External water throwing cabin door structure of airplane mechanism and airplane

Abstract

The invention discloses an external water throwing cabin door structure of an airplane mechanism and an airplane, and belongs to the field of airplane structure design. The water throwing cabin door is arranged on the lower portion of the airplane belly. The door frame is fixed to a discharge outlet outside an aircraft body, an annular sealing belt is arranged on the lower surface of the discharge outlet, a cabin door lifting mechanism and a locking mechanism mounting connector are arranged on the door frame, one side of the water throwing cabin door is hinged to the aircraft body through a suspension hinge, and a cabin door body is buckled to the sealing belt of the discharge outlet. The water throwing cabin door is provided with a lifting mechanism, the two ends of the cabin door are connected with the lifting mechanism through lugs, and the lifting mechanism comprises a damping pull rod and has the functions of quick opening, buffering, self-locking and self-locking relieving. The water throwing cabin door is provided with a locking mechanism, the other side of the cabin door is connected with a locking groove in the locking mechanism through a lock pin connector, and the locking mechanism comprises a cam and a pre-position spring and has the function of preventing accidental opening. The cabin door suspension hinge, the lifting mechanism and the locking mechanism are arranged on the outer side of the cabin door sealing area at the discharge opening and on the inner side of the fuselage rectification appearance.

Description

Technical Field

[0001] The present application belongs to the field of aircraft structure design, and relates to an aircraft mechanism external water-dropping hatch structure and an aircraft. Background Art

[0002] Forest fires are sudden, destructive, and dangerous. They are one of the most frequent, difficult to deal with, and most serious natural disasters in the world. The damage to the global environment and economy is immeasurable. The prevention and fighting of forest fires has become the focus of global attention. In order to meet the country's urgent need for forest aviation firefighting equipment, it is necessary to discharge fire extinguishing media in the air by aircraft to achieve tasks such as forest fire fighting. In order to ensure that the fire extinguishing medium can be accurately delivered to the fire area according to the expected delivery task, it is necessary to set up corresponding storage and discharge devices to ensure that the fire extinguishing medium can be effectively stored in the aircraft before delivery, and when it is needed, the fire extinguishing medium can be discharged quickly, stably, and reliably.

[0003] The structural design of the water-dropping hatch is the core of the fire extinguisher's function of releasing the fire extinguishing medium. It is required to be able to discharge the liquid fire extinguishing medium outside the aircraft body. It should be a functional hatch that is sealed, load-bearing, quick-opening, lightweight and corrosion-resistant. The design difficulties lie in the following aspects: First, the door structure of the water-dropping hatch provides the function of carrying and transporting the fire extinguishing medium as part of the storage device, and the door body needs to withstand the impact of the fire extinguishing medium when performing the release function. The water-dropping hatch must meet the strength and rigidity requirements. Second, when the water-dropping hatch performs the water-dropping operation, the design of the lifting mechanism requires the functions of quick opening, buffering and self-locking retention, and the lifting mechanism requires the function of releasing the self-locking when the hatch is closed. Third, the water-dropping hatch is dangerous when the fire extinguishing medium is discharged, so the locking function of the locking mechanism is required to be stable and reliable, and accidental opening cannot occur at any time. Fourth, the water-dropping hatch not only requires its own structural sealing, but also requires good sealing performance between it and the fire extinguishing medium discharge port. Fifth, the water-dropping hatch movement mechanism requires high installation accuracy to ensure the coordination of the hatch movement. Sixth, electrochemical corrosion will occur when the structure and mechanism of the water-dropping hatch come into contact with the fire-extinguishing medium, so anti-corrosion measures must be considered to the greatest extent possible. Summary of the invention

[0004] The purpose of the present application is to solve the problems in the prior art and to provide an aircraft mechanism external water-dropping hatch structure and an aircraft, which can effectively meet the requirements that the liquid fire-extinguishing medium water-dropping hatch should have the characteristics of sealing, load-bearing, quick opening, lightweight and corrosion resistance, and realize the storage, transportation and delivery functions of the fire-extinguishing medium on the aircraft.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions: In the first aspect, the present application provides an external flood hatch structure of an aircraft mechanism, including a flood hatch and a door frame, wherein the flood hatch is mounted on the door frame, and the door frame is used to fix the flood hatch; a hanging hinge joint is provided on one side of the flood hatch, and a lifting structure and a locking mechanism are provided on the other side, and the other side of the flood hatch is engaged with a lock groove on the locking mechanism through a lock pin joint.

[0006] Furthermore, both ends of the flooding hatch of the present application are connected to the lifting mechanism through ears.

[0007] Furthermore, the lifting mechanism of the present application includes a transmission shaft, a damping rod and a driven rod. The transmission shaft is fixed on the door frame, one end of the damping rod is fixedly connected to both ends of the transmission shaft, and the other end is hinged to the driven rod. The driven rod is connected to the flooding door through an ear piece. The lifting mechanism has the functions of quick opening, buffering, self-locking and releasing self-locking.

[0008] Furthermore, the door frame of the present application is provided with installation interfaces for the hatch lifting mechanism and the locking mechanism.

[0009] Furthermore, the hatch door locking mechanism of the present application includes a push rod shaft, a cam and a pre-position spring. The push rod shaft is fixed on the door frame, the cam is fixedly connected to the push rod shaft, one end of the lock groove is embedded in the cam slide groove, and the other end is engaged with the lock pin joint on the flooding hatch. The locking mechanism has the function of preventing accidental opening.

[0010] Furthermore, the flooding door of the present application is an inverted integral machined structural component, and a locking pin joint is arranged on the door body structure of the flooding door.

[0011] Furthermore, the water-dropping door, suspension hinge, lifting mechanism and locking mechanism of the present application are all arranged on the outside of the door sealing area at the discharge port and on the inside of the fuselage fairing shape to prevent the movable parts of the water-dropping door from being immersed in the liquid fire-extinguishing medium.

[0012] In the second aspect, the present application provides an aircraft, including an aircraft body and a discharge port opened in the belly of the aircraft body, a door frame is installed at the discharge port, four water-dropping hatches are installed on the outside of the discharge port through the door frame, and an annular sealing belt is provided on the lower surface of the discharge port; one side of the water-dropping hatch is hinged to the aircraft body through a hanging hinge joint, and the water-dropping hatch is buckled on the sealing belt of the discharge port.

[0013] Furthermore, the sealing belt of the present application is fixed to the lower surface of the discharge port by a sealing belt pressure piece. The sealing belt has a C-shaped cross-section. The flood hatch is buckled on the sealing belt. The lower surface of the sealing belt is squeezed by the flood hatch, and the upper surface is subjected to water pressure.

[0014] Furthermore, a fuselage fairing is provided around the water-dropping hatch of the present application to maintain the aerodynamic shape of the aircraft when the water-dropping hatch is closed and to seal the fire-extinguishing medium in the water tank.

[0015] Compared with the prior art, this application has the following beneficial effects: The aircraft mechanism external water-dropping hatch structure provided in this application, the design of the water-dropping hatch and door frame, and the integration of the suspension hinge joint, lifting structure and locking mechanism make the entire structure compact and have multiple functions (such as quick opening, buffering, self-locking, releasing self-locking and preventing accidental opening, etc.), meeting the aircraft's rapid response needs in emergency situations. The design of the entire water-dropping hatch structure takes into account the aircraft's aerodynamic performance and safety. This application has a large-sized hatch with the characteristics of sealing, load-bearing, quick opening, lightweight and corrosion resistance. The lifting mechanism can achieve buffering and self-locking when the hatch is open, and the locking mechanism can achieve accidental opening prevention when the hatch is closed. The hatch load-bearing and launching functions are stable and reliable.

[0016] Furthermore, the design of the lifting mechanism of the present application, especially the combination of the transmission shaft, the damping rod and the driven rod, enables the hatch to be opened and closed smoothly and quickly, improving the convenience and safety of operation. At the same time, the self-locking and unlocking functions also enhance the stability of the hatch during use.

[0017] Furthermore, the combined design of the push rod shaft, cam and pre-position spring in the door locking mechanism of the present application ensures that the door is tightly locked in the closed state, preventing accidental opening, thereby ensuring the sealing of the fire extinguishing medium. In addition, the fuselage fairing arranged around the water-dropping door can maintain the aerodynamic shape of the aircraft when the door is closed, and further seal and protect the fire extinguishing medium in the water tank.

[0018] Furthermore, the present application effectively avoids the immersion of the movable parts of the water-dropping door in the liquid fire-extinguishing medium by arranging the water-dropping door, suspension hinge, lifting mechanism and locking mechanism on the outside of the door sealing area at the discharge port and on the inside of the fuselage fairing shape, thereby extending the service life of the parts and reducing maintenance costs.

[0019] The aircraft provided in the present application not only has all the advantages of the external flood hatch structure of the above-mentioned aircraft mechanism, but also the design of its sealing belt not only improves the sealing effect, but also through its C-shaped cross-section and the buckling method of the flood hatch, the lower surface of the sealing belt is squeezed by the flood hatch and the upper surface is subjected to water pressure, thereby enhancing the overall sealing and pressure-bearing capacity.

[0020] Furthermore, the fairing of the aircraft fuselage of the present application is used to maintain the aerodynamic shape of the aircraft during flight, reduce resistance, and improve flight efficiency. Since the water-dropping hatch is an inverted integral machined structural part, and the connection method between the various components is simple and clear, it is easy to maintain and replace in actual use, reducing the maintenance cost and time cost of the aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 This is the layout diagram of the external motion mechanism of the flood hatch.

[0023] Figure 2 This is a schematic diagram of the structure of the flood hatch door.

[0024] Figure 3 Schematic diagram of the lifting mechanism of the water-dropping hatch.

[0025] Figure 4 Schematic diagram of the locking mechanism of the flood hatch.

[0026] Figure 5 Schematic diagram of the sealing structure of the water-dropping hatch and the discharge port.

[0027] Figure 6 This is a schematic diagram of the layout of the flooding hatch and surrounding structures.

[0028] Figure 7 This is a schematic diagram of the closed state of the water-dropping hatch and the fairing structure.

[0029] Explanation of numbers in the figure: 1 aircraft body, 2 door frame, 3 water-dropping door, 4 lifting mechanism, 5 locking mechanism, 6 discharge port, 7 suspension hinge, 8 door structure, 9 lock pin joint, 10 ear piece, 11 transmission shaft, 12 damping rod, 13 driven rod, 14 push rod shaft, 15 cam, 16 pre-position spring, 17 lock groove, 18 sealing belt, 19 sealing belt pressure piece, 20 fairing. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0031] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0032] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0033] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the invented product is usually placed when used. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0034] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0035] In the description of the embodiments of the present application, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0036] The water-dropping hatch structure of this embodiment is installed on the lower part of the belly of a certain type of aircraft, and together with the water tank, discharge channel and trim pipe in the aircraft cabin, it forms a fire-extinguishing medium storage device with a target loading capacity of 6 tons. The device is designed with 4 storage water tanks, and the discharge port at the bottom of each water tank is equipped with a water-dropping hatch. These hatches not only provide storage and transportation functions for fire-extinguishing media, but also can quickly drop fire-extinguishing media when needed, with a target discharge time of 2 to 4 seconds.

[0037] The present application is further described in detail below with reference to the accompanying drawings: See also Figure 1The embodiment of the present application discloses an aircraft mechanism external water-dropping hatch structure, comprising a water-dropping hatch 3 and a door frame 2, wherein the water-dropping hatch 3 is mounted on the door frame 2, and the door frame 2 is used to fix the water-dropping hatch 3; a hanging hinge joint is provided on one side of the water-dropping hatch 3, and a lifting structure 4 and a locking mechanism 5 are provided on the other side, and the other side of the water-dropping hatch 3 is engaged with a lock groove 17 on the locking mechanism 5 through a lock pin joint 9. The door frame 2 is provided with mounting interfaces for the hatch lifting mechanism 4 and the locking mechanism 5.

[0038] In practical applications, the flooding hatch 3 and the door frame 2 of the present application are the main parts of the structure. The door frame 2 is firmly fixed to the discharge port 6 outside the aircraft body 1, and a ring-shaped sealing belt 18 is provided on the lower surface of the discharge port 6. The door frame 2 is provided with installation interfaces for the hatch lifting mechanism 4 and the locking mechanism 5 so that these mechanisms can be installed in place.

[0039] like Figure 2 As shown, in a feasible embodiment, one side of the flooding hatch 3 is hinged to the aircraft body 1 through a hanging hinge joint, so that it can rotate around the hinge. The door body structure 8 of the hatch is an inverted integral machined structural member, which has the characteristics of high strength, high rigidity and light weight. A lock pin joint 9 is arranged on the other side of the flooding hatch 3 for engaging with the locking mechanism 5. At the same time, ears 10 are also arranged at both ends of the hatch for connecting with the lifting mechanism 4.

[0040] The lifting mechanism 4 includes a transmission shaft 11, a damping rod 12 and a driven rod 13. The transmission shaft 11 is fixed on the door frame 2. One end of the damping rod 12 is fixedly connected to both ends of the transmission shaft 11, and the other end is hinged to the driven rod 13. The driven rod 13 is connected to the flooding door 3 through an ear piece 10. The lifting mechanism 4 has the functions of quick opening, buffering, self-locking and releasing self-locking.

[0041] like Figure 3 As shown, in actual application, the lifting mechanism 4 is a key component for the rapid opening of the flood hatch. It includes a transmission shaft 11, a damping rod 12 and a driven rod 13. The transmission shaft 11 is fixed to the door frame 2, one end of the damping rod 12 is fixedly connected to both ends of the transmission shaft 11, and the other end is hinged to the driven rod 13. The driven rod 13 is connected to the flood hatch 3 through the ear piece 10. The lifting mechanism 4 has the functions of quick opening, buffering, self-locking and unlocking, ensuring that the hatch can be opened and closed quickly and smoothly when needed.

[0042] The door locking mechanism 5 includes a push rod shaft 14, a cam 15 and a pre-position spring 16. The push rod shaft 14 is fixed on the door frame 2, and the cam 15 is fixedly connected to the push rod shaft 14. One end of the lock groove 17 is embedded in the slide groove of the cam 15, and the other end is engaged with the lock pin joint 9 on the flooding door 3. The locking mechanism 5 has the function of preventing accidental opening.

[0043] like Figure 4and Figure 5 As shown, in actual application, the locking mechanism 5 is an important component to ensure that the flooding door is safely locked in the closed state. It includes a push rod shaft 14, a cam 15 and a pre-position spring 16. The push rod shaft 14 is fixed to the door frame 2, and the cam 15 is fixedly connected to the push rod shaft 14. One end of the lock groove 17 is embedded in the slide groove of the cam 15, and the other end is engaged with the lock pin joint 9 on the flooding door 3. The locking mechanism 5 has the function of preventing accidental opening, ensuring that the door will not be accidentally opened due to external factors during flight.

[0044] The water-dropping door 3 is an inverted integral machined structural part, and a lock pin joint 9 is arranged on the door structure 8 of the water-dropping door 3. The water-dropping door 3, the suspension hinge 7, the lifting mechanism 4 and the locking mechanism 5 are all arranged outside the door sealing area at the discharge port 6 and inside the fuselage fairing shape to prevent the movable parts of the water-dropping door 3 from being immersed in the liquid fire extinguishing medium.

[0045] See also Figure 6-Figure 7 The present embodiment is an external water-dropping door for discharging liquid fire-extinguishing medium on an aircraft. A water-dropping door is designed with a certain type of aircraft as a carrier aircraft, and is combined with a water tank, a discharge channel and a balancing pipe in the aircraft cabin to form a fire-extinguishing medium storage device with a target loading capacity of 6 tons and a target discharge time of 2 to 4 seconds. The aircraft is equipped with 4 storage water tanks, and a water-dropping door 3 is provided at a discharge port 6 at the bottom of the water tank to provide storage, transportation and delivery functions for the fire-extinguishing medium in the aircraft cabin.

[0046] Specifically, the present embodiment provides an aircraft, comprising an aircraft body 1 and a discharge port 6 opened at the belly of the aircraft body 1, a door frame 2 is installed at the discharge port 6, four water-dropping hatches 3 are installed on the outside of the discharge port 6 through the door frame 2, and an annular sealing belt 18 is provided on the lower surface of the discharge port 6; one side of the water-dropping hatch 3 is hinged to the aircraft body 1 through a hanging hinge joint, and the water-dropping hatch 3 is buckled on the sealing belt 18 of the discharge port 6.

[0047] In a feasible embodiment, the sealing belt 18 is fixed to the lower surface of the discharge port 6 by a sealing belt pressing piece 19. The sealing belt 18 has a C-shaped cross-section. The flood hatch 3 is buckled on the sealing belt 18. The lower surface of the sealing belt 18 is squeezed by the flood hatch 3, and the upper surface is subjected to water pressure.

[0048] In practical applications, the sealing belt 18 is a key component to ensure the sealing of the flooding hatch. It is fixed to the lower surface of the discharge port 6 through the sealing belt pressing piece 19 and has a C-shaped cross section. When the flooding hatch 3 is closed, it is buckled on the sealing belt 18. The lower surface of the sealing belt 18 is squeezed by the hatch, and the upper surface is subjected to water pressure. This design not only ensures the sealing of the hatch, but also makes the sealing effect better the more fire extinguishing medium is installed.

[0049] In the present application, a fuselage fairing 20 is arranged around the water-dropping door 3, and the aerodynamic shape of the aircraft is maintained when the water-dropping door 3 is closed, and the fire-extinguishing medium in the water tank is sealed. The four water-dropping doors 3 are respectively arranged in the discharge port 6 area of ​​the belly of the aircraft body 1. The fuselage fairing 20 is arranged around the water-dropping door 3, and the aerodynamic shape of the aircraft is maintained when the door is closed, and the fire-extinguishing medium in the water tank is sealed. When opened, it opens downward and outward to realize the discharge of the fire-extinguishing medium.

[0050] In practical applications, a fuselage fairing 20 is also provided around the water-dropping hatch 3. When the hatch is closed, the fairing can maintain the aerodynamic shape of the aircraft and reduce flight resistance. At the same time, it can also seal and protect the fire extinguishing medium in the water tank to prevent leakage of the medium.

[0051] How this application works: When the flooding hatch 3 is in a closed state, the four hanging hinges 7 on one side of the hatch and the four locking pin joints 9 engaged with the locking groove 17 on the other side together form four constraints to lock the hatch, and the flooding hatch 3 squeezes the sealing tape 18 on the discharge port 6 to achieve the sealing of the fire extinguishing medium.

[0052] When executing the water-dropping operation function, the push rod shaft 14 on the locking mechanism 5 is fixedly connected to the cam 15 to make a linear motion, driving the lock slot 17 to rotate and disengage from the lock pin joint 9 to achieve unlocking, and the water-dropping hatch 3 rotates around the suspension hinge 7 to open outward and downward, and the lifting mechanism 4 and the hatch follow the movement to achieve quick opening, and the damping rod 12 and the driven rod 13 at both ends of the transmission shaft 11 rotate in a straight line and then achieve self-locking. The damping rod 12 itself has a damping and buffering function. After the hatch is opened at a large angle in an instant, damping and buffering are generated, and the hatch is firmly locked at the maximum opening angle due to the self-locking of the mechanism.

[0053] After the water throwing operation is completed, the transmission shaft 11 on the lifting mechanism 4 drives the damping rod 12 and the driven rod 13 to rotate and release the self-locking, and then continues to drive the water throwing door 3 to rotate and close around the suspension hinge 7. The push rod shaft 14 on the locking mechanism 5 is fixedly connected to the cam 15 to make a linear motion, driving the lock slot 17 to rotate and engage with the lock pin joint 9 to lock the door. The cam 15 itself has a self-locking function to prevent the lock slot 17 from rotating and causing accidental opening. A pre-position spring 16 is provided on the push rod shaft 14 to provide resistance after locking to prevent the locking mechanism 5 from being accidentally opened in the air due to inertial load.

[0054] After the flood hatch is locked, the locking mechanism 5 locks the hatch and squeezes the sealing belt 18 to achieve sealing. The hanging hinge 7, ear piece 10, lifting mechanism 4 and locking mechanism 5 on the flood hatch 3 are all distributed outside the sealing area of ​​the discharge port 6 hatch, avoiding the immersion of the hatch moving parts in the liquid fire extinguishing medium and minimizing the anti-corrosion pressure of the moving mechanism of the flood hatch.

[0055] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An external flooding hatch structure for an aircraft mechanism, characterized in that: The invention comprises a water-dropping hatch (3) and a door frame (2), wherein the water-dropping hatch (3) is mounted on the door frame (2), and the door frame (2) is used to fix the water-dropping hatch (3); a hanging hinge joint is arranged on one side of the water-dropping hatch (3), and a lifting structure (4) and a locking mechanism (5) are arranged on the other side; the other side of the water-dropping hatch (3) is engaged with a locking groove (17) on the locking mechanism (5) via a locking pin joint (9).

2. The aircraft mechanism external flooding hatch structure according to claim 1, characterized in that: Both ends of the water-dropping hatch (3) are connected to the lifting mechanism (4) via lugs (10).

3. The aircraft mechanism external flooding hatch structure according to claim 2, characterized in that: The lifting mechanism (4) comprises a transmission shaft (11), a damping rod (12) and a driven rod (13); the transmission shaft (11) is fixed on the door frame (2); one end of the damping rod (12) is fixedly connected to both ends of the transmission shaft (11); the other end is hinged to the driven rod (13); the driven rod (13) is connected to the flooding door (3) via an ear piece (10); and the lifting mechanism (4) has the functions of quick opening, buffering, self-locking and releasing self-locking.

4. The aircraft mechanism external flooding hatch structure according to claim 2, characterized in that: The door frame (2) is provided with mounting interfaces for a door lifting mechanism (4) and a locking mechanism (5).

5. The aircraft mechanism external flooding hatch structure according to any one of claims 1 to 4, characterized in that: The door locking mechanism (5) comprises a push rod shaft (14), a cam (15) and a pre-position spring (16); the push rod shaft (14) is fixed on the door frame (2); the cam (15) is fixedly connected to the push rod shaft (14); one end of the lock groove (17) is embedded in the cam (15) slide groove, and the other end is engaged with the lock pin joint (9) on the flooding door (3); the locking mechanism (5) has the function of preventing accidental opening.

6. The aircraft mechanism external flooding hatch structure according to any one of claims 1 to 4, characterized in that: The water-dropping hatch (3) is an inverted integral machined structural component, and a lock pin joint (9) is arranged on the door body structure (8) of the water-dropping hatch (3).

7. The aircraft mechanism external flooding hatch structure according to any one of claims 1 to 4, characterized in that: The water-dropping door (3), suspension hinge (7), lifting mechanism (4) and locking mechanism (5) are all arranged outside the door sealing area at the discharge port (6) and inside the fuselage fairing shape to prevent the movable parts of the water-dropping door (3) from being immersed in the liquid fire extinguishing medium.

8. An aircraft having an external flood hatch structure according to any one of claims 1 to 7, characterized in that: The invention comprises an aircraft body (1) and a discharge port (6) provided at the belly of the aircraft body (1); a door frame (2) is installed at the discharge port (6); four water-dropping hatches (3) are installed at the outside of the discharge port (6) through the door frame (2); and an annular sealing belt (18) is provided on the lower surface of the discharge port (6); one side of the water-dropping hatch (3) is hinged to the aircraft body (1) through a hanging hinge joint, and the water-dropping hatch (3) is buckled onto the sealing belt (18) of the discharge port (6).

9. The aircraft according to claim 8, characterized in that The sealing belt (18) is fixed to the lower surface of the discharge port (6) via a sealing belt pressing piece (19); the sealing belt (18) has a C-shaped cross section; the water-dropping hatch (3) is buckled onto the sealing belt (18); the lower surface of the sealing belt (18) is squeezed by the water-dropping hatch (3) and the upper surface is subjected to water pressure.

10. The aircraft according to claim 8, characterized in that A fuselage fairing (20) is arranged around the water-dropping hatch (3) to maintain the aerodynamic shape of the aircraft and seal the fire-extinguishing medium in the water tank when the water-dropping hatch (3) is closed.

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