Note: Descriptions are shown in the official language in which they were submitted.
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The invention relates to a device for protecting
rolling-mill or the like bearin~s from overloading. Especially
roller-briquette-presses having a driven and a idler roll.
It is known that the rolls in rolling mills, especially
roller-briquette-presses, are subjected during operation to con-
siderable thermal stressing, leading to changes in the length
of the roll. These thrust forces, acting in the axial direction
of the rolls must be absorbed by the roll-bearings, and must
be compensated for by movement of the outer rings in the bearing
housing. The resulting additional load on the bearings frequently
reduces the life thereof by up to about 50%. Furthermore, the
high bearing loads, occurring more particularly during the
operation of roller-briquette-presses, make it necessary to use
self-aligning bearings with undivided cages which, as compared
with roll-bearings with divided cage-housings, are less able to
withstand axial thrust.
~- It is the purpose of the present invention to provide
a device which reliably eliminates overloading of rolling-mill
bearings by axial thrust forces arising while the rolls are in
operation. This purpose is achieved in that one of the two
bearing housings of the roll is adapted to yield in the axial
direction. As a result of this axial yielding o-f one of the two
bearing housings, it is possible to compensate for all axial
thrust forces, arising while the rolling-mill is in operation,
by movement of the bearing housing in the fxame of the rnachine.
This substantially increases the life of the bearing.
According to one configuration of the invention, the
bearing housing of the idler-roll, which is adapted to yie'd
axially, is connected to the piston-rod of a single-acting hydraulic
piston-cylinder unit. Movement of the beariny housing in the
.
- axial direction of the roll may be very simply compensated for,
by the said single-acting piston-cylinder unit, by setting the
piston-rod and piston at a slight angle to the cylinder. At the
sarne time, the hydraulic piston-cylinder unit may take over and
measure the pressure of the idler roll against the driven roll.
According to another configuration of the invention,
the bearing housing is adapted to move axially in a support. In
the case of the idlex roll, this support is connected to a
double-acting piston-cylinder unit. This is a very advantageous
way of mounting the bearing housing hydrostatically in the support,
thus allowing it to move axially without friction. Furthermore,
the double-acting piston-cylinder unit may be used very advantage-
ously to adjust, and maintain constant, both the width of the gapbetween the pressure rolls and the pressure of the idler roll
against the driven roll.
In accordance with one aspect of the present
invention, there is provided an apParatuS for protectiny bearinqs
in rolling mills, rnore particularly in roller-briquette-
presses, from overloading, the said apparatus comprising a
driven and an idler roll, and at least one of the bearing-
housings thereof being arranged to yield in the axial direction,
characterized in that at least the bearing housing which
~ields in the axial direction is equipped with self-aligning
bearings and cornrnunicates with a hydraulic piston cylinder
unit, the piston thereof being fitted with a seal permitting
deflection of the piston rod at an angle to the longitudinal
axis of the piston.
Further details, characteristics and advantages of the
invention may be gathered from the ex~nples of embodirnent des-
cribed hereinafter in greater detail, in conjunction with the
drawings attached hereto. The invention is therefore illustrated
by way of exarnple in the accornpanying drawings wherein:
Figure 1 is a side elevation of a roller-briquette-press
havlng a single-acting hydraulic piston-cylinder unit arranyed
at the bearing housing of the idler roll, according to the
invention;
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Figure 2 is a plan view of the bearing housing with the
single-acting piston-cylinder unit, partly in section,
Figure 3 is a side elevation of a rolling mill, with a
double-acting plston-cyl.inder unit engaging with the idler-roll
bearing support.
As shown in Figure 1, the roller-briquette-press com-
prises a driven roll 1 and an idler roll 2. Sha~ts 3, 4, arr-anged
at the ends of rolls 1, 2 are mounted, as shown in Figure 2, in
self-aligning roller bearings 5 arranged, in turn, in bearing
housings 6, 7. According to the invention, one of these bearing
housings is displaceable axially in machine-frame 8. Bearing
housing 7, associated with idler roll 2, is connected to piston-
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rod 9 of a single-acting hydraulic piston-cylinder unit 10.
Piston 11 of this unit is fitted with a special seal which very
advantageously allows piston-rod 9, engaging with bearing housing
7 to deflect through a specific angle c~ .
In the event of changes in the length of the roll, as
a result of heating during operation, this very advantageously
allows the bearing housing to move away, thus avoiding additional
axial loads on self-aligning roller bearings 5. The seal on
piston 11, together with the cylinder of piston-cylinder unit 10,
acts as a kind of articulation, allowing piston-rod 9, with
bearing housing 7, to deflect through an angle ~ , without any
leakage occurring in the said hydraulic unit. Self-aligning
roller bearing 5 also acts as an articulation permitting angular
movement of shaft 4 in relation to bearing housing 7. In short,
this is a highly advantageous manner of absorbing the changes
in length, and axial thrust associated therewith, produced,
while the roller-briquette-press is in operation, by heating
of the roll and/or shaft.
Bearing housing 6, which has no piston-cylinder unit,
may also be provided with a mounting adapted to yield in the axial
direction, the said mounting being in the form of an articula-tion
or appropriate resilient material. In this way, the bearings
of the rolling mills, and especially those of roller-briquette-
presses, are reliably protected, according to the invention, from
one-sided loading or overloading, the life of the said bearings
being thus substantially extended~ At the same time, piston-
~ylinder unit 10 may be used, very advantageously, as a means
for pressing idler roll 2 against driven roll 1.
Moreover, as shown in ~'igure 3, bearing housings 12,
13 for rolls 14, 15 may also be adapted, very advantageously, to
move axially in supports 16, 17. Supports 16, arranged at each
end of driven roll 14, are secured to machine frame 1~, whereas
supports 17 for idler roll 15 are adapted to slide in machine-
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frame 18 toward~ driven roll 14. The sliding axial guidance
of bearing houses 12, 13 in supports 16, 17 allow the roller
bearings and bearing housings to move very easily in the axial
direction, whenever axial thrusts occur in opera~ion. In this
case, an almos~ frictionless hydrostatic mounting of bearing
housings 12, 13 in supports 16, 17 is an advantage.
Adjustment of the width of the gap between the rolls,
and of the necessary roll-pressure, is achieved by means of a
double-acting piston-cylinder unit 19, piston-rod 20 of which
engages with support 17. The arrangement illustrated in Figure 3
of bearing housings 12, 13 in supports 16, 17 reliably protects
roll-bearings 14, 15 from over-loading, thus providing a sub-
stantial increase in bearing life in comparison with hitherto-
lcnown arrangements. In addition to this, the use of a double-
acting piston-cylinder unit permits different pressures on eac~
side of the piston to be set and kept constant. In this way,
the inherent radial frequencies of the crusher rolls, arising,
for example, in a smooth-roll cr~sher, may be very advantageously
increased, thus protecting the pressure surface from uneven wear
(corrugations). This also improves, very advantageously, the
damping action of the cylinder of the double-acting piston-
cylinder ùnit.
