JPH0427079B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wing structure for an aircraft. especially,
The present invention relates to a leading edge protection structure in an aircraft wing structure. The leading edge protection structure for an aircraft wing according to the present invention can be widely applied not only to fixed wings but also to rotary wing blades, propeller blades, etc. of rotary wing aircraft.

[Prior art]

During use, aircraft wing structures are exposed to impact from foreign objects such as dust and water droplets contained in airflow.
In particular, the leading edge of a rotary wing of a rotary-wing aircraft that travels through the air at high speed is subject to severe wear due to these foreign substances, and in many cases a protective member is used to protect the leading edge. In the well-known structure, these protective members are formed from a rubber material or a metal material such as nickel or stainless steel to match the shape of the blade leading edge, and are attached to the blade leading edge.

In these known structures, if rubber materials are used, the durability against dust is satisfactory, but
It is extremely vulnerable to the impact of water droplets, and when used as a leading edge protection member for rotor blades of rotorcraft, it has the disadvantage that it will break in just a few minutes during flight in the rain. In addition, using metal materials with excellent corrosion resistance such as nickel or stainless steel improves wear resistance against dust and water droplets, but
This cannot be said to be completely satisfactory; surface roughness occurs within a short period of time, deteriorating the performance of the blade, and the protective member must be replaced after a certain period of time. This wear problem is particularly acute in the case of the rotor blades of rotary wing aircraft, which fly at low altitudes, kicking up dust, and rotating in it.

Conventionally, the rotor blades of rotorcraft have been thought to have a finite lifespan due to fatigue caused by severe repeated loads during flight. However, with the recent development of rotor blades that use composite materials, they can now be expected to have an infinite structural lifespan. This composite material rotor blade also requires a leading edge protection member, and this leading edge protection member experiences wear as described above. Generally, the protective member is bonded to the blade root body using an organic adhesive, so it is extremely difficult to replace the protective member without damaging the blade root body. Therefore, in rotor blades made of composite materials, wear of the protective member is a factor that determines the lifespan of the blade.

Ceramic materials are considered as materials with excellent wear resistance against dust and water droplets. However, ceramic materials have extremely brittle properties, and even the slightest defect during manufacturing causes high stress concentration in the defective portion, causing breakage. Manufacturing defects that cause this breakage occur to some extent according to statistical laws, and the breakage rate increases in proportion to the size of the ceramic product. Furthermore, even if the protection member is damaged in one place, the entire protection member needs to be replaced, so it is necessary to improve the reliability of the protection member, which increases the manufacturing cost.

[Problem that the invention seeks to solve]

An object of the present invention is to solve the problem of shortened lifespan due to wear in leading edge protection members of aircraft wings. More specifically, it is an object of the present invention to provide a leading edge protection structure in which wear of the leading edge protection member does not affect the life of the blade.

[Means for solving problems]

In order to solve the above problems, in the present invention, a plurality of protection members having a shape forming a curved surface of the leading edge of the wing are arranged continuously in the longitudinal direction of the wing, and these protection members are arranged at the end of the wing. They are overlapped and bonded to each other, and are also bonded to the wing body.

In the present invention, the protective member is made of ceramic material. Furthermore, it is preferable that the protective member be formed so that the thickness is thick at the leading edge and thin at the trailing edge, and the end portion has a flat surface having an angle of 30° to 60° with respect to the longitudinal direction of the wing. It is preferable to form it into a shape.

〔effect〕

In the present invention, the protective member is divided into a plurality of parts and these parts are arranged continuously in the longitudinal direction of the blade. Therefore, even when these protective members are made of ceramic material, the size of the member can be reduced. As a result, the probability of manufacturing defects that cause damage can be reduced.
Moreover, even if one member is damaged, only the damaged member needs to be replaced, and a highly practical protective structure can be obtained. Furthermore, since the protective members are overlapped and bonded to each other at their ends, wear at the boundaries of the protective members can be reduced.

At the leading edge of the protection element, the protection element is subject to heavy wear, but the bending loads are relatively small. On the other hand, at the rear edge of the protection member, the wear is slight, but the bending load is high. In a preferred embodiment of the present invention, the protective member is thick at the front edge and thin at the rear edge. According to this configuration, an increase in weight can be kept to a minimum. Furthermore, if the protective member is damaged, it is thought that the damage will occur at the trailing edge where stress is high, but since the trailing edge of the protective member is formed thin, damage to the protective member is prevented from affecting the wing body. can be kept to a minimum. Therefore, the reliability of the entire wing can be improved.

〔Example〕

Hereinafter, an embodiment in which the present invention is applied to a rotary wing blade of a rotary wing aircraft will be described.

First, in FIG. 1, the front edge 1a of the blade structure 1
A protective structure 2 is provided. The protective structure 2 is made up of a plurality of protective members 2a made of a ceramic material with high strength and high hardness, and these protective members 2a are arranged continuously in the longitudinal direction of the blade structure 1. These protection members 2a are the fourth
As shown in the figure, it is bonded to the blade structure 1 with an adhesive 3.

As shown in FIG. 2, one end 2c of the protective member 2a is formed one step lower by the thickness of the adjacent protective member, and the end 2b of the adjacent protective member 2a is placed on this end 2c. are arranged so that they overlap.
As for the arrangement, it is preferable that the outer protection member overlaps the inner protection member when viewed in the longitudinal direction of the blade. Among the protective members, the outermost protective member is the most susceptible to damage, but with this arrangement, the outermost protective member 2a overlaps the innermost protective member 2a, making it easier to replace. for easy removal. Furthermore, by overlapping the ends of adjacent protection members 2a, it is possible to prevent wear at the boundary between the protection members. Further, the size of the protective member 2a can be set to a size that is most difficult to form defects and is easy to handle, so that structural reliability can be ensured.
Since the protective members can have the same shape except for the outermost part, large processing equipment is not required and the manufacturing cost can be reduced.

At the end, each protective member 2a has an edge not perpendicular to the longitudinal direction, but at an angle of less than 90°, for example 30° to 60°. This shape can alleviate stress concentration at the ends of the protection member and prevent adhesive peeling and damage to the blade structure at the ends of the protection member due to stress concentration. Further, since the direction of the boundary portion of the protective member is deviated from the direction of the air flow, wear of the boundary portion can be minimized.

As shown in FIG. 4, each protection member 2a is formed so that the rear edge 2d, which is subject to relatively little wear and high stress due to aerodynamic load, is thin, and the front edge 2e, which is subject to severe wear and low stress, is thick. With this configuration, it is possible to suppress the increase in gravity due to the protection member as much as possible, thereby enhancing the protection effect. Furthermore, even if damage occurs at the highly stressed trailing edge, stress concentration on the blade base body 1 at the damaged area can be kept to a minimum, and damage to the protective member can be prevented from leading to damage to the blade base body 1. .

FIG. 5 shows another embodiment of the present invention,
The protective structure is composed of protective members 5 having the same size as the protective member 2a of the previous example and a protective member 4 having a small size disposed between these protective members 5.
The protection member 4 has a substantially triangular cross-sectional shape, and a slope 5a is formed at an edge of the protection member 5, overlapping with a slope 4a of the protection member 4 having a triangular cross-section. According to this configuration, all the protection members 5 can be replaced individually.

When manufacturing protective members, ceramic materials are sintered in advance into a predetermined shape, such as a flat plate shape or a shape approximating a predetermined airfoil shape, and are then subjected to superplastic processing at high temperatures to form the desired airfoil shape. conduct. According to this method, the shape accuracy can be increased and the surface can be finished into a mirror finish.

Note that if the protective member is formed of a ceramic material and its surface is finished to a mirror finish, the mirror finish can be maintained for a long period of time due to the high wear resistance of ceramic. The performance of a wing is greatly affected by the surface roughness of the leading edge, and can be greatly improved by finishing it to a mirror surface. With a metal protective member, the surface becomes rough in a short time, so there is no practical point in finishing it to a mirror finish, but a ceramic protective member with a mirror finish can greatly improve the performance of the wing.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a rotary wing blade for a rotary wing aircraft showing an embodiment of the present invention, Fig. 2 is a perspective view showing the structure of a protection member, and Fig. 3 is an enlarged view showing a joint part of the protection member. 4 is a cross-sectional view showing a preferred cross-sectional shape of the protective member, and FIG. 5 is a cross-sectional view showing another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Rotor blade blade body, 2... Protective structure, 2a
...protective member, 3...adhesive, 4...protective member,
5...Protective member.

Claims (1)

[Scope of Claims] 1. A leading edge protection structure for an aircraft in which a protection member having a shape forming a curved surface of the leading edge of the wing is arranged to extend in the longitudinal direction of the wing and is coupled to the wing body, comprising: (a) The leading edge protection member is formed of a ceramic material, (b) the leading edge protection member is formed by being divided into a plurality of parts along the longitudinal direction of the wing, and (c) the divided leading edge protection member is formed of a ceramic material. A leading edge protection structure for an aircraft wing, characterized in that a plurality of parts of the member are overlapped and connected to each other at their ends. 2. The leading edge protection structure for an aircraft wing according to claim 1, wherein the protection structure is formed to have a thick wall at the leading edge and a thin wall at the trailing edge. 3. The aircraft wing according to claim 1 or 2, wherein the protective member is formed in a planar shape having an angle of 30° to 60° with respect to the longitudinal direction of the wing at the end portion. Leading edge protection structure.