EP4019156B1

EP4019156B1 - Rolling mill, method for manufacturing rolling mill, and method for modifying rolling mill

Info

Publication number: EP4019156B1
Application number: EP20930355.1A
Authority: EP
Inventors: Kenji Horii; Akio Kuroda; Tatsunori Sugimoto; Akira Sako
Original assignee: Primetals Technologies Japan Ltd
Current assignee: Primetals Technologies Japan Ltd
Priority date: 2020-04-07
Filing date: 2020-04-07
Publication date: 2023-12-13
Anticipated expiration: 2040-04-07
Also published as: EP4019156A4; EP4019156A1; CN114340811A; WO2021205548A1

Description

Technical Field

The present invention relates to a rolling mill, a manufacturing method for a rolling mill, and a modification method for a rolling mill.

Background Art

Regarding roll stands, especially duo or quarto roll stands, including bending and balancing devices for axially displaceable rolls, Patent Document 1 states that a fixed guide block is fixed on both sides in a window of each roll stand at the same level as roll inserts, the force of bending cylinders is transmitted to the roll inserts which are guided axially in a vertically displaceable manner, the lengths of the bending cylinders on upper and lower piston ends are larger than the respective widths thereof, and the longitudinal axes of the bending cylinders extend in the direction of axial displacement of the rolls. The rolling mill of Patent Document 1 has the features in the pre-characterizing portion of Claim 1 in common with the invention.
In addition, as an example bending device for two work rolls of a roll stand, Patent Document 2 states that the bending device has guide blocks disposed in lateral roll uprights for each of two vertically adjustable pressure transmission elements on which the work rolls are supported via inserts, two bending cylinders each of which is disposed between the pressure transmission elements and has a piston rod which acts on a pressure transmission element, and a cylinder formed by the respective other pressure transmission element, and that, in order to provide advantageous design conditions, the L-shaped pressure transmission elements have a longer, vertical limb and a shorter, horizontal limb, the limbs of the pressure transmission elements are disposed opposite each other in pairs in a plane parallel to the work rolls, and the longer limbs of the pressure transmission elements are mounted in vertical guides in the respective guide block and accommodate a cylinder of the bending cylinders, whose piston rods act on the shorter limbs of the respective other pressure transmission element.

Prior Art Document

Patent Documents

Patent Document 1: European Patent No. 1294499
Patent Document 2: U.S. Patent No. 6164111

Summary of the Invention

Problems to be Solved by the Invention

There is known a rolling mill that has a shift function of causing rolling rolls to be displaced in roll axis directions and a bending function of causing pressurizing forces to act on bearings of the rolls in directions perpendicular to the axes, to thereby control the shape of a rolled material by using associated action of displacement of the rolls and bending forces of the rolls.
In such a rolling mill, the positions of bearings and bending cylinders change depending on the positions of shifted rolls. Thereby, the lifetime of the bearings may become shorter if offset loads act on the bearings. Particularly, this becomes noticeable at rolls having large shift amounts.
There are known technologies for suppressing such offset loads that act on bearings and extending the lifetime of the bearings, and, for example, there are technologies described in Patent Documents 1 and 2.
For example, in a structure described in Patent Document 1, an upper case and a lower piston case are disposed and are pressed by a piston, thereby making it possible to cause bending forces to act on a bearing housing. Careful consideration is given to a pendulum support disposed between the piston, the upper case, and the lower piston case such that the moment is prevented from acting on the piston.
In addition, Patent Document 2 discloses a structure in which vertical limbs and horizontal limbs having bending cylinders disposed therein slide in vertical guides to thereby cause bending forces to act on inserts. Thereby, a moment generated to the bending device due to the shifting of rolls can be received, and bending forces are caused to act on substantially the center of a bearing.
In both of Patent Documents 1 and 2, bending forces are caused to act on substantially the center of a bearing in a bearing housing when rolls have shifted. Here, these devices are referred to as "bearing-center-pressing bending-force applying devices" for convenience in the present specification.
During rolling, a horizontal backlash (gap) is generated in a roll bearing housing in some cases. In order to eliminate this backlash, it is effective to dispose backlash elimination cylinders that apply forces in a rolling direction to bearings.
Because the bearing-center-pressing bending-force applying devices mentioned above have large sizes, there is a problem that it is difficult to secure spaces for disposing backlash elimination cylinders in the structures of the bending devices of the conventional technologies mentioned above, and disposing backlash elimination cylinders leads to a size increase of the structure around bearings.
For example, in the technology described in Patent Document 1, because the upper case and the lower piston case require large spaces, there is not a space for additionally disposing backlash elimination cylinders in a guide block.
In addition, in the technology described in Patent Document 2, because the members of the vertical limbs and the horizontal limbs require large spaces, it is difficult to secure spaces for installing backlash elimination cylinders in a guide block.
Furthermore, even in a case where backlash elimination cylinders 1760 are successfully disposed on both sides of each bearing-center-pressing bending-force applying device 1740 as illustrated in FIG. 1, pressing portions of the backlash elimination cylinders 1760 are deviated from liner portions of bearings 1790 as indicated in a region X or a region Y of FIG. 1.
While it is necessary to make the liners longer in order to introduce backlash elimination cylinders even in such a case, this leads to a problem that the sizes of portions around bearing housings 1712 increase.
The present invention provides a rolling mill in which backlash elimination cylinders can be disposed without size increases of devices as compared to conventional devices, and a manufacturing method and a modification method for such a rolling mill.

Means for Solving the Problems

The present invention includes a plurality means for solving the problems described above. It is defined in the independent claims. Further advantageous features are set out in the dependent claims.

Advantages of the Invention

According to the present invention, it is possible to dispose backlash elimination cylinders without size increases of devices as compared to conventional devices. Problems, configurations, and advantages other than those described above will become apparent from the following explanation of embodiments.

Brief Description of the Drawings

FIG. 1 is a plan view for explaining details of a work roll portion in a case where backlash elimination cylinders are applied to a rolling mill in a known example.
FIG. 2 is a figure illustrating an overview of a rolling facility including rolling mills according to a first embodiment of the present invention.
FIG. 3 is a front view for explaining an overview of a rolling mill according to the first embodiment.
FIG. 4 is a cross-sectional view taken along A-A' in FIG. 3.
FIG. 5 is a cross-sectional view taken along B-B' in FIG. 3.
FIG. 6 is a cross-sectional view taken along C-C' in FIG. 3.
FIG. 7 is a plan view for explaining details of a work roll portion in the rolling mill according to the first embodiment.
FIG. 8 is a plan view for explaining details of a work roll portion in a rolling mill according to a second embodiment of the present invention.
FIG. 9 is a front view for explaining an overview of a rolling mill according to a third embodiment of the present invention.
FIG. 10 is a cross-sectional view taken along D-D' in FIG. 9.
FIG. 11 is a plan view for explaining details of a work roll portion in the rolling mill according to the third embodiment.

Modes for Carrying Out the Invention

Embodiments of a rolling mill, a manufacturing method for a rolling mill, and a modification method for a rolling mill according to the present invention are explained below with reference to the figures. Note that identical or corresponding constituent elements in the figures used in the present specification are denoted by identical or similar reference characters, and repetitive explanations regarding these constituent elements are omitted in some cases.

A first embodiment of the rolling mill, the manufacturing method for a rolling mill, and the modification method for a rolling mill according to the present invention is explained with reference to FIG. 2 to FIG. 7. FIG. 2 is a figure illustrating an overview of a rolling facility including rolling mills according to the first embodiment of the present invention, FIG. 3 is a front view for explaining an overview of a rolling mill, FIG. 4 is a cross-sectional view taken along A-A' in FIG. 3, FIG. 5 is a cross-sectional view taken along B-B' in FIG. 3, FIG. 6 is a cross-sectional view taken along C-C' in FIG. 3, and FIG. 7 is a plan view for explaining details of a work roll portion.
First, the overview of the rolling facility including rolling mills according to the present embodiment is explained with reference to FIG. 2.
As illustrated in FIG. 2, a rolling facility 1 includes a plurality of rolling mills that perform hot rolling of a rolled material 5 into a strip. The rolling facility 1 has a controller 80 and seven stands which are a first stand 10, a second stand 20, a third stand 30, a fourth stand 40, a fifth stand 50, a sixth stand 60 and a seventh stand 70 from a rolled material 5 entry side. In the rolling facility 1, each of the first stand 10, the second stand 20, the third stand 30, the fourth stand 40, the fifth stand 50, the sixth stand 60, and the seventh stand 70 and a portion of the controller 80 that controls the corresponding stand correspond to what is called a rolling mill in the present invention.
Note that the rolling facility 1 is not limited to a rolling facility including seven stands like the one illustrated in FIG. 2 and can be a rolling facility including at least two stands.
Next, part of the overview of a rolling mill according to the present invention is explained with reference to FIG. 3. Note that, while the seventh stand 70 illustrated in FIG. 2 is explained as an example in FIG. 3, the rolling mill according to the present invention can be applied to any one of the first stand 10, the second stand 20, the third stand 30, the fourth stand 40, the fifth stand 50, and the sixth stand 60 illustrated in FIG. 2.
In FIG. 3, the seventh stand 70, which is a rolling mill according to the present embodiment, is a rolling mill including four rolls that rolls the rolled material 5, and has housings 700, the controller 80, and a hydraulic device (illustration omitted).
The housings 700 include an upper work roll 710 and a lower work roll 711, and an upper backup roll 730 and a lower backup roll 731 that support the upper work roll 710 and the lower work roll 711 by making contact with the upper work roll 710 and the lower work roll 711, respectively.
With respect to the rolls, on each of a drive side and a work side, a bearing 790 (see FIG. 7) that is shiftable in a roll axis direction along with the upper work roll 710 and receives a load from the roll is disposed at an axial end portion of the upper work roll 710, and the bearings 790 are supported by upper-work-roll bearing housings 712.
Similarly, on each of the drive and work sides, a bearing (omitted for the convenience of illustration) is disposed at an axial end portion of the lower work roll 711, and the bearings are supported by lower-work-roll bearing housings 713.
In the present embodiment, the upper work roll 710 is configured to be shiftable in the roll axis direction with use of a shift cylinder 715 like the one illustrated in FIG. 4 via the work-side upper-work-roll bearing housing 712. Similarly, the lower work roll 711 is also configured to be shiftable in the roll axis direction with use of a shift cylinder 716 like the one illustrated in FIG. 4 via the work-side lower-work-roll bearing housing 713.
Referring back to FIG. 3, an entry-side fixation member 702 is fixed to the rolled material 5 entry-side housing 700. An exit-side fixation member 703 is fixed to the rolled material 5 exit-side housing 700 such that the exit-side fixation member 703 faces the entry-side fixation member 702.
In the seventh stand 70, as illustrated in FIG. 3, FIG. 5, and FIG. 6, on each of the work and drive sides, upper-work-roll bending cylinders 740 disposed in the entry-side fixation member 702 and a work-roll bending cylinder 741 disposed in the exit-side fixation member 703 support the upper-work-roll bearing housing 712, and, by driving these cylinders as appropriate, it becomes possible to apply bending forces vertically to the bearings of the upper work roll 710 and cause the upper work roll 710 to perform bending.
Similarly, on each of the work and drive sides, lower-work-roll bending cylinders 744 disposed in the entry-side fixation member 702 and the work-roll bending cylinder 741 disposed in the exit-side fixation member 703 mentioned above support the lower-work-roll bearing housing 713, and, by driving these cylinders as appropriate, it becomes possible to apply bending forces vertically to the bearings of the lower work roll 711 and cause the lower work roll 711 to perform bending.
Among these cylinders, the upper-work-roll bending cylinders 740 and the work-roll bending cylinder 741 are disposed such that bending forces are applied to the bearings of the upper work roll 710 that makes contact with the rolled material 5 toward a vertical increase side (away from the rolled material) to cause the upper work roll 710 to perform bending (first cylinders).
Similarly, the lower-work-roll bending cylinders 744 and the work-roll bending cylinder 741 are disposed such that bending forces are applied to the bearings of the lower work roll 711 that makes contact with the rolled material 5 toward the vertical increase side to cause the lower work roll 711 to perform bending (first cylinders).
As illustrated in FIG. 3 and FIG. 5, for the purpose of eliminating backlashes, in the entry-side fixation member 702 on the rolled material 5 entry side, an upper-work-roll bearing-housing backlash elimination cylinder 760 is disposed such that a horizontal force, specifically, a pressing force in the rolling direction, is applied to the upper work roll 710 via a liner (illustration omitted) of the upper-work-roll bearing housing 712 (second cylinder).
Similarly, in the entry-side fixation member 702, a lower-work-roll bearing-housing backlash elimination cylinder 762 is disposed such that a pressing force is applied to the lower work roll 711 in the rolling direction via a liner of the lower-work-roll bearing housing 713 (second cylinder).
Due to these cylinders, desired forces can be applied to the work roll 710 and the like in directions orthogonal to the roll axis direction.
Referring back to FIG. 3, on each of the drive and work sides, a bearing (illustration omitted) is disposed at an axial end portion of the upper backup roll 730, and these bearings are supported by upper-backup roll bearing housings 732. Similarly, on each of the drive and work sides, a bearing (illustration omitted) is disposed at an axial end portion of the lower backup roll 731, and these bearings are supported by lower-backup roll bearing housings 733.
In addition, as illustrated in FIG. 3, in the exit-side housing 700, upper-backup roll bearing-housing backlash elimination cylinders 780 are disposed such that horizontal forces are applied to the upper backup roll 730 via the upper-backup roll bearing housings 732. Similarly, in the exit-side housing 700, lower-backup roll bearing-housing backlash elimination cylinders 782 are disposed such that horizontal forces are applied to the lower backup roll 731 via the lower-backup roll bearing housings 733.
The hydraulic device is connected to hydraulic cylinders such as the bending cylinders, the backlash elimination cylinders, or the shift cylinders that are mentioned above or rolling cylinders (illustration omitted) that apply roll forces for rolling the rolled material 5 to the upper work roll 710 and the lower work roll 711. The hydraulic device is connected to the controller 80.
The controller 80 performs actuation control of the hydraulic device to supply and discharge a hydraulic fluid to and from the bending cylinders and the like mentioned above, to thereby perform drive control of the respective cylinders.
Next, with respect to the rolls, configurations related to the upper work roll 710 are explained with reference to FIG. 6. Note that the lower work roll 711 also can have configurations equivalent to those of the upper work roll 710. Their configurational details are substantially the same as those of the upper work roll 710, and thus, explanations thereof are omitted.
As illustrated in FIG. 5, in the present embodiment, on each of the drive and work sides of the upper work roll 710, two upper-work-roll bending cylinders 740 are disposed in the roll axis direction on the rolled material 5 entry side. In addition, the upper-work-roll bearing-housing backlash elimination cylinder 760 is disposed between the two upper-work-roll bending cylinders 740. That is, on the entry side in the rolling direction, the upper-work-roll bending cylinder 740, the upper-work-roll bearing-housing backlash elimination cylinder 760, and the upper-work-roll bending cylinder 740 are disposed axially in this order.
Meanwhile, as illustrated in FIG. 6, in the present embodiment, on each of the drive and work sides of the upper work roll 710, the work-roll bending cylinder 741 is disposed on the rolled material 5 exit side.
The work-roll bending cylinder 741 is disposed to be positioned between the two upper-work-roll bending cylinders 740 disposed on the entry side when seen in the rolling direction and, more suitably, is disposed such that the axial position of the work-roll bending cylinder 741 coincides with the axial position of the upper-work-roll bearing-housing backlash elimination cylinder 760 on the rolled material 5 entry side.
Further, in the present embodiment, members 712A and 713A that are disposed between the work-roll bending cylinder 741 and the respective bearing housings 712 and 713 and receive bending forces from the work-roll bending cylinder 741 are disposed on the rolled material 5 exit side.
It is desirable that the members 712A and 713A are configured to be at least partially, more suitably entirely, axially shiftable along with the respective bearing housings 712 and 713. Further, it is desirable that the members 712A and 713A are configured such that the axial positions thereof are shiftable between the two bending cylinders 740 when seen from the entry or exit side in the rolling direction.
It is desirable that the members 712A and 713A each have therein a portion whose horizontal cross-sectional area is larger on the side of the bearing housing 712 or 713 than on the side of the bending cylinder 741, and as illustrated in FIG. 6, it is desirable that the members 712A and 713A each have a protruding shape whose cross-sectional area is smaller on the side of the work-roll bending cylinder 741.
In addition, it is desirable that the members 712A and 713A each have therein a portion whose axial length is longer on the side of the bearing housing 712 or 713 than on the side of the bending cylinder 741.
Note that, while the shapes of the members 712A and 713A in the rolling direction are not limited particularly, it is desirable that the members 712A and 713A each have a protruding shape, as illustrated in FIG. 6, whose cross-sectional area is smaller on the side of the work-roll bending cylinder 741, taking into consideration their roles of effectively transmitting bending forces from the work-roll bending cylinder 741 to the bearing housings 712 and 713.
Note that, while FIG. 6 illustrates the case where the members 712A and 713A are formed separately from the respective bearing housings 712 and 713, it is also possible to provide configurations equivalent to the members 712A and 713A integrally at portions of the bearing housings 712 and 713 where the bearing housings 712 and 713 make contact with the work-roll bending cylinder 741. This similarly applies also to each embodiment to be described later.
In addition, the shapes of the members 712A and 713A are also not limited to the forms illustrated in FIG. 6, and the members 712A and 713A can adopt various other shapes such as a simple rectangular parallelepiped shape. This similarly applies also to other embodiments.
Next, details of the drive control of the upper-work-roll bending cylinders 740, the work-roll bending cylinders 741, and the upper-work-roll bearing-housing backlash elimination cylinders 760 in the present embodiment are explained with reference to FIG. 7, Table 1, and the like. The drive control of them is executed by the controller 80 that performs drive control of the hydraulic device.
In the present embodiment, an axial center position of the bearing 790 that supports the work roll 710 is disposed between two upper-work-roll bending cylinder 740,e1 and upper-work-roll bending cylinder 740,e2 disposed on the entry side, and when bending of the work roll 710 is performed, the two upper-work-roll bending cylinder 740,e1 and upper-work-roll bending cylinder 740,e2 disposed on the entry side are driven, and also the work-roll bending cylinder 741 disposed on the exit side is driven.
At this time, it is desirable that a difference between a total output force of the two upper-work-roll bending cylinder 740,e1 and upper-work-roll bending cylinder 740,e2 disposed on the entry side and an output force of the work-roll bending cylinder 741 disposed on the exit side is kept within a predetermined range. Preferably, the resultant force of the roll bending cylinders is caused to act on a roll axis line.
In addition, it is desirable that output forces of the upper-work-roll bending cylinder 740,e1 and the upper-work-roll bending cylinder 740,e2 are the same, and that the resultant force of the bending cylinder 740,e1 and the bending cylinder 740,e2 and the output force of the work-roll bending cylinder 741, which corresponds to a bearing-center-pressing bending-force applying device, on the exit side act as the total of entry-side and exit-side bending forces on the bearing housing 712 in the vicinity of the roll axis line in a pass direction.
Here, assume that the shift amount of the upper work roll 710 at the time when the center of the bearing 790 in the bearing housing 712 shifts within a section Ls, that is, the shift amount of the axial center of the bearing 790, is L1 (the shift amount on a drive direction side is regarded as a positive amount), and L1 = Ls/2 is satisfied. In this case, the position on which the total of entry-side and exit-side bending forces acts can be set within a range of 0 to L1/2 ≤ Ls/4, and thus, significant deterioration of the lifetime of the bearing 790 can be suppressed.
In addition, the upper-work-roll bearing-housing backlash elimination cylinder 760 is positioned at the middle of the section Ls and can press substantially the center of the possible position of the center of the bearing 790 when the bearing 790 shifts, so that an output force of the upper-work-roll bearing-housing backlash elimination cylinder 760 can be suppressed not to become excessively high. That is, a size increase of the upper-work-roll bearing-housing backlash elimination cylinder 760 can be suppressed, leading to an advantage that it becomes possible to accommodate the upper-work-roll bearing-housing backlash elimination cylinder 760 in the entry-side fixation member 702 more easily.

In addition, the output forces of the two upper-work-roll bending cylinders 740 disposed on the entry side can be made different from each other, and can have different values as shown in Table 1 below.

[Table 1]

Type	Position		Acting force	Section where there is bearing center position
Type	Position		Acting force	Ls
Bending force	Entry side	e1	Pe1	αe1×Pbe
		e2	Pe2	αe2×Pbe
		Total=Pe1+Pe2		Pbe
	Exit side			Pbd
	Total			Pbe+Pbd
Backlash elimination pressing force	Axial direction	g1	Pg1	Pg1

For example, when the center of the bearing of the work roll shifts within Ls, the upper-work-roll bending cylinder 740,e1 on the axially outer side is driven with an output force obtained by multiplying an entry-side bending force Pbe by a predetermined coefficient αe1. In addition, the upper-work-roll bending cylinder 740,e2 is driven with an output force obtained by multiplying the entry-side bending force Pbe by a predetermined coefficient αe2. Further, the work-roll bending cylinder 741 is driven with an output force Pbd.
At this time, αe1 and αe2 are selected such that the resultant force, Pe1 + Pe2 = Pbe, of the upper-work-roll bending cylinder 740,e1 and the upper-work-roll bending cylinder 740,e2 acts on the center of the bearing 790. Thereby, it is possible to cause the total of the entry-side and exit-side bending forces, Pbe + Pbd, to act on substantially the center of the bearing 790.
The upper-work-roll bearing-housing backlash elimination cylinder 760 is driven with the same output force Pg1.
Note that, while the description has been made regarding the case where the two upper-work-roll bending cylinder 740,e1 and upper-work-roll bending cylinder 740,e2 disposed on the entry side are driven, it is possible that either one of the upper-work-roll bending cylinder 740e1 and the upper-work-roll bending cylinder 740e2 is driven according to the position to which the bearing 790 has shifted. This can also minimize a misalignment between the axial center of the bearing 790 and the bending force acting position.
Next, the manufacturing method for the rolling mill according to the present embodiment and the modification method for an existing rolling mill are explained.
First, the manufacturing method for the rolling mill illustrated in FIG. 3 to FIG. 7 is explained simply.
First, each mechanism included in the rolling mill and described with reference to FIG. 3 to FIG. 7 is prepared. Each mechanism can be prepared by various methods as appropriate according to the specifications.
Next, the prepared mechanisms are assembled. At this time, in the present embodiment, the upper-work-roll bending cylinders 740, the lower-work-roll bending cylinders 744, and the upper-work-roll bearing-housing backlash elimination cylinder 760 and lower-work-roll bearing-housing backlash elimination cylinder 762 that apply pressing forces in the rolling direction to the bearing housings 712 and 713 are disposed axially on the entry side in the rolling direction. Along with this, on the exit side in the rolling direction, the work-roll bending cylinder 741 is disposed, and the members 712A and 713A that receive bending forces from the work-roll bending cylinder 741 are disposed between the work-roll bending cylinder 741 and the respective bearing housings 712 and 713.
Thereafter, adjustment work and inspections are implemented as appropriate, and then it becomes ready to perform operation.
Next, the method for modifying an existing rolling mill to a rolling mill like the one illustrated in FIG. 3 to FIG. 7 is explained.
While the present embodiment describes as an example a case where a rolling mill as described in Patent Documents 1 and 2 above is adopted as an existing rolling mill, the rolling mill including an axially shiftable work roll, bearing housings that are shiftable along with the work roll and receive loads from the work roll, and bearing-center-pressing bending-force applying devices (bending devices) that apply bending forces vertically to the bearing housings to thereby cause the work roll to perform bending on the entry and exit sides in the rolling direction, existing rolling mills are not limited to this.
When a modification is to be performed, first, the bearing-center-pressing bending-force applying device on either one of the entry and exit sides in the rolling direction is removed from the rolling mill.
Thereafter, at the place where the bearing-center-pressing bending-force applying device has been removed earlier, a new bending device having the bending cylinder 741 and the members 712A and 713A that receive bending forces from the bending cylinder 741 between the bending cylinder 741 and the respective bearing housings 712 and 713, or a new bending device having the bending cylinder 741, like the one illustrated in FIG. 3 to FIG. 7, is attached.
In addition, either before or after the attachment of the new bending device, the bearing-center-pressing bending-force applying device on the opposite side to the side where the new bending device is or is to be attached can be removed from the rolling mill, and also, at the place where this bearing-center-pressing bending-force applying device has been removed, a backlash elimination bending device having the bending cylinders 740 and the backlash elimination cylinder 760 can be attached.
Parts to be replaced at the time of the removal and attachment are not limited only to bending devices, and modification can also be performed for various types of members such as lines for supplying a hydraulic fluid to cylinders in the bending devices, the entry-side fixation member 702 and the exit-side fixation member 703 around the bending devices, the controller 80, control programs, or wires for control.
Next, advantages of the present embodiment are explained.
The rolling mill according to the first embodiment of the present invention described above includes the members 712A and 713A that are disposed between the bending cylinder 741 and the respective bearing housings 712 and 713 and receive bending forces from the bending cylinder 741, the bending cylinders 740 and 744 and the backlash elimination cylinder 760 are disposed axially on one of the entry and exit sides in the rolling direction, and the bending cylinder 741 and the members 712A and 713A are disposed on the other of the entry and exit sides in the rolling direction.
Such a structure provides an advantage that, even in a case where a bending device like a bearing-center-pressing bending-force applying device that is likely to have a larger size is included, it is possible to dispose a backlash elimination cylinder that solves a horizontal backlash (gap) of a roll bearing housing generated during rolling, without causing a size increase of the device.
In addition, the members 712A and 713A are configured to be, at least partially, axially shiftable along with the bearing housings 712 and 713. As mentioned above, the members 712A and 713A receive bending forces from the bending cylinder and cause the bending forces to effectively act on the bearing housings 712 and 713, and thus, the positions of the members 712A and 713A influence the positions of the bearing housings 712 and 713 on which the bending forces act. In addition, because the members 712A and 713A are shiftable along with the bearing housings 712 and 713 that are displaced along with roll shifting, the displacement of the members 712A and 713A and the displacement of the bearing housings 712 and 713 are synchronized, so that it is possible to make it easier to cause the bending forces to act on desired positions of the bearing housings 712 and 713, without being influenced by the roll shifting. Accordingly, it is possible to make it much easier to cause the bending forces to act on the center of the bearing 790.
Further, because the members 712A and 713A each have therein a portion whose horizontal cross-sectional area is larger on the side of the bearing housing 712 or 713 than on the side of the work-roll bending cylinder 741, it can be suppressed that the bending forces from the bending cylinder act locally on the bearing housings 712 and 713, particularly on flange portions of the bearing housings 712 and 713. Accordingly, it is possible to make it unlikely for the bearing housings 712 and 713 to be damaged, and the lifetime of the bearing housings 712 and 713 can be extended.
In addition, also because the members 712A and 713A each have therein a portion whose axial length is longer on the side of the bearing housing 712 or 713 than on the side of the work-roll bending cylinder 741, it can be suppressed that the bending forces act locally on the bearing housings 712 and 713, particularly on flange portions of the bearing housings 712 and 713. In addition, in the case where the members 712A and 713A are shiftable along with the bearing housings 712 and 713, it is necessary to secure in the members 712A and 713A large areas for allowing the bending forces to act, and this influences the size of the structure around the first cylinder. In this sense, by making the axial length shorter on the side of the first cylinder, a size increase of the structure around the first cylinder can be suppressed, leading to an advantage that a size increase of the bending device can be suppressed more easily.
Further, the two bending cylinders 740 and the one backlash elimination cylinder 760 are disposed on either of the entry and exit sides in the rolling direction, and particularly, the bending cylinder 740, the backlash elimination cylinder 760, and the bending cylinder 740 are disposed axially in this order on either one of the entry and exit sides in the rolling direction. The members 712A and 713A are configured such that the axial positions thereof are shiftable between the two bending cylinders 740 when seen from the entry or exit side in the rolling direction. With such configurations, the bending cylinder disposed on one side in the rolling direction can generate bending forces at least at an axial position ranging from one of the two bending cylinders to the other. Accordingly, it is possible to make it easier to cause the resultant force of the bending forces together with the bending forces of the bending cylinders on the other side in the rolling direction to act on the bearing center. In addition, because the axial range on which the backlash elimination cylinder can cause an appropriate pressing force to act and the shiftable range of the bearing center become substantially the same, it is not necessary to use a backlash elimination cylinder whose output force is larger than required, and a size increase of the device can be suppressed more easily.
In addition, the controller 80 that drives the bending cylinders 740 and 741 is further included. The axial center position of the bearing that supports the work roll 710 is disposed between the two bending cylinders 740 disposed on one side, and the controller 80 drives either one of the two bending cylinders 740 disposed on the one side and also drives the bending cylinder 741 disposed on the other side when bending of the work roll 710 is performed. Accordingly, it is possible to cause the resultant bending force to act on the vicinity of the bearing center with use of two bending cylinders per one bearing 790.
Furthermore, the controller 80 performs control such that the difference between the total output force of at least one bending cylinder 740 disposed on one side and the output force of the bending cylinder 741 disposed on the other side is kept within a predetermined range at the time when bending of the work roll 710 is performed. Accordingly, it is possible to cause substantially equal bending forces to act on the entry and exit sides of the bearing 790, leading to an advantage that the roll can be held stably.

A rolling mill, a manufacturing method for a rolling mill, and a modification method for a rolling mill according to a second embodiment of the present invention are explained with reference to FIG. 8. FIG. 8 is a plan view for explaining details of a work roll portion of the rolling mill according to the present second embodiment.
In the first embodiment described with reference to FIG. 3 to FIG. 7, the rolling mill has a configuration in which the two bending cylinders 740 and the one backlash elimination cylinder 760 are disposed on the entry side in the rolling direction on each of the drive and work sides of the work roll 710. In contrast to this, in the rolling mill according to the present embodiment illustrated in FIG. 8, one bending cylinder 740 and two backlash elimination cylinders 760 are disposed on the entry side.
Using the portion of the upper work roll 710 as an example for explanation, particularly, the upper-work-roll bending cylinder 740 is disposed at a position of L1 = Ls/2, and, on both sides thereof, an upper-work-roll bearing-housing backlash elimination cylinder 760,g1 and an upper-work-roll bearing-housing backlash elimination cylinder 760,g2 are disposed. Their output forces can be made equal values, for example, but can be made different values as described later.
As for the exit side in the rolling direction, similarly to the first embodiment, the work-roll bending cylinder 741 is disposed on the rolled material 5 exit side on each of the drive and work sides of the upper work roll 710.
When the center of the bearing 790 in the bearing housings 712 and 713 shifts within the section Ls, if L1 = Ls/2 is satisfied, the position on which the total of entry-side and exit-side bending forces acts can be set within a range of 0 to L1/2 = Ls/4. Because it is possible to cause the bending forces to act on a position within Ls/4 from the center of the bearing 790, the lifetime of the bearing is not deteriorated significantly.

In addition, the output forces of the two upper-work-roll bearing-housing backlash elimination cylinders 760 disposed on the entry side can be made different from each other, and can have different values as shown in Table 2 below.

[Table 2]

Type	Position		Acting force	Section where there is bearing center position
Type	Position		Acting force	Ls
Bending force	Entry side		Pbe	Pbe
	Exit side		Pbd	Pbd
	Total			Pbe+Pbd
Backlash elimination pressing force	Axial direction	g1	Pg1	γ1×Pg
	Axial direction	g2	Pg2	γ2×Pg
	Total output force =Pg1+Pg2			Pg

For example, when the center of the bearing of the work roll shifts within Ls, the upper-work-roll bending cylinder 740 is driven with an output force Pbe, and the work-roll bending cylinder 741 is driven with an output force Pbd.
At this time, a backlash elimination pressing force Pg1 of the upper-work-roll bearing-housing backlash elimination cylinder 760,g1 on the axially outer side is set to γ1 × Pg obtained by multiplying an output force Pg by a predetermined coefficient γ1, and a backlash elimination pressing force Pg2 of the upper-work-roll bearing-housing backlash elimination cylinder 760,g2 is set to γ2 × Pg obtained by multiplying the output force Pg by a predetermined coefficient γ2.
At this time, γ1 and γ2 are selected such that the resultant force, Pg1 + Pg2 = Pg, of the upper-work-roll bearing-housing backlash elimination cylinder 760,g1 and the upper-work-roll bearing-housing backlash elimination cylinder 760,g2 is caused to act on the center of the bearing 790. Accordingly, it is possible to cause the total of the entry-side and exit-side backlash elimination pressing forces to act on substantially the center of the bearing 790.
In other respects, the configurations and operations are substantially the same as those of the rolling mill, the manufacturing method for a rolling mill, and the modification method for a rolling mill according to the first embodiment described before, and detailed explanation thereof is omitted.
The rolling mill, the manufacturing method for a rolling mill, and the modification method for a rolling mill according to the second embodiment of the present invention also make it possible to attain advantages substantially similar to the advantages attained by the rolling mill, the manufacturing method for a rolling mill, and the modification method for a rolling mill according to the first embodiment described before.

A rolling mill, a manufacturing method for a rolling mill, and a modification method for a rolling mill according to a third embodiment of the present invention are explained with reference to FIG. 9 to FIG. 11. FIG. 9 is a front view for explaining an overview of a rolling mill according to the present third embodiment, FIG. 10 is a figure corresponding to a cross-section taken along D-D' in FIG. 9, and FIG. 11 is a plan view for explaining details of a work roll portion.
As illustrated in FIG. 9 and FIG. 10, in the rolling mill according to the present embodiment, an upper-work-roll bending cylinder 740A disposed in the entry-side fixation member 702 and an upper-work-roll bending cylinder 741A disposed in the exit-side fixation member 703 support the upper-work-roll bearing housing 712 on the upper side of the rolled material 5 on each of the work and drive sides.
In this configuration, on the entry side in the rolling direction, the vertical positions of the upper-work-roll bending cylinder 740A and a lower-work-roll bending cylinder 744A are deviated from each other in the axial direction, and are disposed in a staggered manner. The vertical positions of the upper-work-roll bearing-housing backlash elimination cylinder 760 and the lower-work-roll bearing-housing backlash elimination cylinder 762 coincide with each other.
In addition, a member 712B receiving a bending force from the upper-work-roll bending cylinder 740A is disposed between the upper-work-roll bending cylinder 740A and the bearing housing 712, and a member 713B receiving a bending force from the lower-work-roll bending cylinder 744A is disposed between the lower-work-roll bending cylinder 744A and the bearing housing 713.
On the lower side on each of the work and drive sides, the lower-work-roll bending cylinder 744A disposed in the entry-side fixation member 702 and a lower-work-roll bending cylinder 745A disposed in the exit-side fixation member 703 mentioned above support the lower-work-roll bearing housing 713.
Then, the vertical positions of the upper-work-roll bending cylinder 741A and the lower-work-roll bending cylinder 745A are deviated from each other in the axial direction, and are disposed in a staggered manner.
In addition, a member 712C receiving a bending force from the upper-work-roll bending cylinder 741A is disposed between the upper-work-roll bending cylinder 741A and the bearing housing 712, and a member 713C receiving a bending force from the lower-work-roll bending cylinder 745A is disposed between the lower-work-roll bending cylinder 745A and the bearing housing 713.
Also in such a structure, it is possible to cause the bending forces to act on substantially the center of the bearing 790. In addition, also at the time of backlash elimination, the substantial center of the possible position of the center of the bearing 790 displaced when the work roll 710 shifts can be pressed.
In other respects, the configurations and operations are substantially the same as those of the rolling mill, the manufacturing method for a rolling mill, and the modification method for a rolling mill according to the first embodiment described before, and detailed explanation thereof is omitted.
The rolling mill, the manufacturing method for a rolling mill, and the modification method for a rolling mill according to the third embodiment of the present invention also make it possible to attain advantages substantially similar to the advantages attained by the rolling mill, the manufacturing method for a rolling mill, and the modification method for a rolling mill according to the first embodiment described before.

Note that the present invention is not limited to the embodiments described above and includes various modification examples. The embodiments described above are explained in detail in order to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to those including all the configurations explained.
In addition, it is also possible to replace some of the configurations of an embodiment with configurations of another embodiment, and it is also possible to add a configuration of an embodiment to the configurations of another embodiment. Further, some of the configurations of each embodiment can also have other configurations additionally, be deleted, or be replaced with other configurations.
For example, while the above embodiments describe the cases where subject rolls are the work rolls 710 and 711, the rolling mill according to the present invention can also be applied to a rolling mill including six rolls. In this case, it is possible to adopt the structures described above also to intermediate rolls that support work rolls by being in contact with the work rolls.
In addition, while the first embodiment describes the case where the two upper-work-roll bending cylinders 740 are disposed on the entry side in the rolling direction on each of the work and drive sides, three or more bending cylinders can be disposed. Further, it is also possible to dispose two or more backlash elimination cylinders 760.
Similarly, in the second embodiment and the third embodiment, it is also possible to increase the numbers of bending cylinders 740 and backlash elimination cylinders 760 on each of the work and drive sides.

Description of Reference Characters

1: Rolling facility
5: Rolled material
10: First stand (rolling mill)
20: Second stand (rolling mill)
30: Third stand (rolling mill)
40: Fourth stand (rolling mill)
50: Fifth stand (rolling mill)
60: Sixth stand (rolling mill)
70: Seventh stand (rolling mill)
80: Controller
700: Housing
702: Entry-side fixation member
703: Exit-side fixation member
710: Upper work roll (roll)
711: Lower work roll (roll)
712: Upper-work-roll bearing housing
712A, 712B, 712C: Member
713: Lower-work-roll bearing housing
713A, 713B, 713C: Member
715, 716: Shift cylinder
730: Upper backup roll
731: Lower backup roll
732: Upper-backup roll bearing housing
733: Lower-backup roll bearing housing
740, 740A: Upper-work-roll bending cylinder (first cylinder)
741: Work-roll bending cylinder (first cylinder)
741A: Upper-work-roll bending cylinder (first cylinder)
744, 744A: Lower-work-roll bending cylinder (first cylinder)
745A: Lower-work-roll bending cylinder (first cylinder)
760: Upper-work-roll bearing-housing backlash elimination cylinder (second cylinder)
762: Lower-work-roll bearing-housing backlash elimination cylinder (second cylinder)
780: Upper-backup roll bearing-housing backlash elimination cylinder
782: Lower-backup roll bearing-housing backlash elimination cylinder
790: Bearing
1712: Upper-work-roll bearing housing
1715: Shift cylinder
1740, 1741: Bearing-center-pressing bending-force applying device
1790: Bearing
1760: Upper-work-roll bearing-housing backlash elimination cylinder

Claims

A rolling mill (10, 20, 30, 40, 50) comprising:
a roll (710, 711) configured to be shifted in an axial direction;

a bearing housing (712, 713, 732, 733) configured to be shifted in a roll-axis direction along with the roll, and configured to receive a load from the roll;

first cylinders (740, 740A, 741, 741A, 744, 744A, 745A) configured to apply bending force vertically to the bearing housing to cause the roll to perform bending, and

a member (712A, 712B, 712C, 713A, 713B, 713C) that is disposed between one of the first cylinders and the bearing housing and configured to receive a bending force from the first cylinder,

characterized in that

the rolling mill comprises a second cylinder (760, 762) configured to apply a pressing force in a rolling direction to the bearing housing,

another one of the first cylinders and the second cylinder are disposed axially on one of an entry side and an exit side in the rolling direction, and

the one first cylinder and the member are disposed on the other of the entry and exit sides in the rolling direction.
The rolling mill (10, 20, 30, 40, 50) according to claim 1, wherein the member (712A, 712B, 712C, 713A, 713B, 713C) is configured to be, at least partially, axially shiftable along with the bearing housing (712, 713, 732, 733).
The rolling mill (10, 20, 30, 40, 50) according to claim 1 or 2, wherein the member (712A, 712B, 712C, 713A, 713B, 713C) has therein a portion whose horizontal cross-sectional area is larger on a side of the bearing housing (712, 713, 732, 733) than on a side of the first cylinder (740, 740A, 741, 741A, 744, 744A, 745A).
The rolling mill (10, 20, 30, 40, 50) according to any one of claims 1 to 3, wherein the member (712A, 712B, 712C, 713A, 713B, 713C) has therein a portion whose axial length is longer on a side of the bearing housing (712, 713, 732, 733) than on a side of the first cylinder (740, 740A, 741, 741A, 744, 744A, 745A).
The rolling mill (10, 20, 30, 40, 50) according to any one of claims 1 to 4, wherein two first cylinders (740) and one second cylinder (760) or one first cylinder (740) and two second cylinders (760) are disposed on either one of the entry and exit sides in the rolling direction.
The rolling mill (10, 20, 30, 40, 50) according to claim 5, wherein
the first cylinder (740), the second cylinder (760), and the first cylinder (740) are disposed axially in this order on either one of the entry and exit sides in the rolling direction, and

the member (712A, 712B, 712C, 713A, 713B, 713C) is configured such that an axial position thereof is shiftable between the two first cylinders when seen from the entry or exit side in the rolling direction.
The rolling mill (10, 20, 30, 40, 50) according to claim 5, further comprising:
a controller (80) that drives the first cylinders (740), wherein

the controller is configured to drive either one of the two first cylinders disposed on the one side and also drive the first cylinder disposed on the other side when an axial center position of a bearing that supports the roll is disposed between the two first cylinders disposed on the one side, and bending of the roll (710, 711) is performed.
The rolling mill (10, 20, 30, 40, 50) according to claim 1, further comprising:
a controller (80) that drives the first cylinders (740, 740A, 741, 741A, 744, 744A, 745A), wherein

the controller is configured to perform control such that a difference between a total output force of the at least one first cylinder disposed on the one side and an output force of the first cylinder disposed on the other side is kept within a predetermined range when bending of the roll (710, 711) is performed.
A manufacturing method for a rolling mill (10, 20, 30, 40, 50), the rolling mill including
a roll (710, 711) configured to be shifted in an axial direction,

a bearing housing (712, 713, 732, 733) configured to be shifted in a roll-axis direction along with the roll, and configured to receive a load from the roll, and

first cylinders (740, 740A, 741, 741A, 744, 744A, 745A) configured to apply bending force vertically to the bearing housing to cause the roll to perform bending,

the manufacturing method comprising:
a step of axially disposing, on one of an entry side and an exit side in a rolling direction, one of the first cylinders and a second cylinder (760, 762) configured to apply a pressing force in the rolling direction to the bearing housing; and

a step of disposing, on the other of the entry and exit sides in the rolling direction, another one of the first cylinders and a member (712A, 712B, 712C, 713A, 713B, 713C) that is disposed between the first cylinder and the bearing housing and is configured to receive a bending force from the first cylinder.
A modification method for a rolling mill (10, 20, 30, 40, 50), the rolling mill including
a roll that (710, 711) configured to be shifted in an axial direction,

a bearing housing (712, 713, 732, 733) configured to be shifted in a roll-axis direction along with the roll, and configured to receive a load from the roll, and

bending devices that are disposed on an entry side and an exit side in a rolling direction and have bending cylinders (740, 740A, 741, 741A, 744, 744A, 745A) configured to apply bending force vertically to the bearing housing to cause the roll to perform bending,

the modification method comprising:
a step of removing the bending device on either one of the entry and exit sides in the rolling direction from the rolling mill;

a step of attaching, to the place from which the bending device has been removed, a new bending device having a bending cylinder (741) and members (712A, 713A) configured to receive bending forces from the bending cylinder between the bending cylinder and the respective one of the bearing housings;

a step, either before or after the attachment of the new bending device, of removing the bending device on the other one of the entry and exit sides in the rolling direction from the rolling mill; and

a step of attaching, to the place from which the bending device on the other one of the entry and exit side has been removed, a backlash elimination bending device having a bending cylinder (740) configured to apply bending force vertically to the bearing housing and a backlash elimination cylinder (760) configured to apply a pressing force in the rolling direction to the bearing housing.