A WIND TURBINE COMPRISING A TORQUE TRANSMITTING COUPLING

Abstract

A wind turbine (101) comprising a torque transmitting coupling (1) between a first rotatable part (2, 3) and a second rotatable part (2, 3) of the wind turbine (101), e.g. in the form of a hub (2) and a shaft (3), is disclosed. The torque transmitting coupling (1) comprises a form- fitted coupling and a compression means (5, 8, 9, 12, 13). The form-fitted coupling defines a plurality of drive flanks formed on the first rotatable part (2, 3) and a plurality of driven flanks formed on the second rotatable part (2, 3). The compression means (5, 8, 9, 12, 13) is arranged on an internal or external perimeter of the form-fitted coupling, and the compression means (5, 8, 9, 12, 13) provides a frictional coupling between the first rotatable part (2, 3) and the second rotatable part (2, 3). The torque transmitting coupling (1) is capable of locking up to six degrees of freedom between the first rotatable part (2, 3) and the second rotatable part (2, 3), while allowing the first rotatable part (2, 3) and the second rotatable part (2, 3) to be easily dissembled.

Claims

1. A wind turbine comprising a torque transmitting coupling between a first rotatable part and a second rotatable part of the wind turbine, the first rotatable part and the second rotatable part being arranged concentrically with respect to each other, the torque transmitting coupling comprising: form-fitted coupling defining a plurality of drive flanks formed on the first rotatable part and a plurality of driven flanks formed on the second rotatable part, the drive flanks being arranged in torque transmitting engagement with the driven flanks, and the drive flanks and the driven flanks extending substantially along a direction defined by an axis of rotation of the first and second rotatable parts, and a compression means arranged on an internal or external perimeter of the form-fitted coupling, the compression means providing a frictional coupling between the first rotatable part and the second rotatable part.

2. The wind turbine according to claim 1, wherein the form-fitted coupling defines a plurality of lands formed on the first rotatable part and a plurality of opposing lands formed on the second rotatable part, and wherein the compression means is arranged to remove a clearance between the lands and the opposing lands, thereby providing the frictional coupling between the lands and the opposing lands.

3. The wind turbine according to claim 2, wherein the lands are in the form of top lands or in the form of bottom lands.

4. The wind turbine according to claim 1, wherein the form-fitted coupling comprises a first set of teeth formed on the first rotatable part and a second set of teeth formed on the second rotatable part, the first set of teeth defining the drive flanks and the second set of teeth defining the driven flanks.

5. The wind turbine according to claim 1, a wherein the form-fitted coupling is or comprises a spline.

6. The wind turbine according to claim 1, wherein the drive flanks form an integral part of the first rotatable part and/or the driven flanks form an integral part of the second rotatable part.

7. The wind turbine according to claim 1, wherein the compression means comprises at least one conical surface, and wherein the compression means is arranged to provide compression by dislocating at least one part having a conical surface formed thereon.

8. The wind turbine according to claim 7, wherein at least one conical surface forms an integral part of the first rotatable part and/or at least one conical surface forms an integral part of the second rotatable part.

9. The wind turbine according to claim 1, wherein the first rotatable part or the second rotatable part is a hub, and the second rotatable part or the first rotatable part is a shaft.

10. The wind turbine according to claim 1, wherein the frictional coupling is resolvable.

11. The wind turbine according to claim 1, wherein the drive flanks and the driven flanks are arranged on mating conical parts of the first rotatable part and the second rotatable part.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The invention will now be described in further detail with reference to the accompanying drawings in which

[0041] FIG. 1 is a perspective view of a torque transmitting coupling for use in a wind turbine according to a first embodiment of the invention,

[0042] FIG. 2 is a perspective view of a torque transmitting coupling for use in a wind turbine according to a second embodiment of the invention,

[0043] FIG. 3 is a perspective view of a torque transmitting coupling for use in a wind turbine according to a third embodiment of the invention,

[0044] FIG. 4 is a perspective view of a torque transmitting coupling for use in a wind turbine according to a fourth embodiment of the invention,

[0045] FIGS. 5 and 6 illustrate an exemplary wind turbine according to an embodiment of the invention, and

[0046] FIG. 7 is a perspective view of a part of a rotatable part comprising a set of teeth forming part of a torque transmitting coupling for use in a wind turbine according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0047] FIG. 1 is a perspective view of a torque transmitting coupling 1 for use in a wind turbine according to a first embodiment of the invention. Parts of the torque transmitting coupling 1 have been broken away in order to reveal interior parts of the torque transmitting coupling 1.

[0048] The torque transmitting coupling 1 comprises a first rotatable part in the form of a hub 2 and a second rotatable part in the form of a shaft 3. The hub 2 and the shaft 3 are arranged concentrically with respect to each other in such a manner that a part of the hub 2 is arranged along an exterior part of the shaft 3. Thereby an overlapping region between the hub 2 and the shaft 3 is defined, and the hub 2 and the shaft 3 are arranged to rotate about a common axis of rotation. In the overlapping region, the hub 2 is provided with a set of teeth (not visible) at an inner perimeter facing the shaft 3. Furthermore, the shaft 3 is provided with a set of teeth 4 at an outer perimeter facing the hub 2. Thereby the teeth formed on the hub 2 and the teeth 4 formed on the shaft 3 are arranged in torque transmitting engagement, thereby forming a form-fitted coupling between the hub 2 and the shaft 3.

[0049] The torque transmitting coupling 1 further comprises a compression means in the form of a clamping ring 5 arranged on an external perimeter of the form-fitted coupling, i.e. in a position corresponding to the overlapping region of the hub 2 and the shaft 3. The clamping ring 5 is provided with a conical inner surface 6 which is arranged in contact with a conical outer surface 7 formed on the hub 2. The clamping ring 5 can be mounted onto the hub 2 by displacing it along an axial direction defined by the common axis of rotation of the hub 2 and the shaft 3. In the embodiment shown in FIG. 1, the displacing motion is performed by means of bolts. However, the displacing motion may, alternatively, be performed by means of hydraulics or tools, or in other suitable ways.

[0050] As the clamping ring 5 is displaced axially as described above, the conical surfaces 6, 7 cause the clamping ring 5 to contract the hub 2, thereby pressing the hub 2 towards the shaft 3 in the overlapping region, i.e. in the region where the form-fitted coupling between the hub 2 and the shaft 3 is formed. Thereby a compression stress is created which bridges any geometric clearance between the teeth formed on the hub 2 and the teeth 4 formed on the shaft 3. As a consequence, the top lands of the teeth 4 formed on the shaft 3 make contact in the root of the teeth formed on the hub 2, and the top lands will be allowed to transfer forces by means of friction. Accordingly, the clamping ring 5 provides a frictional coupling between the hub 2 and the shaft 3.

[0051] The frictional coupling provided by the clamping ring 5, as described above, ensures that any backlash of the form-fitted coupling is essentially eliminated, and essentially locks the degrees of freedom which are not locked by the form-fitted coupling. Furthermore, since the frictional coupling is provided by the clamping ring 5 being slided onto the hub 2, the frictional coupling can easily be dissembled without destroying any parts of the torque transmitting coupling 1.

[0052] FIG. 2 is a perspective view of a torque transmitting coupling 1 for use in a wind turbine according to a second embodiment of the invention. Parts of the torque transmitting coupling 1 have been broken away in order to reveal interior parts of the torque transmitting coupling 1.

[0053] The torque transmitting coupling 1 of FIG. 2 is similar to the torque transmitting coupling 1 of FIG. 1 in the sense that it comprises a hub 2 and a shaft 3 arranged concentrically with respect to each other, thereby forming an overlapping region in which a set of teeth (not shown) formed on the hub 2 and a set of teeth 4 formed on the shaft 3 are arranged in torque transmitting engagement, thereby forming a form-fitted coupling between the hub 2 and the shaft 3.

[0054] The hub 2 of the torque transmitting coupling 1 of FIG. 2 has a relatively large diameter in the overlapping region, and therefore an external clamping ring, as illustrated in FIG. 1, is not suitable for providing the frictional coupling. But it provides a large moment of resistance for maintaining a contact pressure. Instead the torque transmitting coupling 1 of FIG. 2 comprises a compression means in the form of a double conical inner support ring 8 and two outer rings 9, each being provided with an inner conical surface 10 arranged in contact with an outer conical surface 11 of the double conical inner support ring 8. The compression means is arranged in a position corresponding to the position of the overlapping region defined by the hub 2 and the shaft 3, i.e. in the region of the form-fitted coupling between the hub 2 and the shaft 3.

[0055] The outer rings 9 are arranged to be displaced axially, in opposite directions. Similarly to the embodiment illustrated in FIG. 1, the outer rings 9 thereby push the shaft 3 outwards and towards the hub 2, and bridging any geometrical clearance between the teeth formed on the hub 2 and the teeth 4 formed on the shaft 3. Accordingly, a friction coupling between the hub 2 and the shaft 3 is formed by means of the compression means 8, 9, and the advantages described above with reference to FIG. 1 are obtained.

[0056] FIG. 3 is a perspective view of a torque transmitting coupling 1 for use in a wind turbine according to a third embodiment of the invention. Parts of the torque transmitting coupling 1 have been broken away in order to reveal interior parts of the torque transmitting coupling 1.

[0057] The torque transmitting coupling 1 of FIG. 3 is very similar to the torque transmitting coupling 1 of FIG. 2 in that it also comprises a compression means arranged on an internal perimeter of the overlapping region, and thereby of the form-fitted coupling formed between the hub 2 and the shaft 3. In the torque transmitting coupling 1 of FIG. 3 the compression means is in the form of an insert ring 12 arranged along an inner perimeter of the hub 2 and a clamping device 13 arranged along an inner perimeter of the insert ring 12.

[0058] The insert ring 12 is provided with an inner conical surface 14, and the clamping device 13 is provided with an outer conical surface 15, the conical surfaces 14, 15 being arranged in contact with each other. Accordingly, a frictional coupling can be provided between the hub 2 and the shaft 3 by displacing the clamping device 13 axially, similarly to the situation described above with reference to FIG. 2.

[0059] The clamping device 13 is provided with a web 16 with a high moment of resistance. The web 16 prevents the shaft 3 from contraction when the clamping device 13 is displaced axially in order to provide the frictional coupling between the hub 2 and the shaft 3.

[0060] It should be noted that even though the insert ring 12 is shown as a separate part in FIG. 3, it could also be envisaged that the inner conical surface 14 provided by the insert ring 12 could be formed directly on the inner perimeter of the shaft 3.

[0061] FIG. 4 is a perspective view of a torque transmitting coupling 1 for use in a wind turbine according to a fourth embodiment of the invention. Parts of the torque transmitting coupling 1 have been broken away in order to reveal interior parts of the torque transmitting coupling 1.

[0062] The torque transmitting coupling 1 of FIG. 4 is very similar to the torque transmitting coupling 1 of FIG. 1, and it will therefore not be described in detail here. In the torque transmitting coupling 1 of FIG. 4 a pilot diameter 17 is provided in the overlapping region at a position adjacent to the teeth formed on the hub 2 and the teeth 4 formed on the shaft 3. This is particularly advantageous in the case that transverse forces and moments acting on the hub 2 and the shaft 3 are large compared to the torque being transferred between the hub 2 and the shaft 3. The friction coupling provided by the clamping ring 5 acts on the pilot diameter 17 as well as on the form-fitted coupling defined by the engaged teeth 4.

[0063] Reference will now be made to FIGS. 5 and 6 to illustrate an exemplary wind turbine 101 for implementation of the torque transmitting coupling as described herein. FIG. 5 illustrates a wind turbine 101, comprising a tower 102 and a wind turbine nacelle 103 positioned on top of the tower 102. The wind turbine rotor 104, comprising three wind turbine blades 105, is connected to the nacelle 103 through the low speed shaft 6 which extends out of the nacelle 103 front.

[0064] FIG. 6 illustrates an embodiment of a wind turbine nacelle 103, as seen from the side. The drive train in a traditional wind turbine 101 known in the art usually comprises a rotor 104 connected to a gearbox 107 by means of a low speed shaft 106. In this embodiment the rotor 104 comprise only two blades 105 connected to the low speed shaft 106 by means of a teeter mechanism 108, but in another embodiment the rotor 104 could comprise another number of blades 105, such as three blades 105, which is the most common number of blades 105 on modern wind turbines 101. In another embodiment the rotor 104 could also be connected directly to the gearbox 107.

[0065] The gearbox 107 is then connected to the generator 109 by means of a high speed shaft 110.

[0066] Because of the limited space in the nacelle 103 and in order to minimize the weight of the nacelle 103 the preferred gearbox 107 type in most modern wind turbines 101 is an epicyclical gearbox, but other gearbox types are also feasible, such as one or more spur gearboxes, worm gearboxes, helical gearboxes or a combination of different transmission and gearbox 107 types.

[0067] FIG. 7 is a perspective view of a part of a rotatable part 3 comprising a set of teeth 4, two of which are shown. The teeth 4 are formed on an outer surface of the rotatable part 3, and form part of a torque transmitting coupling for use in a wind turbine according to an embodiment of the invention. The teeth 4 are adapted to engage mating teeth formed on an inner surface of another rotatable part, e.g. as described above with reference to any of FIGS. 1-4.

[0068] Each tooth 4 defines a drive flank 18 arranged to engage a driven flank of a tooth of another rotatable part, thereby forming a form-fitted coupling. Furthermore, each tooth 4 defines a top land 19 on a part of the tooth 4 which faces the other rotatable part. Bottom lands 20 are defined between the teeth 4. The surfaces of the top lands 19 follow an addendum circle of the teeth 4, and the surfaces of the bottom lands 20 follow a dedendum circle.

[0069] When the rotatable part 3 is arranged adjacent to another rotatable part, essentially in the manner described above with reference to any of FIGS. 1-4, the top lands 19 will be positioned opposite bottom lands formed between the teeth of the other rotatable part, and the bottom lands 20 will be positioned opposite top lands formed on the teeth of the other rotatable part, with a clearance between oppositely positioned lands 19, 20. The clearance 21 between the bottom lands 20 and the top lands of the other rotatable part is indicated in FIG. 7.

[0070] When compression means is subsequently arranged on an internal or external perimeter of the form-fitted coupling, the oppositely positioned lands 19, 20 are pushed towards each other. For instance, the bottom lands 20 of the rotatable part 3 and the oppositely positioned top lands of the other rotatable part may be pushed towards each other until the clearance 21 between the bottom lands 20 and the top lands is removed. Thereby a frictional coupling is provided between the bottom lands 20 and the top lands of the other rotatable part.

[0071] As an alternative, the top lands 19 of the rotatable part 3 and the bottom lands of the other rotatable part may be pushed towards each other until the clearance between the top lands 19 and the bottom lands is removed, thereby providing a frictional coupling between the top lands 19 and the bottom lands of the other rotatable part.

[0072] As another alternative, the clearance between the top lands 19 of the rotatable part 3 and the bottom lands of the other rotatable part, as well as the clearance 21 between the bottom lands 20 and the top lands of the other rotatable part may be removed.

[0073] In any event, the gap between the rotatable part 3 and the other rotatable part which needs to be bridged by the compression means, in order to provide the frictional coupling, is relatively small. Furthermore, since the lands 19, 20 form part of a cylindrical shape, the tolerance requirements are not critical.

[0074] The invention has been exemplified above with reference to specific examples. However, it should be understood that the invention is not limited to the particular examples described above but may be designed and altered in a multitude of varieties within the scope of the invention as specified in the claims.