A method of manufacturing wind turbine rotor blade component with embedded spacer

Abstract

A method of manufacturing a wind turbine rotor blade component (36), the method comprising the steps of:-providing a spacer (76) comprising a core member (10) and a sleeve (12), where the core member (10) comprises a longitudinal direction (14), a circumferential surface (16), a leading end (18) and a trailing end (20), and the sleeve (12) comprises a release layer (22), wherein the sleeve (12) covers the circumferential surface (16) and the rear end (20) of the core member (10) and is attached to the rear end (20) of the core member (10); -arranging the spacer (76) together with the reinforcing fibres and the matrix material in a mould (84); and curing the matrix material such that the spacer (76) is embedded in the fiber-reinforced composite material (34).

Description

Technical Field

[0001] The present invention relates to a method of manufacturing a wind turbine rotor blade component including a placeholder. The placeholder is embedded in a fiber-reinforced composite material of the wind turbine rotor blade component so that the placeholder can be removed later, thereby forming a cavity in the fiber-reinforced composite material. The cavity can be used in particular for inserting and fastening a joining element to the wind turbine rotor blade component. Background Art

[0002] Such a method is known from document WO 2022 / 096497 A1. To ensure that the placeholder can be removed from the fiber-reinforced composite material, the known method proposes using a placeholder having a non-adhesive surface (including PTFE material) or an outer layer (including a release agent, a sacrificial material or a release layer). Summary of the Invention

[0003] Based on this, the object of the present invention is to provide an improved method and an improved placeholder that make it even easier to form a cavity with desired surface characteristics.

[0004] This object is solved by the method of claim 1 and by the placeholder of claim 12. Preferred aspects are given in the dependent claims.

[0005] The method of manufacturing a wind turbine rotor blade component includes the following steps:

[0006] Providing a placeholder including a core member and a sleeve, wherein the core member includes a longitudinal direction, a circumferential surface, a front end and a rear end, and the sleeve includes a release layer, wherein the sleeve covers the circumferential surface and the rear end of the core member and is attached to the rear end of the core member;

[0007] Arranging the placeholder together with reinforcing fibers and a matrix material in a mold;

[0008] Curing the matrix material so that the placeholder is embedded in the fiber-reinforced composite material.

[0009] A wind turbine rotor blade component can be any component of a wind turbine rotor blade, in particular a shell component such as a half-shell, spar, spar cap, or a longitudinal section of any of these wind turbine rotor blade components. A wind turbine rotor blade component can also be a connecting component that is intended to be used as a root connection for connecting a wind turbine rotor blade to the hub of a wind turbine rotor or as a connecting component for connecting a wind turbine rotor blade section to another rotor blade section. The fastening of the wind turbine rotor blade to the hub or the fastening of the wind turbine rotor blade sections to each other can be achieved by means of joining elements (in particular sleeves, such as sleeves with threaded holes) and / or bolts. When the placeholders embedded in the fiber-reinforced composite material of the wind turbine rotor blade component are removed and replaced with joining elements, these joining elements are anchored in the wind turbine rotor blade component. The longitudinal direction of the placeholders of the wind turbine rotor blade component can correspond to the longitudinal direction of the wind turbine blade component and ultimately to the longitudinal direction of the wind turbine blade using the wind turbine rotor blade component.

[0010] A wind turbine rotor blade component can include a mating surface that will contact / interface with an adjacent component such as a wind turbine rotor blade hub or another wind turbine rotor blade component or section. The placeholder can be embedded in the fiber-reinforced composite material such that it is accessible from the outside, in particular such that the placeholder and / or more specifically the front end of the placeholder is arranged at the mating surface. The mating surface can be arranged substantially perpendicular to the longitudinal direction of the placeholder and / or the wind turbine rotor blade component. The placeholder can have any suitable shape, such as cylindrical or conical, so that it corresponds to the shape of the joining element that will later be used to replace the placeholder.

[0011] The manufacturing of the wind turbine rotor blade component is carried out at least in part in a mold. The shape and dimensions of the mold depend on the type of wind turbine rotor blade component. The mold can have a forming surface at which the mating surface of the wind turbine rotor blade component is formed. It can have another forming surface that corresponds to the aerodynamic surface of the wind turbine rotor blade component. An open mold or a closed mold can be used.

[0012] The reinforcing fibers can be arranged in layers in the mold. The reinforcing fibers can include any suitable fiber type, such as glass fibers or carbon fibers, or a mixture of these fibers, and can also be combined with any other fiber type. The reinforcing fibers can be dry and / or pre-impregnated with a matrix material. If dry reinforcing fibers are placed in the mold, any suitable process can be used to add the matrix material, such as by hand addition like in traditional hand lay-up techniques, by vacuum infusion, or by resin injection. The matrix material can be, for example, polyester or epoxy resin.

[0013] The placeholder can be positioned in the mold such that its front end is arranged at the joining surface. For this purpose, the mold can have positioning means for positioning the placeholder. The positioning means can in particular be arranged at the molding surface of the mold corresponding to the joining surface. For example, the placeholder can have a threaded hole, and the mold can have a flange with a through-hole, so that the placeholder can be fixed in place with a bolt guided through the through-hole and screwed into the threaded hole of the placeholder. In an alternative or additionally, the placeholder can be fixed in place by means of other elements placed in the mold, in particular by reinforcing fibers and / or a foam core placed in the mold. The core member of the placeholder can be made of a metal, in particular steel or aluminum. However, other materials with sufficient stiffness and strength can also be used.

[0014] After the matrix material has cured, the reinforcing fibers and the cured matrix material (and optionally any other materials positioned in the mold) form a fiber-reinforced composite material in which the placeholder is embedded. This means that at least a large part of the surface of the placeholder, in particular the part corresponding to its entire circumferential surface or a large part thereof, will be covered by the fiber-reinforced composite material.

[0015] The advantage of the present invention is that by removing the placeholder and replacing it with a joining element, the joining element can be integrated into the wind turbine rotor blade component very easily. For this purpose, the placeholder can be removed from the fiber-reinforced composite material simply by pulling the placeholder in a direction away from the rear end of the placeholder. The sleeve with the release layer prevents the matrix material from forming a firm bond with the core member of the placeholder, which is a prerequisite for being able to remove the core member in an easy manner. At the same time, the specific arrangement of the sleeve and its fixation to the rear end of the core member have the effect that the sleeve will peel off from the wall of the fiber-reinforced composite material surrounding the placeholder when the core member is pulled out of the fiber-reinforced composite material, so that the sleeve will be removed from the fiber-reinforced composite material together with the core member as a whole. Ideally, the cavity formed in the fiber-reinforced composite material thereby will have a clean surface and no sleeve residues. This clean surface is very suitable for obtaining a firm bond between the wall of the cavity and the joining element adhered thereto.

[0016] The wind turbine rotor blade component can be provided with any number of placeholders, for example, only one, two, three, or more than three placeholders. Each placeholder is embedded in the fiber-reinforced composite material and can be removed from the fiber-reinforced composite material as described above.

[0017] In one aspect, the step of providing the placeholder includes applying a release agent to at least the circumferential surface of the core member. The release agent may also be applied to the surface of the core member at the rear end of the core member. The release agent reduces the force required to pull the core member out of the fiber-reinforced composite material because it allows the core member to slide along the inner surface of the sleeve. This also helps to achieve a smooth peeling process of the sleeve from the fiber-reinforced composite material.

[0018] In one aspect, the step of providing the placeholder includes the step of wrapping a release layer around the circumferential surface of the core member. This is a simple way to form a tightly fitting sleeve covering the entire circumferential surface. If desired, the release layer may be fixed by means of an adhesive (such as an adhesive tape or an adhesive spray), which is particularly applied to the outer surface of the segments of the release layer that come into contact with the adjacent inner surface of another segment of the release layer.

[0019] In one aspect, the step of providing the placeholder further includes the step of folding a segment of the release layer that extends beyond the rear end of the core member in the longitudinal direction onto the rear end. This segment (or any number of corresponding segments) of the release layer may also be fixed by means of an adhesive.

[0020] In one aspect, the step of providing the placeholder includes the step of providing a sleeve by forming a release layer to have a sock shape and the subsequent step of inserting the core member into the sleeve. The sock shape means that the sleeve is substantially formed to resemble a tube with a closed end, such that once the core member is inserted into the sleeve, the sleeve will automatically cover the circumferential surface and the rear end of the core member. Any suitable technique may be used to make the release layer assume the sock shape, including bonding or stitching the segments of the release layer to each other.

[0021] In one aspect, the sleeve is attached to the rear end of the core member by means of a clamping element that applies a clamping force to the release layer of the sleeve. This has been found to be a very simple and reliable solution for attaching the sleeve, especially since the clamping element is easy to apply to any release layer and the clamping force will be almost unaffected by the specific characteristics (such as in terms of material and thickness) of the release layer. The clamping element may be arranged such that the clamping force presses the release layer against the rear end of the core member.

[0022] In one aspect, the clamping element is the head of a screw or a washer placed under the head of the screw, and the screw is screwed into a threaded hole provided at the rear end of the core member. According to this aspect, the release layer may be placed between the rear end of the core member and the head of the screw or the washer, respectively. By means of the screw, a large clamping force may be applied, thereby securely attaching the sleeve to the core member. In addition, the screw and / or the washer may be used multiple times, especially if a release agent is applied to the screw and / or the washer before these elements come into contact with the matrix material.

[0023] In one aspect, the clamping element has a circumferential lip that contacts the release layer. The lip can be arranged at the bottom side of the clamping element, for example, provided in a circumferential groove. The lip provides a well-defined contact area for holding the release layer. The lip can also prevent matrix material from entering the bore of the threaded connection and blocking the threaded connection.

[0024] In one aspect, the method includes an additional step:

[0025] Connect a pulling tool to the fastening element of the core member.

[0026] The fastening element is particularly an opening located at the front end of the core member, such as a threaded hole for assembling the core member to the flange of a mold. Alternatively, the fastening element can extend beyond the front end of the core member, such as a hook, lug, or pin.

[0027] By means of the pulling tool, a required pulling force is particularly easily applied to the core member to pull it together with the sleeve out of the surrounding fiber-reinforced composite material.

[0028] In one aspect, the method includes an additional step:

[0029] Pull the core member longitudinally towards the front end out of the fiber-reinforced composite material so that the sleeve is peeled off from the fiber-reinforced composite material and a cavity is formed in the fiber-reinforced composite material.

[0030] As already explained above, this additional step will form a cavity in the fiber-reinforced composite material that is very suitable for fastening a joining element thereto.

[0031] In one aspect, the method includes an additional step:

[0032] Insert and fasten a joining element into the cavity, where the joining element is particularly a bushing with a threaded hole.

[0033] The joining element can be particularly fastened in the cavity by means of an adhesive.

[0034] The above problem is also solved by the placeholder of claim 12. The placeholder is for embedding in a fiber-reinforced composite material of a wind turbine rotor blade component and includes:

[0035] A core member that includes a longitudinal direction, a circumferential surface, a front end, and a rear end, and

[0036] A sleeve that includes a release layer, where the sleeve covers the circumferential surface and the rear end of the core member and is attached to the rear end of the core member.

[0037] This placeholder is intended to be used in a method having the features of any one of claims 1 to 11. Regarding the features and advantages of this placeholder, reference is made to the above explanations related to this method, which also apply to this placeholder.

[0038] The placeholder can be adjusted according to the various aspects of the above method. For example, the placeholder can include at least a release agent applied to the circumferential surface of the core member. The release layer can be wrapped around the circumferential surface of the core member. The section of the release layer extending beyond the rear end of the core member in the longitudinal direction can be folded onto the rear end. The release layer can have a sock shape. The sleeve can be attached to the rear end of the core member by means of a clamping element that applies a clamping force to the release layer of the sleeve. The clamping element can be the head of a screw or a washer placed under the head of the screw, and the screw is screwed into a threaded hole provided at the rear end of the core member. The clamping element can have a circumferential lip in contact with the release layer. The core member can include a fastening element for connecting a pulling tool to the core member, and in particular, the fastening element can be an opening located at the front end of the core member, or a connecting device extending beyond the front end of the core member, such as a hook, lug or pin.

[0039] In one aspect, a wind turbine rotor blade component includes a fiber-reinforced composite material and a placeholder having the features of claim 12, wherein the placeholder is embedded in the fiber-reinforced composite material.

[0040] In one aspect, the placeholder is embedded in the fiber-reinforced composite material such that when the core member is pulled out of the fiber-reinforced composite material in the longitudinal direction towards the front end, the sleeve is peeled off from the fiber-reinforced composite material and a cavity is formed in the fiber-reinforced composite material. Description of the Drawings

[0041] Hereinafter, the present invention will be explained in more detail based on the embodiments shown in the drawings.

[0042] Figure 1 A wind turbine rotor blade component with an embedded placeholder is shown in a schematic longitudinal section;

[0043] Figure 2 The arrangement when pulling out the placeholder is shown Figure 1 ;

[0044] Figure 3 The placeholder is shown in two schematic diagrams;

[0045] Figure 4 Another placeholder is shown in two schematic diagrams;

[0046] Figure 5 The core member of yet another placeholder is shown in a longitudinal section;

[0047] Figure 6A wind turbine rotor blade is shown in a schematic perspective view;

[0048] Figure 7 A wind turbine rotor blade having two longitudinal sections is shown, each longitudinal section having a wind turbine rotor blade connection component;

[0049] Figure 8 A wind turbine rotor blade component arranged at the root of the wind turbine rotor blade is shown. Detailed Description

[0050] Figure 1 A placeholder is shown in cross-section, which includes a core member 10 and a sleeve 12. The core member 10 has a longitudinal direction 14, a circumferential surface 16, a front end 18, and a rear end 20. The sleeve 12 consists of a sock-shaped release layer 22. The sleeve covers the entire circumferential surface 16 of the core member 10 as well as the rear end 20.

[0051] The core member 10 further includes a fastening element, namely an opening 24 having an internal thread 26. The opening 24 is arranged at the front end 18 of the core member 10. At its rear end 20, the core member has a threaded hole 52 into which a screw 28 is inserted. The screw 28 has a screw head 30 and serves as a clamping element that applies a clamping force on the release layer 22 of the sleeve 12. A section of the release layer 22 covering the rear end 18 is arranged between the underside of the screw head 30 and the rear end 20 of the core member 10.

[0052] The placeholder is embedded in a fiber-reinforced composite material 34 of the wind turbine rotor blade component 36. The wind turbine rotor blade component 36 has a mating surface 38 flush with the front end 18 of the core member 10. The sleeve 12 extends beyond the front end 18 of the core member 10, so there is no direct contact between the core member 10 and the surrounding fiber-reinforced composite material 34. The fiber-reinforced composite material 34 is arranged below, above, and to the right of the placeholder. Only the front end 18 of the core member is accessible from the outside. The wind turbine rotor blade component 36 includes a wedge-shaped foam core 40 adjacent to the rear end 20 of the core member 10 and embedded in the fiber-reinforced composite material 34.

[0053] For manufacturing Figure 1 the wind turbine rotor blade component 36, a placeholder is provided and arranged in a mold (not shown) together with reinforcing fibers and a matrix material. Then the matrix material is allowed to cure so that the placeholder is embedded in the fiber-reinforced composite material 34.

[0054] Figure 2 Shown is Figure 1arrangement while pulling the core member 10 in the direction of arrow 42 from the surrounding fiber-reinforced composite material 34 towards the front end 18. This can be accomplished by fastening a pulling tool to the opening 24. It can be seen that the release layer 22 remains attached to the rear end 20. The core member 10 slides out of the sleeve 12, and the sleeve 12 is peeled off from the wall 44 of the cavity 46 formed in the fiber-reinforced composite material 34.

[0055] Figure 3 Another placeholder is shown, in longitudinal section on the left side of the figure and in a view of the rear end 20 on the right side of the figure. This placeholder is similar to the one shown in Figure 1 and Figure 2 The sleeve 12 has been formed by wrapping the release layer 22 around the circumferential surface 16 of the core member 10. The segment 48 of the release layer 22 that extends beyond the rear end 20 of the core member 10 has been folded onto the rear end 20. They are attached to the rear end by means of the screw head 30 of the screw 28.

[0056] Figure 4 Another placeholder is shown, in longitudinal section on the left side of the figure and in a view of the rear end 20 on the right side of the figure. This placeholder is similar to the one shown in Figure 1 and Figure 2 It is similar to the placeholder shown in Figure 3 The difference from the placeholder shown in

[0057] Figure 5 The core member 10 of yet another placeholder is shown only in longitudinal section. The core member 10 has a longitudinal direction 14, a circumferential surface 16, a front end 18, and a rear end 20. The core member 10 further includes an opening 24 that has an internal thread 26 and serves as a fastening element for attaching the core member to a mold flange and / or for assembling a pulling tool (not shown). The opening 24 is arranged at the front end 18 of the core member 10. At its rear end 20, the core member 10 has a threaded hole 52 into which the screw 28 is inserted. The screw 28 has a screw head 30. A large-diameter washer 50 is placed below the screw head 30 and can be pressed against the rear end 18 for clamping a segment (not shown) of the sleeve 12 to the rear end 20.

[0058] A circumferential groove 54 is formed at the bottom side of the washer 50, and the circumferential groove can accommodate an O-ring 55 that serves as a lip for clamping the sleeve 12 and for forming a seal between the rear end 20 and the washer 50.

[0059] Figure 6Shows a wind turbine rotor blade 56 having a longitudinal axis 58, an aerodynamic profile 60, a blade tip 62, and a blade root 64. The wind turbine rotor blade 56 is divided into two sections, namely an inner section 66 containing the blade root 64 and an outer section 68 containing the blade tip 62. The two sections 66 and 68 are joined to each other at a dividing plane 70.

[0060] Figure 7 Is shown in another schematic diagram Figure 6 Of the wind turbine rotor blade. The two sections 66, 68 are drawn at a distance from each other. Each blade section has a mating surface 72. Each of the sections 66, 68 contains a wind turbine rotor blade connection member 74 that faces the dividing plane 70 and forms the corresponding mating surface 72. In each wind turbine rotor blade connection member 74, three placeholders 76 are embedded.

[0061] Figure 8 Shows the manner in which the method is applied at the wind turbine rotor blade root 64. This view points to the mating surface 72 of the wind turbine blade root 64, which is adapted to be connected to the wind turbine rotor hub. The wind turbine blade root 64 is shown located in a mold 84 and contains a fiber-reinforced composite material 34 having a plurality of inner layers 80 and a plurality of outer layers 82 of fiber material. A foam core 78 is placed on top of the outer layer 82, and placeholders including a core member 10 and a sleeve 12 are arranged between each pair of foam cores. Each core member 10 includes an opening 24 for fastening a pulling tool.

[0062] List of reference numerals

[0063] 10 Core member

[0064] 12 Sleeve

[0065] 14 Longitudinal direction

[0066] 16 Circumferential surface

[0067] 18 Front end

[0068] 20 Rear end

[0069] 22 Release layer

[0070] 24 Opening

[0071] 26 Internal thread

[0072] 28 Screw

[0073] 30 Screw head

[0074] 34 Fiber-reinforced composite material

[0075] 36 Wind turbine rotor blade component

[0076] 38 Joint surface

[0077] 40 Foam core

[0078] 42 Arrow (pulling direction)

[0079] 44 Wall

[0080] 46 Cavity

[0081] 48 Segment of release layer

[0082] 50 Washer

[0083] 52 Threaded hole

[0084] 54 Circumferential groove

[0085] 55 O-ring

[0086] 56 Wind turbine rotor blade

[0087] 58 Longitudinal axis

[0088] 60 Aerodynamic profile

[0089] 62 Blade tip

[0090] 64 Blade root

[0091] 66 Inner section

[0092] 68 Outer section

[0093] 70 Split plane

[0094] 72 Joint surface

[0095] 74 Wind turbine rotor blade connection component

[0096] 76 Spacer

[0097] 78 Foam core

[0098] 80 Inner layer

[0099] 82 Outer layer

[0100] 84 Mold

Claims

1. A method of manufacturing a wind turbine rotor blade component (36), the method comprising the steps of: Providing a placeholder (76) comprising a core member (10) and a sleeve (12), wherein the core member (10) includes a longitudinal direction (14), a circumferential surface (16), a front end (18) and a rear end (20), and the sleeve (12) includes a release layer (22), wherein the sleeve (12) covers the circumferential surface (16) and the rear end (20) of the core member (10), and is attached to the rear end (20) of the core member (10); Arranging the placeholder (76) together with reinforcing fibers and a matrix material in a mold (84); Curing the matrix material such that the placeholder (76) is embedded in a fiber-reinforced composite material (34).

2. The method according to claim 1, wherein the step of providing the placeholder (76) includes applying a release agent to at least the circumferential surface (16) of the core member (10).

3. The method according to claim 1 or 2, wherein the step of providing the placeholder (76) includes the step of wrapping the release layer (22) around the circumferential surface (16) of the core member (10).

4. The method according to claim 3, wherein the step of providing the placeholder (76) further includes the step of folding a segment (48) of the release layer (22) that extends beyond the rear end (20) of the core member (20) along the longitudinal direction (14) onto the rear end (20).

5. The method according to claim 1 or 2, wherein the step of providing the placeholder (76) includes the step of providing the sleeve (12) by forming the release layer (22) to have a sock shape and the subsequent step of inserting the core member (10) into the sleeve (12).

6. The method according to any one of claims 1 to 5, wherein the sleeve (12) is attached to the rear end (20) of the core member (10) by means of a clamping element that applies a clamping force to the release layer (22) of the sleeve (12).

7. The method according to claim 6, wherein the clamping element is a head (30) of a screw (28) or a washer (50) placed under the head (30) of the screw (28), and the screw (28) is screwed into a threaded hole (52) provided at the rear end (20) of the core member (10).

8. The method according to claim 6 or 7, wherein the clamping element has a circumferential lip that contacts the release layer (22).

9. The method according to any one of claims 1 to 8, the method comprising the following additional step: Connecting a pulling tool to a fastening element of the core member (10).

10. The method according to any one of claims 1 to 9, the method comprising the following additional step: Pull the core member (10) out of the fiber-reinforced composite material (34) along the longitudinal direction (14) towards the front end (18), such that the sleeve (12) is peeled off from the fiber-reinforced composite material (34) and a cavity (46) is formed in the fiber-reinforced composite material (34).

11. The method according to claim 10, wherein the method comprises the following additional steps: Insert and fasten a joining element into the cavity, wherein the joining element is in particular a bushing with a threaded hole.

12. A placeholder (76) for being embedded in a fiber-reinforced composite material (34) of a wind turbine rotor blade component (36), the placeholder (76) comprising: A core member (10), the core member including a longitudinal direction (14), a circumferential surface (16), a front end (18) and a rear end (20), and A sleeve (12), the sleeve including a release layer (22), wherein the sleeve (12) covers the circumferential surface (16) and the rear end (20) of the core member (10) and is attached to the rear end (20) of the core member (10).

13. A wind turbine rotor blade component (36) comprising a fiber-reinforced composite material (34) and a placeholder (76) having the features of claim 12, wherein the placeholder (76) is embedded in the fiber-reinforced composite material (34).

14. The wind turbine rotor blade component (36) according to claim 13, wherein the placeholder (76) is embedded in the fiber-reinforced composite material (34) such that when the core member (10) is pulled out of the fiber-reinforced composite material (34) along the longitudinal direction (14) towards the front end (18), the sleeve (12) is peeled off from the fiber-reinforced composite material (34) and a cavity (46) is formed in the fiber-reinforced composite material (34).

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