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Title:
SEALING ARRANGEMENT FOR A MAIN BEARING OF A WIND TURBINE, BEARING ARRANGEMENT AND WIND TURBINE
Document Type and Number:
WIPO Patent Application WO/2019/155322
Kind Code:
A1
Abstract:
A sealing arrangement (34) for a main bearing (21) of a wind turbine (1). The sealing arrangement comprises a first seal (35) configured to be disposed on one axial side of the main bearing (21) and including a first O-ring (80), and a second seal (36), configured to be disposed on an axial side of the main bearing opposite the first seal. The second seal comprises a second O-ring (41) retained within a sealing holder assembly (40) that comprises multiple annular parts, including a ring- shaped inner fixture plate (43), configured to be disposed adjacent the main bearing, a ring-shaped basis fixture plate (44) and, on an axial side of the basis fixture plate opposite the inner fixture plate, a ring-shaped outer fixture plate (45). Preferably, at least one of the fixture plates (43, 44, 45) is formed of 4 to 8 arcuate plate parts.

Inventors:
FREESE, Gunar (Uhlenweg 12, Rostock, 18146, DE)
SUSEMIHL, Sabine (Büsumer Ring 25, Kühlungsborn, 18255, DE)
Application Number:
IB2019/050703
Publication Date:
August 15, 2019
Filing Date:
January 29, 2019
Export Citation:
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Assignee:
SUZLON ENERGY LTD. (Shrimali Society, Near Shri Krishna ComplexNavrangptura 9, Ahmedabad, 380009, IN)
International Classes:
F03D80/70; F16C33/76
Foreign References:
CN206054199U2017-03-29
EP2754892A12014-07-16
CN103104617A2013-05-15
US20130322803A12013-12-05
Other References:
None
Download PDF:
Claims:
Claims :

1. A sealing arrangement (34) for a main bearing (21) of a wind turbine (1), the main bearing (21) being generally annular with respect to a rotor shaft (14) and adapted to be mounted to a main frame (22) of the wind turbine (1), the sealing arrangement comprising:

a first seal (34) configured to be disposed on one axial side of the main bearing (21) and including at least a first 0-ring (80); and

a second seal (36), configured to be disposed on an axial side of the main bearing (21) opposite the first seal (34) ;

wherein the second seal (36) comprises a sealing holder assembly (40) and at least a second O-ring (41) retained, in use, within the sealing holder assembly (40); and wherein the sealing holder assembly (40) comprises multi ple annular parts.

2. A sealing arrangement (34) according to claim 1, charac terized in that in the sealing holder assembly (40) com prises a ring-shaped inner fixture plate (43), configured to be disposed adjacent the main bearing (21), a ring- shaped basis fixture plate (44) and, on an axial side of the basis plate opposite the inner fixture plate (43), a ring-shaped outer fixture plate (45) .

3. A sealing arrangement (34) according to claim 1 or 2, characterized in that the internal diameter of the basis fixture plate (44) is less than that of the inner fixture plate (43) and/or the outer fixture plate (45), thereby defining an annular recess (46) for receiving and/or re taining the second O-ring (41) .

4. A sealing arrangement (34) according to claim 2 or 3, characterized in that the basis fixture plate (44) in cludes, on a radially outer side thereof, a radially out wardly projecting first flange (47), for engaging a radi ally inwardly projecting second flange or shoulder (48) on the main frame (22) .

5. A sealing arrangement (34) according to any of claims 2,

3 or 4, characterized in that the outer fixture plate

(45) includes a plurality of bolt holes (49) enabling bolting of the outer plate (45) to a radially inwardly projecting second flange or shoulder (48) on the main frame ( 22 ) .

6. A sealing arrangement (34) according to any of claims 2 to 5, wherein the inner fixture plate (43), the basis fixture plate (44) and/or the outer fixture plate (45) is formed of a plurality of arcuate plate parts.

7. A sealing arrangement (34) according to claim 6, charac terized in that, for the inner fixture plate (43), the basis fixture plate (44) and/or the outer fixture plate

(45), the number of plate parts lies in the range 4 to 8, more preferably 5 to 7, and is more preferably 6.

8. A sealing arrangement (34) according to claim 6 or 7, characterized in that, for each of the inner fixture plate (43), the basis fixture plate (44) and/or the outer fixture plate (45), a radially-extending abutment surface (55-1 to 55-6) of two adjacent plate parts is angularly offset from a radially-extending abutment surface of an adjacent fixture plate by a predetermined offset angle.

9. A sealing arrangement (34) according to claim 8, charac terized in that the offset angle is 360/2n degrees, where n is the number of plate parts.

10. A sealing arrangement (34) according to any of the pre ceding claims, characterized in that an annular brush ar rangement (50) is provided on an axial side of the outer fixture plate (45) opposite the basis fixture plate (44) .

11. A sealing arrangement (34) according to any of the pre ceding claims, characterized in that the second seal (34) or the annular brush arrangement (50) is disposed on the main bearing (21) so as to be, in use, windside on the wind turbine (1) .

12. A sealing arrangement (34) according to any of the pre ceding claims, characterized in that the second seal has a rectangular cross-section, for example with horizontal and vertical dimensions in the ratio c. 32:25.

13. A bearing arrangement (19) for a wind turbine (1), the wind turbine (1) having a rotor shaft (14) terminating in a hub (5), and a main frame (22), the bearing arrangement comprising :

a first main bearing (20), for example mounted to the front of the main frame (22) and nearest to the hub (5); and

a second main bearing (21), for example mounted to the main frame (22) and farthest from the hub (5);

wherein the second main bearing (21) includes a sealing arrangement (34) according to any of the preceding claims .

14. A bearing arrangement (19) according to claim 13, wherein the first main bearing (20) includes (i) a third seal (24) configured to be disposed on a one axial side of the first main bearing (20) and including at least a third 0- ring (28) and/or (ii) a fourth seal configured to be dis posed on an axial side of the first main bearing (20) op posite the third seal (25) and including at least a fourth 0-ring (31) .

15. A wind turbine (1), comprising:

a main frame (22) and at least one main bearing (20) adapted to be mounted to the main frame (22), the at least one main bearing being generally annular with re spect to a rotor shaft (14) of the wind turbine (1), wherein the at least one main bearing (20) includes a sealing arrangement (34) according to any one of claims 1 to 12; and/or

wherein the wind turbine (1) comprises a bearing arrange ment (19) according to one of claims 13 or 14.

Description:
SEALING ARRANGEMENT FOR A MAIN BEARING OF A WIND TURBINE , BEARING ARRANGEMENT AND WIND TURBINE

TECHNICAL FIELD

The invention relates to the sealing of bearings within a na celle of a wind turbine, and more particularly to a sealing arrangement for a main bearing of a wind turbine, a bearing arrangement and a wind turbine.

BACKGROUND

In equipment such as wind turbines, a rotor axis (e.g. hori zontal) defines an axis of rotation of a hub to which blades are attached. Prior to operation of the wind turbine, a rotor is mounted to a main frame of the wind turbine via a bearing arrangement. Typically, the bearing arrangement comprises a first (front or windside) main bearing and a second (rear or generator-side) main bearing, each being lubricated (e.g. with grease or oil) .

Each main bearing must be sealed to prevent loss of lubricant and/or contamination thereof by foreign materials (e.g. dirt and dust) .

Due to the limited amount of space in wind turbine housing or nacelle, difficulties arise for a maintenance engineer in ac cessing the bearing area and carrying out maintenance. In particular, a problem with known arrangements is that it can be very difficult to change/replace a seal (e.g. O-ring) without complete disassembly of the bearing.

The present invention seeks to overcome the aforementioned problems and provide an improved sealing arrangement for a main bearing of a wind turbine, bearing arrangement and wind turbine .

SUMMARY

According to one aspect of the invention there is provided a sealing arrangement for a main bearing of a wind turbine, the main bearing being generally annular with respect to a rotor shaft and adapted to be mounted to a main frame of the wind turbine, the sealing arrangement comprising: a first seal configured to be disposed on one axial side of the main bear ing and including at least a first 0-ring; and a second seal, configured to be disposed on an axial side of the main bear ing opposite the first seal; wherein the second seal compris es a sealing holder assembly and at least a second 0-ring re tained, in use, within the sealing holder assembly; and wherein the sealing holder assembly comprises multiple annu lar parts.

Preferably, the sealing holder assembly comprises a ring- shaped inner fixture plate, configured to be disposed adja cent the main bearing, a ring-shaped basis fixture plate and, on an axial side of the basis plate opposite the inner fix ture plate, a ring-shaped outer fixture plate.

Preferably, the internal diameter of the basis fixture plate is less than that of the inner fixture plate and/or the outer fixture plate, thereby defining an annular recess for receiv ing and/or retaining the second O-ring.

Preferably, the basis fixture plate includes, on a radially outer side thereof, a radially outwardly projecting first flange, for engaging a radially inwardly flanging second flange on the main frame. Preferably, the outer fixture plate includes a plurality of bolt holes enabling bolting of the outer plate to a radially inwardly flanging second flange on the main frame.

Preferably, the inner fixture plate, the basis fixture plate and/or the outer fixture plate is formed of a plurality of arcuate plate parts. Preferably, for the inner fixture plate, the basis fixture plate and/or the outer fixture plate, the number of plate parts lies in the range 4 to 8, more prefera bly 5 to 7, and is more preferably 6.

Preferably, for each of the inner fixture plate, the basis fixture plate and/or the outer fixture plate, a radially- extending abutment surface of two adjacent plate parts is an gularly offset from a radially-extending abutment surface of an adjacent fixture plate by a predetermined offset angle. Preferably, the offset angle is 360/2n degrees, where n is the number of plate parts.

Preferably, an annular brush arrangement is provided on an axial side of the outer fixture plate opposite the basis fix ture plate.

Preferably, the second seal or the annular brush arrangement is disposed on the main bearing so as to be, in use, windside on the wind turbine.

Preferably, the second seal has a rectangular cross-section, for example with horizontal and vertical dimensions in the ratio c . 32:25. According to another aspect of the invention there is provid ed a bearing arrangement for a wind turbine, the wind turbine having a rotor shaft terminating in a hub, and a main frame, the bearing arrangement comprising: a first main bearing, for example mounted to the front of the main frame and nearest to the hub; and a second main bearing, for example mounted to the main frame and farthest from the hub; wherein the second main bearing includes a sealing arrangement according to any of claims 1 to 12 of the appended claims, or as described and/or illustrated herein.

Preferably, the first main bearing includes (i) a third seal configured to be disposed on one axial side of the first main bearing and including at least a third O-ring and/or (ii) a fourth seal configured to be disposed on an axial side of the first main bearing opposite the third seal and including at least a fourth O-ring.

According to another aspect of the invention there is provid ed a wind turbine, comprising:

a main frame and at least one main bearing adapted to be mounted to the main frame, the at least one main bearing be ing generally annular with respect to a rotor shaft of the wind turbine, wherein the at least one main bearing includes a sealing arrangement according to any one of claims 1 to 12 of the appended claims, or as described and/or illustrated herein; and/or wherein the wind turbine comprises a bearing arrangement according to one of claims 13 or 14 of the ap pended claims, or as described and/or illustrated herein.

An advantage of the invention is to facilitate maintenance of a main bearing of a wind turbine. A further advantage is to facilitate replacement of a seal in a main bearing of a wind turbine.

A further advantage of the invention is that, in embodiments, prevention of loss of lubricant and/or contamination thereof by foreign materials (e.g. dirt and dust) is enhanced.

Further advantages of the invention, in embodiments, are as follows .

• Minimisation of milling procedures for the single parts, and affording the use of sheet materials in the manufac ture of plate parts. Also, lasercutting or milling may be used for fabrication.

• Materials for the sealing arrangements can be plastics, where appropriate, e.g. PA66 (Automotive); or alterna tively aluminium sheet may be used, thereby reducing weight in each case.

• Common parts can be used for each sealing diameter (in a typical system, four different bearings - and therefore sealing diameters - are in use) .

• Use of a standard sealing profile (25x32mm) , e.g. a closed seal version for initial wind turbine generator mounting, and/or an endless version for maintenance.

• The additional endless brushes reduce entry of dust from outside - for the lip seal a brushed band can be used easy mounting (standard use in heavy machine indus tries) .

• The sheet overlayer system provides a "labyrinth gasket" - affording an easy handling procedure for mounting and service in the small working space between main frame and mainshaft. BRIEF DESCRIPTION OF THE DRAWINGS

Further details of the invention will become apparent from the drawings according to the description. In the drawings:

Figure 1 (PRIOR ART) shows a known wind turbine;

Figure 2 shows a perspective, partially cut-away view of the interior of a nacelle and hub of a wind turbine, including a bearing arrangement according to an em bodiment of the invention;

Figure 3 shows in more detail the bearing arrangement of

Fig. 2;

Figure 4 is a cross-sectional view of the front main bearing

20 of Fig. 3;

Figure 5 is a cross-sectional view of the rear main bearing

21 of Fig. 3;

Figure 6 is a cross-sectional view of the second rear seal

36 of Fig. 5;

Figure 7 is a partial axial view of the second rear seal 34 of Fig. 6;

Figure 8 is a cross-sectional view of a preferred form of the brush arrangement 50 of Fig. 7;

Figure 9 is an axial view of the outer fixture plate 45 of

Figs 6 and 7;

Figure 10 is a perspective cross-sectional view of the seal ing holder assembly 40 of Fig. 6;

Figure 11 is a partially cut-away perspective view of the second rear seal 34 of Fig. 6;

Figure 12 shows a main bearing seal 60 according to another embodiment of the invention;

Figure 13 is a close-up perspective view of the seal 60 of

Fig. 12; Figure 14 shows a main bearing seal 60' according to another embodiment of the invention; and

Figure 15 is an alternative close-up perspective cross- sectional view of the seal 60' of Fig. 14.

DETAILED DESCRIPTION

Figure 1 (PRIOR ART) shows a known wind turbine 1 with multi ple blades. The wind turbine 1 includes a tower 3 and a na celle 2 rotatably mounted on the tower 3. The nacelle 2 com prises a nacelle cover 4 mounted on a main frame (not shown) , which will be discussed in further detail below. On a rotor shaft (not shown) inside the nacelle 2 a rotor 7 is arranged, which in turn comprises a hub 5 and at least one rotor blade 6 (here, three) .

Near the axis of the hub 5, an end portion or blade root 8 of blade 6 is retained in place, e.g. within jacket 9. In use, hub 5 is rotatable about the z-axis, and during installation, maintenance and/or calibration, blade 6 is rotatable about the x-axis. In this embodiment, the blade 6 is made of glass fibre. However, it will be appreciated that the blade 6 may be made of other materials, such as carbon or carbon compo sites.

Figure 2 shows a perspective, partially cut-away view of the wind turbine 1 of Fig. 1, according to an embodiment of the invention. Within each blade root 8 may be a pitch sensing system 10, coupled to a digital control system 11. For sens ing yawing of the nacelle 2, housed within the nacelle cover 4 may be a yaw sensing system 12, also coupled to a digital control system 11. Referring in particular to the nacelle 2 of Fig. 2, as is known, rotary motion is transferred, in use, indirectly from the hub 5 to a generator 13, for generating electrical power. That is, firstly, a main rotor shaft 14 mechanically couples the hub 5 to a gearbox 15. Further, a secondary rotor shaft 16 mechanically couples (an output gear of) the gearbox 15 to generator 13 via a fluid coupling 17. A mechanical braking system 18 is mounted can, in use, act upon secondary shaft 16 for reducing rotationally speed input to the generator 13.

Within the nacelle cover 4 and mounted to the main frame 22 is a (main) bearing assembly 19 consisting of a front main bearing 20 and rear main bearing 21; and main bearings 20 and 21 support main rotor shaft 14, in use, for rotation.

Figure 3 shows in more detail the bearing assembly 19 of Fig. 2. Suitably, the drive train arrangement is a so-called 4- point suspension arrangement with two main bearings (front main bearing 20 and rear main bearing 21) integrated in the main frame structure and supporting main rotor shaft 14 for rotation. The front main bearing 20 may comprise a tapered roller bearing and rear main bearing 21 may comprise an 0- ring seal arrangement.

Figure 4 is a cross-sectional view of the front main bearing 20 of Fig. 3. As can be seen, the front main bearing 20 com prises a first sealing arrangement 23, including a first front seal 24 and a first rear seal 25. The first front seal 24 comprises a first front bracket 26, attachable to the main frame 22 by bolts 27, and retaining a first front O-ring 28. Further, the first rear seal 25 comprises a first rear brack et 29, attachable to main frame 22 by at least one bolt 30, and retaining a first rear O-ring 31. Preferably, the front main bearing 20 includes a first upper pair of oil conveying grooves 32 and a lower pair of oil conveying grooves 33.

Figure 5 is a cross-sectional view of the rear main bearing 21 of Fig. 3. The rear main bearing 21 includes a second sealing arrangement 34 preferably comprising a second front seal 35 and a second rear seal 36. The second front seal 35 comprises a second front bracket 37, attachable via bolts 38 to a second front flange 39 of main frame 22, and retaining a second O-ring 80.

In this embodiment, second rear seal 36 comprises sealing holder assembly 40, attachable via bolts 41 to main frame 22, and retaining a second rear O-ring 41. The sealing holder as sembly 40 is an annular piece, preferably made of multiple annular sections, as will be described in further detail be low. Finally, in this embodiment, the second rear seal 36 further includes a V-seal 42.

Figure 6 is a cross-sectional view of the second rear seal 36 of Fig. 5. More particularly, the sealing holder assembly 40 comprises an inner fixture plate 43, a basis (middle) fixture plate 44 and an outer fixture plate 45. As can be seen in Fig. 6, the internal diameter of the basis fixture plate 44 is less than that of the inner fixture plate 43 and the outer fixture plate 45, thereby defining an annular recess 46 for receiving and/or retaining the second rear O-ring 41. Fur ther, the basis fixture plate 44 includes, on a radially out er side thereof, a radially-outwardly projecting first flange 47, for engaging a radially-inwardly projecting second flange or shoulder 48 on the main frame 22. In this embodiment, the outer fixture plate 45 includes a plurality of bolt holes 49 enabling bolting of the outer fixture plate 45 to the radial- ly-inwardly projecting second flange or shoulder 48 on the main frame 22.

Preferably, an annular brush arrangement 50 is attached on an axial side of the outer fixture plate 45 opposite the basis fixture plate 44. The brush arrangement 50 may comprise a brush ring 51, attachable to the outer fixture plate 45, e.g. by bolting, and annular brushes 52.

Figure 7 is a partial axial view of the second rear seal 34 of Fig. 6. Figure 7 shows the brush arrangement 50 bolted via bolt holes 53 in brush ring 51 to the outer fixture plate 45, and including brushes 52.

Figure 8 is a cross-sectional view of a preferred form of the brush arrangement 50 of Fig. 7.

Figure 9 is an axial view of the outer fixture plate 45 of Figs 6 and 7. As can be seen, the outer fixture plate 45 is formed of a plurality of arcuate plate parts 54-1 to 54-6. That is, in this embodiment, six plate parts 54-1 to 54-6 are used. However, it will be appreciated that another number of plate parts may be used, i.e. the number of plate parts may lie in the range 4 to 8, or more preferably 5 to 7 (while the use of a plurality of plate parts 54-1 to 54-6 is illustrated in relation to the outer fixture plate 45, it will be appre ciated that a similar or analogous structure may be used for the inner fixture plate 43 and/or the basis fixture plate 44) . As a result of the structure of Fig. 9, radially extend ing abutment surfaces 55-1 to 55-6 exist between adjacent plate parts. In embodiments, where multiple plate parts are used for each of the inner fixture plate 43, the basis fix ture plate 44 and/or the outer fixture plate 45, the radially extending abutment surface 55-1 of two adjacent plate parts 55-1, 55-2 is angularly offset from a radially extending abutment surface of an adjacent fixture plate (43 to 45) by a predetermined offset angle. In embodiments, the offset angle is 360/2n degrees, where n is the number of plate parts 55-1 to 55-6.

Figure 10 is a perspective cross-sectional view of the seal ing holder assembly 40 of Fig. 6. As can be seen, the annular recess 46 within sealing holder assembly 40 provides a recess for the receipt of the second rear O-ring 41. In this embodi ment, the second rear O-ring 41 has a resilient projecting flange 56 which aids in sealing of the main bearing as the flange 56 is urged into sealing contact with a portion (not shown) of the main bearing 21.

Figure 11 is a partially cut-away perspective view of the second rear seal 34 of Fig. 6. As can be seen, the second rear O-ring 41 is of generally rectangular cross-section and in this embodiment, the horizontal and vertical dimensions of the second rear O-ring 41 are 32 mm and 25 mm, respectively; alternatively, the horizontal and vertical dimensions of the second rear O-ring 41 may be in the ratio of c. 32:25.

Figure 12 shows a main bearing seal 60 according to another embodiment of the invention. The seal 60 comprises an upper annular bracket 61 with a generally hook shaped lower portion 62 and a lower annular bracket 63 with a generally hook shaped outer portion 64. A sealing ring 65, e.g. of L-shaped profile, is mounted to the upper and lower annular brackets 61, 63. That is, a first portion 66 engages a radially ex tending surface of the upper annular bracket 61, and a second portion 67 of the sealing ring 65 engages a circumferentially extending surface 68 of the lower annular bracket 63.

Figure 13 is a close-up perspective view of the seal 60 of Fig. 12. As can be seen, a metal tightening ring 69 disposed on the second portion 67 of sealing ring 65 can be used, in use, to tighten the sealing ring 65 onto the surface 68 of lower annular bracket 63.

Figure 14 shows a main bearing seal 60' according to another embodiment of the invention. In this embodiment, the upper annular bracket 61' and lower annular bracket 63' have dif ferent forms to those of Figs 12 and 13, so as to define a generally square recess 70 for receiving a sealing ring 65' . In addition, the sealing ring 65' may include an internal (substantially V-shaped) slot 71 for receiving a metal inner tightening ring 72. The seal 60' may further include a metal outer tightening ring 73 that is attachable to a surface of the upper annular bracket 61' .

Figure 15 is an alternative close-up perspective cross- sectional view of the seal 60' of Fig. 14. The disposition of the sealing ring 65' , outer tightening ring 73 and inner tightening ring 72 are shown in more detail. In addition, it can be seen that an abutting portion 74 of the sealing ring 65' includes V-grooves 75, to assist with sealing function. List of reference signs

1 wind turbine

2 nacelle

3 tower

4 nacelle cover

5 hub

6 rotor blade

7 rotor

8 blade root

9 j acket

10 pitch sensing system 11 digital control system 12 yaw sensing system

13 generator

14 main rotor shaft

15 gearbox

1 6 secondary rotor shaft

17 fluid coupling

1 8 mechanical braking system

1 9 bearing assembly

20 front main bearing

21 rear main bearing

22 main frame

23 first sealing arrangement

24 first front seal

25 first rear seal

2 6 first front bracket

27 bolt

2 8 first front O-ring

2 9 first rear bracket

30 bolt

31 first rear O-ring upper pair of oil conveying grooves lower pair of oil conveying grooves second sealing arrangement

second front seal

second rear seal

second front bracket

bolt

second front flange 39

sealing holder assembly

second rear O-ring

V-seal

inner fixture plate

basis fixture plate

outer fixture plate

annular recess

first flange

second flange

bolt hole

brush arrangement

brush ring

annular brushes

bolt hole

-1 to 54-6 plate part

-1 to 55-6 abutment surface

projecting flange

main bearing seal

' main bearing seal

upper annular bracket

' upper annular bracket

lower portion

lower annular bracket

' lower annular bracket

outer portion sealing ring

sealing ring

first portion

second portion

circumferentially extending surface metal tightening ring

square recess

slot

metal inner tightening ring

metal outer tightening ring

abutting portion

V-groove

second front O-ring