DE102010064637B3 - Method for maintaining a wind energy installation, intermediate piece and method for using at least one such intermediate piece - Google Patents

Abstract

A method for maintaining a wind turbine, in which at least one rotor blade (200) is attached to a hub (100) of the wind turbine in an adjustable angle of attack by means of a slewing ring (110, 120) during operation of the wind turbine, and a movable slewing ring part (120) with the hub (100) ) is rotatable and fixedly connected to a rotor blade flange (210) of the rotor blade (200) by means of a plurality of screw bolts, the method comprising the following steps: Rotor blades (200) on the hub (100) at least one intermediate piece (500, 550) is attached to the hub (100) and to the rotor blade (200), - rotating the movable turntable part (120) with respect to the rotor blade flange (210), and - Fastening the rotor blade (200) to the turntable (110, 120).

Description

The invention relates to wind turbines with a rotor blade adjustment (also called pitch adjustment or pitch adjustment). Such wind turbines have a rotor blade bearing - also called a slewing ring - for their adjustable rotor blade. The invention relates in particular to the maintenance of such wind turbines.

Wind energy plants typically have a rotor with a hub to which several rotor blades are usually attached. In order to be able to change the angle of attack of a respective rotor blade, a rotor blade adjustment is usually provided. This can have a slewing ring, the movable part of which is connected to the hub via a pivot bearing and is thus rotatable about a longitudinal axis of the rotor blade with respect to the hub. The respective rotor blade is fastened to the movable part and is thus also rotatable about its longitudinal axis and adjustable in angle with respect to the hub.

Rotary assemblies of this type used in wind turbines usually form a unit with the rotary bearing and, as a unit, usually have an inner and an outer ring, as well as rolling elements, spacers or a cage. The freely rotatable part of the unit, which is referred to below as the movable turntable part and which is connected to the rotor blade, is adjusted here. The counterpart is rigidly connected to the hub. The adjustment usually takes place via a toothing of the slewing ring with the aid of a gear-motor combination.

On wind turbines with electrical rotor blade adjustment, increased wear of the rotor blade bearing toothing, i.e. the toothing of the turntable, can occur in the range of about 0 ° -5 ° rotor blade pitch angle (rotor blade position). This is due to the rotor blade adjustment in the upper load range of the wind turbine.

The range of use of the toothing is usually 90 ° in wind turbines with regulated rotor blade adjustment. The rotor blades are moved in the range from 0 ° to 90 °. The range 0 ° -5 ° is regarded as the working range. In this area there is the greatest amount of wear and tear. In the work area, the applied lubricant is displaced by a permanent movement of the drive, so that increased abrasion of the affected area sets in. When the wear limit is reached, it is necessary to rotate the position of the rotor blade bearing relative to the rotor blade so that teeth of the toothing on the slewing ring that have not yet been worn come into engagement with the drive.

Two methods are currently used to implement the rotor blade bearing rotation. In the first method, the rotor of the wind energy installation is dismantled. The rotor blades are dismantled individually with two truck-mounted cranes, the movable turntable part is moved and the rotor blade is reassembled. In the second method, the rotor blade is dismantled with the rotor installed using two cranes or a crane - using a frame that maintains the balance of the rotor blade, the movable turntable part is moved and the rotor blade is reassembled. In both processes, the movable turntable part is moved into the area that has not been used up to this point in time.

The font DE 103 03 555 B4 shows a method for the crane-free assembly or dismantling of a rotor blade of a wind power plant on a rotor blade connection on a hub of a rotor of the wind power plant, with at least one rope being clamped between a part in the hub area of the wind power plant and the bottom area of the wind power plant, which takes on a continuous winch, which in turn is detachably connected to the hub-side connection of the rotor blade, so that when the feed line is in operation, it is moved up or down along the cable together with the rotor blade.

An alternative, preferably simpler, procedure for maintaining wind turbines is desirable.

According to a first aspect, the invention relates to a method for maintaining a wind turbine, in which at least one rotor blade is attached to a hub of the wind turbine in an adjustable angle of attack by means of a turntable during operation of the wind turbine, and a movable turntable part rotatable with the hub and with a rotor blade flange of the Rotor blade is firmly connected by means of a plurality of screw bolts.

• - Hängendes Befestigen des Rotorblatts an der Nabe, wobei zum hängenden Befestigen des Rotorblatts an der Nabe mindestens ein Zwischenstück an der Nabe und an dem Rotorblatt befestigt wird,
• - Drehen des beweglichen Drehkranzteils bezüglich des Rotorblattflansches, und
• - Befestigen des Rotorblatts an dem Drehkranz.

The process consists of the following steps:

• - Suspended fastening of the rotor blade to the hub, with at least one intermediate piece being fastened to the hub and to the rotor blade for the suspended fastening of the rotor blade to the hub,
• - Rotating the movable turntable part with respect to the rotor blade flange, and
• - Attaching the rotor blade to the turntable.

The method according to the first aspect of the invention makes it possible to rotate the turntable without the need for a truck crane or a similar heavy device.

The method can in principle be used in wind energy installations which have a horizontal axis of rotation. Such wind energy installations usually have a tower, a nacelle mounted on the tower and a hub mounted on one side of the nacelle. In the nacelle there is usually a generator, a brake and, if necessary, a gearbox. Rotor blades are attached to the hub, with typical wind turbines having two or three rotor blades. However, none of the aspects of the invention are restricted to wind energy installations with a specific number of rotor blades. Rather, the invention can in principle be used in wind energy installations with any number of rotor blades.

During the operation of a wind energy installation to which the method according to the first aspect of the invention can be applied, at least one rotor blade is attached to the hub of the wind energy installation in an adjustable angle of attack by means of a slewing ring. The slewing ring typically has an inner ring and an outer ring. It can either be designed so that the outer ring is stationary and the inner ring is rotatable, or that the inner ring is stationary and the outer ring is rotatable. Depending on whether the outer ring or the inner ring can be rotated, the outer ring or the inner ring is referred to as a movable turntable part. To rotate the turntable means to rotate the movable turntable part relative to the other part of the turntable and to the hub. An electric motor, which is provided with a small gear wheel and engages in a gear ring on the turntable, is usually used to rotate the slewing ring.

The rotor blade has a rotor blade flange which is used for fastening to the movable turntable part. For this purpose, a large number of screw bolts are usually used, which connect the movable turntable part to the rotor blade flange. For this purpose, the rotor blade flange typically has threaded bores for receiving the screw bolts.

According to the first aspect, after the lowering of the rotor blade, at least one intermediate piece for holding the rotor blade is attached to the hub and to the rotor blade. A suitable intermediate piece is described, for example, further below in connection with the second aspect of the invention. The intermediate piece should be attached to both the rotor blade and the hub in such a way that it is able to hold the rotor blade. This can be done in a variety of ways, for example by screwing, hanging, pushing in, etc.

Several intermediate pieces are preferably used. By using two intermediate pieces, the degrees of freedom of movement of the rotor blade can be restricted in a state in which the rotor blade is only held by the intermediate pieces. The use of three or more intermediate pieces ensures that the rotor blade no longer has any degrees of freedom of movement in a state in which it is only held by the intermediate pieces. The advantages to be achieved with it are identical to those which can be achieved by using several threaded rods.

Alternatively, an intermediate piece can also have several fastening points. Such an intermediate piece can be connectable to the rotor blade flange at several points, for example with several screw bolts, and / or it can be connectable to the hub at several points, for example with several screw bolts.

Even when using several intermediate pieces, and in particular when using only one intermediate piece, the intermediate pieces should preferably be designed in such a way that a single intermediate piece is able to hold the rotor blade on its own. This increases security.

In one embodiment, for example when an intermediate piece according to the second aspect of the invention is used, the intermediate piece is fastened to the hub and to the rotor blade flange with one screw bolt each. The intermediate piece serves to compensate for the different pitch circle diameters of the rotor blade flange and the hub flange. In other words, the intermediate piece serves as a pitch circle adapter. Alternatively, the intermediate piece can also be fastened only to the rotor blade or only to the hub with a screw bolt, the intermediate piece then being fastened to the respective other element in a different way.

The intermediate piece is typically attached by industrial climbers. Alternatively, however, it is also conceivable that an intermediate piece is attached with the aid of a cable winch, a robot or some other device.

The method according to the first aspect of the invention, which comprises the method feature of holding the rotor blade on a further element, for example on an intermediate piece or on a rope, achieves a hanging fastening of the rotor blade on the hub. For this purpose, after the at least one intermediate piece has been attached, all screwed-in threaded rods are unscrewed again. The rotor blade is thus only supported by the at least one intermediate piece held on the hub. In this state, the rotor blade is attached to the hub in a suspended manner.

The advantage of continuing the method up to the hanging fastening of the rotor blade to the hub is that, after the method has been completed, the movable turntable part can be rotated independently of the rotor blade. This is possible because the hanging attachment of the rotor blade to the hub means that there is no longer a fixed connection between the movable turntable part and the rotor blade. When the rotor blade is suspended from the hub, the rotor blade, which is normally attached to the movable turntable part, is released from the turntable and otherwise suspended from the hub by means of the at least one intermediate piece. Free rotation of the movable turntable part is thus possible.

In the step of rotating the movable turntable part with respect to the rotor blade flange, the turntable is preferably rotated at least so far that a gear of a drive motor, which ensures the angular adjustability, engages at a point of a gear rim in the working area after the turntable has been rotated, which has so far only been used little and in particular is not worn out yet. The turntable is preferably rotated by at least 10 °, particularly preferably by at least 15 ° or very particularly preferably by at least 100 °. At least the slewing ring should not be rotated by 0 °, 360 ° or an integral multiple thereof. Likewise, the turntable should not be rotated into a position in which the gear wheel of the drive motor would come into engagement in the working area with a point on the gear rim which is already worn.

The step of rotating the movable turntable part with respect to the rotor blade flange can be carried out in such a way that the movable turntable part is rotated with respect to the hub while the rotor blade flange is not rotated. Alternatively, however, it can also be designed in such a way that the rotor blade flange is rotated while the movable turntable part is not rotated. This is possible, for example, when the rotor blade is fastened while hanging from ropes. A combination of the two versions is also possible.

• - Einschrauben mindestens einer Gewindestange, welche mit einem Hydraulikzylinder verbunden ist, in eine Gewindebohrung in dem Rotorblattflansch,
• - Entfernen von Zwischenstücken, so dass das Rotorblatt nur noch durch eine oder mehrere Gewindestangen gehalten wird,
• - Hochziehen des Rotorblatts mittels des mindestens einen Hydraulikzylinders,
• - Befestigen des Rotorblatts an dem Drehkranz durch Einschrauben einer Vielzahl von Schraubbolzen.

The step of fastening the rotor blade preferably comprises the following steps:

• - screwing at least one threaded rod, which is connected to a hydraulic cylinder, into a threaded hole in the rotor blade flange,
• - Removal of intermediate pieces so that the rotor blade is only held by one or more threaded rods,
• - Pulling up the rotor blade by means of the at least one hydraulic cylinder,
• - Fastening the rotor blade to the turntable by screwing in a large number of screw bolts.

This essentially reverses the loosening of a rotor blade.

The step of screwing in at least one threaded rod, which is connected to a lifting means, creates a fixed connection between the threaded rod and the rotor blade. A plurality of, for example two or particularly preferably three or four, threaded rods are preferably used for this purpose. In this way, the rotor blade can be held on the threaded rods, as a result of which the intermediate pieces can be removed without the rotor blade falling down.

In the step of removing the intermediate pieces, the ropes or the guide rails, the direct connection between the rotor blade and the hub, which is mediated by the intermediate pieces, is canceled. From now on, the rotor blade only hangs on one or more threaded rods. This also makes it possible for the rotor blade to be subsequently pulled up by means of the at least one lifting means.

To pull up the rotor blade by means of the at least one lifting means in the form of a hydraulic cylinder, a pressure in a pressure chamber of the hydraulic cylinder is usually increased so that the threaded rod exerts an upward force on the rotor blade which is greater than the portion of the acting on the respective threaded rod Gravity of the rotor blade. This lifts the rotor blade and returns it to the position in which the rotor blade flange rests on the slewing ring.

Through the step of fastening the rotor blade to the turntable by screwing in a plurality of screw bolts, a firm connection between the rotor blade and the turntable is again established. The rotor blade can thus be used again to drive the wind energy installation. The rotor blade flange is preferably screwed onto the movable turntable part.

After the step of fastening the rotor blade to the turntable, a further method step is preferably carried out in which the threaded rods are removed. The threaded rods can thus be used, for example, to carry out the method according to the invention on a different rotor blade.

• - Ausrichten des Rotorblatts in eine von der Nabe aus gesehen wenigstens annähernd senkrecht nach unten weisende Position,
• - Einschrauben mindestens einer Gewindestange in eine Gewindebohrung in dem Rotorblattflansch,
• - Halten des Rotorblatts mittels eines mit der wenigstens einen Gewindestange verbundenen Hubmittels in einer Position, in welcher der Rotorblattflansch an dem Drehkranz anliegt,
• - Lösen aller Schraubbolzen, und
• - Absenken des Rotorblatts mittels des Hubmittels.

According to some illustrative embodiments of the method according to the first aspect, the method of the first aspect can comprise the following steps before the rotor blade is attached to the hub in a hanging manner:

• - Alignment of the rotor blade in a position that, when viewed from the hub, points at least approximately vertically downwards,
• - screwing at least one threaded rod into a threaded hole in the rotor blade flange,
• - Holding the rotor blade by means of a lifting means connected to the at least one threaded rod in a position in which the rotor blade flange rests on the turntable,
• - Loosen all bolts, and
• - Lowering the rotor blade by means of the lifting means.

The method according to these illustrative embodiments enables the rotor blade to be released as a prerequisite for releasing the slewing ring without the aid of a truck-mounted crane or similar heavy equipment.

The lifting means is here preferably a hydraulic cylinder.

In the step of aligning the rotor blade in a position that points at least approximately vertically downward from the hub, the respective rotor blade is brought into a position in which, with one end remote from the hub, it faces in the direction of gravity, i.e. in the direction of the center of the earth , shows, so that essentially no bending forces act on the rotor blade flange.

In the step of screwing in at least one threaded rod, the fastening of the rotor blade already secured immediately beforehand by screw bolts is expanded by an additional fastening by the threaded rod. This means that before this step the rotor blade was only fastened through all if separate threaded holes for threaded rods - or some screw bolts, whereas after this step it is fastened both by screw bolts and by the threaded rod. This will normally not be associated with an immediate movement of the rotor blade. However, this step creates the prerequisite for all of the bolts to be removed later.

The respective threaded rod is preferably connected to a respective lifting means in such a way that it can exert a holding force on the rotor blade. This is typically achieved in that the lifting means is connected sufficiently firmly to the threaded rod and itself either rests on the turntable or another supporting part, or is suspended from a suitable supporting part within the hub. By screwing the threaded rod into a threaded hole in the rotor blade flange, a fixed connection is also created between the threaded rod and the rotor blade, so that the threaded rod can hold the rotor blade. The threaded rod and the lifting means are preferably designed in such a way that when the lifting means is appropriately fastened, the threaded rod alone is able to hold the rotor blade.

In the step of holding the rotor blade by means of the lifting means in a position in which the rotor blade flange rests on the turntable, the hydraulic cylinder is, as the preferred lifting means, placed in a pressure state in which the threaded rod exerts an upward force on the rotor blade, which the on the respective threaded rod corresponds to or exceeds the force of gravity. Hydraulic cylinders usually have a piston and two pressure chambers laterally adjoining the piston. For the purpose of the method according to the first aspect of the invention, a control of the pressure in a chamber is basically sufficient. Typically that chamber will be used for which it is true that an increase in pressure in this chamber leads to an upward force of the threaded rod on the rotor blade. For example, if the threaded rod is an extension of a piston rod of the hydraulic cylinder and the hydraulic cylinder rests on the turntable with the piston rod pointing downwards, the pressure in the lower chamber of the hydraulic cylinder is typically controlled for carrying out the method according to the first aspect of the invention. To hold the rotor blade in a position in which the rotor blade flange rests against the turntable, the pressure in this chamber will then be increased. This can be done, for example, by using a hydraulic pump.

It should be mentioned that the pressurization of the hydraulic cylinder described is not mandatory. Likewise, in the step of holding the rotor blade by means of the hydraulic cylinder in a position in which the rotor blade flange rests against the turntable, a pressure chamber of the hydraulic cylinder can be provided with a particularly low pressure, provided that the hydraulic fluid used has a sufficiently low vapor pressure. It should be a chamber in which a reduction in the pressure in this chamber leads to an upward force on the rotor blade. During the step of lowering the rotor blade, the pressure in this chamber should then be increased accordingly. Alternatively, you can do both Pressure chambers of the hydraulic cylinder are controlled in parallel and used to carry out the method.

When the rotor blade is held by means of the hydraulic cylinder in a position in which the rotor blade flange rests against the turntable, all screw bolts with which the rotor blade flange and the movable turntable part are connected are loosened. The rotor blade does not move in spite of the loosening of all screw bolts because it is held in its position by means of the hydraulic cylinder. The threaded rod and the hydraulic cylinder thus now fulfill the function of the screw bolts before they are loosened.

The step of lowering the rotor blade by means of the hydraulic cylinder is typically initiated by lowering the pressure in a pressure chamber of the hydraulic cylinder, which was increased in the step of holding the rotor blade. In this case, the pressure is suitably reduced in such a way that the force exerted on the rotor blade by the threaded rod can no longer fully compensate for the force of gravity of the rotor blade. This causes the rotor blade to move downwards.

In one embodiment of the method according to the first aspect of the invention, before the threaded rod is screwed in, a screw bolt screwed into the threaded bore is unscrewed and removed. This variant of the method is used when the threaded rod is to be screwed into a threaded hole in the rotor blade flange into which a screw bolt for connecting the rotor blade flange to the movable turntable part was previously screwed. However, this is not mandatory. Alternatively, for example, the threaded rod can be screwed into a bore in the rotor blade flange which is specially provided for this purpose or which is not provided with a screw bolt when the wind turbine is in operation, for example because the necessary strength of the connection between the rotor blade and the slewing ring can also be achieved without a screw bolt is achieved in this hole.

At least two threaded rods, each connected to a lifting means, are preferably screwed into a threaded hole in the rotor blade flange. The fastening of the rotor blade to the turntable is thus improved, in particular the rotor blade is then fastened to a further fastening point, as a result of which its degrees of freedom of movement are restricted.

It is even more preferred to screw three threaded rods, each connected to a lifting means, into a threaded hole in the rotor blade flange. A plane of the rotor blade flange can thus be clearly defined so that the rotor blade flange and thus also the rotor blade no longer have any degrees of freedom of movement. By reducing the degree of freedom of movement of the rotor blade, it can be prevented that, for example, when wind occurs, which leads to a bending force on the rotor blade flange, too great a bending force is exerted on the individual threaded rods and the lifting means, which leads to the threaded rod tearing off and, in the worst case, falling down of the rotor blade. It is therefore particularly preferred to use either three or four threaded rods, each of which is connected to a hydraulic cylinder. However, any other number of threaded rods can also be used.

Even when a plurality of threaded rods are used, each of which is connected to a hydraulic cylinder, it is preferred that each of the threaded rods and the associated lifting means are designed to hold the rotor blade on its own. If, for example, a material failure occurs in one of the threaded rods, the rotor blade can still be held on the other threaded rods.

According to a second aspect, the invention relates to an intermediate piece for hanging a rotor blade on a hub of a wind turbine, which has a flat top side and a flat bottom side parallel thereto, both the top side and the bottom side being provided with through holes.

The through holes are accessible from a space between the top and bottom, so that a screw bolt can be inserted into the through hole and screwed into an adjacent threaded hole.

The respective through hole in the bottom is offset from the corresponding through hole in the top.

The intermediate piece according to the second aspect of the invention is particularly suitable for performing a method according to the first aspect of the invention, which is expanded to include the step of attaching an intermediate piece.

With the help of the intermediate piece, the rotor blade can be suspended from the hub. The intermediate piece can be installed by industrial climbers, for example. This is much easier than using a truck-mounted crane or similar heavy equipment.

The intermediate piece is preferably made of a metal such as aluminum or steel. Depending on the material, this typically has a mass of around 20 to 40 kilograms in order to achieve the necessary load-bearing capacity. This makes it possible for such an intermediate piece to be brought into the working area at hub height with an electric cable winch inside the tower or with a hub crane. This also avoids the need for a truck crane or a similar heavy device.

The design of the intermediate piece can be different. A typical function of the intermediate piece is that the different pitch circle diameters of the hub flange, to which the fixed part of the slewing ring is attached, and the rotor blade flange, which is connected to the moving part of the slewing ring during operation, are bridged. In addition, the through holes should be large enough so that sufficiently thick bolts can be inserted through to hold the rotor blade on the hub. However, the through holes should not only be accessible in order to be able to push through the screw bolts, but should also be sufficiently accessible to allow a fitter to screw the screw bolt. This is typically achieved in that an inserted head of a screw bolt is accessible on at least one side at a sufficient angle so that a wrench can be attached and moved.

When the intermediate piece is fastened, the upper side typically rests on the turntable and thus usually also on the hub flange. The underside, which is parallel to this, is typically in contact with the rotor blade flange. Due to the offset arrangement of the through holes, a different pitch circle diameter of the hub flange to the pitch circle diameter of the rotor blade flange can be compensated for.

The intermediate piece according to the second aspect of the invention is preferably designed in such a way that it is solely capable of holding the rotor blade. If several intermediate pieces are then used, safety is increased, since even in the event of a failure of an intermediate piece, for example in the event of material failure or breakage, a single further intermediate piece would be sufficient to prevent the rotor blade from falling.

According to a third aspect, the invention relates to the use of an intermediate piece according to the second aspect of the invention in a method according to the first aspect of the invention, which comprises inserting at least one intermediate piece for hanging attachment.

An intermediate piece according to the second aspect of the invention can be used particularly advantageously in a method according to the first aspect of the invention, in which the intermediate piece is fastened to the hub and to the rotor blade flange each with a screw bolt.

The advantages of an adapter that is used in a method according to the invention, already described in connection with the method according to the first aspect and the connector according to the second aspect of the invention, also apply to the use of an adapter according to the third aspect of the invention.

• 1 zeigt eine Rotorblattanordnung mit einer Nabe und einem Rotorblatt im vollständig montierten Zustand.
• 2 zeigt ein Verfahren zum Instandhalten einer Windenergieanlage gemäß der vorliegenden Erfindung.
• 3 zeigt eine Rotorblattanordnung mit einem gelösten Rotorblatt.
• 4 zeigt eine Rotorblattanordnung mit einer montierten Gewindestange mit einem Hydraulikzylinder, wobei das Rotorblatt noch nicht abgesenkt ist.
• 5 zeigt die Rotorblattanordnung von 4, wobei das Rotorblatt abgesenkt ist.
• 6 zeigt die Rotorblattanordnung von 5 mit montierten Zwischenstücken.
• 7 zeigt ein montiertes Zwischenstück in größerer Detailliertheit.
• 8 zeigt die Rotorblattanordnung von 6 mit entfernten Gewindestangen.

Further advantages and features of the invention will become apparent from the following exemplary embodiments, which are described with reference to the accompanying drawings.

• 1 shows a rotor blade arrangement with a hub and a rotor blade in the fully assembled state.
• 2 shows a method for maintaining a wind turbine according to the present invention.
• 3 shows a rotor blade arrangement with a detached rotor blade.
• 4th shows a rotor blade arrangement with a mounted threaded rod with a hydraulic cylinder, the rotor blade not yet being lowered.
• 5 FIG. 8 shows the rotor blade assembly of FIG 4th with the rotor blade lowered.
• 6th FIG. 8 shows the rotor blade assembly of FIG 5 with mounted spacers.
• 7th shows a mounted adapter in greater detail.
• 8th FIG. 8 shows the rotor blade assembly of FIG 6th with removed threaded rods.

1 shows a rotor blade assembly 10 with a hub 100 and a rotor blade 200 . The hub 100 is around an axis A. rotatable.

The hub 100 has a hub flange 105 on which the rotor blade 200 with a rotor blade flange 210 is attached. The hub 100 also has two more hub flanges 106 , 107 to which further rotor blades can be attached. However, the invention is described below only with reference to the hub flange 105 described.

2 shows an exemplary embodiment of the method according to the invention for maintaining a wind energy installation. Simultaneously shows 2 Embodiments of the method according to the invention for releasing a rotor blade and its extensions.

In step S1, a rotor blade on which maintenance or servicing is to be carried out is aligned in a position pointing at least approximately vertically downward in the direction of gravity, as seen from the hub. This is done by suitable rotation of the hub and locking of a brake usually present in the wind energy installation.

In step S2, three screw bolts with which the rotor blade is attached to the hub are removed. This is done by turning the bolt in a direction in which the bolt is unscrewed. This frees threaded bores in the rotor blade flange into which threaded rods can subsequently be screwed.

In step S3, three threaded rods, which are each connected to a hydraulic cylinder as a lifting means, are screwed into the threaded bores which were exposed in step S2. This is done by turning the threaded rods appropriately. The hydraulic cylinders are placed on the rotor blade flange so that they can be supported on the rotor blade flange.

In step S4, the rotor blade is held by means of the hydraulic cylinder in a position in which the rotor blade flange adjoins the turntable. For this purpose, the lower pressure chambers of the hydraulic cylinders are placed under sufficiently high pressure by connecting and operating a hydraulic pump so that an upwardly directed total force exerted on the rotor blade by the hydraulic rods is at least as great as the force of gravity of the rotor blade.

All screw bolts are then loosened in step S5. Thus, after step S5 has been carried out, the rotor blade is only held on the hub by the threaded rods.

In step S6, the rotor blade is then lowered by means of the hydraulic cylinder. This is done by lowering the pressure in the lower chambers of the hydraulic cylinders. In this case, the pressure is reduced to such an extent that the total upward force exerted on the rotor blade by the threaded rods becomes smaller than the force of gravity of the rotor blade. This causes the rotor blade to move downwards. This continues until a limit is reached. The rotor blade is thus lowered and released from the hub flange.

Then, in step S7, three intermediate pieces are attached to the rotor blade flange and to the hub. It is fastened by means of screw bolts, with each intermediate piece being fastened to the rotor blade flange with a screw bolt and to the hub with a further screw bolt. The rotor blade is no longer only held on the hub by the three threaded rods, but also by the three intermediate pieces.

In step S8, the three threaded rods are unscrewed. This means that the rotor blade is only held on the hub by the intermediate pieces. In this state, the rotor blade is suspended from the hub. A movable turntable part in the hub is no longer connected to the rotor blade and is freely rotatable.

Thereafter, in step S9, the movable turntable part is rotated with respect to the rotor blade and the hub by an angle of rotation of 100 °. This ensures that a gearwheel of a motor-gearbox combination used for the adjustment of the angle of attack comes into engagement with the usual working range of the rotor blade of approximately 0 ° to 5 ° at a point of a toothed ring which is not yet worn.

Then in step S10 the three threaded rods, which are each connected to a hydraulic cylinder, and which were already screwed in in step S3 and unscrewed again in step S8, are screwed back into the bores of the rotor blade flange. The hydraulic cylinders are placed back onto the hub flange so that they can be supported on it. The rotor blade is no longer only held on the hub by the intermediate pieces, but also by the threaded rods.

The intermediate pieces are then removed in step S11. This is done by unscrewing the respective screw bolts with which the intermediate pieces are attached to the hub and to the rotor blade. After step S11 has been carried out, the rotor blade only hangs on the threaded rods.

In step S12, the rotor blade is then pulled up by means of the hydraulic cylinder. This takes place in that the pressure in the lower pressure chambers of the hydraulic cylinder is increased to such an extent that the threaded rods exert an upward force on the rotor blade which is greater than the force of gravity of the rotor blade. This causes the rotor blade to move upwards until it hits the hub flange.

When the rotor blade flange rests against the hub flange again, the screw bolts, which were removed in step S5 are screwed back into bores in the rotor blade flange in step S13. In this way, the rotor blade is fastened to the hub again by the screw bolts.

In step S14, the threaded rods, which are no longer required to hold the rotor blade, are unscrewed. Screw bolts are then screwed again into the bores into which the threaded rods were screwed.

Steps S1 to S6 of 2 represent an exemplary embodiment of the method for releasing a rotor blade according to illustrative configurations of the first aspect of the invention. Steps S1 to S7 represent an exemplary embodiment of the method according to the first aspect of the invention, which is expanded to include the attachment of intermediate pieces. Steps S1 to S8 represent an exemplary embodiment of the method according to the first aspect of the invention, which is expanded such that the rotor blade is fastened in a hanging manner.

If that is in 2 The method illustrated is carried out using two intermediate pieces according to the second aspect of the invention, an exemplary embodiment of a use according to the third aspect of the invention results.

The status after individual procedural steps will now be explained with reference to 3 until 8th explained in more detail. For any deviations between the representations in the figures and the in 2 The procedural steps shown are included.

3 shows the rotor blade assembly 10 from 1 with the rotor blade lowered and thus a state after step S6. The rotor blade 200 is from the hub 100 spaced and is supported by three threaded rods 300 , 310 , 320 held. The threaded rods 300 , 310 , 320 extend downward from an inner ring 120 of the hub flange 105 . The inner ring 120 is supported by an outer ring 110 surround. The outer ring is standing 110 with respect to the hub, while the inner ring 120 is rotatable with respect to the hub. This forms the inner ring 120 a movable turntable part. Together form the outer ring 110 and the inner ring 120 a slewing ring.

The state in 3 corresponds to that after the method for releasing a rotor blade has been carried out according to an exemplary embodiment of the first aspect of the invention.

4th shows the rotor blade assembly 10 in sectional view with mounted threaded rods before lowering the rotor blade. So shows 4th the state after step S3.

The threaded rods 300 , 310 , 320 are in the rotor blade flange 210 screwed in. Deviating from the in 2 However, the embodiment described is only the threaded rod 310 with a hydraulic cylinder 400 tied together. The other two threaded rods 300 , 320 each have a nut at their end remote from the rotor blade 305 , 325 on, which limit the mobility of the threaded rods downwards.

The hydraulic cylinder 400 has a piston 410 with a piston rod 420 on. The threaded rod 310 is directly in the extension of the piston rod 420 educated.

Furthermore, the piston 400 a pressure chamber 430 on, which is below the piston 410 is arranged. By applying pressure in the pressure chamber 430 becomes an upward force on the piston 410 exercised. The upward force can through the threaded rod 310 on the rotor blade 200 be transmitted. A method step of holding the rotor blade by means of the hydraulic cylinder in a position in which the rotor blade flange adjoins the turntable (compare step S4 of FIG 2 ) can thus be carried out by reducing the pressure in the pressure chamber 430 with the help of a pump is increased at least so far that the upward force of the threaded rod 310 on the rotor blade 200 the gravitational force of the rotor blade 200 compensated.

5 shows the rotor blade assembly 10 from 4th , also in sectional view, with the rotor blade 200 was lowered. So shows 5 a state after step S6 of 2 , with those referring to 4th declared deviation must be taken into account.

The piston 410 is now in a lower position. The nuts are also located 305 , 325 in their lower positions, in which they are on the movable turntable part 120 rest. Through the nuts 305 , 325 an additional holder of the rotor blade is provided in the lower position, whereby the piston 410 is relieved.

6th shows the rotor blade assembly 10 from 5 , with two additional spacers 500 , 550 were attached. The in 6th The state shown thus corresponds to that after step S7 has been carried out in FIG 2 , taking into account that in 6th only two spacers 500 , 550 are shown while 2 describes an example with three spacers.

The two intermediate pieces 500 , 550 are both with the outer ring 110 of the hub flange 105 as well as with the rotor blade flange 210 tied together. This is how they hold the rotor blade 200 at the hub 100 firmly and thus enable the threaded rods 300 , 310 , 320 can be removed without the rotor blade falling.

The attachment of the rotor blade with the help of the intermediate piece 500 is more detailed in 7th shown. 7th thus also shows an embodiment of the intermediate piece according to the second aspect of the invention.

The intermediate piece 500 has a main body 510 on which two through holes 520 , 530 having. The through holes 520 , 530 are formed in opposite, parallel flat surfaces and are arranged offset to one another.

The intermediate piece 500 is with a bolt 600 which has a head 610 has and through the through hole 520 passes through it, on the outer ring of the hub flange 105 attached. Also is the intermediate piece 500 with a bolt 650 which has a head 660 has and through the through hole 530 passes through, on the rotor blade flange 210 attached. The heads 610 , 660 the bolt 600 , 650 serve to screw in and unscrew the screw bolts 600 , 650 .

8th shows the rotor blade assembly 10 from 6th , with the three threaded rods 300 , 310 , 320 are away. The intermediate pieces 500 , 550 now hold the rotor blade 200 alone. The rotor blade is attached to the hub in a hanging manner. The state shown corresponds to that after step S8 of FIG 2 , taking into account the already mentioned difference that in the 6th and 8th only two spacers are shown.

List of reference symbols

A.

axis

10

Rotor blade assembly

100

hub

105

Hub flange

106

Hub flange

107

Hub flange

110

Outer ring

120

Inner ring, movable turntable part

200

Rotor blade

210

Rotor blade flange

300

Threaded rod

305

mother

310

Threaded rod

320

Threaded rod

325

mother

400

Hydraulic cylinder

410

Pistons

420

Piston rod

430

Pressure chamber

500

Intermediate piece

510

Main body

520

Through hole

530

Through hole

550

Intermediate piece

600

Bolt

610

head

650

Bolt

660

head

Claims (7)

Method for maintaining a wind power plant, in which at least one rotor blade (200) is attached to a hub (100) of the wind power plant in an adjustable angle of attack by means of a slewing ring (110, 120) during operation of the wind power plant, and a movable rotating ring part (120) with the hub (100) ) is rotatable and firmly connected to a rotor blade flange (210) of the rotor blade (200) by means of a plurality of screw bolts, the method comprising the following steps: - hanging fastening of the rotor blade (200) on the hub (100), wherein for hanging fastening of the rotor blade (200) on the hub (100) at least one intermediate piece (500, 550) on the hub (100) and on the rotor blade (200 ) is attached, - Rotating the movable turntable part (120) with respect to the rotor blade flange (210), and - Fastening the rotor blade (200) to the turntable (110, 120). Procedure according to Claim 1 wherein the at least one intermediate piece (500, 550) is fastened to the hub (100) or to the rotor blade flange (210) with a screw bolt (600, 650). Procedure according to Claim 1 or 2 , wherein at least two intermediate pieces (500, 550) are attached to the hub (100) and to the rotor blade (200). Method according to one of the Claims 1 until 3 wherein the step of fastening the rotor blade (200) to the turntable (110, 120) comprises the following steps: - screwing at least one threaded rod (300, 310, 320), which is connected to a lifting means (400), into a threaded bore in the rotor blade flange (210), - removing the at least one intermediate piece (500, 550) so that the rotor blade (200) is only held by the at least one threaded rod (300, 310, 320), - pulling up the rotor blade (200) by means of the at least one lifting means (400), fastening the rotor blade (200) to the movable turntable part (120) by screwing in a plurality of screw bolts. Method according to one of the Claims 1 until 4th , wherein the movable turntable part (120) is rotated by at least 10 ° or 100 °. Intermediate piece (500, 550) for hanging a rotor blade (200) on a hub (100) of a wind turbine, which has a flat top side and a flat bottom side parallel thereto, with at least one through hole (520, 530) being formed both in the top side and in the bottom side, wherein the through holes (520, 530) are accessible from a space between the top and bottom, so that in each case a screw bolt (600, 650) can be inserted into the through hole (520, 530) and screwed into an adjacent threaded hole, and one through hole (530) in each case in the lower side being offset from the corresponding through hole (520) in the upper side. Use of at least one intermediate piece (500, 550) according to Claim 6 in a method according to one of the Claims 1 until 5 .

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