Rolling bearing, in particular large-diameter rolling bearing

Abstract

A rolling bearing comprises a first ring (10), a second ring (12), at least one row of radial rolling elements (22) interposed radially between axial raceways (38, 40) of the rings, at least one row of axial rolling elements (20) interposed axially between radial raceways (30, 32) of the rings and located radially between axial guide surfaces (34, 36) of the rings, and at least one segmented cage (50) for retaining the row of axial rolling elements and comprising a plurality of successive circumferential cage segments (52). Each of the cage segments is provided with at least two cavities (54), each cavity receiving at least one axial rolling element. The rolling bearing further comprises at least one radial rolling element (24) interposed circumferentially between two adjacent ones of the segmented cage segments, the radial rolling element being interposed radially between the axial guide surfaces of the rings.

Description

TECHNICAL FIELD

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

[0002] The present invention relates in particular to the field of large-diameter rolling bearings, which can accommodate axial and radial loads and which have an inner ring and an outer ring arranged concentrically around an axis of rotation extending in an axial direction. BACKGROUND

[0003] Such large-diameter rolling bearings can be used, for example, in a tunnel boring machine, a mining extraction machine, a large offshore crane or a wind turbine.

[0004] Large-diameter rolling bearings generally comprise two concentric inner and outer rings and a bearing assembly comprising two rows of axial rollers and one row of radial rollers. Generally, such rolling bearings are subjected to loads both in the axial and radial directions, such rolling bearings often having a relatively strong load.

[0005] Depending on the use of the roller bearing, considerable forces can be generated, which can cause deformation of the bearing, in particular of the rotating ring, in some cases leading to partial separation of the rings. Indeed, a radial gap can be created between the rotating ring and the fixed ring of the roller bearing.

[0006] To overcome this drawback, the rolling bearing disclosed in patent EP-B1-2092204 comprises two opposite rows of radial cylindrical rollers and two opposite rows of axial cylindrical rollers, arranged in the manner of a nose ring around the rotating ring.

[0007] However, the radial dimension of such a roller bearing requires a considerable installation space. In addition, the installation of four rows of cylindrical rollers also requires a large number of assembly steps. SUMMARY

[0008] One object of the present invention is to overcome these drawbacks.

[0009] The present invention relates to a rolling bearing comprising a first ring, a second ring, at least one row of radial rolling elements interposed in the radial direction between the axial raceways of the rings, at least one row of axial rolling elements interposed in the axial direction between the radial raceways of the rings and radially between the axial guide surfaces of the rings.

[0010] According to a first general feature, the rolling bearing further comprises at least one segmented cage for holding the axial rolling elements in a row and comprising a plurality of successive circumferential cage segments. Each of the cage segments is provided with at least two pockets, each pocket receiving at least one axial rolling element.

[0011] According to a second general feature, the rolling bearing further comprises at least one radial rolling element interposed circumferentially between two adjacent cage segments of the segmented cage, the radial rolling element being interposed radially between the axial guide faces of the rings.

[0012] The term "axial rolling element" is understood to mean a rolling element adapted to accommodate only axial loads, while the term "radial rolling element" is understood to mean a rolling element adapted to accommodate only radial loads.

[0013] With this configuration of the at least one radial rolling element, the radial deformation of the rolling bearing and the clearance opening in the radial direction between the inner ring and the outer ring are limited.

[0014] Two functions are achieved in the row with both the radial rolling elements and the axial rolling elements.

[0015] In addition, with respect to a conventional rolling bearing comprising two rows of radial cylindrical rollers, the number of components used to form the rings is limited by the new design of the rolling bearing. The installation space required is reduced and the design of the rolling bearing is compact. The number of assembly steps is also reduced.

[0016] Preferably, the rolling bearing comprises one radial rolling element interposed circumferentially between each end of each cage segment of the segmented cage and the facing end of an adjacent cage segment. Thus, the rolling bearing is able to withstand high radial loads and high tilting moments.

[0017] Alternatively, the rolling bearing can comprise radial rolling elements interposed circumferentially between some adjacent cage segments of the segmented cage, the other cage segments of the cage abutting one another in the circumferential direction with respect to one another.

[0018] In one embodiment, each cage segment of the segmented cage comprises two abutment ends delimiting the cage segment in the circumferential direction, and each abutment end comprises an outer abutment face, the radial rolling element abutting the facing abutment faces of two adjacent cage segments in the circumferential direction.

[0019] The outer abutment face of each cage segment of the segmented cage can have a flat form. Alternatively, the outer abutment face of each cage segment of the segmented cage can have a concave form.

[0020] The second ring can comprise a protruding nose which engages into an annular groove of the first ring and is provided with an axial cylindrical surface on which an axial raceway of the second ring is formed.

[0021] In one embodiment, the rolling bearing further comprises at least one additional row of axial rolling elements interposed axially between the radial raceway of the first ring and the radial raceway of the second ring. The row of axial rolling elements and the additional row of axial rolling elements can be arranged axially on both sides of the protruding nose of the second ring.

[0022] The row of axial rolling elements and the row of radial rolling elements can comprise cylindrical rollers. BRIEF DESCRIPTION OF DRAWINGS

[0023] The application and its advantages will be better understood through a detailed description of specific embodiments given by way of non-limiting example and illustrated by the attached drawings in which:

[0024] - Figure 1 and Figure 2 is a partial section of a rolling bearing according to an example of the application,

[0025] - Figure 3 is Figure 1 and Figure 2 is a partial perspective view of a segmented cage and rollers of the rolling bearing of

[0026] - Figure 4 is Figure 3 is a perspective view of a cage segment of the segmented cage, and

[0027] - Figure 5 is a perspective view of a cage segment of the segmented cage according to another example of the application. DETAILED DESCRIPTION

[0028] As Figure 1 illustrated, the rolling bearing is a large-diameter rolling bearing comprising a first ring 10 and a second ring 12. In the example illustrated, the first ring 10 is an inner ring and the second ring 12 is an outer ring. In this example, the outer ring 12 is the rotating ring and the inner ring 10 is the non-rotating ring. The rolling bearing can for example be used in a tunnel boring machine, a wind turbine, a large offshore crane or any other application using large-diameter rolling bearings.

[0029] The inner ring 10 and the outer ring 12 are concentric and extend in an axial direction along a bearing rotation axis (not shown). The rings 10, 12 are of a solid type.

[0030] The inner ring 10 is formed as a split ring and comprises a first ring 14 and a second ring 16 stacked one over the other in the axial direction. Each of the first and second rings 14, 16 of the inner ring is provided with a plurality of aligned through holes (not shown) so as to be joined by means of assembly bolts.

[0031] In the example shown, the rolling bearing comprises two rows of axial rollers 18, 20 arranged between the inner ring 10 and the outer ring 12 to form an axial thrust, and one row of radial rollers 22 arranged between the inner ring 10 and the outer ring 12 to form a radial thrust.

[0032] As will be described later, the rolling bearing further comprises radial rollers 24 arranged in a row between the axial rollers 20 of the row Figure 2 ).

[0033] The rows of rollers 18, 20, 22 are identical to each other. Each roller 18, 20, 22 comprises a cylindrical outer rolling surface. Each roller 18, 20, 22 further comprises two facing front end faces delimiting the outer rolling surface.

[0034] The rotation axis of each roller 22 is parallel to the axis of the bearing and perpendicular to the axis of each of the rollers 18, 20. In the example shown, the axial length of the rollers 18 is greater than the axial length of the rollers 20. Alternatively, the axial length of the rollers 18 can be less than or can be equal to the axial length of the rollers 20.

[0035] The axial rollers 18 are axially interposed between an annular radial raceway 26 formed on the inner ring 10 and an annular radial raceway 28 formed on the outer ring 12. The raceways 26, 28 face each other in the axial direction.

[0036] The axial rollers 20 are axially interposed between an annular radial raceway 30 formed on the inner ring 10 and an annular radial raceway 32 formed on the outer ring 12. The raceways 30, 32 face each other in the axial direction. The rows of axial rollers 18, 20 are spaced apart from each other in the axial direction. The axial rollers 20 are radially located between an annular axial guide face 34 formed on the inner ring 10 and an annular axial guide face 36 formed on the outer ring 12. The guide faces 34, 36 face each other in the radial direction. Each guide face 30, 32 is straight and arranged perpendicular to the corresponding raceway 30, 32.

[0037] The raceway 30 and the guide face 34 of the inner ring, together with the raceway 32 and the guide face 36 of the outer ring, define an annular space inside which the axial rollers 20 are housed. The rolling surface of each axial roller 20 is in axial contact with the raceway 30, the raceway 32.

[0038] The radial rollers 22 are radially interposed between an annular axial raceway 38 formed on the inner ring 10 and an annular axial raceway 40 formed on the outer ring 12. The raceway 38, the raceway 40 face each other in the radial direction. The row of radial rollers 22 is radially inwardly offset with respect to the rows of axial rollers 18, 20. The row of radial rollers 22 is axially interposed between the row of axial rollers 18, the row of axial rollers 20.

[0039] The inner ring 10 comprises an annular groove 42 which opens outwardly in the radial direction towards the outer ring 12. The inner ring 10 comprises an outer stepped cylindrical surface 10a, the groove 42 being formed by the outer stepped cylindrical surface 10a.

[0040] The outer ring 12 comprises an annular protruding nose 44 which engages into the annular groove 42 of the inner ring. The nose 44 extends radially inwardly. The protruding nose 44 protrudes radially from the inner cylindrical surface or bore of the outer ring.

[0041] The rows of axial rollers 18, 20 are axially configured between the nose 44 of the outer ring and the groove 42 of the inner ring. The rows of axial rollers 18, 20 are arranged on either side of the nose 44. The radial raceways 28, 32 are located on the nose 44. The radial raceways 26, 30 are located on the groove 42 of the inner ring.

[0042] The row of radial rollers 22 is radially configured between the nose 44 of the outer ring and the groove 42 of the inner ring. The axial raceways 38, 40 are respectively located on the groove 42 and the nose 44. The inner cylindrical surface or bore of the nose 44 delimits the axial raceway 40. The axial bottom of the groove 42 delimits the axial raceway 38. The axial raceway 38 faces radially the inner cylindrical bore of the nose 44 on which the axial raceway 40 is formed.

[0043] In the example shown, the outer ring 12 is made in one piece. Alternatively, the outer ring 12 can be split in at least two separate pieces which are fixed together in the axial direction. As previously mentioned, the inner ring 10 is split in two separate pieces in the axial direction, i.e. the first ring 14 and the second ring 16. The first ring 14 and the second ring 16 together delimit the groove 42.

[0044] The rolling bearing further comprises a cage 50 for holding the axial rollers 20 spaced apart in the circumferential direction. The cage 50 maintains a regular circumferential spacing between the axial rollers 20. The cage 50 is housed within an annular space defined by the raceway 30 and the guide surface 34 of the inner ring and the raceway 32 and the guide surface 36 of the outer ring. Each axial roller 20 is held by the cage 50 which can bear against the guide surfaces 34, 36, 32.

[0045] As shown in Figure 3 , the cage 50 is segmented and formed by a plurality of consecutive cage segments 52. The cage 50 is formed as a split cage. The radial rollers 24 are interposed in the circumferential direction between each pair of two adjacent cage segments 52 of the segmented cage. Each radial roller 24 abuts one of the cage segments 52 on one side and the adjacent cage segment 52 on the other side.

[0046] Each cage segment 52 of the segmented cage delimits a plurality of pockets 54, each pocket 54 being configured to receive one axial roller 20. Advantageously, each cage segment 52 can be made in one piece, for example from a metal such as steel, brass or a plastic material. In the example shown, the cage segments 52 are identical to each other.

[0047] As shown more clearly in Figure 4 , each cage segment 52 is provided with an inner cylindrical portion 56 and an opposite outer cylindrical portion 58, which extend in the circumferential direction. The inner cylindrical portion 56 and the outer cylindrical portion 58 delimit the cage segment in the radial direction.

[0048] The inner cylindrical portion 56 comprises an outer surface (not referenced) oriented radially inwardly towards the guide surface 36 Figure 1 of the outer ring. The outer cylindrical portion 58 comprises an opposite outer surface (not referenced) oriented radially outwardly towards the guide surface 34 Figure 1 of the inner ring. These outer surfaces delimit the cage segment 36 in the radial direction. In the mounted position in the rolling bearing, the outer surface of the inner cylindrical portion 56 partially delimits the bore of the segmented cage and the outer surface of the outer cylindrical portion 58 partially delimits the outer surface of said cage.

[0049] The inner cylindrical portion 56 and the outer cylindrical portion 58 of each cage segment have an inner contact surface 56a and an inner contact surface 58a which face each other and form, for each pocket, an associated roller 20 Figure 3The contact surface 56a is a bearing surface of the end face of the inner cylindrical portion 56. The contact surface 58a is a bearing surface of the end face of the outer cylindrical portion 58. The spacing between the contact surface 56a and the contact surface 58a is substantially equal to the length of the roller 20.

[0050] In order to delimit the successive pockets 54, each cage segment 52 comprises a plurality of rim portions 50 extending radially between the inner cylindrical portion 56 and the outer cylindrical portion 58 and connected to said portions.

[0051] In the example shown, each cage segment 52 comprises three pockets 54. Alternatively, each cage segment 52 can comprise a different number of pockets. Preferably, each cage segment 52 is provided with at least two pockets 54.

[0052] Each cage segment 52 of the segmented cage further comprises two opposite abutment portions 62, 64 delimiting the cage segment in the circumferential direction and each comprising an outer abutment face 62a, 64a.

[0053] Referring again to Figure 3 , each radial roller 24 is circumferentially interposed between the outer abutment face 62a of one cage segment 52 and the outer abutment face 64a of the adjacent cage segment 52. Each outer abutment face 62a, 64a of each cage segment 52 forms a local raceway for the associated radial roller 24. The abutment faces 62a, 64a of each cage segment are symmetrical with respect to a radial plane passing through the center of said cage segment.

[0054] In the example shown, each abutment face 62a, 64a has a flat form. Alternatively, as shown in Figure 5 , each abutment face 62a, 64a has a concave form having the shape of a cylindrical segment. The radius of curvature of each abutment face 62a, 64a is slightly greater than the radius of the associated radial roller 24. The axis of the cylindrical segment of each abutment face 62a, 64a of each cage segment extends perpendicular to the axis of the associated axial roller of each pocket 54 of said cage segment. The axis of the cylindrical segment of each abutment face 62a, 64a is coaxial with the axis of the associated radial roller 24. The axis of the cylindrical segment of the abutment face 62a of each cage segment is parallel to the axis of the cylindrical segment of each abutment face 64a of said cage segment. The axis of the cylindrical segment of each abutment face 62a, 64a is outwardly offset in the circumferential direction with respect to said abutment face.

[0055] The radial rollers 24 are identical to each other. Each radial roller 24 comprises a cylindrical outer rolling surface. The axis of rotation of each radial roller 24 is parallel to the axis of the bearing and perpendicular to the axis of each of the axial rollers 18, 20.

[0056] With reference to Figure 2 The radial rollers 24 are radially interposed between the axial guide faces 34 of the inner ring and the axial guide faces 36 of the outer ring. The rolling surface of each radial roller 24 is in radial contact with the axial guide faces 34, 36. The radial rollers 24 are axially located between the radial raceways 30 of the inner ring and the radial raceways 32 of the outer ring.

[0057] The rolling bearing further comprises a cage 70 for retaining the axial rollers 18 spaced apart in the circumferential direction. The cage 70 is segmented and formed by a plurality of successive cage segments 72 which abut one against the other in the circumferential direction. The cage 70 is formed as a split cage.

[0058] In addition, as mentioned previously, in the example shown, the first ring of the rolling bearing is the inner ring 10 and the second ring is the outer ring 12.

[0059] As an alternative, an opposite configuration can be provided in which the first ring forms the outer ring and the second ring forms the inner ring. In this case, the grooves formed on the inner ring open radially inwards and the noses of the outer ring extend radially outwards.

[0060] In the example described, the rolling bearing is provided with a rolling bearing comprising three rows of rolling elements. As an alternative, the rolling bearing can comprise only two rows of rolling elements, or four or more rows of rolling elements. In the example shown, the rolling elements 18, 22 are rollers. The rolling bearing can comprise other types of rolling elements 18 and 22, such as balls.

Claims

1. A rolling bearing comprising a first ring (10), a second ring (12), at least one row of radial rolling elements (22) radially spaced between axial raceways (38, 40) of the first and second rings, at least one row of axial rolling elements (20) axially spaced between radial raceways (30, 32) of the first and second rings and radially located between axial guide surfaces (34, 36) of the first and second rings, and at least one cage (50) for retaining the row of said axial rolling elements (20), characterized in that, The cage (50) includes a plurality of consecutive circumferential cage segments (52), each cage segment having at least two cavities (54) each cavity (54) receiving at least one axial rolling element (20), and wherein the rolling bearing further includes at least one radial rolling element (24) circumferentially located between two adjacent cage segments (52) in the cage, and radially located between the axial guide surfaces (34, 36) of the first and second rings.

2. The rolling bearing according to claim 1, characterized in that, The rolling bearing includes a radial rolling element (24) located circumferentially between each end of each cage segment (52) in the cage and the facing end of the adjacent cage segment (52).

3. The rolling bearing according to claim 1 or 2, characterized in that, Each cage segment (52) in the cage includes two abutting ends (62, 64) that define the cage segment in the circumferential direction, and each abutting end includes an outer abutting surface (62a, 64a). The radial rolling element (24) abuts against the facing abutting surfaces (62a, 64a) of two adjacent cage segments (52) in the circumferential direction.

4. The rolling bearing according to claim 3, characterized in that, The outer abutment surfaces (62a, 64a) of each cage segment in the cage are flat.

5. The rolling bearing according to claim 3, characterized in that, The outer abutment surfaces (62a, 64a) of each cage segment in the cage are concave.

6. The rolling bearing according to claim 1 or 2, characterized in that, The second ring (12) includes a protruding nose (44) that engages in the annular groove (42) of the first ring and is provided with an axial cylindrical surface, wherein the axial raceway (40) of the second ring is formed on the axial cylindrical surface.

7. The rolling bearing according to claim 1 or 2, characterized in that, The rolling bearing further includes at least one additional row of axial rolling elements (18), which are axially positioned between the first radial raceway (26) and the second radial raceway (28).

8. The rolling bearing according to claim 7, characterized in that, The axial rolling elements (20) in the row and the axial rolling elements (18) in the additional row are arranged axially on both sides of the protruding nose (44) of the second ring.

9. The rolling bearing according to claim 1 or 2, characterized in that, The axial rolling elements (20) arranged in rows and the radial rolling elements (22) arranged in rows comprise cylindrical rollers.

10. The rolling bearing according to claim 1 or 2, characterized in that, The first ring (10) forms the inner ring, and the second ring (12) forms the outer ring, or vice versa.

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