Rotary wing

Abstract

The present invention addresses the problem of providing a rotary wing that is excellent in light weight, rigidity, fatigue characteristics, and dimensional accuracy, and in particular, has excellent fatigue characteristics, that is, durability, the rotary wing including a following component [A] that constitutes at least a skin, which is the surface layer of the rotary wing, and a following component [B] that constitutes a core, which is the of the skin, the component [B] being the rotary wing enclosed in the component [A] at least in a cross section at the center of the distance between the central axis during rotation and the tip of the rotary wing.　The component [A] is a continuous fiber base material containing continuous reinforcing fibers and a matrix resin, the component [B] is a porous body containing reinforcing fibers and resin, the reinforcing fibers have a mass-average fiber length of 1-15 mm, and voids are formed by bonding the reinforcing fibers through the resin.

Description

rotor blades

[0001] The present invention relates to a rotor blade suitable for use in rotorcraft, propeller-driven fixed-wing aircraft, wind turbines, and the like, and more particularly to a rotor blade having a skin made of a continuous fiber base material and a specific core.

[0002] For air transportation such as aircraft, weight reduction is an important issue because it directly affects the flight distance. In addition, in order to reduce the weight of the aircraft, the rotors (also called blades) used as the driving force for flight require not only light weight but also high dimensional accuracy to precisely mold the complex shapes of the wing. Furthermore, durability is also important because the rotors rotate at high speeds.

[0003] Patent Document 1 exemplifies a rotor having a core portion containing a foam and a skin made of carbon fiber impregnated with a thermosetting resin. The rotor is proposed to suppress mass variation by using a melamine resin foam as the core and a substrate made of biaxial or more carbon fiber woven fabric impregnated with a thermosetting resin as the skin.

[0004] Patent Document 2 exemplifies a method for manufacturing a composite wing by stacking reinforced fiber substrates (so-called prepregs) in which reinforcing fibers are impregnated with resin, placing a foaming agent in the resulting internal space, and heating and expanding the foaming agent. By controlling the curing temperature and foaming temperature, the method proposes a composite wing with high dimensional accuracy and quality.

[0005] JP 2022-9927 A JP 2019-1024 A

[0006] As mentioned above, rotor blades have complex shapes and require both light weight and high dimensional accuracy. However, with rotor blades that use resin foam as the core material, even though they can ensure light weight, dimensional accuracy can be lost during molding, and as a result of insufficient rigidity, fatigue properties can be poor and the usable life of the rotor blade can be shorter than expected.

[0007] Furthermore, even if dimensional precision of the outer layer can be achieved during molding of a rotor using a foaming agent, it can be difficult to mold with high positional precision when using an internal reinforcing material, making balance adjustment impossible. Furthermore, because the core material of the resulting rotor is a resin foam, it lacks rigidity as a rotor, resulting in poor fatigue properties and a shorter usable life as a rotor than expected.

[0008] Therefore, an object of the present invention is to provide a rotor blade that is lightweight, has high rigidity, and has excellent dimensional accuracy, thereby exhibiting excellent fatigue properties and durability.

[0009] The rotor of the present invention comprises the following component [A] constituting at least the skin, which is the surface layer of the rotor, and the following component [B] constituting the core, which is the interior of the skin, wherein component [B] is contained within component [A] at least in a cross section at the center of the distance from the central axis to the tip of the rotor during rotation. Component [A]: A continuous fiber substrate containing continuous reinforcing fibers and a matrix resin. Component [B]: A porous body containing reinforcing fibers and a resin, wherein the reinforcing fibers have a mass average fiber length of 1 mm or more and 15 mm or less.

[0010] The rotor of the present invention has a core that is a porous body containing reinforcing fibers and resin, and is therefore lightweight, has excellent rigidity, and has excellent dimensional accuracy, making it possible to provide a rotor that has excellent fatigue properties and durability.

[0011] FIG. 1 is a plan view showing an example of a rotor of the present invention. FIG. 2 is a plan view showing an example of a cross section of a rotor of the present invention. FIG. 3 is a plan view showing an example of a cross section of a rotor of the present invention having a reinforcing layer. FIG. 4 is a plan view showing an example of a cross section of a rotor of the present invention having cuts. FIG. 5 is a perspective view from above showing an example of the arrangement of cuts. FIG. 6 is a plan view showing an example of a cross section of a rotor of the present invention, (a) is a cross section of the rotor, and (b) is a cross section of a plane passing through the leading edge and trailing edge of the rotor and approximately perpendicular to the cross section. FIG. 7 is a plan view showing an example of a cross section of a rotor of the present invention having a spar. FIG. 8 is a plan view showing an example of a cross section with an enlarged view of a joint between the spar and the skin. FIG. 9 is a plan view showing an example of a cross section of a rotor of the present invention having a hollow in the core. FIG. 10 is a plan view showing an example of a cross section of a rotor of the present invention having a hollow and a reinforcing layer. FIG. 11 is a plan view showing an example of a cross section of a rotor of the present invention having a hollow and a spar. FIG. 12 is a plan view showing an example of a cross section of a rotor of the present invention having hollows of various shapes. FIG. 13 is a schematic view showing an example of an anchoring portion between the core and the skin in a rotor of the present invention. Fig. 1 is a schematic diagram showing an example of a core part in the present invention. Fig. 2 is a cross-sectional view illustrating a cut portion or a concave-convex portion provided in a core part, (a) being an example of a cut portion, (b) being an example of a concave portion, and (c) being an example of a convex portion. Fig. 3 is a cross-sectional view showing an example of a rotor according to the present invention, in which a concave-convex portion is provided in the component [B]. Fig. 4 is a cross-sectional view showing an example of a rotor according to the present invention, in which a cut portion is provided in the component [B].

[0012] The rotor of the present invention will be described in detail below.

[0013] The rotor of the present invention includes a component [A] (described later) that constitutes at least a skin, which is the surface layer of the rotor, and a component [B] (described later) that constitutes a core, which is the interior of the skin, and is configured so that component [B] is contained within component [A] at least in a cross section at the center of the distance from the central axis to the tip of the rotor during rotation.

[0014] Furthermore, the rotor of the present invention has a structure in which, when viewed in a cross section perpendicular to its rotation axis and a line perpendicular to the rotation axis and passing through the tip of each blade, at least at the midpoint of the line segment connecting the rotation axis and the blade tip, it has a skin portion forming a surface layer and a core portion covered by the skin portion, the skin portion being composed of a continuous fiber base material containing continuous reinforcing fibers and a matrix resin, and the core portion being composed of a porous body containing reinforcing fibers and resin with a mass average fiber length of 1 mm or more and 15 mm or less.

[0015] In a preferred embodiment, the rotor of the present invention has a reinforcing portion on the skin side where the core portion is provided in order to further reinforce or support the skin portion and the core portion, as shown in Figures 3, 7, and 11. The reinforcing portion is preferably made of a continuous fiber substrate containing continuous reinforcing fibers and a matrix resin. The rotor of the present invention may also be provided with a member connecting the skin portions, as shown by 18 in Figure 7. The member is preferably made of a continuous fiber substrate containing continuous reinforcing fibers and a matrix resin. In addition, a hollow portion may be formed in the core portion as shown in Figures 11 and 12, in order to adjust the center of gravity balance of the entire rotor.

[0016] That is, in the rotor of the present invention, "component A" refers to a member that constitutes the skin portion and is made of a continuous fiber base material containing continuous reinforcing fibers and a matrix resin; "component B" refers to a member that constitutes the core portion and is made of a porous body containing reinforcing fibers with a mass average fiber length of 1 mm or more and 15 mm or less and a resin; "component C" refers to a member that constitutes the reinforcing portion and is made of a continuous fiber base material containing continuous reinforcing fibers and a matrix resin; and "component D" refers to a member that penetrates the core portion and connects the skin portions (for convenience, referred to as a "girder portion") and is made of a continuous fiber base material containing continuous reinforcing fibers and a matrix resin. Below, the rotor of the present invention will be described while explaining each of the skin portion, core portion, reinforcing portion, and girder portion.

[0017] Here, Figure 1 is a plan view showing an example of a rotor. A rotor usually consists of two to six blades joined together to form a so-called propeller, and Figure 1 shows a propeller made up of two blades joined together. In this invention, unless otherwise specified, a single blade, i.e., one half of the blade in the plan view shown in Figure 1, is referred to as a rotor. Furthermore, unless otherwise specified, the description will be of a cross section taken at the center of the distance between the central axis (also called the axis of rotation) during rotation and the tip of the rotor, i.e., the midpoint between the central axis and the tip of the rotor.

[0018] The rotor rotates around the central axis shown in 2 in Figure 1, which accelerates the air and generates propulsion. The central axis here refers to the central axis of rotation. The distance from the central axis to the tip of the rotor is shown in 3 in Figure 1, and the tip of the rotor is defined as the farthest point when a straight line is drawn from the central axis to the tip. Unless otherwise specified, the starting point of the central axis is defined as the center of the thickness of the mounting part, which is the base of the rotor.

[0019] Next, Figure 2 shows an example of a cross section taken at the center of the distance between the central axis and the tip of the rotor blade. Note that the cross section here refers to a cross section perpendicular to a straight line connecting the central axis and the tip of the rotor blade.

[0020] Furthermore, the impeller of the present invention includes, in a cross section taken at the center of the distance between the central axis and the tip of the impeller during rotation, a component [A] constituting the skin and a component [B] constituting the core inside the skin, and the component [B] is contained within the component [A]. Here, "contained within" refers to a state in which the component [B] is not exposed on the surface of the impeller, i.e., the entire portion of the impeller corresponding to the outer surface of the impeller in the cross section is composed of the component [A]. Because the component [B] is porous, if it is exposed, it may absorb water, such as rain, during use, and the lightweight properties of the impeller may not be ensured.

[0021] In order to obtain efficient propulsion, a rotor usually has a shape in which the cross-sectional shape changes continuously from the base to the tip of the rotor. Therefore, as described above, at least in a cross-section at the center of the distance between the central axis during rotation and the tip of the rotor, the rotor includes a component [A] that constitutes the skin and a component [B] that constitutes the core inside the skin, and the component [B] is contained within the component [A]. However, the tip of the rotor may not have a core, but the rotor may include a component [A] that constitutes the skin and a component [B] that constitutes the core inside the skin over the entire longitudinal area of ​​the rotor.

[0022] The portion of component [B] included in component [A] preferably occupies a length corresponding to 50% or more, more preferably 70% or more, and even more preferably 80% or more, of the length from the central shaft to the tip of the rotor, which is taken as 100%.

[0023] In the configuration of FIG. 2 in which component [B] is included in component [A], when the length from the central shaft to the tip of the impeller is taken as 100%, by configuring the portion with a length corresponding to 50% or more, it is possible to obtain a lightweight impeller with high dimensional accuracy, which is preferable.

[0024] Furthermore, the rotor is usually attached to a mounting portion of the central shaft called a hub, but since the mounting portion is often joined with a metal bolt or the like, the base of the rotor does not necessarily have to have a skin-core structure, and may be made of a fiber-reinforced composite material that does not have a porous structure, or may be molded integrally with a metal member for joining to the central shaft.

[0025] Furthermore, the rotor of the present invention may have a reinforcing portion on the skin side where the core portion is provided in order to further reinforce or support the skin portion and the core portion, and the reinforcing portion is preferably composed of a continuous fiber substrate containing continuous reinforcing fibers and a matrix resin. When the length from the central shaft to the tip of the rotor is taken as 100%, the reinforcing portion is preferably located in a portion of the length corresponding to 50% or more, and component [B] is preferably anchored along a step portion of different thickness.

[0026] The reinforcing portion is preferably disposed on the rotor because it can improve the rotor's rigidity. Furthermore, in order to improve the rotor's rigidity, the reinforcing portion is preferably disposed over a length corresponding to 50% or more of the rotor's longitudinal length, as shown in FIG. 1 at 5, which is taken as 100%. More preferably, the reinforcing portion is disposed over 60% or more, and even more preferably, 80% or more. Disposing the reinforcing portion over 50% or more of the longitudinal length of the rotor provides high rotor rigidity and durability, which is preferable.

[0027] Furthermore, when the thickness of the skin is Ts, the thickness of the component [C] can be, for example, Ts × 0.1 to 5. It can be selected depending on the balance between lightness and rigidity, but Ts × 0.2 to 3 is more preferable, and Ts × 0.3 to 2 is even more preferable.

[0028] Furthermore, from the viewpoint of improving the rigidity in the longitudinal direction, the reinforcing fibers contained in the component [C] are preferably continuous reinforcing fibers, and more preferably, the continuous reinforcing fibers are laminated in the 0° direction, with the longitudinal direction being taken as 0°.

[0029] As shown in 10 in Fig. 3, when the component [C] is placed, a step is formed at the portion where the component [C] is bonded to the component [A], but it is preferable that the step formed by bonding the component [C] to the component [A] has a continuously changing thickness. Furthermore, it is preferable that the component [B] is anchored along the step portion.

[0030] As will be described later, component [B] contains reinforcing fibers, making it a lightweight, highly rigid porous body. This allows it to support component [C] with high precision during molding, making it possible to manufacture a rotor with extremely high dimensional precision. Furthermore, by anchoring to component [B], including the stepped portion, the reinforcing layer is firmly supported during continuous use, thereby achieving dramatically improved fatigue properties. Note that, as will be described later, anchoring here refers to a state in which the reinforcing fibers of component [B] penetrate component [A] by 5 μm or more.

[0031] Furthermore, in the rotor of the present invention, component [B] preferably has cuts or irregularities with a depth of 0.1 mm or more in a portion of a length corresponding to 50% or more of the length from the central axis of the rotor to the tip of the rotor, except for portions corresponding to 5 mm from the leading edge and 5 mm from the trailing edge, and component [A] preferably penetrates into the cuts or irregularities, more preferably 70% or more, and even more preferably 80% or more.

[0032] Figure 4 shows an example of a rotor blade in which a cut is provided in the component [B], and it is more preferable that the depth of the cut shown in 12 in Figure 4 is 0.5 mm or more and 2 mm or less. Alternatively, the height or depth of the concave and convex portions is preferably 0.05 mm or more. If the depth of the cut exceeds 2 mm, or the depth of the concave portions or the height of the convex portions exceeds 2 mm, the bending modulus of elasticity of the porous body may decrease. Furthermore, since it is preferable that the component [A] penetrates into the cut portions or the concave-convex portions, it is preferable that the depth of the cut portions is 0.5 mm or more and the depth of the concave-convex portions is 0.05 mm or more. "By having the cut portions or the concave-convex portions and the component [A] penetrating into the cut portions or the concave-convex portions, the adhesion between the component [B] and the component [A] is further ensured, and the durability when the rotor is used can be dramatically improved. If the depth of the cut portions is 0.5 mm or the depth of the concave-convex portions is 0.05 mm or less, the adhesion of the component [A] decreases, and if the depth of the cut portions is 2 mm or more or the depth of the concave-convex portions is 0.5 mm or more, the penetration amount of the component [A] is insufficient, resulting in the formation of a resin-rich region or voids, which may result in a decrease in mechanical properties.

[0033] Here, in terms of the adhesion between the component [A] and the component [B], a more preferable example of the incision in the present invention is a structure in which the width gradually narrows from the surface toward the depth direction, as shown in FIG. 15( a). However, in terms of the fluidity of the component [A] or the durability of the component [B], the component [A] is more likely to penetrate into the uneven portion as shown in FIG. 15( b) or 15( c), making it less likely to form a resin-rich portion or a stress-concentrated portion. The incision or uneven portion can be selectively formed in consideration of the fluidity and rigidity of the component [A] and the component [B]. Furthermore, the incision or uneven portion may be arranged linearly along the longitudinal direction, or may be arranged in a curved shape along the shape of either the leading edge or the trailing edge. However, a curved shape along the shape is preferred because it ensures better adhesion.

[0034] Figure 5 shows an example of a cutout arranged in the longitudinal direction. The cutout does not necessarily have to be arranged linearly, so when the length from the central axis of the impeller to the tip of the impeller is taken as 100%, the actual length of the cutout may exceed 100%. Furthermore, there may be one cutout or multiple cutouts. From the viewpoint of adhesiveness, it is preferable to have multiple cutouts. However, since too many cutouts will lead to a decrease in the bending modulus of the porous body, it is desirable that the total volume of the cutouts be 5% or less of the total volume of the impeller.

[0035] On the other hand, when an uneven portion is provided, as shown in Figure 15(b) and Figure 15(c), the component [A] penetrates into the recesses or between the protrusions of the component [B], and anchoring occurs, thereby further ensuring adhesion between the component [B] and the component [A], and the durability of the impeller when used can be dramatically improved.

[0036] Although there are no particular limitations on the shape of the unevenness, it is preferable that the unevenness be a continuously curved surface like a dimple. If there are sharp changes in curvature or rectangular corners, the resin becomes rich and stress is concentrated, which leads to a deterioration in fatigue properties.

[0037] Next, component [B] is porous, and the average porosity of the porous portion is preferably in the range of 10% to 97% by volume. Furthermore, when the blade is divided into three parts at a plane perpendicular to the line connecting the leading edge and the trailing edge at a point midway from the blade tip to the root, and the parts are divided into three parts with equal volumes, it is preferable that the maximum average porosity differs from the minimum average porosity by 3% by volume or more.

[0038] Here, the straight line connecting the leading edge and the trailing edge is shown at 16 in Figure 6(a), the cross section perpendicular to said line is the plane shown by reference numeral 17 in Figure 6(a), and the division into three is performed on a plane parallel to said cross section (see reference numeral 34 in Figure 6(b)).

[0039] In particular, in the porous portion of the three-divided component [B], when a sample is taken in a range of 10 mm in width (i.e., 10 mm in thickness) along the cross section shown in 16 in Figure 6, it is preferable that the average porosity of the porous portion in the central three-divided portion (the portion sandwiched between the faces indicated by reference numeral 34 in Figure 6(b)) differs by 3 volume % or more from that in the other three-divided portions.

[0040] The high average porosity of the central portion, which is divided into three parts, contributes to weight reduction while maintaining rigidity, and is preferable because it makes it easier to balance the rotor when it is rotating, which makes it easier to improve durability.

[0041] Furthermore, when the porosity is observed in the thickness direction in at least the central portion of the three divided portions, it is preferable that the porosity on the side in contact with the component [A] is low and the porosity observed in the central portion is high. The difference therebetween is preferably 4 volume % or more. A low porosity in the portion close to the component [A] is preferable because it can further enhance the anchoring ability of the component [A] and the component [B].

[0042] Furthermore, in the rotor of the present invention, it is preferable that the component [D] forms a continuous portion connecting the component [A], that is, the rotor of the present invention has a spar portion made of a continuous fiber base material containing continuous reinforcing fibers and a matrix resin.

[0043] The component [D] may be connected directly to the component [A] or may be connected via another member, for example, the component [C]. An example of a spar is shown in 18 in Figure 7, and by connecting the skins continuously, the rigidity of the rotor blade can be dramatically increased.

[0044] The thickness of the spar (the thickness of the sheet if the continuous fiber substrate is sheet-shaped, or the thickness of the rod if the continuous fiber substrate is rod-shaped) is, when the skin thickness is Ts, for example, Ts × 0.1 to 5. It can be selected based on the balance between lightness and rigidity, but Ts × 0.2 to 3 is more preferable, and Ts × 0.3 to 2 is even more preferable.

[0045] Furthermore, from the viewpoint of improving rigidity in the longitudinal direction, the reinforcing layer is preferably made of continuous fibers, and it is more preferable that the fibers are laminated in the 0° direction, with the longitudinal direction being taken as 0°.

[0046] Furthermore, as shown in an example at 20 in Figure 8, the area where component [D] and component [A] are connected is preferably reinforced with a reinforcing material, with the amount of reinforcing material gradually decreasing with increasing distance from component [D]. This is preferable because the amount of reinforcing material gradually decreasing with increasing distance from component [D] allows the load to be efficiently transmitted to the spar. Furthermore, when a surface where the angle between component [D] and component [A] at the point where component [D] and component [A] are connected is cut out, the curvature R of the curved surface formed by the reinforcing material preferably has a radius of 1 to 100 mm. If the radius of curvature R is 1 mm or more, the load can be efficiently transmitted to the spar. If the radius of curvature R is 100 mm or less, the mass of the rotor may be large. More preferably, it is 1.5 to 50 mm, and even more preferably 2 to 20 mm.

[0047] Furthermore, it is preferable that the component [B] is also anchored to the component [D]. As will be described later, the component [B] contains reinforcing fibers, and is therefore a porous body that is lightweight and highly rigid. This makes it possible to support the spar with high precision during molding, and thus makes it possible to manufacture a rotor with extremely high dimensional precision.

[0048] Furthermore, since the component [D] and the joint between the component [A] and the component [D] are both anchored to the component [B], the spar can be firmly supported during continuous use, thereby achieving dramatically high fatigue properties.

[0049] In addition, the rotor of the present invention preferably has a hollow portion having an average equivalent sphere diameter of more than 1 mm.

[0050] FIG. 9 shows an example of a rotor having a hollow portion, which is preferable because it not only achieves weight reduction but also allows for adjustment of the mass balance.

[0051] As described above, the component [B] is a porous body, and therefore, it is possible to increase rigidity while maintaining a light weight, and it is possible to control with high precision the position at which the hollow portion is to be disposed during molding, and it is possible to manufacture a rotor with extremely high mass precision.

[0052] Furthermore, as shown in 22 of Figure 9, it is preferable that a continuous fiber substrate containing continuous reinforcing fibers and a matrix resin is arranged on the surface forming the hollow portion (such continuous fiber substrate arranged on the surface forming the hollow portion is referred to as "element element [E]"). In other words, the hollow portion is preferably defined by a continuous fiber substrate containing continuous reinforcing fibers and a matrix resin.

[0053] By disposing the component [E], not only can the rigidity of the rotor be further improved, but also when water infiltrates the rotor, absorption of water into the porous portion of the component [B] can be prevented, and thus the durability of the rotor is dramatically improved, which is preferable.

[0054] Furthermore, when the thickness of the skin is Ts, the thickness of the continuous fiber base material constituting the component [E] can be, for example, Ts × 0.1 to 5. It can be selected based on the balance between lightness and rigidity, but Ts × 0.2 to 3 is more preferable, and Ts × 0.3 to 2 is even more preferable.

[0055] Furthermore, in terms of improving the rigidity in the longitudinal direction, it is more preferable that the continuous fibers of the continuous fiber base material constituting component [E] are stacked in the 0° direction, with the longitudinal direction being 0°.

[0056] Figure 10 shows an example of a rotor having a hollow portion and component [C], and Figure 11 shows an example of a rotor having a hollow portion and component [D]. Figure 12 shows examples of cross sections of rotors having hollow portions of various shapes, but the hollow portions may be circular or polygonal, and the corners of polygonal shapes may be chamfered.

[0057] Each component will be described in detail below.

[0058] The component [A] is a member constituting the skin portion and is made of a continuous fiber substrate containing continuous reinforcing fibers and a matrix resin. There are no particular limitations on the type of reinforcing fiber that can be used, and examples include metal fibers such as aluminum fibers, brass fibers, and stainless steel fibers; carbon fibers (including graphite fibers) such as polyacrylonitrile (PAN)-based carbon fibers, rayon-based carbon fibers, lignin-based carbon fibers, and pitch-based carbon fibers; insulating fibers such as glass fibers; organic fibers such as aramid fibers, polyparaphenylenebenzoxazole (PBO) fibers, polyphenylene sulfide fibers, polyester fibers, acrylic fibers, nylon fibers, and polyethylene fibers; and inorganic fibers such as silicon carbide fibers and silicon nitride fibers.

[0059] These fibers may also be surface-treated, such as by coating with a metal that is a conductor, treatment with a coupling agent, treatment with a sizing agent, treatment with a binder, or treatment with an additive.

[0060] Furthermore, these reinforcing fibers may be used alone or in combination of two or more types.

[0061] Among these, from the viewpoint of weight reduction, carbon fibers such as PAN-based carbon fibers, pitch-based carbon fibers, and rayon-based carbon fibers, which have excellent specific strength and specific rigidity, are preferably used. Furthermore, from the viewpoint of improving the economic efficiency of the resulting molded article, glass fibers are preferably used, and in particular, a combination of carbon fibers and glass fibers is preferred from the viewpoint of a balance between mechanical properties and economic efficiency. Furthermore, from the viewpoint of improving the impact absorption and formability of the resulting molded article, aramid fibers are preferably used, and in particular, a combination of carbon fibers and aramid fibers is preferred from the viewpoint of a balance between mechanical properties and impact absorption. Furthermore, from the viewpoint of improving the conductivity of the resulting molded article, reinforcing fibers coated with metals such as nickel, copper, and ytterbium can also be used.

[0062] Among these, in the present invention, discontinuous carbon fibers are more preferably used as the discontinuous reinforcing fibers in the core material, and PAN-based carbon fibers, which are excellent in mechanical properties such as strength and elastic modulus, are particularly preferably used as the carbon fibers. Furthermore, from the viewpoints of rigidity and durability, continuous carbon fibers are particularly preferred.

[0063] The continuous carbon fibers may be unidirectional or biaxially or more woven. From the viewpoint of durability, the outermost layer is preferably a woven fabric.

[0064] Furthermore, from the viewpoint of the rigidity of the rotor, the tensile modulus of the continuous reinforcing fibers is preferably more than 200 GPa, more preferably in the range of 220 GPa to 400 GPa. If the tensile modulus of the reinforcing fibers is less than 200 GPa, the rigidity of the rotor may be poor, and if it is more than 400 GPa, the crystallinity of the reinforcing fibers needs to be increased, which makes it difficult to manufacture such reinforcing fibers.

[0065] It is preferable that the tensile modulus of the reinforcing fiber is within the above range in terms of further improving the rigidity of the rotor blade and improving the manufacturability of the reinforcing fiber. The tensile modulus of the reinforcing fiber can be measured by the strand tensile test described in JIS R7601-1986.

[0066] In the present invention, the matrix resin used in component [A] can preferably be a thermosetting resin such as an unsaturated polyester resin, a vinyl ester resin, an epoxy resin, a phenolic (resol type) resin, a urea resin, a melamine resin, a polyimide resin, a maleimide resin, or a benzoxazine resin. A resin obtained by blending two or more of these resins may also be used. Among these, an epoxy resin is particularly preferred from the viewpoint of the mechanical properties and heat resistance of the molded article. To achieve excellent mechanical properties, an epoxy resin is preferably included as the main component of the resin used, and specifically, is preferably included in an amount of 60% by mass or more relative to the total mass of the resin composition.

[0067] As the epoxy resin, epoxy resins whose precursors are amines, phenols, or compounds having a carbon-carbon double bond are preferably used.

[0068] Any compound having an active group capable of reacting with an epoxy group can be used as a curing agent for epoxy resins. Compounds having an amino group, an acid anhydride group, or an azide group are suitable. Specific examples of curing agents include dicyandiamide, diaminodiphenylmethane (including various isomers), diaminodiphenylsulfone (including various isomers), aminobenzoic acid esters, various acid anhydrides, phenol novolac resins, cresol novolac resins, polyphenol compounds, imidazole derivatives, aliphatic amines, tetramethylguanidine, thiourea adduct amines, carboxylic acid anhydrides (e.g., methylhexahydrophthalic anhydride), carboxylic acid hydrazides, carboxylic acid amides, polymercaptans, and Lewis acid complexes (e.g., boron trifluoride ethylamine complexes). These curing agents may be used alone or in combination.

[0069] By using an aromatic diamine as a curing agent, a cured resin with good heat resistance can be obtained. In particular, various isomers of diaminodiphenyl sulfone are most suitable for obtaining a cured resin with good heat resistance. When using an aromatic diamine as a curing agent, it is preferable to add it in an amount that is stoichiometrically equivalent. In some cases, for example, an equivalent ratio of 0.7 to 0.8 can be used to obtain a cured resin with a high elastic modulus.

[0070] Furthermore, by using a combination of dicyandiamide and a urea compound (for example, 3,4-dichlorophenyl-1,1-dimethylurea) or an imidazole as a curing agent, high heat and water resistance can be obtained while curing at a relatively low temperature. Curing with an acid anhydride gives a cured resin with a lower water absorption rate than when an amine compound is used as a curing agent. In addition, latent versions of these curing agents, for example, microencapsulated versions, can be used.

[0071] Among the curing agents for epoxy resins, a combination of dicyandiamide and a urea compound is preferably used because it tends to enable curing at a temperature of 145° C. or higher within 10 minutes.

[0072] Alternatively, these epoxy resins and curing agents, or a pre-reaction product of a part of them, can be blended into the composition, which may be effective in adjusting viscosity and improving storage stability.

[0073] It is also preferable to add a dissolved thermoplastic resin to the epoxy resin composition. Such a thermoplastic resin is generally preferably a thermoplastic resin having a bond selected from carbon-carbon bonds, amide bonds, imide bonds, ester bonds, ether bonds, carbonate bonds, urethane bonds, thioether bonds, sulfone bonds, and carbonyl bonds in the main chain, but it may also have a partially crosslinked structure. It may also be crystalline or amorphous. It is particularly preferable to dissolve at least one resin selected from the group consisting of polyamide, polycarbonate, polyacetal, polyphenylene oxide, polyphenylene sulfide, polyarylate, polyester, polyamideimide, polyimide (e.g., polyimide having a phenyltrimethylindane structure), polyetherimide, polysulfone, polyethersulfone, polyetherketone, polyetheretherketone, polyaramid, polyethernitrile, and polybenzimidazole in the epoxy resin composition.

[0074] As the matrix resin used in component [A], an epoxy resin is preferably used from the viewpoint of durability. The glass transition point obtained after curing can be, for example, 120°C or higher. More preferably, it is 150°C or higher, and even more preferably, it is 200°C or higher. Since the rotor blades are used outdoors, insufficient heat resistance can lead to poor durability, and therefore, a temperature of 120°C or higher is preferred. The glass transition temperature can be measured by dynamic viscoelasticity measurement at a temperature rise rate of 5°C / min.

[0075] Furthermore, a thermoplastic resin is also preferably used as the matrix resin used in the component [A], and the thermoplastic resin may be either crystalline or amorphous.

[0076] Examples of crystalline thermoplastic resins include polyester, polyolefin, polyoxymethylene (POM), polyamide (PA), polyarylene sulfide, polyketone (PK), polyether ketone (PEK), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyether nitrile (PEN), fluorine-based resins, and liquid crystal polymers (LCPs). Examples of polyesters include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), and liquid crystal polyesters. Examples of polyolefins include polyethylene (PE), polypropylene (PP), and polybutylene. Examples of polyarylene sulfides include polyphenylene sulfide (PPS). Examples of fluorine-based resins include polytetrafluoroethylene.

[0077] Examples of amorphous thermoplastic resins include polystyrene, polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), polyphenylene ether (PPE), polyimide (PI), polyamideimide (PAI), polyetherimide (PEI), polysulfone (PSU), polyethersulfone, and polyarylate (PAR). Other examples of thermoplastic resins used in the core material include phenoxy resins, and thermoplastic elastomers such as polystyrenes, polyolefins, polyurethanes, polyesters, polyamides, polybutadiene, polyisoprene, fluororesins, and acrylonitriles, as well as copolymers and modified products. Among these, preferred thermoplastic resins used in the core material include polyolefins, polyamides, polyesters, polycarbonates, polystyrenes, modified polyphenylene ethers, and polyarylene sulfides.

[0078] Of these amorphous thermoplastic resins, polyolefins are preferred from the viewpoint of the light weight of the resulting molded article, polyamides are preferred from the viewpoint of strength, polyesters are preferred from the viewpoint of moisture absorption, and amorphous resins such as polycarbonates, polystyrenes, and modified polyphenylene ethers are preferred from the viewpoint of surface appearance, polyarylene sulfides are preferred from the viewpoint of heat resistance, and polyether ether ketones are preferably used from the viewpoint of continuous use temperature.

[0079] Furthermore, preferable examples of the constituent elements [C], [D], and [E] are continuous fiber substrates containing the same reinforcing fibers and matrix resin as those used in the aforementioned constituent element [A].

[0080] Furthermore, the continuous fiber base material containing continuous reinforcing fibers and a matrix resin that constitutes the components [C], [D], and [E] may be the same as or different from that that constitutes the component [A]. By selecting and using the optimal matrix resin, reinforcing fibers, and form of the reinforcing fibers according to the physical properties and characteristics required for the components [C], [D], and [E], it is possible to achieve economical weight reduction.

[0081] The component [B] is a member that constitutes the core portion and is a porous body that contains reinforcing fibers having a mass average fiber length of 1 mm or more and 15 mm or less and a resin.

[0082] Fig. 13 is a schematic diagram of the interface of the anchoring portion where the constituent element [A] and the constituent element [B] are anchored. As shown in Fig. 13, the constituent element [B] is a porous body composed of reinforcing fibers 26, a resin 27, and voids 25.

[0083] In the rotor of the present invention, it is preferable that some of the reinforcing fibers contained in component [B] penetrate beyond the interface with component [A].

[0084] The state in which the reinforcing fibers contained in component [B] penetrate beyond the interface with component [A] is exemplified by the embodiment shown in Fig. 13. That is, as shown in Fig. 13, at the interface formed between the matrix resin constituting component [A] and the resin constituting component [B], reinforcing fibers derived from component [B] are present throughout both the matrix resin of component [A] and the resin of component [B]. In other words, it can be said that the matrix resin of component [A] and the resin of component [B] are firmly bonded together due to anchoring by the reinforcing fibers derived from component [B].

[0085] The degree of penetration of the reinforcing fibers derived from the component [B] is not limited as long as the effects of the present invention are not impaired. However, from the viewpoint that the core part functions as a bonding medium and affects the bondability between the skin part and the core part, it is preferable that the length (penetration length) of the reinforcing fibers derived from the component [B] beyond the interface with the component [A] is preferably 5 μm or more, more preferably 10 μm or more.

[0086] The penetration length of the reinforcing fiber originating from the component [B] into the component [A] is indicated by the distance between a plane that is parallel to the macro boundary surface 33 between the component [A] and the component [B] and is in contact with the tip of the fiber that has penetrated into the skin, and a plane that is parallel to the macro boundary surface and is in contact with the base of the fiber that has penetrated into the skin, that is, the point at which the fiber penetrates from the core portion to the skin portion. In the case of the reinforcing fiber shown in FIG. 13 as an example, this is the length of the section indicated by reference numeral 29. The macroscopic boundary surface 33 between component [A] and component [B] refers to the observed boundary between component [A] and component [B]. Specifically, the vicinity of the boundary between component [A] and component [B] in the cross section of the rotor blade is photographed at 1000x magnification using a laser microscope. A line is drawn in the captured image so that the area occupied by the matrix resin of component [A] beyond that line is equal to the area occupied by the matrix resin of component [B] and voids beyond that line. If there are multiple such lines, the line with the largest area in the captured image is included. The cross section of the rotor blade refers to a plane passing through the rotor shaft, leading edge, and trailing edge. The maximum penetration length is the maximum value among the measured penetration lengths. Specifically, the maximum penetration length of the core's reinforcing fibers into the skin can be measured as follows. The joint between the skin and core of the rotor blade is cut out, and 10 random locations (10 images) of the cross section in the thickness direction are photographed at 1,000x magnification using a laser microscope. From the images obtained, the penetration length of each single fiber where the reinforcing fiber in the core penetrates into the skin is determined, and the maximum value is taken as the maximum penetration length.

[0087] Here, thermoplastic resins and thermosetting resins can be exemplified as resin 27. In the present invention, a thermosetting resin and a thermoplastic resin may be blended, and in this case, the resin type of resin 27 is a thermosetting resin or a thermoplastic resin that accounts for more than 50 mass % of the components constituting the resin.

[0088] In one embodiment of the present invention, it is desirable that the resin 27 contains at least one type of thermoplastic resin. Examples of the thermoplastic resin include polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), and liquid crystal polyester; polyolefins such as polyethylene (PE), polypropylene (PP), and polybutylene; polyarylene sulfides such as polyoxymethylene (POM), polyamide (PA), and polyphenylene sulfide (PPS); fluorine-based resins such as polyketone (PK), polyether ketone (PEK), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyether nitrile (PEN), and polytetrafluoroethylene; and liquid crystal polymers (LCPs). Examples of such resins include crystalline resins such as styrene-based resins, polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), polyphenylene ether (PPE), polyimide (PI), polyamideimide (PAI), polyetherimide (PEI), polysulfone (PSU), polyethersulfone, and polyarylate (PAR), as well as phenol-based resins, phenoxy resins, and thermoplastic elastomers such as polystyrene-based, polyolefin-based, polyurethane-based, polyester-based, polyamide-based, polybutadiene-based, polyisoprene-based, fluorine-based resins, and acrylonitrile-based thermoplastic elastomers, as well as copolymers and modified products thereof.

[0089] Among these, polyolefins are desirable from the viewpoint of the light weight of the resulting rotor blades, polyamides are desirable from the viewpoint of strength, amorphous resins such as polycarbonates and styrene-based resins are desirable from the viewpoint of surface appearance, polyarylene sulfides are desirable from the viewpoint of heat resistance, polyetherimides and polyether ether ketones are desirable from the viewpoint of continuous use temperature, and fluororesins are desirable from the viewpoint of chemical resistance.

[0090] In one embodiment of the present invention, the resin 27 preferably includes at least one thermosetting resin. Examples of thermosetting resins include unsaturated polyester, vinyl ester, epoxy resin, phenolic resin, urea resin, melamine resin, thermosetting polyimide, copolymers or modified products thereof, and resins obtained by blending at least two of these. Furthermore, the structure according to the present invention may contain an impact resistance improver such as an elastomer or rubber component, other fillers, or additives, as long as the object of the present invention is not impaired.

[0091] Examples of fillers and additives include inorganic fillers, flame retardants, conductivity imparting agents, crystal nucleating agents, ultraviolet absorbers, antioxidants, vibration dampers, antibacterial agents, insect repellents, deodorizing agents, coloration inhibitors, heat stabilizers, release agents, antistatic agents, plasticizers, lubricants, colorants, pigments, dyes, foaming agents, foam control agents, and coupling agents.

[0092] When the volume of component [B] is taken as 100% by volume, the volume content of resin 27 is preferably in the range of 2.5% by volume or more and 85% by volume or less. If the volume content of resin 27 is less than 2.5% by volume, the reinforcing fibers in the porous body may not be bonded together to fully achieve the reinforcing effect of the reinforcing fibers, which is undesirable because it may result in the mechanical properties of the structure, particularly the bending properties, becoming unsatisfactory. On the other hand, if the volume content of resin 27 is greater than 85% by volume, the amount of resin is too large, which may make it difficult to form a void structure, which is undesirable.

[0093] Examples of reinforcing fibers include metal fibers such as aluminum, brass, and stainless steel; PAN-based, rayon-based, lignin-based, and pitch-based carbon fibers; organic fibers such as aramid, PBO, polyphenylene sulfide, polyester, acrylic, nylon, and polyethylene; and inorganic fibers such as graphite fibers, glass fibers, silicon carbide, and silicon nitride. These fibers may also be surface-treated. Examples of surface treatments include coating with a metal as a conductor, treatment with a coupling agent, treatment with a sizing agent, treatment with a binder, and treatment with an additive. These fibers may be used alone or in combination.

[0094] Among these, PAN-based, pitch-based, and rayon-based carbon fibers, which are excellent in specific strength and specific rigidity, are preferably used from the viewpoint of weight reduction. Also, glass fibers are preferably used from the viewpoint of improving the economic efficiency of the resulting structure, and it is particularly desirable to use a combination of carbon fibers and glass fibers from the viewpoint of a balance between mechanical properties and economic efficiency.

[0095] Furthermore, from the viewpoint of improving the impact absorption and formability of the resulting structure, aramid fibers are preferably used, and in particular, it is desirable to use carbon fibers and aramid fibers in combination from the viewpoint of the balance between mechanical properties and impact absorption. Furthermore, from the viewpoint of improving the electrical conductivity of the resulting structure, metal-coated reinforcing fibers can also be used. Among these, PAN-based carbon fibers, which have excellent mechanical properties such as strength and elastic modulus, are more preferably used.

[0096] Furthermore, it is desirable that the reinforcing fibers contained in component [B] are discontinuous, approximately monofilament-like, and randomly dispersed. By configuring the reinforcing fibers in this manner, when a precursor or a structure of a sheet-like structure is molded by applying an external force, it becomes easy to form a complex shape.

[0097] Furthermore, by configuring the reinforcing fibers in this manner, the voids formed by the reinforcing fibers become denser, and weak parts at the ends of the reinforcing fiber bundles in the porous body can be minimized, thereby imparting isotropy in addition to excellent reinforcing efficiency and reliability.

[0098] Here, "substantially monofilament-like" means that the reinforcing fiber single yarns are present in a fineness strand of less than 500. More preferably, they are dispersed in a monofilament-like state, i.e., in the form of single fibers.

[0099] Specifically, "approximately monofilament-like" or "dispersed in a monofilament-like manner" means that, for arbitrarily selected reinforcing fibers in a porous body, the proportion of single fibers with a two-dimensional contact angle of 1° or more (hereinafter also referred to as "fiber dispersion rate") is 80% or more, or in other words, the proportion of bundles in which two or more single fibers are in contact and parallel in the porous body is less than 20%. Therefore, here, it is particularly preferable that the mass fraction of fiber bundles containing at least 100 filaments in the reinforcing fibers corresponds to 100%.

[0100] In the case of discontinuous reinforcing fibers, the two-dimensional contact angle is the angle formed between a single fiber and a single fiber that it contacts. It is defined as the acute angle between the angles formed between the contacting single fibers, which is in the range of 0° to 90°. This two-dimensional contact angle will be further explained using the drawings. Figure 14 is a schematic diagram showing an example of the dispersion state of reinforcing fibers in a reinforced fiber mat when observed from the surface direction ( Figure 14(a) ) and the thickness direction ( Figure 14(b) ). In Figure 14(a) , a single fiber 30 is observed intersecting with other single fibers, but in Figure 14(b) , a single fiber 30b is not in contact with a single fiber 30c. In this case, the two-dimensional contact angle of the reference single fiber is evaluated as the contacting single fiber 30, and the acute angle A between the two angles formed by the two single fibers, which is in the range of 0° to 90°.

[0101] The method for measuring the two-dimensional contact angle is not particularly limited, but for example, a method of observing the orientation of the reinforcing fibers from the surface of the porous body can be exemplified. In this case, polishing the surface of the rotor blade to expose the reinforcing fibers makes it easier to observe the reinforcing fibers.

[0102] Another example is a method of taking an image of the orientation of the reinforcing fibers by performing X-ray CT transmission observation. In the case of reinforcing fibers with high X-ray transmittance, it is desirable to mix tracer fibers into the reinforcing fibers or to apply a tracer agent to the reinforcing fibers, as this makes it easier to observe the reinforcing fibers. In addition, if measurement is difficult using the above method, an example is a method in which the rotor is heated at high temperature in a heating furnace or the like to burn off the resin component, and then the orientation of the reinforcing fibers is observed from the reinforcing fibers extracted using an optical microscope or electron microscope.

[0103] Based on the observation method described above, the fiber dispersion ratio is measured by the following procedure. Specifically, the two-dimensional contact angles of all single fibers in contact with a randomly selected single fiber (single fiber 30 in FIG. 14) are measured. This is performed for 100 single fibers, and the percentage is calculated from the ratio of the number of single fibers with a two-dimensional contact angle of 1° or more to the total number of all single fibers for which the two-dimensional contact angles have been measured.

[0104] Furthermore, it is particularly desirable that the reinforcing fibers are randomly dispersed. Here, "randomly dispersed reinforcing fibers" means that the arithmetic mean value of the two-dimensional orientation angle of arbitrarily selected reinforcing fibers in the porous body is in the range of 30° to 60°. The two-dimensional orientation angle is the angle formed by a single fiber of the reinforcing fiber 3 and a single fiber intersecting with this single fiber, and is defined as the acute angle between the intersecting single fibers in the range of 0° to 90°.

[0105] This two-dimensional orientation angle will be further explained using the drawings. In Figures 14(a) and 14(b), when a single fiber 30 is taken as a reference, the single fiber 30 intersects with other single fibers. Here, "intersection" refers to a state in which the reference single fiber is observed to intersect with other single fibers in a two-dimensional plane. The single fiber 30 does not necessarily have to be in contact with the other single fibers, and a state in which they are observed to intersect when projected is also included. In other words, when viewed from the reference single fiber 30, all other single fibers are the subject of evaluation for the two-dimensional orientation angle. In Figure 14(a), the two-dimensional orientation angle is angle A, which is the acute angle between the two intersecting single fibers and is in the range of 0° to 90°.

[0106] The method for measuring the two-dimensional orientation angle is not particularly limited, and an example is a method in which the surface of the component [B] is exposed and the orientation of the reinforcing fibers is observed from that surface. A method similar to the above-mentioned method for measuring the two-dimensional contact angle can be used. The average value of the two-dimensional orientation angle is measured by the following procedure. That is, the average value of the two-dimensional orientation angles of all the single fibers intersecting a randomly selected single fiber (single fiber 30 in FIG. 14) is measured. For example, when a large number of other single fibers intersect a certain single fiber, the arithmetic average value measured by randomly selecting 20 other intersecting single fibers may be used instead. This measurement is repeated a total of five times using the other single fibers as the reference, and the arithmetic average value is calculated as the arithmetic average value of the two-dimensional orientation angle.

[0107] By dispersing the reinforcing fibers in a substantially monofilament shape and randomly, it is possible to maximize the performance provided by the reinforcing fibers dispersed in a substantially monofilament shape. Furthermore, it is possible to impart isotropy to the mechanical properties of the porous body. From this perspective, the fiber dispersion rate of the reinforcing fibers is preferably 90% or more, and the closer it is to 100%, the more desirable it is. Furthermore, it is desirable that the arithmetic mean value of the two-dimensional orientation angle of the reinforcing fibers be in the range of 40° or more and 50° or less, and the closer it is to the ideal angle of 45°, the more desirable it is.

[0108] On the other hand, examples of reinforcing fibers that do not take the form of a nonwoven fabric include sheet substrates, woven substrates, non-crimp substrates, etc., in which the reinforcing fibers are arranged in one direction. In these forms, the reinforcing fibers are regularly and densely arranged, which reduces the voids in the porous body, making resin impregnation extremely difficult, resulting in the formation of unimpregnated areas, or significantly limiting the options for impregnation methods and resin types.

[0109] The form of the reinforcing fibers in the component [B] is preferably discontinuous reinforcing fibers, from the viewpoint of facilitating resin impregnation and facilitating adjustment of the amount of resin.

[0110] The volume content of the reinforcing fibers is preferably in the range of 0.5% by volume or more and 55% by volume or less. If the volume content of the reinforcing fibers is less than 0.5% by volume, the reinforcing effect derived from the reinforcing fibers may not be sufficient. On the other hand, if the volume content of the reinforcing fibers is greater than 55% by volume, the volume content of the resin relative to the reinforcing fibers becomes relatively small, so the reinforcing fibers in the porous body are bonded together, and the reinforcing effect of the reinforcing fibers cannot be made sufficient, and the mechanical properties, particularly the bending properties, of the porous body may not be satisfied.

[0111] The reinforcing fibers are coated with resin, and the thickness of the resin, i.e., the length of the portion where only resin is present without any reinforcing fibers, is preferably in the range of 1 μm to 15 μm. The coating state of the resin-coated reinforcing fibers is sufficient from the standpoint of shape stability of the porous body and ease and freedom of thickness control, as long as at least the intersection points of the reinforcing fibers constituting the porous body are coated. However, in a more desirable embodiment, the resin is preferably coated around the reinforcing fibers to the above-mentioned thickness. This state means that the surface of the reinforcing fibers is not exposed by the resin; in other words, the reinforcing fibers form a wire-like coating with the resin. This further ensures that the porous body has shape stability and sufficient mechanical properties. Furthermore, the coating state of the resin-coated reinforcing fibers does not need to be such that all of the reinforcing fibers are coated; it is sufficient as long as it does not impair the shape stability, flexural modulus, or flexural strength of the porous body of the present invention.

[0112] In the rotor blade of the present invention, the mass average fiber length of the reinforcing fibers contained in component [B] is in the range of 1 mm or more and 15 mm or less. This increases the reinforcing efficiency of the reinforcing fibers, and provides the porous body with excellent mechanical properties. If the mass average fiber length of the reinforcing fibers is less than 1 mm, voids cannot be efficiently formed in the porous body, resulting in a high specific gravity. In other words, it is difficult to obtain a porous body of the desired thickness for the same mass.

[0113] On the other hand, if the mass average fiber length of the reinforcing fibers is longer than 15 mm, the reinforcing fibers will be easily bent under their own weight in the porous body, which will hinder the development of mechanical properties. More preferably, it is 1.5 mm or more and 12 mm or less, and even more preferably, it is 2 mm or more and 11 mm or less. The mass average fiber length can be calculated by removing the resin component of the porous body by methods such as burning or elution, randomly selecting 400 fibers from the remaining reinforcing fibers, measuring their lengths to the nearest 10 μm, and calculating the average length.

[0114] In the present invention, component [B] is a porous body containing voids, i.e., areas where no substances other than gas are present. Examples of such voids include spaces formed when resin-coated reinforcing fibers function as columnar supports and overlap or intersect with each other. For example, when a porous body is obtained by heating a precursor of a porous body in which reinforcing fibers are pre-impregnated with resin, the resin melts or softens with heating, causing the reinforcing fibers to raise, forming voids. This is due to the tendency of the internal reinforcing fibers, which have been compressed by pressure in the porous body precursor, to raise due to the raising force resulting from their elastic modulus.

[0115] The void content in the porous body is preferably in the range of 10% by volume or more and 97% by volume or less. If the void content is less than 10% by volume, the specific gravity of the porous body becomes high, and the lightweight property may not be satisfied.

[0116] On the other hand, if the void content is greater than 97% by volume, in other words, the thickness of the resin coating around the reinforcing fibers becomes thin, and the reinforcing fibers in the porous body are not sufficiently reinforced, which may result in poor mechanical properties. Therefore, the upper limit of the void content is preferably 97% by volume. In the present invention, the void content is calculated as a volume content, and the sum of the volume contents of the resin, reinforcing fibers, and voids that make up the porous body is taken as 100% by volume.

[0117] When the bending modulus of the porous body is Ec and the specific gravity of the structure 1 is ρ, Ec １／３ ・ρ －１The specific bending rigidity of the porous body, expressed as , is preferably in the range of 3 or more and 20 or less. When the specific bending modulus of the porous body is less than 3, even if the bending modulus is high, the specific gravity is also high, and the desired weight reduction effect may not be obtained, which is undesirable. On the other hand, when the specific bending modulus of the porous body is greater than 20, although the weight reduction effect is sufficient, it indicates that the bending modulus is low, which is undesirable because it is difficult to maintain the desired shape of the porous body or the bending modulus of the porous body itself may be poor.

[0118] Generally, the specific bending stiffness of steel and aluminum is 1.5 or less, which is a range of the specific bending modulus that is far superior to these metallic materials. Furthermore, the specific bending modulus of carbon fiber reinforced resin composite materials, which are noted for their weight reduction effect, is 2.3, which is greater than 3 or more, and more preferably 5 or more.

[0119] The flexural modulus Ec of the porous body is preferably 3 GPa or more, preferably 6 GPa or more. If the flexural modulus Ec of the porous body is less than 3 GPa, it is undesirable because it limits the range of use of the porous body. In addition, to facilitate the design of the porous body, it is desirable for the flexural modulus to be isotropic. Although there is no upper limit on the flexural modulus, in general, for a structure consisting of reinforcing fibers and resin, the upper limit can be the value calculated from the elastic modulus of the reinforcing fibers and resin, which are its constituent components.

[0120] The specific gravity ρ of the porous body is 0.9 g / cm ３ It is desirable that the specific gravity ρ of the porous body is 0.9 g / cm or less. ３ If the specific gravity is larger than this, it means that the mass of the porous body will increase, which is undesirable because it will result in an increase in the mass of the rotor. There is no lower limit for the specific gravity, but in general, for a porous body made of reinforcing fibers and resin, the value calculated from the volume proportions of the reinforcing fibers, resin, and voids that are its constituent components can be the lower limit. In the rotor according to the present invention, from the viewpoint of maintaining the mechanical properties, a specific gravity of 0.03 g / cm is set. ３ It is desirable that this is the case.

[0121] The reinforcing fibers in component [B] of the present invention preferably have a nonwoven fabric-like form from the viewpoint of ease of resin impregnation into the reinforcing fibers. Having a nonwoven fabric-like form is desirable because it not only makes the nonwoven fabric itself easier to handle, but also facilitates impregnation even in the case of thermoplastic resins that are generally considered to have high viscosity. Here, the nonwoven fabric-like form refers to a form in which reinforcing fiber strands and / or monofilaments are dispersed irregularly in a planar form, and examples thereof include chopped strand mats, continuous strand mats, papermaking mats, carding mats, and airlaid mats (hereinafter collectively referred to as reinforcing fiber mats).

[0122] As a method for producing a reinforcing fiber mat constituting a porous body, for example, there is a method in which reinforcing fibers are dispersed in advance in the form of strands and / or approximately monofilaments to produce a reinforcing fiber mat.

[0123] Known techniques for producing a reinforcing fiber mat include dry processes such as the airlaid method, in which reinforcing fibers are dispersed into a sheet using an air flow, and the carding method, in which reinforcing fibers are mechanically combed to shape them into a sheet, and wet processes such as the Radlite method, in which reinforcing fibers are stirred in water to make paper.

[0124] In the dry process, examples of means for making the reinforcing fibers closer to a monofilament state include providing a fiber-opening bar, vibrating the fiber-opening bar, making the card mesh finer, and adjusting the rotation speed of the card.

[0125] In the wet process, examples include a method of adjusting the stirring conditions of the reinforcing fibers, a method of diluting the reinforcing fiber concentration in the dispersion, a method of adjusting the viscosity of the dispersion, and a method of suppressing vortex flow when transferring the dispersion.

[0126] In particular, it is desirable to produce reinforced fiber mats using a wet process, and the proportion of reinforcing fibers in the reinforced fiber mat can be easily adjusted by increasing the concentration of the input fibers or adjusting the flow rate (flow rate) of the dispersion and the speed of the mesh conveyor. For example, by slowing the speed of the mesh conveyor relative to the flow rate of the dispersion, the orientation of the fibers in the resulting reinforced fiber mat becomes less likely to be in the take-up direction, making it possible to produce a bulky reinforced fiber mat. The reinforced fiber mat may be composed of a single reinforcing fiber, or the reinforcing fiber may be mixed with a powder or fibrous matrix resin component, the reinforcing fiber may be mixed with an organic or inorganic compound, or the reinforcing fiber may be sealed with a resin component.

[0127] Furthermore, the reinforcing fiber mat can be pre-impregnated with a resin to form a porous body precursor. From the viewpoint of ease of production, a preferred method for producing the porous body precursor of the present invention is to apply pressure to a reinforcing fiber mat heated to a temperature above the melting or softening temperature of the resin, thereby impregnating the reinforcing fiber mat. Specifically, a preferred example of a method is to melt and impregnate a laminate in which the resin is arranged on both sides of the reinforcing fiber mat in the thickness direction.

[0128] As equipment for implementing each of the above methods, a compression molding machine or a double belt press can be suitably used. In the case of a batch type, the former is used, and productivity can be improved by using an intermittent press system in which two or more machines, one for heating and one for cooling, are arranged in parallel. In the case of a continuous type, the latter is used, and continuous processing can be easily performed, so continuous productivity is excellent.

[0129] When producing the porous body according to the present invention, it is preferable to employ a method comprising at least the following steps [1] and [2] from the viewpoint of ease of production. Step [1]: A step of applying pressure while heated to a temperature above the melting or softening temperature of the resin to impregnate the reinforcing fiber mat with the resin to produce a porous body precursor. Step [2]: A step of expanding the porous body precursor by adjusting the thickness while heated.

[0130] Step [2] is a step of expanding the porous body precursor obtained in step [1] by adjusting its thickness while it is heated. When the resin constituting the porous body is a thermoplastic resin, it is preferable to apply a heat quantity sufficient to melt or soften it from the viewpoint of thickness control and production speed of the porous body to be produced. Specifically, it is preferable to apply a temperature that is 10°C or more higher than the melting temperature and below the thermal decomposition temperature of the thermoplastic resin. Furthermore, when a thermosetting resin is used as the resin, it is preferable to apply a heat quantity sufficient to melt or soften the thermosetting resin raw material before it forms a crosslinked structure and hardens from the viewpoint of thickness control and production speed of the porous body to be produced.

[0131] The thickness control method is not limited as long as it can control the heated structure precursor to the desired thickness, but preferred methods from the viewpoint of ease of production include a method of constraining the thickness using a metal plate or the like, and a method of controlling the thickness by applying pressure to the structure precursor. As equipment for realizing the above method, a compression molding machine or a double belt press can be suitably used. In the case of a batch type, the former is used, and productivity can be improved by using an intermittent press system in which two or more machines, one for heating and one for cooling, are arranged in parallel. In the case of a continuous type, the latter is used, and continuous processing can be easily performed, resulting in excellent continuous productivity.

[0132] The timing for forming the cut portion is not particularly limited, and the cut portion may be formed in the porous precursor at the stage of step [1], or the cut portion may be formed in the porous body obtained in step [2]. Alternatively, when the porous precursor or the porous body divided in advance in step [2] or later is molded together with the component [A], a cut portion may be formed in which the component [A] has penetrated into the component [B].

[0133] The timing for forming the uneven portion is preferably after step [2] from the viewpoint of the shape retention of the uneven portion, and if the uneven portion is formed before step [2], there is a risk that the uneven portion will become smooth when expanded. An example of a method for implementing this method is a method in which the porous precursor obtained in step [1] is expanded to fit a mold having an uneven shape.

[0134] Examples of reinforced fiber mats that do not take the form of a nonwoven fabric include sheet substrates, woven substrates, and non-crimp substrates, in which the reinforcing fibers are arranged in one direction. In these forms, the reinforcing fibers are regularly and densely arranged, resulting in few voids in the reinforced fiber mat and insufficient anchoring structures for the thermoplastic resin. Therefore, using such a mat as a core-forming layer reduces bonding ability. Furthermore, when the resin is a thermoplastic resin, impregnation becomes extremely difficult, resulting in unimpregnated areas and significantly limiting the options for impregnation methods and resin types.

[0135] The present invention will be described in more detail below with reference to examples, but the present invention should not be construed as being limited to these specific examples.

[0136] (1) Density ρf of reinforcing fiber The density ρf of the reinforcing fiber was measured by the liquid displacement method of JIS R7603 (1999) Method A.

[0137] (2) Density ρr of Resin Sheet The density ρr of the resin sheet was measured by the JIS K7112 (1999) Method A water displacement method.

[0138] (3) Volume content Vf of reinforcing fibers in porous body After measuring the mass Ws of the porous body, the porous body was heated in air at 500°C for 30 minutes to burn off the resin component, and the mass Wf of the remaining reinforcing fibers was measured and calculated using the following formula: Vf (volume %) = (Wf / ρf) / {Wf / ρf+(Ws-Wf) / ρr}×100, where ρf is the density of the reinforcing fibers (g / cm ３ ) ρr: Density of resin sheet (g / cm ３ ).

[0139] (4) Density ρ of Porous Body A test piece was cut out from the porous body, and the apparent density of the porous body was measured with reference to JIS K7222 (2005). The dimensions of the test piece were 100 mm in length and 100 mm in width. The length, width, and thickness of the test piece were measured with a micrometer, and the volume V of the test piece was calculated from the obtained values. In addition, the mass M of the cut-out test piece was measured with an electronic balance. The density ρ of the porous body was calculated by substituting the obtained mass M and volume V into the following equation. ρ [g / cm ３ ]=10 ３ × M [g] / V [mm ３ ].

[0140] (5) Bending test of porous body Test specimens were cut out from the porous body, and the flexural modulus was measured according to ISO 178 (1993). Test specimens were cut out in four directions, 0°, +45°, -45°, and 90°, assuming that an arbitrary direction was the 0° direction, and the number of measurements for each direction was n=5, and the arithmetic average value was taken as the flexural modulus Ec. The measuring device used was an "Instron (registered trademark)" 5565 type universal material testing machine (manufactured by Instron Japan Co., Ltd.). The specific flexural rigidity of the structure was calculated from the obtained results using the following formula: Specific flexural rigidity = Ec １／３ ・ρ －１ .

[0141] (6) Volume content of voids in porous body A test piece measuring 10 mm in length and 10 mm in width was cut out from the porous body, and the cross section was observed using a scanning electron microscope (SEM) (Hitachi High-Technologies Corporation, S-4800 model). Photographs were taken at 10 equally spaced locations on the surface of the porous body at a magnification of 1,000 times. For each image, the area Aa of the voids in the image was determined. Furthermore, the porosity was calculated by dividing the area Aa of the voids by the area of ​​the entire image. The volume content of voids in the porous body was determined by the arithmetic average of the porosities of a total of 50 locations, each photographed at 10 locations on five test pieces. The arithmetic average of these values ​​is the average porosity. When the porous body is divided into three parts, the volume fraction of voids in the divided parts is measured by dividing the porous body into three parts at a plane perpendicular to the line connecting the leading edge and the trailing edge at a point from the tip to the root so that the divided parts have equal volumes, and cutting a test piece measuring 10 mm in length and 10 mm in width from each divided part along the line connecting the leading edge and the trailing edge. The volume fraction of voids is measured in the same way as described above.

[0142] (7) Volume content of resin in porous body The sum of the volume contents of the reinforcing fibers and voids obtained above was subtracted from 100% by volume to obtain the volume content of resin.

[0143] (8) Maximum penetration length of reinforcing fiber into skin The joint between the skin and core of the rotor blade was cut out, and its thickness direction cross section was photographed at 1,000x magnification using a laser microscope (VK-9510 manufactured by Keyence Corporation) at 10 arbitrary locations (10 images). From the obtained images, the penetration length of each single fiber where the reinforcing fiber in the core penetrated into the skin was determined based on the macro boundary surface, and the maximum value was taken as the maximum penetration length. The macro boundary surface was determined by drawing a line in the image photographed at 1,000x magnification so that the area occupied by the matrix resin of component [A] existing beyond the line was equal to the area occupied by the matrix resin of component [B] and voids existing beyond the line, and the plane including the line and extending in the depth direction of the image was taken as the macro boundary surface.

[0144] (9) [Carbon Fiber] A copolymer containing polyacrylonitrile as the main component was spun, baked, and surface-oxidized to obtain a continuous carbon fiber with a total of 12,000 single fibers. The properties of this continuous carbon fiber were as follows: Single fiber diameter: 7 μm Density: 1.8 g / cm ３ Tensile strength: 4,600 MPa Tensile modulus: 220 GPa.

[0145] (10) [PP resin] 80% by mass of unmodified polypropylene resin (Prime Polypro® J105G manufactured by Prime Polymer Co., Ltd.) and 20% by mass of acid-modified polypropylene resin (Admer® QB510 manufactured by Mitsui Chemicals, Inc.) with a basis weight of 100 g / m ２ The density of the obtained PP resin sheet was 0.92 g / cm ３ It was.

[0146] (11) [Reinforced Fiber Mat] The carbon fibers obtained in (9) [Carbon Fiber] were cut to a length of 6 mm to obtain chopped carbon fibers (CF1). The chopped carbon fibers were fed into a cotton opener to obtain a cotton-like reinforcing fiber aggregate with almost no reinforcing fiber bundles of the original thickness. This reinforcing fiber aggregate was fed into a carding machine having a cylinder roll with a diameter of 600 mm to form a sheet-like web made of reinforcing fibers. The rotation speed of the cylinder roll was 320 rpm, and the doffer speed was 13 m / min. This web was stacked to obtain a reinforcing fiber mat 1. In the obtained reinforcing fiber mat 1, the reinforcing fibers were dispersed in a substantially monofilament-like manner. Furthermore, the mass average fiber length Lf of the reinforcing fiber mat 1 was 6 mm, and the basis weight was 50 g / m. ２ It was.

[0147] (12) [Porous Body Precursor] A laminate was produced by stacking three laminates, each consisting of a reinforced fiber mat 1 and a resin sheet of PP resin, arranged in the following order: [resin sheet / reinforced fiber mat / resin sheet / reinforced fiber mat / resin sheet / reinforced fiber mat / resin sheet / reinforced fiber mat / resin sheet / reinforced fiber mat / resin sheet / reinforced fiber mat / resin sheet / reinforced fiber mat / resin sheet]. Next, a porous body precursor was obtained by the following steps (I) to (III). (I) The laminate was placed in a press molding die cavity (flat plate shape) preheated to 230°C, and the die was closed. (II) Next, after holding for 120 seconds, a pressure of 3 MPa was applied and held for an additional 60 seconds. (III) While maintaining the pressure, the cavity temperature was cooled to 50°C, and the porous body precursor was removed.

[0148] (13) [Porous Body] A porous body precursor was designed to have a predetermined shape and mass, and a porous body was obtained by carrying out the following steps (I) to (III). (I) The laminate was placed in a press molding die cavity (rotor blade shape) preheated to 230°C, and the die was closed. (II) Next, after holding for 120 seconds, a pressure of 3 MPa was applied and held for an additional 60 seconds. (III) While maintaining the pressure, the cavity temperature was cooled to 50°C, and the resulting porous body was removed.

[0149] In the obtained porous body, voids formed by columnar supports of reinforcing fibers were confirmed from cross-sectional observation.

[0150] As porous bodies, core 1, core 2 having a 1 mm deep cut portion that accounted for 5% by volume of core 2, core 3 having a 2 mm deep cut portion that accounted for 15% by volume of core 3, and core 4 having a 0.1 mm deep concave-convex portion formed on the surface were prepared. The concave-convex portion was formed by embossing the mold used in steps (I) to (III). As a comparative example, core 5 having a 1 mm deep cut portion that accounted for 5% by volume of core 5, similar to core 2, was prepared using a low-foam polypropylene sheet "EFCEL" (registered trademark) manufactured by Furukawa Electric Co., Ltd. instead of component [B]. Core 6 having a cut portion similar to component core 1 was also prepared using a low-foam polypropylene sheet "EFCEL" (registered trademark) manufactured by Furukawa Electric Co., Ltd.

[0151] (14) Manufacturing of Rotor A carbon fiber reinforced prepreg was cut to fit the shape of the rotor. The prepregs used were "TORAYCA" (registered trademark) prepreg P2362W-19 (unidirectional prepreg) and FM6673G-37 (woven fabric prepreg) manufactured by Toray Industries, Inc. A specific lamination structure for component [A] was such that one layer of the unidirectional prepreg (PPg1) was laminated on the inner side of the woven fabric material (PPg2), i.e., on the side intended to form component [B]. The longitudinal direction of the rotor was set to 0°, and the woven fabric material was laminated at ±45°, and the unidirectional material was laminated at 0°. For component [C] and component [D], PPg1 was laminated so that the fiber orientation was in the same direction.

[0152] The cut prepreg was layered on the porous body 1, and a rotor was obtained by carrying out the following steps (I) to (III). The laminate structure was woven prepreg / unidirectional prepreg / porous body / unidirectional prepreg / woven prepreg. (I) The laminate was placed in a press molding die cavity (rotor shape) preheated to 180°C, and the die was closed. (II) Next, after holding for 10 minutes, a pressure of 3 MPa was applied and held for an additional 2 hours. (III) While maintaining the pressure, the cavity temperature was cooled to 50°C, and the porous body precursor was removed.

[0153] (15) Evaluation of Positional Accuracy of Component [D] A cross section of the rotor blade was cut out, and the positional accuracy of the component [D] was observed at a magnification of 50 times using a laser microscope (VK-9510 manufactured by Keyence Corporation), and the positional accuracy was measured when the leading edge and the trailing edge tips of the molded product were aligned with the design drawing.

[0154] Specifically, when 20 molded products were molded, those in which the positional accuracy of the component [D] relative to the target position, starting from the leading edge, was within 1 / 20 of the distance connecting the leading edge and the trailing edge were judged to be passable. If 18 to 20 products passed, they were rated as S (Excellent), if 14 to 17 products passed, they were rated as A (Good), if 10 to 13 products passed, they were rated as B (Average), and if less than 10 products passed, they were rated as C (Poor).

[0155] (16) Rc (resin mass content) of prepreg The Rc of the prepreg was determined according to JIS K7071 (1988).

[0156] (17) Glass transition temperature after molding A 2 mm thick molded product was molded under the same molding conditions as for the impeller, and a test piece 12.7 mm wide and 45 mm long was cut out. Using a viscoelasticity measuring device (ARES, manufactured by TA Instruments), DMA measurement was performed in the temperature range of 30 to 250°C under conditions of a torsional vibration frequency of 1.0 Hz and a heating rate of 5.0°C / min. The glass transition temperature (Tg) was defined as the temperature at the intersection of the tangent in the glassy state and the tangent in the transition state on the storage modulus G' curve.

[0157] Examples 1 to 5 Table 1 lists the components [A], [C], and [D], and the prepreg used for the component [D], and Table 2 lists the porous body used for the component [B]. Rotors were manufactured with the configuration shown in Table 3. Representative cross sections of the rotors are also shown. In Example 1, a porous core 1 was used and configured as shown in FIG. 2 . In Example 2, a porous core 2 was used and the porous body was provided with the notches shown in FIG. 4 , resulting in a rotor with the configuration shown in FIG. 7 , i.e., including the components [C] and [D]. In Example 3, a porous core 2 was used and the porous body was provided with the notches shown in FIG. 4 , resulting in a rotor with the configuration shown in FIG. 11 , i.e., a hollow portion was provided and the component [E] was provided in the hollow portion. In Example 4, a porous core 4 was used and configured as shown in FIG. 16 , and a concave-convex portion having the depth indicated by the reference numeral 32 was formed in the component [B]. In Example 5, a porous core 1 was used and a rotor with the configuration shown in FIG. 17 was molded. In Example 5, component [A] containing component [B] made of multiple porous precursors was integrally molded without going through a porous body. That is, instead of the above-mentioned (13) [Porous body] and (14) [Rotor blade manufacturing process], component [A] cut into a predetermined shape and arranged on the wall surface of a mold, then a porous body precursor for component [B] was placed in the mold, and steps (I) to (III) of (13) [Porous body] were performed to obtain a molded product in which component [A] and component [B] were integrated. Note that by adjusting the wall surface of the mold, a cut portion as shown by reference numeral 11 was formed.

[0158] (Comparative Examples 1 and 2) Table 1 shows the prepreg used for component [A], and a low-foam polypropylene sheet "EF-CELL" (registered trademark) manufactured by Furukawa Electric was used instead of component [B]. A representative cross section of the rotor is also shown. Core 6 had a cutout similar to that of core 2.

[0159] A comparison of the core materials of Example 1 and Comparative Example 1 shows that they are equally lightweight, but in Example 1, the specific bending strength of the component [B] used in the core is high, and not only is the rigidity of the rotor high, but the reinforcing fibers of the component [B] penetrate the core, so that the adhesiveness is high and the fatigue characteristics can be dramatically improved.

[0160] Furthermore, a comparison of Example 2 and Comparative Example 2, in which the notches are present, shows that the positional accuracy of the component [D] is higher in Example 2, which uses the component [B], and as a result, a rotor blade exhibiting stable fatigue characteristics can be manufactured. Furthermore, the presence of the notches provides even higher adhesiveness, resulting in excellent fatigue characteristics over a long period of time.

[0161] Furthermore, a comparison of the core materials of Example 2, in which a notch was made in the core, and Comparative Example 3 revealed that Core 6 of Comparative Example 3, which was made by making a notch in the core, broke at the notch after step (III), and the flexural modulus could not be measured.

[0162] Example 3 shows a molded product which further has a hollow portion in addition to the components of Example 2, and the hollow portion can be manufactured with high positional accuracy.

[0163] The rotor of the present invention can be suitably applied to air mobility such as drones and flying cars (unmanned and manned) and wind turbines.

[0164]

[0165]

[0166]

[0167] 1: Example of a rotor 2: Central axis when the rotor rotates 3: Distance between the central axis and the tip of the rotor 4: Center of the distance between the central axis and the tip of the rotor shaft 5: Longitudinal direction of the rotor 6: Example of a cross section of a rotor 7: Skin constituting the surface of the rotor 8: Core constituting the interior of the rotor 9: Reinforcement portion 10: Step 11: Cut 12: Length of cut 13: Leading edge 14: Trailing edge 15: Example of a cut in the longitudinal direction 16: Straight line connecting the leading edge and the trailing edge 17: Center of the line connecting the leading edge and the trailing edge, and cross section perpendicular to it 18: Continuity portion (girder portion) 19: Joint 20: Angle of joint 21: Hollow portion 22: Internal reinforcing layer 23: Example shape of the hollow portion 24: Matrix resin of component [A] 25: Void of component [B] 26: Reinforcing fiber of component [B] 27: Resin of component [B] 28: Reinforcing fiber of component [B] penetrating the matrix resin of component [A] 29: Penetration length of reinforcing fiber of component [B] 30: Single fiber 31: Concave and convex portion 32: Distance between convex and concave portions 33: Macro boundary between component [A] and component [B] 34: Division line when porous body is divided into three equal volumes

Claims

1. A rotor including the following component [A] constituting at least a skin which is a surface layer of the rotor, and the following component [B] constituting a core which is an interior of the skin, wherein component [B] is contained within component [A] at least in a cross section taken at the center between a central axis and a tip of the rotor during rotation. Component [A]: Continuous fiber substrate containing continuous reinforcing fibers and matrix resin Component [B]: A porous body containing reinforcing fibers and a resin, wherein the reinforcing fibers have a mass average fiber length of 1 mm or more and 15 mm or less.

2. 2. The rotor according to claim 1, wherein, at least in a cross section at the center between the central shaft and the tip of the rotor during rotation, the following component [C] is arranged as a reinforcing layer having a thickness different from that of the component [A], the reinforcing layer is arranged over at least 50% or more of a section from the central shaft to the tip of the rotor in the longitudinal direction of the rotor, and the component [B] is anchored along a step portion having a different thickness. Component [C]: Continuous fiber substrate containing continuous reinforcing fibers and matrix resin

3. 3. The rotor according to claim 1 or 2, wherein, in a cross section at least at the center between the central shaft and the tip of the rotor during rotation, when the outer layer is uniformly scraped away over a range of 0.05 to 10 mm from the outermost portion forming the rotor, excluding 5 mm each of a leading edge and a trailing edge, component [B] has a cut-out portion of 0.1 mm or more covering at least 50% or more of the longitudinal direction of the rotor, and component [A] has penetrated into the cut-out portion.

4. 3. The rotor according to claim 1 or 2, wherein, in a cross section at least at the center between the central shaft and the tip of the rotor during rotation, when the outer layer is uniformly scraped away over a range of 0.05 to 10 mm from the outermost portion forming the rotor, excluding 5 mm each of a leading edge and a trailing edge, component [B] has uneven portions having a depth or height of 0.05 mm or more covering at least 50% or more of the rotor in the longitudinal direction, and component [A] has penetrated into the uneven portions.

5. 3. The rotor according to claim 1 or 2, wherein, in a cross section at least at the center between the central axis and the tip of the rotor during rotation, the average porosity of the porous portion of the component [B] is in the range of 10 volume % or more and 97 volume % or less, and when the rotor is divided into three sections with equal volumes by planes orthogonal to a line connecting the leading edge and the trailing edge, the maximum average porosity and the minimum average porosity differ by 3 volume % or more.

6. 3. The rotor according to claim 1 or 2, further comprising a component [D] forming a continuous portion connecting the component [A] at least in a cross section at the center between the central axis and the tip of the rotor during rotation. Component [D]: Continuous fiber substrate containing continuous reinforcing fibers and matrix resin

7. The rotor according to claim 6, wherein the thickness of the component [D] changes continuously at a joint with the component [A] that constitutes the skin of the rotor, the angle R at which the thickness changes is formed with a radius of 1 to 100 mm, and the component [B] is anchored along the shape formed by the angle R.

8. 3. The rotor according to claim 1, wherein the rotor has a hollow portion of at least 1 mm in cross section at least at the center between the central axis and the tip of the rotor during rotation.

9. 9. The rotor of claim 8, further comprising an internal reinforcing layer of component [E] disposed in the hollow portion. Component [E]: Continuous fiber substrate containing continuous reinforcing fibers and matrix resin

10. 3. The rotor according to claim 1, wherein the reinforcing fibers constituting the component [B] are substantially monofilament-shaped and are randomly dispersed in the porous body.

11. When the flexural modulus of the component [B] is Ec and the density is ρ, Ec １／３ ・ρ －１ 3. The rotor according to claim 1, wherein the specific bending stiffness expressed by the following formula is in the range of 3 or more and 20 or less.

12. 3. The rotor according to claim 1 or 2, wherein a part of the reinforcing fibers constituting the component [B] penetrates a part of the component [A], and the maximum penetration length is 5 μm or more.

13. Air mobility using the rotor according to claim 1 or 2.