Note: Descriptions are shown in the official language in which they were submitted.
BACKGROI)ND OF THE INVENTION
This invention relates to a controlled deflection roll,
and more particularly to a roll comprising an inner shaft and
an outer shell which is attached to the shaft at its middle or
near it and where the deflection of the outer shell caused by
the load acting on the roll is partly or entirely eliminated by
means of adjustable supporting forces acting upon the ends of
the shell.
As an example of a roll of that kind the structure dis-
20 closed in the CA Patent 920,406 can be mentioned. The supporting
forces in a roll of this kind can be achieved for instanc~ by
excenter means or by using hydraulic load devices. The excenter
means are however very complicated. In the hydraulic load
device of the prior art there are several seals between moving
stationary parts where oil leakage and friction losses accrue.
In either case it is very difficult to adjust the direction of
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the supporting forces while the roll is in operation.
Controlled deflection rolls are used for instance
as press rolls in paper machine6 and as supporting rolls
in slitter rewinders. In particular in the latter
application where the rotative velocity of the roll
is high and fluctuating, harmful vibrations often occur
in the devices according to the prior art. Furthermore
it is desirable that the direction of the supporting
force should be adjustable while the diameter of the
reel of paper increase. ~ -
The main object of the present invention is to
provide a controlled deflection roll, wherein the direction
and the size of the supporting forces acting upon the
ends of the roll shell can easily be adjusted and which
has no tendency to vibrate.
In general terms, the presen~ invention provides,
in a controlled deflection roll apparatus having a
stationary base means, an inner shaft supported by
said base means for rotation relative thereto, an outer
roll shell attached to the shaft at a central lengthwise
portion thereof for support thereby and rotation therewith,
and fluid pressure operated jack means operable to exert
supporting forces on the roll shell at the ends thereof
to control the deflection of the roll shell by load
forces acting thereon, the i~mprovement which comprises:
a bearing having a stationary part and having a rotary
part connected to said roll shell for rotation therewith,
and said jack means having a plurality of reaction
- elements aligned along respective radial paths and
; 30 responsive to the influence of fluid pressure to generate
; forces directed along said respective paths and applied
to the stationary part of said bearing and transmitted
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through the rotary part thereof to the roll shell to
control the deflection thereof by said load forces, said
radial paths being generally stationary with respect to
said reaction elements accommodating the adjustment of
the fluid pressure influencing respective reaction
elements for corres~Onding adjustment of said generated
forces.
Preferably, the jack means includes a support
member having a plurality of passages each extending along
a corresponding one of said radial paths and each
receiving a corresponding reaction element.
DESCRIPTION OF THE DRAWINGS :
Specific examples of the present invention are
illustrated by the accompanying drawings in which:
Fig. 1 is an axial sectional view of a roll shell
supporting device built in accordance with the invention,
Fig. 2 is a cross section taken on the line A-A
of Fi~. 1,
Fig. 3 shows a detail of the device,
Fig. 4 shows another embodl~ent of the inventlon
in an axial sectional view, and
Fig. 5 is a cross section taken on the line B-B
of Fig. 4.
The roll which is partly shown in Fig. 1 comprises -
an outer shell 1 which is attached to the rotating inner
shaft 2 at its middle or near it for instance in a manner
disclosed in the CA
-
:
A - 2a -
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Pat. appl. 218 783. The inner shaft consists of tubular shaft
elements 3, end discs 4 and journal ends 5. To the roll shell
are fastened end plates 7 provided wi~h hubs 6 in which the
inner ring of a bearing 8 is mounted. The outer ring of bearing
8 is mounted inside the pressure ring 9 of the supporting device.
In the pressure ring there is a plurality of radial borings 10,
preferably space~ at equal angles from each other. Balls 11 are
disposed within the borings.
As shown in Fig. 2, hydraulic fluid under pressure can
be directed to the space 12 under the balls through the borings 13
and 14 which are connected to a pump 16 through lines 15. The
space under each ball is connected through a separate line and
a separate pressure reducing valve 17 to the feed line 18. Ad-
ditionally there are valves 19 which permit the oil to flow
freely to the spaces under the balls, but restrict the flow in
the opposite direction. The balls are arranged to contact a
surrounding support ring 20, which is attached to the bearing
22, rotably supporting the journal end 5. The pressure ring 9
is connected to the bearing pedestal 21 by means of a flexible
pin 23 as shown in Fig. 3.
The clearance between the balls 11 and the borings 10 is
such that the balls can move easily in the borings but the oil
leakage is as small as possible. The leakage oil is removed
through the boring 24 and the line 25 shown in Figs 1 and 2.
When hydraulic fluid under pressure is directed to the
apace under the balls, the balls function as pistons and generate
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radial forces between the ~-upport ring 20 and the pressure ring
9. If the balls are of equal size and equally spaced in the
pressure ring, the resulting force is zero when the pressure
applied on each ball is the same. If the pressure exerted against
the balls are adjusted to be unequal, a force is generated which
strives to move the pressure ring in relation to the support
ring, i.e. a force bending the roll shell is generated. In this
manner a bending moment of any desired size and direction can
be achieved, by means of which, the deflection of the roll shell
caused by a load acting on the roll can be partly or entirely
eliminated. The supporting force caused by the hydraulic pres-
sure is transmitted to the roll shell through the bearing 8.
m e pressure ring is prevented to ~otate as shown in Fig. 3.
If the roll ~shell tends to vibrate, each ball and the
hydraulic system behind it functions as a shock absorber, be-
` cause the oil which flows out from the space under the balls, when
each ball is forced into its boring, flows through a restriction
in the valves 19. Because the balls are located on all sides of
the pressure ring an efficient dampening of the vibrations in
all directions is achieved.
- In the embodiment shown in Fig. 4 the tubular inner shaft
26 is rotably supported in bearings 28 mounted in the end discs
27. The roll shell 29 which is attached to the inner shaft in -- -
its middle or near it, is rotably supported in bearings 31 -
mounted in the end discs 30. The support ring 32, which forms
- the inner ring of the bearing, surrounds the pressure plug 33
.
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provided with a plurality of radial borings, in which the balls
35 can move. The spaces 36 under the balls are connected to a
hydraulic pressure source through the borings 37 and 38. The
support ring is held against rotation. The inner shaft is
rotably supported by a bearing 28 mounted on the end of pres-
sure plug 33, which is rigidly attached to a support pedestal
39.
The function of the embodiment shown in Fig. 4 can -
easily be understood from the description of the embodiment in ~ -
10- Fig. 1 and 2. It is suited for rolls which do not need to be con-
nected to drive means as for instance paper guide rolls and felt
guide rolls in paper machines.
The balls which are used as pistons are balls of the
type used for ordinary ball bearings and as such can be easily ob-
tained at a moderate price. Because of the fact that the balls
are only in contact with nonrotating surfaces which hardly more
at all in relation to them, the wear of the balls in negligible.
m e supporting force is transmitted to the rotating parts through
rolling bearings which are lubricated by leakage oil. ~-
~n order to achieve dampening of the vibration and
adjustment of the supporting forces in all directions, there must
be at least three radial borings, at equal angles to each other in
which balls movable by hydraulic pressure are disposed in the
' pressure means (9,33).
In order to achieve a dampening effect in all directions
a pressure must be maintained under each ball. This also guaran-
tees that the balls will be lubricated. An oil of high viscosity
should be used in order to minimize the oil leakage.
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From the foregoing description of two preferred :
embodiments of the invention, the artisan will appreciate
that the invention basically is directed to an improvement
in a controlled deflection roll apparatus having a
stationary base means 21, an inner shaft 2, 26 supported
by such base means for rotation relative thereto, an
outer roll shell 1, 29 attached to the inner shaft at a
central lengthwise portion thereof for support thereby
and rotation therewith, and fluid pressure operated jack
means operable to exert supporting forces on the roll
shell at the ends thereof to control the deflection of
the roll shell by load forces acting thereon.
Generally, improvement of the invention can be
considered as a bearing 8, 31 and 32, having a stationary
part 32, and having a rotary part connected to the roll
shell for rotation therewith, and a certain combination -
of features in the jack means. For the embodiment of
invention represented by Figs. 1 and 2, the jack means
can be considered as the combination of the pressure ring
9, radial borings 10, balls 11, under-ball spaces 12,
borings 13 and 14 line 15 and support ring 20, and
optionally the auxialiary equipment including the pump 16,
reducing valves 17, feedline 18, check valves 19, leakage
collection boring 24 and drain line 25.
For the embodiment of invention represented by
Figs. 4 and 5, the jack means has counterpart elements
that may be considered as the co~bination of support ring
32, pressure plug 33, radial borings 34, balls 35, under-
balls spaces 36, borings 37 and 38, and typical fluid
pressure supply and regulating equipment, such as is
exemplified by Fig. 2 and connected with borings 38. ~ -
In both embodiments, the jack means has a plurality
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of reaction elements expediently in the form of balls ll
or 35 aligned along respective radial paths defined by
the axis of respective radial borings 10, 34, and these
reaction elements are responsive to the influence of
fluid pressure in the under-balls spaces 12, 36, to generate
forces directed along such respective radial paths. These
forces are applied to the stationary part of the bearing
8, or in the case of the Figs. 4 and 5 embodiment, to the
ring 32, and are transmitted through the rotary part of
the bearing to the roll shell to control the deflection
thereof by the load forces. The radial paths along which
the forces generated by the reaction elements act are
generally stationary with respect to the base means 21,
which means that there is very little wear on the reaction
element balls ll, 35. Also, there is no need to provide
for the transmission of pressurized fluid to any rotating
parts, since the ring 9 of Figs. 1 and 2 and the plug 33
of Figs. 4 and 5, which in both instances receive the
reaction elements, are stationary.
For better control of the force applied to the
roll shell to counteract the load forcedeflection thereof,
the jack means has fluid flow paths 13, 14 and 15 and 37,
38 to the reaction elements accommodating the adjustment
of the fluid pressure influencing respective reaction
elements 11, 35 for corresponding adjustment of the
generated forces.
