The present invention relates to a drive arrangement for roll-pairs
with which the roll shafts are driven synchronously.
Present day roll-pair units included a rolling line of a rolling
mill are comprised of separate parts which are connected to a supportive base structure
and mutually coupled together to form a functional unit with the aid of coupling
devices, which at times have the form of quick-fasteners which enable components
to be separated quickly from one another to facilitate the exchange of mill components
and maintenance. The drawback with this arrangement resides in the number of working
procedures that must be carried out when changing a component, for instance when
changing rolls. Another drawback resides in the amount of work that is required
in installing and trimming such a roll-pair unit so that it can be integrated in
the rolling line. These drawbacks are occasioned, among other things, by the fact
that the roll-pair drive arrangement is often heavy, bulky and is comprised of
many components. Some of these components will be different when the roll-pair
unit is to be driven with the roll-pair shafts in a horizontal position instead
of a vertical position. Furthermore, when switching from one rolled product to
another rolled product, it is often sufficient to replace a roll-pair unit fitted
with horizontal rolls in a rolling line with a similar roll-pair unit that is
fitted with vertical rolls, and vice versa. There is therefore a need to construct
the roll-pair units so that the rolls can be fitted both horizontally and vertically
without needing to change the drive arrangement.
The object of the present invention is to eliminate the aforesaid
drawbacks and to satisfy the aforesaid requirements.
According to the invention, this object is achieved with a drive
arrangement of the kind defined in the introduction wherein it includes an alternating
current motor and a planetary gear mechanism, and the alternating current motor
is placed on one side of the planetary gear mechanism and, in relation to the roll-pair,
on the same side of a plane which passes through the ends of the output shaft
of the alternating current motor and the input shaft of the planetary gear mechanism
as the planetary gear mechanism. This construction provides a lighter and more
compact drive arrangement than drive arrangements that are constructed in accordance
with the known techniques, and enables the drive arrangement to be constructed
as a single manageable unit which can be placed both horizontally and vertically
without needing to be changed.
EP-A1-0 287 674 shows a drive arrangement for roll pairs which includes
an electric motor and a planetary gear mechanism and US-A-4 882 923 shows that
a drive arrangement for a roll-pair with synchronously driven shafts may include
an alternating current motor. However, none of these documents shows or suggests
the placing of the components in the drive arrangement in the manner defined above.
According to one preferred embodiment of the invention, the output
shaft of the alternating current motor and the input shaft of the planetary gear
mechanism are mutually connected by means of a transmission, preferably in the
form of a gear transmission. The drive arrangement also includes a pinion stand
and is constructed to form a single assembly unit which carries the roll unit
containing the roll-pair.
The invention will now be described in more detail with reference
to a preferred embodiment of the invention and also with reference to the accompanying
drawings, in which
- Fig. 1 is a side view of a roll-pair unit provided with a drive arrangement
according to one embodiment of the invention;
- Fig. 2 shows the roll-pair unit in Fig. 1 from above;
- Fig. 3 is a sectional view of the roll-pair unit shown in Fig. 1 with the unit
in a dismantled state;
- Figures 4 and 5 are respective vertical and horizontal sectional views of a
roll-pair unit according to Figure 1 in which the rolls are arranged horizontally;
- Figure 6 is a vertical sectional view of a roll-pair unit according to Figure
1 with the rolls arranged vertically; and
- Figures 7 and 8 are respective sectional views of a convertible supported roll-pair
unit according to Figure 1 with the rolls in a horizontal and a vertical position
The illustrated exemplifying embodiment of a roll-pair unit includes
a roll unit 1, a cassette 2, a pinion stand 3 and a drive unit 4. The roll unit
1 is carried by the cassette 2, which in turn is carried by the pinion stand housing
5, as is also the drive unit 4. Two spindles 6, 7 are journalled in the pinion
stand housing and are in driving connection with the rolls 9, 10 through the medium
of a coupling holder 8 fitted to the housing. The pinion stand housing also carries
a roll hoist mechanism 11. Thus, the drive arrangement comprising the drive unit
4 and the pinion stand 3 has the form of a single assembly unit which also carries
the cassette 2 which supports the roll unit.
The drive unit 4 includes an alternating current motor 12 and a planetary
gear mechanism 13, wherein the motor and the gear mechanism are placed adjacent
one another with the output shaft of the alternating current motor in the same
plane as the input shaft of the planetary gear mechanism. These shafts extend
parallel with one another and are mutually connected by means of a gear transmission
14. The planetary gear mechanism and the alternating current motor are both placed
on that side of the gear transmission which lies proximal to the pinion stand housing.
By using a planetary gear mechanism and by placing this mechanism
and the alternating current motor adjacent one another, there is obtained a roll-pair
unit which occupies only a small amount of space laterally in relation to the
rolling line, while the centre of gravity of the whole of the roll-pair unit will
lie in the central region of the pinion stand housing 5, which is advantageous
from an attachment or fastening point of view. In the case of the illustrated
embodiment, the alternating current motor 12 is placed on one side of the planetary
gear mechanism 13, although the construction which includes a gear transmission
14 which mutually connects the alternating current motor and the planetary gear
mechanism enables the alternating current motor to be placed anywhere around the
periphery of the planetary gearing, for instance above said planetary gearing.
The alternating current motor is attached to the gear transmission housing, and
the gear transmission is, in turn, attached to the planetary gear housing, which
is attached to the pinion stand housing. However, because of its position on one
side of the planetary gear mechanism, the alternating current motor may alternatively
be carried directly by the pinion stand housing, if found desirable.
The alternating current motor may be a conventional motor with a
power output of 300-800 kW and a speed of 1000-3600 r.p.m. Such a motor will weigh
about 2 tonnes and will have a length of about 1.5 m and a diameter of about 0.8
m. The planetary gearing and the gear transmission together have a transmission
ratio of between 85:1 and 8:1, a weight of 3.5 tonnes, a largest diameter of about
1 m and a length of about 1.7 m. The inventive drive arrangement is thus compact
and manageable in comparison with earlier known roll-pair drive arrangements.
Figures 4 and 5 show the roll-pair unit illustrated in Figures 1-3
fitted to a supportive base structure 15 with the rolls in a horizontal position.
In this case, the roll-pair unit is mounted displaceably on the supportive structure
through the medium of outwardly projecting guide flanges 16 each mounted on a respective
side of the pinion stand housing and extending laterally to the longitudinal axis
of the roll-pair unit, said guide flanges 16 coacting with corresponding guides
17 on the Supportive base structure. Mounted on the undersurface of the pinion
stand housing beneath the centre of gravity of the roll-pair unit is an attachment
flange 18 which has attached thereto one end of a rod 19 or the like which forms
part of a displacement mechanism 20 mounted on the supportive base structure.
The displacement mechanism 20 is preferably a rack-and-pinion or screw-nut type
mechanism, although other types of displacement mechanisms are conceivable, such
as hydraulic piston-cylinder type mechanisms. This arrangement enables the rolls
9, 10 to be displaced laterally in relation to the rolling line, by displacing
the whole of the roll-pair unit by means of the displacement mechanism.
The roll-pair unit also includes a component fastening mechanism
21 which is mounted on the pinion stand housing 5 and which functions to fasten
the cassette 2 to said housing, said mechanism being an eccentric type mechanism
for instance, with which rotation of a cylindrical member will bring a surface,
which is eccentric in relation to the rotational centre, into abutment with a
complementary surface on the cassette and therewith press the cassette forcefully
against an abutment surface on the pinion stand housing. Naturally, component
fastening mechanisms other than an eccentric mechanism can be used.
In order to enable rolls to be exchanged, the cassette 2 is connected
to a withdrawal device 22 of known construction when positioned out of engagement
with the pinion stand housing 5, i.e. when the cassette is not gripped by the
eccentric surface on the component fastening mechanism 21. The cassette, and therewith
also the roll unit carried by the cassette, can be moved to the left in the Figures
4 and 5 by means of the withdrawal device 22, until the entire cassette rests
on a carriage 23. The roll unit 1 can be lifted from the cassette with the aid
of an overhead crane or the like and replaced with a new roll unit, or alternatively
the carriage supporting the cassette and roll unit can be moved to one side laterally
in relation to the longitudinal axis of the roll-pair unit and replaced with a
new carriage carrying a replacement cassette.
Figure 6 illustrates a roll-pair unit according to Figures 1-3 mounted
on a supportive base structure 15 with the rolls extending vertically. In this
case, the roll-pair unit is carried by a vertical frame structure 24 firmly mounted
on the supportive base structure 15, this base structure being identical to the
base structure illustrated in Figures 4 and 5. The frame structure 24 carries
the rod or bar 19 which coacts with the attachment flange 18 on the pinion stand
housing 5 and which can be moved by means of the displacement mechanism 20 in the
manner described with reference to Figures 4 and 5. The frame structure 24 is
also provided with guides 17 along which the pinion stand housing can slide. Similar
to the supportive base structure illustrated in Figures 4 and 5, the supportive
base structure 15 of the Figure 6 embodiment includes a cassette withdrawal device
22 and carriages 23 for facilitating roll exchanges.
Figures 7 and 8 illustrate a variant of the invention in which the
roll-pair unit is carried by a frame structure 25 which is pivotally mounted on
a supportive base structure 26 for pivotal movement between a first position in
which the shafts of rolls 9, 10 of one roll-pair unit carried by the frame structure
extend horizontally, and a second position in which the shafts of the rolls 9,
10 extend vertically.
The frame structure 25 is pivotally mounted on the supportive base
structure 26 by means of two shaft-ends which are firmly connected to the frame
structure and project out opposite one another on opposite sides of the frame
structure and each of which extends through a respective bearing box. A lever arm
is fitted to at least one of the shaft-ends projecting out from respective bearing
boxes and a suitable jack or ram means, for instance a hydraulic piston-cylinder
device, is pivotally mounted to the free end of said at least one shaft-end. The
other end of this jack, or ram, is pivotally mounted on the supportive base structure
When swinging the frame structure 25 from the position illustrated
in Figure 7, in which the roll shafts extend horizontally, to the position shown
in Figure 8, in which the roll shafts extend vertically, the roll-pair unit is
conveniently moved to the right in Figure 7, by means of the displacement mechanism
19, 20, at the speed at which the frame structure is swung upwards by means of
the jack or ram means. In this way, when setting-up the roll-pair unit and frame
structure, the centre of gravity will lie close to the pivot axis during the whole
of the pivoting sequence, which is favourable from a loading aspect.
As indicated schematically with the lubricant container 27 in Figures
4-8, the supportive base structures 15 and 26 each incorporate a lubricating system
which functions to lubricate and cool the rotating parts of the roll-pair unit.
The lubricant container 27 has a relatively large volumetric capacity, in the order
of 500 l, so as to enable degasification and cooling of the recycled lubricant,
oil. Although the lubricant containers 27 are shown in the Figures to be carried
by the supportive base structure, it will be understood that these containers,
together with other lubricating system components, such as pumps, couplings and
conduits, can be carried by the pinion stand housing.
Because remaining components of the roll-pair unit are carried by
the pinion stand housing, the roll-pair unit can be assembled by the supplier and
then fitted into the rolling mill line in the form of a unit. This enables the
roll-pair units forming part of a rolling mill line to be fitted, or mounted, very
quickly. Since the pinion stand housing is secured to the supportive base structure
in a very simple manner, the task of fitting the pinion stand housing to the base
structure can be quickly achieved without the assistance of qualified personnel.
Furthermore, the roll-pair units can be used with the rolls extending horizontally
or vertically without change, which naturally reduces the need of replacement
roll-pairs, since only one type of unit need be kept in storage. Even when not
using a roll-pair unit which is supported convertably on a supportive base structure,
the construction of a new rolling mill line for a new product can be simplified
in many cases by using the same roll-pair unit as that used in the old rolling
mill line with the roll shafts extending in another direction. Since the roll-pair
unit can be lifted in its entirety in accordance with the present invention, a
change in the direction in which the roll shafts extend can be easily achieved.
Furthermore, the invention results in a decrease in the number of components in
the roll-pair unit drive arrangement in comparison with known roll-pair units,
meaning that the number of movable parts which must be enclosed and maintained
is fewer than in the case of the earlier known technique.
Because the inventive drive arrangement is very short, due to the
positioning of the alternating current motor and the use of planetary gearing,
a rolling line comprised of roll-pair units which include such drive arrangements
will occupy only a small space in comparison with a rolling line that is comprised
of roll-pair units which include conventional drive arrangements, therewith enabling
a reduction in the height and breadth dimensions of the rolling mill.
It will be understood that the described drive arrangement can be
modified in different ways within the scope of the present invention as defined
by the appended claims. For instance, in addition to transmitting the motor drive
torque to the planetary gearing, the gear transmission can also be given a down-stepping
function or even an up-stepping function, so as to form a roll-pair unit reduction
gear together with the planetary gearing. It is also possible to achieve a given
degree of standardization, by using similar planetary gearing at different locations
in the rolling mill line, owing to the fact that the necessary differences in
transmission ratios can be achieved with the aid of different gears. The invention
is therefore limited solely by the content of the following Claims.