DE102012213911A1 - Wind turbine for generating electric energy from kinetic energy of wind, has single bearing for supporting rotor, by which rotor is rotatably mounted on support, and generator and rotor hub, which are arranged on opposite sides of support - Google Patents

Abstract

The wind turbine (1) comprises a support (2), which is coupled to a tower. A rotor hub for supporting a rotor blade. An electric generator (6), which is designed as an external rotor. The generator on one hand and the rotor hub on the other hand are arranged on opposite sides of the support. A rotor (7) of the generator is rotatably mounted on the support or a stand (5) of the generator and is coupled to the rotor hub by an intermediate shaft (14). A single bearing (23) is provided for supporting the rotor, by which the rotor is rotatably mounted on the support or the stand.

Description

The invention relates to a wind energy plant with a carrier which can be coupled to a tower, as well as with a rotor hub for supporting at least one rotor blade, and with an electric generator, which is designed as an external rotor. The generator on the one hand and the rotor hub on the other hand are arranged on opposite sides of the carrier, and a rotor of the generator is coupled via an intermediate shaft with the rotor hub. The rotor is rotatably mounted on the carrier and / or a stator of the generator.

Wind turbines (also known under the name "wind turbines") are already known from the prior art in a variety of configurations. Such systems serve to provide electrical energy from the kinetic energy of the wind. A wind turbine includes a tower, which serves as a supporting structure for the entire system. On the tower, the essential components of the system are arranged, namely in particular an electric generator, as well as a rotor with rotor blades. While the rotor serves to convert the kinetic energy of the wind into a rotational energy, it is the task of the generator to convert the rotational energy into electrical energy.

There are already known systems in which the generator and the rotor are arranged on the same side of the tower or the generator between the rotor on the one hand and the tower on the other hand and thus on the windward "windward side" of the system. This arrangement has particular advantages in terms of the total weight, so that overall a weight-optimized construction can be provided. However, such an arrangement of the generator is also associated with the problem that measures must be taken to ensure reliable decoupling occurring on the rotor bending moments of the generator. The bending moments are usually caused by wind forces that occur at the rotor hub due to different wind conditions on the rotor blades. Because the rotor blades are relatively long and the difference in height at which the different rotor blades are located is correspondingly large, in each case different wind speeds and consequently also different wind forces occur at the rotor blades. These then cause a bending movement of the rotor hub, which in some systems, a change in the air gap, ie the radial distance between the rotor on the one hand and the stator of the generator on the other hand, the result. The transmission of the bending moments to the generator and thus the change in the air gap must be prevented by appropriate design of the system and in particular by appropriate storage of the rotor hub and the generator.

Due to the aforementioned disadvantages of the "windward construction", the interest in this case applies to a wind power plant in which the rotor with rotor blades on the one hand and the generator on the other hand are arranged on opposite sides of the tower. In such a construction, the generator is therefore on the leeward lee side of the plant. This arrangement is for example from the document DE 10 2011 008 029 A1 known. The "Lee construction" in particular has the advantage over the "windward construction" that no or significantly lower bending moments can occur on the rotor of the generator. Namely, the intermediate shaft between the generator and the rotor can be formed from two partial shafts, which can be coupled to one another via an interposed clutch, in particular gearless, as proposed in said document. The coupling can be constructed so that it can transmit only rotational movements about the axis of the rotor to the generator, while bending movements of the rotor are not or only to a very small extent transmitted to the generator. Another advantage of the arrangement of the generator on the "lee side" of the system is that the generator alone can be mounted or dismounted independently of the wind blades. This simplifies the assembly or disassembly of the generator - for example, when replacing the generator - considerably. Yet another advantage of the "Lee-Generator" is seen in a better weight distribution of the masses of the carrier, the rotor and the generator. This in turn leads to a lower material stress and consequently to a longer life of the components.

However, the arrangement of the generator on the "lee side" has certain disadvantages: With such a construction, one must expect a relatively high total weight or a high tower head mass, because an additional intermediate shaft is used to connect the rotor on the one hand to the generator on the other hand got to. However, the decisive disadvantage lies in the number of bearings to be used, namely on the one hand for the generator and on the other hand for the rotor of the system, as well as additionally for the intermediate shaft. As in particular in the figures of the document DE 10 2011 008 029 A1 it can be seen, two separate bearings are required for the storage of the rotor of the generator in such systems. Such a solution is on the one hand particularly expensive, because expensive large storage must be used, and additionally affects the overall weight of the system.

It is an object of the invention to provide a solution as the total weight of a wind turbine of the type mentioned can be reduced compared to the prior art.

This object is achieved by a wind turbine with the features of claim 1. Advantageous embodiments of the wind turbine are the subject of the dependent claims, the description and the figures.

A weight optimized wind turbine has a carrier which can be coupled to a tower. The system also has a rotor hub for supporting at least one rotor blade and an electric generator, which is designed as an external rotor. The generator on the one hand and the rotor hub on the other hand are arranged on opposite sides of the carrier. In other words, the generator is thus arranged in the assembled state of the system on a side opposite the rotor of the tower, namely on the "lee side". A rotor of the generator is coupled via an intermediate shaft with the rotor hub. The rotor is further rotatably mounted on the carrier and / or on a stator of the generator. According to the invention it is provided that for the storage of the rotor, the wind turbine exclusively has a single bearing, via which the rotor is rotatably mounted on the carrier and / or the stator.

The effect according to the invention is therefore achieved by reducing the number of bearings required for bearing the rotor to a minimum and by supporting the rotor via a single bearing on the carrier and / or the stator directly or over a region of the intermediate shaft. The wind turbine according to the invention thus has the significant advantage that the total weight of the system or the tower head mass is significantly reduced compared to the prior art, because an additional bearing is known to be a relatively large and heavy component. Another advantage is the provision of a cost-reduced system in which at least one bearing for the runner is saved in comparison to the prior art. Because such bearings, as used in wind turbines are relatively expensive, thus a total cost can be saved in the provision of the wind turbine. In particular, the wind turbine on the side of the generator - ie on the lee side - a single bearing for the bearing of the rotor and the intermediate shaft.

In particular, it can be provided that the intermediate shaft is formed from at least two partial waves, which are coupled to one another via a clutch - in particular gearless. The one partial wave is assigned to the rotor of the generator, while the other partial wave is assigned to the rotor of the system. In particular, this coupling is designed to transmit predominantly rotational movements about the axis of rotation of the rotor on the rotor of the generator, while bending moments of the rotor are preferably not or only to a very small extent transmitted to the rotor.

Preferably, the rotor has an end wall facing away from the carrier and forming an outer axial end of the rotor, which is non-rotatably connected to the intermediate shaft. The rotor is thus connected in this embodiment via its outer axial wall to the intermediate shaft and preferably also to the bearing. This embodiment allows a stable and well-durable or stable support of the rotor and also a common storage of the rotor and the intermediate shaft on the single bearing.

In one embodiment, it is provided that the rotor is mounted on the single bearing via the axial end wall-directly or via the intermediate shaft. Thus, the runner is connected via its end face remote from the carrier - possibly via a small axial region of the intermediate shaft - connected to the bearing and stored. This embodiment allows on the one hand a common mounting of the rotor and the intermediate shaft on the single bearing and on the other hand ensures a particularly stable support of the rotor on the bearing or the associated bearing ring.

Preferably, the stand is axially connected to the carrier. The stand may have an axial indentation or recess on its axial end face facing away from the carrier. This recess may have a depth in the axial direction which is between half the axial length and the entire axial length of the generator. This means that the recess in the axial direction may have a depth which is greater than half the axial length of the stator. By providing such a recess on the axial end face of the stator, the weight of the wind turbine can be further optimized because the mass of the laminated core of the stator is reduced overall. It also results in a significant material savings.

It proves to be particularly advantageous if the side facing away from the carrier end wall of the rotor extends axially into the axial recess of the stator. Preferably, the outer end wall of the rotor is funnel-shaped. It preferably extends substantially all the way to an axial end or to the bottom of the indentation, on which this outer wall is preferably rotatably coupled to the intermediate shaft. This embodiment, in which the outer end wall of the rotor extends into the axial indentation, has the particular advantage that the length of the intermediate shaft can be significantly reduced compared to designs in which the outer wall is flat and perpendicular to the axis of rotation , The reduction of the length of the intermediate shaft in turn leads to a saving of material, as well as to a further optimization of the total weight of the plant.

The only bearing transmits so the complete radial forces between rotor and carrier in a normal operation. Beyond normal operation, however, an air gap (radial distance) between the rotor and the stator may be reduced due to, for example, relatively large radial forces and bending moments. In order always to be able to comply with at least a predetermined minimum air gap between the rotor and the stator, the wind turbine can optionally have a support device, via which a wall facing the carrier and an axial end of the rotor forming wall of the rotor at greater forces to maintain the minimum air gap radial can be supported on the carrier for a short time. Thus, an excessive reduction of the air gap or even a touch of the rotor and the stator can be prevented.

In order to optimize the overall weight, the support device may comprise, for example, at least two support elements distributed in the circumferential direction on the support, on which the wall of the rotor facing the support can optionally be supported in the radial direction. These support elements may each have a roller which is rotatable about an axis extending parallel to the axis of rotation of the rotor. The support means may further comprise on the side of the rotor a circumferential rail, which are supported on the respective circumference of the rollers and thus may optionally set the rollers in a rotational movement. A radial distance between the rail and the support elements is preferably less than the air gap between the rotor and the stator.

In a further embodiment it can be provided that the single bearing is designed as a rolling bearing. In order to allow a particularly rigid bearing of the rotor, in particular a so-called moment bearing or a double-row bearing is used, so that the rotor of the generator is mounted on the carrier via this double-row torque bearing. The bearing can be, for example, a deep groove ball bearing, a cylindrical roller bearing or a tapered roller bearing. The double-row bearing allows a particularly secure and rigid bearing of the rotor on the carrier.

Further features of the invention will become apparent from the claims, the figures and the description of the figures. All the features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively indicated combination but also in other combinations or alone.

The invention will be explained below with reference to a preferred embodiment, as well as with reference to the accompanying drawings. It should be emphasized that the embodiment described below represents a preferred embodiment of the invention and the invention is thus not limited to this exemplary embodiment. Show it:

1 a schematic sectional view through a portion of a wind turbine according to an embodiment of the invention;

2 in a schematic and perspective view of the area of the wind turbine; and

3 a schematic representation of a side view of the wind turbine from the front side of a generator.

An in 1 in a schematic representation of the wind turbine 1 has a carrier 2 on, which with its attachment side 3 ( 2 ) is connected to a tower not shown in the figures. The carrier 2 thus represents a tower head, which - as in 2 is shown - for example, via a flange 4 can be connected to the tower. The carrier 2 can then be mounted rotatably on the tower in the horizontal direction about a substantially vertical axis of rotation.

With further reference to 1 is the carrier 2 with a stand 5 a generator 6 axially connected. The generator 6 is designed as an external rotor. He includes a runner 7 , which outside the stand 5 encloses. This means that the runner 7 around the stand 5 is rotatably mounted around. On the stand 5 is an electric stator winding 8th with winding heads 9 deployed while the runner 7 For example, in the FIG not wearing permanent magnets. In one embodiment, the generator is 6 thus a permanent magnet synchronous machine.

The stand 5 is on the one hand with the carrier 2 directly connected. On the other hand, the stand points 5 at his from the carrier 2 remote outer axial end face 10 an axial indentation 11 on which an axial recess in the front side 10 represents. This indentation 11 has a depth in the axial direction, which in particular is greater than half the axial length of the stator 5 is.

The indentation 11 So in other words forms an axial recess in the front page 10 of the stand 5 ,

The runner 7 has a coat 12 which is at a radial distance from the stator 5 is arranged and a - seen in the radial direction - outer wall of the rotor 7 represents. The coat 12 is encircling the stand 5 arranged around. It is especially the coat 12 which carries the above-mentioned permanent magnets.

On the of the carrier 2 facing away from the axial side of the rotor 7 an axial end wall 13 , which in the axial direction, the outer end face of the rotor 7 forms. This end wall 13 extends in the axial direction in the recess 11 into it and extends to the bottom or to the axial end of the indentation 11 on which the end wall 13 with an intermediate shaft 14 rotatably connected. The connection is made for example via a flange 15 , The front wall 13 is executed in a funnel shape, the shape of the end wall 13 to the geometric shape of the indentation 11 in the stand 5 is adjusted. An axial distance 16 between a first axial end 17 the front wall 13 on the one hand and a second axial end 18 same end wall 13 - So in particular the flange 15 - On the other hand, preferably equal to or greater than half the axial length of the rotor 7 , Thus, overall results in a significant weight reduction.

The front wall 13 also provides a sort of shield of the runner 7 which the runner is about 7 radially on a bearing 23 is stored. The runner 7 or his front wall 13 is about the camp 23 on the carrier 2 rotatably mounted. The front wall 13 can thereby directly - for example via a flange, not shown in the FIG - with the camp 23 be connected. Alternatively, the storage of the runner 7 - as in 1 represented - over an axial region of the intermediate shaft 14 done so that the end wall 13 with the intermediate shaft 14 and same wave 14 again with the camp 23 are connected.

It is on the lee side of the plant 1 or on the side of the generator 6 only one warehouse 23 for the storage of the runner 7 and the intermediate shaft 14 on the carrier 2 or the stand 5 used. This camp 23 In principle, it can be any roller bearing and in one embodiment, for example, a double-row tapered roller bearing - a so-called moment bearing. Thus, a particularly stiff storage of the rotor 7 on the carrier 2 ensured because the pressure over a relatively large axial length of the bearing 23 can be distributed.

On the carrier 2 facing axial side in turn, the rotor 7 another wall 19 on which perpendicular to the mantle 12 and perpendicular to a rotation axis 20 the intermediate shaft 14 is arranged. This wall 19 Can via an optional support device 21 on the carrier 2 be radially supported when larger radial forces and bending moments occur. This support device 21 on the one hand, one on the wall 19 arranged on the other hand, a plurality of supporting elements on the support 2 can be arranged distributed in the circumferential direction, which are then at a radial distance from the rail. The support elements may have respective rollers on which the rail of the wall 19 is briefly supported when bending moments occur and in this case the roles also possibly put into a rotary motion. The said support elements may also be resilient, so that the rollers via respective spring elements with the carrier 2 are connected. The support device 21 serves to maintain a predetermined minimum radial air gap between the rotor 7 and the stand 5 , In particular, it does not serve to transmit radial forces in normal operation, in which the actual air gap is greater than the predetermined minimum air gap. In normal operation, the radial forces between runners 7 and stand 5 completely over the only camp 23 transfer. Only when the actual air gap reaches the predetermined minimum value, the rail is supported radially on at least one of the rollers and the minimum air gap does not fall below.

The carrier 2 has an axial passage opening 22 on, through which the intermediate shaft 14 extends through to the front wall 13 of the runner 7 to be connected. Inside the vehicle 2 is the warehouse 23 , The carrier 2 encloses an axial region of the intermediate shaft 14 outer circumference.

On the other side is the intermediate shaft 14 - Optionally via a clutch - with a not shown in the FIG rotor of the wind turbine 1 connected. This rotor then carries rotor blades, which from the kinetic energy of the wind, a rotational energy at the intermediate shaft 14 generate, which via the intermediate shaft 14 to the runner 7 is transmitted. By said coupling, the bending moments can almost completely from the rotor 7 be decoupled.

2 now shows a perspective view of the wind turbine 1 , How out 2 shows, is the carrier 2 a curved hollow body and has on its from the generator 6 opposite side another passage opening 24 through which the intermediate shaft 14 from the carrier 2 protruding towards the rotor.

Another illustration of the wind turbine 1 is in 3 shown. Here is the wind turbine 1 represented by its axial windward end, which through the wall 13 of the runner 7 is formed.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102011008029 A1 [0004, 0005]

Claims (8)

Wind energy plant ( 1 ) with: - a carrier ( 2 ), which can be coupled to a tower, - a rotor hub for supporting at least one rotor blade and - an electric generator ( 6 ), which is designed as an external rotor, - wherein the generator ( 6 On the one hand and the rotor hub on the other hand on opposite sides of the carrier ( 2 ) and wherein a runner ( 7 ) of the generator ( 6 ) on the carrier ( 2 ) and / or a stand ( 5 ) of the generator ( 6 ) is rotatably mounted and via an intermediate shaft ( 14 ) is coupled to the rotor hub, characterized in that for the storage of the rotor ( 7 ) the wind turbine ( 1 ) only one warehouse ( 23 ) over which the runner ( 7 ) on the carrier ( 2 ) and / or the stand ( 5 ) is rotatably mounted. Wind energy plant ( 1 ) according to claim 1, characterized in that the runner ( 7 ) one of the carrier ( 2 ) and an axial end of the rotor ( 7 ) forming end wall ( 13 ), which with the intermediate shaft ( 14 ) is rotatably connected. Wind energy plant ( 1 ) according to claim 2, characterized in that over the end wall ( 13 ) the runner ( 7 ) directly or via the intermediate shaft ( 14 ) at the warehouse ( 23 ) is stored. Wind energy plant ( 1 ) according to one of the preceding claims, characterized in that the stand ( 5 ) of the generator ( 6 ) on one of the carrier ( 2 ) facing away from axial end face ( 10 ) an axial indentation ( 11 ) having. Wind energy plant ( 1 ) according to claim 2 or 3 and claim 4, characterized in that that of the carrier ( 2 ) facing away from the end wall ( 13 ) of the runner ( 7 ) in the axial recess ( 11 ) extends axially into it. Wind energy plant ( 1 ) according to one of the preceding claims, characterized in that the wind energy plant ( 1 ) a supporting device ( 21 ), over which a carrier ( 2 ) facing wall ( 19 ) of the runner ( 7 ) for maintaining a predetermined minimum air gap between the runner ( 7 ) and the stand ( 5 ) radially on the carrier ( 2 ) is supportable. Wind energy plant ( 1 ) according to claim 6, characterized in that the supporting device ( 21 ) at least two in the circumferential direction on the carrier ( 2 ) arranged distributed support elements, in particular each with a roller, on which the the carrier ( 2 ) facing wall ( 19 ) of the runner ( 7 ) Can be supported in the radial direction. Wind energy plant ( 1 ) according to one of the preceding claims, characterized in that the only bearing ( 23 ) is designed as a rolling bearing, in particular as a moment bearing.

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