JP4044462B2 - Rotor aircraft rotor hub structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotor hub structure of a rotary wing aircraft, and more particularly to a rotor hub structure of a rotary wing aircraft that is preferably used for a medium-sized or large-sized rotary wing aircraft.
[0002]
In the present invention, the term “substantially U shape” includes “U shape”, the term “substantially vertical direction” includes “vertical direction”, the term “substantially orthogonal” includes “perpendicular”, and the term “substantially parallel”. "Includes" parallel ".
[0003]
[Prior art]
Conventionally, as a rotor hub structure of a rotary wing aircraft, a structure using a bearingless structure and an elastomeric bearing has been put into practical use. The bearingless structure is a structure in which the flapping motion, the dragging motion, and the feathering motion of the rotor blade are performed by elastic deformation of the yoke of the rotor blade, and is applied to, for example, small and medium-sized machines. With this structure, the yoke of the rotor blade is repeatedly elastically deformed.
[0004]
As a rotor hub structure that prevents elastic deformation of the yoke of the rotor blade, there is a structure using an elastomeric bearing. Elastomeric bearings are composed of a plurality of metal shims (thin plates) and a plurality of rubber layers (elastic layers) that can be alternately stacked to allow a compressive load acting in the direction of the layers, and elastic deformation of the rubber layers. Can be allowed to swing within a predetermined angle range, and the hub structure using this is applied to, for example, large machines.
[0005]
FIG. 16 is a cross-sectional view showing a conventional rotor hub structure 1 using an elastomeric bearing. The rotor hub structure 1 is configured by two upper and lower plates 3 and 4 being connected by a connecting bolt 5, a supporting member 2 is provided on the connecting bolt 5, and an elastomeric bearing 7 is provided on the supporting member 2. . In such a rotor hub structure 1, the rotor blade 8 is connected to the elastomeric bearing 7 (see, for example, Patent Document 1).
[0006]
FIG. 17 is a cross-sectional view showing another conventional rotor hub structure 10 using an elastomeric bearing. In the rotor hub structure 10, an annular and belt-shaped reinforcing girdle 12 is provided on a cylindrical mast 11, an elastomeric bearing 13 is provided on the reinforcing girdle 12, and a support member 14 is provided on the elastomeric bearing 13. Configured. In such a rotor hub structure 10, the rotor blade 15 is coupled to the support member 14 (see, for example, Patent Document 2).
[0007]
[Patent Document 1]
Special Table 2000-510791
[Patent Document 2]
JP-A-62-20797
[0008]
[Problems to be solved by the invention]
In the rotor hub structure 1 shown in FIG. 16, the plates 3 and 4 to which the rotor blades 8 are connected support the rotor blades 8 against the centrifugal force applied from the rotor blades 8 in the radially outward direction R0. Since the plate 3 has a central depression and the lower plate 4 is formed in a truncated truncated cone with the central portion protruding downward, it is not in a shape suitable for resisting centrifugal force. In this way, the structure is less efficient in strength, and the structure becomes wasteful. Moreover, it is necessary to use the bolt 5 which fastens the plates 3 and 4 and the support member 2 in the part to which a big centrifugal force is added. The bolt 5 needs to be strong enough to withstand a large centrifugal force, which increases the size of the bolt 5 and the accompanying peripheral components and increases the weight. Further, in the configuration using the bolt 5, the reliability is lowered due to an increase in the number of parts.
[0009]
In the rotor hub structure 10 shown in FIG. 17, for example, centrifugal force in the radially outward direction R1, which is a very large force of several tens of tons, is transmitted to the mast 11, and the hoop force of the mast 11 against the centrifugal force. Therefore, the rotor blade 15 must be supported. In this way, the structure is less efficient in strength, and the structure becomes wasteful.
[0010]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a rotor hub structure for a rotorcraft having a highly reliable structure and a highly efficient structure with little waste.
[0011]
[Means for Solving the Problems]
  The present invention according to claim 1 is a rotor hub structure in which a plurality of rotor blades are coupled,
  In a plane orthogonal to the rotor rotation axis, each of the plurality of arm portions is formed in a substantially U shape that opens radially inward, and is arranged radially when viewed in the rotation axis direction of the rotor. By the composite material including the fiber reinforcement material, the arm portions are provided so as to be continuous at the radially inner end, and at least some of the fiber reinforcement materials extend over the plurality of arm portions and are arranged in a loop shape. A centrifugal force support that forms a loop by integrally forming the arm portion of the
  A first blade supporting bearing means provided on the radially inner side of each arm portion and supported by each arm portion, and a yoke provided on the radially inner end portion of the rotor blade as a flap, a lead lug , Radial direction in a state that allows angular displacement in the feathering directionInsideAn elastomeric first blade supporting bearing means, which is supported from the opposite side and is formed by laminating an elastic body and a rigid body;
  A cylindrical rotor mast to which rotational force is transmitted from the prime mover,
  The first blade supporting bearing means is a rotor hub structure for a rotary wing aircraft, characterized in that the first blade supporting bearing means is disposed in the vicinity of the virtual cylindrical surface where the rotor mast is disposed and inward of the virtual cylindrical surface.
[0012]
  According to the present invention, in the rotor hub structure in which a plurality of rotor blades are connected, the centrifugal force support body is formed integrally with a plurality of arms by a composite material. Each arm part is provided with a first blade supporting bearing means of an elastomeric type. By this first blade support bearing means, the yoke provided on the rotor blade is in the radial direction.InsideSupported from the other side. With this configuration, the centrifugal force acting on the rotor blade can be transmitted to the integral centrifugal force support. As a result, it is possible to obtain a rotor hub structure which is simple and has a small number of parts and is lightweight and highly reliable as a structure having high strength and low waste.
[0013]
  In particular, the plurality of arm portions of the centrifugal force support are formed in a substantially U shape that opens radially inward in a plane perpendicular to the rotor rotation axis, and are arranged radially. Moreover, the centrifugal force support is made of a composite material including a fiber reinforcement, and at least a part of the fiber reinforcement extends over the plurality of arm portions and is arranged in a loop shape. Since such a fiber reinforcement is included, the centrifugal force transmitted from the rotor blade to the arm portion is efficiently transmitted to the other arm portion without being transmitted to the mast structure, and the centrifugal force applied to the rotor hub structure is A plurality of arm portions are integrally formed so as to form a closed loop, so that the centrifugal force support in a loop shape can be canceled out with high efficiency. Therefore, by making the centrifugal force support a highly efficient structure with respect to the centrifugal force load, the size and weight can be made as small as possible, and the strength reliability can be increased. In addition, since each arm portion is formed in a U-shape in a plane perpendicular to the rotor rotation axis, the centrifugal force support, which is a strength member, is disposed near the rotor rotation surface, and near the rotor rotation surface. It is easy to secure a mounting position of a damper to be disposed, specifically, a damper for damping the dragging motion of the rotor blade.
  Further, by arranging the first blade supporting bearing means in the vicinity of the rotor mast and on the inner side of the rotor mast, the shear force applied from the rotor blade can be directly transmitted from the first blade supporting bearing means to the rotor mast. As a result, the rotor mast mainly supports the shearing force, and the centrifugal force support can separate the load path as a structure that mainly supports the centrifugal force, thereby realizing a highly efficient rotor hub structure. . Therefore, the strength and reliability of the rotor hub structure can be improved, and the weight of the rotor hub structure can be reduced.
[0014]
The present invention according to claim 2 is characterized in that each arm portion has a substantially U-shape that is smoothly curved.
[0015]
According to the present invention, each arm portion is formed in a substantially U-shape that is smoothly curved, such as a semicircular shape, a semi-elliptical shape, and a parabolic shape, for example, so that an excessively large stress is locally generated in each arm portion. This can be prevented. In this way, the centrifugal force support can be optimized to a shape that is more efficient in terms of strength and further reduced in weight.
[0018]
  Claim3The present invention described is provided at a position different from the first blade supporting bearing means, and each rotor blade is angularly displaceable about the same angular displacement center as the angular displacement center of the first blade supporting bearing means. , And further includes second blade support bearing means for transmitting shearing forces in the rotor rotational axis direction and circumferential direction applied from each rotor blade to the mast.
[0019]
According to the present invention, the second blade supporting bearing means supports each rotor blade so as to be angularly displaceable about the same angular displacement center as the angular displacement center of the first blade supporting bearing means, and also rotates the rotor. Axial and circumferential shear forces can be transmitted to the mast by this second blade support bearing means. In this way, the centrifugal force support body can have a highly efficient structure as a structure that mainly supports the centrifugal force. Further, the shear force can be transmitted to the mast by the first blade support bearing means, and the shear force can be transmitted to a plurality of transmission paths. The structure can be obtained, and the reliability can be further improved.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
  FIG. 1 is a cross-sectional view showing a rotor hub structure 20 of a rotary wing aircraft according to an embodiment of the present invention, partially cut along a plane orthogonal to a rotor rotation axis L1. FIG. 2 is a cross-sectional view showing the rotor hub structure 20 partially cut along a plane including the rotor rotation axis L1. Rotor hub structure (hereinafter sometimes referred to as “hub”)20Is suitably used, for example, for medium-sized and large-sized rotorcraft.
[0021]
The hub 20 basically includes a support structure 22 and a rotor mast (hereinafter also referred to as “mast”) 23, and is rotatably provided around a predetermined rotor rotation axis L1. A plurality of, in the present embodiment, four rotor blades (hereinafter also referred to as “blades”) 24 are connected to the support structure 22, and the mast 23 is a rotational force from a prime mover mounted on a rotary wing aircraft. It is fixed to the conduction shaft that guides. The hub 20 transmits the rotational force transmitted through the conduction shaft to each blade 24, and rotates each blade 24 around a rotor rotation axis (hereinafter, also referred to as “rotation axis”) L1.
[0022]
The hub 20 is provided in the rotary wing aircraft with one axial direction A1 along the rotor rotational axis L1 being upward and the other axial direction A2 being downward. In the following description, one axial direction A1 may be referred to as “upward” and the other axial direction A2 may be referred to as “downward”. In the following description, “plan view” means “view in the axial direction”.
[0023]
A frustum-like mast 23, which is hollow and substantially cylindrical and expands toward the top, is provided at the upper end of the rotor body of the rotary wing aircraft so as to be rotatable around the rotor rotation axis L1. A loop body 35 constituting a part of the support structure 22 for supporting the four blades 24 is provided at the upper end portion of the mast 23. The mast 23 and the loop body 35 may be integrally formed, or may be riveted after being formed separately, but are finally formed integrally. The mast 23 and the loop body 35 are composite materials including a fiber reinforced material, specifically, at least unidirectional material fibers as a fiber reinforced material, that is, fiber materials that are continuously connected to form a linear body, and are synthesized in advance. It is formed using a fiber material impregnated with resin. In the present embodiment, such a fiber material is used for integral molding. In FIG. 1, in order to facilitate understanding of the structure, the mast 23 and the loop body 35 are shown by different hatching.
[0024]
The four blades 24 are arranged, that is, arranged at regular intervals in the circumferential direction. A substantially U-shaped yoke 27 that opens toward the radially outer side Rs in a plane including the rotation axis L1 is provided at the end portion of each blade 24 in the radially inner direction Rk. Each yoke 27 is configured by connecting the ends of the two upper and lower plates 28 and 29 in the radially inward direction Rk by a connecting body 30.
[0025]
The yoke 27 is connected to the blade 24 at the ends of the plates 28 and 29 in the radially outward direction Rs. By providing the yoke 27 on each blade 24 in this manner, an annular connecting portion 33 configured by the blade 24 and the yoke 27 cooperating is provided. The connecting portion 33, particularly the yoke 27, is connected to the loop body 35, and each blade 24 is supported by the loop body 35.
[0026]
FIG. 3 is a plan view showing the loop body 35. FIG. 4 is a plan view showing the main part of the loop body 35. The frame body 25 includes a loop body 35 that is a centrifugal force support body and a stiffener 36 that is a reinforcing coupling body. The loop body 35 and the stiffener 36 are integrally formed of the composite material described above.
[0027]
The loop body 35, which can also be called a looped tension element, has arm portions 37 arranged to extend in the radial direction at regular intervals in the circumferential direction. The number of the arm portions 37 is the same as the number of blades 24, and they are connected together. Then, it is formed in a radial shape in plan view, specifically, a substantially cross shape. The loop body 35 is arranged so that the cross is along the longitudinal direction of the four blades 24, that is, the arm portions 37 of the loop body 35 are spaced from each blade 24 in the circumferential direction in plan view. Has been.
[0028]
Each arm portion 37 is curved in a plane orthogonal to the rotor rotation axis L1 and is formed in a substantially U shape that opens toward the radially inner Rk, and is integrated with each other at the end of the radially inner Rk. It is lined up. More specifically, each arm portion 37 is connected to the arm portion 37 disposed on the opposite side of the axis L1 at a position where the inner end is shifted by 180 degrees around the axis. ing. In this way, the two arm portions 37 disposed on the opposite sides with respect to the axis L1 are connected so as to form a substantially elliptic closed loop in cooperation with each other, and are displaced by 90 degrees from each other. Two closed loops are combined to form a substantially cross-shaped loop body 35.
[0029]
FIG. 5 is a plan view showing the fiber loop 80. FIG. 6 is an exploded perspective view showing the loop body 35. FIG. 7 is a cross-sectional view seen from the section line S7-S7 in FIG. FIG. 8 is a cross-sectional view seen from the section line S8-S8 of FIG. The loop body 35 is formed by arranging a fiber material such as a unidirectional material fiber previously impregnated with a synthetic resin so as to conform to the two substantially elliptical shapes to form a fiber loop 80 having a uniform thickness. The fiber loops 80 are coaxially arranged and alternately shifted by 90 degrees and stacked.
[0030]
More specifically, when the plurality of fiber loops 80 are laminated as described above, four overlap portions 81 where the fiber loops 80 overlap each other are formed. If only the fiber loops 80 are stacked, four spaces having a shape in which the fiber loops 80 are divided by the overlap portions 81 are formed between the fiber loops 80 arranged in the same direction every other layer. Pad materials 82 and 83 are provided so as to fill these spaces. Accordingly, in one layer, four pad materials including the fiber loop 80, the two linear pad materials 82, and the two substantially U-shaped pad materials 83 extend along the fiber loop 80 of the adjacent layer. Provided.
[0031]
The pad members 82 and 83 have the same structure as that obtained by dividing the fiber loop 80 into four parts by removing portions corresponding to the four overlap portions 81 from the fiber loop 80. That is, the same composite material is formed in the same shape as the corresponding part.
[0032]
In this way, the fiber loop 80 and the pad members 82 and 83 are laminated, for example, several tens of layers, and a total of 5 in the center central hole and four connection holes arranged every 90 degrees around the center central hole. A loop body 35 having a hole inserted in one axial direction is formed. Thus, the loop body 35 which occupies about 50% of the fiber material contained in the continuous loop-shaped fiber material can be formed. The continuous loop-shaped fiber material in the present embodiment is a fiber material of the fiber loop 80.
[0033]
In the present embodiment, about 50% of the loop-shaped fiber material is included, and the centrifugal force from the rotor blade 24 is easily offset. As a result, in order to resist centrifugal force, a highly efficient structure can be realized. Therefore, it is possible to realize the loop body 35 that can obtain a small size and a high strength. If at least a part of the fiber material is a loop-like fiber material, the loop-like fiber material can efficiently cancel the centrifugal force. Therefore, 50% or more of the fiber material is not necessarily in the loop shape. It is not necessary to be present, and it may be less than this. However, in order to obtain as high a strength as possible, it is preferably contained at least about 50%. Of course, it may contain more than 50%. In FIGS. 7 and 8, the hatching is changed for each layer for easy understanding, but in actuality, they are integrally formed.
[0034]
Each arm portion 37 has a shape that is smoothly curved when cut by a plane perpendicular to the rotor rotation axis L1. Specifically, this shape may be a substantially semicircular shape (including a semicircular shape), a substantially semielliptical shape (a semielliptical shape), and a substantially parabolic shape (including a parabolic shape). It is a substantially semi-elliptical shape. Further, in the present embodiment, the end portion of the radially outward Rs corresponding to the U-shaped bottom portion of each arm portion 37 is planar, and the center position of the end portion of the arm portion is perpendicular to the plane. A straight line passing therethrough is formed so as to be orthogonal to the axis L1.
[0035]
The number of the stiffeners 36 corresponding to the number of the arm portions 37, and thus the four stiffeners 36, is provided between the two arm portions 37 adjacent to each other in the circumferential direction. Each stiffener 36 has a substantially isosceles triangular shape in a plan view, two equal sides are along each arm portion 37, and the other side extends between the ends of the radially outward Rs of each arm portion 37. It is arranged to extend. The loop body 35 and each stiffener 36 are integrally formed to form a substantially octagonal frame body 25.
[0036]
Such a frame body 25 is coaxially fitted to the upper end portion 47 of the mast 23 formed in a substantially cylindrical shape, and is integrally formed in a state where it is connected to the mast 23 at the outer peripheral portion thereof. The stiffener 36 contributes to the connection between the frame body 25 and the mast 23 and contributes to the reinforcement between the loop body 35 and the mast 23. In the vicinity of the upper end 47 at the position where the arm portion 37 is arranged in the circumferential direction of the mast 23, a through hole 50 penetrating in the radial direction except for the upper end is formed. The blades 24 are connected to the loop body 35 in a state where the arm portions 37 and the yokes 27 are inserted and fitted to each other.
[0037]
  A bottom portion located at the center between both ends of the U-shape of each arm portion 37, and thus an end portion of each arm portion 37 on the radially outward Rs side, and a U-shape in the yoke 27 that radially faces this end portion. An elastomeric bearing 45 serving as a first blade supporting bearing means having an elastomeric shape is provided between the bottom portion located at the center portion between the two end portions of the elastomer. Each blade is radially directed to the support structure 22 via an elastomeric bearing 45.OutsideRsInIt is supported.
[0038]
The bottom 40 which is the end of each arm portion 37 on the radially outward Rs side is connected to the bottom inner surface portion which is the surface portion on the radially inward Rk side which is the inside of each arm portion 37. Is provided. The load transmitting member 41 has a surface facing the bottom of each arm portion 37 in a state of surface contact with the inner surface of the bottom of the arm portion 37.
[0039]
An elastomeric bearing 45 is provided on the radially inner surface of each load transmitting member 41. The elastomeric bearing 45 as the first blade supporting bearing means is a spherical elastomeric bearing, and has a structure in which a plurality of metal shims (thin plates) and a plurality of rubber layers (elastic layers) are laminated, that is, a plurality of elastomeric bearings. In this structure, a rigid body and a plurality of elastic bodies are laminated. Each metal shim and each rubber layer have a partial spherical shape that is a part of a sphere, and are formed in a partial spherical shape centered on one common reference point.
[0040]
The elastomeric bearing 45 can be supported against the compressive force in the stacking direction of each metal shim and each rubber layer, and the reference point which is the center of the sphere by the elastic deformation of the rubber layer is the center of angular displacement. The angular displacement around the center can be allowed. The angular displacement direction is a direction around three orthogonal axes passing through the angular displacement center. The elastomeric bearing 45 is disposed in the vicinity of the virtual cylindrical surface where the mast 23 is disposed and on the inner side in the radial direction from the virtual cylindrical surface. More specifically, the virtual cylindrical surface is a cylindrical surface along the outer peripheral surface of the mast 23 and is included in the thickness of the mast 23. The virtual cylindrical surface is substantially cylindrical and expands as it goes upward. It has a frustum shape.
[0041]
The elastomeric bearing 45 is disposed in the upper end portion 47 of the mast 23 in which the stacking direction thereof coincides with the radial direction of the hub 20 and the angular displacement center is located radially outwardly Rs of the arm portion 37. It is connected to the transmission member 41. The end of the elastomeric bearing 45 opposite to the side connected to the load transmitting member 41 is connected to the connecting portion 30 of the yoke 27. In this way, the load transmitting member 41 provided on the bottom portion 40 of the arm portion 37 and the connecting portion 30 opposed to the load transmitting member 41 from the radially inward Rk side are interposed between them. Connected by 45.
[0042]
Further, a fitting hole 51 penetrating in the radial direction is formed in the upper end portion 47 at a position where the arm portion 37 is arranged with respect to the circumferential direction of the mast 23, and the second blade support bearing means is formed in the fitting hole 51. A spherical bearing 53 is held in place. Thus, the spherical bearing 53 is disposed so as to include the virtual cylindrical surface. More specifically, the angular displacement center is disposed on the virtual cylindrical surface. The spherical bearing 53 has an outer ring held by the mast 23 and an inner ring supported to be angularly displaceable with respect to the outer ring. The angular displacement direction of the inner ring with respect to the outer ring is a direction around three orthogonal axes passing through the same angular displacement center as the angular displacement center of the elastomeric bearing 45.
[0043]
An auxiliary yoke 55 is provided between the plates 28 and 29 of the yoke 27 at a position on the radially outer side Rs of the mast 23. The auxiliary yoke 55 extends in the longitudinal direction of the blade 24 and has a radius. A fitting shaft 56 protruding inward in the direction Rk is formed. The fitting shaft 56 is inserted into and supported by the inner ring of the spherical bearing 53 so as to be displaceable along the axis of the fitting shaft 56.
[0044]
The support structure 22 includes the frame body 25, the load transmission member 41, the elastomeric bearing 45, and the spherical bearing 53. With the configuration including the elastomeric bearing 45 and the spherical bearing 53, each blade 24 is allowed to be slightly displaced in the radial direction and orthogonal so that flapping, dragging, and feathering can be performed around the angular displacement center. It is connected to and supported by the support structure 22 so that it can be angularly displaced about three axes. Flapping is an angular displacement around the axis perpendicular to the longitudinal direction of the blade 24 and the axis L1, dragging is an angular displacement around an axis parallel to the axis L1, and feathering is in the longitudinal direction of the blade 24. Angular displacement around a parallel axis.
[0045]
In such a hub 20, the centrifugal force acting on the blade 24 when the blade 24 connected to the support structure 22 is rotationally driven around the axis L 1 is transmitted via the yoke 27, the elastomeric bearing 45 and the load transmission member 41. Is transmitted to the bottom portion 40 of the arm portion 37 of the loop body 25. In the loop body 35, the applied centrifugal force is canceled in the loop body 35 by the structure as described above, and the blade 24 is supported against the centrifugal force so as not to act on the mast 23 or the like. In the hub 20, when the blade 24 flapping and dragging, the shearing force acting on the blade 24 in the direction along the axis L 1 and in the circumferential direction is transmitted from the spherical bearing 53 to the mast 23 and does not act on the loop body 35. In this manner, the blade 24 is supported by the mast 23 by using a shearing force.
[0046]
In order to change the pitch angle by feathering each blade 24 supported in this manner, a blade operation means 60 is provided outside the mast. The blade operating means 60 is provided for each blade, and has an annular swash plate 61 that surrounds the lower portion of the mast 23 and is rotatably supported around the axis L1. A lower end portion is common to the swash plate 61. And a pitch link 62 connected to be angularly displaceable. The auxiliary yoke 55 is formed with a connecting arm 63 protruding in one circumferential direction, and the upper end portion of the pitch link 62 is connected to the connecting arm 63 so as to be angularly displaceable. Using this blade operation means 60, each swash plate 61 can be feathered by driving the swash plate 61 along the axis L1 and by displacing the swash plate 61 around the axis perpendicular to the axis L1. .
[0047]
A damper 65 is provided corresponding to each blade 24. The damper 65 has a structure in which one end portion is connected to the upper end portion 47 of the mast 23 and the other end portion is connected to the auxiliary yoke 55 so as to absorb the dragging energy by resisting displacement between the both end portions. is there. Thus, the damper 65 is disposed along the rotational surface of the blade 24, in other words, substantially along the dragging displacement direction of the blade 24, and is configured to efficiently absorb energy.
[0048]
  In the present embodiment, the loop body 35 is configured to loop in a plane orthogonal to the axis L1, so that the arm portion 37 and the arm portion 37 are located at the same position in the direction of the axis L1.37It is possible to easily secure in the mast 23 a portion having a high strength against an external force in the circumferential direction, and a damper 65 can be provided on the mast 23. That is, it is not necessary to provide a member for attaching the damper 65 separately.
[0049]
Further, a droop stop mechanism 70 is provided for each blade 24 in order to prevent the blade 24 from dripping when the rotation is stopped. The droop stop mechanism 70 includes an operation member 72 supported at an intermediate position by a support shaft 71 around an axis substantially perpendicular to the longitudinal direction of the blade 24, a heavy cone 73 provided on one side with respect to the support position of the operation member 72, Spring means 75 for applying a spring force in a direction for displacing the heavy cone 73 radially inward Rk. The droop stop mechanism 70 is disposed at a position facing the yoke 27 from the radially inner side Rk.
[0050]
In this droop stop mechanism 70, when the rotation of the blade 24 is stopped, the locking portion 77, which is the portion opposite to the side where the heavy cone 73 of the operating member 72 is provided by the spring force of the spring means 75, is directed radially outward Rs. The locking projection 74 formed in the radially inward direction Rk on the connecting portion 30 of the yoke 27 can be locked from the upper side while being arranged at the protruding locking position and in the locked position. Locking in this way prevents the blade 24 from dripping. When the blade 24 rotates, the operating member 72 is angularly displaced so that the locking portion 77 is displaced radially inward Rk by the centrifugal force acting on the heavy cone 73, and is in the retracted position. Thus, the locking projection 74 is unlocked.
[0051]
Such a hub 20 has a fairing 21 connected to a mast 23. The fairing 21 covers the support structure 22, the blade operating means 60, the damper 65, and the like, and is configured to prevent damage due to external factors.
[0052]
According to the rotor hub structure 20 of the rotary wing aircraft described above, the loop body 35 is integrally formed of a composite material, and an elastomeric bearing 45 is attached to the arm portion 37 of the loop body 35 via the load transmission member 41. The blade 24 is supported from the radially outward side by the elastomeric bearing 45 provided. In this way, the arm portion 37 supports the elastomeric bearing 45 via the load transmitting member 41, and the loop body 35 is brought into contact with the surface by a surface contact without using a member such as a fastening part such as a bolt that exerts a bending force other than a compressive load. Centrifugal force can be transmitted to Thus, it is possible to provide a structure that can support the centrifugal force only by the main constituent members, thereby simplifying the structure, reducing the number of parts, and reducing the weight and improving the reliability.
[0053]
In particular, the plurality of arm portions 37 of the loop body 35 are formed in a U-shaped loop shape opening radially inward in a plane orthogonal to the rotor rotation axis L1, and are arranged radially. The centrifugal force applied to the rotor hub structure can be canceled with high efficiency in the centrifugal force support. Therefore, by making the centrifugal force support a highly efficient structure with respect to the centrifugal force load, the size and weight can be made as small as possible, and the strength reliability can be increased.
[0054]
Further, by making each arm portion 37 into a U-shape that smoothly curves, such as a semicircular shape, a semi-elliptical shape, and a parabolic shape, it is possible to prevent excessive stress from being locally generated in each arm portion 37. Can do. By optimizing the shape in this way, the loop body 35 can be further reduced in weight.
[0055]
Further, the shearing force in the rotor rotational axis direction and the circumferential direction can be transmitted to the mast 23 by another spherical bearing 53 different from the elastomeric bearing 45. In this way, the loop body 35 can have a highly efficient structure as a structure mainly supporting the centrifugal force. Further, the shear force can be transmitted to the mast by the elastomeric bearing 45, and it is also possible to adopt a structure in which the shear force is transmitted to a plurality of transmission paths. And reliability can be further improved. Further, since the center of angular displacement of the spherical bearing 53 is disposed within the thickness of the mast 23, the bending force can be prevented from acting on the mast 23 by the shearing force, and the shearing force can be transmitted to the mast 23.
[0056]
Further, by arranging the elastomeric bearing 45 in the vicinity of the mast 23 and on the inner side of the mast 23, the shearing force applied from the blade 24 can be transmitted directly from the elastomeric bearing 45 to the mast 23. As a result, the mast 23 mainly supports the shearing force, and the loop body 35 can separate the load path as a structure mainly supporting the centrifugal force, so that the hub 11 having high strength can be realized. Therefore, the strength and reliability of the hub 11 can be improved, and the weight of the hub 11 can be reduced.
[0057]
Since the loop body 35 forms the frame body 25 integrally with the stiffener 36 and is formed integrally with the mast 23, the structure can be further simplified. Thus, when integrating the frame body 25 and the mast 23, since the frame body 25 is formed in a substantially octagonal shape in a plane orthogonal to the rotor rotation axis L1, the frame body 25 is fitted into the mast 23. And can be easily formed integrally with the composite material.
[0058]
FIG. 9 is a perspective view showing a part of a loop body 35A according to another embodiment of the present invention. FIG. 10 is a cross-sectional view seen from the section line S10-S10 in FIG. The same parts as those in the above embodiment are given the same reference numerals, and detailed description thereof will be omitted. Although the fiber loop 80 of the embodiment of FIGS. 1 to 8 is formed to have a uniform thickness, in the present embodiment, the fiber loop 80A has an overlap portion 89 corresponding to the overlap portion 81 and the remaining portion. The thickness is smaller and the width dimension is larger than the portion 88.
[0059]
In the present embodiment, the remaining portion 88 is formed in a tapered shape so that the thickness gradually decreases and the width dimension increases as the overlapping portion 89 is approached, and the remaining portion 88 is formed in a tapered shape. Except for the portion to be formed, the thickness is uniform, and the thickness is twice the thickness of the overlapping portion 89. The fiber loop 80A is made of the same composite material as the fiber loop 80 of the above embodiment.
[0060]
  When only the fiber loops 80A formed in this way are stacked, no gap is formed between the fiber loops 80A in the overlapping portion 89 and the portion having a uniform thickness in the remaining portion 88, but the remaining portion 88 is tapered. A gap is formed between the portions. A tapered pad material 90 having the same shape as this gap is provided so as to fill this gap. The pad material 90 isFiber loopIt is formed of a composite material similar to 80A.
[0061]
With such a configuration, among the fiber materials included in the loop body 35A, the content of the loop-shaped fiber material becomes high, for example, exceeding 90%. Therefore, it can be set as the structure where the intensity | strength efficiency with respect to a centrifugal force is more efficient. In FIG. 10, hatching is changed for each layer for easy understanding, but in actuality, the layers are integrally formed.
[0062]
  FIG. 11 is a plan view showing a hub 20D according to still another embodiment of the present invention. FIG. 12 is a plan view showing the frame body 25D of the hub 20D. FIG. 13 shows a loop of the frame body 25DbodyIt is a top view which shows 35D. The same parts as those in the above embodiment are given the same reference numerals, and detailed description thereof will be omitted. Although the hub 20 in FIGS. 1 to 10 is configured to support four blades 24, the hub 20 </ b> D of the present embodiment has a structure that supports five blades 24.
[0063]
The difference is that the shape of the frame body 25D is different. In the frame body 25D, five arm portions 37 are provided on the loop body 35D. Each of the arm portions 37 of the loop body 35D is composed of two arm portions 37 in which one end portion in the circumferential direction of two end portions on the radially inward side is disposed on the opposite side across the axis L1. A fiber reinforced material such as a unidirectional material fiber impregnated with a synthetic resin in advance is looped so as to be drawn in a single stroke so as to extend to the end portion on the other circumferential side of the arm portion 37 arranged on the one side in the main direction. A fiber loop 80D is disposed and formed. Even with such a hub 20D, the same effect can be obtained.
[0064]
  FIG. 14 is a plan view showing a frame body 25E of a hub 20E according to still another embodiment of the present invention. FIG. 15 shows a loop of the frame body 25E.bodyIt is a top view which shows 35E. The same parts as those in the above embodiment are given the same reference numerals, and detailed description thereof will be omitted. The hub 20E of the present embodiment has a structure that supports five blades 24.
[0065]
A difference from the hub 20D of FIGS. 11 to 13 is that the arrangement of the fiber reinforced material of the frame body 25E is different. In the loop body 35E of the frame body 25E, both end portions of each arm portion 37 are connected to both end portions of the two arm portions 37 disposed on the opposite side across the axis L1, thereby forming a substantially elliptic closed loop. As described above, the fiber loops 80E on which fiber reinforcing materials such as unidirectional fibers pre-impregnated with a synthetic resin are disposed are sequentially laminated while being shifted in the circumferential direction. Even with such a hub 20E, the same effect can be obtained.
[0066]
The loop body is not limited to the configuration of the above example, and the shape may be changed according to the number of blades. That is, the arm portions are disposed so as to wrap in the plan view with respect to the longitudinal direction of the rotor blade, and each arm portion is formed in a shape that loops substantially along a virtual plane perpendicular (orthogonal) to the rotor rotation axis L1. That's fine. As described with reference to FIGS. 6 to 10, since the fiber loops overlap in the thickness direction, each fiber loop can be formed in a loop shape by being slightly offset from the corresponding virtual plane. .
[0067]
As another embodiment of the present invention, the rotor hub structure of the present invention can be applied to a small and medium-sized rotorcraft. The number of rotor blades is not limited to four and five. In addition, various partial configurations can be changed without departing from the present invention.
[0068]
【The invention's effect】
According to the present invention, in the rotor hub structure in which a plurality of rotor blades are connected, the centrifugal force support body is formed integrally with a plurality of arms by the composite material. Each arm part is provided with a first blade supporting bearing means of an elastomeric type. The yoke provided on the rotor blade is supported from the radially outer side by the first blade supporting bearing means. With this configuration, the centrifugal force acting on the rotor blade can be transmitted to the integral centrifugal force support. As a result, it is possible to obtain a rotor hub structure which is simple and has a small number of parts and is lightweight and highly reliable as a structure having high strength and low waste.
[0069]
  In particular, the plurality of arm portions of the centrifugal force support are formed in a substantially U shape that opens radially inward in a plane perpendicular to the rotor rotation axis, and are arranged radially. Moreover, the centrifugal force support is made of a composite material including a fiber reinforcement, and at least a part of the fiber reinforcement extends over the plurality of arm portions and is arranged in a loop shape. Since such a fiber reinforcement is included, the centrifugal force transmitted from the rotor blade to the arm portion is efficiently transmitted to the other arm portion without being transmitted to the mast structure, and the centrifugal force applied to the rotor hub structure is A plurality of arm portions are integrally formed so as to form a closed loop, so that the centrifugal force support in a loop shape can be canceled out with high efficiency. Therefore, by making the centrifugal force support a highly efficient structure with respect to the centrifugal force load, the size and weight can be made as small as possible, and the strength reliability can be increased. In addition, since each arm portion is formed in a U-shape in a plane perpendicular to the rotor rotation axis, the centrifugal force support, which is a strength member, is disposed near the rotor rotation surface, and near the rotor rotation surface. It is easy to secure a mounting position of a damper to be disposed, specifically, a damper for damping the dragging motion of the rotor blade.
  Further, by arranging the first blade supporting bearing means in the vicinity of the rotor mast and on the inner side of the rotor mast, the shear force applied from the rotor blade can be directly transmitted from the first blade supporting bearing means to the rotor mast. As a result, the rotor mast mainly supports the shearing force, and the centrifugal force support can separate the load path as a structure that mainly supports the centrifugal force, thereby realizing a highly efficient rotor hub structure. . Therefore, the strength and reliability of the rotor hub structure can be improved, and the weight of the rotor hub structure can be reduced.
[0070]
Further, according to the present invention, each arm portion is formed in a substantially U-shape that smoothly curves, such as a semicircular shape, a semi-elliptical shape, and a parabolic shape, so that excessively high stress is locally applied to each arm portion. It can be prevented from occurring. In this way, the centrifugal force support can be optimized to a shape that is more efficient in terms of strength and further reduced in weight.
[0072]
According to the invention, the second blade supporting bearing means supports each rotor blade so as to be angularly displaceable around the same angular displacement center as the angular displacement center of the first blade supporting bearing means. The shear force in the rotational axis direction and the circumferential direction can be transmitted to the mast by the second blade supporting bearing means. In this way, the centrifugal force support body can have a highly efficient structure as a structure that mainly supports the centrifugal force. Further, the shear force can be transmitted to the mast by the first blade support bearing means, and the shear force can be transmitted to a plurality of transmission paths. The structure can be obtained, and the reliability can be further improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a rotor hub structure 20 of a rotary wing aircraft according to an embodiment of the present invention, partially cut along a plane orthogonal to a rotor rotation axis L1.
FIG. 2 is a cross-sectional view showing a rotor hub structure 20 partially cut along a plane including a rotor rotation axis L1.
3 is a plan view showing a loop body 35. FIG.
4 is a plan view showing a main part of the loop body 35. FIG.
5 is a plan view showing a fiber loop 80. FIG.
6 is an exploded perspective view showing a loop body 35. FIG.
7 is a cross-sectional view taken along section line S7-S7 in FIG.
FIG. 8 is a cross-sectional view taken along section line S8-S8 in FIG.
FIG. 9 is a perspective view showing a part of a loop body 35A according to another embodiment of the present invention.
10 is a cross-sectional view seen from a section line S10-S10 in FIG.
FIG. 11 is a plan view showing a hub 20D according to still another embodiment of the present invention.
FIG. 12 is a plan view showing a frame body 25D of the hub 20D.
FIG. 13: Loop of frame body 25DbodyIt is a top view which shows 35D.
FIG. 14 is a plan view showing a frame body 25E of a hub 20E according to still another embodiment of the present invention.
FIG. 15 shows a loop of the frame body 25E.bodyIt is a top view which shows 35E.
FIG. 16 is a cross-sectional view showing a conventional rotor hub structure 1 using an elastomeric bearing.
FIG. 17 is a cross-sectional view showing another conventional rotor hub structure 10 using an elastomeric bearing.
[Explanation of symbols]
  20, 20A, 20D, 20E Rotor hub structure
  22 Support structure
  23 Mast
  24 Rotor blade
  25, 25D, 25E frame body
  27 York
  35, 35A, 35D, 35E Loop body
  37 Arm
  41 Load transmission member
  45 Elastomeric bearing
  53 Spherical bearing
  80, 80A, 80D, 80E fiber loop

Claims (3)

A rotor hub structure in which a plurality of rotor blades are connected,
In a plane orthogonal to the rotor rotation axis, each of the plurality of arm portions is formed in a substantially U shape that opens radially inward, and is arranged radially when viewed in the rotation axis direction of the rotor. By the composite material including the fiber reinforcement material, the arm portions are provided so as to be continuous at the radially inner end, and at least some of the fiber reinforcement materials extend over the plurality of arm portions and are arranged in a loop shape. A centrifugal force support that forms a loop by integrally forming the arm portion of the
A first blade supporting bearing means provided on the radially inner side of each arm portion and supported by each arm portion, and a yoke provided on the radially inner end portion of the rotor blade as a flap, a lead lug , supported from the radially inward side in a state that allows the angular displacement of the feathering direction, a first blade support bearing means elastomeric shaped formed by laminating an elastic member and a rigid body,
A cylindrical rotor mast to which rotational force is transmitted from the prime mover,
A rotor hub structure for a rotary wing aircraft, characterized in that the first blade support bearing means is disposed in the vicinity of the virtual cylindrical surface where the rotor mast is disposed and inward of the virtual cylindrical surface.   2. The rotor hub structure for a rotary wing aircraft according to claim 1, wherein each arm portion has a substantially U shape that is smoothly curved. 3.   The rotor blades are supported so as to be angularly displaceable around the same angular displacement center as the angular displacement center of the first blade support bearing means, and the shearing force in the rotor rotational axis direction and circumferential direction applied from each rotor blade is transmitted to the mast. 3. The rotor hub structure for a rotary wing aircraft according to claim 1, further comprising second blade supporting bearing means for performing the operation.

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