JP2714071B2 - Rolling mill - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a cold rolling technology for a metal strip, and more particularly to a support for supporting a work roll suitable for high hardness and high quality material rolling from a rolling direction. The present invention relates to a multi-high rolling mill provided with a device.

[Conventional technology]

In recent years, work rolls tend to be reduced in diameter with the need for high-pressure rolling, high-hardness material rolling, and ultra-thin material rolling. In reducing the diameter of the work roll, Japanese Patent Application Laid-Open
A work roll support device as described in JP-A-60-64709 has been invented. This device, as shown in FIGS. 3 and 4,
The work roll is rolled and supported by a support roll 4 from a lateral direction, and the support roll is supported by a support frame 7 by a hydrostatic bearing over the entire range of the roll surface length. Further, the support roll is made of a highly wear-resistant material.

[Problems to be solved by the invention]

In the above prior art, since the support roll supporting the work roll is supported by the hydrostatic bearing, even if the surface of the support roll is slightly scratched by a foreign substance or the like, the important work roll surface is damaged. It is necessary to change the support roll frequently and prevent re-polishing so as not to cause this. However, there has been a problem that the hydrostatic bearing support must be replaced frequently and re-ground in accordance with the decrease in the diameter of the support roll. When the surface of the work roll is damaged, the surface quality of the material to be rolled is greatly reduced. Further, since the support roll is supported by the support frame over the entire range of the roll surface length by the hydrostatic bearing, there is a problem that the horizontal deflection of the work roll cannot be sufficiently suppressed. For example, FIG. 5 shows a work roll diameter of 40φ, a support roll diameter of 36φ, and a hydrostatic bearing pressure of 100 kg / cm ^2.
The effect of the hydrostatic bearing support length on the work roll deflection when the plate width is 400 mm and the load distribution force (tangential force, etc.) is 10 kg / mm is shown. (This figure was obtained by calculation.) In this figure, for example, the work roll surface length is 500 mm and the hydrostatic bearing support length is 500 mm
In the case of (1), the work roll is deflected by 60 μm, which is a large shape defect of about 1% at a steepness indicating the degree of shape defect of the material to be rolled according to an experiment. The steepness is
It is expressed as the ratio of the wave height of the plate to its pitch.

An object of the present invention is to suppress the surface damage of the work roll and reduce the frequency of replacing the hydrostatic bearing support.

[Means for Solving the Problems] The object is to provide a pair of upper and lower work rolls reinforced by reinforcing rolls from above and below, and a plurality of stages for rollingly supporting at least one of the work rolls from a lateral direction. In a rolling mill provided with support rolls, as the support roll, a first support roll having a cylindrical integral structure that directly rolls and supports the work roll, and a single roll or a plurality that further rolls and supports the first support roll. And a second supporting roll having a cylindrical integral structure, and a supporting frame for supporting each of the second supporting rolls with a hydrostatic bearing.

[Action]

First, since the second support roll is supported by hydrostatic bearings instead of the first support roll that directly supports the work roll, the first support roll is frequently changed so as not to damage the surface of the work roll, and reground. Even if it does not affect the second support roll, there is almost no need to replace or regrind the hydrostatic bearing support. Further, when the surface hardness of the first support roll is lower than that of the work roll and the second support roll, even if a foreign substance or the like is caught, the first support roll is absorbed by the first support roll, making it difficult for the work roll surface to be damaged. The frequency of re-polishing is also greatly reduced.

Next, the deflection of the work roll can be suppressed by changing the hydrostatic bearing support range of the second support roll according to the plate width. For example, in the example of FIG.
In the case of 500 mm and plate width of 400 mm, if the hydrostatic bearing support length is 430 mm, the work roll deflection is 0 μm, and if the hydrostatic bearing support length is 400 mm, which is the same as the plate width, the work roll deflection is 20 mm.
μm.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

In the rolling mill of the present embodiment, a pair of upper and lower work rolls 1 for rolling the material 10 to be rolled, an intermediate roll 2 in which the roll centers of the respective work rolls 1 are shifted by e in the rolling direction, A six-high rolling mill consisting of a reinforcing roll 3 in contact with the roll 2 and receiving a rolling load is applied.

Next, the configuration and operation of the work roll support device will be described. The work roll 1 is directly supported by a first support roll 4, and the first support roll 4 is further supported by a second support roll 5. The second support roll 5 includes a plurality of hydrostatic bearings 6 provided on a support frame 7.
And is supported by a hydrostatic bearing. Fluid is supplied to each hydrostatic bearing portion 6 from a pump or the like (not shown) through the hole 17, the chamber 18, and the hole 13. Here, the chamber 18 is partitioned by nuts 11 on both sides. The nut 11 is internally threaded and is movably secured to a similarly threaded shaft 12. The shaft 12 has a bearing 16 at one end and a support frame 7 via a bearing box 15.
, And can be rotated by a driving device (not shown). The support frame is fixed to a housing or the like (not shown). Further, both shaft ends of the first support roll 4 are supported by a hydrostatic bearing portion 9 by a hydrostatic bearing portion 9, and fluid is supplied to the hydrostatic bearing portion 9 through a hole 19. Similarly, both shaft ends of the second support roll 5 are supported by a hydrostatic bearing portion 8 by a hydrostatic bearing portion 8. Fluid is supplied to the hydrostatic bearing portion 8 through a hole 20.

The fluid supplied to each of the hydrostatic bearings 6, 8, 9 is a coolant for cooling the rolls or a liquid having no problem if mixed into the coolant.

The change of the hydrostatic bearing support range is performed as follows. In FIG. 2, since the chamber 18 is partitioned by the nuts 11 on both sides, fluid is supplied only to the holes 13 inside the nuts 11 on both sides, and accordingly, the static pressure at which the fluid is supplied is increased. The range of the bearing portion 6 becomes a hydrostatic bearing support range. When a wide material to be rolled is to be rolled, when the shaft 12 is rotated in the X direction, the nuts 11 on both sides independently move in the Y direction, and the hydrostatic bearing portion to which fluid is supplied accordingly. 6
And the support range of the hydrostatic bearing is expanded. When the load force is asymmetric with respect to the center of the roll, the supporting range of the hydrostatic bearing is also asymmetric accordingly.

According to the present embodiment, since the first support roll is supported by the two second support rolls, it is possible to stably support the work roll and the first support roll even if their diameters are extremely small. Of course, the second support roll may be one.

Further, in the present embodiment, the work roll supporting device is disposed only on one side in the rolling direction, but may be disposed on both sides in the rolling direction.
Further, in the present embodiment, the support device is disposed on each of the upper and lower work rolls 1. However, when the upper and lower work rolls having different diameters are used, the support device may be disposed only on the small-diameter work roll. .

Another embodiment is shown in FIG. The chamber is divided into a first chamber 21, a second chamber 23, and a third chamber 25 in a complicated manner,
Fluid is selectively supplied through the holes 22, 24 and 26. Hydrostatic bearing support range, when supplying fluid only to the first chamber 21,
In addition, the case where the fluid is supplied to the second chamber 23 and the case where the fluid is further supplied to the third chamber 25 are sequentially expanded. Of course, the room may be divided further finely. According to this embodiment, the structure of the hydrostatic bearing can be easily changed with a very simple structure. FIG. 7 shows another embodiment. A cylindrical shaft 30 is rotatably inserted into the cylindrical chamber 29, and the shaft 30 includes a bearing 28, a bearing box 27.
Are supported rotatably. The cylindrical outer surface of the shaft 30 is provided with a plurality of grooves 32 of different lengths in the longitudinal direction, each of which is formed by combining a hole 13 and a pitch on the circumference thereof. Through room 29. Therefore,
The fluid supplied from the hole 31 flows through the chamber 29 to the holes 34, 33, and 32, and further flows to the hydrostatic bearing 6 through the hole 13 connected to the groove 32. The hydrostatic bearing support area is rotated by rotating the shaft 30 by a driving device (not shown),
It is changed by increasing or decreasing the number of places where the hole 13 communicates with the hole 13. Further, a step 36 having a small diameter whose area increases or decreases in the longitudinal direction may be provided on the cylindrical outer surface of the shaft 35 shown in FIG. As shown in FIG. 9, a cylinder rod which slides in the cylinder 38 in the axial direction by hydraulic pressure or the like (not shown).
Insert the tip of 37 into the chamber 29
The support range of the hydrostatic bearing may be changed by the axial movement.

Until now, the method of changing the hydrostatic bearing support range to suppress the deflection of the work roll has been described, but conversely, by changing the hydrostatic bearing support range to actively flex the work roll Alternatively, the shape of the plate may be controlled. For example, when the support range of the hydrostatic bearing is narrowed in the embodiment of FIGS. 1 and 2, the work roll 1 bends in a convex direction when viewed from the support device side in FIG. 5, and the gap between the work rolls 1 is , Large at the ends and small at the center, resulting in a concave crown with a small central plate thickness. The shape becomes a middle-stretched shape because the center is stretched down. Further, when the support range of the hydrostatic bearing is widened, the work roll 1
Is deflected in the concave direction, and the gap between the two work rolls 1 is
Conversely, it becomes smaller at the ends and larger at the center, and the plate becomes a convex crown with a thicker plate at the center. The shape becomes an end-elongated shape because the end is expanded by being pressed down. Further, in the embodiment shown in FIG. 6, a complicated shape control is possible by further increasing the zone division, making the supplied fluid pressure variable as well as turning on and off, and arbitrarily changing the deflection of the work roll 1. Becomes Further, the support range of the hydrostatic bearing of the support roll can be easily changed, and the deflection of the work roll can be sufficiently suppressed, so that a plate having a small shape defect can be rolled.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to this invention, there exists an effect that the surface damage of a work roll can be suppressed and the replacement frequency of a hydrostatic bearing support part can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view of one embodiment of the present invention, and FIG.
FIG. 3 is a front view of the conventional example, FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. 3, and FIG. Explanatory diagram showing the relationship of deflection, sixth
FIG. 9 to FIG. 9 show sectional views of another embodiment of the present invention. 1 ... work roll, 4 ... first support roll, 5 ... second support roll, 6 ... hydrostatic bearing, 7 ... support frame.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshio Takakura 3-1-1, Sachimachi, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd. Hitachi Plant (72) Inventor Ichiro Maeno 3-1-1, Sachimachi, Hitachi-shi, Ibaraki No. 1 Inside Hitachi, Ltd. Hitachi Works (56) References JP-A-60-64709 (JP, A) JP-A-56-62603 (JP, A)

Claims (3)

(57) [Claims] 1. A rolling mill comprising: a pair of upper and lower work rolls reinforced by reinforcing rolls from above and below; and a plurality of support rolls for rollingly supporting at least one of the work rolls from a lateral direction. In the support roll, as the support roll, a first support roll of a cylindrical integral structure that directly rolls and supports the work roll, and a single or a plurality of cylindrical integrated structure that further rolls and supports the first support roll A rolling mill comprising: a support roll; and a support frame for supporting each of the second support rolls with a hydrostatic bearing. 2. The rolling mill according to claim 1, wherein the surface hardness of said first support roll is lower than the surface hardness of said work roll and said second support roll. 3. The rolling mill according to claim 1, further comprising means for changing a support range of said hydrostatic bearing of said second support roll.