FR2945090A1 - BEARING BEARING COMPRISING AN ENVELOPE FOR MAINTAINING ONE OF THE RINGS - Google Patents

Abstract

The rolling bearing comprises an inner ring 1, an outer ring 2, at least one row of rolling elements 3 arranged between raceways provided on the rings, and at least one casing 5 inside which is disposed at least one of the rings, said ring being made in at least two portions 2a, 2b. The casing 5 comprises at least two distinct portions 20, 21 for holding the portions 2a, 2b of said ring and fastening means 26 of said portions relative to one another.

Description

B09-1428GB-JT / PG EN09020EN Company under Swedish law known as: Aktiebolaget SKF Rolling bearing comprising a casing for holding one of the rings. Invention of: Stéphane Cordier Julien Lapinte Yves-André Liverato Alexandre Manceau Rolling bearing comprising a casing for holding one of the rings.

The present invention relates to rolling bearings, in particular rolling bearings comprising an inner ring and an outer ring with one or more rows of rolling elements held by a cage between raceways provided on the two rings. The rolling elements may be for example balls. This can be for example the case of rolling bearings used in industrial electric motors or in motor vehicle gearboxes. In such applications, the bearings are mainly loaded radially, often with a relatively low load compared to the capacity of the bearings used. The rotational speeds in applications of this type are of the order of 3000 revolutions / minute. US Pat. No. 3,876,266 discloses a rolling bearing comprising an inner ring, an outer ring made in two parts, a casing for holding the two parts of said ring and a row of balls held by a cage. One of the parts of the ring defines, in collaboration with the holding envelope, a space inside which is housed an elastic ring of axial prestressing. To mount such rolling bearings, the procedure is as follows. After inserting the balls in the associated cage and mounted this assembly on the inner ring, the two parts of the outer ring are positioned around the row of balls. This assembly is then mounted and the elastic preload ring in the holding envelope so that it bears against a first radial flange. At this stage of the assembly, the holding envelope comprises an L-shaped section, before the formation of a second radial flange still in the form of an axial extension. Then, the said extension of the envelope is folded to form this second radial flange, which makes it possible, with the first opposite radial flange, to hold the two parts of the outer ring. Given the mounting operations of these rolling bearings, and in particular the folding of the casing so as to form the second radial flange, it is relatively difficult to ensure the existence of the desired axial clearance or contrary to the predefined axial preload . In the latter case, it is then necessary to provide the elastic ring of axial prestressing, which generates an additional cost for the rolling bearing.

The present invention therefore aims to overcome these disadvantages by providing a rolling bearing of simple design, easy to assemble, economical and in which the play or desired axial prestressing can easily be obtained during assembly operations and maintained after assembly of the bearing.

In one embodiment, a rolling bearing comprises an inner ring, an outer ring, at least one row of rolling elements arranged between raceways provided on the rings, and at least one envelope inside which is disposed at least one of the rings, said ring being made in at least two portions. The envelope comprises at least two distinct parts for holding portions of said ring and means for fixing said parts relative to each other. The assembly of two parts or separate parts to obtain the envelope for holding the portions of the ring facilitates assembly operations and to ensure the achievement of the desired operating clearance or axial preload for the rolling bearing. The parts of the envelope preferably each comprise a radial flange for the axial retention of the portions of said ring.

In one embodiment, at least one radial portion of one of the portions of said ring is in contact with one of the flanges, at least one radial portion of the other portion of said ring being in contact with the other flange. One of the parts of the envelope may also include an axial portion in radial contact with the portions of said ring and connected to the flange of said portion. Said ring is in contact by its periphery with the axial portion of the envelope, which makes it possible to ensure its centering. Said portion of the envelope may also comprise a radial flange extending outwardly the axial portion. In one embodiment, one of the parts of the envelope has at least one portion extending beyond the inner ring and / or the outer ring for fixing the bearing on an outer member. This portion may be axial, radial or oblique.

The fixing means may comprise fixing screws. The fastening means may also comprise welds or solders. Alternatively, it is still possible to provide the attachment of the two parts relative to each other by crimping, gluing, riveting, latching, etc.

In one embodiment, at least one of the portions of said ring defines a closed space with the envelope inside which a lubricating product is placed. Each of the portions of said ring can define with the envelope a closed space. Lubricating means for the lubricant, comprising axial holes, at least partly facing one another, are preferably formed in the thickness of a radial portion of each of the two portions of said ring to allow communication two closed spaces. This results in a rolling bearing capable of operating for a long time thanks to effective internal lubrication. The lubricating product may be grease or oil. In the case where the lubricating product is oil, it can advantageously be contained in a porous element mounted inside the closed space.

Specific passage means are preferably provided for the passage of the lubricant between the closed space and the raceways. The passage means may comprise holes or passages made in the thickness of said ring. These passages preferably open into the raceway of said ring. In one embodiment, the ring mounted in the casing has been made by cutting and stamping a sheet metal sheet, said ring comprising an external axial portion in contact with an axial portion and a radial flange of one of the parts of the casing. the envelope, a radial portion, a toroidal portion defining a portion of a raceway and an inner axial portion. The aforementioned closed space is defined by said portions of the ring and by the radial flange of said portion of the envelope. It may be advantageous to provide that the internal walls of the aforementioned closed space comprise an oleophobic coating, so as to promote the exit of the lubricant. The bearing ring defining the closed space containing the lubricant may be the outer ring or the inner ring of the bearing. In the case where said ring is the inner ring of the bearing, it is advantageous that it is also the rotating ring so that the centrifugal force exerted on the lubricant during operation of the bearing promotes the extraction of the lubricant and thus the lubrication of the runways. Alternatively, the two portions of the ring may be of massive type. By solid type part, a part whose shape is obtained by machining with removal of chips (turning, grinding) from tubes, bars, blanks forged and / or rolled. In one embodiment, the two rings of the bearing are of the same structure. Each ring is arranged in an envelope. The present invention will be better understood on studying the detailed description of embodiments taken by way of nonlimiting example and illustrated by the accompanying drawings in which: - Figure 1 is an axial half-section of the rolling bearing according to the invention in a first embodiment; FIG. 2 is an axial half-section of a second embodiment; FIG. 3 is an axial half-section of a third embodiment; FIG. 4 is an axial half-section of a fourth embodiment; FIG. 5 is an axial half-section of a fifth embodiment; and - Figure 6 is an axial half-section of a sixth embodiment. Referring to Figure 1 which illustrates a first embodiment of a rolling bearing according to the invention, it comprises an inner ring 1, an outer ring 2 constituted by two outer portions or half-rings 2a, 2b , a row of rolling elements 3 constituted in the example illustrated by balls and held by a cage 4 between the inner ring 1 and the outer ring 2. The two half-rings 2a, 2b of the outer ring are arranged in a 5. The inner ring 1 is solid and has on its outer cylindrical surface a toroidal groove 6 forming a raceway for the rolling elements 3 whose radius of curvature is slightly greater than the radius of the rolling elements. The inner ring 1 can be manufactured by turning or forming a steel blank, said blank then being ground and possibly lapped at the location of the raceway 6 in order to give the ring 1 its geometric characteristics and its surface state. final.

The cage 4 comprises a plurality of cells 7 provided for housing the rolling elements 3 and their retention with a regular circumferential spacing. The cells 7 are advantageously of spherical shape with a diameter slightly greater than that of the rolling elements 3. The cells 7 are formed in the radial thickness of the cage 4 which comprises a radial portion 8 radially facing the outer ring 2 which is extended radially inwards by a conical portion 9. The conical portion is located radially facing the inner ring 1 and extends axially towards the rolling elements 3. The radial portion 8 and the conical portion 9 define the cells 7 The conical portion 9 forms a guide portion for guiding the cage 4 by the rolling elements 3. In this embodiment, the two portions 2a, 2b of the outer ring 2 are identical and symmetrical with respect to the axial plane of the symmetry of the bearing to reduce manufacturing costs. Alternatively, it is of course possible to provide non-symmetrical portions 2a, 2b. These two external half-rings 2a, 2b can advantageously be manufactured by cutting and stamping a sheet of metal sheet, the parts obtained being then cured by heat treatment. The raceways provided for the rolling elements 3 can be ground and / or ground to give them their geometric characteristics and their final surface state. The two half-rings 2a, 2b being identical in this example, here will be described only one of them, bearing the reference "a", it being understood that the identical elements of the other half-ring 2b bear the reference "b". The half-ring 2a of the outer ring 2 comprises an outer axial portion 11a, a radial portion 12a, a toroidal portion 13a and an inner axial portion 14a. The radial portion 12a is connected to the axial portion 1 the outer and the toroidal portion 13a. The toroidal portion 13a defines a portion of a raceway 15a for the rolling elements 3. The radius of curvature of the race 15a is slightly greater than the radius of the rolling elements 3. The toroidal portion 13a also connects to the axial portion 14a internal. The two external half-rings 2a, 2b are arranged with the radial faces 16a, 16b of the radial portions 12a, 12b in axial contact with one another, substantially in the axial plane of symmetry of the rolling bearing and the rolling elements. 3. The envelope 5 comprises two annular portions 20, 21 enclosing the two outer half-rings 2a, 2b so as to keep them firmly axially against each other. The parts 20, 21 of the envelope 5 can advantageously be made economically from the same side sheet by cutting and stamping.

The portion 20 comprises an annular radial flange 22 extending to the immediate vicinity of the outer cylindrical surface of the inner ring 1. An inner edge 22a of the flange 22 leaves a radial clearance with said cylindrical surface la. The outer radial face 22b of the flange 22 is situated in a radial plane containing the radial face 1b of the inner ring 1. The portion 20 also comprises an annular axial portion 23 extending axially an outer edge of the flange 22 and extending axially in the direction from the portion 21 of the envelope 5 to its immediate vicinity. The portion 20 further comprises an annular radial flange or collar 24 extending radially outwardly of the axial portion 23 axially on the side opposite to the flange 22. The flange 24 extending radially beyond the annular portion 23 and leaves a slight axial clearance with the part 21 of the envelope 5.

The portion 21 of the envelope is constituted by an annular radial flange 25 extending to the immediate vicinity of the outer cylindrical surface of the inner ring 1 so that an inner edge 25a leaves a radial clearance with said surface . The flange 25 extends radially beyond the axial portion 23 of the portion 20 and the collar 24. The outer radial face 25b of the flange 25 is located in a radial plane containing the radial face 1c of the inner ring. In order to allow relative attachment of the parts 20, 21 of the casing, fixing screws 26 are provided to secure the flange 25 of the portion 21 on the radial flange 24 of the portion 20. In this respect, holes 27 are provided. conical are formed in the thickness of the flange 25 to allow the passage of screws 26 fixing. The holes 27 are preferably distributed evenly over the flange 25 in the circumferential direction. The flange 24 also comprises threaded portions 28 formed in its thickness and coming opposite the holes 27 of the flange 25 for the passage of the screws 26 and the relative fixing of the parts 20, 21 of the envelope 5. The half-rings 2a, 2b are centered in the axial portion 23 of the portion 20 of the casing 5 by contact of the axial portions 11a, 11b with the bore of said axial portion. The outer radial faces 17a, 17b which form the annular edges of the axial portions 11a, 11b are respectively in contact with the radial flanges 22, 25 of the parts 20, 21 of the casing 5, which ensures the axial clamping of the two half-rings 2a, 2b one against the other. The outer radial faces 18a, 18b forming the annular edges of the axial portions 14a, 14b internal are also in contact with the radial flanges 22, 25. Each of the half-rings 2a, 2b defines, with the envelope 5, a closed space 31a , 31b annular lubricant reservoir, the lubricant contained in these spaces 31a, 31b not shown in FIG. More specifically, the closed space 31a is defined by the axial portion 1 the outer, the radial portion 12a, the toroidal portion 13a, and the inner axial portion 14a, and with respect to these portions, the flange The lubricant used may be grease or oil. Means of passage may be provided for the passage of the lubricant from the closed spaces 31a, 31b acting as lubricant reservoirs to the races 6 and 15a, 15b. These passage means comprise a plurality of communication holes 32a, 32b passing through the thickness of the outer half-rings 2a, 2b at the junction zone between the axial portion 14a, 14b internal and the toroidal portion 13a, 13b . This arrangement of the holes 32a, 32b allows the lubricating product to flow directly onto the rolling elements 3 at the end of the races 15a, 15b. I1 is also provided a plurality of axial holes 33a, 33b through in the thickness of the radial portion 12a, 12b. The axial holes 33a, 33b formed respectively on the two half-rings 2a, 2b are at least partly opposite each other. This arrangement which can be maintained by appropriate positioning during assembly or by unrepresented angular indexing means provided on the two half-rings 2a, 2b allows communication of the two closed spaces 31a, 31b. This arrangement also allows when there is a slight axial clearance between the half-rings 2a, 2b to allow, from the holes 33a and 33b, a flow of the lubricant which flows directly on the rolling elements at the races 15a , 15b. Preferably, the internal surfaces of the lubricant reservoir spaces 31a, 31b have an oleophobic coating which has the effect of preventing the lubricant from adhering to the inner walls and thereby promoting its transfer. The various elements of the rolling bearing are mounted as follows. After inserting the rolling elements 3 into the cells 7 of the cage 4 and mounted on the inner ring 1, the two half-rings 2a, 2b are positioned around the row of rolling elements 3. The lubricant is available in the space 31a which constitutes a first lubricant reservoir between the half-ring 2a and the inner ring 1. The lubricant is also available in the second space 31b and in the volume remaining between the inner ring 1 and the outer ring 2. The part 20 of the casing is then mounted over the two half-rings 2a, 2b so that the two half-rings are in contact by their periphery with the axial portion 23 to ensure the centering of the outer ring 2. The outer radial faces 17a, 18a of the axial portions Ila, 14a are in contact against the inner radial face 22c of the flange 22 of the portion 20. After this establishment of the two half-rings 2a, 2b in the part 20 of the envelope 5, the flask 25 const the portion 21 of the casing is mounted to axially hold the half-rings 2a, 2b. In this respect, the inner radial face 25c of the flange 25 abuts against the outer radial faces 17b, 18b of the axial portions 11b, 14b. The axial portions 11a, 14a of the half-ring 2a bear against the flange 22 of the portion 20, the axial portions llb, 14b of the half-ring 2b bear against the flange 25 of the portion 21, the radial portions 12a, 12b of said rings being axially in contact with each other. The parts 20, 21 make it possible to firmly hold the two half-rings 2a, 2b firmly against one another. Then, the relative position of the two parts 20, 21 of the envelope 5 is fixed by screwing the screws 26. In this embodiment, the inner radial faces 16a, 16b of the radial portions 12a, 12b are in contact with one another. the other. This contact between the radial portions 12a, 12b makes it possible to obtain the rolling bearing with an internal clearance. Of course, in order to ensure prestressing of the raceways 15a, 15b and 6 on the rolling elements 3 so that the rolling bearing operates with zero internal clearance, it is possible to provide that the inner radial faces 16a, 16b radial portions 12a, 12b are not in contact. During the assembly of the rolling bearing, the predetermined relative axial disposition of the half-rings 2a, 2b is obtained easily by bringing the flange 25 towards the flange 24 to the desired position. From the relative axial position of the flange 25 and the flange 24, it can effectively be easily controlled if the internal clearance or, on the contrary, the desired axial prestress is reached inside the rolling bearing. The embodiment of the envelope 5 in two parts 20, 21 thus makes it possible to easily check that the play or that the prestressing provided for the rolling is achieved before fixing the parts 20, 21 relative to each other. Moreover, the fixing of the two parts 20, 21 relative to one another makes it possible to ensure that this characteristic of the rolling bearing will be retained after its assembly and its installation in the mechanical assembly for which it is intended after assembly. . Once the assembly of the rolling bearing is completed, the part or parts 20, 21 of the envelope 5 can be used to mount it on an external element. In the example illustrated in the figure, the rolling bearing is fitted inside a bore 35a of an outer member 35, the flange 24 of the portion 20 of the casing 5 bearing against a radial face outer 35b of said element. An annular spacer 36 is provided between the outer radial face 35b of the element 35 and the inner radial face 25c of the flange 25 of the portion 21 of the envelope. The spacer 36 is also in abutment against the outer edge of the flange 24 of the portion 20. To attach the rolling bearing on the outer member 35, fixing screws 37 are provided. In this respect, conical holes 38 are formed in the thickness of the flange 25 to allow the passage of the fixing screws 37. The holes 38 are preferably distributed evenly over the flange 25 in the circumferential direction. The holes 27 are arranged radially between the holes 27 and the outer edge of the flange 25. The spacer 36 also comprises threaded portions 39 formed in its thickness and facing the holes 38 of the flange 25 for the passage of the screws 38 and the fixing the rolling bearing on the outer element 35. Thus, the portion of the flange 25 extending radially beyond the outer ring 2 allows not only the attachment of the two parts 20, 21 but also the fixing of the rolling bearing. as a whole on the outer element 35. In this embodiment, the portion for fixing the rolling bearing on the outer element 35 extends radially beyond the outer ring 2 of the collar 24 of the part 20 of the envelope. It is easily understood that the flange 25 of the portion 21 of the casing may comprise alternately or additionally one or axial or oblique portions extending axially and / or radially beyond the outer ring 2 to allow the attachment of the bearing to bearing on other elements or the fixing of external means on the rolling bearing. For this purpose, it is also possible to provide radial, axial, oblique portions extending radially and / or axially beyond the inner ring 1. Such portions could also be provided on the part 20 of the envelope 5 .

In the embodiment illustrated in Figure 1, the outer ring 2 is constituted by the two half-rings 2a, 2b and the inner ring 1 is of the massive type. In an alternative embodiment, it could be possible to provide the massive outer ring while the inner ring would be constituted by two half-rings made by stamping a sheet of thin sheet similarly to the half-rings 2a, 2b mode embodiment of Figure 1. These two half-rings would be mounted inside a casing made in two parts and fixed relative to each other. In other words, this arrangement would be identical to that of the embodiment illustrated in FIG. 1, the elements however being reversed. In this case, it would be advantageous if the inner ring constituted by the two half-rings is in operation the rotating part of the rolling bearing. Indeed, in this case, during the rotation of the rolling bearing, the lubricant contained in the two spaces of the half-rings acting as a lubricant reservoir would be subjected to centrifugal force and tend to diffuse through the passages in the rings towards the bearing races of the bearing.

The embodiment of Figure 2 in which the identical elements bear the same references differs only in that the half-rings 2a, 2b are massive. In this embodiment, therefore, it is not provided at these lubricant reservoir rings. In another variant, it could also be possible to provide only one of these half-rings 2a, 2b massive, the other ring having a lubricant reservoir as shown in the embodiment of Figure 1. The mode embodiment shown in Figure 3, in which the identical elements bear the same references, differs from the embodiment of Figure 1 in that the two rings 1, 2 of the bearing are of the same structure. In other words, the inner ring 1 is symmetrical with respect to the outer ring 2 by considering a median axial plane of the rolling bearing passing through the center of the rolling elements 3. The inner ring 1 therefore comprises two half-rings 10a, 10b of identical design to that of the half-rings of the outer ring 2. The half-rings 10a, 10b are clamped in a casing 40 made in one piece, ie monobloc. The casing 40, advantageously made of stamped metal sheet, comprises two radial flanges 40a, 40b and an axial portion 40c connecting to the two radial flanges so as to grip the two half-rings 10a, 10b and hold them firmly together. against each other. The respective radial flanges 22, 40a and 25, 40b face one another with a radial gap. The inner and outer axial portions of the half-ring 10b abut against the inner radial face of the flange 40b, the inner and outer axial portions of the half-ring 10a bearing against the inner radial face of the flange 40a, which ensures the axial clamping of the two half-rings against each other. The half-rings 10a, 10b are centered in the axial portion 40c of the casing 40 by contact of the external axial portions with the outer surface of said axial portion 40 of the casing. In this embodiment, the rolling bearing therefore comprises four closed spaces serving as a lubricant reservoir, namely the spaces defined in each of the parts 2a, 2b of the outer ring and the spaces defined in each of the parts 10a, 10b of the inner ring. In this embodiment, there are further the lubricant passages on the half-rings 10a, 10b of the inner ring provided on the half-rings 10a, 10b of the outer ring. The embodiment of FIG. 4 in which the identical elements bear the same references differs from the first embodiment only in that the assembly between the rolling bearing and the outer element 35 is effected by one or more cords of welding 42 provided between the radial face 35b of the outer member 35 and the spacer 36. Alternatively, it may also be possible to provide the assembly of the rolling bearing with the outer member 35 by brazing, crimping, bonding, riveting , latching or by any other appropriate means. The embodiment illustrated in FIG. 5 in which the identical elements bear the same reference differs from the first embodiment in that the flange 25 of the portion 21 bears axially against the flange 24 of the portion 20 and in that fixing screws 44 are used to perform both the assembly of said parts 20, 21 of the casing of the rolling bearing and the fixing of the bearing on the outer element 34. Conical holes 46 are formed in the thickness. flange 25 to allow the passage of screws 44. Flange 24 also has threaded portions 48 formed in its thickness opposite holes 46.

The embodiment illustrated in FIG. 6 on which the identical elements bear the same references differs from the embodiment previously described in that the assembly of the parts 20, 21 of the casing of the bearing is carried out via one or more cords of welding 50 provided between the outer edge of the flange 25 of the portion 21 and the radial flange 24 of the portion 20. The attachment of the rolling bearing on the outer member 34 is also obtained by one or weld seams 52. Alternatively, it may be possible to provide the attachment of the parts 20, 21 relative to each other by crimping, gluing, riveting, latching or any other suitable means. The features and features mentioned for each of the embodiments could be applied without substantial modification to the other embodiments. On the other hand, although the present invention has been illustrated from single-row ball bearings, it will be understood that the invention can be applied without major modifications to bearings using rolling elements which are not balls. / or several rows of rolling elements.

Claims (10)

REVENDICATIONS1. Roller bearing comprising an inner ring (1), an outer ring (2), at least one row of rolling elements (3) arranged between raceways provided on the rings, and at least one casing (5) at inside which at least one of the rings is arranged, said ring being made of at least two portions (2a, 2b), characterized in that the envelope (5) comprises at least two distinct parts (20, 21). for holding the portions (2a, 2b) of said ring and fastening means (26; 44; 50) of said portions relative to one another. 2. Rolling bearing according to claim 1, wherein the parts (20, 21) of the casing each comprise a radial flange (22, 25) for the axial retention of the portions (2a, 2b) of said ring. 3. Rolling bearing according to claim 2, wherein at least one radial portion (11a) of one of the portions (2a) of said ring is in contact with one of the flanges (22), at least one radial portion. (11b) the other portion (2b) of said ring being in contact with the other flange (25). 4. rolling bearing according to claims 2 or 3, wherein one of the parts (20, 21) of the casing comprises an axial portion (23) in radial contact with the portions (2a, 2b) of said ring and connecting to the flange (22) of said part. 5. rolling bearing according to claim 4, wherein said portion of the casing comprises a radial flange (24) extending outwardly the axial portion (23). Roller bearing according to any one of the preceding claims, wherein at least one of the parts (20, 21) of the envelope comprises at least one portion extending beyond the inner ring (1). and / or the outer ring (2) for fixing the bearing on an outer element. The rolling bearing as claimed in any one of the preceding claims, wherein the securing means comprise fixing screws (26; 8. Rolling bearing according to any one of the preceding claims, wherein the fixing means comprise welds (50) or solders. 9. rolling bearing according to any one of the preceding claims, wherein at least one of the portions (2a, 2b) of said ring defines a closed space (31a, 31b) with the envelope inside which is disposed a lubricant product. 10. Rolling bearing according to any one of the preceding claims, wherein the inner ring (1) and the outer ring (2) are of the same structure, each of the rings being disposed in a casing (5, 40).