Multifunctional unit for rolling bearings

Abstract: Multifunctional unit (1) for rolling bearings comprising a first (6) and a second (7) substantially rigid screen, respectively coupled to an outer rotary ring (3) and to a fixed internal ring (4) of the bearing (2), and a rubber seal (8) fixed to the first screen (6) and having a first double contact lip (9) extending to come into contact with the second screen (7) for the dynamic protection of the bearing (2); an assembling device, constituted by a first (25) and a second (21) element respectively fixed to the seal (8) and to the second screen (7), being provided for assembling said screens (6, 7) to each other preventing any mutual decoupling; the two radial elements (21,25) being axially and radially staggered in relation to each other.

Description: The present invention concerns a multifunctional unit for rolling bearings. Normally, the multifunctional units for well-known types of rolling bearings comprise a first substantially rigid screen coupled to an outer rotary ring of the bearing, a second substantially rigid screen coupled to a fixed inner ring of the bearing, and a rubber lip fixed to the first screen and extending to come into contact with the second screen for the dynamic protection of the bearing. It has been found that, once installed on the respective bearings, the multifunctional units of the type described above, while having demonstrated that they possess a high level of efficiency when in use, have presented some disadvantages which are essentially due to the instability between the two screens, which, in the more serious cases, has involved the separation of the two screens from each other. The scope of the present invention is to realise a multifunctional unit for rolling bearings, which will permit a higher level of reliability as regards its assembly during transport, without, despite this fact, having any other than a minimal effect on the production costs of said multifunctional unit for rolling bearings. According to the present invention a multifunctional unit for rolling bearings is proposed, as disclosed in US-A-5 863 124 and further characterised in that a second radial element extends from the second screen towards the first screen in a position which is axially and radially staggered regarding the first radial element. The invention will be now described with reference to the attached drawings, showing a not limiting embodiment of the invention, in which: figure 1 illustrates in axial section, with parts removed for clarity, one preferred embodiment of the multifunctional unit of the present invention; and figure 2 illustrates, on an enlarged scale, a detail of figure 1. With reference to figures 1 and 2, the number 1 indicates, in its entirety, a multifunctional unit for rolling bearings 2, in particular, bearings for conducted wheels comprising an outer rotary ring 3, a fixed internal ring 4, and a flange 5 fixed to the outer ring and transversal to a rotational axis A of the bearing 2. Unit 1 comprises two substantially rigid screens 6 and 7, respectively coupled to the outer ring 3 and to the internal ring 4, and a rubber seal 8 which is fixed to the screen 6 and provided with a double contact lip 9 extending to contact the screen 7 for the dynamic protection of the bearing. Unit 1 comprises, moreover, an assembling device 10 which is interposed between the two screens 6 and 7 in order to assemble between them the screens 6 and 7 and to prevent their mutual decoupling both during transport and during the assembly of the unit 1 to the bearing 2. The screen 6 comprises a cylindrical wall 11 fixed on a cylindrical, external surface 12 of the outer ring 3, and an annular wall 13 fixed to said wall 11, and arranged to strike against a front, annular surface 14 of the ring 3. Wall 11 and wall 12 are orthogonally arranged in relation one to the other, and while the wall 11 allows a simplification of the working of the bearing 2 with respect to the cases in which such wall 11 is inserted to the inside of ring 3, wall 12 allows, instead, the increased simplification of both the driving of the unit 1 on the bearing 2, and the control of said driving. The screen 6 further comprises a shaped wall 15, which axially extends towards the inside of the bearing 2 from the wall 13, and is provided with a free, annular attachment 16, which is transversal to the axis A and supports the lip 9. The screen 7 comprises a cylindrical wall 17 fixed on an inner surface 18 of the internal ring 4, and an annular wall 19, which is fixed to said wall 17, and is arranged substantially coplanar to the wall 13. Screen 7 comprises, moreover, a further cylindrical wall 20, which axially extends towards the inside of the bearing 2 from the wall 19, and is provided with a free edge 21 which is radially folded towards the outside in order to face the seal 8. In particular, the edge 21 is radially delimited towards the outside by a cylindrical surface 22, which is coaxial to the axis A, has a radius ρ 1 of determined length, and is faced (pointed out) directly towards the seal 8. Seal 8 completely covers both the surfaces of the wall 15 and the part of the wall 13 which extends beyond the surface 14, and is further provided with a lip 9 which is arranged to form a sliding contact with the wall 17 and the wall 19 of the screen 7; seal 8 provides a further rubber lip 23 which axially extends towards the inside from the wall 13 to come into contact with the surface 14. In particular, the surface 14, on the inner part of the ring 3, is provided with a conical bevel 24 against which lip 23 leans directly in order to render the screen 6 statically hermetic; however, according to a further embodiment, which is not illustrated, the lip 23 can also be arranged directly contact with the part of the surface 14 transversal to the axis A. Seal 8 further comprises an annular, shaped edge 25, which directly faces the wall 20, and is provided with an inner radius ρ 2 which is shorter than the radius ρ 1 of the edge 21, and defines the assembling device 10 together with the edge 21. In particular, because of the radial interference of the edges 21 and 25 due to the different dimensions of the respective radius ρ 1 and ρ 2 , the assembly of the screens 6 and 7 takes place by axially forcing the edge 21 against the edge 25, and arranging, which said assembly is complete, said edge 21 in a position which is axially staggered towards the inside of the bearing 2 in relation to the edge 25. Depending on the requirements, the unit 1 can comprise, as in the embodiment presently described, an encoder 26, which is mounted frontally and fixedly to the annular wall 13 of the screen 6, and is defined by an annular element with substantially rectangular cross-sectional section radially delimited towards the outside by a cylindrical surface 27 of a diameter which is inferior to a diameter of the wall 11, and is radially delimited towards the inside by a further cylindrical surface 28 of a diameter which is substantially inferior to a diameter of the wall 15. The difference in diameter between the surface 27 and the wall 11 allows a simple assembly of the unit 1 using standard equipment, while the space left due to the different dimensions between the surface 28 and the wall 15 is overwhelmed by a connecting portion 29 of the seal 8. Portion 29 axially extends towards the outside of bearing 2, at least by the edge 25, and is radially limited towards the inside by a conical surface 30 which is oriented with a vertex to the inside of the bearing 2. The tapering of the surface 30 determines a centrifugal effect towards the outside of the bearing 2 so as to further increase the dynamic protection of the bearing 2. In the embodiment in which the encoder 26 is not mounted on the wall 13, the assembly operations of the unit 1 on the bearing 2 will be further simplified, having all the surface 14 available in order to exercise against it whichever type of axial force. From the above, it is obvious that the adoption of the present unit 1 provides important advantages both in terms of ease and reliability of assembly, and in terms of stability during transport. It is intended that the invention is not limited to the embodiments herein described and illustrated, which are to be considered as examples of the multifunctional unit, which, instead, is susceptible to further modifications to shape and disposition of parts, constructive details and details of assembly.

Claims: Multifunctional unit (1) for rolling bearings comprising a first substantially rigid screen (6) coupled to an outer rotary ring (3) of the bearing (2), a second substantially rigid screen (7) coupled to a fixed inner ring (4) of the bearing (2), and a rubber seal (8) fixed to the first screen (6) and having a first double contact lip (9) extending to come into contact with the second screen (7) for the dynamic protection of the bearing (2); the unit (1) further comprising assembling means (10), interposed between said two screens (6, 7), to assemble between them said screens (6, 7) preventing any mutual decoupling, and comprising, in turn, a first radial element (25) extending from the first screen (6) towards the second screen (7); characterised in that a second radial element (21) extends from the second screen (7) towards the first screen (6) in a position which is axially and radially staggered regarding the first radial element (25). Unit according to claim 1, characterised by the fact that the first and the second radial elements (21, 25) form part, respectively, of said rubber seal (8) and of said second screen (7), and are defined by a rubber shaped edge which radially extends towards the inside from the seal (8), and, respectively, by an end, free edge of the second screen (7), which is radially folded towards the outside. Unit according to claim 1, characterised by the fact that the first screen (6) comprises a cylindrical wall (11) which is fixed on a cylindrical, external surface (12) of said outer ring (3), and an annular wall (13) which is fixed to said cylindrical wall (11), and arranged against a front, annular surface (14) of said outer ring (3). Unit according to claim 3, characterised by the fact that the seal (8) comprises a second rubber lip (23) axially extending towards the inside from the annular wall of the first screen (6) to substantially come into contact with the frontal surface (14) of the outer ring (3). Unit according to claim 3, characterised by the fact that it comprises a encoder (26) mounted in front of the annular wall (13) of the first screen (6); the seal (8) comprising a connecting portion (29) axially extending towards the outside at least from the first radial element (25), and radially limited towards the inside by a conical surface (30) oriented with a vertex to the inside of the bearing (2).

Inventors: GIAI BRUNO, VIGNOTTO ANGELO, GIAI, BRUNO, VIGNOTTO, ANGELO
Applicants: SKF IND SPA, SKF INDUSTRIE S.P.A.
Application year: 2001
Main classification: F16J15
IPC codes: F16C19, F16J15, F16C33