ROLLING MILL AND ROLLING METHOD

Abstract

Provided are a plurality of hydraulic cylinders including drive side shift cylinders and work side shift cylinders all configured so as to apply force in an axial direction to a top work roll. The position of the top work roll in the axial direction is held by the drive side shift cylinders and the work side shift cylinders being moved in respective axial directions. The hydraulic circuit is configured such that, after the hydraulic circuit holds the position of the top work roll in the axial direction, in a case where the hydraulic cylinders from between the drive side shift cylinders or between the work side shift cylinders are put, by external force acting upon the top work roll, into a state in which the one hydraulic cylinder applies force in the axial direction to the top work roll, the other hydraulic cylinders are moved in the opposite direction.

Claims

1. A rolling mill comprising: a mill roll; a plurality of hydraulic cylinders including a drive side hydraulic cylinder that is configured to apply force in an axial direction to the mill roll and is provided on a drive side of the mill roll, and a work side hydraulic cylinder that is configured to apply force in the axial direction and is provided on a work side of the mill roll; and a hydraulic circuit configured to send a hydraulic oil to the plurality of hydraulic cylinders so that the drive side hydraulic cylinder and the work side hydraulic cylinder move in the axial direction to hold a position of the mill roll in the axial direction, wherein the hydraulic circuit is configured such that after the hydraulic circuit holds a position of the mill roll in the axial direction, in a case where only a hydraulic cylinder on one side between the drive side hydraulic cylinder and the work side hydraulic cylinder becomes a state of applying force in the axial direction to the mill roll due to external force received by the mill roll, a hydraulic cylinder on another side between the drive side hydraulic cylinder and the work side hydraulic cylinder moves in a direction opposite to the hydraulic cylinder on the one side.

2. The rolling mill according to claim 1, wherein in the hydraulic circuit, a drive-side strip-side hydraulic oil chamber and a work-side side-opposite-to-strip hydraulic oil chamber are connected to each other through a pipe and a drive-side side-opposite-to-strip hydraulic oil chamber and a work-side strip-side hydraulic oil chamber are connected to each other through a pipe so that each of the drive side hydraulic cylinder and the work side hydraulic cylinder applies force to the mill roll in a same direction.

3. The rolling mill according to claim 2, wherein the hydraulic circuit is configured such that when a hydraulic cylinder on one side between the drive side hydraulic cylinder and the work side hydraulic cylinder moves by a predetermined stroke, a hydraulic cylinder on another side between the drive side hydraulic cylinder and the work side hydraulic cylinder also moves in an opposite direction by the predetermined stroke without changing an amount of oil in the coupled pipes.

4. The rolling mill according to claim 1, wherein the drive side hydraulic cylinder and the work side hydraulic cylinder are double rod cylinders, a drive-side strip-side hydraulic oil chamber and a drive-side side-opposite-to-strip hydraulic oil chamber have a same cross-sectional area in a direction in which force of the hydraulic oil is applied, a work-side strip-side hydraulic oil chamber and a work-side side-opposite-to-strip hydraulic oil chamber have a same cross-sectional area in a direction in which force of the hydraulic oil is applied, and the drive-side strip-side hydraulic oil chamber and the work-side side-opposite-to-strip hydraulic oil chamber are connected to each other through a pipe, and the drive-side side-opposite-to-strip hydraulic oil chamber and the work-side strip-side hydraulic oil chamber are connected to each other through a pipe.

5. The rolling mill according to claim 1, wherein the drive side hydraulic cylinder and the work side hydraulic cylinder are single rod cylinders, orientations of a drive side hydraulic cylinder rod and a work side hydraulic cylinder rod are same, a drive-side strip-side hydraulic oil chamber and a work-side side-opposite-to-strip hydraulic oil chamber are connected to each other through a pipe, and have a same cross-sectional area in a direction in which force of the hydraulic oil is applied, and a drive-side side-opposite-to-strip hydraulic oil chamber and a work-side strip-side hydraulic oil chamber are connected to each other through a pipe, and have a same cross-sectional area in a direction in which force of the hydraulic oil is applied.

6. The rolling mill according to claim 1, wherein the drive side hydraulic cylinder and the work side hydraulic cylinder are single rod cylinders, orientations of a drive side hydraulic cylinder rod and a work side hydraulic cylinder rod are opposite to each other, two or more single rod intermediate cylinders are provided, a drive-side rod-side hydraulic oil chamber and a first intermediate cylinder rod side hydraulic oil chamber are connected to each other through a pipe, a drive-side head-side hydraulic oil chamber and a second intermediate cylinder head side hydraulic oil chamber are connected to each other through a pipe, a work-side rod-side hydraulic oil chamber and a second intermediate cylinder rod side hydraulic oil chamber are connected to each other through a pipe, a work-side head-side hydraulic oil chamber and a first intermediate cylinder head side hydraulic oil chamber are connected to each other through a pipe, and a ratio of a cross sectional area of the drive-side rod-side hydraulic oil chamber to a cross sectional area of the drive-side head-side hydraulic oil chamber in a direction in which force of the hydraulic oil is applied, a ratio of a cross sectional area of the work-side rod-side hydraulic oil chamber to a cross sectional area of the work-side head-side hydraulic oil chamber in a direction in which force of the hydraulic oil is applied, a ratio of a cross sectional area of the first intermediate cylinder rod side hydraulic oil chamber to a cross sectional area of the first intermediate cylinder head side hydraulic oil chamber in a direction in which force of the hydraulic oil is applied, and a ratio of a cross sectional area of the second intermediate cylinder rod side hydraulic oil chamber to a cross sectional area of the second intermediate cylinder head side hydraulic oil chamber in a direction in which force of the hydraulic oil is applied are same.

7. The rolling mill according to claim 6, wherein a drive side hydraulic cylinder rod and a work-side hydraulic cylinder rod are configured to face outward in the axial direction.

8. The rolling mill according to claim 1, wherein the drive side hydraulic cylinder and the work-side hydraulic cylinder are provided on each of an entry side and an exit side of the rolling mill, and pipes for coupling corresponding hydraulic oil chambers on the entry side and the exit side are provided.

9. The rolling mill according to claim 1, wherein a controller for controlling drive of the plurality of hydraulic cylinders is provided, and the controller is configured to be capable of shifting the mill roll in the axial direction by causing the drive side hydraulic cylinder and the work-side hydraulic cylinder to be driven.

10. The rolling mill according to claim 1, wherein a horizontal direction actuator for adjusting an angle of the mill roll in a horizontal direction is provided.

11. A rolling method for a rolled metal strip by a rolling mill including: a mill roll; a plurality of hydraulic cylinders including a drive side hydraulic cylinder that is configured to apply force in an axial direction to the mill roll and is provided on a drive side of the mill roll, and a work side hydraulic cylinder that is configured to apply force in the axial direction and is provided on a work side of the mill roll; and a hydraulic circuit configured to send hydraulic oil to the plurality of hydraulic cylinders so that the drive side hydraulic cylinder and the work side hydraulic cylinder move in the axial direction to hold a position of the mill roll in the axial direction, the method comprising: rolling the rolled metal strip by configuring the hydraulic circuit such that after the hydraulic circuit holds a position of the mill roll in the axial direction, in a case where only a hydraulic cylinder on one side between the drive side hydraulic cylinder and the work side hydraulic cylinder becomes a state of applying force in the axial direction to the mill roll due to external force received by the mill roll, a hydraulic cylinder on another side between the drive side hydraulic cylinder and the work side hydraulic cylinder moves in a direction opposite to the hydraulic cylinder on the one side.

12. The rolling method according to claim 11, wherein the rolled metal strip is rolled by configuring the hydraulic circuit such that a drive-side strip-side hydraulic oil chamber and a work-side side-opposite-to-strip hydraulic oil chamber are connected to each other through a pipe and a drive-side side-opposite-to-strip hydraulic oil chamber and a work-side strip-side hydraulic oil chamber are connected to each other through a pipe so that each of the drive side hydraulic cylinder and the work side hydraulic cylinder applies force to the mill roll in a same direction.

13. The rolling method according to claim 12, wherein the rolled metal strip is rolled by configuring the hydraulic circuit such that when a hydraulic cylinder on one side between the drive side hydraulic cylinder and the work side hydraulic cylinder moves by a predetermined stroke, a hydraulic cylinder on another side between the drive side hydraulic cylinder and the work side hydraulic cylinder also moves in an opposite direction by the predetermined stroke without changing an amount of oil in the coupled pipes.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is a diagram for depicting an outline of a rolling facility provided with a rolling mill of a first embodiment.

[0013] FIG. 2 is a front view for explaining an outline of the rolling mill of the first embodiment.

[0014] FIG. 3 is an arrow A-A view of FIG. 2.

[0015] FIG. 4 is a schematic view for explaining a problem of the present invention.

[0016] FIG. 5 is a schematic view for explaining a problem of the present invention.

[0017] FIG. 6 is a schematic view for explaining a problem of the present invention.

[0018] FIG. 7 is a plan view for explaining the details of a top work roll part in the rolling mill of the first embodiment.

[0019] FIG. 8 is a plan view for explaining the details of the top work roll part in the rolling mill of the first embodiment.

[0020] FIG. 9 is a plan view for explaining the details of the top work roll part in the rolling mill of the first embodiment.

[0021] FIG. 10 is a plan view for explaining the details of a top work roll part in a rolling mill of a modified example of the first embodiment.

[0022] FIG. 11 is a plan view for explaining the details of a top work roll part in a rolling mill of a second embodiment.

[0023] FIG. 12 is a plan view for explaining the details of a top work roll part in a rolling mill of a third embodiment.

[0024] FIG. 13 is a plan view for explaining the details of the top work roll part in the rolling mill of the third embodiment.

[0025] FIG. 14 is a plan view for explaining the details of a top work roll part in a rolling mill of a fourth embodiment.

MODES FOR CARRYING OUT THE INVENTION

[0026] Hereinafter, embodiments of a rolling mill and a rolling method of the present invention will be described using the drawings.

[0027] It should be noted that in the drawings used in the specification, the same or corresponding constitutional elements will be denoted by the same or similar reference numerals, and repeated description of these constitutional elements will be omitted in some cases.

[0028] In addition, the thrust resistance force in the specification is force acting on each roll of the rolling mill and a bearing box thereof in the roll axial direction during rolling or when shifting during rolling, means force acting on a device supporting the force, and has the same meaning as the thrust force. The thrust reaction force is force that is generated from the device supporting the thrust resistance force and means force in the direction opposite to the thrust resistance force having the same magnitude.

First Embodiment

[0029] A first embodiment of a rolling mill and a rolling method of the present invention will be described using FIG. 1 to FIG. 10.

[0030] First, an outline of a rolling facility provided with the rolling mill of the present embodiment will be described using FIG. 1 to FIG. 3. FIG. 1 is a diagram for depicting an outline of the rolling facility provided with the rolling mill of the first embodiment, FIG. 2 is a front view for explaining an outline of the rolling mill, and FIG. 3 is an arrow A-A view of FIG. 2.

[0031] As depicted in FIG. 1, a rolling facility 1 is provided with a plurality of rolling mills for hot-rolling a rolled metal strip 5 into strips, and has a controller 80, and five rolling mill stands of a first rolling mill stand 30, a second rolling mill stand 40, a third rolling mill stand 50, a fourth rolling mill stand 60, and a fifth rolling mill stand 70 from the entry side of the rolled metal strip 5.

[0032] Among them, each of the first rolling mill stand 30, the second rolling mill stand 40, the third rolling mill stand 50, the fourth rolling mill stand 60, and the fifth rolling mill stand 70, and a part of the controller 80 that controls each rolling mill stand correspond to the rolling mill of the present invention.

[0033] It should be noted that the rolling facility 1 is not limited to the plurality of rolling mill stands such as the five rolling mill stands depicted in FIG. 1, but may be of one rolling mill stand. In addition, since the temperature of the rolled metal strip at the time of rolling is not limited, a rolling facility for cold rolling may be used.

[0034] Next, a part of an outline of the rolling mill of the present invention will be described using FIG. 2. It should be noted that although the fifth rolling mill stand 70 depicted in FIG. 1 will be described as an example in FIG. 2 and thereafter, the rolling mill of the present invention can be applied to any rolling mill stand among the first rolling mill stand 30, the second rolling mill stand 40, the third rolling mill stand 50, and the fourth rolling mill stand 60 depicted in FIG. 1.

[0035] In FIG. 2, the fifth rolling mill stand 70, which is a rolling mill of the present embodiment, is a six-high rolling mill for rolling the rolled metal strip 5, and has a housing 700, the controller 80, and a hydraulic device 90.

[0036] The housing 700 is provided with a top work roll 710 and a bottom work roll 711, and a top intermediate roll 720 and a bottom intermediate roll 721 that contact the top work roll 710 and the bottom work roll 711 to support them, respectively. Further, a top back-up roll 730 and a bottom back-up roll 731 that contact the top intermediate roll 720 and the bottom intermediate roll 721 to support them, respectively.

[0037] Among them, a mill roll in the present invention corresponds to any of the top work roll 710, the bottom work roll 711, the top intermediate roll 720, the bottom intermediate roll 721, the top back-up roll 730, and the bottom back-up roll 731 described above. It should be noted that in the case of the rolling mill having no intermediate rolls such as the first rolling mill stand 30 or the second rolling mill stand 40, the top and bottom work rolls and the top and bottom back-up rolls correspond to the mill rolls.

[0038] Among these rolls, a radial bearing 790A (see FIG. 7) that shifts in the axial direction of the roll together with the top work roll 710 and receives a load from the roll is provided on the work side at the end of the top work roll 710 in the axial direction, and the radial bearing 790A is supported by a top work side bearing box 712A. Similarly, a radial bearing 790B (see FIG. 7) that shifts in the axial direction of the roll together with the top work roll 710 and receives a load from the roll is provided on the drive side, and the radial bearing 790B is supported by a top drive side bearing box 712B. Here, the radial bearing 790A on the work side and the radial bearing 790B on the drive side are configured to be capable of supporting not only roll bending force acting in the perpendicular direction but also thrust force acting in the roll axial direction.

[0039] Similarly, bearings (omitted for convenience of illustration) are also provided in the bottom work roll 711 on both the drive side and the work side at ends in the axial direction, and these bearings are supported by bottom work roll bearing boxes 713 (a bearing box 713A on the work side and a bearing box 713B on the drive side).

[0040] In the present embodiment, the top work roll 710 is configured to be shiftable in the roll axial direction by a shift cylinder 715 as depicted in FIG. 3 via the top work side bearing box 712A on the work side and the top drive side bearing box 712B on the drive side. Similarly, the bottom work roll 711 is also configured to be shiftable in the roll axial direction by a shift cylinder 717 as depicted in FIG. 3 via the bearing box 713A on the work side and the bearing box 713B on the drive side.

[0041] In addition, as depicted in FIG. 3, tapered portions are provided at the ends of the top work roll 710 and the bottom intermediate roll 721 on the work side and at the ends of the bottom work roll 711 and the top intermediate roll 720 on the drive side, the top work roll 710 and the bottom work roll 711 are vertically point symmetrical, and the top intermediate roll 720 and the bottom intermediate roll 721 are vertically point symmetrical.

[0042] Referring back to FIG. 2, an entry side fixing member 702 is fixed to the housing 700 on the entry side of the rolled metal strip 5. An exit side fixing member 703 is fixed to the housing 700 on the exit side of the rolled metal strip 5 so as to face the entry side fixing member 702.

[0043] In the fifth rolling mill stand 70, as depicted in FIG. 2, the top work roll bearing box 712 is supported by two top work roll bending cylinders 740 and 742 provided at the entry side fixing member 702 in the axial direction of the roll and two top work roll bending cylinders 741 and 743 provided at the exit side fixing member 703 in the axial direction of the roll, on both the work side and the drive side.

[0044] Then, by appropriately driving these cylinders, the bending force is applied to the bearings of the top work roll 710 in the vertical direction.

[0045] Similarly, the bottom work roll bearing box 713 is supported by bottom work roll bending cylinders 744 and 746 provided at the entry side fixing member 702 and bottom work roll bending cylinders 745 and 747 provided at the exit side fixing member 703, on both the work side and the drive side, and by appropriately driving these cylinders, the bending force is applied to the bearings of the bottom work roll 711 in the vertical direction.

[0046] Among these cylinders, the top work roll bending cylinders 740 and 741 are disposed so as to apply the bending force, to the bearings of the top work roll 710 in contact with the rolled metal strip 5, to the increase side in the vertical direction (in the direction opposite to the rolled metal strip side). In addition, the top work roll bending cylinders 742 and 743 are disposed so as to apply the bending force, to the bearings, to the decrease side in the vertical direction (in the direction to the rolled metal strip side) that is opposite to the top work roll bending cylinders 740 and 741.

[0047] Similarly, the bottom work roll bending cylinders 744 and 745 are disposed so as to apply the bending force to the bearings of the bottom work roll 711 in contact with the rolled metal strip 5 to the increase side in the vertical direction. In addition, the bottom work roll bending cylinders 746 and 747 are disposed so as to apply the bending force to the bearings to the decrease side that is opposite to the bottom work roll bending cylinders 744 and 745.

[0048] Further, as depicted in FIG. 2, for the purpose of removing backlash, two top work roll bearing box backlash removing cylinders 760 are provided at the entry side fixing member 702 on the entry side of the rolled metal strip 5 in the axial direction of the roll so as to apply horizontal force, more specifically, pressing force in the rolling direction, to the top work roll 710 via a liner (not illustrated) of the top work roll bearing box 712.

[0049] Similarly, two bottom work roll bearing box backlash removing cylinders 762 are provided at the entry side fixing member 702 so as to apply pressing force in the rolling direction to the bottom work roll 711 via a liner of the bottom work roll bearing box 713.

[0050] These cylinders allow desired force to be applied to the top work roll 710 or the like in the direction orthogonal to the roll axial direction.

[0051] Further, as depicted in FIG. 2, a hydraulic cylinder 705A is provided in some cases on each of the drive side and the work side on the exit side of the housing 700, as a horizontal direction actuator for adjusting the angle of the top work roll 710 in the horizontal direction.

[0052] Similarly, a hydraulic cylinder 705B is provided in some cases on each of the drive side and the work side on the exit side of the housing 700, as a horizontal direction actuator for adjusting the angle of the bottom work roll 711 in the horizontal direction.

[0053] Further, hydraulic cylinders 705E and 705F are provided in some cases on each of the drive side and the work side on the exit side of the housing 700, and hydraulic cylinders 706C and 706D are provided in some cases on each of the drive side and the work side on the entry side of the housing 700, as horizontal direction actuators for adjusting the angle of each of the top intermediate roll 720, the bottom intermediate roll 721, the top back-up roll 730, and the bottom back-up roll 731 in the horizontal direction.

[0054] The hydraulic cylinders 705A, 705B, 705E, 705F, 706C, and 706D as the horizontal direction actuators are not limited to hydraulic cylinders, but other configurations such as worm gears can be adopted.

[0055] Bearings (not illustrated) are provided at the ends of the top intermediate roll 720 in the axial direction on both the drive side and the work side, and these bearings are supported by a top intermediate roll bearing box 722. Similarly, bearings (not illustrated) are also provided at the ends of the bottom intermediate roll 721 in the axial direction on both the drive side and the work side, and these bearings are supported by a bottom intermediate roll bearing box 723.

[0056] In the top intermediate roll 720, the top intermediate roll bearing box 722 is supported by a top intermediate roll bending cylinder 750 provided at the entry side fixing member 702 and a top intermediate roll bending cylinder 751 provided at the exit side fixing member 703 on both the work side and the drive side, and by appropriately driving these cylinders, the bending force is applied to the bearings to the increase side in the vertical direction.

[0057] Also in the bottom intermediate roll 721, the bottom intermediate roll bearing box 723 is supported by a bottom intermediate roll bending cylinder 752 provided at the entry side fixing member 702 and a bottom intermediate roll bending cylinder 753 provided at the exit side fixing member 703 on both the work side and the drive side, and by appropriately driving these cylinders, the bending force is applied to the bearings to the increase side in the vertical direction.

[0058] In addition, as depicted in FIG. 2, a top intermediate roll bearing box backlash removing cylinder 771 is provided at the housing 700 on the exit side so as to apply force in the horizontal direction to the top intermediate roll 720 via the top intermediate roll bearing box 722. Similarly, a bottom intermediate roll bearing box backlash removing cylinder 773 is provided at the housing 700 on the exit side so as to apply force in the horizontal direction to the bottom intermediate roll 721 via the bottom intermediate roll bearing box 723.

[0059] Further, bearings (not illustrated) are provided at the ends of the top back-up roll 730 in the axial direction on both the drive side and the work side, and these bearings are supported by a top back-up roll bearing box 732. Similarly, bearings (not illustrated) are also provided at the ends of the bottom back-up roll 731 in the axial direction on both the drive side and the work side, and these bearings are supported by a bottom back-up roll bearing box 733.

[0060] In addition, as depicted in FIG. 2, a top back-up roll bearing box backlash removing cylinder 780 is provided at the housing 700 on the entry side so as to apply force in the horizontal direction to the top back-up roll 730 via the top back-up roll bearing box 732. Similarly, a bottom back-up roll bearing box backlash removing cylinder 782 is provided at the housing 700 on the entry side so as to apply force in the horizontal direction to the bottom back-up roll 731 via the bottom back-up roll bearing box 733.

[0061] The hydraulic device 90 is connected to the respective hydraulic cylinders, such as the bending cylinders, the backlash removing cylinders, the shift cylinders 715 and 717, the hydraulic cylinders 705A, 705B, 705E, 705F, 706C, and 706D described above, or screw-down cylinders (not illustrated) that apply screw-down force for rolling the rolled metal strip 5 to the top work roll 710 and the bottom work roll 711, and the hydraulic device 90 is connected to the controller 80.

[0062] The controller 80 controls the operation of the hydraulic device 90 to supply and discharge pressure oil to/from the respective bending cylinders and the like described above, thereby driving and controlling the respective cylinders. Thus, the controller 80 is configured to be capable of shifting the top work roll 710 in the axial direction by causing, for example, a drive-side exit-side shift cylinder 715C (see FIG. 7) and a work-side exit-side shift cylinder 715B (see FIG. 7) to be driven.

[0063] Next, characteristic parts of the rolling mill and the rolling method in the present invention will be described using FIG. 4 to FIG. 6 by using a configuration related to the top work roll 710 among the respective rolls of the fifth rolling mill stand 70 as an example. It should be noted that the bottom work roll 711, the top intermediate roll 720, the bottom intermediate roll 721, the top back-up roll 730, and further, the bottom back-up roll 731, and the work rolls, the intermediate rolls, and the back-up rolls of other rolling mill stands can have the same configuration and method, and since the detailed configurations thereof are substantially the same, the description thereof will be omitted.

[0064] First, a problem of the present invention will be described using FIG. 4 to FIG. 6. FIG. 4 to FIG. 6 are schematic views for explaining a problem of the present invention.

[0065] FIG. 4 depicts a state at the time when an electromagnetic switching valve 810 is shifted in the drive side direction with b-excitation, the electromagnetic switching valve is then set to the neutral position to close a pilot check valve, and the shift operation in the drive side direction is stopped.

[0066] Here, in order to simplify the description, a roll set 710A including the top work roll 710 is expressed in a simplified and integrated form. The shift cylinders are installed on the entry side and the exit side, but since the entry side of the rolled metal strip 5 has substantially the same configuration as the exit side, only a drive-side exit-side shift cylinder 515C and a work-side exit-side shift cylinder 515B on the exit side are exemplified here.

[0067] As depicted in FIG. 4, the position in the axial direction of the roll set 710A is supported by the drive-side exit-side shift cylinder 515C via a drive side arm 714C on the drive side, and the position in the axial direction thereof is supported by the work-side exit-side shift cylinder 515B via a work side arm 714B on the work side.

[0068] The drive-side exit-side shift cylinder 515C is a single rod type cylinder, and is provided with a drive-side exit-side strip-side hydraulic oil chamber 523a on the rod side, a drive-side exit-side side-opposite-to-strip hydraulic oil chamber 523b on the head side, a rod 523c, a piston 523d, and the like.

[0069] The work-side exit-side shift cylinder 515B is also a single rod type cylinder, and is provided with a work-side exit-side strip-side hydraulic oil chamber 525a on the rod side, a work-side exit-side side-opposite-to-strip hydraulic oil chamber 525b on the head side, a rod 525c, a piston 525d, and the like.

[0070] In the hydraulic circuit depicted in FIG. 4, a pilot check valve 821 and a relief valve 811 are provided on a pressure line 803, and a pilot check valve 822 and a relief valve 812 are provided on a pressure line 804.

[0071] The pressure line 803 branches into a drive-side side-opposite-to-strip pressure line 505 and a work-side strip-side pressure line 506 on the cylinder side of the pilot check valve 821. The drive-side side-opposite-to-strip pressure line 505 is connected to the drive-side exit-side side-opposite-to-strip hydraulic oil chamber 523b, and the work-side strip-side pressure line 506 is connected to the work-side exit-side strip-side hydraulic oil chamber 525a.

[0072] The pressure line 804 branches into a drive-side strip-side pressure line 507 and a work-side side-opposite-to-strip pressure line 508 on the cylinder side of the pilot check valve 822. The drive-side strip-side pressure line 507 is connected to the drive-side exit-side strip-side hydraulic oil chamber 523a, and the work-side side-opposite-to-strip pressure line 508 is connected to the work-side exit-side side-opposite-to-strip hydraulic oil chamber 525b.

[0073] In the configuration depicted in FIG. 4, thrust resistance force Ht acting from the roll set 710A to the drive-side exit-side shift cylinder 515C and the work-side exit-side shift cylinder 515B when the roll set 710A is shifted to the drive side is expressed by H.sub.t=H.sub.d+H.sub.w. Here, Hw is force acting on the work side and Ha is force acting on the drive side.

[0074] Since the work-side exit-side side-opposite-to-strip hydraulic oil chamber 525b on the head side of the work-side exit-side shift cylinder 515B and the drive-side exit-side strip-side hydraulic oil chamber 523a on the rod side of the drive-side exit-side shift cylinder 515C are connected to each other through the drive-side strip-side pressure line 507 and the work-side side-opposite-to-strip pressure line 508, pressures p.sub.dr and p.sub.wh of the respective hydraulic oil chambers are equal.

[0075] However, since there is an area difference between a cross-sectional area A.sub.wh of the piston 525d that receives pressure on the head side of the work-side exit-side shift cylinder 515B and a cross-sectional area A.sub.dr of the piston 523d that receives pressure on the rod side of the drive-side exit-side shift cylinder 515C, an output Fw of the work-side exit-side shift cylinder 515B is larger than an output Fd of the drive-side exit-side shift cylinder 515C, the thrust resistance force acting from the roll set 710A on the shift cylinders has a relation of H.sub.w>H.sub.d, and the thrust resistance force Hw acting on a work side arm 714B has a larger value.

[0076] In such a configuration, a case where the roll set 710A itself moves to the drive side is considered. FIG. 5 depicts a state at the time when the shift position of the roll set 710A is determined, the pilot check valves 821 and 822 are closed, the shift operation is stopped, the roll set 710A itself then moves in the drive side direction, and first hits the drive side arm 714C.

[0077] On the work side, remaining backlash is present relative to the work side arm 714B. In an actual facility, backlash on the drive side and backlash on the work side are never exactly the same, and thus the remaining backlash does not become 0.

[0078] FIG. 6 depicts a state at the time when the roll set 710A further moves in the drive side direction from the state of FIG. 5, the remaining backlash generated on the work side becomes 0, and the movement of the roll set 710A in the drive side direction is stopped.

[0079] Here, a case where the area A.sub.dr of the drive-side exit-side strip-side hydraulic oil chamber 523a and the area A.sub.dh of the drive-side exit-side side-opposite-to-strip hydraulic oil chamber 523b of the drive-side exit-side shift cylinder 515C, and the area A.sub.wr of the work-side exit-side strip-side hydraulic oil chamber 525a and the area A.sub.wh of the work-side exit-side side-opposite-to-strip hydraulic oil chamber 525b of the work-side exit-side shift cylinder 515B have a relation of A.sub.wh=2A.sub.wr and A.sub.dh=2A.sub.dr is depicted.

[0080] When the roll set 710A first hits the drive side arm 714C, the drive-side exit-side shift cylinder 515C is pushed by the thrust resistance force of the roll set 710A, and a pressure of p.sub.dh is generated. In addition, p.sub.wr tries to become the same pressure as pan. Then, since A.sub.wr=A.sub.wh/2 is satisfied, p.sub.wr tries to become p.sub.wh=p.sub.wr/2 and p.sub.dr=p.sub.wh=p.sub.wr/2=p.sub.dh/2.

[0081] Here, since a relation of A.sub.dh p.sub.dh=H.sub.d+A.sub.drp.sub.dr is satisfied, when the above relation is substituted, a relation of A.sub.dhP.sub.dh=H.sub.d+(A.sub.dh/2)(p.sub.dh/2) is satisfied, and H.sub.d=A.sub.dhp.sub.dl3/4 is satisfied from this equation. That is, since pressure is also generated on the rod side of the drive-side exit-side shift cylinder 515C, only of the pushing force on the head side of the drive-side exit-side shift cylinder 515C can be supported.

[0082] Then, it is assumed that when the drive-side exit-side shift cylinder 515C is pushed and defeated by H.sub.d, the drive-side exit-side shift cylinder 515C is pushed and moved by 1.

[0083] In a case where the drive-side exit-side shift cylinder 515C is pushed by Ha and moved in the drive side direction, the work side arm 714B moves to the work side so as to reduce the remaining backlash.

[0084] If it is assumed that the drive-side exit-side shift cylinder 515C moves toward the drive side by 1, hydraulic oil flows from the drive-side exit-side side-opposite-to-strip hydraulic oil chamber 523b of the drive-side exit-side shift cylinder 515C to the work-side exit-side strip-side hydraulic oil chamber 525a of the work-side exit-side shift cylinder 515B. Therefore, although the piston 525d of the work-side exit-side shift cylinder 515B is to move toward the work-side exit-side side-opposite-to-strip hydraulic oil chamber 525b side by 2, the work-side exit-side side-opposite-to-strip hydraulic oil chamber 525b side can support the pushing force from the work-side exit-side strip-side hydraulic oil chamber 525a side with half the pressure on the work-side exit-side strip-side hydraulic oil chamber 525a side due to the area difference thereof, so that the work-side exit-side side-opposite-to-strip hydraulic oil chamber 525b side can move only by corresponding to the movement of 1 on the drive-side exit-side strip-side hydraulic oil chamber 523a side. Therefore, the work-side exit-side strip-side hydraulic oil chamber 525a side cannot move by 2 and only moves by . Thus, the hydraulic oil corresponding to (2-1/2) on the work-side exit-side strip-side hydraulic oil chamber 525a side flows out of the relief valve 811.

[0085] Specifically, if it is assumed that the drive-side exit-side shift cylinder 515C moves toward the drive side by 1, the work-side exit-side shift cylinder 515B moves toward the work side by . Accordingly, the remaining backlash becomes 0. Therefore, the drive side arm 714C moves in the drive side direction by of the remaining backlash, and the work side arm 714B moves in the work side direction by of the remaining backlash.

[0086] In addition, when the drive-side exit-side shift cylinder 515C is pushed by Ha and moved by 1 in the drive side direction, the rod side of the drive-side exit-side shift cylinder 515C also moves by 1, so that the head side of the work-side exit-side shift cylinder 515B moves by corresponds to the area ratio, and the rod side of the work-side exit-side shift cylinder 515B also moves by .

[0087] Therefore, the amount of hydraulic oil of A.sub.dh1A.sub.wr1/2=A.sub.dh3/4 is discharged from the relief valve 811. Then, when the drive side arm 714C and the work side arm 714B move by of the remaining backlash and of the remaining backlash, respectively, the drive-side exit-side shift cylinder 515C and the work-side exit-side shift cylinder 515B stop.

[0088] Since the work side arm 714B moves in the work side direction by of the remaining backlash, a position sensor 716 moves by of the remaining backlash.

[0089] The remaining backlash is the difference between the backlash on the work side and the backlash on the drive side, and in a case where the remaining backlash is approximately 1 mm, the position sensor 716 moves toward the work side by approximately 1 mm1/3=0.3 mm.

[0090] As described above, after the roll set 710A is moved in the drive side direction while receiving the thrust resistance force in the work side direction from the roll set 710A and the position of the roll set 710A is set, when the thrust resistance force in the drive side direction acts on the roll set 710A due to a change in conditions such as the rotation of the roll of the rolling mill to move only the roll set 710A in the drive side direction, the pressure rises above the set pressure (maximum pressure) of the relief valves 811 and 812 before the thrust resistance force is supported on both the drive side and the work side, and the hydraulic oil is discharged from the relief valves 811 and 812.

[0091] That is, when the thrust resistance force is supported only on the drive side if it can be supported only on the drive side, but only when the drive side is defeated, it is supported on both the drive side and the work side.

[0092] In this case, the pressure becomes equal to or higher than the maximum pressure while the hydraulic oil is discharged from the relief valves 811 and 812.

[0093] Therefore, there are problems that the thrust resistance force cannot be supported on both sides until the pressure becomes the set pressure of the relief valves 811 and 812, and when it is supported on both sides, the pressure becomes equal to or higher than the set pressure (maximum pressure).

[0094] Further, since the shift position of the roll set 710A deviates, it is necessary to frequently adjust the shift position.

[0095] In the above description, a case where the drive side arm 714C is hit first and the remaining backlash occurs on the work side has been explained, but a similar problem occurs even when the work side arm 714B is hit first and the remaining backlash occurs on the drive side.

[0096] In addition, although a problem caused when the direction of the thrust resistance force changes is explained in the above description, even when the length of the roll set 710A changes due to thermal expansion, it becomes a state similar to a state where the remaining backlash occurs on one side, and thus a similar problem occurs.

[0097] Next, a characteristic configuration of the present embodiment capable of solving such problems will be described using FIG. 7 to FIG. 9. FIG. 7 to FIG. 9 are plan views for explaining the details of the top work roll part in the rolling mill.

[0098] As depicted in FIG. 7, the entry side fixing member 702 on the work side is provided with a work-side entry-side shift cylinder 715A for applying force to the top work roll 710 in both the work side direction and the drive side direction via a work side arm 714A connected to the top work side bearing box 712A supporting the radial bearing 790A on the work side.

[0099] In addition, the exit side fixing member 703 on the work side is provided with a work-side exit-side shift cylinder 715B for applying force to the top work roll 710 in both the work side direction and the drive side direction via the work side arm 714B connected to the top work side bearing box 712A supporting the radial bearing 790A on the work side.

[0100] The position sensor 716 for detecting the position of the top work roll 710 in the roll axial direction is provided at the part of the work-side exit-side shift cylinder 715B. It should be noted that the position where the position sensor 716 is provided is not limited to this, but may be any position of other work-side entry-side shift cylinder 715A and drive side shift cylinders 715C and 715D. In addition, the number of positions is not necessary to be one, but may be two or more.

[0101] Similarly, the entry side fixing member 702 on the drive side is provided with a drive-side entry-side shift cylinder 715D for applying force to the top work roll 710 in both the work side direction and the drive side direction via a drive side arm 714D connected to the top drive side bearing box 712B supporting the radial bearing 790B on the drive side.

[0102] In addition, the exit side fixing member 703 on the drive side is provided with a drive-side exit-side shift cylinder 715C for applying force to the top work roll 710 in both the work side direction and the drive side direction via the drive side arm 714C connected to the top drive side bearing box 712B supporting the radial bearing 790B on the drive side.

[0103] Force in the axial direction acting on the top work roll 710 further acts on the radial bearing 790A on the work side, and the work side shift cylinders 715A and 715B finally support the force. Similarly, force in the axial direction acting on the top work roll 710 acts on the radial bearing 790B on the drive side, and the drive side shift cylinders 715C and 715D support the force.

[0104] Since the force in the axial direction acting on the top work roll 710 is sometimes in the work side direction and sometimes in the drive side direction, any of the cylinders of the work side shift cylinders 715A and 715B and the drive side shift cylinders 715C and 715D can support the force in both the work side direction and the drive side direction.

[0105] Each of the work-side entry-side shift cylinder 715A, the work-side exit-side shift cylinder 715B, the drive-side exit-side shift cylinder 715C, and the drive-side entry-side shift cylinder 715D is a double rod type cylinder in which internal pistons 923d and 925d (both of which on the exit side are exemplified) have two rods 923c and two rods 925c, respectively (both of which on the exit side are exemplified).

[0106] In addition, the present embodiment is also provided with a hydraulic circuit configured to send hydraulic oil to a plurality of hydraulic cylinders so that the drive side shift cylinders 715C and 715D and the work side shift cylinders 715A and 715B move in the axial direction and hold the position of the top work roll 710 in the axial direction.

[0107] The hydraulic circuit is configured such that in a case where the hydraulic circuit holds the position of the top work roll 710 in the axial direction and then only the hydraulic cylinders on one side between the drive side shift cylinders 715C, 715D and the work side shift cylinders 715A, 715B become a state of applying force to the top work roll 710 in the axial direction due to the external force received by the top work roll 710, the hydraulic cylinders on the other side between the drive side shift cylinders 715C, 715D and the work side shift cylinders 715A, 715B move in the direction opposite to the hydraulic cylinders on the one side.

[0108] In addition, pressure lines 805, 806, 807, and 808 for coupling the corresponding hydraulic oil chambers to each other on the entry side and the exit side are provided. For example, in the hydraulic circuit, a drive-side exit-side strip-side hydraulic oil chamber 923a and a drive-side entry-side strip-side hydraulic oil chamber 924a, and a work-side exit-side side-opposite-to-strip hydraulic oil chamber 925b and a work-side entry-side side-opposite-to-strip hydraulic oil chamber 926b are connected through the drive-side strip-side pressure line 807 and the work-side side-opposite-to-strip pressure line 808, and a drive-side exit-side side-opposite-to-strip hydraulic oil chamber 923b and a drive-side entry-side side-opposite-to-strip hydraulic oil chamber 924b, and a work-side exit-side strip-side hydraulic oil chamber 925a and a work-side entry-side strip-side hydraulic oil chamber 926a are connected through the drive-side side-opposite-to-strip pressure line 805 and the work-side strip-side pressure line 806, so that each of the drive side shift cylinders 715C and 715D and the work side shift cylinders 715A and 715B applies force to the top work roll 710 in the same direction.

[0109] Accordingly, when the direction of external force changes or when the distance between the supports on the supported side and the distance between the supports on the supporting side change due to thermal expansion of the mechanical device, the hydraulic circuit is configured such that when the hydraulic cylinders on one side between the drive side shift cylinders 715C, 715D and the work side shift cylinders 715A, 715B move by a predetermined stroke, the hydraulic cylinders on the other side between the drive side shift cylinders 715C, 715D and the work side shift cylinders 715A, 715B also move in the opposite direction by a predetermined stroke of the same magnitude without changing the amount of oil in the coupled pressure lines 805, 806, 807, and 808.

[0110] The radial bearing 790A is disposed in the top work side bearing box 712A. The radial bearing 790B is disposed in the top drive side bearing box 712B.

[0111] The force of the top work roll bending cylinders 740 and 741 and the top work roll bearing box backlash removing cylinder 760 acts on the radial bearings 790A and 790B. These radial bearings 790A and 790B support the force in the perpendicular direction acting on the roll axis while rotating.

[0112] Further, since the radial bearings 790A and 790B also support force in the axial direction acting on the top work side bearing box 712A and the top drive side bearing box 712B, 4-row tapered roller bearings are generally used. In addition, bearings of the same specifications are used for the radial bearing 790B on the drive side and the radial bearing 790A on the operation, and complicated maintenance work can be avoided.

[0113] In the driving systems of the work side shift cylinders 715A and 715B and the drive side shift cylinders 715C and 715D, the electromagnetic switching valve 810 for adjusting the inflow/outflow amount of oil is provided on the exit side of a pressure line 801 branched from a pressure line 800A through which pressure oil discharged from a pump (not illustrated) of the hydraulic device 90 flows and on the exit side of a tank line 802 branched from a tank line 800B connected to a tank (not illustrated) in which the pressure oil is stored.

[0114] When the electromagnetic switching valve 810 is a-energized, the rod sides (the work-side exit-side strip-side hydraulic oil chamber 925a side) of the work side shift cylinders 715A and 715B nearer the strip are connected to the pressure lines 801 and 800A via the work-side strip-side pressure line 806 and the pressure line 803, and force in the work side direction acts on the top work side bearing box 712A.

[0115] In addition, the rod sides (the drive-side exit-side side-opposite-to-strip hydraulic oil chamber 923B side) of the drive side shift cylinders 715C and 715D farther from the strip are also connected to the pressure lines 801 and 800A via the drive-side side-opposite-to-strip pressure line 805 and the pressure line 803, and force in the work side direction acts on the top drive side bearing box 712B.

[0116] Further, the rod sides (the work-side exit-side side-opposite-to-strip hydraulic oil chamber 925b side) of the work side shift cylinders 715A and 715B farther from the strip and the rod sides (the drive-side exit-side strip-side hydraulic oil chamber 923a side) of the drive side shift cylinders 715C and 715D nearer the strip are connected to the tank lines 802 and 800B via the work-side side-opposite-to-strip pressure line 808 or the drive-side strip-side pressure line 807 and the pressure line 804, respectively, so that the shift cylinders on both the work side and the drive side generate shift force in the work side direction.

[0117] When the electromagnetic switching valve 810 is b-energized, the rod sides (the work-side exit-side side-opposite-to-strip hydraulic oil chamber 925b side) of the work side shift cylinders 715A and 715B farther from the strip are connected to the pressure lines 801 and 800A via the work-side side-opposite-to-strip pressure line 808 and the pressure line 804, and force in the drive side direction acts on the top work side bearing box 712A.

[0118] In addition, the rod sides (the drive-side exit-side strip-side hydraulic oil chamber 923a side) of the drive side shift cylinders 715C and 715D nearer the strip are connected to the pressure lines 801 and 800A via the drive-side strip-side pressure line 807 and the pressure line 804, and force in the drive side direction acts on the top drive side bearing box 712B.

[0119] Further, the rod sides (the work-side exit-side strip-side hydraulic oil chamber 925a side) of the work side shift cylinders 715A and 715B nearer the strip and the rod sides (the drive-side exit-side side-opposite-to-strip hydraulic oil chamber 923b side) of the drive side shift cylinders 715C and 715D farther from the strip are connected to the tank lines 802 and 800B via the work-side strip-side pressure line 806 or the drive-side side-opposite-to-strip pressure line 805 and the pressure line 803, respectively, so that the shift cylinders on both the work side and the drive side generate shift force in the drive side direction.

[0120] When the electromagnetic switching valve 810 is made neutral, the pilot check valves 821 and 822 prevent the hydraulic oil from flowing to the rod sides nearer the strip and farther from the strip in all the work side shift cylinders 715A and 715B and the drive side shift cylinders 715C and 715D.

[0121] By the configuration of the electromagnetic switching valve 810 and the excitation control by the controller 80, the work side shift cylinders 715A and 715B and the drive side shift cylinders 715C and 715D support the top work roll 710 so as not to move in the axial direction when the shift of the top work roll 710 in the axial direction is stopped.

[0122] The pilot check valve 822 is provided on the pressure line 804 on the downstream side of the electromagnetic switching valve 810, and the pilot check valve 821 is provided on the pressure line 803 on the downstream side of the electromagnetic switching valve 810, and when the electromagnetic switching valve 810 becomes neutral, the pressure oil is prevented from flowing to both the rod sides and the head sides of the work side shift cylinders 715A and 715B and the drive side shift cylinders 715C and 715D. Thus, even when the shift of the top work roll 710 is stopped, the work side shift cylinders 715A and 715B and the drive side shift cylinders 715C and 715D support the top work roll 710 so as not to move in the axial direction.

[0123] Further, in consideration of an emergency such as when unexpected excessive thrust resistance force acts, the relief valves 811 and 812 are provided between the pilot check valves 821, 822 and the work side shift cylinders 715A, 715B and the drive side shift cylinders 715C, 715D, and the pressure rise in pipes is limited to the allowable pressure of the machine.

[0124] It should be noted that the hydraulic system of FIG. 7 depicts only a part for explaining the present invention, and a flow rate adjustment valve, a check valve, and the like are appropriately added as necessary.

[0125] FIG. 8 depicts a structure around the shift cylinder of the entry side on the work side and the drive side. For the purpose of explaining the operation, FIG. 8 is a diagram for explaining only a case where the pipes on the rod side nearer the strip on the work side and the pipes on the rod side farther from the strip on the drive side are connected to each other, but the same applies to other pipe coupling portions.

[0126] In FIG. 8, the center position of the distance between the support positions on the work side and the drive side is indicated by a line M, F.sub.sde is force by which the drive-side entry-side shift cylinder 715D supports the top drive side bearing box 712B, F.sub.swe is force by which the work-side entry-side shift cylinder 715A supports the top work side bearing box 712A, L.sub.a is a distance between the support positions on the work side and the drive side, and F.sub.tr is thrust force acting on the top work roll 710. Here, a case where thrust force in the work side direction is acting is assumed.

[0127] In the state depicted in FIG. 8, each of F.sub.swe and F.sub.sde is F.sub.tr/4, and although not illustrated, the force Fswd by which the work-side exit-side shift cylinder 715B on the exit side supports the top work side bearing box 712A and the force F.sub.sdd by which the drive-side exit-side shift cylinder 715C supports the top drive side bearing box 712B are also F.sub.tr/4, and the sum of these four is F.sub.tr to support the thrust force F.sub.tr.

[0128] FIG. 9 assumes a state where in FIG. 8, a distance La between the support positions on the work side and the drive side is extended by La due to heating up of the top work roll 710 by the rolled metal strip 5 or heat generation by the radial bearings 790A and 790B when rotating while receiving a load during rolling, the ambient temperature changes, or the like.

[0129] As depicted in FIG. 9, when the distance La between the support positions on the work side and the drive side changes by La, the support position on the drive side moves farther from the strip by La/2, the hydraulic oil flows from the sides farther from the strip of the drive side shift cylinders 715C and 715D toward the sides nearer the strip of the work side shift cylinders 715A and 715B, and the support position on the work side moves farther from the strip by La/2.

[0130] That is, in the hydraulic circuit of the present embodiment, even if the distance La between the support positions the work side and the drive side changes by La, the amount of oil in the pressure lines 805, 806, 807, and 808 on the exit side of the pilot check valves 821 and 822 does not change, so that the force supporting the top work roll 710 by the work side shift cylinders 715A and 715B and the force supporting the top work roll 710 by the drive side shift cylinders 715C and 715D can be maintained the same state, and thus the balance of the total support force does not change.

[0131] Therefore, the line M, which is the center position of the distance between the support positions on the work side and the drive side, remains the center position of the distance between the support positions on the work side and the drive side even if La changes by La. That is, since the line M is close to the center position of the rolled metal strip 5, even if thermal expansion occurs, slipping of the top work roll 710 and the rolled metal strip 5 in the axial direction only slightly occurs, and the rolling is not hindered.

[0132] Although a case where thermal expansion occurs is explained here, the support force does not similarly change even in a case where thermal contraction occurs, and the position of the line M does not change.

[0133] Next, a modified example of the present embodiment will be described using FIG. 10. FIG. 10 is a plan view for explaining the details of the top work roll part in the rolling mill of the modified example of the first embodiment.

[0134] FIG. 10 depicts an example of a configuration in which a shift block 712A1 including therein top work roll bending cylinders 740 and 741 is coupled to work side shift cylinders 715A and 715B on the work side, and a shift block 712B1 including therein the top work roll bending cylinders 740 and 741 is coupled to drive side shift cylinders 715C and 715D on the drive side.

[0135] Even in a case where such shift blocks 712A1 and 712B1 are used, the thrust reaction force can be made the same on the work side and the drive side, as similar to the case of the configurations depicted in FIG. 7 and the like in which the entry side fixing member 702 and the exit side fixing member 703 include therein the bending cylinders 740 and 741, respectively.

[0136] It should be noted that by adopting the configuration of FIG. 7 and providing a pressure measuring device on the secondary side of the pilot check valves 821 and 822, the thrust force acting on the roll can be accurately measured.

[0137] Next, effects of the present embodiment will be described.

[0138] According to the rolling mill of the first embodiment of the present invention described above, after the hydraulic circuit holds the position of the top work roll 710 in the axial direction, in a case where only the hydraulic cylinders on one side between the drive side shift cylinders 715C, 715D and the work side shift cylinders 715A, 715B become a state of applying force to the top work roll 710 in the axial direction due to the external force received by the top work roll 710, the hydraulic cylinders on the other side between the drive side shift cylinders 715C, 715D and the work side shift cylinder 715A, 715B move in the direction opposite to the hydraulic cylinders on the one side.

[0139] When the direction of the external force in the axial direction acting on the mill roll changes after the position of the mill roll in the axial direction is held, even if the backlash of one of the work side hydraulic cylinder and the drive side hydraulic cylinder is eliminated first, an operation in which the other hydraulic cylinder moves in the direction opposite to the one hydraulic cylinder by the same amount when the one hydraulic cylinder is pushed, cannot support, and moves is continuously repeated, and the remaining backlash is eliminated later and the other hydraulic cylinder also supports, so that it is possible to avoid that large external force in the axial direction continues to act on the one hydraulic cylinder until the backlash of the other hydraulic cylinder is eliminated.

[0140] That is, even if thermal expansion occurs, the direction of the thrust resistance force changes, or a gap exists in the axial direction of the roll between a bearing box and a bearing, inside a bearing, between a bearing and a roll, between a bearing box and a shift device, or the like, the thrust reaction force of the cylinders themselves of the work side shift cylinders 715A and 715B and the drive side shift cylinders 715C and 715D can be made the same as long as excessive thrust resistance force does not act, and it is possible to avoid the pressure in the hydraulic cylinders from rising to the set pressure of the relief valves 811 and 812 or higher. Therefore, an excessive load does not act on the support parts such as the bearings on the work side and the bearings on the drive side of the mill roll, and the lifetime can be improved. For example, if the lifetime of the bearing is Lh and the load is Pl, a relation of Lh(1/Pl).sup.10/3 is satisfied in the case of a roller bearing, and thus if 1/2 is substituted for Pl, Lh=10 is satisfied, so that the lifetime of the bearing can be extended 10 times as compared with a case where the thrust force is held on one side.

[0141] In addition, in a conventional configuration, when the pressure is raised to the relief valve set pressure or higher, since the hydraulic oil flows out from the secondary side of the pilot check valves to cause a deviation of the shift position, it is necessary to frequently adjust the shift position. In the configuration of the present embodiment, however, it is possible to suppress the pressure rise to the set pressure of the relief valves 811 and 812 or higher, so that an effect that it is not necessary to frequently adjust the shift position can be also obtained.

[0142] That is, the conventional complicated pressure measuring device and the adjustment of the inflow/outflow oil amount adjustment part are not required, and the device configuration can be simplified. In addition to the above, since it can be realized only by ON/OFF control of the electromagnetic switching valve 810 without a complicated controller, the device configuration of the control system can be simplified.

[0143] For example, in the case of Patent Document 1 described above, the support state of the thrust force may be changed before and after the operation of the relief valve such that the thrust force is supported on one side or the thrust force is supported on both sides. In addition, the operating pressure of the relief valve affects the pressure on the secondary side of the pilot check valve, but since the operating pressure of the relief valve changes depending on the flow rate, it may be difficult to determine, from the pressure measurement result on the secondary side of the pilot check valve, whether the thrust force is supported on one side or the thrust force is supported on both sides. Therefore, even if a pressure measuring device is installed on the secondary side of the pilot check valve and the pressure is measured, the thrust force is obtained by multiplying the areas of both pressure chambers of the cylinder, and thus it has been found that there may be a risk of difficulty in accurately obtaining the thrust force in a state where whether the cylinder supporting the thrust force is on one side or on both sides is uncertain.

[0144] However, in the configuration of the present embodiment, since the thrust force can be always supported on both sides including a case where abnormal thrust force acts and the relief valves 811 and 812 are operated, the thrust force can be accurately obtained from the pressure measurement result on the secondary side of the pilot check valves 821 and 822.

[0145] In addition, a rolling mill in which top and bottom rolls are inclined in directions opposite to each other in a cross state has a high strip-crown strip-shape control ability, but since large thrust force acts between the rolled metal strip 5 and the top work roll 710, the load capacity is limited depending on the strength of the bearing and the end of the roll that receive the thrust force.

[0146] In a case where the load conditions are particularly severe, grease cannot be applied to lubricate the bearing and it becomes necessary to adopt oil lubrication such as circulation lubrication. Where oil lubrication such as circulation lubrication is adopted, the facility becomes complicated and the facility cost becomes high.

[0147] In contrast, by adopting the configuration of the present embodiment described above, if the acting load can be reduced by half, there is a merit that simple grease lubrication can be adopted as a machine facility, and the facility cost and operation cost can be suppressed to be low. In addition, if the acting load can be reduced by half, the diameter of the top work roll 710 can be made small, which leads to a reduction in the rolling load, and thus it can be applied to rolling of hard materials.

[0148] In the above description, a case where the bearings receive both the bending force and the thrust force is described, but there is also a case where a radial bearing for receiving the bending force and a thrust bearing for receiving the thrust force are separately provided. The structure of the bearings is appropriately selected, and by adopting the structure of the present embodiment in these structures, the acting load can be reduced by half, leading to the lifetime extension of the roll support parts such as the bearings.

[0149] Further, the resistance in the up-down direction of the thrust receiving parts affects a rolling load measurement value. In a case where a thrust force support device is provided only on one side, it may cause a differential load. Since the thrust force can be made the same on the work side and the drive side by adopting the configuration of the present embodiment, the differential load can be minimized depending on friction coefficients of the thrust receiving parts.

[0150] Therefore, by adopting the configuration of the present embodiment, it is possible to obtain a structure in which the movement resistance of the thrust receiving part in the rolling direction is reduced. This makes it possible to reduce the resistance when changing the inclination of the roll during rolling.

[0151] In addition, the hydraulic circuit can be configured such that the drive-side exit-side strip-side hydraulic oil chamber 923a and the work-side exit-side side-opposite-to-strip hydraulic oil chamber 925b are connected to each other through the pressure lines 807 and 808, and the drive-side exit-side side-opposite-to-strip hydraulic oil chamber 923b and the work-side exit-side strip-side hydraulic oil chamber 925a are connected to each other through the pressure lines 805 and 806 so that each of the drive side shift cylinders 715C and 715D and the work side shift cylinders 715A and 715B applies force to the top work roll 710 in the same direction, and thus the amount of hydraulic oil moving in the pipes does not change.

[0152] Further, the hydraulic circuit is configured such that when the hydraulic cylinders on one side between the drive side shift cylinders 715C, 715D and the work side shift cylinders 715A, 715B move by a predetermined stroke, the hydraulic cylinders on the other side between the drive side shift cylinders 715C, 715D and the work side shift cylinders 715A, 715B also move in the opposite direction by the predetermined stroke without changing the amount of oil in the coupled pressure lines 805, 806, 807, and 808, so that the shift cylinders can be moved so as to equalize both the strokes on the drive side and the work side, the pressure in the pipes does not become high enough to exceed the set pressure of the relief valves 811 and 812, and the thrust force can be supported by applying force to the mill roll in the same direction on both the drive side and the work side.

[0153] In addition, the drive side shift cylinders 715C and 715D and the work side shift cylinders 715A and 715B are double rod cylinders, the drive-side exit-side strip-side hydraulic oil chamber 923a and the drive-side exit-side side-opposite-to-strip hydraulic oil chamber 923b have the same cross-sectional area in the direction in which the fore of the hydraulic oil is applied, the work-side exit-side strip-side hydraulic oil chamber 925a and the work-side exit-side side-opposite-to-strip hydraulic oil chamber 925b have the same cross-sectional area in the direction in which the force of the hydraulic oil is applied, the drive-side exit-side strip-side hydraulic oil chamber 923a and the work-side exit-side side-opposite-to-strip hydraulic oil chamber 925b are connected to each other through the pressure lines 807 and 808, and the drive-side exit-side side-opposite-to-strip hydraulic oil chamber 923b and the work-side exit-side strip-side hydraulic oil chamber 925a are connected to each other through the pressure lines 805 and 806, so that it is possible to obtain effects that the force for supporting the thrust force acting on the mill roll in the work side direction and the force for supporting the thrust force in the drive side direction can be made equal, and in a case where the bearings on the work side and the drive side of the mill roll have the same specifications, the lifetime of the support parts such as the bearings can be maximized, and the damage of each part due to a load can be reduced. In addition, by using the double rods, the bearing box coupling parts of the hydraulic cylinder on the drive side and the hydraulic cylinder on the work side can be made nearer the strip, so that the structures around the bearing box coupling parts can be symmetrical between the drive side and the work side, and the structures can be made common, and the device can be made simpler as compared with other embodiments to be described later.

[0154] Further, the drive side shift cylinders 715C and 715D and the work side shift cylinders 715A and 715B are provided on each of the entry side and the exit side, and the pressure lines 805, 806, 807, and 808 for coupling the corresponding hydraulic oil chambers on the entry side and the exit side are provided, and thus the support force can be made the same on the entry side and the exit side of the hydraulic cylinders. Accordingly, a moment cannot act on the bearing box, so that the rotation of the mill roll in the horizontal plane can be prevented, and the support force can be equalized on the entry side and the exit side of the rolled metal strip 5 with a simple structure.

[0155] In addition, the controller 80 for controlling the driving of a plurality of hydraulic cylinders is provided, and the controller 80 is configured to be capable of shifting the top work roll 710 in the axial direction by causing the drive side shift cylinders 715C and 715D and the work side shift cylinders 715A and 715B to be driven, so that it is possible to automatically perform shifting of the mill roll in the axial direction.

[0156] Further, the horizontal direction actuator for adjusting the angle of each roll in the horizontal direction is provided. Although the thrust force acting on the mill roll increases when the mill roll is set at an optional inclination angle relative to the strip, the large thrust force is supported by half on the work side and half on the drive side, the support force is equalized on the entry side and the exit side with a simple structure, a moment cannot act on the bearing box, and the support force per hydraulic cylinder can be reduced to .

[0157] It should be noted that it is also possible to change the diameters of the two rods in one double rod hydraulic cylinder, that is, to make the cross-sectional areas of the two hydraulic oil chambers different.

[0158] In this case, the cross-sectional areas of the hydraulic oil chambers nearer the strip on the drive side and farther from the strip on the work side are made equal to each other and the chambers are coupled to each other through a pipe, and the cross-sectional areas of the hydraulic oil chambers farther from the strip on the drive side and nearer the strip on the work side are made equal to each other and the chambers are coupled to each other through a pipe, so that the thrust reaction force can be reduced by half by applying the same force as the thrust reaction force by the side farther from the strip on the drive side and the side nearer the strip on the work side and the side nearer the strip on the drive side and the side farther from the strip on the work side. Thus, the support force can be made the same on the drive side and the work side, and the lifetime of the roll support parts such as the bearings can be maximized.

[0159] In addition, in a case where the force for supporting the thrust force in the work side direction is selectively increased, it is possible to select to provide a diameter difference in the rod diameter so that the cross-sectional areas of the hydraulic oil chambers farther from the strip on the work side and nearer the strip on the drive side are larger than the cross-sectional areas of the hydraulic oil chambers nearer the strip on the work side and farther from the strip on the drive side.

Second Embodiment

[0160] A rolling mill and a rolling method of a second embodiment of the present invention will be described using FIG. 11. FIG. 11 is a plan view for explaining the details of a top work roll part in the rolling mill of the second embodiment.

[0161] In the rolling mill of the present embodiment depicted in FIG. 11, each of a drive-side exit-side shift cylinder 715C1, a drive-side entry-side shift cylinder 715D1, a work-side entry-side shift cylinder 715A1, and a work-side exit-side shift cylinder 715B1 is a single rod cylinder, and single rods 923c and 925c1 (both of which on the exit side are exemplified) of all the cylinders are of the same orientation in the work side direction.

[0162] Therefore, the work-side entry-side shift cylinder 715A1 is connected to a work side arm 714A and a top work side bearing box 712A via a transmission member 715A2, and the work-side exit-side shift cylinder 715B1 is connected to a work side arm 714B and the top work side bearing box 712A via a transmission member 715B2, so that the top work roll 710 is supported.

[0163] Further, a drive-side exit-side strip-side hydraulic oil chamber 923a1 and a work-side exit-side side-opposite-to-strip hydraulic oil chamber 925b1 are connected to each other through drive-side strip-side pressure lines 807A and 807B, the cross-sectional areas in the direction in which the force of the hydraulic oil is applied (areas of a piston 923d1 and a piston 925d1) are the same, a drive-side exit-side side-opposite-to-strip hydraulic oil chamber 923b1 and a work-side exit-side strip-side hydraulic oil chamber 925a1 are connected to each other through pressure lines 805A and 805B and a work-side strip-side pressure line 806, and the cross-sectional areas in the direction in which the force of the hydraulic oil is applied (areas of the piston 923d1 and the piston 925d1) are the same.

[0164] Even with such a configuration, as similar to the configuration of FIG. 7 described in the first embodiment, even in a case where a thermal deformation of La occurs, it is possible to support with equal force on the drive side and the work side by moving to opposite sides across a line M by La/2 on the drive side and the work side.

[0165] That is, after the roll set 710A is moved in the drive side direction while receiving the thrust resistance force in the work side direction from the roll set 710A and the position of the roll set 710A is set, when the thrust resistance force in the drive side direction acts on the roll set 710A due to a change in conditions such as the rotation of the roll of the rolling mill to move only the roll set 710A in the drive side direction, the thrust resistance force can be equally supported on both the drive side and the work side, so that the pressure does not rise to the set pressure of the relief valves 811 and 812 or higher.

[0166] It should be noted that even in this case, the relief valves 811 and 812 may be provided on the secondary side of the pilot check valves 821 and 822 in consideration of an emergency such as when unexpected excessive thrust resistance force acts.

[0167] The other configurations and operations are substantially the same as those of the rolling mill and the rolling method of the first embodiment described above, and the details thereof are omitted.

[0168] Even in the rolling mill and the rolling method of the second embodiment of the present invention, effects substantially similar to those of the rolling mill and the rolling method of the first embodiment described above can be obtained.

[0169] In addition, in the present embodiment, the same hydraulic cylinders can be used on the work side and the drive side, but mechanical devices such as shift devices around the cylinders have different structures between the work side and the drive side. Therefore, although the facility becomes complicated, the amount of projection of the shift devices including the shift cylinders from the housing on the work side can be made smaller as compared with the configuration of the first embodiment, and thus the configuration can be suitably adopted when it is difficult to make the shift devices larger due to arrangement or the like of a rearrangement device on the work side.

[0170] Specifically, since the roll rearrangement device on the work side can be disposed close to the rolling mill side and the facility can be configured similar to a case where the shift cylinder is provided only on the work side of a normal work roll shift, the space on the work side does not need to be enlarged, and thus an economical space can be realized.

[0171] In addition, in a case where there is a space restriction on the drive side depending on the device, the head sides of the work side shift cylinders 715A1 and 715B1 can be made farther from the strip, and the head sides of the drive side shift cylinders 715C1 and 715D1 can be made nearer the strip.

[0172] The configuration of the present embodiment is preferable when the space on the work side is secured regardless of hot rolling or cold rolling.

[0173] It should be noted that the configuration of the single rod cylinder of the present embodiment is not limited to the configuration depicted in FIG. 11, and the drive-side exit-side shift cylinder 715C1 and the drive-side entry-side shift cylinder 715D1 can be also configured such that the single rods face outward in the axial direction by supporting the drive side arms 714C and 714D via the transmission members as similar to the work-side entry-side shift cylinder 715A1 and the work-side exit-side shift cylinder 715B1. In this case, an intermediate cylinder is further provided as depicted in FIG. 14 to be described later.

[0174] If the shift cylinders are disposed so that the rods face outward in this manner, the rolling mill becomes compact. A space for rearranging the rolls can be secured on the work side, and a space becomes compact similarly even on the drive side, so that a space can be secured. Further, since the structure on the drive side can be symmetrical with the structure on the work side, the structure can be made common, and the device configuration can be simplified.

Third Embodiment

[0175] A rolling mill and a rolling method of a third embodiment of the present invention will be described using FIG. 12 and FIG. 13. FIG. 12 and FIG. 13 are plan views for explaining the details of a top work roll part in the rolling mill of the third embodiment.

[0176] In the rolling mill of the present embodiment depicted in FIG. 12 and FIG. 13, a pressure line 805B1 branched from the pressure line 803 is connected to a drive-side entry-side side-opposite-to-strip hydraulic oil chamber 833b of a double rod drive-side entry-side shift cylinder 833, and a pressure line 805B2 branched from the pressure line 803 is connected to a work-side entry-side strip-side hydraulic oil chamber 830a of a double rod work-side entry-side shift cylinder 830.

[0177] Further, a drive-side entry-side side-opposite-to-strip hydraulic oil chamber 833b and a drive-side exit-side side-opposite-to-strip hydraulic oil chamber 832b of a double rod drive-side exit-side shift cylinder 832 are connected to each other through a pressure line 823, the drive-side exit-side side-opposite-to-strip hydraulic oil chamber 832b and a work-side exit-side strip-side hydraulic oil chamber 831a of a double rod work-side exit-side shift cylinder 831 are connected to each other through a pressure line 824, and the work-side exit-side strip-side hydraulic oil chamber 831a and the work-side entry-side strip-side hydraulic oil chamber 830a are connected to each other through a pressure line 825.

[0178] It should be noted that for the purpose of explaining the operation, only a case where the pipes on the rod sides nearer the strip on the work side and the rod sides farther from the strip on the drive side are connected to each other is described, but the rod sides (the work-side entry-side side-opposite-to-strip hydraulic oil chamber 830b and the work-side exit-side side-opposite-to-strip hydraulic oil chamber 831b) farther from the strip on the work side and the rod sides (the drive-side entry-side strip-side hydraulic oil chamber 833a and the drive-side exit-side strip-side hydraulic oil chamber 832a) nearer the strip on the drive side are similarly connected to each other through the pipes.

[0179] A case where the thrust force in the work side direction is acting is assumed even in FIG. 12 and FIG. 13 as similar to FIG. 8.

[0180] FIG. 13 depicts a state in which the top work roll 710 has an optional inclination angle relative to the rolled metal strip 5 in FIG. 12. The center of a strip width at a strip passing position is substantially the same as the center of the rolling mill, and an inclination angle 0c is provided counterclockwise about the center position of the rolling mill in the strip width direction.

[0181] In FIG. 13, in a case where the distances from the center position of the rolling mill to thrust force action positions are the same on the work side and the drive side when the inclination angle ec is provided in a state where the pilot check valves 821 and 822 are active during rolling, the support position on the entry side on the work side moves nearer the strip by ALwe, and the support position on the exit side on the work side moves farther from the strip by ALwd. Further, the support position on the entry side on the drive side moves farther from the strip by ALde, and the support position on the exit side on the drive side moves nearer the strip by ALdd.

[0182] The hydraulic oil moves in the pressure lines 805B1, 805B2, 823, 824, and 825 by these movements, but the total amount of hydraulic oil on the exit side (secondary side) of the pilot check valves 821 and 822 does not change.

[0183] Since the rod sides farther from the strip on the work side and the rod sides nearer the strip on the drive side are similarly connected through the pressure line, the total amount of hydraulic oil on the exit side (secondary side) of the pilot check valves 821 and 822 does not similarly change.

[0184] On the other hand, there may be a case where the top work roll 710 shifts to various positions or a case where the distances from the center of the rolling mill to the thrust force action positions differ between the work side and the drive side even when the top work roll 710 does not shift.

[0185] In this case, with the inclination of the top work roll 710, a slight change occurs in the distances between the support positions on the work side and the drive side.

[0186] In response to this change, a flow of hydraulic oil occurs between the work side and the drive side as similar to when the distances between the support positions on the work side and the drive side change due to thermal expansion of the top work roll 710 or the like. However, each value of L.sub.we, L.sub.wd, L.sub.de, and L.sub.dd slightly deviates from the action position of the thrust force obtained geometrically with the inclination of the top work roll 710, but there is no significant change.

[0187] Thus, in the mill for shifting the work rolls, when the top work roll 710 is inclined during rolling, it is possible to incline the work roll without greatly changing the shift position and without exerting such an excessive load that raises the pressure to the set pressure of the relief valves 811 and 812 or higher during the inclination process.

[0188] Further, since only a slight deviation is caused about the line M as a center at the time of inclination, the top work roll 710 can be inclined in a state where almost no slipping between the rolled metal strip 5 and the top work roll 710 occurs.

[0189] After the shift position of the top work roll 710 is determined, or after the position of the top work roll 710 in the axial direction is to be determined using the configuration of the present embodiment even in a mill with no shift, excessive force does not act on the shift device even if the inclination angle is changed during rolling and even if the pilot check valves 821 and 822 remain active.

[0190] The value of the deviation in the roll axis direction due to a change in the inclination angle is very small because the deviation between the center of the distance between the support positions and the center of the inclination (the center position of the rolling mill) is small. When such a small deviation occurs, the total amount of hydraulic oil on the secondary side of the pilot check valves 821 and 822 does not change.

[0191] It should be noted that even in another embodiment as depicted in FIG. 11, if the total amount of hydraulic oil on the secondary side of the pilot check valves 821 and 822 does not change even when the roll is inclined relative to the rolled metal strip 5 during rolling, the support force can be equalized on the work side and the drive side of each cylinder.

[0192] The other configurations and operations are substantially the same as those of the rolling mill and the rolling method of the first embodiment described above, and the details thereof are omitted.

[0193] Even in the rolling mill and the rolling method of the third embodiment of the present invention, effects substantially similar to those of the rolling mill and the rolling method of the first embodiment described above can be obtained.

Fourth Embodiment

[0194] A rolling mill and a rolling method of a fourth embodiment of the present invention will be described using FIG. 14. FIG. 14 is a plan view for explaining the details of a top work roll part in the rolling mill of the fourth embodiment. It should be noted that although only the exit side is depicted in FIG. 14, the entry side has a similar structure, and the details thereof are omitted.

[0195] In the rolling mill of the present embodiment depicted in FIG. 14, a drive-side exit-side shift cylinder 935C and a work-side exit-side shift cylinder 935B are single rod cylinders. A rod 943c of the drive-side exit-side shift cylinder 935C and a rod 945c of the work-side exit-side shift cylinder 935B are oriented in opposite directions, and are oriented in opposite directions to the rolled metal strip 5 side.

[0196] Further, a single rod first intermediate cylinder 971 and a single rod second intermediate cylinder 973 are provided. These first intermediate cylinder 971 and second intermediate cylinder 973 are dummy cylinders and no pressing targets particularly exist.

[0197] Further, a drive-side exit-side rod-side hydraulic oil chamber 943a of the drive-side exit-side shift cylinder 935C and a rod side hydraulic oil chamber 971b of the first intermediate cylinder 971 are connected to each other through an intermediate rod pressure line 807C2, and a drive-side exit-side head-side hydraulic oil chamber 943b and a head side hydraulic oil chamber 973a of the second intermediate cylinder 973 are connected to each other through an intermediate rod pressure line 805C2.

[0198] Further, a work-side exit-side rod-side hydraulic oil chamber 945a of the work-side exit-side shift cylinder 935B and a rod side hydraulic oil chamber 973b of the second intermediate cylinder 973 are connected to each other through an intermediate rod pressure line 805C1, and a work-side exit-side rod-side hydraulic oil chamber 945b and a head side hydraulic oil chamber 971a of the first intermediate cylinder 971 are connected to each other through an intermediate rod pressure line 807C1.

[0199] In addition, the ratio of the cross-sectional area of the drive-side exit-side rod-side hydraulic oil chamber 943a to the cross-sectional area of the drive-side exit-side head-side hydraulic oil chamber 943b in the direction in which the force of the hydraulic oil is applied, the ratio of the cross-sectional area of the work-side exit-side rod-side hydraulic oil chamber 945a to the cross-sectional area of the work-side exit-side head-side hydraulic oil chamber 945b in the direction in which the force of the hydraulic oil is applied, the ratio of the cross-sectional area of the rod side hydraulic oil chamber 971b to the cross-sectional area of the head side hydraulic oil chamber 971a in the direction in which the force of the hydraulic oil is applied, and the ratio of the cross-sectional area of the rod side hydraulic oil chamber 973b to the cross-sectional area of the head side hydraulic oil chamber 973a in the direction in which the force of the hydraulic oil is applied are the same in all the cylinders.

[0200] Even in this case, when the drive side arm 714C moves toward the drive side by half the remaining backlash, the work side arm 714B moves toward the work side by half the remaining backlash, and the amount of hydraulic oil on the secondary side of the pilot check valves 821 and 822 does not change.

[0201] In addition, since the cross-sectional area in contact with the hydraulic oil in the work side shift cylinder 935B and the drive side shift cylinder 935C has a relation of A.sub.wr<A.sub.dh and the pressure has a relation of p.sub.wr>p.sub.dh, a relation of A.sub.wrp.sub.wr=d.sub.hp.sub.dh is satisfied, and thus the support force of the drive side arm 714C and the support force of the work side arm 714B are the same.

[0202] Similarly, in a case where the thrust force in the work side direction acts on the roll set 710A, the thrust reaction force of the same force is generated on the rod side of the drive side and the head side of the work side, so that the support force of the thrust force on the work side and the support force of the thrust force on the drive side can be reduced to half even in the configuration of the present embodiment.

[0203] The other configurations and operations are substantially the same as those of the rolling mill and the rolling method of the first embodiment described above, and the details thereof are omitted.

[0204] Even in the rolling mill and the rolling method of the fourth embodiment of the present invention, effects substantially similar to those of the rolling mill and the rolling method of the first embodiment described above can be obtained.

[0205] In addition, in the configuration of the fourth embodiment, the bearing box coupling part of the hydraulic cylinder on the drive side and the bearing box coupling part of the hydraulic cylinder on the work side can be close to the rolled metal strip 5, so that the structures around the bearing box coupling parts can be symmetrical between the drive side and the work side. Accordingly, the structures can be made common, and thus the device can be simplified.

[0206] In addition, since the length of the hydraulic cylinder becomes shorter than that of the double rod configuration as in the first embodiment, the protrusion on the work side of the shift device can be reduced, and thus the space of the roll rearrangement device can be secured.

[0207] It should be noted that a piston 973d of the second intermediate cylinder 973, a piston 943d of the drive-side exit-side shift cylinder 935C, a piston 945d of the work-side exit-side shift cylinder 935B, and a piston 971d of the first intermediate cylinder 971 can have the same cross-sectional area, but it is not necessary to be the same, and it is only necessary that the ratios of the cross-sectional areas of the pistons of the respective cylinders on the head/rod sides are the same.

Others

[0208] It should be noted that the present invention is not limited to the above-described embodiments, but includes various modified examples. The above embodiments have been described in detail for the purpose of clearly explaining the present invention, and are not necessarily limited to those having all the described configurations.

[0209] In addition, it is also possible to replace a part of a configuration of an embodiment with a configuration of another embodiment, and to add a configuration of an embodiment to a configuration of another embodiment. In addition, it is also possible to add, delete, or replace a part of a configuration of each embodiment to/from/with another configuration.

[0210] For example, the rolling mill in which the mill roll is shifted in the roll axial direction has been described as an example, but the present invention also covers, for example, a rolling mill provided with a hydraulic cylinder for fixing the position in the axial direction, that is, a rolling mill in which the mill roll is not shifted in the axial direction.

DESCRIPTION OF REFERENCE CHARACTERS

[0211] 1: rolling facility [0212] 5: rolled metal strip [0213] 30: first rolling mill stand (rolling mill) [0214] 40: second rolling mill stand (rolling mill) [0215] 50: third rolling mill stand (rolling mill) [0216] 60: fourth rolling mill stand (rolling mill) [0217] 70: fifth rolling mill stand (rolling mill) [0218] 80: controller [0219] 90: hydraulic device [0220] 700: housing [0221] 702: entry side fixing member [0222] 703: exit side fixing member [0223] 705A, 705B, 705E, 705F, 706C, 706D: hydraulic cylinder (horizontal direction actuator) [0224] 710: top work roll (mill roll) [0225] 710A: roll set [0226] 711: bottom work roll (mill roll) [0227] 712: top work roll bearing box [0228] 712A: top work side bearing box [0229] 712A1: shift block [0230] 712B: top drive side bearing box [0231] 712B1: shift block [0232] 713: bottom work roll bearing box [0233] 713A, 713B: bearing box [0234] 714A, 714B: work side arm [0235] 714C, 714D: drive side arm [0236] 715: shift cylinder (hydraulic cylinder) [0237] 715A, 715A1, 830: work-side entry-side shift cylinder (hydraulic cylinder, work side hydraulic cylinder) [0238] 715a2, 715b2: Transmission Member [0239] 715B, 715B1, 831, 935B: work-side exit-side shift cylinder (hydraulic cylinder, work side hydraulic cylinder) [0240] 715C, 715C1, 832, 935C: drive-side exit-side shift cylinder (hydraulic cylinder, drive side hydraulic cylinder) [0241] 715D, 715D1, 833: drive-side entry-side shift cylinder (hydraulic cylinder, drive side hydraulic cylinder) [0242] 716: position sensor [0243] 717: shift cylinder (hydraulic cylinder) [0244] 720: top intermediate roll (mill roll) [0245] 721: bottom intermediate roll (mill roll) [0246] 722: top intermediate roll bearing box [0247] 723: bottom intermediate roll bearing box [0248] 730: top back-up roll (mill roll) [0249] 731: bottom back-up roll (mill roll) [0250] 732: top back-up roll bearing box [0251] 733: bottom back-up roll bearing box [0252] 740, 741, 742, 743: top work roll bending cylinder [0253] 744, 745, 746, 747: bottom work roll bending cylinder [0254] 750, 751: top intermediate roll bending cylinder [0255] 752, 753: bottom intermediate roll bending cylinder [0256] 760: top work roll bearing box backlash removing cylinder [0257] 762: bottom work roll bearing box backlash removing cylinder [0258] 771: top intermediate roll bearing box backlash removing cylinder [0259] 773: bottom intermediate roll bearing box backlash removing cylinder [0260] 780: top back-up roll bearing box backlash removing cylinder [0261] 782: bottom back-up roll bearing box backlash removing cylinder [0262] 790A, 790B: radial bearing [0263] 800A, 801: pressure line [0264] 800B, 802: tank line [0265] 803, 804: pressure line [0266] 805: drive-side side-opposite-to-strip pressure line (pipe) [0267] 805A, 805B, 805B1, 805B2, 823, 824, 825: pressure line (pipe) [0268] 805C1, 805C2: intermediate rod pressure line (pipe) [0269] 806: work-side strip-side pressure line (pipe) [0270] 805: drive-side strip-side pressure line (pipe) [0271] 807A, 807B: drive-side strip-side pressure line [0272] 807C1, 807C2: intermediate rod pressure line [0273] 808: work-side side-opposite-to-strip pressure line (pipe) [0274] 810: electromagnetic switching valve [0275] 811, 812: relief valve [0276] 821, 822: pilot check valve [0277] 830a: work-side entry-side strip-side hydraulic oil chamber [0278] 830b: work-side entry-side side-opposite-to-strip hydraulic oil chamber [0279] 831a: work-side exit-side strip-side hydraulic oil chamber [0280] 831b: work-side exit-side side-opposite-to-strip hydraulic oil chamber [0281] 833a: drive-side entry-side strip-side hydraulic oil chamber [0282] 833b: drive-side entry-side side-opposite-to-strip hydraulic oil chamber [0283] 832a, 923a, 923a1: drive-side exit-side strip-side hydraulic oil chamber (drive-side strip-side hydraulic oil chamber) [0284] 832b, 923b, 923b1: drive-side exit-side side-opposite-to-strip hydraulic oil chamber (drive-side side-opposite-to-strip hydraulic oil chamber) [0285] 923c, 925c: rod [0286] 923c1: single rod (drive side hydraulic cylinder rod) [0287] 923d, 923d1, 925d, 925d1, 943d, 945d, 971d, 973d: piston [0288] 924a: drive-side entry-side strip-side hydraulic oil chamber (drive-side strip-side hydraulic oil chamber) [0289] 924b: drive-side entry-side side-opposite-to-strip hydraulic oil chamber (drive-side side-opposite-to-strip hydraulic oil chamber) [0290] 925a, 925a1: work-side exit-side strip-side hydraulic oil chamber (work-side strip-side hydraulic oil chamber) [0291] 925b, 925b1: work-side exit-side side-opposite-to-strip hydraulic oil chamber (work-side side-opposite-to-strip hydraulic oil chamber) [0292] 925c1: single rod (work side hydraulic cylinder rod) [0293] 926a: work-side entry-side strip-side hydraulic oil chamber (work-side strip-side hydraulic oil chamber) [0294] 926b: work-side entry-side side-opposite-to-strip hydraulic oil chamber (work-side side-opposite-to-strip hydraulic oil chamber) [0295] 943a: drive-side exit-side rod-side hydraulic oil chamber (drive-side strip-side hydraulic oil chamber) [0296] 943b: drive-side exit-side head-side hydraulic oil chamber (drive-side side-opposite-to-strip hydraulic oil chamber) [0297] 943c: rod (drive side hydraulic cylinder rod) [0298] 945a: work-side exit-side rod-side hydraulic oil chamber (work-side strip-side hydraulic oil chamber) [0299] 945b: work-side exit-side head-side hydraulic oil chamber (work-side side-opposite-to-strip hydraulic oil chamber) [0300] 945c: rod (work side hydraulic cylinder rod) [0301] 971: first intermediate cylinder [0302] 971a: head side hydraulic oil chamber [0303] 971b: rod side hydraulic oil chamber [0304] 973: second intermediate cylinder [0305] 973a: head side hydraulic oil chamber [0306] 973b: rod side hydraulic oil chamber