Note: Descriptions are shown in the official language in which they were submitted.
ROLLING UNIT 21~1 7 5 9
ACKG~OUND OF THE lN Vl~;N'l lON
This invention relates to a rolling unit having at least two
successive roll stands for rolling products such as steel bars or
wire rods, in which the axis-to-axis distance between the rolls in
S one roll stand and those of the other roll stand is shortened so as
to eliminate the need for interstand guides.
Rolling mills are known in which a plurality of roll stands
are serially arranged along a pass line, and the product is rolled
to a predetermined size by passing it through these roll stands.
1~ Each roll stand is equipped with a pair of rolls disposed rotatably
in a housing, and the product is passed through a roll pass defined
by grooves in the rolls. In the roughing and intermediate sections
of the mill, the pass sequence can be ~oval-round" in which oval
and round roll passes are alternately disposed sequentially.
Alternatively, the pass sequences can be "rhombic-square" in which
rhombic and square roll passes are alternately disposed
sequentially. In the finishing section of the mill, however, an
oval-round pass sequence is usually employed to deliver a round
product from the mill.
In the oval-round pass sequence, a roller guide is disposed at
the inlet side of each round pass, so that the product can be fed
in a proper orientation into the round pass and thus can be
accurately rolled. In the rhombic-square pass sequence, a similar
guide is also disposed at the inlet side of each square pass so as
to optimize area reductions.
In the rolling mill described above, a roll parting ad~ustment
device must inevitably be employed for adjusting the clearance or
21417~3
-parting" between the roll pairs so as to adjust the cross-
sectional ~;me~ions of the product passing therebetween. The roll
parting adjustment device is designed to move one roll closer to or
farther from the other roll, the latter roll being fixed at a
predetermined position.
When the parting between the rolls is adjusted, the position
of the associated roller guide disposed in the rolling unit must be
adjusted correspondingly, causing an attendant loss of valuable
production time. Further, since misguiding of the product by the
roller guide leads to defects, maintenance of guide bearings,
checking of surface flaws on the guide rollers, checking of the
rolling state of the rollers, etc. must frequently be carried out.
It can also be pointed out that the roller guides disposed between
the respective roll stands make the structure of the rolling
equipment more complicated and costly.
In such rolling mills, since housing posts for supporting the
roll parting adjustment mechanisms are located on the inlet side
and outlet side, the distance between the upstream roll stand and
the downstream roll stand increases by the thickness of the posts.
Additionally, the roller guides disposed between the roll stands
also take up space, with the result that the overall length of the
installation is disadvantageously increased.
A general objective of the present invention is to avoid or at
least substantially mitigate the problems noted above by achieving
a significant reduction in the distance between roll stands in a
rolling mill.
A companion objective of the present invention is to elimin~te the need for interstand
guides, thereby substantially simplifying the task of adjusting the mill to accommodate
different product sizes.
SUMMARY OF THE INVENTION
In accordance with the present invention there is provided a rolling unit comprismg
at least two roll stands arranged along a rolling line, each roll stand having a pair of work
rolls carried on roll shafts, the roll shafts being journalled for rotation in eccentric sleeves
which in turn are journalled for rotation in a housing, the eccentric sleeves being spaced from
opposite first and second sides of the housing by first and second housing portions, the width
of the first housing portion measured in the direction of the rolling line being less than the
width of the second housing portion measured in the same direction, means in the second
housing portion for rotatably adjusting the eccentric sleeves simultaneously in order to vary
the spacing between the work rolls, the housings of the roll stands being arranged such that
the axes of the work rolls of one roll stand are offset by 90~ with the respect to the axes of
the work rolls of the other roll stand, with the first sides of the housings being arranged in
a confronting relationship.
In the present invention, twisting of the product during the rolling process caneffectively be prevented without having to resort to the use of interstand guides. As a
consequence, the overall design of the rolling unit is simplified, with attendant reductions in
capital investment. Furthermore, occurrence of defective products attributable to improper
guide settings can be elimin~ted, and the intricate guide checking and maintenance operations
also can be avoided. Since the rolling unit can be downsized, the entire length of the
installation is redllce~l, enabling efficient utilization of plant space.
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214175~
IEF DESC~IPTION OF THE DRAWINGS
The features of this invention that are believed to be novel
are set forth with particularity in the appended claims. The
invention, together with the objects and advantages thereof, may
best be understood by reference to the following description of the
preferred embodiments taken in conjunction with the accompanying
drawings in which:
Fig. 1 shows in horizontal cross-sectional view the major
portion of a rolling unit according to a preferred embodiment of
the invention;
Fig. 2 shows a partially cut-away front view of the rolling
unit according to the preferred embodiment of the invention;
Fig. 3 shows a plan view of the rolling unit according to the
preferred embodiment of the invention;
Fig. 4 shows a vertical cross-sectional view of a first roll
stand in the rolling unit;
Fig. 5 shows schematically a plan view of the first roll stand
in the rolling unit;
Fig. 6 shows schematically an explanatory view of a roll
parting adjustment mechanism in the first roll stand;
Fig. 7 shows in explanatory view the arrangement of rolls in
each roll stand of the rolling unit according to the preferred
embodiment of the invehtion;
Fig. 8 shows an explanatory view illustrating the relationship
between a pair of opposing rolls which are rolling a small-diameter
product;
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~ Fig. 9 shows an explanatory view illustrating the relationship
between the axes of the rolls assuming the state shown in Fig. 8
and the axis of an eccentric member;
Fig. 10 shows an explanatory view illustrating the
relationship between a pair of opposing rolls which are rolling a
large-diameter product;
Fig. 11 shows an explanatory view illustrating the
relationship between the axes of the rolls assuming the state shown
in Fig.10 and the axis of the eccentric member; and
Fig. 12 shows an explanatory view of a mill installation in
which several rolling mills are disposed.
DETAILED DESCRIPTION OF THE INVENTION
The rolling unit according to this invention will be described
by way of a preferred embodiment referring to the attached
drawings. It should be noted here that, in the preferred
embo~iment described below, rolling units 10 are employed as the
sizing mills for finish rolling in the rolling mill shown in Fig.
12. However, the rolling units 10 can suitably be employed in the
intermediate line. Each rolling unit 10 has three roll stands 12,
14, 16 arranged serially, with rolls 13, 15, 17 being arranged in
such a way that the rotational axes of any downstream roll pair (15
or 17) is offset from ~hose of the adjacent upstream roll pair (13
or 15) by an angle of 90~, as shown in Figs. 2 and 3. In this
embo~iment, the axes of the rolls 13 disposed in the first roll
stand 12 located in the upstream position with respect to the
direction of rolling a product 20 and those of the rolls 17 in the
21417~9
~ird roll stand 16 located in the downstream position are set
horizontally, and the axes of the rolls 15 disposed in the second
roll stand 14 located between the first and second roll stands 12
and 16 are set perpendicularly, as shown in Fig. 7. The rolls 13,
15, 17 in these three roll stands 12, 14, 16 constituting the
rolling unit 10 are designed to be driven by one drive motor 18 via
a speed reducer 19.
The axis-to-axis distance P between the rolls 13 of the first
roll stand 12 and rolls 15 of the second roll stand 14 is set to be
not more than 1.2 times the diameter R of the roll 13 (15, 17).
The product 20 can be guided accurately and fed to the roll pass of
the roll stand 14 by thus shortening the axis-to-axis distance P
between the adjacent rolls 13 and the rolls 15, without employing
any guide means for guiding the product 20 between these two roll
stands 12, 14. If a mechanism to be described later is employed
for adjusting the parting between the opposing roll pairs 13, 15 or
17 in the roll stands 12, 14 or 16, the axis-to-axis distance P
between the rolls 13 and the rolls 15 still can be kept within the
above noted range of not more than 1.2 times the roll diameter R.
Fig. 1 shows in horizontal cross-sectional view a first roll
stand 12 and a second roll stand 14 in the rolling unit 10. Since
the structure of the first roll stand 12, that of the second roll
stand 14 and that of the third roll stand 16 are substantially the
same except that they are arranged side by side in such a way that
the rotational axes of the rolls 15 may be offset by 90~ from those
of the other rolls 13, 17, only the structure of the first roll
stand 12 will be described, and a detailed description of the
second and third roll ~tand3 14 16 will be omitted. The
co--.Lol,ents of the ~econd roll ~tand 14 and the third roll stand 16
co.Lespo~di~g to the component~ of the first roll ~tand 12 are
identified by the same reference number~, ~e3~ec~ively.
S A pair of op~ings 24a are defined in each housing 24. The
housings are di-Qposed on a bed plate 22 of the rolling unit 10 as
Qhown in Fig. 2. The op~ning3 24a are positione~ closer to the
downQtream end of the hou3ing 24 above and below the pas3 line PL
along which the ~.oduc~ 20 i~ fed. The openi~gs 24a are
~eLL~ cular to the pa~s line P~, as shown in Fig. 4. AQ shown in
Fig. 1, a pair of nc~c..~ric members 26 are rotatably Qu~oL~ed in
the op~ing~ 24a .e~pactiYely and an Qcc---Lric or~ning 26a is
defined in each cccenLric member 26 3uch that the axis of the
eccentric opening 26a is offset from that of the coLLe3~0n~ing
op-ning 24a. A pair of roll Jhafts 28 extend through and are
rotatably suyyo.~ed in these ceecn~ric openingS 26a via bearings
30. The pair of roll~ 13 are fitted on these roll ~haft~ 28 for
rotation therewith. AJ clearly Qhown in Fig. 9 each roll ~haft 28
is set ~uch that the axis C~ thereof i9 laterally offset from the
axis C2 of the Co~ L)vl)Ai~g eccrn~ric member 26, when the roll
shaft 28 i~ in~erted through the eccentric opening 26a of the
eccentric member 26 and that the axi~ Cl of the roll ~haft 28 may
be shifted by rotating the e~cenLric member 26 in clockwise or
counterclockwi~e direction by a mechani~m to be described later.
A pair of adju~ting shafts 32 inter~ecting with the roll
shafts 28 are rotatably ~U~G- Led in up~tream portions of the
housing 24 so as to intersect the eccentric member~ 26. Worm~ 34
.~
2141759
. .
o~e fitted on each adjusting shaft 32 to be rotatable integrally
therewith at the positions intersecting the respective eccentric
members 26. Each worm 34 is designed to engage with a toothed
portion 26b formed on the circumference of the corresponding
eccentric member 26. The two worms 34 disposed on each adjusting
shaft 32 are of opposite hand; whereas the two worms 34 engaging
the eccentric members 26 which are fitted on the same roll shaft 28
are of the same hand. A gear 36 is fitted on one end portion of
each adjusting shaft 32 to be rotatable integrally therewith. The
gears 36 fitted to the respective adjusting shafts 32 are rotated
in the same direction by rotating the adjusting gear 38 in the
clockwise or counterclockwise direction by a suitable drive means
such as a motor, whereby the corresponding eccentric members 26 are
rotated via the respective worms -34. Thus, the axis-to-axis
distance between the roll shafts 28 supported by the pair of
eccentric members 26 is varied (see Figs. 9, 11) to adjust the
parting between the opposing rolls 13 (see Figs. 8, 10).
As described above, in the first roll stand 12 employing a
roll parting adjustment mech~n;sm utilizing eccentric members 26,
the downstream wall of the housing 24 (the side toward which the
roll shafts 28 are biased) is designed to be extremely thin, as
shown in Fig. 4. Similarly, in the second roll stand 14, the roll
shafts 28 are disposed in the housing 24 so as to be biased
upstream, as shown in Fig. 1, whereby the upstream wall of the
housing 24 is designed to be extremely thin. The first roll stand
12 and the second roll stand 14 are arranged adjacent to each other
such that the thin wall sides of their respective housings 24 face
21~175g
~ch other, whereby the axis-to-axis distance P between the rolls
13 of the first roll stand 12 and the rolls 15 of the second roll
stand 14 can be reduced to not more than 1.2 times the diameter R
of the rolls 13 (15). The second roll stand 14 and the third roll
S stand 16 are arranged in such a way that the side of the housing 24
in the second roll stand 14 where the roll parting adjustment
mechanism is disposed may oppose to the third roll stand 16, so
that the axis-to-axis distance between the rolls 15 and the rolls
17 is greater than 1.2 times the diameter R of the roll 13 but not
more than 2R.
In operation, a product 20 having underwent a rolling process
in the upstream line of the installation shown in Fig. 12 is fed to
the first roll stand 12 of the rolling unit lO, shown in Fig. 2 and
passed through the roll pass defined between the opposing rolls 13
of the first roll stand 12 to undergo a predetermined reduction.
The thus reduced product 20 is then fed through the roll pass
defined by the rolls 15 of the second roll stand 14. Since the
first roll stand 12 and the second roll stand 14 are arranged such
that the axis-to-axis distance P between the rolls 13 and the rolls
15 is not more than 1.2 times the diameter of the roll 13, the
product 20 can accurately be directed to the roll pass of the
second roll stand 14 without providing any interstand guiding means
as conventionally employed. The roll 13 in the first roll stand 12
also serve as the guiding means for guiding the product 20 to the
second roll stand 14, so that twisting of the product 20 can
effectively be prevented. Incidentally, since a very light
reduction commonly referred to as a "skin pass" is designed to be
-- 10 --
~ ~ k ~
.....
effected in the final roll pass in the finish rolling, twisting of
the product 20 can be held within a tolerable range, even if the
axis-to-axis distance between the rolls 15 in the second roll pass
14 and the rolls 17 in the third roll pass 16 i8 greater than 1.2
times but not greater than 2 times the roll diameter.
When a small-diameter product 20 i~ to be rolled, the
clearance between the opposing rolls 13 in the first roll pass 12
is set to a predeter~i n~ parting, as shown in Fig. 8, and the
rolls 13 are rotated in the directions opposite to each other,
where the axes C~ of the roll shafts 28 and the axes C2 of the
eccentric ~mhers 26 are in the relationship as shown in Fig. 9.
Accordingly, if the product 20 is fed between the rolls 13 of the
first roll ~tand 12, the product 20 unde yoes a predetermine~
reduction and is then fed to the second roll stand 14.
When a larger diameter product 20 is to be rolled in the
rolling unit 10 in accordance with an order change, the adjusting
gear 38 is rotated in the predetermined direction by a drive means
to rotate the adjusting shafts 32 in the same direction. Since the
worm~ 34 disposed on each adjusting shaft 32 are engaged with the
toothed portions 26b of the correspon~ing eccen~ric members 26
fitted on the upper or lower roll shafts 28, the eccentric members
26 can be rotated in the predet~rmine~ direction in the openings
24a defined through the housing 24 as the correspo~ing adjusting
shaft 32 rotates. The upper eccen~ric member 26 and the lower
eccentric mem~er 26 rotate in opposite directions to change the
distance between the axes Cl of the roll shafts 28 ~u~o.Led by the
eccentric m~c.~ 26, as shown in Fig. 11. Thus, the parting
,, ~,
2141759
_~etween the opposing rolls 13 fitted on the roll shafts 28,
respectively, is increased, as shown in Fig. 10. When the parting
between the rolls 13 reaches the preset level depending on the size
of the product 20, the rotation of the adjust gear 38 is stopped to
complete the parting adjustment.
It will be understood that a number of variations of the
arrangement of the rolls of the respective roll stands in the
rolling unit can be assumed other than the illustrated embodiment.
For example, the axes of the rolls 13 of the first roll stand 12
and those of the rolls 17 in the third roll stand 16 may be
perpendicular, and the axes of the rolls 15 in the second roll
stand 14 may be horizontal. Further, in the preferred embodiment
described above, the rolling unit consists of three roll stands.
However, the rolling unit may of course consist of only two roll
stands. Further, -the roll stands in the rolling unit may
respectively be driven by independent drive motors.
It will be apparent to those skilled in the art that the
present invention may be embodied in may other specific forms
without departing from the spirit or scope of the invention.
Therefore, the present embodiment is to be considered as
illustrative and not restrictive and the invention is not to be
limited to the details given herein, but may be modified within the
scope of the appended claims.
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