Equipment and grinding machine for the grinding of external rings of roller bearings

Abstract

Equipment for grinding external rings of roller bearings includes a supporting pin of a bearing to be ground, a stop extending outwardly from the supporting pin for axial positioning of a side of the bearing, a sliding flange on the pin which can be positioned to rest on the other side of the bearing, a clamping nut which can be firmly positioned on a complementary portion of the pin, skids preloaded by springs situated on opposite sides of the bearing, and a guiding element on the opposite side of the stop, which receives a structure carrying a pair of contrast rolls movable to be engaged with the external ring of the bearing creating a radial force thereon, which can be predetermined and regulated by a maneuvering element to eliminate the clearance of the bearing in the radial direction. A machine for housing equipment of the above specified type.

Claims

1. Equipment for grinding external rings of roller bearings, in particular for rolling mills, comprising: a supporting pin (12) of a completely assembled bearing (11) to be subjected to grinding; a stop (13) which extends outwardly from an axis of the supporting pin (12) for axial positioning of a first side of the bearing (11); a sliding flange (15) disposed on the pin (12), which is movable to be positioned to rest on a second side of the bearing (11) inserted on the pin; a clamping nut (16) which is movable to be firmly positioned on a complementary portion of the pin (12); skids (17 and 18) preloaded by springs (21,82) situated on opposite sides of the bearing (11), all of which guarantees axial stability of both an internal ring (14), of rolling elements (19), and of an external ring (20) of the bearing (11), allowing the external ring (20) to rotate on the rolling elements (19); and a guiding element (23) on opposite side of said stop (13) on the pin (12), the guiding element receiving a structure (24) carrying a pair of contrast rolls (25, 26) movable to be engaged with the external ring (20) of the bearing (11) creating a radial force thereon, which can be predetermined and regulated by a maneuvering element (27) to eliminate a clearance of the bearing in a radial direction.

2. The equipment according to claim 1, further comprising gaskets (84,22), situated on opposite sides of the bearing (11) in a position interposed between components (14,19,20) of the bearing (11) and said flanges (13,15) to prevent entry of external fluids during the grinding.

3. The equipment according to claim 1, wherein said stop (13) is annular and extends radially from a side surface of the pin in form of a flanging.

4. The equipment according to claim 1, wherein said maneuvering element comprises a maneuvering screw (27) inserted in said structure (24) carrying the pair of contrast rolls (25,26), the maneuvering screw moving said structure (24) with respect to said pin (12) along a desired grinding direction X.

5. The equipment according to claim 4, wherein a nut (83) floating in a radial direction with respect to the structure (24) and a spring (28), which modulates a preloading of the nut, are associated with said maneuvering screw (27).

6. The equipment according to claim 1, wherein at least one (25) of said contrast rolls (25,26) is rotated by a gear motor (29,30) connected thereto.

7. The equipment according to claim 1, wherein at least one (26) of said contrast rolls (25,26) is idle.

8. A machine for grinding of external rings of roller bearings, in particular for rolling mills, comprising: a base (41) on which a grinding group rests, comprising a wheelhead (45) and a grinding spindle (48) for a grinder (32) on one side facing a pair of supports, or lunettes (70), which house equipment comprising: a supporting pin (12) of a completely assembled bearing (11) to be subjected to grinding; a stop (13) which extends outwardly from an axis of the supporting pin (12) for axial positioning of a first side of the bearing (11); a sliding flange (15) disposed on the pin (12), which is movable to be positioned to rest on a second side of the bearing (11) inserted on the pin; a clamping nut (16) which is movable to be firmly positioned on a complementary portion of the pin (12); skids (17 and 18) preloaded by springs (21,82) situated on opposite sides of the bearing (11), all of which guarantees axial stability of both an internal ring (14), of rolling elements (19), and of an external ring (20) of the bearing (11), allowing the external ring (20) to rotate on the rolling elements (19); and a guiding element (23) on opposite side of said stop (13) on the pin (12), the guiding element receiving a structure (24) carrying a pair of contrast rolls (25, 26) movable to be engaged with the external ring (20) of the bearing (11) creating a radial force thereon, which can be predetermined and regulated by a maneuvering element (27) to eliminate a clearance of the bearing in a radial direction.

9. The machine according to claim 8, wherein said equipment is fixed with respect to said base (41) and said grinding group is movable.

10. The machine according to claim 8, wherein said supports (70), which house said equipment are constrained to a movable bench (75) with respect to said base and said grinding group is fixed with respect to said base.

Description

(1) The structural and functional characteristics of the present invention and its advantages with respect to the known art will appear even more evident from the following description, referring to the enclosed drawings, which, inter alia, show a schematization of an embodiment of equipment produced according to the same invention, and a relative machine. In the drawings:

(2) FIGS. 1 to 5 show some types of known rolling mills in schematic form;

(3) FIG. 6 shows, in schematic form, a design of a back-up roll used in multi-high rolling mills;

(4) FIG. 7 shows a functioning scheme of a bearing assembled on a back-up assembly;

(5) FIG. 8 shows the geometry of a back-up assembly as shown in FIG. 7;

(6) FIGS. 9a and 9b show, in schematic form, a measurement instrument of a back-up ring after grinding;

(7) FIG. 10 shows, in a sectional view, the assembly of a complete bearing on a pin of equipment that can be used on a grinding machine;

(8) FIGS. 11 and 12 show sections in which a free bearing and a bearing assembled on a pin, respectively, can be observed;

(9) FIG. 13 shows a view in which a bearing is assembled on a pin without an internal ring;

(10) FIG. 14 shows, in a sectional view, the assembly of only one external ring of a bearing on a pin of equipment that can be used on a grinding machine;

(11) FIGS. 15a and 15b show two opposite side views of equipment according to the invention to be applied to a grinding machine;

(12) FIGS. 16a, 16b and 16c represent longitudinal sections of the equipment shown in FIGS. 15a and 15b according to the lines XV-XV, XVI-XVI and a detail;

(13) FIG. 17 is a sectional transversal view of the equipment according to the lines XVII-XVII of FIG. 15a;

(14) FIG. 18 is an end view of the equipment according to the arrow M of FIG. 15a;

(15) FIGS. 19a and 19b are perspective views of the equipment of FIGS. 15a and 15b;

(16) FIG. 20 is a further perspective view, but partially cross-sectional and with another angulation for showing other constructional and functional details of the equipment of FIGS. 15a and 15b;

(17) FIG. 21 shows how the equipment of the present invention, such as that illustrated in FIGS. 15a and 15b, is associated with a grinding schematized in a grinding wheel;

(18) FIGS. 22, 23 and 24 show an embodiment of a machine for the grinding of roller bearings which uses the equipment of the previous figures from 15 onwards;

(19) FIGS. 25, 26 and 27 show a further embodiment of a machine for the grinding of roller bearings which also uses the equipment of the previous figures from 15 onwards.

(20) With reference to FIG. 15 onwards and with respect to what is specified above, a non-limiting embodiment of equipment according to the present invention, is illustrated.

(21) This is equipment for the grinding of external rings of roller bearings, in particular for rolling mills.

(22) The figures show how a roller bearing 11 is mounted, fully assembled, on a supporting pin 12. The axial positioning of the roller bearing 11 is guaranteed by a stop 13 which extends outwardly from the supporting pin 12. In particular, in the example shown, the stop is of the annular type 13 and extends radially from the side surface of the pin in the form of a flanging of the supporting pin 12.

(23) A side of an internal ring 14 of the bearing 11 rests in correspondence with said stop 13, which is withheld also in correspondence with the second side, by means of a flange 15 and a clamping nut 16.

(24) In particular, the clamping nut 16 is positioned, for example screwed, on a complementary threaded portion of the pin 12. The flange 13 carries, in the side facing the bearing, a series of recesses with an axis parallel to the axis of the pin 12; a skid 18 is housed in each of the recesses and a spring 82 is applied between the recess and the skid. Likewise, the flange 15 carries a series of similar recesses, in each of which a skid 17 and a spring 21 are housed. The radial position of said recesses on the flanges 13 and 15 is studied so as to ensure that once the assembly of the bearing is complete, the skids 18 and 17 are in contact with the sides of the external ring 20. The function of the flanges 13 and 15 is to guarantee the axial blockage of the internal ring 14, once the nut 16 has been fully tightened. Furthermore, during the tightening, the skids 18 and 17 are pressed against the sides of the external ring 20 and the springs 82 and 21 are suitably preloaded, packing the external ring 20 so that the whole unit guarantees a sufficient axial stability of said ring, at the same time enabling it to rotate on the rolling elements 19. Suitably shaped gaskets 84 and 22 are also envisaged, interposed between elements of the bearing and flanges 13 and 15, which prevent the coolant used during the grinding process from entering the internal parts of the bearing 11.

(25) The pin 12, on the opposite side to where the nut 16 is positioned with respect to the stop 13, carries a guiding element which forms a prismatic seat 23 and acts specifically as a guide for a supporting structure of a pair of contrast rolls 25 and 26. Said structure 24 can slide, supported by the prismatic guiding seat 23, in a radial direction and parallel to the grinding axis X, wherein grinding axis X refers to the direction along which the wheel moves for approaching or moving away from the bearing to be ground (FIG. 21), to allow, after the assembly of the bearing 11, the contrast rolls 25 and 26 to move towards the bearing 11 and exert a desired pressure on the external ring 20 of the same bearing, in the above direction X.

(26) The approaching of the contrast rolls 25 and 26 towards the external ring 20 of the bearing 11 is effected by acting on a manoeuvring element 27. Said screw 27 is engaged in a threaded nut 83 inserted in the structure 24 and, once it has been caused to rotate in a clockwise direction, said screw 27 reacts by resting against the prismatic guide 23 making the axial movement of the screw itself along X impossible. The nut 83 must therefore react, and moves in an axial direction pulling the structure 24 with it and consequently also the rolls 25 and 26. When the two rolls 25 and 26 come into contact with the outer surface of the external ring 20, they push the external ring against the rolling elements 19 of the bearing 11 which, in turn, press against the internal ring 14 which is supported by the pin 12. When the packing of the three elements of the bearing has been effected, the relative movement along X between the structure 24 and the pin, is in fact no longer possible; it is however possible to modulate the load that the rolls 25 and 26 exert on the bearing according to the following description. The nut 83, in which the screw 27 is engaged, is not rigidly constrained to the structure 24 in a radial direction X, but can slide along this direction, as it is axially constrained by a set of springs 28. When the radial packing of the bearing has taken place and therefore the relative movement between the structure 24 and pin 12 is no longer possible, the nut 83 begins to slide in the direction X with respect to its seat 24, generating the compression of the springs 28. The preloading applied to the bearing is given by the product of the rigidity k of the springs times their deflection. The preloading limit is obviously given by the compression of the spring 28; when this is packed, a further action on the screw 27 would cause the blockage of the bearing.

(27) The roll 25 can be rotated by means of an appropriate command, preferably an electric motor 29 and an adapter 30, whereas the roll 26 is assembled idle on the structure 24.

(28) The functioning of the equipment of the present invention, from which its advantages with respect to the known art appear evident, is the following.

(29) In a first phase, the following operating phases are effected, keeping the equipment on a bench.

(30) The screw 27 is rotated in an anticlockwise direction, so that the rolls 25 and 26 are positioned at the maximum distance from the pin 12 itself.

(31) The bearing 11, whatever type it may be (radial with one, two or three roll crowns, for example) is coupled with the pin 12 by means of a hole 31 of its internal ring 14. The tolerances of the diameter of the pin 12 are such as to allow an easy manual assembly. It should be noted that no preliminary operation on the bearing 11 is necessary, such as the dismantling of the internal ring 14 and/or of the rolling elements 19.

(32) The flange 15 is subsequently assembled followed by the axial blockage of the internal ring 14 and containment of the rolling elements 19 and external ring 20 by the stable positioning of the nut 16.

(33) The stable positioning of the bearing 11 on the pin 12 with respect to the equipment of the invention is therefore complete.

(34) At this point, the equipment of the invention is positioned with the bearing 11 integral with it assembled on the grinding machine, schematized in FIG. 21 in a grinding tool, such as a wheel 32.

(35) The pin 12 is assembled on specific supports or supporting lunettes of the grinding equipment 70.

(36) At this point, without having to effect any alignment, the external ring 20 of the bearing 11 can be preloaded by means of the manoeuvring screw 27. When the rolls 25 and 26 are in contact with the external ring 20 of the bearing 11, a preloading can be applied which is such that the ring can still rotate if pulled manually.

(37) In this simple way, the clearance between the external ring 20, rolling elements 19 and internal ring 14 of the bearing 11 are zeroed in the radial grinding direction X, without the application of an axial-symmetrical field of forces, but applying only two radial forces that pass from the centre of each roll 25 and 26 to the centre of the pin 12, resulting in a horizontal force which is calculated as follows with reference to FIG. 21 according to the formula:
Fr=2*F cos
Now, by comparing FIG. 21 with FIG. 7 previously illustrated, it can be immediately observed that, with the equipment of the invention, the bearing 11 has been brought to the loading configuration as in the rolling mill during the functioning of the same. It is in fact sufficient to replace the wheel 32 with the second intermediate roll and the lamination force F with the preloading Fr to have a perfect correspondence between the schemes of FIGS. 7 and 21.

(38) At this point, the grinding of the outer surface of the external ring 20, can be effected using an appropriate grinding program. It should be noted that the external ring 20 of the bearing 11 is conveniently rotated using the gear motor 29, 30 which commands the rotation of the contrast roll 25 in contact with the external ring 20 of the bearing 11.

(39) From an analysis of the embodiment of the equipment according to the invention, the description and its functioning for the positioning during grinding of back-up rings, the following can be observed.

(40) By means of the equipment according to the invention, the bearing, whose outer surface must be subjected to undergo grinding maintenance, is subjected, during said grinding, to a loading scheme almost the same as that to which it is subjected during the processing in the rolling mill. An optimum recovery of the bearing is therefore effected, which does not have any drawback once it has been re-installed on the back-up assembly.

(41) In this way, neither the productivity, on the one hand, nor the quality, on the other, of the rolling mill, has been affected, which re-assembles the bearings subjected to maintenance treatment by grinding.

(42) In the equipment of the present invention, in fact, it can be seen that the same types of loading and deformation to which the bearing is subjected when it is inserted in the rolling mill, are exactly reproduced.

(43) Other constructional solutions of the equipment are also possible, such as those described hereunder for purely illustrative purposes.

(44) In a variant of the equipment, the pin can be supported on grinding centres (rotating tips in the case of a piece-holder head with a tip and drive disc integral with each other, or a fixed tip in the case of decoupled drive disc and tip).

(45) A further variant, the rotation control, can be provided by the piece-holder head of the grinding machine, by suitably modifying the flange 15 which is divided into two parts, one exerting the function of axial blockage of the bearing, and the other applied to the side of the assembled bearing, to allow its contact with the drive disc and entrainment of the external ring.

(46) Furthermore, the rotation control can be supplied by a fixed motor at the grinding bench which, by means of a belt, activates a pulley suitably fixed to the side flange 15 as modified above.

(47) It is also shown how the equipment according to the invention can produce specific machines, also according to the invention.

(48) In a first exemplifying embodiment, a machine is proposed for the grinding of back-up rings with a movable wheel designed for receiving a piece of equipment with a pin such as that previously illustrated.

(49) FIGS. 22, 23 and 24 show various views of a grinding machine on which equipment of the type previously described and according to the present invention, can be positioned.

(50) In this case, a specific grinding machine of back-up rings can be produced, which allows the grinding process of the same to become more rapid and efficient.

(51) A preferred configuration of this machine consists in a base 41 along which a trolley 42 runs in a direction Z. Said trolley 42, in the example, is activated by means of a control actuator 40 composed of an electric motor 43 directly engaged on a worm-screw and slides along suitable guides 44 positioned on the base 41.

(52) A wheelhead 45 slides on said trolley 42, in a direction X perpendicular to the direction Z. The movement of the wheelhead 45 along the direction X can be obtained by means of a suitable control actuator 38 composed of an electric motor 46 directly engaged on a worm-screw 37 and slides along suitable guides 47.

(53) Finally, the wheelhead 45 carries a wheelhead spindle 48 which, without excluding the generic nature of the type of spindle that can be used for the application, is represented as an electro-spindle, i.e. a unit in which the spindle and the motor which activates it are integrated in a single body. This is the rear part of the base.

(54) In the front part of the base 41, there are two openable supports 70, or lunettes, for housing the equipment previously described.

(55) In this case, before beginning the grinding, the bearing must be assembled on the equipment, exactly as described above. When this operation has been completed, the equipment is transported onto the grinding machine and housed on the supports 70. Finally, the preloading positioning of the contrast rolls 25 and 26 is effected on the external ring 20 of the bearing 11 and the grinding of the external ring 20, again as previously indicated.

(56) FIGS. 25, 26 and 27 show various views of a second embodiment of said grinding machine on which equipment of the type previously described and according to the present invention can be positioned.

(57) A preferred configuration of said machine consists of a base 41 and a movable bench on which the equipment of the invention described is positioned; the wheel, on the other hand, is fixed.

(58) This machine is therefore designed for housing the equipment of the invention.

(59) In this case, the two openable supports or lunettes 70 suitable for housing the equipment, instead of being fixed directly on the base 41 of the machine, are constrained to a bench 62, movable in a direction Z1 on the machine by means of a suitable control actuator 63 composed of a motor 64 and a screw 65 and sliding along guides 66.

(60) The equipment according to the invention is therefore used, also in this case.

(61) All the important features forming part of the present invention with respect to both the equipment and grinding machine, can be found in these non-limiting examples.

(62) The objective mentioned in the preamble of the description has therefore been achieved.

(63) The forms of the structure for producing the equipment and machine of the invention, as also the materials and assembly and functioning modes, can obviously differ from those shown for purely illustrative and non-limiting purposes in the drawings.

(64) The protection scope of the present invention is therefore defined by the enclosed claims.