Bearing with distance sensor and tapered 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 tapered groove (50) is formed on a first axial cylindrical surface (12b) of the second ring and is oriented toward the first ring (10). The bearing further comprises: at least one first distance sensor (24) mounted on the first ring and facing a tapered wall (50a) of the tapered groove of the second ring, the tapered wall (50a) being inclined relative to an axis (X-X') of the bearing, the longitudinal axis (60) of the first distance sensor (24) being perpendicular to the axis (X-X'), and at least one second distance sensor (25) mounted on the first ring and different from the first distance sensor (24), the second distance sensor (25) facing the second axial cylindrical surface of the second ring in a radial direction.

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 a rotation axis 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 the service life of the bearing, 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 general characteristics, at least one tapered groove is formed on the first axial cylindrical surface of the second ring and is oriented towards the first ring.

[0015] According to another general characteristic, the bearing further comprises: at least one first distance sensor mounted on the first ring and facing the conical wall of the conical groove of the second ring, the conical wall being inclined relative to the axis of the bearing. The longitudinal axis of the first distance sensor is perpendicular to the axis.

[0016] The bearing further comprises: at least one second distance sensor mounted on the first ring and spaced apart from the first distance sensor. The second distance sensor radially faces the second axial cylindrical surface of the second ring.

[0017] Thanks to the invention, the axial relative displacement between the rings (first and second) can be detected accurately. In fact, the axial position of the tapered groove formed on the second ring relative to the first ring can be calculated from the total displacement detected by the first distance sensor and the pure radial displacement detected by the second distance sensor.

[0018] Therefore, the radial clearance of the bearing can also be measured by using the second distance sensor at the same time.

[0019] Furthermore, there is no need to mount an annular magnetic target on one of the rings. The grooves can be easily machined on the associated ring.

[0020] The tapered wall of the tapered groove may be the tapered bottom of the groove or any other tapered portion of the groove.

[0021] Preferably, the groove is annular. Thus, axial relative displacement between the rings can be detected regardless of the rotational position of the rings.

[0022] Advantageously, the bearing further comprises a control unit connected to the first distance sensor and the second distance sensor and adapted to calculate the value of the relative axial displacement Da between the first ring and the second ring based on the following formula:

[0023] in,

[0024] -ΔM is the value of the differential measurement of the first distance sensor on the conical wall of the second circle,

[0025] Dr is the value of the relative radial displacement between the first circle and the second circle detected by the second distance sensor, and

[0026] - α is the value of the angle formed in a radial plane of the bearing between the tapered wall of the tapered groove and the first axial cylindrical surface of the second ring.

[0027] The control unit may be located remote from the components of the bearing. Alternatively, the control unit may be mounted on one of the components of the bearing, for example the first ring or the second ring.

[0028] Advantageously, the first ring comprises at least a first through hole in which the first distance sensor is at least partially arranged and a second through hole in which the second distance sensor is at least partially arranged. Each through hole of the first ring may extend radially from an axial cylindrical surface located radially on a side opposite to the second ring (or, in other words, radially extend from the surface) and open on an opposite axial cylindrical surface of the first ring radially facing the second ring.

[0029] Thus, each of the first and second sensors is inserted in a simple manner into the associated through-hole and arranged in its final position. The first ring further comprises a first plug and a second plug sealing the first and second through-holes, respectively.

[0030] In one embodiment, the first axial cylindrical surface of the second ring is radially offset from the second axial cylindrical surface. Thus, in this case, the first axial cylindrical surface and the second axial cylindrical surface are different from each other. As an option, the first axial cylindrical surface and the second axial cylindrical surface can be the same cylindrical surface.

[0031] In one embodiment, the first distance sensor and the second distance sensor are spaced apart from each other in a circumferential direction.

[0032] In one embodiment, the bearing further comprises at least one row of rolling elements arranged between raceways provided on the first ring and the second ring.

[0033] The bearing may further include a first seal and a second seal disposed between the first race and the second race and defining together a closed rolling space, the row of rolling elements and the first distance sensor and the second distance sensor being accommodated inside the closed rolling space.

[0034] In one embodiment, the bearing may further include at least one additional seal, which is located inside the closed rolling space and defines a closed detection space together with one of the first seal and the second seal, wherein the interior of the closed detection space leads to the tapered groove.

[0035] 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 into the annular groove of the first ring and providing the second axial cylindrical surface, the axial raceway of the second ring being formed on the second axial cylindrical surface.

[0036] 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.

[0037] The nose of the second ring may protrude radially from the first axial cylindrical surface of the second ring formed with the tapered groove. The nose of the second ring may also be provided with two radial flanks (flanks) axially delimiting the second axial cylindrical surface, one of the radial flanks at least partially delimiting the radial raceway of the second ring.

[0038] 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.

[0039] In one embodiment, the first distance sensor and / or the second distance sensor may be a non-contact measurement sensor, ie, a proximity sensor, such as an inductive sensor, an ultrasonic sensor or an optical sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] 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:

[0041] - Figure 1 is a partial cross section of a rolling bearing according to an example of the present invention, and

[0042] - Figure 2 yes Figure 1 Detail of a bearing diagram schematically illustrating the axial displacement of one bearing ring relative to the other. DETAILED DESCRIPTION

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] As will be described later, the rolling bearing further comprises a first distance sensor 24 and a second distance sensor 25 for detecting the axial relative displacement between the outer ring 10 and the inner ring 12. In the example shown, the sensor 24 is mounted on the outer ring 10. Each of the sensors 24, 25 measures the radial distance from the inner ring 12. The "radial distance from the inner ring 12" is understood to mean the distance from the inner ring 12 relative to a radial direction, which is perpendicular to the axis XX' of the bearing.

[0048] 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 an alternative, the axial length of the roller 18 may be less than or may be equal to the axial length of the roller 20.

[0049] 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.

[0050] 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.

[0051] 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 ( / staggered) radially outward relative to the row of rollers 18, 20. The row of rollers 22 is located axially between the row of rollers 18 and the row of rollers 20.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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 an 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.

[0056] More precisely, the first radial side ( / flank) of the nose 40 partially defines the radial raceway 26 for the roller 18. The first radial side of the groove 38, which faces the first radial side of the nose 40 in the axial direction, defines the radial raceway 28 for the roller 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 roller 20, respectively. The first and second sides of the nose 40 facing away from each other define the nose in the axial direction. Similarly, the first and second sides of the groove 38 opposite 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.

[0057] 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 radially staggered ( / offset). Therefore, the axial raceway 34 and the outer cylindrical surface 12b are also radially staggered ( / offset). The outer cylindrical surface of the nose 40 extends axially between the opposite radial sides of the nose.

[0058] 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.

[0059] In the example shown, the inner ring 12 is made in one piece. As an alternative, 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.

[0060] 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.

[0061] 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.

[0062] A closed space 46 is defined between the inner and outer rings 12 and 14 and the seals 42 , 44 , and the rows of rolling elements 18 , 20 , and 22 and the first and second distance sensors 24 , 25 are accommodated in the closed space 46 .

[0063] 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 hole 10a of the outer ring near the row of rollers 18 in the axial direction. As an 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 in friction contact with the inner ring 12.

[0064] As mentioned above, the first distance sensor 24 and the second distance sensor 25 are arranged to detect the axial relative displacement between the outer ring 10 and the inner ring 12. To this end, an annular tapered groove 50 is also formed on the inner ring 12. In the example shown, the groove 50 is formed on the outer cylindrical surface 12b of the inner ring.

[0065] The groove 50 extends radially inward from the outer cylindrical surface 12b of the inner ring. The groove 50 includes an annular tapered portion or tapered wall 50a extending obliquely inward. The tapered wall 50a has a truncated cone shape. The tapered wall 50a is inclined relative to the axis XX' of the rolling bearing. In other words, the tapered wall 50a is formed to be inclined relative to the axis XX'. The tapered wall 50a is inclined relative to the axial cylindrical surface 12b of the inner ring. In the case of Figure 1 In the radial plane of the rolling bearing shown above, an angle α is formed between the conical wall 50a of the groove and the axial cylindrical surface 12b. For example, preferably, the value of the angle α may be comprised between 15° and 30°.

[0066] In the example shown, the tapered wall 50a extends from the outer cylindrical surface 12b of the inner ring. As an alternative, the groove may be provided with an annular radial wall extending radially inwardly from the outer cylindrical surface 12b, and the tapered wall 50a extends from the annular radial wall.

[0067] The groove 50 also includes an annular side wall 50b connected to the outer cylindrical surface 12b of the inner ring. The side wall 50b extends in the radial direction. As an option, the side wall 50b can extend outwardly at an angle. The side wall 50b is connected to the tapered wall 50a. As an option, the groove can be provided with a cylindrical bottom that connects the tapered wall 50a and the side wall 50b to each other.

[0068] The first distance sensor 24 faces the groove 50 of the inner ring in the radial direction. The sensor 24 faces the tapered wall 50a of the groove. The sensor 24 measures the radial distance from the tapered wall 50a of the groove.

[0069] The outer ring 14 is provided with a first radial through hole 52, and the first distance sensor 24 is located inside the first 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 faces the groove 50 of the inner ring in the radial direction.

[0070] In the example shown, the sensor 24 is mounted in the through hole 52 and radially protrudes into the radial space provided between the outer ring 10 and the inner ring 12, and into the groove 50 of the inner ring. The sensor 24 remains spaced apart from the conical wall 50a of the groove. As an alternative, the first sensor 24 can be completely located inside the through hole 52. Preferably, the shape of the through hole 52 is complementary to that of the sensor 24.

[0071] The outer ring 10 further comprises a first plug ( / 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 (e.g., by press fit). The plug 54 is flush with the outer cylindrical surface 10b of the outer ring.

[0072] The 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. The sensor body 56 faces the groove 50 of the inner ring in the radial direction. The sensor body 56 faces the tapered wall 50a of the groove. The sensor body 56 protrudes into the groove 50 in the radial direction. The sensor body 56 is kept spaced apart from the tapered wall 50a of the groove.

[0073] In the disclosed example, the sensor 24 also includes an output connecting cable 58 for transmitting sensed data, and the output connecting cable 58 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) through which the output cable 58 can pass. The output cable 58 connects the sensor 24 to a control unit (not shown) of the rolling bearing to transmit the sensed measurement value. As an option, in the case of a wireless sensor, the sensor 24 may not have such an output cable.

[0074] The sensor body 56 of the sensor has a longitudinal axis 60 extending in the radial direction. The axis 60 also forms the longitudinal axis of the sensor 24. The axis 60 is perpendicular to the axis XX' of the rolling bearing. The axis 60 is perpendicular to the outer cylindrical surface 12b of the inner ring on which the groove 50 is formed.

[0075] The sensor 24 may be an inductive distance sensor, an ultrasonic distance sensor, or an optical distance sensor. Alternatively, the sensor 24 may be a mechanical distance sensor provided with a contact stylus. In the case of a mechanical distance sensor, the mechanical sensor faces the tapered wall 50a of the slot but also contacts the tapered wall.

[0076] The second distance sensor 25 faces radially towards the outer cylindrical surface of the nose 40 of the inner ring, which delimits the axial raceway 34. The sensor 25 measures the radial distance from the outer cylindrical surface of the nose 40.

[0077] The outer ring 14 is provided with a second radial through hole 62, and the second distance sensor 25 is located inside the second radial through hole 62. The through hole 62 extends from the outer surface 10b of the outer ring and opens on the hole 10a. The through hole 52 radially faces the outer cylindrical surface of the nose 40 of the inner ring that defines the axial raceway 34.

[0078] In the example shown, the sensor 25 is mounted in the through hole 62 and protrudes radially into the radial space provided between the nose 40 of the inner ring and the groove 38 of the outer ring. The sensor 25 remains spaced apart from the nose 40 of the inner ring. As an alternative, the second sensor 25 can be completely located inside the through hole 62. Preferably, the shape of the through hole 62 is complementary to that of the sensor 25.

[0079] The outer ring 10 further comprises a second plug 64 which closes and seals the through hole 62. The plug 64 is radially located in the through hole 62. The plug 64 is fixed inside the through hole 62 by any suitable means, such as by press fitting. The plug 64 is flush with the outer cylindrical surface 10b of the outer ring.

[0080] The sensor 25 includes a sensor body 66 mounted inside the through hole 62 of the outer ring. The sensor body 66 is fixed inside the through hole 62 by any suitable means, such as by press fitting. The sensor body 66 radially faces the outer cylindrical surface of the nose 40 of the inner ring that defines the axial raceway 34. The sensor body 66 radially protrudes into the radial space provided between the nose 40 of the inner ring and the groove 38 of the outer ring. The sensor body 66 is kept spaced apart from the nose 40.

[0081] In the disclosed example, the sensor 25 also includes an output connection cable 68 for transmitting sensed data, which extends outward relative to the sensor body 66. The output cable 68 extends outward in the radial direction. The plug 64 is provided with a through hole (not shown) that enables the output cable 68 to pass therethrough. The output cable 68 connects the sensor 25 to the control unit to transmit the sensed measurement value. As an option, in the case of a wireless sensor, the sensor 25 may not have such an output cable.

[0082] The sensor body 66 of the sensor has a longitudinal axis 70 extending in radial direction. The axis 70 also forms the longitudinal axis of the sensor 25. The axis 70 is perpendicular to the axis XX' of the rolling bearing. The axis 70 is perpendicular to the outer cylindrical surface of the nose 40 of the inner ring delimiting the axial raceway 34.

[0083] Similar to the first sensor 24 , the second sensor 25 may be an inductive distance sensor, an ultrasonic distance sensor, an optical distance sensor, or a mechanical distance sensor.

[0084] As previously described, the sensor 24 measures the radial distance from the conical wall 50a of the groove of the inner ring and the sensor 25 measures the radial distance from the outer cylindrical surface of the nose 40 of said inner ring.

[0085] Figure 2 Schematically shown above is a pure axial displacement of the inner ring 12 relative to the outer ring 10 . The groove 50 indicated by a dotted line indicates the position of the inner ring 12 after the axial displacement. The axial displacement Da of the inner ring 12 relative to the outer ring 10 is indicated by an arrow mark 72 .

[0086] Arrow 74 indicates a first radial distance from the tapered wall 50a of the groove measured by the sensor 24 before the inner ring 12 is displaced relative to the outer ring 10. A second radial distance from the tapered wall 50a of the groove measured by the sensor 24 after the axial displacement is indicated by arrow 76.

[0087] ΔM indicated by arrow mark 78 represents the radial displacement of the tapered wall 50a of the groove relative to the outer ring 10 detected by the sensor 24. The value of the relative radial displacement ΔM is equal to the difference between the second radial distance measured by the sensor 24 and the first radial distance, i.e. the differential measurement of the sensor 24.

[0088] In such Figure 2 In the case of pure axial displacement of the inner ring 12 relative to the outer ring 10 shown above, the value of the radial displacement ΔM of the tapered wall 50a of the groove relative to the outer ring 10 is also equal to:

[0089] ΔM=Da×sinα, where Da is the value of the axial displacement of the inner ring 12 relative to the outer ring 10, and α is the value of the angle of the tapered wall 50a of the groove.

[0090] In the case of a combination of axial and radial displacements of the inner ring 12 relative to the outer ring 10, the value of the radial displacement ΔM of the tapered wall 50a of the groove relative to the outer ring 10 is equal to:

[0091] ΔM=(Da×sinα)+Dr, where Dr is the value of the radial displacement of the outer cylindrical surface of the nose 40 of the inner ring relative to the outer ring 10 detected by the second sensor 25. Before the displacement of the inner ring 12 relative to the outer ring 10, a first radial distance from the outer cylindrical surface of the nose 40 is measured by the sensor 25. However, after the displacement, a second radial distance from the outer cylindrical surface of the nose 40 is measured by the sensor 25. The value of the relative radial distance Dr is equal to the difference between the second radial distance measured by the sensor 25 and the first radial distance, i.e., the differential measurement of the sensor 25.

[0092] Therefore, the value of the axial displacement Da of the inner ring 12 relative to the outer ring 10 is equal to:

[0093] Thus, the axial displacements of the tapered groove 50 of the inner ring 12 (and more generally the inner ring 12) relative to the outer ring 10 can be calculated from the radial displacements measured by the sensors 24, 25. Advantageously, the control unit of the rolling bearing calculates these axial displacements of the inner ring 12 relative to the outer ring 10.

[0094] Furthermore, the measurements performed by the sensor 25 can be used by the control unit to determine the radial play of the rolling bearing.

[0095] In the example shown, the rolling bearing further comprises an additional seal 80 arranged inside the closed space 46 defined by the seals 42, 44. The seal 80 is located axially near the seal 42. The seal 80 is axially arranged between the seal 42 and the row of axial rollers 20. In the example shown, the seal 80 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 80 is in contact with the hole 10a of the outer ring near the through hole 52. As an option, the seal 80 can be mounted on the outer ring 14 and in frictional contact with the inner ring 12.

[0096] The seal 80 defines a closed detection space (not shown) together with the seal 42 between the outer ring 10 and the inner ring 12 in the radial direction, and the interior of the detection space leads to the groove 50 of the inner ring and the through hole 52 of the outer ring. Only the groove 50, the through hole 52 and the sensor 24 are located inside the detection space. There is no roller row inside the detection space. This reduces the risk of contaminants such as grease, dust and water reaching the sensor 24.

[0097] In the example shown, the tapered 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. Alternatively, the groove 50 may be provided on another region of the outer cylindrical surface 12b depending on the design of the rolling bearing.

[0098] In another variant, the opposite configuration between sensors 24, 25 can also be foreseen, with groove 50 being provided on the outer cylindrical surface of nose 40 of the inner ring on which axial raceway 34 is formed. In this case, sensor 24 is axially located between the row of radial rollers 22 and the row of axial rollers 20 or 18.

[0099] In another variant, depending on the design of the rolling bearing, the sensor 25 can also be arranged in front of the outer axial cylindrical surface of the inner ring on which the tapered groove 50 is formed.

[0100] Furthermore, as previously mentioned, in the illustrated example, the first ring of the rolling bearing is the outer ring 10 and the second ring is the inner ring 12 .

[0101] 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 tapered 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 bore of said outer ring, and the sensors 24, 25 are mounted on the inner ring.

[0102] In the example described, the rolling bearing is provided with three rows of rolling elements. As an alternative, the rolling bearing may comprise 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 comprise 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 tapered groove (50) is formed on the first axial cylindrical surface (12b) of the second ring and is oriented toward the first ring (10), the bearing further comprising: - at least one first distance sensor (24) mounted on the first ring and facing the conical wall (50a) of the conical groove of the second ring, the conical wall (50a) being inclined relative to the axis (XX') of the bearing, the longitudinal axis (60) of the first distance sensor (24) being perpendicular to the axis (XX'), and at least one second distance sensor (25), mounted on said first ring and different from said first distance sensor (24), said second distance sensor (25) radially facing a second axial cylindrical surface of said second ring, The bearing further comprises a control unit connected to the first distance sensor (24) and the second distance sensor (25) and adapted to calculate a value of a relative axial displacement (Da) between the first ring and the second ring based on the following formula: in, -ΔM is the value of the differential measurement of the first distance sensor (24) on the conical wall (50a) of the second ring, - Dr is the value of the relative radial displacement between the first circle and the second circle detected by the second distance sensor (25), and - α is the value of the angle formed in a radial plane of the bearing between the tapered wall (50a) of the tapered groove and the first axial cylindrical surface (12b) of the second ring.

2. The bearing according to claim 1, characterized in that: The second circle of tapered grooves (50) are annular.

3. The bearing according to claim 1 or 2, characterized in that: The first ring (10) comprises at least a first through hole (52) and a second through hole (62), the first distance sensor (24) is at least partially arranged in the first through hole (52), and the second distance sensor (25) is at least partially arranged in the second through hole (62).

4. The bearing according to claim 3, characterized in that: Each through hole (52, 62) 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, which radially faces the second ring.

5. The bearing according to claim 1 or 2, characterized in that: The first axial cylindrical surface (12b) of the second ring is offset from the second axial cylindrical surface in the radial direction.

6. The bearing according to claim 1 or 2, characterized in that: The bearing further comprises at least one row of rolling elements (18; 22) arranged between raceways (28, 26; 36, 34) provided on the first ring and the second ring.

7. 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 (28, 26) provided on the first ring and the second ring and at least one row of radial rolling elements (22) arranged between axial raceways (36, 34) 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 the second axial cylindrical surface, the axial raceway (34) of the second ring being formed onto the second axial cylindrical surface.

8. The bearing according to claim 7, characterized in that The nose (40) protrudes radially from the first axial cylindrical surface (12b) of the second ring where the tapered groove (50) is formed.

9. The bearing according to claim 1 or 2, characterized in that: Each of the first distance sensor (24) and the second distance sensor (25) is a proximity sensor.

10. The bearing according to claim 9, characterized in that The proximity sensor is an inductive sensor, an ultrasonic sensor, or an optical sensor.

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