Bearing with a distance measurement system and an associated groove

Abstract

The bearing includes a first ring (10) and a second ring (12) that are capable of rotating concentrically relative to each other. At least one annular groove (50) is formed in the second ring (12) and is oriented towards the first ring (10). The bearing further includes at least one measurement system (24). The at least one measurement system (24) is mounted on the first ring (10) and includes: at least one guide rail (56); at least one carriage (58) that is mounted on the guide rail and is capable of moving axially relative to the guide rail; at least one sensor for detecting the axial position of the carriage relative to the guide rail; a contact element (60) that is attached to the carriage (58) and contacts at least one wall (50a) of the groove of the second ring at least in the axial direction; and a prestressing element (62) for maintaining the contact between the contact element (60) and the wall (50a) of the groove.

Description

Field of the Invention

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

[0002] In particular, the present invention relates to the field of large-diameter rolling bearings which are capable of accommodating axial and radial loads and which have an inner ring and an outer ring which are concentrically arranged about a rotational 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] The large-diameter rolling bearing comprises 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 generally loaded both axially and radially and are often loaded 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 the rolling elements leads to a significant increase in the initial bearing clearance. Wear beyond a certain value can lead to serious bearing failures.

[0006] Measuring the wear of the bearing by means of the increase in clearance (which causes relative axial and radial displacements of the rings) helps to predict the remaining life of the bearing.

[0007] This unwanted movement affects the correct functioning of the bearing and the application and there is a risk of contact and collision of the bearing rings. Other elements attached to the bearing rings may also collide.

[0008] It is common to replace the bearing when it is worn. Such maintenance interventions are expensive, especially since the machine or installation needs to be shut down. It is therefore desirable to carry out such maintenance interventions in good time before any contact occurs between the bearing rings, but not too early either.

[0009] In order to monitor the condition of the bearing 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. Thereby, the axial relative movement and the angular relative movement between the inner ring and the outer ring can be detected.

[0010] However, this requires mounting the annular magnetic target on the inner ring which can have a diameter of several metres.

[0011] Reference may also be made to the rolling bearing disclosed in patent US-B2-10041545 and including an encoder provided with a magnetic strip portion attached in a flat manner against the outer ring and cooperating with a sensor fixed to the inner ring.

[0012] However, with this configuration, it is not possible to measure the axial relative movement between the inner and outer rings without taking into account the rotational position of the rings, and the axial relative movement between the inner and outer rings can only be measured when the outer ring is in the rotational position where the magnetic strip portion is in front of the sensor of the inner ring.

[0013] In addition, in the case of using such a magnetic target as disclosed in the above document, 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 the magnetic target, the air gap between the target and the sensor varies with the radial relative movement between the rings, resulting in a reduction in measurement accuracy or even making it impossible to measure. SUMMARY OF THE INVENTION

[0014] An object of the present invention is to overcome these drawbacks.

[0015] The present invention relates to a bearing comprising a first ring and a second ring capable of rotating concentrically relative to each other.

[0016] According to a general feature, at least one annular groove is formed in the second ring and is oriented towards the first ring.

[0017] According to another general feature, the bearing further comprises at least one measurement system mounted on the first ring and comprising:

[0018] - at least one guideway;

[0019] - at least one sliding carriage mounted on the guideway and capable of moving axially relative to the guideway;

[0020] - at least one sensor arranged on one of the sliding carriage and the guideway and adapted to detect the axial position of the sliding carriage relative to the guideway;

[0021] - a contact element attached to the sliding carriage and contacting at least one wall of the groove of the second ring at least in the axial direction; and

[0022] - a pre-stressing element for maintaining the contact between the contact element and the wall of the groove.

[0023] The prestressing element applies a permanent force to ensure the contact of the abutting element with the wall of the groove.

[0024] The wall of the groove can be the side wall of the groove or any other wall or part inclined with respect to the axis of the bearing.

[0025] Thanks to the present invention, the axial relative displacement between the rings (first ring and second ring) can be precisely detected regardless of the rotational position of the rings. In fact, the axial position of the carriage moving axially together with the abutting element in contact with the groove of the second ring is detected by a 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.

[0026] Advantageously, the first ring includes a radial hole facing the groove of the second ring in the radial direction, and the measuring system is partially arranged in the radial hole. The hole can extend radially from the axial cylindrical surface of the first ring facing the second ring and open on the opposite axial cylindrical surface located on the side opposite to the second ring in the radial direction. Thus, the measuring system is inserted into the through hole (i.e., the radial hole) in a simple manner and configured in its final position. The first ring can also include a plug for sealing the hole.

[0027] In one embodiment, the guide rail of the measuring system is fixed to the first ring. In this case, the prestressing element can be arranged axially between the guide rail and the carriage.

[0028] In an alternative embodiment, the measuring system can include:

[0029] - a first guide rail and a first carriage, the first guide rail being fixed to the first ring, the first carriage being mounted on the first guide rail and capable of moving radially relative to the first guide rail,

[0030] - a first sensor arranged on one of the first carriage and the first guide rail and adapted to detect the radial position of the first carriage relative to the first guide rail,

[0031] - a second guide rail and a second carriage, the second guide rail being fixed to the first carriage, the second carriage being mounted on the second guide rail and capable of moving axially relative to the second guide rail, and

[0032] - a second sensor arranged on one of the second carriage and the second guide rail and adapted to detect the axial position of the second carriage relative to the second guide rail,

[0033] - the abutting element is attached to the second carriage.

[0034] In this embodiment, the axial relative displacement between the first ring and the second ring can be detected by using the second carriage to support the axial position of the abutting element. In addition, the radial relative displacement between the first ring and the second ring can be detected by using the first carriage to support the radial position of the second carriage.

[0035] The prestressing element can be arranged radially between the first guide rail and the first carriage.

[0036] In this embodiment, the abutting element can include tapered rollers that engage into grooves in the second ring, and the grooves have a complementary tapered shape.

[0037] In one embodiment, the bearing further includes at least one row of rolling elements disposed between raceways provided on the first ring and the second ring.

[0038] The bearing may further include a first seal and a second seal, which are arranged between the first ring and the second ring and together define a closed rolling space, and the row of rolling elements and at least a part of the measuring system are accommodated inside the closed rolling space.

[0039] In one embodiment, the bearing may further include at least one additional seal, which is located inside the closed rolling space and together with one of the first seal and the second seal defines a closed detection space, and the inside of the closed detection space leads to the groove.

[0040] In one embodiment, the bearing includes at least one row of axial rolling elements disposed between radial raceways provided on the first ring and the second ring and at least one row of radial rolling elements disposed between axial raceways provided on the first ring and the second ring, the second ring includes a protruding nose that engages into an annular groove in the first ring and protrudes radially from the axial cylindrical surface of the second ring, and the groove is formed on the axial cylindrical surface.

[0041] The term "axial rolling element" is understood to mean a rolling element adapted to accommodate axial loads, while the term "radial rolling element" is understood to mean a rolling element adapted to accommodate radial loads.

[0042] The nose of the second ring may also be provided with two opposed radial sides (flanks) that axially delimit the axial cylindrical surface, with at least one of the radial sides at least partially delimiting the radial raceway of the second ring.

[0043] In one embodiment, the bearing includes at least two rows of axial rolling elements respectively disposed between the 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.

[0044] In one embodiment, the (plural) sensors may be proximity sensors, in particular inductive sensors, ultrasonic sensors or optical sensors. Description of the Drawings

[0045] The invention and its advantages will be better understood from the detailed description of specific embodiments given by way of non-limiting example and illustrated in the drawings, in which:

[0046] - Figure 1 is a partial cross-section of a rolling bearing according to a first example of the invention, and

[0047] - Figure 2 is a partial cross-section of a rolling bearing according to a second example of the invention. Detailed Description of the Invention

[0048] As Figure 1 The illustrated rolling bearing is a large-diameter rolling bearing including a first ring 10 and a second ring 12. In the illustrated example, the first ring 10 is an outer ring, and the second ring 12 is an inner ring. The rolling bearing may be used, for example, in a tunnel boring machine, a wind turbine or any other application using a large-diameter rolling bearing.

[0049] The outer ring 10 and the inner ring 12 are concentric and extend axially along a bearing rotation axis X-X' extending in the axial direction. The rings 10, 12 are of solid type.

[0050] The outer ring 10 is formed as a split ring and includes a first ring 14 and a second ring 16 stacked axially relative to each other. 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.

[0051] In the illustrated example, the rolling bearing includes two rows of axial rollers 18, 20 disposed between the outer ring 10 and the inner ring 12 to form an axial thrust, and one row of radial rollers 22 disposed between the outer ring 10 and the inner ring 12 to form a radial thrust.

[0052] As will be described later, the rolling bearing further includes a measurement system 24 for detecting the axial relative displacement between the outer ring 10 and the inner ring 12. In the illustrated example, the measurement system 24 is mounted on the outer ring 10.

[0053] The rollers 18, 20, 22 in a row are identical to each other. Each roller 18, 20, 22 includes a cylindrical outer rolling surface and two opposite front surfaces defining the outer rolling surface. The axis of rotation of each roller 22 is parallel to the axis X-X' of the bearing and perpendicular to the axes of each roller 18, 20. In the illustrated example, 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.

[0054] The roller 18 is axially disposed between annular radial raceways 26, 28 respectively formed 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 roller 18. The raceways 26, 28 face each other in the axial direction.

[0055] The roller 20 is axially disposed between annular radial raceways 30, 32 respectively formed on the inner ring 12 and the outer ring 10. 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 the rollers 18, 20 are spaced apart from each other in the axial direction.

[0056] The roller 22 is radially disposed between annular axial raceways 34, 36 respectively formed on the inner ring 12 and the outer ring 10. 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 the rollers 22 is radially offset (outward) relative to the rows of the rollers 18, 20. The row of the rollers 22 is axially located between the row of the rollers 18 and the row of the rollers 20.

[0057] The outer ring 10 includes an annular groove 38 that opens inward in the radial direction towards the inner ring 12. The outer ring 10 includes a stepped inner cylindrical surface or bore 10a, and the groove 38 is formed by the stepped inner cylindrical surface or bore 10a. The outer ring 10 further includes an outer cylindrical surface 10b that is radially opposite (back-to-back) to the bore 10a. The outer ring 10 further includes two opposite radial front surfaces 10c, 10d, and the radial front surfaces 10c, 10d axially define the bore 10a and the outer surface 10b of the ring.

[0058] The inner ring 12 includes an annular protruding nose portion 40 that engages into the annular groove 38 of the outer ring. The nose portion 40 extends radially outward.

[0059] The inner ring 12 includes an inner cylindrical bore 12a and a stepped outer cylindrical surface 12b that is radially opposite the bore 12a. In the illustrated example, the bore 12a of the inner ring is provided with gear teeth (not shown). The inner ring 12 also includes two opposed radial front surfaces 12c, 12d that axially delimit the bore 12a and the outer cylindrical surface 12b. A projecting nose 40 projects radially from the outer cylindrical surface 12b.

[0060] The rows of rollers 18, 20 are axially disposed 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. Alternatively, the radial raceway 26 may be entirely 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.

[0061] More precisely, the first radial side (flank) of the nose 40 partially delimits the radial raceway 26 for the roller 18. The first radial side of the groove 38 that axially faces the first radial side of the nose 40 delimits the radial raceway 28 for the roller 18. The second side of the nose 40 and the facing second side of the groove 38 respectively delimit the radial raceways 30, 32 for the roller 20. The opposed first and second sides of the nose 40 axially delimit the nose. Similarly, the opposite first and second sides of the groove 38 axially delimit the groove. Each of the first and second sides of the nose 40 extends radially from the outer cylindrical surface 12b of the inner ring.

[0062] The row of rollers 22 is radially disposed between the nose 40 of the inner ring and the groove 38 of the outer ring. The axial raceways 34, 36 are respectively located on the nose 40 and the groove 38. The outer cylindrical surface of the nose 40 delimits the axial raceway 34. The outer cylindrical surface of the nose 40 and the outer cylindrical surface 12b are radially offset. As a result, the axial raceway 34 and the outer cylindrical surface 12b are also radially offset. The outer cylindrical surface of the nose 40 extends axially between the opposed radial sides of the nose.

[0063] The axial bottom of the groove 38 delimits the axial raceway 36. In the illustrated example, an annular slot 41 is formed in the bottom of the groove 38 and delimits 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.

[0064] In the example shown, the inner ring 12 is made as a single piece. As an alternative, the inner ring 12 can be divided in the axial direction into at least two separate parts that are fixed together. In another variant, the nose 40 can be manufactured separately from the main part of the inner ring.

[0065] As previously mentioned, the outer ring 10 is divided in the axial direction into two separate parts, 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.

[0066] The rolling bearing also includes annular seals 42, 44 on both sides. The annular seals 42, 44 are mounted on the inner ring 12 and are arranged to enclose 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.

[0067] A closed space 46 is defined between the inner ring 12 and the outer ring 14 and the seals 42, 44. The rows of rolling elements 18, 20, and 22 and the measuring system 24 are accommodated in the closed space 46.

[0068] Each of the seals 42, 44 is mounted in a groove (not labeled) formed in 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 bore 10a of the outer ring axially near the row of rollers 18. As an alternative, at least one of the seals 42, 44 can be provided with the opposite configuration, such that the seal is mounted on the outer ring 10 and makes frictional contact with the inner ring 12.

[0069] As previously mentioned, the measuring system 24 is arranged to detect the axial relative displacement between the outer ring 10 and the inner ring 12. For this purpose, an annular groove 50 is also formed on the inner ring 12.

[0070] In the example shown, the groove 50 is formed on the outer cylindrical surface 12b of the inner ring. The groove 50 extends radially inward from the outer cylindrical surface 12b. The groove 50 is bounded axially by two annular side edges or side walls 50a, 50b. The side walls 50a, 50b face each other axially. The side walls 50a, 50b are spaced apart from each other axially. The groove 50 also includes an annular bottom 50c connected to the side walls 50a, 50b. The outer cylindrical surface 12b of the inner ring and the bottom 50c of the groove are offset radially.

[0071] In the example shown, the side walls 50a, 50b of the groove extend radially, and the bottom 50c extends axially. The groove 50 has a rectangular cross-section. As an alternative, the groove can include an annular tapered bottom connected to the side walls.

[0072] The outer ring 10 is provided with radial through-holes (radial holes) 52, and the measuring system 24 is located within the radial through-holes 52. The through-holes 52 extend from the hole 10a of the outer ring and open on the outer surface 10b. The through-holes 52 face the groove 50 of the inner ring in the radial direction.

[0073] The outer ring 10 further includes a plug 54, which closes and seals the through-hole 52. The plug 54 is located within the through-hole 52 in the radial direction. 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.

[0074] The measuring system 24 includes a guideway 56 fixed to the outer ring 10, a carriage 58 slidably mounted axially on the guideway, and a sensor (not visible) for detecting the axial position of the carriage 58 relative to the guideway 56.

[0075] The sensor is integrated into the carriage 58. The sensor can be an optical sensor. The guideway 56 has tracks encoded in the axial direction and oriented towards the sensor. The tracks can be encoded with continuous markings in the axial direction, such as the tracks can be incremental tracks. As an alternative, the opposite arrangement where the sensor is on the guideway 56 and the tracks are on the carriage 58 can be envisaged. The sensor is connected to the control unit (not shown) of the rolling bearing to transmit the sensed measurement values.

[0076] The measuring system 24 further includes a contact stylus 60 fixed to the carriage 58. The stylus 60 can be fixed to the carriage 58 by any suitable means.

[0077] The stylus 60 projects radially into the groove 50 of the inner ring. The stylus 60 extends from the carriage 58 and is partially located within the hole 52 of the outer ring. The stylus 60 extends radially inwards. The stylus 60 contacts the side wall 50a of the groove axially. In the illustrated example, the stylus 60 is provided with a rounded free end to reduce friction with the inner ring 12 when the inner ring 12 rotates. As an alternative, the stylus 60 can have other shapes to contact the side wall 50a of the groove axially.

[0078] The measuring system 24 further includes a spring 62 to always maintain axial contact between the stylus 60 and the side wall 50a of the groove.

[0079] In this example, the spring 62 is axially interposed between the carrier 58 and the guide rail 56. The spring 62 applies an axially prestressed permanent force on the carrier 58 to ensure constant contact between the stylus 60 and the side wall 50a of the groove. The spring 62 serves as a prestressing element. The first end of the spring 62 bears against the guide rail 56, and the opposite second end bears against the carrier 58. In the illustrated example, the spring 62 is a compression spring. As an alternative, other prestressing elements can be provided to apply a permanent force on the carrier 58. For example, the other prestressing elements are elastic washers, such as Belleville washers.

[0080] The guide rail 56 is fixed inside the through-hole 52 by any suitable means (such as by press-fitting). The guide rail 56 can be fixed to the hole 52 or the plug 54. The guide rail 56 is completely located within the hole 52.

[0081] The carrier 58 is located within the through-hole 52 of the outer ring. The carrier 58 is slidably mounted on the guide rail 60 in the axial direction. For example, the carrier 58 and the guide rail 60 can have the same construction type as that of the Minislide MSQ measuring system commercialized by Schneeberger.

[0082] When the inner ring 12 undergoes an axial displacement relative to the outer ring, this causes a corresponding axial displacement of the stylus 60 of the measuring system. The carrier 58 moves axially together with the stylus 60 relative to the guide rail 56. The axial displacement of the carrier 58 is detected by an integrated sensor.

[0083] The control unit connected to the sensor of the measuring system 24 calculates the corresponding value of the axial displacement of the inner ring 12 relative to the outer ring 10.

[0084] In the illustrated example, the rolling bearing further includes an additional seal 66 disposed inside the enclosed space 46 defined by the seals 42, 44. The seal 66 is axially located near the seal 42. The seal 66 is axially arranged between the seal 42 and the row of axial rollers 20. In the illustrated example, the seal 66 is mounted in a groove (not labeled) formed on the outer cylindrical surface 12b of the inner ring and contacts the outer ring 10. The seal 66 contacts the hole 10a of the outer ring near the hole 52. As an alternative, the seal 66 can be mounted on the outer ring 14 and in frictional contact with the inner ring 12.

[0085] The seal 66 together with the seal 42 radially defines an enclosed detection space (not labeled) between the outer ring 10 and the inner ring 12. The interior of the detection space leads to the groove 50 of the inner ring and the hole 52 of the outer ring. Only the groove 50, the hole 52, and the measuring system 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 of the measuring system 24.

[0086] In Figure 2 the example shown, where like parts are given like reference numerals, the measurement system 24 is designed differently from the measurement system of the first example.

[0087] The measurement system 24 includes a first guide rail 70 fixed to the outer ring 10, a first carriage 72 slidably mounted radially on the first guide rail, and a first sensor (not visible) for detecting the radial position of the carriage 72 relative to the guide rail 70. As described in the first example, the sensor is integrated into the carriage 72 or the guide rail 70. The guide rail 70 is fixed inside the through-hole 52 of the outer ring. The guide rail 70 can be fixed to the hole 52 or the plug 54. The carriage 72 is slidably mounted on the guide rail 70 in the radial direction.

[0088] The measurement system 24 further includes a second guide rail 74, a second carriage 76 slidably mounted axially on the second guide rail, and a second sensor (not visible) for detecting the axial position of the carriage 76 relative to the guide rail 74. The second guide rail 74 is fixed to the first carriage 72. The carriage 76 is slidably mounted on the second guide rail 74 in the axial direction.

[0089] The measurement system 24 further includes a contact roller 78 attached to the second carriage 76. The measurement system 24 further includes a bearing 80 for attaching the roller 78 to the carriage 76.

[0090] The rotational axis of the roller 78 extends axially, i.e., parallel to the axis X-X' of the bearing. The roller 78 is partially located within the hole 52 of the outer ring. The roller 78 projects radially into the groove 50 of the inner ring. The outer surface of the roller has a conical shape complementary to the groove 50.

[0091] In this example, the groove 50 has a V-shaped cross-section. The side walls 50a, 50b of the groove extend obliquely. In this example, the conical groove 50 does not have a cylindrical bottom. As an alternative, the groove 50 can be provided with a cylindrical bottom. The roller 78 contacts the side walls 50a, 50b of the groove in the axial direction and in the radial direction.

[0092] The measurement system 24 further includes a spring 82 to always maintain contact between the roller 78 and the side walls 50a, 50b of the groove in the axial direction and in the radial direction. In this example, the spring 82 is radially interposed between the first guide rail 70 and the first carriage 72.

[0093] The spring 82 applies a radially prestressing permanent force to the carriage 72 to ensure a constant contact between the roller 78 and the side walls 50a, 50b of the groove. The spring 82 serves as a prestressing element. The first end of the spring 82 bears against the guideway 70, and the opposite second end bears against the carriage 72. In the example shown, the spring 82 is a compression spring. As an alternative, other prestressing elements can be provided to apply a permanent force to the carriage 72. For example, the other prestressing elements are elastic washers, such as Belleville washers.

[0094] When the inner ring 12 undergoes an axial displacement relative to the outer ring, this causes a corresponding axial displacement of the roller 78 and the second carriage 76 of the measuring system relative to the second guideway 74, which is detected by the second sensor.

[0095] When the inner ring 12 undergoes a radial displacement relative to the outer ring, this causes a corresponding radial displacement of the roller 78, the second carriage 76, the second guideway 74, and the first carriage 72 of the measuring system relative to the first guideway 70. The radial displacement of the first carriage 72 relative to the first guideway 70 is detected by the first sensor.

[0096] In the example shown, the groove 50 is formed on the outer cylindrical surface 12b of the inner ring that is axially located between the row of axial rollers 20 and the seal 42. As an alternative, depending on the design of the rolling bearing, the groove 50 can be provided in another area of the outer cylindrical surface 12b, or on the outer cylindrical surface of the nose 40 of the inner ring where the axial raceway 34 is formed. In this latter case, the measuring system 24 is axially located between the row of radial rollers 22 and the row of axial rollers 20 or 18.

[0097] Alternatively, as previously described, in these shown examples, the first ring of the rolling bearing is the outer ring 10, and the second ring is the inner ring 12.

[0098] As an alternative, a reverse configuration can be provided, such that the first ring forms the inner ring and the second ring forms the outer ring. In this case, the groove 50 is formed on the axial inner cylindrical surface of the outer ring, the axial inner cylindrical surface of the outer ring forms the bore of the outer ring, and the measuring system 24 is mounted on the inner ring.

[0099] In the example described, the rolling bearing is provided with three rows of rolling elements. As an alternative, the rolling bearing can 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 can include other types of rolling elements, such as balls. In another variant, the bearing can also be a sliding bearing without rolling elements.

Claims

1. A bearing, comprising a first ring (10) and a second ring (12) that can rotate concentrically relative to each other, characterized in that, at least one annular groove (50) is formed in the second ring (12) and is oriented towards the first ring (10), and the bearing further comprises at least one measurement system (24), the at least one measurement system (24) being mounted on the first ring (10) and comprising: - at least one guide rail (56; 74); - at least one carriage (58; 76), mounted on the guide rail and capable of moving axially relative to the guide rail; - at least one sensor, arranged on one of the carriage and the guide rail and adapted to detect the axial position of the carriage relative to the guide rail; - a contact element (60; 78), attached to the carriage (58; 76) and in contact with at least one wall (50a) of the groove of the second ring at least in the axial direction; and - a prestressing element (62; 82) for maintaining the contact between the contact element (60; 78) and the wall (50a) of the groove.

2. The bearing according to claim 1, characterized in that, the first ring (10) comprises a radial hole (52) that faces the groove (50) of the second ring in the radial direction, and the measurement system (24) is partially arranged in the radial hole (52).

3. The bearing according to claim 2, characterized in that, the hole (52) of the first ring extends in the radial direction from an axial cylindrical surface (10a) of the first ring that faces the second ring in the radial direction and opens on an opposite axial cylindrical surface (10b) that is located on the side opposite to the second ring in the radial direction.

4. The bearing according to any one of claims 1 to 3, characterized in that, the guide rail (56) of the measurement system is fixed to the first ring (10).

5. The bearing according to claim 4, characterized in that, the prestressing element (62) is arranged axially between the guide rail (56) and the carriage (58).

6. The bearing according to any one of claims 1 to 3, characterized in that, the measurement system (24) comprises: - a first guide rail (70) and a first carriage (72), the first guide rail (70) being fixed to the first ring (10), the first carriage (72) being mounted on the first guide rail and capable of moving radially relative to the first guide rail, - a first sensor, arranged on one of the first carriage and the first guide rail and adapted to detect the radial position of the first carriage relative to the first guide rail, - a second guide rail (74) and a second carriage (76), the second guide rail (74) being fixed to the first carriage (72), the second carriage (76) being mounted on the second guide rail and capable of moving axially relative to the second guide rail, and - a second sensor, arranged on one of the second carriage and the second guide rail and adapted to detect the axial position of the second carriage relative to the second guide rail, - The abutting element (78) is attached to the second carriage (76).

7. The bearing according to claim 6, wherein, the prestressing element (82) is arranged radially between the first guide rail (70) and the first carriage (72).

8. The bearing according to claim 6, wherein, the abutting element comprises tapered rollers (78), the tapered rollers (78) being engaged in the grooves (50) of the second ring, and the grooves having a complementary tapered shape.

9. The bearing according to any one of claims 1 to 3, wherein, the bearing further comprises at least one row of rolling elements (18; 22) disposed between the raceways (28, 26; 36, 34) provided on the first ring and the second ring.

10. The bearing according to any one of claims 1 to 3, wherein, the bearing comprises at least one row of axial rolling elements (18) disposed between the radial raceways (28, 26) provided on the first ring and the second ring and at least one row of radial rolling elements (22) disposed between the axial raceways (36, 34) provided on the first ring and the second ring, the second ring (12) including a protruding nose portion (40), the protruding nose portion (40) being engaged in the annular groove (38) of the first ring and protruding radially from the axial cylindrical surface (12b) of the second ring, and the groove (50) being formed in the axial cylindrical surface (12b).

Images