JPS60255207A - Roll crossing type rolling mill - Google Patents

Abstract

PURPOSE:To reduce largely the pressure on the contacting face of a radial bearing and journal box and to prolong the bearing life by interposing an annular spacer between a flange for thrust receiving and radial bearing. CONSTITUTION:A flange 4 for thrust receiving is projected to the inner face of a journal box 1 supporting both ends of a work roll 101 and a radial bearing 3 is fitted to the inside of the flange 4 thereof. A thrust bearing 2 holding between a flange part 101a formed on the outer peripheral face of the work roll 101 in the outside of the flange 4 thereof is fitted. An annular spacer is interposed between the radial bearing 3 and flange 4. Consequently a high contacting face pressure is acted around the flange 4, but the radial bearing 3 is separated from the flange 4 at a certain distance due to the interposition of the annular spacer 5. The contacting face pressure of the radial bearing 3 and journal box 1 is thus reduced largely.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a roll-cross rolling mill equipped with thrust bearings and radial bearings, which suppresses wear of the bearing box and radial bearings and extends the life of the roll-cross rolling mill.

In recent years, there has been an increasing demand for improving the thickness accuracy of rolled products in the direction of the plate and extending the life of rolled products due to roll wear.

For this reason, the present applicant proposed a bare cross type four-high rolling mill as shown in Japanese Patent Application Nos. 53-138837 and 54-59327.

These rolling mills are equipped with a work roll vending device consisting of a left and right roll gap setting device and a hydraulic jack, and a bare cross mechanism is used to bend the upper work roll and upper back-up roll, and the lower work roll and lower back-up roll, respectively, in a horizontal plane. It is inclined at a required angle in the opposite direction to the direction perpendicular to the rolling direction.

However, in such a cross-roll rolling mill, the circumferential speed direction of the upper and lower work rolls and the advancing direction of the rolled material deviate by an amount equivalent to the inclination angle, which causes slippage in the roll axis direction, causing the upper and lower work rolls to Thrust forces in opposite directions are generated. This thrust force is applied to a normal rolling mill where the upper and lower roll axes are parallel (cross angle θ of a roll-cross type rolling mill).
It is much larger than -0.

Therefore, as shown in FIGS. 1 and 2, the conventional roll cross type rolling mill has a thrust bearing flange 4 protruding from the inner surface of the bearing box 1 that supports the upper and lower work rolls 101.
A radial bearing 3 is mounted on the inside of this flange 4, while a thrust bearing 2 is mounted on the outside of this flange 4 to sandwich a flange 101a formed on the circumferential surface of the work roll 101.

By the way, due to the mounting location and structural constraints of the work roll bearing box l, the upper and lower wall thicknesses are much thinner than the left and right wall thicknesses, as shown in Figures 1 and 2. Since the axial rigidity of the longitudinal section is not uniform due to the thrust receiving flange 4, it is thought that the distribution of the contact surface pressure p between the outer ring of the radial bearing 3 and the inner surface of the bearing box 1 becomes non-uniform during rolling. Therefore, the present inventors have investigated the relationship between the contact surface pressure p between the inner surface of the work roll bearing box 1 and the outer ring of the radial bearing 3 in the roll axis circumferential direction θ or the roll axis longitudinal direction t when the work roll pending force P acts. After calculating the distribution state, the radial bearing length t = 400m and the radial bearing inner diameter = 520vr as shown in Figures 6 and 8.
m, the radial bearing part of the flange 4 (point D) and the bearing box 1 (
The spring constant ratio at point E) was set to 2:1. Moreover, as shown in FIG. 4, the angle θ was calculated from the point farthest from the backup roll to the cloth in the diagram. As is clear from the results (d) and (e) shown in Figures 6 and 8, the contact surface pressure p is not uniform, especially at the point closest to the flange 4 (t=O) furthest from the backup roll. The maximum value (p = 1.8 ky/d) is taken at the point (θ≧0), and this value is the 6th
This is nearly twice the generally considered maximum value of the contact surface pressure shown in FIG.

In this way, the radial bearing 3 and the bearing box 1 are subject to extremely large contact pressures in the portions near the thrust bearing flange 4, which causes this portion to wear out relatively quickly, resulting in a very serious problem that the service life of the bearing box 1 is significantly reduced. There was a technical flaw.

The present invention has been made in view of the above-mentioned prior art, and its purpose is to improve the life of a cross-roll rolling mill equipped with a thrust bearing. The structure of the present invention to achieve such an object is to tilt the upper and lower work rolls in opposite directions perpendicular to the rolling direction in a horizontal plane, and to install thrust bearings and radial bearings in the bearing boxes that support both ends of the work rolls. In a roll cross type rolling mill in which a bearing is mounted and a thrust bearing flange, which is sandwiched between the thrust bearing and the radial bearing, is protruded from the inner surface of the bearing box, an annular shape is provided between the thrust bearing flange and the radial bearing. It is characterized by interposing a spacer.

EMBODIMENT OF THE INVENTION Hereinafter, the rolling mill of this invention will be explained in detail based on an Example.

In a cross-roll rolling mill in which the upper and lower work rolls are tilted in opposite directions with respect to the direction perpendicular to the rolling direction in a horizontal plane, thrust force due to the cross angle acts on the upper and lower work rolls. Work roll 10 as shown in
A thrust bearing flange 4 is provided protrudingly on the inner surface of the bearing box 1 that supports both ends of the bearing box 1 , and a radial bearing 3 is mounted on the inside of this flange 4 . However, in the present invention, excessive contact pressure is generated between the radial bearing 3 and the bearing box 1 due to the shape of the bearing box 1, etc. To prevent this, an annular spacer 5 is interposed between the radial bearing 3 and the thrust bearing flange 4. Here, the axial length t' of the annular spacer 5 is determined by the maximum value of the contact surface pressure between the bearing box 1 and the radial bearing 3 due to the roll pending cup P, as shown in FIGS. 6 and 8. It is desirable to determine the value to be equal to or less than the normal value shown in curve C in Figure 6 (example case 1 = 1.0 kf/mj).

Regarding the rolling mill of the present invention having the above configuration.

Calculate the distribution state of the contact surface pressure p between the inner surface of the work roll bearing box 1 and the outer ring of the radial bearing 3 in the roll shaft circumferential direction θ or [coal shaft longitudinal direction t] when the work roll pending force P acts. However, Figure 6,
The results shown in FIG. 8 were obtained. However, the setting conditions are the same as those described above. The results shown in both figures (a), (b) and (f) (as is clear from hl), the maximum value is thicker than the distribution curve (d) (gl) for the conventional bearing.
] low. Needless to say, there is no reason for this.

Since a high contact surface pressure acts near the thrust bearing flange 4, by interposing an annular spacer 5 of an appropriate length t' between the flange 4 and the radial bearing 3, the radial bearing 3 is This is because it extends a certain distance from the flange 4. still.

In FIGS. 5, 6, and 8, the dashed-dotted lines relate to the prior art, and the other lines relate to the present invention. Further, although the upper work roll bearing box is shown in FIGS. 4 and 7, the explanation of the lower work roll bearing box will be omitted since it has a similar structure.

As described above in detail based on the examples, the present invention can significantly reduce the contact surface pressure between the radial bearing and the bearing box, thereby extending the life of the bearing, reducing maintenance costs, and contributing to improved productivity. . It also has the advantage of being simple and inexpensive.

[Brief explanation of drawings]

Fig. 1 is a schematic front view showing the roll arrangement of a pair-cross type four-high rolling mill, Fig. 2 is a sectional view of essential parts of a conventional work roll bearing box taken along the line X-X in Fig. 1, and Fig. 3 4 is a sectional view of a main part of a work roll bearing box similar to FIG. 2 according to an embodiment of the present invention, and FIG. 4 is an end view of the upper work roll bearing box for explaining the starting position in the roll axis circumferential direction θ. , Figure 5 is A
-A, 13-B, C-C cross section, main part sectional view of the bearing box and radial bearing to show point E, and Figure 6 shows the contact surface pressure p and angle θ between the radial bearing and the bearing box. 7 is an end view of the upper work roll bearing box to show points F and G, and FIG. 8 is a graph showing the relationship between the contact surface pressure p between the radial bearing and the bearing box and the roll axial length t. It is an explanatory diagram for explaining correspondence. 1 in the drawing is the bearing box. 2 is the thrust bearing. 3 is a radial bearing. 4 is a thrust receiving flange, 5Fi spacer. 101 is a work roll, 102 is a backup roll, and 103 is a material to be rolled. p is work roll pending. W indicates the rolling direction of the rolling blade 2. Patent Applicant Mitsubishi Heavy Industries, Ltd. Patent Attorney Sub-Attorney Shibu Mitsuishi (and 1 other person) :l Go Q Old f1 Anchor 1 Taku 0 Den-0 (JT) :11 :lI.

Claims (1)

[Claims] The upper and lower work rolls are tilted in opposite directions in a horizontal plane with respect to the direction orthogonal to the rolling direction, and a thrust bearing and a radial bearing are installed in a bearing box that supports both ends of the work roll, and the thrust bearing and the radial bearing are mounted on a bearing box that supports both ends of the work roll. A roll cross rolling mill having a thrust receiving flange protruding from the inner surface of a bearing box, which is sandwiched between the thrust receiving flange and the radial bearing, characterized in that an annular spacer is interposed between the thrust receiving flange and the radial bearing. Roll cross rolling mill.