A bearingless blade connection structure

Abstract

The application belongs to the technical field of helicopter rotor structure, and particularly relates to a bearingless blade connecting structure. The bearingless blade connecting structure comprises a flexible beam, two support bearings, a support bearing support, a support fixing bolt, a cover plate, a cover plate connecting bolt, a wear plate, a tail shaft, a blade and a tail rotor flange. One end of the flexible beam is provided with one piece of blade, and the flexible beam is integrally formed with the blade. The blade root is connected with the tail rotor flange through a bolt. The support bearing support is fixed on the flexible beam through the support fixing bolt to support the two support bearings on the upper and lower sides of the flexible beam. One end of the support bearing is connected with the tail rotor flange, and the other end of the support bearing is connected with the support bearing support. The flexible beam is clamped between the cover plate and the tail shaft. The wear plate is arranged on the clamping interface between the cover plate and the flexible beam, and is fixed by the cover plate connecting bolt.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of helicopter rotor structure, and particularly relates to a bearingless blade connecting structure. BACKGROUND

[0002] The bearingless tail rotor is an advanced tail rotor configuration, which has been applied to multiple helicopter models at home and abroad. The tail rotor blade assembly mainly consists of a flexible beam, a sleeve and a tail rotor blade airfoil section. Since the flexible beam and the sleeve are not synchronous in movement, a double-path force transmission structure is designed. The sleeve is adhesively connected to the flexible beam near the blade tip and is connected to the root through a support bearing, wherein the support bearing is a pair of elastic bearings with three translational stiffness and three rotational stiffness. The flexible beam is the core component of the bearingless tail rotor, which replaces the horizontal hinge, vertical hinge and axial hinge of the traditional hinged tail rotor, and realizes the flapping, pitching and variable pitch movement of the blade through elastic deformation.

[0003] The most difficult part in the design of the bearingless tail rotor is the long-life design of the central connecting area and the flapping deformation area. The tail rotor flexible beam has exposed a series of problems such as high scrap rate, early damage leading to scrap during use and flexible beam fracture under large load during use due to insufficient life margin. SUMMARY

[0004] The application aims to provide a bearingless blade connecting structure, which reduces the strain of the flexible beam connecting area and improves the service life of the flexible beam.

[0005] TECHNICAL SOLUTION

[0006] The bearingless blade connecting structure comprises a flexible beam 1, two support bearings 2, a support bearing bracket 3, a bracket fixing bolt 4, a cover plate 6, a cover plate connecting bolt 7, a wear-resistant plate 8, a tail shaft 9, a blade 10 and a tail rotor flange 11, wherein,

[0007] One end of the flexible beam 1 is provided with one piece of blade 10, and the flexible beam 1 is integrally formed with the blade 10. The root of the blade 10 is connected to the tail rotor flange 11 through a bolt, and the support bearing bracket 3 is fixed on the flexible beam 1 through the bracket fixing bolt 4 to support the two support bearings 2 on the upper and lower sides of the flexible beam 1. One end of the support bearing 2 is connected to the tail rotor flange 11, and the other end of the support bearing 2 is connected to the support bearing bracket 3. The flexible beam 1 is clamped between the cover plate 6 and the tail shaft 9, and a wear-resistant plate 8 is arranged on the clamping interface between the cover plate 6 and the flexible beam 1, and is fixed by the cover plate connecting bolt 7.

[0008] Further, the thickness of the central region of the flexible beam 1 is greater than that of other regions, the stiffness is improved to reduce the strain, and the deformation area of the flexible beam 1 is moved outward.

[0009] Further, the flexible beam 1 is provided with protruding ears on both sides, and the tail shaft 9 is provided with an upturned edge, which is in shape with the protruding ears on both sides of the flexible beam 1 and is used for mechanically limiting the flexible beam 1, so as to prevent the flexible beam from rotating along the central tail shaft and causing abrasion.

[0010] Further, the flexible beam 1 is fixed with the cover plate 6 through four cover plate connecting bolts 7.

[0011] Further, the support bearing support 3 is connected with the deformation area of the flexible beam 1 through a support middle bolt 5.

[0012] Further, the wear-resistant plate 8 is thick on both sides and thin in the middle, and the abutting surface of the flexible beam 1 is designed as an arc surface, so as to be closely attached to the flexible beam 1, reduce the pressing force of the flexible beam 1 on the edge of the wear-resistant plate 8 during deformation, and reduce local stress concentration.

[0013] Further, the connection hole area of the flexible beam 1 in the length direction is disconnected with the deformation area of the flexible beam 1 through a crescent groove, so as to avoid extrusion of the flexible beam 1 on the edge of the cover plate 6 during deformation, and cause stress concentration.

[0014] Further, the central area of the flexible beam 1 is thickened by increasing a laying layer or a large beam.

[0015] Beneficial effects:

[0016] The application provides a structure for a bearingless tail rotor flexible beam connection area, which is proved to effectively reduce the strain of the flexible beam connection area and significantly prolong the service life of the flexible beam, and can be applied to all bearingless rotors / tail rotors. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a schematic diagram of a bearingless tail rotor, which shows the connection relationship of a flexible beam 1, a support bearing 2, a rotor blade 10 and the like.

[0018] Figure 2 It is a schematic diagram of a central connection area, which shows the connection relationship of a central flexible beam 1, a cover plate 6 and a tail shaft 9.

[0019] Figure 3 It is a schematic diagram of a wear-resistant plate shape.

[0020] Figure 4 It is a schematic diagram of a central flexible beam.

[0021] Figure 5 It is a schematic diagram of a wear-resistant plate shape affecting the strain of a central flexible beam connection area.

[0022] Wherein, the flexible beam 1, the support bearing 2, the support bearing support 3, the support fixed bolt 4, the support middle bolt 5, the cover plate 6, the cover plate connecting bolt 7, the wear plate 8, the tail shaft 9, the paddle 10, the tail paddle flange 11. DETAILED DESCRIPTION

[0023] The bearingless paddle connecting structure of the application reduces the flexible beam load of the connecting area and improves the flexible beam life.

[0024] The following will be described with the tail paddle as an example in combination with the drawings.

[0025] As Figures 1-4 A bearingless paddle connecting structure, comprising: a flexible beam 1, a support bearing 2, a support bearing support 3, a support fixed bolt 4, a support middle bolt 5, a cover plate 6, a cover plate connecting bolt 7, a wear plate 8, a tail shaft 9, a paddle 10, and a tail paddle flange 11. One end of the flexible beam 1 is connected to one piece of paddle 10, wherein the paddle 10 is connected to the tail paddle flange 11 through a bolt, and the flexible beam 1 is fixed in the inner cavity of the root of the paddle 10. The flexible beam 1 and the root section of the paddle 10 are connected through two support bearings 2, the support bearings 2 are fixed on the support bearing support 3 through a bolt, the support bearing support 3 is fixed on the flexible beam 1 through the support fixed bolt 4, and a support middle bolt 5 is additionally arranged in the middle; the flexible beam 1 is clamped between the cover plate 6 and the tail shaft 9, a wear plate 8 is arranged on the clamping interface between the cover plate 6 and the flexible beam 1, and the cover plate connecting bolt 7 is used for fixation.

[0026] The central region of the flexible beam 1 is thickened by adding a layer or a large beam to improve its rigidity and reduce strain, so that the deformation region of the flexible beam 1 moves outward;

[0027] The two sides of the flexible beam 1 are provided with protruding lugs, which cooperate with the end faces of the two sides of the tail shaft 9 to increase mechanical limiting and prevent the flexible beam from being slightly rotated along the central tail shaft to cause wear;

[0028] The flexible beam 1 and the cover plate 6 are fixed through four cover plate connecting bolts 7; wherein the length direction connecting hole region and the deformation region of the flexible beam 1 are disconnected through a crescent slot, so as to avoid extrusion between the edge of the cover plate 6 and the deformation region of the flexible beam 1 when the flexible beam 1 deforms, and to cause stress concentration;

[0029] The support bearing 2 is fixed on the support bearing support 3, and the load is transmitted to the flexible beam 1 through the support bearing support 3, compared with the original scheme that the support bearing is directly bonded on the flexible beam 1, the connection reliability of the support bearing and the flexible beam can be further improved.

[0030] A connecting bolt support middle bolt 5 is additionally arranged in the middle of the support bearing support 3, which can move the deformation region of the flexible beam 1 outward to reduce the strain level of the flexible beam 1, thereby greatly improving the life of the flexible beam 1, such as Figure 5 .

[0031] The wear plate 8 is designed in a shape of thin in the middle and thick on both sides, wherein the abutting surface of the flexible beam 1 is designed as an arc surface, which is closely fitted with the flexible beam 1, so as to reduce the pressing force of the flexible beam 1 with the edge of the wear plate 8 in the deformation process, and reduce the local stress concentration.

[0032] The flexible beam 1 is mechanically fixed through the cover plate 6 and the supporting bearing 2, so as to more effectively prevent slight shaking of the flexible beam in the rotating process, reduce the wear of the surface of the flexible beam, and improve the service life of the flexible beam.

Claims

1. A bearingless blade connection structure, characterized in that, include: Flexible beam (1), two supporting bearings (2), supporting bearing bracket (3), bracket fixing bolts (4), bracket intermediate bolts (5), cover plate (6), cover plate connecting bolts (7), wear-resistant plate (8), tail shaft (9), blade (10), tail rotor flange (11), among which, A flexible beam (1) has a blade (10) at each end. The flexible beam (1) and the blade (10) are integrally formed. The root of the blade (10) is connected to the tail rotor flange (11) by bolts. The support bearing bracket (3) is fixed to the flexible beam (1) by the bracket fixing bolts (4) to support the two support bearings (2) on the upper and lower sides of the flexible beam (1). One end of the support bearing (2) is connected to the tail rotor flange (11), and the other end of the support bearing (2) is connected to the support bearing bracket (3). The flexible beam (1) is sandwiched between the cover plate (6) and the tail shaft (9). A wear-resistant material is provided on the clamping interface between the cover plate (6) and the flexible beam (1). Plate (8) is fixed with cover plate connecting bolts (7). Protruding lugs are added to both sides of the flexible beam (1). Upward flanges are provided on both sides of the tail shaft (9). The flange position is the same as the protruding lugs added to both sides of the flexible beam (1) to mechanically limit the flexible beam (1) and prevent the flexible beam from slightly rotating along the central tail shaft, which would cause wear. The middle bolt (5) of the bracket connects the support bearing bracket (3) to the deformation area of ​​the flexible beam (1). The wear-resistant plate (8) is thin in the middle and thick on both sides. The mating surface with the flexible beam (1) is designed as an arc surface, which fits tightly with the flexible beam (1) to reduce the clamping force between the flexible beam (1) and the edge of the wear-resistant plate (8) during the deformation process and reduce local stress concentration.

2. The bearingless blade connection structure according to claim 1, characterized in that, The thickness of the central region of the flexible beam (1) is greater than that of other regions, which increases its stiffness to reduce strain, causing the deformation zone of the flexible beam (1) to move outward.

3. The bearingless blade connection structure according to claim 1, characterized in that, The flexible beam (1) and the cover plate (6) are fixed by four cover plate connecting bolts (7).

4. The bearingless blade connection structure according to claim 1, characterized in that, The connecting hole area along the length of the flexible beam (1) is separated from the deformation area of ​​the flexible beam (1) by a crescent groove, so as to avoid the flexible beam (1) from being squeezed against the edge of the cover plate (6) when it deforms, which would lead to stress concentration.

5. The bearingless blade connection structure according to claim 1, characterized in that, The central area of ​​the flexible beam (1) is thickened by adding ply or beam strip.

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