RU2319562C2 - Prestressed rolling stand - Google Patents

Abstract

FIELD: rolled stock production, possibly in sheet rolling, bar rolling and tube rolling mills.

SUBSTANCE: rolling stand includes foundation, lower and upper rolling rolls. Chocks of lower rolling roll with radial and thrust bearing assemblies are mounted on foundation. Chocks of upper rolling roll with radial and thrust bearing assemblies are mounted on chocks of lower rolling roll. Upper traverse bar is fixed to chocks of upper roll. Tightening bolts with nuts and embedded dowels are used for joining upper traverse bar with foundation. Radial motion mechanism of upper roll is arranged in chocks of upper roll. Axial motion mechanism of lower roll is arranged in chocks of lower roll. Axis of radial bearing assembly in each chock is turned relative to axis of abutted rolling roll by angle determined according to calculation formula.

EFFECT: lowered metal consumption of rolling mill, reduced labor consumption for manufacturing and mounting rolling mill, increased useful time period of bearing assemblies of rolling rolls, decreased expenses for rolling mill operation.

2 cl, 4 dwg

Description

The invention relates to the field of production of rolled products and can be used to increase the profitability of rolling mills by equipping them with working stands of the proposed design. By increasing the load capacity of the bearings of the work rolls, the weight of the main equipment of the mill and, accordingly, its cost are reduced.

Known prestressed rolling stand containing a base, lower and upper rolling rolls with pillows, mounted on the base with the possibility of self-installation, coupling hydraulic cylinders with embedded elements, connecting the base with pillows of the upper work roll, an eccentric spacer mechanism for radial movement of the upper work roll located between the pillows upper and lower work rolls (1).

One of the features of this stand is that the eccentric spacer mechanism installed between the lower and upper pillows during the rolling process is unloaded from the prestressing force of the stand and prevents the pillows from self-installation slightly.

The disadvantage of the above rolling stand is that the self-alignment means in the interface between the pillows and the base and the coupling bolts are loaded with the pre-load of the stand and the accompanying frictional moments that counteract the moments of self-alignment of the bearings. Considering that the pre-stress force significantly exceeds the maximum rolling force, the presence of the said self-installation means does not eliminate the distortions in the bearings and does not increase the load capacity of the rolling stand.

Another disadvantage that reduces the reliability of the said stand is that the eccentric spacer mechanism is in the area affected by temperature, coolant, and dusty scale.

The closest in technical essence and the achieved result (prototype) to the claimed stand is a prestressed rolling stand containing a base, lower and upper work rolls, pillows of the lower work roll with radial and thrust bearings, mounted motionless on the base, pillows of the upper work roll with radial and thrust bearings mounted motionless on the pillows of the lower work roll, the upper beam mounted motionless on the pillows of the upper roll, coupling bolts with a nut and mortgage dowels and connecting the upper yoke to the base, the mechanism of the radial displacement of the upper roll disposed in the cushions of the upper roll and the mechanism of axial movement of the lower roll, disposed in the cushions of the lower roll (2) (p.146 ... 153).

The peculiarity of this stand is that the pillows in which the bearings of the rolling rolls are mounted are rigidly fixed in a predetermined position using the base, the upper crosshead and the coupling bolts, which, with high precision manufacturing of all parts, allows to minimize mounting distortions in the bearings.

The disadvantage of this stand is that at high loads in the bearings of the rolling rolls, distortions occur due to the deflection of the rolling rolls, which reduces the load capacity of the stand and the durability of the bearings.

The aim of the invention is to increase the load capacity of the rolling stand and increase the durability of the bearings of the rolling rolls.

This goal is achieved due to the fact that in a prestressed rolling stand containing a base, lower and upper work rolls, pillows of the lower work roll with radial and thrust bearings, mounted motionless on the base, pillows of the upper work roll with radial and thrust bearings, mounted motionless on the pillows of the lower work roll, the upper traverse mounted motionless on the pillows of the upper roll, the coupling bolts with nuts and embedded keys, connecting the upper traverse to the main The mechanism of the radial movement of the upper roll placed in the pillows of the upper roll, and the axial movement of the lower roll placed in the pillows of the lower roll. Moreover, according to the invention, the axis of the radial bearing in each pillow, directed from the axle of the work roll to the barrel, is rotated relative to the axis of the mating roll in the direction of the rolling force vector by an angle:

where R _pr.n - nominal rolling force;

E and G are the tensile and shear moduli of elasticity;

D and d are the diameter of the barrel and the diameter of the trunnion of the work roll;

A is the distance between the supports of the rolling roll;

L is the barrel length;

l is the length of the bearing.

The diametrical clearance in the radial bearings of the work rolls under the condition that there is no “parasitic” load in the bearing at idle and no radial play in the coupling of the journal with the bearing is equal to:

where l is the length of the bearing;

φ is the angle between the axis of the work roll and the axis of the bearing directed from the journal of the work roll to the barrel.

Figure 1 shows a longitudinal section of a prestressed rolling stand of the proposed design; figure 2 is a section bB in figure 1; figure 3 - place In figure 1 (the pairing of the bearing with the axle of the rolling roll without load); in Fig.4 - place B in Fig.1 (pairing of the bearing with the journal of the rolling roll under load).

The prestressed stand of the proposed design (Figs. 1, 2) contains a base 1, a lower work roll 2, an upper roll 3. Pillows 4, 5 of the lower work roll with radial and thrust bearings 6, 7 are mounted on the base 1 using the clips 8 motionless. Pillows 9, 10 of the upper work roll with radial and thrust bearings 6, 7 are mounted on the pillows of the lower work roll using the clamps 11 motionless.

The upper beam 12 is mounted on the pillows of the upper work roll using the clips 13 motionless. Coupling bolts 14 with nuts 15, washers 16 and embedded keys 17 connect the upper beam 12 to the base 1.

The mechanism of radial movement of the upper roll, including eccentric bushings 18, 19 and worm gears 20, 21, is located in the pillows 9, 10 of the upper roll. At the same time, for coarse adjustment of the position of the upper roll, a pack of gaskets 22 is installed between the pillows of the lower roll and the pillows of the upper roll.

The axial movement of the lower roll, including a screw 23 and a hydraulic cylinder 24, is located in the pillows 4, 5 of the lower work roll.

The assembly of the stand is carried out in the following sequence: the base 1 is installed stationary in the line of the working stand or on an intermediate lodgement. Four latches 8 are installed in the slots of the base 1.

The lower roll 2 with pillows 4, 5 and the axial movement mechanism of the lower roll 23, 24 is assembled on a specialized stand and installed on the base 1, while aligning the latches 8 with the slots in the pillows 4, 5. Four latches 11 are installed in the slots in the pillows 4, 5. On the pillows 4, 5 install a package of gaskets 22, while the thickness of the package is determined depending on the diameter of the barrel of the work rolls.

The upper roll with pillows 9, 10 and the mechanism for radial movement of the upper roll, including eccentric bushings 18, 19 and worm gears 20, 21, is assembled on a specialized stand and installed on the pillows of the lower work roll, combining the slots on the pillows of the upper roll with the latches 11. Four the retainer 13 is installed in the nests in the pillows 9, 10 of the upper roll.

The upper traverse 12 together with the coupling bolts 14, nuts 15 and washers 16 are mounted on the pillows 9, 10 of the upper roll, while aligning the latches 13 with the slots in the traverse 12. Put four embedded keys 13 and tighten the nuts 15 until the compressive force of the upper working pillows is reached a roll with cushions of a lower work roll exceeding the rolling force. Dismantling of the stand is carried out in the reverse order.

When the stand is operated without load (Fig. 3), the axis 25 of the bearing 6, directed from the journal pin to the barrel, is rotated relative to the axis 26 of the work roll 2 in the direction of the rolling force vector P _pr , by an angle φ, which is determined by formula (1) depending from the geometric parameters of the work roll and the nominal rolling force for a given mill stand. Moreover, between the friction surfaces 27, 28 of the bearing and the journal of the work roll there is a skew equal to the angle φ.

After application to the barrel of the roll rolling force P nominal _pr.n (1, 4) on a pin of the work roll 2 acts a uniformly distributed load q _n, which under the action of the elastic line 29 of the work roll 2, linearized at the place of contact with the bearing pin, will parallel to the axis 25 of the bearing 6. In this case, the trunnion of the work roll will rotate at the angle φ mentioned above, and the friction surfaces 27, 28, respectively, of the trunnion and bearing will contact without distortion, providing maximum load capacity of the rolling stand.

The invention in comparison with the prototype changes the functional dependence of the bias value on the magnitude of the rolling force.

In the prototype, the skew angle in the radial bearings is determined by the equation:

In the rolling stand of the proposed design, the skew angle in the radial bearings is determined by the equation:

where M is the stiffness modulus of the work roll;

R _pr.n - the nominal value of the rolling force;

P _CR - the actual value of the rolling force.

From equations (3, 4) it follows that in the prototype with an increase in the rolling force, the skew in the radial bearings increases, which significantly reduces the load capacity of such a stand.

In the rolling stand of the proposed design, with an increase in the rolling force, the distortions in the bearings decrease and with the nominal rolling force, the distortions in the radial bearings are zero, and the load capacity of the rolling stand will be equal to the nominal load capacity of the radial bearings.

Information sources

1. USSR copyright certificate No. 1031544A B21B 31/04.

2. A.N. Ivoditov, N.A. Toder “Design and modernization of high-quality rolling mills” M., Metallurgy, 1993

Claims (2)

1. A prestressed rolling stand comprising a base, lower and upper work rolls, cushions of the lower work roll with radial and thrust bearings fixedly mounted on the base, cushions of the upper work roll with radial and thrust bearings fixedly mounted on the cushions of the lower work roll, upper a cross-arm mounted motionless on the pillows of the upper roll, coupling bolts with nuts and embedded keys that connect the upper cross-arm to the base, the mechanism of radial movement of the top its roll placed in the pillows of the upper roll, and the axial movement of the lower roll placed in the pillows of the lower roll, characterized in that the axis of the radial bearing in each pillow, directed from the journal pin to the barrel, is rotated relative to the axis of the mating roll in the direction of the rolling force vector at an angle

where R _pr.n - nominal rolling force; E and G are the tensile and shear moduli, respectively; D and d are the diameter of the barrel and the diameter of the trunnion of the work roll, respectively; A is the distance between the supports of the rolling roll; L is the barrel length; l is the length of the bearing. 2. The rolling stand according to claim 1, characterized in that the diametrical clearance δ in the radial bearings is δ = 1 × sinφ.

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