Methods, sets and blades for installation of a wind turbine blade

Abstract

The present disclosure relates to wind turbine blades (22), sets and methods (100) for mounting a wind turbine blade (22) to a wind turbine rotor hub (20). A method comprises hoisting and moving (110) a blade (22) to approach a rotor hub (20) such that a guiding funnel (33) guides a pin (24). One of the blade (22) and rotor hub (20) comprises the pin (24), and the other of the blade (22) and rotor hub (20) comprises the funnel (33) to receive the pin (24). A shock absorber (35) at least partially surrounds the guiding funnel (33) in a circumferential direction of the guiding funnel (33) to absorb kinetic energy along at least a radial direction (37) of the blade (22). The method further comprises further moving (120) the blade (22) towards the rotor hub (20), and introducing (130) a plurality of fasteners into a pitch bearing (72).

Description

METHODS, SETS AND BLADES FOR INSTALLATION OF A WIND TURBINE BLADETECHNICAL FIELD

[0001] The present disclosure relates to methods for mounting a wind turbine blade to a wind turbine rotor hub, specifically to a rotor hub atop a wind turbine tower. More particularly, the present disclosure relates to guiding and centering the blade during blade installation. The present disclosure further relates to wind turbine rotor hubs, wind turbine blades, sets of hub-wind turbine blade(s) and wind turbines.BACKGROUND

[0002] Modern wind turbines are commonly used to supply electricity into the electrical grid. Wind turbines of this kind generally comprise a tower and a rotor arranged on the tower. The rotor, which typically comprises a rotor hub and a plurality of blades, is set into rotation under the influence of the wind on the blades. Said rotation generates a torque that is normally transmitted through a rotor shaft to a generator, either directly (“directly driven” or “gearless”) or through the use of a gearbox. This way, the generator produces electricity which can be supplied to the electrical grid.

[0003] The wind turbine rotor hub may be rotatably coupled to a front of the nacelle. The wind turbine rotor hub may be connected to a rotor shaft, and the rotor shaft may then be rotatably mounted in the nacelle using one or more rotor shaft bearings arranged in a frame inside the nacelle. The nacelle is a housing arranged on top of a wind turbine tower that may contain and protect the gearbox (if present) and the generator (if not placed outside the nacelle) and, depending on the wind turbine, further components such as a power converter, and auxiliary systems.

[0004] A wind turbine may often be installed in remote landscapes, on hill-tops or offshore locations subjected to high winds. A known way of mounting a wind turbine includes the steps of transporting the different elements to the site of the wind turbine, assembling the tower sections and the tower, lifting the wind turbine nacelle with a large lifting device such as a crane, and mounting the nacelle on top of the tower. Then the wind turbine rotor hub can be lifted with the crane and mounted to a rotor shaft and / or the nacelle. Alternatively, the rotor hub can be mounted to the nacelle and then the nacelle-hub assembly can be hoisted.

[0005] Afterwards, one or more blades are mounted to the wind turbine rotor hub. The rotor hub generally comprises a plurality of pitch bearings with holes to which the blades can be connected to. The blade may comprise a plurality of fasteners, such as pins or studs, at its blade root. During installation, these fasteners are fitted into the holes in the corresponding pitch bearing.

[0006] The installation of wind turbine blades has become increasingly challenging due to the general tendency to considerably increase the size and weight of modern wind turbines, and therefore the wind turbine blades. Blades of modern wind turbines may be more than 70 or 80 meters, or even more than 100 meters long. During installation, a wind turbine blade may be hoisted towards the rotor hub with a lifting device such as a crane. The wind may cause sudden movements, and possibly oscillations, of the wind turbine components such as blades and nacelle during the hoisting operation and while approaching the blade to the corresponding blade pitch bearing of the rotor hub. If the wind blows strongly, the lifting device, or at least a portion thereof, may experience oscillations too. This may increase the risk of damage to the wind turbine blade or to other parts of the wind turbine, e.g. the pitch bearing or the blade fasteners.

[0007] If the blade is being installed offshore, the waves through periods and heights of the waves, the seabed and the foundation depth may also contribute to a relative movement between the blade and the rotor hub during blade installation as the vessel and the installed wind turbine components (nacelle up-tower) may also move. Mounting the blade to the rotor hub may therefore be complicated and time-consuming. Delays may lead to an increase in the cost of installation, especially in offshore installations where the use of dedicated vessels may be required.

[0008] In order to install the blade, manual aid may often be required. This can lead to an increase of the risk for the operator, especially if the operator may be standing near the blade.

[0009] In order to reduce oscillations of blades during hoisting and installation, the use of tagline systems, i.e. control ropes from a vessel, crane or ground floor that are connected to the lifting device to prevent oscillations, are known. Other systems and tools are also known. For example, patent US11852119B2 proposes a blade installation method in which a guiding element and a receptacle are used during blade installation.

[0010] Due to the forces and loads experienced by at least the blade being lifted, very large forces and loads arise when the guiding element and the receptacle meet. This may damage or even break at least one of the guiding element and the receptacle. Loads may transfer to the blade and to the rotor hub to which the receptable and the guiding element are connected, thereby also stressing the blade and the rotor hub.

[0011] The present disclosure aims to at least partially reduce one or more of the aforementioned drawbacks.SUMMARY

[0012] In an aspect of the present disclosure, a method for mounting a wind turbine blade to a wind turbine rotor hub is provided. The blade comprises a root including a plurality of fasteners, and the rotor hub comprises a pitch bearing including a plurality of holes surrounding a hub opening. One of the blade and the hub comprises a pin, and the other of the blade and the hub comprises a guiding funnel to receive the pin. The method comprises hoisting the blade and moving the blade to approach the rotor hub substantially along a longitudinal direction of the blade such that the guiding funnel guides the pin. A shock absorber at least partially surrounds the guiding funnel in a circumferential direction of the guiding funnel to absorb kinetic energy along at least a radial direction of the blade. The method further comprises further moving the blade towards the rotor hub, and introducing the plurality of fasteners into the plurality of holes of the pitch bearing.

[0013] According to this aspect, a guiding funnel surrounds a pin when the blade is moved towards the rotor hub. The contact between the guiding funnel and the pin helps to suitably position the blade with respect to the rotor hub such that the fasteners of the blade may then be suitably inserted into the pitch bearing holes. The shock absorber dampens at least the forces exerted on the guiding funnel along a radial direction of the blade when the guiding funnel contacts the pin.

[0014] An effective and safe blade installation may therefore be achieved. The pin and the funnel may not break during the installation of the blade, and applied forces may be transferred less to the rotor hub and / or the blade.

[0015] Throughout this disclosure, a guiding funnel may be understood as an element including a tapering portion, for example a tapering inner surface. The tapering of the guiding funnel helps to guide the blade by receiving the pin when moving the blade towards the rotor hub.

[0016] In a further aspect, a wind turbine blade is provided. The wind turbine blade comprises a root portion and an airfoil portion. The root portion comprises a guiding funnel configured to receive a pin mounted on a hub to which the wind turbine blade is to be mounted. The blade further comprises a shock absorber at least partially surrounding the guiding funnel.

[0017] In a further aspect, a wind turbine comprising a rotor hub and a blade according to the previous aspect is provided. The rotor hub comprises a pin protruding from an inside of the rotor hub and away from the rotor hub, and the pin is surrounded by the guiding funnel.

[0018] In a further aspect, a set comprising a wind turbine rotor hub and a wind turbine blade configured to be mounted to the rotor hub is provided. The blade comprises a root including aplurality of fasteners, and the hub comprises a pitch bearing surrounding a hub opening. One of the blade and the rotor hub comprises a pin. The other of the blade and the rotor hub comprises a guiding funnel to receive the pin and a shock absorber at least partially surrounding the guiding funnel.BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 schematically illustrates a perspective view of one example of a wind turbine;

[0020] Figure 2 schematically illustrates an example of a hub and a nacelle of a wind turbine;

[0021] Figure 3 schematically illustrates a flowchart of an example of a method for mounting a wind turbine blade to a wind turbine rotor hub;

[0022] Figure 4 schematically illustrates an enlarged lateral view of an example of a wind turbine rotor hub and a wind turbine blade attached to the rotor hub, the rotor hub comprising a pin and the blade comprising a guiding and centering system surrounding the pin;

[0023] Figure 5 schematically illustrates a cross-sectional view of the example of the rotor hub and the blade of figure 4; and

[0024] Figure 6 schematically illustrates a cut-away cross-sectional view of the example of a hub comprising the blade of figures 4 and 5.DETAILED DESCRIPTION OF EXAMPLES

[0025] Reference now will be made in detail to embodiments of the disclosure, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the disclosure, not as a limitation. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope or spirit of the teaching. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present disclosure covers such modifications and variations as come within the scope of the appended claims and their equivalents.

[0026] Figure 1 is a perspective view of an example of a wind turbine 10. In the example, the wind turbine 10 is a horizontal-axis wind turbine. Alternatively, the wind turbine 10 may be a vertical-axis wind turbine. In the example, the wind turbine 10 includes a tower 15 that extends from a support system 14 on a ground 12, a nacelle 16 mounted on tower 15, and a rotor 18 that is coupled to nacelle 16. The rotor 18 includes a rotatable hub 20 and at least one rotor blade 22 coupled to and extending outward from the rotor hub 20. In the example, the rotor 18 has threerotor blades 22. In an alternative embodiment, the rotor 18 includes more or less than three rotor blades 22. The tower 15 may be fabricated from tubular steel to define a cavity (not shown in figure 1) between a support system 14 and the nacelle 16. In an alternative embodiment, the tower 15 is any suitable type of a tower having any suitable height. According to an alternative, the tower can be a hybrid tower comprising a portion made of concrete and a tubular steel portion. Also, the tower can be a partial or full lattice tower. A wind turbine 10 may be placed both onshore and offshore.

[0027] The rotor blades 22 are spaced about the rotor hub 20 to facilitate rotating the rotor 18 to enable kinetic energy to be transferred from the wind into usable mechanical energy, and subsequently, electrical energy. The rotor blades 22 are mated to the rotor hub 20 by coupling a blade root portion to the rotor hub 20 at a plurality of load transfer regions 26. The load transfer regions 26 may have a hub load transfer region and a blade load transfer region (both not shown in figure 1). Loads induced to the rotor blades 22 are transferred to the rotor hub 20 via the load transfer regions 26.

[0028] In examples, the rotor blades 22 may have a length ranging from about 15 meters (m) to about 90 m or more. Rotor blades 22 may have any suitable length that enables the wind turbine 10 to function as described herein. For example, non-limiting examples of blade lengths include 20 m or less, 37 m, 48.7 m, 50.2m, 52.2 m or a length that is greater than 91 m. As wind strikes the rotor blades 22 from a wind direction 28, the rotor 18 is rotated about a rotor axis 30. As the rotor blades 22 are rotated and subjected to centrifugal forces, the rotor blades 22 are also subjected to various forces and moments. As such, the rotor blades 22 may deflect and / or rotate from a neutral, or non-deflected, position to a deflected position.

[0029] Moreover, a pitch angle of the rotor blades 22, i.e., an angle that determines an orientation of the rotor blades 22 with respect to the wind direction, may be changed by a pitch system 32 to control the load and power generated by the wind turbine 10 by adjusting an angular position of at least one rotor blade 22 relative to wind vectors. Pitch axes 34 of rotor blades 22 are shown. During operation of the wind turbine 10, the pitch system 32 may particularly change a pitch angle of the rotor blades 22 such that the angle of attack of (portions of) the rotor blades are reduced, which facilitates reducing a rotational speed and / or facilitates a stall of the rotor 18.

[0030] In the example, a blade pitch of each rotor blade 22 is controlled individually by a wind turbine controller 36 or by a pitch control system 80. Alternatively, the blade pitch for all rotor blades 22 may be controlled simultaneously by said control systems.

[0031] Further, in the example, as the wind direction 28 changes, a yaw direction of the nacelle 16 may be rotated about a yaw axis 38 to position the rotor blades 22 with respect to wind direction 28.

[0032] In the example, the wind turbine controller 36 is shown as being centralized within the nacelle 16, however, the wind turbine controller 36 may be a distributed system throughout the wind turbine 10, on the support system 14, within a wind farm, and / or at a remote-control center. The wind turbine controller 36 includes a processor 40. Further, many of the other components described herein include a processor.

[0033] As used herein, the term “processor” is not limited to integrated circuits referred to in the art as a computer, but broadly refers to a controller, a microcontroller, a microcomputer, a programmable logic controller (PLC), an application specific, integrated circuit, and other programmable circuits, and these terms are used interchangeably herein. It should be understood that a processor and / or a control system can also include memory, input channels, and / or output channels.

[0034] Figure 2 is an enlarged sectional view of a portion of the wind turbine 10. In the example, the wind turbine 10 includes the nacelle 16 and the rotor 18 that is rotatably coupled to the nacelle 16. More specifically, the rotor hub 20 of the rotor 18 is rotatably coupled to an electric generator 42 positioned within the nacelle 16 by the main shaft 44, a gearbox 46, a high-speed shaft 48, and a coupling 50. In the example, the main shaft 44 is disposed at least partially coaxial to a longitudinal axis (not shown) of the nacelle 16. A rotation of the main shaft 44 drives the gearbox 46 that subsequently drives the high-speed shaft 48 by translating the relatively slow rotational movement of the rotor 18 and of the main shaft 44 into a relatively fast rotational movement of the high-speed shaft 48. The latter is connected to the generator 42 for generating electrical energy with the help of a coupling 50. Furthermore, a transformer 90 and / or suitable electronics, switches, and / or inverters may be arranged in the nacelle 16 in order to transform electrical energy generated by the generator 42 having a voltage between e.g. 400V to 1000 V into electrical energy having medium voltage (10 - 35 KV). Offshore wind turbines may have for example generator voltages between 650 V and 3500 V, and transformer voltages may for instance be between 30 kV and 70 kV. Said electrical energy is conducted via power cables from the nacelle 16 into the tower 15.

[0035] The gearbox 46, generator 42 and transformer 90 may be supported by a main support structure frame of the nacelle 16, optionally embodied as a main frame 52. The gearbox 46 may include a gearbox housing that is connected to the main frame 52 by one or more torque arms 103. In the example, the nacelle 16 also includes a main forward support bearing 60 and a main aft support bearing 62. Furthermore, the generator 42 can be mounted to the main frame 52 by decoupling support means 54, in particular in order to prevent vibrations of the generator 42 to be introduced into the main frame 52 and thereby causing a noise emission source.

[0036] Optionally, the main frame 52 is configured to carry the entire load caused by the weight of the rotor 18 and components of the nacelle 16 and by the wind and rotational loads, and furthermore, to introduce these loads into the tower 15 of the wind turbine 10. The rotor shaft 44, generator 42, gearbox 46, high-speed shaft 48, coupling 50, and any associated fastening, support, and / or securing device including, but not limited to, support 52, and forward support bearing 60 and aft support bearing 62, are sometimes referred to as a drive train 64.

[0037] In some examples, the wind turbine may be a direct drive wind turbine without gearbox 46. Generator 42 operate at the same rotational speed as the rotor 18 in direct drive wind turbines. They therefore generally have a much larger diameter than generators used in wind turbines having a gearbox 46 for providing a similar amount of power than a wind turbine with a gearbox.

[0038] The nacelle 16 also may include a yaw drive mechanism 56 that may be used to rotate the nacelle 16 and thereby also the rotor 18 about the yaw axis 38 to control the perspective of the rotor blades 22 with respect to the wind direction 28.

[0039] For positioning the nacelle 16 appropriately with respect to the wind direction 28, the nacelle 16 may also include at least one meteorological measurement system which may include a wind vane and anemometer. The meteorological measurement system 58 can provide information to the wind turbine controller 36 that may include wind direction 28 and / or wind speed. In the example, the pitch system 32 is at least partially arranged as a pitch assembly 66 in the rotor hub 20. The pitch assembly 66 includes one or more pitch drive systems 68 and at least one sensor 70. Each pitch drive system 68 is coupled to a respective rotor blade 22 (shown in figure 1) for modulating the pitch angel of a rotor blade 22 along the pitch axis 34. Only one of three pitch drive systems 68 is shown in figure 2.

[0040] In the example, the pitch assembly 66 includes at least one pitch bearing 72 coupled to rotor hub 20 and to a respective rotor blade 22 (shown in figure 1) for rotating the respective rotor blade 22 about the pitch axis 34. The pitch drive system 68 includes a pitch drive motor 74, a pitch drive gearbox 76, and a pitch drive pinion 78. The pitch drive motor 74 is coupled to the pitch drive gearbox 76 such that the pitch drive motor 74 imparts mechanical force to the pitch drive gearbox 76. The pitch drive gearbox 76 is coupled to the pitch drive pinion 78 such that the pitch drive pinion 78 is rotated by the pitch drive gearbox 76. The pitch bearing 72 is coupled to pitch drive pinion 78 such that the rotation of the pitch drive pinion 78 causes a rotation of the pitch bearing 72.

[0041] Pitch drive system 68 is coupled to the wind turbine controller 36 for adjusting the pitch angle of a rotor blade 22 upon receipt of one or more signals from the wind turbine controller 36. In the example, the pitch drive motor 74 is any suitable motor driven by electrical power and / or a hydraulic system that enables pitch assembly 66 to function as described herein. Alternatively,the pitch assembly 66 may include any suitable structure, configuration, arrangement, and / or components such as, but not limited to, hydraulic cylinders, springs, and / or servomechanisms. In certain embodiments, the pitch drive motor 74 is driven by energy extracted from a rotational inertia of rotor hub 20 and / or a stored energy source (not shown) that supplies energy to components of the wind turbine 10.

[0042] The pitch assembly 66 may also include one or more pitch control systems 80 for controlling the pitch drive system 68 according to control signals from the wind turbine controller 36, in case of specific prioritized situations and / or during rotor 18 overspeed. In the example, the pitch assembly 66 includes at least one pitch control system 80 communicatively coupled to a respective pitch drive system 68 for controlling pitch drive system 68 independently from the wind turbine controller 36. In the example, the pitch control system 80 is coupled to the pitch drive system 68 and to a sensor 70. During normal operation of the wind turbine 10, the wind turbine controller 36 may control the pitch drive system 68 to adjust a pitch angle of rotor blades 22.

[0043] According to an embodiment, a power generator 84, for example comprising a battery and electric capacitors, is arranged at or within the hub 20 and is coupled to the sensor 70, the pitch control system 80, and to the pitch drive system 68 to provide a source of power to these components. In the example, the power generator 84 provides a continuing source of power to the pitch assembly 66 during operation of the wind turbine 10. In an alternative embodiment, power generator 84 provides power to the pitch assembly 66 only during an electrical power loss event of the wind turbine 10. The electrical power loss event may include power grid loss or dip, malfunctioning of an electrical system of the wind turbine 10, and / or failure of the wind turbine controller 36. During the electrical power loss event, the power generator 84 operates to provide electrical power to the pitch assembly 66 such that pitch assembly 66 can operate during the electrical power loss event.

[0044] In the example, the pitch drive system 68, the sensor 70, the pitch control system 80, cables, and the power generator 84 are each positioned in a cavity 86 defined by an inner surface 88 of hub 20. In an alternative embodiment, said components are positioned with respect to an outer surface of hub 20 and may be coupled, directly or indirectly, to the outer surface.

[0045] In an aspect of the disclosure, a method for mounting a wind turbine blade to a wind turbine rotor hub is provided. The rotor hub may be atop a wind turbine tower. The blade comprises a root including a plurality of fasteners, e.g. studs. The rotor hub comprises a pitch bearing including a plurality of holes, e.g. three pitch bearings, surrounding a hub opening. One of the blade and the rotor hub comprises a pin. The other of the blade and the hub comprises a guiding funnel configured to receive the pin. An example of this method 100 is shown in the flowchart of figure 3. The method comprises, at block 110, hoisting the blade and moving theblade to approach the rotor hub substantially along a longitudinal direction of the blade such that the guiding funnel guides the pin. Also, a shock absorber at least partially surrounds the guiding funnel in a circumferential direction of the guiding funnel to absorb kinetic energy along at least a radial direction of the blade (the radial direction of the blade is perpendicular to the longitudinal direction of the blade, and the circumferential direction of the funnel and the radial direction of the blade may specifically be parallel). The method further comprises, at block 120, further moving the blade towards the rotor hub, and at block 130, introducing the plurality of fasteners into the plurality of holes of the pitch bearing of the rotor hub.

[0046] Therefore, when the blade is moved towards the rotor hub, the guiding funnel helps to guide and center the blade with respect to the rotor hub. As contact between the guiding funnel and the pin involves large forces and loads, the shock absorber helps to dampen these forces and loads. The blade is further moved towards the rotor hub, and the fasteners of the blade are inserted into the pitch bearing holes of the pitch bearing attached to the rotor hub. The shock absorber can act as a damper from the beginning of the contact between the pin and the guiding funnel until the insertion of the fasteners.

[0047] In some examples, the method may be performed offshore. I.e., the blade may be hoisted and moved with a lifting device, e.g. a crane, arranged on a vessel.

[0048] In some examples, the hub may comprise the pin and the blade may comprise the guiding funnel and the shock absorber. For example, the guiding funnel may be connected, e.g. attached, to an inside of the blade. And while the blade is moved towards the rotor hub, the guiding funnel may surround the pin protruding through the rotor hub opening and away from the rotor hub. In other examples, the blade may comprise the pin and the rotor hub may comprise the guiding funnel and the shock absorber.

[0049] Figure 4 schematically illustrates an enlarged lateral view of an example of a wind turbine rotor hub 20 and a wind turbine blade 22 already attached to the rotor hub 20. The rotor hub 20 comprises the pin 24 in this example. The pin may be attached, for example bolted, to a plate 31 inside the rotor hub. The plate may be a pitch mounting plate. The hub plate 31 may be perpendicular to a pitch axis 34, see also figure 2. When the rotor hub 20 and the blade 22 are attached, the longitudinal direction of the blade 39 may be parallel to the pitch axis 34. The pin 24 may comprise an elongated body. The body may be cylindrical. The pin 24 may comprise a flange for attaching the pin 24 to the rotor hub 20. The flange may be integrally formed with the body of the pin in some examples. In other examples, a bendable connector, e.g. a hinge, may connect the body and the flange of the pin.

[0050] The method may further comprise unfolding the pin 24, e.g. its body, from a stored position to an extended position. As the pin 24 is to protrude through the rotor hub opening in thisexample, the pin 24 may be kept in stored, e.g. folded, position until the blade 22 is to be installed. Keeping the pin 24 in a stored position may be convenient, as an operator may move around more easily and safely with a stored pin 24. In some examples, the pin 24 may be folded, e.g. against a hub plate 31 , until it is to be used. In other examples, the pin 24 may be retracted, e.g. due to having a telescopic body. Still in other examples, the pin 24 may comprise a plurality of sections which may be attached to each other to form the pin 24.

[0051] In this example, the blade 22 comprises a guiding funnel and a shock absorber surrounding the pin 24. The set of guiding funnel and shock absorber may be referred to as guiding and centering system 27. The system 27 is connected to an inside of the blade 22, e.g. to a blade plate or flange 29. The blade plate 29 may extend in a plane perpendicular to a longitudinal direction 39 of the blade 22. The guiding funnel 33 may extend between a first end 57 and a second end 59. The first end 57 may be farther away from the tip of the blade than the second end 59. The first end 57 may therefore surround the pin 24 before the second end 59. The funnel may comprise a hole for receiving the pin 24, for example a through hole. The first 57 and second ends 59 of the funnel may be open ends.

[0052] An example of shock absorber 35 is shown in figure 5. Figure 5 schematically illustrates a cross-sectional view of the example of the rotor hub 20 and the blade 22 of the example of figure 4. The shock absorber 35 absorbs kinetic along a radial direction 37 of the blade 22, i.e. along a direction which is perpendicular to the longitudinal direction 39 of the blade 22.

[0053] Due to wind gusts and e.g. waves if offshore, when the pin 24 contacts the guiding funnel 33, the pin 24 exerts a force against the guiding funnel 33 along a certain direction. This force may generally be decomposed in a radial force (along the radial direction 37) and in a longitudinal force (along the longitudinal direction 39, and therefore direction of installation) of the blade. The radial component of the force may be particularly large. The shock absorber 35 and the system 27 may specifically be configured to dampen a force in the radial direction 37. The shock absorber 35 and the system 27 may further be configured to dampen a force in the longitudinal direction 39. In other words, the shock absorber 35 may further absorb kinetic energy along the longitudinal direction 39 of the blade 22.

[0054] The guiding funnel 33 may comprise a portion 41 that tapers towards an inside of the blade 22, specifically along the longitudinal direction 39. This portion may be referred to as guiding portion 41. The pin 24 may be surrounded by the guiding portion 41 of the guiding funnel 33 first. The guiding portion 41 comprises an inner surface which tapers towards the inside of the blade 22. An outer surface of the guiding portion 41 may also taper towards the inside of the blade 22, see e.g. figure 5. The guiding portion 41 may have a truncated cone shape in some examples. The tapering of the guiding portion 41 may help to orient the blade 22 with respect to the hubflange, for example to align the root flange with the pitch bearing of the rotor hub. The blade 22 may start to be oriented before its fasteners touch the rotor hub 20. The tapering of the guiding portion 41 may also help to transfer loads to the shock absorber 35, specifically along a radial direction 37, but also along the longitudinal direction 39 of the blade 22.

[0055] The guiding and centering system 27 may further comprise a base 45. The base 45 may be connected, specifically attached, to the blade 22, e.g. bolted to it. The base 45 may support the shock absorber 35 and the guiding funnel 33. The shock absorber 35 may be connected, e.g. attached, to the base 45. The base 45 may comprise a bottom wall 47 and a side wall 49 in some examples. The bottom wall 47 and the side wall 49 may be integrally formed in some of these examples.

[0056] In some examples, the shock absorber 35 may be compressed along the radial direction 37 of the blade 22 when the guiding funnel 33 contacts the pin 24. In some of these examples, the bottom wall 47 may comprise a recess 51. The recess 51 may extend in a radial direction 37 of the blade 22 and in a circumferential direction of the blade 22. The base 45 may comprise a slidable plate 53. The plate 53 may be slidable along the radial direction 37 and may e.g. have a disc shape. The slidable plate 53 may be attached to the funnel 33, e.g. bolted to it. Therefore, the guiding funnel 33 may be moved radially 37 as the slidable plate 53 slides radially along the bottom wall 47, thereby compressing the shock absorber. The side wall 49 may limit the radial movement of the shock absorber 35.

[0057] In other examples, a slidable plate 53 may be provided in a different location of the system 27, e.g. of the base 45. For example, the base may further comprise a wall above the bottom wall 47, this other wall including the slidable plate 53.

[0058] In some examples, the base 45 may comprise more than one sidewall. Still in other examples, the base 45 may lack a sidewalls and e.g. comprise a bottom wall 47 only. Depending on the type of shock absorber, e.g. size, shape, material, etc., a suitable connection between the shock absorber and the blade 22 may be provided. I.e., the system 27 may connected to the inside of the blade 22 in any suitable manner which allows the system 27 to work as described throughout this disclosure.

[0059] Going back to some examples of method 100, after the pin 24 is guided by the guiding funnel 33, e.g. surrounded by the guiding portion 41 , the pin 24 may then be surrounded by a centering portion 55 of the guiding funnel 33. The centering portion 55 may be a substantially cylindrical portion (hollow cylinder). The centering portion 55 may limit a movement of the pin 24 in the radial direction more than the guiding portion 41. The centering portion 55 may help to keep the achieved orientation between the blade and the rotor hub. For example, the root flange of theblade 22 may be aligned with the pitch bearing of the rotor hub 20, and this alignment may be maintained while the blade 22 is further moved to the rotor hub 20.

[0060] The base 45, specifically its bottom wall 47, may have a through hole. A portion of the guiding funnel 33 may extend through this hole. The centering portion 55 may also extend through a through hole of the plate or flange 29 of the blade 22 to which the system 27 is connected.

[0061] The above details and explanations may also be applicable (mutatis mutandis) if the rotor hub comprises the guiding funnel and the shock absorber, and the blade comprises the pin. For example, system 27 may be connected, e.g. attached, to the rotor hub, e.g. to a hub plate. The guiding funnel 33 may taper towards an inside of the rotor hub in these examples. The first end 57 and second end 59 of the funnel may be aligned in the pitch axis direction.

[0062] In a further aspect, a wind turbine blade 22 is provided. The blade comprises a root portion and an airfoil portion. The root portion, specifically an inside thereof, comprises a guiding funnel 33 configured to receive a pin 24 mounted on a rotor hub 20 to which the wind turbine blade 22 is to be mounted, and a shock absorber 35 at least partially surrounding the guiding funnel 33. As mentioned before, the guiding funnel and the shock absorber may be part of a centering and guiding system 27. The shock absorber is specifically configured to absorb kinetic energy along at least a radial direction 37 of the blade 22 when the guiding funnel and the pin touch.

[0063] The details and explanations provided with respect to the previous method and with respect to figures 3 - 5 may be applied to, and combined with, this aspect, and vice versa.

[0064] For example, the tapering portion 41 of the guiding funnel 33 may taper along a desired direction of insertion of the blade 22. Specifically an inner surface 61 (radial inner surface) of the guiding portion 41 may taper. At least a portion of the outer surface 63 (radial outer surface) of the guiding portion 41 may also taper, see figure 5. The direction of insertion may be parallel to longitudinal direction of the pin 24 which will enter the funnel 33 when approaching the rotor hub 20 and the blade 22. The direction of insertion and the longitudinal direction of the pin 24 may be parallel to the pitch axis 34.

[0065] The blade may further comprise a base 45. For example, the system 27 may further comprise a base 45 connected to the blade 22. The base 45 may support the shock absorber 35 and the guiding funnel 33. For example, the shock absorber 35 may be connected, e.g. attached, to the base 45, and the guiding funnel 33 may be connected to the base 45, e.g. attached to a slidable plate 53 slidable along the base 45.

[0066] The base 45 may be connected, e.g. attached, to the blade 22, e.g. to a blade plate or flange 29 inside the blade 22. The blade plate 29 may for example be arranged within a rootportion of the blade 22. Attachment between two elements may be mechanical (e.g. with bolts) and / or chemical (e.g. with adhesive).

[0067] The shock absorber 35 may be made of one or more suitable materials. For example, the shock absorber may comprise, e.g. be made of, elastomer, e.g. rubber; or the shock absorber 35 may be inflatable. For example, the shock absorber 35 may comprise one or more inflatable cavities. The shock absorber 35 may comprise a plurality of through holes, specifically along the longitudinal direction 39 of the blade 22. For example, an elastomer shock absorber 35 may comprise through holes extending along the longitudinal direction 39 of the blade 22. The through holes my in some examples comprise a circular or hexagonal cross-section.

[0068] In other examples, the shock absorber 35 may comprise friction plates or other suitable elements or mechanisms which enables the shock absorber to operate as described herein.

[0069] Once such a blade 22 has been mounted to the rotor hub 20, the guiding and centering system 27 of the blade 22 and the pin 24 of the rotor hub 20 may remain therein. I.e., the pin 24 will remain attached to the rotor hub 20, and the system 27 may remain attached to the blade inside. The pin 24 will also remain inserted into the system 27. If the blade 22 includes the pin 24, and the rotor hub 20 includes the guiding funnel 33 and the shock absorber 35, these elements may also remain at their locations once the blade has been attached to the rotor hub, e.g. to a pitch bearing.

[0070] Accordingly, in a further aspect a wind turbine 10 is provided. The wind turbine may be an offshore wind turbine. The turbine 10 comprises a rotor hub 20 with a pin 24 as described herein, and further comprises a blade 22 according to the previous aspect. The rotor hub 20 comprises a pin 24 protruding from an inside of the rotor hub 20 and away from the rotor hub 20, and the pin 24 is surrounded by the guiding funnel 33. The pin 24 may protrude beyond the guiding funnel, specifically beyond its second end 59, see figure 4.

[0071] All the blades 22 attached to the rotor hub 20, e.g. three blades, may comprise the guiding funnel 33 and the shock absorber 35, e.g. the guiding and centering system 27. The rotor hub 20 may for example include three pins 24, e.g. three metallic pins. The guiding funnel 33 of each blade 22 may surround the corresponding pin 24 of the rotor hub 20. Figure 6 schematically illustrates a cut-away perspective view of the example of a wind turbine rotor hub 20 and the blade 22 of figures 4 and 5 connected to a corresponding pitch bearing 72.

[0072] A pitch bearing 72 typically comprises an inner ring and an outer ring, and usually a plurality of rolling or roller elements between the inner and outer ring. The wind turbine blade 22 may be attached either to the inner ring or to the outer ring, whereas the rotor hub 20 may be attached to the other of the inner and outer rings. In the example of figure 6, the blade 22 is attached to the inner ring of the pitch bearing 72.

[0073] According to a further aspect, a set comprising a wind turbine rotor hub 20 and a wind turbine blade 22 is provided. The blade 22 comprises a root including a plurality of fasteners and the rotor hub 20 comprises a pitch bearing surrounding a hub opening. One of the blade 22 and the rotor hub 20 comprises a pin 24, and the other of the blade 22 and the hub 20 comprises a guiding funnel 33 to receive the pin 24 and a shock absorber 35 at least partially surrounding the guiding funnel 33. The shock absorber may be configured to absorb kinetic energy along at least a radial direction 37 of the blade 22.

[0074] The pin 24 may be configured to protrude from an inside of the rotor hub through a hub opening and away from the rotor hub 20 in some examples. An inside of the blade 22 may comprises the guiding funnel 33. The guiding funnel may be configured to receive the pin 24 when approaching the blade 22 to the rotor hub 20 for mounting the blade 22 to the rotor hub 20. The inside of the blade 22 may further comprises the shock absorber.

[0075] The rotor hub 20 and the wind turbine 10 of the set may be separate, i.e. , the blade 22 may have not yet been attached to the rotor hub 20, or the rotor hub and the blade may be joined, i.e., the blade has already been attached to the rotor hub.

[0076] The features and explanations of the previous aspects, e.g. with respect to figures 3 - 6, may also be applied to, and combined with, the features and explanations of this aspect, and vice versa.

[0077] For example, at least a portion of an inner surface 61 of the guiding funnel 33 may taper towards the inside of the blade 22, e.g. along the longitudinal direction 39 of the blade 22. The shock absorber 35 may comprise elastomer such as rubber and / or inflatable cavities.

[0078] In these or other examples, the guiding funnel 33 may be connected to a base 45. The base 45 may comprise a first wall 47 attached to a blade plate 29 and a second wall 49 extending from the first wall. The shock absorber may be enclosed by the first wall and the second wall. The base 45 may comprise a slidable plate 53, specifically slidable along a radial direction 37 of the blade 22, and the guiding funnel 33 may be attached to the slidable plate 53.

[0079] The pin 24 may be configured to be moved between a stored position and an extended or unfolded position.

[0080] In some examples, the guiding and centering system 27 including the guiding funnel 33 and the shock absorber 35 (and e.g. the base 45) may be centered inside the blade 22. I.e., a longitudinal axis of the system 27 may be centered in the blade 22. In other words, when the blade 22 is attached to the rotor hub 20, the longitudinal axis of the guiding funnel 33 overlaps the pith axis 34. Similarly, the pin 24 may be centered with respect to the corresponding hub opening. I.e., when the pin 24 protrudes through the hub opening, it may be centered with respect to the opening. The pin 24 may extend along the pitch axis 34.

[0081] This written description uses examples to disclose a teaching, including the preferred embodiments, and also to enable any person skilled in the art to put the teaching into practice, including making and using any devices or systems and performing any incorporated methods. The patentable scope is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. Aspects from the various embodiments described, as well as other known equivalents for each such aspects, can be mixed and matched by one of ordinary skill in the art to construct additional embodiments and techniques in accordance with principles of this application. If reference signs related to drawings are placed in parentheses in a claim, they are solely for attempting to increase the intelligibility of the claim, and shall not be construed as limiting the scope of the claim.

Claims

CLAIMS1. A method (100) for mounting a wind turbine blade (22) on a wind turbine rotor hub (20), the blade (22) comprising a root including a plurality of fasteners and the rotor hub (20) comprising a pitch bearing (72) including a plurality of holes surrounding a hub opening, wherein one of the blade (22) and rotor hub (20) comprises a pin (24) and the other of the blade (22) and rotor hub (20) comprises a guiding funnel (33) to receive the pin (24), the method (100) comprising: hoisting the blade (22) and moving (110) the blade (22) to approach the rotor hub (20) substantially along a longitudinal direction of the blade (39) such that the guiding funnel (33) guides the pin (24), wherein a shock absorber (35) at least partially surrounds a portion of the guiding funnel (33) in a circumferential direction of the guiding funnel (33) to absorb kinetic energy along at least a radial direction of the blade (37); further moving (120) the blade (22) towards the rotor hub (20); and introducing (130) the plurality of fasteners into the plurality of holes of the pitch bearing (72).

2. The method of claim 1 , wherein the shock absorber (35) further absorbs kinetic energy along a longitudinal direction of the blade (39).

3. The method of claim 1 or claim 2, wherein the shock absorber (35) is compressed along a radial direction of the blade (37) when the guiding funnel (33) contacts the pin (24).

4. The method of any of claims 1 - 3, further comprising unfolding the pin (24) from a stored position to an extended position.

5. The method of any of claims 1 - 4, wherein the guiding funnel (33) is mounted on the blade (22), and wherein the pin (24) is mounted on the rotor hub (20), optionally wherein the pin (24) is mounted on a pitch mounting plate.

6. The method of any of claims 1 - 5, wherein the blade (22) is hoisted and moved (110) with a lifting device arranged on a vessel.

7. A wind turbine blade (22) comprising a root portion and an airfoil portion, the root portion comprising: a guiding funnel (33) configured to receive a pin (24) mounted on a rotor hub (20) to which the wind turbine blade (22) is to be mounted; and a shock absorber (35) at least partially surrounding the guiding funnel (33).

8. The blade of claim 7, further comprising a base (45) connected to the blade (22), the base (45) supporting the shock absorber (35) and the guiding funnel (33).

9. The blade of claim 8, wherein the guiding funnel (33) is slidable in a radial direction of the blade (37) along the base (45).

10. The blade of any of claims 7 - 9, wherein the shock absorber (35) comprises elastomer.

11. The blade of claim 10, wherein the shock absorber (35) comprises a plurality of through holes, specifically along a longitudinal direction of the blade (39).

12. The blade of any of claims 7 - 9, wherein the shock absorber (35) is inflatable.

13. A wind turbine (10) comprising a rotor hub (20) and the blade (22) of any of claims 7 - 12, wherein the rotor hub (20) comprises a pin (24) protruding from an inside of the rotor hub (20) and away from the rotor hub (20), and wherein the pin (24) is surrounded by the guiding funnel (33).

14. A set comprising a wind turbine rotor hub (20) and a wind turbine blade (22) configured to be mounted to the rotor hub (20), the blade (22) comprising a root including a plurality of fasteners and the rotor hub (20) comprising a pitch bearing (72) surrounding a hub opening; wherein one of the blade (22) and the rotor hub (20) comprises a pin (24), and wherein the other of the blade (22) and the rotor hub (20) comprises a guiding funnel (33) to receive the pin (24) and a shock absorber (35) at least partially surrounding the guiding funnel (33).

15. The set of claim 14, wherein the shock absorber (35) comprises rubber and / or inflatable cavities.

Images