WO2010069325A1

WO2010069325A1 - Connection with connection devices for wind turbine

Info

Publication number: WO2010069325A1
Application number: PCT/DK2009/050335
Authority: WO
Inventors: Jesper Lykkegaard Andersen; Niels Christian Olsen
Original assignee: Vestas Wind Systems A/S
Priority date: 2008-12-17
Filing date: 2009-12-15
Publication date: 2010-06-24

Abstract

In order e.g. to provide a wind turbine connection which is able to withstand a relatively high torque, there is disclosed a connection for connecting a driving member (204), such as a wind turbine shaft and a driven member (206), such as an entrance shaft of a gearbox, in a wind turbine. The connection includes a plurality of connection devices (302) where each connection device includes at least one connection device surface provided with a form for being tensioned towards hollows of the driving member and the driven member, which hollows are fitted to the connection devices. The connection is provided for shear coupling the driving member to the driven member by providing the connection devices in the hollows so as to bridge the driving member to the driven member, and by tensioning each of the plurality of connection devices towards the driving member hollow and the driven member hollow.

Description

CONNECTION WITH CONNECTION DEVICES FOR WIND TURBINE

FIELD OF THE INVENTION

The invention relates to a connection with connection devices for a wind turbine. Among others, the connection provides a rigid connection with a high torque transferring capacity between a driving member such as a shaft or a hub of the wind turbine and a driven member, such as an entrance shaft of a gearbox or another driven member of the wind turbine.

BACKGROUND OF THE INVENTION

Wind turbines are used to gather wind energy and to transform the energy into another form of energy. For this purpose most wind turbines includes a shaft which in one end is coupled to blades of the wind turbine. The shaft is in the opposite end normally connected to a driven wind turbine part. This driven wind turbine part may be an entrance shaft of a gearbox or an entrance shaft or torque transferring member of an electric energy generator.

In modern wind turbines, a torque which is to be transferred in a connection between a driving member such as a hub or a shaft of the wind turbine and the driven member driven by the hub or the shaft is relatively high. The torque may lie in the interval between 3000 and 7500 kilo Newton meters. A purpose of the connection is to transfer torque, but the connection may also be used to transfer bending moment between the driving member and the driven member.

Various solutions have been provided in wind turbines in order to provide such connection. Examples of disadvantages with some solutions are that it has proved difficult or time consuming to connect and lock the shafts to each other and possibly also difficult to separate the shafts from each other again. Other solutions have proven that they were not able to withstand the torque or bending moments provided and yet some solutions have additionally or alternatively proven to be too expensive or relatively large when considering their overall effectiveness. SUMMARY OF THE INVENTION

It may be seen as an object of the present invention to provide an improved connection in a wind turbine between a driving member and a driven member in the wind turbine, a wind turbine including such a connection and a method of connecting a driving member and a driven member. Preferably, the invention alleviates, mitigates or eliminates one or more of the above or other disadvantages singly or in any combination.

In particular, it may be seen as an object of the invention to provide a solution which is found to be able to withstand the torque and possibly also a bending moment provided between a driving member in a wind turbine and a driven member in the wind turbine while still being relatively inexpensive and possibly also simple and effective to use.

Accordingly there is provided a connection for connecting a driving member and a driven member in a wind turbine, the connection comprising

- the driving member,

- the driven member, - a plurality of connection devices, and wherein

- a connection device comprises at least one connection device surface provided with a form for being tensioned towards the driving member and the driven member,

- the driving member comprises a plurality of hollows positioned in a radial distance offset from a centre of the driving member, where a driving member hollow is fitted to one of the at least one connection device surfaces,

- the driven member comprises a plurality of hollows positioned in a radial distance offset from a centre of the driven wind turbine part, where a driven member hollow is fitted to one of the at least one connection device surfaces, and - the connection is provided for shear coupling the driving member to the driven member by providing the connection devices in the hollows so as to bridge the driving member to the driven member, and by tensioning each of the plurality of connection devices towards the driving member hollow and the driven member hollow. Thus an improved connection in a wind turbine is provided. The improvement or advantage may lie therein that the described connection is able to withstand the torque provided between the driving member, such as a hub or a shaft, and a driven member, such as an entrance member of a gearbox or a generator in the wind turbine, while still being relatively compact, inexpensive and also simple and effective to use.

A possible advantage by providing the driving member and the driven member with a plurality of hollows as described is that relatively simple and yet effective connection elements may be fitted to the hollows, and vice versa, while these connection elements are still able to transfer the relatively high torque via the shear coupling or connection.

A possible advantage may be the connection is that a controlled tension or pretension can be applied to the connection device surfaces. When providing the connections devices with such tension on the connection surfaces towards the surfaces of the hollows, the connection may hold an even higher torque. This tension may be due to the connection devices being provided with pretension due to pressure being provided on the connection devices by one or more bolts. Alternatively or additionally the pretension may be provided by adjusting a position in the longitudinal direction of the driving member and/or of the driven member.

A possible advantage by providing a connection as described is that a rigid connection for a relative high torque and/or a relatively high bending moment can be made relatively compact. This may be due to the insertion and pretension of the connection devices and e.g. hereby not having to use a shrink disc in the connection. A possible advantage by the construction is that any flanges with a relatively large diameter of the driving or the driven member, compared to the flanges or minor enlargements of a member diameter shown herein, may be avoided. Such large flanges may be necessary when not using the proposed solution and a possible disadvantage thereof is that the flanges possibly prevents bearings being mounted from a certain direction, such as along an axial direction of the driving member or the driven member or prevents one or more bearings from being mounted in a certain manner. Still further, a possible advantage of the described connection is that the described connection is also able to withstand bending moments of a size as provided in a wind turbine of today. A possible advantage by the connection as described is also that it is particularly suited for transferring reversing and/or alternating torques. It is to be understood that the at least one connection device surface is a surface which transfers a load between the connected members.

When the connection device includes two conical connection device surfaces, a possible advantage is that it is rather simple to provide a pretension force on the connection device surfaces towards the driving member and the driven member.

Another possible advantage is that this form increases a surface area on a flange of the shaft for a bolt head, i.e. makes it possible to increase the size of the bolt head or the number of bolts.

When the connection device is cylindrical and/or comprises one or more circle formed surfaces, a possible advantage is that such shapes are rather easy to fabricate.

When the connection device comprises an inner bore in a centre of the connection device, a possible advantage is that this inner bore comprised in the connection device can be used to fix the connection device to one of the driving or driven member or used with a bolt or the like element in order to build a positive pretension force on the connection surfaces of the connection device.

When the inner bore is fitted for a bolt, possible advantages are that the connection devices are held in place, and that tension or pretension or a bias force may be provided to the connection devices surfaces by the bolt.

When the driving member hollow or the driven member hollow comprises a thread, and the bolt head is tensioned towards the driving member surface, a possible advantage is that an easily adjustable pretension force may be applied to the connection device surfaces via tensioning the bolt in the thread. The thread may also be provided in the driving member and the bolt may be tensioned towards the driven member. When a surface of the driving member hollow and a surface of the driven member hollow is in an opposite direction relative to an axis parallel with a driving member centre axis, a possible advantage is that a simple and yet effective embodiment is provided.

When a surface of the driving member hollow and a surface of the driven member hollow have a same direction relative to an axis parallel with the driving member centre axis, a possible advantage is that the driving member and the driven member may be assembled or disassembled without pushing the driving member and the driven member from each other in an axial direction, e.g. in a situation where ends of the connecting parts of the members are touching or close to each other in the axial direction.

When a corresponding hollow in the driving member and in the driven member is forming a pocket when the driving member and the driven member are connected, a possible advantage is that this pocket can be filled with a connection device in order to provide the connection.

When the pocket has an opening in a radial direction and in which pocket there is inserted a connection device, a possible advantage is that the hollows forming the pocket may be easy to manufacture.

In accordance with a method aspect of the invention there is provided a method of connecting a driving wind turbine member with a driven wind turbine member via a plurality of connection devices, the method comprising

- providing a plurality of connection devices for bridging hollows of the driving member with hollows of the driven member,

- bridging hollows of the driving member with hollows of the driven member by inserting a plurality of connection devices in the hollows, each connection device bridging a hollow in the driving member with a corresponding hollow in the driven member,

- tensioning the plurality of connection devices towards the driving member and the driven member, and hereby - shear coupling the driving member to the driven member. In general the various aspects and advantages of the invention may be combined and coupled in any way possible within the scope of the invention.

It is to be understood that any advantage mentioned may be seen as a possible advantage provided by the invention, but it may also be understood that the invention is particularly, but not exclusively, advantageous for obtaining the described advantage.

These and other aspects, features and/or advantages of the invention will be apparent from and elucidated with reference to the embodiments or in the claims described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be described, by way of example only, with reference to the drawings, in which

FIG. 1 shows a wind turbine, and

FIG. 2 is a side view of a hub and a nacelle of the wind turbine, and

FIG. 3 shows a connection in a wind turbine in the cross-section A-A indicated on figure 2, and

FIG. 4 shows the cross-sectional view B-B indicated in figure 2, and

FIG. 5 is a cross-section similar to A-A indicated on figure 2 prior to connection of an end part of a driving member and an end part of a driven member, and

FIGS. 6.1-6.3 illustrates a connection device, and

FIGS. 7 and 8.1-8.3 illustrates a connection and a connection device in accordance with a further embodiment of the invention, and

FIGS. 9.1-9.4 illustrates a connection and a connection device in accordance with a still further embodiment of the invention, and

FIGS. 10.1-10.3 illustrates alternative embodiments of connection devices to be provided in hollows with an inner hollow surface fitted therefore, and

FIGS. 11.1-11.2 illustrate a method in accordance with an embodiment of the invention. DESCRIPTION OF EMBODIMENTS

FIG. 1 shows a wind turbine 102 with a nacelle 104, and a hub 106 rotatably mounted to the nacelle 104 via a shaft (not seen in figure 1). The hub and the main shaft are examples of driving members of the wind turbine. The nacelle 104 is mounted on a wind turbine tower 108 via a rotary joint. The hub 106 of the wind turbine includes three wind turbine blades 110 attached to the hub. The hub rotates around a shaft centre axis of the wind turbine in a rotational plane substantially perpendicular to the centre axis.

FIG. 2 is a side view of the hub 106 and the nacelle 104. Some parts, such as a driving member 204, comprised in the hub and in the nacelle are shown in a cross-sectional view. The figure shows the driving member centre axis 214 running in a longitudinal direction in a centre of the driving member 204.

In particular, the figure shows a connection 202, with a driving member 204 with a length in a longitudinal direction and a driving member end with a radial extension, and a driven member 206 with a length in the longitudinal direction and a driven member end with a radial extension. In this example the driving member is a main shaft of the wind turbine and the driven member 206 is an entrance shaft of a gearbox 210 or an entrance shaft directly into a generator. The connection may alternatively be a connection between the hub 106 as the driving member and to the shaft or directly between the hub and a generator entrance member.

A purpose of the connection is to transfer a relatively high torque. The torque is among others resulting from the force provided by the wind via the driving member 204 and resistance provided by a system for generating energy coupled to the driven member 206. The connection may also be provided for transferral of e.g. bending moments.

The figure also illustrates two bearings 212 provided for bearing the driving member 204, is the shown example the main shaft, and for transferring bending moments from the main shaft to the tower 108. In the shown embodiment two bearings 212 are shown, but only one of these bearings, such as a front most of these two bearings 212, may be provided and a bearing 208 may also be used for transferring bending moments to the tower. The bearing 208 is in the shown embodiment mainly provided for bearing the driven member 206.

It follows from the figure that the size of the bearings 212, 208 and supporting structures for the bearings, such as the gearbox 210, is provided so as to follow the size or diameter of the first or second shafts. Still further any other components, such as gear wheels (not shown) and the like, possibly coupled to the driving member or the driven wind turbine member, follows or must be adapted to, at least to some extent, the size or diameter of the driving member or the driven member.

FIG. 3 shows the connection 202 in detail. The figure shows the driving member of the connection provided for shear coupling the driving member to the driven member by providing the connection devices 302 so as to bridge the driving member 204 to the driven member 206. The construction and manner of utilizing the connection devices 302 prevents shear forces perpendicular to surfaces of the connection device surfaces (shown in more detail in figure 6) from breaking the connection devices and hereby provides a shear connection or coupling of the wind turbine shaft with the driven wind turbine part.

The connection devices are provided with an inner centre bore and are in the shown embodiment fixed to a radial end of the driven member 206 with a bolt 304 through the inner bore. In the shown embodiment a head of the bolt 304 is tensioned on a surface of the driving member while a threaded part in an opposite end of the bolt is connected to a thread part in the driven member 206.

The figure also shows that the form and tolerances of the connection devices 302 and the form and tolerances of the driving member and the driven member hollows is constructed so as to have a distance 306 between the shafts when the driving member and the driven member are connected via the connection devices. Depending on a size of pretension of the connection device towards surfaces of the shafts, provided by tightening the bolts 302, the distance 306 decreases when tightening the bolts 304. It may be preferred to provide the forms and tolerances so that simple means, such as a feeler gauge, may be used to control and adjust the pretension.

FIG. 4 is the cross-sectional view B-B as indicated in figure 2. The figure shows that a plurality of bolts 304 with corresponding connection devices (seen in figure 3) and hollow openings 406. In the shown embodiment sixteen bolts 304 are shown offset a radial distance 402 from a centre 404 of the driving member 204. Depending on factors such as the size of the connection devices, a wind turbine shaft diameter or a size of torque to be transferred through the connection 202 other numbers, such as every integer between 8 and 24, of connection devices and corresponding bolts and hollows (shown in detail in figure 5) in the driving member and in the driven member may be chosen.

FIG. 5 is a cross-section similar to A-A indicated on figure 2 prior to connection of an end part 502 of the driving member 204 and an end part 504 of the driven member part 206. It can be seen from the figure that the driving member 204 have a plurality of hollows 506 positioned in a radial distance offset from a centre of the driving member. In the shown cross-section only two of the plurality of hollows 506 can be seen. It is also shown that both the hollows include a conical surface 508 fitted to one of the at least one conical connection device surfaces (shown in detail in figure 6).

In general, at least a part of the surface(s) of the hollows is fitted with a surface and dimensions which is a negative of at least a part of the outer surface(s) and dimensions of the connection devices.

Similarly figure 5 shows that the driving member 206 have a plurality of driving member hollows 505 with surfaces 512 fitted to one of the at least one conical connection device surface (shown in detail in figure 6). In a bottom end of the driven member hollow there is provided a thread 510 for the bolt 304 (shown in figure 3).

It is illustrated in the figure that a surface 508 of the conical driving member hollow 506 and a surface 512 of the conical driven member 206 hollow have conical surfaces 508, 512 in an opposite direction relative to an axis parallel with the driving member centre axis. An angle of the surfaces 508, 512, relative to the axis parallel with the driving member centre axis, is shown with the reference numbers 514 and 516, respectively. The angles 508, 512, which in the shown embodiment are equal or substantially equal as it follows the figure, are adapted to fit the angle 610 (illustrated in figure 6) of the connection device.

FIGS. 6.1-6.3 illustrate the connection device 302. The connection device in the shown embodiment includes two conical connection device surfaces 602, 604. Each conical connection device surface is provided on opposite sides of a mid cross-sectional line B-B as shown in the figure. The connection device in the shown embodiment is rotation-symmetrical around a centre line 606 through an inner bore 608 of the connection device.

An angle 610 of the double conical connection device surfaces with the centre line is in the shown embodiment the same for each surface 602, 604. The angle shown is approximately 20 degrees, but may be chosen from approximately 5 degrees to approximately 45 degrees. The approximate minimum angle is chosen so as to provide connection devices which are relatively easy to produce while also being self detachable from the surface which they have been tensioned against. The connection devices surfaces are the surfaces through which a load resulting from the torque is transferred.

A diameter 616 of the inner bore 608 may lie in the interval 020-030 mm. A length 612 of the connection device 302 may be in the interval 100-200 mm and a width 614 of the connection device may be in the interval 75-125 mm.

FIG. 7 and FIGS. 8.1-8.3 shows another embodiment of the connection of the wind turbine shaft (the driving member) with an entrance shaft (the driven member) of the gearbox. In the shown embodiment the connection device 702 and surfaces of the hollows in the driving member 204 and in the driven member 206 are provided so that the angle 704 of the surfaces is the same relative to an axis parallel with the driving member centre axis. The connection in accordance with this embodiment i.e. only includes a single conical connection device surface 802. A possible advantage hereby, relative to having two conical surfaces opposite each other as described for the embodiment of figure 3-6, may be that the driving member 204 and the driven member 206 can be separated without being separated in the longitudinal direction in order to insert or detach the connection devices 702.

In the embodiment shown in the previous figures a number of corresponding hollows 504 in the driving member and hollows 505 in the driven member are provided with orifices only in an axial direction.

FIGS. 9.1-9.3 illustrates an embodiment where a hollow 902 in the driving member 204 and a corresponding hollow 904 in the driven member 206 is forming a pocket 906 when the driving member and the driven member are aligned adjacent to each other or connected. It is also shown that the pocket has an opening 908 in a radial direction. In the pocket there is inserted a connection device 910. For simplicity there is only shown that each of the driving member 204 and the driven member 206 has three corresponding hollows 902 and 904. Any number of corresponding hollows may be provided. The number is provided in dependence of that there e.g. must be material enough between the hollows and e.g. in dependence of the torque and/or bending moment to be transferred in the connection.

In a lower left side of the figure the driving member 204 and the driven member 206 is shown without the connection device 910 inserted through the opening 908 in the pocket. At least a part of the inner bounding surface of the pocket is fitted to at least a part of an outer surface of the connection device 910.

In a lower right part of the figure the connection device is shown. It follows that the connection device is double conical and is provided with an inner bore. When the connection device is inserted in the hollows forming a pocket, the inner bore is aligned with bores in the driving member 204 and the driven member 206. When a bolt (not shown) is inserted through the bores, pretension of the connection device surface(s) towards inner surfaces of the hollows can be provided by tightening a nut (not shown) in an end of the bolt. When a flange 912 of the driven wind turbine part and of the shaft are both provided with large enough diameters the flanges may comprise a plurality of aligned bores (not shown) for each pocket. If the connection device comprises the same number of holes or bores, a plurality of bolt may be used to pretension or bias the connection device surfaces towards the hollows of the driving member and the driven member.

FIG. 10 illustrates alternative embodiments of the connection devices. At 1002 there is shown a connection device with concave connection device surfaces. At 1004 there is shown a connection device with convex connection device surfaces. At 1006 there is illustrated a connection device with connection device surfaces with steps, where each step increases or decreases a diameter of the connection device. Other constructions and forms of the connection devices and its surfaces, and in consequence of the surfaces of the hollows, may be provided. Such construction may even be a sphere formed connection device.

A common feature of the connection devices shown herein may be seen as that the devices are provided with connection device surfaces with one or more sloping surfaces or slip angle(s), which slopes or slip angles are adapted in a way that they among others enables the connection devices to be easily inserted in or detached from the hollows without the use of e.g. hydraulic means. The slope(s) is/are possibly also adapted so that a material thickness of the connection device at a given part is adapted to a shear force on the given part of the connection device. Still further a slope may have the possible advantage that an increased amount of material may be provided between each hollow fitted to the connection devices and possibly so that that bolts or nuts may be provided with an increased size, e.g. relatively to connection devices and corresponding hollows without one or more slopes as described herein.

FIGS. 11.1-11.2 illustrate a method of connecting a driving wind turbine member with a driven wind turbine member via a plurality of connection devices. The method includes providing 1102 a plurality of connection devices for bridging 1104 hollows of the driving member with hollows of the driven member, bridging hollows of the driving member with hollows of the driven member by inserting a plurality of connection devices in the hollows, each connection device bridging a hollow in the driving member with a corresponding hollow in the driven member and tensioning 1106 the plurality of connection devices towards the driving member and the driven member. Hereby there is provided a shear connection of the driving member with the driven member. In short, it is herein described that in order e.g. to provide a wind turbine connection which is able to withstand a relatively high torque, there is disclosed a connection for connecting a driving member, such as a wind turbine shaft and a driven member, such as an entrance shaft of a gearbox, in a wind turbine. The connection includes a plurality of connection devices where each connection device includes at least one connection device surface provided with a form for being tensioned towards hollows of the driving member and the driven member, which hollows are fitted to the connection devices. The connection is provided for shear coupling the driving member to the driven member by providing the connection devices in the hollows so as to bridge the driving member to the driven member, and by tensioning each of the plurality of connection devices towards the driving member hollow and the driven member hollow.

Although the present invention has been described in connection with preferred embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the present invention is limited only by the accompanying claims.

In this section, certain specific details of the disclosed embodiment are set forth for purposes of explanation rather than limitation, so as to provide a clear and thorough understanding of the present invention. However, it should be understood readily by those skilled in this art, that the present invention may be practised in other embodiments which do not conform exactly to the details set forth herein, without departing significantly from the spirit and scope of this disclosure. Further, in this context, and for the purposes of brevity and clarity, detailed descriptions of well-known apparatus, circuits and methodology have been omitted so as to avoid unnecessary detail and possible confusion.

In the claims, the term "comprising" does not exclude the presence of other elements or steps. Additionally, although individual features may be included in different claims, these may possibly be advantageously combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. In addition, singular references do not exclude a plurality. Thus, references to "a", "an", "first", "second" etc. do not preclude a plurality.

Claims

1. A connection for connecting a driving member and a driven member in a wind turbine, the connection comprising - the driving member,

- the driven member,

- a plurality of connection devices, and wherein

- the driven member comprises a plurality of hollows positioned in a radial distance offset from a centre of the driven wind turbine part, where a driven member hollow is fitted to one of the at least one connection device surfaces, and

- the connection is provided for shear coupling the driving member to the driven member by providing the connection devices in the hollows so as to bridge the driving member to the driven member, and by tensioning each of the plurality of connection devices towards the driving member hollow and the driven member hollow.

2. A connection according to claim 1, wherein the connection device is conical.

3. A connection according to claim 1, wherein the connection device comprises two connection device surfaces.

4. A connection according to claim 1, wherein the connection device is cylindrical.

5. A connection according to claim 1, wherein the connection device is double conical.

6. A connection according to any of the preceding claims, wherein the connection device comprises an inner bore through the connection device.

7. A connection according to claim 6, wherein the inner bore is fitted for a bolt, which bolt is provided for tensioning the connection device towards the driving member hollow and the driven member hollow.

8. A connection according to any of the preceding claims, wherein the driving member hollow or the driven member hollow comprises a thread for tensioning the connection device towards the driving member hollow and the driven member hollow.

9. A connection according to any of the preceding claims, wherein a surface of the driving member hollow and a surface of the driven member hollow are in an opposite direction relative to an axis parallel with a driving member centre axis.

10. A connection according to any of the preceding claims 1-8, wherein a surface of the driving member hollow and a surface of the driven member hollow have a same direction relative to an axis parallel with a driving member centre axis.

11. A connection according to any of the preceding claims, wherein a number of corresponding hollows in the driving member and in the driven member are provided with orifices only in an axial direction.

12. A connection according to any of the preceding claims, wherein a corresponding hollow in the driving member and in the driven member is forming a pocket when the driving member and the driven member are connected.

13. A connection according to claim 12, wherein the pocket has an opening in a radial direction and in which pocket there is inserted a connection device.

14. A wind turbine comprising a connection according to any of the claims 1-13.

15. A rigid connection for transferring torque and bending moments, the connection comprising

- a driving member,

- a driven member, - a plurality of connection devices, and wherein - a connection device comprises at least one connection device surface provided with a form for being tensioned towards the driving member and the driven member,

- the driven member comprises a plurality of hollows positioned in a radial distance offset from a centre of the driven member, where a driven member hollow is fitted to one of the at least one connection device surfaces, and - the connection is provided for shear coupling the driving member to the driven member by providing the connection devices in the hollows so as to bridge the driving member to the driven member, and by tensioning each of the plurality of connection devices towards a driving member hollow and a driven member hollow.

16. A method of connecting a driving wind turbine member with a driven wind turbine member via a plurality of connection devices, the method comprising

- providing a plurality of connection devices for bridging hollows of the driving member with hollows of the driven member, - bridging hollows of the driving member with hollows of the driven member by inserting a plurality of connection devices in the hollows, each connection device bridging a hollow in the driving member with a corresponding hollow in the driven member,

- tensioning the plurality of connection devices towards the driving member and the driven member, and hereby

- shear coupling the driving member to the driven member.