FI117301B - Storage of a web processing machine's roller and method of damping the roll vibration - Google Patents

Description

117301

Rolling machine bearing and method of damping roll vibration

The invention relates to a bearing of a nip-forming roller having an idler housing for attachment to the structures of a web-processing machine, a roller bearing 5 having at least a frame member in contact with the bearing housing, and an opening for the shaft of the roll transverse to the nip load line. The invention also relates to a method for damping roll vibration in a nip between compressed rolls of a roll processing machine stack, wherein the method comprises deflecting at least one roll in a transverse direction of the loading line of the roll stack nip.

In web-processing machines, such as calendars, there is an oscillation phenomenon in which the rolls of the pressed track rolls start to oscillate so that the soft roller coatings are depressed. These depressions produce a corresponding flap-like pattern on the web to be treated. Wunzenblatt för Papierfabrikation, Paper No. 4, 1976, by Gunther Boos, "Die Ursache von Glattwerksmarkierung (Barring) im Papier und der Escher Wyss - Nipcowalze", pp. 133-139, in La-20 and Art. barring, its mechanism of action and birth. The article discussion section on page 139 mentions e.g. that barring formation can be prevented by: moving one roll of the roll stack during use, i.e. transversely to the loading direction, during operation.

In the context of the present invention, the nip loading line, or generally the loading line, means a direction corresponding to a line corresponding to the line of rotation of at least two adjacent, nip-contacting rolls of the processing machine or nip-forming nipples. the direction defined by the line between the axes of rotation of the outermost rolls, for example, in the upper supercalender, the upper and lower rollers. In this latter case of a roll stack; . The load lines defined by the two adjacent rolls and the outermost rollers of the roll stack may not be parallel.

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WO 99/25921 is known in the art which discloses a method for detecting fouling or damage of a roll surface passing through a nip. According to the method, the vibration in the structure is observed and analyzed, after which the necessary steps can be taken to eliminate the vibration.

EP 1015695B1 is also known in the art, which discloses a method and apparatus for damping oscillations in a road arrangement in a paper machine or paper finishing machine, in particular in a nip pressed against one another without changing the machine speed. The arrangement is based on a dynamic attenuator, that is, adjusting the oscillation frequency of the movable pulp at the end of the bar to ωο as close as possible to the characteristic frequency of the rotating roll, whereby this movable pulp vibrates at the same frequency but in opposite Because the oscillation frequencies that occur are the result of very complex situations, such as the spring effect of this indentation caused by the seam or web unevenness to the roll coating, the dynamic attenuator frequency must be adjustable to suit the current oscillation frequency.

Also known from the prior art is US 2002 / 0024415A1, which discloses a vibration damping of a calender roll stack as shown by Boos, such that the rolls of a roll stack pressed against one another are deflected in the transverse direction. It is disclosed that the vibration level of the roll preferably of the middle roll is monitored and analysis is performed to determine the wavelength of the oscillation occurring or occurring relative to the circumference of the roll or as a multiple of the circumference.

·: ··: 25 Then, by varying the roll in a direction transverse to the compression direction of the roll stack, the resulting vibration pattern can be altered to ·· ·: much so that the flange of the soft coating of the roll periodically! ···! this pattern cannot become harmful. According to the publication, the roller is preferably moved laterally from about one-eighth. 30 or one quarter of the specified wavelength. The lateral displacement is proposed to be performed by an eccentric, linear guide, folding linkage or spindle screw.

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The object of the invention is to provide a roller bearing which can implement the teachings of Giinther Boos in a 1976 article and which can: · · ··: 35 easily, cheaply and simply reduce the tendency of compressed *: **: rolls to start oscillating, - 3 117301 unevenness in the web passing through the nip between the press rolls. It is also an object of the invention to greatly simplify the structures disclosed in US 2002 / 0024415A1 in the crossing of a roll movable transverse to the compression direction of the calendar. It is also an object of the invention to provide the possibility of a continuous change in the calendering geometry, as a result of which the onset of the oscillation phenomenon, which often begins gradually, can be prevented.

It is also an object of the invention to be able to influence the spring constants of the bearings disclosed in Boos's article, which in their part influence the vibration properties of the entire web-processing machine.

The bearing according to the invention is characterized in that at least one space is provided between the bearing housing and the peripheral element, which is located at a distance from the load line and to which a fluid pressure medium can be introduced to deflect the roll transversely to the loading line

The method according to the invention, in turn, is characterized in that in the bearing of the roll, a fluid pressure medium is introduced into the space between the bearing housing and the peripheral element at least one distance away from the load line, thereby deflecting the roll transversely to

* «· / 7 This provides a bearing and vibration damping method i» ·; simple and reliable, contains very few components and allows the geometry of the strip concept machine to be modified during use so that no harmful vibration phenomenon can be created or the vibration underway is terminated.

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According to an advantageous feature of the invention, the bearings have means for boiling. determining the position of the acoustic element relative to the bearing housing. Thus, the state of the art at each time in the structure is known, and one can be assured that the movement at both ends of the roll has been similar, i.e. the roll remains in a straight and desired position relative to the rolls in contact with the other rolls.

According to another advantageous feature of the invention, the peripheral element is an arm-*: ·· outer bearing periphery or a stiffening element coupled to this outer periphery.

117301 4 Γ 'I In conventional bearings, the bearing housing supports the actual bearing so that all forces exerted on the structure are transmitted from the rotating roll to the bearing housing mounting base, i.e. the load levers or the frame. In some cases, for example when the web processing machine is a calender, the forces exerted on the bearings can be quite high. The structure of the actual bearing may not tolerate such a force if the bearing were as if pinched between two planar surfaces and the bearing was free to deform from a circular oval. Thus, lateral deformation must be prevented and may conveniently be provided by a separate stiffening element 10 which prevents unwanted deformation of the actual bearing peripheral, i.e., rolling or sliding bearing bearing element. This is accomplished by designing the stiffener element to be capable of transmitting a nip load force from the bearing housing to the bearing such that the load deformation of the bearing is maintained at a level such that the deformation of the bearing is less than that allowed for the bearing used.

In the following, the invention will be described with reference to the accompanying figures, in which: Figure 1 is a side view, i.e. transverse to the web direction, of the bearing structure; Figure 2a shows one alternative path of the axis of rotation of the roll,

Fig. 2b shows another alternative path of the axis of rotation of the roll,

Figure 2c shows a third alternative path for the axis of rotation of the roll.

Figure 1 shows bearing 2: A of a web-processing machine, such as a calendar, insofar as it is essential for understanding the invention. Laake- *: * '? The main function of the winding 2 is to allow the roll 3 to rotate and to transmit the supporting forces necessary for the web processing between the roll 3 and the web processing machine: body. The invention also provides one additional function for bearings: • Drug also enables active vibration damping to be applied when required. The figure shows a second aperture in the bearing housing 4: ... 30, which provides spaces 7 on the sides of the peripheral element 6 which, in turn, allow the transverse movement of the peripheral element 6 with respect to the bearing housing 4. The space 7 is located at a distance from the load line V ·! L. In Figure 1, the roller 3, i.e., in practice, the roller shaft 31, is shown in the middle of its transverse movement path according to the invention. The rotation axis A of roll 3 is preferably distributed to one end Cpi, Cp2 of its trajectory C so that the structure behaves as steadily as possible.

• * 117301 5

In Fig. 1, the peripheral element 6, such as the outer periphery of the bearing 61 or the stiffening ring 62, is shown as a regular-shaped ring, but in practice it may be of other shape. An advantageous feature of the structure is that it is sufficiently rigid to transmit the required forces and at the same time is movable with respect to the bearing housing. The mobility may be, for example, translation along a suitable surface, or rotation about a suitably selected point, or a combination thereof. For example, when selecting a circular shape for a circumferential element, mobility is conveniently achieved by scrolling the peripheral element 6 along an opening in the bearing housing 4. Of course, the use of a pressurized-10 material such as hydraulic oil or the like requires the sealing to be arranged in such a way that this pressurized medium cannot enter into harmful locations or leak out of the bearing. One clear sealing object is space 7 or spaces 7 with the roll in position Cp1 or position Cp2. Commonly used solutions become seals.

According to a preferred feature of the invention, the bearing has means for determining the position of the peripheral element relative to the bearing housing. These means 11 may be, for example, optical, mechanical, inductive or other electrical sensors or similar instruments for reliably determining the current state and position of the structure at any given time. The goal of Ta-20 is to control the structure so that the transfer at both ends of the roll is or has been similar, i.e. the roll remains in a straight and desired position relative to the other rolls in contact with said roll.

* · · * • «* ·: Preferably, the roll is movable so that the frequency of movement is user-transferable. One embodiment of this is that the roll can be oscillated by the pressure medium in the transverse direction of the nip loading line. The extent of the movement, i.e. the distance between the station Cp1 and the station Cp2, results from the arrangement of the f ": space 7. One possible embodiment is that the space 7 is arranged so that the roll is displaceable from the nip loading line at least 10: 30 mm, preferably 40 mm, even more when needed.

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Since the agility shown affects the flexibility of the structure, which in turn affects the vibration behavior of the whole structure, it is preferable that this. flexibility can be structurally managed. One way of controlling this is to provide the bearing with locking means for locking the peripheral member * '35 to a fixed position relative to the bearing housing. This clearly stiffens the structure compared to the use of pressure medium alone to lock the peripheral element 6 relative to the bearing housing 4.

It is advantageous for the vibration damping method that the position of the peripheral element relative to the bearing housing is monitored and adjusted as necessary in the transverse direction to the load line at least 10 mm, preferably 40 mm. In order to prevent the occurrence of roll vibration, the operating conditions are monitored and analyzed, based on the analysis, it is decided to change the geometry of the web processing machine, whereby the position of the roll relative to the load line is changed continuously or less frequently. The operating conditions may be monitored, for example, by means of suitably located accelerometers, optical sensors for monitoring the surface of the web or roll, or other suitable means. The information obtained from these is processed and analyzed by the control system or a system attached thereto. Most advantageously, the system detects oscillations that begin at the earliest possible stage, so that it can be prevented as easily as possible. The decision to change the geometry of the web processing machine is made programmatically in the control system or at the user's choice. It is also advantageous for the whole that the roll deflection can be switched off and the movement of the circumferential element relative to the bearing housing can be prevented by means of a mechanical coupling. This can be accomplished, for example, under driving conditions such as a given running speed, nip load, web material properties and composition, etc., which have been found to be less sensitive to the generation of harmful vibrations.

• · ♦; Figures 2a, 2b and 2c show various possibilities for arranging the movement path C of the roll axis 3/25 relative to the nip loading line. In Fig. 2a, the end point Cp2 of the movement path C is arranged on the load line L. The other end point Cp1 of the movement path C i is arranged at a suitable distance from the load line L. In Fig. 2b the movement path C intersects the load line L and the end points Cp1 and Cp2. In Fig. 2c, the trajectory C does not intersect the load line L, but both points Cp1 and Cp2 are the load line ···. on the same side of the ice. The good thing about this arrangement is that it is structured. However, on the other hand, the drawback is that the effect of the roll transfer "on vibration, i.e. the technical power, is less than that of the arrangements shown in Figures 2a and 2b. As shown in Figures 2a-c, the trajectory C can be straight or curved.

* 7 117301

Reference numerals appearing in the figures: I web processing machine, for example calender 5 2 bearing 3 roll 31 roll shaft 4 bearing housing 5 bearing ίο 6 circumferential element 61 bearing outer circumference 62 stiffening element 7 space L load axis 15 A rotation axis of roll 3 roll axis

Cp1 Position of axis of rotation of roll 1

Cp2 Rolling Rotation Axis Position 2 II Means for Determining Position 20 • f i ♦ M M M M M «* • M M M »• M t * • #« * * Φ • · # • · ♦ · »» * • • • 9 · Ψ · «·» • * «♦ *« * «• · •« • »f §» ♦

Claims (14)

1. Bearing (2) of a nip-forming roller having a bearing housing (4) which can be attached to the structures of the web-processing machine (1), a bearing (5) allowing rotation of the roller (3) having at least a peripheral element (6) in contact with the bearing housing (4); and an opening for the roll shaft (31), the roll (3) being adapted to be mounted on the bearing (2), being movable in addition to rotation both parallel to the nip load line (L) and transverse to the nip load line. at least one space (7) disposed at a distance from the loading line (L) to which a flowing pressure medium can be introduced, which allows the roll (3) to be deflected transversely to the nip loading line (L) by moving the circumferential element (6) 4). Bearing according to claim 1, characterized in that it is provided with means (11) for determining the position of the peripheral element (6) in relation to the bearing housing (4). Bearing according to Claim 1, characterized in that the movement path (C) of the axis of rotation of the roll (3) intersects with or without cutting the load line (L) or is terminated on the load line (L). Bearing according to Claim 1, characterized in that the circumferential: T: element (6) is the outer circumference (61) of the main bearing or the stiffening element (62) coupled to this outer circumference. • Bearing according to claims 1 and 4, characterized in that the structure of the stiffening element (62) is shaped such that it is able to connect the load force of the nip from the phage housing (4) to the bearing (5) such that the bearing force caused by the bearing the deformation remains at a level at which the deformation is less than the deformation allowed for the bearing (5) used. ·· * m • · · • m Bearing according to Claim 1, characterized in that the roll (3) V * i 30 can be oscillated by the pressure medium in the transverse direction of the nip loading line (L). »• ·» ····· • * 117301 Bearing according to claim 1, characterized in that the space (7) is arranged so that the roll (3) can be displaced from the nip loading line (L) by at least 10 mm, preferably 40 mm, if necessary even more. Bearing according to Claim 1, characterized in that it has locking means for locking the peripheral element (6) in a fixed position relative to the bearing housing (4). 8 117301 A method for damping roll vibration in a nip between compressed rolls (3) of a roll stacking machine, wherein at least one roll (3) is deflected transversely to the loading line (L) of the roll stack nip, characterized in that the bearing (2) (4) and at least one space (7) located at a distance from the load line (L) between the peripheral element (6) and a filing pressure medium for guiding the roll (3) transverse to the nip load line (L) by moving the peripheral element (6) ). Method according to claim 9, characterized in that the position of the peripheral element (6) in relation to the bearing housing (4) is monitored and modified as necessary. Method according to Claim 9, characterized in that the roll 20 (3) is deflected at an angle of at least 10 mm, preferably 40 mm, in the transverse direction to the load line (L), if necessary even more. «· S * * Method according to Claim 9, characterized in that, in order to prevent the generation of roll / vibration, the operating conditions are monitored and analyzed, based on the analysis, it is decided to change the geometry of the web-processing machine, changing the roll position relative to the load line continuously or less frequently. A method according to claim 9, characterized in that the deflection of the roller • '·' '. * ··] can be switched off and the movement of the peripheral element relative to the bearing housing T can be prevented by mechanical coupling. i t · • ··. ···! 3o Method according to claims 9 and 12, characterized in that the decision to change the geometry is made programmatically in the control program or according to the choice of the user. ····· ® m 117301