Bearings – Rotary bearing – Fluid bearing
Reexamination Certificate
1999-05-07
2002-01-01
Footland, Lenard A. (Department: 3682)
Bearings
Rotary bearing
Fluid bearing
Reexamination Certificate
active
06334712
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority under 35 U.S.C. § 119 of German Patent Application No. 198 22 145.2, filed on May 16, 1998, the disclosure of which is expressly incorporated by reference herein in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a deflection compensation (sag adjusting) roll having a roll jacket that is rotatably supported on a crosspiece by roller bearings and a process for rotatably supporting a roll jacket on a crosspiece in a deflection compensation roll.
2. Discussion of Background Information
Rolls such as those generally discussed above are frequently utilized in calenders for processing a material web. In particular, such rolls are utilized in paper calenders.
Generally, ram-like support elements are disposed between the crosspiece (or carrier) and the roll jacket. When pressure is applied to the support elements, they can counteract deflection or sagging of the roll jacket. Because of this, it is accepted that the crosspiece sags somewhat. In an alternative design, it is also possible to fill one half of the interior of the roll jacket with a hydraulic fluid to which pressure is applied. By reducing the pressure in the region of the rams, it is also possible to obtain a selective pressure or force load on the roll. However, the risk exists that the crosspiece will sag somewhat relative to the roll jacket. In both cases, there is a small but no longer negligible inclination of the crosspiece relative to the roll jacket in the region of the roller bearings.
For this reason, a spherical roller bearing is used on at least one end of the roll jacket. Since the outer ring rotates with the roll jacket, there are high frictional forces due to the variable load on the jacket. This results in certain wear and in reduced service life.
The types of bearings available are limited since it is necessary, in a roller bearing, to equip one end with a fixed bearing and the other end with a movable bearing.
SUMMARY OF THE INVENTION
The present invention relates to a roller bearing for use in a roll and to other type bearings. The present invention is directed to a deflection compensation (sag adjustment) roll of the type generally discussed above that includes roll bearings composed of radial load-carrying bearings (hereinafter “radial bearings”) and a hydrostatic bearing arrangement that acts in the axial direction.
Thus, in accordance with the exemplary embodiment of the present invention, the radial bearing is uncoupled from the axial bearing. Thus, it is possible to use known types of bearings for the roller bearings which can absorb only radial forces, i.e., not axial forces. The axial forces are completely absorbed by the hydrostatic bearing arrangement. Under these conditions, it is also possible to use roller bearings having convex, oblong-shaped rolling elements between an inside ring and an outside ring. In this manner, the profile radius is substantially larger than that of barrel-shaped roller bearings or spherical roller bearings. Further, the races on the inside ring and the outside ring have an appropriately large race radius. Such bearings are, e.g., available from the company SKF under the name CARB-roll bearings (see, e.g., SKF company publication: The CARB-Roll Bearing—The Better Solution, e.g., in Drying Cylinders on the Guide End). Such bearings permit relatively large angles of inclination and also relatively large axial displacements between the inner ring and the outer ring. However, these bearings are not capable of acting as fixed bearings. The axial support, as mentioned, is provided by the hydrostatic bearing arrangement. Since the hydrostatic bearing arrangement generates relatively low frictional losses and also operates relatively free of wear, in accordance with the present invention, it is possible to match the service life of the radial bearing and the axial bearing to each other.
Preferably, the bearing arrangement has a first axially oriented support surface, which works along with a piston-cylinder arrangement and a second oppositely oriented support surface, which works along with a support shoe arranged in the axial direction relative to the crosspiece. Thus, the two support surfaces are surrounded in tong-like fashion and retained by the piston-cylinder arrangement and the support shoe. Accordingly, the piston-cylinder arrangement may be used to readjust axial movements of the roll jacket to ensure that both support surfaces and their corresponding opposing elements contact each other. Of course, the axial displacement path of the piston-cylinder arrangement must be designed such that it can, if necessary, keep pace with and balance the corresponding differences in length of the roll jacket. However, these may be estimated or calculated in advance with adequate accuracy.
Moreover, the piston-cylinder arrangement may have a ring piston which surrounds the crosspiece. The ring piston may have the advantage that the compressive forces in the circumferential direction are distributed virtually uniformly everywhere, such that no periodic changes, which could result in vibration or some other phenomenon, can occur during a rotation of the roll jacket.
Advantageously, the piston and the support shoe have bearing pockets which are coupled to the same pressure source. Since the bearing pockets act on opposite sides of the roll jacket or other parts connected therewith, on which the support surfaces are located, it may be ensured that an equilibrium of forces always exists between the roll jacket and the crosspiece. This may also be true when the bearing pockets have the same active surface and are provided with the same throttle resistance in their feeder line. If the throttle resistances differ greatly, due to, e.g., different line lengths, it may also be possible to create an appropriate balance through the effective surface of the bearing pockets.
Advantageously, the support surfaces may be located on the roll jacket and the piston-cylinder arrangement, and the support shoe may be located on the crosspiece. This arrangement may simplify the feeding of the hydraulic fluid which has to be supplied only to a stationary part, i.e., the crosspiece.
Preferably, the bearing arrangement may include a disk which is acted upon on both sides. The disk may be coupled with the roll jacket and may be surrounded in a tong-like fashion by the bearing arrangement. Thus, the roller bearing, which is adjacent to the hydrostatic bearing arrangement, is the fixed bearing. The other bearing is the movable bearing.
In an alternative embodiment of the present invention, the bearing arrangement may have a first annular disk positioned on one roll end and a second annular disk positioned on the other roll end. The first annular disk and the second annular disk may be arranged to work with the piston and support shoe, respectively. In this arrangement, there is a tong-like mounting of the roll jacket, in which the jaws of the tongs are roughly as far apart as the effective working width of the roll jacket.
It may be preferable that the piston and the support shoe act on the annular disks axially from the outside. In this embodiment, the axial interior of the roll jacket may remain free for the built-in parts necessary for deflection or sag compensation, e.g., hydrostatic support shoes. When the hydrostatic axial bearing arrangement is divided into the two parts which are positioned adjacent to the roll bearing, the piston in the piston-cylinder arrangement must travel a somewhat longer path, since it must compensate for greater differences in length of the roll jacket. Thus, the radial bearing on which the support shoe is positioned is utilized as the fixed bearing, and the radial bearing on which the piston-cylinder arrangement is positioned is utilized as the movable bearing.
It may be preferable that the annular disks form an axial seal with the support shoe or the piston-cylinder arrangement. Such an axial seal may be necessary when the interior of the roll ja
Haag Rolf Van
Wenzel Reinhard
Footland Lenard A.
Voith Sulzer Papiertechnik Patent GmbH
LandOfFree
Deflection compensation roll and process for supporting a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Deflection compensation roll and process for supporting a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Deflection compensation roll and process for supporting a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2873845