DESC:FIELD OF THE INVENTION

The present invention is directed to the technical field of wind turbines, in particular to wind turbines of the horizontal type, which means that the wind turbines comprise a horizontal axis and a rotor being directed against the wind.

Such wind turbines generally comprise a nacelle incorporating a drive train. The nacelle is mounted to a tower. A rotor with one or more rotor blades, particularly with three rotor blades, is connected to the drive train via a hub, to which the rotor blades are mounted. The rotor rotates around its rotational axis. In general, the drive train comprises a gear device and a generator device. Usually, the rotor is coupled to a drive shaft of the gear device, said drive shaft in turn being coupled to an output shaft of the gear device. The gear device is coupled to the generator device which comprises a rotor component and a stator component for generating electric energy. In particular, the output shaft of the gear device is coupled to a generator shaft of the generator device, said generator shaft being coupled to the rotor component of the generator device as well.

The present invention relates to an interface device for connecting the output shaft of a gear device to a generator shaft of a generator device of a drive train of a wind turbine. Further, the present invention relates to a drive train of a wind turbine. In addition, the present invention is also directed to a wind turbine.

BACKGROUND OF THE INVENTION

Such a solution is disclosed in EP 2 508 753 B1. This known solution provides a drive train wherein the generator device and the gear device are mounted in very short way, such being optimized with regard to the required installation space. For this purpose, the output shaft of the gear device is mounted to a connection flange, and the generator shaft of the generator device is mounted to a connection flange as well. Both connection flanges are rotatably mounted to each other. Furthermore, an electric isolation may be provided between the front sides of both connection flanges.

Although this known solution provides advantages with regard to the required installation space, it still shows a number of other drawbacks. First of all, this known solution is very expansive to manufacture. Moreover, it is not easy to replace the different components of the drive train, since the connection flanges are located inside the generator device. In addition, maintenance is very difficult to perform. Last but not least it is a further drawback of this known solution that it provides small or no misalignment compensation.

OBJECTIVE OF THE INVENTION

Starting from the aforementioned state of the art, it is the object of the present invention to provide an interface device for connecting an output shaft of a gear device to a generator shaft of a generator device of a drive train of a wind turbine that avoids the aforementioned drawbacks.

According to the invention, the object is solved by the interface device, which is the first aspect of the invention, by the drive train, which is the second aspect of the invention, and by the wind turbine, which is the third aspect of the invention.

Further features and details of the invention become apparent from the claims, from the description as well as from the drawings.

Therein, features and details which are described in connection with one aspect according to the invention apply with respect to their disclosure in their entirety also to the other aspects according to the invention, so that any statements made with respect to one aspect of the invention also apply to their full extent to the other aspects of the invention and vice versa.

SUMMARY OF THE INVENTION

The underlying concept of the present invention is that a disc is used that is capable of transferring the torque by using large teeth and which is provided between the gear device side and the generator device side. In particular the output shaft of the gear device is connected to a first hub device, and the generator shaft of the generator device is connected to a second hub device. Both hub devices are connected or coupled to one another by having the disc being located between them.

The present invention according to its three aspects is directed to the technical field of wind turbines, in particular to the technical field of horizontal wind turbines. Such wind turbines are generally known in the prior art.

According to a preferred embodiment, the wind turbine comprises a nacelle which incorporates a drive train. The drive train transmits the rotor speed to the generator where it is converted into electric energy. Therefore, the wind turbine comprises a rotor being connected to said drive train, said rotor preferably comprising a hub and at least one rotor blade, preferably three rotor blades. The rotor is pivotally mounted around a rotational axis to the drive train. In order to transform the rotational energy of the rotor into electric energy, the drive train, to which the rotor of the wind turbine is mounted, comprises a number of different components. One of these components is a gear device. At its entrance side, the gear device is connected to the rotor via a drive shaft, a slow running drive shaft for example. The rotor is connected to said drive shaft via its rotor hub. On its exit side, the gear device comprises an output shaft, a fast running output shaft for example. The gear device has the function to transform the low speed or low revolution and the high torque of the drive shaft into a high speed or high revolution and a small torque of the output shaft. The gear device is connected to the generator device. In particular the output shaft of the gear device is coupled to a generator shaft of the generator. The generator device generates electric energy from the rotational energy which is provided by the gear device. For this purpose, the generator device preferably comprises a stator component and a rotor component, said rotor component being coupled to the generator shaft.

According to the first aspect of the present invention, an interface device is provided, said interface device being provided for connecting an output shaft of a gear device to a generator shaft of a generator device of a drive train of a wind turbine, whereby the interface device comprises a first hub device, said first hub device being adapted for being connected to the output shaft of the gear device, and a second hub device being adapted for being connected to the generator shaft of the generator device. The interface device is characterized by a disc being provided between the first hub device and the second hub device, said disc being a glass fibre disc or a disc made of a material having the same properties like glass fibres, said disc being connected to the first hub device and to the second hub device by means of a tooth-connection.

According to this first aspect, the present invention is directed to a gear device-generator device-interface. By means of this interface device, the gear device can be directly connected to the generator device, which allows a significant reduction with regard to the required installation space.

For this purpose, the interface device comprises a first hub device. The first hub device has a specific function, namely it is adapted for being connected to the output shaft of the gear device. This means, in the operational state of the interface device, the output shaft of the gear device is coupled or connected to the first hub device. This goal can be achieved in different ways. Preferred embodiments are described in more detail further below. The first hub device receives and houses the output shaft of the gear device and is coupled and connected to the disc. The first hub device has the function of transferring torque from the output shaft to the disc. Preferably the inside of the first hub device, which is the inner space of the hub device, fits exactly to the output shaft. Preferably, the output shaft is centered inside the first hub device. Coarse teeth on the first hub device transfer the torque from the first hub device to the disc. Therefore, the first hub device is adapted to fixate the output device as well as the disc in axial direction. By means of the coarse teeth of the first hub device, the disc is prevented from moving in radial direction. These functional features of the first hub device are explained in more detail further below. According to a preferred embodiment the first hub device is constructed such that oil is capable of flowing through and out of the first hub device.

In addition, the interface device comprises a second hub device. This second hub device has a specific function as well, namely it is adapted for being connected to the generator shaft of the generator device. This means, in the operational state of the interface device, the generator shaft of the generator device is coupled or connected to the second hub device. This goal can be achieved in different ways. Preferred embodiments are described in more detail further below. The second hub device has the function of connecting the disc with the generator shaft. Preferably, as will be explained further below, the second hub device is coupled to the disc by means of coarse teeth projecting from the second hub device. Preferably, the second hub device is connected to the generator shaft by means of a serration connection, a Hirth connection for example. This will be explained in more detail further below. In accordance with the function of the first hub device, the second hub device as well is adapted for fixing the disc in axial direction. Furthermore, the second hub device is provided in a way that it is fixed in axial direction as well and that it is centred with regard to the generator shaft. Similar to the first hub device, according to a preferred embodiment the second hub device is constructed such that oil is capable of flowing through and out of the second hub device.

In particular, the second hub device does not make contact with other metallic parts of the drive train or the wind turbine, which makes the coupling electrically insulated.

According to the present invention, the interface device comprises a specific disc being provided between the first hub device and the second hub device.
Generally, the present invention is not delimited to specific types of disc materials.

The disc is located between the first hub device and the second hub device. It is a general function of the disc to transfer torque from the first hub device to the second hub device. For this purpose, it is preferably provided that the disc comprises coarse teeth, which are in engagement with the coarse teeth of the first and second hub devices. Preferred embodiments thereof are described in more detail further below. It is another functionality of the disc that it is capable of absorbing axial forces without moving. In particular the disc is made of an electrically insulating material. As described above with regard to the first and second hub devices, the disc may be surrounded by oil. Therefore, the disc should be made of a material which is resistant against oil. Furthermore, the disc should be made of a material which prevents or reduces any shocks in the drive train. Thus, the disc should be made of a material which is capable of damping such shocks.

In a preferred embodiment, the disc is a glass fibre disc.

Preferably, the glass fibre disc is made of a glass fibre material or of a glass fibre reinforced plastic material or of a glass fibre composite material. According to a preferred embodiment, the disc is made of a glass fibre-reinforced polymer composite.

Preferably, the glass fibres used for the disc are so called E-glass fibres. E-glass or Electrical-glass is generally known in prior art. E-glass fibres are typically manufactured by using melt spinning techniques. According to a preferred embodiment, E-Glass is a low alkali glass with a typical nominal composition of SiO2 54wt%, Al2O3 14wt%, CaO+MgO 22wt%, B2O3 10wt% and Na2O+K2O less then 2wt%. Some other materials may also be present at impurity levels

Glass fibres and materials made thereof or containing glass fibres have a high tensile strength, a high compressive strength and a high breaking elongation. Furthermore, such materials have good thermal and insulating properties. Such materials are easy to process and they are resistant against oil and grease. Good electrical insulating properties together with a high resistance against fatigue, combined with a low E-modulus make glass fibre materials being preferred materials for being used as or in the disc according to the present invention, in order to transfer the torque. A glass fibre disc is easy and cheap to manufacture because no mold is needed to produce the part. A plate can be cut into the right shape with a water cutter or a laser cutter for example. Therefore, there are almost no limitations in the dimensions of a glass fibre disc.

Other materials than glass fibre materials which show the same or similar properties and characteristics as mentioned further above, in particular similar physical and/or chemical properties and characteristics, are applicable for the disc as well. Therefore, such other materials are covered by the scope of the present invention as well.

According to a preferred embodiment, the disc can easily be removed or replaced. In this embodiment the disc is a separate member which is loosely placed between the first hub device and the second hub device.

According to another preferred embodiment, the disc can be connected to the first hub device and to the second hub device by means of a glue connection. This embodiment will be described in more detail further below.

Misalignment is compensated by the disc that preferably acts in a way as a damping device. The coupling is located in between the generator device and the gear device, a gearbox for example, making it very accessible for maintenance.

According to the present invention, the disc is connected to the first hub device and to the second hub device by means of a tooth-connection.

In particular a tooth-connection is a connection between two pieces, wherein at least one piece comprises teeth protruding from a surface, whereby these teeth mash with grooves in the second mating piece, particularly in order to transfer torque. A preferred embodiment for such a tooth-connection, which will be described in more detail further below, is a gear connection. In this case the glass fibre disc is preferably provided as a gear or in the shape of a gear.

In particular, a gear connection is a type of connection in order to provide a form-fitting transfer of rotational movements and torque between different components, between the first and second hub devices in the present case. In particular, a gear is a ring-shaped member having a number of teeth, said teeth being evenly or equidistantly located or arranged over the circumference of a ring-shaped base part. The teeth protrude from the ring-shaped base part of the gear, either in radial or axial direction. In particular a radial protrusion means that the teeth protrude in an outward direction as seen from the centre of the gear. In particular an axial protrusion means that the teeth protrude in the direction or line of an axis, the central axis of the gear for example, its longitudinal axis for example. In this case, according to a preferred embodiment the teeth can protrude from a front face of the gear.

The tooth-connection according to the present invention could be defined as a spline connection as well. A spline connection comprises teeth on a substrate, a base member or a shaft for example, that mash with grooves in a mating piece and transfer torque and rotational movements.

According to a preferred embodiment, the first hub device is provided as a hollow member, in particular as a hollow cylindrical member or as a bush, socket or any other female connector, said first hub device comprising a first end with a first front side, said first front side having an opening for receiving the output shaft of the gear device, said hollow member particularly being adapted for receiving a shaft of the gear device, a spline shaft for example. The teeth of such a spline shaft transfer torque to the first hub device. In order to reduce wear on the splines, the spline shaft is preferably adapted for being able to be centred within the first hub device. According to a preferred embodiment, the shaft, in particular the spline shaft, is locked in axial direction, by means of a lock disc for example, in order to prevent the shaft moving inside the first hub device thus reducing the danger of failure and fatigue. The lock disc is located around the output shaft, in particular the spline shaft, and may get fixed by means of bolts. It holds the shaft inside the first hub device, but preferably, not completely locking it, such that there is a -small – room to move. If oil is used as mentioned further above, such oil is also used to lubricate the shaft, in particular the teeth of the splined shaft. The shaft is preferably constructed and arranged in such a manner that oil is capable to flow through the shaft and back from the shaft.

The walls of such a hollow member border an inner space, said inner space being adapted to or being capable of receiving the output shaft of the gear device. If the output shaft is a spline shaft, the inner surface of the hollow member, which is directed towards the inner space thereof, comprises a spline configuration as well. This means that teeth are provided respectively, said teeth being provided in order to comb with corresponding teeth on an outer surface of the spline shaft. That means that the teeth of the hollow member come into engagement with the teeth of the spline shaft. Preferably the teeth of the hollow member and/or the teeth of the spline shaft are crowned.

A spline shaft is generally known in the prior art. For example, the characteristics of such spline shafts are defined in DIN 5480, so that the principle or geometry and basic construction of that component is generally known by the skilled person.

According to another preferred embodiment the output shaft of the gear device is coupled to the first hub device by means of a press-fit-connection. A press-fit-connection is preferably generated by forcing the end of the output shaft into the first hub device. For example, such a press-fit-connection can be achieved by applying force, by heating up one element and cooling down the other element, or the like. Press-fit-connections per se are known in the prior art.

A danger of misalignment is compensated by a splined shaft, from which the teeth are preferably crowned, or in its entirety by the disc, in particular by the glass fibre disc, when a press-fit connection is used whereby the glass fibre disc that acts in a way as a damping device.

According to a preferred embodiment, the first hub device comprises a second end with a second front side, said second front side being directed towards the second hub device, whereby the first hub device comprises a number of coarse teeth, in particular 5 to 10 teeth, preferably 8 teeth, said coarse teeth protruding from the second front side in axial direction towards the second hub device, or protruding radially from the second end of the first hub device.

If a splined shaft, preferably with crowned teeth, is used, the torque is transferred from the output shaft of the gear device to the first hub device via the spline connection. The same results can be achieved by using a smooth shaft which is pre-fitted into the first hub device. The first hub device, which is afterwards sometimes called inner hub as well, holds the splined shaft and is fitted with coarse teeth on the outside.

In particular a coarse tooth is a large tooth having a width, which is equal or bigger than the height of the tooth. The coarse tooth is preferably dimensioned such that it is capable of reducing the surface pressure on the disc during operation. The present invention is not delimited to a specific number of teeth. According to a preferred embodiment the first hub device comprises 8 of such teeth. The coarse teeth are evenly or equidistantly provided over the circumference of the first hub device.

According to this embodiment, two different alternatives are described, how the tooth can protrude from the first hub device. According to a first alternative, the teeth protrude from the second front side in axial direction towards the second hub device. According to the second alternative, the teeth protrude radially from the second end of the first hub device. In a preferred embodiment the teeth protrude according to the first alternative.

According to a preferred embodiment, the second hub device is provided to be connected to the generator shaft via a serration connection, in particular via a Hirth serration connection, said second hub comprising a first end with a first front side, said serration connection being provided at the first front side.

In particular a serration connection is a connection between two members, wherein both members comprise a row of tooth projecting from a surface, and a number of grooves, wherein alternately a tooth and a groove is provided in said row. These teeth and grooves mash with corresponding groves and teeth on the second member. In the present case, one of these members is the second hub device, a front side or end side of this second hub device for example, and the other member is the generator shaft, a front side or end side of the generator shaft for example, whereby both front or end sides are directed towards each other.

A Hirth serration is a specific type of mechanical connection being used to connect two pieces of a together, the generator shaft and the second hub device in the present case. It is characterized by tapered teeth that mesh together on the end faces or front faces of both components. Hirth serrations per se are known in the prior art. It is an advantage of such Hirth serrations that they show high resistance to wear and that they are self-centering.

According to a preferred embodiment, a Hirth serration is fitted on the back of the second hub device which is sometimes called outer hub in the following as well. Such a Hirth serration preferably ensures self-centering properties. The generator shaft is also fitted with a Hirth serration. The serration of the outer hub and the generator shaft can be pressed together, by using bolts for example, with optionally making use of a transition piece. In using such a Hirth joint the generator shaft and the second hub device to be connected via their respective front faces comprise splines at their front faces.

Preferably, the second hub device comprises a second end with a second front side, said second front side being directed towards the first hub device, whereby the second hub device comprises a number of coarse teeth, in particular 5 to 10 teeth, preferably 8 teeth, said coarse teeth protruding from the second front side in axial direction towards the first hub device, or protruding radially from the second end of the second hub device. With regard to the configuration and number of the coarse teeth, full reference is made to the disclosure of the coarse teeth of the first hub device.

According to a preferred embodiment the disc is a spur gear or has the shape of a spur gear having a ring-shaped base member and comprising a number of coarse teeth, in particular 5 to 10 teeth, preferably 8 teeth, protruding radially outwardly from the ring-shaped base member, and further comprising a number of coarse teeth, in particular 5 to 10 teeth, preferably 8 teeth, protruding radially inwardly from the ring-shaped base member.

With regard to the general function of a gear, as well as with regard to the configuration and number of the coarse teeth, full reference is made to the respective disclosures further above.

The present invention is not delimited to the number of coarse teeth being described with regard to the first hub device, the second hub device and the glass fibre disc, such that these components, having different numbers of coarse teeth, are applicable as well. Preferably, all components comprise the same number of coarse teeth.

In particular, a spur gear is a ring-shaped member having a base portion, and the gearing, which is the teeth, protrudes from the outer circumference of base portion and/or from the inner circumference of the base member, such that the teeth are directed radially outwards and/or radially inwards from the base portion.

According to a preferred embodiment, the disc is fitted over the teeth of the first hub device, making it able to transfer the torque. These teeth of the disc are preferably provided at the inner side of the disc. Coarse teeth are also fitted on the outside of the disc, in which the second hub device is fitted.

According to a preferred embodiment, the coarse teeth of the disc comb with the coarse teeth of the first hub device and with the coarse teeth of the second hub device. That means, that the respective coarse teeth come into engagement with one another. By means of the coarse teeth, rotational movements and torque gets transferred from the first hub device via the disc to the second hub device. This goal is particularly achieved by means of the form closure of the combing teeth which are in engagement with one another.

According to yet another preferred embodiment, the first hub device is provided radially inwardly from the second hub device, the disc is provided radially between the first hub and the second hub, whereby the coarse teeth protruding radially outwardly from the disc comb with the coarse teeth of the second hub device and the coarse teeth of the disc protruding radially inwardly from the disc comb with the coarse teeth of the first hub device. In this case, the first hub device can be defined as the inner hub device, whilst the second hub device can be defined as the outer hub device.

According to yet another preferred embodiment, a first pressure plate is provided on a front side of the disc and/or a second pressure plate is provided at the back side of the disc. By use of such pressure plates, the disc can easily be removed or replaced by loosening the pressure plates. According to a preferred embodiment, two pressure plates are fitted on the front and back side of the disc, each pressing it tightly to prevent delamination of the disc and absorb axial forces. Preferably, the pressure plates are connected and fixed by using bolts.

According to yet another preferred embodiment, or in addition to the aforementioned embodiment, the disc is connected to the first hub device and/or to the second hub device by means of a glue connection. According to this embodiment the disc is glued onto or in the two hub devices. By doing so, the surface area, on which loads are applied, is preferably increased. Due to the use of such a glue connection the whole surface of the disc is used in transferring the torque. This leads to lower surface pressure and a smoother transfer of loads. If no glue connection is used the coarse teeth of the first and second hub device push against the surface of the disc and there is only a small surface available to transfer the torque.

The present invention is not limited to specific glue materials. In case that the disc is a glass fibre disc and that the glass fibres use epoxy as their fibre matrix, it is preferred that the glue for the glue connection is based on epoxy.

As mentioned further above, the first hub device, the second hub device and the glass fibre disc each comprise a number of coarse teeth. Besides these coarse teeth, each component comprises a number of coarse grooves as well. A coarse groove is the space between two adjacent coarse teeth.

In particular a coarse groove is a large groove or space between two adjacent teeth having a width, which is equal or bigger than the depth of the groove. The present invention is not delimited to a specific number of grooves. In particular each coarse tooth is flanked by two adjacent coarse grooves, and vice versa. According to a preferred embodiment, the number of coarse teeth of a component is equal to the number of coarse grooves thereof. For example, if a component comprises 8 coarse teeth, it comprises 8 coarse grooves as well.

According to a preferred embodiment, the interface device is constructed or provided in such a way that oil or other lubricants can freely flow through the connection.

In the following, a preferred embodiment for an interface device according to the present invention will be described.

A splined shaft with crowned teeth is used to transfer the torque from the gear device to a first hub device. The first hub device, which is called inner hub as well, holds the splined shaft and is fitted with coarse teeth on the outside. A glass fibre disc is fitted over the teeth of the inner hub, making it able to transfer the torque. Two pressure plates are fitted on the front and back side of the plate, pressing it tightly to prevent delamination of the disc and absorb axial forces. Coarse teeth are also fitted on the outside of the disc in which a second hub device is fitted, after this called outer hub. The same principle with the pressure plates is applied here. The outer hub makes no contact with other steel parts, making the coupling electrically insulated. On the back of the outer hub a Hirth serration is fitted. This ensures self-centering properties. The generator shaft is also fitted with a Hirth serration. The serration of the outer hub and the generator shaft are pressed together using bolts, with optionally making use of a transition piece.

According to the second aspect of the invention, a drive train of a wind turbine is provided, said drive train comprising a gear device and a generator device being connected to one another by means of an interface device, said interface device being provided for connecting an output shaft of the gear device to a generator shaft of the generator device, whereby the interface device comprises a first hub device, said first hub device being connected to the output shaft of the gear device, and a second hub device, said second hub device being connected to the generator shaft of the generator device. The drive train is characterized by a disc being provided between the first hub device and the second hub device, said disc being a glass fibre disc or a disc made of a material having the same properties like glass fibres, said disc being connected to the first hub device and to the second hub device by means of a tooth-connection.

In particular, the interface device of the drive train is provided according to the first aspect of the present invention.

With regard to the construction and the function of the drive train and its components, full reference is also made to the description further above, in particular of the first aspect of the invention as disclosed further above, as well as to the description of the underlying concept of the present invention. In particular the drive train comprises one or more features as described in detail further above.

According to a preferred embodiment, the gear device comprises an output shaft, said output shaft being received inside the first hub device. For example, the output shaft can be provided as a spline output shaft or as a shaft being press-fitted into the first hub device. According to yet another preferred embodiment, the generator shaft is connected to the second hub device by means of a serration connection, in particular by means of a Hirth serration connection.

According to a preferred embodiment, the drive train can be assembled by making use of the following assembly procedure:

In one step, the generator shaft is connected to the second hub device. Both components preferably comprise a Hirth serration at their respective front faces being directed towards each other. Both components, which might be slightly oiled, are pressed against each other such that the splines of the respective Hirth serrations come into contact and engage with each other. Bolts that go through respective holes in the second hub device may be screwed into respective threated holes in the generator shaft.

In another step the first hub device is connected to the output shaft. For this purpose, the output shaft, in particular a splined output shaft is introduced into the first hub device and is being received therein. According to another embodiment, the output shaft can be press-fitted into the first hub device. By means of a fixing device, a lock disc for example, the output shaft can be fixed at the first hub device.

The disc, in particular a glass fibre disc, is mounted between a front face of the first hub device and a front face of the second hub device both front faces being directed towards each other. Since the first and second hub device as well as the disc comprise coarse teeth, the coarse teeth come into engagement with each other. According to one embodiment, the disc, which is freely mounted between the two hub devices, gets fixed by means of two pressure plates in order to avoid an axial movement of the disc. According to a different embodiment or in addition to the aforementioned embodiment, the disc can be coupled to the first and second hub device by making use of a glue connection, such that the disc is glued to the first and second hub device.

In the latter embodiment, for assembling the drive train, the disc is glued to either one of the first or second hub device, to the first hub device for example. When a press-fit connection is used, the disc can’t be glued to the first hub before fitting the output shaft. Press-fitting requires a rather large temperature difference between the two parts. Glue can’t withstand these temperatures.

Afterwards, all components are assembled to each other such that the respective coarse teeth of the different components come in engagement and comb with each other. In case that a glue connection is used it has to be preferably ensured that both surfaces of the disc as well as the surfaces of the teeth of the disc are sufficiently covered with glue. If a glue connection is used, the gluing step is preferably performed before mounting the entire drivetrain together. In this embodiment the coupling is first fully assembled and after that, placed as a whole between the generator device and gear device. Preferably, the mounting is performed with the gear device and the generator device in vertical position, i.e. the generator device is tilted and lifted above the gear device so that the coupling flange is facing downwards.

According to the third aspect of the present invention, a wind turbine is provided, said wind turbine comprising a nacelle, a drive train being mounted inside said nacelle and a rotor, which is pivotally mounted around a rotational axis to the drive train. According to the present invention, the drive train is provided according to the second aspect of the invention.

With regard to the construction and the function of the wind turbine and its components, full reference is also made to the description further above, in particular of the first aspect of the invention as disclosed further above, to the second aspect of the invention as disclosed further above, as well as to the description of the underlying concept of the present invention. In particular the wind turbine comprises one or more features as described in detail further above.

The present invention according to its three aspects has a number of advantages, which are particularly as follows:
- Parts with high wear are easy replaceable
- Parts with high wear are cheap and easy to manufacture because most parts can
be produced with laser or water cutting technology
- The connection is easy to maintain because it can be taken apart inside a WTG
- The connection is electrically insulated
- The connection compensates for misalignment
- The disc has a dampening effect
- Cracks in the disc are easy spotted as it is always visible
- The disc is not affected by chemicals like oil
- The disc is able to operate in the temperatures occurring during
operation
- The disc can be replaced without using special tools
- The connection is easy scalable for larger or smaller applications by enlarging the
diameter of the disc or increasing its thickness
- Assembly of the connection is easy as it only requires bolts to connect all the parts
- The entire connection is lubricated and therefore durable. Oil can flow through the
entire connection

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be explained in more detail with respect to exemplary embodiments with reference to the enclosed drawings, wherein:

Figure 1 shows a schematic view of a wind turbine incorporating a drive train according to the present invention;
Figure 2 shows an exploded view of a drive train of the present invention comprising an interface device according to the present invention;
Figure 3 shows a cut side view of the assembled drive train according to
Figure 2;
Figure 4 shows another side view of the assembled drive train according to
Figure 2;
Figure 5 depicts a top view on the front end of the drive train of Figure 4 from the left;
Figure 6 depicts a sectional view of the drive train according to section A-A shown in Figure 4; and
Figure 7 depicts a sectional view of the drive train according to section B-B shown in Figure 4.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 shows a wind turbine 1 of the horizontal type with a tower 12 and a nacelle 11. Nacelle 11 is rotatable mounted to the tower 12. Nacelle 11 incorporates a drive train (not shown), said drive train being mounted inside nacelle 11 and being connected to a rotor 13. Rotor 13 comprises three rotor blades 15 which are mounted to a hub 14. Hub 14 of rotor 13 is connected to a drive shaft of the drive train. The rotor blades 15 are adjustably mounted on the hub 14. This is realized by means of pitch drives, said pitch drives being part of a pitch system. The pitch system controls the rotor speed to given set points. By means of pitch-drives, the rotor blades 15 may be moved about a rotor blade axes into different pitch positions. The rotor 13 is rotatable connected to the drive train via its rotational axis.

The drive train, which is shown in more detail in Figures 2 to 7, transmits the rotor speed to a generator device 24, where it is converted into electric energy. In order to transform the rotational energy of the rotor 13 into electric energy, the drive train 20, to which the rotor 13 of the wind turbine 10 is mounted, comprises a gear device 21. At its entrance side, the gear device 21 is connected to the rotor 13 via a drive shaft (not shown), a slow running drive shaft for example. The rotor 13 is connected to said drive shaft via its rotor hub 14. On its exit side, the gear device 21 comprises an output shaft 22, a fast running output shaft for example. The gear device 21 has the function to transform the low speed or low revolution and the high torque of the drive shaft into a high speed or high revolution and a small torque of the output shaft 22. The gear device 21 is connected to the generator device 24. In particular the output shaft 22 of the gear device 21 is coupled to a generator shaft 25 of the generator device 24. The generator device 24 generates electric energy from the rotational energy which is provided by the gear device 21. For this purpose, the generator device 24 preferably comprises a stator component and a rotor component, said rotor component being coupled to the generator shaft 25.

The gear device 21 is connected to the generator device 24 by means of an interface device 30 which will now be explained in more detail with regard to Figures 2 to 7. These Figures depict different views of the interface device 30 and the components of the gear device 21 and the generator device 24 being assembled thereto.

As particularly evident from Figure 2, the interface device 30 comprises a first hub device 31 and a second hub device 38.

The first hub device 31 is a hollow cylindrical member having a first front side 32a at its first end 32, said first front side 32a incorporating an opening 33. The walls of first hub device 21 border an inner space 34. Furthermore, the hollow first hub device 31 is comprised with a splined inner surface 35.

The output shaft 22 of gear device 21, which is a splined shaft 23 with crowned teeth, is used to transfer the torque from the gear device 21 to the first hub device 31. The teeth of splined shaft 23 comb the teeth of splined inner surface 35. The first hub device 31, which is called inner hub as well, holds the splined shaft 23. The output shaft 22 is fixed to the first hub device 31 by means of a lock disc 27. The lock disc 27 may be split in two parts/halves (not shown here), such that the lock disc 27 can be easily mounted.

The second end 36 the first hub device 31 comprises a second front side 36a, by means of which the first hub device 31 is coupled to the second hub device 38 via a disc 42, said disc being provided as a glass fibre disc. Axially protruding from the second front side 36a in the direction of the second hub device 38, the first hub device 31 comprises a number of coarse teeth 37, eight coarse teeth in the present case (as particularly evident from Figure 7 as well). That means, that first hub device 31 is fitted with coarse teeth 37 on the outside.

The glass fibre disc 42 is fitted over the coarse teeth 37 of the first hub device 31, making it able to transfer the torque.

In the present embodiment, the glass fibre disc 42 has the shape of a spur gear having a ring-shaped base member and comprising a number of coarse teeth 43, 44, eight teeth in the present case respectively, eight teeth 43 protruding radially outwardly from the ring-shaped base member, and further comprising eight teeth 44 protruding radially inwardly from the ring-shaped base member.

Two pressure plates 45, 46 are fitted on the front and back side of the glass fibre disc 42, pressing it tightly to prevent delamination of the disc and absorb axial forces.

The coarse teeth 43 of glass fibre disc 42 are fitted on the outside of the disc in which the second hub device 38 is fitted, after this called outer hub as well. The second hub device 38 makes no contact with other metallic parts, making the coupling electrically insulated.

Second hub device 38 comprises a first front side 39a at its first end 39, said first front side 39a having a Hirth serration. By means of this Hirth serration, the generator shaft 25 is mounted to the second hub device 38. For this purpose, the front end of generator shaft 25 comprises a Hirth serration 26 as well. That means, that on the back of the second hub device 38, a Hirth serration is fitted. This ensures self-centering properties. The generator shaft 25 is also fitted with a Hirth serration 26. The serration of the second hub device 38 and the generator shaft 25 are pressed together using bolts, by making use of a transition piece for example.

As evident from the drawings, particularly from Figures 2 and 7, the second hub device 38 comprises a second end 40 having a second front side 40a, said second front side being directed towards the first hub device 31. A number of coarse teeth 41, eight coarse teeth in the present case, axially protrude from the second front side 40a in the direction of first hub device 31. Coarse teeth 41 comb with the coarse teeth 43 of glass fibre disc 42 protruding radially outwards.

As particularly evident from Figure 7, the first hub device 31, the second hub device 38 and the glass fibre disc 42 each comprise the same number of coarse teeth, eight teeth in the present case. However, the present invention is not limited to this specific number of teeth.

The coarse teeth 43, 44 of the glass fibre disc 42 comb with the coarse teeth 37 of the first hub device 31 and with the coarse teeth 41 of the second hub device 38. That means, that the respective coarse teeth come into engagement with one another. By means of the coarse teeth, rotational movements and torque gets transferred from the first hub device 31 via the glass fibre disc 42 to the second hub device 38. This goal is achieved by means of the form closure of the combing teeth which are in engagement with one another.

As can be particularly seen in Figure 7, in its assembled state, the first hub device 31 is provided radially inwardly from the second hub device 38, the glass fibre disc being provided radially between the first hub device 31 and the second hub device 38, whereby the coarse teeth 43 protruding radially outwards from the glass fibre disc 42 comb with the coarse teeth 41 of the second hub device 38 and the coarse teeth 44 of the glass fibre disc 42 protruding radially inwards from the glass fibre disc 42 comb with the coarse teeth 37 of the first hub device 31. In this case, the first hub device 31 can be defined as the inner hub device, whilst the second hub device 38 can be defined as the outer hub device.

To use the glass fibre disc 42 the torque is transferred by using large teeth on the first and the second hub device 31, 38. The glass fibre disc 42 is easy and cheap to manufacture because no mold is needed to produce the disc. A plate can be cut into the right shape with a water cutter for example. The glass fibre disc 42 can easily be removed or replaced by loosening the pressure plates 45, 46. Misalignment is compensated by the splined shaft 23 from which the teeth are crowned and by the glass fiber disc 42 that acts in a way as a damping device. The coupling is located in between the generator device 24 and the gear device 21, making it very accessible for maintenance.

The present invention can be summarized as follows. The present invention relates, among other aspects, to an interface device 30, said interface device 30 connecting an output shaft 22 of a gear device 21 to a generator shaft 25 of a generator device 24 of a drive train 20 of a wind turbine 10, whereby the interface device 30 comprises a first hub device 31, said first hub device 31 being connected to the output shaft 22 of the gear device 21, and a second hub device 38 being connected to the generator shaft 25 of the generator device 24. Output-shaft 22 is used to transfer the torque from the gear device 21 to a first hub device 31 of interface device 30. The first hub device 31 holds the output shaft 22 and is fitted with coarse teeth 37 on the outside. A glass fibre disc 42 is fitted over the teeth 37 of the first hub device 31 making it able to transfer the torque. Two pressure plates 45, 46 are fitted on the front and back side of the disc 42, pressing it tightly to prevent delamination of the disc 42 and absorb axial forces. Coarse teeth 43 are also fitted on the outside of the disc 42 in which a second hub device 38 is fitted. The second hub device 38 is fitted to the generator shaft 26 via a Hirth serration 26. This ensures self-centering properties.

List of Reference Numerals

10 Wind turbine
11 Nacelle
12 Tower
13 Rotor
14 Hub
15 Rotor blade

20 Drive Train
21 Gear Device
22 Output shaft
23 Splined shaft
24 Generator Device
25 Generator shaft
26 Serration Connection (Hirth serration)
27 Lock disc

30 Interface device
31 First hub device
32 First end
32a First front side
33 Opening
34 Inner space
35 Splined inner surface
36 Second End
36a Second front side
37 Coarse teeth
38 Second hub device
39 First end
39a First front side
40 Second end
40a Second front side
41 Coarse teeth
42 Disc (glass fibre disc)
43 Coarse teeth (protruding radially outwards)
44 Coarse teeth (protruding radially inwards)
45 Pressure plate
46 Pressure plate
,CLAIMS:WE CLAIM:

1. An interface device (30), said interface device (30) being provided for connecting an output shaft (22) of a gear device (21) to a generator shaft (25) of a generator device (24) of a drive train (20) of a wind turbine (10), whereby the interface device (30) comprises a first hub device (31), said first hub device (31) being adapted for being connected to the output shaft (22) of the gear device (21), and a second hub device (38) being adapted for being connected to the generator shaft (25) of the generator device (24), characterized by a disc (42) being provided between the first hub device (31) and the second hub device (38), said disc (42) being a glass fibre disc or a disc made of a material having the same properties like glass fibres, said disc (42) being connected to the first hub device (31) and to the second hub device (38) by means of a tooth-connection.

2. The interface device according to claim 1, characterized in that the first hub device (31) is provided as a hollow member, in particular as a hollow cylindrical member, said first hub device (31) comprising a first end (32) with a first front side (32a), said first front side (32a) having an opening (33) for receiving the output shaft (22) of the gear device (21), said hollow member particularly being adapted for receiving a spline shaft (23) of the gear device (21).

3. The interface device according to claim 1 or 2, characterized in that the first hub device (31) comprises a second end (36) with a second front side (36a), said second front side (36a) being directed towards the second hub device (38), and in that the first hub device (31) comprises a number of coarse teeth (37), in particular 5 to 10 teeth, preferably 8 teeth, said coarse teeth (37) protruding from the second front side (36a) in axial direction towards the second hub device (38), or protruding radially from the second end (36) of the first hub device (31).

4. The interface device according to anyone of claims 1 to 3, characterized in that the second hub device (38) is provided to be connected to the generator shaft (25) via a serration connection, in particular via a Hirth serration (26) connection, said second hub (38) comprising a first end (39) with a first front side (39a), said serration connection being provided at the first front side (39a).

5. The interface device according to anyone of claims 1 to 4, characterized in that the second hub device (38) comprises a second end (40) with a second front side (40a), said second front side (40a) being directed towards the first hub device (31), and in that the second hub device (38) comprises a number of coarse teeth (41), in particular 5 to 10 teeth, preferably 8 teeth, said coarse teeth (41) protruding from the second front side (40a) in axial direction towards the first hub device (31), or protruding radially from the second end (40) of the second hub device (38).

6. The interface device according to anyone of claims 1 to 5, characterized in that the disc (42) is a glass fibre disc, said glass fibre disc being made of a glass fibre material or of a glass fibre reinforce plastic material or of a glass fibre composite material.

7. The interface according to anyone of claims 1 to 6, characterized in that the disc (42) is a spur gear or has the shape of a spur gear, having a ring-shaped base member and comprising a number of coarse teeth (43), in particular 5 to 10 teeth, preferably 8 teeth, protruding radially outwardly from the ring shaped base member, and further comprising a number of coarse teeth (44), in particular 5 to 10 teeth, preferably 8 teeth, protruding radially inwardly from the ring shaped base member,

8. The interface device according to claim 7, characterized in that the coarse teeth (43, 44) of the disc (42) comb with the coarse teeth (37) of the first hub device (31) and with the coarse teeth (41) of the second hub device (38).

9. The interface device according to claim 8, characterized in that the first hub device (31) is provided radially inwardly from the second hub device (38), that the disc (42) is provided radially between the first hub device (31) and the second hub device (38), that the coarse teeth (43) protruding radially outwardly from the disc (42) comb with the coarse teeth (41) of the second hub device (38) and that the coarse teeth (44) of the disc (42) protruding radially inwardly from the disc (42) comb with the coarse teeth (37) of the first hub device (31).

10. The interface device according to anyone of claims 1 to 9, characterized in that a first pressure plate (45) is provided on a front side of the disc (42) and/or that a second pressure plate (46) is provided at the back side of the disc (42), and/or that the disc (42) is connected to the first hub device (31) and/or to the second hub device (38) by means of a glue connection.

11. A drive train (20) of a wind turbine (10), said drive train (20) comprising a gear device (21) and a generator device (24) being connected to one another by means of an interface device (30) , said interface device (30) being provided for connecting an output shaft (22) of the gear device (21) to a generator shaft (25) of the generator device (24), whereby the interface device (30) comprises a first hub device (31), said first hub device (31) being connected to the output shaft (22) of the gear device (21), and a second hub device (38), said second hub device (38) being connected to the generator shaft (25) of the generator device (24), characterized by a disc (42) being provided between the first hub device (31) and the second hub device (38), said disc (42) being a glass fibre disc or a disc made of a material having the same properties like glass fibres, said disc (42) being connected to the first hub device (31) and to the second hub device (38) by means of a tooth-connection.

12. The drive train according to claim 11, characterized in that the interface device (30) is provided according to anyone of claims 2 to 10.

13. The drive train according to claim 11 or 12, characterized in that the gear device (21) comprises an output shaft (22), said output shaft (22) being received inside the first hub device (31).

14. The drive train according to anyone of claims 11 to 13, characterized in that the generator shaft (25) is connected to the second hub device (38) by means of a serration connection, in particular by means of a Hirth serration (26) connection.

15. A wind turbine (10), said wind turbine (10) comprising a nacelle (11), a drive train (20) being mounted inside said nacelle (11) and a rotor (13), which is pivotally mounted around a rotational axis to the drive train (20), characterized in that the drive train (20) is provided according to anyone of claims 11 to 14.