Process for manufacturing rotor blades for a wind turbine

Abstract

A method for manufacturing a rotor blade (200) for a wind turbine (10), the method comprising: Providing a sheet blank (232) comprising sandwiching a plurality of support members (210) between a plurality of filler material segments (238) to form the sheet blank (232); Shaping the blade blank (232) to form a profile of the rotor blade (200), comprising removing portions of the filler material segments (238) and the support elements (210) to form the profile of the rotor blade (200); and Arranging a skin (202) around the outer circumference of the designed sheet blank (232).

Description

[0001] The present subject matter relates generally to wind turbines and more specifically to methods for manufacturing rotor blades for a wind turbine.

[0002] Wind power is considered one of the cleanest, most environmentally friendly energy sources currently available, and wind turbines have received increasing attention in this regard. A modern wind turbine typically comprises a tower, a generator, a gearbox, a nacelle, and one or more rotor blades. The rotor blades capture kinetic energy from the wind using well-known airfoil principles and transfer the kinetic energy through rotational energy to spin a shaft connecting the rotor blades to a gearbox or, if no gearbox is used, directly to a generator. The generator then converts the mechanical energy into electrical energy, which can be fed into a utility grid.

[0003] GB 2 254 381 A and JP 2001 / 165033 A relate to wind turbine blades. DE 31 14 567 A1 relates to a large-area rotor blade. DE 103 37 708 A1 relates to wind turbine rotor blades. WO 2010 / 065 928 A1 relates to wind turbine blades. DE 30 14 347 A1 relates to processes for producing foam-core-supported molded bodies such as wings, rotor blades, etc. with large lengths and widths. DE 44 23 115 A1 relates to propeller blades made of plastic material.

[0004] The manufacturing of rotor blades generally requires the use of specialized tooling and / or molds. For example, the blade halves of a conventional rotor blade are usually formed in large molds that are custom-made for the specific size or shape of the rotor blade being produced. Accordingly, new molds must be sourced or otherwise manufactured for each rotor blade size and shape being produced, which greatly increases the production costs of rotor blades. In addition, conventional methods for manufacturing the blade halves of a rotor blade typically involve the use of an inlay process in which layers of reinforcement material are placed into the custom-made molds by hand. This process is highly labor-intensive and greatly increases the time required to produce a rotor blade.

[0005] Accordingly, there is a need for improved processes for manufacturing wind turbine blades that reduce production costs and increase the speed at which blades can be produced.

[0006] Aspects and advantages of the invention will be described in part in the description which follows, or will be apparent from the description, or may be learned by practice of the invention.

[0007] In one aspect, the present subject matter discloses a method of manufacturing a rotor blade for a wind turbine. The method generally comprises providing a blade blank comprising sandwiching a plurality of support elements between a plurality of filler material segments to form the blade blank. The method comprises shaping the blade blank to form a profile of the rotor blade, comprising removing portions of the filler material segments and the support elements to form the profile of the rotor blade. The method comprises disposing a skin around a periphery of the shaped blade blank.

[0008] Further described herein is a rotor blade for a wind turbine. The rotor blade generally includes a support member extending at least partially between a root and a tip of the rotor blade. The rotor blade also includes a skin defining an outer surface of the rotor blade. Additionally, a filler material may extend between the support member and the skin and may define a profile of the rotor blade.

[0009] These and other features, aspects, and advantages of the present invention will become more fully understood by reference to the following description and the appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0010] A full and practical disclosure of the present invention, including the best mode thereof, directed to one skilled in the art is described in the specification which refers to the accompanying drawings, of which: Fig. 1 is a perspective view of a conventional wind turbine; Fig. Figure 2 is a perspective view of a conventional rotor blade; Fig. 3 illustrates a flow diagram of an embodiment of a method of manufacturing a rotor blade according to aspects of the present subject matter; Fig. 4 illustrates a cross-sectional spanwise view of an embodiment of a rotor blade made in accordance with aspects of the present subject matter; Fig. 5 is a cross-sectional view along the airfoil chord of the rotor blade shown in Fig. 4 is shown; Fig. 6 is a cross-sectional view of a blade blank suitable for use in the manufacture of the rotor blade shown in Fig. 4 is shown; Fig. 7 is a cross-sectional view of the sheet blank shown in Fig. 6 after being formed in accordance with aspects of the present subject matter; Fig. Figure 8 is a cross-sectional view along the span of a rotor blade; Fig. 9 is a cross-sectional view along the airfoil chord of the rotor blade shown in Fig. 8 is shown; Fig. 10 is a cross-sectional view of a blade blank suitable for use in the manufacture of the rotor blade shown in Fig. 8 is shown; and Fig. 11 is a cross-sectional view of the sheet blank shown in Fig. 10 is shown after it has been formed.

[0011] Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is given to illustrate the invention and not to limit the invention. Indeed, those skilled in the art will recognize that various modifications and variations can be made to the present invention without departing from the scope or spirit of the invention. For example, features shown or described as part of one embodiment may be used with another embodiment to provide yet another embodiment. Therefore, the present invention is intended to cover such modifications and variations provided they come within the scope of the appended claims and their equivalents.

[0012] In general, the present subject matter relates to improved methods of manufacturing wind turbine blades, and also to blades manufactured according to such methods. In particular, the disclosed blades may be manufactured by providing a blade blank comprised of a filler material. The blade blank may generally be machined or otherwise shaped to the aerodynamic shape or profile of the blade. A skin may then be applied to an outer periphery of the shaped blade blank to form the outer surface of the blade and to provide a protective coating for the filler material.

[0013] Accordingly, the disclosed methods generally enable the manufacture of rotor blades without the use of specialized tools and molds, and without labor-intensive processes of manually inserting laminate layers into such molds. Therefore, the manufacturing costs and time required to manufacture a rotor blade can be significantly reduced, thereby improving the efficiency of developing new rotor blade designs and the speed with which rotor blades can be brought to market.

[0014] With reference to the drawings, Fig. 1 is a perspective view of a wind turbine 10 of conventional construction. The wind turbine 10 includes a tower 12 with a nacelle 14 attached thereto. A plurality of rotor blades 16 are attached to a rotor hub 18, which in turn is connected to a main flange that rotates a main rotor shaft. The wind turbine power generation and control components are housed within the nacelle 14. It should be noted that the wind turbine 10 of the Fig. 1 is provided for illustrative purposes only to place the present invention in an exemplary field of use. Therefore, one skilled in the art should understand that the invention is not limited to any particular type of wind turbine configuration.

[0015] With reference to Fig. 2 is a perspective view of a rotor blade 16 of conventional construction. As shown, the rotor blade 16 includes a blade root 20 which is used to mount the rotor blade 16 to a mounting flange (not shown) of the rotor hub 18 ( Fig. 1) and a blade tip 22 disposed opposite the blade root 20. The rotor blade 16 may also have a pressure side 24 and a suction side 26 extending between a leading edge 28 and a trailing edge 30. Additionally, the rotor blade 16 may include a span 32 defining the entire length between the blade root 20 and the blade tip 22 and a chord 34 defining the entire length between the leading edge 28 and the trailing edge 30. As will be generally understood, the chord 34 may vary in length relative to the span 32 as the rotor blade 16 extends from the blade root 20 to the blade tip 22.

[0016] Additionally, the rotor blade 16 may define any suitable aerodynamic profile. Therefore, in several embodiments, the rotor blade 16 may define an airfoil-shaped cross-section. For example, the rotor blade 16 may be formed as a symmetrical airfoil or a curved airfoil. Further, the rotor blade 16 may be aeroelastically tailored. Aeroelastically tailoring the rotor blade 16 may involve bending the rotor blade 16 in generally a chord direction and / or in generally a spanwise direction. The chord direction generally corresponds to a direction parallel to the chord 34 defined between the leading and trailing edges 28, 30 of the rotor blade 16. Additionally, the spanwise direction generally corresponds to a direction parallel to the spanwise 32 of the rotor blade 16.The aeroelastic tailoring of the rotor blade 16 may further involve twisting of the rotor blade 16, such as by twisting the rotor blade 16 in generally a chord or span direction.

[0017] As indicated above, the present subject matter generally relates to methods of manufacturing rotor blades for a wind turbine, and also to rotor blades manufactured according to such methods. Accordingly, an embodiment of a method 100 for manufacturing a rotor blade is generally described with reference to Fig. 3 and will be described in more detail with reference to the Fig. 4 - Fig. 11. In addition, an embodiment of a rotor blade 200 manufactured according to the illustrated method 100 is generally described with reference to Fig. 4 - Fig. 7. Furthermore, another rotor blade 300 is described with reference to the Fig. 8 - Fig. 11 described.

[0018] With reference to Fig. 3, in one embodiment, the disclosed method 100 generally includes providing a blade blank formed at least partially from a filler material 102, shaping the blade blank to form a profile of the rotor blade 104, and disposing a skin around an outer periphery of the shaped blade blank 106. As indicated above, such a method 100 can generally provide for a reduction in both production costs and the amount of time required to manufacture a rotor blade. Accordingly, new rotor blade designs can be manufactured with greater efficiency, thereby improving product development and increasing the speed at which rotor blades can be delivered to market. It should be noted that, although the Fig. 3 are shown in a particular order, the steps may generally be performed in any sequence and / or order consistent with the disclosure herein.

[0019] Now with reference to the Fig. 4 and Fig. 5 illustrates an embodiment of a rotor blade 200 made in accordance with aspects of the present subject matter. In particular, Fig. 4 is a cross-sectional view of the rotor blade 200 along a span. Fig. 5 illustrates a cross-sectional view of the rotor blade 200 along a chord.

[0020] As shown, the rotor blade 200 generally includes a skin 202 having an outer surface 204 defining the outer surface of the rotor blade 200 and an inner surface 206 generally defining the outer perimeter of a volume of shaped fill material 208 disposed within the interior of the rotor blade 200. The skin 202 may also be referred to as a "cover skin." The shaped fill material 208 may generally be configured to have a shape or profile that conforms to the aerodynamic shape or profile of the rotor blade 200, such as by forming a blade blank 232 ( Fig. 6) formed from the filler material 208. Therefore, it should be appreciated that the skin 202 may be generally configured to conform to the profile of the shaped filler material 208 such that the outer surface 204 of the skin 202 generally defines the aerodynamic profile of the rotor blade 200. The rotor blade 200 may also include a plurality of support members 210 extending within the rotor blade 200 generally in a spanwise direction, such as from generally adjacent the blade root 212 to generally adjacent the blade tip 214. Additionally, the rotor blade 200 may include a root sleeve 216 disposed at the blade root 212 that extends generally between the shaped filler material 208 and the skin 202.

[0021] Additionally, similar to the rotor blade 16 described above, the rotor blade 200 may include a pressure side 218 and a suction side 220 extending between a leading edge 222 and a trailing edge 224. Further, the rotor blade 200 may include a span 225 defining the entire length between the blade root 212 and the blade tip 214 and a chord 226 defining the entire length between the leading edge 222 and the trailing edge 224. Additionally, as noted above, the rotor blade 200 may generally define an aerodynamic profile. For example, in several embodiments, the fill material 208 and the skin 202 may be configured such that the rotor blade 200 defines an airfoil-shaped cross-section, such as a symmetrical or curved airfoil. The rotor blade 200 may also be configured to include additional aerodynamic features.

[0022] For example, in one embodiment, the rotor blade 200 may be aeroelastically tailored, such as by being bent and / or twisted generally in a chord direction and / or generally in a span direction.

[0023] As stated above, the filler material 208 of the disclosed rotor blade 200 may be generally disposed throughout the interior of the rotor blade 200. In particular, the filler material 208 may be configured to extend between all of the support elements 210 and / or between the support elements 210 and the skin 202 so that it occupies or fills at least a portion of the interior volume of the rotor blade 200. As described herein with reference to Fig. 4 - Fig. 7, the term "internal volume" refers to the volume of the rotor blade 200 defined by the inner surfaces 206 of the skin 202 that is not otherwise occupied by the support member(s) 210 and the root sleeve 216. In several embodiments, the filler material 208 may be configured to occupy a substantial portion of the internal volume of the rotor blade 200. For example, the filler material may be configured to occupy more than 50% of the internal volume of the rotor blade 200, such as more than 75% of the internal volume, more than 85% of the internal volume, or more than 95% of the internal volume.

[0024] It should be noted that the filler material 208 may generally comprise any suitable material capable of being machined or otherwise shaped to the aerodynamic profile of the rotor blade 200. For example, in several embodiments, the filler material 208 may comprise a relatively lightweight, low-density material. Therefore, in a particular embodiment, the filler material 208 may comprise a low-density foam or core material. Suitable low-density foam materials may include, but are not limited to, polystyrene foams (e.g., expanded polystyrene foams), polyurethane foams, other foam rubber / resin-based foams, and various other open-cell or closed-cell foams. Alternatively, the filler material 208 may comprise other suitable low-density materials, such as balsa wood, cork, and the like.

[0025] Still referring to the Fig. 4 and Fig. 5, the support elements 210 may generally be configured as structural components for the disclosed rotor blade 200. For example, the support elements 210 may be configured to provide support for the filler material 208 during manufacture of the rotor blade 200. Additionally, the support elements 210 may be configured to provide stiffness and / or strength (e.g., stiffness and / or strength in the spanwise direction or the flap direction) to the rotor blade 200 during operation of the wind turbine 10. Therefore, it should be appreciated that the support elements 210 may generally have any suitable shape, size, cross-section, and / or configuration that allows the support elements 210 to function as described herein.

[0026] In particular, in several embodiments, the support members 210 may be configured to extend longitudinally within the rotor blade 200 along at least a portion of the span 225 of the rotor blade 200. For example, in the illustrated embodiment, the support members 210 may be configured to extend longitudinally within the rotor blade 200 from adjacent the blade root 212 to adjacent the blade tip 214. Additionally, as shown, the support members 210 may be configured as a solid (i.e., non-hollow) structural member defining a rectangular cross-sectional shape. It should be noted, however, that in alternative embodiments, the support members 210 may generally be configured as solid and / or hollow members defining any suitable cross-sectional shape, such as a circular, elliptical, triangular, or square shape.In further embodiments, the support members 210 may be formed as "I" beams or have any other suitable support beam configuration known in the art. For example, in a particular embodiment of the present subject matter, the support members 210 may have a configuration similar to the spar cap / thrust web configuration used in conventional rotor blades.

[0027] In addition, the support elements 210 may generally define any suitable height 228 and width 230 in the chord direction within the rotor blade 200. For example, in the illustrated embodiment, all of the support elements 210 may define a height 228 that extends generally between the pressure and suction sides 218, 220 of the rotor blade 200, such as by extending between the inner surfaces 206 of the skin 202. Furthermore, in another embodiment, the support elements 210 may be positioned within the rotor blade 200 perpendicular to the orientation shown in Fig. 5 (i.e., in the chord direction). In such an embodiment, the widths 230 may be formed in the chord direction of the support elements 210 to extend between the leading and trailing edges 222, 224 of the rotor blade 200.

[0028] Furthermore, the support members 210 may generally be formed from any suitable material. However, in several embodiments of the present subject matter, the support members 210 may be formed from a relatively stiff and / or durable material to provide rigidity and / or strength to the rotor blade 200. For example, the support members 210 may be formed from any suitable layered composite material (e.g., fiber-reinforced laminates), polymers (e.g., high-strength plastics), metals (e.g., aluminum), wood, or any other suitable material or combination of materials. Additionally, it should be noted that although the disclosed rotor blade 200 is depicted as having four support members 210, the rotor blade 200 may generally include any number of support members 210, such as three or fewer support members 210 or five or more support members 210.

[0029] With reference now to Fig. 6 is a cross-sectional view of one embodiment of a blade blank 232 for use in the manufacture of the rotor blade 200 shown in FIGS. Fig. 4 and Fig. 5. Generally, the blade blank 232 may comprise a volume or block of filler material 208 configured to be machined or otherwise shaped to the aerodynamic profile of the rotor blade 200. Therefore, it should be appreciated that in several embodiments, the blade blank 232 may generally define any suitable shape having dimensions equal to or greater than the span 225, the maximum chord 226, and the maximum height (i.e., the maximum height between the pressure and suction sides 218, 220) of the rotor blade 200 such that portions of the filler material 208 forming the blade blank 232 may be removed to define the profile of the rotor blade 200. For example, in one embodiment, the length 234 of the blade blank 232 may generally be equal to or greater than the span 225 of the rotor blade 200.Similarly, the width 236 of the blade blank 232 may be generally equal to or greater than the maximum chord 226 of the rotor blade 200, and the height (a dimension in the plane of the blade) of the blade blank 232 may be generally equal to or greater than the maximum height (not shown) of the rotor blade 200.

[0030] As in Fig. 6, the blade blank 232 is formed as a layered construction, with the plurality of support members 210 of the rotor blade 200 disposed between a plurality of filler material segments 238, which in particular comprise individual blocks or sections of the filler material 208. In general, the layered construction of the blade blank 232 may be assembled or otherwise formed using any suitable means and / or methods known in the art. Therefore, in several embodiments, the filler material segments 238 and the support members 210 may comprise separate, prefabricated components that may be attached or otherwise assembled to form the blade blank 232. For example, the filler material segments 238 and the support members 210 may be bonded, glued, tethered, fastened, or otherwise attached to one another using any suitable means.Alternatively, the support elements 210 may be formed directly on or within the filler material segments 238. For example, in one embodiment, the support elements 210 may be formed by applying or otherwise assembling multiple layers of a layered composite material directly onto a filler material segment 238. Once the support element 210 is formed onto the filler material segment 238, another filler material segment 238 may then be assembled onto top of the support element 210, repeating the process to form the entire sheet blank 232.

[0031] It should be noted that the width of each filler segment 238 and the space between the support elements 210 generally may vary between different blade blanks 232 depending on numerous factors, such as, but not limited to, the size (e.g., the width 230 in the chord direction) and the number of support elements 210 to be included in the rotor blade 200. Additionally, it should be noted that in one embodiment, the support elements 210 may be evenly spaced from one another within the blade blank 232. Alternatively, the space between all of the support elements 210 may be varied. For example, each filler segment 238 may define a different width such that the space between the support elements 210 varies within the blade blank 232 and, therefore, within the rotor blade 200.

[0032] It should also be noted that in alternative embodiments, the sheet blank 232 need not be formed as a layered construction with multiple separate filler material segments 238. For example, in one embodiment, the sheet blank 232 may include a single continuous volume of filler material 208. In such an embodiment, the sheet blank 232 may be configured such that the support elements 210 can be inserted or otherwise arranged within the sheet blank 232 as needed.

[0033] With reference now to Fig. Figure 7 is a cross-sectional view in the spanwise direction of one embodiment of the blade blank 232 shown in Fig. 6, after being shaped into the aerodynamic profile of the rotor blade 200. Portions of the filler material 208 forming the blade blank 232 are removed to define the profile of the rotor blade 200, particularly as noted above. For example, in several embodiments, the blade blank 232 may be machined or otherwise shaped to form the aerodynamic contours and profile of the pressure side 218, the suction side 220, the leading edge 222, and the trailing edge 224 of the rotor blade 200.

[0034] In general, the sheet blank 232 may be shaped to the desired profile using any suitable shaping means / methods known in the art. For example, in one embodiment, the sheet blank 232 may be machined using any suitable machining process and / or machining equipment, such as a computer numerical control (CNC) machine or any other precision machining equipment. Alternatively, the sheet blank 232 may be shaped using other suitable tools and / or equipment, such as a variety of hand-operated and power hand tools. For example, the sheet blank 232 may be shaped using cutting tools (e.g., knives, saws, and the like), grinding / sandblasting equipment (e.g.,electric grinders, electric sandblasters, sandpaper and the like) and / or any other suitable tools / equipment known in the art.

[0035] It should also be noted that in an alternative embodiment of the present subject matter, one or more filler material segments 238 may be pre-machined or pre-formed to the profile of the rotor blade 200 before being assembled into the blade blank 232. For example, in the illustrated embodiment, each filler material segment 238 may be pre-machined to define a portion of the aerodynamic profile of the rotor blade 200 such that once the blade blank 232 is formed (e.g., by assembling the filler material segments 238 and the support members 210), a complete aerodynamic shape or profile is formed without the need to perform any additional machining and / or shaping processes.

[0036] With further reference to Fig. 7, as indicated above, the disclosed rotor blade 200 may also include a root sleeve 216 disposed at the blade root 212 of the rotor blade 200. In particular, the root sleeve 216 may be disposed between the skin 202 and a root end 240 of the formed blade blank 232. The root sleeve 216 may generally serve as an attachment mechanism for attaching the rotor blade 200 to the rotor hub 18 ( Fig. 1) of a wind turbine 10. Therefore, it should be appreciated that the root sleeve 216 may generally be configured to have any suitable size, shape, and / or configuration that allows the root sleeve 216 to be attached to a rotor hub 18. For example, in one embodiment, the root sleeve 216 may define a substantially cylindrical or circular shape having a diameter or height 242 that generally corresponds to the diameter or height of the mounting flange (not shown) of the rotor hub 18. Additionally, the root sleeve 216 may include a plurality of annularly spaced holes 244 defining a bolt hole pattern that generally corresponds to a bolt hole pattern defined in the rotor hub 18.In another embodiment, a plurality of threaded rods (not shown) may be disposed within the annularly spaced holes 244 to permit attachment of the rotor blade 200 to the rotor hub 18. Of course, it should be appreciated that the root sleeve 216 may be configured to be attached to the rotor hub 18 using any suitable means known in the art.

[0037] Additionally, the root sleeve 216 may generally be formed from any suitable material. However, in several embodiments, the root sleeve 216 may be formed from a relatively stiff and / or durable material. For example, the root sleeve may be formed from any suitable layered composite material (e.g., fiber-reinforced laminates), polymers (e.g., high-strength plastics), metals (e.g., aluminum), wood, or any other suitable material or combination of materials capable of withstanding the loading typically encountered along the attachment site of the rotor hub 18 and the rotor blade 200 during operation of a wind turbine 10. Additionally, in one embodiment, the root sleeve 216 may comprise a prefabricated component configured to be assembled onto the root end 240 of the molded blade blank 232.Alternatively, the root sleeve 216 may be formed directly onto the root end 240 of the formed sheet blank 232. For example, in a particular embodiment of the present subject matter, the root sleeve 216 may be formed by applying or otherwise assembling multiple layers of a layered composite material directly onto the root end 240.

[0038] It should be noted that the root end 240 of the blade blank 232 may generally be machined or otherwise formed to receive the root sleeve 216. For example, in one embodiment, an additional amount of filler material 208 corresponding to the width 246 of the root sleeve 216 may be removed from the blade blank 232 at the root end 240 to allow the root sleeve 216 to be subsequently disposed, assembled, or formed onto the root end 240. Additionally, in a particular embodiment, the width 246 of the root sleeve 216 may generally taper as the root sleeve 216 extends away from the blade root 212. Therefore, as shown in Fig. 7, the root end 240 of the blade blank 232 may generally be machined or otherwise shaped to have a corresponding tapered profile to accommodate the tapered width 246 of the root sleeve 216.

[0039] It should also be noted that in several embodiments of the present subject matter, the entire aerodynamic profile of the rotor blade 200 need not be machined or otherwise formed into the blade blank 232. For example, in one embodiment, only the root end 240 of the blade blank 232 may be initially machined or otherwise formed. In such an embodiment, the root sleeve 216 may be disposed, assembled, or formed on the root end 240 before the remainder of the rotor blade profile is formed into the blade blank 232.

[0040] With reference back to the Fig. 4 and Fig. 5, as indicated above, the rotor blade 200 may also include a skin 202 defining the outer surface of the rotor blade 200. In general, the skin 202 may be configured to conform to and be disposed about an outer periphery of the shaped blade blank 232 and the root sleeve 216 such that a smooth, aerodynamic profile is defined by the rotor blade 200. Additionally, the skin 202, as an outer coating for the shaped blade blank 232, may provide both support and protection for the filler material 208 (i.e., impact protection).

[0041] It should be noted that the skin 202 may generally comprise any suitable material and may be formed using any suitable method and / or process. For example, in one embodiment, the skin 202 may comprise a layered composite material (e.g., a fiber-reinforced laminate) formed around the outer perimeter of the shaped blade blank 232 and the root sleeve 216 using a hand-laid process or any other suitable layering method. In another embodiment, the skin 202 may include a sprayed-on surface coating, such as a sprayed-on polyurethane-elastomer blend. In another embodiment, the skin 202 may comprise a thermoplastic-based coating formed using a heat shrink wrapping process and / or a heat shrink tubing process.

[0042] It should also be noted that in several embodiments, the skin 202 may be disposed on the outer periphery of the formed blade blank 232 one side at a time. For example, in a particular embodiment of the present subject matter, only the profile of the pressure or suction side 218, 220 of the rotor blade 200 may be initially machined or shaped into the blade blank 232. In such an embodiment, the skin 202 may then be applied to the formed pressure or suction side 218, 220 before the remainder of the rotor blade profile is machined or shaped.

[0043] With reference now to the Fig. 8 and Fig. 9 shows another rotor blade 300. In particular, Fig. 8 is a cross-sectional view in the spanwise direction of the rotor blade 300. Fig. 9 illustrates a cross-sectional view in the chord direction of the rotor blade 300.

[0044] In general, the illustrated rotor blade 300 may be similar to the rotor blade 200 described above with reference to Fig. 4 and Fig. 5, an outer cover 302 (e.g., a layered composite material) having an outer surface 304 defining the outer surface of the rotor blade 300 and an inner surface 306 generally conforming to the profile of a volume of the shaped filler material 308 disposed within the interior of the rotor blade 300. The filler material 308 (e.g., a low-density foam material) may generally define a profile corresponding to the aerodynamic profile of the rotor blade 300 and may be configured to occupy at least a portion of the interior volume of the rotor blade 300. As described herein with reference to Fig. 8 - Fig. 11, the term "internal volume" refers to the volume of the rotor blade 300 defined by the inner surfaces 306 of the cover skin 302 that is not otherwise occupied by the support members 310 and the end cap 350. For example, in one embodiment, the filler material 308 may be configured to occupy more than 50% of the internal volume of the rotor blade 300, such as by occupying more than 75% of the internal volume, or more than 85% of the internal volume, or more than 95% of the internal volume. The rotor blade 300 may also have a pressure side 318 and a suction side 320 extending between a leading edge 322 and a trailing edge 324. Additionally, the rotor blade 300 may have a span 325 defining the entire length between a blade root 312 and a blade tip 314, and a chord 326 defining the entire length between the leading edge 322 and the trailing edge 324.Furthermore, as noted above, the filler material 308 and the cover skin 302 of the rotor blade 300 may be configured to define an airfoil-shaped cross-section. Furthermore, the rotor blade 300 may include additional aerodynamic features (e.g., by being aeroelastically tailored).

[0045] However, unlike the root sleeve 216 of the rotor blade 200 described above, the illustrated rotor blade 300 may generally include an end plate 350 disposed at the blade root 312 of the rotor blade 300. In general, the end plate 350 may serve as an attachment mechanism for attaching the rotor blade 300 to the rotor hub 18 ( Fig. 1) of a wind turbine 10. Therefore, it should be appreciated that the end plate 350 may generally be configured to have any suitable size, shape, and / or configuration that allows the end plate 350 to be attached to the rotor hub 18. For example, in one embodiment, the end plate 350 may define a substantially cylindrical or circular shape having a diameter or height 352 that generally corresponds to the diameter or height of a mounting flange (not shown) of the rotor hub 18. Additionally, the end plate 350 may include a plurality of threaded rods 354 annularly disposed around a hub side 356 of the end plate 350 for attaching the rotor blade 300 to the rotor hub 18.In other embodiments, the end plate 350 may include a plurality of annularly spaced holes (not shown) defining a bolt hole pattern that generally corresponds to a bolt hole pattern defined by the rotor hub 18. Alternatively, it should be appreciated that the end plate 350 may be configured to be attached to the rotor hub 18 using any suitable means known in the art.

[0046] The end plate 350 of the disclosed rotor blade 300 may generally be formed from any suitable material. However, in several embodiments, the end plate 350 may be formed from a relatively stiff and / or durable material. For example, the end plate 350 may be formed from any suitable layered composite material (e.g., fiber-reinforced laminates), polymers (e.g., high-strength plastics), metals (e.g., aluminum), wood, or any other suitable material or combination of materials capable of withstanding the loading typically encountered along the attachment site of the rotor hub 18 and the rotor blade 300 during operation of a wind turbine 10.

[0047] With further reference to the Fig. 8 and Fig. 9, the rotor blade 300 may also include a support member 310 extending outwardly from the end plate 350 in a generally spanwise direction. For example, the support member 310 may be attached to the end plate 350 such that the support member 310 extends outwardly from a blade side 358 of the end plate 350 in the blade tip direction. It should be appreciated that the support member 310 may generally be configured to be attached to the end plate 350 using any suitable means. For example, in the illustrated embodiment, the end plate 350 may define an opening 360 into which the support member 310 is inserted and / or secured.In such an embodiment, it should be noted that the support member 310 may be secured within the opening 360 using any suitable attachment mechanism, such as screws, bolts, retaining clips, retaining brackets, adhesives, tapes, and the like, and / or using any suitable attachment method, such as welding, press-fitting, bonding, and the like. In another embodiment, the support member 310 may be configured to be attached to the blade side 358 of the end plate 350 and may extend outwardly therefrom, such as using any of the attachment mechanisms and / or methods described above.

[0048] In general, the support elements 310 may be configured similarly to the support elements 210 described with reference to the Fig. 4 and Fig. 5. Therefore, the support members 310 may be configured as a structural component for the disclosed rotor blade 300, such as by being configured to provide support for the filler material 308 during manufacture of the rotor blade 300 and / or to provide stiffness and / or strength to the rotor blade 300 during operation of the wind turbine 10. Therefore, it should be appreciated that the support member 310 may generally have any suitable shape, size, cross-section, and / or configuration that allows the support member 310 to function as described herein.

[0049] For example, the support member 310 may generally be configured to extend longitudinally within the rotor blade 300 along at least a portion of the span 325 of the rotor blade 300. Therefore, in the illustrated embodiment, the support member 310 may be configured to extend longitudinally within the rotor blade 300 from adjacent the blade root 312 to adjacent the blade tip 314. Additionally, as shown, the support member 310 may be configured as a rod- or beam-like structural member. For example, in the illustrated embodiment, the support member 310 may be configured as a hollow rod or beam having a circular or tubular cross-sectional shape.However, it should be noted that in alternative embodiments, the support member 310 may be formed as a solid and / or hollow member defining any suitable cross-sectional shape, such as an elliptical, triangular, rectangular, or square shape. In further embodiments, the support member 310 may be formed as an "I" beam or may have any other suitable support beam configuration known in the art. For example, in one particular embodiment, the support member 310 may have a configuration similar to the spar / thrust web configuration used in conventional rotor blades.

[0050] Furthermore, the support element 310 may generally have any suitable height 328 and width 330 in the chord direction. For example, as particularly shown in Fig. 9, the support member 310 may have a height 328 and a width 330 that extend only partially between the pressure and suction sides 318, 320 and the leading and trailing edges 322, 324 of the rotor blade 300, respectively. However, in an alternative embodiment, the height 328 may extend substantially between the pressure and suction sides 318, 320 of the rotor blade 300, such as by extending between the inner surfaces of the cover skin 302. Similarly, in another embodiment, the support member 310 may have a width 330 in the chord direction that extends substantially between the leading and trailing edges 322, 324 of the rotor blade 300.

[0051] It should be noted that although the illustrated rotor blade 300 includes only a single support member 310, the rotor blade 300 may generally include any number of support members 310 extending outwardly from the end plate 350, such as two, three, or more support members 310.

[0052] Now with reference to Fig. 10 is a cross-sectional view of the embodiment of the support member 310 shown in the Fig. 8 and Fig. 9, with a sheet blank 332 disposed thereon. In general, the sheet blank 332 may be configured similarly to the sheet blank 232 described above with reference to Fig. 6. Therefore, the blade blank 332 may generally include a volume of filler material 308 configured to be machined or shaped into the aerodynamic profile of the rotor blade 300. Therefore, the blade blank 332 may generally define any suitable shape having dimensions equal to or greater than the wingspan 325, the maximum chord 326, and the maximum height (not shown) of the rotor blade 300 such that portions of the filler material 308 forming the blade blank 332 may be removed to define the profile of the rotor blade. For example, the length 334 of the blade blank 332 may generally be equal to or greater than the wingspan 325 of the rotor blade 300.Similarly, the width 336 of the blade blank 332 may be generally equal to or greater than the maximum chord 326 of the rotor blade 300, and the height (now shown) of the blade blank 332 may be generally equal to or greater than the maximum height of the rotor blade 300. Additionally, as described below, in one embodiment, the support member 310 may have an initial length that is greater than the length 334 of the blade blank 332. Therefore, as shown, an exposed end 362 of the support member 310 may extend generally outwardly from the blade blank 332 when the blade blank 332 is disposed within the support member 310.

[0053] In contrast to the layered construction described above with reference to Fig. 6 is the sheet molding 332, which is described in Fig. 10, generally configured to be disposed on and around the support member 310. For example, the sheet blank 332 may define an opening (not shown) that generally conforms to the cross-sectional shape of the support member 310 such that the sheet blank 332 may be disposed on the support member 310. Additionally, the sheet blank 332 may be configured to be attached to the support member 310 and / or to the end plate 350. For example, in one embodiment, the sheet blank 332 may be bonded to the outer periphery of the support member 310 and the sheet side 358 of the end plate 350 using any suitable adhesive. Further, it should be noted that in several embodiments, the sheet blank 332 may comprise a single, uniform mass of the filler material 308. Alternatively, as shown in Fig. 10, the sheet blank 332 may include a plurality of filler material segments 364 disposed along the length of the support member 310. In such an embodiment, the filler material segments 364 may be configured to be attached to one another in addition to being attached to the support member 310 and / or the end plate 350. For example, the filler material segments 364 may be bonded, glued, tethered, attached, or otherwise attached to one another using any suitable means.

[0054] With reference now to Fig. Figure 11 is a cross-sectional view in the spanwise direction of one embodiment of the blade blank 332 shown in Fig. 10, after being shaped into the aerodynamic profile of the rotor blade 300. In particular, once the blade blank 332 is disposed on and around the support member 310, portions of the filler material 308 forming the blade blank 332 may be removed to define the profile of the rotor blade 300. For example, similar to the embodiment described above, the blade blank 332 may be machined or otherwise shaped to form the aerodynamic contours and profile of the pressure side 318, the suction side 320, the leading edge 322, and the trailing edge 324 of the rotor blade 300. Therefore, in one embodiment, the blade blank 332 may be shaped using any suitable machining process and machining equipment.Alternatively, the sheet blank 332 may be formed using any other suitable tool and / or equipment known in the art.

[0055] As stated above, in one embodiment of the present subject matter, the support member 310 may have an initial length that is greater than the length 334 of the sheet blank 332. In such an embodiment, it should be appreciated that this extended length may assist in machining or otherwise shaping the sheet blank 332. For example, when machining the sheet blank 332 using a CNC machine or any other suitable machining equipment, the sheet blank 332 may be secured within the machine at one end by the end plate 350 and at the other end by the exposed end 362 ( Fig. 10) of the support element 310. Accordingly, to complete the formation of the aerodynamic profile of the rotor blade 300, the exposed end 362 of the support element 310 may be removed during or after the machining or design process. Therefore, as shown in Fig. 10, the end 362 of the support member 310 may generally be removed, such as by machining or cutting, to form the blade tip 314 of the rotor blade 300.

[0056] It should be noted that in an alternative embodiment of the present subject matter, one or more filler material segments 364 may be pre-machined or pre-formed to the aerodynamic profile of the rotor blade 300 before being assembled into the blade blank 332. For example, in the illustrated embodiment, each of the filler material segments 364 may be pre-formed to define a portion of the profile of the rotor blade 300 such that once the blade blank 332 is formed (e.g., by assembling the filler material segments onto the support member 310), a complete aerodynamic profile is formed.

[0057] One skilled in the art will readily recognize that numerous different combinations of the rotor blade components described herein may be used within the scope of the present subject matter. For example, the support member 310 described with reference to Fig. 8 - Fig. 11, also in the rotor blade 200 described with reference to the Fig. 4 - Fig. 7, in addition to the plurality of support members 210, and vice versa. Similarly, the end plate 350 and the root sleeve 216 may be used interchangeably or in combination to allow the disclosed rotor blades 200, 300 to be attached to the rotor hub 18 of a wind turbine.

[0058] It should also be noted that, in several embodiments, the disclosed methods may be particularly advantageous for quickly and efficiently manufacturing prototype rotor blades for testing new airfoil designs and the like. In particular, the disclosed methods provide for manufacturing rotor blades without the need for special, custom-machined molds. Therefore, new airfoil designs and / or blade configurations / features (e.g., aeroelastically tailored blades, winglets, and the like) may be manufactured and promptly tested without the time required to create and / or source such special molds. However, the disclosed methods may also be used to manufacture rotor blades for use in the field. For example, rotor blades manufactured according to the disclosed methods may be used as the main and / or auxiliary rotor blades of a wind turbine.

[0059] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any device or system and performing any enclosed method. The patentable scope is defined by the appended claims and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the exact language of the claims, or if they include equivalent structural elements with insubstantial differences from the exact language of the claims.

[0060] A method of manufacturing a rotor blade 200 for a wind turbine 10 and a rotor blade 200 manufactured according to such a method are disclosed. The method generally comprises providing a blade blank 232 comprising sandwiching a plurality of support elements between a plurality of filler material segments to form the blade blank. The method comprises shaping the blade blank 232 to form a profile of the rotor blade 200, comprising removing portions of the filler material segments and the support elements to form the profile of the rotor blade. The method comprises disposing a skin 202 around the outer periphery of the shaped blade blank 232. List of reference symbols 300 rotor blades 302 Cover skin 304 Outer surface (of the cover skin) 306 Inner surface (of the cover skin) 308 Filling material 310 support element 312 root 314 lace 318 printed page 320 suction side 322 front edge 324 rear edge 326 profile chord 328 height 330 width 332 leaf mold 334 Length of the leaf blank 336 Width of the sheet blank 350 end plate 352 height 354 threaded rod 356 hub side 358 page 360 opening in end plate 362 Exposed end 364 filling material segments

Claims

[1] A method for manufacturing a rotor blade (200) for a wind turbine (10), the method comprising: Providing a sheet blank (232) comprising sandwiching a plurality of support members (210) between a plurality of filler material segments (238) to form the sheet blank (232); Shaping the blade blank (232) to form a profile of the rotor blade (200), comprising removing portions of the filler material segments (238) and the support elements (210) to form the profile of the rotor blade (200); and Arranging a skin (202) around the outer circumference of the designed sheet blank (232). [2] The method of claim 1, wherein the filler material segments (238) comprise a low density material. [3] The method of claim 2, wherein the low density material comprises a foam material. [4] The method of claim 1, wherein the plurality of support members (210) are formed from a layered composite material. [5] The method of claim 1, wherein each of the plurality of support members (210) extends between inner surfaces (206) of the skin (202). [6] The method of claim 1, further comprising forming a root sleeve (216) directly on a root end (240) of the leaf blank (232). [7] The method of claim 6, wherein the root sleeve (216) is formed from a layered composite material. [8] The method of claim 6, further comprising forming the root sleeve (216) for attachment to a hub (18) of the wind turbine (10). [9] The method of claim 1, wherein the portions of the filler material segments (238) and the support members (210) are removed using a machining process. [10] The method of claim 1, wherein an outer surface (204) of the skin (202) defines an outer surface of the rotor blade (200). [11] The method of claim 1, wherein the skin (202) comprises a layered composite material. [12] The method of claim 1, further comprising shaping a root end (240) of the sheet blank (232) such that the root end (240) has a tapered profile. [13] The method of claim 12, further comprising disposing a root sleeve (216) on the root end (240), wherein a tapered width of the root sleeve (216) corresponds to the tapered profile of the root end (240). [14] The method of claim 1, wherein the support elements (210) are evenly spaced from one another within the sheet blank (232). [15] The method of claim 1, wherein the support elements (210) extend longitudinally within the rotor blade (200) from adjacent the blade root (212) to adjacent the blade tip (214). [16] The method of claim 1, wherein the sheet blank (232) has a substantially full cross-section.

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