Spherical roller bearings with separate cages

Abstract

Disclosed is a spherical roller bearing (1), in particular for supporting a wind turbine main shaft, comprising at least one outer ring (4) and one inner ring (6), wherein the inner ring (6) has a diameter of at least 499 mm, two sets of spherical rollers (8) rolling along raceways formed on the outer and inner rings (4, 6), wherein a first and a second cage (2-1, 2-2) are each adapted to retain a set of spherical rollers (8), wherein each of the first and second cages (2-1, 2-2) comprises a first cage ring (10-1, 10-2) extending in a circumferential direction of the spherical roller bearing (1), a second cage ring (12-1, 12-2) spaced from the first cage ring (10-1, 10-2) on one axial side and connected to it by a plurality of cage webs (14), whereby closed pockets (16), each pocket (16) being adapted toto accommodate a single barrel roller (8) of a set of barrel rollers.,

Description

Technical field of the invention

[0001] The present invention relates to a spherical roller bearing. Furthermore, the present invention relates to a bearing arrangement comprising a spherical roller bearing. Background of the invention

[0002] Rolling bearings are common mechanical components used in many different applications. There are various types of rolling bearings designed to meet different requirements. Depending on the conditions of the specific application, such as the degree of load, rotational speed, temperature, etc., different types of rolling bearings are suitable.

[0003] A common bearing type is a spherical roller bearing, as described, for example, in German patent applications DE 10 2015 225 678 A1 or DE 694 02 507 T2. This bearing is designed to withstand large radial and axial loads and is also designed to accommodate the deflection of a shaft supported by the bearings; that is, the bearing rings can be relatively misaligned. Therefore, such bearings are particularly suitable for demanding industrial applications, such as in wind turbine machinery and the like.

[0004] In most demanding industrial applications for spherical roller bearings, the majority of bearing failures are typically related to increased surface fatigue. One cause of increased surface fatigue can be insufficient bearing lubrication. Spherical roller bearings are usually relubricated during operation. A spherical roller bearing generally comprises two sets of rollers, and relubrication can be performed at a dedicated bore in the outer ring located midway between the two sets of rollers to lubricate both sets simultaneously. Furthermore, the addition of fresh lubricant can flush out any particles from the bearing that might otherwise increase the risk of surface fatigue.However, in most spherical roller bearings, the barrel rollers are held back in a cage, which usually has a central ring element that can act as a barrier to the added lubricant.

[0005] It is therefore an object of the present invention to improve the relubrication of a spherical roller bearing and its load-bearing capacity. Brief description of the invention

[0006] This task is accomplished by a spherical roller bearing according to claim 1.

[0007] The following is a spherical roller bearing. The spherical roller bearing can be used to support a wind turbine main shaft.

[0008] The spherical roller bearing comprises at least one outer ring and one inner ring and two sets of barrel rollers that roll along raceways formed in the outer and inner rings. The inner ring has a bore with a diameter of at least 499 mm, preferably at least 699 mm, and particularly preferably at least 899 mm. The bore may be designed to accommodate a component of another machine, for example, a shaft of a wind turbine.

[0009] The inner ring can be flanged or flangeless on an axial inner and / or outer surface. If the inner ring is flanged, the flanges can serve as guide flanges for the rolling elements. They can also act as retaining flanges to prevent the rollers from falling out of the bearings.

[0010] To improve the relubrication of the spherical roller bearing, the spherical roller bearing comprises a first and a second cage, each configured to retain a set of rollers, each of the first and second cages comprising a first cage ring extending in a circumferential direction of the spherical roller bearing, and a second cage ring spaced axially from the first cage ring and connected to it by several cage webs, thereby forming closed pockets, each pocket being configured to receive a single barrel roller of one set of rollers.

[0011] Furthermore, to increase the dynamic load rating of the spherical roller bearing, as many barrel rollers as possible are arranged in the spherical roller bearing. This is made possible by ensuring that the barrel rollers are equally spaced, with a minimum circumferential distance Dm between the raceways of two adjacent barrel rollers (8) of at least one set of barrel rollers (8) being equal to or less than a value obtained by the following equation: Dm≤0.0064 mm⋅(ln(P⋅Dw+Dw))3, when the barrel rollers (8) of the at least one set of barrel rollers (8) are uniformly spaced in the circumferential direction, where P is the pitch circle diameter and Dw is the maximum roller diameter, where the millimeter values ​​of P and Dw are to be used as dimensionless variables

[0012] The first and second cages can be separated from each other.

[0013] Two separate cages can allow one set of rollers to have a different rotational speed than the other set. This can reduce the forces acting on each cage compared to a single cage coupling the two sets of rollers. Alternatively, the first and second cages can be separated from each other but positioned close enough that they may support each other while still being able to move relative to one another.

[0014] According to another embodiment, the first and / or the second cage can be made of sheet metal.

[0015] Using sheet metal as the base material for the first and / or second cage can have the advantage of reducing the cost of the first and / or second cage.

[0016] Alternatively, the cage can also be made from a cast material or machined from a solid piece of material.

[0017] According to another embodiment, the pockets can be produced by pressing and embossing and / or milling.

[0018] According to another embodiment, the cage webs can be arranged at least partially in a position in a radial direction that is offset at least partially to a pitch circle diameter.

[0019] The term "pitch circle diameter" can describe the diameter along which the centers of the barrel rollers move during operation.

[0020] For example, the cage webs can be arranged at least partially at a distance from the raceway of the inner or outer ring in the radial direction that corresponds to 10 to 40% of the diameter of a barrel roller or 60 to 90% of the diameter of the barrel roller.

[0021] Furthermore, the at least one cage web can be arranged such that more than half of its length, or even its entire length, is offset from the pitch circle diameter in the axial direction. For example, the at least one cage web can be arranged such that more than half of its axial length, or even its entire axial length, lies on a radially inner or outer side of the pitch circle diameter. Additionally, several or even all of the cage webs can be arranged such that more than half of their axial length, or even their entire axial length, lies on a radially inner or outer side of the pitch circle diameter.

[0022] Positioning the cage webs in a radial direction offset from the pitch circle diameter allows for a reduction in the distance between two adjacent rollers, thus enabling an increase in the number of rollers in a roller set. Furthermore, positioning the cage webs in a radial direction offset at least partially from the pitch circle diameter allows for an increase in the cage web width, even with very small nominal roller spacing. In particular, increasing the number of rollers in the roller set offers the advantage of increasing the dynamic load rating of the spherical roller bearing without requiring modifications to the outer and / or inner rings of the bearing.

[0023] According to another embodiment, the inner ring is not provided with a flange designed to retain and / or guide the barrel rollers.

[0024] Equipping the first and second cages with closed pockets for the rollers offers the advantage of preventing axial movement of the roller. This eliminates the need for any guide and / or retaining flanges on the inner ring. Furthermore, manufacturing time can be reduced, as no machining of the flanges is required. Additionally, stresses in the inner ring can be reduced because no undercut needs to be created to form the retaining flange. This can reduce costs and / or the amount of raw material required for the inner ring.

[0025] According to another embodiment, the spherical roller bearing is not equipped with a guide ring.

[0026] A guide ring or center rib flange is typically used to limit roller misalignment in an unloaded zone of the spherical roller bearing, ensuring that the rollers enter the loaded zone with limited misalignment. This is particularly important in high-speed applications. Wind turbine main shaft applications are usually low-speed, operating at 15 rpm or less. This eliminates the need for a guide ring.

[0027] According to a further embodiment, the at least one cage can be free of any means for retaining at least one barrel roll in the at least one cage and / or in a pocket of the at least one cage.

[0028] In particular, the at least one cage and / or parts of the cage, such as the first cage ring, the second cage ring, the cage webs, or the like, can be free of any means for holding or retaining the barrel rollers, so that they cannot be lost. In other words, the at least one cage does not need to include means for snapping the barrel rollers into the at least one cage, nor recesses formed on the axial end faces of the pockets to engage with notches formed on the end faces of the barrel rollers. Due to the absence of retaining means, the manufacturing costs for the at least one cage can be reduced. Since the at least one cage can be free of any means for retaining at least one barrel roller within the cage, it may also be possible to replace individual barrel rollers, for example, during maintenance work.

[0029] According to a further embodiment, the at least one cage and / or the barrel rollers can be mounted in the spherical roller bearing without elastic and / or plastic deformation of the at least one cage and / or without disassembling the at least one cage. In particular, the phrase "deformation of the at least one cage and / or disassembly of the at least one cage" can refer to a method for bending, twisting, warping, cutting, or otherwise disassembling the at least one cage in order to mount the at least one cage and / or one of the barrel rollers in the spherical roller bearing.

[0030] According to a further embodiment, the ratio Dm / Dw of a minimum distance Dm in the circumferential direction between the raceways of two adjacent barrel rollers of at least one set of barrel rollers to a maximum roller diameter Dw is equal to or less than 0.11, preferably 0.09 and particularly preferably 0.075, if the barrel rollers of the at least one set of barrel rollers are uniformly spaced in the circumferential direction.

[0031] Reducing the distance between two rollers in the circumferential direction allows for an increase in the number of rollers in the set. For example, it may be possible to increase the number of rollers in the set by at least one. This can increase the dynamic load rating of the spherical roller bearing. Furthermore, increasing the number of rollers in the set by at least one can significantly extend the service life of the spherical roller bearing.Furthermore, the ratio Dm / Dw of the minimum circumferential distance Dm between the raceways of two adjacent barrel rollers of the first set of rollers to the maximum roller diameter Dw, if the barrel rollers of the first set of rollers are uniformly spaced in the circumferential direction, can be the same as, or different from, the ratio Dm / Dw of the minimum circumferential distance Dm between the raceways of two adjacent barrel rollers of the second set of rollers to the maximum roller diameter Dw, if the barrel rollers of the second set of rollers are uniformly spaced in the circumferential direction.

[0032] As mentioned above, if the barrel rollers of at least one set of barrel rollers are uniformly spaced in the circumferential direction, the minimum circumferential distance Dm between the raceways of two adjacent barrel rollers of the at least one set of barrel rollers is equal to or less than a value obtained by the following equation: Dm≤0.0064 mm⋅(ln(P⋅Dw+Dw))3 where P is the pitch circle diameter and Dw is the maximum roller diameter, with the millimeter values ​​of P and Dw being used as dimensionless variables. Furthermore, the minimum circumferential distance Dm between the raceways of two adjacent barrel rollers of the first set of rollers, if the barrel rollers of the first set of rollers are uniformly spaced circumferentially, can be the same as, or different from, the minimum circumferential distance Dm between the raceways of two adjacent barrel rollers of the second set of rollers, if the barrel rollers of the second set of rollers are uniformly spaced circumferentially.

[0033] According to another embodiment, each set of barrel rollers can comprise the same number of barrel rollers. Preferably, each set of barrel rollers can comprise the maximum number of barrel rollers.

[0034] Equipping the spherical roller bearing with the maximum number of tonneau rollers can allow the dynamic load rating of the spherical roller bearing to be increased.

[0035] According to a further embodiment, the first cage ring of each cage is arranged on an axially inner side of the spherical roller bearing such that a gap is formed at least partially between the first cage ring of the first cage and the first cage ring of the second cage.

[0036] Advantageously, the first cage rings of the first and second cages can act like a funnel, transporting a lubricant to the inner ring of the spherical roller bearing.

[0037] Preferably, the size of the gap in the axial direction can be at least 0.5 mm, preferably at least 1 mm. In particular, the size of the gap can be determined in a state in which the barrel rollers, the first cage, and the second cage of the spherical roller bearing are in a nominal position. More precisely, a nominal roller position can be a position in which a contact angle of the spherical roller bearing is satisfied, and a nominal cage position can be a position in which an axis of rotation of the first and second cage axes coincides with the axis of rotation of the inner ring, and the axial clearance of the cage pockets is uniformly distributed such that the same clearance exists between the roller side face and the cage pocket side face on both the axial inner and the axial outer surfaces of each cage.

[0038] According to another embodiment, the first cage ring and / or at least one of the second cage rings has a flange element that extends radially inwards or radially outwards.

[0039] The presence of a flange element extending radially inwards or radially outwards can allow cage deformations to be limited if strong forces act on the first and / or the second cage, causing cage deformation.

[0040] According to a further embodiment, the first cage ring and at least one of the second cage rings have a radially extending flange element, with both flange elements extending radially inwards or radially outwards.

[0041] Equipping both cage rings with a radially extending flange element can lead to a further increase in cage stiffness. The benefits are reduced cage deformation and improved cage performance.

[0042] According to a further embodiment, the first cage ring and at least one of the second cage rings can have a radially extending flange element, wherein one flange element extends radially inwards and the other flange element extends radially outwards.

[0043] If one flange element extends radially inwards and the other flange element extends radially outwards, this can lead to a significant increase in stiffness. This allows for a further reduction in cage deformation and can result in improved cage performance.

[0044] According to a further embodiment, a free end of the flange element of the first cage rings is inclined towards the barrel roller. Preferably, the free ends of the flange element of the first cage rings can have an opening angle in the range between 2° and 40°. This can have the advantage of further improving lubricant flow towards the inner ring.

[0045] According to another embodiment, shoulder play is greater than radial cage play.

[0046] In particular, the shoulder clearance can be defined as the difference between the bore diameter of the cage ring and the diameter of the inner ring at a specific position on the cage ring. By designing the cage such that the shoulder clearance is greater than the radial cage clearance, it is possible to design the cage with roller guidance.

[0047] For example, the shoulder clearance can be designed to be between 1 and 15 mm larger than the radial cage clearance if the cage bore diameter is up to 1200 mm. If the cage bore diameter is larger than 1200 mm, the shoulder clearance can be designed to be between 1 and 20 mm larger than the radial cage clearance.

[0048] Furthermore, the radial cage clearance can be in the range of 0.2 to 5 mm, preferably between 0.5 and 3 mm. The radial cage clearance can be measured by the maximum radial movement of the first and / or the second cage inside the bearing.

[0049] According to another embodiment, the first and / or the second cage is predominantly roller-guided.

[0050] The term "predominantly roller-guided" refers to a case where the cage is normally roller-guided, but in cases where the cage deforms, for example, due to high forces acting on it, the deformation can be limited by the cage bore. This can limit extreme loads on the cage. This guiding principle can also be described as "mixed guidance." Alternatively, the first and / or second cage need only be roller-guided. In other words, even if the cage deforms, it is designed so that no contact occurs between the cage rings and the inner or outer ring. Roller-guided and / or predominantly roller-guided cages can have the advantage of being subject to less wear compared to shoulder-guided cages. This can mean fewer particles in the bearing, which can lead to an extended service life.

[0051] In another alternative design, the first and / or the second cage can be predominantly shoulder-guided at the cage bore and / or supported on a central rib or guide flange of the inner ring.

[0052] According to another embodiment, each pocket of the first and / or the second cage is designed to limit any skew of the barrel roller held in the pocket.

[0053] Limiting the skew of the barrel roller in the pocket can reduce the contact force generated by the roller's contact with the cage. This can further lead to less wear on the first and / or second cage.

[0054] For example, the roller's skew in the pocket can be limited by radial cage clearance. Additionally or alternatively, the roller skew can be limited by axial cage pocket clearance. In particular, the axial cage pocket clearance can be between 0.2 and 2.5 mm, preferably between 0.5 and 2 mm, and most preferably between 0.7 and 1.5 mm.

[0055] According to a further embodiment, each cage web can be provided with a contact surface designed to contact the barrel roller, the contact surface being positioned on a circumferential side surface of each cage web.

[0056] Furthermore, the contact surface can be provided with a radius. This allows the contact between the roller and the contact surface to still occur tangentially with reduced contact loads in the event of misalignment and / or axial movement of the roller. This can lead to a reduced risk of wear.

[0057] According to another embodiment, a circumferential side surface of each cage web can be provided with a single contact area in the axial direction.

[0058] For example, the circumferential side face of each cage web can be provided with an osculation between the cage web and the roller. The osculation, which is the radius of the cage web divided by the crown radius of the roller, can be between 100% and 104%. This can lead to a reduction in contact stresses compared to a straight cage web.

[0059] According to another embodiment, a circumferential side surface of each cage web can be provided in the axial direction with at least two contact areas designed to contact the roller.

[0060] Preferably, the contact areas can be located next to the side faces of the roller. The presence of at least two contact areas can reduce roller misalignment. Furthermore, at least two contact areas can have the advantage of reducing stress on the first and / or the second cage. In particular, if a contact point between the roller and the cage web is located as close as possible to the cage rings, the bending moment of the cage web can be reduced, resulting in lower stress within the first and / or second cage.

[0061] According to another aspect, a bearing arrangement is provided for a wind turbine main shaft, wherein the bearing arrangement includes at least one spherical roller bearing as described above.

[0062] All the characteristics described above in relation to the spherical roller bearing apply - separately or in combination - to the spherical roller bearing used in the bearing arrangement.

[0063] Further preferred embodiments are defined in the dependent claims, the description, and the figures. Elements described or shown in combination with other elements may be present alone or in combination with other elements without exceeding the scope of protection. Brief description of the drawings

[0064] Preferred embodiments of the invention are described below with reference to the drawings, which are merely exemplary and are not intended to limit the scope of protection. The scope of protection is defined exclusively by the accompanying claims.

[0065] The figures show: Fig. Figure 1 shows a schematic cross-section of a spherical roller bearing according to a first embodiment, Fig. 2: shows a schematic cross-section of a barrel roller at a maximum diameter of the barrel roller in a cage of the spherical roller bearing according to the first embodiment, Fig. Figure 3 shows a schematic perspective view of a first cage of the spherical roller bearing according to the first embodiment. Fig. 4: shows a section of a side view of the spherical roller bearing according to the first embodiment and Fig. Figure 5 shows a schematic cross-section of a cage of a spherical roller bearing according to a second embodiment. Detailed description of the invention

[0066] In the following, identical or similar functional elements will be designated with the same reference symbols.

[0067] Fig. Figures 1 to 4 show a spherical roller bearing 1 for supporting a wind turbine main shaft and a first cage 2-1 of the spherical roller bearing 1.

[0068] The spherical roller bearing 1 comprises an outer ring 4 and an inner ring 6, and two sets of barrel rollers 8 that roll along raceways 9 formed on the outer ring 4 and raceways 11 formed on the inner ring 6. The outer ring 4 includes an opening 5 through which lubricant can be supplied to the spherical roller bearing 1. In particular, the outer ring can be stationary, while the inner ring can rotate about an axis of rotation A. Furthermore, the inner ring 6 can be configured to be mounted on a main shaft of a wind turbine.

[0069] The inner ring 6 can be designed with or without flanges on an axial inner and / or an axial outer surface. The in Fig. The spherical roller bearing shown in Figure 1 is designed without flanges on both the axial inside and the axial outside of the inner ring 6.

[0070] Furthermore, the spherical roller bearing comprises a first cage 2-1, configured to retain the first set of barrel rollers 8, and a second cage 2-2, configured to retain the second set of barrel rollers 8. The first and second cages 2-1, 2-2 have an identical shape. Fig. Figure 2 shows the first cage 2-1 in detail.

[0071] Furthermore, both the first cage 2-1 and the second cage 2-2 are free of any means for retaining at least one barrel roller 8 either in the first cage 2-1 or the second cage 2-2 or in a pocket 16 of the first and / or the second cage 2-1, 2-2. In other words, the first cage 2-1 and the second cage 2-2 do not include means for snapping the barrel rollers 8 into the cages 2-1, 2-2, nor recesses formed on the axial end faces of the pockets 16 to engage with recesses formed on the end faces of the barrel rollers 8.

[0072] Furthermore, the first and second cages 2-1, 2-2 can be mounted or installed in the spherical roller bearing 1 without elastically and / or plastically deforming the first and second cages 2-1, 2-2 and / or without disassembling or cutting the first and second cages 2-1, 2-2.

[0073] Each cage 2-1, 2-2 comprises a first cage ring 10-1, 10-2 extending in a circumferential direction of the bearing, a second cage ring 12-1, 12-2 axially spaced from the first cage ring 10-1, 10-2 and connected to it by several cage webs 14, thereby forming closed pockets 16. Each pocket 16 is configured to receive a single barrel roller 8. In particular, each cage 2-1, 2-2 can be integrally formed.

[0074] The first cage ring 10-1, 10-2 has a flange element 18 extending radially outwards, and the second cage ring 12-1, 12-2 has a flange element 20 extending radially inwards.

[0075] The free ends of the flange elements 18 of the first cage rings 10-1, 10-2 are inclined towards the barrel roller 8 such that the free ends form an opening angle α. Preferably, the opening angle α is in the range between 2° and 40°.

[0076] Furthermore, the cage webs 14 are at least partially arranged in a position offset from the radial inner side of a pitch circle diameter P of the spherical roller bearing 1. Preferably, the position corresponds to 10 to 40% of the maximum diameter Dw of the barrel roller 8 used in the spherical roller bearing 1. In the embodiment shown, the cage web 14 is arranged such that contact between the barrel roller 8 and the cage web 14 occurs in a position that corresponds to approximately 30% of a maximum diameter Dw (as indicated by the dashed line 17) of the barrel roller 8. The maximum diameter Dw of the barrel roller 8 is given in Fig. 4 indicated.

[0077] Arranging the cage bars 14 in an offset to the pitch circle diameter P can allow a minimum distance Dm ( Fig. 4) to reduce the distance between the raceways of two adjacent rollers 8 so that it is possible to increase the number of rollers used in a set of rollers 8. The minimum distance Dm is determined in a state where the barrel rollers 8 are uniformly spaced in the circumferential direction.

[0078] In particular, the ratio Dm / Dw of the minimum distance in the circumferential direction between the raceways of two adjacent barrel rollers 8 of the first and / or the second set of barrel rollers to the maximum roller diameter Dw is equal to or less than 0.11, preferably 0.09 and particularly preferably 0.075%, if the barrel rollers 8 of the respective set of rollers 8 are uniformly spaced in the circumferential direction.

[0079] Alternatively or additionally, the minimum distance Dm in the circumferential direction between the raceways of two adjacent barrel rollers of the first and / or the second set of barrel rollers can be equal to or less than a value obtained by the following equation: Dm≤0.0064 mm⋅(ln(P⋅Dw+Dw))3 when the barrel rollers 8 of the respective set of rollers 8 are uniformly spaced in the circumferential direction, where P is the pitch circle diameter and Dw is the maximum roller diameter, where the millimeter values ​​of P and Dw are to be used as dimensionless variables.

[0080] The spherical roller bearing 1 is designed such that the shoulder clearance is greater than the radial cage clearance. For example, the shoulder clearance can be between 1 and 15 mm greater than the radial cage clearance if the cage bore diameter is up to 1200 mm. If the cage bore diameter is greater than 1200 mm, the shoulder clearance can be between 1 and 20 mm greater than the radial cage clearance. This allows the cage 2 to be designed with predominantly roller guidance.

[0081] Furthermore, each cage web 14 of the cages 2-1, 2-2 of the spherical roller bearing 1 according to the first embodiment is provided with at least one contact area 24 which is configured to contact the barrel roller 8, wherein the contact area 24 is positioned on a circumferential side surface 22 of each cage web 14.

[0082] The contact surface or contact area 24 is at least partially provided with a radius such that an osculation is formed between the cage web 14 and the roller 8 along the roller axis. The osculation, which is the radius of the cage web 14 divided by a crown radius of the roller, can be between 100% and 104%. Furthermore, each cage web 14 of the spherical roller bearing 1 according to the first embodiment has a single contact area 24 in the axial direction.

[0083] Fig. Figure 5 shows a cross-section of a cage 2 for a spherical roller bearing 1 according to a second embodiment. The cage 2 of the second embodiment differs from the cage 2 of the first embodiment in that a circumferential side surface 22 of each cage web 14 is provided in the axial direction with two contact areas 24-1, 24-2 which are configured to contact the roller.

[0084] Although Fig.Figure 5 shows an embodiment which has two contact areas 24-1, 24-2, it may also be possible to provide more than two contact areas.

[0085] In summary, providing two separate cages 2-1, 2-2 can have the advantage of improving lubricant flow to the inner ring 6. Specifically, a gap formed between the first cage rings 10-1, 10-2 of the first and second cages 2-1, 2-2 can act like a funnel, transporting the lubricant to the inner ring 6 of the spherical roller bearing 1. Furthermore, the presence of two separate cages 2-1, 2-2 allows the first row of barrel rollers 8, held in the first cage 2-1, to have a different rotational speed than the second row of barrel rollers 8, held by the second cage 2-2. This can reduce the forces acting on the cages 2-1, 2-2 compared to a design using only a single cage. Reference symbol list 1 spherical roller bearing 2-1 first cage 2-2 second cage 4 outer ring 5 Opening 6 inner ring 8-ton roller 9 outer lane 10-1, 10-2 first cage ring 11 inner career 12-1, 12-2 second cage ring 14 Cage bridge 16 bags 18 Flange element 20 Flange element 22 Perimeter side area 24 contact area α Opening angle A axis of rotation

Claims

[1] Spherical roller bearings (1), in particular for supporting a wind turbine main shaft, comprising: at least one outer ring (4) and one inner ring (6), wherein the inner ring (6) has a diameter of at least 499 mm, two sets of barrel rollers (8) which roll along raceways formed on the outer and inner rings (4, 6), characterized bya first and a second cage (2-1, 2-2), each configured to retain a set of barrel rollers (8), each of the first and second cages (2-1, 2-2) comprising a first cage ring (10-1, 10-2) extending in a circumferential direction of the spherical roller bearing (1), a second cage ring (12-1, 12-2) spaced axially from the first cage ring (10-1, 10-2) and connected to it by several cage webs (14), forming closed pockets (16), each pocket (16) being configured to receive a single barrel roller (8) of a set of barrel rollers, furthermore a minimum circumferential distance Dm between the raceways of two adjacent barrel rollers (8) of at least one set of barrel rollers (8) being equal to or less than a value obtained by the following equation: Dm≤0.0064 mm⋅(ln(P⋅Dw+Dw))3, when the barrel rollers (8) of the at least one set of barrel rollers (8) are uniformly spaced in the circumferential direction, where P is the pitch circle diameter and Dw is the maximum roller diameter, where the millimeter values ​​of P and Dw are to be used as dimensionless variables. [2] Spherical roller bearing (1) according to claim 1, wherein the inner ring (6) is not provided with a flange designed to retain and / or guide the barrel rollers, and / or wherein the spherical roller bearing (1) is not equipped with a guide ring. [3] Spherical roller bearing (1) according to claim 1 or 2, wherein a ratio Dm / Dw of a minimum distance Dm in the circumferential direction between the raceways of two adjacent barrel rollers (8) of at least one set of barrel rollers (8) to a maximum roller diameter (Dw) is equal to or less than 0.11, preferably 0.09 and particularly preferably 0.075, when the barrel rollers (8) of the at least one set of rollers (8) are spaced uniformly apart in the circumferential direction. [4] Spherical roller bearing (1) according to one of the preceding claims, wherein the first cage ring (10-1, 10-2) of each cage (2-1, 2-2) is arranged on an axially inner side of the spherical roller bearing (1) such that a gap is formed at least partially between the first cage ring (10-1) of the first cage (2-1) and the first cage ring (10-2) of the second cage (2-2). [5] Spherical roller bearing (1) according to claim 4, wherein the size of the gap in the axial direction is at least 0.5 mm, preferably at least 1 mm. [6] Spherical roller bearing (1) according to one of the preceding claims, wherein the first cage ring (10-1, 10-2) and / or at least one of the second cage rings (12-1, 12-2) has a flange element (18, 20) extending radially inwards or radially outwards, or the first cage ring (10-1, 10-2) and at least one of the second cage rings (12-1, 12-2) has a radially extending flange element (18, 20), wherein both flange elements (18, 20) extend radially inwards or radially outwards, or the first cage ring (10-1, 10-2) and at least one of the second cage rings (12-1, 12-2) has a radially extending flange element (18, 20), wherein one flange element (18, 20) extends radially inwards and the other flange element (18, 20) extends radially outwards. [7] Spherical roller bearing (1) according to claim 6, wherein a free end of the flange element (18) of the first cage ring (10-1, 10-2) is inclined in the direction of the barrel roller (8). [8] Spherical roller bearing (1) according to claim 7, wherein the free ends of the flange element (18) of the first cage rings (10-1, 10-2) have an opening angle (α) in the range between 2° and 40°. [9] Spherical roller bearing (1) according to one of the preceding claims, wherein the first and / or the second cage (2-1, 2-2) are predominantly roller-guided. [10] Spherical roller bearing (1) according to one of the preceding claims, wherein a shoulder clearance is greater than a radial cage clearance. [11] Spherical roller bearing (1) according to one of the preceding claims, wherein a circumferential side surface (22) of the cage webs (14) is provided in the axial direction with a single contact area (24) or at least two contact areas (24-1, 24-2) which are configured to contact the barrel roller (8). [12] Spherical roller bearing (1) according to one of the preceding claims, wherein at least one of the first and second cages (2-1, 2-2) is made of sheet metal. [13] Spherical roller bearing (1) according to any one of the preceding claims, wherein the at least one cage (2) is free from any means of retaining at least one barrel roll (8) in the at least one cage (2) and / or in a pocket (16) of the at least one cage (2), and / or wherein the at least one cage (2) and / or the barrel rollers (8) can be mounted in the spherical roller bearing (1) without elastic and / or plastic deformation of the at least one cage (2) and / or without dismantling the at least one cage (2). [14] Bearing arrangement for a wind turbine main shaft, wherein the bearing arrangement comprises at least one spherical roller bearing (1) according to one of the preceding claims.

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