EP2147138A1

EP2147138A1 - Method and device for operating a drawing line or drawing unit

Info

Publication number: EP2147138A1
Application number: EP08734486A
Authority: EP
Inventors: Rolf Schröder; Michael Breidert
Original assignee: Fleissner GmbH
Current assignee: Truetzschler Nonwovens GmbH
Priority date: 2007-05-24
Filing date: 2008-04-15
Publication date: 2010-01-27
Anticipated expiration: 2028-04-15
Also published as: BRPI0812151B1; CN101668884B; BRPI0812151A8; EP2147138B1; BRPI0812151A2; JP2010529305A; PL2147138T3; ES2546085T3; WO2008141602A1; US9657414B2; US20140353866A1; US20100072650A1; JP5470244B2; CN101668884A

Abstract

The invention relates to a method and device for operating a drawing line or drawing unit for drawing cables from polymer threads using a plurality of driven drawing rollers. According to the invention, each drawing roller (2.1, 2.2) is controlled to a prescribed motion value. To this end, each drawing roller (2.1, 2.2) is associated with a separately controllable drive device (3.1, 3.2).

Description

Method and device for operating a drafting line or drafting system

The invention relates to a method and a device for operating a drafting line or a drafting system according to the preamble of the method or the device claim.

It is already a device for drawing of cables from high polymer, synthetic threads in drafting systems with inlet and drafting systems with distribution of the cable mass in several single strands known (DE 21 48 619).

The invention is based on the object, a method and a

To improve device for driving a drafting system according to the preamble of the method or device claim and to expand the capabilities.

The object is achieved by the features of the Verfahrensbzw. Device claim solved. Further developments of the invention will become apparent from the respective dependent claims.

According to the invention, provision is made in particular for the drive of each draw roll to take place via a separate drive device which can be controlled via an actuator to a designated rotational speed or a respectively required torque for driving the corresponding draw roll. As a result, by means of different speeds (rotational speeds) between two draw rolls, a desired stretching of the draw rolls or threads running around the draw rolls can be achieved. The cumulative speed ratio between the first inlet and the last outlet stretch roller is between 1: 3 and 1: 4. As the drive of the individual drafting rollers or godets not centrally via a drive device, but each godet is driven individually, the drafting can be operated differentiated. It is also advantageous that the drives within a drafting system are approximately equal and the load distribution can be made uniform. By the individual drive, the slip can be significantly reduced.

For this purpose, it is advantageous that the required torque of the drive device or the drives of the individual godets by means of a control / regulating device takes place.

It is also advantageous that the motors are designed as asynchronous drives and the control / regulating device has a frequency converter (inverter, frequency converter) together with the motor coupled to the speed sensor. About the frequency converter, the setting of the required speed and thus also on the torque on each of a galette. With the help of the frequency converter, the required optimum speed can be set for each individual motor. At higher

Control requirements find field oriented inverter use. These consist of a speed controller based on a lower-level current controller. In an engine model stored electronically in the inverter, the engine parameters are stored or, if necessary, automatically determined and adapted. This has the advantage that there does not have to be separate RPM measurement and feedback to control RPM and torque. The recirculated, used for control size is rather exclusively the instantaneous current. On the basis of its size and phase position to the voltage all required engine conditions (speed, slip, torque and even the thermal power loss) can be determined. If a disturbance occurs, for. As a demolition of the cable during the stretching, so this is also detected as a disturbance variable via a speed sensor and / or with the help of the frequency converter, generates an error message and the system can switch off automatically. For this purpose, the speed and / or the torque of each of the motors is detected and compared with predetermined values, which can only result in an accident (sudden increase in speed). These values are determined and stored. The targeted setting of the speeds allows the corresponding motors to be optimally dimensioned, the engine power fully deployed, and thus the costs reduced. Furthermore, the field of application of such a system expands, and the frequency of disturbances is also avoided.

Furthermore, it is advantageous that the frequency converter associated with the motor compares the actual torque with the desired torque and then makes an adjustment of the drive speed of the corresponding motor.

It is advantageous that the surface of these godets are chrome-plated or have a ceramic layer in order to produce a better static friction.

The following method is of particular advantage:

a) the first godet is driven at a predetermined speed which does not vary by the control, and the speed of the last godet and thus the draw ratio are determined;

b) the system is started according to the dotted line (FIG. 7) with a freely selectable start stretch, wherein the Speed increase is distributed linearly or freely selectable over the individual godets,

c) the cable is placed on the godets and the torque optimization is started,

d) the drive of the individual godets is continuously monitored by means of a frequency converter and the actual torque compared with the calculated mean target torque, then the corresponding speed is controlled while the system is raised to the terminal speed,

e) the speeds are stored in a setpoint curve and can be used to accelerate the startup process at the next startup.

Furthermore, it is advantageous that an optimal drive setting of all the motors or the setting of the desired drive torque of each motor is carried out automatically by means of a stepwise approach or iteration to a desired torque curve or desired torque curve.

Further advantages and details of the invention are explained in the patent claims and in the description and illustrated in the figures.

Show it:

1 is a schematic representation of a drafting line with two drafting, 2 is a plan view of the drafting line with two drafting units, each with a collective drive,

3 is a schematic representation of an arrangement of individual motors for individual and direct drive of the godets of a drafting system in plan view,

4 shows a diagram of the process speed of the godets of a drawing line with two drafting devices according to FIG. 2, FIG.

Fig. 5 is a diagram of the torque absorption of the individual

Godets of the drawing line according to FIG. 2,

Fig. 6 is a diagram of the torque absorption of the individual godets of a drafting line with two drafting according to

2 with a second speed or stretching profile,

Fig. 7 is a diagram with the torque at an equalized torque increasing speed

Galette arrangement according to FIG. 3,

8 is a diagram of the torques of the individual godets according to FIG. 3 with the machine in the closed position.

In Fig. 1 shows the principle of the structure of a known drafting line 1 with draw rolls or godets 2, which are arranged in two drafting units 1.1, 1.2. In the two drafting units 1.1 and 1.2 each seven godets 2 are arranged. As shown in Figure 2, in a drafting line 1 according to the prior art, the godets 2 of the drafting systems 1.1, 1.2 via a central drive device or via an associated engine 3.1, 3.2 and a symbolically represented gear in the respective frame 4.1, 4.2 driven.

In Fig. 3, the drafting line 1 according to the invention with a total of fourteen godets 2 is shown. The drafting line 1 according to this embodiment consists of a first drafting system 1.1 and a second drafting system 1.2.

According to FIG. 3, individual motors 31.1, 31.2,... 32.14 are accommodated in the drafting devices 1.1, 1.2, each in a holder 5.1, 5.2, which also rotatably support the godets 2. The brackets 5.1, 5.2 are shown only schematically. 2, the overall arrangement of the drafting line 1 is shown as FIG. 1, so that the assignment of the drives 31.1, 31.2,... 32.14 to the fourteen godets of the two drafting systems 1.1, 1.2 reveals.

Each motor 31.1, 31.2 ... 32.14, which is preferably designed as a water-cooled motor, is used for direct drive of a single Galette 2. Between the drive shaft of the motor 3 and the drive shaft of the godet 2, a joint, a propeller shaft or a self-aligning bearing is provided , whereby lateral offset or caused by bending moments effects are compensated.

4 shows a speed diagram with two different speeds V of a first and second drafting system 1.1 and 1.2 driven by a respective engine 3.1 and 3.2, where Vi is the speed (peripheral speed = speed of the godet x radius godet surface, the peripheral speed corresponds to the speed of the cable 6 Further, in this description, speed is always referred to, with the value for the speed of the godets resulting from said relationship) of the godets 2 of the first drafting system 1.1 and V _{2 represents} the speed of the godet 2 of the second drafting system 1.2 (see FIG. 1 and FIG. 2). The solid line shows a higher, the dashed line a lower draw ratio. The course of the applied by the cable 6 on the godets 2 torques M (starting from an average torque) is shown in the diagrams of FIGS. 5 and 6. The bars in solid lines according to FIG. 5 correspond to a higher and the bars shown in dashed lines in FIG. 6 to a lower draw ratio - see the velocities shown in solid or dashed lines in FIG.

FIG. 4 illustrates that the first drafting device 1.1 is driven more slowly than the second drafting device 1.2, so that the cables 6 shown schematically in FIG. 1 are stretched. As a result, the torque absorption of the second drafting system 1.2 in the

Total higher than the torque capacity of the first drafting system 1.1. The difference in the torques of the first and second drafting systems 1.1 and 1.2 represents the friction heat or the stretching force required to stretch the cable or the filaments 6. The stretching of the molecules of a filament requires a certain amount

Stretching force. By stretching the molecule of a filament, a certain friction between the individual molecules is generated, so that the filaments or the cable can be heated to about 100 ⁰ C.

5 shows the distribution of the torques M of the fourteen godets 2 in the two drafting units 1.1, 1.2 (see FIG. 4-solid line). FIG. 6 shows the torque distribution at a smaller draft (FIG. 4 - dashed line). The maximum and minimum torque values are marked with M-tmax, M2max, M2min etc. As indicated in Fig. 1, the last drive roller of the last godet 2 of the first drafting system 1.1 and the first drive roller of the first godet 2 of the second drafting system 1.2 is wrapped by the cable 6 only 90 °, so that there is no full torque transmission at this point , This also implies that at this point an increased slip occurs. Since the cable 6 can slip over the surface of the godet 2 at these points, this godet wears more heavily and does not transmit the full torque. The tensile forces on the last godet 2 of the first drafting system 1.1 and on the first godet 2 of the second drafting system 1.2 are therefore usually somewhat lower than at the adjacent godets 2, therefore usually slightly lower than at the adjacent godets 2. For this purpose, it is advantageous that Producing a better stiction the surface of these godets is chromed or has a ceramic layer.

When calculating the driving force according to the example according to FIGS. 1 and 2 (prior art), the selection of the drive motor is determined by the maximum torque Ivbmax (FIG. 5 or FIG. h., The drive device is oversized. As a result, larger gears are required, so that known systems according to FIG. 1 are complicated and expensive.

In a drive device according to FIG. 3, the energy consumption can be reduced. Here, the drives are designed individually for each maximum need of the associated godets 2, by the

Drive speeds are individually graded and thus for each godet 2 a predeterminable or ideal drive torque is provided. For this purpose, a total of a torque M _d = M / N must be provided. Here, M _d is the average torque, M is the torque of a motor and N is the number of drives for driving a single godet 2. The individual motors 31.1-32.14 are designed for the respective maximum torque of a godet 2. With the aid of a frequency converter, the necessary speeds Vi and V _{2 can be} monitored and adjusted in order to achieve the desired extension of the cable 6. For this purpose, a torque control is used to drive all the motors 31.1-32.14. The previously determined Md is the target torque for the drive of all motors, compare FIGS. 7 and 8.

Vi is the initial speed, which is gradually increased according to the desired extension of the cable 6 to the subsequent values shown in FIG. 7 in order to achieve the desired extension. If the actual torque deviates from the setpoint torque, the current speed is iteratively adjusted to the setpoint speed using the control.

As is apparent from Fig. 7, the cable 6 can be forgiven slightly at the beginning, since it can still be stretched very much. The more the cable 6 has been stretched, the higher the torque required to drive the corresponding motor 3, since the stretching forces increase as the elongation increases. The speed gradations are much larger in the godets one to seven than the speed gradations in the following godets.

The torques of the godets 2 are scanned several times per unit time, in order to adjust the drive speed for the individual godets 2 in this way. The signal sampled by the control represents the control variable for determining the required drive speed and thus for determining the required torque of the godets 2. Due to the continuous torque monitoring and adjustment of the required torque, the drive system is continuously optimally adjusted to the required conditions after a short break-in period. As a result, only as much drive energy is provided as is necessary to drive each individual motor 3. An oversizing of the drive device can be avoided by the control according to the invention with the aid of the control cam according to FIG. 7.

The drive of a drafting line in the optimization phase takes place according to the following process steps:

a) the first godet 2 (Figure 7 - N = 1) is driven at a predetermined speed V ₁ (which does not change by the control, ie remains constant and according to a

Speed value is selected, with the example coming from the spinning cable 6 is supplied). Also specified is the speed V _{2 to be} traveled during operation of the last godet (as shown in FIG. 3 - driven by motor 32.14). This determines the draw ratio. This value also depends on how the drawn cable 6 is to be further processed.

b) the system is started according to the dotted line (FIG. 7) with a freely selectable start stretch, wherein the speed increase is distributed linearly (or freely selectable) over the individual godets. This means that the godets following the first godet (Figure 7 - far left, N = 1) (Figure 7 - N = 2, 3, 4 ...) have a linear (or arbitrary) function be driven increasing speed. Thus, an initial speed distribution is specified, which is marked with K _A in FIG. The speed of the last godet (FIG. 7-N = 14) is preferably smaller than that provided Final velocity V ₂ . In FIG. 7, VA is the velocity value of the start stretch, in this case VA <VE.

c) the cable 6 is placed on the godets and the torque optimization started

d) the drives 31.1, 31.2 ... 32.14 of the individual godets 2 are continuously monitored by means of the control and the actual torques are compared with the predetermined target torques. Accordingly, the speeds of the individual godets are regulated. Starting from an initial velocity distribution (FIG. 7 - curve KA), the drives 31.2... 32.14 of the godets are started up - during the individual iterations, the speed distributions indicated by the dashed lines in FIG. 7 result above the start curve K _A. This optimization takes place until the torques of the individual drives 31.1, 31.2... 32.14 correspond to the predefined setpoint values and the speed value of the last godet (FIG. 7-N = 14) the predefined final speed value V ₂ which defines the draw ratio. reached. The

Torques of the individual drives 31.1, 31.2... 32.14 are preferably regulated until the situation shown in FIG. 8 results, ie the same torque prevails everywhere.

e) the velocities of the godets of the end curve K _E thus obtained are stored and can be used as default values in the next starting process for accelerating the starting process.

As previously mentioned, it is possible to drive the last godet (N = 14) equal to the draw ratio defining speed V2 (the corresponding speed) (V _A = V _E ). Preferably but a starting value according to the relationship V _A <V _E chosen so that adverse situations during the optimization phase can be avoided in any case.

Speed changes (Vi u / o V ₂ ) during operation of the drafting line according to the invention are carried out in an analogous manner. Here, too, an optimization of the speeds of the individual godets is such that predetermined solenoids are achieved.

LIST OF REFERENCE NUMBERS

1 drafting line

1.1 first drafting system

1.2 second drafting system 2 drafting roller, galette

3.1 Drive device, engine (first drafting system 1.1) 3.2 Drive device, engine (second drafting system 1.2)

31.1 Engine first godet drafting system 1.1

32.1 Engine first godet drafting system 1.2

4.1 frame / gearbox

4.2, frame / grate 5.1 Bracket / frame

5.2 Bracket / frame

6 filament, cable

7 Feeding device or nozzle of the spinning system Vi Speed (galette N = 1) V _A Starting speed (galette N = 14)

VE final speed

N = 1 first godet according to FIGS. 3, 4, 7

N = 14 last godet according to FIGS. 3, 4, 7

K _A Speed curve at start - start of optimization

K _E Curve progression at final speed - optimization achieved

Claims

claims:

1. A method for operating a drafting line or a drafting system for drawing of cables from polymeric threads using a plurality of driven draw rolls, characterized in that each draw roll (2.1, 2.2) is controlled individually to a predetermined movement value.

2. The method according to claim 1, characterized in that each draw roll (2.1, 2.2) is controlled to a predetermined speed value.

3. The method according to claim 1, characterized in that an influencing of the driving of the motors (3.1, 3.2) on the drafting rollers (2.1, 2.2) applied torque takes place.

4. The method of claim 1, 2 or 3, characterized in that a speed control is carried out with subordinate current control.

5. The method of claim 1, 2 or 3, characterized in that the actual torque of a motor (3.1, 3.2) detected, compared with a predetermined target value and corresponding to a control of the motor (3.1, 3.2).

6. The method according to any one of the preceding claims, characterized in that the rotational speed and / or torque of each of the motors (3.1, 3.2) detected and compared with predetermined values and exceeding the values is assessed as an accident.

7. The method according to claim 6, characterized in that in case of malfunction stopping the motors

(3.1, 3.2).

8. The method according to any one of the preceding claims, characterized by:

a) a first godet (2) is assigned a predetermined

Speed (Vi) driven, also the speed of the last godet and thus the draw ratio is set,

b) the system is started with a freely selectable start stretch, wherein the speed increase is distributed linearly or freely selectable over the individual godets,

c) the cable (6) is placed on the godets and the torque optimization is started,

d) the drive of the individual godets (2) is continuously monitored and the actual torques compared with the calculated mean desired torques, then the corresponding speed is regulated, while the plant on the

Top speed (V2) is raised,

e) the speeds are recorded, stored in a setpoint curve and are used to accelerate the startup process at the next startup.

9. The method according to any one of the preceding claims, characterized in that an optimal drive setting of all engines (3.1, 3.2) or the setting of the desired drive torque of the motors (3.1, 3.2) by means of a gradual approach or iteration to a target torque Curve done.

10. An apparatus for driving a drafting line or a drafting system for drawing of cables from polymeric threads by means of several drivable draw rolls, for carrying out the method according to claim 1, characterized in that each draw roll (2.1, 2.2) a separately controllable drive device (3.1 , 3.2) is assigned.

11. The device according to claim 8, characterized in that each draw roller (2.1, 2.2) is associated with a speed.

12. The device according to claim 1 or 2, characterized in that the drive devices (3.1, 3.2) are designed as asynchronous motors with associated Frequenzumrichtren.