FR2809975A1 - ROLLER CAGE - Google Patents

Abstract

The invention relates to the rolling industry and can be used in cages with high dynamic loads. It relates to a rolling mill stand, preferably a pilgrim's step rolling mill. The rolling mill stand contains a frame (1), horizontal cylinders (2) installed in the upper and lower bearings (3, 4) on the bearings (5) and pressure screws (11). According to the invention, the bearing (3) on the side of the trunnions of the cylinders (2) is a figure defined by left and right shoulders (7, 8) having the shape of a "PI". The sides of the shoulders (7, 8) are connected by upper curved profiles (9), defining a medium section for the bearing (3), with bore (6) for the bearing and the wall (10) is made in directed bead towards the shoulders (7, 8). The shape of the lower pad (4) is the mirror image of the shape of the pad (3). The thickness "A" of the wall (10) on the vertical axis of the bore represents between 0.05 to 0.25 times the diameter of the bore (6). Above the bearing (3) is placed an extension (12) supported by hinges (14) on the shoulders (7, 8). Under the cushion (4) is placed a support (13). Between the surfaces of the bearings (3, 4) and of the support (13), and of the extension (12) there is a cushioning lining.

Description

ROLLER CAGE

  The invention relates to the rolling industry and can be applied to rolling mill stands with high dynamic and static loads on rolling rolls, preferably to rolling mill stands with pilgrim steps. We know rolling mill stands with pilgrim's steps - see npoKaTHoe npOM3BOACTBO, CnpaBO4HHK, TOM 1, 1962 r., No; peqaK 4zeR E.C. PaKaTRHa, IA13AaTenbcTEo nlaTepaTypbl no 4BeTHoI Ml 4epHoR MeTanypr [i4, c. 537-540

  (Prokatnoe Proizvodstvo Spravotchik, Tome 1, 1962., pod Redaktsiei E.S.

  Rakatiana, Izdatielstvo Literatouri po Tsvetnoi i Tchenoi Metalourguii, p. 537-540) -

  comprising frames for horizontal and calibrated rolling rolls, installed in upper and lower bearings, and pressure screws. The rolling cylinder journals are installed on bearings. The cushion consists of the upper part of the cushion and the lower support part of the cushion,

  thus creating in the assembled state the bearing of the sliding bearing.

  The shortcoming of the known pilgrim step rolling stand cages is the short life of the bearings, due to the fact that under the strong dynamic cyclic loads specific to the pilgrim step rolling process, a heavy load weighs on the sliding bearing on the same section of the bearing bearing, relatively small, which causes its wear and a strong deformation due to its low rigidity and the change in shape of the bearing. This contributes to the

  formation of games and, consequently, to the degradation of the quality of rolling.

  The problem posed by the invention is linked to the possibility of using sliding bearings in roller cages under high dynamic loads, and to the increase in the rigidity and the service life of the bearing blocks. This will at the same time lead to an improvement in the quality of rolling as a result of the distribution of all the dynamic load over a large area of the bearing hoop around its perimeter, taking into account the damping flexion.

  necessary and sufficient from the upper wall of the upper cushion.

  The above problem is solved by the cage of the rolling mill according to the invention, preferably a pilgrim's rolling mill, which has a frame receiving horizontal cylinders installed on bearings in upper and lower bearings, and pressure screws . On the side of the cylinder trunnions, the upper bearing has an "IT" shape, as defined in section by left and right shoulders. The bearings opposite with respect to the vertical axis have their sides connected to each other by curved profiles greater than the sides of the vertical axis of the bearing, by defining a medium section having a bore for a rolling bearing. The upper wall of the middle section includes a bead proportional to the distances between the curves of the upper surface of the middle wall of the bearing and the radius of the bore symmetrically to the vertical axis of the bore in the direction of the junction sections with the shoulders. The shape of the bottom pad is the mirror image of the shape of the top pad and the thickness of the top wall of the top pad and the bottom wall of the bottom pad on the vertical axis of

  the bore is between 0.05 to 0.25 times the diameter of the bore for the bearing.

  Above the upper pad is an extension and under the lower pad is a support based on the shoulders of the corresponding pads, by means of cylindrical hinges arranged in bores of the extension, forming a clearance between the surfaces of the extension and the surface upper cushion. Finally, the lower cushion is supported by the shoulders on the support by means of cylindrical hinges, forming a play

  between the surfaces of the lower pad and the support.

  Thanks to the improved structure of the rolling mill stand, due to the shape of the bearings created by the "r" shaped shoulders, the sides of which are connected to each other relative to the vertical axis of the bearing by the upper curved profiles, by forming a medium section of the bearing which has a bore for a rolling bearing, the force of the pressure screw on the sections of the bearing is brought out of the zone where the rolling bearing is placed. upper middle section of the pad in an upper curved profile and, also, the bead at the middle section of the vertical axis of the pad in the direction of the conjugate sections at the sides of the shoulders, are proportional to the variation of the distance between the upper curves, which transmits the force on the outer hoop of the bearing, which increases regularly from the vertical axis of the bearing to the shoulders. dynamic on the rolling rolls, the force on the bearings is distributed in section over the sector of angle a, in the radii of angle oc, thus increasing the number of rollers of the bearings receiving the total load. This is achieved by bending the wall of the upper bearing and the lower wall of the lower bearing, with the appearance of the preliminary forces on the shoulders by the pressure screw, at the time of the peak of the dynamic loads on the rolling mill rolls . Bending of the upper wall of the upper bearing and the lower wall of the lower bearing is only possible if the thickness of the walls of the bearings on the vertical axis of the bore for the bearing is equal to 0.05 to 0 , 25 times the diameter of the bore. For a wall thickness of less than 0.05 times the diameter of the bore for the rolling bearing, in cages receiving high dynamic loads, for example a rolling cage with pilgrim steps, having for example a diameter of cylinder journal and also bore for the rolling bearing equal to 700 mm, the wall thickness of the upper section of the bearing

  higher on the vertical axis will be less than 35 mm.

  The yield strength of the pad material, for example steel 50, is 275 Mpa. With a thickness of less than 0.05 times the diameter of the bore, the tensile force of the upper surface of the wall in the area of the vertical axis

  of the bore creates tensions close to the limit value of the elasticity of the material.

  Reducing the thickness of the wall to less than 0.05 times the diameter of the bore is therefore undesirable; it can destroy it in the area of

  the vertical axis and the bearing can be taken out of service.

  With the use as material for the bearing of carbon steels, for example 30 XC, the yield strength increases. However, taking into account the cyclic nature of the load on the bearings and the cyclic bending of the middle part of the bearing at the moments of peak loads, the thickness of the upper wall of the upper bearing must not be less than 0, 05 times the

  diameter of the bore for the bearing.

  Increasing the thickness of the wall of the upper section of the upper bearing in the area of the vertical axis of the bore to more than 0.25 times the diameter of the bore for the bearing (more than 140 mm for a pilgrim step rolling mill) is not desirable, since the force on the outer hoop of the bearing is distributed locally over the small sections of the sector of the angle ca. This does not increase the contact pressure surface on the bearing and roller bearings and the

  wall bending becomes undesirable.

  The arrangement of the extension above the upper bearing and the support under the lower bearing with the facing surfaces, reproducing their shape and coming into contact with the bearings in the areas of the shoulders by means of the cylindrical hinges, ensures the transmission of the forces pressure screw mechanism directly on the shoulder sections

in the hinge area.

  Thanks to the presence of the hinges, taking into account their height and the height of the bore in the extensions and in the supports between the surfaces of the extension and the upper pad, and of the support and the lower pad, it creates games which contribute to the achievement of bending

  cushioning of the bearing walls.

  The presence of the cylindrical hinges transmitting the force of the pressure screws on the bearings allows the bearings to tilt in the axial plane during the bending of the rolling rolls at the time of peak loads, which guarantees a uniform distribution of loads on the bearings radial over the length of the cylinder trunnion and increases the service life of the bearing. All of the distinctive features of the rolling stand according to the invention are

  sufficient in all cases concerned by the scope of protection.

  In addition, the rolling stand according to the invention may have other distinctive characteristics which develop and complete the invention, in relation

  with certain forms of execution and use.

  The position of the upper wall of the middle section of the upper bearing and of the lower wall of the section of the lower bearing in the angle sectors cc from 60 to 1200 with the vertices at the centers of the bores for the rolling bearing and with the bisectors of the angles passing on the vertical axis

  of the bore, is conditioned to the following factors.

  The dispersion of the loads on the bearing in the DC angle sector positively influences the work of the bearing and its service life. The contact pressure surface of the bearing rollers on the surface of the hoops increases, which reduces the load on each roller of the bearing. This creates the conditions for use in dynamic load cages, for example, in rolling mills with pilgrim steps, rolling bearings, instead of sliding bearings normally used in these cages. This provides stable rigidity to the cylinder supports of the

  cage and high quality rolling.

  If the angle oc is less than 60, the main force on the outer hoop of the bearing will be transmitted in the sector of this angle a, which means that the surface of the contact pressures on the bearing body of the bearing will decrease, the number of roller bearing bodies receiving the load will decrease, and the contact pressure on the rollers will increase considerably. With heavy loads

  dynamic, this can cause deformation of the bearing hoop.

  If the angle cl is more than 120, the forces are distributed over the outer hoop of the bearing will be in the area close to the horizontal axis of the bearing, which will negatively influence the work of the rollers of the bearing. It will become possible to pinch the rollers in the bearing frets. In addition, the width of the pad increases, the height of the shoulders decreases and their bending becomes possible, this

who is not eligible.

  According to the invention moreover, the thickness of the walls of the bearings on the sections of the corner radii advantageously represents between 1.1 to 2.5 times the thickness of the walls of the bearing on the vertical axis of the bore for the rolling bearing. The bead of the wall of the middle upper section of the upper bearing and of the lower wall of the lower bearing to the values indicated is necessary to create a uniform distribution of the forces on the bearing hoop on the sections of the sector of the angle a ranging from 60 to 120, in the spoke area. This guarantees a uniform load on the rolling element of the bearing, increasing the number of rolling elements participating in the transmission of

the effort on the bearing frets.

  If the thickness of the wall of the bearing on the radii of angle ao is less than 1.1 times the thickness of the wall of the middle upper section of the upper bearing on the vertical axis of the bore, this means that on the bisector of angle a, the local sections of the forces on the upper hoop of the bearing on the radii of angle a will decrease considerably and the maximum force will approach the horizontal axis of the bearing with a going from 100 to 120. This is undesirable, because a

  jamming of the rolling bodies in the bearing hoops becomes possible.

  If the thickness of the bearing wall on the spokes of angle ac is more than 2.5 times the thickness of the wall of the middle upper section on the vertical axis of the bore, it will be necessary to '' increase the width of the shoulders, which is undesirable. The force zone will approach the top of the wall in the zone of the vertical axis of the bore, which will decrease the surface of the dispersion of

  the load on a greater number of bodies of revolution of the bearing.

  According to the invention, the clearance between the surfaces of the bearing and of the extension, and of the bearing and of the support represents from 0.05 to 0.2 times the thickness of the wall of the middle part of the bearing on the vertical axis of

  the bore of the rolling bearing, and damping linings fill the game.

  The play is necessary to allow the shape of the bearing wall to change at the moments of the distribution of the forces on the right 0o and left sections of the outer hoop of the bearing, during the birth of the bending forces on the interior surfaces of the wall of the bearing in the areas of the radii of the angle ax and of the external surface of the wall of the bearing in the area

  the vertical axis of the bearing bore.

  Filling the clearance with a cushioning pad is necessary to reduce the tensile stresses during peak loads and prevent

a load shock on the bearing.

  If the clearance is less than 0.05 times the thickness of the bearing wall on the vertical axis of the bore, it is difficult to obtain attenuation of shock loads, because the lining is thin and has low shock absorbing properties, and increasing the clearance to more than 0.2 times the thickness of the cushion wall is

  undesirable, because a deformation of the outer hoop of the bearing becomes possible.

  The invention will now be described in relation to the accompanying drawings, given by way of nonlimiting examples. In these drawings: - fig. 1 shows the rolling stand on the side of the pins of the rolling rolls; - fig. 2 shows the rolling stand on the rolling side; and - fig. 3 represents the upper bearing with planes of

  load distribution on rolling bearings.

  The device consists of a frame 1 (fig. 1 and 2), of horizontal cylinders 2 placed in upper and lower bearings 3,4 on the radial rolling bearings 5, arranged in the bores 6 formed in the bearings 3, 4. The upper bearing 3 on the side of the trunnions of the cylinders 2 has a shape in "IT", as defined in section by the left and right shoulders 7, 8 whose sides opposite towards each other with respect to the axis vertical of the bore 6, are interconnected at points "a" and "b" (fig. 3) by upper profiles 9 (fig. 2), defining a middle section of the bearing 3 which has a bore for a rolling bearing 5. The upper wall 10 of the middle section of the upper bearing 3 is in a sector of angle a ranging from 60 to 120 whose radii diverge upwards from the center of the axis of the bearing 5 , in different directions towards points "a" and "b" (fig. 3) of a conjugate extension piece 12 with curved profile 9 forming the sides of the

  shoulders 7,8, the bisector of angle a passing through the vertical axis of bore 6.

  The wall 10 of the bearing 3 includes a bead proportional to the distances between the upper curves, symmetrically with respect to the vertical axis of the bore 6

  towards points "a" and "b" of the part conjugated with the shoulders 7, 8.

  The thickness of the wall 10 of the upper bearing 3 and of the lower wall of the lower bearing 4 on the vertical axis of the bore 6 is between 0.05 to

  0.25 times the diameter of the bore 6.

  The shape of the lower pad 4 is the mirror image of the shape of the

upper pad 3.

  Above the pad 3, on the pressure screw 11, is placed an extension 12, and under the lower pad 4 is placed a support 13. The extension is supported on the shoulders 7.8 of the pad 3 by cylindrical hinges 14, forming a clearance 9 between the surface of the extension 12 and the

  surface of the pad 3, having the same shape as this.

  The lower pad 4 rests on the shoulders 7, 8 of the support 13 by means of cylindrical hinges 16, forming a clearance 15 between the surfaces of the

pad 4 and support 13.

  The hinges 14, 16 are freely secured in the bores of the extension 12 by means of tightening bolts 17, simultaneously securing the pads 3, 4 on the extension 12 and the support 13, the pads 3.4 having

  the possibility of tilting in the axial plane during the bending of the cylinders 2.

  The clearance 15 between the surfaces of the bearings 3 4 of the extension 12 and of the support 13 is between 0.05 to 0.2 times the thickness "A" of the wall 10 on the axis

  vertical of bore 6 for bearing 5.

  The games are filled with cushioning pads, for example, in

  alloy of manganese and copper, which have damping properties.

  The thickness of the wall 10 of the bearings 3,4 on the sections of the bearings 5 in the radii of the angle a between 60 to 120 is between 1.1 to 2.5

  times the thickness "A" of the wall 10 on the vertical axis of the bore 6.

  The lower surface 18 of the wall 10 of the pad 3 and the upper surface of the wall 10 of the pad 4 are formed in a trapezoid, the small

  bases are turned towards each other.

  Between the shoulders 7.8 of the lower cushion 4 and the stops 19

  find the hydraulic cylinders 20 for thrusting the bearing.

  The pushing mechanism of the upper cushion 3 is not

shown in fig. 1.

  Fig. 3 shows in diagram 21 the distribution of the load on the bearing according to the closest prior art in diagram 22 the distribution of the load on the bearing of the rolling stand according to the invention for m / A = 2.0 and a = 120, m

  representing the maximum thickness.

  The assembly of the bearing groups of the rolling stand is as follows. The cassette sockets (not shown in the fig.) Are placed on the working cylinders 2, on which the bearings 3,4 are mounted with roller bearings 5 in four rows. Is placed on the surface of the upper pad 3 and on the surface of the support 13 of the linings, for example, of Mn-Cu alloy, having a high damping power, of a thickness between 0.5 to 0.2

  times the thickness "A" of the wall 10 of the upper pad 3.

  The bearing 3 is connected to the extension 12 by tightening bolts 17 after having pre-installed in the bores of the extension 12 and of the support 13 the cylindrical hinges-linings 14, 16. The height of the hinge is the sum of the height of the bore and the value of the clearance 15. Then the nuts of the tightening bolts 17 are tightened with sufficient effort to ensure axial freedom for the bearing 3 and bearing 5 in order to allow the bending of the rolls of the rolling mill 2 and the pressure of the lining against the surface between the bearing 3 and the extension 12. After the installation of the lower bearing 4 on the support 13 with the hinges 16, the pushing mechanism is started. 20 of the pad 4, ensuring a pressure force of the pad 4 through the hinges 16 towards the

support 13.

  The rolling stand works as follows. During the rolling of the blank, for example on a rolling mill with pilgrim's steps, at the front of the grooved rolls 2 the main deformation occurs. The cylinders drive the section of the sleeve placed on the mandrel (not shown in fig.)

  with a posterior lamination of the section of the sleeve.

  When the bush section is driven, an impact occurs from the cone of the groove against the bush. This shock is transmitted through the trunnions of the cylinders 2 on the bearing 5. The load on the upper hoop of the bearing 6 is transmitted through the rollers to the right and left zones of the sector of the angle oc. This results in additional bending of the walls of the pads 3, 4 and an additional distribution of the load on most of the interior surfaces of the exterior hoops. Taking into account the cushioning pads, a small change in the range of play and the deflection of the bearings, the load of

  shock on the bearings 5 is attenuated, which increases the resistance of the bearings 5.

  At the moment of dynamic loading, there is an axial bending of the cylinders 2. The bearings 3,4 tilt on the rolling axis in the direction of the surfaces of the cylindrical linings 14,16, keeping the parallelism with the axes

  of the bearings 5 and the rigidity over the entire length of the bearings 5.

  The proposed improved rolling mill stand can be used in rolling mills with high static and dynamic loads, i.e. in a pilgrim step rolling mill, and will allow the production of rolling products, for example high precision pipes geometric, taking into account the use of radial rolling bearings instead of sliding bearings, and also taking into account

  increasing the rigidity of the cage.

Claims (4)

  1. Cage of the rolling mill according to the invention, preferably of a pilgrim's rolling mill, which comprises a frame (1) receiving horizontal cylinders installed on bearings in upper and lower bearings (4, 5), and pressure screw (11), characterized in that on the side of the cylinder trunnions (2), the upper bearing (3) has a "1" shape, as defined in section by left and right shoulders (7,8 ), in that the pads opposite with respect to the vertical axis (6) have their sides connected to each other by upper curved profiles (9) to the sides of the vertical axis of the bearing, defining a medium section having a bore for a rolling bearing (5), in that the upper wall (10) of the middle section comprises a bead proportional to the distances between the curves of the upper surface of the middle wall of the bearing and the radius of the bore symmetrically at the vertical axis of the bore e towards the joining sections with the shoulders (7,8), in that the shape of the lower pad (4) is the mirror image of the shape of the upper pad (3) and the thickness of the upper wall of the upper bearing and the lower wall of the lower bearing on the vertical axis of the bore is between 0.05 to 0.25 times the diameter of the bore for the bearing, in that above the bearing upper (3) is placed an extension (12) and under the lower pad (4) is placed a support (13) based on the shoulders (7,8) of the corresponding pads, by means of cylindrical hinges (14) arranged in bores of the extension (12), forming a clearance (9) between the surfaces of the extension (12) and the upper surface of the upper pad (3), and in that the lower pad (4) is supported by the shoulders (7 , 8) on the support by means of cylindrical hinges (16), forming a clearance (15) between the surfaces of the neck lower ssinet (4) and of the support (13).   2. Roll stand according to claim 1, characterized in that the upper wall of the middle section of the upper bush (3) and the lower wall of the middle section of the lower bush (4) are in a sector of angle cc included between 60 to 120, with the vertices at the centers of the bores for rolling bearings and with the bisectors passing on the vertical axes of the bores. 3. Roll stand according to claim 1, characterized in that the thickness of the walls of the bearings on the sections of the corner radii a is between 1.1 to 2.5 the thickness of the wall on the axis vertical of the bore for the rolling bearing.   4. Roll stand according to claim 1, characterized in that the clearance between the surfaces of the bearings and the extension (12) and of the support (13) is between 0.05 to 0.2 times the thickness of the wall of the middle part of the bearing on the vertical axis of the bore for the bearing, defining a clearance in which   cushioning pads are arranged.