JPH10287297A - Flex beam for helicopter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the increase in shearing force and bending rigidity of an adhesive surface by bending and forming a feather ring and a lead lug part, and forming a central part by a one-way member making contact with the lower surface of a central member and fabric composite materials arranged in the corner of the bent parts in the front and rear ends of each one-way member. SOLUTION: A central member 10, an upper member and a lower member are molded by use of a prepreg of fabric composite material, and one-way members 11, 14 are molded by use of a prepreg of one-way composite material. A lower frame 20 is set, and the lower member 15, a laminated material 16 consisting of a prepreg of fabric composite material, the one-way member 14, and the central member 10 are arranged in order thereon, and side frames 21, 21 are set on both sides of the lower frame 20. The laminated material 16 is arranged in a position corresponding to a bent part 20a. Then, the one-way member 11, the upper member 12, and a laminated material 13 are placed in order on the side frames 21, 21, and an upper frame 22 is set thereon. The laminated material 13 is arranged in a position corresponding to a bent part 22a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flex beam for a helicopter having a bearingless type hub structure for supporting a rotor of a helicopter.

[0002]

2. Description of the Related Art A flex beam for a helicopter having a bearingless hub structure for supporting a rotor blade of a helicopter requires a flapping flexible structure and an elastic structure for performing feathering and lead-lag motion.

[0003] In this type of helicopter flex beam, a plurality of parallel reinforcing ribs extending in the blade length direction at predetermined in-plane intervals are formed in an integral frame, and a plurality of thin plate ribs are formed. Flex beam elastic body structure that is easy to twist and has low lead lug rigidity
For example, it is described in JP-A-59-57098.

However, in the above-mentioned type of flex beam for a helicopter, at present, problems remain in terms of weight reduction and manufacturing of the flex beam elastic body structure.

[0005] In order to solve the above-mentioned problems, an elastic structure portion for performing feathering and lead lug motion is formed of a unidirectional composite loop material on both sides of a central member of a composite plate-shaped central member. The applicant has developed a helicopter flex beam configured by arranging a pair of frame members (see Japanese Patent Application Laid-Open No. 1-178100).

[0006]

In the above-mentioned flex beam for a helicopter, since the torsion flexible portion is formed of a one-way composite loop material, the tensile strength in the direction orthogonal to the longitudinal direction is low, and the torsion load is reduced. There is a weak point in strength, and the flapping flexible structure also has a unidirectional composite material which is simply disposed adjacent to and bonded to both sides of the laminate. The interlaminar shear strength is a weak point, leaving a problem that the fiber strength of the unidirectional composite material is not sufficiently utilized.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and suppresses an increase in the shearing force and bending stiffness of a bonding surface of a mast attachment and flapping portion, and reduces a fiber and a unidirectional member of a feathering and a lead lug portion. It is an object of the present invention to provide a helicopter flex beam that significantly reduces the force applied in the orthogonal direction.

[0008]

SUMMARY OF THE INVENTION A helicopter flex beam of the present invention has an integrally formed mast mounting and flapping portion and a feathering and lead lug portion, wherein the mast mounting and flapping portion is a woven composite material. A upper member made of a woven fabric composite material contacting at the center in the front-rear direction of the upper surface of the center member, a lower member made of a woven fabric composite material contacting the lower surface of the center member at the center in the front-rear direction, and an upper member And a one-way member made of a one-way composite material sandwiched between central members, and a one-way member made of a one-way composite material sandwiched between a lower member and a central member. The member and the front and rear ends in a direction perpendicular to the longitudinal direction are bent and formed so as to be parallel to the center, and the center is in contact with the upper surface of the center member The one-way member, the one-way member having a front end and a rear end in a direction perpendicular to the longitudinal direction thereof bent and formed so as to be parallel to the central portion, and the central portion being in contact with the lower surface of the central member; It is formed with a woven composite material arranged at the corners of the bent portions at the front and rear ends of the member, and suppresses the increase in the shearing force and bending rigidity of the bonding surface, and also increases the tensile stress generated at the corners caused by torsion. Material or a laminated material composed of unidirectional members arranged in a direction perpendicular to the one-way member. The fiber strength of the unidirectional member is sufficiently reduced by greatly reducing the force applied in the direction perpendicular to the fibers of the receiving one-way member. Make use of it.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a helicopter flex beam. The flex beam 1 for a helicopter has a mast attachment and flapping portion 2 which is a flapping flexible structure portion at a central flat boss portion, and an elastic body structure which extends on both sides of the flapping portion 2 and performs feathering and lead-lag motion. It comprises a feathering and lead lug portion 3 as a portion, and a rotor blade mounting portion 4 which is a flat boss portion at both ends.

At the center of the mast mounting and flapping portion 2 of the helicopter flex beam 1, a through hole 6 is formed at the center of the helicopter mast, passing through a rotor rotation center 5. Has a metal bush 7 embedded therein so as to communicate vertically.

[0011] The helicopter flex beam 1 comprises:
As shown in FIG. 2, a central member 10 made of a woven composite material
A one-way member 11 made of a one-way composite material formed by a filament winding device and joined to the upper surface of the central member 10; and an upper member 12 made of a woven composite material disposed at the center of the upper surface of the one-way member 11. A laminated member 13 made of a woven fabric composite material disposed on both sides of the upper surface of the one-way member 11 along the side edges;
A one-way member 14 having the same configuration as the one-way member 11 joined to the lower surface of the one-way member 11, a lower member 15 made of a woven fabric composite material disposed at the center of the lower surface of the one-way member 14, and a lower surface of the one-way member 11 And a laminated material 16 made of a woven fabric composite material arranged on both sides along the side edges. The laminates 13 and 16 may be one-way composites as long as the direction of the filaments intersects the direction of the filaments of the one-way members 11 and 14.

A method of forming the helicopter flex beam 1 will be described. First, as shown in FIG. 2, the central member 10, the upper member 12, and the lower member 15 are formed using a prepreg of a woven fabric composite material, and the one-way members 11, 14 are formed using a prepreg of a one-way composite material. .

Next, as shown in FIG. 6, a lower frame 20 is installed, and a lower member 15, a laminated material 16 made of a prepreg of a woven composite material, a one-way member 14, and a central member 1 are mounted on the lower frame 20.
0 in order, and then the side frames 21 and
1 is set. In this case, the laminated material 16 is the one-way member 14.
Is disposed at a position corresponding to the bent portion (corner R portion) 20a at the front and rear ends of the front end.

Next, the one-way member 11 is attached to the side frames 21, 21.
, The upper member 12 and the laminated material 13 in this order, and the upper frame 2
2 is installed. In this case, the laminated material 13 is the one-way member 11
Is disposed at a position corresponding to the bent portion (corner R portion) 22a at the front and rear ends of the front end.

Next, the entire frame in which the members are arranged is fixed, the entire frame is placed in a heat-curing apparatus, and heat-curing is performed at a predetermined temperature for a predetermined time.

The helicopter flex beam 1 thus formed has a vertically symmetrical cross section in a direction perpendicular to the longitudinal direction.

As shown in FIG. 3, the mast attachment and flapping portion 2 includes a central member 10 and an upper member 12 which is in contact with an upper surface of the central member 10 at a central portion in the front-rear direction.
Lower member 1 that contacts the lower surface of central member 10 at the center in the front-rear direction.
5, a one-way member 11 sandwiched between the upper member 12 and the center member 10, and a one-way member 14 sandwiched between the lower member 15 and the center member 10. By receiving most, the upper member 12 and the lower member 1
5 can suppress the shearing force of the bonding surface with the central member 10.

The above feathering and lead lug portion 3
As shown in FIG. 4, the central member 10 and the front end and the rear end in the direction orthogonal to the longitudinal direction are bent and formed so as to be parallel to the central portion, and the central portion contacts the upper surface of the central member 10. A one-way member 12, a one-way member 14 in which a front end and a rear end in a direction perpendicular to the longitudinal direction are bent and formed so as to be parallel to the central portion, and the central portion contacts the lower surface of the central member 10; The laminated members 13 and 16 are arranged at the corners of the bent portions at the front and rear ends of the directional member. The laminated members 13 and 16 receive most of the tensile stress generated by torsion and increasing at the corners. Direction member 1
Significantly reduce the force applied in the direction perpendicular to the 1,14 fibers.

As shown in FIG. 5, the connecting portion between the mast attachment and flapping portion 2 and the feathering and lead lug portion 3 is formed by adjusting the thickness of the upper member 12 and the lower member 15 to the front end in the direction orthogonal to the longitudinal direction. And gradually decreases at the rear end.

The helicopter flex beam 1 having the above-described structure receives a large part of the bending load by the upper member 12 and the lower member 15 in the flapping portion 2, so that the central member 10 between the upper member 12 and the lower member 15 is moved. By suppressing the shearing force of the bonding surface and arranging the one-way members 11 and 14 between the upper member 12 and the central member 10 and between the lower member 15 and the central member 10, that is, inside, thereby suppressing an increase in bending rigidity. By arranging the laminated materials 13 and 16 having high tensile strength at the corners of the feathering and lead lug portions 3,
The laminated materials 13 and 16 receive the tensile stress generated at the corners caused by the torsion, and the force applied to the one-way members 11 and 14 in the direction perpendicular to the fibers can be greatly reduced.

According to the experiment, the fatigue strength of the helicopter flex beam 1 having the above-mentioned structure is as follows.
Compared with the helicopter flex beam described in Japanese Patent Publication No. 0-150, it was 150 times or more, and it was confirmed that the fatigue life was improved.

[0022]

As described above, according to the present invention, it is possible to suppress an increase in the shearing force and bending stiffness of the bonding surface of the mast attachment and flapping portion, and at the same time, orthogonal to the fibers of the one-way member of the feathering and lead lug portions. The force applied in the direction of movement can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a flex beam for a helicopter according to the present invention.

FIG. 2 is an exploded perspective view of a helicopter flex beam according to the present invention.

FIG. 3 is an enlarged sectional view taken along line AA of FIG. 1;

FIG. 4 is an enlarged sectional view taken along the line BB of FIG. 1;

FIG. 5 is an enlarged sectional view taken along the line CC of FIG. 1;

FIG. 6 is a view showing a means for forming a flex beam for a helicopter according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flex beam for helicopter 2 Mast attachment and flapping part 3 Feathering and lead lug part 10 Central member 11 One-way member 12 Upper member 13 Laminated material 14 One-way member 15 Lower member 16 Laminated material

Claims (3)

[Claims] A mast mounting and flapping portion;
In a helicopter flex beam having a feathering and lead lug portion and a rotor blade mounting portion, the mast mounting and flapping portion includes:
A central member made of a woven composite material, and an upper member made of a woven composite material contacting the center of the upper surface of the central member in the front-rear direction,
A lower member made of a woven composite material in contact with the lower surface of the center member at the center in the front-rear direction, a one-way member made of a one-way composite material sandwiched between the upper member and the center member, and sandwiched between the lower member and the center member A one-way member made of a one-way composite material, wherein the feathering and the lead lug portion are such that the center member and the front end and the rear end in a direction orthogonal to the longitudinal direction thereof are parallel to the center portion. The one-way member which bends and forms the central portion in contact with the upper surface of the central member, and the front and rear ends in a direction orthogonal to the longitudinal direction are formed by bending and forming the central portion of the central member so as to be parallel to the central portion. A flex beam for a helicopter, comprising: the one-way members in contact with a lower surface; and a laminated material made of a composite material disposed at corners of bent portions at front and rear ends of each one-way member. 2. The helicopter flex beam according to claim 1, wherein a cross-sectional shape in a direction orthogonal to the longitudinal direction is vertically symmetric. 3. A flex beam for a helicopter according to claim 1, wherein the laminated material is a unidirectional material in a direction orthogonal to the woven composite material and the one-way member.