DESC: FIELD OF THE INVENTION:

The present invention relates to a wind turbine with an improved rotor lock, and to a rotor lock device for locking the rotor of a wind turbine.

BACKGROUND

It is often necessary, for the purpose of maintenance and repair of a wind turbine, to shut down the plant (wind turbine) and to prevent further rotation of the rotor blades and the main shaft/drive shaft. In order to shut down the plant, the pitches of the rotor blades are changed, as a result of which the plant slows to a halt. In addition, mechanical or hydraulic braking can be applied.

When the plant is at standstill, a rotor lock device can be deployed to lock the rotor. Such rotor lock devices are known and usually entail securing by means of a movable pin or bolt.

US2014/010656A1 discloses a fixation device for fixing a shaft connecting a rotor and a generator of a wind turbine. The fixation device comprises a rotor lock for locking the shaft providing a locking clearance and a rotor brake for braking the shaft. The rotor lock is arranged for positioning the shaft in a selectable angular position within the locking clearance of the rotor lock. The rotor lock includes a locking pin moveable by a locking actuator. When the locking pin is actuated by the locking actuator, the locking pin is forced into a locking recess of a rotor hub, so as to lock the rotational position of the rotor hub relative to a nacelle.
Figures 1 and 2 of the present invention as disclosed in the drawings are a typical construction known in the prior art. It shows an example of arrangement using a known locking device (13). In the arrangement of Figure 1 (i.e. viewed from above and offset from the axis of rotation A), a bearing assembly (1) is fixedly mounted on a main frame (2) of the wind turbine. According to this known system, a perforated disc (3) is arranged on the drive shaft (4) and rotates with the drive shaft, the latter being rotatable about axis A within bearing assembly (1). Provided in the disc (3) are a number (here 9) of through holes (5), having reinforcement rings (6).

As best seen in Figure 2 (i.e. viewed from below and offset from the axis of rotation A), a guide (8) comprising a guide tube (9) and shoulders (10) and (11) is integral with the main frame (2). One shoulder (10) is attached to a downwardly projecting bearing flange (12) which is integral with the main frame (2) and upon which the bearing (1) is supported.

In order to lock the rotor shaft (4), a pin or bolt (7) (not shown in Figure 2) is movable parallel to the axis A of the drive shaft (4) and within guide tube (9). At standstill of the wind turbine, the bolt (7) (as shown in Fig. 1) is moved away from the main frame (2), and is guided through a hole (5) in the perforated disc (3), i.e. until the bolt (7) at least protrudes slightly on an opposite side of the disc (3), as best seen in Figure 1. Thus, the drive shaft (4) and the rotor blades (not shown) can no longer rotate.

However, a disadvantage of the abovementioned arrangement is that, as large forces and torques are always at work at wind turbines, bolt (7), perforated disc (3) and, in particular, guide (8) for the bolt (7) on the main frame (2) (as well as bearing flange (12)) have to be designed to be very massive and bulky. This results in problems with regard to weight and size, both for transport of the components and during processing of the components and assembly of the wind turbine. Another drawback of the abovementioned arrangement arises from the fact that semi finished components for large mechanical structures are costly and hard to get.

There have been attempts, with other known arrangements, to divide/distribute the forces by employing a plurality of bolts. EP2381092A2 discloses a rotor lock assembly for use in a wind turbine. A bedplate frame is configured to support the rotor shaft, which includes a rotor lock disk. The rotor lock assembly includes a support frame, coupled to the bedplate frame and positioned adjacent to the rotor lock disk, a plurality of lock pin housings coupled to the support frame, each lock pin housing of the plurality of lock pin housings being configured to be positionable with respect to the rotor lock disk, and a plurality of lock pins configured to engage the rotor lock disk to facilitate limiting a rotation of the rotor shaft. The pins are provided covering an acute sector of the rotor lock disk.

However, it has been found that such multi-bolt arrangements have not worked satisfactorily as, due to the manufacturing tolerances, usually only one of the bolts is in contact/engaged when locking occurs, and therefore the force is not evenly induced/applied.

The present invention seeks to overcome the aforementioned problems and provide an improved wind turbine and rotor locking device therefor.

OBJECT OF THE INVENTION

An object of the present invention is to provide a wind turbine and rotor lock device thereof, wherein the construction of guide for the bolt on the main frame as well as bearing flange is less massive and bulky, which not only reduces the overall cost but also facilitates smooth operations.

Another object of the present invention is to provide a wind turbine and rotor lock device thereof, which provides for a smaller and/or less bulky rotor locking device, which facilitates east and smooth mounting, processing and/or assembly of the wind turbine.
Yet another object of the present invention is to provide a wind turbine and rotor lock device thereof, which facilitates mounting, processing and/or assembly of the wind turbine.

Another object of the present invention is to provide a wind turbine and rotor lock device thereof, which simplifies the operation and maintenance of the wind turbine.
SUMMARY OF THE INVENTION

According to one aspect of the invention there is provided a rotor lock device for a wind turbine, the wind turbine having a bearing assembly and a rotor shaft rotatable about an axis within the bearing assembly, the rotor lock device comprising: a lock disc mounted on a drive shaft, the lock disc having a plurality of first engagement elements, a lock shell connected to the bearing assembly, the lock shell having a plurality of second engagement elements, a lock ring having a plurality of third engagement elements configured for engaging, in use, with the plurality of second engagement elements, and a plurality of fourth engagement elements configured to be engagable, in use, with the plurality of first engagement elements, wherein the lock ring is configured to be axially movable, in use, between an unlock position, in which the fourth engagement elements do not engage with the first engagement elements, and a lock position, in which both (i) the third engagement elements engage with the second engagement elements and (ii) the fourth engagement elements engage with the first engagement elements, such that the lock shell and lock disc are connected in a form fitting manner.

An advantage of the invention is that the components of the rotor locking device are smaller and/or less bulky, thereby facilitating mounting, processing and/or assembly of the wind turbine. Semi finished components are cheaper to get and the invention also simplifies operation maintenance.

Preferably, the pluralities of first, second, third and/or fourth engagement elements are circumferentially arranged.

Preferably, the pluralities of first, second, third and/or fourth engagement elements are equally angularly spaced.

Preferably, the axes third and fourth engagement elements are aligned.

Preferably, the number of the first and fourth engagement elements, and/or the number of the second and third engagement elements, is the same.

Preferably, five or more of the first, second, third and/or fourth engagement elements are provided. More preferably, twelve of the first, second, third and/or fourth engagement elements are provided. Having at least five engagement elements, and preferably more, is to ensure that the forces and torques are actually introduced/applied via all engagement elements (e.g. projections).

Preferably, the first and second engagement elements comprise recesses or through holes and the third and fourth engagement elements comprise projections, or vice versa.

Preferably, the lock shell is detachably mounted on the bearing assembly. It is important that torques are not applied directly at the bearing, but are introduced into the bearing via the lock shell. This can ensure an even distribution of the forces and torques in the bearing. Furthermore, a defective/faulty lock shell can be configured so as to be replaceable.

Preferably, the rotor lock device further includes an actuator configured for moving, in use, the lock ring from the unlock position to the lock position, and vice-versa. Preferably, the actuator is configured for moving the lock ring relative to the rotor shaft. Preferably, the actuator is configured, in moving, in use, the lock ring from the unlock position to the lock position, for moving the lock ring away from the bearing assembly.

Preferably, the second engagement elements comprise bolts pressed into the lock ring.

According to another aspect of the invention there is provided a rotor locking arrangement comprising a bearing assembly for the rotor shaft for a wind turbine and, for locking the rotor shaft, a rotor lock device according to any of claims 1 to 13 of the appended claims.

According to another aspect of the invention there is provided a wind turbine comprising a bearing assembly and a rotor shaft rotatable about an axis within the bearing assembly, and, for locking the rotor shaft, a rotor lock device according to any of claims of the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details of the invention will become apparent from the drawings according to the description. In the drawings:

Figure 1 (PRIOR ART) is a perspective view from above of a known rotor locking arrangement,

Figure 2 (PRIOR ART) is a perspective view from below of the rotor locking arrangement of Figure 1;

Figure 3 shows an exploded view of a rotor locking device according to an embodiment of the invention; and

Figure 4 shows the rotor locking device of Figure 3, when fully assembled.

The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing figures.

DETAILED DESCRIPTION OF THE INVENTION

In the following, like reference numerals are used to designate like elements. The construction is as set out in respect of Figures 1 and 2, except as described hereinafter. All components are formed of high strength steel, unless stated otherwise.

Figure 3 discloses an embodiment of the present invention, which shows an exploded view of a rotor locking device (20) according to an embodiment of the invention. As before, a rotor shaft (4) is rotatable about axis A within a bearing assembly generally designated (1), which is attachable to the main frame (not shown) of a wind turbine, for example by bolting at bolt holes (21).

The rotor lock device (20) comprises several coaxially aligned components that are assembled by mounting and comprises, in sequence, a lock shell (22), a lock ring (23), a lock disc (24) and a cap ring (25). To assemble, first the lock shell (22) is fixedly attached to the bearing assembly (1). The lock shell (22) comprises a proximal ring (26), an axially extending annular wall (27) and a distal ring (28). The proximal ring (26) is attached to the bearing assembly (not shown) using a multitude of bolts (29) which pass through holes (not shown) in the proximal ring (26) and engage corresponding bolt holes (30) in the bearing assembly (1), the bolts (29) and bolt holes (30) having cooperating threads. At the same time, the annular wall (27) slides over and is spaced a suitable distance (a few mm to a few cm) from a distance ring (31) on the exterior of rotor shaft (4).

Next, the lock ring (23) is mounted to the lock shell (22). The latter includes a number of circumferentially arranged through holes (32) in the distal ring (28). In this embodiment, twelve through holes (32) are provided, however it will be appreciated that more or fewer may be used. Alternatively, recesses are employed instead of through holes (32). In this embodiment, the through holes (32) are equally angularly spaced around the distal ring (28); however, it will be appreciated that they may be irregularly spaced or arranged in groups of equal numbers such that consecutive groups are spaced apart.

In addition, in this embodiment, the lock ring (23) includes, on a proximal transverse surface thereof (not shown) a plurality of proximal projections (33) extending parallel to axis A. In this embodiment, there are the same number of proximal projections (33) as through holes (32); however, it will be appreciated that their number may be less than that of the through holes (32).

To mount the lock ring (23), the latter is presented to the distal ring (28), and the proximal projections (33) slid into through holes (32) in the distal ring (28). Thus, the lock ring (23) is securely retained, while being axially slidable, as will be described in more detail hereinafter.

Thereafter, the lock disc (24) is mounted to the rotor shaft (4). The lock disc (24) comprises an outer ring (34) integral with an annular flange (35) in which are provided axially extending grooves (36). In this embodiment, (12) grooves (36) are provided, equally angularly spaced around the annular flange (35). To mount the lock disc (24), the latter is presented to a shoulder portion (37) of the rotor shaft (4) and slid there over so that each groove (36) engages a respective feather key (38) on the shoulder portion (37).

In accordance with embodiments of the invention, lock disc (24) also includes a number of circumferentially arranged through holes (40) in the outer ring (34). In this embodiment, twelve through holes (40) are provided, however it will be appreciated that more or fewer may be used. Alternatively, recesses are employed instead of through holes (40). In this embodiment, the through holes (40) are equally angularly spaced around the outer ring (34); however, it will be appreciated that they may be irregularly spaced or arranged in groups of equal numbers such that consecutive groups are spaced apart.

In addition, in this embodiment, the lock ring (23) includes, on a distal transverse surface (41) thereof a plurality of proximal projections (42) extending parallel to axis A. In this embodiment, there are the same number of proximal projections (42) as through holes (40); however, it will be appreciated that their number may be less than that of the through holes (40). The proximal projections (42) may be formed by heads of bolts, or by nuts, secured onto lock ring (23).

In use, the distal projections (42) may engage through holes (40) in order to lock the rotor shaft (4) and prevent its rotation, or be disengaged therefrom in order for the rotor shaft (4) to be free to rotate.

Figure 4 shows the rotor locking device (20) of Figure 3, when fully assembled. As noted above, the lock ring (23) is axially slidable, and in order to lock the rotor, the lock ring (23) is moved (e.g. by an actuator, not shown) in the direction of arrow “L” such that distal projections (42) slide into and engage respective through holes (40) in outer ring (34) of lock disc (24). To unlock the rotor shaft, the motion of lock ring (23) is reversed through the action of the actuator (not shown), i.e. moved in the direction of arrow “U” such that distal projections slide out of and disengage from respective through holes (40) in outer ring (34) of lock disc (24).

For ease of reference each and every part of various embodiments as discussed and disclosed hereinabove are marked with a numeral, the details of which are appended below:

List of Reference Signs

1 bearing assembly
2 main frame
3 perforated disc
4 shaft
5 holes
6 reinforcement ring
7 bolt
8 guide
9 guide shaft
10 shoulder
11 shoulder
12 bearing flange
13 rotor locking arrangement
20 rotor locking device
21 bolt holes
22 lock shell
23 lock ring
24 lock disc
25 cap ring
26 proximal ring
27 annular wall
28 distal ring
29 bolts
30 bolt holes
31 distance ring
32 through holes
33 proximal projections
34 outer ring
35 annular flange
36 groove
37 shoulder portion
38 feather key
39 through holes
40 through holes
41 distal transverse surface
42 distal projections

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles described herein can be applied to other embodiments without departing from the spirit or scope of the invention. Thus, it is to be understood that the description and drawings presented herein represent a presently preferred embodiment of the invention and are therefore representative of the subject matter which is broadly contemplated by the present invention. It is further understood that the scope of the present invention fully encompasses other embodiments that may become obvious to those skilled in the art and that the scope of the present invention is accordingly not limited.
,CLAIMS:We claim:

1. A rotor lock device (20) for a wind turbine, the wind turbine having a bearing assembly (1) and a rotor shaft (4) rotatable about an axis (A) within the bearing assembly (1), the rotor lock device (20) comprising:
- a lock disc (24) mounted on a drive shaft (4), the lock disc having a plurality of first engagement elements (40),
- a lock shell (22) connected to the bearing assembly, the lock shell (22) having a plurality of second engagement elements (32),
- a lock ring (23) having a plurality of third engagement elements (33) configured for engaging, in use, with the plurality of second engagement elements (32), and a plurality of fourth engagement elements (42) configured to be engagable, in use, with the plurality of first engagement elements (40),
- wherein the lock ring (23) is configured to be axially movable, in use, between
o an unlock position, in which the fourth engagement elements (42) do not engage with the first engagement elements (40), and
o a lock position, in which both (i) the third engagement elements (33) engage with the second engagement elements (32) and (ii) the fourth engagement elements (42) engage with the first engagement elements (40), such that the lock shell (22) and lock disc (24) are connected in a form fitting manner.

2. A rotor lock device for a wind turbine as claimed in claim 1, wherein the pluralities of first (40), second (32), third (33) and/or fourth (42) engagement elements are circumferentially arranged.

3. A rotor lock device for a wind turbine as claimed in claim 1, wherein the pluralities of first (40), second (32), third (33) and/or fourth (42) engagement elements are equally angularly spaced.

4. A rotor lock device for a wind turbine as claimed in claim 1, wherein the axes of the third (33) and fourth (42) engagement elements are aligned.

5. A rotor lock device for a wind turbine claimed in claim 1 wherein the number of the first (40) and fourth (42) engagement elements, and/or the number of the second (32) and third (33) engagement elements, is the same.

6. A rotor lock device for a wind turbine as claimed in claim 1, wherein 5 or more of the first (40), second (32), third (33) and/or fourth (42) engagement elements are provided.

7. A rotor lock device for a wind turbine as claimed in claim 1, wherein 12 of the first (40), second (32), third (33) and/or fourth (42) engagement elements are provided.

8. A rotor lock device for a wind turbine as claimed in claim 1, wherein the pluralities of first (40) and second (32) engagement elements comprise recesses or through holes and the pluralities of third (33) and fourth (42) engagement elements comprise projections, or vice versa.

9. A rotor lock device for a wind turbine, as claimed in claim 1, wherein the lock shell (22) is detachably mountable on the bearing assembly (1).

10. A rotor lock device for a wind turbine as claimed in claim 1, wherein the rotor lock device further includes an actuator configured for moving, in use, the lock ring (23) from the unlock position to the lock position, and vice-versa.

11. A rotor lock device for a wind turbine as claimed in claim 10, wherein the actuator is configured for moving the lock ring (23) relative to the rotor shaft (4).

12. A rotor lock device for a wind turbine as claimed in claim 10, wherein the actuator is configured, in moving, in use, the lock ring (23) from the unlock position to the lock position, for moving the lock ring away from the bearing assembly (1).

13. A rotor lock device for a wind turbine as claimed in claim 1, wherein the third engagement elements (33) and/or the fourth engagement elements (42) comprise bolts pressed into the lock ring (23).

14. A rotor locking arrangement for a wind turbine comprising a bearing assembly (1) for the rotor shaft rotatable about an axis within bearing assembly (1) and, for locking the rotor shaft (4), a rotor lock device (20).