BE1028243B1 - Rotor bearing for a wind turbine and wind turbine - Google Patents

Abstract

The invention relates to a rotor bearing for a wind turbine (100) with an inner ring (2) and an outer ring (3) which can be rotated relative to one another and delimit a bearing interior (4) in which at least one row of rolling elements (5 ) is arranged, and with an outlet (6) for discharging lubricating oil emerging from the bearing interior (4), the bearing interior (4) being designed to be open towards the drain (6) so that lubricating oil from the bearing interior (4) is depressurized can be discharged via the drain (6), as well as a wind turbine with such a rotor bearing (1).

Description

-1- BE2020 / 5280 Rotor bearing for a wind energy installation and wind energy installation PRIOR ART The invention relates to a rotor bearing for a wind energy installation according to the preamble of claim 1 and a wind energy installation according to the preamble of claim 12.

Rotor bearings of wind turbines serve to divert the forces and torques of the rotating rotor hub into the tower and into the foundation of the wind turbine and at the same time enable torque to be transmitted into the drive train to the generator. The rotor bearing can be designed as a moment bearing or as a plurality of distributed bearings - for example as adjusted tapered roller bearings or fixed / loose bearings. Roller bearings with at least one inner ring and one outer ring are usually used as rotor bearings, which enable the rotor to rotate with respect to the nacelle, in that one of these components is non-positively connected to the outer ring and the other to the inner ring. Grease, oil or otherwise lubricated rolling elements between the inner and outer ring enable the rotational movement.

Due to the high forces and torques to be transmitted by the rotor hub, it is advantageous for the design of the aforementioned bearings if the outer ring is connected to the rotating rotor hub and the stationary inner ring is connected to the nacelle - the nacelle. Such bearings are usually designed as grease-lubricated rotor bearings, since grease-lubricated bearings are less prone to leakage and require less maintenance. For oil lubrication, it has so far not been possible to achieve a satisfactory seal, especially with externally rotating rotor bearings. The advantages of oil lubrication are, on the one hand, that the oil can be filtered with circulating lubrication so that particles in the lubricant can be reduced from rolling over, and on the other hand, the possibility of active temperature control of the oil so that the temperature of the bearing is better adjusted and If necessary, other, additional cooling / heating systems can be dispensed with.

From DE 10 2017 107 553 A1 a tapered roller bearing with an inner ring, an outer ring and two rows of tapered rollers, which are shown in FIG

Lo. BE2020 / 5280 an O-arrangement between the inner ring and the outer ring are known. The gap between the inner ring and the outer ring is sealed on at least one side of the tapered roller bearing by a sealing arrangement which comprises a main seal connected non-rotatably to the inner ring as well as a sealing raceway connected to the outer ring in a rotationally fixed manner, the sealing raceway having a sealing surface for the main one - seal forms. Furthermore, the clamping ring with which the main seal is held carries a dust protection seal, which protects the main seal from contamination from the outside. A disadvantage of such a sealing arrangement is that, when the bearing is lubricated with oil, and in particular under load with an upright column of oil, it is not possible to reliably prevent oil from escaping through both seals.

To improve the tightness, an oil-lubricated roller bearing for mounting the rotor of a wind power plant was proposed in WO 2012/136632 A1, which has a shaft seal that separates a bearing interior from the bearing exterior, and a clamping arrangement for axially fixing the shaft seal, which has a drain for oil. As a result, lubricating oil that has passed through the shaft seal can be drained off before it escapes to the outside through the dust protection seals that are also provided. However, it is disadvantageous that the fill level of the lubricating oil in the bearing has to be set in a complex manner, in particular to avoid overfeeding the bearing with lubricating oil, which leads to deteriorated running properties and an increased amount of leakage oil.

DISCLOSURE OF THE INVENTION The object of the invention is therefore to specify a rotor bearing for a wind turbine and a wind turbine with a rotor bearing in which the sealing of an oil-lubricated bearing interior is improved and at the same time the permanent supply of the bearing interior with a fixed amount of lubricating oil is simplified.

This object is achieved by a rotor bearing for a wind turbine with the features of claim 1 and a wind turbine with the features of claim 12 Limit the interior of the bearing in which at least one row of rolling elements that can roll between the bearing rings

23. BE2020 / 5280 bodies are arranged, and with an outlet for the discharge of lubricating oil escaping from the bearing interior. According to the invention it is provided that the bearing interior is designed to be open towards the drain, so that lubricating oil can be discharged from the bearing interior without pressure via the drain. The open design of the interior of the bearing towards a drain ensures that overfeeding of the rotor bearing with lubricating oil is practically ruled out, even if the monitoring devices fail. Excess lubricating oil is discharged from the interior of the warehouse without pressure via the overflow and the drain. At the same time, the open design ensures that the rotor bearing is ventilated.

The interior of the bearing is preferably fluidically connected to the drain via at least one overflow that is non-rotatably connected to the outer ring and that, in the installed position of the rotor bearing, defines a fill level of at least one oil sump formed in the interior of the bearing. In the installed position of the rotor bearing, the geodetic height of the overflow defines a maximum fill level of at least one oil sump formed in the interior of the bearing. This ensures reliable operation and a high degree of tightness of the rotor bearing regardless of the amount of lubricant supplied and in all operating states - such as, for example, unbalanced states - without the need for a special measuring or regulating device for the oil system.

The use of an overflow towards the drain has the additional advantage that an oil sump is formed without lubricating oil accumulating on a seal. The oil sump gives the oil-lubricated rotor bearing advantageous emergency running properties in the event of a failure of the lubricant supply. The seals in the rotor bearing according to the invention are thus only loaded by spray oil and not by a standing oil column, as a result of which the tightness of the bearing is improved.

An oil treatment unit and a tank are preferably connected to the drain, from which the lubricating oil can be fed back to the interior of the bearing via a pump. The oil processing unit preferably comprises a filter and / or a temperature control device for active temperature control of the interior of the warehouse. In this way, the lubricating oil can be filtered and particles can be prevented from rolling over. Furthermore, the temperature of the bearing can be set better, for example by means of active oil cooling, and other cooling systems, for example water-based or air-based, can be dispensed with if necessary

"4- BE2020 / 5280. Oil heating for starting up the wind energy installation at low ambient temperatures is also conceivable. Condition monitoring is also possible, for example by monitoring the temperature and particles - even remotely.

In preferred embodiments, the rotor bearing is designed as a double-row tapered roller bearing or as an axial-radial roller bearing. One of the bearing rings is designed as a so-called nose ring, which is partially encompassed by a multi-part second bearing ring including several rows of rolling elements between the bearing rings. These bearing designs allow the absorption of radial and axial forces as well as tilting moments as they occur on rotor bearings of wind turbines Rows of rolling elements are formed and an oil catch ring is connected non-rotatably to each of the two sides. For the formation of an oil sump, the oil collecting rings can extend inward in the radial direction beyond the radially outer edges of the raceways. The oil catch rings can be designed in one piece with the outer ring, or they can be fixed to the outer ring as one or more additional rings. The oil catch rings preferably widen the outer ring and provide a trough-shaped receptacle for lubricating oil. For this purpose, the oil catch rings preferably have an essentially axially extending section and an essentially radially extending section on the edge. Due to the radial inward extension of the oil catch rings, a back pressure of lubricating oil into the area of the raceways is achieved. The rolling elements are at least partially immersed in the oil sump with each cycle and distribute the lubricating oil in the interior of the bearing during further rotation. According to the invention, the oil lubrication and return of the oil take place in such a way that even if the power supply or the pumps fail, no leakage emerges from the bearing, the return of excess oil, for example into a tank, continues and the bearing continues to operate at least for a limited period of time is possible.

At least one of the oil collecting rings preferably forms the at least one overflow. The lubricating oil is then dammed up on the inside of the oil catch ring in the oil sump and runs off on the outside to the drain.

-5- BE2020 / 5280 It is particularly preferable for the two oil sumps to be connected to one another via at least one channel that traverses the outer ring. Such a channel allows the exchange of lubricating oil between the two oil sumps. In the case of an installation situation of the bearing with a stationary outer ring, a channel passing through the outer ring can be sufficient to compensate for the filling heights of the two oil sumps during operation.

When the rotor bearing is designed as an external rotor, a plurality of channels passing through the outer ring for connecting the two oil sumps are preferably arranged distributed over the circumference of the outer ring. As the outer ring revolves, the channels dip one after the other into the area of the oil sumps. For the duration of the immersion, each channel connects the two oil sumps to one another to compensate for their filling heights. After leaving the oil sumps, the channels empty again, preferably in the direction of their lower end.

Rotor bearings can be installed with an inclination to the horizontal in order to move the rotor blades further away from the tower of the wind energy installation as they rotate and to exclude contact between the blade and tower even under high loads. This inclination of the rotor bearing axis can advantageously be used to convey the oil to the generator side and to discharge it there.

When the rotor bearing is designed as an external rotor, the oil is preferably supplied by means of bores or nozzles made in the stationary inner ring.

The connection of the oil sumps on both sides of the rotor bearing allows designs of the rotor bearing that only have lubricating oil connections on the generator side and drainage connections on both sides. This means that the majority of the lines and pumps from the hub / rotor side can be dispensed with. The risks of possible leaks, pump failures and repairs are reduced. A solution that only has lubricating oil and drainage connections on the generator side is particularly advantageous, as a result of which line guides and pumps on the hub side can be completely dispensed with.

In preferred embodiments, the rotor bearing has an overflow only on one side and the bearing interior is closed on the other side of the rotor bearing by means of at least one seal. By connecting the two oil sumps by means of at least one channel, their filling levels can be compensated for. A one-sided overflow can

-6- BE2020 / 5280 are sufficient to define a common fill level for both oil sumps. In this way, a standing oil column on the seal of the bearing interior can also be avoided on the side on which no overflow is provided.

In the installed position of the rotor bearing, the seal is preferably arranged above the fill level of the interconnected oil sumps, which is determined by the overflow. The barrel of the seal is usually adequately lubricated by splash oil. Such a stress-free seal has a high level of tightness, so that only a very small amount of leakage is to be expected. The seal is preferably used on the rotor side of the bearing, since the connections for the oil drainage are preferably attached on the generator side. A further advantage of this arrangement is given by the preferential direction of the oil flow towards the generator due to the inclination of the drive train. It is also conceivable, however, that one of the overflows is connected to the drain via at least one channel which traverses the outer ring. In this way, a rotor bearing in particular can be implemented in which an overflow is provided on both sides, but an outflow is only provided on one side. Lubricating oil that has escaped via an overflow on the rotor side, for example, can thus be returned to an outflow on the side of the nacelle through the channel in the outer ring.

In a preferred embodiment, a ring attachment is attached to the inner ring, which surrounds the oil trap ring forming the overflow in the radial direction and contains the drain, the ring attachment being sealed off from the oil trap ring. This embodiment is preferred for rotor bearings that are designed as external rotors. The drain is fixed to the stationary inner ring via the ring attachment.

The inner ring is preferably sealed directly or indirectly with respect to the outer ring on both sides of the bearing by a sealing system in each case, which comprises at least two seals, between which a drainage chamber for collecting leakage oil is formed. The formation of a multi-stage sealing system on both sides of the bearing further reduces the amount of lubricating oil that escapes from the bearing during operation.

In addition, it can be provided that the drainage chambers are connected to one another on both sides of the rotor bearing via at least one channel which traverses the outer ring. on

„7- BE2020 / 5280 in this way, the leakage oil that has escaped on both sides of the bearing can be drained away on one side. The continuous emptying of both drainage chambers during operation, which is made possible by this, reduces the load on the respective second seal. This increases the tightness of the bearing and extends the maintenance intervals.

As an alternative or in addition, the drainage chambers can be equipped in a lower circumferential area with an oil collecting container, which collects the leakage oil that occurs. Due to the small amount of leakage that remains, even small collecting tanks are suitable for collecting and temporarily storing the leakage over a long period of time.

The oil collecting tanks can either be emptied manually during regular maintenance work or, for example, using level-controlled pumps and the bearing can be relubricated with a corresponding amount of oil. The object is also achieved by a wind energy installation with a tower, a nacelle attached to the tower and a rotor rotatably mounted on the nacelle, the rotor being mounted on the nacelle via the rotor bearing described above. The rotor is preferably connected in a rotationally fixed manner to the outer ring and the nacelle to the inner ring of the rotor bearing. According to a preferred embodiment, the axis of rotation of the rotor bearing encloses an angle in the range from 2 ° to 10 ° with the horizontal, which promotes the flow of lubricating oil through a channel passing through the outer ring. Further advantageous embodiments can be found in the following description and the subclaims.

The invention is explained in more detail below with reference to the exemplary embodiments shown in the accompanying figures. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows schematically a wind turbine according to the invention with a rotor supported by a rotor bearing according to the invention, Fig. 2 shows schematically a first embodiment of the rotor bearing according to the invention in a sectional view with an oil overflow and several channels in the outer ring connecting the oil sumps on both sides of the rotor bearing,

8. BE2020 / 5280 FIG. 3 schematically shows a detailed representation of the rotor bearing according to FIG. 2, FIG - Systems are connected to one another by means of channels crossing the outer ring.

EMBODIMENTS OF THE INVENTION In the various figures, the same parts are always provided with the same reference symbols and are therefore usually only named or mentioned once. 1 shows a wind energy installation 100 according to the invention. The wind energy installation 100 comprises a tower 110, a nacelle 120 fastened 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. FIGS. 2 to 4 ) stored on the nacelle 120. The rotor 130 is preferably connected to the outer ring 3 and the nacelle 120 to the inner ring 2 in a rotationally fixed manner. The rotor 130 comprises a rotor hub 120 and several rotor blades 140 attached to the rotor hub 120. The wind forces acting on the rotor blades 140 and the force of gravity can thus be introduced via the rotor hub 120 into the outer ring 3 of the rotor bearing 1 and via the rows of rolling elements 5 be transferred to the inner ring 2 and the nacelle 120. A first exemplary embodiment of the rotor bearing 1 according to the invention for a wind energy installation is shown in FIG. 2. The rotor bearing 1 comprises an inner ring 2 and an outer ring 3, which can be rotated relative to one another and delimit a bearing interior 4. In the bearing interior 4, two rows of rolling elements 5 that can roll between the bearing rings 2, 3 are arranged here by way of example. The rotor bearing further comprises an outlet 6 for the discharge of lubricating oil emerging from the bearing interior 4. The bearing interior 4 is designed to be open towards the drain 6, so that lubricant oil can be discharged from the bearing interior 4 without pressure via the drain 6. The bearing interior 4 is fluidically connected to the drain 6 via an overflow 7 connected to the outer ring 3 in a rotationally fixed manner. In the illustrated installation position of the rotor bearing 1, the overflow 7 defines a filling level H of the oil sump 8 formed in the bearing interior 4.

-9- BE2020 / 5280 In the illustrated embodiment, two rows of tapered rollers are provided as rows of rolling elements 5, which are arranged in an O-arrangement between the inner ring 2 and the outer ring 3. The inner ring 2 is composed of two partial rings 2.1 and 2.2 sealed off from one another. Conceivable alternative bearing designs are, for example, a tapered roller bearing with an X arrangement of the rollers, symmetrical or asymmetrical tapered roller bearings, or axial-radial roller bearings such as a three-way rotary roller connection. The rotor bearing 1 is shown in FIG. 2 in the installed position. In the installation position, the axis of rotation A forms an angle in the range of 2 ° to 10 ° with the horizontal. In this way, the flow of lubricating oil through a channel crossing the outer ring can be promoted. With respect to the wind energy installation 100, the lower-lying side of the rotor bearing 1 (shown on the left in FIG. 2) is preferably arranged on the side of the nacelle 120 and the higher-lying side (shown on the right in FIG. 2) on the side of the rotor 130.

In the illustrated embodiment, the outer ring 3 is designed as a nose ring 9, on which two raceways 10 for rolling element rows 5 that can roll between the bearing rings 2, 3 are formed. On both sides of the outer ring 3, an oil collecting ring 11 is connected non-rotatably, which extends inward in the radial direction R in the radial direction R for the formation of an oil sump 8. The oil trap 11 shown on the left in FIG. 2 forms the overflow 7. As can be seen more clearly in the detailed illustration of the exemplary embodiment shown in FIG connected. In FIG. 2 it can be seen that these are arranged distributed over the circumference of the outer ring 3. After half a revolution of the outer ring 3, the channel 13 shown at the top in FIG. 2 dips into the oil sumps 8 and the channel 13 shown at the bottom in FIG. 2 is exposed. By providing oil catching grooves 20 in the oil catching rings 11, the channels 13 can be introduced at a sufficient distance from the hardened raceways 10. The channels 13 are preferably designed as through bores. The number and distribution of the channels 13 over the circumference is preferably selected so that, regardless of the angular position of the bearing rings 2, 3 with respect to one another, at least one channel

- 10 - BE2020 / 5280 provides a connection between the two oil sumps 8. In the case of a rotor bearing that is designed as an inner rotor, one channel 13 can accordingly be sufficient to permanently connect the oil sumps 8 to one another during operation to compensate for the fill levels.

The channels 13 preferably run essentially parallel to the axis of rotation A of the rotor bearing 1. Alternatively, the channels can also have a directional component in the circumferential direction of the rotor bearing. A pumping effect can be increased by a directional component of the channels selected as a function of a preferred direction of rotation of the rotor bearing, since the channels preferably empty in the direction of their lower end after emerging from the oil sumps. As can be seen in particular in FIG. 3, the rotor bearing 1 in the first exemplary embodiment has an overflow 7 on only one side and the bearing interior 4 is closed on the other side of the rotor bearing 1 by means of a seal 14. For this purpose, a height difference can be provided between the two oil collecting rings 11, which results from the installation position of the rotor bearing and / or the structural design of the two oil collecting rings 11. The seal 14 is used to ensure the unilateral, pressureless oil discharge in all, for example not balanced, transient operating states or also only briefly occurring operating states. This results in an asymmetrical hub-side and generator-side sealing system design, which ensures that - with the exception of small drainage / leakage quantities of the seal 14 - the amount of oil supplied can be safely discharged on the generator side. In the installation position of the rotor bearing 1 shown, the seal 14 is arranged above the filling level H of the oil sumps 8 connected to one another, which is determined by the overflow 7.

A drainage chamber 17 which is closed to the outside by at least one further seal and has a further drain 19 is arranged behind the seal 14. A collecting container, for example, which collects the leaked oil that has leaked out, can be connected to the drain 19. In the case of an external rotor, the drainage chamber 17 is preferably formed by a ring attachment which is fastened to the inner ring 2, surrounds the oil collecting ring 11 in the radial direction R and is sealed off from it. On the side of the overflow 7, the rotor bearing 1 also has a ring attachment 15 which is fastened to the inner ring 2 and which radially supports the oil collecting ring 11 forming the overflow 7

„11 - BE2020 / 5280 R and contains the drain 6. The ring attachment 15 is also sealed off from the oil collecting ring 11, forming a drainage chamber 17. The use of ring attachments as seal carrier rings is advantageous in terms of assembly and replacement of the seal on the system. As shown in FIGS. 2 and 3, the inner ring 2 is preferably sealed directly or indirectly from the outer ring 3 on both sides of the bearing 1 by a sealing system 16, which comprises at least two seals, between which a drainage chamber 17 is formed for collecting leakage oil. 4 shows a second exemplary embodiment of a rotor bearing 1 according to the invention. In contrast to the first exemplary embodiment, the drainage chambers 17 of the sealing systems 16 are connected to one another on both sides of the rotor bearing 1 via at least one channel 18 crossing the outer ring 3. The channel 18 can be provided in addition to and separately from a channel 13 which connects the oil sumps 8. Channel 13 is shown in dashed lines in FIG. 4, since it is arranged in a different plane of section of rotor bearing 1. Analogous to the channels 13 connecting the oil sumps 8, a plurality of channels 18 distributed over the circumference of the outer ring are also advantageous in the case of an external rotor.

The leakage oil discharged from the drainage chambers 17 can, if necessary, be returned to the lubricating oil circuit after being cleaned. Alternatively, the leakage oil can be collected and disposed of centrally. The remarks on the first exemplary embodiment also apply accordingly. According to an exemplary embodiment that is not shown, one of the overflows can also be connected to the drain via at least one channel that traverses the outer ring. The remarks on the first two exemplary embodiments also apply accordingly.

"492- BE2020 / 5280 List of Reference Numbers 1 rotor bearing 2 inner ring

2.1, 2.2 Partial rings 3 Outer ring 4 Bearing interior 5 Rolling element row 6 Outflow 7 Overflow 8 Oil sump 9 Nose ring 10 Raceway 11 Oil catch ring 12 Radial outer edge of the raceway 13 Channel 14 Seal 15 Ring top 16 Sealing system 17 Drainage chamber 18 Channel 19 Drainage drainage chamber 20 Oil catchment groove 100 Wind turbine 110 Tower 120 Nacelle 130 rotor 140 rotor blade 150 rotor hub R radial direction H filling level A bearing axis

Claims (15)

-13- BE2020 / 5280 PATENT CLAIMS 1. Rotor bearing for a wind turbine (100) with an inner ring (2) and an outer ring (3) which can be rotated relative to one another and which delimit a bearing interior (4) in which at least one row of rolling elements that can roll between the bearing rings (5) is arranged, and with an outlet (6) for discharging lubricating oil emerging from the bearing interior (4), characterized in that the bearing interior (4) is designed to be open towards the drain (6), so that lubricating oil from the storage interior (4) can be discharged without pressure via the drain (6). 2. Rotor bearing according to claim 1, characterized in that the bearing interior (4) is fluidically connected to the drain (6) via at least one overflow (7) which is non-rotatably connected to the outer ring (3) and which in the installed position of the rotor bearing (1 ) defines a filling level (H) of at least one oil sump (8) formed in the bearing interior (4). 3. Rotor bearing according to claim 1 or 2, characterized in that the outer ring (3) is designed as a nose ring (9) on which at least two raceways (10) for between the bearing rings (2, 3) rollable rows of rolling elements (5) are formed and to which an oil catch ring (11) is connected non-rotatably on both sides, which for the formation of an oil sump (8) each extend inwardly in the radial direction (R) beyond the radially outer edges (12) of the raceways (10) . 4. Rotor bearing according to claim 2 and 3, characterized in that at least one of the oil collecting rings (11) forms the at least one overflow (7). 5. Rotor bearing according to claim 3 or 4, characterized in that the two oil sumps (8) are connected to one another via at least one channel (13) which traverses the outer ring (3). 6. Rotor bearing according to claim 3 or 4, characterized in that the rotor bearing (1) is designed as an external rotor and a plurality of the outer ring (3) through cross channels (13) for connecting the two oil sumps (8) over the circumference of the Outer ring (3) are arranged distributed. "14 - BE2020 / 5280 7. Rotor bearing according to claim 2 and one of claims 5 or 6, characterized in that the rotor bearing (1) has an overflow (7) only on one side and the bearing interior (4) on the other side of the rotor bearing (1) is closed by means of at least one seal (14). 8. Rotor bearing according to claim 7, characterized in that the seal (14) in the installed position of the rotor bearing (1) is arranged above the fill level (H) of the interconnected oil sumps (8) determined by the overflow (7). 9. Rotor bearing according to one of claims 2 to 8, characterized in that one of the overflows is connected to the drain via at least one channel crossing the outer ring. 10. Rotor bearing according to one of claims 4 to 9, characterized in that a ring attachment (15) is attached to the inner ring (2), which surrounds the overflow (7) forming the oil collecting ring (11) in the radial direction (R) and the Contains drain (6), and the ring attachment (15) is sealed against the oil catch ring (11). 11. Rotor bearing according to one of claims 1 to 10, characterized in that the inner ring (2) is sealed against the outer ring (3) on both sides of the bearing (1) directly or indirectly by a sealing system (16) each, which has at least two Comprises seals, between each of which a drainage chamber (17) for collecting leakage oil is formed. 12. Rotor bearing according to claim 11, characterized in that the drainage chambers (17) on both sides of the rotor bearing (1) are connected to one another via at least one channel (18) which traverses the outer ring (3). 13. Wind power plant with a tower (110), a gondola (120) fastened to the tower (110) and a rotor (130) rotatably mounted on the gondola (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 12. 14. A wind power plant according to claim 13, wherein the rotor (130) with the outer ring (3) and the nacelle (120) with the inner ring (2) are rotatably connected. - 15 - 15. Wind energy plant according to claim 13 or 14, characterized in that the axis of rotation (A) of the rotor bearing (1) encloses an angle in the range of 2 ° to 10 ° with the horizontal.