A WIND TURBINE WITH A ROTOR COMPRISING A HOLLOW KING PIN

Abstract

A wind turbine (11) comprising a tower structure (12, 13) and two or more rotors (1). Each rotor (1) comprises a hollow king pin (2) and a hub (4) carrying one or more rotor blades (14). The hollow king pin (2) is formed in a single cylindrical piece, and is mounted on the tower structure (12, 13). The hub (4) is rotatably mounted on the hollow cylindrical king pin (2). A generator (6) is operationally coupled to the hub (4) in such a manner that rotational movements of the hub (4) are transferred to the generator (6). The tower structure comprises a main tower part (12) being anchored, at a lower part, to a foundation structure, and at least two arms (13), each arm (13) extending away from the main tower part (12) along a direction having a horizontal component. Each arm (13) carries at least one rotor (1).

Claims

1. A wind turbine comprising: a tower structure, the tower structure comprising: a main tower part being anchored, at a lower part, to a foundation structure, the main tower part extending along a substantially vertical direction, and at least two arms, each arm extending away from the main tower part along a direction having a horizontal component, two or more rotors, each rotor comprising: a hollow king pin formed in a single cylindrical piece, the hollow cylindrical king pin being mounted on the tower structure, a hub carrying one or more rotor blades, the hub being rotatably mounted on the hollow cylindrical king pin, and a generator being operationally coupled to the hub in such a manner that rotational movements of the hub are transferred to the generator wherein each arm of the tower structure carries at least one rotor.

2. The wind turbine according to claim 1, wherein the hollow cylindrical king pin of at least one rotor is mounted on a lower part of an arm of the tower structure.

3. The wind turbine according to claim 1, wherein the hollow cylindrical king pin of each of the rotors is mounted directly on an arm of the tower structure, and wherein the wind turbine further comprises a yawing mechanism arranged between the main tower part and a part of the tower structure comprising the arms.

4. The wind turbine according to claim 1, wherein the hollow cylindrical king pin extends behind the tower structure along a direction facing the wind.

5. The wind turbine according to claim 1, wherein the hollow cylindrical king pin has a substantially uniform wall thickness.

6. The wind turbine according to claim 1, wherein at least one of the rotors comprises a gear arrangement arranged to transfer rotational movements of the hub to rotational movements of a rotating shaft connected to the generator.

7. The wind turbine according to claim 6, wherein at least part of the rotating shaft is arranged inside the hollow cylindrical king pin.

8. The wind turbine according to claim 6, wherein the gear arrangement comprises a number of pulleys and a number of belts interconnecting the pulleys in order to transfer rotational movements between the pulleys, thereby transferring rotational movements from the hub to the rotating shaft.

9. The wind turbine according to claim 8, wherein the gear arrangement comprises: a primary pulley being rotationally decoupled from the hub, two or more planetary pulleys, each planetary pulley being mounted on the hub, thereby rotating along with the hub, and each planetary pulley being provided with a planetary shaft, each planetary pulley being arranged to perform rotational movements about its planetary shaft, and a centre pulley being connected to the rotating shaft, wherein at last one belt interconnects the primary pulley to each of the planetary shafts, and at least one belt interconnects each of the planetary pulleys to the centre pulley.

10. The wind turbine according to claim 6, wherein the gear arrangement is arranged in front of the hub along a direction facing the wind.

11. The wind turbine according to claim 6, wherein the gear arrangement is arranged behind the hollow cylindrical king pin along a direction facing the wind.

12. The wind turbine according to claim 1, wherein the generator is bolted onto an end of the hollow cylindrical king pin, via one or more threaded holes formed in a wall of the hollow cylindrical king pin, said one or more threaded holes extending substantially along an axial direction defined by the hollow cylindrical king pin.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The invention will now be described in further detail with reference to the accompanying drawings in which

[0062] FIG. 1 is a side view of a rotor for a wind turbine according to a first embodiment of the invention,

[0063] FIG. 2 is a side view of a rotor for a wind turbine according to a second embodiment of the invention,

[0064] FIG. 3 is a side view of a rotor for a wind turbine according to a third embodiment of the invention,

[0065] FIG. 4 is a front view of a wind turbine according to a fourth embodiment of the invention, and

[0066] FIGS. 5 and 6 illustrate a rotor for a wind turbine according to a fifth embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0067] FIG. 1 is a side view of a rotor 1 for a wind turbine according to a first embodiment of the invention. The rotor 1 comprises a hollow king pin 2 formed in a single cylindrical piece. The rotor 1 can be mounted on a part of a tower structure (not shown) of the wind turbine, via the hollow cylindrical king pin 2 and a mounting frame 3. Accordingly, the hollow cylindrical king pin 2 is not able to rotate with respect to the tower structure.

[0068] A hub 4 is mounted rotatably on the hollow cylindrical king pin 2, via a bearing arrangement 5. Accordingly, the hub 4 is able to perform rotational movements with respect to the hollow cylindrical king pin 2. The hub 4 carries a number of rotor blades (not shown), and when the wind acts on the rotor blades, the hub 4 is caused to rotate with respect to the hollow cylindrical king pin 2.

[0069] The rotational movements of the hub 4 are transferred to a generator 6, via a gear arrangement 7 and a rotating shaft 8, which extends through the hollow cylindrical king pin 2. Thereby electricity is generated, essentially as described above.

[0070] The gear arrangement 7 comprises a number of pulleys 9 and a number of belts 10 interconnecting the pulleys 9 in order to transfer rotational movements between the pulleys 9. Thus, the gear arrangement 7 is in the form of a belt drive.

[0071] The gear arrangement 7 is arranged in front of the hub 4, along a direction facing the wind, i.e. as seen in the direction of the incoming wind. Thereby the pulleys 9 and the belts 10 are readily accessible, e.g. for the purpose of performing maintenance on the gear arrangement 7. For instance, this allows the belts 10 of the gear arrangement 7 to be easily repaired or replaced, without having to dismantle the hub 4 or the generator 6.

[0072] The generator 6 is arranged behind the hollow cylindrical king pin 2 along the direction facing the wind. Accordingly, the generator 6 is arranged at an end of the hollow cylindrical king pin 2 which is opposite to an end where the hub 4 and the gear arrangement 7 are arranged. The generator 6 may be bolted directly onto the hollow cylindrical king pin 2, via threaded holes formed in the wall of the hollow cylindrical king pin 2, the holes extending in parallel to the axis of the cylinder defined by the hollow cylindrical king pin 2.

[0073] FIG. 2 is a side view of a rotor 1 for a wind turbine according to a second embodiment of the invention. The rotor 1 of FIG. 2 is very similar to the rotor 1 of FIG. 1, and it will therefore not be described in detail here.

[0074] In the rotor 1 of FIG. 2, the rotating shaft 8 does not extend through the hollow cylindrical king pin 2, but is instead arranged in parallel to and below the hollow cylindrical king pin 2. Furthermore, the gear arrangement 7 is arranged immediately behind the hub 4. The generator 6 is also arranged below the hollow cylindrical king pin 2. This provides a more compact rotor design than the design of the rotor 1 of FIG. 1.

[0075] The rotor 1 of FIG. 2 is very suitable for being mounted below a part of the tower structure, for instance on a lower side of an arm of the tower structure, e.g. suspended from a part of the tower structure, because the generator 6 and the rotating shaft 8 are arranged below the hollow cylindrical king pin 2. In this case the generator 6 and the rotating shaft 8 are arranged on an opposite side of the hollow cylindrical king pin 2 as compared to the mounting frame 3, and the generator 6 and the rotating shaft 8 are thereby not in the way when the mounting frame 3 is attached to the tower structure.

[0076] It should be noted that, as an alternative, the generator 6 could be arranged above the hollow cylindrical king pin 2, thereby allowing the rotor 1 to be mounted above a part of the tower structure, e.g. resting on a part of the tower structure.

[0077] FIG. 3 is a side view of a rotor 1 for a wind turbine according to a third embodiment of the invention. The rotor 1 of FIG. 3 is very similar to the rotors 1 of FIGS. 1 and 2, and it will therefore not be described in detail here.

[0078] In the rotor 1 of FIG. 3, the generator 6 and the rotating shaft 8 are arranged below the hollow cylindrical king pin 2, similar to the embodiment of FIG. 2, and thereby the rotor 1 is very suitable for being mounted below a part of the tower structure, e.g. suspended from a part of the tower structure. However, in the rotor 1 of FIG. 3, the gear arrangement 7 is arranged behind the hollow cylindrical king pin 2. Thereby the gear arrangement 7 is readily accessible, similarly to the situation described above with reference to FIG. 1.

[0079] As described above, the generator 6 and the rotating shaft 8 could, as an alternative, be arranged above the hollow cylindrical king pin 2, thereby allowing the rotor 1 to be mounted above a part of the tower structure, e.g. resting on a part of the tower structure.

[0080] FIG. 4 is a front view of a wind turbine 11 according to a fourth embodiment of the invention. The wind turbine comprises a tower structure with a main tower part 12 and four arms 13, each extending substantially horizontally away from the main tower part 12.

[0081] Each of the arms 13 carries a rotor 1, each rotor 1 comprising a hub 4 carrying three rotor blades 14. Accordingly, the wind turbine 11 is of a multirotor kind. The rotors 1 could, e.g., be of the kind illustrated in one of FIGS. 1-3.

[0082] The four arms 13 are arranged in such a manner that two of them are mounted on the main tower part 12 at a first height, and the other two are mounted on the main tower part 12 at a second, higher height. Two arms 13 mounted on the main tower part 12 at the same height extend away from the main tower part 12 along substantially opposite directions. Accordingly, the arms 13 are arranged symmetrically with respect to the main tower part 12. Thereby the loads introduced in the tower structure by the arms 13, including the loads introduced by the weight of the rotors 1 carried by the arms 13, are balanced.

[0083] The rotors 1 are mounted below the arms 13, i.e. suspended from the arms 13. This allows the rotors 1 to be readily hoisted into position on the arms 13 of the tower structure, or lowered to the ground, without the need for large cranes or the like. Thereby erecting the wind turbine 11, decommissioning the wind turbine 11 and/or replacing a rotor 1 is very easy and cost effective.

[0084] The arms 13 may be mounted on the main tower part 12 in a pivotal or rotational manner, allowing the upper and lower arms 13 to be rotated relative to each other, thereby allowing the rotors 1 mounted on the upper arms 13 to be moved away from a position directly above the rotors 1 being mounted on the lower arms 13. This will allow the rotors 1 mounted on the upper arms 13 to be lowered to the ground without colliding with the rotors 1 mounted on the lower arms 13.

[0085] It should be noted that the rotors 1 could, alternatively, be mounted above the arms 13 of the tower structure. As another alternative, the wind turbine could be of a single rotor type, i.e. the wind turbine may only comprise a single rotor, mounted on a tower structure, e.g. on top of a conventional tower.

[0086] FIG. 5 is a side view of a rotor 1 for a wind turbine according to a fifth embodiment of the invention. Similarly to the rotor 1 illustrated in FIG. 1, the rotor 1 of FIG. 5 comprises a hollow cylindrical king pin 2, and a hub 4 rotatably mounted on the hollow cylindrical king pin 2, the hub 4 carrying a number of rotor blades 14, two of which are visible. The rotor 1 further comprises a gear arrangement 7, comprising a number of pulleys 9 and belts 10, the gear arrangement 7 being arranged in front of the hub 4, along a direction facing the wind. A rotating shaft 8 interconnects the gear arrangement 7 and a generator 6 arranged behind the hollow cylindrical king pin 2, i.e. opposite with respect to the hub 4 and the gear arrangement 7. The rotating shaft 8 extends through the hollow cylindrical king pin 2.

[0087] The hollow cylindrical king pin 2 is mounted on an arm 13 of a tower structure via brackets 15 being bolted onto the hollow cylindrical king pin 2. The hollow cylindrical king pin 2 is mounted on a lower side of the arm 13, i.e. suspended from the arm 13.

[0088] The generator 6 is bolted onto an end part of the hollow cylindrical king pin 2 by means of bolts 16.

[0089] Electrical components 17 are mounted on the arm 13 of the tower structure, the electrical components 17 being electrically connected to the generator 6.

[0090] FIG. 6 is a cross sectional view of the rotor 1 of FIG. 5. It can be seen how the hollow cylindrical king pin 2 is mounted on the arm 13 of the tower structure via the bracket 15.