JPS5849330B2 - Method for reducing axial fluctuation of rolling rolls - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for reducing axial fluctuations of mill rolls during rolling to a minimum of 1.

Rolling by a rolling mill can be roughly divided into flat plate materials and shaped materials.

In any of these cases, it is well known that the movement of the rolling rolls in the axial direction has many negative effects on the quality of the material to be rolled, including its shape and dimensions.

For example, when rolling a plate material, if the horizontal roll moves in the axial direction, shape defects such as camber will occur.On the other hand, if the horizontal roll and rigid roll move in the axial direction when rolling a section, dimensional defects in the cross section of each part will occur. In addition, shape defects such as poor perpendicularity and bending occur.

The main cause of roll axial fluctuations that cause such serious defects is the mechanical structural play in the connection between the roll chock and the roll. Measures have been taken.

These measures include improving the fastening method between the chock and roll, improving the axial rigidity of the stand and chock, using thrust bearings, and adopting a keeper plate gap adjustment mechanism that fixes the chock to the stand. The aim was to make structural improvements to fix the fluctuations in the roll axis direction.

However, in a structure that includes this type of rotating body, some play is unavoidable, and even if this type of measure is taken, the play will still be around 0.3 to 3.0 degrees. The current situation is that we do not get any.

The present inventors conducted a static and dynamic investigation and analysis of the roll axis direction in the current chock structure in order to reduce fluctuations in the roll axis direction due to mechanical play that is unavoidable in conventional techniques.

As a result, when a load is gradually applied to the roll itself in one direction, the roll's axial fluctuation is large and unstable when the added load is small, but once it exceeds a certain value, the roll's axial fluctuation becomes extremely small. I discovered something.

In other words, at a constant load of 1, the roll will fluctuate in the axial direction within the range of the rotation clearance due to the influence of the mechanical play, but if a greater load is applied to the roll, the fluctuation in the roll axial direction will be determined by the mechanical structure. This characteristic corresponds to the thrust stiffness itself, which is very small.

The present invention was made based on the above findings, and the gist thereof is as follows.

That is, the invention of the method of the present invention is based on a rolling mill in which a constant and unidirectional axial load sufficient to resist the axial reaction force generated on the roll during rolling is applied to the end face of the roll on the non-driving side. This is a method for reducing axial fluctuation of a rolling roll, which is characterized in that rolling is performed at a rolling speed.

FIG. 1 shows a chock structure on the non-drive side of a rolling mill currently in use.

1 is a stand, 2 is a horizontal roll, and 3 is a choke.

A radial bearing 4 is interposed between the horizontal roll 2 and the chock 30, and a neck ring 5 is provided at the neck portion of the water roller 2, and a thrust bearing 6 is provided at the narrow diameter portion. An end ring 7 is fitted and fixed thereto, and is fastened with an adjusting nut 8.

The movement of the horizontal roll 2 in the axial direction is stopped by supporting the outer ring of the thrust bearing 6 with the end plate 9.

This end plate 9 is bolted to the chock main body 3 as shown in the figure. In the figure, reference numerals 10 and 10' indicate turnbuckles for adjusting the roll axis of the chock.

FIG. 2 shows an example of an experiment conducted by the present inventors using a currently commonly used chock structure as shown in FIG. 1 above.

In FIG. 2, the vertical axis shows the axial load P on the horizontal roll, and the horizontal axis shows the axial variation ε of the horizontal roll.

During normal rolling operations, no additional load is applied to the horizontal roll shafts, so if a thrust load P' is generated during rolling, an axis fluctuation ε' will occur within the range of mechanical play in the axial direction.

Region a indicates the above-mentioned normal rolling region.

On the other hand, region b indicates a horizontal roll axial direction variation region according to the present invention, and even if the thrust generated load P" is generated to approximately the same extent as the above-mentioned P', the variation amount ε" is extremely small.

That is, for horizontal roll, the limit thrust force P.

If rolling is carried out under the above conditions and with an axial load C sufficiently large to withstand the thrust load P" generated during rolling, the best result is that only the elastic strain of the chock acts, unaffected by mechanical play. This enables rolling in the axially variable characteristic region.

The present invention can be applied not only to horizontal rolls used in flat plate rolling and shape rolling, but also to rigid rolls used in steel bar rolling.

Furthermore, the direction of the load applied to the roll axis can be either direction.
For example, it may be of a type in which the end face of the roll shaft is pressed or a type in which the end of the roll is pulled.

FIGS. 3 and 4 show two examples of implementations of apparatus for carrying out the present invention.

First, referring to FIG. 3, the same numerals as in FIG. 1 represent the same parts, so the explanation will be omitted. 11 indicates a pressing device for the non-drive side end surface of the horizontal roll 2 by a hydraulic cylinder. The hydraulic cylinder 11 is supported by a support beam 12 bolted to the chock 3.

This support beam 12 also serves as the end plate 9 in FIG.

13 is a spacer ring installed on the end surface of the horizontal roll 2; 14 is a bearing for the hydraulic cylinder 11; the pressing force generated by the hydraulic cylinder 11 acts on the end surface of the horizontal roll 2 via the bearing 14 and the spacer ring 13.

15 is a thrust adjustment key.

In the configuration shown in FIG. 3, when a constant pressing force of C is applied to the end surface of the roll by the hydraulic cylinder 11, the axial position of the horizontal roll moves in the +ε direction due to the mechanical play and the roll axis generated during rolling. This results in a variation d sufficient to withstand the directional load.

Mechanical play in this state is accumulated in the opposite direction to the direction of the pressure C.

That is, when the roll 2 moves in its axial direction, the Asia Sting nut 8 that engages with the end ring 7 that fits into the end of the roll moves the inner ring of the thrust bearing 6 into one of the rolls.
Pressed against the drive side, inside the thrust bearing 6, the roll side bearing (rollers) is in close contact with the inner ring, bringing the play close to zero, and at the same time the chock side bearing (rollers) is pressed against the drive side.
separates from the inner circle.

Therefore, the mechanical play in the axial direction of the roll 2 (the minute play between the end ring and the adjusting nut, the minute play between the spacer ring and the thrust bearing, and the play within the thrust bearing) converges to zero.

If rolling is carried out under such conditions and the thrust load P" is generated in the same direction as the pressing force direction, the mechanical play is accumulated in the opposite direction as described above, so the effect of the play is exerted. There is no fluctuation in the roll axis direction due to this.

On the other hand, even if a thrust load -P" is generated in the opposite direction to the pressing direction, as long as Po+P"<C is maintained, the effect of mechanical play will be exerted, and therefore, there will be no fluctuation in the roll axis direction due to this.

That is, even if a thrust load is generated in any direction, fluctuations in the roll axis direction due to mechanical play can be effectively prevented.

Similarly, if there is a difference in the mechanical play between the upper and lower sides of the horizontal roll, and if a difference occurs in the axial movement amount d between the upper and lower sides of the horizontal roll due to implementation of the present invention, the thrust adjustment in FIG. The position in the roll axis direction can be arbitrarily corrected by replacing the key 15 and adjusting the turnbuckle 10.

FIG. 4 shows a modified embodiment of FIG. 3, in which the support beam 1
2 is provided directly on the chock body 3, and the effect exactly the same as that shown in FIG. 3 can be obtained.

As described above, the present invention can easily minimize the fluctuation in the roll axis direction by only partially modifying the existing equipment, and can greatly contribute to improving the quality and accuracy of rolled materials.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing the chock structure of a rolling mill commonly used at present, Fig. 2 is a characteristic diagram of horizontal roll axial fluctuation, and Figs. 3 and 4 are cross-sectional views of embodiments of the present invention. It is a diagram. 1...Stand, 2...Horizontal roll, 3...Chock, 4...Radial bearing, 5...Neck ring, 6...Thrust bearing, 7...End ring, 8...・Adjusting nut, 9... End plate, 10... Turnbuckle 11... Hydraulic cylinder, 12... Support beam, 13...
Spacer ring, 14...Bearing, 15...
Thrust adjustment key.

Claims (1)

[Claims] 1. Rolling is carried out in a state where a constant and unidirectional axial load sufficient to resist the axial reaction force generated on the roll during rolling is applied to the end face of the roll on the non-driving side of the rolling mill. A method for reducing axial fluctuation of a rolling roll, characterized in that: 2. The method for reducing axial fluctuation of a mill roll according to claim 1, wherein a pressing force in the axial direction of the roll is applied to the end face of the roll on the non-driving side.