RU2272750C2 - Attachment unit for helicopter main rotor blade - Google Patents

Abstract

FIELD: aeronautical engineering; construction of helicopter main rotors.

SUBSTANCE: proposed attachment unit includes hinge consisting of trunnion and body, torsion band and insert. In case of damage of bearing flange of insert, catcher is used which is mounted in cavity of trunnion; it is made in form of second bearing surface for end surface of insert. Laid between end surface of insert and second bearing surface is tubular gasket made from soft viscous material.

EFFECT: avoidance of after-effects at damage of insert.

2 cl, 4 dwg

Description

The invention relates to the field of aviation technology, in particular to the device of the rotors of helicopters. It can also be used in other variable pitch propellers, in the design of rotors of wind turbines and fan fans, as well as in other areas of technology where a flexible (torsion) connection between two structural elements is needed, for example, in a chassis of various types of vehicles or in special couplings .

Known mount the blades of the rotor of the helicopter, including an axial hinge, consisting of a journal and a housing interconnected by a torsion tape that receives centrifugal loads. The torsion tape is fixed with one of its loops by means of a finger installed in the aforementioned case, and the second loop - by means of a finger, installed in an insert located in the trunnion cavity (US Patent No. 3942910 by Tekstron, CL 416/141, 1976). The absence of a support flange at the insert greatly complicates and accordingly increases the cost of the design of the blade attachment unit, while reducing its reliability.

The closest in technical essence to the claimed design (prototype) is the rotor blade mount according to German patent No. 3838782 (class B 64 C 27/48, 1990) of the company "Messerschmitt-Bölkoff-Blom", including an axial joint, consisting of trunnions and hulls and a glass of butt lob attached to the trunnion. Mentioned trunnion and axial hinge body are interconnected by a centrifugal load-bearing torsion tape. The latter is fixed with one of its loops by means of a finger installed in the said housing, and the second loop - by means of a finger, which is mounted in a liner fixed from rotation and located in the trunnion cavity and having a supporting flange in contact with the corresponding supporting surface of the trunnion. The practice of operating a structure containing such a blade attachment unit on an Mi-26 helicopter showed its unreliability: there were cases of one of the rotor blades of the helicopter breaking off due to the destruction of the liner - the blade was torn off along with the torsion belt and the destroyed liner, which in catastrophic consequences .

The technical problem solved by the invention consists in the development of a more reliable mounting unit of the rotor blade of the helicopter, i.e. the design, devoid of the disadvantages of known analogues in terms of its complexity, high cost and unreliability, by creating a simple device to prevent catastrophic consequences when the liner is destroyed.

The specified technical problem is solved in that in the attachment unit of the rotor blade of the helicopter, including an axial hinge, consisting of a pin and a housing, and a cup of the blade of the blade attached to one of these structural elements, where the said pin and the axial hinge body are connected to each other by centrifugal loads torsion tape fixed with one of its loops by means of a finger installed in the aforementioned case, and the second loop - by means of a finger installed in fixed In the case of a hole located in the trunnion cavity and having a supporting flange in contact with the corresponding supporting surface of said trunnion, a liner catcher is installed in the trunnion cavity and made in the form of a second abutment surface for the end surface of the liner in case of destruction of the liner support flange. In this case, an annular gasket of a tubular profile made of soft viscous material, such as copper, is installed between the end face of the liner and said second supporting surface.

Figure 1 shows a longitudinal section of the inventive device; figure 2 is a section along aa of figure 1; figure 3 is a section along BB of figure 2 on an enlarged scale; figure 4 - node liner on an enlarged scale.

The mounting unit of the rotor blade of the rotor of the helicopter (Figs. 1, 2, 3) includes an axial hinge 1, consisting of a pin 2 and a body 3, and a glass 4 of the butt 5 of the blade 6, attached to the body 3 by bolts 7. The pin 2 is equipped with two eyes 2a for articulating it with a vertical hinge finger not shown in the drawings. The mentioned trunnion and the housing, interacting with each other through the rolling bearings 8 and 8a, are interconnected by a centrifugal load-bearing torsion tape 9. The latter is fixed by its right loop in the housing 3 by means of a finger 10, and by the left loop - by means of a finger 11 in the insert 12 installed in the cavity of the pin 2. In this case, the torsion belt interacts with the fingers 10 and 11 through the thimbles 13 and 13a, with the help of which its loops are formed. The liner 12 is equipped with a supporting flange 14 in contact with the corresponding annular supporting surface of the journal 2, and is fixed from turning by a pin 15.

In accordance with the technical problem solved by the invention, in case of destruction of the support flange 14 of the liner 12, a liner trap is provided in the structure, mounted in the cavity of the pin 2 and made in the form of a second supporting surface 16 (Fig. 4), interacting with the right end surface of the liner 12 At the same time, as is clearly seen in figure 4, between the end face of the liner 12 and said second supporting surface 16 is installed an annular gasket 17 of a tubular profile made of soft viscous material, such as copper.

The inventive attachment unit of the rotor blade of the helicopter operates as follows.

In the process of rotation of the rotor around its axis, the centrifugal force arising on the blade 6 is received by the pin 2, to which it is transmitted sequentially through the finger 10, the torsion belt 9, the finger 11 and the flange 14 of the liner 12. Moreover, the torsion belt 9, being a flexible element connection, does not prevent the rotation of the housing 3 of the axial hinge relative to the journal 2 in the specified range. This rotation of the housing 3, transmitted from the rotation mechanism of the blade, not shown in the drawings, is possible due to the presence of rolling bearings 8 and 8a. Through the glass 4, it is transmitted to the rotor blades 6, changing the angle of its inclination and thereby the rotor lifting force in the range from 0 to the specified maximum value necessary for lifting the helicopter into the air.

In the practice of operating Mi-26 helicopters, there were cases of detachment of one of the rotor blades of the helicopter due to the destruction of the flange 14 of the liner 12, which in flight led to catastrophic consequences. The blade was torn off together with the housing 3, the torsion belt 9 and the liner 12 devoid of the flange 14. To prevent such consequences, the proposed design of the blade attachment assembly provides a liner trap 12, described above and operating as follows. When the flange 14 is destroyed, the insert 12 with its right end abuts against the second supporting surface 16, crushing the copper tubular gasket 17, softening the impact. This prevents blade separation, and the corresponding device in the cockpit signals a breakdown. Upon receipt of such a signal, the pilot must immediately land the helicopter.

The proposed design of the rotor blade mount assembly of the helicopter passed bench tests and showed its high efficiency.

Information sources

1. DE 3838782 C1, 02/01/1990.

2. US 3885887, 05.27.1975.

3. US 3942910, 03/09/1976.

4. Manual for the technical operation of the Mi-26. - M., 1988; p. 4/5, fig. 2.

Claims (2)

1. The mounting unit of the rotor blade of the rotor of the helicopter, including an axial hinge, consisting of a pin and a body, and a bead of a blade of blades attached to one of these structural elements, said axle and the body of the axial hinge being interconnected by a centrifugal load-bearing torsion tape fixed by one of its own loop by means of a finger installed in the aforementioned housing, and the second loop - by means of a finger installed in a liner fixed from rotation, located in the trunnion cavity and having PORN flange in contact with its corresponding bearing surface of said trunnion, characterized in that in case of fracture of the supporting flange of the insert structure is provided in collector insert mounted in a cavity formed in the journal and a second bearing surface for the end surface of the insert. 2. The blade attachment assembly according to claim 1, characterized in that between the end face of the liner and said second supporting surface, a tubular profile gasket is made of soft viscous material, such as copper.

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