REPAIRING A GEAR PART IN A WIND TURBINE

Abstract

A method for repairing a gear part (1) in a wind turbine, in particular repairing damaged teeth of a toothed rim (2). A repair cavity (10) is formed by removing material, including one or more damaged teeth, from the gear part (1) by drilling one or more holes through the gear part (1) along a direction which is substantially parallel to an axis of circular symmetry of the gear part (1). A repair segment (15) comprising one or more replacement gear teeth (16), and having a geometry which matches a geometry of the repair cavity (10), is arranged in the repair cavity (10), and attached to the gear part (1) by introducing one or more fasteners (17) into fastener openings (11, 13, 14) formed in the gear part (1).

Claims

1. A method for repairing a gear part in a wind turbine, the gear part comprising a toothed rim, and the gear part defining an axis of circular symmetry, the method comprising the steps of: removing material from the gear part, including one or more damaged teeth of the toothed rim, by drilling one or more holes through the gear part along a direction which is substantially parallel to the axis of circular symmetry, thereby forming a repair cavity in the gear part, providing at least one fastener opening in the gear part by drilling one or more holes and/or one or more recesses in the gear part, providing a repair segment having a geometry which matches a geometry of the repair cavity, the repair segment comprising one or more replacement gear teeth, arranging the repair segment in the repair cavity, and attaching the repair segment to the gear part by introducing one or more fasteners into the fastener opening(s).

2. The method according to claim 1, wherein the step of removing material from the gear part comprises drilling two or more holes through the gear part along a direction which is substantially parallel to the axis of circular symmetry, the two or more holes being arranged in abutment with each other or with an overlap, the two or more holes thereby forming a single repair cavity in the gear part.

3. The method according to claim 1, wherein the step of providing at least one fastener opening in the gear part comprises drilling one or more holes and/or one or more recesses in the gear part along a direction which is substantially parallel to the axis of circular symmetry.

4. The method according to claim 3, wherein the step of providing at least one fastener opening in the gear part comprises drilling one or more recesses in the gear part, said one or more recesses forming part of the repair cavity.

5. The method according to claim 3, wherein the step of providing at least one fastener opening in the gear part comprises providing a fastener opening having a first diameter and a recess having a second diameter, the second diameter being larger than the first diameter, the fastener opening and the recess being provided in a single drilling step, and the single drilling step being stopped when the recess has a predefined depth.

6. The method according to claim 1, further comprising the steps of: providing a jig comprising one or more guiding apertures, mounting the jig on the gear part in a region containing damaged gear teeth of the toothed rim, while aligning the jig with respect to undamaged gear teeth of the toothed rim, performing the steps of removing material from the gear part and providing at least one fastener opening in the gear part by drilling through the guiding aperture(s) of the jig, and removing the jig from the gear part after the steps of removing material from the gear part and providing at least one fastener opening in the gear part have been performed.

7. The method according to claim 1, further comprising the step of removing sharp edges from an inner surface of the repair cavity, by means of grinding or polishing, after the step of removing material from the gear part and prior to the step of arranging the repair segment in the repair cavity.

8. The method according to claim 1, wherein the step of removing material from the gear part is performed using an annular cutter drill bit.

9. The method according to claim 1, wherein the gear part forms part of a yaw system of a wind turbine.

10. The method according to claim 1, wherein the gear part forms part of a pitch system of a wind turbine.

11. A repaired gear part for a wind turbine, the gear part comprising: a toothed rim, a repair cavity formed in the gear part, said repair cavity defining at least one rounded contour formed by a drill bit, and a repair segment mounted in the repair cavity and attached to the gear part by means of one or more fasteners, the repair segment having a shape and a size which matches the at least one rounded contour of the repair cavity, and the repair segment comprising one or more replacement gear teeth.

12. The repaired gear part according to claim 11, wherein the repair cavity defines two or more rounded contours, each formed by a drill bit, the two or more rounded contours being arranged in abutment with each other or with an overlap.

13. The repaired gear part according to claim 11, wherein the at least one rounded contour(s) form(s) at least 50% of a surface of the repair cavity.

14. The repaired gear part according to claim 11, wherein the repaired gear part has been repaired by means of a method according to any of claims 1-10.

15. The repaired gear part according to claim 11, wherein the repaired gear part forms part of a yaw system of a wind turbine.

16. The repaired gear part according to claim 11, wherein the repaired gear part forms part of a pitch system of a wind turbine.

17. A jig for use in repairing a gear part in a wind turbine, the jig comprising: means for aligning the jig with gear teeth of a gear part to be repaired, at least one guiding aperture arranged for guiding a drill, and means for mounting the jig on a gear part to be repaired in a position where the guiding aperture(s) is/are arranged in a region comprising one or more damaged teeth of the gear part.

18. The jig according to claim 17, wherein the jig comprises at least two guiding apertures, the at least two guiding apertures being arranged in abutment with each other or with an overlap.

19. The jig according to claim 17, wherein the means for aligning the jig comprises a toothed rim arranged to be aligned with a toothed rim of a gear part, and wherein the means for mounting the jig on a gear part to be repaired is arranged to mount the jig in a position where the toothed rim of the jig is aligned with the toothed rim of the gear part.

20. The jig according to claim 17, wherein the at least one guiding aperture defines at least one rounded contour.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0073] The invention will now be described in further detail with reference to the accompanying drawings in which

[0074] FIGS. 1-4 illustrate various steps performed during repair of a gear part using a method according to an embodiment of the invention,

[0075] FIG. 5 is a perspective view of a repaired gear part according to an embodiment of the invention,

[0076] FIG. 6 is a top view of the repaired gear part of FIG. 5, and

[0077] FIGS. 7-9 are perspective views of a repair segment for use when performing a method according to an embodiment of the invention, seen from various angles.

DETAILED DESCRIPTION OF THE DRAWINGS

[0078] FIGS. 1-4 illustrate various steps performed during repair of a gear part 1 using a method according to an embodiment of the invention.

[0079] FIG. 1 is a perspective view of a part of a gear part 1, in the form of a yaw ring. The gear part 1 comprises a toothed rim 2 comprising a plurality of gear teeth. Some of the gear teeth have been damaged, and in the gear part 1 of FIG. 1 these damaged teeth have been removed in the manner described below.

[0080] In order to remove the damaged teeth, a jig 3 is mounted on the gear part 1 by means of a set of clamps 4. When mounted on the gear part 1, the jig 3 is aligned with respect to the teeth of the toothed rim 2 by positioning each of two aligning members 5 arranged on the jig 3 between two teeth of the toothed rim 2. The jig 3 is further provided with a set of teeth 6 which match the teeth of the toothed rim 2. Thereby it can be visually inspected that the jig 3 is properly aligned with respect to the teeth of the toothed rim 2.

[0081] The jig 3 comprises a guiding aperture 7, defining a number of rounded contours. The guiding aperture 7 can be used for guiding drilling operations performed on the gear part 1, by drilling a number of holes in the gear part 1 through the guiding aperture 7, when the jig 3 is mounted on the gear part 1.

[0082] The jig 3 is further mounted on the gear part 1 in a position where the guiding aperture 7 is arranged adjacent to a region comprising the damaged teeth. Thereby the damaged teeth can be removed from the gear part 1 by drilling through the guiding aperture 7.

[0083] In FIG. 1 drilling equipment 8 and a drill bit 9 to be mounted on the drilling equipment 8 are shown. Once the jig 3 has been mounted on the gear part 1, five holes are drilled in the gear part 1, using the drilling equipment 8. Initially, three through-going holes are drilled in the gear part 1 by means of an annular cutter drill bit, through the part of the guiding aperture 7 which is closest to the toothed rim 2. Thereby the damaged teeth are removed from the gear part 1. The drilling is performed along a direction which is substantially parallel to an axis of circular symmetry of the gear part 1. The through-going holes may be drilled one at a time, and when one hole has been drilled, the hole may be cleaned with respect to the resulting drilling core and dust-like drilling waste. This ensures that the next hole can be drilled with great accuracy.

[0084] Next, two fastener openings are drilled in the gear part 1 by means of a step spade drill bit, through the part of the guiding aperture 7 which is furthest away from the toothed rim 2.

[0085] Each of the fastener openings comprises a recess and an opening arranged to receive a fastener. The drilling is performed along a direction which is substantially parallel to the axis of circular symmetry of the gear part 1.

[0086] As a result of the drilling operations described above, a repair cavity 10 comprising a number of rounded contours, corresponding to the rounded contours of the guiding aperture 7 of the jig 3, is provided. Two additional fastener openings 11 have been drilled along a direction which is substantially perpendicular to the axis of circular symmetry of the gear part 1.

[0087] In FIG. 1 the various parts described above are shown in an exploded manner, for instance the jig 3 is not mounted on the gear part 1. Furthermore, the gear part 1 is shown after the drilling operations have been performed, i.e. after the damaged teeth have been removed and the repair cavity 10 has been formed.

[0088] FIG. 2 is a perspective view of the gear part 1 of FIG. 1, with the jig 3 mounted on the gear part 1 in the manner described above. It can be seen that the jig 3 is aligned with respect to the teeth of the toothed rim 2, due to the aligning members 5, since the teeth 6 of the jig 3 are aligned with teeth of the toothed rim 2.

[0089] FIG. 3 is a perspective view of the gear part 1 of FIGS. 1 and 2. However, in FIG. 3 the jig 3 has been removed from the gear part 1, after the drilling has been performed. In FIG. 3 it can be easily seen that the repair cavity 10 comprises three rounded contours 12 originating from the three holes drilled by means of the annular cutter drill bit. The repair cavity 10 further comprises two recesses 13 and two fastener openings 14 originating from the two holes drilled by means of the step spade drill bit.

[0090] FIG. 4 is a perspective view of the gear part 1 of FIGS. 1-3. FIG. 4 further shows a repair segment 15 to be mounted in the repair cavity 10. The repair segment 15 has a geometry, i.e. a size and a shape, which matches the geometry of the repair cavity 10. Furthermore, the repair segment 15 comprises three replacement teeth 16. Four fasteners 17 for attaching the repair segment 15 to the gear part 1 are shown.

[0091] FIG. 5 is a perspective view of the gear part 1 of FIGS. 1-4, with the repair segment 15 mounted in the repair cavity. The fasteners 17 have been introduced into the fastener openings, thereby attaching the repair segment 15 to the gear part 1.

[0092] It can be seen that the repair segment 15 fits precisely into the repair cavity, and that it is mounted flush with an upper side of the gear part 1. Furthermore, the replacement teeth 16 of the repair segment 15 match the original size and shape of the damaged teeth, and therefore the replacement teeth 16 replace the damaged teeth, and the toothed rim 2 is thereby restored.

[0093] Thus, the gear part 1 of FIG. 5 is a repaired gear part 1.

[0094] FIG. 6 is a top view of the repaired gear part 1 of FIG. 5.

[0095] FIGS. 7-9 are perspective views of a repair segment 15 for use when performing a method according to an embodiment of the invention. The repair segment 15 has a geometry which matches the geometry of the repair cavity of the gear part of FIGS. 1-6. Accordingly, the repair segment 15 comprises three rounded contours 18 which match the rounded contours of the repair cavity, which were provided when the three through-going holes were drilled. Furthermore, two protruding portions 19 are provided. The protruding portions 19 fit into the recesses of the repair cavity, which were provided when the fastener openings were drilled.

[0096] The repair segment 15 further comprises three replacement teeth 16 being adapted to replace damaged teeth of a toothed rim, in the manner described above.

[0097] The protruding portions 19 are provided with openings 20 arranged to receive fasteners in order to attach the repair segment 15 to the gear part. Additional openings 21 are provided for receiving fasteners to engage with the additional fastener openings provided in the gear part.