Bearing with optical sensor and associated groove

Abstract

The bearing comprises a first ring (10) and a second ring (12) which are rotatable concentrically relative to each other. At least one groove (50) is formed on an axial cylindrical surface (12b) of the second ring and is oriented toward the first ring (10). The groove is axially bounded by two side edges (50a, 50b). The bearing further comprises at least one optical sensor (24), which is mounted on the first ring to emit a light beam oriented toward at least one of the side edges (50a, 50b) of the groove of the second ring, the optical sensor (24) being capable of detecting the axial position of the side edge.

Description

Technical Field

[0001] The present invention relates to the field of bearings.

[0002] The invention relates in particular to the field of large diameter rolling bearings which are able to accommodate axial loads and radial loads and have an inner ring and an outer ring which are arranged concentrically around an axis of rotation extending in the axial direction. Background Art

[0003] Such large-diameter rolling bearings can be used, for example, in tunnel boring machines, mining machines or wind turbines.

[0004] Large diameter rolling bearings include two concentric inner and outer rings and at least two rows of rolling elements, such as rollers, arranged between the inner and outer rings. Such rolling bearings are usually loaded in both axial and radial directions, often with relatively large loads. In this case, reference is made to orientation roller bearings or slewing roller bearings.

[0005] Due to the heavy loads, the components of the rolling bearing, more particularly the raceways of the rolling elements, wear. The wear of the rings and rolling elements leads to a significant increase in the initial bearing clearance. Wear exceeding a certain value can lead to severe bearing failure.

[0006] Measuring bearing wear through the increase in clearance (causing relative axial and radial displacement of the rings) helps predict the remaining life of the bearing.

[0007] This unwanted movement affects the correct function of the bearing and the application, with the risk of the bearing rings touching and colliding. Other elements attached to the bearing rings may also collide.

[0008] It is common to replace bearings when they are worn. Such maintenance interventions are expensive, especially because the machine or facility needs to be shut down. It is therefore desirable to perform such maintenance interventions in a timely manner, but not too early, before any contact occurs between the bearing rings.

[0009] In order to monitor the bearing condition during its service life, the rolling bearing disclosed in patent application FR-A1-3041396 comprises an annular magnetic target fixed to the inner ring and a sensor mounted on the outer ring and facing the magnetic target. Thus, the axial relative movement and the angular relative movement between the inner ring and the outer ring can be detected.

[0010] However, this requires the annular magnetic target to be mounted on an inner ring which may be several meters in diameter.

[0011] Furthermore, when using such a magnetic target, the measurement of the axial displacement between the inner and outer rings is affected by the radial displacement. In fact, when measuring the axial displacement of a magnetic target, the air gap between the target and the sensor changes with the radial relative motion between the rings, making the measurement less accurate or even impossible. Summary of the invention

[0012] An object of the present invention is to overcome these disadvantages.

[0013] The invention relates to a bearing comprising a first ring and a second ring which are rotatable concentrically relative to each other.

[0014] According to a general feature, at least one groove is formed on the axial cylindrical surface of the second ring and is oriented towards the first ring. The groove is delimited in the axial direction by two side edges.

[0015] According to another general characteristic, the bearing further comprises at least one optical sensor mounted on the first ring to emit a light beam directed towards at least one of the side edges of the grooves of the second ring. The optical sensor is capable of detecting the axial position of the side edge.

[0016] Thanks to the invention, it is possible to accurately detect the axial relative displacement between the rings (first and second ring). In fact, the axial position of the groove formed on the second ring relative to the first ring is detected by the optical sensor. Moreover, it is not necessary to mount an annular magnetic target on one of the rings. The groove can be easily machined on the associated ring.

[0017] Preferably, the groove is annular. Thus, axial relative displacement between the rings can be detected regardless of the rotational position of the rings.

[0018] Advantageously, the optical sensor remains radially spaced from the axial cylindrical surface of the first ring, which radially faces the axial cylindrical surface of the second ring in which the groove is formed. This reduces the risk of contaminants such as grease, dust, water reaching the optical sensor.

[0019] The side edges of the grooves of the second ring may extend at least partially radially.

[0020] In one embodiment, the groove comprises at least one tapered bevel extending from one of the side edges and connected to the axial cylindrical surface of the second ring in which the groove is formed. With this design, contaminants that could affect the measurement of the optical sensor do not remain in the groove. However, in a variant, the groove may be free of such a tapered bevel.

[0021] In a particular embodiment, at least one of the side edges of the groove has a stepped form, the side edge having the stepped form having at least a first radial portion connected to the axial cylindrical surface of the second ring in which the groove is formed, and having at least a second radial portion offset axially toward the other side edge of the groove relative to the first radial portion. With this design, contaminants that may cover the first radial portion of the side edge do not affect the detection of the position of the second radial portion by the optical sensor.

[0022] Advantageously, the first ring includes a through hole in which the optical sensor is arranged. The through hole of the first ring may extend radially from an axial cylindrical surface located radially on a side opposite to the second ring and open on an opposite axial cylindrical surface of the first ring, the opposite axial cylindrical surface radially facing the axial cylindrical surface of the second ring in which the groove is formed.

[0023] Thereby, the sensor is inserted into the through hole and arranged in its final position in an easy manner. The first ring may also comprise a plug sealing the through hole.

[0024] In one embodiment, the bearing further comprises at least one row of rolling elements and a first seal and a second seal, wherein the at least one row of rolling elements is arranged between raceways provided on the first ring and the second ring, the first seal and the second seal are arranged between the first ring and the second ring and together define a closed rolling space, and the row of rolling elements is accommodated in the closed rolling space.

[0025] Advantageously, the bearing further comprises at least one additional seal, which is located inside the closed rolling space and defines, together with one of the first seal and the second seal, a closed detection space, the interior of which opens into the groove.

[0026] In one embodiment, the bearing includes at least one row of axial rolling elements arranged between radial raceways provided on the first ring and the second ring, and at least one row of radial rolling elements arranged between axial raceways provided on the first ring and the second ring, the second ring including a protruding nose, the protruding nose engaging in the annular groove of the first ring and providing an axial raceway of the second ring.

[0027] The term "axial rolling element" is understood to mean a rolling element adapted to accommodate axial loads, whereas the term "radial rolling element" is understood to mean a rolling element adapted to accommodate radial loads.

[0028] The nose of the second ring may protrude radially from the axial cylindrical surface of the second ring in which the groove is formed ( / protrude radially from the axial cylindrical surface of the second ring in which the groove is formed). The nose of the second ring may also be provided with two radial flanks ( / flanks) axially delimiting the axial cylindrical surface, one of the radial flanks at least partially delimiting the radial raceway of the second ring.

[0029] In one embodiment, the bearing comprises at least two rows of axial rolling elements respectively arranged between radial raceways provided on the first ring and the second ring, and the at least two rows of axial rolling elements are axially arranged on both sides of the nose of the second ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The invention and its advantages will be better understood by studying the detailed description of a particular embodiment given by way of non-limiting example and illustrated by the accompanying drawings, in which:

[0031] - Figure 1 is a partial cross section of a rolling bearing according to a first example of the present invention, and

[0032] - Figure 2 is a partial cross section of a rolling bearing according to a second example of the present invention. DETAILED DESCRIPTION

[0033] like Figure 1 The rolling bearing shown above is a large diameter rolling bearing comprising a first ring 10 and a second ring 12. In the example shown, the first ring 10 is an outer ring and the second ring 12 is an inner ring. The rolling bearing can be used, for example, in tunnel boring machines, wind turbines or any other application using large diameter rolling bearings.

[0034] The outer ring 10 and the inner ring 12 are concentric and extend axially along a bearing rotation axis XX' extending in the axial direction. The rings 10, 12 are of the solid type.

[0035] The outer ring 10 is formed as a split ring and includes a first ring 14 and a second ring 16 stacked relative to each other in the axial direction. Each of the first ring 14 and the second ring 16 of the outer ring is provided with a plurality of aligned through holes (not shown) for engagement by assembly bolts.

[0036] In the example shown, the rolling bearing comprises two rows of axial rollers 18 , 20 arranged between the outer ring 10 and the inner ring 12 to form an axial thrust, and one row of radial rollers 22 arranged between the outer ring 10 and the inner ring 12 to form a radial thrust.

[0037] As will be described later, the rolling bearing further comprises an optical sensor 24 for detecting an axial relative displacement between the outer ring 10 and the inner ring 12. In the example shown, the optical sensor 24 is mounted on the outer ring 10.

[0038] The rollers 18, 20, 22 in a row are identical to one another. Each roller 18, 20, 22 comprises a cylindrical outer rolling surface and two opposite front end surfaces delimiting the outer rolling surface. The axis of rotation of each roller 22 is parallel to the axis XX' of the bearing and perpendicular to the axis of each roller 18, 20. In the example shown, the axial length of the roller 18 is greater than the axial length of the roller 20. As another option, the axial length of the roller 18 may be less than or may be equal to the axial length of the roller 20.

[0039] The rollers 18 are axially arranged between annular radial raceways 26, 28 formed respectively on the inner ring 12 and the outer ring 10. Each radial raceway 26, 28 has a straight inner profile in cross section that contacts the rolling surface of the rollers 18. The raceways 26, 28 face each other in the axial direction.

[0040] The rollers 20 are arranged axially between annular radial raceways 30, 32 formed on the inner ring 12 and the outer ring 10, respectively. Each radial raceway 30, 32 has a straight inner profile in cross section that contacts the rolling surface of the roller 20. The raceways 30, 32 face each other in the axial direction. The rows of rollers 18, 20 are spaced apart from each other in the axial direction.

[0041] The rollers 22 are arranged radially between annular axial raceways 34, 36 formed on the inner ring 12 and the outer ring 10, respectively. Each axial raceway 34, 36 has a straight inner profile in cross section that contacts the rolling surface of the roller 22. The raceways 34, 36 face each other in the radial direction. The row of rollers 22 is offset radially outward relative to the rows of rollers 18, 20. The row of rollers 22 is located axially between the row of rollers 18 and the row of rollers 20.

[0042] The outer ring 10 comprises an annular groove 38 which is open inwardly in the radial direction towards the inner ring 12. The outer ring 10 comprises a stepped inner cylindrical surface or hole 10a, by which the groove 38 is formed. The outer ring 10 also comprises an outer cylindrical surface 10b which is radially opposite ( / opposite) to the hole 10a. The outer ring 10 also comprises two oppositely facing radial front surfaces 10c, 10d which axially delimit the hole 10a and the outer surface 10b of the ring.

[0043] The inner ring 12 comprises an annular projecting nose 40 which engages in the annular groove 38 of the outer ring. The nose 40 extends radially outwards.

[0044] The inner ring 12 comprises an inner cylindrical hole 12a and a stepped outer cylindrical surface 12b radially opposite the hole 12a. In the example shown, the hole 12a of the inner ring is provided with gear teeth (not shown). The inner ring 12 also comprises two radial front surfaces 12c, 12d facing away from each other, which define the hole 12a and the outer cylindrical surface 12b in the axial direction. The protruding nose 40 protrudes radially from the outer cylindrical surface 12b.

[0045] The rows of rollers 18, 20 are arranged axially between the nose 40 of the inner ring and the groove 38 of the outer ring. The rows of rollers 18, 20 are arranged on both sides of the nose 40 of the inner ring. The radial raceway 26 is located on the nose 40 and on the radial portion of the stepped outer cylindrical surface 12b of the inner ring. As another option, the radial raceway 26 can be completely located on the nose 40. The radial raceway 30 is located on the nose 40. The radial raceways 28, 32 are located on the groove 38 of the outer ring.

[0046] More precisely, the first radial side ( / flank) of the nose 40 partially defines the radial raceway 26 for the rollers 18. The first radial side of the groove 38 (the first radial side facing the nose 40 in the axial direction) defines the radial raceway 28 for the rollers 18. The second side of the nose 40 and the facing second side of the groove 38 define the radial raceways 30, 32 for the rollers 20, respectively. The first and second sides of the nose 40 facing away define the nose in the axial direction. Similarly, the first and second sides of the groove 38 opposite to each other define the groove in the axial direction. Each of the first and second sides of the nose 40 extends radially from the outer cylindrical surface 12b of the inner ring.

[0047] The row of rollers 22 is arranged radially between the nose 40 of the inner ring and the groove 38 of the outer ring. The axial raceways 34, 36 are located on the nose 40 and the groove 38, respectively. The outer cylindrical surface of the nose 40 defines the axial raceway 34. The outer cylindrical surface of the nose 40 and the outer cylindrical surface 12b are offset radially. Therefore, the axial raceway 34 and the outer cylindrical surface 12b are also offset radially. The outer cylindrical surface of the nose 40 extends axially between the opposite radial sides of the nose.

[0048] The axial bottom of the groove 38 defines the axial raceway 36. In the example shown, an annular slot 41 is formed in the bottom of the groove 38 and defines the axial raceway 36. The axial raceway 36 radially faces the outer cylindrical surface of the nose 40 on which the axial raceway 34 is formed.

[0049] In the example shown, the inner ring 12 is made in one piece. As another option, the inner ring 12 can be divided in the axial direction into at least two separate parts fixed together. In another variant, the nose 40 can be made separately from the main part of the inner ring.

[0050] As mentioned before, the outer ring 10 is divided into two separate parts in the axial direction, namely the first ring 14 and the second ring 16. The first ring 14 and the second ring 16 together define the groove 38. The radial raceway 28 is located on the first ring 14 and the radial raceway 32 is located on the second ring 16 of the outer ring.

[0051] The rolling bearing also comprises annular seals 42, 44 on both sides mounted on the inner ring 12 and arranged to close the radial space existing between the rings 10, 12. This radial space is defined between the bore 10a of the outer ring and the outer cylindrical surface 12b of the inner ring and the outer surface of the nose 40.

[0052] A closed space 46 is defined between the inner and outer rings 12 , 14 and the seals 42 , 44 , and the rows of rolling elements 18 , 20 and 22 are accommodated in the closed space 46 .

[0053] Each seal 42, 44 is installed in a groove (not shown) formed on the outer cylindrical surface 12b of the inner ring and contacts the outer ring 10. The seal 42 contacts the radial front surface 10c of the outer ring. The seal 44 contacts the holes 10a of the outer ring that are axially close to the row of rollers 18. As another option, at least one of the seals 42, 44 can be provided with an opposite configuration so that the seal is installed on the outer ring 10 and is in friction contact with the inner ring 12.

[0054] As mentioned above, the optical sensor 24 is arranged to detect the axial relative displacement between the outer ring 10 and the inner ring 12. To this end, an annular groove 50 is also formed on the inner ring. In the example shown, the groove 50 is formed on the outer cylindrical surface 12b of the inner ring.

[0055] In the example shown, the sensor 24 radially faces the groove 50 of the inner ring. The outer ring 14 is provided with a radial through hole 52, and the sensor 24 is located inside the radial through hole 52. The through hole 52 extends from the outer surface 10b of the outer ring and opens on the hole 10a. The through hole 52 radially faces the groove 50 of the inner ring.

[0056] The sensor 24 is mounted in the through hole 52 and is kept radially spaced apart from the hole 10 a of the outer ring. Preferably, the through hole 52 has a shape complementary to that of the sensor 24 .

[0057] The outer ring 10 further comprises a plug 54 which closes and seals the through hole 52. The plug 54 is radially located in the through hole 52. The plug 54 is fixed inside the through hole 52 by any suitable means, such as by press fitting. The plug 54 is flush with the outer cylindrical surface 10b of the outer ring.

[0058] The optical sensor 24 includes a sensor body 56 mounted inside the through hole 52 of the outer ring. The sensor body 56 is fixed inside the through hole 52 by any suitable means, such as by press fitting.

[0059] In the disclosed example, the optical sensor 24 also includes an output connection cable 58 for transmitting sensed data, which extends outward relative to the sensor body 56. The output cable 58 extends outward in the radial direction. The plug 54 is provided with a through hole (not shown) that enables the output cable 58 to pass therethrough. The output cable 58 connects the sensor 24 to a control unit (not shown) to transmit the sensed measurement value. As another option, in the case of a wireless sensor, the sensor 24 may not have such an output cable.

[0060] The sensor body 56 of the sensor has a longitudinal axis 60 extending in radial direction. The axis 60 also forms the optical axis of the sensor 24. The sensor 24 emits a light beam 61 (schematically shown in dashed lines) directed towards the outer cylindrical surface 12b of the inner ring and the groove 50.

[0061] For example, the light beam emitted from the sensor 24 can be projected as a line on the outer cylindrical surface 12b of the inner ring and the groove 50. As another option, the projected light beam of the sensor can have other shapes, such as a circle. For example, the light beam emitted from the sensor 24 is a light beam or a laser beam. The light beam can be an invisible light beam or a visible light beam.

[0062] The groove 50 extends radially inward from the outer cylindrical surface 12b of the inner ring. The groove 50 is axially bounded by two side walls or side edges 50a, 50b. The side edges 50a, 50b face each other in the axial direction. The side edges 50a, 50b are spaced apart from each other in the axial direction. The groove 50 also includes a bottom 50c connected to the side edges 50a, 50b. The outer cylindrical surface 12b of the inner ring and the bottom 50c of the groove are offset in the radial direction.

[0063] In the example shown, the side edges 50a, 50b of the groove extend in the radial direction, and the bottom 50c extends in the axial direction. The groove 50 has a rectangular cross section. As another option, the groove 50 can have a cross section of other shapes, such as a V-shaped cross section. In this case, the side edges 50a, 50b of the groove extend obliquely, and the groove can be provided with or without a bottom 50c.

[0064] In the example shown, the groove 50 also includes a tapered bevel 50d extending from the side edge 50a and connected to the outer cylindrical surface 12b. It is foreseen that such a tapered bevel 50d will not retain contaminants within the groove 50 that could affect the measurement of the sensor 24.

[0065] To this end, the rolling bearing further comprises an additional seal 62 disposed inside the closed space 46 defined by the seals 42, 44. The seal 62 is located axially near the seal 42. The seal 62 is axially arranged between the seal 42 and the row of axial rollers 20. In the example shown, the seal 62 is mounted in a groove (not shown) formed on the outer cylindrical surface 12b of the inner ring and is in contact with the outer ring 10. The seal 42 is in contact with the hole 10a of the outer ring near the through hole 52. As another option, the seal 62 can be mounted on the outer ring 14 and in frictional contact with the inner ring 12.

[0066] The seal 62 defines a closed detection space 64 radially between the outer ring 10 and the inner ring 12 together with the seal 42, and the interior of the detection space 64 leads to the groove 50 of the inner ring and the through hole 52 of the outer ring. Only the groove 50 and the through hole 52 are located inside the detection space 64. There is no roller row inside the detection space 64.

[0067] The light beam emitted by the sensor 24 is oriented toward the outer cylindrical surface 12b of the inner ring and the groove 50, in particular toward the side edges 50a, 50b of the groove. The light beam is reflected by the outer cylindrical surface 12b and the groove 50. The sensor 24 is capable of detecting the position of the side edges 50a, 50b. For example, the sensor 24 may include a measurement mode for at least one edge position. Preferably, the sensor 24 has no deflector. For example, the sensor 24 may be a PosCon sensor available from Baumer.

[0068] This axial displacement of the groove side edges 50a, 50b is detected by the sensor 24 as they move through the light beam emitted by the sensor 24. Thus, axial displacement of the groove 50 (and more generally the inner race 12) relative to the outer race 10 is detected by the sensor 24.

[0069] Figure 2 The example shown above (where the same parts are given the same reference numerals) differs from the previous example only in that the side edge 50b of the groove 50 of the inner ring has a stepped form ( / stepped form). The side edge 50b is provided with a first radial portion connected to the axial cylindrical surface 12b of the second ring, and is provided with a second radial portion offset axially toward the side edge 50a relative to the first radial portion. The second radial portion of the side edge 50b is connected to the bottom 50c. The side edge 50b is also provided with an annular axial portion extending between the first radial portion and the second radial portion.

[0070] With this design of the groove, contaminants that may cover the first radial portion of the side edge 50 b do not affect the detection of the position of the second radial portion by the sensor 24 .

[0071] In the example shown, the light beam emitted by the sensor 24 is directed towards both side edges 50a, 50b of the slot. As another alternative, the light beam of the sensor 24 may be directed towards only one of the side edges 50a, 50b.

[0072] In the example shown, the optical axis 60 of the sensor extends in the radial direction. As another option, the optical axis 60 of the sensor can extend obliquely. However, in this case, it may not be possible to use the radial through hole 52 to achieve the installation of the sensor 24 on the outer ring. In this case, the sensor 24 may not face the groove 50 in the radial direction.

[0073] In the example shown, the groove 50 is formed on the outer cylindrical surface 12b of the inner ring axially between the row of axial rollers 20 and the seal 42. As another option, depending on the design of the rolling bearing, the groove can be provided on another area of ​​the outer cylindrical surface 12b. In a variant, the groove 50 can also be provided on the outer cylindrical surface of the nose 40 of the inner ring on which the axial raceway 34 is formed. In this case, the sensor 24 is axially located between the row of radial rollers 22 and the row of axial rollers 20 or 18.

[0074] Alternatively, as previously mentioned, in the example shown, the first ring of the rolling bearing is the outer ring 10 and the second ring is the inner ring 12 .

[0075] As an alternative, the opposite configuration can be provided, with the first ring forming the inner ring and the second ring forming the outer ring. In this case, the groove 50 is formed on the axially inner cylindrical surface of the outer ring, the axially inner cylindrical surface of the outer ring forming the hole of the outer ring, and the optical sensor 24 is mounted on the inner ring.

[0076] In the example described, the rolling bearing is provided with three rows of rolling elements. As another option, the rolling bearing may include only one row of rolling elements, or two rows of rolling elements, or four or more rows of rolling elements. In the example shown, the rolling elements are rollers. The rolling bearing may include other types of rolling elements, such as balls. In another variant, the bearing may also be a sliding bearing without rolling elements.

Claims

1. A bearing comprising a first ring (10) and a second ring (12) which are rotatable concentrically relative to each other, characterized in that: At least one groove (50) is formed on the axial cylindrical surface (12b) of the second ring and is oriented toward the first ring (10), the groove being axially bounded by two side edges (50a, 50b), the bearing further comprising at least one optical sensor (24), the at least one optical sensor (24) being mounted on the first ring to emit a light beam oriented toward at least one of the side edges (50a, 50b) of the groove of the second ring, the optical sensor (24) being capable of detecting the axial position of the at least one side edge.

2. The bearing according to claim 1, characterized in that: The groove (50) of the second ring is annular.

3. The bearing according to claim 1 or 2, characterized in that: The optical sensor (24) is maintained radially spaced from the axial cylindrical surface (10a) of the first ring, which radially faces the axial cylindrical surface (12b) of the second ring in which the groove (50) is formed.

4. The bearing according to claim 1 or 2, characterized in that: The side edges (50a, 50b) of the grooves of the second ring extend at least partially in the radial direction.

5. The bearing according to claim 4, characterized in that: The groove (50) of the second ring includes at least one tapered slope (50d) extending from one of the side edges (50a, 50b) and connected to the axial cylindrical surface (12b) of the second ring where the groove is formed.

6. The bearing according to claim 4, characterized in that: At least one of the side edges (50b) of the groove (50) has a stepped form, and the side edge (50b) having the stepped form has at least a first radial portion connected to the axial cylindrical surface (12b) of the second ring on which the groove is formed, and has at least a second radial portion offset axially toward the other side edge (50a) of the groove relative to the first radial portion.

7. The bearing according to claim 1 or 2, characterized in that: The first ring (10) comprises a through hole (52), and the optical sensor (24) is arranged in the through hole (52).

8. The bearing according to claim 7, characterized in that The through hole (52) of the first ring extends radially from an axial cylindrical surface (10b) located radially on a side opposite to the second ring, and opens on an opposite axial cylindrical surface (10a) of the first ring, the opposite axial cylindrical surface (10a) radially facing an axial cylindrical surface (12b) of the second ring on which the groove (50) is formed.

9. The bearing according to claim 1 or 2, characterized in that: The bearing further comprises at least one row of rolling elements (18; 22) and a first seal (42) and a second seal (44), wherein the at least one row of rolling elements (18; 22) is arranged between raceways (28, 26; 36, 34) provided on the first ring and the second ring, wherein the first seal (42) and the second seal (44) are arranged between the first ring and the second ring and together define a closed rolling space (46), wherein the row of rolling elements (18; 22) is accommodated in the closed rolling space (46), and wherein the bearing further comprises at least one additional seal (62), wherein the at least one additional seal (62) is located inside the closed rolling space (46) and together with one of the first seal (42) and the second seal (44) define a closed detection space (64), wherein the closed detection space (64) leads to the groove (50).

10. The bearing according to claim 1 or 2, characterized in that: The bearing comprises at least one row of axial rolling elements (18) arranged between radial raceways (26, 28) provided on the first ring and the second ring and at least one row of radial rolling elements (22) arranged between axial raceways (34, 36) provided on the first ring and the second ring, the second ring (12) comprising a protruding nose (40) which engages in an annular groove (38) of the first ring and provides an axial raceway (34) of the second ring, the nose (40) protruding radially from an axial cylindrical surface (12b) of the second ring on which the groove (50) is formed.

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