Description:TITLE OF INVENTION

A METHOD FOR REPAIRING A GEARBOX OF A WIND TURBINE

FIELD OF INVENTION

The present invention is directed to a method for repairing a gearbox of a wind turbine and a wheel stopper device for axially arresting of a planet wheel of a gearbox and for using said method.

BACKGROUND

In gearboxes of wind turbine wear and deformation in circlip was identified. This results in unwanted axial movement of a planet wheel. The damage of the circlip has several disadvantages namely wear of circlip. This failure mode requires removal of Gearbox from nacelle and service in workshop as per prior art

OBJECT OF THE INVENTION

It is one object of present invention to provide a method for repairing a gearbox of a wind turbine without replacing the gearbox.

SUMMARY OF THE INVENTION

The above-mentioned object should be solved by a first aspect of the present invention directed to a method for repairing a gearbox of a wind turbine and a second aspect of the present invention directed to a wheel stopper device as well as a third aspect of the present invention directed to a wind turbine.

The method for repairing a gearbox of a wind turbine comprising steps of:
- placing at least one gearbox side stopper plate between a torque arm cover of a gearbox and a first attaching point,
- pulling out of the torque arm cover,
- placing a wheel stopper device for axially arresting of a planet wheel of a gearbox,
- pushing in the torque arm cover and
- removing all stopper plates.

Advantageously, the present invention helps to avoid that a rotating planet wheel comes into contact with a stationary torque arm cover or with planet carrier which leads to an extended lifetime of a gearbox of a wind turbine. More advantageously, the wheel stopper device can be installed without disassembling the entire gearbox which reduces repairing time respectively an exchange of the complete gearbox. So the present invention provides a cost efficiency method for repairing a gearbox.

In a preferred embodiment of the method for repairing a gearbox of a wind tur-bine further comprising step of placing at least one rotor side stopper plate be-tween first attaching point and second attaching point.

In a preferred embodiment of the method for repairing a gearbox of a wind tur-bine, wherein the first attaching point is a bearing cover and the second attaching point is a shrink disk.

In a preferred embodiment of the method for repairing a gearbox of a wind tur-bine further comprising steps of:
- placing at least one gearbox side stopper plate between the torque arm cover and the bearing cover of gearbox,
- placing at least one rotor side stopper plate between the bearing cover and a shrink disc,
- disassembling of the bearing cover,
- pulling out of the torque arm cover,
- placing a wheel stopper device for axially arresting of a planet wheel of a gearbox,
- pushing in the torque arm cover,
- assembling the bearing cover and
- removing all stopper plates.

In a preferred embodiment of the method for repairing a gearbox of a wind tur-bine further comprising step of subsequently arresting movement of rotor side bearing for preventing damage of rotor side bearing when moving the torque arm cover toward rotor side bearing.

The second aspect of the present invention is directed to a wheel stopper device.

The wheel stopper device for axially arresting of a planet wheel of a gearbox and for using in said method, wherein the wheel stopper device having a mounting section for mounting the wheel stopper device to a ring gear and a contact section for contacting a planet wheel for avoiding axial movement of a planet wheel and wherein the wheel stopper device is ring shaped.

In a preferred embodiment of the wheel stopper device, the contact section dimensioned to cover in teeth area of planet wheel.

In a preferred embodiment of the wheel stopper device, the contact section dimensioned to cover in teeth area and body area of planet wheel.

In a preferred embodiment of the wheel stopper device, the contact section dimensioned to cover in teeth area and body area of planet wheel and in end region of contact section is arranged an additional ring for reducing friction between wheel stopper device and planet wheel.

In a preferred embodiment of the wheel stopper device, the additional ring made of polytetrafluoroethylene (PTFE) or ceramic or brass or any other equivalent material.

In a preferred embodiment of the wheel stopper device, the wheel stopper device is segmented device having at least two segments.

The third aspect of the present invention is directed to a wind turbine.

The wind turbine comprises a gearbox having said wheel stopper device.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be explained in more detail with respect to exemplary embodiments with reference to the enclosed drawings, wherein:

Figure 1 shows a wind turbine (prior art);

Figure 2 shows a detailed view rotor shaft and gearbox (prior art);

Figure 3 shows a method step according to a first embodiment of the method;

Figure 4 shows a further method step according to a first embodiment of the method;

Figure 5 shows a method step according to a second embodiment of the method;

Figure 6 shows a further method step according to a second embodiment of the method;

Figure 7 shows installed wheel stopper device according to a first embodiment;

Figure 8 shows a detailed view of wheel stopper device according to a first embodiment;

Figure 9 shows installed wheel stopper device according to a second embodiment and

Figure 10 shows installed wheel stopper device according to a third embodiment.

The foregoing and other aspects will become apparent from the following de-tailed description of the invention when considered in conjunction with the ac-companying drawing figures.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 depicts a schematic view of a wind turbine 1 with a tower 2 and a nacelle 3. Depending on given requirements the wind turbine 1 can be used for off-shore or onshore applications. The nacelle 3 is rotatable mounted on the tower 2 which is indicated by a double arrow at the tower 2. The nacelle 3 incorporates a number of components like a drive train chain 4 comprising a rotor shaft 5 (also known as slow-speed-shaft) connecting a rotor 6 with a gearbox 7. A high-speed-shaft 8 connects the gearbox 7 with a generator 9. The generator 9 is connected with a plurality of electrical components indicated by box 10. Further the nacelle 3 comprises a yaw system 11 for rotating the nacelle 3 indicated by double arrow at tower 2. The rotor 6 comprises three rotor blades 12 which are mounted to a hub body (not shown). Latter is connected to the rotor shaft 5 of the drive train chain 4. The rotor blades 12 are adjustably mounted on the hub body indicated by double arrows at the rotor blade 12. This is realized by means of pitch drives 13, said pitch drives (not shown) being part of a pitch system 13. The pitch system controls the rotor speed to given set points. By means of pitch-drives, the rotor blades 12 may be moved about a rotor blade axes into different pitch positions which is indicated by double arrows at the rotor blade 13. Said rotor blade 6 axis extends in an axial direction of the rotor blades 13. Each rotor blade 13 is con-nected to the hub body via its blade bearing (not shown). The nacelle 3 is covered by a nacelle cover 14. The hub body is covered by a spinner 15, wherein the hub body and spinner 11 forming a hub 16.

Figure 2 depicts a detailed cut-out view of a connection of the rotor shaft 5 to the gearbox 7 according to prior art. In this embodiment the rotor shaft 5 is connect-ed with an input shaft 17 of the gearbox 7 via a shrink disk 18. In a not shown embodiment, the present invention also works with a flange connection. Fur-thermore the gearbox 7 comprises beside other components a torque arm cover 19 connected to a ring gear 20 via a plurality of bolts 24. The ring gear 20 inter-acts with a planet wheel 21. The torque arm cover 19 is mounted to a rotor side bearing 22. Latter is sealed by a sealing (not shown) covered by a bearing cover (23).

Figures 3 and 4 depict a detailed cut-out view of Fig. 2 according to the first embodiment of the method for repairing a gearbox 7. According to the first embodiment, between the bearing cover 23 and rotor side bearing 22 is arranged at least one gearbox side stopper stopper plate 25 for holding the rotor side bearing 22 in place while pulling the torque arm cover 19 in direction to the bearing cover 23 (see Fig. 4). Here the bearing cover 23 functions as first attaching point. Before pulling the torque arm 19 in direction to the bearing cover 23, the bolts 24 has to be removed. After removing of the bolts 24 the torque arm cover will be pulled in direction to the bearing cover 23 until the torque arm cover 19 is attached to the bearing cover 23 as be shown in Fig. 4. In this configuration a gap 26 between the torque arm cover 19 and the ring gear 20 is provided. In this gap 26 will be placed one of the embodiments of a wheel stopper device 27, 27a, 27b (not shown), which will be explained in detail below. Depending on size and weight of the torque arm 19 the gearbox side stopper plate 25 can be designed differently. In one embodiment several gearbox side stopper plates 25 are ar-ranged circumference around the input shaft of the gearbox 7 between the bear-ing 22 and bearing cover 23. The gearbox side stopper plates 25 can be formed like a circular segment. According to this embodiment it is not necessary that the individual gearbox side stopper plates 25 having contact with beside arranged one. There can be arranged at least three gearbox side stopper plates 25, preferred at least four gearbox side stopper plates 25, more preferred at least six gearbox side stopper plates 25. Advantageously the individual gearbox side stopper plates 25 are arranged symmetrically. In another embodiment the gearbox side stopper plate 25 forms a closed ring. Therefore at least two segmented circular ring parts designed as gearbox side stopper plates 25. Preferred there can be arranged at least four gearbox side stopper plates 25, more preferred at least eight gearbox side stopper plates 25. Important is that the individual gearbox sided stopper plates 25 forming a closed ring for holding the bearing 22 in place while moving the torque arm 19 in direction to the bearing cover 23.

Figures 5 and 6 depict a detailed cut-out view of Fig. 2 according to the first embodiment of the method for repairing a gearbox 7. Compared to the first embodiment the second embodiment of comprises additional at least one rotor side stopper plate 28 for holding the bearing cover 23 in place after pulling the torque arm in direction to the shrink disk 18. The rotor side stopper plate 28 will be placed between bearing cover 23 and shrink disk 18. After removing the bolts 24 the torque arm cover 19 will be pulled in direction to the shrink disk 18 until the rotor side stopper plate 28 will be attached to the shrink disk 18. Here the shrink disk 18 functioned as second attaching point (see Fig. 6). In this configuration a gap 26 between the torque arm cover 19 and the ring gear 20 is provided. In this gap 26 will be placed one of the embodiments of a wheel stopper device 27, 27a, 27b (not shown), which will be explained in detail below. Depending on size and weight of the torque arm 19 the rotor side stopper plate 28 can be designed differently. In one embodiment several rotor side stopper plates 28 are arranged circumference around the bearing cover 23 between the bearing cover 23 and shrink disk 18. The rotor side stopper plates 28 can be formed like a circular segment. According to this embodiment it is not necessary that the individual rotor side stopper plate 28 having contact with beside arranged one. There can be arranged at least three rotor side stopper plates 28, preferred at least four rotor side stopper plates 28, more preferred at least six rotor side stopper plates 28. Advantageously, the individual rotor side stopper plates 28 are arranged symmetrically. In another embodiment the rotor side stopper plate 28 forms a closed ring. Therefore at least two segmented circular ring parts designed as rotor side stopper plates 28. Preferred there can be arranged at least four rotor side stopper plates 28, more preferred at least eight rotor side stopper plates 28. Important is that the individual rotor side stopper plates 28 forming a closed ring for holding the bearing 22 in place while moving the torque arm 19 in direction to the shrink disk 18.

Figure 7 depicts a mounted wheel stopper device 27 between the torque arm 19 and the ring gear 20. The wheel stopper device 27 is fixed through bolts 24 (not shown) at a mounting section 29. As can be seen, the wheel stopper device 27 restricts the axial movement of the planet wheel 21. This will be provided by a contact section 30 which contacts a planet wheel 21 for avoiding axial movement of a planet wheel 21. Optionally, at the contact section 30 can have a friction reducing coating. The wheel stopper device 27 is ring shaped and follows the contour of the ring gear 20. For an improved attachability the wheel stopper de-vice 27 can be segmented in at least two parts, preferably at least three parts, more preferably at least four parts. Same applies for all embodiments of the wheel stopper device 27, 27a, 27b.

Figure 8 depicts a detailed cross-sectional view of the wheel stopper device 27 according to the first embodiment. The wheel stopper device 27 comprises a mounting section 29 for mounting the wheel stopper device 27 to a ring gear 20 and a contact section 30 for contacting a planet wheel 21 for avoiding axial movement of a planet wheel 21. The contact section 30 is arranged offset to the mounting section 29. The upper surface of the planet wheel side of contact section 30 is angled and follows the contour of the planet wheel 21. Optionally, at this section of the contact section 30 a friction reducing coating may be applied.

Figure 9 depicts cut-out view according to Fig. 2 showing the installed wheel stopper device 27a according to a second embodiment. The wheel stopper device 27a is mounted between the torque arm 19 and the ring gear 20. The wheel stop-per device 27a is fixed through bolts 24 at a mounting section 29. As can be seen, the wheel stopper device 27a restricts the axial movement of the planet wheel 21. This will be provided by a contact section 30a which contacts a planet wheel 21 for avoiding axial movement of a planet wheel 21. Optionally, at the contact section 30a can be applied a friction reducing coating. The wheel stopper device 27a is ring shaped and follows the contour of the ring gear 20. For an improved attachability the wheel stopper device 27a can be segmented in at least two parts, preferably at least three parts, more preferably at least four parts. The second embodiment of the wheel stopper device 27a differs from the first embodiment in the contact section 30a. Latter extends over the teeth of the planet wheel 21 to the body of the same. A middle area of the contact section 30a is formed as a recess 31 which has neither contact to the wheel planet 21 nor to the teeth of the planet wheel 21. So the upper area of the contact section 30a may in contact with the teeth of the planet wheel 21 and the lower area of the contact section 30a may in contact with the body of the planet wheel 21 for restriction of axial movement of the planet wheel 21.

Figure 10 depicts cut-out view according to Fig. 2 showing the installed wheel stopper device 27b according to a third embodiment. The wheel stopper device 27b is mounted between the torque arm 19 and the ring gear 20. The wheel stop-per device 27b is fixed through bolts 24 at a mounting section 29. As can be seen, the wheel stopper device 27b restricts the axial movement of the planet wheel 21. This will be provided by a contact section 30a which contacts a planet wheel 21 for avoiding axial movement of a planet wheel 21. The wheel stopper device 27b is ring shaped and follows the contour of the ring gear 20. For an improved attachability the wheel stopper device 27b can be segmented in at least two parts, preferably at least three parts, more preferably at least four parts. The third embodiment of the wheel stopper device 27b differs from the second embodiment in the contact section 30b. At the end area of the contact section 30b is attached an additional anti-friction ring 32. This anti-friction ring 32 can be made of any suitable anti-friction material like of polytetrafluoroethylene (PTFE) or ceramic or brass or any other equivalent material. This further reduces the friction be-tween the wheel stopper device 27b and the planet wheel 21.

LIST OF REFERENCE SIGNS

1 wind turbine
2 tower
3 nacelle
4 drive train chain
5 rotor shaft
6 rotor
7 gearbox
8 high-speed-shaft
9 generator
10 electrical components
11 yaw system
12 rotor blades
13 pitch system
14 nacelle cover
15 spinner
16 hub
17 input shaft
18 shrink disk
19 torque arm cover
20 ring gear
21 planet wheel
22 rotor side bearing
23 bearing cover
24 bolts
25 gearbox side stopper plate
26 gap
27 wheel stopper device (first embodiment)
27a wheel stopper device (second embodiment)
27b wheel stopper device (third embodiment)
28 rotor side stopper plate
29 mounting section
30 contact section
30a contact section (second embodiment)
30b contact section (third embodiment)
31 recess
32 anti-friction ring

, Claims:We Claim:

1. A method for repairing a gearbox of a wind turbine comprising steps of:
- placing at least one gearbox side stopper plate (25) between a torque arm cover (19) of a gearbox (7) and a first attaching point (23),
- pulling out of the torque arm cover (19),
- placing a wheel stopper device (27, 27a, 27b) for axially arresting of a planet wheel (21) of a gearbox (7),
- pushing in the torque arm cover (19) and
- removing all stopper plates (25).

2. The method for repairing a gearbox of a wind turbine according to claim 1 comprising step of: placing at least one rotor side stopper plate (28) between first attaching point (23) and second attaching point (18).

3. The method for repairing a gearbox of a wind turbine according to claim 1 or 2, wherein the first attaching point (23) is a bearing cover and the second attaching point (18) is a shrink disc (18).

4. The method for repairing a gearbox of a wind turbine according one of the claims 1 to 3 comprising steps of:
- placing at least one gearbox side stopper plate (25) between the torque arm cover (19) and the bearing cover of gearbox (7),
- placing at least one rotor side stopper plate (28) between the bearing cover and a shrink disc (18),
- disassembling of the bearing cover,
- pulling out of the torque arm cover (19),
- placing a wheel stopper device (27, 27a, 27b) for axially arresting of a planet wheel (21) of a gearbox (7),
- pushing in the torque arm cover (19),
- assembling the bearing cover and
- removing all stopper plates (25, 28).

5. The method for repairing a gearbox of a wind turbine according one of the claims 1 to 4 comprising step of: subsequently arresting movement of rotor side bearing (22) for preventing damage of rotor side bearing (22) when moving the torque arm cover (19) toward rotor side bearing (22).

6. A wheel stopper device for axially arresting of a planet wheel of a gearbox and for using in a method according to claim 1 to 5, wherein the wheel stop-per device (27, 27a, 27b) having a mounting section (29) for mounting the wheel stopper device (27, 27a, 27b) to a ring gear (20) and a contact section (30) for avoiding axial movement of a planet wheel (21) and wherein the wheel stopper device (27, 27a, 27b) is ring shaped.

7. The wheel stopper device according to claim 6, wherein the contact section (30) dimensioned to cover teeth area of planet wheel (21).

8. The wheel stopper device according to claim 6 or 7, wherein the contact section (30a) dimensioned to cover teeth area and body area of planet wheel (21).

9. The wheel stopper device according to claim 8, wherein contact section () dimensioned to cover teeth area and body area of planet wheel (21) and in end region of contact section (30) is arranged an additional anti-friction ring (32) for reducing friction between wheel stopper device (27b) and planet wheel (21).

10. The wheel stopper device according to claim 9, wherein additional anti-friction ring (32) made of polytetrafluoroethylene (PTFE) or ceramic.

11. The wheel stopper device according to one of the claim 6 to 10, wherein the wheel stopper device (27, 27a, 27b) is segmented device having at least two segments.

12. A wind turbine characterized by a gearbox (7) having a wheel stopper de-vice (27, 27a, 27b) according to one of the claims 6 to 11.