Aircraft engine nacelle

Abstract

The utility model discloses an engine nacelle, which is applied to the field of aircraft manufacturing, is used for improving the structural strength of an aircraft engine nacelle, and comprises a front firewall, a rear firewall, an upper firewall, a front section skin, a middle section skin, a rear section skin and a mounting frame, a second through hole is formed in the rear firewall; the upper firewall is arranged between the front firewall and the rear firewall, the front end of the upper firewall is connected with the front firewall, the rear end of the upper firewall is connected with the rear firewall, the mounting frame and the U-shaped reinforcing beam are both of a U-shaped structure and are both located on the front side of the front firewall, and the mounting frame is arranged above the U-shaped reinforcing beam; the rear end of a front-section lower wall plate of the front-section skin is connected with the U-shaped reinforcing beam; the front ends of a middle-section left wall plate, a middle-section right wall plate and a middle-section upper wall plate of the middle-section skin are connected with the mounting frame; and the outer sides of the upper firewall, the front firewall and the rear firewall are coated with the middle-section skin.

Description

Technical Field

[0001] The utility model belongs to the technical field of aircraft manufacturing, and relates to an aircraft engine nacelle. Background Art

[0002] The aircraft engine nacelle is a key component in the aircraft structure. It not only protects the engine from the external environment but also undertakes the important task of transmitting the power generated by the engine to the aircraft. The structural design of the nacelle has a crucial impact on the performance, safety, and maintenance cost of the aircraft. With the continuous improvement of aircraft performance, the requirements for the structural strength of the nacelle are also getting higher and higher. In the prior art, to ensure the structural strength of the nacelle skin and the firewall, the skin and the firewall are usually connected by rivets, and the connection between each section of the skin is also connected by riveting, resulting in an excessively large overall weight of the nacelle structure. Content of the Utility Model

[0003] In view of this, the utility model discloses an aircraft engine nacelle, and the specific scheme is as follows:

[0004] An engine nacelle includes a front firewall, an upper firewall, a rear firewall, a front section skin, a middle section skin, a rear section skin, and a mounting frame;

[0005] The front firewall and the rear firewall are arranged relatively parallel. The front firewall is provided with a first through hole, and the rear firewall is provided with a second through hole; the upper firewall is arranged between the front firewall and the rear firewall, and the front end of the upper firewall is connected to the front firewall, and the rear end is connected to the rear firewall;

[0006] The mounting frame is a U-shaped structure with an opening downward, located on the front side of the front firewall and connected to the front firewall;

[0007] The front skin includes a front upper wall panel, an inlet lip, a front lower wall panel, and a U-shaped reinforcing beam. The U-shaped reinforcing beam is a U-shaped beam with an upward opening. The left free end of the mounting frame is connected to the left free end of the U-shaped reinforcing beam, and the right free end of the mounting frame is connected to the right free end of the U-shaped reinforcing beam. The front upper wall panel is located above the inlet lip and the front lower wall panel. The inlet lip is located in front of the front lower wall panel. The upper ends of the inlet lip and the front lower wall panel are both connected to the lower end of the front upper wall panel. The front end of the front lower wall panel is connected to the rear end of the inlet lip. The rear end of the front upper wall panel is connected to the mounting frame, and the rear end of the front lower wall panel is connected to the U-shaped reinforcing beam. The middle skin includes a middle upper wall panel, a middle left wall panel, a middle right wall panel, a left cabin door panel, and a right cabin door panel. The right end of the middle left wall panel is connected to the left end of the middle upper wall panel. The left end of the middle right wall panel is connected to the right end of the middle upper wall panel. The front ends of the middle left wall panel, the middle right wall panel, and the middle upper wall panel are all connected to the mounting frame. The rear end of the middle upper wall panel is connected to the front firewall. The rear ends of the middle left wall panel and the middle right wall panel are connected to the rear firewall. The inner surface of the middle left wall panel abuts against the left ends of the front firewall and the upper firewall. The inner surface of the middle right wall panel abuts against the right ends of the front firewall and the upper firewall. The upper end of the left cabin door panel is connected to the lower end of the middle left wall panel through a hinge. The upper end of the right cabin door panel is connected to the lower end of the middle right wall panel through a hinge. The rear skin is arranged at the rear side of the middle skin, and the front end of the rear skin is connected to the rear firewall.

[0008] As a supplement to the technical solution of the present invention, the front firewall includes an upper fireproof board, a lower fireproof board, side reinforcing ribs, a first arc-shaped reinforcing rib, and a second arc-shaped reinforcing rib. Semi-circular notches are provided in the lower part of the upper fireproof board and the upper part of the lower fireproof board. The lower end of the upper fireproof board is connected to the upper end of the lower fireproof board. The semi-circular notches of the upper fireproof board and the lower fireproof board form a first through hole.

[0009] A convex portion is provided at the lower end of the upper fireproof board. The convex portion is a plate-like structure extending downward at the lower end position of the upper fireproof board. The convex portion of the upper fireproof board is located at the rear side of the lower fireproof board, and the convex portion of the upper fireproof board is connected to the lower fireproof board.

[0010] The first arc-shaped reinforcing rib is arranged at the circumferential position of the lower semi-circular notch of the upper fireproof board. The second arc-shaped reinforcing rib is arranged at the circumferential position of the upper semi-circular notch of the lower fireproof board.

[0011] The side reinforcing ribs are arranged on the surface of the upper fireproof board. There are two groups of side reinforcing ribs. The first side reinforcing rib is arranged on the left part of the upper fireproof board, and the second side reinforcing rib is arranged on the right part of the upper fireproof board. Flanges are provided at the side edges of the first side reinforcing rib and the second side reinforcing rib. The first side reinforcing rib abuts against the middle left wall panel of the middle skin through its flange, and the second side reinforcing rib abuts against the middle right wall panel of the middle skin through its flange.

[0012] As a supplement to the technical solution of the present utility model, it further includes a reinforcing connecting rod, an eighth joint, a ninth joint, and a third reinforcing beam.

[0013] The front end of the reinforcing connecting rod is connected to the front firewall, and the rear end of the reinforcing connecting rod is connected to the rear firewall. There are two groups of the reinforcing connecting rods in total. The position where the first reinforcing connecting rod is connected to the front firewall is on the left side of the first through hole, and the position where the first reinforcing connecting rod is connected to the rear firewall is on the left side of the second through hole. The position where the second reinforcing connecting rod is connected to the front firewall is on the right side of the first through hole, and the position where the second reinforcing connecting rod is connected to the rear firewall is on the right side of the second through hole.

[0014] The front ends of the two reinforcing connecting rods are both connected to the front firewall through the eighth joint, and the rear ends of the two reinforcing connecting rods are both connected to the rear firewall through the ninth joint. The reinforcing connecting rod is hingedly connected to the eighth joint and the ninth joint. A third reinforcing beam is provided between the ninth joints at the rear ends of the two reinforcing connecting rods.

[0015] As a supplement to the technical solution of the present utility model, the upper firewall includes an upper fireproof board, an angle beam, a U-shaped beam, and an engine rear suspension point mounting box. Both the left and right ends of the upper fireproof board are provided with flanges. The left end of the upper fireproof board is connected to the middle left wall board of the middle section skin, and the right end of the upper fireproof board is connected to the middle right wall board of the upper firewall. The angle beam is an L-shaped long beam with a cross-section composed of two mutually perpendicular plate surfaces. The horizontal plate surface of the angle beam is riveted to the upper fireproof board, and the vertical plate surface of the angle beam is connected to the front firewall. The U-shaped beam includes a top plate surface, a bottom plate surface, and a web. The top plate surface and the bottom plate surface are connected by a vertically arranged web. The bottom plate surface of the U-shaped beam is connected to the upper firewall, and the web is connected to the rear firewall. A vertically opened through hole is provided on the upper fireproof board. The lower bottom surface of the engine rear suspension point mounting box is provided with a groove. The engine rear suspension point mounting box is located above the through hole on the upper fireproof board, and the lower end of the engine rear suspension point mounting box is connected to the upper fireproof board. The position where the engine rear suspension point mounting box is connected to the upper fireproof board is on the outer periphery of the through hole on the upper fireproof board, so that the through hole on the upper fireproof board is communicated with the inner space of the groove of the engine rear suspension point mounting box.

[0016] As a supplement to the technical solution of the present utility model, the front section skin further includes an elastic sealing strip. The air intake duct lip includes a lip skin, a web member, and a first U-shaped frame. The web member is riveted to the inner side of the lip skin and is located at the rear of the lip skin. A plate-shaped flange is provided on the side of the web member close to the lip skin. The plate-shaped flange is connected to the lip skin through a quick-release lock. The first U-shaped frame is arranged on the web member and there is a spacing between the first U-shaped frame and the plate-shaped flange on the web member.

[0017] The front lower wall panel includes a front lower wall panel skin and a second U-shaped frame. The second U-shaped frame is riveted to the front end of the front lower wall panel skin. The front end face of the second U-shaped frame is a flat plate surface, and the width of the front end face of the second U-shaped frame is greater than the distance between the first U-shaped frame and the plate-shaped flange. The second U-shaped frame abuts against the plate-shaped flange on the web member and the first U-shaped frame.

[0018] The second U-shaped frame, the web member, the plate-shaped flange, and the first U-shaped frame enclose a U-shaped belt-shaped space with a rectangular cross-section. The elastic sealing strip is arranged in the U-shaped belt-shaped space. The second U-shaped frame squeezes the elastic sealing strip, causing the elastic sealing strip to undergo compressive deformation to fill the U-shaped belt-shaped space.

[0019] As a supplement to the technical solution of the present utility model, the front upper wall panel includes a front upper wall panel skin and an upper wall panel reinforcing rib. The upper wall panel reinforcing rib is arranged inside the upper wall panel and is riveted to the front upper wall panel skin.

[0020] The air inlet lip further includes a first connecting backing plate. The lower part of the first connecting backing plate is located inside the lip skin and is connected to the lip skin. The upper part of the first connecting backing plate protrudes above the upper edge of the lip skin and is located inside the front upper wall panel skin. The upper part of the first connecting backing plate is connected to the front upper wall panel skin through a quick-release lock.

[0021] The front lower wall panel further includes a second connecting backing plate. The lower part of the second connecting backing plate is located inside the front lower wall panel skin and is connected to the front lower wall panel skin. The upper part of the second connecting backing plate protrudes above the upper edge of the front lower wall panel skin and is located inside the front upper wall panel skin. The second connecting backing plate is connected to the front upper wall panel skin through a quick-release lock.

[0022] As a supplement to the technical solution of the present utility model, the middle section skin further includes a tail cross beam and a mounting beam.

[0023] The left middle wall panel includes a left middle wall panel skin and a first connecting plate. The first connecting plate is arranged on the lower surface of the left middle wall panel skin through rivets, and the right part of the first connecting plate protrudes from the right end of the left middle wall panel skin and extends below the middle upper wall panel skin and is connected to the middle upper wall panel skin through a quick-release lock.

[0024] The right middle wall panel includes a right middle wall panel skin and a second connecting plate. The second connecting plate is arranged on the lower surface of the right middle wall panel skin through rivets, and the left part of the second connecting plate protrudes from the left end of the right middle wall panel skin and extends below the middle upper wall panel skin and is connected to the middle upper wall panel skin through a quick-release lock.

[0025] The installation beam is arranged on the installation frame and is located below the middle upper wall panel skin, the middle left wall panel skin, and the middle right wall panel skin. The front ends of the middle upper wall panel skin, the middle left wall panel skin, and the middle right wall panel skin are all connected to the installation beam through quick-release locks; the tail cross beam is riveted to the front firewall, and the rear end of the middle upper wall panel is connected to the tail cross beam through a quick-release lock.

[0026] As a supplement to the technical solution of the present utility model, the middle upper wall panel further includes upper wall panel longitudinal beams and upper wall panel cross beams. There are three groups of upper wall panel longitudinal beams, namely the first longitudinal beam, the second longitudinal beam, and the third longitudinal beam. The three groups of upper wall panel longitudinal beams are arranged in sequence from left to right on the lower bottom surface of the middle upper wall panel skin and are all connected to the middle upper wall panel skin through rivets;

[0027] The upper wall panel cross beams include a first short beam and a second short beam. The left end of the first short beam is connected to the first longitudinal beam, and the right end of the first short beam is connected to the second longitudinal beam; the left end of the second short beam is connected to the second longitudinal beam, and the right end of the second short beam is connected to the third longitudinal beam.

[0028] As a supplement to the technical solution of the present utility model, it further includes a tie rod system. The tie rod system includes a first joint, a second joint, a third joint, a fourth joint, a fifth joint, a sixth joint, a seventh joint, a left suspension point lower tie rod, a left suspension point upper tie rod, an upper suspension point left tie rod, an upper suspension point right tie rod, a right suspension point lower tie rod, and a right suspension point upper tie rod;

[0029] Among them, the first joint, the second joint, and the third joint are arranged on the installation frame, and the first joint is located at the left end of the installation frame, the second joint is located at the upper end of the installation frame, and the third joint is located at the right end of the installation frame;

[0030] The fourth joint, the fifth joint, the sixth joint, and the seventh joint are arranged on the front firewall. The fourth joint is located directly behind the first joint, the fifth joint is located directly above the fourth joint, the seventh joint is located directly behind the third joint, the sixth joint is located directly above the seventh joint, the sixth joint is located to the right of the fifth joint, and the sixth joint and the fifth joint are at the same horizontal height;

[0031] A left suspension point lower tie rod is connected between the first joint and the fourth joint, and a left suspension point upper tie rod is connected between the first joint and the fifth joint; an upper suspension point left tie rod is connected between the second joint and the fifth joint, and an upper suspension point right tie rod is connected between the second joint and the sixth joint; a right suspension point upper tie rod is connected between the third joint and the sixth joint, and a right suspension point lower tie rod is connected between the third joint and the seventh joint.

[0032] As a supplement to the technical solution of the present utility model, the tie rod system further includes a first firewall reinforcing beam, a second firewall reinforcing beam, and a third firewall reinforcing beam. The upper end of the first firewall reinforcing beam is connected to the fifth joint, and the lower end of the first firewall reinforcing beam is connected to the fourth joint; the upper end of the second firewall reinforcing beam is connected to the sixth joint, and the lower end of the second firewall reinforcing beam is connected to the seventh joint;

[0033] The third firewall reinforcing beam is disposed on the rear side surface of the front firewall. The left end of the third firewall reinforcing beam is connected to the fifth joint, and the right end is connected to the sixth joint.

[0034] Beneficial effects: The engine nacelle disclosed in the present utility model realizes the replacement of the rivet connection structure between the traditional middle section skin, the upper firewall and the front firewall, and can ensure the connection stability between the front section skin, the middle section skin, the rear section skin, the engine, the front firewall, the upper firewall and the rear firewall. While ensuring the overall structural strength, the number of connecting parts such as rivets is reduced, and the overall weight of the engine nacelle is reduced. In another aspect of the present utility model, it is realized that the front upper wall panel and the front lower wall panel can ensure the structural strength of the front section skin of the engine nacelle without using rigid connection, and at the same time ensure the sealing performance between the intake lip and the front lower wall panel, improving the assembly efficiency. In another aspect of the present utility model, by designing the middle upper wall panel, the middle left wall panel and the middle right wall panel in the middle section skin of the aircraft engine nacelle as detachable connections, when the engine is overhauled, only the quick-release lock for installing the upper wall panel skin needs to be disassembled to remove the middle upper wall panel, improving the work efficiency. Description of the Drawings

[0035] Figure 1 It is a three-dimensional structural schematic diagram of the present utility model.

[0036] Figure 2 It is an assembly structural schematic diagram of the front firewall, the upper firewall and the rear firewall.

[0037] Figure 3 It is an assembly structural schematic diagram of the front firewall, the upper firewall and the rear firewall.

[0038] Figure 4 It is a structural schematic diagram of the front firewall.

[0039] Figure 5 It is a structural schematic diagram of the upper firewall.

[0040] Figure 6 It is an assembly structural schematic diagram of the rear firewall.

[0041] Figure 7 It is a structural schematic diagram of the front section skin.

[0042] Figure 8 It is a structural schematic diagram of the front lower wall panel.

[0043] Figure 9 It is a schematic diagram of the front lower wall panel structure.

[0044] Figure 10 It is a schematic diagram of the inlet lip structure.

[0045] Figure 11 It is Figure 10 An enlarged schematic diagram of the structure at point A in

[0046] Figure 12 It is a schematic diagram of the assembly structure of the inlet lip and the front upper wall panel.

[0047] Figure 13 It is a schematic diagram of the front skin structure.

[0048] Figure 14 It is a schematic diagram of the structure at the U-shaped belt-like space in the front skin.

[0049] Figure 15 It is a schematic diagram of the middle skin structure.

[0050] Figure 16 It is a schematic diagram of the middle upper wall panel structure.

[0051] Figure 17 It is a schematic diagram of the middle upper wall panel structure.

[0052] Figure 18 It is a schematic diagram of the middle upper wall panel structure.

[0053] Figure 19 It is a schematic diagram of the middle skin structure.

[0054] Figure 20 It is a schematic diagram of the middle left wall panel structure.

[0055] Figure 21 It is a schematic diagram of the middle skin structure.

[0056] Figure 22 It is a schematic diagram of the left cabin door panel structure.

[0057] Figure 23 It is a schematic diagram of the middle skin structure.

[0058] Figure 24 It is a schematic diagram of the second longitudinal beam structure.

[0059] Figure 25 It is a schematic diagram of the first short beam structure.

[0060] Figure 26 It is a schematic diagram of the second short beam structure.

[0061] Figure 27 It is a schematic diagram of the installation joint structure.

[0062] Figure 28 It is a schematic structural diagram of the installation section.

[0063] Figure 29 It is a schematic structural diagram of the installation section.

[0064] Figure 30 It is a schematic structural diagram of the installation section.

[0065] In the figure: 1. Front upper wall panel, 2. Inlet lip, 3. Front lower wall panel, 4. Lip skin, 5. Web member, 6. First U-shaped frame, 7. Plate-shaped flange, 8. Front lower wall panel skin, 9. Second U-shaped frame, 10. Elastic sealing strip, 11. Front upper wall panel skin, 12. Upper wall panel stiffener, 13. First connecting pad, 14. Second connecting pad, 15. Lower wall panel stiffener, 16. Middle upper wall panel, 17. Middle left wall panel, 18. Middle right wall panel, 19. Installation beam, 20. U-shaped reinforcement beam, 21. Middle upper wall panel skin, 22. Middle left wall panel skin, 23. First connecting plate, 24. Middle right wall panel skin, 25. Second connecting plate, 26. First longitudinal beam, 27. Second longitudinal beam, 28. Third longitudinal beam, 29. First short beam, 30. Second short beam, 31. Second longitudinal beam web, 32. First short beam web, 33. Second short beam web, 34. First cross beam, 35. Second cross beam, 36. Left cabin door panel, 37. Right cabin door panel, 38. Cabin door skin, 39. Cabin door rib, 40. Cabin door hinge installation beam, 41. Front firewall, 42. Rear firewall, 43. Upper firewall, 44. First through hole, 45. Second through hole, 46. Upper fireproof board, 47. Lower fireproof board, 48. Side stiffener, 49. First arc-shaped stiffener, 50. Second arc-shaped stiffener, 51. Protrusion, 52. Reinforcement link, 53. Eighth joint, 54. Ninth joint, 55. Third reinforcement beam, 56. Upper fireproof board, 57. Corner beam, 58. U-shaped beam, 59. Engine rear suspension point installation box, 60. First adapter plate, 61. Installation frame, 62. Tie rod system, 63. First joint, 64. Second joint, 65. Third joint, 66. Fourth joint, 67. Fifth joint, 68. Sixth joint, 69. Seventh joint, 70. Left suspension point lower tie rod, 71. Left suspension point upper tie rod, 72. Upper suspension point left tie rod, 73. Upper suspension point right tie rod, 74. Right suspension point upper tie rod, 75. Right suspension point lower tie rod, 76. First firewall reinforcement beam, 77. Second firewall reinforcement beam, 78. Third firewall reinforcement beam, 79. Third U-shaped frame, 80. Shock pad, 81. Second adapter plate, 82. Tail cross beam, 83. Left wall panel hinge installation beam, 84. Rear section skin. Detailed implementation method

[0066] In view of the problems existing in the prior art, the utility model aims to strengthen the structural strength of the nacelle through an innovative nacelle design, while maintaining or reducing the overall weight of the nacelle, reducing the maintenance cost, and optimizing the load transfer efficiency, so as to improve the overall performance and safety of the aircraft.

[0067] As Figures 1 to 30 shown, an engine nacelle includes a front firewall 41, an upper firewall 43, a rear firewall 42, a front section skin, a middle section skin, a rear section skin 84, and a mounting frame 61.

[0068] As Figure 2 shown, the front firewall 41 and the rear firewall 42 are arranged relatively parallel. A first through hole 44 is provided on the front firewall 41, and a second through hole 45 is provided on the rear firewall 42. The first through hole 44 and the second through hole 45 are used for assembling with an aircraft engine. The rear part of the engine is placed in the first through hole 44, and an exhaust pipe 40 is arranged at the rear part of the engine. The middle part of the exhaust pipe of the engine is located in the second through hole; the upper firewall 43 is arranged between the front firewall 41 and the rear firewall 42. The front end of the upper firewall 43 is connected to the front firewall 41, and the rear end is connected to the rear firewall 42, and the upper firewall 43 is located above the first through hole 44 and the second through hole 45.

[0069] Through the above settings, the fire area is divided into three parts. The first fire area is located on the front side of the front firewall 41, the second fire area is located in the area surrounded by the front firewall 41, the upper firewall 43, and the rear firewall 42, and the third fire area is located on the rear side of the rear firewall 42, realizing the separation of the three fire areas. When a hidden danger occurs in the engine and a fire breaks out, the spread of the fire can be effectively prevented.

[0070] The mounting frame 61 is a U-shaped structure with an open bottom and is located on the front side of the front firewall 41; the mounting frame 61 is connected to the suspension points on the engine. There are three groups of suspension points at the front part of the engine, namely a left suspension point, an upper suspension point, and a right suspension point. The left suspension point is located on the left part of the engine, the upper suspension point is located on the upper part of the engine, and the right suspension point is located on the right part of the engine. The mounting frame 61 is a U-shaped arc frame structure, which is arranged above the engine and is connected to the three suspension points of the engine through connecting pieces. Specifically, the left free end of the mounting frame 61 is connected to the left suspension point of the engine, the right free end of the mounting frame 61 is connected to the right suspension point of the engine, and the middle part of the mounting frame 61 is connected to the upper suspension point of the engine. The middle part of the mounting frame 61 is specifically the top end position of the U-shaped arc frame.

[0071] As Figure 7As shown, the front-section skin includes a front-section upper wall panel 1, an inlet lip 2, a front-section lower wall panel 3, and a U-shaped reinforcement beam 20. The front-section upper wall panel 1 is located above the inlet lip 2 and the front-section lower wall panel 3. The inlet lip 2 is located at the front side of the front-section lower wall panel 3. The front-section upper wall panel 1, the inlet lip 2, and the front-section lower wall panel 3 are connected to form the front skin of the engine nacelle with a conical structure.

[0072] The front end of the inlet lip 2 is connected to the engine by bolts. The lower part of the inlet lip 2 is provided with an air inlet for effectively guiding air into the engine to ensure that the air flows in at an appropriate speed and angle to meet the operating requirements of the engine. A flange is provided at the rear end of the air inlet of the inlet lip 2, and the inlet lip 2 is connected to the engine by bolts through the flange.

[0073] As Figure 15 shown, the front-section upper wall panel 1 is generally a semi-conical plate-like structure. The upper ends of the inlet lip 2 and the front-section lower wall panel 3 are both connected to the lower end of the front-section upper wall panel 1 by rivets. The front end of the front-section lower wall panel 3 is connected to the rear end of the inlet lip 2, and the connection structure is specifically a non-rigid connection. The rear end of the front-section upper wall panel 1 is connected to the mounting frame 61, and the rear end of the front-section lower wall panel 3 is connected to the U-shaped reinforcement beam 20;

[0074] The middle-section skin includes a middle-section upper wall panel 16, a middle-section left wall panel 17, a middle-section right wall panel 18, a left cabin door panel 36, and a right cabin door panel 37. The right end of the middle-section left wall panel 17 is connected to the left end of the middle-section upper wall panel 16. The left end of the middle-section right wall panel 18 is connected to the right end of the middle-section upper wall panel 16. The upper end of the left cabin door panel 36 is connected to the lower end of the middle-section left wall panel 17 by a hinge. The upper end of the right cabin door panel 37 is connected to the lower end of the middle-section right wall panel 18 by a hinge. The front ends of the middle-section left wall panel 17, the middle-section right wall panel 18, and the middle-section upper wall panel 16 are all connected to the mounting frame 61. The rear end of the middle-section upper wall panel 16 is connected to the front firewall 41, and the rear ends of the middle-section left wall panel 17 and the middle-section right wall panel 18 are connected to the rear firewall 42.

[0075] The inner surface of the middle-section left wall panel 17 abuts against the left ends of the front firewall 41 and the upper firewall 43. The inner surface of the middle-section right wall panel 18 abuts against the right ends of the front firewall 41 and the upper firewall 43.

[0076] The rear-section skin 84 is arranged at the rear side of the middle-section skin, and the front end of the rear-section skin 84 is connected to the rear firewall 42.

[0077] The lower edge of the rear firewall 42 is an arc structure. The front end of the rear section skin 84 is riveted to the lower edge of the rear firewall 42. A through hole for the exhaust pipe to pass through is provided on the rear section skin 84. The front end of the exhaust pipe is used to connect to the engine exhaust port. The rear end of the exhaust pipe passes through the through hole on the rear section skin 84, and the outer peripheral position of the through hole on the rear section skin 84 is connected to the exhaust pipe for fixing the exhaust pipe.

[0078] Through the above settings, it realizes the replacement of the rivet connection structure between the traditional middle section skin, the upper firewall and the front firewall, which can ensure the connection stability between the front section skin, the middle section skin, the rear section skin and the engine, the front firewall, the upper firewall and the rear firewall, reduce the number of rivets and other connecting parts while ensuring the overall structural strength, and reduce the overall weight of the engine nacelle.

[0079] As Figure 4 shown, as a preferred technical solution of the present invention, the front firewall 41 includes an upper firewall plate 46 and a lower firewall plate 47. The lower end of the upper firewall plate 46 is connected to the upper end of the lower firewall plate 47. Semi-circular notches are provided in the lower part of the upper firewall plate 46 and the upper part of the lower firewall plate. The semi-circular notches on the upper firewall plate 46 and the lower firewall plate 47 enclose a first through hole 44.

[0080] Specifically, a convex portion 51 is provided at the lower end of the upper firewall plate 46. The convex portion 51 is a plate-like structure extending downward at the lower end position of the upper firewall plate 46. The convex portion 51 of the upper firewall plate 46 is located at the rear side of the lower firewall plate 47, and the convex portion 51 of the upper firewall plate 46 is connected to the lower firewall plate 47. The connection method can be selected as riveting or screwing. When installing the engine, first connect the upper firewall plate 46 to the engine, and then connect the lower firewall plate 47 to the engine and the upper firewall plate 46. The upper firewall plate 46 and the lower firewall plate 47 are designed to be detachable. When disassembling the engine, the lower firewall plate 47 can be disassembled together with the engine without disassembling the upper firewall plate 46.

[0081] To ensure the structural strength of the upper firewall plate 46, the front firewall plate further includes side reinforcing ribs 48, a first arc reinforcing rib 49, and a second arc reinforcing rib 5010.

[0082] The side reinforcing ribs 48 are arranged on the plate surface of the upper firewall plate 46. There are two groups of side reinforcing ribs 48. The first side reinforcing rib is arranged on the left part of the upper firewall plate 46, and the second side reinforcing rib is arranged on the right part of the upper firewall plate 46. The side reinforcing ribs 48 are provided with flanges, and the flanges are used to be riveted to the middle left wall plate 17 and the middle right wall plate 18 of the middle section skin. While enhancing the structural strength of the left and right ends of the upper firewall plate 46 through the arrangement of the side reinforcing ribs 48, as a transfer part, it is connected to the middle section skin to improve the connection strength with the middle section skin.

[0083] The first arc-shaped reinforcing rib 49 is an arc-shaped structure, which is fitted at the circumferential position of the lower semi-circular notch of the upper fireproof board 46 for strengthening the semi-circular notch position of the upper fireproof board 46. The first arc-shaped reinforcing rib 49 and the upper fireproof board 46 can be connected by riveting. The second arc-shaped reinforcing rib 5010 is an arc-shaped structure, which is fitted at the circumferential position of the upper semi-circular notch of the lower fireproof board 47 for strengthening the semi-circular notch position of the lower fireproof board 47. The first arc-shaped reinforcing rib 49 and the upper fireproof board 46 can be connected by riveting, and the second arc-shaped reinforcing rib 5010 and the lower fireproof board 47 can be connected by riveting.

[0084] The front firewall 41 further includes connecting pieces, which are respectively arranged on the first arc-shaped beam and the second arc-shaped beam and are used for connecting with the flange on the engine. To improve the connection strength between the front firewall 41 and the engine, several groups of the connecting pieces are provided and are evenly arranged in an array along the circumference of the first through hole 44 on the outer periphery of the first through hole 44.

[0085] As Figure 2 、 Figure 3 shown, as a preferred technical solution of the present utility model, it further includes a reinforcing connecting rod 52. The front end of the reinforcing connecting rod 52 is connected to the front firewall 41, and the rear end of the reinforcing connecting rod 52 is connected to the rear firewall 42. There are two groups of the reinforcing connecting rods 52 in total. The position where the first reinforcing connecting rod is connected to the front firewall 41 is on the left side of the first through hole 44, and the position where the first reinforcing connecting rod is connected to the rear firewall 42 is on the left side of the second through hole 45;

[0086] The position where the second reinforcing connecting rod is connected to the front firewall 41 is on the right side of the first through hole 44, and the position where the second reinforcing connecting rod is connected to the rear firewall 42 is on the right side of the second through hole 45. The stability of the overall structure is improved by the arrangement of the reinforcing connecting rod 52.

[0087] As a supplement to the above technical solution, the front end of the reinforcing connecting rod 52 is connected to the front firewall 41 through an eighth joint 53. Specifically, the eighth joint 53 is a plate-shaped structure, and the eighth joint 53 is screwed to the upper fireproof board 46 and the side reinforcing rib 48. Through the arrangement of the eighth joint 53, the connection strength of the upper fireproof board and the side reinforcing rib 48 is improved. One end of the eighth joint 53 at the center of the first through hole 44 is connected to the flange on the engine.

[0088] The above-mentioned eighth joint 53 is connected to the front fireproof board, the side reinforcing rib 48, the engine, and the first reinforcing connecting rod at the same time, and can play a role in transmitting multi-party loads to ensure the structural stability.

[0089] To avoid the situation where the directions of the bearing forces of the two strengthening linkages 52 are different, causing shear force to the rear firewall 42. For example, the first strengthening linkage applies a tensile force towards the front side to the rear firewall 42, and the second strengthening linkage applies a tensile force towards the rear side to the rear firewall 42, affecting the stability of the rear firewall 42. As a preferred technical solution of the present utility model, the rear ends of the two strengthening linkages 52 are both connected to the rear firewall 42 through the ninth joints 54, and a third strengthening beam 55 is provided between the ninth joints 54 at the rear ends of the two strengthening linkages 52. Through the setting of the third strengthening beam 55, the forces applied to the rear firewall 42 by the two groups of strengthening linkages 52 can be conducted through the third strengthening beam 55.

[0090] As a preferred technical solution of the present utility model, the front end of the strengthening linkage 52 is hinged to the eighth joint 53, and the front end of the strengthening linkage 52 is hinged to the ninth joint 54. Hinging can enable the strengthening linkage 52 to remain stable when subjected to external forces, and the hinge points can absorb and disperse part of the impact force, reducing the impact on the overall structure.

[0091] As Figure 5 shown, as a preferred technical solution of the present utility model, the upper firewall 43 includes an upper fireproof board 56, an angle beam 57, and a U-shaped beam 58.

[0092] Both the left and right ends of the upper fireproof board 56 are provided with flanges for abutting against the middle section skin. The left end of the upper fireproof board 56 is connected to the left wall plate 17 of the middle section of the upper firewall 43, and the right end of the upper fireproof board 56 is connected to the right wall plate 18 of the middle section of the upper firewall 43. Through the flange design at both the left and right ends of the upper fireproof board 56, the connection stability with the middle section skin is enhanced.

[0093] The angle beam 57 is used to connect the upper fireproof board 56 to the front firewall 41. The angle beam 57 is an L-shaped long beam with a cross-section composed of two mutually perpendicular plate surfaces. The horizontal plate surface of the angle beam 57 is riveted to the upper fireproof board 56, and the vertical plate surface of the angle beam 57 is connected to the front firewall 41. The front end of the upper fireproof board 56 is connected to the front firewall 41 through the angle beam 57.

[0094] The U-shaped beam 58 has a U-shaped cross-section structure, which includes a top plate surface, a bottom plate surface, and a web. The top plate surface and the bottom plate surface are connected by a vertically arranged web. The bottom plate surface of the U-shaped beam 58 is connected to the upper firewall 43, the web is connected to the rear firewall 42, and its top plate surface is used to connect to the wing of the aircraft, enhancing the connection strength between the firewall and the wing.

[0095] As a preferred technical solution of the present utility model, the upper firewall 43 further includes an engine rear suspension point mounting box 59. A through hole is vertically formed on the upper firewall plate 56. A groove is provided on the lower bottom surface of the engine rear suspension point mounting box 59. The engine rear suspension point mounting box 59 is located above the through hole on the upper firewall plate 56, and the lower end of the engine rear suspension point mounting box 59 is connected to the upper firewall plate 56. The connection position between the engine rear suspension point mounting box 59 and the upper firewall plate 56 is located on the outer periphery of the through hole on the upper firewall plate 56, so that the through hole on the upper firewall plate 56 is communicated with the inner space of the groove of the engine rear suspension point mounting box 59. The rear suspension point of the engine is connected to the engine rear suspension point mounting box 59 through an adapter. One end of the adapter is connected to the rear suspension point of the engine, and the other end passes through the through hole on the upper firewall plate 56 and is connected to the engine rear suspension point mounting box 59. The upper end of the engine rear suspension point mounting box 59 is used to be connected to the wing.

[0096] In the above structure, through the setting of the engine rear suspension point mounting box 59, the isolation between the second fire zone and the wing is realized. At the same time, through the design of the engine rear suspension point mounting box 59, the connection between the engine and the wing is realized, reducing the load borne by the upper firewall plate 56 and improving the structural stability of the upper firewall plate 56.

[0097] As a preferred technical solution of the present utility model, the upper firewall further includes a first adapter plate 60. The first adapter plate 60 is vertically arranged on the upper firewall plate 56. The lower end of the first adapter plate 60 is connected to the upper firewall plate 56, and the front end is connected to the front firewall 41. The upper end of the first adapter plate 60 is used to be connected to the wing and is used to support the wing.

[0098] The upper firewall 43 further includes load-bearing support plates. There are two groups of load-bearing support plates. The first load-bearing support plate is vertically arranged on the left side of the engine rear suspension point mounting box 59, and the first load-bearing support plate is vertically arranged on the right side of the engine rear suspension point mounting box 59

[0099] As Figure 21 、 Figure 22 shown, as a preferred technical solution of the present utility model, the upper end of the left cabin door panel 36 is connected to the middle section left wall panel 17 through a left cabin door hinge, and the upper end of the right cabin door panel 37 is connected to the middle section right wall panel 18 through a right cabin door hinge.

[0100] The left cabin door panel 36 and the right cabin door panel 37 have the same structure. The left cabin door panel 36 includes a cabin door skin 38, cabin door ribs 39, and a cabin door hinge mounting beam 40. The cabin door ribs 39 are arranged inside the cabin door skin 38 and are connected to the cabin door skin 38 through rivets to support the cabin door skin 38.

[0101] The cabin door hinge mounting beam 40 is arranged at the upper part of the left cabin door skin 38,

[0102] The hatch hinge mounting beam 40 is riveted to the inner surface of the left hatch skin 38 and is located at the upper end of the left hatch skin 38, providing structural strength for the hatch hinge mounting beam 40.

[0103] The middle section left wall panel 17 further includes a left wall panel hinge mounting beam 83. The left wall panel hinge mounting beam 83 is riveted to the inner surface of the middle section left wall panel 17 and is located at the lower end of the middle section left wall panel 17. The left wall panel hinge mounting beam 83 is provided for connecting with the left hatch door panel 36, and at the same time increasing the structural strength of the middle section left wall panel skin 22.

[0104] The left hatch hinge includes a first leaf, a second leaf, and a hinge shaft. The first leaf and the second leaf are connected by the hinge shaft. The first leaf is connected to the left wall panel hinge mounting beam 83, and the second leaf is connected to the hatch hinge mounting beam 40. Through the above structure, the flipping function of the left hatch door panel 36 relative to the middle section left wall panel 17 is realized.

[0105] Correspondingly, the middle section right wall panel 18 further includes a right wall panel hinge mounting beam. The right hatch door wall panel is connected to the middle section right wall panel 18 through a right hatch hinge, and the connection method is the same as the connection method between the left hatch door wall panel and the middle section right wall panel 18.

[0106] As a supplement to the above technical solution, the hatch rib 39 is provided with a weight reduction hole for reducing the weight of the hatch rib 39.

[0107] As Figure 4 shown, as a preferred technical solution of the present utility model, flanges are provided at the side edges of the side strengthening ribs 48 on the front firewall 41, the left and right ends of the upper fireproof board 56, and the side edges of the rear firewall 42 for connecting with the outer middle section skin.

[0108] As Figures 7 to 14 shown, as a preferred technical solution of the present utility model, the air inlet lip 2 includes a lip skin 4, a web member 5, and a first U-shaped frame 6. The web member 5 is riveted to the inner side of the lip skin 4 and is located at the rear of the lip skin 4. The web member 5 is in a U-shaped ribbed plate structure. A plate-shaped flange 7 is provided on the side of the web member 5 close to the lip skin 4, and the web member 5 is riveted to the lip skin 4 through the plate-shaped flange 7. The first U-shaped frame 6 is in a U-shaped structure, and the first U-shaped frame 6 is arranged on the web member 5 and there is a certain distance between the first U-shaped frame 6 and the plate-shaped flange 7 on the web member 5;

[0109] The front section lower wall panel 3 includes a front section lower wall panel skin 8 and a second U-shaped frame 9. The second U-shaped frame 9 is riveted to the front end of the front section lower wall panel skin 8. The front end face of the second U-shaped frame 9 is a flat plate surface, and the width of the front end face of the second U-shaped frame 9 is greater than the distance between the first U-shaped frame 6 and the plate-shaped flange 7 on the web member 5.

[0110] The second U-shaped frame 9 abuts against the plate-shaped flange 7 of the web member 5 and the rear end of the first U-shaped frame 6.

[0111] By dividing the front skin of the engine nacelle into the inlet lip 2, the front upper wall panel 1, and the front lower wall panel 3, it is possible to ensure the structural strength of the front skin of the engine nacelle without using rivets to connect the front upper wall panel 1 and the front lower wall panel 3.

[0112] As Figure 14 shown, as a supplement to the above technical solution, in order to improve the connection sealing performance between the front lower wall panel 3 and the inlet lip 2, an elastic sealing strip 10 is provided between the plate-shaped flange 7 on the first U-shaped frame 6 and the web member 5. As Figure 8 shown, the second U-shaped frame 9, and the web member 5, the plate-shaped flange 7, and the first U-shaped frame 6 on the inlet lip 2 enclose a U-shaped strip space with a rectangular cross-section. The elastic sealing strip 10 is arranged in the U-shaped strip space. After the front lower wall panel 3, the front upper wall panel 1, and the inlet lip 2 are assembled, the second U-shaped frame 9 provided at the front end of the front lower wall panel 3 can squeeze the elastic sealing strip 10, causing the elastic seal to undergo compressive deformation and filling the U-shaped strip space, achieving the sealing effect between the front end of the front lower wall panel 3 and the rear end of the inlet lip 2.

[0113] To ensure that the plate-shaped flange 7 on the web member 5 and the rear end of the first U-shaped frame 6 can better abut against the front end of the front lower wall panel 3, the plate-shaped flange 7 and the first U-shaped frame 6 have the same width.

[0114] Through the above settings, it is realized that there is no need to rivet the front lower wall panel 3 and the inlet lip 2 during the assembly process. After the inlet lip 2 and the front lower wall panel 3 are connected to the front upper wall panel 1, the front end of the front lower wall panel 3 can abut against the rear end of the inlet lip 2. At the same time, through the settings of the first U-shaped frame 6, the web member 5, and the elastic sealing strip 10, the sealing connection effect between the two is achieved, which can improve the assembly efficiency while ensuring the sealing effect.

[0115] As a supplement to the above technical solution, the plate-shaped flange 7 on the web member 5 and the lip skin 4 can be connected by rivets, and the rear ends of the plate-shaped flange 7 on the web member 5 and the lip skin 4 are located in the same vertical plane.

[0116] As Figure 12As shown, as a preferred technical solution of the present utility model, the front upper wall plate 1 includes a front upper wall plate skin 11 and an upper wall plate reinforcing rib 12. The upper wall plate reinforcing rib 12 is arranged inside the upper wall plate and riveted to the front upper wall plate skin 11 for supporting the front upper wall plate skin 11. The air inlet lip further includes a first connecting backing plate 13. The lower part of the first connecting backing plate 13 is located inside the lip skin 4 and connected to the lip skin 4, preferably by riveting. The upper part of the first connecting backing plate 13 protrudes above the upper end of the lip skin 4 and is located inside the front upper wall plate skin 11. The upper part of the first connecting backing plate 13 is connected to the front upper wall plate skin 11 by a quick-release lock.

[0117] As a supplement to the above technical solution, the upper end of the first connecting backing plate 13 is provided with a flanging. The flanging of the first connecting backing plate 13 is riveted to the upper wall plate reinforcing rib 12 of the front upper wall plate 1 above the flanging, and the stable connection between the front upper wall plate 1 and the air inlet lip 2 is realized through the above setting.

[0118] As Figure 9 As shown, as a preferred technical solution of the present utility model, the front lower wall plate 3 further includes a second connecting backing plate 14. The lower part of the second connecting backing plate 14 is located inside the front lower wall plate skin 8 and connected to the front lower wall plate skin 8. The upper part of the second connecting backing plate 14 protrudes above the upper end of the front lower wall plate skin 8 and is located inside the front upper wall plate skin 11. The second connecting backing plate 14 is connected to the front upper wall plate skin 11 by a quick-release lock.

[0119] As a supplement to the above technical solution, the upper end of the second connecting backing plate 14 is provided with a flanging. The flanging of the second connecting backing plate 14 is riveted to the upper wall plate reinforcing rib 12 above the flanging, and the stable connection between the front lower wall plate 3 and the front upper wall plate 1 is realized through the above setting.

[0120] As Figure 10 As shown, as a supplement to the technical solution of the present utility model, the front lower wall plate 3 further includes a lower wall plate reinforcing rib 15. The lower wall plate reinforcing rib 15 is arranged inside the front lower wall plate skin 8 and riveted to the front lower wall plate skin 8. There is a groove on the rear end face of the second U-shaped frame 9. The front part of the lower wall plate reinforcing rib 15 is bent upward and placed in the groove on the rear end face of the second U-shaped frame 9. A rivet passes through the front part of the lower wall plate reinforcing rib 15, the second U-shaped frame 9, and the front lower wall plate skin 8 to rivet the lower wall plate reinforcing rib 15, the second U-shaped frame 9, and the front lower wall plate skin 8.

[0121] As a supplement to the technical solution of the present utility model, the inlet lip 2 further includes a conical plate connecting member. The conical plate connecting member is arranged at the front end of the lip skin 4. The inlet lip 2 is bolted to the engine through the conical plate connecting member. The front end of the front upper wall plate is screwed to the conical plate connecting member to achieve the purpose of connecting the front upper wall plate to the front end of the inlet lip 2.

[0122] As Figures 15 to 26 As shown, as a supplement to the technical solution of the present utility model, the middle section skin further includes a tail cross beam 82. The middle section upper wall plate 16 includes a middle section upper wall plate skin 21.

[0123] The middle section left wall plate 17 includes a middle section left wall plate skin 22 and a first connecting plate 23. The first connecting plate 23 is arranged on the lower surface of the middle section left wall plate skin 22 by rivets. The right part of the first connecting plate 23 protrudes from the right end of the middle section left wall plate skin 22 and extends below the middle section upper wall plate skin 21. The middle section upper wall plate skin 21 is connected to the first connecting plate 23 by a quick release lock.

[0124] The middle section right wall plate 18 includes a middle section right wall plate skin 24 and a second connecting plate 25. The second connecting plate 25 is arranged on the lower surface of the middle section right wall plate skin 24 by rivets. The left part of the second connecting plate 25 protrudes from the left end of the middle section right wall plate skin 24 and extends below the middle section upper wall plate skin 21. The middle section upper wall plate skin 21 is connected to the second connecting plate 25 by a quick release lock.

[0125] The mounting beam 19 is arranged on the mounting frame 61. Specifically, the mounting beam 19 is a U-shaped beam 58 structure with the same radian as the mounting frame 61. The mounting beam 19 is located below the middle section upper wall plate skin 21, the middle section left wall plate skin 22 and the middle section right wall plate skin 24. The front end of the middle section upper wall plate skin 21 is detachably connected to the mounting beam 19 by a quick release lock. The front ends of the middle section left wall plate skin 22 and the middle section right wall plate skin 24 are both connected to the mounting beam 19 by quick release locks.

[0126] The tail cross beam 82 is riveted to the front firewall 41. The rear end of the middle section upper wall plate skin 21 of the middle section upper wall plate 16 is linked to the tail cross beam 82 by a quick release lock.

[0127] Both the left end and the right end of the tail cross beam 82 are connected to the leading edge rib plate in the wing, the middle section left wall plate 17 and the middle section right wall plate 18.

[0128] Notches are provided at the upper parts of the middle section left wall plate 17 and the middle section right wall plate 18. The shape of the notches is the same as the leading edge of the wing. The leading edge of the wing is inserted into the notches of the middle section left wall plate 17 and the middle section right wall plate 18, and the leading edge of the wing is connected to the skin at the notch positions of the middle section left wall plate 17 and the middle section right wall plate 18.

[0129] Through the above settings, a convenient detachable connection is achieved between the middle-section upper skin 21 of the middle-section upper wall panel 16 and the middle-section left wall panel 17, the middle-section right wall panel 18, and the mounting beam 19. The disassembly and assembly are simple and fast through the setting of the quick-release lock. When the engine is overhauled, only the quick-release lock for mounting the middle-section upper skin 21 needs to be disassembled to remove the middle-section upper wall panel 16.

[0130] In the prior art, the middle-section skin of the engine nacelle is a whole skin. Corresponding to the present utility model, the middle-section skin is the whole plate of the middle-section left wall panel 17, the middle-section right wall panel 18, and the middle-section upper wall panel 16. When the engine is working, shear forces are generated by the gas-dynamic process inside the engine and the interaction with the overall aerodynamic layout of the aircraft. The middle-section skin of the engine nacelle acts as a shear panel. However, in the present utility model, since the middle-section upper wall panel 16 is detachably connected to the middle-section left wall panel 17 and the middle-section right wall panel 18, the original middle-section skin shear panel structure is damaged.

[0131] In view of this, as Figures 16 to 18 shown, Figures 24 to 26 shown, the middle-section upper wall panel 16 further includes upper wall panel longitudinal beams and upper wall panel cross beams. There are three groups of the upper wall panel longitudinal beams, namely the first longitudinal beam 26, the second longitudinal beam 27, and the third longitudinal beam 28. The three groups of upper wall panel longitudinal beams are arranged in sequence from left to right on the lower bottom surface of the middle-section upper skin 21, and are all connected to the middle-section upper skin 21 by rivets.

[0132] The upper wall panel cross beam includes a first short beam 29 and a second short beam 30. The left end of the first short beam 29 is connected to the first longitudinal beam 26, and the right end of the first short beam 29 is connected to the second longitudinal beam 27;

[0133] The left end of the second short beam 30 is connected to the second longitudinal beam 27, and the right end of the second short beam 30 is connected to the third longitudinal beam 28.

[0134] Through the setting of the three groups of upper wall panel longitudinal beams and the upper wall panel cross beams, the effect that the middle-section upper wall panel 16 acts as a shear panel is achieved. At the same time, through the above setting of the upper wall panel cross beam, the structural stiffness of the windward surface of the partial skin of the middle-section upper wall panel 16 is improved, and the technical problem of deformation of the middle-section upper skin 21 during the flight of the aircraft is avoided.

[0135] As a supplement to the above technical solution, the second longitudinal beam 27 includes a second longitudinal beam web 31. The upper end and the lower end of the second longitudinal beam web 31 are both provided with flanges, so that the second longitudinal beam 27 is a U-shaped beam 58 structure with a notch as a whole, and the notch of the second longitudinal beam 27 faces the direction of the first short beam 29.

[0136] The first short beam 29 includes a first short beam web 32, and flanges are provided at both the upper end and the lower end of the first short beam web 32, making the first short beam 29 an overall Z-shaped beam structure. The flange provided at the upper end of the first short beam web 32 is used for riveting with the skin to support the skin, and the flange at the lower end of the first short beam web 32 is used to jointly increase the structural strength of the first short beam web 32 with the flange at the upper end of the first short beam web 32. The right end of the first short beam 29 is bent downward and inserted into the notch of the second longitudinal beam 27. The upper flange of the first short beam web 32 is located below the upper flange of the second longitudinal beam web 31, and the upper flange of the first short beam web 32, the upper flange of the second longitudinal beam web 31, and the middle section upper wall panel skin 21 are riveted together by rivets.

[0137] The lower flange of the first short beam web 32 is located above the lower flange of the second longitudinal beam web 31, and the lower flange of the first short beam web 32 and the lower flange of the second longitudinal beam web 31 are riveted together by rivets.

[0138] As a supplement to the above technical solution, the second short beam 30 has the same structure as the first short beam 29, including a second short beam web 33, and flanges are provided at both the upper end and the lower end of the second short beam web 33, making the second short beam 30 an overall Z-shaped beam structure. The upper flange of the second short beam web 33 is used for riveting with the skin to support the skin. The left end of the second short beam 30 abuts against the second longitudinal beam 27, and the lower flange of the second short beam web 33 is connected to the lower flange of the second longitudinal beam web 31 through a connecting plate. The connecting plate is a flat plate structure. One end of the connecting plate is riveted to the lower flange of the second short beam web 33, and the other end of the connecting plate is riveted to the lower flange of the second longitudinal beam web 31.

[0139] In the above technical solution, the connection methods of the first short beam 29, the second short beam 30 and the second longitudinal beam 27 are different. The main reason is that the second longitudinal beam 27 is a U-shaped beam 58 structure, so there is only a notch on one side. If it is necessary to have notches on both sides of the second longitudinal beam 27, the second longitudinal beam 27 needs to be set as an I-beam structure. However, the I-beam structure design will increase the material consumption of the second longitudinal beam 27 and at the same time increase the weight of the second longitudinal beam 27. In view of this, by connecting the second longitudinal beam 27 and the second cross beam 35 through a connecting plate, both the connection strength and the weight reduction effect of the second longitudinal beam 27 can be achieved.

[0140] As a supplement to the above technical solution, the left end of the first short beam 29 is connected to the first longitudinal beam 26 through an angle piece, and the right end of the second short beam 30 is connected to the third longitudinal beam 28 through an angle piece. The above-mentioned angle piece can be an L-shaped angle piece. Taking the connection between the first short beam 29 and the first longitudinal beam 26 as an example, the first part of the angle piece is riveted to the web 32 of the first short beam through a rivet, and the second part of the angle piece is riveted to the first longitudinal beam 26 through a rivet. The connection method between the second short beam 30 and the third longitudinal beam 28 is the same as that between the first short beam 29 and the first longitudinal beam 26.

[0141] As a preferred technical solution of the present utility model, the upper wall panel cross beam further includes a first cross beam 34 and a second cross beam 35. The first cross beam 34 and the second cross beam 35 are riveted to the lower bottom surface of the middle section upper wall panel skin 21. The first cross beam 34 is located at the front end of the first longitudinal beam 26, the second longitudinal beam 27, and the third longitudinal beam 28 to support the front part of the middle section upper wall panel skin 21. The second cross beam 35 is located at the rear end of the first longitudinal beam 26, the second longitudinal beam 27, and the third longitudinal beam 28 to support the rear part of the middle section upper wall panel skin 21.

[0142] The lower end of the first cross beam 34 is provided with a bent edge. The bent edge at the lower end of the first cross beam 34 is located below the second longitudinal beam 27, and the bent edge at the lower end of the web of the second longitudinal beam 27 is riveted to the bent edge at the lower end of the first cross beam 34.

[0143] The lower end of the second cross beam 35 is provided with a bent edge. The bent edge at the lower end of the second cross beam 35 is located below the second longitudinal beam 27, and the bent edge at the lower end of the web of the second longitudinal beam 27 is riveted to the bent edge at the lower end of the second cross beam 35.

[0144] As a supplement to the above technical solution, weight reduction holes are provided on both the upper wall panel longitudinal beam and the upper wall panel cross beam to reduce the weight of the upper wall panel longitudinal beam and the upper wall panel cross beam.

[0145] As Figures 27 to 30 shown, as a preferred technical solution of the present utility model, it further includes a tie rod system 62. The tie rod system 62 includes a first joint 63, a second joint 64, a third joint 65, a fourth joint 66, a fifth joint 67, a sixth joint 68, a seventh joint 69, a left suspension point lower tie rod 70, a left suspension point upper tie rod 71, an upper suspension point left tie rod 72, an upper suspension point right tie rod 73, a right suspension point lower tie rod 75, and a right suspension point upper tie rod 74;

[0146] Among them, the first joint 63, the second joint 64, and the third joint 65 are arranged on the mounting frame 61, and the first joint 63 is located at the left end of the mounting frame 61, the second joint 64 is located at the upper end of the mounting frame 61, and the third joint 65 is located at the right end of the mounting frame 61.

[0147] The fourth joint 66, the fifth joint 67, the sixth joint 68, and the seventh joint 69 are arranged on the front firewall 41. The fourth joint 66 is located behind the first joint 63. The fifth joint 67 is located above the fourth joint 66. The seventh joint 69 is located behind the third joint 65. The sixth joint 68 is located above the seventh joint 69.

[0148] A left suspension point lower pull rod 70 is connected between the first joint 63 and the fourth joint 66, and a left suspension point upper pull rod 71 is connected between the first joint 63 and the fifth joint 67;

[0149] An upper suspension point left pull rod 72 is connected between the second joint 64 and the fifth joint 67, and an upper suspension point right pull rod 73 is connected between the second joint 64 and the sixth joint 68;

[0150] A right suspension point upper pull rod 74 is connected between the third joint 65 and the sixth joint 68, and a right suspension point lower pull rod 75 is connected between the third joint 65 and the seventh joint 69.

[0151] Through the above structural design, compared with the traditional cantilever beam structure, the load of the mounting joint system can be transmitted along the axial direction of the pull rod, enabling it to better balance and offset the steering force and torsional load. In addition, a triangular stable structure is formed between two adjacent pull rods. For example, the left suspension point lower pull rod 70, the left suspension point upper pull rod 71, and the front firewall 41 form a triangular structure, the left suspension point upper pull rod 71, the upper suspension point left pull rod 72, and the mounting frame 61 form a triangular structure, and the upper suspension point left pull rod 72, the upper suspension point right pull rod 73, and the front firewall 41 form a triangular structure, making the structure more stable. The traditional cantilever beam structure generally only sets two or three groups of cantilever beams to connect the mounting frame 61 and the front firewall 41. Its structure is single and cannot decompose the multi-directional complex loads at the mounting joint position, so it will lead to insufficient fatigue performance of the mounting joint, affect its stability, and ultimately shorten its service life.

[0152] As a preferred technical solution of the present invention, the front end of the left suspension point lower pull rod 70 is hinged to the first joint 63, and the rear end is hinged to the fourth joint 66;

[0153] The front end of the left suspension point upper pull rod 71 is hinged to the first joint 63, and the rear end is hinged to the fifth joint 67;

[0154] The front end of the upper suspension point left pull rod 72 is hinged to the second joint 64, and the rear end is hinged to the fifth joint 67;

[0155] The front end of the upper suspension point right pull rod 73 is hinged to the second joint 64, and the rear end is hinged to the sixth joint 68;

[0156] The front end of the right suspension point upper pull rod 74 is hinged to the third joint 65, and the rear end is hinged to the sixth joint 68;

[0157] The front end of the right suspension point lower pull rod 75 is hinged to the third joint 65, and the rear end is hinged to the seventh joint 69.

[0158] Since the installation accuracy requirements for the pull rod system 62 of the installation section are relatively high, the traditional cantilever beam structure uses a welding method to connect the two ends of the cantilever beam to the installation frame 61 and the firewall respectively. There are geometric tolerances during actual processing, and the geometric tolerances accumulate after welding multiple groups of cantilever beams, resulting in relatively large internal stresses in the installation section and fatigue during actual service. In the present utility model, by means of hinged connection, the joints are first arranged on the installation frame 61 and the firewall, and during the installation process, the positions of each joint can be adjusted to indirectly make fine adjustments to the positions of each pull rod, reducing the internal stress.

[0159] The structure of each joint includes a base plate and an ear plate. The base plate is used to connect to the firewall or the installation frame 61. For example, the base plate of the first joint 63 is connected to the installation frame 61, and the base plate of the fourth joint 66 is connected to the firewall. The ear plate is a plate-shaped protrusion on the base plate and is used to connect to the end of each pull rod through bolts.

[0160] In the current technical solution of the present utility model, the axial direction of the bolts used to connect the front ends of the left suspension point lower pull rod 70 and the left suspension point upper pull rod 71 to the first joint 63 is set to the horizontal direction. When the axial direction of the bolts is the vertical direction, during the installation of the bolts when connecting the front ends of the left suspension point lower pull rod 70 and the left suspension point upper pull rod 71 to the first joint 63, there will be spatial interference. To avoid the above technical problems, the ear plate on the first joint 63 used to connect to the left suspension point lower pull rod 70 and the left suspension point upper pull rod 71 is set to the vertical direction, so that the plane where the ear plate is located is a vertical plane, which is convenient for drilling holes on the ear plate, and there will be no spatial interference problem when connecting the front end ear plates of the left suspension point lower pull rod 70 and the left suspension point upper pull rod 71 through bolts.

[0161] Since there is a third firewall strengthening beam 78 between the fourth joint 66 and the fifth joint 67, for the convenience of force conduction, the axial direction of the bolts connecting the rear end of the left suspension point lower pull rod 70 to the fourth joint 66 is the horizontal direction, and the axial direction of the bolts connecting the rear end of the left suspension point upper pull rod 71 to the fifth joint 67 is the horizontal direction.

[0162] To achieve the shear resistance function of the pull rod system 62, the bolts at the front and rear ends of the upper suspension point left pull rod 72 and the upper suspension point right pull rod 73 are both set to the vertical direction.

[0163] When the axial direction of the bolt connecting the rear end of the upper suspension point left pull rod 72 to the fifth joint 67 is the horizontal direction, the ear plate on the fifth joint 67 should face the direction of the third joint 65, and the plane where the ear plate is located should be a vertical plane, so that the ear plate on the fifth joint 67 forms a certain angle with the base plate on the fifth joint 67. When bearing the load, corresponding loads will be generated, and fatigue will occur at the angle position between the ear plate and the joint, affecting the life of the joint.

[0164] When the bolts connecting the rear end of the upper suspension point left tie rod 72 to the fifth joint 67 are set in the vertical direction, the plane where the lug on the fifth joint 67 is located is in the horizontal direction, and fatigue will not occur at the angle position between the lug and the joint when bearing the load.

[0165] As a preferred technical solution of the present utility model, the front end and the rear end of the left suspension point lower tie rod 70 are respectively hinged to the first joint 63 and the fourth joint 66 by bolts. The axial directions of the bolts provided at the front end and the rear end of the left suspension point lower tie rod 70 are in the transverse direction, and the specific transverse direction is the direction parallel to the horizontal plane.

[0166] The front end and the rear end of the left suspension point upper tie rod 71 are respectively hinged to the first joint 63 and the fifth joint 67 by bolts. The axial directions of the bolts provided at the front end and the rear end of the left suspension point upper tie rod 71 are in the transverse direction, and the specific transverse direction is the direction parallel to the horizontal plane.

[0167] The front end and the rear end of the upper suspension point left tie rod 72 are respectively hinged to the second joint 64 and the fifth joint 67 by bolts. The axial directions of the bolts provided at the front end and the rear end of the upper suspension point left tie rod 72 are in the vertical direction, and the specific vertical direction is the direction perpendicular to the horizontal plane.

[0168] The front end and the rear end of the upper suspension point right tie rod 73 are respectively hinged to the second joint 64 and the sixth joint 68 by bolts. The axial directions of the bolts provided at the front end and the rear end of the upper suspension point right tie rod 73 are in the vertical direction, and the specific vertical direction is the direction perpendicular to the horizontal plane.

[0169] The front end and the rear end of the right suspension point upper tie rod 74 are respectively hinged to the third joint 65 and the sixth joint 68 by bolts. The axial directions of the bolts provided at the front end and the rear end of the right suspension point upper tie rod 74 are in the transverse direction, and the specific transverse direction is the direction parallel to the horizontal plane.

[0170] The front end and the rear end of the right suspension point lower tie rod 75 are respectively hinged to the third joint 65 and the seventh joint 69 by bolts. The axial directions of the bolts provided at the front end and the rear end of the right suspension point lower tie rod 75 are in the transverse direction, and the specific transverse direction is the direction parallel to the horizontal plane.

[0171] By setting the axial directions of the bolts in the transverse and vertical directions, the technical effect of resisting shear force can be achieved, preventing the technical problem that when subjected to shear force, the axial directions of all bolts are the same, and the direction of the shear force happens to be the same as the radial direction of each bolt, generating a large stress on the bolts and causing the bolts to deform, resulting in the destruction of the stability of the entire system.

[0172] The fourth joint 66 is located directly behind the first joint 63. The "directly behind" specifically refers to the positional relationship of the fourth joint 66 relative to the first joint 63, where the fourth joint 66 is located on the same horizontal plane and vertical plane as the first joint 63, and these two planes are perpendicular to each other. The "directly behind" mentioned hereinafter has the same meaning as this "directly behind". The fifth joint 67 is located directly above the fourth joint 66. The "directly above" specifically refers to the positional relationship of the fifth joint 67 relative to the fourth joint 66, where the fifth joint 67 is located on the same vertical line as the fourth joint 66. The "directly above" mentioned hereinafter has the same meaning as this "directly above". The seventh joint 69 is located directly behind the third joint 65, and the sixth joint 68 is located directly above the seventh joint 69. The sixth joint 68 is located to the right of the fifth joint 67 and at the same horizontal height.

[0173] The first joint 63, the third joint 65, the fourth joint 66, and the seventh joint 69 are located at the same horizontal height.

[0174] As a preferred technical solution of the present utility model, the tie rod system 62 further includes a first firewall reinforcing beam 76 and a second firewall reinforcing beam 77. Both the first firewall reinforcing beam 76 and the second firewall reinforcing beam 77 are riveted to the front firewall 41. The upper end of the first firewall reinforcing beam 76 is connected to the fifth joint 67, and the lower end of the first firewall reinforcing beam 76 is connected to the fourth joint 66; the upper end of the second firewall reinforcing beam 77 is connected to the sixth joint 68, and the lower end of the second firewall reinforcing beam 77 is connected to the seventh joint 69.

[0175] Since the front firewall 41 is relatively thin and the force it can bear is limited, through the setting of the first firewall reinforcing beam 76, a triangular structure can be formed with the left suspension point lower tie rod 70 and the left suspension point upper tie rod 71. The first firewall reinforcing beam 76 can conduct force instead of the front firewall 41 to prevent the front firewall 41 from deforming and enhance the overall structural stability. Similarly, the second firewall reinforcing beam 77 can form a triangular structure with the right suspension point lower tie rod 75 and the right suspension point upper tie rod 74.

[0176] Through the setting of the positions of the first joint and the fourth joint, the front end and the rear end of the left suspension point lower tie rod 70 are at the same horizontal height, making the force transmission effect between the engine and the first fireproof board better.

[0177] Through the setting of the positions of the third joint and the seventh joint, the front end and the rear end of the left suspension point lower tie rod 75 are at the same horizontal height, making the force transmission effect between the engine and the first fireproof board better

[0178] Since the fifth joint 67 is directly above the fourth joint 66, a stable force transmission path is formed among the fifth joint, the fourth joint and the first firewall reinforcing beam 76. There is no situation where the first firewall reinforcing beam is obliquely arranged, so that the force transmission direction is the same as the length direction of the first firewall reinforcing beam, improving the force transmission effect.

[0179] Since the seventh joint 69 is directly below the sixth joint 68, a stable force transmission path is formed among the seventh joint, the sixth joint and the second reinforcing beam. There is no situation where the second firewall reinforcing beam is obliquely arranged, so that the force transmission direction is the same as the length direction of the second firewall reinforcing beam, improving the force transmission effect.

[0180] As a preferred technical solution of the present utility model, it further includes a third firewall reinforcing beam 78. The third firewall reinforcing beam 78 is arranged on the front firewall 41, and the left end of the third firewall reinforcing beam 78 is connected to the fifth joint 67, and the right end is connected to the sixth joint 68.

[0181] Through the arrangement of the third firewall reinforcing beam 78, a triangular structure can be formed with the upper suspension point left pull rod 72 and the upper suspension point right pull rod 73. The third firewall reinforcing beam 78 can conduct force instead of the front firewall 41, strengthening the overall structural stability.

[0182] As a supplement to the above technical solution, the third firewall reinforcing beam 78 is arranged on the rear side surface of the front firewall 41. The left end of the fifth joint 67, the front firewall 41 and the third firewall reinforcing beam 78 are connected by a screwing method, and the right end of the sixth joint 68, the front firewall 41 and the third firewall reinforcing beam 78 are connected by a screwing method.

[0183] The third firewall reinforcing beam 78 is actually an I-beam inside the wing. Since the thickness of the front firewall 41 is relatively thin, directly connecting the fifth joint 67 and the sixth joint 68 to the firewall will cause the problem of stress deformation of the firewall. By connecting the fifth joint 67 and the sixth joint 68 to the third firewall reinforcing beam 78, while forming a stable triangular structure between the upper suspension point left pull rod 72, the upper suspension point right pull rod 73 and the third firewall reinforcing beam 78, the technical problem of firewall stress deformation is avoided.

[0184] As a preferred technical solution of the present utility model, the mounting frame 61 includes a third U-shaped frame 79, a shock pad 80 and a second adapter plate 81. The third U-shaped frame 79 is connected to the suspension point of the engine through the second adapter plate 81.

[0185] The second adapter plate 81 is a plate-like structure, and its lower end is connected to the engine by bolts. A shock pad 80 is respectively arranged on both sides of the upper part of the second adapter plate 81. The shock pad 80, the adapter plate and the third U-shaped frame 79 are connected by bolts.

[0186] The above are only the preferred specific embodiments of the present utility model, but the protection scope of the present utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present utility model, according to the technical solution and inventive concept of the present utility model, makes equivalent substitutions or changes, and should be covered within the protection scope of the present utility model.

Claims

1. An engine nacelle, characterized in that, It includes a front firewall (41), an upper firewall (43), a rear firewall (42), a front section skin, a middle section skin, a rear section skin (84), and a mounting frame (61); The front firewall (41) and the rear firewall (42) are arranged relatively parallel. A first through hole (44) is provided on the front firewall (41), and a second through hole (45) is provided on the rear firewall (42); The upper firewall (43) is arranged between the front firewall (41) and the rear firewall (42). The front end of the upper firewall (43) is connected to the front firewall (41), and the rear end is connected to the rear firewall (42); The mounting frame (61) is a U-shaped structure with an opening downward, located on the front side of the front firewall (41) and connected to the front firewall (41); The front section skin includes a front upper wall panel (1), an air intake lip (2), a front lower wall panel (3), and a U-shaped reinforcing beam (20). The U-shaped reinforcing beam (20) is a U-shaped beam with an opening upward. The left free end of the mounting frame (61) is connected to the left free end of the U-shaped reinforcing beam (20), and the right free end of the mounting frame (61) is connected to the right free end of the U-shaped reinforcing beam (20); The front upper wall panel (1) is located above the air intake lip (2) and the front lower wall panel (3). The air intake lip (2) is located on the front side of the front lower wall panel (3). The upper ends of the air intake lip (2) and the front lower wall panel (3) are both connected to the lower end of the front upper wall panel (1). The front end of the front lower wall panel (3) is connected to the rear end of the air intake lip (2). The rear end of the front upper wall panel (1) is connected to the mounting frame (61), and the rear end of the front lower wall panel (3) is connected to the U-shaped reinforcing beam (20); The middle section skin includes a middle upper wall panel (16), a middle left wall panel (17), a middle right wall panel (18), a left cabin door panel (36), and a right cabin door panel (37). The right end of the middle left wall panel (17) is connected to the left end of the middle upper wall panel (16), and the left end of the middle right wall panel (18) is connected to the right end of the middle upper wall panel (16). The front ends of the middle left wall panel (17), the middle right wall panel (18), and the middle upper wall panel (16) are all connected to the mounting frame (61). The rear end of the middle upper wall panel (16) is connected to the front firewall (41), and the rear ends of the middle left wall panel (17) and the middle right wall panel (18) are connected to the rear firewall (42). The inner surface of the middle left wall panel (17) abuts against the left ends of the front firewall (41) and the upper firewall (43), and the inner surface of the middle right wall panel (18) abuts against the right ends of the front firewall (41) and the upper firewall (43); The upper end of the left cabin door panel (36) is connected to the lower end of the middle left wall panel (17) through a hinge, and the upper end of the right cabin door panel (37) is connected to the lower end of the middle right wall panel (18) through a hinge; The rear section skin (84) is arranged at the rear side of the middle section skin, and the front end of the rear section skin (84) is connected to the rear firewall (42).

2. The short nacelle of an engine according to claim 1, characterized in that, The front firewall (41) includes an upper fireproof plate (46), a lower fireproof plate (47), side reinforcing ribs (48), a first arc-shaped reinforcing rib (49), and a second arc-shaped reinforcing rib (50). Semi-circular notches are provided at the lower part of the upper fireproof plate (46) and the upper part of the lower fireproof plate. The lower end of the upper fireproof plate (46) is connected to the upper end of the lower fireproof plate (47). The semi-circular notches of the upper fireproof plate (46) and the lower fireproof plate (47) form a first through hole (44). A protruding portion (51) is provided at the lower end of the upper fireproof plate (46). The protruding portion (51) is a plate-like structure extending downward at the lower end position of the upper fireproof plate (46). The protruding portion (51) of the upper fireproof plate (46) is located at the rear side of the lower fireproof plate (47), and the protruding portion (51) of the upper fireproof plate (46) is connected to the lower fireproof plate (47). The first arc-shaped reinforcing rib (49) is arranged at the circumferential position of the lower semi-circular notch of the upper fireproof plate (46), and the second arc-shaped reinforcing rib (50) is arranged at the circumferential position of the upper semi-circular notch of the lower fireproof plate (47). The side reinforcing ribs (48) are arranged on the surface of the upper fireproof plate (46). There are two groups of side reinforcing ribs (48). The first side reinforcing rib is arranged on the left part of the upper fireproof plate (46), and the second side reinforcing rib is arranged on the right part of the upper fireproof plate (46). Flanges are provided at the side edges of the first side reinforcing rib and the second side reinforcing rib. The first side reinforcing rib abuts against the middle left wall plate (17) of the middle skin through its flange, and the second side reinforcing rib abuts against the middle right wall plate (18) of the middle skin through its flange.

3. The engine nacelle according to claim 2, characterized in that, It further includes a reinforcing connecting rod (52), an eighth joint (53), a ninth joint (54), and a third reinforcing beam (55). The front end of the reinforcing connecting rod (52) is connected to the front firewall (41), and the rear end of the reinforcing connecting rod (52) is connected to the rear firewall (42). There are two groups of the reinforcing connecting rods (52) in total. The position where the first reinforcing connecting rod is connected to the front firewall (41) is on the left side of the first through hole (44), and the position where the first reinforcing connecting rod is connected to the rear firewall (42) is on the left side of the second through hole (45). The position where the second reinforcing connecting rod is connected to the front firewall (41) is on the right side of the first through hole (44), and the position where the second reinforcing connecting rod is connected to the rear firewall (42) is on the right side of the second through hole (45). The front ends of the two reinforcing connecting rods (52) are both connected to the front firewall (41) through the eighth joint (53), and the rear ends of the two reinforcing connecting rods (52) are both connected to the rear firewall (42) through the ninth joint (54). The reinforcing connecting rod (52) is hingedly connected to the eighth joint (53) and the ninth joint (54). A third reinforcing beam (55) is provided between the ninth joints (54) at the rear ends of the two reinforcing connecting rods (52).

4. An engine nacelle according to claim 3, characterized in that, The upper firewall (43) includes an upper fireproof board (56), corner beams (57), U-shaped beams (58), and an engine rear suspension point mounting box (59). Both left and right ends of the upper fireproof board (56) are provided with flanges. The left end of the upper fireproof board (56) is connected to the middle left wall panel (17) of the middle section skin, and the right end of the upper fireproof board (56) is connected to the middle right wall panel (18) of the upper firewall (43). The corner beam (57) is an L-shaped long beam with a cross-section composed of two mutually perpendicular plates. The horizontal plate of the corner beam (57) is riveted to the upper fireproof board (56), and the vertical plate of the corner beam (57) is connected to the front firewall (41). The U-shaped beam (58) includes a top plate, a bottom plate, and a web. The top plate and the bottom plate are connected by a vertically arranged web. The bottom plate of the U-shaped beam (58) is connected to the upper firewall (43), and the web is connected to the rear firewall (42). A vertically opened through hole is provided on the upper fireproof board (56). The lower bottom surface of the engine rear suspension point mounting box (59) is provided with a groove. The engine rear suspension point mounting box (59) is located above the through hole on the upper fireproof board (56), and the lower end of the engine rear suspension point mounting box (59) is connected to the upper fireproof board (56). The connection position of the engine rear suspension point mounting box (59) and the upper fireproof board (56) is located on the outer periphery of the through hole on the upper fireproof board (56), so that the through hole on the upper fireproof board (56) is communicated with the inner space of the groove of the engine rear suspension point mounting box (59).

5. An engine nacelle according to claim 1, characterized in that, The front section skin further includes an elastic sealing strip (10). The air intake lip (2) includes a lip skin (4), a web member (5), and a first U-shaped frame (6). The web member (5) is riveted to the inner side of the lip skin (4) and is located at the rear of the lip skin (4). A plate-shaped flange (7) is provided on the side of the web member (5) close to the lip skin (4). The plate-shaped flange (7) is connected to the lip skin (4) by a quick-release lock. The first U-shaped frame (6) is arranged on the web member (5) and there is a gap between the first U-shaped frame (6) and the plate-shaped flange (7) on the web member (5). The front section lower wall panel (3) includes a front section lower wall panel skin (8) and a second U-shaped frame (9). The second U-shaped frame (9) is riveted to the front end of the front section lower wall panel skin (8). The front end face of the second U-shaped frame (9) is a flat plate surface, and the width of the front end face of the second U-shaped frame (9) is greater than the distance between the first U-shaped frame (6) and the plate-shaped flange (7). The second U-shaped frame (9) abuts against the plate-shaped flange (7) on the web member (5) and the first U-shaped frame (6). The second U-shaped frame (9), the web member (5), the plate-shaped flange (7), and the first U-shaped frame (6) enclose a U-shaped belt-shaped space with a rectangular cross-section. The elastic sealing strip (10) is arranged in the U-shaped belt-shaped space. The second U-shaped frame (9) squeezes the elastic sealing strip (10), causing the elastic sealing strip to undergo compressive deformation to fill the U-shaped belt-shaped space.

6. An engine nacelle according to claim 5, characterized in that, The front upper wall panel (1) includes a front upper wall panel skin (11) and upper wall panel stiffeners (12). The upper wall panel stiffeners (12) are arranged on the inner side of the upper wall panel and riveted to the front upper wall panel skin (11). The air inlet lip further includes a first connecting backing plate (13). The lower part of the first connecting backing plate (13) is located inside the lip skin (4) and connected to the lip skin (4). The upper part of the first connecting backing plate (13) protrudes above the upper edge of the lip skin (4) and is located inside the front upper wall panel skin (11). The upper part of the first connecting backing plate (13) is connected to the front upper wall panel skin (11) through a quick-release lock. The front lower wall panel (3) further includes a second connecting backing plate (14). The lower part of the second connecting backing plate (14) is located inside the front lower wall panel skin (8) and connected to the front lower wall panel skin (8). The upper part of the second connecting backing plate (14) protrudes above the upper edge of the front lower wall panel skin (8) and is located inside the front upper wall panel skin (11). The second connecting backing plate (14) is connected to the front upper wall panel skin (11) through a quick-release lock.

7. An engine nacelle according to claim 1, characterized in that, The middle section skin further includes a tail cross beam (82) and a mounting beam (19). The left middle wall panel (17) includes a left middle wall panel skin (22) and a first connecting plate (23). The first connecting plate (23) is arranged on the lower surface of the left middle wall panel skin (22) through rivets. The right part of the first connecting plate (23) protrudes beyond the right end of the left middle wall panel skin (22) and extends below the middle upper wall panel skin (21), and is connected to the middle upper wall panel skin (21) through a quick-release lock. The right middle wall panel (18) includes a right middle wall panel skin (24) and a second connecting plate (25). The second connecting plate (25) is arranged on the lower surface of the right middle wall panel skin (24) through rivets. The left part of the second connecting plate (25) protrudes beyond the left end of the right middle wall panel skin (24) and extends below the middle upper wall panel skin (21), and is connected to the middle upper wall panel skin (21) through a quick-release lock. The mounting beam (19) is arranged on the mounting frame (61) and is located below the middle upper wall panel skin (21), the left middle wall panel skin (22), and the right middle wall panel skin (24). The front ends of the middle upper wall panel skin (21), the left middle wall panel skin (22), and the right middle wall panel skin (24) are all connected to the mounting beam (19) through quick-release locks. The tail cross beam (82) is riveted to the front firewall (41), and the rear end of the middle upper wall panel (16) is connected to the tail cross beam (82) through a quick-release lock.

8. An engine nacelle according to claim 7, characterized in that, The middle upper wall panel (16) further includes upper wall panel longitudinal beams and upper wall panel cross beams. There are three groups of upper wall panel longitudinal beams, namely the first longitudinal beam (26), the second longitudinal beam (27), and the third longitudinal beam (28). The three groups of upper wall panel longitudinal beams are arranged on the lower bottom surface of the middle upper wall panel skin (21) from left to right in sequence and are all connected to the middle upper wall panel skin (21) through rivets. The upper wall panel cross beam includes a first short beam (29) and a second short beam (30). The left end of the first short beam (29) is connected to the first longitudinal beam (26), and the right end of the first short beam (29) is connected to the second longitudinal beam (27). The left end of the second short beam (30) is connected to the second longitudinal beam (27), and the right end of the second short beam (30) is connected to the third longitudinal beam (28).

9. The short nacelle of an engine according to claim 1, characterized in that, It further includes a tie rod system (62). The tie rod system (62) includes a first joint (63), a second joint (64), a third joint (65), a fourth joint (66), a fifth joint (67), a sixth joint (68), a seventh joint (69), a left suspension point lower tie rod (70), a left suspension point upper tie rod (71), an upper suspension point left tie rod (72), an upper suspension point right tie rod (73), a right suspension point lower tie rod (75), and a right suspension point upper tie rod (74). Among them, the first joint (63), the second joint (64), and the third joint (65) are arranged on the mounting frame (61). The first joint (63) is located at the left end of the mounting frame (61), the second joint (64) is located at the upper end of the mounting frame (61), and the third joint (65) is located at the right end of the mounting frame (61). The fourth joint (66), the fifth joint (67), the sixth joint (68), and the seventh joint (69) are arranged on the front firewall (41). The fourth joint (66) is directly behind the first joint (63), the fifth joint (67) is directly above the fourth joint (66), the seventh joint (69) is directly behind the third joint (65), the sixth joint (68) is directly above the seventh joint (69), the sixth joint (68) is to the right of the fifth joint (67), and the sixth joint (68) and the fifth joint (67) are at the same horizontal height. A left suspension point lower tie rod (70) is connected between the first joint (63) and the fourth joint (66), and a left suspension point upper tie rod (71) is connected between the first joint (63) and the fifth joint (67). An upper suspension point left tie rod (72) is connected between the second joint (64) and the fifth joint (67), and an upper suspension point right tie rod (73) is connected between the second joint (64) and the sixth joint (68). A right suspension point upper tie rod (74) is connected between the third joint (65) and the sixth joint (68), and a right suspension point lower tie rod (75) is connected between the third joint (65) and the seventh joint (69).

10. The short nacelle of an engine according to claim 9, characterized in that, The tie rod system (62) further includes a first firewall reinforcing beam (76), a second firewall reinforcing beam (77), and a third firewall reinforcing beam (78). The upper end of the first firewall reinforcing beam (76) is connected to the fifth joint (67), and the lower end of the first firewall reinforcing beam (76) is connected to the fourth joint (66). The upper end of the second firewall reinforcing beam (77) is connected to the sixth joint (68), and the lower end of the second firewall reinforcing beam (77) is connected to the seventh joint (69). The third firewall reinforcing beam (78) is disposed on the rear side surface of the front firewall (41). The left end of the third firewall reinforcing beam (78) is connected to the fifth joint (67), and the right end is connected to the sixth joint (68).

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