JP2018168789A - Windmill blade - Google Patents

Abstract

To provide a windmill blade capable of improving rigidity of a blade part even in a case where a foamed resin is used for a core material of the blade part.SOLUTION: The present invention relates to a windmill blade 1 comprising: an attachment part 11 which is attached to a rotary body of a windmill; and a blade part 12 extending from the attachment part 11. The windmill blade 1 comprises: a core material 13 including at least a blade core part 13A which is formed in accordance with a shape of the blade part 12 and consists of a foam molding of resin beads; and an outer cover 15 which is formed to cover a surface of the core material 13 and consists of a fiber reinforced resin. In the core material 13, a density of the foamed resin in a portion along an edge of the blade part 12 is higher than a density of the foamed resin inside the core material 13.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a windmill blade attached to a rotating body of a windmill, and more particularly to a windmill blade provided with a core material made of foamed resin and an outer skin made of fiber-reinforced resin.

  Conventionally, wind turbines for wind power generation have a structure in which a plurality of wind turbine blades are attached to a rotating body. Each windmill blade has a streamlined blade cross-sectional structure, and the windmill rotates when wind hits the windmill blade. In order to efficiently rotate the windmill by wind power, it is desirable to reduce the weight of the blade for the windmill.

  In view of such a point, for example, Patent Document 1 includes an outer shell made of fiber-reinforced resin as an outer skin of a windmill blade, and an acrylic resin foam inside the outer skin forming a blade portion of the windmill blade. Wind turbine blades filled with a core material made of

  According to this windmill blade, the core material inside the outer skin forming the blade portion is made of an acrylic resin foam while maintaining the strength of the windmill blade by making the outer skin made of fiber reinforced resin. Thus, the weight of the windmill blade can be reduced.

Japanese Patent No. 6002865

  However, as shown in Patent Document 1, even if an acrylic resin foam is filled inside the outer skin forming the blade portion, the rigidity of the blade portion of the wind turbine blade cannot be sufficiently maintained. This is because the core material made of an acrylic resin foam is made by cutting a bulk material for the purpose of weight reduction, and the density of the acrylic foam is uniform.

  And when the windmill rotates, if the rigidity of the blade portion of the windmill blade attached to the rotating body is not sufficient, the windmill cannot be efficiently rotated by the wind force. For example, the power generation efficiency by the windmill may be reduced. is assumed.

  The present invention has been made in view of these points, and the object of the present invention is to increase the rigidity of the blade portion even when a foamed resin is used as the core material of the blade portion. It is to provide a blade for a windmill.

  As a result of intensive studies, the inventors have arranged a reinforcing frame on the periphery of the blade if the mechanical strength of the portion along the periphery of the blade portion of the wind turbine blade is made higher than the strength of the other portions. It was thought that the blades were reinforced as if they were, and the rigidity was increased. Therefore, the inventors focused on the density of the core material made of foamed resin disposed inside the blade portion as a technique for increasing the strength of the peripheral edge of the blade portion.

  The present invention is based on such inventors' attention, and a blade for a wind turbine according to the present invention includes an attachment portion that is attached to a rotating body of the wind turbine, and a blade portion that extends from the attachment portion. The windmill blade is formed so as to cover a core material made of a foamed resin bead formed at least according to the shape of the blade portion and the surface of the core material. An outer skin made of fiber reinforced resin, and the density of the foamed resin in the portion along the peripheral edge of the blade portion of the core material is higher than the density of the foamed resin inside the core material. It is characterized by.

  According to the present invention, the blade portion of the windmill blade is constituted by the core material made of resin foam and the outer skin made of fiber reinforced resin covering the entire surface of the core material. The weight can be reduced.

  In addition to this, since the density of the foamed resin in the core material along the periphery of the blade part is higher than the density of the foamed resin inside the core material, the machine along the periphery of the blade part. Strength can be increased. Thereby, since a blade | wing part is reinforced as if the reinforcement frame is arrange | positioned at the periphery of a blade | wing part, the rigidity as the whole blade | wing part can be improved.

  Here, the “periphery of the blade portion” as used in the present invention refers to the state of the blade portion when the blade portion is viewed from the direction along the rotation axis of the rotating body with the windmill blade attached to the rotating body of the windmill. It is the periphery.

  By the way, in this invention, since the density of the foamed resin of the part along the periphery of a blade | wing part was raised as mentioned above among core materials, the core material of the core material was carried out to the front end side of the blade | wing part along the periphery of a blade | wing part. The density of the foamed resin is also increased. As a result, although the rigidity of the blade portion is increased, the mass on the tip side of the blade portion is increased.

  Therefore, as a more preferable aspect, the density of the reinforcing fiber in the outer skin on the tip surface of the blade part is lower than the density of the reinforcing fiber in the outer part of the other part of the blade part. According to this aspect, the density of the reinforcing fiber in the outer skin at the tip surface of the blade part is made lower than the density of the reinforcing fiber in the outer skin of the other part of the blade part. can do. As a result, the wind turbine blade can be prevented from swinging with the wind turbine blade attached to the rotating body, and the wind turbine can be rotated more stably.

  As a more preferable aspect, the core material is a foamed resin bead in which a portion formed according to the shape of the mounting portion and a portion formed according to the shape of the blade portion are integrally formed. It consists of a molded body.

  According to this aspect, since the portion formed according to the shape of the attachment portion and the portion formed according to the shape of the blade portion of the core material are integrally formed, the blade for the windmill The overall rigidity can be increased. In addition, the boundary portion between the wind turbine blade mounting portion and the blade portion has a narrowed shape due to its shape, and it is easy to concentrate stress on this portion, but this portion is also integrally molded, The strength of the windmill blade can be increased.

  As a more preferable aspect, the attachment portion is formed with a through-hole through which a fastener for fixing the windmill blade to the rotating body is inserted at a position where the core member is sandwiched between the outer skins. Yes.

  According to this aspect, the fastener can be inserted into the through hole, the fastener can be fastened so as to sandwich the windmill blade and the rotating body, and the windmill blade can be fixed to the rotating body. Due to the fastening force of the fastener, the core material of the attachment portion of the wind turbine blade is compressed, and a reaction force due to the restoring force of the compressed core material acts on the fastener. This reaction force can reduce the looseness of the fastener.

  According to the present invention, even if a foamed resin is used for the core material of the blade portion, the rigidity of the blade portion can be increased.

It is a typical perspective view of the blade for windmills concerning this embodiment of the present invention. (A) is a front view of the blade for windmills shown in FIG. 1, (b) is the side view. (A) is an AA arrow directional cross-sectional view shown to Fig.2 (a), (b) is a BB arrow directional cross-sectional view shown to Fig.2 (a). It is CC sectional view taken on the line in FIG.2 (b). It is the typical perspective view which showed the state before bonding the prepregs corresponded to an outer skin to a core material, and press-molding the windmill blade. It is a principal part expanded sectional view of the state which attached the blade for windmills concerning this embodiment to the rotating plate.

Hereinafter, an example of a blade for a windmill according to an embodiment of the present invention will be described.
FIG. 1 is a schematic perspective view of a windmill blade 1 according to this embodiment of the present invention. Fig.2 (a) is a front view of the blade 1 for windmills shown in FIG. 1, (b) is the side view. 3A is a cross-sectional view taken along the line AA shown in FIG. 2A, and FIG. 3B is a cross-sectional view taken along the line BB shown in FIG. FIG. 4 is a cross-sectional view taken along line C-C shown in FIG.

1. Overall Structure of Windmill Blade As shown in FIG. 1, a windmill blade 1 according to this embodiment is for a windmill that is attached to a plurality of rotating plates (rotators) 21, 21 that rotate as a rotating shaft of the windmill. It is a blade. The windmill blade 1 includes an attachment portion 11 that is attached to the rotating plates 21 and 21 of the windmill, and a blade portion 12 that extends from the attachment portion 11. The blade portion 12 has a streamlined cross-sectional shape that is pointed on one side in the width direction, and is twisted while maintaining this cross-sectional shape from the distal end to the proximal end of the blade portion 12 (see, for example, FIG. 3B). ).

  Further, as shown in FIGS. 2A and 2B, the blade portion 12 increases in thickness from the center in the longitudinal direction toward the base end, and proceeds toward the attachment portion 11 in the vicinity of the attachment portion 11. The blade portion 12 is formed so that the width and thickness thereof are reduced. The attachment portion 11 is formed with three through holes 19, 19, 19 for attaching to the rotating plates 21, 21 of the windmill.

  As shown in FIGS. 3A, 3B and 4, the attachment portion 11 and the blade portion 12 are a core member 13, an outer skin 15 that contacts the core member 13 and covers the entire surface of the core member 13, It has. That is, the windmill blade 1 has a structure in which an outer skin 15 is filled with a core material 13 made of a resin foam.

2. About Core Material 13 The core material 13 includes a blade core portion 13 </ b> A formed according to the shape of the blade portion 12 and an attachment core portion 13 </ b> B formed according to the shape of the attachment portion 11. The blade core portion 13A and the attachment core portion 13B are made of a foamed molded body of resin beads formed integrally.

  In this embodiment, since the blade core portion 13A and the attachment core portion 13B are integrally formed, the rigidity of the entire wind turbine blade 1 can be increased. In addition, the boundary portion between the attachment portion 11 and the blade portion 12 has a narrowed shape due to its shape, and stress is likely to be concentrated on this portion, but the blade core portion 13A and the attachment core portion 13B including this portion are Since it is integrally formed, the strength of the wind turbine blade 1 can be increased.

  Here, the resin bead foam molded body to be the core material 13 is manufactured by an in-mold foam molding method. Specifically, pre-expanded resin beads containing a foaming agent are filled in a mold, and the resin beads are further foamed by heating with a heat medium such as hot water or steam, and the resin beads are expanded by the foaming pressure of the resin beads. By fusing and integrating, a foam molded body of resin beads can be produced.

  Examples of resin foam resins (resin beads) include polyester resins, acrylic resins, polycarbonate resins, polymethacrylamide resins, polyolefin resins, and other thermoplastic resins, phenol resins, and epoxy resins. And those containing as a main component a reaction curable resin such as a vinyl ester resin and an unsaturated polyester resin. In addition, styrene-methyl methacrylate-maleic anhydride copolymer resin (SMM), polyphenylene oxide resin, and the like may be used. The resin contained in the resin foam need not be one kind alone, and may be two or more kinds.

  For example, examples of the polyester resin include polyethylene terephthalate resin, polypropylene terephthalate resin, polybutylene terephthalate resin, polycyclohexanedimethylene terephthalate resin, polyethylene naphthalate resin, and polybutylene naphthalate resin.

  Here, as shown in FIG. 2, FIG. 3 (b), and FIG. 4, the density of the foamed resin in the portion 13a along the peripheral edge 12a of the blade portion 12 of the blade core portion 13A of the core member 13 is It is higher than the density of the foamed resin in the inside 13b of the core portion 13A.

For example, the density of the foamed resin in the inner part 13b of the blade core part 13A is preferably in the range of 0.09 to 0.45 g / cm ³ , and further, the density of the foamed resin in the inner part 13b of the blade core part 13A is The ratio of the density of the foamed resin in the portion 13a along the peripheral edge 12a of the blade portion 12 of the blade core portion 13A is preferably in the range of 1.05 to 2.00, more preferably 1.05 to 1. It is in the range of 70. The density of the foamed resin is a value measured according to JIS K7222: 2005 “Measurement of foamed plastic and rubber-apparent density”.

  By setting the foamed resin in the inner part 13b of the blade core part 13A within the above-described density range, the weight of the windmill blade 1 can be reduced. Furthermore, by setting the ratio of the density of the foamed resin in the portion 13a along the peripheral edge 12a of the blade portion 12 of the blade core portion 13A to the density of the foamed resin in the inside 13b of the blade core portion 13A, the blade portion The mechanical strength along the 12 peripheral edges 12a can be increased.

  Thereby, since the blade | wing part 12 is reinforced as if the reinforcement frame is arrange | positioned at the peripheral edge 12a of the blade | wing part 12, the rigidity as the whole blade | wing part 12 can be improved. As a result, when the wind turbine rotates, the rigidity of the blade portion 12 of the wind turbine blade 1 attached to the rotating plates 21 and 21 can be ensured. For this reason, a windmill can be efficiently rotated with wind power, for example, the power generation efficiency by a windmill can be improved.

  The peripheral edge 12a of the blade portion 12 is the peripheral edge when the blade portion 12 is viewed from the direction along the rotation axis of the rotating plate 21 with the windmill blade 1 attached to the rotating plates 21 and 21 of the windmill. That is, in the front view of the windmill blade shown in FIG. 2A, the peripheral edge when the blade portion 12 of the windmill blade 1 is viewed.

3. About the outer skin 15 The outer skin 15 covers the entire surface of the core material 13 composed of the blade core portion 13A and the attachment core portion 13B. In addition, the through-hole 19 mentioned above is formed in the position where the attachment core part 13B of the core material 13 was pinched | interposed into the outer skin | cover 15, so that these may be penetrated.

  The outer skin 15 is made of a fiber reinforced resin in which a reinforced fiber is impregnated with a synthetic resin. As the reinforcing fiber constituting the fiber reinforced resin, inorganic fibers such as glass fiber, carbon fiber, silicon carbide fiber, alumina fiber, Tyranno fiber, basalt fiber, ceramic fiber; metal fiber such as stainless steel fiber and steel fiber; aramid fiber, Examples thereof include organic fibers such as polyethylene fibers and polyparaphenylene benzoxador (PBO) fibers; or boron fibers. Reinforcing fibers may be used alone or in combination of two or more. Among these, carbon fiber, glass fiber, or aramid fiber is preferable, and carbon fiber is more preferable. These reinforcing fibers have excellent mechanical strength despite being lightweight.

  The reinforcing fiber may be either a long fiber or a short fiber, but is preferably used as a reinforcing fiber substrate processed into a desired shape. As the reinforcing fiber base material, a woven fabric base material, a knitted base material, a nonwoven fabric, or a face material obtained by binding (sewing) a fiber bundle (strand) in which reinforcing fibers are aligned in one direction with a thread. Etc. In the present embodiment, the reinforcing fiber base is a woven base in which long fibers are woven, and examples of the weaving of the woven base include plain weave, twill, satin weave and the like. The fiber reinforced base material may be used without laminating only one fiber reinforced base material, or a plurality of fiber reinforced base materials may be laminated and used as a laminated fiber reinforced base material.

  A synthetic resin is a resin that is impregnated into reinforcing fibers and bonds the reinforcing fibers together. The reinforcing fibers can be bonded and integrated by the impregnated synthetic resin. The synthetic resin impregnated into the reinforcing fibers may be either a thermosetting resin or a thermoplastic resin, but more preferably a thermosetting resin.

  The thermosetting resin is not particularly limited. For example, epoxy resin, unsaturated polyester resin, phenol resin, melamine resin, polyurethane resin, silicon resin, maleimide resin, vinyl ester resin, cyanide. Examples thereof include acid ester resins, or resins obtained by prepolymerizing maleimide resins and cyanate ester resins. A thermosetting resin may be used independently or 2 or more types may be used together. Of these, epoxy resins or vinyl ester resins are preferable. According to these synthetic resins, a fiber reinforced resin having excellent elasticity can be formed, and the impact resistance of the resulting wind turbine blade 1 can be improved. Further, the thermosetting resin may contain additives such as a curing agent and a curing accelerator. The fiber reinforced resin may be molded by a sheet molding compound (SMC).

  The content of the thermosetting resin in the fiber reinforced resin is preferably 20 to 80% by weight, and more preferably 30 to 70% by weight. When there is too little content of a thermosetting resin, there exists a possibility that the binding property of reinforcement fibers may become inadequate. Moreover, when there is too much content of a thermosetting resin, there exists a possibility that the mechanical strength of the outer skin | casing 15 may fall and the impact resistance of the blade 1 for windmills cannot fully be improved.

In the present embodiment, the density of the reinforcing fibers of the outer skin 15 on the tip surface 12 c of the blade part 12 is lower than the density of the reinforcing fibers of the outer skin 15 of the other part of the blade part 12. Specifically, when the reinforcing fiber is a carbon fiber, the density of the reinforcing fiber of the outer skin 15 on the tip surface 12c of the blade portion 12 is preferably in the range of 1.4 to 1.9 g / m ² . The density of the outer skin 15 of the other part (other part) of the blade part 12 is 1.5 to 2.0 g / on the premise that the density of the reinforcing fiber of the outer skin 15 on the tip surface 12c of the blade part 12 is low. it is preferably in the range of m ^2.

  Thus, since the density of the reinforcing fiber of the outer skin 15 on the tip surface 12c of the blade portion 12 is lower than the density of the reinforcing fiber of the outer skin 15 of the other portion of the blade portion 12, the mass of the tip side of the blade portion 12 is reduced. The increase can be reduced. Thereby, the windmill blade 1 can suppress the vibration of the windmill attached to the rotating plate 21, and the windmill can be rotated more stably.

4). Method for Manufacturing Windmill Blade 1 A method for manufacturing the windmill blade 1 will be described below. FIG. 5 is a schematic perspective view showing a state before the prepregs 15A and 15A corresponding to the outer skin are bonded to the core member 13 and the windmill blade 1 is press-molded.

  First, a resin-bead foam-molded body that becomes the core member 13 of the wind turbine blade 1 is manufactured by an in-mold foam-molding method. Specifically, a pre-foamed resin bead containing a foaming agent is filled in a mold (not shown) according to the shape of the core material 13, and the resin bead is heated with a heat medium such as hot water or steam. Further, the resin beads are fused and integrated by the foaming pressure of the resin beads.

  Thereby, the core material 13 in which the blade core portion 13A and the attachment core portion 13B are integrally formed can be obtained. Due to the shape of the blade core portion 13A of the core material 13 obtained, the density of the foamed resin in the portion 13a along the peripheral edge 12a of the blade portion 12 among the foamed resin constituting the blade core portion 13A is the blade core. It becomes higher than the density of the foamed resin in the inside 13b of the portion 13A (see, for example, FIG. 2A).

  Next, as shown in FIG. 5, a lower mold 41 and an upper mold 42 in which a cavity C corresponding to the shape of the windmill blade 1 is formed are prepared, and a prepreg 15 </ b> A corresponding to the outer skin is arranged on the lower mold 41. The core material 13 is disposed thereon, and the top is covered with the prepreg 15A. As the prepreg 15A, for example, a woven base material made of the above-described reinforcing fiber is used which is impregnated with an uncured thermosetting resin (synthetic resin). The synthetic resin may be a thermoplastic resin.

  In this state, while the lower mold 41 and the upper mold 42 are heated, the upper mold 42 is moved to the lower mold 41 and these are clamped. When the synthetic resin is a thermosetting resin, its curing temperature The windmill blade 1 is press-molded while being heated as described above (and, if the synthetic resin is a thermoplastic resin, at or above its softening point). At this time, the portion of the prepreg 15A that is molded as the tip surface 12c of the blade portion 12 flows more greatly during mold clamping than the portion of the other prepreg 15A. Thereby, the density of the reinforcing fibers of the outer skin 15 on the tip surface 12 c of the blade part 12 becomes lower than the density of the reinforcing fibers of the outer skin 15 of the other part of the blade part 12.

  Furthermore, as for the ratio of the thickness of the blade core portion 13A to the thickness of the prepreg 15A in the mold clamping direction, the portion along the peripheral edge 12a of the blade portion 12 is the largest. For this reason, the foamed resin of the part 13a along the peripheral edge 12a of the blade core part 13A is pressurized with a larger load at the time of mold clamping than the resin of other parts. As a result, among the foamed resins constituting the blade core portion 13A, the density of the foamed resin in the portion 13a along the peripheral edge 12a of the blade portion 12 is higher than the density of the foamed resin on the inner surface surrounded by the portion 13a. can do.

5. Attachment Structure of Windmill Blade 1 FIG. 6 is an enlarged cross-sectional view of a main part in a state where the windmill blade 1 according to the present embodiment is attached to the rotating plates 21 and 22. As shown in FIG. 1, the windmill blade 1 is attached to the pair of rotating plates 21 and 21 so as to be sandwiched between the pair of rotating plates 21 and 21.

  Specifically, as shown in FIGS. 1 and 6, the windmill blade 1 is attached to the rotating plates 21 and 21 by using three through holes 19 formed in the attachment portion 11 of the windmill blade 1. First, a cylindrical guide material 51 for guiding a bolt 61 described later and a ring-shaped guide material 52 are disposed in the through hole 19.

  Next, the rotating plates 21 and 21 are sandwiched between both sides of the attachment portion 11 of the windmill blade 1. In this state, the bolt 61 constituting a part of the fastener is inserted into the through hole 19 from one side of the through hole 19. Next, a nut 62 constituting a part of the fastener is screwed onto the bolt 61 from the other side of the through hole 19 and is tightened.

  As a result, the bolt 61 is inserted into the through hole 19, the nut 62 is fastened to the bolt 61 so that the windmill blade 1 and the rotating plates 21 and 21 are sandwiched, and the windmill blade 1 is fixed to the rotating plates 21 and 21. can do. At this time, the attachment core portion 13 </ b> B of the attachment portion 11 of the wind turbine blade 1 is compressed by the fastening force of the bolt 61 and the nut 62. Then, a reaction force caused by the restoring force of the compressed mounting core portion 13 </ b> B acts on the bolt 61 and the nut 62. This reaction force can reduce loosening between the bolt 61 and the nut 62.

  As mentioned above, although it explained in full detail using embodiment of this invention, a concrete structure is not limited to this embodiment and an Example, There exists a design change in the range which does not deviate from the summary of this invention. They are also included in the present invention.

  For example, in the present embodiment, the core material is formed by integrally forming both the attachment core portion and the blade core portion, and at least if the density relationship of the foamed resin in the blade core portion satisfies the above-described range, These may be in a separated state.

1: windmill blade, 11: attachment portion, 12: blade portion, 13: core material, 13A: blade core portion, 13B: attachment core portion, 19: through hole, 12: blade portion, 15: outer skin, 19: penetration Hole

Claims (4)

A blade for a windmill comprising an attachment portion attached to a rotating body of the windmill, and a blade portion extending from the attachment portion;
The windmill blade is formed according to the shape of at least the blade portion, and a core material made of a foam molded body of resin beads,
An outer skin made of a fiber reinforced resin formed so as to cover the surface of the core material,
The windmill blade according to claim 1, wherein a density of the foamed resin in a portion along the peripheral edge of the blade portion of the core material is higher than a density of the foamed resin inside the core material.   The windmill blade according to claim 1, wherein the density of the reinforcing fiber in the outer skin at the tip surface of the blade portion is lower than the density of the reinforcing fiber in the outer skin at the other portion of the blade portion.   The core material is formed of a resin bead foam molded body in which a portion formed according to the shape of the mounting portion and a portion formed according to the shape of the blade portion are integrally formed. The blade for windmills according to claim 1 or 2, characterized by the above-mentioned.   The attachment portion is formed with a through-hole through which a fastener for fixing the windmill blade to the rotating body is inserted at a position where the core member is sandwiched between the outer skins. The blade for wind turbines according to claim 3.

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