Device for fastening a rotor blade to a hub body, and multi-part hub assembly for a wind turbine

Abstract

The invention relates to a device (1) for fastening a rotor blade (140) to a hub body (13) of a wind turbine (100), said device comprising a blade-side extender bearing unit (2) having a first bearing ring (3) with a first bolt circle (4) for fastening to the hub body (13), and a second bearing ring (5) for fastening to the rotor blade (140), the second bearing ring (5) being arranged coaxially to the first bearing ring (3) so as to be rotatable about the common bearing axis (A), the first bearing ring (3) being integrally formed with a rotor hub extension (9) which extends on the hub side in the direction of the bearing axis (A) beyond the second bearing ring (5), with the first bolt circle (4) being arranged in the hub-side end region (E) of said rotor hub extension, the device (1) also comprising a hub-side extender bearing unit (10) which is plate-shaped and has a second bolt circle (11), the first bolt circle (4) being aligned with the second bolt circle (11) for joint fastening to the hub body (13). The invention also relates to a multi-part hub assembly (150) which is held together by means of at least one fastening device (1) according to the invention.

Description

[0001] Device for fastening a rotor blade to a hub body and multi-part hub assembly for a wind turbine

[0002] State of the art

[0003] The invention relates to a device for fastening a rotor blade to a hub body according to the preamble of claim 1, as well as to a multi-part hub arrangement for a wind turbine according to the preamble of claim 6.

[0004] The rotor blades of wind turbines are attached to the hub using slewing bearings. These slewing bearings allow the adjustment of the rotor blades' angle of attack to the wind, which is necessary, among other things, for controlling the turbine's power output.

[0005] Hub bodies are currently typically constructed as one-piece castings. Because the hub body alone can only partially meet the ever-increasing rigidity requirements of the bearing-side connection surfaces as wind turbines grow, or would have to be designed to be increasingly massive and heavy, it is known that additional, separately manufactured components, such as stiffening elements mounted on the blade connection or hub connection side, can be bolted to the bearing-side attachments for targeted, local stiffening of the blade and / or rotor bearing connection surfaces. These stiffening elements can, for example, be simplified as plates with a central bore in the middle to allow access to the components adjacent to the bearing, i.e. the hub or blade, for assembly and maintenance purposes.The known plates primarily serve to increase the torsional rigidity of the connecting surfaces in order to relieve the load on the connected slewing bearings with regard to the induced structural deformations.

[0006] The current design principle with a one-piece hub is reaching its limits as wind turbines continue to grow in power and size. These limitations are, on the one hand, of a manufacturing nature. Casting such large hub bodies in one piece with the required precision and subsequently machining them with the required high level of detail requires considerable manufacturing effort, particularly due to the expected hub sizes and weights. On the other hand, the entire wind turbine manufacturing industry is also predictably reaching availability limits, because the number of foundries worldwide capable of producing such large hub bodies in one piece represents a significant obstacle to the expected expansion of wind turbines.Finally, there are also expected logistical restrictions due to hub transport, particularly for onshore wind turbines, since hub bodies with dimensions of more than 4 meters can no longer be transported to the site by road without significant additional costs as a result of increased transport and traffic management logistics, due to bridge heights, tunnel diameters, etc. In the onshore sector, it is therefore to be expected that for turbine outputs of >7 - 8 MW and above, one-piece hub bodies based on a conventional design of the overall hub-blade bearing system can no longer be transported by road in a cost-effective and therefore practical manner.

[0007] Therefore, some concepts are already known from the state of the art according to which the hub body can be divided into several smaller parts.

[0008] For example, EP 2 837 820 B1 describes a segmented wind turbine hub, wherein the segments are formed as hollow bodies and each comprise two structurally designed regions inside the hub with connecting surfaces for connecting the segment to two other segments. Each region for connecting the segments has a substantially closed surface that rests on the corresponding surface of the adjacent segment and is fastened thereto with bolts, rivets, or by welding. The symmetrical segmentation here takes place specifically between the blade bearing connecting surfaces, so that the blade bearing ring structurally performs no function in the mechanical fixation of the adjacent hub segments.

[0009] US 8449263 B2 also shows a segmented rotor hub, which is designed as a double-shell rotor hub with an inner hub and a hub shell, each of which is segmented and bolted or riveted together via flanges at the segment joints. The inner hub and hub shell are connected via support struts. Here, the segmentation also takes place between the blade bearing connection surfaces.

[0010] The disadvantage of the two aforementioned patents is that the hub segments, and in particular the structural elements for fixing adjacent hub segments, are complicated to manufacture and that a considerable amount of effort is required to screw the hub segments together in addition to the assembly of the blade bearings that is already required.

[0011] From DE 10 2011 052 668 B4, a device for fastening a rotor blade to a hub body according to the preamble of claim 1, as well as a hub arrangement for a wind turbine according to the preamble of claim 5, are known. DE 10 2011 052 668 B4 describes another segmented hub for a wind turbine. The segments have at least one side that rests against the side of an adjacent segment and extends from an outer circumference of the hub to a central region of the hub. The segments are connected to a front plate that is mounted on the side surfaces of the segments facing in a direction away from the nacelle, i.e., opposite the wind direction. Each rotor blade is attached to the hub via an additional component, the so-called connecting hub, which has two concentric, circular arrangements of bolt holes.The outer bolt circle is intended for connection to the hub segments and the inner bolt circle is intended for mounting rotor blade bearings.

[0012] A disadvantage is that the connecting hubs must be designed to transfer the load from the blade-side connection diameter to another hub-side connection diameter, and the two bolt circles result in significantly increased manufacturing and assembly costs. Another disadvantage is that the connecting hub only allows the assembly of rotor blade bearings, and therefore rotor blades, that have a smaller diameter than the larger of the two bolt circles. This means that the full potential of the blade bearing and therefore the blade root diameter cannot be exploited in relation to the hub size, which, in relation to the smaller blade bearing diameter, leads to a reduced load-bearing capacity and service life of the blade bearing. Deriving from the smaller blade root diameter, this restricts the overall rotor diameter and thus the achievable yield of the wind turbine.For a hub of the same size, only a comparatively small rotor can be supported by the segmented hub. In the known design, however, such a connecting hub, which brings about a radial reduction in the maximum blade root diameter, is necessary because conventional blade bearings require a continuous, i.e. unsegmented, connection surface. In addition, access to the two bolt hole circles on the connecting hub - one for fastening the connecting hub on the hub side and one for fastening the connecting hub on the blade side - must be guaranteed at height for both assembly and maintenance purposes. The connecting hub has the function of transmitting the normal and thrust forces at the abutting surfaces of adjacent hub segments in order to protect the stationary rings of the blade bearings from additional transmission of additional loads resulting from the hub segmentation.

[0013] Disclosure of the invention

[0014] The object of the invention is therefore to provide a device for fastening a rotor blade to a hub body, as well as a multi-part hub arrangement for a wind turbine, which can be easily manufactured, transported and assembled on site, and which offers greater flexibility in terms of the connection diameter of the blade bearing and the rotor blade.

[0015] This object is achieved by a device for fastening a rotor blade to a hub body having the features of claim 1 and a multi-part hub arrangement having the features of claim 5.

[0016] This creates a device for fastening a rotor blade to a hub body of a wind turbine, which device comprises a blade-side extender bearing unit and a hub-side extender bearing unit. The blade-side extender bearing unit comprises a first bearing ring with a first bolt circle for fastening to the hub body, and a second bearing ring for fastening to the rotor blade. The second bearing ring is arranged coaxially to the first bearing ring so as to be rotatable about the common bearing axis. The hub-side extender bearing unit is plate-shaped and has a second bolt circle. According to the invention, the first bearing ring is formed with a rotor hub extension which extends on the hub side in the direction of the bearing axis beyond the second bearing ring and in the hub-side end region of which the first bolt circle is arranged.The second bolt circle of the hub-side extender bearing unit is aligned with the first bolt circle of the blade-side extender bearing unit for joint attachment to the hub body.

[0017] The at least two-part device according to the invention for fastening a rotor blade to a hub body enables the attachment of the rotor blade to a segmented hub body with screw connections that extend through the first and second bolt circles and thus simultaneously fasten the blade-side and hub-side extender bearing units to the hub body—preferably symmetrically segmented in the blade bearing connection surface. This effectively reduces the number of screws required, significantly reducing on-site assembly effort and the costs for machining the individual components.

[0018] This simplified assembly is made possible by the inventive separate design of the blade-side and hub-side extender bearing units. The hub-side extender bearing unit can also absorb the stresses occurring in the joint between hub body segments, thus relieving the load on the blade-side extender bearing unit. The rotor hub extension integrated into the blade-side extender bearing unit is also designed, in its end region for connection to the hub, to absorb the additional stresses resulting from the segmentation of the hub body. In this way, deformation of the bearing ring arranged on the blade-side extender bearing unit, which could lead to a deterioration of the blade bearing, is specifically avoided.

[0019] The hub-side extender bearing unit preferably has a plate thickness that is at least 20% of the axial wall thickness of the rotor hub extension in its hub-side end region. Particularly preferably, the plate thickness is at least 50% or even at least 70% of the wall thickness of the rotor hub extension in its hub-side end region. Such plate thicknesses significantly exceed the thicknesses of plate-like stiffening means for stiffening blade connection surfaces of one-piece rotor hubs, which only have to absorb torsional stresses on the blade connection surfaces. With the aforementioned preferred plate thicknesses, the hub-side extender bearing unit, on the other hand, is designed for stresses of the same order of magnitude as the stresses introduced into the hub body by the entire rotor blade via the rotor hub extension.Such hub-side extender bearing units are therefore particularly well suited to absorbing the additional thrust forces in the segment joint that occur with a split hub.

[0020] In preferred embodiments, the hub-side extender bearing unit, in addition to the second bolt circle, has fastening means for temporarily or permanently fixing the hub-side extender bearing unit to the hub body. The additional fastening means allow for step-by-step assembly of the device to a multi-part hub body. The fastening means can be formed, for example, by fastening holes, form-fitting mounting elements, or the like. By fixing the hub-side extender bearing unit to the hub body via the fastening means, for example, by fixing elements engaging in the fastening holes, several hub body segments can be easily and accurately positioned with respect to the hub-side extender bearing unit and relative to one another.This simplifies the assembly of the hub segments and the subsequent assembly of the blade-side extender bearing unit to the already assembled hub body and, in particular, reduces possible errors during on-site assembly.

[0021] Preferably, at least one row of rolling elements can be provided between the first and second bearing rings of the blade-side extender bearing unit, said rolling elements having a rolling element diameter, wherein the rotor hub extension extends beyond the second bearing ring in the direction of the bearing axis by at least three times the rolling element diameter of the row of the largest rolling elements. The rolling element diameter of the rolling element row with the largest diameter is a measure of the maximum forces that can be transmitted by the rolling bearing. The tensile and thrust forces occurring at the joint on a multi-part, segmented hub are directly related to the forces introduced by the rotor blades via the blade bearings.It has been found that the raceway system of the blade bearing is particularly well protected against deformation due to the forces at the segment joints of the hub if the rotor hub extension extends in the direction of the bearing axis beyond the second bearing ring by at least 3 times the largest rolling element diameter.

[0022] In further preferred embodiments, the hub-side extender bearing unit can comprise at least two parts, each containing a circumferential section of the second bolt circle. The multi-part design of the hub-side extender bearing unit further reduces the number of components the size of the blade diameter. In these embodiments, the blade-side extender bearing unit can be the only component whose dimensions reach or exceed the diameter of the rotor blade to be mounted. The object is further achieved by a multi-part hub arrangement for a wind turbine. The hub arrangement comprises a hub body with fastening means for fastening the hub arrangement to a nacelle of the wind turbine and at least one third bolt circle for fastening a rotor blade of the wind turbine.The hub body comprises at least two hub body segments, each of which forms a circumferential portion of the third bolt circle. The hub body segments are arranged such that the circumferential portions together form the third bolt circle. The hub assembly further comprises a fastening device according to the invention as described above, wherein the third bolt circle is aligned with the first bolt circle and the second bolt circle of the fastening device. The fastening device is fastened to the hub body with a plurality of screws, each of which extends through the first, second, and third bolt circles.

[0023] By bolting the hub body segments together with the multi-part fastening device across the first, second, and third bolt circles, a frictional connection is created between the hub body segments and the fastening device, which transfers the forces occurring at the joint between the hub body segments via the fastening device. The aligned arrangement of all three bolt circles allows for simplified assembly with a single row of screws.

[0024] The multi-part hub assembly according to the invention significantly reduces transport volume to the wind turbine construction site compared to a single-piece hub, while simultaneously enabling simple on-site assembly using screw connections. Furthermore, the hub body segments can be manufactured with less effort than a single-piece hub, thus mitigating anticipated bottlenecks in the production of large structural components.

[0025] In some preferred embodiments, the third bolt circle is formed as through holes arranged in a radial flange of the hub body. The radial flange of the hub body simultaneously forms both a stiffening element for the respective hub segment and an enlarged bearing surface for the frictional engagement with the fastening device. In these embodiments, the hub-side extender bearing unit is particularly preferably arranged on the inside of the hub and the blade-side extender bearing unit is arranged on the outside of the hub. The sandwich-like arrangement and screw connection of the radial flanges of adjacent hub segments between the blade-side and hub-side extender bearing units further increases the area effective for the frictional engagement, since both axial surfaces of the flange are utilized for the transmission of thrust and frictional forces.Furthermore, in these embodiments, the bending stress of the screw connection that connects both extender bearing units to the hub segments can be reduced.

[0026] In other preferred embodiments, the third bolt circle is formed as blind holes in the hub body, with the hub-side extender bearing unit and the blade-side extender bearing unit being arranged on the outside of the hub body. These embodiments are characterized by a particularly simple casting mold for the hub body segments, which, moreover, are equipped with only one finely machined support surface for the fastening device.

[0027] Furthermore, it is advantageous if the circumferential sections of the second bolt circle formed on the parts of the hub-side extender bearing unit are each arranged so as to overlap at least two circumferential sections of the third bolt circle formed on the hub body segments. In this way, despite the at least two-part design of the hub body and the hub-side extender bearing unit, it is possible to transmit the forces occurring at the joint between the hub body segments via the hub-side extender bearing unit.

[0028] Finally, it is advantageous if the hub body segments are connected to each other on the upwind and / or downwind sides with at least one stiffening ring. Stiffening rings, especially seamless rolled stiffening rings, are designed to absorb particularly high tensile stresses. Compared to a bolted-on central plate, a stiffening ring also absorbs the tensile forces in the radial direction further outward and thus closer to the blade roots, where the loads are transferred into the hub body.

[0029] Further advantageous embodiments can be found in the following description and the dependent claims. The invention is explained in more detail below with reference to the exemplary embodiments illustrated in the accompanying drawings.

[0030] Brief description of the drawings

[0031] Fig. 1 shows schematically a wind turbine whose rotor blades are mounted on the hub body by means of fastening devices according to the invention,

[0032] Fig. 2 shows schematically a hub arrangement according to the invention with a three-part hub body and three fastening devices according to the invention,

[0033] Fig. 3 shows schematically in a partially sectioned, perspective view parts of the hub arrangement according to Fig. 2,

[0034] Fig. 4 and 5 show schematically in sectional representations the interaction of fastening device and hub body segments according to the embodiment according to Fig. 1 to 3,

[0035] Fig. 6 shows schematically in a sectional view the interaction of the fastening device and hub body segments according to a second embodiment of the invention, and

[0036] Fig. 7 shows schematically the second embodiment according to Fig. 6 in an equipment variant with an electric blade adjustment drive.

[0037] Embodiments of the invention

[0038] In the various figures, identical parts are always provided with the same reference symbols and are therefore usually named or mentioned only once.

[0039] 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 multi-part hub assembly 150 and a plurality of rotor blades 140 rotatably attached to the hub assembly 150. Typically, the rotor 130 comprises three rotor blades 140, as shown. The rotor blades 140 are rotatably mounted on the hub assembly 150 to enable power control of the wind turbine 100 under 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.

[0040] At least one of the rotor blades 140 is mounted on the hub assembly 150 by means of a fastening device 1 according to the invention. Preferably, all rotor blades 140 are mounted on the hub 150 by means of fastening devices 1 according to the invention.

[0041] The hub assemblies 150 according to the invention with the fastening devices 1 used therein for fastening the rotor blades 140 to the hub body are explained in more detail below with reference to Figures 2 to 7.

[0042] Figs. 2 to 5 show a first embodiment of a multi-part hub assembly 150 according to the invention for a wind turbine 100 (see Fig. 1). The hub assembly 150 comprises a hub body 13 with fastening means 22 for fastening the hub assembly 150 to the nacelle 120 of the wind turbine 100 and preferably with three third bolt circles 14 for fastening a respective rotor blade 140 of the wind turbine 100.

[0043] The hub body 13 preferably comprises three hub body segments 13', 13", 13'", on each of which a circumferential section 14', 14" of two of the three third bolt circles 14 is formed. The circumferential sections 14', 14" are arranged such that together they form the third bolt circles 14. In other words, the hub body 13 is divided into hub body segments 13', 13", 13'", wherein the joints of the hub body segments 13', 13", 13'" are each located in the blade connection surfaces defined by the third bolt circles 14.

[0044] The hub arrangement 150 further comprises a fastening device 1 according to the invention for each of the third bolt circles 14, which is explained in more detail below with reference to Figs. 4 and 5.

[0045] The fastening device 1 for fastening the rotor blade 140 to the hub body 13 of the wind turbine 100 comprises a blade-side extender bearing unit 2 and a hub-side extender bearing unit 10. The blade-side extender bearing unit 2 has a first bearing ring 3 with a first bolt circle 4 for fastening to the hub body 13 and a second bearing ring 5 for fastening to the rotor blade 140. The second bearing ring 5 is arranged coaxially to the first bearing ring 3 and can be rotated about the common bearing axis A.

[0046] The first bearing ring 3 is formed with a rotor hub extension 9, which extends beyond the second bearing ring 5 on the hub side in the direction of the bearing axis A. The first bolt circle 4 is arranged in a hub-side end region E of the rotor hub extension 9. The hub-side end region E is preferably formed as a radially extending flange.

[0047] The rotor hub extension can be substantially cylindrical or tapered toward or tapered from the rotor blade. This allows rotor blades 140 with different blade root diameters to be mounted on a standardized hub body 13. The fastening device 1 according to the invention thus functions as an adapter between standardized components of a modular system.

[0048] The figures show preferred embodiments with a conical extension of the rotor hub extension 9 toward the rotor blade. Such a conical extension has the advantage that, with the same size of the hub body 13, larger blade root diameters and thus longer rotor blades 140 can be mounted, enabling wind turbines with higher power.

[0049] The hub-side extender bearing unit 10 is plate-shaped and has a second bolt circle 11. The plate-shaped hub-side extender bearing unit can have a central opening through which the interior of the rotor blade 140 (see Fig. 1) is accessible from the hub body 13. Plate-shaped in the sense of this disclosure means that the radial extent of the hub-side extender bearing unit 10 is at least three times, preferably at least five times, its plate thickness D.

[0050] The plate thickness D of the hub-side extender bearing unit 10 is preferably at least 20% of the axial wall thickness W of the rotor hub extension 9 in its hub-side end region E. In some embodiments, the plate thickness D of the hub-side extender bearing unit 10 can also preferably be at least 50% or even at least 70% of the axial wall thickness W of the rotor hub extension 9 in its hub-side end region E in order to achieve additional stabilization of the segmented hub body.

[0051] According to the invention, the second bolt circle 11 is aligned with the first bolt circle 4 for joint attachment to the hub body 13. The third bolt circle 14 is also aligned with the first bolt circle 4 and the second bolt circle 11. The fastening device 1 is thus to be attached to the hub body 13 with a plurality of screws 15, each of which extends through the first bolt circle 4, the second bolt circle 11, and the third bolt circle 14.

[0052] Also encompassed by the invention are embodiments (not shown) in which at least a second, radially offset set of three mutually aligned bolt circles is provided in the hub-side and blade-side extender bearing units, as well as the hub body. The additional row of bolts can increase the transfer of loads via frictional engagement and the surface area for clamping the adjacent hub body segments between the blade-side and hub-side extender bearing units.

[0053] As can be seen in particular in Fig. 5, the hub-side extender bearing unit 10 can have, in addition to the second bolt circle 11, fastening means 12 for temporarily or permanently fixing the hub-side extender bearing unit 10 to the hub body 13. In a first step of assembly, the hub-side extender bearing unit 10 is fastened to the hub body segments 13', 13" via the fastening means 12 so that they are correctly positioned relative to one another. However, the type and number of fastening means 12 are not sufficient to absorb the loads in the segment joint during operation. Rather, they are aids to simplify fail-safe assembly. Centering devices and / or form-fitting assembly aids for the clear assignment and positioning of the parts can be provided as further aids for fail-safe assembly. This allows the assembly sequence on site to be optimized and its complexity reduced.

[0054] The first bearing ring 3 and the second bearing ring 5 can, for example, be designed as a plain bearing with sliding pads. However, in addition to or as an alternative to the sliding pads, at least one row of rolling elements 6, 7, 8, which can roll between the bearing rings 3, 5 and have a largest rolling element diameter WD, is preferably provided. The rolling elements 6, 7, 8 can be, for example, balls, cylindrical rollers, or tapered rollers. The rotor hub extension 9 extends in the direction of the bearing axis A beyond the second bearing ring 5 by at least 3 times, more preferably at least 5 times, the largest rolling element diameter WD of the row of largest rolling elements 7, 8.Due to the axial extension of the rotor hub extension 9, the rotor hub extension 9 has additional rigidity compared to a conventional blade bearing ring, which allows it to absorb the forces occurring in the segment joint of the hub body segments and to limit deformations of the raceway system to a tolerable level.

[0055] As shown in Figures 2 to 7, the first and second bearing rings 3, 5 can, for example, form a three-row roller bearing assembly. Alternatively, other bearing designs are also conceivable, such as a double-tapered roller bearing or a double-row angular contact ball bearing. The first and / or second bearing rings 3, 5 can be subdivided in the axial direction to simplify assembly of the bearing. In the exemplary embodiments shown in Figures 2 to 7, the outer ring 3 is subdivided in the axial direction A. However, embodiments in which the inner ring is subdivided in the axial direction A or in which there is no subdivision in the axial direction A at all are also conceivable.

[0056] As shown in particular in Fig. 3, the hub-side extender bearing unit 10 preferably comprises at least two parts 10', 10", each containing a circumferential section 1T, 11" of the second bolt circle 11. The circumferential sections 1T, 11" of the second bolt circle 11 formed on the parts 10', 10" of the hub-side extender bearing unit 10 are then each arranged to overlap at least two circumferential sections 14', 14" of the third bolt circle 14 formed on the hub body segments 13', 13".

[0057] In addition, the hub body segments 13', 13" can be connected to one another on the upwind side and / or the downwind side by means of at least one stiffening ring 17, 18, 19. Preferably, as shown in Fig. 3, two stiffening rings 17, 18 are used at least on the upwind side, which sandwich a flange 23 formed on the hub body segments 13', 13" and are penetrated by a row of screw connections. On the downwind side, the fastening means 22 are preferably also designed as a flange with a bolt circle, wherein the stiffening ring 19 is preferably arranged on the inside of the hub body 13. In the assembled state, the flange 22 is then also sandwiched between the stiffening ring 19 and the connecting component of the nacelle 120, usually a bearing ring of a rotor bearing or an end flange of a rotor shaft.In this sense, a stiffening ring on the downwind side can also be advantageously structurally integrated into the rotatable bearing ring of the rotor bearing or the rotor shaft by a correspondingly more solid design of the rotor bearing ring or rotor shaft. The stiffening rings 17, 18, 19 are preferably seamless rolled rings. The stiffening rings 17, 18, 19 can also be segmented, with the ring segment boundaries each overlapping the joints of the hub body segments 13', 13".

[0058] In the first embodiment shown in Figs. 2 to 5, the third bolt circle 14 is formed as through holes arranged in a radial flange 16 of the hub body 13. The hub-side extender bearing unit 10 is arranged on the inside of the hub flange 16, and the blade-side extender bearing unit 2 is arranged on the outside of the hub flange 16.

[0059] Fig. 6 shows a second embodiment of the invention. It differs from the first embodiment shown in Figs. 2 to 5 in that the third bolt circle 14 is formed as blind holes in the hub body 13. Both the hub-side extender bearing unit 10 and the blade-side extender bearing unit 2 are arranged on the outside of the hub body 13.

[0060] Otherwise, the statements regarding the first embodiment according to Figs. 2 to 5 apply accordingly to the second embodiment.

[0061] Fig. 7 shows an equipment variant of the second exemplary embodiment with an electric adjustment drive 20. The adjustment drive 20 is integrated into the blade-side extender bearing unit 2. For this purpose, the adjustment drive 20 is mounted on a stiffening plate 21, which in turn is fastened to the second bearing ring 5 of the blade-side extender bearing unit 2. The drive pinion of the adjustment drive 20 engages with a toothing in the hub-side end region E of the rotor hub extension 9. In this way, an adjustment of the pitch angle of the connected rotor blade 140 can be effected. The integration of the adjustment drive 20 into the fastening device 1 according to the invention has the advantage that the drive 20 can already be pre-assembled and tested in the factory and assembly in the field is limited to simple screw connections for assembling the hub. A separate supply line for the hub and blade bearing unit including the adjustment drive is also possible.Instead of a single adjustment drive 20, several adjustment drives 20 can be provided, distributed over the circumference of the fastening device 1.

[0062] The equipment variant with an integrated adjustment drive 20 is shown in Fig. 7 as an example for the second embodiment. Similarly, the fastening device according to the first embodiment shown in Figs. 2 to 5 can also be equipped with an integrated adjustment drive 20.

[0063] List of reference symbols

[0064] 1 fastening device

[0065] 2 blade-side extender bearing units

[0066] 3 first bearing ring

[0067] 4 first bolt circle

[0068] 5 second bearing ring

[0069] 6, 7, 8 rows of rolling elements

[0070] 9 Rotor hub extension

[0071] 10 hub-side extender bearing unit

[0072] 10', 10“ parts of the hub-side extender bearing unit

[0073] 11 second bolt circle

[0074] 1 T, 11" circumferential sections of the second bolt circle

[0075] 12 fasteners

[0076] 13 Hub body

[0077] 13', 13", 13'" hub body segments

[0078] 14 third bolt circle

[0079] 14', 14" circumferential sections of the third bolt circle

[0080] 15 screws

[0081] 16 flange

[0082] 17, 18, 19 stiffening ring

[0083] 20 Adjustment drive

[0084] 21 Stiffening plate

[0085] 22 fasteners

[0086] 23 Flange

[0087] 100 wind turbines

[0088] 110 Tower

[0089] 120 gondolas

[0090] 130 rotor

[0091] 140 rotor blades

[0092] 150 Multi-piece hub assembly

[0093] A bearing axis

[0094] E Hub-side end area of ​​the rotor hub extension D Plate thickness of the hub-side extender bearing unit

[0095] W Wall thickness of the rotor hub extension

[0096] WD rolling element diameter

Claims

PATENT CLAIMS 1. A device for fastening a rotor blade (140) to a hub body (13) of a wind turbine (100), comprising a blade-side extender bearing unit (2) comprising a first bearing ring (3) with a first hole circle (4) for fastening to the hub body (13), and a second bearing ring (5) for fastening to the rotor blade (140), wherein the second bearing ring (5) is arranged coaxially to the first bearing ring (3) so as to be rotatable about the common bearing axis (A), and a hub-side extender bearing unit (10) which is plate-shaped and has a second hole circle (11), characterized in that the first bearing ring (3) is formed with a rotor hub extension (9) which extends on the hub side in the direction of the bearing axis (A) beyond the second bearing ring (5) and in the hub-side end region (E) of which the first hole circle (4) is arranged,wherein the second bolt circle (11) is aligned with the first bolt circle (4) for joint attachment to the hub body (13).

2. Device according to claim 1, characterized in that the hub-side extender bearing unit (10) has a plate thickness (D) which is at least 20%, preferably at least 50% and particularly preferably at least 70% of an axial wall thickness (W) of the rotor hub extension (9) in its hub-side end region (E).

3. Device according to claim 1 or 2, characterized in that the hub-side extender bearing unit (10) has, in addition to the second bolt circle (11), fastening means (12) for a temporary or permanent fixation of the hub-side extender bearing unit (10) to the hub body (13).

4. Device according to one of claims 1 to 3, characterized in that at least one row of rolling elements (6, 7, 8) which can roll between the bearing rings (3, 5) are provided, which have a rolling element diameter (WD), and the rotor hub extension in the direction of the bearing axis (A) extends at least 3 times of the rolling element diameter (WD) of the row of the largest rolling elements (7, 8) extends beyond the second bearing ring (5).

5. Device according to one of claims 1 to 4, characterized in that the hub-side extender bearing unit (10) comprises at least two parts (10', 10"), each containing a circumferential section (1 T, 11") of the second bolt circle (11).

6. A multi-part hub assembly for a wind turbine (100), comprising a hub body (13) with fastening means (22) for fastening the hub assembly (150) to a nacelle (120) of the wind turbine (100) and at least one third bolt circle (14) for fastening a rotor blade (140) of the wind turbine (100), wherein the hub body (13) comprises at least two hub body segments (13', 13", 13'"), on each of which a circumferential section (14', 14") of the third bolt circle (14) is formed and which are arranged such that the circumferential sections (14', 14") together form the third bolt circle (14), characterized in that the hub assembly (150) further comprises a fastening device (1) according to one of claims 1 to 5, wherein the third bolt circle (14) is connected to the first bolt circle (4) and the second bolt circle (11) aligned and the fastening device (1) is fastened to the hub body (13) with a plurality of screws (15),which each extend through the first (4), second (11) and third hole circle (14).

7. Multi-part hub arrangement according to claim 6, characterized in that the third bolt circle (14) is designed as through holes which are arranged in a radial flange (16) of the hub body (13).

8. Multi-part hub arrangement according to claim 7, characterized in that the hub-side extender bearing unit (10) is arranged on the inside of the hub of the flange (16) and the blade-side extender bearing unit (2) is arranged on the outside of the hub of the flange (16).

9. Multi-part hub arrangement according to claim 6, characterized in that the third bolt circle (14) is designed as blind holes in the hub body (13), wherein the hub-side extender bearing unit (10) and the blade-side extender bearing unit (2) are arranged on the outside of the hub body (13).

10. Multi-part hub arrangement according to one of claims 6 to 9 with a fastening device (1) according to claim 5, characterized in that the circumferential sections (11', 11") of the second bolt circle (11) formed on the parts (10', 10") of the hub-side extender bearing unit (10) are each arranged to overlap at least two circumferential sections (14', 14") of the third bolt circle (14) formed on the hub body segments (13', 13").

11. Multi-part hub arrangement according to one of claims 6 to 10, characterized in that the hub body segments (13', 13") on the windward side and / or the leeward side are connected to one another by means of at least one stiffening ring (17, 18, 19).

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