LAMINATED STRUCTURE FOR CONNECTING THE FLANGE OF A WIND TURBINE ROTOR BLADE, CONNECTING ELEMENT, WIND TURBINE ROTOR BLADE AND METHOD FOR MANUFACTURING A LAMINATED STRUCTURE

Abstract

A laminate structure (146) for a flange connection of a wind turbine rotor blade (110) with at least one connecting element (144) comprising a bushing (148) and a core element (150), wherein - a first end (152) of the bushing (148) has a bore hole (156) with an inner thread (158) being adapted for accommodating a connection bolt, - a second end (154) of the bushing (148) has a bushing runout (160) with an inner recess (162), the inner recess (162) being of a funnel-like shape, - the core element (150) comprises an inner portion (166), a middle portion (168) and an outer portion (170), wherein -- the outer portion (170) tapers at an end (174) opposite to the inner portion (166), -- the inner portion (166) has a shape corresponding to the inner recess (162), - a first laminate layer (176) is wrapped around the inner portion (166) and the middle portion (168) of the core element (150), and - the wrapped core element (150) is inserted into the inner recess (162) with the inner portion (166) such that the first laminate layer (176) is arranged between the core element (150) and the bushing runout (160).

Description

1 / 20 LAMINATED STRUCTURE FOR CONNECTING THE FLANGE OF A WIND TURBINE ROTOR BLADE, CONNECTING ELEMENT, WIND TURBINE ROTOR BLADE AND METHOD FOR MANUFACTURING A LAMINATED STRUCTURE Description

[001] Laminated structure for connecting a flange of a wind turbine rotor blade, connecting element, wind turbine rotor blade and method for manufacturing a laminated structure.

[002] The invention relates to a laminated structure for connecting the flange of a wind turbine rotor blade, to a connecting element, to a wind turbine rotor blade and to a method for manufacturing a laminated structure.

[003] Wind turbines with rotor blades are widely known in the state of the art and are used to convert wind energy into electrical energy. In the region of a rotor blade root, the rotor blades typically comprise a rotor blade attachment region with a plurality of connecting elements integrated into the laminate. The connecting elements are bushings or comprise bushings through which the rotor blades are connected by means of fastening screws (threads) to a support ring of a so-called pitch bearing or to a component connected to the support ring, such as, for example, a wind turbine extender. The connecting elements may form part of a flange insert for attaching the rotor blade. Such a structure is known, for example, from international application WO 2015 / 124568 A1.

[004] Alternatively, such connecting elements are also used during the connection of rotor blade segments which, when arranged and mounted longitudinally, form a rotor blade. The bushings are then located in the laminate of a respective split flange of the rotor blade segments. The rotor blade segments Petition 870250081872, dated 11 / 09 / 2025, page 6 / 44 2 / 20 rotors are connected to each other via connecting elements by means of screws or by means of suitable intermediate pieces.

[005] An underlying objective of the invention is to provide a concept for a connecting element that contributes to a highly reliable fit of the connecting element into a surrounding laminate of a wind turbine rotor blade, wherein, in particular, the force transmission between a bushing of the connecting element and the surrounding laminate is optimized.

[006] According to the first aspect, a laminated structure for a flange connection of a wind turbine rotor blade is disclosed. The laminated structure comprises at least one connecting element comprising a bushing and a core element. A first end of the bushing has a bore hole with an internal thread adapted to accommodate a connecting bolt. A second end of the bushing has a bushing outlet with an internal recess, the internal recess being funnel-shaped. The core element comprises an inner portion, an intermediate portion and an outer portion. The outer portion tapers at an end opposite the inner portion and is, for example, adapted to be included in a wind turbine rotor blade, outside the bushing.The inner portion has a shape corresponding to the inner recess, which means that, for example, the inner portion tapers towards its inner end (the end that is inserted into the bushing outlet).

[007] A first layer of laminate is wrapped around the inner and middle portions of the core element. The wrapped core element is inserted into the inner recess with the inner portion so that the first layer of laminate is positioned between the core element and the bushing exit.

[008] The laminated structure described, which comprises the element Petition 870250081872, dated 11 / 09 / 2025, page 7 / 44 A 3 / 20 connection is a half-product configured to be incorporated into an intermediate laminated half-product, for example, a prefabricated flange insert, which is then used in a final laminate, for example, the wind turbine rotor blade housing. Alternatively, the described laminated structure is used directly for the manufacture of the final laminate, for example, the rotor blade housing. The described laminated structure, in particular the first laminate layer, is configured to be impregnated with resin during the manufacturing process of a wind turbine rotor blade. Typically, a set of connecting elements is used for the intermediate laminated half-product and / or the final laminate.

[009] The inventor found that the laminated structure described above presents structural advantages with respect to the incorporation of the connecting element into the surrounding laminate of the wind turbine rotor blade, for example, the housing or flange. According to the invention, the first layer of laminate is arranged around the core element so that this first layer of laminate lies between the outer surface of the core element and the inner wall of the bushing outlet, wherein the first layer of laminate also covers (at least partially) the intermediate portion. Thus, a portion of the first layer of laminate lies inside the bushing and the other portion lies outside the bushing, being in contact with other layers of laminate. In other words, the inventive design of the connecting element provides an inner core laminate, wherein the first layer of laminate lines the wall of the inner recess of the bushing outlet, at least partially.

[0010] In a later production step, for example, if the connecting element is placed in a mold for the production of the wind turbine rotor blade or the intermediate laminated structure, as above, resin infusion occurs. In this process, the resin Petition 870250081872, dated 11 / 09 / 2025, page 8 / 44 4 / 20 impregnates the first layer of laminate and impregnates it before curing. In particular, since the first laminate also covers the intermediate portion of the core element, the resin can spread well inside the bushing outlet, i.e., inside the inner recess, and bonds the core element to the bushing from the inside.

[0011] The invention contributes to excellent load transfer between the bushing and a surrounding fiber composite material bonded to it, such as the final laminate, in the final curing state of the involved laminate and in the operating state of the rotor blade. Stress peaks or stiffness jumps between the bushing and the laminate at the bushing outlet, particularly at the interfaces or bonding regions, are avoided or reduced. This helps to minimize local overloads in the connecting element, such as at the outlet at the second end of the bushing. Thus, higher stresses can be compensated for in the bushing, especially in thin-walled areas at the bushing outlet. Consequently, cracks or ruptures in the bushing and overload of the bond between the laminate and the bushing are avoided. Overall, the invention allows for a design of the connecting element suitable for bonding and incorporation into other laminates.

[0012] The core element is made of a filler material, for example, a foam material or a fiber-reinforced cured material. For example, the core element is inserted into the bushing outlet at least until it touches a wall of the bushing (outlet), or into a screw fastening element, which is inserted into the inner recess before the core element. For example, such a screw fastening element ensures that no resin enters the threaded area of ​​the bushing and that the connecting screw does not penetrate the core element during screw assembly. Preferably, the core element is inserted into the inner recess as far as possible in order to obtain the maximum contact area between the first layer of la Petition 870250081872, dated 11 / 09 / 2025, page 9 / 44 5 / 20 mined and the wall of the inner recess bushing. Furthermore, air-filled cavities, for example, air pockets, which would be filled with pure resin during vacuum infusion, are avoided or at least reduced.

[0013] The bushing exit is the portion of the bushing that leads to the second end of the bushing. Funnel shape means that the wall thickness of the bushing exit tapers towards the second end, while the inner diameter of the inner recess increases towards the second end of the bushing. The bushing has, for example, a cylindrical configuration. For example, the following shapes are conceivable for the bushing exit: a conical shape, a champagne glass shape, hyperbolas, polynomials, exponential functions and combinations, as well as free shapes and grooves.

[0014] The first layer of laminate is at least wrapped around the inner and intermediate portions of the core element. Preferably, the entire sheath surface of the inner portion is covered with the first layer of laminate. The sheath surface of the intermediate portion may be covered totally or partially.

[0015] The intermediate portion and the outer portion of the core element are disposed outside the bushing.

[0016] The first layer of laminate (and this applies to all other layers of laminate to be described in this text) comprises one or more layers of fibers, for example, one or more fiber mats.

[0017] The outer portion of the core element tapers towards the outer end of the core element. For example, the outer portion is shaft-shaped. This contributes to an ideal fit of the connecting element into the surrounding laminate of the wind turbine rotor blade.

[0018] According to one embodiment, the outer portion is exempt Petition 870250081872, dated 11 / 09 / 2025, page 10 / 44 6 / 20 of the first layer of laminate. This contributes to a very good fit of the connecting element into the surrounding laminate of the wind turbine rotor blade.

[0019] According to one embodiment, a second layer of laminate is wrapped around the bushing and the core element. Preferably, the second layer of laminate covers the bushing (partially or completely) and the intermediate portion (partially or completely) of the core element, wherein the outer portion remains free of the first and second layers of laminate. Optionally, the outer portion may also be covered, at least partially, by the second layer of laminate. This further contributes to the functions and advantages mentioned above.

[0020] According to one embodiment, the first laminate layer and / or the second laminate layer are made of a dry fiber material comprising unidirectional fibers aligned in the direction of the load and infused with resin. This means, in particular, that the laminated structure is in a final assembly state, for example, it is contained in an intermediate medium-product, such as a prefabricated flange insert, or it is contained in the rotor blade of the final wind turbine produced.

[0021] According to the invention, the first layer of laminate is wrapped around the core element. The dry fiber material (also known as dry material) can adapt very effectively to the shape of the inner portion of the core element, which has a decreasing diameter towards the inner end, i.e., it tapers. Using dry material, it is possible to cover the entire surface of the inner portion of the core element to obtain a reliable and strong connection with the bushing after impregnation of the first layer of laminate with resin and its curing. The fibers of the first layer of laminate are preferably aligned in the direction of the acting load. Petition 870250081872, dated 11 / 09 / 2025, page 11 / 44 7 / 20 during operation. In other words, the first laminate layer preferably comprises unidirectional fibers oriented in the longitudinal direction (e.g., central axis) of the bushing, core element, or rotor blade, respectively. For example, the first laminate layer comprises a dry laminate layer, with an adapted shape, which, when wound around the core element, leads to an offset of the layer edges in the turns relative to the longitudinal axis. Alternatively, the first laminate layer may comprise more than one dry laminate layer, preferably two or three layers. The dry laminate layers are arranged one on top of the other with an offset of the edges relative to each other. The offset is at least 20 mm per layer.

[0022] According to one embodiment, the inner portion of the core element comprises a resin channel, the resin channel extending from an outer surface of the core element towards an end of the inner portion facing the first end of the bushing. The end of the inner portion is, for example, a tip of the core element being inserted into the bushing. By means of the resin channel, the flow of resin to the inner region of the inner recess can be improved in order to impregnate the entire first layer of laminate within the inner recess.

[0023] According to one embodiment, the resin channel is formed in a cross shape within the core element, in particular by transversely arranged slots. This makes the inner portion of the core element more flexible, so that it can be inserted into the bushing at the correct depth. Furthermore, this provides an even better distribution of the resin, as the channel allows a larger distribution area for the resin outside the core element, particularly in the tip region, so that the resin can impregnate the first layer of laminate. Petition 870250081872, dated 11 / 09 / 2025, page 12 / 44 8 / 20

[0024] According to one embodiment, a spacer element is at least partially disposed in the resin channel. The spacer element may be a flexible element, for example, an elastomer or a compressible foam material, which is fixed or pressed into the resin channel. Due to the flexibility of the material, on the one hand, the spacer element may be compressed by the core element during insertion into the bushing outlet and, on the other hand, may exert pressure against the core element, resulting in a better fit of the core element and the first laminate layer involved in the bushing outlet. Furthermore, the spacer element keeps the resin channel open during resin impregnation to ensure the distribution of the infused resin. In other words, the spacer element spreads the open resin channel or keeps it open for resin infusion.

[0025] According to one embodiment, the bushing outlet is at least partially roughened within the inner recess. This allows for good adhesion of the resin to the walls that define the inner recess.

[0026] According to one embodiment, the inner portion of the core element is inserted about 10 cm or more into the inner recess. For example, the inner portion covers at least 20% of the entire length of the core element.

[0027] According to a second aspect, a connecting element for a flange connection of a wind turbine rotor blade is described. The connecting element comprises a bushing and a core element. A first end of the bushing has a bore hole with an internal thread adapted to accommodate a connecting screw. A second end of the bushing has a bushing outlet with an internal recess, the internal recess being funnel-shaped. The core element comprises an inner portion, an intermediate portion, and an outer portion. The outer portion Petition 870250081872, dated 11 / 09 / 2025, page 13 / 44 9 / 20 taper at one end opposite the inner portion. The inner portion has a shape corresponding to the inner recess. A first layer of laminate is wrapped around the inner and intermediate portions of the core element. The wrapped core element is inserted into the inner recess with the inner portion so that the first layer of laminate is positioned between the core element and the bushing exit.

[0028] The connecting element enables the functions and advantages mentioned above. The modalities described above apply analogously.

[0029] According to a third aspect, a wind turbine rotor blade is disclosed, comprising a flange connection with a laminated structure according to any of the embodiments above. The laminated structure may be disposed at the root of the rotor blade to provide a flange connection to a hub or extender. Additionally or alternatively, the laminated structure may be disposed in a segment region of a rotor blade segment to provide a flange connection suitable for connecting the rotor blade segment to another rotor blade segment.

[0030] The wind turbine rotor blade enables the functions and advantages mentioned above. The modalities described above apply analogously.

[0031] The wind turbine rotor blade typically comprises several connecting elements, as described above, wherein the various connecting elements are arranged in the circumferential direction.

[0032] According to a fourth aspect, a method is disclosed for manufacturing a laminated structure for a flange connection of a wind turbine rotor blade. The method comprises the steps of: - to provide a bushing, the bushing comprising - in a first instance Petition 870250081872, dated 11 / 09 / 2025, page 14 / 44 10 / 20 bushing end - a probe hole with an internal thread adapted to accommodate a connecting screw, and - at a second end of the bushing - a bushing outlet with an internal recess, the internal recess being funnel-shaped, - to provide a core element, comprising an inner portion, an intermediate portion, and an outer portion, in which - - the inner portion has a shape corresponding to the shape of the inner recess, and - The outer portion tapers at an end opposite to the inner portion and is, for example, adapted to be included in a wind turbine rotor blade lamination outside the bushing. - to enclose a first layer of laminate around the inner and middle portions of the core element, - Insert the core element into the inner recess with the inner portion so that the first layer of laminate is positioned between the core element and the bushing outlet, and - infusing the first layer of laminate with resin and curing the resin.

[0033] The method enables the functions and advantages mentioned above. The embodiments described above apply analogously.

[0034] According to one embodiment, the method comprises the additional step of: - involving a second layer of laminate around the bushing and core element, wherein, in the infusion stage, both the first and second layers of laminate are infused with resin and subsequently cured.

[0035] According to one embodiment, the method comprises the additional step of embedding the connecting element between one or more additional laminate layers. These additional laminate layers form the laminate of a prefabricated flange insert or wind turbine rotor blade, for example, the casing. Petition 870250081872, dated 11 / 09 / 2025, page 15 / 44 11 / 20

[0036] According to one embodiment - before the stage of wrapping the first layer of laminate - an adhesive, for example, an adhesion agent, is applied to the surface of the inner portion of the core element to fix the first layer of laminate. For example, a spray adhesive is used.

[0037] With regard to the modalities of the above method, we refer to the functions and advantages described above.

[0038] Other advantages, attributes and further developments are presented by the following exemplary embodiments, which are explained together with the figures. The same elements or similar elements, or elements that act in the same way, are given the same reference numbers in the figures, where: Figure 1 shows a schematic representation of a wind turbine according to an example of an embodiment. Figure 2 shows a schematic representation of a wind turbine rotor blade. Fig. 3 shows a schematic representation of a flange insert for the rotor blade. Fig. 4 shows a cross-sectional view of a laminated structure according to an embodiment of the invention. Figures 5a to 5d show different cross-sectional views of the laminated structure according to Figure 4. Figures 6 and 7 show cross-sectional views of a laminated structure according to another embodiment of the invention. Fig. 8 shows a cross-sectional view of a laminated structure according to another embodiment of the invention. Fig. 9 shows a schematic drawing of the first layer of laminate, and Figure 10 shows a schematic flowchart of a method according to Petition 870250081872, dated 11 / 09 / 2025, page 16 / 44 12 / 20 with an embodiment of the invention.

[0039] Figure 1 shows a schematic view of a wind turbine 100, comprising a tower 102. The tower 102 is fixed to the ground by means of a foundation 104. At one end of the tower 102, opposite the ground, a nacelle 106 is rotatably mounted. The nacelle 106, for example, comprises a generator coupled to a rotor 108 by means of a rotor shaft (not shown). The rotor 108 comprises one or more rotor blades (of a wind turbine) 110, arranged in a rotor hub 112.

[0040] During operation, rotor 108 is driven by an airflow, for example, wind. This rotational motion is transmitted to the generator via the rotor shaft and, if necessary, a gearbox. The generator converts the kinetic energy of rotor 108 into electrical energy.

[0041] Figure 2 shows an example of a wind turbine rotor blade 110. The rotor blade 110 has the shape of a conventional rotor blade and has a rotor blade root area 114 facing the rotor hub 112. The rotor blade root area 114 typically has an essentially circular cross-section. The rotor blade root area 114 is followed by a transition area 116 and a rotor blade profile area 118. The rotor blade 110 has a pressure side 122 and an opposite suction side 124 with respect to a longitudinal extension direction 120 (also the main extension direction). The rotor blade 110 is essentially hollow inside.

[0042] In the root area of ​​rotor blade 114, a rotor blade connection end 126 is provided with a flange connection 128, by means of which rotor blade 110 is mechanically connected to a pitch bearing or to an extender.

[0043] The rotor blade 110 comprises a split area 130 where a rotor blade segment 132 is located at the base of the blade and a Petition 870250081872, dated 11 / 09 / 2025, page 17 / 44 13 / 20 rotor blade segment 134 located at the blade tip are connected to each other. For this purpose, segments 132 and 134 each comprise a connection area of ​​segment 136 and 138 (also connection ends). Rotor blade 110 is therefore a split or segmented rotor blade.

[0044] Typically, a flange insert 140 is provided for making the flange connection 128 at the connecting end of the rotor blade 126. Said flange insert 140 comprises an arched laminate 142 (for example, an inner laminate and an outer laminate), in which a multiplicity of connecting elements 116 with threaded bushings are incorporated, extending in the longitudinal extension direction 120. The bushings are, for example, metal bushings, in particular steel bushings. A semicircular segment is shown in Figure 3, which also shows an enlarged detailed cutout.

[0045] In a typical manufacturing process, the flange insert 140 is initially produced as a half-product or intermediate product, in which the connecting elements 144 are arranged in a circle at fixed distances adjacent to each other. Optionally, spacer elements are used to ensure the space between two adjacent connecting elements 144. The laminate 142, as well as the connecting elements 144, are subsequently hermetically sealed and infused with a matrix material, for example, epoxy resin. In a later step, the flange insert 140 is inserted, for example, into a master mold to produce the final rotor blade 110, i.e., the (half) housing of the rotor blade, and connected to other layers of laminate.

[0046] However, it is also conceivable that no flange insert 140 is provided and the connecting elements 144 are embedded directly into the rotor blade laminate layers 110, by Petition 870250081872, dated 11 / 09 / 2025, page 18 / 44 14 / 20 example, in rotor blade half-casings.

[0047] Similarly, the two rotor blade segments 132 and 134 are connected by means of such connecting elements 140 with or without flange inserts.

[0048] Note that the rotor blade configuration 110, being composed of the two rotor blade segments 132 and 134, is optional. It is also possible that the rotor blade 110 is not segmented along the longitudinal direction 120.

[0049] Figure 4 shows a cross-sectional view of a laminated structure 146 with a connecting element 144, according to one embodiment of the invention. For example, the laminated structure 146 shown is a cutout of the connecting end 136 of the first rotor blade segment 132 to connect it to the associated connecting end 138 of the second rotor blade segment 134. Alternatively, the laminated structure 146 is disposed in the root area of ​​the rotor blade 114.

[0050] The connecting element 144 comprises an essentially cylindrical metal bushing 148 and a separate core element 150. The bushing 148 has a first end 152 and a second end 154 on the opposite side. The first end 152 of the bushing 148 has a probe hole 156 with an internal thread 158 adapted to accommodate a connecting screw for connecting the connecting element 144 to a corresponding connecting element of the other rotor blade segment. The second end 154 has a bushing outlet 160 with an internal recess 162, the internal recess 162 being funnel-shaped. See the introductory description for more details. The core element 150 is made of polymer foam and – along a longitudinal axis 164 of the bushing 148 (or connecting element 144, respectively) – is composed of an inner portion 166, an intermediate portion 168 and an outer portion. Petition 870250081872, dated 11 / 09 / 2025, page 19 / 44 15 / 20 core element 170. The core element 150 has an inner end 172 and an opposite outer end 174. The outer portion 170 tapers (is tapered) at the outer end 174 and is adapted to be included in the surrounding laminate, for example, of a wind turbine rotor blade housing 110 or flange insert 140, as described. The inner portion 166 has a shape that corresponds to the inner recess 162.

[0051] A first layer of laminate 176 (see the inner line in bold) is wrapped around the core element 150, in particular, entirely around the inner portion 166 and the intermediate portion 168. The outer portion 170 is free from the first layer of laminate 176.

[0052] The wound core element 150 is inserted into the inner recess 162 with the inner portion 166 such that the first layer of laminate 176 is disposed between the core element 150 and the bushing outlet 160. The intermediate portion 168 and the outer portion 170 of the core element 150 extend outward from the bushing outlet 160. The core element 150 is inserted into the bushing outlet 160 until its inner end 172 abuts, for example, against a screw fastening element 178. The core element 150 is inserted approximately 10 cm or more into the inner recess 162.

[0053] In addition, a second layer of laminate 180 is wrapped around the entire bushing 148 and the entire core element 150 (see bold line). The second layer of laminate 180 is then wrapped over the first layer of laminate 176 in the central portion 168 of the core element 150 (see also figure 5c).

[0054] Finally, the connecting element 144 and its first and second laminate layers 176 and 180 are incorporated into third laminate layers 182, for example, the final laminate, as described above. Petition 870250081872, dated 11 / 09 / 2025, page 20 / 44 16 / 20

[0055] All laminate layers 176, 180 and 182 comprise one or more fiber layers (fiber mats), which are infused with resin after winding during a resin infusion step in a subsequent manufacturing process. Note that the surface of the inner recess 162 of the bushing outlet 160 is roughened for better resin adhesion. In addition, adhesive 190, for example by spraying, may be applied at least to the surface of the inner portion 166 (optionally also to the intermediate portion 168) before the first laminate layer 176 is wound onto the core element 150.

[0056] Figures 5a to 5d show different cross-sectional views of the connecting element 144 of Figure 4 along the longitudinal axis 164. From these cross-sectional views, the arrangement of the connecting element and the various laminate layers 176, 180 and 182 is visible, particularly in relation to the radial direction along the longitudinal axis 164.

[0057] The laminated structure 146 described above and its connecting element 144 enable the functions and advantages mentioned in the introductory part.

[0058] Figures 6 and 7 refer to another embodiment of the invention. The laminated structure 146 shown is the same as that described above, therefore the same reference signs are used and no further description is necessary. However, the core element 150 additionally comprises a resin channel 184 in the inner portion 166, which extends from an outer surface 186 of the core element 150 towards the inner end 172. At the inner end 172, a flexible spacer element 188 is inserted into the resin channel 184. As can be seen in Figure 7, which shows the cross-sectional view EE of Figure 6, the resin channel 184, as well as the spacer element 188, are formed in a cross shape. Petition 870250081872, dated 11 / 09 / 2025, page 21 / 44 17 / 20

[0059] Figure 8 shows a cross-sectional view of the laminated structure 146, according to another embodiment of the invention. The attributes and reference signs described above apply analogously, unless otherwise indicated below. The core element 150 is wrapped in the first layer of laminate 176 and inserted into the bushing exit 160 of the bushing 148. The first layer of laminate 176 has a predefined shape (see, for example, Figure 9) which causes an edge (or a portion of the edge) of the layer 176 to be displaced along the turns when the core element is wrapped. The first layer of laminate 176 is wrapped around the core material in such a way that the unidirectional fibers 192 (shown schematically in Figures 8 and 9) run essentially along the longitudinal axis 164 of the core element 150 or the bushing 148, respectively.

[0060] Figure 9 shows the shape of the first layer of laminate 176. The dimensions may vary depending on the shape of the core element 150. The first layer of laminate 176 (here reference is made to one layer, although multiple layers may be provided) has a specific cut when unwound or extended that does not correspond to a pure rectangle. Instead, when viewed from left to right in the figure, the first layer of laminate 176 shown is formed by a rectangular section 194, a parallelogram-shaped section 195 (which optionally tapers from left to right), and again a rectangular section 196. The special shape of the trim of the first laminate (dry layer) ensures that the unidirectional fibers 192 remain in longitudinal order.However, the shape of the first layer of laminate 176 ensures an oblique winding, where the edges 198 of each turn of the parallelogram-shaped section are oblique to the longitudinal axis 164, with an offset of at least 20 mm between them. The edges. Petition 870250081872, dated 11 / 09 / 2025, page 22 / 44 18 / 20 200 and 202 of the rectangular sections 194 and 196 are perpendicular to the longitudinal axis 164 (see also Fig. 8). Furthermore, the specific shape ensures a wrinkle-free enclosure of the core element 150.

[0061] Figure 10 shows a schematic flowchart of a method according to an embodiment of the invention. The method describes the manufacturing steps of the laminated structure 146, as described above, for a flange connection of a wind turbine rotor blade 110.

[0062] In a first stage S1, bushing 148 is supplied.

[0063] In a second stage S2, the core element 150 is provided.

[0064] In a third stage S3, the first layer of laminate 176 is wrapped around the inner portion 166 and at least part of the intermediate portion 168 of the core element 150.

[0065] In a fourth stage S4, the core element 150 is inserted into the inner recess 162 with the inner portion 166 so that the first layer of laminate 176 is disposed between the core element 150 and the bushing outlet 160, as described above.

[0066] In a fifth stage S5, the first layer of laminate 176 is infused with resin and the resin cures.

[0067] The method provides the advantages and functions described.

[0068] The following steps can be carried out as described in the introductory section or in the sub-claims. Reference signs 100 wind turbine 102 tower 104th Foundation 106 nacelle 108 rotor Petition 870250081872, dated 11 / 09 / 2025, page 23 / 44 19 / 20 rotor blade rotor hub rotor blade root area transition area profile area longitudinal direction pressure side suction side rotor blade connection end flange connection split area first rotor blade segment second rotor blade segment first connection end second connection end laminated flange insert connection element laminated structure bushing core element first end second end bore hole internal thread bushing outlet internal recess longitudinal shaft internal portion intermediate portion Petition 870250081872, dated 11 / 09 / 2025, page 24 / 44 20 / 20 outer portion inner end outer end first laminate layer screw retaining element second laminate layer third laminate layer resin channel outer surface adhesive spacer element unidirectional fibers rectangular section parallelogram-shaped section rectangular section edge edge edge step Petition 870250081872, dated 11 / 09 / 2025, page 25 / 44

Claims

1 / 5 CLAIMS 1. A laminated structure (146) for a flange connection of a wind turbine rotor blade (110) with at least one connecting element (144) comprising a bushing (148) and a core element (150), CHARACTERIZED in that - a first end (152) of the bushing (148) has a bore hole (156) with an internal thread (158) adapted to accommodate a connecting bolt, - a second end (154) of the bushing (148) has a bushing outlet (160) with an internal recess (162), the internal recess (162) being funnel-shaped, - the core element (150) comprises an inner portion (166), an intermediate portion (168) and an outer portion (170), wherein - - the outer portion (170) tapers at one end (174) opposite the inner portion (166), - - the inner portion (166) has a shape corresponding to the inner recess (162),- a first layer of laminate (176) is wound around the inner portion (166) and the intermediate portion (168) of the core element (150), and - the wound core element (150) is inserted into the inner recess (162) with the inner portion (166) so that the first layer of laminate (176) is disposed between the core element (150) and the bushing outlet (160).

2. Laminated structure (146), according to claim 1, CHARACTERIZED in that the outer portion (170) is free from the first layer of laminate (176).

3. Laminated structure (146), according to claim 1 or 2, CHARACTERIZED in that it comprises a second layer of laminate (180) wrapped around the bushing (148) and the core element (150).

4. Laminated structure (146), according to claim 3, CHARACTERIZED in that the second layer of laminate (180) covers the bushing (148) and the intermediate portion (168) of the core element (150).

5. Laminated structure (146), according to claim 4, CHARACTERIZED in that the second layer of laminate (180) is rolled onto the first layer of laminate (176), in the intermediate portion (168) of the core element (150).

6. Laminated structure (146), according to any of the preceding claims, CHARACTERIZED in that the first layer of laminate (178) and / or the second layer of laminate (180) are made of a dry fiber material and infused with resin.

7. Laminated structure (146), according to any of the preceding claims, CHARACTERIZED in that the inner portion (166) of the core element (150) comprises a resin channel (184), the resin channel (1894) extending from an outer surface (186) of the core element (150) towards an end of the inner portion (166) facing the first end (152) of the bushing (148).

8. Laminated structure (146), according to claim 7, CHARACTERIZED in that the resin channel (184) is formed in a cross shape within the core element (150).

9. Laminated structure (146), according to claim 7 or 8, CHARACTERIZED in that a spacer element (188) is at least partially disposed in the resin channel (184).

10. Laminated structure (146), according to any of the preceding claims, CHARACTERIZED in that the bushing outlet (160) is at least partially rough within the inner recess (162).

11. Laminated structure (146), according to any of the preceding claims, CHARACTERIZED in that the inner portion (166) of the core element (150) is inserted about 10 cm or more into the inner recess (162).

12. Connecting element (144) for a flange connection of a wind turbine rotor blade (110), CHARACTERIZED in that it comprises a bushing (148) and a core element (150), wherein - a first end (152) of the bushing (148) has a bore hole (156) with an internal thread (158) adapted to accommodate a connecting screw, - a second end (154) of the bushing (148) has a bushing outlet (160) with an internal recess (162), the internal recess (162) being funnel-shaped, - the core element (150) comprises an inner portion (166), an intermediate portion (168) and an outer portion (170), wherein - - the outer portion (170) tapers at an end opposite to the inner portion (166), - - the inner portion (166) has a shape corresponding to inner recess (162), - a first layer of laminate (176) is wrapped around the inner portion (166) and the intermediate portion (168) of the core element (150),and - the wound core element (150) is inserted into the inner recess (162) with the inner portion (166) so that the first layer of laminate (176) is disposed between the core element (150) and the bushing outlet (160). Petition 870250081872, dated 11 / 09 / 2025, page 28 / 44 4 / 5, 13. Wind turbine rotor blade, CHARACTERIZED in that it comprises a flange connection with a laminated structure (146), as defined in any one of claims 1 to 11.

14. Method for manufacturing a laminated structure (146) for a flange connection of a wind turbine rotor blade (110), CHARACTERIZED in that it comprises the steps of: - providing a bushing (148), the bushing (148) comprising - at a first end of the bushing (152) - a bore hole (156) with an internal thread (158) adapted to accommodate a connecting bolt, and - at a second end of the bushing (154) a bushing outlet (160) with an internal recess (162), the internal recess (162) having the shape of a funnel, - providing a core element (150), comprising an inner portion (166), an intermediate portion (168) and an outer portion (170), wherein - - the inner portion (166) has a shape corresponding to the shape of the inner recess (162), and - - the outer portion (170) tapers at an end opposite the inner portion (166),- wrap a first layer of laminate (176) around the inner portion (166) and at least part of the intermediate portion (168) of the core element (150), - insert the core element (150) into the inner recess (162) with the inner portion (166) so that the first layer of laminate (176) is disposed between the core element (150) and the bushing outlet (160), and - infuse the first layer of laminate (176) with resin and cure it. Petition 870250081872, dated 11 / 09 / 2025, page 29 / 44 5 / 5, 15. Method according to claim 14, CHARACTERIZED in that it comprises the additional step of - wrapping a second layer of laminate (180) around the bushing (148) and core element (150) and in which, in the infusion step, both the first and second layers of laminate (176, 180) are infused with resin and subsequently cured.

16. Method, according to claims 14 or 15, CHARACTERIZED in that it comprises the additional step of embedding the connecting element (144) between one or more additional laminates.

17. Method, according to any one of claims 14 to 16, CHARACTERIZED in that - before the step of wrapping the first layer of laminate - the adhesive (190) is applied to the surface of the inner portion of the core element (150) for fixing the first layer of laminate. Petition 870250081872, dated 11 / 09 / 2025, pp. 30 / 44

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