Bearing unit and wind turbine having a bearing unit

Abstract

The invention relates to a bearing unit (1) for attaching a rotor blade to a hub (150) of a wind turbine, the unit comprising: a first bearing ring (2) for attachment to the hub (150); a second bearing ring (4) for attachment to the rotor blade; at least one row of rolling bodies (7, 8); and an adjustment drive (9) for adjusting the angle of the two bearing rings (2, 4) relative to one another; wherein the first bearing ring (2) is formed in one piece with a rotor hub extension (10) which extends on the hub side in the axial direction (A) beyond the second bearing ring (4), wherein the adjustment drive (9) comprises at least one electric adjustment motor (11) and a shaft (12) which is driven by the adjustment motor (11) and has a drive pinion (13) which meshes with toothing (14) formed on the inside of the first bearing ring (2), wherein the adjustment motor (11) is arranged on the blade side on a reinforcing plate (15) mounted on the second bearing ring (4) and the shaft (12) extends through an eccentrically arranged recess (16) in the reinforcing plate (15). The invention also relates to a wind turbine having such a bearing unit.

Description

[0001] Storage unit and wind turbine with a storage unit

[0002] State of the art

[0003] The invention relates to a bearing unit for the fastening and angular adjustment of a rotor blade on a hub of a wind turbine according to the preamble of claim 1, as well as to a wind turbine according to the preamble of claim 13.

[0004] The rotor blades of wind turbines are attached to the hub using slewing bearings. These slewing bearings enable the adjustment of the rotor blades' angle of attack to the wind, which is necessary, among other things, for controlling the turbine's power. In addition to the bearing, a drive is required for adjustment. This drive is conventionally mounted on the hub side, i.e., fixed, and enables blade adjustment, for example, via a hydraulic cylinder acting on the rotating part of the blade bearing unit.

[0005] Traditionally, the hub, along with the attached slewing bearings and blade pitch drives, could be transported pre-assembled to the wind turbine construction site. However, due to the continuously increasing rated power and the associated size growth of wind turbines, pre-assembled hubs matching the desired blade root diameters are often no longer transportable by road. To overcome this obstacle, so-called extender solutions have been developed that aim to keep the hub as compact as possible. Hub extenders are then mounted on the hub's connection surfaces, which in turn support the slewing bearings to which the rotor blades are attached. In this way, the transport restrictions can be circumvented by transporting several more compact components to the construction site and assembling them there.

[0006] To further increase the rigidity of the structure and simultaneously adapt the hub- and blade-side screw connection diameters specifically to ensure hub compactness or to increase the blade root diameter to be used, DE 10 2018 211 430 A1 discloses the integration of an extender and a slewing bearing. The hub-side bearing ring of the slewing bearing is formed integrally with a rotor hub extension. Furthermore, a pitch drive can be formed as part of the rotor hub extension or located within the rotor hub extension.

[0007] Typically, the pitch drive is still designed as a hydraulic adjustment cylinder, which is mounted on the hub side together with the stationary part of the slewing bearing. This is particularly advantageous with regard to the supply of hydraulic fluid, which is stored centrally in the hub for all pitch drives, because then the hydraulic fluid does not need to be transferred to the rotating blade.

[0008] In addition to hydraulic drives, electric drives for rotor blade adjustment are also known, for example from US 2008 / 0191488 A1. The pitch drive described is also mounted on the hub side of the fixed part and engages with a gear on the blade-side inner ring of the blade bearing.

[0009] However, the use of such an electric drive in an integrated hub extender with a blade bearing is ruled out because an electric drive mounted on a hub-side stiffening plate must not only bridge the axial extent of the extender up to the tooth engagement with the blade-side component of the bearing, but also, due to the radial extent of the extender, provide sufficiently stable gearing with a suitable tooth diameter on the blade side, with a corresponding radial offset to the blade-side bearing ring. This would only be possible with considerable design effort and would result in a correspondingly expensive and heavy technical solution.

[0010] Disclosure of the invention

[0011] The object of the invention is therefore to provide a bearing unit for the attachment and angle adjustment of a rotor blade to the hub of a wind turbine and a wind turbine which, despite the use of a rotor hub extension, enables a cost-effective and simple structural connection of the blade adjustment drive, thereby simplifying the assembly of the bearing unit and also the installation in the field and improving the accessibility of the drive components of the blade adjustment for maintenance work.

[0012] This object is achieved by a bearing unit having the features of claim 1 and a wind turbine having the features of claim 13. This creates a bearing unit for fastening and angularly adjusting a rotor blade to a hub of a wind turbine, comprising a first bearing ring with first fastening bores for fastening to the hub and a second bearing ring with second fastening bores for fastening to the rotor blade. The second bearing ring is coaxial with the first bearing ring and is arranged so as to be rotatable about the common axis relative to the first bearing ring. The bearing unit further comprises at least one row of rolling elements which can roll between the bearing rings in a raceway system and an adjustment drive which is designed to angularly adjust the two bearing rings relative to one another.The first bearing ring is formed integrally with a rotor hub extension, which extends on the hub side in the axial direction beyond the second bearing ring and in whose hub-side end region the first fastening bores are arranged. According to the invention, the adjustment drive comprises at least one electric adjustment motor, a shaft driven by the adjustment motor, and a drive pinion arranged on the shaft. The drive pinion meshes with a toothing formed on the inside of the first bearing ring. The adjustment motor is arranged on the blade side on a stiffening plate mounted on the second bearing ring, and the shaft extends through an eccentrically arranged recess in the stiffening plate.

[0013] By attaching the adjustment motor to a stiffening plate of the rotating bearing ring of the bearing unit on the blade side, the available space in the rotor blade is used to accommodate the adjustment motor. The use of an electric adjustment motor as a rotating drive simplifies the structural design as well as the assembly and installation of the bearing unit in the wind turbine in the field. The power supply to the motor on the rotating ring can be provided via a simple slip ring from the hub. In contrast to a hydraulic supply, no pressure-tight rotary unions are required. The inventive integration of the adjustment drive in the bearing unit reduces the assembly work to be carried out on site to screwing the bearing unit together on the hub and blade sides, as well as creating an electrical power supply.The space available in the hub in the connection area of ​​the blade bearing unit remains free for assembly and maintenance work or the attachment of additional stiffening elements to the hub. The bearing unit according to the invention can thus be delivered to the construction site completely prefabricated, assembled, and tested ("ready-to-run") independently of the hub and easily installed. In some embodiments, the adjustment drive comprises a gearbox interposed between the adjustment motor and the shaft. The gearbox adapts the motor speed to the desired adjustment speed of the rotor blade.

[0014] Preferably, a control unit for controlling the electric adjustment motor can also be arranged on the stiffening plate, preferably on the side facing the hub. By arranging the control unit on the stiffening plate, additional installation space remains free inside the hub. When using several bearing units according to the invention on a hub of a wind turbine, a single control unit arranged on the stiffening plate can be provided for controlling the adjustment motors of all bearing units.

[0015] Preferably, a battery unit for emergency operation of the adjustment motor can be arranged on the stiffening plate, preferably on the side facing the hub. The battery unit can ensure an autonomous supply of electrical power to the adjustment motor for a limited period of time. In particular, the battery unit can have a capacity that enables at least one emergency shutdown of the wind turbine by moving the rotor blade to the feathered position.

[0016] In some embodiments, the first bearing ring forms the outer ring of the bearing unit, and the toothing is formed in the hub-side end region of the rotor hub extension. These embodiments have the advantage that the adjusting forces introduced via the toothing are introduced into the bearing unit by the rotor hub extension at a distance from the raceway system of the bearing unit. Ring deformations, such as those that can occur due to the introduction of high adjusting or holding forces on the toothing, are thus only transmitted to the raceway system in a weakened form. The raceway system of the bearing unit is therefore not impaired in its function or even damaged, even under high forces. In particular, it is preferred if the toothing is spaced from the raceway system along the extent of the rotor hub extension by a distance that corresponds to at least half the axial extent of the second bearing ring.

[0017] In embodiments in which the first bearing ring forms the outer ring of the bearing unit, it is preferred if the stiffening plate is bolted to the second bearing ring on the hub side. In this way, the axial distance between the attachment of the adjustment motor on the stiffening plate and the tooth engagement of the drive pinion in the toothing is reduced. The rigidity of the adjustment drive is thereby increased. Furthermore, a second stiffening plate can optionally be bolted to the second bearing ring on the blade side, which has a recess for the passage of the adjustment motor. The second stiffening plate further stiffens the blade connection surface and thus contributes to a uniformity of the forces introduced into the raceway system. The recess in the second stiffening plate still allows the installation space in the blade root to be used to accommodate the adjustment motor.

[0018] In other embodiments, the first bearing ring forms the inner ring of the bearing unit, and the gearing is formed on the inside in the region of the raceway system. These embodiments have the advantage that the rotor hub extension does not have to bridge the entire radial distance between the connection surface of the rotor hub and the connection surface of the rotor blade, but rather the radial width of the raceway system of the bearing unit also contributes to bridging the distance. For a given diameter ratio of blade root to hub connection surface, these embodiments have a smaller radial lever arm of the rotor hub extension. In these embodiments, the stiffening plate is preferably bolted to the second bearing ring on the blade side.

[0019] The rotor hub extension preferably has a generally conical shape, the diameter of which decreases from the raceway system to the hub-side end region. In particular, it is preferred if the rotor hub extension has an outer diameter at its hub-side fastening surface that is smaller than an inner diameter of the first bearing ring in the region of the raceway system. This achieves the technical advantage of being able to fasten the largest possible rotor blades to the smallest possible hub. The larger diameter of the raceway system compared to the outer diameter of the rotor hub extension at the hub-side fastening surface also increases the load-bearing capacity of the blade bearing, which has a positive effect on durability and service life.

[0020] The object is further achieved by a wind turbine comprising a tower, a nacelle, and a rotor rotatably mounted on the nacelle. The rotor comprises a hub and a plurality of rotor blades rotatably mounted on the hub, wherein at least one of the rotor blades is mounted on the hub by means of the bearing unit described above. The hub preferably has an annular stiffening means in a connection area for the bearing unit. The use of an annular stiffening means in the connection area of ​​the hub ensures accessibility to the drive components of the bearing unit. The annular stiffening means can, for example, be a cast-on stiffening ring or a stiffening plate with a sufficiently large central recess that allows access to the components of the adjustment drive.

[0021] Further advantageous embodiments can be found in the following description and the subclaims.

[0022] The invention is explained in more detail below with reference to the embodiments shown in the attached figures.

[0023] Brief description of the drawings

[0024] Fig. 1 shows schematically a wind turbine according to the invention, the rotor blades of which are mounted on the hub by means of bearing units according to the invention,

[0025] Fig. 2 shows schematically a partially sectioned, perspective view of a rotor hub with two bearing units according to the invention according to a first embodiment of the invention,

[0026] Fig. 3 and 4 show schematic, partially sectioned, perspective detail views of the bearing unit according to Fig. 2, and

[0027] Fig. 5 shows schematically a second embodiment of the bearing unit according to the invention, in which the first bearing ring forms the inner ring of the bearing unit.

[0028] Embodiments of the invention

[0029] In the various figures, identical parts are always provided with the same reference symbols and are therefore usually named or mentioned only once.

[0030] Fig. 1 shows a wind turbine 100 according to the invention. The wind turbine 100 comprises a tower 110, a nacelle 120, and a rotor 130 rotatably mounted on the nacelle 120. The rotor 130 comprises a hub 150 and a plurality of rotor blades 140 rotatably mounted on the hub 150. Typically, the rotor 130 comprises three rotor blades 140, as shown. The rotor blades 140 are rotatably mounted on the hub to enable power control of the wind turbine 100 in fluctuating wind conditions. Furthermore, it is possible to adjust the rotor blades 140 to the feathered position, i.e., in the wind direction, in order to minimize the power consumption of the rotor blades 140 and to decommission the wind turbine 100.

[0031] At least one of the rotor blades 140 is mounted on the hub 150 by means of a bearing unit 1 according to the invention. Preferably, all rotor blades 140 are mounted on the hub 150 by means of bearing units 1 according to the invention.

[0032] The bearing units 1 according to the invention and their fastening to the hub 150 are explained in more detail below with reference to Figures 2 to 5.

[0033] Fig. 2 to Fig. 4 show a first embodiment of a bearing unit 1 according to the invention, which is fastened to the hub 150 of a wind turbine. Fig. 2 shows a perspective, partially sectioned view of a hub 150 with two bearing units 1 fastened thereto. In a connection area C for the bearing unit 1, the hub 150 has an annular stiffening means 160. The annular stiffening means 160 is designed here as a cast-on stiffening ring. Such an annular stiffening means 160 allows access to the components of the bearing unit 1 from the interior of the hub 150 and thus simplifies assembly and maintenance work.

[0034] The first embodiment of the bearing unit 1 according to the invention for fastening and angularly adjusting a rotor blade to a hub 150 of a wind turbine, shown in Figures 2 to 4, comprises a first bearing ring 2 with first fastening holes 3 for fastening to the hub 150 and a second bearing ring 4 with second fastening holes 5 for fastening to the rotor blade 140 (see Figure 1). The second bearing ring 4 is arranged coaxially to the first bearing ring 2 and rotatable relative to the first bearing ring 2 about the common axis A.

[0035] The first bearing ring 2 is formed integrally with a rotor hub extension 10. The rotor hub extension 10 extends on the hub side in the axial direction A beyond the second bearing ring 4. The first fastening bores 3 are arranged in the hub-side end region E of the rotor hub extension 10. The rotor hub extension 10 is preferably conical and widens in diameter from the hub-side end region E to the blade-side fastening surface. It is particularly preferred if the rotor hub extension 10 has an outer diameter D on its hub-side fastening surface 22 that is smaller than an inner diameter d of the first bearing ring 2 in the region of the raceway system 6 (see Fig. 2).

[0036] The bearing unit 1 further comprises at least one row of rolling elements 7, 8 that can roll between the bearing rings (2, 4) in a raceway system 6. According to the illustrated embodiment, three rows of rolling elements are provided, in particular two axial roller rows 7 and one radial roller row 8. The rolling elements can be, for example, cylindrical rollers, tapered rollers, or balls. To simplify the assembly of the raceway system 6 with the rolling element rows, depending on the bearing design, it can be provided that the first bearing ring 2 and / or the second bearing ring 4 is formed in at least two parts, for example with a support ring 2'; 4' and a retaining ring 2"; 4".Although the invention is fundamentally applicable to all conceivable types of rolling elements 7, 8 and raceway systems 6, it is preferred if the bearing rings 2, 4, together with the raceway system 6 and the rolling elements 7, 8, form a three-row roller bearing assembly (as shown in the figures) or a double-row four-point contact ball bearing (not shown). Combinations of roller and ball raceways are also possible if necessary.

[0037] Finally, the bearing unit 1 comprises an adjustment drive 9, which is designed to adjust the angle of the two bearing rings 2, 4 relative to one another. The adjustment drive 9 comprises at least one electric adjustment motor 11, a shaft 12 driven by the adjustment motor 11, and a drive pinion 13 arranged on the shaft 12. The drive pinion 13 meshes with a toothing 14 formed on the inside of the first bearing ring 2. The toothing 14 is preferably provided over the entire circumference of the bearing unit 1. However, a toothing 14 that is only formed in segments on the inner circumference of the bearing unit 1 is also conceivable, in which case the center angle of the toothing segment(s) corresponds to the maximum adjustment angle of the adjustment drive 9. The toothing segments can, for example, have a center angle between 30° and 360°.

[0038] The electric variable pitch motor 11 is arranged on the blade side on a stiffening plate 15 mounted on the second bearing ring 4, which has an eccentric recess 16 through which the shaft 12 extends. Fastening means, such as a flange or a bolt circle (not shown), are provided on the stiffening plate 15 for fastening the electric variable pitch motor 11. Preferably, the variable pitch motor 11 extends in the axial direction A beyond the second bearing ring 4 on the blade side, thus utilizing the installation space available in the rotor blade 140. Accordingly, the variable pitch motor 11 preferably extends completely in the axial direction A in the region of the bearing unit 1 and, if applicable, the rotor blade 140.

[0039] Depending on the design of the wind turbine 100, the bearing unit 1 can also be equipped with several electric adjustment motors 11 of the same design, distributed around the circumference of the gearing 14. This can be particularly advantageous for wind turbines 100 in the multi-megawatt range, in order to better distribute the acting forces across the gearing.

[0040] Preferably, the adjustment drive 9 comprises a gear 17 interposed between the adjustment motor 11 and the shaft 12 to convert the motor speed to a preferred adjustment speed of the rotor blade 140. The adjustment motor 11 can be attached to the stiffening plate 15 by means of the gear 17.

[0041] As can also be seen from the first exemplary embodiment, it is an advantage of the invention that the stiffening plate 15, which serves to secure the adjustment motor 11, can also be used for the space-optimized arrangement of the motor control. Thus, it is preferably provided that a control unit 18 for controlling the electric adjustment motor 11 is arranged on the hub side of the stiffening plate 15. Likewise, a battery unit 19 for emergency operation of the adjustment motor 11 can preferably be arranged on the hub side of the stiffening plate 15. In addition to or as part of the control unit 18, a converter 23 can be arranged on the hub side of the stiffening plate 15. The control unit 18 and / or the battery unit 19 and / or the converter 23 preferably extend completely within the bearing unit 1 in the axial direction A.The interior of the hub 150 can thus preferably remain completely free of components for controlling the adjustment drive 9 and these above-mentioned components of the adjustment drive in the rotor hub extension can be mounted independently of the hub.

[0042] According to the first embodiment, the first bearing ring 2 forms the outer ring of the bearing unit 1, and the toothing 14 is formed in the hub-side end region E of the rotor hub extension 10. To achieve the highest possible rigidity of the adjustment drive 9, it is preferred that the stiffening plate 15 be screwed to the second bearing ring 4 on the hub side. This reduces the axial distance between the attachment of the adjustment motor 11 to the stiffening plate 15 and the tooth engagement of the drive pinion 13.

[0043] In addition, a second stiffening plate 20 can be screwed to the blade side of the second bearing ring 4, which has a recess 21 for the passage of the adjustment motor 11. The two stiffening plates 15, 20, together with the second bearing ring 4, form a sandwich-type structure, a particularly torsionally rigid construction for fastening the rotor blade 140 with a comparatively low weight, which has a favorable effect on the load introduction into the blade.

[0044] The first stiffening plate 15 and—if present—also the second stiffening plate 20 preferably have an opening 24 for maintenance work. The opening 24 is preferably sized so that a technician can climb through it into the interior of the blade. The opening 24 is preferably located centrally in the stiffening plate 15, 20.

[0045] As can be seen in particular from Fig. 4, the toothing 14 can be spaced apart from the raceway system 6 along the extension of the rotor hub extension 10 by a distance X that corresponds to at least half the axial extension Y of the second bearing ring 4. This sufficiently large spacing of the toothing 14 reliably protects the raceway system 6 from the introduction of excessively large adjustment forces that could damage the raceway system 6 and / or the rolling elements 7, 8. In the illustrated embodiment, the distance X even exceeds the axial extension Y of the second bearing ring 4.

[0046] Fig. 5 shows a second embodiment of the bearing unit 1 according to the invention. In contrast to the first embodiment, the first bearing ring 2 forms the inner ring of the bearing unit 1, and the toothing 14 is formed on the inside in the area of ​​the raceway system 6. Furthermore, the stiffening plate 15 is screwed to the second bearing ring 4 on the blade side.

[0047] Otherwise, the statements regarding the first embodiment shown in Figs. 2 to 4 apply accordingly to the second embodiment. According to an embodiment not shown, additional functionalities can also be integrated into the bearing unit via add-on components. For example, the bearing unit can include a grease pump for lubricating the raceway systems of the bearing unit. Alternatively or additionally, a locking device for locking the adjustment drive or the angle adjustment (a so-called pitch lock) can also be integrated into the bearing unit. These add-on components can also be mounted on one of the two stiffening plates.

[0048] Otherwise, the statements regarding the two embodiments according to Figs. 2 to 5 apply accordingly.

[0049] List of reference symbols

[0050] 1 storage unit

[0051] 2 first bearing ring

[0052] 2' support ring

[0053] 2" retaining ring

[0054] 3 first mounting holes

[0055] 4 second bearing ring

[0056] 4' support ring

[0057] 4" retaining ring

[0058] 5 second mounting holes

[0059] 6 Career system

[0060] 7, 8 rows of rolling elements

[0061] 9 Adjustment drive

[0062] 10 Rotor hub extension

[0063] 11 electric adjustment motor

[0064] 12 Wave

[0065] 13 drive pinions

[0066] 14 Gearing

[0067] 15 stiffening plate

[0068] 16 Recess

[0069] 17 gearboxes

[0070] 18 Control unit

[0071] 19 Battery unit

[0072] 20 second stiffening plate

[0073] 21 Recess in second stiffening plate

[0074] 22 Hub-side mounting surface of the rotor hub extension

[0075] 23 inverters

[0076] 24 Opening

[0077] 100 wind turbines

[0078] 110 Tower

[0079] 120 gondolas

[0080] 130 rotor

[0081] 140 rotor blade

[0082] 150 hub

[0083] 160 annular stiffener A axis of the bearing unit

[0084] C Connection area of ​​the hub d Inner diameter of the first bearing ring in the area of ​​the raceway system

[0085] D Outer diameter of the first bearing ring on the hub-side mounting surface

[0086] E hub-side end area of ​​the rotor hub extension

[0087] X distance

[0088] Y axial extension of the second bearing ring

Claims

PATENT CLAIMS 1. A bearing unit for fastening and angularly adjusting a rotor blade (140) to a hub (150) of a wind turbine (100), comprising a first bearing ring (2) with first fastening bores (3) for fastening to the hub (150), a second bearing ring (4) with second fastening bores (5) for fastening to the rotor blade (140), wherein the second bearing ring (4) is arranged coaxially to the first bearing ring (2) and rotatable relative to the first bearing ring (2) about the common axis (A), at least one row of rolling elements (7, 8) that can roll between the bearing rings in a raceway system (6), and an adjusting drive (9) that is configured for angularly adjusting the two bearing rings (2, 4) relative to one another, wherein the first bearing ring (2) is formed integrally with a rotor hub extension (10),which extends on the hub side in the axial direction (A) beyond the second bearing ring (4) and in whose hub-side end region (E) the first fastening bores (3) are arranged, characterized in that the adjusting drive (9) comprises at least one electric adjusting motor (11), a shaft (12) driven by the adjusting motor (11) and a drive pinion (13) arranged on the shaft (12) which meshes with a toothing (14) formed on the inside of the first bearing ring (2), wherein the adjusting motor (11) is arranged on the blade side on a stiffening plate (15) mounted on the second bearing ring (4) and the shaft (12) extends through an eccentrically arranged recess (16) in the stiffening plate (15).

2. Bearing unit according to claim 1, characterized in that the adjustment drive (9) comprises a gear (17) which is interposed between the adjustment motor (11) and the shaft (12).

3. Bearing unit according to claim 1 or 2, characterized in that a control unit (18) for controlling the adjusting motor (11) is arranged on the stiffening plate (15), preferably on the side facing the hub (150).

4. Bearing unit according to one of claims 1 to 3, characterized in that a battery unit (19) for emergency operation of the adjusting motor (11) is arranged on the stiffening plate (15), preferably on the side facing the hub.

5. Bearing unit according to one of claims 1 to 4, characterized in that the adjusting motor (11) extends in the axial direction (A) on the blade side beyond the second bearing ring (4).

6. Bearing unit according to one of claims 1 to 5, characterized in that the first bearing ring (2) forms the outer ring of the bearing unit (1) and the toothing (14) is formed in the hub-side end region (E) of the rotor hub extension (10).

7. Bearing unit according to claim 6, characterized in that the stiffening plate (15) is screwed to the second bearing ring (4) on the hub side.

8. Bearing unit according to claim 7, characterized in that a second stiffening plate (20) is screwed to the second bearing ring (4) on the blade side, which has a recess (21) for the passage of the adjusting motor (11).

9. Bearing unit according to one of claims 6 to 8, characterized in that the toothing (14) along the extension of the rotor hub extension (10) is spaced from the raceway system (6) by a distance (X) which corresponds to at least half the axial extension (Y) of the second bearing ring.

10. Bearing unit according to one of claims 1 to 5, characterized in that the first bearing ring (2) forms the inner ring of the bearing unit (1) and the toothing (14) is formed on the inside in the region of the raceway system (6).

11. Bearing unit according to claim 10, characterized in that the stiffening plate (15) is screwed to the second bearing ring (4) on the blade side.

12. Bearing unit according to one of claims 1 to 11, characterized in that the rotor hub extension (10) has on its hub-side fastening surface (22) an outer diameter (D) which is smaller than an inner diameter (d) of the first bearing ring (2) in the region of the raceway system (6).

13. Wind turbine (100) comprising a tower (110), a nacelle (120) and a rotor (130) rotatably mounted on the nacelle (120), wherein the rotor (130) comprises a hub (150) and a plurality of rotor blades (140) rotatably mounted on the hub (150), characterized in that at least one of the rotor blades (140) is mounted on the hub (150) by means of a bearing unit (1) according to one of claims 1 to 12.

14. Wind turbine (100) according to claim 13, characterized in that the hub (150) has an annular stiffening means (160) in a connection region (C) for the bearing unit (1).

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