An aircraft and an aft fuselage structure therefor

Abstract

The application discloses an airplane and a rear fuselage structure thereof, which is a structure capable of transferring out-of-plane bending moment of a reinforcing frame at a large opening of the airplane, all parts of which are integrally machined from 7050-T7451 aluminum alloy, and the process is mature; the crossbeam in the structure can bear the out-of-plane bending moment of the reinforcing frame, the rest parts can transfer the longitudinal load of the fuselage, and the structure can meet the requirement of opening a large cover on the fuselage. Meanwhile, the structure has strong load transfer capacity, light structure weight, simple assembly, corrosion resistance, and uses common standard parts, and has good processability and feasibility.

Description

Technical Field

[0001] This invention relates to the field of aircraft technology, and in particular to an aircraft and its rear fuselage structure. Background Technology

[0002] The aft fuselage structure, located at the rearmost end of the fuselage structure, is typically a semi-monocoque structure composed of transverse bulkheads, longitudinal stringers or beams, and their skin. Retractable landing gear and engines are usually housed in the aft fuselage, necessitating the design of large openings in the aft fuselage structure for landing gear retraction and engine maintenance.

[0003] Large openings in an aircraft structure can affect its stiffness, strength, and load transfer. The aircraft fuselage structure primarily transfers loads through transverse and longitudinal frames. The transverse frames are stiffening frames, and the longitudinal frames are main beams. Stiffening frames can only withstand in-plane loads, not out-of-plane loads; therefore, the main beams that transfer longitudinal loads need to be continuous at the stiffening frames.

[0004] However, in areas where large openings are required, the continuity of the main beam cannot be guaranteed. This necessitates the design of a structure that can transfer the external load of the reinforced frame at the large opening. Summary of the Invention

[0005] In view of this, the present invention provides an aircraft and its rear fuselage structure that solves the problem that the reinforcing frame cannot transmit out-of-plane bending moments at large openings in the aircraft structure.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A rear fuselage structure includes: a crossbeam, a reinforcing frame, a left rear beam, a right rear beam, and a front beam;

[0008] The reinforcing frame is connected to the left rear beam and the right rear beam respectively, the crossbeam is connected to the reinforcing frame, and the crossbeam is connected to the front beam.

[0009] Preferably, the crossbeam is a hollow structure capable of withstanding bending moments.

[0010] Preferably, both ends of the crossbeam are connected to the web of the reinforcing frame.

[0011] Preferably, the inner web plates at both ends of the crossbeam are bolted to the web plates of the reinforcing frame.

[0012] Preferably, the middle section of the crossbeam is connected to the rear section of the front beam.

[0013] Preferably, the web of the middle section of the crossbeam is bolted to the rear web of the front beam.

[0014] Preferably, the outer webs at both ends of the crossbeam are bolted to the front ends of the left rear beam and the right rear beam, respectively.

[0015] Preferably, stiffeners are provided between the front and rear webs of the crossbeam.

[0016] Preferably, it further includes: a front skin;

[0017] The front skin is connected to the outer edge strip of the crossbeam, and the front skin is connected to the front edge strip of the reinforcing frame.

[0018] An aircraft comprising the rear fuselage structure as described above.

[0019] As can be seen from the above technical solution, the present invention provides an aircraft and its rear fuselage structure, which is a structural form that can transmit the external bending moment of the reinforcing frame at the large opening of the aircraft. It includes a crossbeam, a reinforcing frame, a left rear beam, a right rear beam, a left rear skin, a right rear skin, a front beam, a front skin, a maintenance cover, and multiple connecting bolts, rivets, and studs.

[0020] The front beam and front skin are located in front of the reinforcing frame and at the bottom of the main landing gear bay. In order to allow the main landing gear to retract and extend, a large enough space needs to be left on both sides of the main landing gear bay, thus forming a large opening structure.

[0021] The left rear beam, right rear beam, left rear skin, right rear skin, and maintenance hatch are located behind the reinforcing frame. The left rear beam, right rear beam, left rear skin, and right rear skin are located on both sides of this compartment, and the maintenance hatch is located below this compartment. The maintenance hatch provides a passage for the routine maintenance of the engine and its accessories, thus forming a large opening structure.

[0022] The longitudinal loads transmitted from the engine to the left and right rear beams cannot be directly transmitted to the front beam after being transferred to the reinforcing frame. A crossbeam needs to be added between the reinforcing frame and the front beam. The crossbeam can transfer the longitudinal loads from the left and right rear beams to the front beam, thus realizing the transfer of longitudinal loads at the reinforcing frame.

[0023] This invention relates to a structure capable of transmitting out-of-plane bending moments of a reinforcing frame at large openings in aircraft. All parts are integrally machined from 7050-T7451 aluminum alloy, a mature manufacturing process. The crossbeams in this structure can withstand out-of-plane bending moments at the reinforcing frame, while the remaining parts can transmit longitudinal loads from the fuselage. Furthermore, this structure can meet the requirements for large openings on the fuselage. Simultaneously, this structure boasts strong load-bearing capacity, lightweight construction, simple assembly, corrosion resistance, and utilizes commonly used standard parts, demonstrating good manufacturability and feasibility. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This invention relates to a structural component that can transmit the external bending moment of a reinforcing frame at a large opening in an aircraft.

[0026] Figure 2 This invention provides a structural frame structure that can transmit the external bending moment of the reinforcing frame at large openings in aircraft.

[0027] Figure 3 This refers to the specific structural form of the crossbeam in this invention;

[0028] Figure 4 This is a schematic diagram of the bolt hole structure of the entire crossbeam of the present invention;

[0029] Figure 5 This is a schematic diagram of the bolt connection structure on the left side of the crossbeam of the present invention;

[0030] Figure 6 This is a schematic diagram of the bolt connection structure of the middle section of the crossbeam of the present invention;

[0031] Figure 7 This is a schematic diagram of the bolted connection structure between the left rear beam and the reinforcing frame ribs of the present invention.

[0032] Among them, 1-crossbeam, 2-reinforcing frame, 3-left rear beam, 4-right rear beam, 5-left rear skin, 6-right rear skin, 7-front beam, 8-front skin, 9-maintenance cover. Detailed Implementation

[0033] To address the issue of large openings at the reinforcing frame in aircraft structures, this application proposes a structure that can transmit the out-of-plane bending moment of the reinforcing frame at the large opening, thereby both enabling the transfer of out-of-plane loads at the reinforcing frame and allowing the placement of a large cover at the reinforcing frame to meet overall requirements.

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] The rear fuselage structure provided in this embodiment of the invention includes: a crossbeam 1, a reinforcing frame 2, a left rear beam 3, a right rear beam 4, and a front beam 7, the structure of which can be referred to Figure 1 and Figure 2 As shown;

[0036] Among them, the reinforcing frame 2 is connected to the left rear beam 3 and the right rear beam 4 respectively, the crossbeam 1 is connected to the reinforcing frame 2, and the crossbeam 1 is connected to the front beam 7.

[0037] The load transfer path of this scheme is as follows: the longitudinal load is transferred to the reinforcing frame 2 through the left rear beam 3 and the right rear beam 4. The reinforcing frame 2 then transfers the longitudinal load to the crossbeam 1, and the crossbeam 1 then transfers the longitudinal load to the front beam 7. This completes the transfer of the longitudinal load at the reinforcing frame 2.

[0038] Furthermore, the crossbeam 1 is a key load-bearing component in this structure. It is a hollow structure that can withstand bending moments, in order to better solve the problem that the reinforcing frame cannot transmit out-of-plane bending moments at large openings in the aircraft structure.

[0039] Preferably, the two ends of the crossbeam 1 are connected to the web of the reinforcing frame 2 to optimize the load transfer path and facilitate the transfer of longitudinal loads from the left and right sides.

[0040] Specifically, the inner web plates 102 at both ends of the crossbeam 1 are bolted to the web plates of the reinforcing frame 2, and their structure can be referred to Figure 3 and Figure 4 As shown. In this embodiment, the inner web plates 102 at both ends of the crossbeam are connected to the web plate of the reinforcing frame 2 using 12 high-strength bolts, as shown. Figure 5 Bolts 1-6 (left side only).

[0041] Preferably, the middle section of the crossbeam 1 is connected to the rear section of the front beam 7, which facilitates the collection of longitudinal loads from both sides to the centrally located front beam 7.

[0042] Specifically, the middle section web 103 of the crossbeam 1 is bolted to the rear end web of the front beam 7, and its structure can be referred to Figure 3 and Figure 4 As shown. In this embodiment, the rear web of the front main beam 7 is connected to the middle web 103 of the crossbeam by 15 high-strength bolts, see... Figure 5 Bolt 1-15.

[0043] Furthermore, the left and right ends of the crossbeam 1 are respectively connected to the front ends of the left rear beam 3 and the right rear beam 4. Preferably, the connection is made by bolts, and its structure can be referenced. Figure 3 and Figure 4 As shown, the front ends of the left rear beam 3 and the right rear beam 4 are each connected to the outer web plates 101 at both ends of the crossbeam using 3 high-strength bolts.

[0044] Specifically, stiffeners 105 are provided between the front and rear webs of the crossbeam 1 to increase stability and load-bearing capacity.

[0045] The rear fuselage structure provided in this embodiment of the invention further includes: a front skin 8, the structure of which can be referred to Figure 1 As shown;

[0046] The front skin 8 and the outer edge strip 106 of the crossbeam 1 are connected, such as Figure 3 As shown; the front skin 8 and the front edge strip of the reinforcing frame 2 are connected.

[0047] This invention also provides an aircraft, including the rear fuselage structure as described above.

[0048] The following description, in conjunction with the accompanying drawings, details the manufacturing and assembly process and load transfer path of the reinforcing frame external bending moment transfer structure of the present invention at a large opening in an aircraft.

[0049] See Figure 1 The present invention is a structural form that can transmit the external bending moment of the reinforcing frame at the large opening of the aircraft, including a crossbeam 1, a reinforcing frame 2, a left rear beam 3, a right rear beam 4, a left rear skin 5, a right rear skin 6, a front beam 7, a front skin 8, a maintenance cover 9, and multiple connecting bolts, pull pins, support plate nuts and rivets.

[0050] In this structure, the two ends of the crossbeam 1 are connected to the web of the reinforcing frame 2, the middle section of the crossbeam 1 is connected to the rear section of the front main beam 57, and the left rear main beam 3 and right rear main beam 4 are connected to the reinforcing frame 2, thus forming a skeleton assembly. The front skin 8 is connected to the crossbeam 1, the front edge strip of the reinforcing frame 2, and the front main beam 7, while the left rear skin 5 and right rear skin 6 are connected to the rear edge strip of the reinforcing frame 2, the left rear main beam 3, and the right rear main beam 4, thus forming a non-removable structure. The maintenance cover 9 is connected to the rear edge strip of the reinforcing frame 2, the left rear main beam 3, and the right rear main beam 4, thus forming a removable maintenance cover.

[0051] All parts in this structure, except for maintenance cover 9, are integrally machined 7050-T7451 aluminum alloy parts. Maintenance cover 9 is a carbon fiber composite sandwich structure. For corrosion control, all aluminum alloy parts need to be chromate anodized and chromate sealed, and finally coated with TB06-9 strontium yellow primer.

[0052] The assembly method for this structure is as follows:

[0053] First, assemble the frame structure. Install the reinforcing frame 2 on the assembly jig, and then connect the inner web plates 102 at both ends of the crossbeam to the web plates of the reinforcing frame 2 using 12 high-strength bolts. Figure 5 Bolts 1-6 (left side only); then connect the rear web of the front main beam 7 to the middle web of the crossbeam 103 using 15 high-strength bolts, see... Figure 6Bolts 1-15; finally, connect the front ends of the left rear beam 3 and the right rear beam 4 to the web plate of the reinforcing frame 2 and the outer web plate 101 at both ends of the crossbeam using 3 high-strength bolts each, and connect the web plates of the left rear beam 3 and the right rear beam 4 to the stiffeners of the reinforcing frame 2 using 3 high-strength bolts each, see... Figure 6 Bolts 1-6 (left side only) indicate that the skeleton assembly is complete.

[0054] Then, skin panels are assembled on top of the frame components to form a non-removable structure. The front skin 8 is connected to the front edge strip of the reinforcing frame 2 by rivets. The front skin 8 is then connected to the outer edge strip of the crossbeam 106 by rivets. The front skin 8 is then connected to the front edge strip of the reinforcing frame 2 and the outer edge strip of the crossbeam 106 by eight high-strength bolts. Finally, the front skin 8 is connected to the front edge strip of the reinforcing frame 2 by pull studs. Next, the left rear skin 5 and the right rear skin 6 are connected to the rear edge strip of the reinforcing frame 2, the left rear beam 3, and the right rear beam 4 by rivets, thus forming a non-removable structure.

[0055] Finally, the maintenance cover 9 is assembled onto the non-removable structure to form an integral structure. The maintenance cover 9 is connected by the support plate nut, countersunk bolts, and the rear edge strip of the reinforcing frame 2, the left rear beam 3, and the right rear beam 4 to complete the assembly of the structure.

[0056] The load transfer path of a structure capable of transmitting the external bending moment of a reinforced frame at a large opening in an aircraft is as follows: The longitudinal load is transferred to the reinforced frame 2 via the left rear beam 3 and right rear beam 4. The reinforced frame 2 then transfers the longitudinal load to the crossbeam 1, which in turn transfers it to the front beam 7, thus completing the longitudinal load transfer at the reinforced frame 2. The crossbeam 1 is the key load-transfer component in this structure; it is a hollow structure capable of withstanding bending moments. The crossbeam 1 has bolt holes at both ends and in the middle. The ends connect to the web and flange of the reinforced frame 2, and the middle connects to the front beam 7. A total of 45 high-strength bolts are used. Figure 4 The crossbeam 1 can convert the longitudinal loads on both sides into bending moments and transfer them to the middle. The stiffeners 105 between the front and rear webs of the crossbeam increase stability and load transfer capacity. The web 104 of the crossbeam does not need to be connected to the web of the reinforcing frame 2, simplifying the connection method.

[0057] In summary, the purpose of this invention is to propose a structure that can transmit out-of-plane bending moments of a reinforcing frame at large openings in aircraft structures. This structure uses mature manufacturing processes and features lightweight, simple connection, easy assembly, and a reasonable force transmission path, thus solving the problem that the reinforcing frame cannot transmit out-of-plane bending moments at large openings in aircraft structures.

[0058] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0059] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A rear fuselage structure, characterized in that, include: Crossbeam (1), reinforcing frame (2), left rear beam (3), right rear beam (4) and front beam (7); The reinforcing frame (2) is connected to the left rear beam (3) and the right rear beam (4) respectively, the crossbeam (1) is connected to the reinforcing frame (2), and the crossbeam (1) is connected to the front beam (7); The beam (1) is a hollow structure capable of withstanding bending moments; The two ends of the crossbeam (1) are connected to the web of the reinforcing frame (2); The inner web plates (102) at both ends of the crossbeam (1) are bolted to the web plate of the reinforcing frame (2); The middle section of the crossbeam (1) is connected to the rear section of the front beam (7).

2. The rear fuselage structure according to claim 1, characterized in that, The middle section web (103) of the crossbeam (1) is bolted to the rear end web of the front beam (7).

3. The rear fuselage structure according to claim 1, characterized in that, The outer web plates (101) at both ends of the crossbeam (1) are respectively bolted to the front ends of the left rear beam (3) and the right rear beam (4).

4. The rear fuselage structure according to claim 1, characterized in that, The crossbeam (1) has reinforcing bars (105) between its front and rear webs.

5. The rear fuselage structure according to claim 1, characterized in that, Also includes: Front skin (8); The front skin (8) is connected to the outer edge strip (106) of the crossbeam (1), and the front skin (8) is connected to the front edge strip of the reinforcing frame (2).

6. An aircraft, characterized in that, Includes the rear fuselage structure as described in any one of claims 1-5.

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