Main reducer connecting structure of helicopter

Abstract

The utility model provides a helicopter main speed reducer connecting structure which comprises a frame beam structural section arranged below a helicopter main speed reducer. One end of the supporting rod connecting section is connected with the frame beam structure section, and the other end of the supporting rod connecting section is connected with the helicopter main speed reducer; the frame beam structure section comprises a transversely-arranged frame, a longitudinally-arranged beam, an upper connecting plate and a lower connecting plate, wherein the upper connecting plate and the lower connecting plate are connected with the frame beam. Wherein supporting rod connecting holes are formed in accessories at the two ends of the transversely arranged frame; the main speed reducer is installed and supported by adopting the structural form that the eight supporting rods form the supporting bracket, and the size and the weight of the main speed reducer casing are reduced.

Description

Technical Field

[0001] This application belongs to the technical field of helicopter structure design, and particularly relates to a connecting structure of a helicopter main reducer. Background Technique

[0002] The helicopter reduces the high rotational speed of the engine to the low rotational speed of the rotor through the main reducer. It is one of the main moving components of the helicopter and also the component with the highest complexity, the largest structural size, and the heaviest weight in the transmission system. The main reducer uses gear transmission to reduce the rotational speed of the input shaft, increase the torque of the output shaft, and change the transmission direction. Its input shaft (drive shaft) is connected to the output shaft (driven shaft) of the engine, and its output shaft is the rotor shaft.

[0003] In the early stage, the installation of the helicopter main reducer was generally installed on the load-bearing frame beam through the main reducer casing. For example, the steel casing at the bottom of the main reducer of the US UH-1 helicopter is connected to the fuselage structure frame beam. Although the structure is simple, the connection points are generally in the middle of the frame beam, which will result in an indirect force transmission path, thereby increasing the structural weight. And the force on the casing connection point deviates far from the center of the main reduction force. To ensure the strength and stiffness requirements, the weight of the casing is relatively large. Utility Model Content

[0004] In view of the above technical problems, this application provides a connecting structure of a helicopter main reducer, and the connecting structure includes:

[0005] A frame beam structure section, which is arranged below the helicopter main reducer;

[0006] A strut connection section, one end of the strut connection section is connected to the frame beam structure section, and the other end of the strut connection section is connected to the helicopter main reducer.

[0007] Preferably, the frame beam structure section includes a horizontally arranged frame, a longitudinally arranged beam, and upper and lower connecting plates connected to the frame beam; wherein, strut connection holes are arranged at the ends of the horizontally arranged frame.

[0008] Preferably, the strut connection section includes a plurality of strut assemblies, and each strut assembly is composed of a strut rod body and upper and lower strut joints.

[0009] Preferably, the strut rod body is a constant cross-section structure, and the cross-sectional shape can be circular or annular; the upper strut joint is a double-ear connection joint; the lower strut joint is a rod-shaped joint, and the rod-shaped joint is mainly composed of two parts of rods.

[0010] Preferably, the helicopter main reducer includes a plurality of single-ear joints, and the single-ear joints are located on the outer side of the upper and middle parts of the main reducer, and 2 are arranged on each of the front and rear sides and the left and right sides.

[0011] Preferably, the double-ear connection joint is connected to the single-ear joint, and the rod-shaped joint is connected to the strut connection hole.

[0012] Advantageous technical effects of the present application:

[0013] The present application adopts a structural form in which 8 struts form a support bracket to install and support the main reducer, reducing the size and weight of the main reducer casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is an overall schematic diagram of the connection structure provided by the embodiment of the present application;

[0015] Figure 2 It is a schematic diagram of the structure of the frame provided by the embodiment of the present application;

[0016] Figure 3 It is a schematic diagram of the structure of the strut assembly provided by the embodiment of the present application;

[0017] Figure 4 It is a schematic diagram of the structure of the beam provided by the embodiment of the present application;

[0018] Figure 5 It is a schematic diagram of the structure of the upper and lower connecting plates provided by the embodiment of the present application;

[0019] Figure 6 It is a cross-sectional view of the connection part of the upper joint of the strut provided by the embodiment of the present application;

[0020] Figure 7 It is a schematic diagram of the structure of the upper and lower connecting plates and the connection part provided by the embodiment of the present application;

[0021] Figure 8 It is a cross-sectional view of the connection part of the lower joint of the strut provided by the embodiment of the present application;

[0022] Figure 9 It is a partial schematic diagram provided by the embodiment of the present application;

[0023] Figure 10 It is a schematic diagram of the structure of the main reducer provided by the embodiment of the present application;

[0024] Among them, 1 - frame; 2 - beam; 3 - main reducer; 4 - strut assembly; 5 - upper and lower connecting plates; 11 - strut connection hole; 12 - reinforcing rib; 41 - strut rod body; 42 - upper strut joint; 43 - lower strut joint; 421 - lug; 422 - bolt hole; 431 - upper rod; 432 - upper hemispherical arc; 433 - lower hemispherical arc; 434 - lower rod; 435 - thread; 21 - front beam section; 22 - middle beam section; 23 - rear beam section; 51 - waist-shaped hole; 34 - single-ear joint of main reducer; 42 - upper strut joint; 61 - spherical plain bearing; 62 - clearance bushing; 63 - interference bushing; 64 - bolt; 65 - washer; 66 - nut; 22 - middle beam section; 23 - rear beam section; 71 - inner spherical arc bushing; 72 - inner spherical arc gasket; 73 - outer spherical arc gasket; 74 - boss nut; 711 - inner spherical arc; 721 - inner spherical arc; 731 - outer spherical arc; 741 - cylindrical boss; 742 - hexagonal boss; 743 - wire locking hole; 744 - cylindrical hole; 745 - threaded hole; 31 - main rotor output shaft; 32 - tail rotor output shaft; 33 - engine input shaft; 34 - single-ear joint. Detailed implementation manners

[0025] Please refer to Figures 1 - 10 , an embodiment of the present application provides a connection structure for a helicopter main reducer, including a frame-beam structure section, a strut connection section, and a main reducer.

[0026] In the embodiment of the present application, the frame-beam structure section is located below the strut connection section of the helicopter main reducer, and includes a horizontally arranged frame, a longitudinally arranged beam, and upper and lower connecting plates connected to the frame and beam.

[0027] Among them, the frame is an I-shaped cross-section integrated machine plus frame, and 2 strut connection holes are arranged at each end of the frame; the connection holes are relatively large in size, penetrate the upper and lower flanges of the frame, and the cross-sectional size of the frame near the connection holes increases accordingly, and the sizes of the upper and lower flanges increase; at the middle position between the 2 strut connection holes, there is 1 reinforcing rib in the front and rear directions of the frame; the longitudinal beam is mainly composed of left and right longitudinal beams, and each side longitudinal beam consists of front, middle, and rear sections; the beam cross-section is an I-shaped cross-section, and the upper and lower flanges of the front and rear beam sections are wider on the side close to the middle section and narrower on the side far from the middle section, and a chamfer is used for transition between the wider flange and the narrower flange, and the chamfer slope is not greater than 45°; the upper and lower flanges of the middle beam section are wider on the side close to the front and rear beam sections and narrower in the middle part, and a chamfer is used for transition between the wider flange and the narrower flange, and the chamfer slope is not greater than 45°.

[0028] Among them, the upper and lower connecting plates are octagonal, with an opening in the middle, and the shape of the opening is a waist-shaped hole, and the size of the waist-shaped hole is determined according to the connection requirements; the above-mentioned frame, beam, and upper and lower connecting plates are connected into a whole by rivets, wherein the upper and lower connecting plates are respectively connected to the upper and lower flanges of the frame and beam, and the beam web is connected to the reinforcing rib of the frame.

[0029] Among them, the strut connection section is located above the frame beam connection section and includes a total of 8 strut assemblies; each strut assembly consists of a strut rod body and upper and lower strut joints; the strut rod body has a constant cross-section, and the cross-sectional shape can be circular or annular; the upper strut joint is a double-ear connection joint, with two ear plates symmetrically arranged, and there are bolt holes in the ear plates; the lower strut joint is a rod-shaped joint, which is mainly composed of two parts of rods. The axis of the upper rod and the axis of the lower rod intersect at a point and form an obtuse angle; there is a hemispherical arc surface at the upper and lower parts of the intersection point. The diameter of the upper hemispherical arc surface is larger and is connected to the upper rod, and the diameter of the lower hemispherical arc surface is smaller and is connected to the lower rod; the centers of the upper and lower hemispherical arc surfaces are the intersection points of the axes; the end of the lower rod has a thread; the above-mentioned strut assembly can be an integrally formed part, or an assembly composed of a strut rod body and upper and lower strut joints through welding or mechanical connection, and the forming process can be machining, additive manufacturing, etc.

[0030] In the embodiment of the present application, the main reducer consists of a main rotor output shaft, a tail rotor output shaft, an engine input shaft, and 8 single-ear joints; the 8 single-ear joints are located on the outer side of the upper middle part of the main reducer, with 2 arranged on each of the front and rear sides and the left and right sides. The distance between the two ear plates on the front and rear sides is relatively far, and the distance between the ear plates on the left and right sides is relatively close; the directions of the ear plates on each side are the same, and the plane direction of the ear plates forms an acute angle with the angle of the main rotor output shaft and is parallel to the strut axis, and there are openings in the ear plates.

[0031] Among them, the connection structure between the strut connection section and the main reducer consists of an upper strut joint, a single-ear joint of the main reducer, a spherical plain bearing, an interference bush, a clearance bush, a bolt, and a nut; the single-ear joint of the main reducer is located between the two ear plates of the upper strut joint, and a spherical plain bearing is arranged at the opening of the single-ear joint of the main reducer. The width of the spherical plain bearing is greater than the width of the single-ear joint of the main reducer; the interference bush is connected to the opening of one ear plate of the upper strut joint, and the fitting form is an interference fit. The installation direction of the bush is from the middle of the upper strut joint to the outside, and the height of the bush is less than the thickness of the single-sided ear plate of the upper strut joint; the clearance bush is connected to the other ear plate of the upper strut joint, and the fitting form is a clearance fit. The installation direction of the bush is from the outside of the upper strut joint to the middle, and the height of the bush is greater than the thickness of the single-sided ear plate of the upper strut joint; the single-ear joint of the main reducer, the upper strut joint, and the bush are connected by bolts, washers, and nuts. The bolt and the clearance bush, the clearance bush and the spherical plain bearing, the spherical plain bearing and the interference bush, the washer and the ear plate of the upper strut joint, and the nut and the washer are all in a compressed state.

[0032] Among them, the connecting structure between the strut connecting section and the frame beam structure section is composed of a strut lower joint, a frame connecting hole, an inner spherical arc bushing, an inner spherical arc gasket, an outer spherical arc gasket, and a boss nut. The inner spherical arc bushing is a cylindrical shoulder bushing, and there is a hemispherical arc surface at the inner hole near the convex surface. The center of the hemispherical arc surface is located on the axis of the bushing. The diameter of the hemispherical arc surface is the same as the diameter of the lower hemispherical arc surface of the strut lower joint. The inner hole diameter of the inner spherical arc bushing is equal to the frame connecting hole; there is a bushing press-in hole at the upper end of the frame connecting hole. The press-in hole is coaxial with the connecting hole. The diameter of the press-in hole is larger than the diameter of the connecting hole. The length of the press-in hole is greater than the height of the inner spherical arc bushing. The diameter of the frame connecting hole is larger than the diameter of the lower rod of the strut lower joint; the inner spherical arc gasket is a circular gasket, and there is a through hole in the middle of the circular gasket. The diameter of the through hole is not less than the diameter of the frame connecting hole.

[0033] In other embodiments of the present application, there is a spherical arc surface at one end of the through hole of the circular gasket. The length of the spherical arc surface is less than the hemispherical arc. The center of the spherical arc surface is located on the axis of the through hole of the circular gasket; the outer spherical arc gasket is a circular gasket, and there is a through hole in the circle. The diameter of the through hole is equal to the diameter of the lower rod of the strut lower joint. There is a spherical arc surface on the outside of the circular gasket. The center of the spherical arc surface is located on the axis of the through hole of the circular gasket. The length of the spherical arc surface is greater than the length of the spherical arc surface of the inner spherical arc gasket; the upper end of the outside of the boss nut is arc-shaped, and the lower end is hexagonal. There is a horizontal through hole in the hexagonal section. The upper section of the inner hole of the boss nut is a cylindrical hole. The diameter of the cylindrical hole is larger than the diameter of the lower rod of the strut lower joint. The lower section of the inner hole of the boss nut is a threaded hole. The threaded hole is threadedly matched with the end of the lower rod of the strut lower joint; the inner spherical arc bushing is pressed into the bushing press-in hole of the frame, and the fit is an interference fit; the strut lower joint passes through the inner spherical arc bushing, the frame connecting hole, the inner spherical arc gasket, and the outer spherical arc gasket and is connected to the boss nut; among them, the lower spherical arc of the strut lower joint and the spherical arc of the inner spherical arc bushing form a spherical surface fit, the inner spherical arc gasket and the outer spherical arc gasket form a spherical surface fit, and the lower rod of the strut lower joint and the inner hole of the inner spherical arc bushing, the frame connecting hole, and the inner spherical arc gasket are in a large clearance fit, and are in a small clearance fit or an interference fit with the outer spherical arc gasket; the boss nuts of adjacent two struts are connected by lock wires.

[0034] In other embodiments of the present application, the present application uses a structural form of eight struts to form a support bracket to install and support the main reducer, reducing the size and weight of the main reducer casing; using the structure of the support bracket can significantly increase the clearance between the main reducer and the fuselage structure, reducing the occupation of the fuselage structure by the main reducer; the structure of the support bracket has strong adaptability. According to the installation requirements of different main reducers, only the length of the strut and the angle of the strut lower joint need to be adjusted as needed; the strut structure can be formed by integral molding or assembly molding. The assembly molding method has the advantages of flexible adjustment and simple maintenance and replacement.

[0035] Among them, the connection between the strut and the main reducer adopts a form of connecting the double-ear joint of the strut and the single-ear joint of the main reducer by a spherical plain bearing, a bushing and a bolt. There is a gapless tight fit between the single ear and the double ear, which is beneficial to the direct transmission of the load. The use of the spherical plain bearing makes the connection angle between the strut and the main reducer adjustable, reducing the difficulty of the assembly process; the connection points between the strut and the frame beam structure section are reasonably designed. The connection points between the strut and the frame beam structure section are all located at the intersection of the frame beams, and the strut load can be directly transmitted through the frame beam. The force transmission route is direct, without additional bending moment, avoiding the additional load generated by the additional bending moment, reducing the structural weight, improving the structural efficiency and having good reliability.

[0036] Among them, the frame beam connection is reasonably designed. It consists of a front frame, a rear frame and left and right longitudinal beams to form a grid structure, and the force transmission route is direct and efficient. The frame and beam structures are both formed by machining, with few parts, few connections, simple assembly and easy manufacturing; the force transmission design of the lower joint of the strut is reasonable. The intersection point of the lower joint of the strut is above the upper flange of the frame beam. Transmitting the lateral load of the strut will generate an additional bending moment, which is not good for the frame beam. The strut passes through the upper and lower flanges of the frame, and the additional bending moment is balanced by the upper and lower flanges. Among them, the upper flange transmits a larger lateral load through an inner spherical arc bushing, and the lower flange transmits a smaller lateral load through the friction between the inner spherical arc gasket and the frame flange.

[0037] Among them, the lower joint of the strut has an installation compensation function. The lower joint of the strut and the inner spherical arc bushing are in a spherical surface fit and can deflect a certain angle. The diameter of the lower part of the lower joint of the strut is smaller than the through-hole diameters of the inner spherical arc bushing, the frame connection hole and the inner spherical arc gasket, ensuring an adjustment gap between the lower structure of the strut and the above structures. The outer spherical arc gasket deflects relatively as the lower joint of the strut deflects, and the tight fit between the two is realized through the spherical surface fit deflection between the outer spherical arc gasket and the inner spherical arc gasket to transmit the lateral force, and the boss nut makes the spherical surface fit not loosen. This design can significantly reduce the position accuracy requirements of the main reducer connection for the opening of the structural frame beam, which is beneficial to the process assembly. The connection of the lower joint of the strut has a loosening prevention design. The lock wire is used to connect the boss nuts of two adjacent lower joints of the strut to achieve the function of connection loosening prevention.

Claims

1. A connecting structure of a helicopter main reduction gear, characterized in that, The connection structure includes: A frame beam structure section, which is arranged below the main reducer of the helicopter; A strut connection section, one end of the strut connection section is connected to the frame beam structure section, and the other end of the strut connection section is connected to the main reducer of the helicopter.

2. The connection structure according to claim 1, wherein, The frame beam structure section includes a horizontally arranged frame, a longitudinally arranged beam, and upper and lower connection plates connected to the frame beam; wherein, strut connection holes are arranged at the attachments at both ends of the horizontally arranged frame.

3. The connection structure according to claim 2, characterized in that, The strut connection section includes a plurality of strut assemblies, and each strut assembly is composed of a strut rod body and upper and lower strut joints.

4. The connection structure according to claim 3, wherein The strut rod body is of a constant cross-section structure, and the cross-sectional shape can be circular or annular; the upper strut joint is a double-ear connection joint; the lower strut joint is a rod-shaped joint, and the rod-shaped joint is mainly composed of two parts of rods.

5. The connection structure according to claim 4, characterized in that, The main reducer of the helicopter includes a plurality of single-ear joints, and the single-ear joints are located on the outer side of the upper middle part of the main reducer, and 2 are arranged on each of the front and rear sides and the left and right sides.

6. The connection structure according to claim 5, wherein The double-ear connection joint is connected to the single-ear joint, and the rod-shaped joint is connected to the strut connection hole.

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