Wind turbine blade with bearing cap, method for manufacturing wind turbine blade and wind turbine

Abstract

A wind turbine blade with a bearing cap, a method for manufacturing a wind turbine blade and a wind turbine. The invention relates to a wind turbine blade (1) for a wind turbine (2), the wind turbine blade (1) comprises a root section (3) for attaching the wind turbine blade (1) to a blade bearing of a wind turbine hub (4) of the wind turbine (2), a tip section (5), an intermediate section (6) interposed between the root section (3) and the tip section (5), and a bearing cap (7) attached to the root section (3), the invention relates to a wind turbine blade (1) for shielding a gap between the wind turbine hub (4) and the wind turbine blade (1) in an assembled state of the wind turbine blade (1) and the wind turbine hub (4). The bearing cap (7) is fixed to the wind turbine blade (1) by an adhesive layer of a first adhesive. The invention also relates to a method for manufacturing a wind turbine blade (1) and to a wind turbine (2).

Description

Technical Field

[0001] This invention relates to wind turbine blades with bearing caps. The invention also relates to a method for manufacturing wind turbine blades and a wind turbine. Background Technology

[0002] For wind turbines, it is known that a gap exists between the wind turbine hub and the wind turbine blades. Following this gap, blade bearings for the wind turbine blades are installed. These bearings are also known as "pitch bearings." The blade bearings are metallic and contain lubricant. To increase the life of the blade bearings and reduce the need for inspection and repair, the blade bearings should be protected from environmental factors such as rain and dust.

[0003] For this purpose, the gap must be protected by a protective device. A common protective device is a bearing cap, which is installed on the wind turbine blade to shield the gap. The bearing cap also traps grease that flows out of the bearing, thereby protecting the blade coating of the wind turbine from damage.

[0004] Several methods are known for attaching bearing caps to wind turbine blades. According to a common solution, the bearing cap is bolted to the wind turbine blade. For this purpose, bolt holes must be drilled into the root section of the wind turbine blade. However, the root section of the wind turbine blade, in particular, requires structural integrity to withstand high loads and moments. During the life of the wind turbine blade, the bolts and bolt holes are exposed to these loads and moments, leading to cracking and eventual failure of the wind turbine blade.

[0005] Document WO 2021 / 121497 A1 discloses a bearing cover for a wind turbine blade. The bearing cover comprises multiple bearing cover sections that are held together and clamped to the wind turbine blade by multiple tension bands having end supports, bolts, and nuts. For this purpose, the end supports of adjacent tension bands are bolted together, wherein these tension bands are secured by tightening bolts using corresponding nuts.

[0006] A significant drawback of solutions with drilled bolt holes and tension bands in the root section is related to the ellipticization of wind turbine blades. Due to their own weight, wind turbine blades placed on the ground tend to slightly change their cross-sectional shape from circular to elliptical. This effect is called ellipticization. Ellipticization will result in additional stress on bolts, bolt holes, and tension bands, especially when the wind turbine blades are in operation and are once again circular. Summary of the Invention

[0007] Therefore, the object of the present invention is to eliminate or at least partially eliminate the aforementioned disadvantages in the case of wind turbines. In particular, the object of the present invention is to create a wind turbine blade for a wind turbine, a method for manufacturing a wind turbine blade, and a wind turbine, all configured for securely and permanently attaching a bearing cap to the wind turbine blade in a simple and inexpensive manner.

[0008] The aforementioned objective is achieved through the claims. Therefore, the problem is solved by a wind turbine blade for a wind turbine having the features of independent claim 1, a method for manufacturing a wind turbine blade for a wind turbine according to appendix claim 9, and a wind turbine according to appendix claim 15. Other features and details of the invention become apparent from the dependent claims, the description, and the drawings. The features and details described in conjunction with the wind turbine blade according to the invention naturally also apply to the method for manufacturing a wind turbine blade according to the invention and the wind turbine according to the invention, and vice versa, so that disclosures relating to various aspects of the invention are always, or always, mutually referential.

[0009] According to a first aspect of the invention, this objective is achieved by a wind turbine blade for a wind turbine. The wind turbine blade includes a root section, a tip section, an intermediate section between the root section and the tip section, and a bearing cap attached to the root section to shield the gap between the wind turbine hub and the wind turbine blade in an assembled state with the wind turbine hub. The bearing cap is secured to the wind turbine blade by an adhesive layer of a first adhesive.

[0010] A wind turbine blade comprises three sections: a root section, a middle section, and a tip section. The longitudinal end of the wind turbine blade is formed by the root section and the tip section. Furthermore, the middle section lies between the root section and the tip section. Preferably, these three sections are seamlessly interconnected. Preferably, the root section has a circular cross-section, wherein the root section may undergo ellipticization, for example, during storage, handling, or operation. More preferably, the longest portion of the wind turbine blade is formed by the middle section.

[0011] At the root section, preferably spaced apart from the longitudinal root end of the wind turbine blade, a bearing cap is provided. Preferably, the bearing cap has: a connecting section for connecting the bearing cap to the root section; and a shielding section for shielding the gap between the wind turbine hub and the wind turbine blade in the assembled state of the wind turbine blade and the wind turbine hub. Essentially, the bearing cap may have the shape of a standard bearing cap, for example, having an L-shaped cross-section. Furthermore, the material of the bearing cap is preferably a common material used for standard bearing caps, such as metal, plastic, etc. The bearing cap may consist of multiple bearing cap elements that are combined together to form the bearing cap. Preferably, adjacent bearing cap elements have overlapping areas to provide continuous shielding of the gap.

[0012] The bearing cap is secured to the wind turbine blade by an adhesive layer of a first adhesive. The thickness of this adhesive layer is preferably between 1 mm and 10 mm. Preferably, this adhesive layer is configured to absorb shear stress, such as shear stress caused by the ellipticization of the wind turbine blade. For this purpose, it is preferable that the first adhesive, in its cured state, still possesses sufficient flexibility to follow the deformation of the wind turbine blade. Therefore, the connection between the bearing cap and the wind turbine blade resists the standard ellipticization of the wind turbine blade.

[0013] The wind turbine blade according to the invention has advantages over conventional wind turbine blades, namely: the bearing cap is fixed to the root section in a simple and inexpensive manner. The assembly of the bearing cap to the root section is improved due to the adhesive layer of the first adhesive. Furthermore, the adhesive layer allows for better compensation of tolerances, especially those caused by the ellipticity of the wind turbine blade, compared to using standard fixing bolts or tension bands. Additionally, it eliminates the need to drill bolt holes into the root section, which would compromise its integrity. Therefore, the lifespan of the wind turbine blade is increased compared to conventional wind turbine blades. Moreover, the adhesive layer provides a seal to protect the gap from environmental influences and to prevent grease from leaking from the blade bearing.

[0014] Preferably, the wind turbine blade includes a plurality of bolts secured to the wind turbine blade by a second adhesive, wherein these bolts protrude into a clearance hole in the bearing cap. Preferably, the chemical composition of the second adhesive differs from that of the first adhesive. Alternatively or additionally, a plurality of retainer clips, etc., may be provided at the wind turbine blade, secured to the wind turbine blade by the second adhesive, wherein these retainer clips protrude into a clearance hole in the bearing cap. Further preferably, the cured second adhesive has higher strength and / or greater hardness compared to the cured first adhesive. The bolts may be constructed as steel bolts, plastic bolts, etc. Preferably, the bolt includes a bolt head and a bolt shank, wherein the bolt head is secured to the wind turbine blade, and the bolt shank protrudes from the wind turbine blade into the clearance hole. Preferably, the surface of the bolt head facing the root segment matches the opposing surface of the root segment to provide a better bond between the bolt and the root segment. Preferably, the clearance hole has a larger diameter than the bolt shank to provide the possibility of relative movement of the bolt shank relative to the bearing cap. Further preferably, the bolt shank is at least partially cut off, for example, for metal bolts, or broken off, for example, for plastic bolts. The bolt serves to initially secure the bearing cap to the root section, for example, in conjunction with a nut, and preferably with a washer, until the first adhesive has fully cured. This has the advantage of improving the assembly of the bearing cap to the wind turbine blade in a simple and inexpensive manner.

[0015] According to another preferred improvement of the invention, the wind turbine blade may be provided with the bearing cap clearance hole constructed as a slot. Within the scope of the invention, a slot is considered to be a hole having a length different from its width. Preferably, the width of the clearance hole is equal to the diameter of the bolt shank. The longitudinal orientation of the slot is preferably along the circumferential direction of the wind turbine blade to better compensate for the ellipticity of the wind turbine blade. This has the advantage of being able to better compensate for the tolerance caused by ellipticity in a simple and inexpensive manner.

[0016] According to a preferred embodiment of the invention, the wind turbine blade comprises a plurality of 3D shapes, preferably in the root section, wherein the bolt head of a bolt is disposed on or within the 3D shape. The 3D shapes can have various shapes, such as cylindrical, dome-shaped, etc. Preferably, the bolt head has a shape that matches the 3D shape. Therefore, the contact surface between the bolt and the root section is increased, and the stability of the connection between the bolt and the root section is improved. Furthermore, the alignment of these portions is improved. More preferably, the 3D shapes are designed to reduce the notch effect. Therefore, sharp corners are avoided, and curves are preferred, for example, at the edges between the root section surface and the 3D shapes. This has the advantage of improving the connection between the bolt and the root section in a simple and inexpensive manner.

[0017] More preferably, the bolt head and the 3D shape have flat surfaces. Preferably, the flat surface of the bolt head is the surface facing away from the bolt shank. The flat surface of the 3D shape is the surface facing the flat surface of the bolt head. These flat surfaces are adhered together by a second adhesive. This has the advantage of improving the connection between the bolt and the root segment in a simple and inexpensive manner.

[0018] In a particularly preferred embodiment of the invention, the second adhesive is a fast-curing adhesive. Preferably, the second adhesive is configured to cure faster than the first adhesive. More preferably, the second adhesive has less elasticity compared to the first adhesive. This has the advantage of increasing the speed of the process of attaching the bolt to the root segment in a simple and inexpensive manner.

[0019] Preferably, the gap is filled with a third adhesive. Within the scope of the invention, filling the gap with a third adhesive means that the free volume of the gap not occupied by the bolt is completely or partially filled with the third adhesive. More preferably, the third adhesive has the same chemical composition as the first adhesive. Preferably, the third adhesive has a different chemical composition than the second adhesive. More preferably, the third adhesive has greater flexibility than the second adhesive. This has the advantage of further improving protection against environmental impact in a simple and inexpensive manner.

[0020] According to a preferred embodiment of the invention, the adhesive layer of the first adhesive has a certain thickness and flexibility to compensate for the ellipticity of the wind turbine blade during handling, storage, and operation. The degree of ellipticity of the wind turbine blade depends on its structure and materials. Therefore, the maximum degree of ellipticity of the wind turbine blade is known. The thicker the adhesive layer, the less flexibility of the first adhesive is required to compensate for the ellipticity. This has the advantage of further increasing the stability and lifespan of the connection between the bearing cap and the root section in a simple and inexpensive manner.

[0021] According to a second aspect of the invention, the objective is achieved by a method for manufacturing wind turbine blades. The method includes: - Provides wind turbine blades with root, middle, and tip sections. - Multiple bolts are secured to the root section via their bolt heads using a second adhesive. - A bearing cap with clearance holes is installed at the wind turbine blades, allowing bolts to protrude through the clearance holes. - By tightening the nuts at these bolts, the bearing cap is initially secured to the wind turbine blade. - An adhesive layer for applying the first adhesive between the bearing cap and the wind turbine blade, and - Allow the first adhesive to cure.

[0022] Preferably, the wind turbine blades are supplied in a fully assembled state, for example, having spacers, shear webs, spar caps, coatings, lightning protection devices, etc.

[0023] The bolt is secured to the root section using a second adhesive. Preferably, the bolt is secured to the root section at a predetermined location. More preferably, the bolt is secured to the root section so as to protrude vertically from the root section. The second adhesive may be applied to the predetermined location on the root section and / or the bolt head. Preferably, the second adhesive is configured as a fast-curing adhesive. Preferably, the second adhesive is cured by holding time, heat, UV light, etc. When the second adhesive can be cured by UV light and the bolt is made of translucent plastic, UV light is preferred.

[0024] A bearing cap is disposed at the root section of the wind turbine. The bearing cap includes multiple clearance holes. Preferably, the clearance holes are configured as slots. By disposing the bearing cap at the root section, a bolt shank is inserted into the clearance hole and protrudes through the clearance hole. A clearance is provided between the bearing cap and the root section. This clearance can be provided, for example, by the bolt head.

[0025] Furthermore, the bearing cap is initially secured to the wind turbine blade by tightening the nut at the bolt. Preferably, an additional washer is used between the nut and the bearing cap. Alternatively or additionally, a nut with an outer diameter significantly larger than the width of the clearance hole (e.g., equivalent to the outer diameter of a standard washer) can be used.

[0026] When the bearing cap is secured to the root section, an adhesive layer of a first adhesive is applied between the bearing cap and the wind turbine blade. Furthermore, the first adhesive is cured. Thus, the bearing cap is adhered to the wind turbine blade. Preferably, a first adhesive having a different chemical composition than a second adhesive is used. Preferably, the cured first adhesive has greater flexibility compared to the cured second adhesive. Alternatively or additionally, the first adhesive may be applied to the root section and / or the bearing cap before the bearing cap is initially secured to the root section.

[0027] The method for manufacturing wind turbine blades according to the present invention has all the advantages already described with respect to the wind turbine blades according to the first aspect of the invention. Therefore, the method for manufacturing wind turbine blades according to the present invention has advantages over conventional methods for manufacturing wind turbine blades, namely: the bearing cap is fixed to the root section in a simple and inexpensive manner. The assembly of the bearing cap to the root section is improved due to the adhesive layer of the first adhesive. Furthermore, by means of the adhesive layer, tolerances, especially those caused by the ellipticity of the wind turbine blade, can be compensated better than using standard fixing bolts or tension bands. Moreover, it is not necessary to drill bolt holes into the root section, which would compromise the integrity of the root section. Therefore, the lifespan of the wind turbine blade is increased compared to conventional wind turbine blades. In addition, the adhesive layer provides a seal to protect the gap from environmental influences and to prevent the loss of grease from the blade bearing.

[0028] It is particularly preferred that the nuts be removed after the adhesive layer has been applied. These nuts can be removed by unscrewing them with tools, pinching them, cutting them, for example, sawing them, grinding them, etc. This has the advantages of improving ellipticity compensation in a simple and inexpensive manner, and less stress being introduced into the bearing cap.

[0029] According to a preferred embodiment of the invention, a portion of the bolt protruding from the clearance hole is removed after the adhesive layer is applied. Preferably, the nut is also removed in this process. This removal can be performed by pinching them, cutting them, for example, sawing them, grinding them, etc. This has the advantages of improving ellipticity compensation in a simple and inexpensive manner, and less stress is introduced into the bearing cap.

[0030] Further preferably, the gap is filled with a third adhesive. Within the scope of the invention, filling the gap with a third adhesive means that the free volume of the gap not occupied by the bolt is completely or partially filled with the third adhesive. Further preferably, the third adhesive has the same chemical composition as the first adhesive. Preferably, the third adhesive has a different chemical composition than the second adhesive. Further preferably, the third adhesive has greater flexibility than the second adhesive. This has the advantage of further improving protection against environmental impact in a simple and inexpensive manner.

[0031] Preferably, multiple 3D shapes are manufactured onto the wind turbine blade, wherein bolt heads are arranged on or within the 3D shapes and fixed to the 3D shapes by a second adhesive. Accordingly, the 3D shapes are manufactured onto the root segment of the wind turbine blade before the bolts are fixed to the root segment. These 3D shapes can be configured as recesses and / or protrusions. The 3D shapes can have various shapes, such as cylindrical, dome-shaped, etc. Preferably, the bolt head has a shape that matches the recess. Therefore, the contact surface between the bolt and the root segment can be increased, and the stability of the connection between the bolt and the root segment can be improved. Furthermore, the alignment process of these parts can be improved using such 3D shapes. More preferably, the 3D shapes are designed to reduce notch effects. Therefore, sharp corners are avoided, and curves are preferred, for example, at the edges between the root segment surface and the 3D shapes. More preferably, the bolt head and the recess have flat surfaces. Preferably, the flat surface of the bolt head is a surface facing away from the bolt shank. The 3D-shaped flat surface is the flat surface facing the bolt head. These flat surfaces are adhered together by a second adhesive. This has the advantage of improving the connection between the bolt and the root segment in a simple and inexpensive way.

[0032] Further preferably, the first adhesive is injected into the gap between the root section and the bearing cap. This gap can be provided by spacers, bolt heads, the shape of the bearing cap, etc. Preferably, the injection of the first adhesive is performed using a dispensing gun or the like. This has the advantage of improving the application of the first adhesive used to form the adhesive layer in a simple and inexpensive manner.

[0033] According to a third aspect of the invention, the objective is achieved by a wind turbine. The wind turbine includes a tower, a nacelle, and a wind turbine hub. Furthermore, the wind turbine includes wind turbine blades according to the invention, which are attached to the wind turbine hub. The wind turbine blades are attached to the wind turbine hub in such a way that the gap between the root section and the hub housing of the wind turbine hub is shielded by a bearing cap of the wind turbine blade.

[0034] The wind turbine according to the invention possesses all the advantages already described with respect to the wind turbine blade according to the first aspect of the invention and the method for manufacturing the wind turbine blade according to the second aspect of the invention. Therefore, the wind turbine according to the invention has advantages over conventional wind turbines, namely: the bearing cap is fixed to the root section in a simple and inexpensive manner. The assembly of the bearing cap to the root section is improved due to the adhesive layer of the first adhesive. Furthermore, by means of the adhesive layer, tolerances, especially those caused by the ellipticity of the wind turbine blade, can be compensated better than using standard fixing bolts or tension bands. Moreover, it is not necessary to drill bolt holes into the root section, which would compromise the integrity of the root section. Therefore, the lifespan of the wind turbine blade is increased compared to conventional wind turbine blades. In addition, the adhesive layer provides a seal to protect the gap from environmental influences and to prevent the loss of grease from the blade bearing. Attached Figure Description

[0035] Other advantages, features, and details of the invention will be apparent from the following description, wherein working examples of the invention are described in detail with reference to the accompanying drawings. Thus, the features from the claims and those mentioned in the specification may be essential to the invention, whether used alone or in any combination. In the drawings: Figure 1 A schematic perspective view of a wind turbine according to a preferred embodiment of the present invention is shown. Figure 2 It shows Figure 1 A schematic detail of a wind turbine. Figure 3 A schematic detail drawing shows the bearing cap initially fixed at the root section. Figure 4 A schematic detail drawing shows the initial fixation of the bearing cap to the root section, and Figure 5 A preferred embodiment of the method according to the present invention is illustrated in a schematic flowchart.

[0036] Components with the same function and effectiveness Figure 1-5 Each is represented by the same reference numerals. Detailed Implementation

[0037] exist Figure 1 The wind turbine 2 according to a preferred embodiment of the present invention is shown in a schematic perspective view. Figure 2A wind turbine 2 is shown in schematic detail. The wind turbine includes a tower 12, a nacelle 13 mounted on the tower 12, and a wind turbine hub 4 mounted on the nacelle 13. Three wind turbine blades 1 according to the invention are assembled to the wind turbine hub 4. Each wind turbine blade 1 includes: a root section 3 fixed to the wind turbine hub 4; a tip section 5 forming the distal end of the wind turbine blade 1; and a middle section 6 disposed between the root section 3 and the tip section 5.

[0038] like Figure 2 As shown, the bearing cap 7 is fixedly attached to the root section 3 of the wind turbine blade 1, thereby shielding the invisible hub bearing of the wind turbine hub 4.

[0039] exist Figure 3 The diagram shows, in schematic detail, a bearing cover 7 initially fixed to the root section 3 of a wind turbine blade 1, with only one section of the bearing cover 7 shown.

[0040] Figure 4 Another schematic detail shows the initial fixation of the bearing cap 7 to the root segment 3. Multiple bolts 8 are adhered to the root segment 3 by a second adhesive, protruding from the root segment through the clearance hole 9 of the bearing cap 7. The clearance hole 9 is constructed as a slot to compensate for the tolerances and ellipticity of the wind turbine blade 1. The bearing cap 7 is initially fixed to the root segment by a washer 14 and a nut 10, which is tightened to the bolts 8. In this state, a gap 11 between the bearing cap 7 and the root segment is provided for the application of an adhesive layer for the first adhesive.

[0041] exist Figure 5 The preferred embodiment of a method for manufacturing a wind turbine blade 1 according to the present invention is illustrated in a schematic flowchart. In the first method operation 100, for example, a wind turbine blade 1 having a root section 3, a middle section 6, and a tip section 5 is placed on a transport platform having a holding clamp or the like. In the second method operation 200, a plurality of bolts 8 are secured to the root section 3 by means of a second adhesive through their bolt heads. Therefore, the bolt shanks of the bolts 8 protrude radially outward from the root section 3.

[0042] In the third method operation 300, the bearing cap 7, having a clearance hole 9, is arranged at the wind turbine blade 1 with bolts 8 protruding through the clearance hole 9. The bearing cap 7 can be configured as a section of multiple bearing caps 7. In the fourth method operation 400, the bearing cap 7 is initially fixed to the wind turbine blade 1 by tightening nuts 10 at these bolts. Thus, a gap 11 is formed between the bearing cap 7 and the root section 3. In the fifth method operation 500, an adhesive layer of the first adhesive is applied to the gap 11 between the bearing cap 7 and the wind turbine blade 1. Finally, in the sixth method operation 600, the first adhesive is cured.

Claims

1. A wind turbine blade (1) for a wind turbine (2), comprising a root section (3), a tip section (5), an intermediate section (6) between the root section (3) and the tip section (5) of a blade bearing for attaching the wind turbine blade (1) to a wind turbine hub (4) of the wind turbine (2), and a bearing cap (7) attached to the root section (3) for shielding the gap between the wind turbine hub (4) and the wind turbine blade (1) in the assembled state of the wind turbine blade (1) and the wind turbine hub (4). Its features are, The bearing cap (7) is fixed to the wind turbine blade (1) by the adhesive layer of the first adhesive.

2. The wind turbine blade (1) according to claim 1. Its features are, The wind turbine blade (1) includes a plurality of bolts (8) which are fixed to the wind turbine blade (1) by a second adhesive, wherein the bolts (8) protrude into the clearance hole (9) of the bearing cap (7).

3. The wind turbine blade (1) according to claim 2. Its features are, The clearance hole (9) of the bearing cover (7) is constructed as a slot.

4. The wind turbine blade (1) according to claim 2 or 3. Its features are, The wind turbine blade (1) includes multiple 3D shapes, wherein the bolt head of the bolt (8) is arranged on or in the 3D shape.

5. The wind turbine blade (1) according to claim 4. Its features are, The bolt head and recess have flat surfaces.

6. The wind turbine blade (1) according to any one of claims 2-5 Its features are, The second adhesive is a fast-curing adhesive.

7. The wind turbine blade (1) according to any one of claims 2-6. Its features are, The gap (9) is filled with a third adhesive.

8. The wind turbine blade (1) according to any one of the preceding claims. Its features are, The adhesive layer of the first adhesive has a thickness and flexibility that compensates for the ellipticization of the wind turbine blade (1) during handling, storage and operation of the wind turbine blade (1).

9. A method for manufacturing wind turbine blades (1), comprising: - Provide a wind turbine blade (1) having a root section (3), a middle section (6) and a tip section (5). - A second adhesive is used to secure multiple bolts (8) to the root section (3) through their bolt heads. - A bearing cap (7) with a clearance hole (9) is arranged at the wind turbine blade (1) such that the bolt (8) protrudes through the clearance hole (9). - The bearing cap (7) is initially fixed to the wind turbine blade (1) by tightening the nut (10) at the bolt (8). - An adhesive layer for applying a first adhesive between the bearing cap (7) and the wind turbine blade (1), and - Allow the first adhesive to cure.

10. The method according to claim 9, Its features are, Remove the nut (10) after the adhesive layer has been applied.

11. The method according to claim 9 or 10, Its features are, After the adhesive layer is applied, a portion of the bolt (8) protruding from the gap hole (9) is removed.

12. The method according to claim 11, Its features are, The gap (9) is filled with a third adhesive.

13. The method according to any one of claims 9-12, Its features are, A plurality of recesses are made in the wind turbine blade (1), wherein the bolt head is arranged in the recesses and fixed to the recesses by the second adhesive.

14. The method according to any one of claims 9-13, Its features are, The first adhesive is injected into the gap (11) between the root section (3) and the bearing cap (7).

15. A wind turbine (2), comprising a tower (12), a nacelle (13), and a wind turbine hub (4). Its features are, The wind turbine blade (1) according to any one of claims 1-8 is attached to the wind turbine hub (4).

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