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EP-3721084-B1 - METHOD FOR REPAIRING A GEAR AND PROCESSING MACHINE FOR CARRYING OUT THE METHOD

EP3721084B1EP 3721084 B1EP3721084 B1EP 3721084B1EP-3721084-B1

Inventors

  • LØVLUND TOFT, Hans

Dates

Publication Date
20260506
Application Date
20181115

Claims (12)

  1. A segment (12, 12', 12", 12"') for repairing a gear (2) having a number of damaged teeth (4, 4', 4"), the gear (2) comprising a pocket structure (28, 28', 28", 28"') resulted milling at least one damaged tooth (4, 4', 4"), the segment (12, 12', 12", 12"') having a geometry that fits the geometry of the pocket structure (28, 28', 28", 28"'), wherein the segment (12, 12', 12", 12‴) is configured to be radially inserted into the pocket structure (28, 28', 28", 28‴) and to attach radially extending attachment structures (60, 60') through at least a portion (18, 18') of the segment (12, 12', 12", 12"') and further into at least a portion (32, 32') of the underlying structure (64) of the gear (2), characterised in that : a) the segment (12, 12', 12", 12"') comprises an end tooth (4') having a support surface (66) configured to bear radially against a remaining structure (14') next to the pocket structure (28), and b) the end tooth (4') has an end wall (40) configured to bear tangentially against a contact wall (68) of the pocket structure (28), wherein each end portion of the segment (12) is formed as a recess having that end wall (40) angled relative to a lower surface (36) of the segment (12, 12', 12", 12‴), wherein the angle (α) between the end wall (40) and an adjacent portion of the lower surface (36) is in the range 70-110°, preferably between 80-100°.
  2. A segment (12, 12', 12", 12"') according to claim 1, characterised in that the segment (12, 12', 12", 12‴) comprises the lower surface (36) and a support structure (38) extending between the lower surface (36) and the bottom portion of the teeth (4, 4'), wherein the support structure (38) has a concave bottom surface (30).
  3. A repaired gear (2) comprising several segments (12, 12', 12", 12"') according to one of the preceding claims, wherein the segments (12, 12', 12", 12"') are fixed to the gear (2) in extension of each other, wherein adjacent segments (12, 12', 12", 12‴) are only separated by the remaining structures (14, 14', 14").
  4. A method for repairing a gear (2) by inserting a segment (12, 12', 12", 12‴) according to claim 1 or 2, the gear (2) having a number of damaged teeth (4, 4', 4"), characterised in that the method comprising: a) removing material from the gear (2) by milling hereby providing a pocket structure (28, 28', 28", 28‴), wherein said material includes the at least one damaged tooth (4, 4', 4"), wherein the pocket structure (28, 28', 28", 28‴) comprises a bottom surface (30) extending between two opposing end structures (34, 34'); b) providing a recess (42) at at least one end of the segments (12, 12', 12", 12‴) c) providing said segment (12, 12', 12", 12‴) to be inserted into the pocket structure (28, 28', 28", 28"'), wherein the segment (12, 12', 12", 12‴) has a geometry that fits the geometry of the pocket structure (28, 28', 28", 28"'), d) drilling a number of radially extending holes (32, 32') in the underlying structure (64); e) radially inserted into the pocket structure (28, 28', 28", 28‴) and attaching radially extending attachment structures (60, 60') through at least a portion (18, 18') of the segment (12, 12', 12", 12"') and further into at least a portion (32, 32') of the underlying structure (64) of the gear (2); f) providing an end tooth (4'), wherein the end tooth (4') is provided with a through hole (18) and has an end wall (40) configured to bear against the contact wall (68) of the pocket structure (28), and further the end tooth (4') has a support surface (66) configured to bear against the remaining structure (14') next to the pocket structure (28).
  5. A method according to claim 4, characterised in that the method comprises the step of attaching one or more bolts (60, 60') through at least a portion of the segment (12, 12', 12", 12‴) and further into at least a portion (32, 32') of the underlying structure (64) of the gear (2), wherein the bolts (60, 60') are angled (α) relative to the radial direction of the gear (2).
  6. A method according to one of the preceding claims 4-5, characterised in that the remaining structure (14, 14', 14", 14‴) extends between the flanks (26) of two adjacent teeth (4, 4').
  7. A processing machine (50) for repairing a gear (2) having a number of damaged teeth (4, 4', 4"), wherein said processing machine (50) is configured to perform the method according to claims 4-6 and comprises: - a number of gear attachments (46, 46') configured to be detachably attached to the gear (2) and - a moveably arranged carrier (56) having a spindle unit (58) configured to carry out a milling process hereby removing one or more damaged teeth (4, 4', 4") and providing a pocket structure (28, 28', 28", 28"') configured to receive a toothed segment (12, 12', 12", 12‴), characterised in that the processing machine (50) is configured to carry out the milling process radially from outside the gear (2).
  8. A processing machine (50) according to claim 7, characterised in that the processing machine (50) comprises: - one or more sensors configured to detect one or more parameters indicative of the geometry of the structure being processed by the spindle unit (58) and - a controller configured to control the spindle unit (58) on the basis of said one or more parameters.
  9. A processing machine (50) according to claim 8, characterised in that the controller is a Computer Numerical Control (CNC) controller.
  10. A processing machine (50) according to claim 8 or 9, characterised in that the processing machine (50) comprises: - one or more guides (48, 48') and - a slide (52) comprising a carrier (56) comprising said spindle unit (58), wherein said slide (52) is moveably mounted on the one or more guides (48, 48');
  11. A processing machine (50) according to one of the claims 8-10, characterised in that the spindle unit (58) is moveably arranged in the processing machine (50) in such a manner that the spindle unit (58) can be moved radially along the radial axis (Z') and/or the axial axis (Y') and/or the tangential axis (X') of the processing machine (50).
  12. A processing machine (50) according to one of the claims 7-11, characterised in that the processing machine (50) comprises a drilling unit configured to drill holes (32, 32') in the gear (2).

Description

Field of invention The present invention relates to a segment for repairing a gear having a number of damaged teeth and a method for repairing a gear having a number of damaged teeth. The present invention also relates to a processing machine for carrying out the method including providing pocket structures in a gear. The invention is in particular applicable for repairing a yaw ring in a wind turbine. Prior art The prior art discloses several ways of repairing damaged teeth of gears. US2009220343A1 discloses a method for repairing a hub pitch gear assembly. The method includes providing a ring assembly for adjusting a pitch angle of a wind turbine blade. The ring has a plurality of gear teeth. When applying the method, a segment comprising at least one gear tooth of the ring assembly is removed. Hereby, a repair cavity is formed. A repair segment configured to match the repair cavity is provided and the repair segment is directed into the repair cavity and fastened in position. A repaired pitch gear assembly and wind turbine are also disclosed. WO2016062315A2 discloses a method for repairing a gear part in a wind turbine, in particular repairing damaged teeth of a toothed rim. A repair cavity is formed by removing material, including one or more damaged teeth, from the gear part by drilling one or more holes through the gear part along a direction which is substantially parallel to an axis of circular symmetry of the gear part. A repair segment comprising one or more replacement gear teeth, and having a geometry which matches a geometry of the repair cavity, is arranged in the repair cavity, and attached to the gear part by introducing one or more fasteners into fastener openings formed in the gear part. US20140112789A1 discloses a roller bearing comprising a plurality of gear segments removably attached to an outer ring of the roller bearing. Accordingly, when one or more teeth are damaged, the respective segment(s) can be replaced with a new one. When repairing a yaw gear, however, there is no space to axially attach the repair segments. Moreover, it is not possible to apply this method to replace adjacent repair segments because attachment of repair segments requires a fixed support (which is not present), to which the end structure of the repair segment is fixed. Thus, there is a need for a segment, method and a machine that can reduce or even eliminate the above-mentioned disadvantages of the prior art. It is an object of the present invention to provide a segment, method and a machine that can be used to repair a yaw gear. It is also an object to be provide a segment, method to replace teeth of non-segmented gears. It is also an object of the invention to repair and replace adjacent repair segments. Summary of the invention The object of the present invention can be achieved by a segment as defined in claim 1, a repaired gear as defined in claim 3, a method as defined in claim 4 and by a processing machine as defined in claim 7. Preferred embodiments are defined in the dependent subclaims, explained in the following description and illustrated in the accompanying drawings. The segment according to the invention is a segment as defined in claim 1. Hereby, it is possible to provide a segment that can be used to repair a yaw gear even though there is limited space available for carrying out the reparation. The method according to the invention is defined in claim 4, The method makes it possible to replace adjacent repair segments and thus all teeth in along a selection or the entire circumference of the gear can be repaired by using the method according to the invention. In principle, the method according to the invention can be used for repairing all types of gears having a number of damaged teeth. The method makes it possible to replace teeth of non-segmented gears. The method may in particular be used for repairing a yaw ring (gear) in a wind turbine. The method comprises the step of removing material from the gear hereby providing a pocket structure, wherein said material includes at least one damaged tooth. This step is preferably carried out by applying a processing machine that is capable of being detachably attached to the gear and to process the gear radially from outside. Hereby, the method can be used in a wind turbine for repairing a yaw ring (gear). The method comprises the step of providing a segment to be inserted into the pocket structure, wherein the segment has a geometry that fits the geometry of the pocket structure. The segment will be premanufactured. When the gear to be repaired is known, it is possible to provide a segment that has a geometry that corresponds to the gear. By providing a segment having a geometry that fits the geometry of the pocket structure, the geometric fit will prevent displacement of the segment tangentially and axially. The pocket structure may have any suitable geometry. In one embodiment, the pocket structure comprises one or more portions constituting on