Patent Publication Number: US-2023160421-A1

Title: Rolling bearing, notably large-diameter rolling bearing

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to German Patent Application no. 102021213235.9, filed Nov. 24, 2021, the contents of which is fully incorporated herein by reference. 
     TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to the field of bearings. The invention notably relates to the field of large-diameter rolling bearings that can accommodate axial and radial loads, and having an inner ring and an outer ring arranged concentrically about an axis of rotation running in an axial direction. 
     Such large-diameter rolling bearings may be used for example in a tunnel boring machine, in a mining extraction machine, in a big offshore crane or in a wind turbine. 
     A large-diameter rolling bearing comprises generally two concentric inner and outer rings, and a bearing assembly comprising two rows of axial rollers and one row of radial rollers. Such rolling bearings are generally loaded, both axially and radially, often with a relatively strong load. 
     Depending on the use of roller bearing, considerable titling moments may arise, which may cause deformation of the bearing, notably of the rotating ring, leading in some cases, to locally separate the rings. As a matter of fact, a radial gap between rotating ring and fixed ring of the roller bearing can be created. 
     One aim of the present invention is to overcome this drawback. 
     SUMMARY OF THE INVENTION 
     The invention relates to a rolling bearing comprising a first ring and a second ring capable of rotating concentrically relative to one another, at least one row of radial rolling elements radially interposed between raceways of the rings, and at least one row of axial rolling elements axially interposed between raceways of the rings. 
     The terms “axial rolling elements” is understood to mean rolling elements adapted to accommodate axial loads only whereas the terms “radial rolling elements” is understood to mean rolling elements adapted to accommodate radial loads only. 
     According to a general feature, the rolling bearing also comprises, axially on each side, at least one row of rolling elements radially interposed between raceways of the first and second rings. 
     With such an arrangement, if a tilting moment acts on the rolling bearing in the clockwise or counterclockwise direction, these rows of rolling elements prevent an angular displacement of the second ring relative to the first ring. Otherwise, these rows of rolling elements increase the rigidity of the rolling bearing. 
     The rolling bearing may comprise at least a first row of rolling elements arranged axially between the row of axial rolling elements and first frontal faces of the first and second rings, and at least a second row of rolling elements axially located between the row of radial rolling elements and second opposite frontal faces of the first and second rings. 
     In one embodiment, the rolling bearing further comprises at least one additional row of axial rolling elements axially interposed between raceways of the first and second rings, the rows of axial rolling elements being spaced apart from each other in the axial direction. 
     The second row of rolling elements may be axially located between the additional row of axial rolling elements and the second opposite frontal faces of the first and second rings. 
     In one embodiment, the second ring may comprise a protruding nose engaged into an annular groove of the first ring and provided with an axial cylindrical surface onto which is formed the raceway of the second ring. In this case, if the rolling bearing comprises the additional row of axial rolling elements, the additional row and the row of axial rolling elements are disposed axially on each side of the protruding nose of the second ring. 
     In one embodiment, each row of rolling elements is radially offset with respect to the row of axial rolling elements on the side opposite to the row of radial rolling elements. 
     Each row of rolling elements may comprise radial cylindrical rollers. 
     Each row of rolling elements may be located axially between shoulders of the first and second rings. In one embodiment, the first ring is provided with at least one plug extending into an orifice formed on the first ring and provided with an end face which is flush with one of the radial shoulders of the first ring. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       At least one of the embodiments of the present invention is accurately represented by this application&#39;s drawings which are relied on to illustrate such embodiment(s) to scale and the drawings are relied on to illustrate the relative size, proportions, and positioning of the individual components of the present invention accurately relative to each other and relative to the overall embodiment(s). Those of ordinary skill in the art will appreciate from this disclosure that the present invention is not limited to the scaled drawings and that the illustrated proportions, scale, and relative positioning can be varied without departing from the scope of the present invention as set forth in the broadest descriptions set forth in any portion of the originally filed specification and/or drawings. The present invention and its advantages will be better understood by studying the detailed description of specific embodiments given by way of non-limiting examples and illustrated by the appended drawings on which: 
         FIG.  1    is a cross-section of a rolling bearing according to an example of the invention, 
         FIGS.  2  and  3    are detail views of  FIG.  1   , 
         FIG.  4    is a partial cross-section of a rolling bearing according to another example of the invention, and 
         FIG.  5    is a partial exploded perspective view of  FIG.  4   . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Those of ordinary skill in the art will appreciate from this disclosure that when a range is provided such as (for example) an angle/distance/number/weight/volume/spacing being between one (1 of the appropriate unit) and ten (10 of the appropriate units) that specific support is provided by the specification to identify any number within the range as being disclosed for use with a preferred embodiment. For example, the recitation of a percentage of copper between one percent (1%) and twenty percent (20%) provides specific support for a preferred embodiment having two point three percent (2.3%) copper even if not separately listed herein and thus provides support for claiming a preferred embodiment having two point three percent (2.3%) copper. By way of an additional example, a recitation in the claims and/or in portions of an element moving along an arcuate path by at least twenty (20°) degrees, provides specific literal support for any angle greater than twenty (20°) degrees, such as twenty-three (23°) degrees, thirty (30°) degrees, thirty-three-point five (33.5°) degrees, forty-five (45°) degrees, fifty-two (52°) degrees, or the like and thus provides support for claiming a preferred embodiment with the element moving along the arcuate path thirty-three-point five (33.5°) degrees. The rolling bearing as illustrated on  FIG.  1    is a large-diameter rolling bearing comprising a first ring  10  and a second ring  12 . In the illustrated example, the first ring  10  is the inner ring whereas the second ring  12  is the outer ring. In this example, the outer ring  12  is a rotative ring and the inner ring  10  is a non-rotative ring. The rolling bearing may for example be used in a tunnel boring machine, a wind turbine, a big offshore crane or any other applications using a large diameter rolling bearing. 
     The inner and outer rings  10 ,  12  are concentric and extend axially along the bearing rotation axis (not shown) which runs in an axial direction. The rings  10 ,  12  are of the solid type. 
     The inner ring  10  is formed as a split ring and comprises a first ring  14  and a second ring  16  stacked one relative to 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 referenced) in order to be joined by fitting bolts. 
     In the illustrated example, the rolling bearing comprises first and second rows of axial rollers  18 ,  20  which are arranged between the inner and outer rings  10 ,  12  in order to form an axial thrust, and a row of radial rollers  22  arranged between the rings to form a radial thrust. 
     As will be described later, the rolling bearing further comprises, on each side, one row of radial rollers  24 ,  26  arranged between the inner and outer rings  10 ,  12 . 
     The rollers  18 ,  20 ,  22  of one row are identical to one another. Each roller  18 ,  20 ,  22  comprises a cylindrical outer rolling surface. Each roller  18 ,  20 ,  22  further comprises two opposite frontal end faces delimiting the outer rolling surface. 
     The axis of rotation of each roller  22  is parallel to the axis of the bearing and perpendicular to the axes of the rollers  18 ,  20 . In the illustrated example, the axial length of the rollers  18  is larger than the one of the rollers  20 . Alternatively, the axial length of the rollers  18  may be smaller than, or may be equal to, the one of the rollers  20 . Alternatively, the row of rollers  18  may be replaced by two rows of superimposed rollers. 
     The axial rollers  18  are interposed axially between annular radial raceways  32 ,  34  respectively formed on the inner and outer rings  10 ,  12 . The raceways  32 ,  34  face each other in the axial direction. The rolling surface of each axial roller  18  is in axial contact with the raceways  32 ,  34 . 
     The axial rollers  20  are interposed axially between annular radial raceways  36 ,  38  respectively formed on the inner and outer rings  10 ,  12 . The raceways  36 ,  38  axially face each other. The rolling surface of each axial roller  20  is in axial contact with the raceways  36 ,  38 . The rows of axial rollers  18 ,  20  are spaced apart from each other in the axial direction. 
     The radial rollers  22  are interposed radially between annular axial raceways  40 ,  42  respectively formed on the inner and outer rings  10 ,  12 . The raceways  40 ,  42  face each other in the radial direction. The row of radial rollers  22  is radially offset inwards with respect to the rows of axial rollers  18 ,  20 . The rolling surface of each radial roller  22  is in radial contact with the raceways  40 ,  42 . The row of radial rollers  22  is axially located between the rows of axial rollers  18 ,  20 . 
     The inner ring  10  comprises an annular groove  44  opening in a radial direction outwardly towards the outer ring  12 . The inner ring  10  comprises an outer stepped cylindrical surface  10   a  from which the groove  44  is formed. As previously mentioned, the inner ring  10  is divided in the axial direction in two separate parts, the first ring  14  and the second ring  16 . The first and second rings  14 ,  16  delimit together the groove  44 . 
     The inner ring  10  comprises the outer surface  10   a . The inner ring  10  also comprises an inner cylindrical bore  10   b  which is radially opposite to the outer surface  10   a . The inner ring  10  further comprises two opposite first and second frontal faces  10   c ,  10   d  which axially delimit the outer surface  10   a  and the bore  10   b.    
     The outer ring  12  comprises an annular protruding nose  46  engaging into the annular groove  44  of the inner ring. The nose  46  extends radially inwards. The nose  46  protrudes radially from an inner stepped surface or bore  12   a  of the outer ring. 
     The outer ring  12  also comprises an outer cylindrical surface  12   b  which is radially opposite to the bore  12   a . In the illustrated example, the outer surface  12   b  is provided with a gear teeth (not referenced). The outer ring  12  further comprises two opposite first and second frontal faces  12   c ,  12   d  which axially delimit the outer surface  12   b  and the bore  12   a.    
     In the illustrated example, the outer ring  12  is made in one part. Alternatively, the outer ring  12  may be formed in at least two separate parts secured together. 
     The rows of axial rollers  18 ,  20  are arranged axially between the nose  46  of the outer ring and the groove  44  of the inner ring. The rows of axial rollers  18 ,  20  are disposed on each side of the nose  46 . The radial raceways  34 ,  38  are located on the nose  46 . The radial raceways  32 ,  36  are located on the groove  44 . 
     The row of radial rollers  22  is arranged radially between the nose  46  of the outer ring and the groove  44  of the inner ring. The axial raceways  40 ,  42  are respectively located on the groove  44  and the nose  46 . An inner cylindrical surface or bore of the nose  46  delimits the axial raceway  42 . An axial bottom of the groove  44  delimits the axial raceway  40 . The axial raceway  40  radially faces the inner cylindrical bore of the nose  46  onto which is formed the axial raceway  42 . 
     The rolling bearing also comprises cages  48 ,  50  for maintaining the axial rollers  18 ,  20  spaced apart in the circumferential direction. Each cage  48 ,  50  is segmented and is formed by a plurality of successive cage segments abutting in the circumferential direction one relative to the other. Each cage  48 ,  50  is formed as a split cage. In this example, the rolling bearing does not comprise such a cage for the radial rollers  22 . 
     The radial rollers  22  comes into contact with each other in the circumferential direction. 
     As previously mentioned, the rolling bearing comprises the first and second row of radial rollers  24 ,  26  arranged between the inner and outer rings  10 ,  12 . 
     The rollers  24 ,  26  of one row are identical to one another. Each roller  24 ,  26  comprises a cylindrical outer rolling surface. Each roller  24 ,  26  further comprises two opposite frontal end faces delimiting the outer rolling surface. The axis of rotation of each roller  24 ,  26  is parallel to the axis of the bearing and parallel to the axes of the rollers  22 . 
     The radial rollers  24  are arranged axially between the row of axial rollers  18  and the frontal faces  10   c ,  12   c  of the inner and outer rings. The row of radial rollers  24  is radially offset outwards with respect to the rows of axial rollers  18 ,  20 . 
     The radial rollers  24  are interposed radially between annular axial raceways  52 ,  54  respectively formed on the inner and outer rings  10 ,  12 . The raceways  52 ,  54  face each other in the radial direction. The raceway  52  is formed on the outer surface  10   a  of the inner ring. The raceway  52  is axially offset outwards with respect to the radial raceway  32  for the rollers  18 . The raceway  54  is formed on the inner bore  12   a  of the outer ring. The rolling surface of each radial roller  24  is in radial contact with the raceways  52 ,  54 . The radial rollers  24  come into contact with each other in the circumferential direction. Thus, the rolling surfaces of the radial rollers  24  come into contact with each other in the circumferential direction. 
     The radial rollers  24  are located axially between radial shoulders  56 ,  58  respectively formed on the inner and outer rings  10 ,  12 . The shoulders  56 ,  58  face each other in the axial direction. Each shoulder  56 ,  58  is straight and disposed perpendicular to the corresponding raceway  52 ,  54 . Each shoulder  56 ,  58  extends radially from the corresponding raceway  52 ,  54 . The end faces of the rollers  24  may bear against the shoulders  56 ,  58 . 
     The raceway  52  and the shoulder  56  of the inner ring define together with the raceway  54  and the shoulder  58  of the outer ring an annular space inside which the radial rollers  24  are housed. 
     The radial rollers  26  are arranged axially between the row of axial rollers  20  and the frontal faces  10   d ,  12   d  of the inner and outer rings. The row of radial rollers  26  is radially offset outwards with respect to the rows of axial rollers  18 ,  20 . In the illustrated example, the row of radial rollers  26  is radially offset inwards with respect to the row of radial rollers  24 . Alternatively, the row of radial rollers  26  may be radially offset outwards with respect to the row of radial rollers  24 , or may be symmetric to the row of radial rollers  24  with regard to a radial plane of the rolling bearing. 
     The radial rollers  26  are interposed radially between annular axial raceways  62 ,  64  respectively formed on the inner and outer rings  10 ,  12 . The raceways  62 ,  64  face each other in the radial direction. The raceway  62  is formed on the outer surface  10   a  of the inner ring. The raceway  62  is axially offset outwards with respect to the radial raceway  36  for the rollers  20 . The raceway  64  is formed on the inner bore  12   a  of the outer ring. The rolling surface of each radial roller  26  is in radial contact with the raceways  62 ,  64 . The radial rollers  26  come into contact with each other in the circumferential direction. Thus, the rolling surfaces of the radial rollers  26  come into contact with each other in the circumferential direction. 
     The radial rollers  26  are located axially between radial shoulders  66 ,  68  respectively formed on the inner and outer rings  10 ,  12 . The shoulders  66 ,  68  face each other in the axial direction. Each shoulder  66 ,  68  is straight and disposed perpendicular to the corresponding raceway  62 ,  64 . Each shoulder  66 ,  68  extends radially from the corresponding raceway  62 ,  64 . The end faces of the rollers  26  may bear against the shoulders  56 ,  58 . 
     The raceway  62  and the shoulder  66  of the inner ring define together with the raceway  64  and the shoulder  68  of the outer ring an annular space inside which the radial rollers  26  are housed. 
     Considering the cross-section of  FIG.  1   , if a tilting moment acts on the rolling bearing in the clockwise direction, the roller  26  located on the upper side of  FIG.  1    and the roller  24  located on the lower side prevent an angular displacement of the outer ring  12  relative to the inner ring  10 . If a tilting moment acts on the rolling bearing in the counterclockwise direction, the roller  24  located on the upper side of  FIG.  1    and the roller  26  located on the lower side prevent an angular displacement of the outer ring  12  relative to the inner ring  10 . 
     As shown more clearly on  FIG.  2   , a chamfer  70  is provided on the bore  12   a  of the outer ring in the junction zone between this bore and the frontal face  12   c . The shape of the chamfer  70  is foreseen for easier mounting of the outer ring  10  on the first ring  14  of the inner ring during assembly. 
     Similarly, as shown more clearly on  FIG.  3   , a chamfer  72  is provided on the outer surface  10   a  of the inner ring in the junction zone between the raceways  36  and  62 . The shape of the chamfer  72  is foreseen for easier mounting of the second ring  16  of the inner ring inside the outer ring  10  during assembly. 
     The rolling bearing may be mounted as follows. In a first step, the first ring  14  of the inner ring already provided with the rows of rollers  24 ,  18  is mounted inside the outer ring. Then, in a second step, the row of rollers  22  is mounted on the first ring  14  of the inner ring, and the rows of rollers  20 ,  26  are mounted on the outer ring. Finally, in a third step, the second ring  16  of the inner ring is mounted inside the outer ring  10  in axial contact with the first ring  14 . 
     The example shown on  FIGS.  4  and  5   , in which identical parts are given identical references, differs from the first example in that the rolling bearing further comprises a plug  80  secured to the inner ring  10  in order to facilitate the mounting of the row of radial rollers  24 . In the illustrated example, the plug  80  is secured to the first ring  14  of the inner ring. An orifice  82  is formed both on the outer surface  10   a  and the frontal face  10   c  of the inner ring and is closed by the plug  80 . The orifice  82  extends axially from the frontal face  10   c  and opens on the radial shoulder  56  ( FIG.  1   ) of the inner ring. 
     The plug  80  is removably secured to the inner ring  10 , here by screwing. The plug  80  is provided with a radial end face  80   a  which is flush with the radial shoulder  56  of the inner ring so as to prevent surface discontinuity. The orifice  82  enables the introduction of the radial rollers  24  inside the bearing. 
     With such design with the orifice  82 , no chamfer is provided on the outer surface  10   a  of the inner ring in the junction zone between the raceways  36  and  62  as it is the case in the first example. 
     The rolling bearing may be mounted as follows. In a first step, the second ring  16  of the inner ring already provided with the rows of rollers  26 ,  20  is mounted inside the outer ring. Then, in a second step, the row of rollers  22  is mounted on the second ring  16  of the inner ring, the row of rollers  18  is mounted on the outer ring, and the first ring  14  of the inner ring is mounted inside the outer ring  10  in axial contact with the second ring  16 . 
     Then, in a third step, the row of rollers  24  is introduced between the inner and outer rings  10 ,  12  through the orifice  82 . Finally, in a fourth step, the plug  80  is secured to the inner ring  10 . 
     In the illustrated example, the inner ring  10  comprises only one orifice  82  and one associated plug  80  for the introduction of the rollers  26 . Alternatively, the inner ring  10  may comprise a plurality of orifices and associated plugs spaced apart in the circumferential direction for the introduction of the rollers  24 . In another variant, it could also be possible to provide plugs both on the first ring  14  and the second ring  16  of the inner ring for the introduction of the rollers  24 ,  26 . 
     Otherwise, as previously mentioned, in this illustrated example, the first ring of the rolling bearing is the inner ring  10  whereas the second ring is the outer ring  12 . 
     As an alternative, it could be possible to provide a reversed arrangement with the first ring forming the outer ring and the second ring forming the inner ring. In this case, the groove formed on the outer ring opens radially inwards and the nose of the inner ring extends radially outwards. 
     In the illustrated examples, the rolling bearing is provided with three rows of rolling elements  18 ,  20 ,  22  axially located between the rows of radial rollers  24 ,  26 . Alternatively, the rolling bearing may comprise only two rows of rolling elements, or four or more rows of rolling elements, axially located between the rows of radial rollers  24 ,  26 . In the illustrated example, the rolling elements  18 ,  22  are rollers. The rolling bearing may comprise other types of rolling elements  18  and  22 , for example balls. 
     In the illustrated examples, the rolling bearing is provided, axially on each side, with one row of radial rollers  24 ,  26 . Alternatively, the rolling bearing may be provided, axially on each side, with more rows of radial rollers. In the illustrated example, the rolling elements  24 ,  26  are rollers. The rolling bearing may comprise other types of rolling elements  24 ,  26 , for example balls.