

gears

9

individual drive

10

individual drive

11

pulse

12

pulse

13

control unit

14

actuator

15

actuator

16

wave

17

wave

18

head Start

19

head Start

Claims (8)

1. A method for operating a printing machine (1), more preferably a sheet-fed offset printing machine, wherein two position-controllable individual drives (9, 10) operated independently of each other feed into a continuous wheel train (8), as a result of which part units (2, 7) of the printing machine (1) coupled to the wheel train (8) are driven and rotation of the wheel train (8) between input drive points of the individual drives (9, 10) is generated, wherein a rotary angle position of the wheel train (8) each is measured in two different positions, and wherein a position of at least one of the two individual drives (9; 10) is set as a function of a difference resulting from these rotary angle positions and as a function of a differential angle set value, characterized in that at least two sensors arranged in different positions of the wheel train (8) supply angle information as a function of variable operating states of the printing machine and with the help of a multiplicity of temporarily varied differential angle set values, basic set values for a differential angle control of individual drive axles are determined relative to each other.
2. The method according to Claim 1, characterized in that the rotary angle difference of the wheel train is determined before the start of the printing process as a function of a predetermined operating state of the printing machine (1) and at least the one individual drive (9; 10) is preloaded by this rotary angle difference during the printing process.
3. The method according to Claim 2, characterized in that following the setting of the predetermined operating state of the printing machine the wheel train is moved in a predetermined direction of rotation by at least one of the two individual drives (9; 10), wherein the difference of the rotary angle positions within the wheel train (8) is determined in that the wheel train (8) is moved until with multiple measurement a constant rotary angle difference of the wheel train (8) is determined.
4. The method according to Claim 3, characterized in that the position of the at least one position-controllable individual drive (9; 10) is determined before the movement of the wheel train (8) and after reaching of the constant rotary angle difference of the wheel train (8), wherein from the two positions a rotary angle difference of the at least one individual drive (9; 10) is determined and from the sum of the rotary angle difference of the wheel train (8) and the rotary angle difference of the at least one individual drive (9; 10) the preload is determined by which the at least one individual drive (9; 10) is preloaded during the printing process.
5. The method according to Claim 4, characterized in that during the printing process on the at least one individual drive (9; 10) a further rotary angle difference is set which is determined from a predetermined operating load and/or the wheel tensile stiffness.
6. The method according to Claim 1, characterized in that the rotational speed set values for the two individual drives (9, 10) are formed as sum from a rotational speed basic set value and rotational speed additional set values, wherein the latter are generated from the differential angle controllers.
7. The method according to Claim 1, characterized in that differential angle set values are generated as a function of movement quantities more preferably angular velocities or angular accelerations or force quantities, more preferably rotational moments or electrical quantities, more preferably drive currents and drive voltages as well as combinations of these quantities.
8. The method according to Claim 1, characterized in that determination of the actual values for the differential angle controllers is carried out between random not necessarily adjacent drive axles by means of differentiation of associated actual angle signals or by means of differentiation of the actual rotational speed signals with subsequent integration.

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