JPH06247391A - Shank portion structure of composite blade - Google Patents

Abstract

PURPOSE:To provide such a shank portion structure of a composite blade Which comprises a wing spar made of a composite material and coupled to a metallic member, that damage to the wing spar due to impact from foreign objects and deterioration of its strength are prevented. CONSTITUTION:The wing spar 1 of a blade, which is made of a composite material, is integrally secured using an adhesive to an uneven portion formed by gluing of a connecting bar 5 to a guide member 4 which has a groove 4a formed on its outer periphery, and a bearing lace 10 and a bearing ball 11 are mounted in a recessed portion at the root of the guide member 4 and are bearing-coupled to a hub 12 and coupled to a variable pitch mechanism via an eccentric pin 7 which comprises a roller bearing 8 mounted at the root end face portion of the guide member 4, and a wing-spar protecting sleeve 16 is bonded and integrated via an intermediate layer 15 to the exposed portion of the wing spar 1 made of composite material at a shank portion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in the shank portion of a composite material blade such as an aircraft propeller blade having a blade shell and a girder made of a composite material such as FRP. To a shank part structure of a composite material blade in which a sleeve made of another material is attached to the shank part of the composite material via an intermediate layer having a low elastic modulus to protect the composite material spars.

[0002]

Blades such as aircraft propeller blades, turbofan blades, helicopter blades, and general industrial rotary blades have a joint structure called a shank portion for connecting the blades to a hub and a variable pitch mechanism. is doing. When the blade is made of a composite material such as FRP, it is necessary to bond the composite material spars and the metal member in the shank portion.

For example, it is necessary to fix an eccentric pin for changing the pitch of the blade, a bevel gear, a worm gear, a ball screw, etc. to the blade. However, it is difficult to make the above members into a composite material in terms of hardness and size. Inadequate production due to lack of accuracy. Also, in order to fix the blade to the hub and allow the blade to rotate around the pitch conversion axis, it is necessary to provide the bearing race part on the composite material blade, but the bearing race is manufactured by FRP in terms of hardness and dimensional accuracy. It is difficult.

Therefore, as the construction of the blade shank portion, for example, as shown in FIG. 3, the tip of the metal guide member 21 is inserted into the space portion around the pitch conversion axis provided at the root portion of the composite material spar 20. And needle bearings 23 and 2
There is proposed a configuration in which the cylindrical member 22 fixed to the root of the blade spar 20 and the outer peripheral surface of the guide member 21 are connected by a ball bearing 25 so as to be rotatably connected with each other at 4.

[0005]

The composite material spar 20 is a strength member that transmits the centrifugal force and moment of the blade to the hub, and the torsion moment around the pitch conversion axis to the variable pitch mechanism. The root of the girder 20 is exposed to the outside, and the structure is easily affected by foreign matter such as sand, pebbles, ice, and birds. In addition, if the strength member is damaged and deteriorated due to the impact of foreign matter, the strength is lowered and it is dangerous.

According to the present invention, in the structure of the shank portion of the composite material blade for connecting the composite material spar and the metal member, the structure is such that the spar is not damaged by foreign matter impact or its strength is deteriorated. It is intended to provide a shank structure for a composite blade.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a shank portion structure of a composite material blade for connecting a composite material spar and a metal or composite material guide member to an intermediate layer on the exposed shank portion of the shank portion. 1 is a shank portion structure of a composite material blade, characterized in that a protective sleeve is covered with a material. More specifically, in the shank portion of the composite material spar provided in the longitudinal direction inside the composite material shell having the blade-shaped outer shape forming the blade, the sleeve of another material is provided through the intermediate layer having a low elastic modulus. Is a composite material blade that protects the composite spar by installing a high toughness and high impact strength sleeve to increase the impact strength of the blade, and even if the sleeve is damaged due to foreign matter impact, it has a low elastic modulus intermediate The layer is a shank part structure of a composite blade having a high damage tolerance, which prevents a damage crack from propagating to a composite spar.

The present invention uses a protective sleeve to increase the impact strength of a composite spar, and the protective sleeve has high toughness and high impact strength, such as steel, titanium, aluminum, and FRP using a high toughness fiber. Materials are available.
Further, a material having a relatively low elastic modulus is suitable for the intermediate layer material, and for example, a material such as GFRP, a nylon sheet, or a polyester sheet can be used.

In the present invention, the structure of the target shank portion is not particularly limited, but as shown in the embodiment, the shank portion of the composite material blade for connecting the composite material spar to the metal or composite material guide member. In the structure, on the outer peripheral surface of the guide member, groove portions parallel to the axial direction of the composite material spars and into which a part of the connecting bar material can be fitted are arranged at predetermined intervals, and similarly, the root end face of the spars. Grooves into which a part of the bar material can be fitted are arranged at a predetermined interval on the inner peripheral surface of the concave portion provided in, and the tip of the guide member is fitted and adhered to the concave portion of the blade spar with the bar material interposed in the groove portion. It is fixed and has a structure in which a ring is arranged and tightened around the outer periphery of the blade spar, and for connecting the hub and the variable pitch mechanism to the outer peripheral surface of the root portion of the blade spar and the root end surface and outer peripheral surface of the guide member. Characterized by forming an uneven portion on which a member can be mounted Shank structure of the composite material blade is optimal. That is, in such a configuration, since the centrifugal force of the blade is transmitted to the hub by the mechanical connection from the composite spar, the phenomenon of pulling out of the spar does not occur, and the moment around the pitch conversion axis of the blade is bonded. Although it is transmitted to the guide member via the agent, even if the adhesive between the spar and the guide member peels off, the transmission path is secured by the mechanical connection between the spar and the guide member, and the centrifugal force from the spar to the guide. Is not transmitted, the guide member bears only the stress due to the torsional moment, which simplifies the design and enables reliable transmission of the load from the composite material blade to the hub and variable pitch mechanism. Since the mechanism in which the stress concentration occurs is eliminated as much as possible, the high strength characteristics of the composite material such as FRP are not deteriorated, and the structure is simpler than that of conventional products. Since processing efficiency is good, which is optimal for the shank part structure of the present invention.

[0010]

According to the present invention, by covering the exposed spars of the shank portion with the protective sleeve through the intermediate layer material, the blade shank portion is located outside the hub and the like and is exposed to the outside. When a foreign matter impact is applied to the area, the impact is absorbed by the girder protection sleeve, which has high toughness and high impact strength,
Even if the impact is large, stop damage to the girder protection sleeve,
Since the girder protection sleeve and the composite girder are in contact with each other through the intermediate layer 13 having a low elastic modulus, damage cracks can be prevented from propagating to the composite girder.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a cross-sectional explanatory view of a main part showing a shank portion structure of a composite material blade according to the present invention, A is a cross-sectional explanatory view in the axial direction of the spars, and B is a cross-section taken along line BB in A. FIG. 2 is an explanatory cross-sectional view in the axial direction of the spars showing another shank structure according to the present invention. The composite wing spar 1 is provided in the longitudinal direction in a composite shell 2 having an outer shape of a wing shape, and a groove portion 1a is formed on the outer peripheral surface of the root portion thereof.
A filler 3 is filled in the space with the composite wing spar 1 therein. In addition, the root portion of the composite material spar 1 is provided with a projection 1b having a required shape so that the bearing race 10 can be mounted, and the end face is provided with a recess into which the guide member 4 can be fitted. is there.

The guide member 4 has groove portions 4a, which are parallel to the axial direction of the composite material spar 1 and into which a part of the connecting bar material 5 can be fitted, are arranged at predetermined intervals on the outer peripheral surface of the guide member 4, and A bearing race 10 can be mounted by providing a concave portion 9 of a required shape on the outer periphery, and a roller
An eccentric pin 7 fitted with a bearing 8 is provided. The composite material spar 1 and the guide member 4 are fixed by adhesion by inserting the tip of the guide member 4 into the recess of the composite material spar 1 with the connecting bar member 5 interposed in the groove. Further, instead of the connecting bar member 5 in FIG. 1, an integral or split type cylindrical member 5a or a plurality of arc-shaped members in cross section may be used as shown in FIG.

Bearing balls 1 for mounting bearing races 10 at the roots of the composite spar 1 and guide member 4.
Reference numeral 1 denotes a blade hub 12 that is rotatably supported around a pitch conversion shaft 13, and is in contact with the blade via a bearing race 10. The root region of the blade configured as described above is called a shank portion.

In the above structure, the spar protection sleeve 16 made of FRP is bonded and integrated to the exposed portion of the composite material spar 1 of the shank through the intermediate layer 15 made of GFRP. Further, here, a two-piece ring 14 is bolt-nut coupled to the outer periphery of the composite wing spar 1 on the tip end side of the guide member 4 and is tightened. blade·
When a foreign matter impact is applied to the area exposed outside, inside the shank, outside the hub, etc., the impact is high in toughness,
Absorb by the girder protection sleeve 16 with high impact strength, and stop damage to the girder protection sleeve 16 even when the impact is large,
The spar protection sleeve 16 and the composite material spar 1 are brought into contact with each other through the intermediate layer 15 having a low elastic modulus to prevent propagation of damage cracks to the composite material spar 1.

With the above construction, the centrifugal force and bending moment of the blade are transmitted from the composite spar 1 to the hub 12 that supports the blade via the bearing race 10 and the bearing balls 11. The moment generated by the blade about the pitch conversion shaft 13 is transmitted to the variable pitch mechanism via the composite material spar 1, bar material 5, guide member 4, eccentric pin 7, and roller bearing 8. Further, the ring 14 tightens the outer peripheral portion of the composite spar 1 to improve the hoop strength of the spar 1.

[0016]

The shank portion structure of the composite material blade according to the present invention has the following operational effects. Foreign matter impact received by the blade / shank is absorbed by the girder protection sleeve with high impact strength, and the blade is not damaged. Even when subjected to a large impact, damage due to foreign matter impacts is stopped inside the spar protection sleeve, and the propagation of damage cracks is prevented in the composite material spar which is critical to structural safety. Therefore,
Although damage to the composite spar, which is a strength member, poses a threat to the safety of the propeller system, the blade is protected by adhesively integrally fixing the spar protection sleeve to the composite spar through the intermediate layer. The damage tolerance of is improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of a main part showing a shank portion structure of a composite material blade according to the present invention, where A is a cross-sectional explanatory view in the axial direction of a blade spar, and B is a BB cross section in A.

FIG. 2 is a cross-sectional view in the axial direction of a spade showing another shank structure according to the present invention.

FIG. 3 is a perspective explanatory view showing a shank portion structure of a conventional composite material blade.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Composite material spar 1a, 4a Groove 1b Projection 2 Composite material shell 3 Filler 4 Guide member 5 Connecting bar material 5a Cylindrical member 6 Root 7 Eccentric pin 8 Roller bearing 9 Recess 10 Bearing race 11 Bearing・ Ball 12 Blade hub 13 Pitch conversion shaft 14 Ring 15 Intermediate layer 16 Blade spar protection sleeve 20 Composite blade spar 21 Guide member 22 Cylindrical member 23, 24 Needle bearing 25 Ball bearing

Claims (1)

[Claims] 1. In a shank portion structure of a composite material blade for connecting a composite material spar and a metal or composite material guide member, the exposed spar portion of the shank portion is covered with a protective sleeve via an intermediate layer material. The shank part structure of the composite material blade characterized by the above.