Cage for rolling bearing and associated rolling bearing unit

Abstract

The rolling bearing unit (6) comprises a rolling bearing (3) and an annular cage (1) formed by two half-cages (10) connected together by pins (16) and holes (18) formed alternately in rows on each half-cage and rigid blocks (21) alternating with recesses (22), the pins (16) of the half-cage being snap-coupled with the holes (18) of the opposite half-cage, and the rigid blocks (21) being snap-coupled with the recesses (22) of the opposite half-cage. A rigid block (21) of the half-cage is coupled with a recess (22) of the opposite half-cage (10), the protruding rigid block (21) supporting a protruding pin (16), a hole (18) being formed in the rear of the recess (22) such that the half-cage is connected by a first coupling (14) and a second coupling (15) in series designed to absorb tangential and axial stresses, respectively; the half-cage is provided with a radial annular ridge (34) acting as a shield.

Description

Technical Field

[0001] The invention relates to a cage for a rolling bearing and a related rolling bearing unit comprising the cage. Background Art

[0002] A rolling bearing is known from DE1914884U, which comprises an outer ring, an inner ring and a plurality of rolling bodies (balls) between the outer ring and the inner ring so that they can rotate relative to each other with low friction. The rolling bodies are held in the correct position by a cage, which comprises:

[0003] a plurality of pockets or seats, each defined by a respective spherical surface having a centre lying in a radial median plane coinciding, in use, with a corresponding radial median plane of the bearing,

[0004] - two half-cages, substantially symmetrical about the midplane and connected to each other, each half-cage having an annular body and a plurality of at least partially hemispherical cavities axially facing the hemispherical cavities of the opposing half-cage to define a cell with said hemispherical cavities, and

[0005] - A connecting member, associated with a half-cage for connecting the two half-cages together.

[0006] -For each half-cage, two substantially concentric and circumferentially continuous radial reliefs extend from each annular body in radially opposite directions, a first relief extending radially outwardly to sealingly engage a groove formed in an outer ring of the bearing, and a second relief extending radially inwardly to sealingly engage a groove formed in an inner ring of the bearing, the inner ring being divided into two half rings joined together.

[0007] A cage for rolling bearings made of two cage halves, which are coupled together to form a seat for the balls of the rolling bearing, is known from JP2007040383 A. The seat is formed by a simple circular hole, and the associated connecting part is a mating snap-on coupling element in the form of a dovetail joint or a snap-on coupling pin in a corresponding cylindrical seat.

[0008] Both solutions described have the disadvantage that the cage formed by coupling two cage halves together may not be rigid enough to prevent elastic deformation of the cage in use caused by variations in the rotational speed typically applied to the rolling bearing in use.

[0009] In DE1914884U, due to the acceleration or deceleration of the bearing, this causes the radial projections to move towards or away from the corresponding grooves. If the projections are designed to form a labyrinth seal, they may contact the grooves, thereby causing undesirable friction, associated energy consumption and undesirable heating, or move too far away from the grooves, causing seal failure.

[0010] Similarly, if the protrusion is designed to form a contact seal in the groove, an increase or loss of interference may have the same negative consequences.

[0011] In JP2007040383A where no sealing protrusions are provided, undesirable elastic dimensional changes of the cage may still render the retaining and guiding action exerted by the cage on the balls (or other rolling elements) of the bearing less effective or ineffective.

[0012] Finally, in the above-mentioned known rolling bearings, a large part of the grease remains "stuck" to the shields and therefore does not contribute to the lubrication of the bearing. Summary of the invention

[0013] The present invention aims to overcome the shortcomings of the prior art, in particular to provide a cage which enables the rolling elements to be always kept in the correct position, thereby eliminating possible noise during use, and at the same time is able to create a seal against external contaminants to protect the rolling elements, and to create a seal against the grease contained between the inner ring and the outer ring in the rolling bearing, all of which is intended to reduce or eliminate the friction or at least the risk of excessive friction between the cage and the rolling bearing.

[0014] Another object of the present invention is to optimize the quantity and location of grease inside the bearing, not only to prevent grease leakage (i.e., leakage of a portion, albeit a small portion, of the lubricant from the bearing), but also to reduce grease losses through "splashing", in particular to use all the grease to lubricate the raceways, thereby potentially reducing the amount of grease required while maintaining constant lubrication over the life of the bearing.

[0015] A final object of the present invention is to provide a rolling bearing unit comprising such a cage which is designed to provide a good seal with low friction between the cage and the rings of the rolling bearing.

[0016] The present invention therefore provides a cage for retaining rolling elements in a rolling bearing and an associated rolling bearing unit as defined in the appended claims.

[0017] In particular, the invention is based on increasing the rigidity of the cage obtained by coupling two half-cages without increasing the size and weight of the cage, which would adversely affect the number of rolling elements that can be inserted in the cage and / or the amount of grease available for the rolling elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Other features and advantages of the present invention are more clearly set out in the following description of non-limiting embodiments of the invention provided with reference to the figures in the accompanying drawings, in which:

[0019] - Figure 1 is a schematic perspective three-quarter side view, partly cut away, of a rolling bearing unit according to the invention, which, in the non-limiting example shown, comprises a rolling bearing with a single row of rolling elements, shown in the non-limiting illustration as balls, and a cage for retaining the rolling elements according to a first embodiment of the invention,

[0020] - Figure 2 yes Figure 1 An enlarged schematic circumferential cross-sectional view of a detail in FIG.

[0021] - Figure 3 is based on Figure 1 A slightly enlarged schematic radial cross-sectional view of a bearing unit and an associated cage for rolling elements according to a first embodiment of the invention and possible variants thereof (shown only with hatching for the sake of simplicity and greater clarity),

[0022] - Figure 4 Belongs to Figure 1 and 2 Schematic enlarged perspective view of a circumferential section of an axially inner annular front face of an annular half cage of a cage for retaining rolling elements, the circumferential section being rotated 90° for the sake of clarity to show the axially inner annular front face of the half cage at the top of the figure, the annular front face facing in use Figure 1 Rolling elements of rolling bearings;

[0023] - Figure 5 and Figure 6 Is used to maintain Figure 1 2. A schematic perspective view of two components of a cage for rolling elements of a bearing in FIG. 1, wherein the cage comprises two identical half cages which are positively coupled together in the axial direction to form a cage having a plurality of identical half cages. Figure 1 and Figure 2 The cage in Figure 5 The half cage is shown with its front side facing the Figure 6 The same front side of the half cage is shown in the opposite direction, and

[0024] - Figure 7 yes Figures 1 to 3 Axial exploded perspective view of the rolling bearing unit. DETAILED DESCRIPTION

[0025] exist Figures 1 to 7 , reference numeral 1 indicates as a whole a cage for retaining rolling elements 2 in a rolling bearing 3. The rolling bearing 3 has an outer ring 4, an inner ring 5, and a plurality of rolling elements 2 interposed between the outer ring 4 and the inner ring 5 so that they can rotate relative to each other with low friction, and forms a rolling bearing unit 6 with the cage 1 interposed between the outer ring 4 and the inner ring 5.

[0026] The retaining cage 1 is therefore designed to be interposed between the corresponding inner ring 5 and outer ring 4 of the rolling bearing 3 when in use, so as to retain the rolling elements 2 in the correct position between the rings 4 and 5 in a known manner, wherein there is a desired pitch between the rolling elements 2, in the non-limiting example shown, the rolling elements 2 are balls.

[0027] The annular cage 1 has an axis of symmetry A which coincides with the axis of symmetry of the rolling bearing 3 in use and is also the axis of symmetry of the rolling bearing unit 6. The axis A is also the axis of relative rotation between the rings 4 and 5.

[0028] The cage 1 comprises a plurality of radial through-seats or pockets 7 arranged in a row, each radial through-seat or pocket 7 being designed to seat a corresponding rolling element 2 .

[0029] In the preferred embodiment shown in which the rolling elements 2 are balls, each of the radial through seats or cells 7 is formed by a corresponding spherical surface 8 ( Figure 1 and Figure 2 ) is defined, the spherical surface 8 has its center located in the radial midplane P of the cage 1, the radial midplane P coinciding with the corresponding radial midplane of the rolling bearing 3 when in use. Figure 2 and Figure 3 The geometric outline of the median plane P is schematically shown in FIG.

[0030] According to one aspect of the invention, the annular retainer 1 comprises two axially opposed annular half retainers 10, which are substantially symmetrical about a midplane P and rigidly connected together (as described in detail below) so as to form a retainer 1 once coupled together, and the retainer 1 acts as if it were substantially formed as a single component.

[0031] The two cage halves 10 are identical and are therefore indicated by the same reference numerals, are made by molding a suitable synthetic plastic material, such as polyamide, and have the same axis of symmetry A, along which they are frontally joined to form the cage 1 .

[0032] Each half cage 10 has an annular body 11 with axis A as axis of symmetry and a plurality of cavities 12 which, in the preferred embodiment shown, are at least partially hemispherical. The cavities 12 are in fact at least partially or completely defined by a corresponding portion of the spherical surface 8 of each cell or seat 7.

[0033] Once the half cages 10 are coupled in the axial direction, the at least partially hemispherical cavity 12 of each half cage 10 axially faces (opposing) the hemispherical cavity 12 of the opposing half cage 10, such as to define a seat or cavity 7 defined by the spherical surface 8 with the hemispherical cavity 12 of the opposing half cage 10.

[0034] The annular cage 1 also comprises a connecting element, indicated in its entirety and generally with the reference numeral 13 , between the two half-cages 10 , designed to rigidly connect the two opposing half-cages 10 together to form the annular cage 1 , as if it were a single piece.

[0035] According to a first aspect of the invention, the connecting element 13 is designed with a first mechanical coupling portion 14 and a second mechanical coupling portion 15 ( Figure 2 ) connects the half cage 10, the first mechanical coupling portion 14 and the second mechanical coupling portion 15 are arranged in series with each other in the axial direction, and are designed to respectively and individually absorb the axial stress and tangential stress (stresses) experienced by the cage 1 when in use.

[0036] In particular, the first mechanical coupling portion 14 is composed of a plurality of first pairs of mating connection elements 16, 18 ( Figures 5 to 7 ) is formed, for each first pair of connecting elements 13 forming the mechanical coupling portion 14, the first pair of mating connecting elements 16, 18 includes an at least partially elastically deformable pin 16 and a corresponding hole 18 designed to receive the pin 16 by a snap-coupling.

[0037] Then, each half cage 10 is provided on the first front face 19 ( Figure 2 and Figure 6) is provided with a plurality of pins 16 protruding in the axial direction from the annular body 11, and on a second front face 20 ( Figure 2 and Figure 5 ) is provided with a corresponding plurality of holes 18 formed in the annular body 11 in the axial direction.

[0038] Therefore, the annular body 11 of each half cage 10 is provided with holes 18 and pins 16. The pins 16 and holes 18 are provided in equal numbers and are preferably arranged alternately in a row, in any case so that when the two half cages 10 are coupled head-on in the axial direction, each pin 16 of a half cage 10 is coupled with a facing hole 18 in the opposing half cage 10, in particular, each pin 16 of a half cage 10 passes through the opening of the hole 18 facing the first face 19 and is coupled with a facing hole 18 in the opposing half cage 10. The hole 18 is preferably a through hole opening into the face 20.

[0039] According to an important aspect of the present invention, the second mechanical coupling 15 is formed by a plurality of second pairs of mating connection elements 21, 22, and for each second pair forming the mechanical coupling 15, the second pair of mating connection elements 21, 22 comprises ( Figure 4 , Figure 6 and Figure 7 ) a male element 21 and a corresponding recess 22, the male element 21 being in the form of a substantially rigid solid block integral with the annular body 11, the male element 21 protruding axially from the first front face 19 of the annular body 11 of each half cage 10, and the corresponding recess 22 being designed to be rigidly connected to the solid block 21 forming the male element, the recess 22 passing through the first front face 19 of the annular body 11 of each half cage 10 and formed in the annular body 11.

[0040] Also in this case, each half cage 10 is provided with a plurality of convex elements and a corresponding plurality of recesses 22 formed as a rigid solid block 21, and the plurality of convex elements and the corresponding plurality of recesses 22 are preferably arranged alternately with each other in a row, so that each convex element 21 of the half cage 10 is connected to the facing recess 22 in the opposite half cage 10.

[0041] According to another basic aspect of the present invention, in order to form the coupling portions 14, 15 arranged in series in the axial direction, each pin 16 protrudes axially from a corresponding male element 21 formed by a solid block to be arranged in series with the male element 21 in the axial direction, and the position relative to the first front face 19 of the annular body 11 of each half cage 10 is downstream of the male element 21.

[0042] Similarly, each recess 22 is arranged axially in series with one such corresponding hole 18 , upstream of the hole 18 with respect to the position of the first front face 19 of the annular body 11 of each half-cage 10 .

[0043] By selecting specific types of connecting elements 16, 18 and 21, 22 and their specific relative positions, the mating connecting elements 21, 22 of the second pair of connecting elements 13 forming the mechanical connection part 15 are designed to receive the tangential component of the mechanical stress applied to the annular retaining frame 1 when in use, while the mating connecting elements 16, 18 of the first pair of connecting elements 13 forming the mechanical connection part 14 are designed to receive the axial component of the mechanical stress and keep the half retaining frames 10 in contact with each other, wherein the corresponding front faces 19 are arranged against each other in an axial abutment manner.

[0044] According to a preferred aspect of the invention, each solid block of shaped polymer material forming the male element 21 of the second pair of mating connecting elements 13 is wedge-shaped and preferably a truncated pyramid with a rectangular or square base, as is each corresponding recess 22, so that each solid block 21 is arranged via a surface 23 ( Figure 6 ) are coupled to the corresponding recessed portion 22. The inclined surfaces 23 face each other in pairs in the circumferential direction or in the radial direction (wedge-shaped), or face each other in pairs in both directions (truncated pyramid-shaped).

[0045] According to a preferred embodiment of the present invention ( Figure 6 ), each solid block 21 of the male element ( / male element) forming the second pair of mating connecting elements 13 is laterally provided with corresponding radial teeth or protrusions (reliefs) 24 in the circumferential direction, and the radial teeth or protrusions 24 are designed to be snap-coupled with the corresponding radial grooves 25 formed inside each recess 22.

[0046] Obviously, according to one possible variant not shown for the sake of simplicity, an alternative configuration could be used in which radial grooves 25 are formed laterally in the solid block forming male element 21 and radial teeth or protrusions 24 protrude circumferentially in recess 22 .

[0047] It is also obvious that possible inclined surfaces arranged facing each other in the circumferential direction of the solid block 21 and the recess 22 may be provided with teeth 24 and grooves 25 or may not be provided with teeth 24 and grooves 25 and vice versa.

[0048] According to another aspect of the invention, each at least partially hemispherical cavity 12 of each half cage 10 is provided at its respective opposite circumferential sides with two circumferentially shaped cavities 12 indicated by reference numerals 26 and 27, respectively. Figure 4 and Figure 6 ) are defined by a first axial lug and a second axial lug indicated by ), which are arranged adjacent to each other and protrude axially from the annular body 11 of each half-cage 10 on the side of the front face 19 .

[0049] Each axial lug 26 in turn bears a male element made of a solid block 21 and a pin 16 located on top of the male element or block 21 , the male element and the pin 16 being arranged to project axially in series away from the face 19 .

[0050] On the other hand, each axial lug 27 is formed to be hollow inside and delimits therein a respective inner recess 22. From the inside of each recess 22, a respective hole 18 axially away from the face 19, through the respective annular body 11 and then through the second front face 20.

[0051] The connecting element 13 includes a groove 25 and associated teeth or reliefs 24 ( Figure 3 and Figure 6 ) embodiment, the relative circumferential sides of the respective adjacent pairs of cavities 12 of the annular body 11 of each half cage 10 are the sides ( / flanks) of the respective opposite side walls 23 of each recess 22 provided with radial grooves 25 ( / flanks) of the respective opposite side walls 23 of each recess 22 provided with radial grooves 25.

[0052] The radial grooves 25 are designed to snap-couple in the circumferential direction with the radial teeth or protrusions 24 of the male element 21. As described above, according to one possible variation, radial teeth or protrusions 24 are formed on opposite side walls 23 of each recess 22 and are designed to snap-couple in the circumferential direction with the radial grooves 25, which in this case are formed on opposite sides of the male element 21 arranged in the circumferential direction.

[0053] According to another important aspect of the invention, each cavity 12 of the annular body 11 of each half-cage 10 is delimited axially towards the second front side 20 of the annular body 11 by a back wall, which in the example shown is spherical and defined by a portion of a spherical surface 8.

[0054] The rear wall 8 is provided with a depression 29 ( Figure 3 , Figure 4 and Figure 6 ), the recess 29 has an axial depth and a circumferential extension toward the second front side 20 to form a grease receiving chamber, so that when in use and when the half cage 10 is connected in the axial direction, the corresponding opposite sides of each seat or cavity ( / pocket) 7 for the rolling element 2 are defined by the relative grease receiving chamber defined by the recess 29, so that the recess 29 is in direct contact with the rolling element 2, and in addition, the recess 29 is in direct contact with the rolling element 2 at the original diameter or median diameter of the rolling bearing 3.

[0055] This optimizes the distribution of the grease over the rolling elements 2 during use, in particular when said rolling elements are balls, as in the preferred example embodiment shown.

[0056] According to another aspect of the invention, the spherical rear wall 8 ( Figure 4 ) is provided with a pair of radial grooves 30, which are parallel to each other and arranged near the opposite circumferential sides of the cavity 12 bounded by the axial lugs 26, 27. The grooves 30 pass through the recess 29 in the same cavity 12 in which the grooves are located, and are therefore interrupted by the recess 29 to be in hydraulic communication with the recess 29.

[0057] The grooves 30 are therefore designed to enable circulation of grease in each seat or cell 7 for a rolling element 2 during use.

[0058] In combination with this feature, the opposite circumferential sides of each at least partially hemispherical cavity 12 are formed on one side of the first front face 19 of the annular body 11 by opposite chamfers 31 ( Figure 4 ) is defined, the chamfer 31 is designed to form a relatively curved radial channel 32 ( Figure 2 ) for grease circulation for the rolling elements 2 arranged around each seat or cavity 7.

[0059] According to a highly preferred aspect of the invention, each half-cage 10 is provided radially outside with a substantially flange-shaped first radial annular ridge 34, which is formed near the second front face 20 of the annular body of each half-cage so as to be axially away from the seat or cavity 7 for the rolling elements 2.

[0060] The radial annular ridge 34 of each half cage 10 is designed to be in use ( / when in use) (in use) Figures 1 to 3 ) is coupled to an annular slot 35 formed radially inside the outer ring 4 of the rolling bearing 3 to form a labyrinth seal known as a whole with the annular slot 35.

[0061] In one possible implementation, for simplicity, Figure 3 As schematically illustrated using shaded lines, a second radial annular ridge 36 is optionally formed radially on the inner side of each half cage 10, is substantially flush with the first radial annular ridge 34, and is designed to be connected to a second annular groove 37 formed radially on the outer side of the inner ring 5 of the rolling bearing 3 during use ( / when in use), and also to form a labyrinth seal that is known as a whole with the second annular groove 37.

[0062] However, in order to improve the effect of the labyrinth seal and to simplify and compact the structure of the half cage 10, the radial annular ridge 34 ( Figure 2 and Figure 3 ) is disposed radially outside the axial relief 38. The axial relief 38 is formed radially inside the radial outer peripheral edge 39 of the annular ridge 34 to be away from the edge 39. The edge 39 preferably has a curved profile in radial section that matches the corresponding curved profile of the annular slot 35.

[0063] Based on the foregoing, the scope of the present invention clearly includes a rolling bearing unit 6, which includes a rolling bearing 3, which in turn includes an outer ring 4, an inner ring 5, a plurality of rolling elements 2 between the inner ring 5 and the outer ring 4 so that they can rotate relative to each other with low friction, and an annular retaining frame 1 for retaining the rolling elements 2 and between the inner ring 5 and the outer ring 4.

[0064] The annular cage 1 comprises a plurality of cells 7 , each cell being delimited by a respective spherical surface 8 having its centre situated in a radial mid-plane P of the cage 1 coinciding with a corresponding radial mid-plane of the rolling bearing 3 .

[0065] Furthermore, the cage 1 is formed by joining two half cages 10 which are substantially symmetrical with respect to the midplane P and connected together in the axial direction.

[0066] Each half cage 10 has an annular body 11 and a plurality of at least partially hemispherical cavities ( / hemispherical cavities) 12, which face the hemispherical cavities 12 of the opposite half cage 10 in the axial direction to define a cavity 7 with the hemispherical cavities 12 of the opposite half cage 10. The cage 1 also includes a connecting element 13 associated with the half cage 10 to connect the two half cages 10 together to form an annular cage 1.

[0067] These connecting elements 13 include in combination:

[0068] (i) A first pair of mating connecting elements, for each first pair, the first pair of mating connecting elements consists of at least partially elastically deformable pins 16 and corresponding holes 18 designed to receive the pins 16 by snap-fit ​​connection, each half-cage 10 is provided with a plurality of such pins 16 protruding axially from the annular body 11 on one side of a first front face 19 of the annular body 11, and a corresponding plurality of holes 18 formed axially in the annular body 11 on one side of a second front face 20 of the annular body 11 opposite to the first face 19, the annular body 11 of each half-cage 10 is provided with both the holes 18 and the pins 16, the holes 18 and the pins 16 being arranged alternately with one another in a row so that each pin 16 of the half-cage 10 passes through the opening of the hole 18 facing the first face 19 and is connected to the facing hole 18 in the opposite half-cage 10.

[0069] In combination with the foregoing, the connecting element 13 also includes a second pair of mating connecting elements, and for each second pair, the second pair of mating connecting elements includes a male element 21 and a corresponding recess 22, the male element 21 being designed to be a substantially rigid solid block protruding axially from the first front face 19 of the annular body 11 of each semi-retainer 10, and the corresponding recess 22 being designed to be rigidly connected to the solid block 21 forming the male element, and the recess 22 is formed through the first front face 19 of the annular body 11 of each semi-retainer 10.

[0070] Each half cage 10 is provided with a plurality of male elements 21 and a corresponding plurality of female portions 22 arranged alternately with each other in a row so that each male element 21 of a half cage 10 is coupled with a facing female portion 22 in an opposing half cage 10 .

[0071] Each pin 16 projects axially from a corresponding male element formed by a solid block 21 to be arranged axially in series with the male element and downstream of the male element with respect to the first front face 19 of the annular body 11 of each half-cage 10 .

[0072] Each recess 22 is also arranged axially in series with the corresponding hole 18 , upstream of the hole 18 with respect to the first front face 19 of each half-cage 10 .

[0073] Finally, each half-cage 10 as part of the rolling bearing unit 6 is provided with a first radial annular ridge 34 which is essentially flange-shaped on the radial outside, the first radial annular ridge 34 being formed near the second front side 20 of the annular body 11 of each half-cage 10 so as to be axially away from the seat or cavity 7 for the rolling elements 2.

[0074] The radial annular ridge 34 of each half cage 10 is coupled to an annular groove 35 formed radially on the inner side of the outer ring 4 of the rolling bearing 3 to form a labyrinth seal with the annular groove 35. A second radial annular ridge 36 is optionally formed radially on the inner side of each half cage 10, substantially flush with the first radial annular ridge 34, and coupled to a second annular slot 37 optionally formed radially on the outer side of the inner ring 5 of the rolling bearing 3 to form a labyrinth seal with the second annular slot 37.

[0075] Based on the foregoing, it is clear that, while known rolling bearings comprise one or two shields to prevent foreign dust particles from entering the bearing and to prevent grease losses, the described solution replaces the conventional shields with a symmetrical cage 1 having an additional shielding function. It is also possible to retain a smaller amount of grease in the bearing due to a special configuration in the design of the cells 7, which have a volume available for grease that is constant and easily adjustable during the design phase of the cage, in particular due to the presence and position of the recesses 29 in direct contact with the rolling elements.

[0076] When the cage is accelerated and decelerated due to the acceleration or deceleration of the bearing, the male element 21 formed on the pairs of corresponding adjacent axial lugs 26 and 27 coupled to the cavity 22 is subjected to tangential forces, thereby avoiding undesirable and / or excessive deformation of the cage 1, thereby maintaining the sealing effect of the annular ridges 34 and 36 (if present) in a frictionless (or friction-reduced) optimal state. The pin 16 snap-fitted in the hole 18 in a known manner blocks the half cage 10 in the axial direction.

[0077] In this way, all the objects of the invention are achieved.

Claims

1. An annular cage (1) for retaining rolling elements (2) in a rolling bearing (3), the annular cage (1) being configured to be mounted between a corresponding inner ring (5) and an outer ring (4) of the rolling bearing in use, and comprising a plurality of radially penetrating seats or cavities (7), the plurality of radially penetrating seats or cavities (7) being arranged in a row relative to each other and each being configured to accommodate a corresponding rolling element (2), the plurality of radially penetrating seats or cavities each being defined by a corresponding spherical surface (8), the spherical surface (8) having a center located in a radial midplane (P) of the cage, the radial midplane (P) coinciding with a corresponding radial midplane of the rolling bearing in use; the annular cage comprising: (a) - two half cages (10) axially opposite and substantially symmetrical with respect to said midplane, said two half cages (10) being connected to each other, each half cage (10) presenting an annular body (11) and a plurality of at least partially hemispherical cavities (12) axially facing the hemispherical cavities of the opposing half cage so as to define said seat or cell (7) with the hemispherical cavities of said opposing half cage; and (b) - a connecting element (13) for binding together two opposing half cages (10) so as to jointly form said annular cage (1); characterized by the fact that said connecting element (13) comprises in combination: (c) a first pair of conjugated connection elements, for each first pair, the first pair of conjugated connection elements being constituted by at least partially elastically deformable pins (16) and corresponding holes (18) configured to receive the pins (16) in a snap-fitting manner, each half-cage (10) being provided with a plurality of the pins (16) protruding axially from the annular body (11) on one side of a first front face (19) of the annular body, and a corresponding plurality of holes (18) obtained axially in the annular body (11) on one side of a second front face (20) of the annular body (11) opposite to the first face, the annular body of each half-cage (10) being provided with both the holes (18) and the pins (16), the holes (18) and the pins (16) being configured so that each pin (16) of the half-cage passes through the opening of the hole facing the first face (19) and cooperates with the hole (18) of the opposite half-cage facing the pin (16); and (d) a second pair of conjugated connecting elements, for each second pair, the second pair of conjugated connecting elements being constituted by a male element (21) and a corresponding female portion (22), the male element (21) being constructed as a substantially rigid solid block protruding in the axial direction from the first front face (19) of the annular body of each half cage, the corresponding female portion (22) being constructed to cooperate in an integral manner with the solid block (21) constituting the male element, the female portion (22) being obtained through the first front face (19) of the annular body of each half cage; each half cage (10) being provided with a plurality of the male elements (21) and a corresponding plurality of the female portions (22), the plurality of the male elements (21) and the corresponding plurality of the female portions (22) being configured so that each male element (21) of a half cage cooperates with a female portion (22) of the opposite half cage facing the male element (21); (e)-Each pin (16) protrudes axially from a corresponding convex element (21) formed by one of the solid blocks, so that it is arranged in series with the convex element (21) in the axial direction and is arranged downstream of the convex element (21) relative to the first front face (21) of the annular body (11) of each half retainer (10); and each recess (22) is arranged in series with the corresponding hole (18) in the axial direction and is arranged upstream of the hole (18) relative to the first front face (19) of the annular body of each half retainer.

2. The annular retainer according to claim 1, characterized in that The fact is that the conjugate connecting elements of the second pair of connecting elements (21, 22) are configured to receive the tangential component of the mechanical stress acting on the annular retainer in use, while the conjugate connecting elements of the first pair of connecting elements (16, 18) are configured to receive the axial component of the mechanical stress.

3. The annular retainer according to claim 2, characterized in that The fact that each of the solid blocks (21) constituting one of the male elements of the second pair of conjugated connecting elements and each corresponding recess (22) presents a truncated pyramid shape allows the connection between each solid block and the corresponding recess to be achieved by means of a surface (23) arranged obliquely with respect to the common axis of symmetry (A) of the opposing half-cages.

4. An annular cage according to any one of the preceding claims, characterized in that Each of the solid blocks constituting one of the male elements (21) in the second pair of conjugated connecting elements is laterally provided with a corresponding radial protrusion or tooth (24) in the circumferential direction, and the radial protrusion or tooth (24) is configured to be snap-fitted with a corresponding radial groove (25) obtained in each of the recesses (22); or, conversely, the radial groove (25) is machined laterally on the solid block (21) constituting the male element of the second pair of conjugated connecting elements, and the radial protrusion or tooth (24) protrudes circumferentially in the recess (22).

5. The annular retainer according to claim 4, characterized in that: Each of the at least partially hemispherical cavities (12) of each half cage is delimited on its respective opposite circumferential sides by a first axial lug (26) and a second axial lug (27) arranged adjacent to each other and protruding axially from the annular body (11) of each half cage, the first axial lug (26) in turn supporting a male element (21) and a pin (16) protruding in series axially and consisting of a solid block, the second axial lug (27) being hollow inside and defining a recess (22), the respective hole (18) axially departing from the interior of the recess (22), the hole (18) passing through the respective annular body The main body (11) is provided with a radial groove (25) on the side of the corresponding relative side wall of each recess (22) until the hole (18) intersects with the second front face (20); the relative circumferential sides of the corresponding adjacent pairs of the at least partially hemispherical cavities (12) of the annular main body of each of the semi-retainer are provided with the radial groove (25) on the side of the corresponding relative side wall of each recess (22), and the radial groove (25) is constructed to be snap-fitted with the radial teeth or protrusions (24) of the convex element in the circumferential direction, or conversely, the recess (22) is provided with the radial teeth or protrusions (24), and the radial teeth or protrusions (24) are constructed to be snap-fitted with the radial grooves (25) of the convex element in the circumferential direction.

6. An annular cage according to any one of the preceding claims, characterized in that Each of the at least partially hemispherical cavities (12) of the annular body (11) of each semi-retainer is defined by a spherical rear wall (8) axially toward the second front side (20) of the annular body, and the spherical rear wall (8) is provided with a recess (29) toward the first front side of the annular body, and the recess (29) develops in depth axially toward the second front side (20) and has a circumferential extension, and the recess (29) is constructed to constitute a grease receiving chamber, so that in use, when the semi-retainer (10) is connected axially, the corresponding opposite sides of each of the seats or cavities (7) for receiving the rolling elements (2) are defined by relative grease receiving chambers, and the relative grease receiving chambers are in direct contact with the rolling elements (2) at the median diameter or original diameter of the rolling bearing.

7. The annular retainer according to claim 6, characterized in that: The spherical rear wall (8) of each of the at least partially hemispherical cavities (12) is provided with a pair of radial grooves (30), the pair of radial grooves (30) are parallel to each other and are configured to be close to the relative circumferential sides of each at least partially hemispherical cavity (12), and the pair of radial grooves (30) are constructed to allow grease to circulate in the seat or cavity (7) of each rolling element during use; and, in combination, the relative circumferential side of each at least partially hemispherical cavity (12) is bounded by relative chamfers (31) on one side of the first front face (19) of the annular body, and the relative chamfers (31) are constructed to form relative curved radial channels (32) when the semi-retaining cage is connected in the axial direction, so as to realize the circulation of grease for the rolling elements configured around each seat or cavity (7) on the periphery.

8. An annular cage according to any one of the preceding claims, characterized in that Each half cage (10) is provided with a first radial annular ridge (34) on the radial outside, the first radial annular ridge (34) being shaped as a substantially flange and formed near the second front face (20) of the annular body of each half cage (10) so as to be axially away from the seat or cavity (7) for the rolling element; the first radial annular ridge (34) of each half cage is constructed to cooperate with an annular groove (35) obtained on the radial inside of the outer ring (4) of the rolling bearing during use, so as to perform a labyrinth sealing function together with the annular groove (35); a second radial annular ridge (36) is optionally obtained on the radial inside of each half cage (10), is substantially flush with the first radial annular ridge (34), and is constructed to cooperate with a second annular groove (37) obtained on the radial outside of the inner ring (5) of the rolling bearing during use, so as to perform a labyrinth sealing function together with the second annular groove (37).

9. The annular retainer according to claim 8, characterized in that The fact that the first radial annular ridge (34) is provided radially on the outside with an axial protrusion (38) is obtained radially on the inside at a distance from a radial outer peripheral edge (39) of the first ridge, the radial outer peripheral edge (39) having a curved profile in radial section.

10. A rolling bearing unit (6), comprising a rolling bearing (3), the rolling bearing (3) further comprising an outer ring (4), an inner ring (5), a plurality of rolling elements (2) interposed between the inner ring and the outer ring so that they can rotate relative to each other with low friction, and an annular retainer (1) retaining the rolling elements and installed between the inner ring and the outer ring; the annular retainer (1) comprising: - a plurality of cells (7), each delimited by a respective spherical surface (8) having a centre located in a radial mid-plane (P) of the cage, said radial mid-plane (P) coinciding with a corresponding radial mid-plane of the rolling bearing; - two half cages (10), substantially symmetrical with respect to said midplane and connected to each other, each half cage presenting an annular body (11) and a plurality of at least partially hemispherical cavities (12) axially facing the hemispherical cavities of the opposing half cage to define said cell (7) together with the hemispherical cavities of said opposing half cage; and - a connecting element (13) associated with said half cages to bind said two half cages together to form said annular cage; characterized by the fact that said connecting element (13) comprises in combination: (i) a first pair of conjugated connecting elements, for each first pair, the first pair of conjugated connecting elements being composed of at least partially elastically deformable pins (16) and corresponding holes (18) configured to receive the pins in a snap-fit ​​manner, each half cage (10) being provided with a plurality of the pins (16) protruding axially from the annular body on one side of a first front face (19) of the annular body, and a plurality of corresponding holes (18) formed axially in the annular body (11) on one side of a second front face (20) of the annular body (11) opposite to the first face, the annular body of each half cage being provided with both the holes (18) and the pins (16), the holes (18) and the pins (16) being configured so that each pin (16) of the half cage passes through the opening of the hole facing the first face (19) and cooperates with the hole (18) of the opposite half cage (10) facing the pin (16); and (ii) a second pair of conjugated connecting elements, for each second pair, the second pair of conjugated connecting elements consisting of a male element (21) and a corresponding female portion (22), the male element (21) being constructed as a substantially rigid solid block protruding in the axial direction from the first front face (19) of the annular body of each half cage, the corresponding female portion (22) being constructed to cooperate in an integral manner with the solid block (21) constituting the male element, the female portion (22) being obtained through the first front face (19) of the annular body of each half cage; each half cage (10) being provided with a plurality of the male elements (21) and a corresponding plurality of the female portions (22), the plurality of the male elements (21) and the corresponding plurality of the female portions (22) being configured so that each male element (21) of a half cage (10) cooperates with a female portion (22) of the opposite half cage (10) facing the male element (21); (iii) each pin (16) protrudes axially from a corresponding male element (21) constituted by one of the solid blocks so as to be arranged axially in series with the male element (21) and downstream of the male element (21) relative to the first front face (21) of the annular body of each half cage; and each recess (22) is arranged axially in series with the corresponding hole (18) and upstream of the hole (18) relative to the first front face (19) of the annular body of each half cage; (iv) each half-cage (10) is provided radially on the outside with a first radial annular ridge (34) shaped substantially flange-like and formed in the vicinity of said second front face (20) of the annular body (11) of each half-cage (10) so as to be axially remote from the seats or cells (7) for said rolling elements; The first radial annular ridge (34) of each half cage cooperates in an annular groove (35) obtained on the radial inner side of the outer ring (4) of the rolling bearing (3) to perform a labyrinth seal function together with the annular groove (35); A second radial annular ridge (36) is optionally obtained on the radial inner side of each half cage (10), is substantially flush with the first radial annular ridge (34), and is connected to a second annular groove (37) optionally obtained on the radial outer side of the inner ring (5) of the rolling bearing to perform a labyrinth seal function together with the second annular groove (37).

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