Rotor blades for wind turbines

Abstract

A rotor blade for a wind turbine, the rotor blade comprising a hollow blade body (6) having a root (10) and a tip (13), wherein the blade body (6) is divided along a dividing plane (7) into two body parts (8, 9), one body part extending from the root (10) to a first connecting section (11) and the other body part extending from a second connecting section (12) to the tip (13), wherein the first connecting section (11) and the second connecting section (12) are adapted to overlap each other in a connected position.

Description

Technical Field

[0001] The invention relates to a rotor blade for a wind turbine, comprising a hollow blade body having a root and a tip. Background Art

[0002] A wind turbine typically includes at least two (three in most installations) rotor blades attached to a hub. The rotor blades interact with the wind, causing the hub to rotate. When the hub is coupled to a generator, electrical energy is generated, as is well known.

[0003] Wind turbines are installed onshore, but offshore wind turbines are also well known. Over the years, especially offshore wind turbines have increased in size. As the height of the wind turbine tower increases, the length of the rotor blades also increases. This makes the production and transportation of the rotor blades difficult. Summary of the invention

[0004] It is an object of the present invention to provide an improved rotor blade.

[0005] In order to solve this problem, a rotor blade for a wind turbine is provided, comprising a hollow blade body having a root and a tip, wherein the rotor blade is characterized in that the blade body is divided into two body parts along a dividing plane, one body part extending from the root to a first connecting section, and the other body part extending from the second connecting section to the tip, wherein the first connecting section and the second connecting section are adapted to overlap each other in a connected position.

[0006] The inventive rotor blade is split into two blade body parts which are easier to produce due to their reduced length. Moreover, the delivery and transportation to the installation side is simplified. They can then be connected to each other on site so that the complete long rotor blade can then be installed to the hub.

[0007] In a preferred embodiment, the dividing plane is in the region of the blade with a convex peripheral geometry. The overall shape of the rotor blade usually changes greatly from the root with a cylindrical cross section to the tip with a wing-shaped cross section. In length, usually starting near the root, the circumference or the cross section widens to a maximum value and tapers towards the tip, also changing the geometry of the cross section. According to a preferred embodiment, the dividing plane is arranged in the region of the blade with a convex peripheral geometry when viewed from the side of the blade. In this region, the cross section or the circumference is still widened, at its maximum value or slightly reduced, but in any case is relatively large, so that a large overlap of the first connecting section and the second connecting section is achieved in the connecting position.

[0008] In an alternative, it is also possible to arrange the dividing plane in a region in which the rotor blade has a single curved cross section as seen in the direction from the root to the tip. A single curved cross section means that the cross section has a circular, elliptical or oval shape. It does not change direction but always has a convex peripheral edge along the dividing plane as seen from the inside of the blade. Such a geometry in the region of the dividing plane facilitates a simple connection of the two body parts.

[0009] In a preferred embodiment, the splitting plane is in a region where the blade has a convex peripheral geometry and where the blade has a single curved cross section as seen in the direction from the root to the tip. In this embodiment, the splitting plane is arranged in a region that gives a convex peripheral geometry and a single curved cross section. This embodiment allows the positive effects of two splitting plane positions to be combined. Both possible positions enhance the structural performance and achieve a lighter and more secure connection. If both possible positions are now selected for arranging the splitting plane according to an embodiment of the invention, positive structural and mechanical advantages can be used.

[0010] In a further embodiment of the rotor blade, the first connecting section and the second connecting section have a tapered geometry suitable for inserting one connecting section into the other connecting section. The tapered geometry allows for an easier alignment and assembly of the two body parts, while the overlapping sections also allow for a simple but mechanically strong connection of these body parts. The corresponding tapered geometry at the two connecting sections is very easy to produce and allows for a simple assembly, since only the two connecting sections need to be pushed into each other.

[0011] In an alternative to providing a conical geometry at the connection sections, it is possible that at least one of the connection sections has a stepped geometry. The connection section preferably has a reduced diameter and an abutment shoulder. The other connection section has a larger inner diameter, so that the stepped connection section can be pushed into the other connection section, which abuts with its front surface at the abutment shoulder. It is of course also possible to provide such an abutment shoulder at the second connection section, which can have a larger inner diameter at the connection section, so that both connection sections are stepped, one connection section has a reduced outer diameter, the other connection section has an enlarged inner diameter, and the two connection sections are pushed into each other so as to overlap each other and abut at the respective abutment shoulders.

[0012] Regardless of whether a conical or stepped geometry is provided at the connecting section(s), the connecting sections are designed to interlock in a form-fitting manner so that they fit perfectly into one another. This form-fitting interlocking means that in the overlapping area, the body parts or the connecting sections are attached to one another without large gaps or seams, but directly to one another, so that a certain fixing means (fixture) is already given after attaching the body parts to one another, without providing special fixing or connecting means.

[0013] Preferably, the first connection section provided at the body portion including the root is inserted into the second connection section provided at the body portion having the tip.

[0014] A further preferred embodiment is characterized in that at the first connection section and / or at the second connection section one or more seams are provided, which extend from the end edge over at least a part of the length of the connection section. Although at least one seam is advantageous, preferably a plurality of seams are provided, which are arranged around the periphery and are spaced equidistant from one another. The seam or seams enhance the flexibility of the first connection section and / or the second connection section, which allows an even better form-fitting connection of the body parts. The seam or seams are directed towards the root or the tip. If more than one seam is provided, the seams define a kind of flexible finger extending at the free end edge of the respective connection section.

[0015] In order to connect the body parts or to strengthen the connection, connection or reinforcement means are provided which extend at the inner surface and bridge the transition area from the first connection section to the second connection section. These connection or reinforcement means are preferably arranged or attached to the inner surface so that the outer surface is smooth and the two body parts merge without significant steps or shoulders or grooves at the outer surface.

[0016] The connection or reinforcement device includes one or more webs or sheets attached to the inner surface. These webs or sheets allow covering a larger area and are very easy to be attached to the corresponding inner surface very firmly. Among these webs or sheets, the connection or reinforcement device may include at least one web or sheet extending at least 360 degrees along the inner periphery. The annular web or sheet covers the entire annular transition area and is attached to the two inner surfaces of the body part. It can extend very far into the corresponding body part, so that the attachment area or area at the two body parts is very large, for firmly anchoring the web or sheet at the corresponding surface.

[0017] Alternatively or additionally, the connection or reinforcement device may also include a plurality of ribbon-like or strip-like webs or sheets, which extend in the longitudinal direction over the transition region and are spaced apart from each other along the inner periphery. The ribbon-like or strip-like webs or sheets are also firmly anchored and fixed to the corresponding inner surface of the bridge transition region. They are preferably arranged together with the circular webs or sheets and extend into the corresponding body part, even longer than the annular webs or sheets. The ribbon-like or strip-like webs or sheets are preferably arranged along the inner periphery in a manner spaced apart from each other by equal distances, so that a uniform distribution is achieved.

[0018] Whichever web or sheet is attached, the web or sheet is preferably attached by means of a hardened binder, by lamination or by vacuum-assisted resin transfer molding. There are a variety of ways to tightly anchor or embed the web at the corresponding surface. Whichever way is chosen, they are all based on tightly bonding or gluing the corresponding web to the corresponding body part.

[0019] The dividing plane itself is preferably located in an inner section of the blade body closer to the root, since in this region a corresponding convex and single curvilinear geometry is preferably provided.

[0020] Besides the rotor blade itself, the invention also relates to a wind turbine comprising a rotor blade having at least one rotor blade as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. However, the accompanying drawings are only principle sketches, which are designed only for illustrative purposes and do not limit the present invention. The accompanying drawings show:

[0022] Figure 1 shows a principle sketch of an inventive wind turbine comprising three inventive rotor blades,

[0023] Figure 2 a perspective exploded sketch showing an inventive rotor blade of a first embodiment,

[0024] Figure 3 A partial sketch of a cross section of a rotor blade in the connection region of two body parts is shown, wherein a web-like connection of reinforcement means is provided,

[0025] Figure 4 Shown according to Figure 3 A sketch of a web-like connecting member or reinforcing means is provided, and

[0026] Figure 5 A principle sketch of an inventive rotor blade according to a second embodiment is shown in an exploded view. DETAILED DESCRIPTION

[0027] Figure 1 An inventive wind turbine 1 is shown, comprising a tower 2 and a nacelle 3 and a hub 4, to which in this embodiment three inventive rotor blades 5 are attached. As is well known, the rotor blades 5 interact with the wind, causing the hub 4 to rotate. This rotation drives a generator arranged in the nacelle 3 for generating electrical energy.

[0028] Figure 2 A principle sketch is shown in the form of an exploded view of a rotor blade 5 according to a first embodiment. In the following, a number of embodiments are described. The same reference numerals will be used for identical or comparable parts of the respective embodiments.

[0029] like Figure 2 The rotor blade 5 shown in , comprises a hollow blade body 6 which is divided along a dividing plane 7 into two body parts 8, 9 which can be pushed into each other or connected to each other as indicated by arrows P. The first blade body 8 extends from a root 10 to a first connecting section 11, while the second body part 9 extends from a second connecting section 12 to a tip 13.

[0030] In the connection location, such as Figure 3 As shown in Figure 3 Shows Figure 2 5 , the body parts 8 , 9 are pushed into each other with their respective connecting sections 11 , 12 , wherein in this embodiment the first connecting section 11 of the first body part 8 is pushed into the second connecting section 12 of the second body part 9 . Figure 3 As shown, both connection sections 11, 12 are tapered, thereby allowing simple alignment and assembly of the connection sections 11, 12 and allowing them to be attached to each other in a form-fitting manner, as shown in FIG. Figure 3 as shown in .

[0031] The dividing plane 7 is arranged in the region of the rotor blade 5, in which region the Figure 3 As shown in , the blade has a convex peripheral geometry when viewed from the side of the blade. Figure 3 As can be clearly seen in FIG. 1 , the circumference widens in the region of the dividing plane 7 from the left to a maximum circumference and then narrows again.

[0032] In addition, as in Figure 1As shown in the exploded view in , the dividing plane 7 is arranged in the region of the blade having a single curved cross section. The cross section of the connecting sections 11, 12 is circular or elliptical, so that from the inside of the blade, these connecting sections have a single curved cross section or are convex all around the periphery. As explained above, arranging the dividing plane 7 in a convex and single curved region enhances the structural performance and enables the two body parts 8, 9 to be connected together more lightly and more firmly by means of a form-fitting connection of the connecting sections 11, 12 (preferably via the conical geometry of the connecting sections 11, 12).

[0033] Figure 3 A connection or reinforcement device 22 is shown which is arranged at the inner surface 14, 15 of the respective body part 8, 9 or the respective connection section 11, 12. The connection or reinforcement device 13 comprises a web 16, such as a glass fiber web or a carbon fiber web or the like, which has an annular shape and extends at least 360 degrees along the inner periphery, thereby covering a transition area 17 where the inner surface 14 becomes the inner surface 15. The web 16 extends in the longitudinal direction into the two body parts 8, 9 and overlaps a certain area of ​​the inner surface 14, 15, into which area the web is tightly embedded by means of a hardened bonding agent or by lamination or by vacuum-assisted resin transfer molding or the like. The web 16 connects the body parts 8, 9 and strengthens the connection and also transfers shear loads from one body part to the other.

[0034] Figure 4 Shown according to Figure 3 , in which, in addition to the web 16, a plurality of further webs 18 in the form of bands or strips are attached to the respective inner surfaces 14, 15, which extend even further into the respective body portions 8, 9. They obviously extend over the web 16 and the respective transition region 17 and serve to further improve the connection or reinforcement and shear load transfer.

[0035] Of course, additional fixing means can be used to fix the body parts 8, 9 to each other in the overlapping connection section, such as bolt and nut connections, etc., which are not shown in detail. Obviously, due to the forces acting on the rotor blade when in motion and thus on the connection area, the connection of the body parts 8, 9 needs to be as strong as possible.

[0036] at last, Figure 5A further embodiment of an inventive rotor blade 5 is shown, which likewise comprises a hollow blade body 6 which is divided along a dividing plane 7 into two body parts 8, 9, one body part extending from a root 10 to a first connecting section 11 and the other body part extending from a second connecting section 12 to a tip 13. Also in this embodiment, the dividing plane 7 is arranged in a region where the rotor blade 5 has a convex peripheral geometry when viewed from the side of the blade and has a single curvilinear cross section when viewed in the direction from the root to the tip, as with regard to Figure 1 Already explained.

[0037] In this embodiment, the connecting section 11 shows a plurality of slits 19 extending from the end edge 20 over at least a portion of the length of the connecting section 11. These slits 19 are preferably evenly distributed around the circumference and define respective flexible fingers 21. These flexible fingers 21 enhance the flexibility of the connecting section 11, which is advantageous for a good form fit of the connecting sections 11, 12.

[0038] Although the fingers 21 are provided only at the first connecting section 11 , it is also possible to provide the second connecting portion 12 with corresponding fingers 21 or to provide both connecting portions 11 , 12 with fingers 21 .

[0039] Although the present invention has been described in detail with reference to the preferred embodiments, the present invention is not limited to the disclosed examples, and a skilled person can derive other variations from the disclosed examples without departing from the scope of the present invention.

Claims

1. A rotor blade for a wind turbine, the rotor blade comprising a hollow blade body (6) having a root (10) and a tip (13), characterised in that The hollow blade body (6) is divided into a first body part and a second body part along a dividing plane (7), the first body part extending from the root (10) to a first connecting section (11), and the second body part extending from the second connecting section (12) to the tip (13), wherein the first connecting section (11) and the second connecting section (12) are adapted to overlap each other in a connected position; wherein the dividing plane (7) is in a region in which the rotor blade (5) has a convex peripheral geometry when viewed from the side of the rotor blade and has a single curvilinear cross section when viewed in the direction from the root (10) to the tip (13), wherein the cross section has a convex peripheral edge all the way along the dividing plane when viewed from the inside of the rotor blade; wherein the circumference of the first body portion continuously decreases from the first connecting section to the end of the root, and the circumference of the second body portion continuously increases from the tip toward the second connecting section; Wherein, the first connection section and the second connection section have a conical geometry, which is configured to insert one connection section into the other connection section, the conical geometry of the first connection section is defined by an outer periphery that gradually decreases toward the dividing plane, and the conical geometry of the second connection section is defined by an inner periphery that gradually increases toward the dividing plane.

2. The rotor blade according to claim 1, characterized in that The cross-section is circular or elliptical or oval.

3. The rotor blade according to claim 1 or 2, characterized in that The connecting sections (11, 12) are interlocked by means of a positive fit.

4. The rotor blade according to claim 1 or 2, characterized in that: The first connecting section (11) is inserted into the second connecting section (12).

5. The rotor blade according to claim 1 or 2, characterized in that: One or more slits (19) are provided at the first connecting section (11) and / or at the second connecting section (12), said slits extending from an end edge (20) over at least a portion of the length of the connecting section (11).

6. The rotor blade according to claim 1 or 2, characterized in that A connecting or reinforcing means is provided which extends at the inner surface (14, 15) and bridges a transition region (17) from the first connecting section (11) to the second connecting section (12).

7. The rotor blade according to claim 6, characterized in that The connection or reinforcement means comprises one or more webs (16, 18) or sheets attached to the inner surface (14, 15).

8. The rotor blade according to claim 7, characterized in that The connection or reinforcement means comprises at least one web (16) or sheet extending along the inner periphery over at least 360 degrees.

9. The rotor blade according to claim 7, characterized in that The connection or reinforcement means comprises a plurality of webs (18) or sheets in the form of bands or strips extending in the longitudinal direction over the transition zone and spaced apart from one another along the inner periphery.

10. The rotor blade according to claim 7, characterized in that The webs (16, 18) or sheets are attached by means of a hardened bonding agent, by lamination or by vacuum assisted resin transfer moulding.

11. The rotor blade according to claim 1 or 2, characterized in that The dividing plane (7) is located at the inner section of the hollow blade body (6).

12. A wind turbine comprising a rotor having at least one rotor blade (5) according to any one of claims 1-11.

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