Fastening system, wind turbine and method for dismantling a bearing

Abstract

The invention relates to a fastening system for attaching a drive train of a wind turbine (10) to a nacelle (20) of the wind turbine (10). The fastening system comprises a rotor bearing housing (40), a stationary component, and a first bearing (18). The first bearing (18) is mounted in the rotor bearing housing (40) for rotatable support of a rotor shaft (16) of the drive train. The rotor bearing housing (40) is further configured for attachment to a machine bed (42) of the nacelle (20). The fastening system is designed to fix the rotor shaft (16) to the stationary component for removal of the first bearing (18). The invention also relates to a wind turbine (10) and a method for removing a first bearing (18) from a rotor bearing housing (40) of a wind turbine (10).

Description

The present invention relates to a fastening system for a drive train of a wind turbine. The invention also relates to a wind turbine and a method for disassembling a bearing. State of the art Wind turbines are used to generate electricity from wind energy. For this purpose, wind turbines have a rotor. The rotor's rotational speed is transmitted by a rotor shaft to a gearbox. The gearbox then converts the rotor shaft's rotational speed into a suitable rotational speed to drive a generator. The wind turbine's drive train must be supported within the nacelle. This mounting can be very complex and require many parts. Furthermore, maintenance and replacement of individual drive train components can be very time-consuming, depending on the mounting solution. For example, it may be necessary to first dismantle the wind turbine's rotor before the rotor shaft bearings can be replaced. This may require a crane, which is a very labor-intensive process.For example, in the case of offshore wind turbines, a special ship has to be called in, which may only be available after a considerable delay. Description of the invention A first aspect concerns the mounting system for a wind turbine's drive train to the nacelle. The nacelle may have a machine bed. The wind turbine may have a tower on which the nacelle is mounted. The tower extends, for example, vertically. The nacelle may be mounted on the tower in a rotatable or non-rotatable manner. The nacelle may be located on the top of the tower. The tower may be hollow. The tower may taper towards its top. The tower may be constructed from several stacked tower sections. The tower may be made of steel and, alternatively or additionally, concrete. The drivetrain can include a rotor shaft, a gearbox, and a generator. Additionally, the drivetrain or the wind turbine can include a rotor. The wind turbine includes the drivetrain. Parts of the drivetrain can form part of the mounting system. The rotor can drive the generator via the gearbox to produce electrical energy. The rotor can be connected to the gearbox via the rotor shaft. The rotor can be mounted to the nacelle via the rotor shaft. The rotor, gearbox, and generator can be attached to a nacelle of the wind turbine, for example, together by a main bearing. The rotor can have, for example, a horizontal or a vertical axis of rotation. The rotor can have, for example, two, three, four, or more rotor blades, which are connected to the rotor shaft via a hub. The drivetrain can optionally include a brake. The mounting system includes a rotor bearing housing. At least one first bearing for rotatably supporting the rotor shaft of the drive train is mounted in the rotor bearing housing. A second bearing for rotatably supporting the rotor shaft may also be arranged in the rotor bearing housing. If only the first bearing is provided, the rotor shaft may be supported by another bearing in a different component of the drive train, such as a gearbox housing or a generator housing. This bearing may also be referred to as the second bearing. If two bearings are provided in the rotor bearing housing, the mounting system and the drive train may be free of further bearings for the rotor shaft in other components of the drive train. The bearings may be designed, for example, as rolling bearings. Suitable bearings include tapered roller bearings. The bearings may have an outer ring and an inner ring, with rolling elements arranged radially between them.The inner ring of at least the first bearing can be mounted on the rotor shaft. The outer ring of at least the first bearing can be mounted in a seat on the inside of the rotor shaft housing. The inner ring, and alternatively or additionally the outer ring, can be secured by an interference fit. Alternatively or additionally, axial retention, for example with a clamping element, can be provided to secure the respective rings. The rotor bearing housing can be, for example, a casting or forging. The rotor bearing housing can be a single piece or a multi-piece design. The rotor bearing housing is designed for attachment to the nacelle's machine bed. The machine bed can be, for example, a forged or cast part. The machine bed may have interfaces for attaching the drive train, such as bearing surfaces for the rotor bearing housing. The rotor bearing housing can be a separate component from the machine bed or formed integrally with it. The rotor bearing housing can be bolted or riveted to the machine bed, for example. The rotor bearing housing and the first bearing, as well as the optional second bearing within the rotor bearing housing, can form a primary bearing for the drive train. The wind turbine can be free of any additional bearings supporting the drive train to the nacelle and the turbine bed as a whole. The primary bearing can be independent of any other bearings. The rotor shaft can be supported on the nacelle solely via the primary bearing. Similarly, the gearbox can also be supported on the nacelle solely via the primary bearing. In this case, stationary components of the housing, such as a gearbox housing, are attached to the rotor bearing housing. However, the gearbox can also be additionally supported on the nacelle bed, for example, via a spring-damper system or by bolting the gearbox housing to the nacelle. A rotating part of the gearbox, such as an input shaft, can be supported on the rotor shaft via the two bearings.Optionally, the generator can also be mounted on the nacelle via the main bearing. Alternatively, the generator can be additionally supported on the machine bed, for example via a spring-damper system or by bolting the gearbox housing to the machine bed. The first bearing can be arranged axially in a rotor-side end region of the rotor bearing housing. The first bearing, for example, forms a rotor-side bearing. The second bearing can be arranged axially in a generator-side end region of the rotor bearing housing. The second bearing, for example, forms a generator-side bearing. The two bearings can be axially spaced apart from each other. The two bearings can be arranged coaxially. In the axial region where the two bearings are arranged, the housing can be thickened and, alternatively or additionally, stiffened. The housing can have a closed circumferential ring region in the axial region where the two bearings are arranged. The axial direction, a radial direction, and a circumferential direction can be defined by the axis of rotation of the rotor shaft and, alternatively or additionally, by the axis of rotation of the respective bearings. The gearbox can have an input shaft and an output shaft. The gearbox can have a gearbox housing. The generator can have a stator and a rotor. The generator can have a generator housing. The input shaft of the gearbox can be connected to the rotor shaft. The output shaft of the gearbox can be connected to the rotor of the generator. The generator housing can form the stator, or the stator can be mounted in the generator housing. The gearbox can have a planetary gear set. For example, a planet carrier can form the input shaft. For example, a sun gear can form the output shaft. For example, a ring gear can be mounted in the gearbox housing or form the gearbox housing. The fastening system includes a stationary component. This component is designed so that the rotor shaft can be fixed to the stationary component for the purpose of disassembling the first bearing. This can be achieved using fixing devices such as through holes or blind holes with internal threads in the stationary component and the rotor shaft, or a clamping device. The stationary component can be an immobile component that can still bear the loads supported by the first bearing and, optionally, the second bearing on the rotor bearing housing, even without the first bearing being installed. For example, the stationary component could be the machine bed, the rotor bearing housing, or another load-bearing component of the nacelle. The rotor shaft can also be temporarily secured to the machine bed or the rotor bearing housing using fasteners, such as screws. In this case, the rotor shaft is no longer rotatably mounted.The drive train is then, for example, no longer operational. The connection of the rotor shaft to the stationary component can be designed, for example, to withstand all loads that act or could act on the first bearing when the wind turbine is at rest. The fixing can be accessible when the drive train is assembled. For example, the rotor shaft can be bolted directly or via the hub to a flange of the rotor bearing housing. Disassembly of the first bearing can mean removing the first bearing from its bearing seat. Disassembly of the first bearing can mean removing at least part or all of the first bearing from the rotor bearing housing. This allows the first bearing to be replaced and / or serviced. The first bearing can be disassembled during disassembly or remain in an operational state. To remove the first bearing, the rotor shaft can first be secured. The first bearing can then be removed from the rotor bearing housing without having to dismantle the rotor itself. The rotor and other drivetrain components can then continue to be supported on the machine bed via the rotor bearing housing. Removing the first bearing may require dismantling the gearbox and, alternatively or additionally, the generator. However, the fastening system can also be designed so that the first bearing can be pushed through the gearbox and, alternatively or additionally, the generator for removal. In one embodiment of the fastening system, the stationary component can be formed by the rotor bearing housing. Fixing the rotor shaft to the rotor bearing housing can be very simple, since the rotor shaft is already positioned adjacent to the rotor bearing housing. Furthermore, the rotor bearing housing can be designed to absorb the loads acting on the first bearing, so that, compared to a design without the possibility of fixing the rotor shaft, no reinforcement is necessary for mounting the first bearing. The rotor shaft and the rotor bearing housing can have axially adjacent and radially extending flanges to which they can be attached for disassembly of the first bearing. In one embodiment of the fastening system, the rotor bearing housing may have an access opening. This access opening may be located at an end facing away from the wind turbine rotor. For example, the access opening may be located on an end face of the rotor bearing housing. The access opening may face the gearbox and, alternatively or additionally, the generator. The first bearing can be removed through the access opening during disassembly. For example, the first bearing can be pulled axially out of the rotor bearing housing through the access opening. The access opening can be an axial through-hole in the rotor bearing housing. The access opening can be closed by a cover. The cover can be removable for disassembly of the first bearing. The cover can form part of the rotor bearing housing or be separate. The cover can be bolted on. The cover can form a connecting part to which the generator and, alternatively or additionally, the gearbox with the rotor bearing housing are attached. The second bearing can be mounted in the cover. By removing the cover, or at least during the removal of the cover, the second bearing can be disassembled. The second bearing may, for example, only be disassemblable when the rotor shaft is fixed to the stationary component. It may be necessary to disassemble the second bearing before the first bearing can be removed from the access opening. When disassembling one of the bearings, it can at least be loosened from its seat.During disassembly, at least one outer ring of each bearing can be detached. When disassembling one of the bearings, it is also possible to disassemble the bearing by separating the outer ring from an inner ring. In one embodiment of the fastening system, as already described, the fastening system can be provided with a second bearing. The second bearing can be arranged next to the first bearing on a side facing away from the rotor, for example, axially spaced from the first bearing. The second bearing can be mounted on the rotor shaft. The second bearing can also be removed for disassembly through the access opening. Removal can be accomplished by releasing the access opening by removing the cover. In one embodiment of the fastening system, a radial clearance between the rotor shaft and the rotor bearing housing can widen axially towards the end furthest from the rotor. The space between an outer surface of the rotor shaft and an inner surface of the rotor bearing housing can increase axially away from the rotor and, alternatively or additionally, towards the access opening. This facilitates the removal of the first bearing. For example, the first bearing can be easily moved along the rotor shaft towards the access opening. The radial clearance between the rotor shaft and the rotor bearing housing can increase monotonically from the first bearing's seat to the access opening. For instance, the radial clearance between the rotor shaft and the rotor bearing housing does not decrease axially from the first bearing's seat towards the access opening in any axial region.The radial clearance between the rotor shaft and the rotor bearing housing can widen continuously, for example conically, or in stages. For example, the radial clearance between the rotor shaft and the rotor bearing housing can increase because the inner diameter of the rotor bearing housing widens axially towards the end of the housing furthest from the rotor. The inner diameter can increase due to this widening. It can widen towards the access opening from the first bearing seat. The inner diameter can increase monotonically from the first bearing seat to the access opening. For example, the inner diameter does not decrease axially from the first bearing seat to the access opening in any axial region. The inner diameter can widen continuously, for example conically, or in steps. However, the rotor bearing housing can also have a constant inner diameter between the first bearing seat and the access opening. Alternatively or additionally, the radial clearance between the rotor shaft and the rotor bearing housing can increase by the rotor shaft's outer diameter tapering axially towards the end of the bearing housing furthest from the rotor. The outer diameter can decrease due to this tapering. It can taper towards the access opening from the first bearing seat. The outer diameter can decrease monotonically from the first bearing seat to the access opening. For example, the outer diameter does not increase axially from the first bearing seat to the access opening in any axial region. The outer diameter can taper continuously, for example conically, or in steps. However, the rotor shaft can also have a constant outer diameter between the first bearing seat and the access opening. In one embodiment of the fastening system, the fastening system may include a slide. The slide can be fastened in the rotor bearing housing. For example, the slide may have a guide rail that can be attached to the rotor bearing housing, for instance, with a screw. The slide may only be fastened after the access opening has been opened and, alternatively or additionally, after the second bearing has been removed. The wind turbine cannot be operated with the slide fastened. The first bearing can be guided out of the rotor bearing housing during disassembly using the slide. The slide may have a carriage that is, for example, held on the guide rail so that it can be moved translationally in the axial direction. The first bearing can be fastened to the slide, for example, to its carriage.The slide can hold the first bearing when it is moved axially through the rotor bearing housing for disassembly. The slide can, for example, hold only the outer ring of the first bearing or the entire first bearing. The slide can also be used first to remove the outer ring of the first bearing from the rotor bearing housing and then to remove the rest of the first bearing. The slide can be driven. The drive for the slide can also be provided by the wind turbine. Preferably, the slide can be connected to a motor-driven device, for example, a crane installed in the nacelle of the wind turbine, to drive the slide. For example, the slide, or at least the mounting system for it, can have one or more deflection pulleys. This allows the first bearing to be moved in a controlled manner even if the rotor shaft's axis of rotation is tilted relative to the horizontal.The sliding mechanism allows even the extremely heavy first bearings of large wind turbines, which can weigh several tons, to be removed. Furthermore, the sliding mechanism facilitates dismantling when the interior of the rotor bearing housing is too confined, preventing, for example, a technician from accessing the first bearing. The second bearing, for instance, can be located directly at the end of the rotor bearing housing facing away from the rotor and thus be removed without the sliding mechanism. Alternatively, the second bearing can be guided by the sliding mechanism during dismantling, for example, to a storage location spaced away from the rotor bearing housing. In one embodiment of the fastening system, the fastening system may be designed to release an outer ring of the first bearing from its seat in the rotor bearing housing by means of a screw. The screw can exert an axial force on the outer ring to release it from its seat in the rotor bearing housing. This axial force can be exerted, for example, by turning the screw in a thread or by tightening a nut on the screw. The screw, however, may not be used, for example, to fix the outer ring to the rotor bearing housing. In the operational state of the wind turbine, the screw is not located in the rotor bearing housing. The fastening system may include a tool set for releasing the outer ring of the first bearing from its seat, which contains the screw.For example, a clamping element that axially secures the outer ring to the rotor bearing housing can be loosened for disassembly and replaced with a counter-bearing element. The screw is inserted through a through-hole in the counter-bearing element and screwed to the outer ring. Using another screw, such as a nut, the outer ring is then axially pulled out of its seat. Subsequently, a pulling element, such as a hook, can be inserted into the same counter-bearing element or into another counter-bearing element that is then inserted, and pull the inner ring and, alternatively or additionally, the rolling elements of the first bearing out of its seat on the rotor shaft. Alternatively, the outer ring can have a through-hole with an internal thread. The screw can be screwed into this hole and then its tip can be supported against a shoulder on the rotor bearing housing. This also allows the outer ring to be axially pressed out of its seat. Alternatively or additionally, the outer ring of the first bearing can only partially contact the rotor bearing housing. For example, a contact surface of the outer ring might only extend over a portion of its axial length. In this case, the outer ring of the first bearing can be removed from its seat in the rotor bearing housing with minimal effort. In one embodiment of the fastening system, the rotor bearing housing may have at least one through-opening in a circumferential wall through which the first bearing is accessible for disassembly. The through-opening may extend radially through the rotor bearing housing and may be located axially adjacent to the first bearing. This allows easy access to the first bearing for disassembly. For example, the screw for loosening the outer ring from its seat in the rotor bearing housing can be inserted through the through-opening. Furthermore, the fastening of the first bearing can be loosened from outside the rotor bearing housing through the through-opening. The through-opening may also allow the carriage to be fastened to the rotor bearing housing and, alternatively or additionally, to the first bearing.Several circumferential and, alternatively or additionally, axially spaced through-openings may be provided. Through-openings adjacent to the second bearing may also be provided for its removal. The through-openings may be closed by a cap during operation. Alternatively or additionally, the bearings may also be sealed. A second aspect concerns a wind turbine that features the mounting system described in the first aspect. The respective advantages and further characteristics can be found in the description of the first aspect, whereby embodiments of the first aspect also form embodiments of the second aspect and vice versa. The wind turbine includes the nacelle. The nacelle includes the machine bed. The wind turbine includes the rotor shaft, optionally with the rotor attached to it. The wind turbine may include the tower. The rotor bearing housing is attached to the machine bed. The rotor shaft is rotatably mounted in the rotor bearing housing with the first bearing. The rotor shaft can be fixed to a stationary component for the purpose of removing the first bearing. The gearbox may be attached to the machine bed via the rotor bearing housing. The generator may be attached to the machine bed via the rotor bearing housing.The rotor bearing housing and the machine bed can be designed as separate components. A third aspect concerns a method for disassembling a first bearing from a rotor bearing housing of a wind turbine. This method can be used to disassemble the first bearing on the wind turbine as described in the second aspect, and alternatively or additionally on the fastening system as described in the first aspect. The respective advantages and further features are described in the first and second aspects, whereby embodiments of the first and second aspects also constitute embodiments of the third aspect, and vice versa. In this process, the rotor bearing housing is attached to a machine bed in a nacelle of the wind turbine. The first bearing is fixed in the rotor bearing housing, at least initially. A rotor shaft of the wind turbine is rotatably mounted to the rotor bearing housing via the first bearing, at least initially. The process includes a step of fixing the rotor shaft to a stationary component. For this purpose, the rotor shaft is, for example, bolted to the rotor bearing housing as a stationary component. The process includes a step of loosening the fastening of the first bearing after the rotor shaft has been fixed. The first bearing can then be removed from the rotor bearing housing, for example, by axial displacement through the access opening. This loosening can involve detaching the first bearing from the rotor bearing housing and, alternatively or additionally, from the rotor shaft. Detaching the first bearing from the rotor bearing housing and from the rotor shaft can be done simultaneously or sequentially. For example, the outer ring is first detached from its seat in the rotor bearing housing. Only then is the inner ring detached from its seat on the rotor shaft.The method may include a step of loosening and, alternatively or additionally, moving the gearbox away from the rotor bearing housing. The method may include a step of loosening and, alternatively or additionally, moving the generator away from the gearbox and, alternatively or additionally, from the rotor bearing housing. The generator can be loosened and moved away together with the gearbox. The method may include a step of opening the access opening in the rotor bearing housing. The method may include a step of loosening and, alternatively or additionally, removing the second bearing, for example, from the rotor bearing housing. The method may include a step of mounting the carriage. The method may include a step of attaching the first bearing to the carriage of the carriage.The procedure may include a step of removing the first bearing from the rotor bearing housing, for example by means of the slide. Brief description of the characters Fig. 1 schematically illustrates a wind turbine with a drive train. Fig. 2 schematically illustrates, in a sectional view, a first embodiment of a drive train mounting system for the wind turbine of Fig. 1 in an operational state. Fig. 3 schematically illustrates, in a sectional view, the disassembly of bearings for a rotor shaft in the mounting system according to Fig. 2. Fig. 4 schematically illustrates, in a sectional view, a second embodiment of the drive train mounting system for the wind turbine of Fig. 1 in an operational state. Fig. 5 schematically illustrates, in a sectional view, the disassembly of bearings for a rotor shaft in the mounting system according to Fig. 4. Fig. 6 schematically illustrates, in a sectional view, a third embodiment of the drive train mounting system for the wind turbine of Fig. 1.Fig. 1 in an operational state of the wind turbine. Fig. 7 schematically illustrates in a sectional view a fourth embodiment of the drive train mounting system for the wind turbine of Fig. 1 in an operational state of the wind turbine. Fig. 8 schematically illustrates in a sectional view a first design of a rotor bearing housing for the various embodiments of the mounting system. Fig. 9 schematically illustrates in a sectional view a second design of the rotor bearing housing for the various embodiments of the mounting system. Fig. 10 schematically illustrates a first variant for releasing an outer ring of a bearing from its seat in the rotor bearing housing by means of a screw for the various embodiments of the mounting system.Figure 11 schematically illustrates a second variant for loosening the outer ring of the bearing from its seat in the rotor bearing housing using the screw in the various embodiments of the fastening system. Figure 12 schematically illustrates another design of the seat of the outer ring of the bearing in the rotor bearing housing in the various embodiments of the fastening system. Figure 13 schematically illustrates in a side view a first design of the rotor bearing housing in the various embodiments of the fastening system, which has at least one through-opening in a circumferential wall. Figure 14 schematically illustrates in a side view a second design of the through-openings in the circumferential wall of the rotor bearing housing in the various embodiments of the fastening system.Figure 15 schematically illustrates, in a top view, a third design of the through-openings in the circumferential wall of the rotor bearing housing for the various embodiments of the fastening system. Figure 16 schematically illustrates, in a side view, a slide of the fastening system, which is mounted in the rotor bearing housing when the wind turbine is not operational, for the purpose of removing the first bearing and by means of which the first bearing can be guided out of the rotor bearing housing during disassembly. Figure 17 schematically illustrates, in a sectional view, the slide of the fastening system. Figure 18 schematically illustrates, in a side view, the slide of the fastening system, with the bearing now moved by means of the slide towards an access opening in the rotor bearing housing. Detailed description of embodiments Fig. 1 illustrates a wind turbine 10 with a horizontal drive train. The wind turbine 10 has a rotor 12, which is held on a rotor shaft 16 via a hub 14. The axis of rotation of the rotor shaft 16 extends essentially horizontally. The rotor shaft 16 is supported in a nacelle 20 by two rolling bearings 18. A rotor bearing housing 40 is provided for this purpose, which is attached to a machine bed 42 of the nacelle 20. The rotor shaft 16 is mechanically connected to a generator 24 via a gearbox 22. A brake 26 is also arranged in the operative connection between the gearbox 22 and the generator 24, which acts on an input shaft of the generator 24. The nacelle 20 is rotatably mounted at the upper end of a tower 28, which is anchored to the ground. In another embodiment, the wind turbine 10 is designed as an offshore installation. In addition to tower 28, wind turbine 10 has a grid connection 30.The first bearing 18 faces the rotor 12 and is also referred to as the rotor-side bearing 18. The second bearing 18 faces the generator 24 and is also referred to as the generator-side bearing 18. Both bearings 18 are designed as tapered roller bearings. At least the rotor bearing housing 40, the rotor shaft 16, the rotor 12, the gearbox 22, and the generator 24 form components of the drive train of the wind turbine 10. In the illustration of Fig. 1, the gearbox 22 is arranged axially between the rotor bearing housing 40 and the generator 24. Both the generator 24 and the gearbox 22 are attached to the machine bed 42 exclusively via the rotor bearing housing 40. The generator 24 is indirectly connected to the rotor bearing housing 40 via the gearbox 22 and is thus attached to the machine bed 42 via both the gearbox 22 and the rotor bearing housing 40. The rotor 12 is also supported on the machine bed 42 exclusively via the rotor shaft 16 and the main bearing. Therefore, it is usually necessary to disassemble the rotor 12 if the two bearings 18 are to be replaced or serviced. Fig. 2 illustrates in a sectional view a first embodiment of a fastening system for attaching the drive train of the wind turbine 10 from Fig. 1 to the nacelle 20 of the wind turbine 10. The fastening system comprises the rotor bearing housing 40 and the two bearings 18, 38. The first bearing 18 is located in the rotor bearing housing 40. The second bearing 38 is located in a cover 50 and is thus indirectly fastened in the rotor bearing housing 40. The cover 50 closes an access opening at an end of the rotor bearing housing 40 facing away from the rotor 12. The cover 50 is screwed to the end face of the rotor bearing housing. By loosening the cover 50, the second bearing 38 is released from the rotor bearing housing 40 and, upon removal of the cover 50, is also automatically removed from an interior space within the rotor bearing housing 40. The gearbox 22 with its housing is screwed to the cover 50.The generator 24 is attached to the housing of the gearbox 22 and thus indirectly connected to the cover 50 and therefore to the rotor bearing housing 40. An input shaft 52 of the gearbox 22 is bolted to the rotor shaft 16, so that during operation a drive force can be introduced from the rotor 12 into the gearbox 22. Fig. 2 shows the mounting system and thus also the wind turbine 10 in an operational state. Fig. 3 illustrates, in a sectional view, the disassembly of the two bearings 18, 38 in the first embodiment of the fastening system. Disassembly of the rotor 12 is not required. Instead, the fastening system is designed to fix the rotor shaft 16 to a stationary component of the fastening system for the disassembly of the first bearing 18 and also the second bearing 38. In this case, the rotor bearing housing 40 forms the stationary component. As can be seen in Fig. 3, to disassemble the two bearings 18, 38, the rotor shaft 16 is first bolted to the rotor bearing housing 40 at a rotor-side end region using two adjacent and radially projecting flanges of the rotor bearing housing 40 and the rotor shaft 16. This temporarily fixes the rotor shaft 16, and the wind turbine 10 is no longer operational.Nevertheless, the respective loads, which were previously introduced into the rotor bearing housing 40 via the two bearings 18, 38, can now be transferred via this screw connection. The rotor bearing housing 40 then continues to transfer these forces into the machine bed 42. To dismantle the two bearings 18 and 38, the gearbox 22 and the generator 24 are first detached from the rest of the drive train. This is done by loosening the bolts connecting the gearbox 22 housing to the cover 50 and the bolts connecting the input shaft 52 to the rotor shaft 16. In the example shown, the input shaft 52 is designed as a planet carrier for a planetary gear set of the gearbox 22. The bolts connecting the input shaft 52 to the rotor shaft 16 are accessible from the outside. The gearbox 22 and the generator 24 are then moved away from the rotor bearing housing 40, for example, using a crane integrated into the nacelle 20 of the wind turbine 10 or using rails temporarily installed in the nacelle 20. Finally, a locking element 54 is released, which axially secures the second bearing 38 in position during operation. The fixing element 54 is designed here as a clamping ring, which is screwed to the rotor shaft 16 in the operational state.Then the cover 50, with the second bearing 38 contained therein, is detached from the rotor bearing housing 40 and moved axially away to expose the access opening at the end of the rotor bearing housing 40 facing away from the rotor 12 and thus on the gearbox side. This access opening is designed as an axial through-hole. Alternatively, the second bearing 38 can first be removed alone, followed by the cover 50. The respective parts are then moved away again using the crane integrated into the nacelle 20. After the access opening has been released, a further locking element 56 is loosened, which axially secures the first bearing 18 in position during operation. This additional locking element 56 is designed as a clamping ring, which is screwed to the rotor bearing housing 40 in the operational state. The first bearing 18 can then be moved axially along the rotor shaft 16 towards the access opening and subsequently removed from the interior of the rotor bearing housing 40 through the access opening. This allows for replacement and maintenance of the first bearing 18 without having to disassemble the rotor 12. In the example shown, assembly is carried out in reverse order. To facilitate the movement of the first bearing 18 from its seat to the access opening, a radial clearance between the rotor shaft 16 and the rotor bearing housing 40 widens axially towards the end furthest from the rotor 12, and thus towards the access opening. The distance between an outer circumference of the rotor shaft 16 and an inner circumference of the rotor bearing housing 40 therefore increases from the seat of the first bearing 18 towards the access opening, which is also illustrated by the two arrows 58 and 60, shown exclusively in Fig. 2 for clarity. Arrow 60, which is closer to the access opening than arrow 58, is therefore longer than arrow 58. In the illustrated embodiment, the outer diameter of the rotor shaft 16 decreases continuously from the seat of the first bearing 18 towards the access opening. In the axial direction towards the access opening, the outer wall of the rotor shaft 16 is inclined radially inwards at a constant angle, thus causing the rotor shaft 16 to taper conically. Furthermore, the inner diameter of the rotor bearing housing 40 increases continuously from the seat of the first bearing 18 towards the access opening, thus causing the rotor bearing housing to widen conically. In the axial direction towards the access opening, the inner wall of the rotor bearing housing 40 is inclined radially outwards at a constant angle. In the figures and embodiments shown here, the widening of the radial clearance between the rotor shaft 16 and the rotor bearing housing 40 in the axial direction towards the access opening is exaggerated for illustrative purposes.In actual implementation, the increase can be a few millimeters or centimeters. The inclination of the inner wall of the rotor bearing housing 40 and the outer wall of the rotor shaft 16 is then correspondingly much smaller than shown here. Figure 4 shows a second embodiment of the fastening system, which is similar to the first embodiment. Only the differences are explained. The cover 50 is omitted here. Instead, the gearbox housing 22 is screwed directly to the rotor bearing housing 40, thus closing the access opening. Furthermore, the second bearing 38 is not located in the rotor bearing housing 40 on the cover 50, which is not present here. Instead, the second bearing 38 is attached to a non-rotating component 62 of the gearbox 22 by means of the fixing element 54. The non-rotating component 62 is designed as a bearing seat for the second bearing 38 and is fixed to the gearbox housing 22. In other embodiments, the non-rotating component 62 is formed by the housing itself. The input shaft 52 is rotatably mounted in the second bearing 38. The rotor shaft 16 is thus indirectly rotatably mounted on the second bearing 38 via the input shaft 52. When disassembling the first bearing 18, the access opening in the rotor bearing housing 40 is now directly exposed by loosening the gearbox 22 and moving it away, as shown in Fig. 5. The second bearing 38 can remain attached in the gearbox 22, and the fixing element 54 does not need to be loosened. The input shaft 52 remains supported, thus keeping the gearbox 22 in an operational state. This allows testing of the gearbox 22 and also the generator 24 in the detached state. Furthermore, securing the input shaft 52 for transport is not required, and the gearbox 22 can remain sealed. In the second embodiment, disassembling the first bearing 18 also requires loosening fewer screws and handling fewer parts. In contrast, in the first embodiment, the individual parts to be handled during disassembly of the first bearing 18 can be lighter.In addition, the two bearings 18, 38 can be aligned coaxially more easily and precisely. Figure 6 shows a third embodiment of the fastening system in the operational state of the wind turbine 10, which is a modification of the first embodiment. Only the differences are described. The drive train now has an elastic connecting element 70 by means of which the rotor shaft 16 is connected to the input shaft 52 of the gearbox 22. The input shaft 52 is therefore no longer directly and rigidly bolted to the rotor shaft 16. A housing element 72 is arranged radially outside the connecting element 70, in which the connecting element 70 is received. The housing element 72 closes the access opening of the rotor bearing housing 40, just like the cover 50 in the first embodiment. The second bearing 38 is attached to the housing element 72, similar to the cover 50 in the first embodiment.The housing of the gearbox 22 is connected to the rotor bearing housing 40 in a rotationally fixed manner via the housing element 70 by means of appropriate screw connections. Figure 6 also shows the planetary gear set 74 of the transmission 22. The input shaft 52 is formed by the planet carrier 80, which is rotatably mounted on the transmission housing 22 by two roller bearings 76. Due to the elastic connecting element 70, the mounting is not overconstrained. The planetary gear set 74 also includes a sun gear 82 and a ring gear 84. The ring gear 84 is attached to the transmission housing. The sun gear 82 forms the output shaft of the transmission 22, which is attached to a rotor of the generator 24. Several planet gears 86 are rotatably mounted on the planet carrier 80. The planet gears 86 mesh with the ring gear 84 and the sun gear 82, respectively. In other embodiments, the transmission 22 includes further planetary gear sets. In the embodiment shown in Fig. 6, the outer diameter of the rotor shaft 16 does not taper from the seat of the first bearing 18 to the access opening. Instead, the rotor shaft 16 has a constant outer diameter. However, the radial clearance between the rotor shaft 16 and the rotor shaft housing 40 widens towards the access opening due to the widening of the inner diameter of the rotor shaft housing 40. In the third embodiment of the fastening arrangement, the first bearing 18 is disassembled analogously to the first embodiment, as illustrated in Fig. 3. Here, the housing element 72 is loosened instead of the cover 50 to expose the access opening in the rotor bearing housing 40. To detach the gearbox 22, the connecting element 70 is loosened, which can remain on the input shaft 52 of the gearbox 22. Figure 7 shows a fourth embodiment of the fastening system in the operational state of the wind turbine 10, which is a modification of the first embodiment. The internal structure of the gearbox 22 is also shown, which is designed as in the third embodiment of Figure 6. The rotor shaft 16 is also designed as in the third embodiment and thus has a constant outer diameter. Only further differences are explained. In the fourth embodiment, the gearbox 22 is not attached to the machine bed via the rotor bearing housing 40. Instead, the gearbox housing 22 is attached directly to the machine bed 42 via rubber bushing elements 90. Due to the elastic support of the gearbox 22 by the bushing elements 90 on the machine bed 42, the bearing arrangement is also not overconstrained here, even though the input shaft 52 of the gearbox 22 is rigidly attached directly to the rotor shaft 16 by a screw connection. Figure 8 shows a first embodiment of the rotor bearing housing 40, in which the radial clearance between the rotor shaft 16 and the rotor bearing housing 40 widens in the axial direction towards the access opening because the inner diameter of the rotor bearing housing increases radially outwards in this direction due to an inclination of the wall. This corresponds to the design shown in the embodiments described above. Figure 9 shows a second embodiment of the rotor bearing housing 40, in which the radial clearance between the rotor shaft 16 and the rotor bearing housing 40 widens in the axial direction towards the access opening because the inner diameter of the rotor bearing housing 40 increases once in the direction of the access opening by means of a step 100 axially adjacent to the seat of the first bearing 18. In other embodiments, several such steps 100 are provided.Both variants of the design of the rotor bearing housing 40 for increasing the radial clearance between the rotor shaft 16 and the rotor bearing housing 40 in the axial direction towards the access opening are combined in further embodiments with any of the illustrated embodiments of the fastening system or, more generally, with a rotor shaft 16 having a constant outer diameter or an outer diameter that decreases axially towards the access opening. In other embodiments, the rotor shaft 16 has a design in which the outer diameter decreases inwards by one or more steps instead of by a radial inclination of an outer circumferential surface. Fig. 10 schematically illustrates a first variant for loosening an outer ring 110 of the first bearing 18 and, alternatively or additionally, of the second bearing 38 by means of a screw 112 from its seat in the rotor bearing housing 40 or another component in the various embodiments of the fastening system. The outer ring 110 is axially fixed by a fixing element, such as the fixing element 56. This is shown in Fig. 10 in partial image A. This fixing element 56 is screwed to the component that forms the seat and is removed to loosen the outer ring 110. This is shown in Fig. 10 in partial image B. Subsequently, a counter-bearing element 114 is arranged approximately at its position and fastened to the component that forms the seat by a screw connection. This is shown in Fig. 10 in partial image C. The counter-bearing element 114 has a through-hole which is aligned coaxially with a blind hole 116.The screw 112 is guided through the through-hole in the abutment element 114 and screwed to the outer ring 110 via the blind hole 116. By turning a nut 118 on the screw 112, the screw 112 is retracted axially through the through-hole in the abutment element 114. This also pulls the outer ring 110 axially towards the access opening. In one embodiment, the outer ring 110 detaches from the rest of the bearing. This is shown in Fig. 10, sub-image C. In another embodiment, the entire bearing is pulled axially towards the access opening. In sub-image D of Fig. 10, a pulling device 120 is shown, which is attached to the component forming the seat by a screw connection with a further abutment element 122. The pulling device 120 has an actuator 124 and a hook element 126, which engages one or more rolling elements 130 of the bearing and can thus pull the rolling elements 130 and an inner ring 132 of the bearing axially towards the access opening. This also releases the inner ring 132 from its seat. This is also illustrated in sub-image D. Fig. 11 schematically shows a second variant for removing the outer ring 110 of the first bearing 18 and, alternatively or additionally, of the second bearing 38 from its seat in the rotor bearing housing 40 or another component in the various embodiments of the fastening system using the screw 112. The outer ring 110 has a different design and extends partially radially along an end face of the component that forms the seat for the outer ring 110. This part of the outer ring 110 has a through-hole 140 with an internal thread. Furthermore, this part of the outer ring 110 is screwed to the end face of the component that forms the seat for the outer ring 110. To remove the outer ring 110 from its seat, this screw connection is first loosened. Then, the screw 112 is screwed into the through-hole 140.The screw 112 is supported against the end face of the component that forms the seat for the outer ring 110 and thus presses the outer ring 110 axially towards the access opening. This is shown in partial image B of Fig. 11. In partial image A of Fig. 11, the outer ring 110 is shown attached to its seat. Figure 12 shows another design of the seat of the outer ring 110 of the bearing in a component, such as the rotor bearing housing 40, for the various embodiments of the fastening system. For axial fixation, the outer ring 110 is also screwed to an end face of the component that forms the seat for the outer ring 110. This is illustrated in partial image A of Figure 12. The outer ring 110 has only a small axial extent of a region 150 of its outer wall, which rests radially on the outside of the seat in the component. To loosen the outer ring 110, the screw connection is loosened. Due to the small axial extent of the region 150 of the outer wall, which rests radially on the outside of the seat in the component, the outer ring 110 can then be loosened with minimal force. This is illustrated in partial image B of Figure 12. Fig. 13 schematically illustrates in a side view a first embodiment of the rotor bearing housing 40, which has at least one through-opening 160 in a circumferential wall. This allows access to the interior of the rotor bearing housing 40 even when the wind turbine 10 is in operational condition. The radially extending through-opening 160 allows, for example, the first bearing 18 to be removed, as previously described. It also allows the mounting of a slide 200, which will be described below. In the example shown in Fig. 13, the through-opening 160 is oval and located at a rotor-side end region. The example shown has two coaxial through-openings 160 on opposite sides, which point essentially in a horizontal direction. Due to its oval shape and the small size and number of through-openings, the rotor bearing housing 40 can withstand high loads.In yet another embodiment, the rotor bearing housing 40 has such through-openings 140 on the underside and alternatively or additionally on the upper side. Fig. 14 schematically illustrates in a side view a second embodiment of the rotor bearing housing 40, which has at least one through-opening 160 in a circumferential wall. In this embodiment, two through-openings 160 are visible side by side in the vertical direction, one in the rotor-side end region and the other in the generator-side end region. The generator-side end region is located in the area of ​​the access opening. The second embodiment also allows easy access to the second bearing 38 from the interior of the rotor bearing housing 40. The example shown has coaxial through-openings 160 on an opposite side to the through-openings 160 shown, which point essentially in a horizontal direction. In yet another embodiment, the rotor bearing housing 40 also has such through-openings 140 on the underside and, alternatively or additionally, on the upper side. Fig. 15 schematically illustrates in a top view a third embodiment of the rotor bearing housing 40, which has at least one through-opening 160 in a circumferential wall. In this embodiment, two through-openings 160 are provided side by side in the transverse direction. In this third embodiment, these through-openings 160 extend from the rotor-side end region to the generator-side end region. This third embodiment allows for easy handling of the first bearing 18 from the outside through the circumferential wall of the rotor bearing housing 40 when the first bearing 18 is moved to the access opening for removal from the rotor bearing housing 40 during disassembly. In further embodiments, the different configurations of the through-openings 160 are combined. For example, the through-openings 160 of the third configuration according to Fig. 15 are provided on the top side, and the through-openings 160 of the second configuration according to Fig. 14 are provided on the sides. Such a configuration is shown in Figs. 16, 17 to 18. Figures 16, 17 to 18 illustrate the slide 200, which is mounted in the rotor bearing housing 40. In one embodiment, the slide 200 is mounted after the access opening of the rotor bearing housing 40 has been opened. The slide 200 allows the first bearing to be guided out of the rotor bearing housing 40 during disassembly. The slide has a guide rail 202, which is screwed to an end face of the rotor bearing housing 40 on the outside in the area of ​​the access opening. In one embodiment, screw holes can be used to attach other components, such as the cover 50, when the system is operational. Furthermore, the guide rail is screwed to the rotor bearing housing 40 at one end section axially adjacent to the seat of the first bearing 18. This screw connection extends radially through the wall of the rotor bearing housing 40. A carriage 204 is axially displaceable on the guide rail 202, here by means of rollers.The first bearing 18 is attached to the carriage 204 for its disassembly. The slide 200 can guide the first bearing 18 out of the rotor bearing housing 40 during disassembly. The fastening by means of a screw connection is shown in Fig. 17. Figure 18 shows how the first bearing 18, guided by the carriage 204, was moved towards the access opening. The axis of rotation of the rotor shaft 16, and thus also the orientation of the guide rail 202, is inclined to a horizontal plane. Accordingly, gravity pulls the first bearing 18 towards the access opening. This movement is controlled by a brake and, alternatively or additionally, by an actuator. In this case, the carriage 204 is connected to the crane of the wind turbine 10 (not shown), which is integrated into the nacelle 20, so that no additional drives are required. Reference sign 10 Wind turbine 12 Rotor 14 Hub 16 Rotor shaft 18 First rolling bearing 20 Nacelle 22 Gearbox 24 Generator 26 Brake 28 Tower 30 Grid connection 38 Second rolling bearing 40 Rotor bearing housing 42 Machine bed 50 Cover 52 Input shaft 54 ​​Fixing element 56 Further fixing element 58 Arrow 60 Arrow 62 Non-rotating component 70 Elastic connecting element 72 Housing element 74 Planetary gear set 76 Rolling bearing 80 Planet carrier 82 Sun gear 84 Ring gear 86 Planet gears 90 Bushing element 100 Stage 110 Outer ring 112 Screw 114 Abutment element 116 Blind hole 118 Nut 120 Pulling device 122 Further abutment element 124 Actuator 126 Hook element 130 Rolling element 132 Inner ring 140 Through opening 150 Area 160 Through opening 200 Slide 202 Guide rail 204 Carriage

Claims

Fastening system for a drive train of a wind turbine (10) on a nacelle (20) of the wind turbine (10), wherein the fastening system comprises a rotor bearing housing (40), a stationary component and a first bearing (18), wherein the first bearing (18) is mounted in the rotor bearing housing (40) for rotatably supporting a rotor shaft (16) of the drive train, wherein the rotor bearing housing (40) is designed for attachment to a machine bed (42) of the nacelle (20), and wherein the fastening system is designed such that the rotor shaft (16) can be fixed to the stationary component for the purpose of disassembling the first bearing (18). Fastening system according to claim 1, characterized in that the stationary component is formed by the rotor bearing housing (40). Fastening system according to claim 1 or 2, characterized in that the rotor bearing housing (40) has an access opening at an end facing away from a rotor (12) of the wind turbine (10), through which the first bearing can be removed during disassembly. Fastening system according to claim 3, characterized in that the fastening system has a second bearing (38) which can also be removed through the access opening for disassembly. Fastening system according to one of the preceding claims, characterized in that a radial clearance between the rotor shaft (16) and the rotor bearing housing (40) widens in an axial direction towards the end facing away from the rotor (12). Fastening system according to one of the preceding claims, characterized in that the fastening system has a slide (200) which can be fastened in the rotor bearing housing (40) and by means of which the first bearing (18) can be guided out of the rotor bearing housing (40) during disassembly. Fastening system according to one of the preceding claims, characterized in that the fastening system is designed to release an outer ring (110) of the first bearing (18) from its seat in the rotor bearing housing (40) by means of a screw. Fastening system according to one of the preceding claims, characterized in that the rotor bearing housing (40) has at least one through-opening (160) in a circumferential wall through which the first bearing (18) is accessible for disassembly. Wind turbine (10) with a nacelle (20) which has a machine bed (42), with a rotor shaft (16) and with a fastening system according to one of the preceding claims, wherein the rotor bearing housing (40) is attached to the machine bed (42), the rotor shaft (16) is rotatably mounted in the rotor bearing housing (40) with the first bearing (18) and wherein the rotor shaft (16) can be fixed to a stationary component for the disassembly of the first bearing (18). Method for disassembling a first bearing (18) from a rotor bearing housing (40) of a wind turbine (10), wherein the rotor bearing housing (40) is attached to a machine bed (42) in a nacelle (20) of the wind turbine (10), wherein the first bearing (18) is fixed in the rotor bearing housing (40), and wherein a rotor shaft (16) of the wind turbine (10) with the first bearing (18) is rotatably mounted on the rotor bearing housing (40), wherein the method comprises at least the following steps: - fixing the rotor shaft (16) to a stationary component; - loosening the fastening of the first bearing (18) after fixing the rotor shaft (16).

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