This application claims priority on Finnish Application No. FI 20075476, Filed Jun. 21, 2007, the disclosure of which is incorporated by reference herein.
Not applicable.
The present invention relates to a support arrangement of a roll in a fibrous-web machine. The invention generally relates to supporting a bearing of a roll of a fibrous-web machine or an equivalent shaft to the frame structure. Particularly, the invention relates to a roll of a device or a section of a paper or board machine and supporting its bearing to the frame structure when external force applies to the roll. Such external force can be caused e.g. by another roll, a support fabric or a web reel.
The vibration of rolls is a great problem with present-day fibrous-web machines, inter alia, due to the increase in operating speed. Traditionally, the rolls are fastened in the foundation as rigidly as possible, this is particularly the case with the carrier rolls of a slitter-winder.
Specifications WO9849394, WO0004227 and WO0004228 describe arrangements in which in the bearing housing of a roll of a paper machine has been arranged a tunable vibration damper. In the arrangements presented in the specifications, the tuning of the frequency of the vibration being damped has been implemented by changing the position of the mass in the vibrating rod or, alternatively, by changing the volume of the mass. When the access to the damper is relatively easy, the tuning can be changed even during the operation of the machine. In these, the damper is outside the roll, whereby it, inter alia, occupies considerable space. This kind of an arrangement does not always provide good enough damping.
FI patent 94458 describes a method and apparatus for controlling the vibration of the rolls of a paper machine. In the method, the positions of the critical speed ranges of the roll are changed during run. Critical speed is changed by changing the mass and/or the rigidity of the roll and/or the support point of the roll. As a possibility is presented changing the rigidity of the end bearing of the roll. Between the washer of the bearing housings of the end bearings and the frame, intermediate pieces of elastic material can be installed. By adjusting the force with which the bearing housing presses the intermediate pieces against the frame, it is possible to adjust the rigidity of the fastening of the bearing housings. Said pressing force can be adjusted by means of a cylinder device or a screw. A problem of such an arrangement is, however, that simultaneously as the critical speed ranges are changed by making the support elastic, the static rigidity of the support suffers. Particularly in such an arrangement, the static rigidity of the support also weakens in such directions in which it is not desired. This causes problems particularly in targets demanding accurate setting, such are e.g. nip contacts between the rolls and between the roll and the web reel.
Specification JP 3082843 describes an arrangement for minimizing vibrations in a roll. The drive motor of the roll is elastically fastened in the frame. The fastening comprises a rubber intermediate piece enduring vibration between the base plate of the fastening part and the frame. The fastening bolts of the base plate extend through the frame plate into a cylinder fastened on the lower surface of the frame plate in which they are fastened in a piston in the cylinder. Below the fastening bolt heads, there are rubber sleeves, whereby the fastening of the base plate is provided floating. On the inner surface of the cylinder, there is a projection which limits the upward motion of the piston in the cylinder. Between the cylinder ceiling and the upper surface of the piston, there is a spring and, between the lower surface of the piston and the bottom of the cylinder, there is a pressure space in which compressed air is the pressure medium. The piston is run with compressed air first against the projection of the inner surface of the cylinder, whereby minimum pressing force is applied on the rubber intermediate pieces and sleeves. When the pressure of compressed air below the piston is decreased, the piston moves downwards from the force of the spring being above the piston, whereby greater pressing force is applied on the rubber intermediate pieces and rubber sleeves. With the pressure of pressure medium being below the piston, it is then possible to adjust the rigidity of the fastening of the roll. A problem of the arrangement presented in this specification is also that making the support more elastic causes easily that elasticity, particularly its direction, is not sufficiently controlled.
The object of the invention is to provide a support arrangement of a roll of a fibrous-web machine, which arrangement comprises a first frame part in which the roll is supportable from its end and a second frame part in which the first frame part is fastened by means of an elastic fastening, which support arrangement with allowed elasticity has at least one certain determined direction and which is substantially statically rigid in other directions.
This object is achieved according to the invention such that the support arrangement comprises a motion direction control arrangement for controlling the direction of the motion allowed by the elastic fastening in a way determined by the direction control arrangement.
With this arrangement, such an effect is achieved that in the support the dampening of vibration is provided effective without endangering the rigidity of the support in such directions which require rigidity.
A direction control arrangement of a support arrangement of a roll according to an embodiment of the invention comprises at least one support part which is fastened in both the first frame part and the second frame part. The support part is arranged according to the invention substantially perpendicular in relation to the direction allowed by elasticity and it is thin in the direction allowed by elasticity. A support part arranged this way prevents the mutual motion of the first piece and the second piece mainly in other than the substantially perpendicular direction in relation to the plane of the support part.
Advantageously, the thin support part is a piece having a long deformation zone. The thickness of the support part is typically at the most 10% of the length of its deformation zone.
In a support arrangement of a roll according to an embodiment of the invention, the direction control arrangement comprises a pivot arranged in a second fastening lug comprised by the first frame part which lug substantially allows only rotational motion. By means of the pivot, motion is prevented in non-desired directions and allowed in a desired direction.
The pivot comprises according to an embodiment at least two support parts being on planes intersecting on a joint intersection line.
According to an embodiment of the invention, the support parts comprise binder parts extending in the longitudinal direction of the support part at a distance from each other such that from each gap determined by the distance a binder part of another support part/other support parts used in pivoting can be brought through.
The elastic fastening comprises an elastic piece arranged between the first and the second frame part.
Other additional features characteristic of the invention are illustrated in the accompanying claims.
In this context, a paper machine means different fibrous web manufacturing or processing apparatuses or their sections, such as paper machines, board machines, press sections, reelers, calenders and slitter-winders. The invention is well applicable, inter alia, in connection with the carrier rolls and/or press rolls of the winding section of slitter-winders.
Other characteristic features of the method and apparatus according to the invention are illustrated in the accompanying claims.
The invention and its operation will now be described with reference to the accompanying schematic figures.
The rolls of the fibrous-web machine are typically supported from their ends in the frame or foundation of the machine. The structure of the roll can be such that it comprises a hollow shell and heads arranged to its ends in which head there further is a quite short shaft. Such a roll is rotatably supported by the above-mentioned shafts in the frame or foundation of the machine. The structure of the roll can also be such that it comprises a frame stationary when operated supportable to the frame from its ends and a shell rotatably arranged around it. In such a roll, the shell can even be to some extent elastic, and a shoe has been arranged inside it to support the shell, whereby the roll is often called a long-nip roll.
A support arrangement 10 of a roll of a fibrous-web machine according to an advantageous embodiment of the invention shown in connection with
The first frame part 12 is fastened to the second frame part 22 by means of an elastic fastening. In this embodiment, it has been implemented in the following way. Through the fastening lugs 16 of the first frame part 12 is arranged a drawbar, bolt or equivalent 28, one or more. The bolt 28 extends through the fastening lug 16 and is fastened on the inner thread of an opening of the second frame part 22. Between a plate 29 between the fastening lug 16 and the head of the bolt 28 and the fastening lug 16 and the second frame part 22 are arranged elastic pieces 32 which enable elastic fastening. The bolts 28 are tightened against separate sleeves 30. The sleeves 30 extend from the plate 29 of the bolt 28 to the surface of the second frame part 22, whereby the length of the sleeve 30 here determines the compression of the elastic pieces 32. In order to be able to control the direction of the motion enabled by elasticity, there is a motion direction control arrangement 34 in the embodiment of
To facilitate understanding the invention, it is possible in a practical situation to determine the so-called machine direction MD, cross direction CD and vertical direction Z, whereby the cross direction in the figure is perpendicular in relation to the plane of the figure. In the following description, these will also be used as assistance in indicating directions.
The motion direction control arrangement 34 comprises in the embodiment of
In the embodiment of
For minimizing the motion in the direction of the plane of the support part 36, the bearing housing i.e. the first frame part 12 and the second frame part 22 comprise control surfaces 40 substantially parallel to each other. The direction of the control surfaces joins the direction of the allowed motion and is substantially perpendicular in relation to the direction of the plane of the support part 36.
In this embodiment of
Particularly in the carrier-roll applications of the winding sections of the slitter-winder, it is essential that clearances are minimized and the elastic motion takes place within the limits allowed by the elastic pieces. For maximizing the damping capacity of the bearing housing, the bearing housing is manufactured such that an as large as possible part of motion taking place due to dynamic load in the housing will occur in a part which damps vibration well.
It is thus essential to construct the support such that it is as much as possible supported by the damping part and the direction control arrangement in the direction of the motion of the vibration, sufficiently rigid in other directions and substantially clearance-free in all directions.
Typically, the support of the rolls of fibrous-web machines, e.g. a carrier roll of a slitter-winder, has to be statically at least so rigid in all directions that the lowest natural frequencies of the roll are somewhat higher than the greatest rotational frequency of the roll.
The first frame part 12 is fastened to the second frame part 22 by means of an elastic fastening. In this embodiment, the elastic fastening has been implemented such that the first end of the first frame part 12 is fastened by the bolt joint 28 to the second frame part 22 such that the fastening lug 16 of the first frame part is tightened by one or more bolts 28 between the elastic pieces 32.
In the embodiment of
In practice, the direction in which motion is allowed is chosen case-specifically. It can be e.g. precisely the vertical direction.
The first fastening lug 16 of the bearing housing, which is in
In the embodiment of
The pivoting according to the invention shown in
At the end of each binder part in the embodiment of
The support part can be formed of one plate 68 or a stack formed by several single plates 68.1, 68.2, 68.N on top of each other. Both ways are usable as such, but the stack of plates enables the greater deflection of the pivot i.e. it is possible to arrange the rotational angle larger by using the stack of plates.
In the pivot 50 shown in
By the length of the deformation zone, i.e. the zone for the part of which the support part, or in more detail its binder part, is free to deflect in the installation, the rigidity of the pivoting can be affected, among others.
In
The first fastening lug 16 of the first frame part 12 is also here tightened with the bolt 28 between elastic pieces 32 and 32′. The elastic piece 32 above the fastening lug is arranged here into connection with the bolt, but the elastic piece 32′ below is on the lower surface of the first frame part 12 so that the bolt does not go through it. Between the elastic piece 32′ below and the second frame part 22 (the order can also be reversed), there is a distance adjustment apparatus 70. By the distance adjustment apparatus, the position between the first 12 and the second frame part 22 can be adjusted in relation to each other. Such a requirement can be in some targets of application process-technical adjustment, such as that of nip force, but principally its purpose is to compensate the permanent deformations of the elastic pieces which can occur during use as time passes. The arrangement also comprises a distance or position sensor 72 based on the measuring data of which the distance adjustment apparatus is adjusted and the position of the first 12 and the second frame part 22 in relation to each other is set. The arrangement can also comprise a control unit 74 which receives the measuring data of the distance or position sensor 72 and processes it e.g. by sending a measurement value to be viewed on the control apparatus, by alarming of a distance going outside set values or by directly controlling the distance adjustment apparatus 70 by a correcting measure.
The distance adjustment apparatus 70 comprises in this embodiment two pieces 76 on top of each other the corresponding surfaces of which are inclined in different directions forming a wedge-shaped gap. Into this gap, a wedge piece 78 is arranged. At the narrower end of the wedge piece, there is a screw device 80 which, when being tightened, is arranged to provide pull in the wedge piece causing counter force in the pieces 76 being on top of each other on its opposite sides. This provides the motion of the wedge piece in the gap in relation to the pieces 76 and, from the effect of their shapes, the motion of the pieces 76 farther from each other and further the motion of the first frame part farther from the second frame part. The arrangement also operates in a corresponding way in the other direction.
It should be noticed that only a few of the most advantageous embodiments of the invention were described above. Thus, it is evident that the invention is not limited to the above-mentioned embodiments, but it can be applied in many ways within the scope defined by the enclosed claims. Also, characteristics described in connection with different embodiments can be used in other embodiments if technical possibilities exist.
Number | Date | Country | Kind |
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20075476 | Jun 2007 | FI | national |