ROTOR BEARINGS FOR A WIND TURBINE AND WIND TURBINE

Description

State of the art

[0001] The invention relates to a rotor bearing for a wind turbine according to the preamble of claim 1 and to a wind turbine according to the preamble of claim 16.

[0002] Rotor bearings in wind turbines are designed to transfer the forces and moments of the rotating rotor hub to the tower and foundation of the wind turbine, while simultaneously enabling torque transmission to the drive train and generator. The rotor bearing can be designed as a single moment bearing or as several distributed bearings, for example, as adjusted tapered roller bearings or fixed-loose bearings.

[0003] Due to the high forces and torques to be transmitted by the rotor hub, it is advantageous for the aforementioned bearing arrangements if the outer ring is connected to the rotating rotor hub and the stationary inner ring is connected to the nacelle. Such bearing arrangements are generally designed as grease-lubricated rotor bearings, as the grease provides a supporting sealing effect. To date, satisfactory sealing has not been achieved with oil lubrication, especially for externally rotating rotor bearings. The advantages of oil lubrication include, on the one hand, that the oil can be filtered during circulating lubrication, thus reducing the risk of particles in the lubricant rolling over, and, on the other hand, the possibility of actively controlling the oil temperature, allowing the bearing temperature to be better adjusted and, if necessary, eliminating the need for other, additional cooling / heating systems.

[0004] For example, DE 10 2017 107 553 A1 discloses a tapered roller bearing for supporting the rotor of a wind turbine, comprising an inner ring, an outer ring, and two rows of tapered rollers arranged in an O-arrangement between the inner ring and the outer ring. The gap between the inner ring and the outer ring is sealed at least on one side of the tapered roller bearing by a sealing arrangement comprising a main seal connected in a rotationally fixed manner to the inner ring and a seal race connected in a rotationally fixed manner to the outer ring. The seal race forms a sealing surface for the main seal.

[0005] From WO 2012 / 136632 A1, an oil-lubricated rolling bearing for supporting the rotor of a wind turbine is known, comprising a shaft seal which separates a bearing interior receiving rolling elements from a bearing exterior, and comprising a clamping arrangement for axially fixing the shaft seal, which clamping arrangement has an outflow for oil.

[0006] A disadvantage of the two aforementioned rolling bearings is that when oil is used as a lubricant, the resulting oil leakage can only be collected and drained away when the outer ring is stationary. When used as external rotor bearings, the known bearings cannot be reliably prevented from leaking oil into the machine housing.

[0007] JP 2009 036241 A describes a sealing arrangement for a wheel bearing whose watertightness is improved without increasing its rotational resistance or the press-fitting position accuracy. Disclosure of the invention

[0008] The object of the invention is therefore to provide a rotor bearing for a wind turbine and a wind turbine with a rotor bearing with improved sealing of an oil-lubricated bearing interior when used as an external rotor.

[0009] This object is achieved by a rotor bearing for a wind turbine having the features of claim 1 and a wind turbine having the features of claim 16.

[0010] This creates a rotor bearing for a wind turbine with an inner ring and an outer ring rotatable relative to the inner ring, in which the inner ring and outer ring define a bearing interior in which at least one row of rolling elements that can roll between the bearing rings is arranged. The rotor bearing further has sealing arrangements for sealing the bearing interior on one side in each case, wherein at least one of the sealing arrangements has a first seal connected in a rotationally fixed manner to the inner ring and a seal race connected in a rotationally fixed manner to the outer ring. A first seal race surface for the first seal is formed on the seal race.According to the invention, a ring attachment is fastened to the inner ring, which ring engages around the seal race in the radial direction, and a second seal is provided which acts between the seal race and the ring attachment and delimits an annular space formed between a radial outer surface of the seal race and a radial inner surface of the ring attachment.

[0011] The rotor bearing according to the invention is thereby equipped with at least a two-stage sealing system formed by the first and the second seal. The annular space enclosed between the first and the second seal forms an oil collection space for leakage oil escaping via the first seal. The radial inner surface of the ring attachment, which is fixedly mounted on the inner ring and encompasses the seal race, forms a fixed, radially outer wall of the annular space. With a substantially horizontal arrangement of the bearing axis, leakage oil is captured around the entire circumference by the ring attachment and collected in a lower circumferential region. The second seal reliably prevents the collected leakage oil from escaping.

[0012] The sealing arrangement according to the invention completely captures the escaping oil, which is subject to centrifugal forces and, when stationary, to gravity, and enables it to be returned to the bearing or otherwise returned to the oil circuit via the non-rotating ring attachment.

[0013] To form an oil sump, the first seal running surface preferably has a smaller diameter than the largest diameter of a roller contact surface for the row of rolling elements on the outer ring. For this purpose, the first seal running surface is preferably formed on a radially inwardly projecting section of the seal race. Due to the radial arrangement of the first seal running surface in the area of the roller contact surface, lubricating oil accumulates in the bearing interior up to the roller contact surface before the first seal is loaded with an oil column. This creates an oil sump in a lower circumferential area of the bearing interior, which provides the bearing with important emergency running properties. The oil sump ensures sufficient lubrication of the bearing during rotation for emergency operation, even if the circulating lubrication fails. This increases operational reliability and failure safety, which is a major advantage, especially for wind turbines that are complex to maintain.

[0014] According to the invention, an outlet for connecting an oil return line is provided in the ring attachment, said outlet having a flow area that is at least partially arranged further outward in the radial direction than a sealing gap of the second seal. In this embodiment, the leakage oil collected in the annular space can be continuously drained, treated, and returned to the bearing interior via a circulating lubrication system. The advantage here is that the resulting leakage does not require any maintenance, since the oil level in the bearing interior can be kept largely constant by the oil return line. It can even be provided that the first seal is adjusted in such a way that a minimum leakage flow is maintained, for example, to lubricate the sealing gap of the first seal or to increase the oil circulation speed of the circulating lubrication system.

[0015] Alternatively or additionally, an oil collection container can be formed on the lower peripheral area of the attachment ring to collect any leaking oil. This oil collection container can be emptied during regular maintenance work, and the bearing can be relubricated with an appropriate amount of oil.

[0016] Preferably, a drip edge is formed on the radial outer surface of the seal race in the annular space upstream of the second seal to break off entrained oil. The drip edge prevents leaking oil from flowing or creeping along the radial outer surface of the seal race in the direction of the sealing gap of the second seal. Under the influence of gravity and / or centrifugal forces, the drip edge causes droplets of entrained oil to form and subsequently break off. The second seal is thus relieved of load and the tightness of the sealing arrangement is further increased. The drip edge is preferably designed to taper at an acute angle in the radial direction.

[0017] In a preferred embodiment, the first seal is axially clamped against the inner ring by means of the ring attachment. This allows the first seal to be easily replaced by loosening the ring attachment. For precise radial positioning, the first seal is preferably inserted into a radial shoulder or groove of the inner ring.

[0018] Preferably, the first seal is a radially acting seal with a sealing lip that bears against a radial inner surface of the seal race.

[0019] In particular, it can be provided that the first and second seals are held in position by the ring attachment and a second sealing running surface for the second seal is formed on the seal race. With such a sealing arrangement, both seals of the sealing system can be easily replaced by detaching the attachment ring from the inner ring. It is also advantageous that the sealing systems do not rotate and thus the sealing lips are not exposed to circumferential cyclic deformations. This arrangement is also particularly preferred when the seal race is formed integrally with the outer ring or is connected to it in such a way that it can only be separated from the outer ring when the bearing is removed.

[0020] Preferably, the first seal bears against the first seal running surface with a first lip preload that is greater than a second lip preload of the second seal. In this case, the first seal forms a primary seal, which serves the purpose of allowing the smallest possible leakage. The second seal acts as a secondary seal, which only needs to seal against splash oil and provides protection against dust penetrating from the outside. The lip preloads can be applied via the elasticity of the respective sealing material. To increase the lip preload, preloaded spring elements can be arranged in the first and / or second seal.

[0021] Axially acting engagement means can be provided on the ring attachment and / or the seal race for centering purposes, which engage with complementary engagement means on the inner and / or correspondingly on the outer ring. Since the first and second seals act between the ring attachment and the seal race and can only reliably seal different sealing gap widths with a limited tolerance of a few millimeters, precise positioning of the ring attachment and seal race relative to one another is desirable. Particularly with radially acting seals, precise centering of the ring attachment and seal race on the bearing axis is important to achieve an adequate sealing effect. For this purpose, it is advantageous to provide complementary engagement means on the ring attachment and inner ring or on the seal race and outer ring, which center the ring attachment and seal race during assembly.The engagement means may, for example, consist of a circumferential or segmented groove or a shoulder into which corresponding complementary axial projections of the other part engage.

[0022] The seal race can be attached to the outer ring by means of a screw connection and sealed against the outer ring with an O-ring located radially inside the screw connection. This ensures a secure seal of the bearing interior in the area of the joint surface between the seal race and the outer ring. The radially inside seal also protects the screw connection against oil seeping into the joint gap.

[0023] To further improve the seal, at least one additional sealing element can be provided between the first and second seals to relieve the second seal's load, dividing the annular space. In the simplest case, the additional sealing element can be designed, for example, as a stuffing box, which can be made of rubber or a felt material, for example. Alternatively or additionally, an additional lip seal can also be provided.

[0024] Furthermore, a further outlet can preferably be provided in the annular attachment between the further sealing element and the second seal. The annular space is divided by the further sealing element into two chambers, each provided with an outlet. One or both outlets can be connected to a check valve to prevent backflow of oil into the respective chamber.

[0025] In a preferred embodiment, the second seal and the further sealing element are designed as axially acting lip seals with a lip preload that is axially equal or opposite. By applying positive or negative pressure to the chamber formed between the further sealing element and the second seal, the sealing behavior of the chamber can be influenced. For example, with lip seals that act in axially opposite directions, the sealing effect of both seals can be increased by applying positive pressure to the chamber. With lip seals that are axially aligned in the same direction, positive pressure in the chamber formed between them can be used to relieve the load on the further sealing element and to push back the leaking oil flow in the sealing gap of the further sealing element.

[0026] In a preferred embodiment, the outer ring can have fastening holes for attaching the rotor bearing to the rotor of a wind turbine using fastening screws, and the seal race can extend radially into the area of the fastening holes to clamp the seal race during assembly of the rotor. Advantageously, no additional holes are required to attach the seal race to the outer ring, which would weaken the outer ring, since the forces acting on the seal race during operation are diverted via the clamp connection. To simplify assembly, at most a few holes in the outer ring are advantageous in order to be able to position the seal race relative to the outer ring and fix it in position at the factory.

[0027] The seal race is preferably made of steel and hardened at least in the area of the first seal running surface. This reduces wear on the seal race. The seal race can, in particular, be formed integrally with the outer ring. However, to reduce material consumption during production, a two-part design is preferred. A cost-effective design of the seal race from a plastic material is also conceivable.

[0028] In a preferred embodiment, the ring attachment is made of a plastic material. Since the ring attachment is only exposed to comparatively low forces, a plastic material meets the requirements. For example, the ring attachment can be designed as an injection-molded component. Manufacturing the ring attachment from steel is also possible. However, a one-piece design requires a high material and / or machining effort due to the complex structure of the ring attachment. Ring attachments made of steel can therefore preferably be designed in at least two parts, with a substantially axially extending part and a radially extending part that are joined together. However, an at least two-part design of the ring attachment is also possible for other materials.

[0029] The ring attachment and / or sealing race can also be designed in several parts and / or segments.

[0030] Preferably, two rows of tapered rollers are provided as the rolling element rows, arranged in an X or O configuration between the inner ring and the outer ring. By arranging the sealing arrangement according to the invention on both sides, an oil sump can be provided for both rows of tapered rollers. However, other bearing designs are also conceivable, for example, a three-roller slewing ring.

[0031] The problem is further solved by a wind turbine with a tower, a nacelle attached to the tower, and a rotor rotatably mounted on the nacelle. The rotor is mounted on the nacelle via the previously described rotor bearing. The rotor is rotationally fixedly connected to the outer ring of the rotor bearing, and the nacelle is connected to the inner ring.

[0032] Further advantageous embodiments can be found in the following description and the subclaims.

[0033] The invention is explained in more detail below with reference to the embodiments shown in the attached figures. Brief description of the drawings

[0034] Fig. 1 schematically shows a wind turbine according to the invention with a rotor mounted via a rotor bearing according to the invention, Fig. 2a schematically shows a first embodiment of the rotor bearing according to the invention in a sectional view, Fig. 2b schematically shows a detailed view of section X from Fig. 2a, Fig. 3 schematically shows a detailed representation of a second embodiment of the rotor bearing according to the invention with oil conveying means for relieving the second seal, Fig. 4 schematically shows a detailed representation of a third embodiment of the rotor bearing according to the invention with a further sealing element, wherein the second seal and the further sealing element are designed as co-directional, axially acting lip seals, Fig. 5 schematically shows a detailed representation of a fourth embodiment of the rotor bearing according to the invention with a further sealing element, wherein the second seal and the further sealing element are designed as oppositely directed, axially acting lip seals, and Fig. 6 schematically shows a detailed representation of a fifth embodiment of the rotor bearing according to the invention, in which the seal race can be fastened to the outer ring by means of the screw connection of the rotor, Fig.7 shows a schematic detail of a sixth embodiment of the rotor bearing according to the invention with a two-part ring attachment. Embodiments of the invention

[0035] In the various figures, identical parts are always provided with the same reference symbols and are therefore usually named or mentioned only once.

[0036] In Fig. 1 1 shows a wind turbine 100 according to the invention. The wind turbine 100 comprises a tower 110, a nacelle 120 attached to the tower 110, and a rotor 130 rotatably mounted on the nacelle 120. The rotor 130 is supported by a rotor bearing 1 according to the invention (cf. Fig. 2a to 6) is mounted on the nacelle 120. The rotor 130 is connected in a rotationally fixed manner to the outer ring 3 and the nacelle 120 is connected to the inner ring 2. The rotor 130 comprises a rotor hub 120 and a plurality of rotor blades 140 fastened to the rotor hub 120. The wind forces acting on the rotor blades 140 and the force of gravity are thus introduced via the rotor hub 120 into the outer ring 3 of the rotor bearing 1 and transferred via the rows of rolling elements 5 to the inner ring 2 and the nacelle 120.

[0037] In Fig. 2a and 2ba first embodiment of the rotor bearing 1 according to the invention is shown. The rotor bearing 1 has an inner ring 2 and an outer ring 3 which can be rotated relative to the inner ring 2 and which delimit a bearing interior 4. Two rows 5 of rolling elements which can roll between the bearing rings are arranged in the bearing interior 4. The rotor bearing 1 has a sealing arrangement 6 on each side for sealing the bearing interior 4 on one side, wherein the sealing arrangements 6 each have a first seal 7 which is connected in a rotationally fixed manner to the inner ring 2 and a sealing race 8 which is connected in a rotationally fixed manner to the outer ring 3 and on which a first sealing running surface 9 for the first seal 7 is formed. A ring attachment 10 is fastened to the inner ring 2 and engages around the sealing race 8 in the radial direction R.Furthermore, a second seal 11 is provided which acts between the seal race 8 and the ring attachment 10 and which delimits an annular space 14 formed between a radial outer surface 12 of the seal race 8 and a radial inner surface 13 of the ring attachment.

[0038] In the illustrated embodiment, two rows of tapered rollers are provided as rolling element rows 5, arranged in an O-arrangement between the inner ring 2 and the outer ring 3. The inner ring 2 is composed of two mutually sealed parts 2.1 and 2.2. Possible alternative bearing designs include, for example, a tapered roller bearing with an X-arrangement of the rollers, symmetrical or asymmetrical tapered roller bearings, or a 3-roller slewing ring.

[0039] To form an oil sump, the first seal running surface 9 has a smaller diameter than the largest diameter of a roller contact surface 15 for the row of rolling elements 5 on the outer ring 3. The first seal running surface 9 for the first seal 7 is thus attached to the seal running ring 8 in the radial direction R such that it is arranged in the region of the roller contact surface 15 formed on the outer ring 3 for the row of rolling elements 5. In the bearing interior 4, the introduced lubricating oil thus accumulates up to the roller contact surface 15, so that the rolling elements immerse themselves in the oil sump in a lower circumferential region of the bearing with each revolution and are wetted with lubricant.Due to the seal race 8 with a radially inwardly projecting section, on which the seal running surface 9 is arranged, an oil sump forms in the raceway system, which ensures sufficient wetting of the rolling contacts and sliding guides in the bearing even in the event of an oil supply failure. The maximum filling height H of the oil sump is given in . Fig. 2b marked by a dashed line.

[0040] As in Fig. 2bThe ring attachment 10 is shown to have an outlet 16 for connecting an oil return line, said outlet having a flow area which is at least partially located further outward in the radial direction R than a sealing gap 17 of the second seal 11. In the exemplary embodiment shown, the outlet takes place in the radial direction R. The rotor bearing is installed such that the outlet 16 is located in the lowest circumferential section in the vertical direction in order to ensure effective oil drainage. The ring attachment 10 is preferably trough-shaped in the area of the outlet 16 with a flank rising towards the second seal 11. The outlet 16 is preferably located below the second seal 11, even with the axial inclination of the rotor bearing, which is usually approximately 6°, so that the latter is not loaded by any oil present, but only by splash oil.The drain 16 is thus arranged in the region of a recess 26 formed in the radial inner surface of the ring attachment, so that the further sealing element 22 lies above a backflow level defined by the recess 26.

[0041] By connecting the annular space 14 between the first seal 8 and the second seal 11 to a return line of the oil lubrication system of the rotor bearing 1, a drainage system is created. The return of the leaked oil to the oil lubrication system can be achieved actively through negative pressure or passively through a geodetic height difference. Preferably, a drain 16 is provided on each of the seal assemblies 6 on either side of the bearing. The oil is supplied and removed via a supply system connected to the stationary inner ring 2 via pipes or hoses. Overfeeding of the bearing must be reliably avoided, even in the event of a monitoring device failure. Ventilation of the bearing must also be ensured.

[0042] Due to the removal of the leakage oil, a certain amount of leakage oil flow may be tolerated or even desirable. This reduces the required seal preloads and the resulting rotational resistance. Furthermore, seal wear is minimized and the service life of the seals 7, 11 is increased, which contributes to reduced maintenance requirements for the wind turbine 100.

[0043] In the annular space 14, a drip edge 18 is formed on the radial outer surface 12 of the seal race 8 in front of the second seal 11 to separate any entrained oil. The drip edge 18 is preferably arranged in front of the further sealing element 22. By providing a drip edge 18, simpler and more cost-effective seal types can be used for the second seal 11.

[0044] Both seals 7, 11 can be designed to seal radially or axially (with respect to the bearing axis A of the rotor bearing). In principle, both seals 7, 11 can be designed identically. However, preferred embodiments are those in which the first seal 7 bears against the first seal running surface 9 with a first lip preload that is greater than a second lip preload of the second seal 11. As a result, the first seal 7 forms a main seal and the second seal 11 a secondary seal. In the illustrated embodiment, it is preferably provided that the first seal 7 is designed as a radially acting main seal and the second seal 11 as an axially acting secondary seal 11.

[0045] Preferably, the first seal 7 is designed as a non-endless, joined lip seal. Acrylonitrile butadiene rubber (NBR) or hydrogenated acrylonitrile butadiene rubber (HNBR) is preferably used as the sealing material for the first seal 7.

[0046] The second seal 11 is preferably made as a dust seal, for example, from Buna-N. Alternatively, the second seal 11 can also be made of NBR or HNBR, for example.

[0047] In order to increase the sealing effect, spring-assisted sealing systems such as finger spring seals, in particular for the first seal 8, or felt and / or labyrinth seals can also be used.

[0048] The first seal 7 can, as in Fig. 2bAs shown, the seal 7 is clamped axially against the inner ring 2 by means of the ring attachment 10. For this purpose, the ring attachment 10 is preferably attached to the inner ring 2 via a screw connection and sealed against it. When the screws are tightened, the seal 7 is clamped in a radial shoulder of the inner ring 2 and thereby simultaneously positioned radially.

[0049] In the illustrated embodiment, the first seal 7 and the second seal 11 are held in position by the ring attachment 10, and the seal race 8 is formed with both the first seal running surface 9 for the first seal 7 and a second seal running surface 19 for the second seal 11. The advantage of this solution is that only the ring attachment 10 needs to be removed to replace the seals.

[0050] The seal race 8 is preferably fixed to the outer ring 3 by means of a screw connection. Through-bolts can also be used to simultaneously fasten one seal race 8 on each side of the bearing 1. However, the seal race can also be manufactured in one piece with the outer ring.

[0051] For centering, axially acting engagement means 20 are provided on the ring attachment 10 and the sealing race 8, which engage with complementary engagement means 21 on the inner ring 2 and correspondingly on the outer ring 3. Fig. 2a and 2b In the embodiment shown, the ring attachment 10 has an axial projection 20 which axially engages in a front-side groove 21 on the inner ring 2 and thus prevents radial displacement of the ring attachment 10. Similarly, the sealing race 8 has a stop edge 20 which engages in a front-side shoulder 21 on the outer ring 3.

[0052] The seal race 8 is - as in Fig. 2b shown - preferably fastened to the outer ring 3 by means of a screw connection and sealed against the outer ring 3 with an O-ring which is arranged radially inside the screw connection.

[0053] The seal race 8 is preferably made of steel, which is hardened at least in the region of the first seal running surface 9 to reduce seal wear. However, the seal race can also be made of another metal or a plastic material, for example.

[0054] The ring attachment 10 is preferably made of a plastic material. However, a steel construction is also conceivable and possible.

[0055] When made of steel, the ring attachment 10 and the sealing race 8 can be designed as forged rings, as cast or built rings, split or in one piece.

[0056] In the Fig. 2a In the illustrated embodiment, the sealing arrangement 6 is designed identically on both sides of the bearing. In an alternative embodiment, however, the sealing arrangements 6 on the two sides of the bearing can also be designed differently. For example, an additional sealing element (cf. Figs. 4 and 5 ) may be provided, or an oil collection tank may be provided instead of an oil return.

[0057] Fig. 3 shows a second embodiment of the rotor bearing 1 according to the invention. In contrast to the first embodiment, the second seal 11 is arranged to act radially. Irrespective of its direction of action, the second seal 11 can be arranged as in Fig. 3 shown are held by the seal race 8. The second seal race 19 is then formed on the ring attachment 10.

[0058] Furthermore, Fig. 3In contrast to the first embodiment, an axial drain 16 in the ring attachment 10 for connection to an oil return.

[0059] Furthermore, oil conveying means 24 are provided on the radial outer surface 12 of the seal race 8, which are suitable for conveying oil entrained during rotation of the outer ring 3 in a preferred direction of rotation away from the second seal 11. The radial outer surface 12 is then designed such that entrained oil is conveyed away from the second seal 11. As shown in Fig. 3 As shown, the oil conveying means 24 can be formed, for example, as a helical groove 25 in the radial outer surface 12 of the seal race 8. However, inclined lamellae are also conceivable as the oil conveying means 24.

[0060] Otherwise, the statements regarding the first embodiment apply accordingly to the second embodiment.

[0061] In Fig. 4A third embodiment of the rotor bearing according to the invention is shown. The third embodiment differs from the first embodiment essentially in that, to relieve the load on the second seal 11, at least one further sealing element 22 is provided between the first seal 7 and the second seal 11, which divides the annular space 14 into two chambers.

[0062] The second seal 11 and the further sealing element 22 are designed as axially acting lip seals with an axially aligned lip preload. Furthermore, the chamber between the further sealing element 22 and the second seal 11 is equipped with a further outlet 27 in the ring attachment 10. In this way, a three-stage sealing system is created with a second oil collection chamber, which can be connected to a collecting container or the oil return via the further outlet 27. In this way, the remaining leakage volume flow can be further reduced. Advantageously, the return is connected to a check valve so that no oil can flow back from the return into the second chamber.

[0063] A further optimization option is to apply positive or negative pressure to the first and / or second oil collection chamber. For the lip seals with the same orientation according to Fig. 4The additional sealing element 22 is relieved by an overpressure in the second chamber, and the flow direction of the leakage volume flow is directed toward the first chamber. The sealing effect and frictional torque can be optimized through a favorable combination of overpressure / underpressure in the two oil collection chambers and the arrangement of the lip seal.

[0064] Fig. 5 shows a fourth embodiment of the invention that differs from that shown in Fig. 4 The sealing element 22 differs from the illustrated embodiment essentially in that the second seal 11 and the further sealing element 22 are designed as oppositely directed, axially acting lip seals. In this sealing arrangement, an overpressure in the second oil collecting chamber formed between the seals increases the sealing effect of both seals. The sealing lips are arranged such that the associated sealing gap is closed by the overpressure.

[0065] Otherwise, the statements regarding the first embodiment apply accordingly to the third and fourth embodiments.

[0066] The Fig. 6 The fifth embodiment shown differs from the first embodiment in Fig. 2b in that the seal race 8 extends radially into the area of the fastening holes 23 in the outer ring 3. The fastening holes 23 primarily serve to fasten the rotor bearing to the rotor of a wind turbine using fastening screws 28. In the illustrated embodiment, the seal race 8 can be clamped to the adjacent structure using this standard screw connection when assembling the rotor. This has the advantage that fewer and smaller screws and holes need to be made in the rotating ring for assembly, while the dimensional accuracy of the seal race 8 is still ensured in the clamped state.

[0067] Otherwise, the statements regarding the first embodiment apply accordingly.

[0068] Fig. 7 shows a sixth embodiment of the rotor bearing according to the invention, which differs from the first embodiment in that the ring attachment 10 is formed in two parts. The ring attachment comprises a substantially radially extending first ring and a substantially axially extending second ring, which are joined together in a corner region and sealed against each other. A screw connection 29, for example, can be used to join the rings. However, other joining methods, such as welding or gluing, are also conceivable.

[0069] The at least two-part design of the ring attachment 10 has the advantage that the complex shape of the ring attachment 10 can be manufactured more cost-effectively, assembly is simplified, and the fit of the seals 7, 11 can be better controlled. In an alternative embodiment, the split ring attachment 10 can also be designed in segments.

[0070] Otherwise, the statements regarding the first embodiment apply accordingly. List of reference symbols

[0071] 1 Rotor bearing 2, 2.1, 2.2 Inner ring 3 Outer ring 4 Bearing interior 5 Rolling element row 6 Seal arrangement 7 First seal 8 Seal race 9 First seal running surface 10 Ring attachment 11 Second seal 12 Radial outer surface 13 Radial inner surface 14 Annular space 15 Roller contact surface 16 Drain 17 Sealing gap 18 Drip edge 19 Second seal running surface 20 Engagement means 21 Complementary engagement means 22 Sealing element 23 Mounting holes 24 Oil feed means 25 Groove 26 Recess 27 Drain 28 Mounting screw 29 Screw connection 100 Wind turbine 110 Tower 120 Nacelle 130 Rotor 140 Rotor blade 150 Rotor hub Rradial direction HFilling height ALearing axis

Claims

1. Rotor bearing for a wind turbine (100) having an inner ring (2) and an outer ring (3) rotatable relative to the inner ring (2) which delimit a bearing interior (4) in which at least one row (5) of rolling elements which can roll between the bearing rings (2, 3) is arranged, and having sealing arrangements (6) for sealing the bearing interior (4) on one side in each case, wherein at least one of the sealing arrangements (6) has a first seal (7) connected in a rotationally fixed manner to the inner ring (2) and a seal race ring (8) connected in a rotationally fixed manner to the outer ring (3), on which a first seal running surface (9) for the first seal (7) is formed, wherein an annular attachment (10) is fastened to the inner ring (2) and a second seal (11) acting between the seal race ring (8) and the annular attachment (10) is provided, characterized in that the annular attachment (10) embraces the seal race ring (8) in the radial direction (R) and the second seal (11) delimits an annular space (14) formed between a radial outer surface (12) of the seal race ring (8) and a radial inner surface (13) of the annular attachment, wherein an outlet (16) for connecting an oil return is provided in the annular attachment (10) with a flow sectional area which is arranged at least partially further outwards in the radial direction (R) than a sealing gap (17) of the second seal (11).

2. Rotor bearing according to claim 1, characterized in that, in order to form an oil sump, the first seal running surface (9) has a smaller diameter than the largest diameter of a roller contact surface (15) for the row (5) of rolling elements on the outer ring (3).

3. Rotor bearing according to claim 1 or 2, characterized in that a drip-off edge (18) is formed on the radial outer surface (12) of the seal race ring (8) in the annular space (14) upstream of the second seal (11) for tearing off entrained oil.

4. Rotor bearing according to one of claims 1 to 3, characterized in that the first seal (7) is axially clamped against the inner ring (2) by means of the ring attachment (10).

5. Rotor bearing according to one of claims 1 to 4, characterized in that the first (7) and the second seal (11) are held in position by the ring attachment (10) and a second seal running surface (19) for the second seal (11) is formed on the seal race ring (8).

6. Rotor bearing according to one of claims 1 to 5, characterized in that the first seal (7) bears against the first seal running surface (9) with a first lip preload which is greater than a second lip preload of the second seal (11).

7. Rotor bearing according to one of claims 1 to 6, characterized in that axially acting engagement means (20) are provided on the ring attachment (10) and / or the seal race ring (8) for centering, which engagement means are in engagement with complementary engagement means (21) on the inner ring (2) and / or correspondingly on the outer ring (3).

8. Rotor bearing according to one of claims 1 to 7, characterized in that the seal race ring (8) is fastened to the outer ring (3) by means of a screw connection and is sealed with respect to the outer ring (3) by an O-ring which is arranged radially on the inside of the screw connection.

9. Rotor bearing according to one of claims 1 to 8, characterized in that at least one further sealing element (22) is provided between the first seal (7) and the second seal (11) to relieve the second seal (11) and subdivides the annular space (14).

10. Rotor bearing according to claim 9, characterized in that the second seal (11) and the further sealing element (22) are designed as axially acting lip seals with an axially equal or oppositely directed lip preload.

11. Rotor bearing according to claim 3 and claim 9 or 10, characterized in that a further outlet (27) is provided in the ring attachment (10) between the further sealing element (22) and the second seal (11).

12. Rotor bearing according to one of claims 1 to 11, characterized in that the outer ring (3) has fastening bores (23) for fastening the rotor bearing (1) to a rotor (130) of a wind turbine (100) by means of fastening screws (28) and the seal race ring (8) extends in the radial direction (R) into the region of the fastening bores (23) for clamping the seal race ring (8) when the rotor (130) is mounted.

13. Rotor bearing according to one of claims 1 to 12, characterized in that the seal race ring (8) is made of steel and is hardened at least in the region of the first seal running surface (9).

14. Rotor bearing according to one of claims 1 to 13, characterized in that the ring attachment (10) is made of a plastic material.

15. Rotor bearing according to one of claims 1 to 14, characterized in that two rows of tapered rollers are provided as rolling element rows (5), which are arranged in an X or an O arrangement between the inner ring (2) and the outer ring (3).

16. Wind energy installation having a tower (110), a nacelle (120) fastened to the tower (110) and a rotor (130) rotatably mounted on the nacelle (120), characterized in that the rotor (130) is mounted on the nacelle (120) via a rotor bearing (1) according to one of claims 1 to 15, the rotor (130) being connected to the outer ring (3) and the nacelle (120) being connected to the inner ring (2) in a rotationally fixed manner.