EP2502860B1 - Device for winding a web of material - Google Patents

Description

The invention relates to a device for winding a web of material to a winding roll with at least one roller on which the winding roller bears during winding and which rotates during winding, wherein the roller is mounted in a bearing device with a bearing at each end of the roll.

The invention will be described below with reference to a paper web as an example of a material web. But it is also applicable to other webs where similar problems occur. Devices for winding paper webs reach high working widths of more than 10 m. The winding rolls produced on them can achieve a final diameter of 1.6 m and more in the case of longitudinally divided webs. In the case of undivided beans, the final diameters may be 3.5 m and more.

When winding paper webs you can often observe that the winding device gets into vibration. These vibrations are undesirable for several reasons. On the one hand, they produce noises. On the other hand, they worsen the quality of the produced roll. In critical situations, the vibrations can be so strong that they lead to the ejection of the roll from the winding device.

Especially when winding up papers with a high coefficient of friction, there are strong unwanted oscillatory phenomena. These papers are generally referred to as vibration-critical papers. These are present when the static friction coefficient of the paper layers is greater than 0.5, in particular reaches the value 0.7 and more.

It is believed that the vibrations are due to a self-excitation effect from the winding roll. Due to a high Haftreibbeiwert the Papierlageh with each other, the usual position shifts during winding of the paper web are largely suppressed. This has the consequence that dynamically induced winding hardness differences on the circumference of the winding roll set, which lead to changes in radius on the circumference of the winding roll, because the winding hardness differences are not sufficiently compensated by the lack of positional shift. From any dynamic deformation of the winding roll or the dynamic winding load on the one or more rollers remains a small proportion as permanent stationary deformation, which then acts as a Wegerregung when re-entering a winding contact zone. This regenerative effect leads to the coincidence of some harmonics of the winding speed with certain natural frequencies of the winding system formed by the rollers and the winding roll to a self-excitation process in which amplify the vibrations themselves.

Attempts have been made so far to counteract this problem by setting the first natural frequency, ie the lowest natural frequency, of the system so high that it is not reached when operating the winding device. The known systems were thus designed for the highest speed of the roller or rollers. It is considered that only rotational frequencies below the highest speed when starting the winding device are traversed. The effective from a winding roll on the winding rollers exciting frequency is greatest when the winding roll has been accelerated to the maximum winding speed and with respect to the occurred then main winding phase still has the smallest diameter. With increasing diameter of the winding rolls and with constant supply of the material web then decreases the rotational frequency of the winding roll and thus exerted by her on the winding rollers excitation frequency again accordingly.

In addition, one has, as for example in the EP 1 726 547 A1 discloses attempts to reduce the leakage of vibrations by suitable dampers in the form of hydraulic cylinders.

The invention has for its object to be able to wind even vibration-critical material webs with as little problems.

This object is achieved in a device of the type mentioned above in that the bearing is a hydrostatic Support with at least a first bearing pocket, which is fed with hydraulic fluid.

In a hydrostatic support, the roller rests on hydraulic fluid, which flows continuously through an "oil gap", which results at the boundary of the bearing pocket. Regardless of the load, the same oil gap always appears on average at the boundary of the bearing pocket. However, short-term or fast movements, such as those of a swinging movement, can be recorded. An example electronic control of the roller position is not required.

Preferably, the bearing pocket is fed with a constant volume flow of hydraulic fluid. As the load increases, the oil gap decreases slightly and the throttle resistance for the hydraulic fluid flowing through the oil gap increases. This increases the pressure in the bearing pocket, which counteracts the increased load. This results in a static position control, so to speak. A constant volume flow can be provided relatively easily, for example by a constant-flow pump or a pump with a constant-flow regulator.

Alternatively, the storage bag can be connected via a throttle with a constant form. The constant admission pressure depends on the expected load and should be much greater than a counterpressure generated by this load. Also in this case results in an automatic static position control. When the load increases, the throttle resistance increases in the Oil gap. Accordingly, less hydraulic fluid can flow out of the bearing pocket and the pressure drop across the throttle between the constant admission pressure and the bearing pocket becomes correspondingly smaller, so that the pressure in the bearing pocket rises again. This increasing pressure acts to escape the increased load.

Both options make use of the fact that the pressure in the storage bag automatically adapts to the load conditions. This adaptation can be done very quickly, so that the vibrations occurring during winding can also be well absorbed. On average, the roller remains in the desired position. But the bearings can absorb the vibration well.

Preferably, the bearing pocket is connected via a throttle with a pressure accumulator in connection. The pressure accumulator takes during a vibrational movement of the roller for a short time, the liquid that can not flow through the gap at the edge of the bearing pocket, and returns it in the opposite movement of the roller off the liquid in each case must flow through the throttle, causing a damping , With the help of the throttle so energy is taken out of the oscillating system. The combination of hydrostatic support and pressure accumulator with throttle thus causes a clear separation of the dynamic and the static properties of the bearing, so that can be achieved in a simple manner different stiffnesses for the static state and for the dynamic state.

Preferably, the throttle has an adjustable throttle resistance. This allows you to adjust the damping. It is easy to influence the dynamic stiffness of the bearing, so that the dynamic stiffness can be adjusted so that as few oscillations as possible are forgiven.

Preferably, the throttle is connected to an externally operable actuator Accordingly, one can change the dynamic stiffness even when the throttle is installed inside the bearing. This makes it possible to effect adaptive damping, i. You can adjust the dynamic stiffness and damping depending on the situation.

Preferably, the hydrostatic support is connected in series with a spring arrangement. The spring arrangement can for example produce a bias in the direction of the bearing pocket. It can also be used to make the bearing harder overall.

Preferably, at least one further hydrostatic support is provided with at least one second bearing pocket, which is supplied with a constant volume flow of Hydraülikflüssigkeit or via a throttle of a constant pressure, wherein the second bearing pocket has a different effective direction than the first bearing pocket. For example, it is possible to align the direction of action of the first bearing pocket and the direction of action of the second bearing pocket at an angle of 90 ° to one another. This makes it possible to support the bearing in two or more directions. So you are not on it anymore limited to hydrostatically support the bearing only in the direction of gravity.

Preferably, at least one storage pocket is divided into two sub-pockets, each of which is fed via a supply throttle. With this configuration, one can prevent tilting of the bearing relative to the bearing pockets. Rather, it is ensured that the bearing is always held over its entire support surface parallel to the edges of the bearing pocket.

Preferably, the bearing device has a stiffness that varies with the exciter frequency. So you have a static stiffness that is effective against loads whose frequencies theoretically go to zero. In practice, loads are usually considered static, whose frequencies are less than 0.1 Hz. In contrast, the dynamic stiffness is effective against loads whose frequencies are higher than 0.1 Hz. Thus, when a roller rotates, the static stiffness remains substantially effective against the effective weight of the roller, while the dynamic stiffness must be effective against the higher frequency loads then occurring. The stiffness here is the sum stiffness of both bearings of a roll.

It is preferred that the bearing device has a static stiffness which is greater than the rigidity of the roller. The storage facility is therefore for very small exciter frequencies. (f <0.1 Hz) relatively stiff, so that even when larger forces, such as the weight of a finished winding roll, no change in location of the roll is observed.

It is preferred that the static stiffness is at least 2 times the rigidity of the roll. The static stiffness can therefore be chosen relatively large.

It is also preferred that the bearing device at the reduced rotational frequency has a dynamic stiffness which is smaller than the rigidity of the roller. With increasing excitation frequency, the rigidity of the bearing device is thus reset, so that the Lagereinrichtüng the vibration movement of the roller presents less resistance. In the range of the vibration amplitude, the bearing device can thus yield within certain limits. The roller is always in the winding process by several influences, so superimposed excited. The arousal changes continuously, as it mainly emanates from the winding roll. The actual out of the current rotational frequency of the roller itself excitation is far better predictable in many areas and therefore plays a sideline role in achieving critical winding conditions.

It is preferred that the dynamic stiffness is at most 50% of the rigidity of the roller. Thus, there is a significant difference between the dynamic stiffness and the static stiffness of the bearing device.

In any case, with this configuration, when the maximum winding speed has been reached, the device can be moved overcritically, i. the rotational frequency of the roller may be greater than the natural frequencies of the system of roller and bearing device. This makes it possible to produce a phase shift of approximately 180 ° between the path excitation of the (non-round) winding roll and the system response of the oscillating roll with the winding roll resting thereon. Even if this phase shift is not completely achieved, there is nevertheless a very positive effect in that the vibrations are damped or are not excited as much as before. Of course, the device can also be driven under critical.

If the winding roller rotates when reaching its maximum diameter with a reduced rotational frequency, the first natural frequency may even be smaller than the reduced rotational frequency of the winding roll. As stated above, the web is wound many times at a constant speed. This causes the speed of the winding roll decreases with increasing diameter of the winding roll. The natural frequency of the system of roller and bearing device is then chosen even smaller, namely smaller than the reduced rotational frequency of the winding roll at its maximum diameter. The maximum diameter is usually predetermined by the winding direction. The same applies to the desired feed speed of the material web and thus for the maximum rotational frequency of the roller, which it reaches when at the beginning of a winding process, the material web on the desired feed rate has been accelerated.

Fig. 1

eine schematische Darstellung einer Vorrichtung zum Aufwickeln einer Materialbahn zu einer Wickelrolle,

Fig. 2

eine erste Ausführüngsförm eines Lagers,

Fig. 3

eine zweite Ausführungsform eines Lagers,

Fig. 4

eine dritte Ausführungsform eines Lagers,

Fig. 5

eine vierte Ausführungsform eines Lagers und

Fig. 6

verschiedene Frequenzverläufe.

The invention will be described below with reference to preferred embodiments in conjunction with the drawing. Herein show:

Fig. 1

a schematic representation of an apparatus for winding a web to a winding roll,

Fig. 2

a first embodiment of a bearing,

Fig. 3

a second embodiment of a bearing,

Fig. 4

a third embodiment of a warehouse,

Fig. 5

a fourth embodiment of a bearing and

Fig. 6

different frequency characteristics.

Fig. 1 shows very schematically a winding device 1 in the form of a Doppeltragwalzenwicklers. The winding device 1 has two support rollers 2, 3, which form between them a Mickelbett 4, in which a schematically illustrated winding roller 5 is located, on which a material web, not shown, is wound up. The formation of such a Doppeltragwalzenwicklers itself is known.

The two support rollers 2, 3 are mounted in a machine frame 6. For this purpose, each support roller 2, 3 has a bearing device with a bearing 7, 8 at each end of the support rollers 2, 3. Only one camp 7, 8 is in Fig. 1 each visible.

Such a winding device can be operated at a maximum feed rate. This feed rate is, for example, 2,500 m / min or 3,000 m / min. This results in a certain speed and thus a certain rotational frequency of the support rollers 2, 3. For this rotational frequency, the winding device is designed. The speed of the winding roller 5 is at the beginning of a winding process largest, because the winding roller 5 here has its smallest diameter. At the end of the winding process, when the winding roller 5 has reached its maximum diameter, the winding roller 5 rotates at a reduced rotational frequency.

Each support rollers 2, 3 has (including its storage device with the bearings 7 and 8) to a first natural frequency. The first natural frequency is the lowest natural frequency. In simple terms, this is a natural bending frequency. The first natural frequency of the carrier roll 2, 3 with bearings 7, 8 is now selected so that it is smaller than the maximum rotational frequency of the carrier roll 2, 3.

This causes the device 1 to operate supercritically. can be with the result that it is possible to generate a phase shift of approximately 180 ° between the excitation path of the winding roll 5 and the system response: the vibration system from a support roller with the superimposed deformable winding roller 5.

In order to achieve this state, the support rollers 2, 3 must be dynamically tuned very soft. However, the system must be relatively hard statically, for example, to accommodate the mass of the finished winding roll 5 can.

One way to achieve this goal is in Fig. 2 shown. Fig. 2 shows the bearing 7 enlarged and in a highly schematic form.

The bearing 7 has a bearing housing 9, in which a roll neck 10 of the support roller 2 is rotatably mounted. The roll neck 10 may well be stored in the bearing housing 9 with rolling bearings or the like.

The bearing housing 9 is arranged in a machine housing 11, which is connected to the machine frame 6 or forms part of the machine frame 6. The machine housing 11 has a first bearing pocket 12 of a hydrostatic support in the direction of gravity below the bearing housing 9. The first bearing pocket 12 is connected to a feed channel 13 for hydraulic fluid. The supply channel 13 is supplied via a supply device not shown with a constant current Vp to hydraulic fluid. The necessary pump and control device is known and therefore not shown.

The first bearing pocket 12 is surrounded by a ring-like oil web 14. The oil bar 14 forms with the bearing housing 9 a gap 15 which is also formed circumferentially around the bearing pocket 12. The on the supply line 13th incoming hydraulic fluid can therefore only escape via the gap 15 and be discharged via a drain 16.

Due to the fact that the volume flow Vp of the hydraulic fluid is constant, in the static case there is always an approximately constant average height ho of the gap 15 so that the bearing housing 9 always has a clearly defined position relative to the machine housing 11, without any kind of whatsoever other regulation would be required.

As an alternative to a constant volume flow, it is also possible to provide another type of supply of the bearing pocket 12 with hydraulic fluid: the bearing pocket 12 is fed with a higher pressure and the hydraulic fluid is supplied via a throttle (not shown). Also in this case, the described effect results.

The first storage bag 12 is connected to a pressure accumulator 17 in connection and via a throttle 18. The pressure accumulator 17 is here as. Gas pressure accumulator formed with a membrane 19 which separates a liquid portion 20 from a pressurized gas portion 21.

Now, if the support roller 2 vibrates, and the bearing housing 9 is replaced in corresponding vibrations. As a result, while the gap 15 is maintained on average with its height ho. However, the thickness of the gap 15 varies with the same frequency with which the support roller 7 oscillates.

Since the constant volume flow Vp of the hydraulic fluid is supplied via the supply channel 13, in the time in which the gap 15 has been reduced and thus the flow resistance has been increased, the hydraulic fluid then not flowing out through the gap 15 can be in the fluid region 20 of the pressure accumulator 17 be recorded. In the times in which the gap 15 has increased slightly, the liquid is then discharged from the pressure accumulator 17 again.

Both when flowing into the pressure accumulator 17 and when flowing out of the pressure accumulator 17, the Hydraülikflüssigkeit must flow through the throttle 18. Then kinetic energy is converted into heat energy. The oscillating system is thereby deprived of energy.

In this way results in a relatively soft storage against vibrations. In other words, the bearing 7 has a high rigidity against static loads and a relatively low rigidity against dynamic loads. Based on the rigidity of the support roller 2, the static stiffness of the bearing 7, for example, at least twice as large and the dynamic stiffness of the bearing 7 is, for example, at most half as large.

Since the bearing housing 9 relative to the machine housing 11 in principle immovable, a striking of the bearing housing 9 on the machine housing 11 under extreme loads under the expected Quetschöldämpfung on the oil web 14 of the hydrostatic bearing is completely uncritical.

The throttle 18 may have a variable throttle resistance. This is schematically represented by an arrow 22. You can use an externally operable adjusting device for adjusting the throttle resistance, such as an electric motor or the like. Accordingly, it is possible to adjust the throttle resistance of the throttle 18 even when the throttle 18, as shown, installed in the bearing 7 and thus is not accessible.

The bearing housing 9 has a cross section in the form of a rectangle in the present embodiment. The first bearing pocket 12 acts on one side of this rectangle. Further, two second bearing pockets 23, 24 are provided, which act on sides of the rectangle, which are arranged perpendicular to the side on which the first bearing pocket 12 acts. Also, the second bearing pockets 23, 24 are connected to feed channels 25, 26, which with a constant volume flow. Vp be supplied. The second bearing pockets 23, 24 are surrounded by oil lands 27, 28, which form an oil gap 29, 30 with the bearing housing 9, so that the bearing housing 9 relative to the machine housing 11 in other directions has a hydrostatic support. These second bearing pockets 23, 24 can then also be connected to a pressure accumulator, not shown.

Fig. 3 shows a modified embodiment of the bearing 7, in which the same and functionally identical elements are provided with the same reference numerals.

In this embodiment, the second bearing pockets 23, 24 are omitted. Instead, the bearing housing 9 is supported here relative to the machine housing 11 by spring assemblies 31, 32. These spring assemblies 31, 32 are relatively soft parallel to the effective direction of the first bearing pocket 12, but perpendicular to it relatively hard. The effect of the spring assemblies 31, 32 is therefore added to the effect of the pressure of the hydraulic fluid in the first bearing pocket 12, so that the hydraulic support formed by means of the bearing pocket 12 and the spring assembly formed by the spring packs 31, 32 are connected in series. The spring assemblies 31, 32 may be formed for example by bending spring packages. This combination can be useful if due to the boundary conditions, such as space, limited oil flow, storage volume, etc., the hydrostatic bearing in conjunction with the pressure accumulator does not provide the desired combination of dynamic stiffness and damping behavior.

Fig. 4 shows a further embodiment of the bearing 7, which is essentially the of Fig. 2 equivalent. The same and corresponding components are therefore provided with the same reference numerals.

Here again two second bearing pockets 23, 24 are provided, which has the advantage that one can realize an isotropically damping bearing unit which ensures optimal damping properties for all diameters of the winding roller 5 and thus for all load angles in the winding bed 4.

In addition to the embodiment according to Fig. 2 a compression spring 33 acts on the bearing housing 9. The compression spring 33 is biased by a lid 34 connected to the machine housing 11, so that the bearing housing 9 is biased in the direction of the first bearing pocket 12.

Fig. 5 shows a further embodiment of the bearing 7, wherein the same and functionally identical elements are denoted by the same reference numerals as in the previous embodiments.

The (relative to the Fig. 5 ) Right second bearing pocket 24 is here divided into two partial pockets 24a, 24b. Each partial pocket 24a, 24b is supplied with hydraulic fluid from the supply line 26 via a supply throttle 35a, 35b. The volume flow Vp fed into the supply line 26 is again constant.

Such a subdivision of a bearing pocket 24 into two partial pockets is of course also possible with the first storage pocket 12 and with the other second storage pocket 23.

The subdivision of the bearing pocket 24 into two or more partial pockets 24a, 24b has the advantage that it is possible to counteract a tilting of the bearing housing 9 relative to the machine housing 11.

Fig. 6 schematically shows different frequency characteristics that occur in the winding device. Here, a diameter d of the winding roller 5 is applied horizontally to the right and vertically upwards the respective frequencies f. The representation is to be understood qualitatively.

The rotational frequency of the support rollers 2, 3 is designated by fr. The rotational frequency of the winding roller 5 is denoted by fw. It can be seen that the rotational frequency of the support rollers 2, 3 remains constant after a run-up phase. The rotational frequency of the winding roll, however, decreases after reaching a maximum rotational frequency, because the material web is wound at a constant speed, While the diameter of the winding roll 5 grows.

Considered is the case where the rotational frequency fr of the carrier rollers 2, 3 has reached the maximum constant rotational frequency fR.

A natural frequency of the support roller 2, 3 is f01A. located. It can be seen that the rotational frequency fr of the carrier rollers 2, 3 is greater than the natural frequency f01A of the malt assembly, which is formed in each case from a carrier roller 2, 3 and their bearings 7, 8 at the two ends.

With f02A an even lower natural frequency of the Walzenänordnung from support roller 2, 3 and bearings 7, 8 is shown. This natural frequency belongs to the reduced rotational frequency of the winding roll.

In order to make the difference to the prior art clear, also a frequency f0R is drawn, as it has been used as the natural frequency of the support roller 2, 3. The natural frequency was usually chosen it was 1.3 times the maximum rotation frequency fR.

In the present case, however, the natural frequency f01A is selected to be 10 to 20% lower than the maximum rotational frequency fR, or even lower, when referring to the reduced rotational frequency.

Claims (15)

1. Device for winding a material web into a wound reel (5), having at least one roll (2, 3) on which the wound reel (5) rests during winding and which rotates during winding, the roll (2, 3) being supported in a bearing device having a bearing (7, 8) at each roll end,
   characterized in that
   the bearing (7, 8) has a hydrostatic support having at least one first bearing pocket (12), which is fed with hydraulic fluid.
2. Device according to Claim 1,
   characterized in that
   the bearing pocket (12) is fed with a constant volume flow (Vp) of hydraulic fluid.
3. Device according to Claim 1,
   characterized in that
   the bearing pocket (12) is connected via a throttle to a constant inlet pressure.
4. Device according to one of Claims 1 to 3,
   characterized in that
   the bearing pocket (12) is connected via a throttle (18) to a pressure reservoir (17).
5. Device according to Claim 4,
   characterized in that
   the pressure reservoir (17) is formed as a gas pressure reservoir.
6. Device according to Claim 4 or 5,
   characterized in that
   the throttle (18) has an adjustable throttle resistance (22).
7. Device according to Claim 6,
   characterized in that
   the throttle (18) is connected to a positioning device that can be actuated from outside.
8. Device according to one of Claims 1 to 7,
   characterized in that
   the hydrostatic support is connected in series with a spring arrangement (31, 32; 33).
9. Device according to one of Claims 1 to 8,
   characterized in that
   at least one further hydrostatic support is provided, having at least one second bearing pocket (23, 24) which has a different direction of action from the first bearing pocket.
10. Device according to Claim 9,
    characterized in that
    at least one bearing pocket (24) is subdivided into two partial pockets (24a, 24b), each of which is fed via a supply throttle (35a, 35b).
11. Device according to one of Claims 1 to 10,
    characterized in that
    the bearing device has a stiffness which varies with the excitation frequency.
12. Device according to Claim 11,
    characterized in that
    the bearing device has a static stiffness which is greater than the stiffness of the roll (2, 3).
13. Device according to Claim 12,
    characterized in that
    the static stiffness is at least twice the stiffness of the roll (2, 3).
14. Device according to Claim 12 or 13,
    characterized in that
    the bearing device has a dynamic stiffness which is lower than the stiffness of the roll (2, 3).
15. Device according to Claim 14,
    characterized in that
    the dynamic stiffness is at most 50% of the stiffness of the roll (2, 3).

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