An aircraft fuselage structure and cargo carrying aircraft

Abstract

The utility model relates to an airplane fuselage structure and freight carrying airplane belong to aerospace technology field, solve the problem of the fuselage structure complexity of freight carrying airplane, big weight, low structure strength in the prior art. The utility model discloses longitudinal beam, fuselage partition frame and landing gear connecting support, fuselage partition frame is provided with multiple in the direction of airplane fuselage length side by side, multiple fuselage partition frames are connected with longitudinal beam, and landing gear connecting support is connected with at least one fuselage partition frame, wherein, at least one fuselage partition frame and landing gear connecting support are integrally formed. The utility model can realize reducing fuselage structure complexity, reducing weight, improving structure strength.

Description

Technical Field

[0001] This utility model relates to the field of aerospace technology, and in particular to an aircraft fuselage structure and a cargo carrier aircraft. Background Technology

[0002] The rapid development of global e-commerce has led to increasingly higher demands for timely logistics. Current cargo aircraft include converted manned cargo planes and dedicated cargo aircraft. Traditional aircraft fuselage structures primarily use aluminum alloys and steel, resulting in a low payload ratio. Cargo aircraft conversions often have low space utilization and poor maintainability. Existing heavy-duty cargo aircraft have complex fuselage structures, are heavy, and have a low payload ratio. Utility Model Content

[0003] Based on the above analysis, the present invention aims to provide an aircraft fuselage structure and a cargo aircraft to solve the problems of complex fuselage structure, large weight, and low structural strength of cargo aircraft.

[0004] The objective of this utility model is mainly achieved through the following technical solutions:

[0005] One aspect of this utility model is to provide an aircraft fuselage structure, including longitudinal beams, landing gear connecting brackets, and fuselage bulkheads;

[0006] Multiple fuselage bulkheads are arranged side-by-side along the length of the aircraft fuselage; the multiple fuselage bulkheads are connected to each other by the longitudinal beams; the landing gear connecting bracket is connected to at least one of the fuselage bulkheads;

[0007] At least one of the fuselage bulkheads is integrally formed with the landing gear connecting bracket.

[0008] Furthermore, the fuselage frame includes a reinforcing frame, the cross-section of which is I-shaped;

[0009] The reinforcing frame includes a first reinforcing frame and a second reinforcing frame, which are disposed at the front end of the middle part of the fuselage. The first reinforcing frame and the second reinforcing frame are connected to the landing gear connecting bracket.

[0010] Furthermore, the first reinforcing frame and the second reinforcing frame include a frame body and a reinforcing structure disposed at the lower part of the frame body; the reinforcing structure of the first reinforcing frame extends into a first extension portion to both sides of the frame body, and the reinforcing structure of the second reinforcing frame extends into a second extension portion to both sides of the frame body.

[0011] Furthermore, the landing gear connecting bracket includes a main landing gear connecting bracket, which includes a first part and a second part. The first part and the second part are symmetrically arranged on both sides of the first reinforcing frame or the second reinforcing frame, respectively. The first part is connected to the first extension, and the second part is connected to the second extension. The first part is integrally formed with the first reinforcing frame, and the second part is integrally formed with the second reinforcing frame.

[0012] Furthermore, the top of the reinforcing structure of the first reinforcing frame and the reinforcing structure of the second reinforcing frame are provided with a top plate, and a keel beam is provided between the reinforcing structure of the first reinforcing frame and the reinforcing structure of the second reinforcing frame. The two ends of the keel beam are perpendicular and abut against the first reinforcing frame and the second reinforcing frame.

[0013] The first reinforcing frame, the second reinforcing frame, the top plate, and the keel beam together constitute the main cabin load-bearing structure of the aircraft.

[0014] Furthermore, the fuselage frame also includes a conventional frame, the conventional frame having a channel-shaped cross-section;

[0015] The ordinary frame includes a first ordinary frame, a second ordinary frame, and a third ordinary frame; the first ordinary frame, the second ordinary frame, and the third ordinary frame are located at the rear end of the middle part of the fuselage.

[0016] Furthermore, the lower part of the first ordinary frame, the second ordinary frame, and the third ordinary frame is provided with a side beam; the side beam is used to connect the tail landing gear;

[0017] The side beams are symmetrically arranged on both sides of the second ordinary frame; the first ordinary frame, the second ordinary frame, the third ordinary frame and the side beams together constitute the load-bearing structure of the aircraft's tail compartment.

[0018] Furthermore, the longitudinal beam includes a first longitudinal beam, a second longitudinal beam, a third longitudinal beam, a fourth longitudinal beam, and a floor beam arranged from the front end of the middle fuselage to the rear end of the rear fuselage;

[0019] The first, second, third, and fourth longitudinal beams are long truss beams;

[0020] The floor beam is located at the bottom center of the machine body and runs through the machine body frame in the middle of the machine body; the floor beam is machined into one piece.

[0021] Furthermore, the long truss beam comprises multiple sections, which are connected by long truss joints;

[0022] The cross-section of the long truss is Ω-shaped with the opening facing outwards; the outer layer of the Ω-shape is made of composite material, and the groove of the Ω-shape is filled with foam.

[0023] Another aspect of this utility model is to provide a cargo aircraft, including a main landing gear, a tail landing gear and the aforementioned aircraft fuselage structure;

[0024] The landing gear connecting bracket includes a main landing gear connecting bracket, and a first connector and a second connector are provided on the inner side of the main landing gear connecting bracket. The first connector and the second connector are connected to the main landing gear.

[0025] The fuselage structure has a side beam, and a third joint and a fourth joint are provided on the inner side of the side beam. The third joint and the fourth joint are connected to the tail landing gear.

[0026] Furthermore, it also includes the wings;

[0027] The fuselage frame includes a reinforcing frame, and the reinforcing frame includes a third reinforcing frame and a fourth reinforcing frame;

[0028] The third and fourth reinforcing frames are located at the junction of the fuselage and the wing, and wing joints and wing-body joints are provided on the third and fourth reinforcing frames; the wing is connected to the fuselage structure through the wing joints and wing-body joints.

[0029] Furthermore, it also includes a tail fin; the general frame further includes a fourth general frame and a fifth general frame;

[0030] The fourth and fifth ordinary frames are located at the junction of the fuselage structure and the tail fin. The fourth and fifth ordinary frames are provided with lugs, and the tail fin is connected to the fuselage structure through the lugs.

[0031] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0032] (1) In this utility model, the fuselage frame is the internal load-bearing structure of the fuselage. The fuselage frames are arranged side by side along the direction parallel to the length of the fuselage. The landing gear connecting bracket is integrally formed with the corresponding fuselage frame, which avoids stress concentration and complexity of additional structures in the traditional discrete component connection method, improves the overall structural strength of the fuselage, simplifies the assembly process, reduces the number of parts and the weight of the fuselage, thereby improving the load-bearing ratio.

[0033] (2) The fuselage frame includes a reinforced frame and a regular frame. The reinforced frame mainly bears high concentrated loads, while the regular frame mainly bears distributed loads.

[0034] The reinforced frame extension serves as an extension of the main load-bearing structure of the fuselage. The first landing gear support is located on the inner side of the extension, allowing the landing impact load borne by the landing gear to be directly transferred to the web and flanges of the reinforced frame through the support, avoiding stress concentration caused by the long cantilever effect of traditional outer supports. The ordinary bulkhead mainly bears the distributed load of the fuselage, while the tail landing gear load is transferred and diffused to the fuselage panels through the ordinary bulkhead and side beams.

[0035] (3) The yaw (X-direction) load of the main landing gear is diffused to the fuselage through the bulkhead and keel beam arranged on the fuselage; the lateral (Y-direction) load of the main landing gear is mainly transferred to the transverse ribs on the reinforcing bulkhead through the first joint for balance; the vertical (Z-direction) load of the main landing gear is mainly transferred to the main landing gear connecting bulkhead through the second joint for diffusion.

[0036] (4) The stringers are composed of composite materials and foam, located from the front of the middle fuselage to the rear fuselage, and are divided into multiple sections connected by stringer joints. The cross-section of the stringers is "Ω" shaped, with the outer layer made of composite materials and the grooves filled with foam, which has strong bending and tensile mechanical properties. After being bonded to the skin, it also has strong stability. It plays a role in resisting impact and drilling damage, improving damage tolerance, and ensuring safety. The intermediate floor beam is a machined one-piece beam with an I-shaped cross-section, which has good bending and shear resistance.

[0037] (5) The wing joint and wing-body joint are used to transmit the wing's directional (X-direction) load and vertical (Z-direction) load, as well as to balance the roll moment and pitch moment, and to transmit the wing's lateral (Y-direction) load and balance the yaw moment. The wing load is transmitted to the fuselage through the wing joint and wing-body joint located in the third and fourth reinforcing frames, and diffused onto the fuselage panels.

[0038] The lugs are used to transmit the yaw (X-axis) and vertical (Z-axis) loads of the tail fin, as well as to balance the roll and pitch moments, and to transmit the lateral (Y-axis) loads of the tail fin and balance the yaw moment. The tail fin loads are transmitted to the fuselage panels where the fuselage and tail fin are connected via the lugs located in the fourth and fifth common frames.

[0039] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages will become apparent from the description or be learned by practicing this invention. The objectives and other advantages of this invention can be realized and obtained from the details specifically pointed out in the text and accompanying drawings. Attached Figure Description

[0040] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0041] Figure 1 This is a schematic diagram of the fuselage structure of Example 1;

[0042] Figure 2 This is a cross-sectional schematic diagram of the fuselage structure of Example 1;

[0043] Figure 3 This is a schematic diagram of the stringer structure in Example 1;

[0044] Figure 4 This is a schematic diagram of the floor beam structure in Example 1;

[0045] Figure 5 This is a schematic diagram of the cross-section of the stringer in Example 1;

[0046] Figure 6 This is a schematic diagram of the long stringer joint in Example 1;

[0047] Figure 7 This is a schematic diagram of the skin structure of Example 1;

[0048] Figure 8 This is a schematic diagram of the fuselage frame structure in Example 1;

[0049] Figure 9 This is a schematic diagram of the connection structure between the fuselage bulkhead and the stringer joint in Example 1;

[0050] Figure 10 This is a schematic diagram of the reinforcing frame in Example 1;

[0051] Figure 11 This is a schematic diagram of the structure of a standard frame in Example 1;

[0052] Figure 12 This is a structural schematic diagram of the main cabin load-bearing structure in Example 1;

[0053] Figure 13 This is a schematic diagram of the keel beam structure in Example 1;

[0054] Figure 14 This is a structural schematic diagram of the stern compartment load-bearing structure in Example 1;

[0055] Figure label:

[0056] 1-Longitudinal beam; 11-First longitudinal beam; 12-Second longitudinal beam; 13-Third longitudinal beam; 14-Fourth longitudinal beam; 15-Stringer joint; 16-Floor beam; 2-Skin; 21-Nose cowl; 22-Mid-fuselage skin; 23-Left mid-fuselage skin; 24-Lower mid-fuselage skin; 25-Right mid-fuselage skin; 26-Rear fuselage skin; 27-Lower rear fuselage skin; 28-Tail cowl; 3-Main landing gear connecting bracket; 31-First joint; 32-Second joint; 4-Aircraft Body frame; 41-Reinforced frame; 411-First reinforced frame; 412-Second reinforced frame; 413-Third reinforced frame; 414-Fourth reinforced frame; 415-Fifth reinforced frame; 42-Ordinary frame; 421-First ordinary frame; 422-Second ordinary frame; 423-Third ordinary frame; 424-Fourth ordinary frame; 425-Fifth ordinary frame; 43-Corner plate; 5-Keel beam; 6-Short beam; 7-Edge beam; 71-Third joint; 72-Fourth joint; 8-Top plate. Detailed Implementation

[0057] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0058] Example 1

[0059] A specific embodiment of this utility model is as follows: Figure 1 and Figure 2 As shown, a fuselage structure is disclosed, including a longitudinal beam 1, a landing gear connecting bracket and a fuselage bulkhead 4;

[0060] Multiple fuselage frames 4 are arranged side by side along the length of the aircraft fuselage; multiple fuselage frames 4 are connected to the longitudinal beam 1, and at least one fuselage frame 4 is connected to the landing gear connecting bracket.

[0061] At least one fuselage frame 4 is integrally formed with the landing gear connecting bracket.

[0062] In this embodiment, the fuselage frame 4 is the internal load-bearing structure of the fuselage. The fuselage frames 4 are arranged side by side along the length direction parallel to the fuselage. The landing gear connecting bracket is integrally formed with the corresponding fuselage frame 4, which avoids stress concentration and design complexity of additional structures in the traditional discrete component connection method, improves the overall structural strength of the fuselage, simplifies the assembly process, reduces the number of parts and the weight of the fuselage, thereby improving the load-bearing ratio.

[0063] The longitudinal beam 1 includes a first longitudinal beam 11, a second longitudinal beam 12, a third longitudinal beam 13, and a fourth longitudinal beam 14 arranged from the front end of the middle fuselage to the rear end of the aft fuselage, as follows: Figure 3 As shown, the first longitudinal beam 11, the second longitudinal beam 12, the third longitudinal beam 13 and the fourth longitudinal beam 14 are long truss beams.

[0064] The stringer is a core component of the longitudinal load-bearing structure of an aircraft fuselage and wing, primarily bearing axial tensile and compressive loads, bending loads on the flanges, and shear loads on the webs. For example... Figure 5 As shown, the cross-section of the long truss is Ω-shaped with the opening facing outwards. The Ω shape is a semi-closed section with an opening on one side. The long truss has high torsional stiffness, which can effectively suppress the cross-sectional distortion of the long truss under torsional loads and avoid local skin instability caused by torsional deformation. At the same time, it is easy to assemble.

[0065] like Figure 5 As shown, the outer layer of the Ω-shaped long stringer is made of composite material, and the groove is filled with foam. Preferably, the long stringer is composed of carbon fiber / glass fiber resin-based composite material and PMI foam, which has strong bending and tensile mechanical properties. After being bonded to the skin 2, it also has strong stability, which can play a role in resisting impact and drilling damage, improving damage tolerance and enhancing the safety of the fuselage.

[0066] Due to the large length of the truss girder, to avoid difficulties in subsequent assembly, the truss girder is divided into multiple segments, which are connected by truss joints 15, such as... Figure 6 As shown, stringer joint 15 is Ω-shaped and is a machined metal part.

[0067] Furthermore, the longitudinal beam 1 also includes a floor beam 16. For example... Figure 1 As shown, the floor beam 16 is located at the bottom center of the fuselage and extends through the fuselage bulkhead 4 in the middle of the fuselage, specifically from the first bulkhead at the nose to the eleventh bulkhead of the fuselage. Figure 4 As shown, the floor beam 16 is a machined, one-piece formed beam with an I-shaped cross-section, exhibiting good bending and shear resistance. Exemplarily, the floor beam 16 is connected to the partition frame via corner pieces 43. The corner pieces 43 have an L-shaped structure and are located on the lower outer side of the first and eleventh partition frames. The connecting part of the floor beam 16 has a T-shaped structure, with the upper part of the T-shaped structure resting on the corner pieces 43 and connected to the L-shaped structure of the corner pieces 43 via bolts.

[0068] The longitudinal beam 1 and the skin 2 together form the external structure of the fuselage. For example... Figure 7 As shown, the skin 2 includes a nose cone 21, a mid-fuselage skin, a rear fuselage skin, and a tail cone 28.

[0069] For the sake of wave transmission, the head cover 21 is made of glass fiber resin-based composite material and PMI to form a foam sandwich structure, which has high rigidity and low cost.

[0070] The mid-fuselage skin includes the upper mid-fuselage skin 22, the left mid-fuselage skin 23, the lower mid-fuselage skin 24, and the right mid-fuselage skin 25. The mid-fuselage skin is the largest component on the fuselage. Considering high performance, low cost, and low weight, a sandwich structure is constructed using T700 medium-temperature curing unidirectional tape prepreg, T300 medium-temperature curing carbon fiber fabric prepreg, and high-density PMI foam. To reduce electrochemical corrosion between the carbon fiber skin stringer and the aluminum alloy frame, a 0.1mm thick layer of glass fiber fabric prepreg is added to the innermost layer, serving as an isolation and protection mechanism. During assembly, a waterproof primer is applied to the skin areas in contact with aluminum alloy parts to further reduce electrochemical corrosion.

[0071] The main loads on the upper fuselage skin 22 and the lower fuselage skin 24 are tension and compression, so the main material is T700 carbon fiber unidirectional tape, which fully utilizes its high specific strength in the 0° direction. The inner and outer surfaces are made of T300 carbon fiber fabric, which plays a role in resisting impact and drilling damage, and improving damage tolerance and safety.

[0072] The main functions of the left and right skins of the middle fuselage 23 and 25 are to transmit shear stress and resist potential losses caused by propeller ice ejection. They also have more openings than the upper and lower skins. Therefore, the main material is T300 carbon fiber fabric, laid in a quasi-isotropic ply, which has a high shear transmission capacity, impact resistance, and drill damage resistance, improving damage tolerance and ensuring safety.

[0073] The rear fuselage skin includes the upper rear fuselage skin 26 and the lower rear fuselage skin 27. The main loads on the upper rear fuselage skin 26 and the lower rear fuselage skin 27 are relatively complex. The tail cone area is small but the curvature of the shape is extremely large. Therefore, the main material is T300 carbon fiber fabric, laid in a quasi-isotropic ply, which has a high ability to cope with multi-directional loads and resistance to impact and drilling damage, thereby improving damage tolerance and safety.

[0074] The tail cover 28 is made of T300 carbon fiber woven fabric, and the inner surface is made of glass fiber woven fabric.

[0075] The landing gear connecting bracket includes a main landing gear connecting bracket 3, which is used to connect the main landing gear. The main landing gear connecting bracket 3 is provided with a first connector 31 and a second connector 32 for connecting the main landing gear. The first connector 31 and the second connector 32 are symmetrically arranged on the inner side of the main landing gear connecting bracket 3.

[0076] like Figure 8As shown, multiple fuselage bulkheads 4 are arranged side-by-side along a direction parallel to the longitudinal axis of the fuselage, from the nose to the tail. Exemplarily, in this embodiment, a total of 17 fuselage bulkheads 4 are provided, and the material of the fuselage bulkheads 4 is aviation aluminum alloy. Long stringer joints 15 are provided at the circumferential edge of the fuselage bulkheads 4, and long stringers are connected through long stringer joints 15. Exemplarily, as... Figure 9 As shown, two stringer joints 15 are provided on both sides of the fuselage frame 4, one for connecting the fuselage frame 4 and the other for connecting the stringer beam. The stringer joints 15 are riveted to the fuselage frame 4 and the stringer beam.

[0077] The fuselage frame 4 includes a standard frame 42 and a reinforcing frame 41. For example... Figure 10 As shown, the reinforcing frame 41 has an I-shaped cross-section and primarily bears high concentrated loads. It is located at the connection points between the fuselage and the main landing gear, wings, and tail. I-shaped beams possess strong bending and shear resistance. Figure 11 As shown, the ordinary frame 42 is a slotted machined frame, which mainly bears the distributed load and is distributed in other areas of the fuselage.

[0078] The reinforcing frame 41 includes a first reinforcing frame 411 and a second reinforcing frame 412. For example... Figure 8 As shown, the first reinforcing frame 411 and the second reinforcing frame 412 are located at the front end of the middle part of the fuselage. Figure 10 As shown, the first reinforcing frame 411 and the second reinforcing frame 412 include a frame body and a reinforcing structure disposed at the lower part of the frame body. The reinforcing structure extends into extensions on both sides of the frame body. The reinforcing structure of the first reinforcing frame 411 extends into first extensions on both sides of the frame body, and the reinforcing structure of the second reinforcing frame 412 extends into second extensions on both sides of the frame body. The main landing gear connecting bracket 3 includes a first part and a second part, which are respectively connected to the first extension and the second extension, and are symmetrically arranged on both sides of the center line of the first reinforcing frame 411 and the second reinforcing frame 412. The first part and the second part of the main landing gear connecting bracket 3 are integrally formed with the first reinforcing frame 411 and the second reinforcing frame 412, respectively. Further, a short beam 6 is provided at the end of the main landing gear connecting bracket 3, and the short beam 6 is used to connect the first part and the second part.

[0079] In this embodiment, the reinforcing frame 41 mainly bears high concentrated loads. The extension of the reinforcing frame 41 serves as an extension of the main load-bearing structure of the fuselage. The main landing gear connecting bracket 3 is connected to the extension of the first reinforcing frame 411 and the second reinforcing frame 412 and is integrally formed with the first reinforcing frame 411 and the second reinforcing frame 412. This allows the landing impact load borne by the main landing gear to be directly transferred to the web and flange of the reinforcing frame 41 through the main landing gear connecting bracket 3, avoiding stress concentration caused by the long cantilever effect of traditional outer supports.

[0080] like Figure 1As shown, the top of the reinforcing structure of the first reinforcing frame 411 and the second reinforcing frame 412 is provided with a top plate 8, as shown. Figure 12 As shown, keel beams 5 are vertically arranged on both sides of the top plate 8 between the reinforcing structures of the first reinforcing frame 411 and the second reinforcing frame 412. The keel beams 5 are perpendicular to and abut against the first reinforcing frame 411 and the second reinforcing frame 412 at both ends. The first reinforcing frame 411, the second reinforcing frame 412, the top plate 8, and the keel beams 5 together form the main cabin load-bearing structure 5. The top plate 8 and the keel beams 5 are the main cabin load-bearing components. Figure 13 As shown, the keel beam 5 has transverse and longitudinal reinforcing ribs.

[0081] The yaw (X-direction) load of the main landing gear is diffused to the fuselage through the first reinforcing frame 411, the second reinforcing frame 412 and the keel beam 5 arranged on the fuselage; the lateral (Y-direction) load of the main landing gear is mainly transferred to the transverse ribs on the first reinforcing frame 411 and the second reinforcing frame 412 through the first joint 31 for balance; the vertical (Z-direction) load of the main landing gear is mainly transferred to the main landing gear connecting bulkhead through the second joint 32 for diffusion.

[0082] The ordinary frame 42 includes a first ordinary frame 421, a second ordinary frame 422, and a third ordinary frame 423. The first ordinary frame 421, the second ordinary frame 422, and the third ordinary frame 423 are located at the rear end of the middle part of the fuselage.

[0083] Side beams 7 are symmetrically arranged at the lower parts of the first ordinary frame 421, the second ordinary frame 422, and the third ordinary frame 423. The first ordinary frame 421, the second ordinary frame 422, and the third ordinary frame 423, together with the side beams 7, form the stern compartment load-bearing structure. Figure 14 As shown. The third connector 71 and the fourth connector 72 are located on the inner side of the side beam 7 and are used to connect the tail landing gear. The third connector 71 is connected to the tail landing gear's tail landing gear's tail landing gear's tail landing gear's tail landing gear's tail landing gear's tail landing gear connecting rod. The ordinary frame 42 mainly bears the distributed load of the fuselage. The tail landing gear load is transmitted through the third connector 71 and the fourth connector 72 to the first ordinary frame 421, the second ordinary frame 422, the third ordinary frame 423, and the side beam 7, and is then distributed to the fuselage panels.

[0084] Example 2

[0085] This embodiment discloses an unmanned cargo carrier aircraft, including a main landing gear, a tail landing gear, and the fuselage structure of Embodiment 1.

[0086] The main landing gear connecting bracket 3 is provided with a first connector 31 and a second connector 32, which are connected to the main landing gear.

[0087] The inner side of the side beam 7 is provided with a third joint 71 and a fourth joint 72, which are connected to the tail landing gear.

[0088] like Figure 8 As shown, the reinforcing frame 41 of the fuselage bulkhead 4 also includes a third reinforcing frame 413 and a fourth reinforcing frame 414. The ordinary frame 42 also includes a fourth ordinary frame 424 and a fifth ordinary frame 425.

[0089] The third reinforcing frame 413, the fourth reinforcing frame 414, the fourth ordinary frame 424, and the fifth ordinary frame 425 are provided with connectors for connecting to the wings and tail.

[0090] The third reinforcing frame 413 and the fourth reinforcing frame 414 are the front and rear spar frames for the docking of the fuselage and the wing. The third reinforcing frame 413 and the fourth reinforcing frame 414 are equipped with wing joints and wing-body joints. The wing is connected to the fuselage structure through the wing joints and wing-body joints.

[0091] The fourth general frame 424 and the fifth general frame 425 are located at the junction of the fuselage structure and the tail fin. The fourth general frame 424 and the fifth general frame 425 are provided with lugs, and the tail fin is connected to the fuselage structure through the lugs.

[0092] In this embodiment, the wing joint and wing-body joint are used to transmit the wing's directional (X-axis) load and vertical (Z-axis) load, as well as balance the roll moment and pitch moment, and to transmit the wing's lateral (Y-axis) load and balance the yaw moment. The wing load is transmitted to the fuselage through the wing joint and wing-body joint located in the third reinforcing frame 413 and the fourth reinforcing frame 414, and then diffused onto the fuselage panels.

[0093] The lugs are used to transmit the yaw (X-axis) load and vertical (Z-axis) load of the tail fin, as well as to balance the roll and pitch moments, and to transmit the lateral (Y-axis) load of the tail fin and balance the yaw moment. The tail fin load is transmitted to the fuselage panel where the fuselage and tail fin are connected via the lugs located in the fourth general frame 424 and the fifth general frame 425.

[0094] Furthermore, the reinforcing frame 41 also includes a fifth reinforcing frame 415. The fifth reinforcing frame 415 is located between the tail landing gear and the tail fin. It is an important frame connecting the rear of the fuselage and the middle of the fuselage. At the same time, it serves as the lap boundary of the stringer, with stringer joints 15 connected to both sides to transfer the load generated by the tail fin.

[0095] Furthermore, it also includes avionics systems, which are partitioned within the fuselage.

[0096] A zoned layout design for avionics systems can effectively reduce the structural weight of the aircraft, increase the aircraft's payload ratio, and improve system maintainability.

[0097] The above are merely preferred embodiments of this utility model, but the scope of protection of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the scope of protection of this utility model.

Claims

1. An aircraft fuselage structure, characterized in that, Including longitudinal beams (1), landing gear connecting brackets and fuselage bulkheads (4); Multiple fuselage frames (4) are arranged side by side along the length of the aircraft fuselage; multiple fuselage frames (4) are connected to each other by the longitudinal beam (1); at least one fuselage frame (4) is connected to the landing gear connecting bracket, and at least one fuselage frame (4) and the landing gear connecting bracket are integrally formed.

2. The aircraft fuselage structure according to claim 1, characterized in that, The fuselage frame (4) includes a reinforcing frame (41), the cross-section of which is I-shaped; The reinforcing frame (41) includes a first reinforcing frame (411) and a second reinforcing frame (412). The first reinforcing frame (411) and the second reinforcing frame (412) are disposed at the front end of the middle part of the fuselage. The first reinforcing frame (411) and the second reinforcing frame (412) are connected to the landing gear connecting bracket.

3. The aircraft fuselage structure according to claim 2, characterized in that, The first reinforcing frame (411) and the second reinforcing frame (412) include a frame body and a reinforcing structure disposed at the lower part of the frame body; the reinforcing structure of the first reinforcing frame (411) extends into a first extension portion to both sides of its frame body, and the reinforcing structure of the second reinforcing frame (412) extends into a second extension portion to both sides of its frame body.

4. The aircraft fuselage structure according to claim 3, characterized in that, The landing gear connecting bracket includes a main landing gear connecting bracket (3), which includes a first part and a second part. The first part is symmetrically arranged on both sides of the first reinforcing frame (411), and the second part is symmetrically arranged on both sides of the second reinforcing frame (412). The first part is connected to the first extension, and the second part is connected to the second extension. The first part is integrally formed with the first reinforcing frame (411), and the second part is integrally formed with the second reinforcing frame (412).

5. The aircraft fuselage structure according to claim 3, characterized in that, The top of the reinforcing structure of the first reinforcing frame (411) and the reinforcing structure of the second reinforcing frame (412) is provided with a top plate (8), and a keel beam (5) is provided between the reinforcing structure of the first reinforcing frame (411) and the reinforcing structure of the second reinforcing frame (412). The two ends of the keel beam (5) are perpendicular and abut against the first reinforcing frame (411) and the second reinforcing frame (412). The first reinforcing frame (411), the second reinforcing frame (412), the top plate (8), and the keel beam (5) together constitute the load-bearing structure of the main cabin of the aircraft.

6. The aircraft fuselage structure according to claim 1, characterized in that, The fuselage frame (4) also includes a regular frame (42), the cross-section of which is groove-shaped; The ordinary frame (42) includes a first ordinary frame (421), a second ordinary frame (422), and a third ordinary frame (423); the first ordinary frame (421), the second ordinary frame (422), and the third ordinary frame (423) are located at the rear end of the middle part of the fuselage.

7. The aircraft fuselage structure according to claim 6, characterized in that, Side beams (7) are provided at the lower part of the first ordinary frame (421), the second ordinary frame (422) and the third ordinary frame (423); the side beams (7) are symmetrically arranged on both sides of the second ordinary frame (422); the side beams (7) are used to connect the tail landing gear; The first ordinary frame (421), the second ordinary frame (422), the third ordinary frame (423), and the side beam (7) together constitute the load-bearing structure of the aircraft's tail compartment.

8. The aircraft fuselage structure according to claim 1, characterized in that, The longitudinal beam (1) includes a first longitudinal beam (11), a second longitudinal beam (12), a third longitudinal beam (13), a fourth longitudinal beam (14), and a floor beam (16) arranged from the front end of the middle of the fuselage to the rear end of the fuselage; The first longitudinal beam (11), the second longitudinal beam (12), the third longitudinal beam (13) and the fourth longitudinal beam (14) are long truss beams; The floor beam (16) is located at the bottom center of the fuselage and passes through the fuselage partition (4) in the middle of the fuselage.

9. The aircraft fuselage structure according to claim 8, characterized in that, The long truss beam comprises multiple sections, which are connected by long truss joints (15); The cross-section of the long truss is Ω-shaped with the opening facing outwards; the outer layer of the Ω-shape is made of composite material, and the groove of the Ω-shape is filled with foam.

10. A cargo-carrying aircraft, characterized in that, Includes the main landing gear, the tail landing gear, and the aircraft fuselage structure as described in any one of claims 1-9; The landing gear connecting bracket includes a main landing gear connecting bracket (3); the main landing gear connecting bracket (3) is provided with a first connector (31) and a second connector (32) on its inner side, and the first connector (31) and the second connector (32) are connected to the main landing gear; The fuselage structure has a side beam (7), and a third joint (71) and a fourth joint (72) are provided on the inner side of the side beam (7). The third joint (71) and the fourth joint (72) are connected to the tail landing gear.

11. The cargo-carrying aircraft according to claim 10, characterized in that, It also includes the wings; The fuselage frame (4) includes a reinforcing frame (41), and the reinforcing frame (41) includes a third reinforcing frame (413) and a fourth reinforcing frame (414); The third reinforcing frame (413) and the fourth reinforcing frame (414) are located at the junction of the fuselage structure and the wing. The third reinforcing frame (413) and the fourth reinforcing frame (414) are provided with wing joints and wing-body joints. The wing is connected to the fuselage structure through the wing joints and the wing-body joints.

12. The cargo-carrying aircraft according to claim 11, characterized in that, It also includes a tail fin; the ordinary frame (42) further includes a fourth ordinary frame (424) and a fifth ordinary frame (425); The fourth ordinary frame (424) and the fifth ordinary frame (425) are located at the junction of the fuselage structure and the tail fin. The fourth ordinary frame (424) and the fifth ordinary frame (425) are provided with lugs, and the tail fin is connected to the fuselage structure through the lugs.

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