FI110713B - Damping device for damping vibration of a pair of rollers forming a nip in a paper or cardboard machine - Google Patents

Description

110713

Damping device for damping the vibration of a pair of nip-forming rollers in a paper or board machine Dämpningsanordning för dämpning av vibrationer hos et Valspar som bildar et nyp i en pappers-eller

The invention relates to a damping device as defined in the preamble of claim 1.

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In paper machines and paper finishing machines, vibration is a quite significant problem and vibration problems have become more evident in the current systems in the pursuit of ever higher speeds. There are several possible sources of vibration in papermaking machines, some of which are rolls and cylinders, which comprise a large mass rotating at considerable speed. Naturally, the rolls are designed to maximize dimensional accuracy during manufacture, and the rolls are also balanced to eliminate vibrations.

20 However, current paper machines and paper finishing equipment are increasingly using soft-coated rollers, which can provide a significant source of vibration when used.

Such rolls are used, for example, in on-line and off-line calenders, coating machines, adhesive presses, supercalenders and the like, wherein said soft-coated roll forms a nip with another roll. A paper web is passed through the nip and possibly: ***; felt, wire or the like. In such a nip roll solution, when the wire, felt or web seam passes through the nipple, significant impurities, or anything that causes a significant change in the thickness of the passage through the nip, the coating is forced to ... as an oscillating spring. For example, in the · · »adhesive press and the adhesive press type coating machine, the nip • · • · is formed by two rolls with one nip roll installed *! by means of the bearing housings directly on the frame structure of the device in question, while 35 opposing rollers are mounted from their bearing housings on the load arms which .1. is articulated with the machine frame structure. In this case, especially the load ♦ w • w *** begins. a roll mounted thereon vibrates, whereby the coating of the soft surface roll is modified, as a result of which the vibration is intensified and the roll begins to resonate.

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One common technique in the art for eliminating such vibrations is to change the machine speed so that at that speed the vibration is no longer amplified but begins to damp. Vibration problems have thus limited machine speed.

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Applicant's FI patent 82127 discloses a method and apparatus, in particular for damping vibrations of rolls comprising a pair of rollers forming a nip of the press section. In the method, the nip is shifted to the desired traction sheave release so that the load exerted by the loading means of the pair of rollers is stabilized to a controlled level. When the desired tread line pressure is achieved and the load provided by said loading devices is stabilized, the bearing housings of rollers comprising a pair of rollers are rigidly coupled to each other so as to prevent their mutual movement.

Applicant's FI Patent 85166 discloses a further method and apparatus for damping the vibration of rolls comprising a pair of rolls forming a nip, in particular a press section nip. In the method, the bearing housings of rollers comprising a pair of rollers are supported by a damping device for damping and absorbing the mutual movements of rollers comprising a pair of rollers due to vibration. The damping is performed by a hydraulically actuated piston cylinder cylinder. . a damping device comprising a field for directing and removing hydraulic pressure medium. The damping device amplifies the flow of hydraulic pressure medium caused by the mutual movement of the piston-cylinder structure by the rollers of the pair of rolls and said amplified flow by the displacement of said vibration damping to provide a vibration damping.

The main features of the damping device according to the invention are apparent from the characterizing part of claim 1.

The damping device according to the invention is particularly well suited for use with a nip forming roll pair in which a roll nip is formed between a soft surface and a hard surface roll. In such structures, 35 · may result from the modification of the soft surface roll coating.

110713 fast growing vibrations that need to be controlled. Applications of the invention include, for example, an adhesive press and a coating device.

This is done in the invention by either connecting the bearing housings of the rolls of the nip-forming roller pair 5 with a lamellar pressure-adjustable coupling module or by connecting the bearing housings of at least one roller with said coupling module to the machine frame. Thus, depending on the amount of pressure applied to the connection module, various modes can be achieved and thus affect the stiffness and damping between the bearing housings or between the bearing housings and the machine frame.

The pressure applied to the side surfaces of the joint module affects the mechanical friction between the contacting surfaces of the joint module lamellae. The greater the clamping force applied, the greater the 15 force required to move the lamellae relative to one another due to the greater mechanical friction.

The invention will now be described with reference to the accompanying drawing, in which details, however, are not intended to be limited solely by the invention.

. The figure schematically shows a device according to the invention in sectional view.

The figure shows a sectional view of a pair of roller bearing housings 11, 12 interconnected by a lamellar pressure-adjustable F coupling module la 20. 12 secured to the second lamella-like connecting element 22, 30 which in the closed position overlap. A pressing force F can be applied to the side surfaces of the second connecting element 22, for example by means of a hydraulic pressure device, by which the lamella members 21a, 22a of the connecting elements 21, 22 are pressed against each other. Naturally, said connection modules 20 are located at both ends of the rolls between the bearing housings 11, 12. The nipple j ”35 is closed by a movement in the plane of the bearing housings, the trajectory * · /« ... being the arc of the circle.

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Depending on the magnitude of the clamping force, the following three modes of operation are obtained: F = 0, i.e. the open state, in which the lamella members 21a, 22a do not transmit forces. This mode can be used for nip locking and quick opening.

5 0 <F> Fk, i.e. an intermediate space in which the lamella members 21a, 22a are able to move frictionally relative to each other. The magnitude of the force F can influence the frictional force between the lamella members 21a, 22a and thereby the attenuation between the bearing housings 11, 12. Fk is the force sufficient to lock the lamellae 10 together by means of friction in the current configuration.

F> Fk, i.e. the closed state, in which the force F is large enough to lock the connecting members 21, 22 together. In this state, the connecting element acts as an elastic part of the 15 systems, while its stiffness alters the overall rigidity of the system.

Thus, in addition to damping, one junction module 20 according to the invention can change the stiffness of the system and, at the same time, its specific frequency 20 between two discrete values. By connecting a plurality of junction modules 20 according to the invention in parallel, several discrete stiffness values can be achieved.

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Instead, the damping between the bearing housings 11, 12 · · 1 · ’25 can be infinitely controlled by the connection module 20 according to the invention, since the frictional force i i‘;; The F value can be infinitely adjusted. Here, the kinetic energy of the system is converted into frictional work.

In the figure, the connection module 20 is mounted between the bearing housings 11, 12, but the connection module 20 can also be mounted between the bearing housings 11, 12 and the machine frame. In this case, the bearing housings e of only one of the bogies may be supported on the machine frame by said connection modules 20, or the bearing housings of both rollers may be supported on the machine frame by said connection modules 20.

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The claims which follow, within the scope of the inventive idea defined, may vary from the above only by way of example.

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Claims (4)

A damping device (20) for damping vibrations of a pair of nip-forming rollers in a paper or board machine, characterized in that the damping device (20) comprises two interlocking connecting elements (21, 22), on which side forces (F) are applied , (22) the mechanical friction between the opposing surfaces of the interleaved lamella members (21a, 22a) is adjustable between three modes of operation: 10. F = 0, i.e. the open space in which the lamella members (21a, 22a) move freely relative to each other - 0 <F> Fk, i.e. the space in which the lamella members (21a, 22a) move under the action of mechanical friction with respect to each other, where (Fk) ) is the force sufficient to lock the lamella members (21a, 22a) to each other by mechanical friction in the current configuration - F> Fk, i.e. the closed state in which the lamella members (21a, 22a) are locked together by mechanical friction. 20 2. A pair of nip-forming rollers, characterized in that each of the opposite bearing housings (11, 12) of the rolls of the roll pair is supported by one or more damping devices (20) according to claim 1. 3. A pair of nip-forming rollers, characterized in that the bearing housings (11, 12) of either roll of a pair of rolls are supported on the machine frame by one or more V damping devices according to claim 1. (20). «Ϊ 1 - yv Nip-forming roll pair, characterized in that the bearing housings (11, 12) of each roll of the roll pair 30 are supported on the machine frame by one or more parallel damping devices (20) according to claim 1. i * υ «· w iti * • · • · · • · Patentkrav 110713