RU2172653C1 - Roll mill stand - Google Patents

Abstract

FIELD: manufacture of rolled products. SUBSTANCE: roll mill stand has frame, horizontal rolls mounted in upper and lower chocks on bearings, and pressure screws. Upper chock arranged at side adjacent to roll tail is made in the form of figure defined by left-hand and right-hand U-shaped shoulders. Shoulder sides are joined in zone above first-order lines to form mid portion of chock with bearing bore. Wall is made thickening toward shoulders. Lower chock is formed in symmetry to upper chock. Thickness A of wall in vertical axis of bore is 0.05-0.25 of bore diameter. Extension is positioned above upper chock so that it abuts through pivot joints against shoulders. Support is positioned below lower chock. Damping gasket is arranged between chock and support surfaces and extension surface. Roll stand of such construction is preferably used in high dynamic duty pilger mills and provides for transfer to roller bearings in high dynamic duty stands. EFFECT: increased rigidity of roll stand and improved quality of rolled products due to distribution of total dynamic load over large area of roller bearing and to damping flexure of chock wall. 4 cl, 3 dwg

Description

 The invention relates to rolling production and can be used in mill stands with high dynamic and static loads on the rolling rolls, preferably in stands of a pilgrim mill.

State of the art
Known cushion roll roll stands / SU, AC, N 1037981, 21 21 31/02, 1983 /. The roll cushion comprises a housing with lateral, end and support sides, and a cylindrical bore for rolling bearings. At the end sides of the pillow between the bore and the supporting side interacting with the device for anti-bending the roll, on both sides of the vertical axis of the bore, at least three cylindrical holes are parallel and symmetrical, the axes of which are parallel to the axis of the bore.

 This invention allows to some extent to reduce the uneven distribution of the radial load on the rolling elements and to increase the durability of the bearings of the work rolls in sheet rolling stands quarto. However, such an invention cannot be used in the support rolls of the quarto and in two-roll stands with high dynamic loads on the bearings. The holes in the body of the cushion themselves are high stress concentrates and at high dynamic loads, for example in pilgerstan stands, cracking and failure of the roll cushion are possible. Deflection of the cushion wall from the vertical axis of the bore to the left and right to the holes is possible provided that the wall thickness is insignificant (plate effect) in the zone of the vertical axis of the bore and the proximity of the holes to the surface of the bore. However, under such conditions it is not possible to use the invention in pilgerstan cages, since due to high deformation from wall (plate) tension, a sharp change in the geometric shape of the hole in the zone of the vertical axis of the bore and in the area of the holes in the pillow body can occur and the bearing will fail.

 The lack of damping ability of the cushion wall in the area between the holes and the surface of the bore reduces the possibility of using the described invention in stands with high dynamic loads on the rolls and, accordingly, on the bearings.

 Known rolling mill pilgrim mill / Rolling production. Handbook / Ed. E. S. Rakatyan.- Publishing house of literature on non-ferrous and ferrous metallurgy, 1962, v. 1, p. 537-540 /, consisting of beds of horizontal calibrated rolling rolls installed in the upper and lower pillows, and pressure screws. The necks of the rolls are mounted on plain bearings. The pillow is made of the upper part with liners and the suspension with liners, forming a complete pillow with a plain bearing.

 A disadvantage of the known rolling stand of pilgerstan is the short bearing life due to the fact that at high cyclic dynamic loads characteristic of the pilger process, the sliding bearing is subjected to a high load on the same, relatively small, section of the bearing shell, which causes wear , high deformation, due to low stiffness, and a change in the shape of the liner. This contributes to the formation of gaps and, accordingly, to a decrease in the quality of rental.

 Disclosure of the invention.

 The basis of the invention is the task by dispersing the effects of the entire dynamic load on a large area of the bearing cage along its perimeter by providing the necessary and sufficient damper deflection of the upper wall of the upper pillow, and thereby seizing with force sections of the outer cage of the bearing, to enable the transition to bearings rolling in working stands with high dynamic loads and to increase rigidity, the service life of bearing assemblies while improving the quality of rolling ata.

 The problem is solved in that in a rolling stand, preferably pilgerstan, containing a bed, horizontal rolls installed in the upper and lower pillows, bearings and pressure screws, according to the invention, the upper pillow from the side of the shanks of the rolls is made in the form of a figure, the end sections of which are made in the form of shoulders of a U-shape, and the middle section of the pillow with a bore under the radial rolling bearing is formed by lines above the first order, directed to the sides from the vertical axis of the pillow and yayuschimi opposite yaw cushion U-shaped shoulders, the middle portion of the top wall is formed with a thickening, proportional to the distance between the curves of the first order, i.e. between the line of the outer surface of the middle wall of the pillow and the curve formed by the radius of the bore towards the shoulder mating portions symmetrically with respect to the vertical axis of the bore, the shape of the lower pillow mirrors the shape of the upper pillow, the thickness of the upper wall of the upper pillow and the lower wall of the lower pillow along the vertical axis of the bore is 0.05-0.25 of the diameter of the bore under the bearing, an extension is placed above the upper cushion, a stand is placed under the lower cushion, while the extension rests on the shoulder cushions through cylindrical hinges, arranged in bores of extensions, to form a gap between the adapter and the upper surfaces of the cushion and the bottom cushion supported on the support through cylindrical hinges to form a gap between the lower surfaces of the cushion and the base.

 Due to the improved design of the rolling stand due to the shape of the pillows formed by U-shaped shoulders, the sides of which are interconnected relative to the vertical axis of the pillow by lines of order higher than the first, forming the middle section of the pillow with a bore under the rolling bearing, it was possible to transfer the pressure of the screw to the sections of the pillow outside areas of location of the rolling bearing. The execution of the surface of the middle upper portion of the pillow on an order curve above the first and, accordingly, the thickening of the wall of the middle portion from the vertical axis of the pillow to the sides to the mating portions with the sides of the shoulders in proportion to the change in the distance between the order curves above the first one, provides a transfer of force to the outer race of the bearing, gradually increasing from the vertical axis pillows to the shoulders. In the event of dynamic loads on the rolling rolls, the bearing force is distributed over two sections of the sector of the angle α, in the areas of the rays of the angle α, thereby increasing the number of bearing rollers that absorb the total load on the bearing. This is ensured by bending the upper wall of the upper cushion and the lower wall of the lower cushion when creating preliminary efforts on the shoulders with a compression screw and at the time of peak dynamic loads on the rolling rolls. Bending of the upper wall of the upper pillow and the lower wall of the lower pillow is possible with the thickness of the walls of the pillows along the vertical axis of the bore under the bearing, equal to 0.05-0.25 of the diameter of the bore.

 When the wall thickness is less than 0.05 of the diameter of the bore under the rolling bearing for stands that accept high dynamic loads, the pilgerstan stand, for example, when the diameter of the neck of the roll and, accordingly, the bore under the rolling bearing is 700 mm, the wall thickness of the upper section of the upper pillow is on the vertical axis boring will be less than 35 mm.

 The yield strength of the cushion material, for example, steel 50, is 275 MPa. With a thickness of less than 0.05 of the diameter of the bore, the tensile force of the outer surface of the wall in the area of the vertical axis of the bore creates stresses close in magnitude and yield strength of the material.

 Reducing the wall thickness of less than 0.05 of the diameter of the bore is undesirable, because it can break in the zone of the vertical axis and the bearing will fail.

 When using a cushion material of carbon steels, for example 30 XC, the yield strength increases, however, given the cyclical load on the bearings and the cyclic bending of the middle part of the cushion at peak times, the thickness of the upper wall of the upper cushion should not be less than 0.05 of the diameter of the bore under the bearing.

 With an increase in the wall thickness of the upper portion of the upper pillow in the zone of the vertical axis of the wiring more than 0.25 of the diameter of the bore for the bearing (more than 140 mm for pilgerstan), it is undesirable, since the force on the outer race of the bearing is distributed locally in small sections of the angle sector α and not increases the area of contact pressure on the rolling body - the bearing rollers and the wall tend to the functions of the plate and wall bending will be undesirable.

 Placing the extension above the upper cushion and the stand under the lower cushion with surfaces facing them, repeating their shape and in contact with the pillows in the zones of the shoulders through cylindrical hinges, makes it possible to transfer forces from the push-screw mechanism directly to the sections of the shoulders in the area of the hinges.

 Due to the presence of hinges, due to their height and the height of the bore in the extensions and supports between the surfaces of the extension and the upper pillow, and the stand and the lower pillow, gaps are formed that contribute to the implementation of the damper deflection of the pillow walls.

 The presence of cylindrical joints hinging the force of the pressure screws on the pillows provides the possibility of turning the pillows in the axial plane during the deflection of the rolls at the time of peak loads, which ensures uniform distribution of loads on the radial bearings along the length of the neck of the roll and increases the durability of the bearing.

 The above set of features of the claimed rolling stand is sufficient in all cases to which the scope of legal protection applies.

 In addition, the inventive rolling stand has other distinctive features that develop, complement and characterize the invention in some cases of its implementation and use.

The location of the upper wall of the middle section of the upper cushion and the lower wall of this section of the lower cushion in sectors of the angle α - 60-120 ^o with the peaks in the centers of the bores under the rolling bearing and the bisectors of the angles passing along the vertical axis of the bore is due to the following factors.

 The dispersion of the load on the bearing in the sector of the angle α positively affects the operation of the bearing, its durability, the contact pressure area of the bearing rollers on the surface of the cages increases, and the load on each bearing roller decreases accordingly. Prerequisites are created for use in stands with dynamic loads, for example in pilgerstans, of rolling bearings instead of bearings used in similar stands. This ensures stable rigidity of the roll stand stands and high quality rolled products.

When the angle α is less than 60 ^{o, the} main force on the outer race of the bearing will be transmitted in the sector of this angle α, that is, the area of contact pressure on the rolling element of the bearing will actually decrease, the number of rolling bodies - rollers that absorb the load will decrease and the contact pressure will increase significantly rollers. At high dynamic loads, this can cause deformation of the bearing race.

When the angle α is more than 120 ^{o, the} distribution of forces on the outer race of the bearing occurs in an area close to the horizontal axis of the bearing, which negatively affects the operation of the bearing rollers, jamming of the rollers in the bearing race is possible. In addition, the width of the pillow increases and the height of the shoulders decreases and their bending is possible, which is unacceptable.

 In addition, according to the invention, the wall thickness of the pillows in the sections along the rays of the angle α is 1.1-2.5 of the wall thickness of the pillow along the vertical axis of the bore under the rolling bearing.

A uniform thickening of the wall of the upper middle section of the upper pillow and the lower wall of the lower pillow to the indicated values is necessary to create a uniform distribution of efforts on the bearing race over sections of the angle sector α = 60-120 ^o lying in the area of its rays. This provides a uniform load on the rolling element of the bearing, increasing the number of rolling elements involved in the transfer of force to the bearing race.

When the wall thickness of the pillow by the rays of the angle α is less than 1.1 the wall thickness of the upper middle section of the upper pillow along the vertical axis of the bore bisector of the angle α, the local areas of effort on the outer race of the bearing along the rays of the angle α are significantly reduced and the maximum force approaches the horizontal axis of the bearing at α = 100-120 ^o , which is undesirable, since jamming of the rolling elements in the bearing race is possible.

 When the thickness of the cushion wall along the rays of the angle α is more than 2.5 the wall thickness of the upper middle section along the vertical axis of the bore, it is necessary to increase the width of the shoulders, which is undesirable, and the force zone will approach the top of the wall in the zone of the vertical axis of the bore, which reduces the load distribution area by a larger the number of bodies of rotation of the bearing.

 In addition, according to the invention, the gap between the surfaces of the pillow and extension and pillow and stand is 0.05-0.2 wall thickness of the middle part of the pillow along the vertical axis of the bore under the rolling bearing and damper pads are placed in the gap.

 The gap is necessary to change the shape of the pillow wall at the moments of the distribution of forces along the right and left sectors of the outer race of the bearing, when bending forces occur on the inner surfaces of the pillow wall in the areas of the rays of the angle α and the outer surface of the pillow wall in the zone of the vertical axis of the bore under the bearing.

 Placing a damper pad in the gap is necessary to smooth tensile forces at the moment of peak loads and to exclude shock load on the bearing.

 With a gap of less than 0.05 of the pillow wall thickness along the vertical axis of the bore, it is difficult to smooth out shock loads, since a thin gasket has a small damping property, and an increase in the gap of more than 0.2 of the pillow wall thickness is undesirable, since distortion of the shape of the outer race of the bearing is possible.

 A brief description of the drawings.

 In FIG. 1 shows a rolling stand on the side of the shanks of the rolling rolls; in FIG. 2 - rolling stand on the rolling side; in FIG. 3 - upper cushion with diagrams of the distribution of loads on rolling bearings.

 An embodiment of the invention.

 The device consists of a bed 1 (Fig. 1,2), horizontal rolls 2, which are installed in the upper and lower pillows 3,4 on the radial rolling bearings 5, placed in the bores 6 of the pillows 3,4.

The upper pillow 3 from the side of the shanks of the rolls 2 is a figure formed by the left and right sections - shoulders 7.8 U-shaped, the sides of which, oppositely directed to each other relative to the vertical axis of the bore 6, are interconnected at points a and "c" (Fig. 3) with lines 9 above the first order, forming the middle section of the pillow 3 with a bore 6 under the rolling bearing 5. The upper wall 10 of the middle section of the upper pillow 3 lies in a sector of angle α equal to 60-120 ^o , the rays of which diverge from the vertex lying in the center of the axis along of the rose 5 up and to the sides to the points “a” and “b” (Fig. 3) of the line connecting with the sides of the shoulders 7.8, with the bisector of the angle α passing along the vertical axis of the bore 6. The wall 10 of the pillow 3 is made with a thickening proportional to the distances between the order curves are higher than the first, symmetrically from the vertical axis of the bore 6 to the points "a" and "c" of the pair with the shoulders 7.8.

 The wall thickness 10 of the upper pillow 3 and the lower wall of the lower pillow 4 along the vertical axis of the bore 6 is 0.05-0.25 diameter of the bore 6.

 The shape of the lower cushion 4 mirrors the shape of the upper cushion 3.

 The extension 12 is located above the upper cushion 3 under the pressure screw 11, and the stand 13 is located under the lower cushion 4. The extensions 12 are supported on the shoulders 7.8 of the cushion 3 through cylindrical hinges 14, forming a gap 15 between the surface of the extension 12, repeating the shape of the surface of the cushion 3 and cushion surface 3.

 The lower pillow 4 is supported by shoulders 7.8 on the stand 13 through cylindrical hinges 16, forming a gap 15 between the surfaces of the pillow 4 and stand 13.

 The hinges 14 are freely fixed in the bores of the extension 12 with coupling bolts 17, while simultaneously securing the cushion 3 to the extension 12 with the possibility of rotation of the cushion 3 in the axial plane during bending of the rolls 2.

 The gap 15 between the surfaces of the pillow 3.4 extension 12 and stand 13 is 0.05-0.2 thickness "A" of the wall 10 along the vertical axis of the bore 6 under the bearing 5.

 Damping gaskets are installed in the gaps, for example, a manganese-copper alloy having a damping property.

The thickness of the wall 10 of the pillows 3.4 in the areas of the rays of the angle α = 60-120 ^o is 1.1-2.5 thickness "A" of the wall 10 along the vertical axis of the bore 6.

 The lower surface 18 of the wall 10 of the pillow 3 and the upper surface of the wall 10 of the pillow 4 are made in the form of trapezium with smaller bases facing each other.

 Between the shoulders 7.8 of the lower cushion 4 and the stops 19 are installed hydraulic cylinders 20 of the pillow.

 The thrust mechanism of the upper cushion 3 in FIG. not shown.

In FIG. 3 shows a diagram 21 of the distribution of load on the bearing of the prototype and diagram 22 of the distribution of load on the bearing of the proposed rolling mill at m / "A" = 2.0 and α = 120 ^o .

 Assembly of the bearing assemblies of the rolling stand is as follows. Cassette sleeves are put on work rolls 2 (not shown in FIG.), On which pillows 3,4 with four-row roller bearings are mounted 5. On the surface of the upper pillow 3 and on the surface of the stand 13, spacers, for example, of Mn-Cu alloy, are installed, with high damping ability, a thickness of 0.05-0.2 thickness "A" - wall 10 of the upper pillow 3.

 The pillow 3 is connected to the extension 12 with coupling bolts 17, having previously installed in the bores of the extension 12 and the support 13 cylindrical hinged inserts 14.16. The height of the hinge is greater than the height of the bore by the amount of the gap 15. Then tighten the nuts of the coupling bolts 17 with a force sufficient to ensure axial freedom of the pillow 3 and the bending of the rolls 2 and pressing the gasket to the surface between the pillow 3 and extension 12.

 After installing the bottom cushion 4 on the stand 13 with hinged inserts 16 include a spacer mechanism 20 of the pillow 4, while providing a pressing force of the pillow 4 through the liners 16 to the stand 13.

 Rolling mill works as follows. When rolling the workpiece, for example, on pilgerstan with the front cone (striker) of the rolls colibra 2, the main deformation occurs. Rolls 2 capture a portion of a sleeve worn on a mandrel (not shown in FIG.), Followed by rolling of a portion of the sleeve.

 At the moment of capture of the liner portion, a humming cone hits the liner. This impact is transmitted through the necks of the rolls 2 to the bearing 5. The load on the outer race of the bearing 6 is transmitted through the rollers to the right and left zones of the angle sector α. Thus there is an additional bending of the walls 10 of the pillows 3,4 and an additional redistribution of the load on most of the inner surfaces of the outer casing. Due to the damping pads with a small change in the range of the gap 15 and the bending of the pillows, the shock load on the bearings 5 is smoothed, which provides increased resistance of the bearings 5.

 At the moment of dynamic loading, the axial deflection of the rolls 2 occurs. The pillows 3,4 rotate along the axis of rolling along the surfaces of the cylindrical liners 14,16, while maintaining parallelism with the axes of the bearings 5, as well as rigidity along the entire length of the bearings 5.

Industrial use
The proposed improved rolling stand can be used on mills with high static and dynamic loads - Pilgerstan, and will ensure the production of rolled products, for example, pipes of high accuracy of geometric dimensions, due to the transition to radial rolling bearings instead of plain bearings and increasing the rigidity of the stand.

Claims (4)

 1. A rolling stand, preferably a pilgerstan, containing a bed, horizontal rolls installed in the upper and lower pillows on bearings, and pressure screws, characterized in that the upper pillow on the side of the roll shanks is made in the form of a figure, the end sections of which are made in the form of shoulders U-shaped, and the middle section of the pillow with a bore under the radial rolling bearing is formed by lines above the first order, directed to the sides from the vertical axis of the pillow and connecting opposite relative to the vertical axis of the pillow side of the U-shaped shoulders, while the upper wall of the middle section is made with a thickening proportional to the distance between the curves above the first order, i.e. between the line of the outer surface of the middle wall of the pillow and the curve formed by the radius of the bore towards the shoulder mating portions symmetrically with respect to the vertical axis of the bore, the shape of the lower pillow mirrors the shape of the upper pillow, the thickness of the upper wall of the upper pillow and the lower wall of the lower pillow along the vertical axis of the bore is 0.05 - 0.25 of the diameter of the bore under the bearing, an extension is placed above the upper cushion, a stand is placed under the lower cushion, while the extension rests on the shoulders and cushions through cylindrical hinges arranged in bores adapter, to form a gap between the adapter and the upper surfaces of the cushion and the bottom cushion supported on the support through cylindrical hinges to form a gap between the lower surfaces of the cushion and the base. 2. The rolling stand according to claim 1, characterized in that the upper wall of the middle section of the lower cushion and the lower wall of the middle section of the lower cushion lie in the sector of the angle α = 60 - 120 ^o , with vertices in the centers of the bores for rolling bearings and with bisectors, passing along the vertical axes of the bore.  3. A rolling stand, characterized in that the wall thickness of the pillows in the sections along the rays of the angle α is 1.1 to 2.5 wall thickness along the vertical axis of the bore under the rolling bearing.  4. The rolling stand according to claim 1, characterized in that the gap between the surfaces of the pillows and extensions and stands is 0.05 - 0.2 of the wall thickness of the middle part of the pillow along the vertical axis of the bore under the bearing, and damper gaskets are placed in the gap.

Images