U.S. patent application number 09/306851 was filed with the patent office on 2001-11-22 for deflection compensation roll and process for supporting a roll jacket on a crosspiece of the deflection compensation roll.
This patent application is currently assigned to Neil F. Greenblum. Invention is credited to VAN HAAG, ROLF, WENZEL, REINHARD.
Application Number | 20010043766 09/306851 |
Document ID | / |
Family ID | 7868084 |
Filed Date | 2001-11-22 |
United States Patent
Application |
20010043766 |
Kind Code |
A1 |
VAN HAAG, ROLF ; et
al. |
November 22, 2001 |
DEFLECTION COMPENSATION ROLL AND PROCESS FOR SUPPORTING A ROLL
JACKET ON A CROSSPIECE OF THE DEFLECTION COMPENSATION ROLL
Abstract
Deflection adjustment roll and process for supporting a roll
jacket on a crosspiece of the deflection compensation roll. The
deflection compensation roll includes a crosspiece, roll bearings
composed of radial bearings and at least one hydrostatic bearing
arrangement, and a roll jacket, which is rotatably supported on the
crosspiece by the roll bearings. The at least one hydrostatic
bearing arrangement acts in the axial direction. The process
includes positioning radial roll bearings each bearing end of the
deflection compensation roll and between the crosspiece and the
roll jacket, wherein the radial roll bearings absorb radial forces,
and positioning at least one hydrostatic bearing arrangement
between the crosspiece and the roll jacket, wherein the at least
one hydrostatic bearing arrangement absorbs axial forces.
Inventors: |
VAN HAAG, ROLF; (KERKEN,
DE) ; WENZEL, REINHARD; (KREFELD, DE) |
Correspondence
Address: |
GREENBLUM & BERNSTEIN, P.L.C.
1941 ROLAND CLARKE PLACE
RESTON
VA
20191
US
|
Assignee: |
Neil F. Greenblum
|
Family ID: |
7868084 |
Appl. No.: |
09/306851 |
Filed: |
May 7, 1999 |
Current U.S.
Class: |
384/101 ;
384/121 |
Current CPC
Class: |
F16C 13/028 20130101;
D21G 1/0226 20130101; D21G 1/0213 20130101 |
Class at
Publication: |
384/101 ;
384/121 |
International
Class: |
F16C 019/00; F16C
021/00; F16C 032/06 |
Foreign Application Data
Date |
Code |
Application Number |
May 16, 1998 |
DE |
198 22 145.2 |
Claims
What is claimed:
1. A deflection adjustment roll comprising: a crosspiece; roll
bearings composed of radial bearings and at least one hydrostatic
bearing arrangement; and a roll jacket, which is rotatably
supported on the crosspiece by the roll bearings, wherein the at
least one hydrostatic bearing arrangement acts in the axial
direction.
2. The roll according to claim 1, the hydrostatic bearing
arrangement comprising: a piston-cylinder arrangement; a support
shoe, which is fixed in the axial direction relative to the
crosspiece; a first axially oriented support surface being adapted
for coupling to the piston-cylinder arrangement; and a second
axially oriented support surface oppositely oriented with respect
to the first axially oriented support surface being adapted for
coupled with the support shoe.
3. The roll according to claim 2, the piston-cylinder arrangement
comprising a ring piston arranged to surround the crosspiece.
4. The roll according to claim 2, further comprising a pressure
source; and the piston and the support shoe having bearing pockets
connected to the pressures source.
5. The roll according to claim 2, wherein the first and second
support surfaces are coupled to the roll jacket, and wherein the
piston-cylinder arrangement and the support shoe are coupled to the
crosspiece.
6. The roll according to claim 2, at least one of the support shoe
and the piston-cylinder arrangement being tiltably mounted relative
to the crosspiece.
7. The roll according to claim 1, the hydrostatic bearing
arrangement comprising a disk, wherein the disk is composed of two
axial sides adapted to exerted upon with a pressure.
8. The roll according to claim 1, further comprising: a piston; a
support shoe; the roll jacket comprising a first and a second
bearing end; the hydrostatic bearing arrangement comprising a first
annular disk positioned at the first bearing end and a second
annular disk positioned at the second bearing end; the piston being
positioned to act on the first annular disk; and the support shoe
being positioned to act on the second annular disk.
9. The roll according to claim 8, wherein the piston and support
shoe are positioned to act on axially outer surfaces of the first
and second annular disks, respectively.
10. The roll according to claim 9, wherein the first and second
annular disks are positioned to form an axial seal with a
respective one of the piston and the support shoe.
11. The roll according to claim 8, the at least one hydrostatic
bearing arrangement comprising a plurality of hydrostatic bearing
arrangements, wherein the plurality of hydrostatic bearing
arrangements are positioned axially inside of the radial roll
bearings.
12. The roll according to claim 8, the at least one hydrostatic
bearing arrangement comprising a plurality of hydrostatic bearing
arrangements, one of the plurality of hydrostatic bearing
arrangements comprising a first and second bearing element; the
first and second bearing elements being slidably coupled along a
plane oblique to axial direction.
13. The roll according to claim 8, the at least one hydrostatic
bearing arrangement comprising a plurality of hydrostatic bearing
arrangements, the plurality of hydrostatic bearing arrangements
being coupled to the crosspiece.
14. The roll according to claim 8, further comprising a bearing
ring postionable over the crosspiece; the at least one hydrostatic
bearing arrangement comprising a plurality of hydrostatic bearing
arrangements; and the plurality of hydrostatic bearing arrangements
being coupled to the bearing ring.
15. The roll according to claim 1, wherein the at least one
hydrostatic bearing arrangement is positioned axially between the
radial roll bearings.
16. The roll according to claim 1, wherein the at least one
hydrostatic bearing arrangement is coupled to the crosspiece.
17. The roll according to claim 1, further comprising a bearing
ring postionable over the crosspiece; and the at least one
hydrostatic bearing arrangement being coupled to the bearing
ring.
18. A process for treating a web in an apparatus that includes the
deflection compensation roll according to claim 1, the process
comprising: forming a nip between the deflection compensation roll
and a counter roll; and guiding the web through the nip.
19. The process according to claim 18, further comprising: loading
the deflection compensation roll by pressing the roll jacket in a
direction away from the crosspiece.
20. The process according to claim 19, further comprising:
absorbing axial forces on the roll jacket with the at least one
hydrostatic bearing arrangement.
21. A process for rotatably supporting a roll jacket on a
crosspiece that extends through the roll jacket in a deflection
adjustment roll, the process comprising: positioning radial roll
bearings at each bearing end of the deflection adjustment roll and
between the crosspiece and the roll jacket, wherein the radial roll
bearings absorb radial forces; and positioning at least one
hydrostatic bearing arrangement between the crosspiece and the roll
jacket, wherein the at least one hydrostatic bearing arrangement
absorbs axial forces.
22. The process according to claim 21, wherein the at least one
hydrostatic bearing arrangement comprises a piston-cylinder
arrangement, a support shoe that is fixed in the axial direction
relative to the crosspiece, a first axially oriented support
surface, and a second axially oriented support surface oppositely
oriented with respect to the first axially oriented support
surface, the process further comprising: biasing the piston of the
piston-cylinder arrangement toward the first axially oriented
support surface; and positioning the support shoe opposite the
second axially oriented support surface.
23. The process according to claim 22, further comprising: coupling
the first and second support surfaces to the roll jacket; and
coupling the piston-cylinder arrangement and the support shoe to
the crosspiece.
24. The process according to claim 21, wherein the deflection
compensation roll comprises a piston, a support shoe, the
hydrostatic bearing arrangement including a first annular disk
positioned at a first bearing end of the deflection compensation
roll and a second annular disk positioned at a second bearing end
of the deflection compensation roll, the process further
comprising: positioning the piston to act on the first annular
disk; and positioning the support shoe to act on the second annular
disk.
25. The process according to claim 24, further comprising
positioning the piston and support shoe to act on axially outer
surfaces of the first and second annular disks, respectively.
26. The process according to claim 25, further comprising
positioning the first and second annular disks to form an axial
seal with a respective one of the piston and the support shoe.
27. The process according to claim 21, wherein the at least one
hydrostatic bearing arrangement includes a plurality of hydrostatic
bearing arrangements, and the process further comprises:
positioning the plurality of hydrostatic bearing arrangements
axially inside of the radial roll bearings.
28. The process according to claim 21, wherein the at least one
hydrostatic bearing arrangement includes a plurality of hydrostatic
bearing arrangements, the process further comprising: coupling the
plurality of hydrostatic bearing arrangements to the
crosspiece.
29. The process according to claim 21, wherein the deflection
compensation roll comprises a bearing ring postionable over the
crosspiece and the at least one hydrostatic bearing arrangement
comprises a plurality of hydrostatic bearing arrangements, the
process further comprising: coupling the plurality of hydrostatic
bearing arrangements to the bearing ring.
30. The process according to claim 21, further comprising:
positioning the at least one hydrostatic bearing arrangement
axially between the radial roll bearings.
31. The process according to claim 21, the process further
comprising: coupling the at least one hydrostatic bearing
arrangement to the crosspiece.
32. The process according to claim 21, wherein the deflection
compensation roll comprises a bearing ring postionable over the
crosspiece, and the process further comprises: coupling the at
least one hydrostatic bearing arrangement to the bearing ring.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority under 35 U.S.C.
.sctn. 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
[0002] 1. Field of the Invention
[0003] 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.
[0004] 2. Discussion of Background Information
[0005] 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.
[0006] 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 roll bearings.
[0007] For this reason, a spherical roll 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.
[0008] The types of bearings available are limited since it is
necessary, in a roll bearing, to equip one end with a fixed bearing
and the other end with a movable bearing.
SUMMARY OF THE INVENTION
[0009] The present invention relates to a roll bearing for use in a
roll and to other type bearings.
[0010] 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 bearings and a
hydrostatic bearing arrangement that acts in the axial
direction.
[0011] 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 roll 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 roll bearings having convex, oblong rolling
elements between an inside ring and an outside ring. In this
manner, the profile radius is substantially larger than that of
barrel-shaped roll bearings or spherical roll 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.
[0012] 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.
[0013] 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.
[0014] 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.
[0015] 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.
[0016] 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 roll bearing, which is adjacent to the
hydrostatic bearing arrangement, is the fixed bearing. The other
bearing is the movable bearing.
[0017] 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.
[0018] 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.
[0019] 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 jacket
is to be placed under hydraulic pressure. A seal between the
annular disks and the roll jacket can be achieved in a relatively
problem free manner. The same is true for a seal between either the
support shoe or the piston-cylinder arrangement and the crosspiece.
Since the hydrostatic pressure of the bearing pockets is present on
the contact surfaces, the seal between the moving surfaces, i.e.,
between one annular disk and the support shoe and between the
piston-cylinder arrangement and the other support disk, can be
managed relatively well since. While this arrangement may result in
certain leakage of the hydraulic fluid radially outwardly, no
pressure escapes from the interior of the roll jacket.
[0020] Advantageously, the support shoe and/or the piston-cylinder
arrangement may be tiltable relative to the crosspiece. Thus, it
may be ensured that despite a certain deflection or sagging of the
crosspiece, it is always possible to obtain plane-parallel contact
of the support shoe or piston-cylinder arrangement with the annular
disks or disk. Such a tiltable mounting may be achieved, e.g., in
that the support shoe is supported in an axially oriented spherical
cap, or permits the piston to assume somewhat of an angle relative
to the cylinder.
[0021] The present invention is directed to a deflection adjustment
roll that includes a crosspiece, roll bearings composed of radial
bearings and at least one hydrostatic bearing arrangement, and a
roll jacket, which is rotatably supported on the crosspiece by the
roll bearings. The at least one hydrostatic bearing arrangement
acts in the axial direction.
[0022] In accordance with another feature of the present invention,
the hydrostatic bearing arrangement may include a piston-cylinder
arrangement, a support shoe, which is fixed in the axial direction
relative to the crosspiece, a first axially oriented support
surface being adapted for coupling to the piston-cylinder
arrangement, and a second axially oriented support surface
oppositely oriented with respect to the first axially oriented
support surface being adapted for coupling with the support shoe.
Moreover, the piston-cylinder arrangement may include a ring piston
arranged to surround the crosspiece. Further, a pressure source may
be provided, and the piston and the support shoe may have bearing
pockets connected to the pressures source. Further still, the first
and second support surfaces are coupled to the roll jacket. The
piston-cylinder arrangement and the support shoe may be coupled to
the crosspiece. Still further, at least one of the support shoe and
the piston-cylinder arrangement are tiltably mounted relative to
the crosspiece.
[0023] According to still another feature of the present invention,
the hydrostatic bearing arrangement may include a disk. The disk
may be composed of two axial sides adapted to exerted upon with a
pressure.
[0024] According to a further feature of the present invention, a
piston and a support shoe may be provided. The roll jacket includes
a first and a second bearing end, the hydrostatic bearing
arrangement includes a first annular disk positioned at the first
bearing end and a second annular disk positioned at the second
bearing end, the piston is positioned to act on the first annular
disk, and the support shoe is positioned to act on the second
annular disk.
[0025] In accordance with a still further feature of the present
invention, the piston and support shoe are positioned to act on
axially outer surfaces of the first and second annular disks,
respectively. Further, the first and second annular disks may be
positioned to form an axial seal with a respective one of the
piston and the support shoe.
[0026] According to yet another feature of the present invention,
the at least one hydrostatic bearing arrangement includes a
plurality of hydrostatic bearing arrangements. The plurality of
hydrostatic bearing arrangements may be positioned axially inside
of the radial roll bearings. Still further, the at least one
hydrostatic bearing arrangement includes a plurality of hydrostatic
bearing arrangements, one of the plurality of hydrostatic bearing
arrangements includes a first and second bearing element, and the
first and second bearing elements are slidably coupled along a
plane oblique to axial direction. Further still, the at least one
hydrostatic bearing arrangement includes a plurality of hydrostatic
bearing arrangements, and the plurality of hydrostatic bearing
arrangements are coupled to the crosspiece. Further, a bearing ring
is postionable over the crosspiece, the at least one hydrostatic
bearing arrangement includes a plurality of hydrostatic bearing
arrangements, and the plurality of hydrostatic bearing arrangements
are coupled to the bearing ring.
[0027] According to another feature of the present invention, the
at least one hydrostatic bearing arrangement is positioned axially
between the radial roll bearings.
[0028] According to still another feature of the present invention,
the at least one hydrostatic bearing arrangement is coupled to the
crosspiece.
[0029] In accordance with still another feature of the present
invention, a bearing ring may be postionable over the crosspiece,
and the at least one hydrostatic bearing arrangement may be coupled
to the bearing ring.
[0030] According to yet another feature of the present invention,
the present invention is directed to a process for treating a web
in an apparatus that includes the deflection compensation roll. The
process includes forming a nip between the deflection compensation
roll and a counter roll, and guiding the web through the nip.
Further, the process may include loading the deflection
compensation roll by pressing the roll jacket in a direction away
from the crosspiece. Moreover, the process may include absorbing
axial forces on the roll jacket with the at least one hydrostatic
bearing arrangement.
[0031] The present invention is directed to a process for rotatably
supporting a roll jacket on a crosspiece that extends through the
roll jacket in a deflection compensation roll. The process includes
positioning radial roll bearings at each bearing end of the
deflection compensation roll and between the crosspiece and the
roll jacket, wherein the radial roll bearings absorb radial forces,
and positioning at least one hydrostatic bearing arrangement
between the crosspiece and the roll jacket, wherein the at least
one hydrostatic bearing arrangement absorbs axial forces.
[0032] In accordance with another feature of the present invention,
the at least one hydrostatic bearing arrangement includes a
piston-cylinder arrangement, a support shoe that is fixed in the
axial direction relative to the crosspiece, a first axially
oriented support surface, and a second axially oriented support
surface oppositely oriented with respect to the first axially
oriented support surface. The process further includes biasing the
piston of the piston-cylinder arrangement toward the first axially
oriented support surface, and positioning the support shoe opposite
the second axially oriented support surface. Moreover, the process
further includes coupling the first and second support surfaces to
the roll jacket, and coupling the piston-cylinder arrangement and
the support shoe to the crosspiece.
[0033] According to still another feature of the present invention,
the deflection compensation roll may include a piston, a support
shoe, the hydrostatic bearing arrangement including a first annular
disk positioned at a first bearing end of the deflection
compensation roll and a second annular disk positioned at a second
bearing end of the deflection compensation roll. The process may
further include positioning the piston to act on the first annular
disk, and positioning the support shoe to act on the second annular
disk. Further, the process may include positioning the piston and
support shoe to act on axially outer surfaces of the first and
second annular disks, respectively. Still further, the process may
include positioning the first and second annular disks to form an
axial seal with a respective one of the piston and the support
shoe.
[0034] According to a still further feature of the present
invention, the at least one hydrostatic bearing arrangement may
include a plurality of hydrostatic bearing arrangements, and the
process may further include positioning the plurality of
hydrostatic bearing arrangements axially inside of the radial roll
bearings.
[0035] In accordance with another feature of the present invention,
the at least one hydrostatic bearing arrangement may include a
plurality of hydrostatic bearing arrangements, the process may
further include coupling the plurality of hydrostatic bearing
arrangements to the crosspiece.
[0036] In accordance with still another feature of the present
invention, the deflection compensation roll includes a bearing ring
postionable over the crosspiece and the at least one hydrostatic
bearing arrangement comprising a plurality of hydrostatic bearing
arrangements, and the process may further include coupling the
plurality of hydrostatic bearing arrangements to the bearing
ring.
[0037] According to a further feature of the present invention, the
process may further include positioning the at least one
hydrostatic bearing arrangement axially between the radial roll
bearings.
[0038] According to still another feature of the present invention,
the process may further include coupling the at least one
hydrostatic bearing arrangement to the crosspiece.
[0039] In accordance with yet another feature of the present
invention, the deflection compensation roll may include a bearing
ring postionable over the crosspiece, and the process may further
include coupling the at least one hydrostatic bearing arrangement
to the bearing ring.
[0040] Other exemplary embodiments and advantages of the present
invention may be ascertained by reviewing the present disclosure
and the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] The present invention is further described in the detailed
description which follows, in reference to the noted plurality of
drawings by way of non-limiting examples of exemplary embodiments
of the present invention, in which like reference numerals
represent similar parts throughout the several views of the
drawings, and wherein:
[0042] FIGS. 1 and 1A illustrate a first embodiment of a deflection
compensation roll, and an enlarged detail of a hydrostatic bearing
arrangement;
[0043] FIGS. 2 and 2A illustrate an enlarged detail of a second
embodiment of the deflection compensation roll, and an enlarged
detail of a hydrostatic bearing arrangement;
[0044] FIG. 3 illustrates a third embodiment of the deflection
compensation roll having a jacket lift; and
[0045] FIGS. 4 and 4A illustrate an enlarged detail of a fourth
embodiment of the deflection compensation roll having jacket lift,
and an enlarged detail of a hydrostatic bearing arrangement.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0046] The particulars shown herein are by way of example and for
purposes of illustrative discussion of the embodiments of the
present invention only and are presented in the cause of providing
what is believed to be the most useful and readily understood
description of the principles and conceptual aspects of the present
invention. In this regard, no attempt is made to show structural
details of the present invention in more detail than is necessary
for the fundamental understanding of the present invention, the
description taken with the drawings making apparent to those
skilled in the art how the several forms of the present invention
may be embodied in practice.
[0047] FIGS. 1 and 2 schematically depict a longitudinal section of
one-half of a deflection compensation (sag adjustment) roll 1
having a roll jacket 2, which is rotatably mounted on a reversible
crosspiece 5 by roll bearings 3 and 4.
[0048] Support elements 6, which may be, e.g., hydrostatic support
elements, are positioned between roll jacket 2 and crosspiece 5.
When roll jacket 2 is loaded during operation, e.g., during glazing
of a paper web, roll jacket 2 tends to sag due to the loading.
However, as is known in the art, this sagging or deflection can be
counteracted or compensated for using support elements 6. In this
manner, a force is introduced into crosspiece 5, which,
accordingly, somewhat sags or is deflected.
[0049] In practice, roll bearings 3 and 4 can absorb only radial
forces, and they include convex rolls 7 positioned between an
inside separator 8 and an outside separator 9. The rolls are
relatively long. A race radius of an inside ring and an outside
ring is substantially larger than the race radius of conventional
spherical roll bearings. Roll bearings 3 and 4 are available, e.g.,
under the name "CARB" from the company SKF, and, like normal
spherical roll bearings, roll bearings 3 and 4 can compensate for
misalignment and absorb radial loads. Moreover, roll bearings 3 and
4 can compensate for radial displacements of roll jacket 2 relative
to crosspiece 5 like a cylinder roll bearing. Thus, roll bearings 3
and 4 have a relatively high angular mobility and a relatively high
axial adjustability. However, in practice, these roll bearings 3
and 4 cannot absorb axial forces.
[0050] Accordingly, the axial mounting of roll jacket 2 relative to
crosspiece 5 is provided by a hydrostatic bearing arrangement 10.
As shown in greater detail in FIG. 1A, bearing arrangement 10
includes a disk 11, which is fixedly coupled or connected, in both
the axial and rotational directions, with roll jacket 2. A
piston-cylinder arrangement, which includes a piston 12 and a
cylinder 13, is coupled or attached axially to crosspiece 5. Piston
12 may be, e.g., a ring piston, and it may be sealingly mounted in
cylinder 13 and movable in the axial direction. Cylinder 13 may be
arranged within a housing 14. Piston 12 may be pre-loaded in a
direction toward disk 11 using, e.g., a spring 24 positioned
between piston 12 and housing 14 to adjust a gap between disk 11
and piston 12. With a proper design, the spring force sets an
optimum gap size. With its end, piston 12 contacts a support
surface 15 of disk 11. A radial projection 17 of housing 14 may
contact an axially opposing support surface 16 of disk 11.
Accordingly, disk 11 may be gripped in tong-like fashion by piston
12 and projection 17 of housing 14. Bearing pockets 18 and 19,
which can be supplied with hydraulic fluid via a line 20, may be
arranged in the surfaces of piston 12 and projection 17 to contact
support surfaces 15 and 16. Line 20 may also supply hydraulic fluid
to cylinder 13. Throttles (not depicted in detail) may be
positioned between line 20 and bearing pockets 18 and 19. Thus,
bearing arrangement 10 acts as a hydrostatic bearing. The hydraulic
fluid introduced through line 20 flows out through a gap between
piston 12 and support surface 15 or through a gap between
projection 17 and support surface 16. In this manner, an
equilibrium is produced such that disk 11 has a distance maintained
between its support surfaces 15 and 16 and piston 12 and projection
17, respectively. This distance may be maintained as small as
possible due to the pressure prevailing in cylinder 13, but a
distance is provided. In this manner, wear is kept low by
hydrostatic lubrication.
[0051] Housing 14 may be non-rotatably and immovably (fixedly)
positioned in the axial direction on crosspiece 5. Housing 14 may
also include a convexly arranged bearing surface 21 which is
bounded by two O-rings 22, 23, such that a slight tilting movement
of housing 14 relative to crosspiece 5 is possible. In this manner,
it may be ensured that even with sagging or deflection of
crosspiece 5 there will always be plane-parallel contact of the end
surface of piston 12 or the end surface of projection 17 on support
surfaces 15 and 16 of disk 11.
[0052] In the exemplary embodiment, roll bearing 3, which is
arranged in the vicinity of bearing arrangement 10, forms a fixed
bearing. Accordingly, roll bearing 4 may be the movable bearing. In
accordance with this arrangement, axial movement between crosspiece
5 and roll jacket 2 is permitted.
[0053] FIG. 2 depicts another embodiment of a roll 1, in which the
same elements are provided with the same reference numerals.
[0054] Roll bearing 3 may be arranged in the region of the fixed
bearing, while roll bearing 4 may form the movable bearing.
[0055] In this embodiment, the hydrostatic bearing arrangement may
include two parts relatively distant from each other, e.g., a
support arrangement 31 may be located axially inside and near roll
bearing 3 and a piston-cylinder arrangement 32 may be located
axially inside and near roll bearing 4. Roll bearings 3 and 4 are
formed as discussed in the embodiment shown in FIG. 1.
[0056] Support shoe arrangement 31 may include a spherical
cap-shaped base 33, which is stationarily or fixedly disposed both
axially and rotationally on crosspiece 5. Base 33 supports a
support shoe 34, which has an end, e.g., a right end when viewed in
the axial direction, that includes a hydrostatic bearing pocket 35.
The end of support shoe 34 with hydrostatic bearing pocket 35 may
be positioned to contact a support surface 36 of an annular disk
37, which is coupled or connected non-rotatably and stationarily in
the axial direction to roll jacket 2.
[0057] Piston-cylinder arrangement 32, shown in greater detail in
FIG. 2A, may include a housing 38, which is arranged non-rotatably
and stationarily in the axial direction on crosspiece 5. A cylinder
39 is provided in housing 38 so that a piston 40, which may be,
e.g., a ring piston, can move in the axial direction. Piston 40 has
an end, e.g., a left end when viewed in the axial direction, that
includes a hydrostatic bearing pocket 41, which is connected
fixedly in the axial direction to roll jacket 2. A spring 45 may be
positioned between housing 38 and piston 40.
[0058] Thus, piston-cylinder arrangement 32 and support shoe
arrangement 31 are arranged to grip annular disks 37 and 43 in a
tong-like manner.
[0059] Cylinder 39 may be placed under pressure using hydraulic
fluid, which is supplied through a line 44. Piston 40 may have a
connection line between pressure pocket 41 and cylinder 39, such
that bearing pocket 41 is provided with pressure via the hydraulic
fluid. Line 44 may also supply bearing pocket 35 in support shoe
34.
[0060] As with the embodiment depicted in FIG. 1, piston 40 must
have relatively high axial mobility in cylinder 39 since it must be
able to compensate for the entire longitudinal change of roll
jacket 2.
[0061] Hydrostatic bearing arrangement 31 and 32 may also be
utilized in this embodiment to seal interior 46 of roll jacket 2
axially outwardly.
[0062] In this manner, support shoe 34 may be attached via sealing
rings 47, and housing 38 may be attached via sealing ring 48 to
crosspiece 5. These sealing rings will not, in most cases, be able
to completely prevent hydraulic fluid from leaking out of interior
46. However, they will sufficiently prevent pressure loss in
interior 46. Thus, an escape of pressure between contact surfaces
35 and 36 of support shoe 34 and annular disk 37, respectively, or
piston 40 and support surface 42 of annular disk 43 is not possible
because the pressure in bearing pockets 41 prevents the same.
[0063] Because of the spherical cap-shaped bearing surface of the
base 33 and the correspondingly adapted bearing surface of support
shoe 34, tiltability of support shoe 34 relative to crosspiece 5 is
provided on this side of hydrostatic bearing arrangement 31, such
that crosspiece 5 can sag somewhat, without sacrificing the
plane-parallel alignment of the surfaces with the hydrostatic
bearing pocket 35 on support surface 36 of annular disk 37.
[0064] In the region of piston-cylinder arrangement 32, parallel
alignment may be retained in that piston 40 can be positioned at
somewhat of an angle within cylinder 39.
[0065] In the embodiments of FIGS. 1 and 2, roll jacket 2 is
centered relative to crosspiece 5. Such rolls are commonly referred
to as "C-type" rolls, and the roll bearings 3 and 4 are attached
directly to crosspiece 5.
[0066] Hydrostatic axial bearings 10, 31, and/or 32 can also be
utilized in rolls having jacket lift, i.e., commonly referred to as
"F-type" rolls, as schematically depicted in FIGS. 3 and 4. It is
noted that the embodiment shown in FIG. 3 corresponds largely to
that depicted in FIG. 1, and that the embodiment shown in FIG. 4
corresponds largely to that depicted in FIG. 2.
[0067] In the embodiment illustrated in FIG. 3, roll bearings 3 and
4 and hydrostatic bearing arrangement 10 are no longer attached
directly to crosspiece 5. Rather, these elements are coupled to a
bearing ring 25 that surrounds crosspiece 5. In a known manner,
crosspiece 5 may be flattened parallel to the direction of
displacement on the axial positions where the bearing ring or
carrier 25 is located. Accordingly, bearing ring 25 may include
flat guide surfaces such that it can be shifted up and down, based
on the depiction in FIG. 3. When bearing ring 25 can be inclined
relative to crosspiece 5, which will often be the case, then it is
possible to do without the convex shape of housing 14 and to
dispose housing 14 directly on bearing ring 25.
[0068] Similarly, it is possible to arrange hydrostatic bearing
arrangement 32, as well as roll bearings 3 and 4, not only directly
on crosspiece 5, as depicted in FIG. 2, but also on a bearing ring
or carrier 50, which, as shown in greater detail in FIG. 4A, can be
displaced upwardly and downwardly relative to crosspiece 5.
[0069] With the displacement of bearing ring 25 or 50, roll jacket
2 as a whole may be raised or lowered relative to crosspiece 5,
under the action of support elements 6.
[0070] It is noted that the foregoing examples have been provided
merely for the purpose of explanation and are in no way to be
construed as limiting of the present invention. While the present
invention has been described with reference to an exemplary
embodiment, it is understood that the words which have been used
herein are words of description and illustration, rather than words
of limitation. Changes may be made, within the purview of the
appended claims, as presently stated and as amended, without
departing from the scope and spirit of the present invention in its
aspects. Although the present invention has been described herein
with reference to particular means, materials and embodiments, the
present invention is not intended to be limited to the particulars
disclosed herein; rather, the present invention extends to all
functionally equivalent structures, methods and uses, such as are
within the scope of the appended claims.
* * * * *