Aircraft thermal protection bay segment connection structure and method of assembly

Abstract

The application provides a connecting structure of a thermal protection cabin section of an aircraft and an assembling method thereof, the connecting structure comprising a cabin section shell and an assembled shell, a heatproof coating is sprayed on an outer layer of the cabin section shell, and a heat insulation material is arranged on an inner layer of the cabin section shell, a countersunk screw is inserted into the independent assembling body, and a thermal protection ring, an adapter ring and a thermal protection gasket are sequentially sleeved on an inner edge of a part of the cabin section shell from outside to inside; the adapter ring is provided with two rows of holes, wherein the first row of holes fixes and connects the cabin section shell and the adapter ring through the countersunk screw, and the second row of holes fixes and connects the adapter ring and the assembled shell through an adapter screw. The application has the advantages of simple structure, clear load transmission path, capability of guaranteeing that the cabin section structure meets the use requirements under force and thermal load, capability of meeting the working temperature environment of the assembled parts in the cabin, and capability of meeting the thermal protection requirements of the cabin section.

Description

Technical Field

[0001] This invention relates to the field of aircraft connectors, specifically to a connection structure for an aircraft thermal protection compartment and its assembly method. Background Technology

[0002] When an aircraft flies at supersonic speeds, complex gas-solid-thermal coupling phenomena occur due to shock wave compression, viscous friction, and other effects. This causes the air temperature near the wall to rise, and some of the heat energy is transferred to the low-temperature wall, resulting in severe aerodynamic heating of the cabin section. Since the cabin section has not reached thermal equilibrium, the heat continues to be transferred into the cabin through conduction, convection, and radiation, which will affect the operating temperature of the instruments and components inside the cabin. In order to ensure that the cabin section structure meets the requirements of high rigidity design and that the components inside the cabin work normally within the allowable temperature range, effective thermal protection design must be implemented.

[0003] Existing thermal protection methods mainly include radiation-based, ablation-based, heat sink-based, insulation-based, sweating-based, and heat pipe-based thermal protection. Except for the nose cone and wing leading edges, aircraft typically use high-temperature resistant materials such as ceramics, C / C, and C / SiC. The load-bearing structural materials for the cabin sections are mainly aluminum alloys, titanium alloys, and nickel / cobalt-based alloys. The operating temperature of aluminum alloys generally does not exceed 176℃, titanium alloys generally does not exceed 540℃, and nickel / cobalt materials generally do not exceed 1100℃. However, given that a certain aircraft, under typical ballistic conditions, experiences a short-duration, high-heat-flux, and medium-enthalpy aerodynamic thermal environment, and requires minimal impact of aerodynamic heating on aerodynamic shape, lightweight cabin and thermal protection structures, and sufficient installation space for internal components, using traditional thermal protection methods would increase structural weight, affect flight performance indicators, and increase structural complexity. Summary of the Invention

[0004] To address the problems of existing technologies, this invention provides a connection structure for a thermal protection compartment of an aircraft and its assembly method. The structure is simple, the load transfer path is clear, and it can ensure that the compartment structure meets the usage requirements under force and thermal loads, while also meeting the working temperature environment of the components inside the compartment and satisfying the thermal protection requirements of the compartment.

[0005] This invention provides a connection structure for a thermal protection section of an aircraft, including a section shell and a component shell. The outer layer of the section shell is coated with a heat-resistant coating, and the inner layer is provided with heat-insulating material. The heat-resistant coating, the section shell, and the heat-insulating material form an independent assembly. A countersunk screw is inserted into the independent assembly. On the inner edge of the portion of the countersunk screw inserted into the section shell, a thermal protection ring, a transition ring, and a thermal protection gasket are sequentially fitted from the outside to the inside. The section shell has a reinforcing connecting boss at the location of the countersunk screw. The connecting boss is a raised structure relative to the inner surface of the section shell. The thermal protection ring has a groove structure that mates with the connecting boss of the section shell. The transition ring has two rows of holes. The first row of holes is used to fix the section shell and the transition ring together with countersunk screws, and the second row of holes is used to fix the transition ring and the component shell together with transition screws.

[0006] In a further improvement, the first row of holes of the adapter ring are adapter ring through holes, and a heat protection bushing is installed in the adapter ring through holes. The outer surface of the heat protection bushing is in contact with the inner surface of the heat protection ring, and the inner surface of the heat protection bushing is in contact with the heat protection gasket.

[0007] In a further improvement, the two rows of holes on the adapter ring are arranged in a cross pattern.

[0008] In a further improvement, the adapter ring is separated from the compartment shell by a thermal protection ring at the connection point, and there are gaps between the adapter ring and the compartment shell at other locations.

[0009] In a further improvement, the adapter ring has an adapter ring boss with a through hole, and the component housing has a component housing boss with a threaded hole. The adapter screw connects the adapter ring and the component housing through the through hole and the threaded hole to form an integral structure.

[0010] In a further improvement, the countersunk screw connects and fixes the compartment shell, thermal protection ring, thermal protection bushing, adapter ring, and thermal protection gasket through a connecting nut.

[0011] In a further improvement, the thermal protection material has pre-drilled holes for countersunk screws. After the countersunk screws are installed, the holes are filled with silicone rubber.

[0012] The present invention also provides an assembly method for a connection structure of a thermal protection compartment of an aircraft, comprising the following steps: 1) The cabin shell, outer protective coating, and inner thermal insulation material are assembled into an independent integral structure; the outer protective coating is fixed to the outer surface of the cabin shell by spraying, and the inner thermal insulation material is bonded to the inner wall of the cabin shell by high-temperature adhesive; the inner thermal insulation material is selected as a lightweight thermal protection material with low thermal conductivity, including epoxy thermal protection material and aerogel. 2) Assemble the adapter ring and the housing into an independent integral structure using screws. When assembling the adapter ring and the housing, apply medium-strength removable thread fastener when installing the screws. 3) Assemble the two assemblies together: the overall structure of the compartment shell and the overall structure of the component shell. During assembly, install the thermal protection bushing in the hole of the adapter ring, then install the thermal protection gasket, and connect and fix the two assemblies with countersunk screws and nuts. During installation, the nuts are designed with a groove structure. Tighten the countersunk screws on the outside of the compartment shell by fixing the groove of the nut. Apply thread-locking agent to loosen the screw and nut connection. 4) After assembly, apply high-temperature resistant silicone rubber to the pre-drilled holes at the countersunk screw positions on the compartment shell, and fill and shape them. The beneficial effects of this invention are as follows: 1. The structure is simple and the load transfer path is clear, which can ensure that the compartment structure meets the usage requirements under force and heat loads, and at the same time meet the working temperature environment of the components inside the compartment and the thermal protection requirements of the compartment.

[0013] 2. The adapter ring is connected to the housing by countersunk screws. The threaded hole on the housing is a blind hole to prevent foreign objects from entering the housing during assembly and to provide a seal for the housing.

[0014] 3. The adapter ring and the component housing adopt a boss structure to avoid excessive contact area between the component housing and the adapter ring, which would transfer too much heat load to the component housing.

[0015] 4. To improve connection rigidity, the designed boss is located at the angle between the side wall and the inner wall of the shell. The adapter ring and the complete shell are assembled to form an independent assembly structure, which avoids damage to the threaded holes of the complete shell caused by repeated disassembly and assembly on the compartment shell. The adapter ring and the complete shell are connected by screws, and thread fastener is used to prevent loosening during connection.

[0016] 5. To improve the connection rigidity of the adapter ring, the two rows of holes on the adapter ring are arranged in a cross pattern. The adapter ring does not directly contact the compartment shell. There is a thermal protection ring in the middle of the adapter ring where it connects with the component shell. In other positions, there is a gap between the outer surface of the adapter ring and the inner surface of the thermal insulation material to prevent the thermal load from being directly transferred from the compartment shell to the adapter ring.

[0017] 6. The thermal protection ring is made of a rigid protective material with low thermal conductivity. The thermal protection ring has a groove structure and a through hole structure. The groove structure matches the boss of the compartment shell, and the through hole is used for countersunk screws to pass through. The countersunk screws and nuts are used to connect and fix the compartment shell, thermal protection ring, adapter ring, thermal protection bushing, and thermal protection gasket. The thermal protection gasket and thermal protection bushing are made of rigid low thermal conductivity material. The thermal protection bushing is installed in the through hole of the adapter ring to prevent the countersunk screw from directly transferring the heat load to the adapter ring, thereby reducing the heat load transferred to the component shell.

[0018] 7. In addition to the heat protection ring connection area on the inner wall of the compartment shell, thermal insulation material is added to other areas. The thermal insulation material can be epoxy or aerogel thermal protection material, which has the characteristics of low density and low thermal conductivity, meeting the requirements of lightweighting, while reducing the heat transferred from the compartment shell and lowering the ambient temperature inside the compartment.

[0019] 8. The heat transfer to the component shell by heat conduction is effectively reduced through the thermal protection compartment connection structure, while the thermal load on the component shell by radiation and convection is also reduced. The thermal insulation material and connection structure ensure that the compartment structure meets the usage requirements under force and thermal loads, while also ensuring the working environment of the components inside the compartment. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the connection structure of the thermal protection section; Figure 2 Left view of the hull section; Figure 3 This is a schematic diagram of the hull section. Figure 4 Left view of the thermal protection ring; Figure 5 This is the front view of the thermal protection ring; Figure 6 This is a schematic diagram of the adapter ring and the housing assembly. Figure 7 for Figure 6 Sectional view of AA; Figure 8 Main view of the connecting nut; Figure 9 A bottom view of the connecting nut; Figure 10 This is a schematic diagram of a double-row hole adapter ring.

[0022] In the diagram, 1 represents the heat-resistant coating, 2 represents the compartment shell, 3 represents the heat insulation material, 4 represents the heat protection ring, 5 represents the adapter ring, 6 represents the connecting nut, 7 represents the countersunk screw, 8 represents the heat protection bushing, 9 represents the heat protection gasket, 10 represents the complete shell, 11 represents the connecting boss, 12 represents the groove structure, 13 represents the through hole of the heat protection ring, 14 represents the adapter ring boss, 15 represents the complete shell boss, 16 represents the adapter ring through hole, and 17 represents the adapter screw. Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] This invention provides a connection structure for thermal protection compartments, such as... Figure 1-10As shown, the assembly comprises a heat-resistant coating 1, a compartment shell 2, heat insulation material 3, a heat protection ring 4, an adapter ring 5, a connecting nut 6, a countersunk screw 7, a heat protection bushing 8, a heat protection gasket 9, a complete housing 10, and an adapter screw 17. The heat-resistant coating 1 is sprayed onto the compartment shell 2. The heat-resistant coating 1 has pre-drilled holes for installing the countersunk screw 7. The heat insulation material 3 and the heat protection ring 4 are fixed to the inner surface of the compartment shell 2. The heat-resistant coating 1, compartment shell 2, heat protection ring 4, and heat insulation material 3 are combined into an independent assembly. The compartment shell 2 has a reinforcing connecting boss 11 at the countersunk screw 7 location. The connecting boss 11 is a raised structure relative to the inner surface of the compartment shell 2. The heat protection ring 4 is a low thermal conductivity hard protective material. The heat protection ring 4 features a groove structure 12 and a heat protection ring through hole 13. The groove structure 12 mates with the connecting boss 11 of the compartment shell 2. A thermal protection bushing 8 is installed within the transition ring through-hole 16 of the transition ring 5. The outer surface of the thermal protection bushing 8 contacts the inner surface of the thermal protection ring 4, and the inner surface of the thermal protection bushing 8 contacts the thermal protection gasket 9. The transition ring 5 has two rows of holes. The first row of holes is used to install the thermal protection bushing 8, and the countersunk screw 7 passes through these holes to fix the compartment shell 2 and the transition ring 5. The second row of holes is used for the transition screw 17 to pass through, fixing the transition ring 5 and the component shell 10. To improve the connection rigidity of the transition ring, the two rows of holes are arranged alternately. The transition ring 5 does not directly contact the compartment shell 2. A thermal protection ring 4 is located in the middle of the connection position between the transition ring 5 and the compartment shell 2. At other positions, there is a gap between the transition ring 5 and the compartment shell 2 to avoid direct heat conduction. The adapter ring 5 has an adapter ring boss 14 with a through hole. The housing 10 has a housing boss 15. The adapter screw 17 passes through the through hole on the adapter ring boss 14 of the adapter ring 5 and is installed in the threaded hole on the housing boss 15. The threaded hole on the housing boss 15 is a blind hole, connecting the adapter ring 5 and the housing 10 to form an integral structure. The housing 10 is fixed to the adapter ring 5. The countersunk screw 7 passes through the screw through hole of the compartment housing 2, the heat protection ring through hole 13 of the heat protection ring 4, the heat protection bushing 8, and the heat protection gasket 9. The compartment housing 2, the heat protection ring 4, the heat protection bushing 8, the adapter ring 5, and the heat protection gasket 9 are connected and fixed by the connecting nut 6. The heat protection material 1 has reserved countersunk screw mounting holes. After the countersunk screw 7 is installed, the mounting holes are filled with silicone rubber. After all components are assembled, a compartment connection structure with heat protection function is formed.

[0025] The specific method of using this invention is as follows: During supersonic flight, the aerodynamic heat load is first transferred to the cabin shell via the heat-resistant coating. The heat load is primarily transferred to the main shell via two heat transfer paths: conduction and radiation / convection. During conduction, the main shell and cabin shell do not directly contact each other; a low thermal conductivity insulation device separates them. The external heat-resistant coating and insulation material effectively reduce the internal temperature of the cabin shell, thus reducing the heat load transferred to the main shell via conduction. During radiation and convection, gaps exist at all locations except for the connection point where the outer surface of the main shell contacts the transition ring boss. The external heat-resistant coating and insulation material lower the inner surface temperature of the insulation material, effectively reducing the heat transferred to the main shell via radiation and convection.

[0026] During the assembly of the thermal protection section connection structure, the section shell, outer protective coating, inner thermal insulation material, and thermal protection ring are first assembled into an independent integral structure. The outer protective coating is fixed to the outer surface of the section shell by spraying to ensure the aircraft's shape. The inner thermal insulation material can be selected from lightweight, low thermal conductivity thermal protection materials such as epoxy thermal protection materials and aerogel, and can be bonded to the inner wall of the section shell with high-temperature adhesive. The inner thermal insulation material and the thermal protection ring are installed simultaneously. Next, the adapter ring and the component shell are assembled into an independent integral structure using screws. When assembling the adapter ring and the component shell, the screws are removable with medium strength coating. After the thread-locking agent, the adapter ring and the complete housing are installed, they do not need to be disassembled again. Then, the two assemblies, the overall structure of the compartment housing and the overall structure of the complete housing, are assembled together. During assembly, the thermal protection bushing is installed in the hole of the adapter ring, and then the thermal protection gasket is installed. The two assemblies are connected and fixed by countersunk screws and nuts. During installation, the nut is designed with a groove structure. By fixing the groove of the nut, the countersunk screw is tightened on the outside of the compartment housing. When connecting the screw and nut, thread-locking agent can be applied to loosen it. Finally, after the assembly is completed, high-temperature resistant silicone rubber is applied to the reserved holes at the countersunk screw positions on the compartment housing to fill and shape them.

[0027] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. In particular, for the device embodiments, the above descriptions are merely preferred embodiments of the present invention. Since they are fundamentally similar to the method embodiments, the descriptions are relatively simple, and relevant parts can be referred to the descriptions of the method embodiments. The above descriptions are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention, without departing from the principle of the present invention, should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A thermal protection section connection structure for an aircraft, comprising a section shell and a prefabricated shell, wherein the outer layer of the section shell is coated with a heat-resistant coating and the inner layer is provided with heat-insulating material, and the heat-resistant coating, the section shell, and the heat-insulating material form an independent assembly, characterized in that: The independent assembly contains countersunk screws. On the inner edge of the portion of the countersunk screw inserted into the compartment shell, a thermal protection ring, a transition ring, and a thermal protection gasket are sequentially fitted from the outside in. The compartment shell has a reinforcing connecting boss at the countersunk screw location. The connecting boss is a raised structure relative to the inner surface of the compartment shell. The thermal protection ring has a groove structure that mates with the connecting boss of the compartment shell. The transition ring has two rows of holes. The first row of holes secures the compartment shell and the transition ring together using countersunk screws, while the second row of holes secures the transition ring and the assembly shell together using transition screws.

2. The aircraft thermal protection compartment connection structure according to claim 1, characterized in that: The first row of holes of the adapter ring are adapter ring through holes, and a heat protection bushing is installed in the adapter ring through holes. The outer surface of the heat protection bushing is in contact with the inner surface of the heat protection ring, and the inner surface of the heat protection bushing is in contact with the heat protection gasket.

3. The aircraft thermal protection compartment connection structure according to claim 1 or 2, characterized in that: The two rows of holes on the adapter ring are arranged in a cross pattern.

4. The aircraft thermal protection compartment connection structure according to claim 1, characterized in that: The adapter ring is separated from the compartment shell by a thermal protection ring at the connection point, and there are gaps between the adapter ring and the compartment shell at other locations.

5. The aircraft thermal protection compartment connection structure according to claim 1, characterized in that: The adapter ring has an adapter ring boss with a through hole, and the housing has a housing boss with a threaded hole. The adapter screw connects the adapter ring and the housing through the through hole and the threaded hole to form an integral structure.

6. The aircraft thermal protection compartment connection structure according to claim 1, characterized in that: The countersunk screws connect and fix the compartment shell, thermal protection ring, thermal protection bushing, adapter ring, and thermal protection gasket through the connecting nuts.

7. The aircraft thermal protection compartment connection structure according to claim 1, characterized in that: The thermal protection material has pre-drilled holes for countersunk screws. After the countersunk screws are installed, the holes are filled with silicone rubber.

8. An assembly method for a connection structure of a thermal protection compartment of an aircraft, characterized in that... Includes the following steps: 1) The hull section, outer protective coating, and inner thermal insulation material are assembled into an independent integral structure; 2) Assemble the adapter ring and the housing into an independent integral structure using screws. When assembling the adapter ring and the housing, apply medium-strength removable thread fastener when installing the screws. 3) Assemble the two assemblies together: the overall structure of the compartment shell and the overall structure of the component shell. During assembly, install the thermal protection bushing in the hole of the adapter ring, then install the thermal protection gasket, and connect and fix the two assemblies with countersunk screws and nuts. During installation, the nuts are designed with a groove structure. Tighten the countersunk screws on the outside of the compartment shell by fixing the groove of the nut. Apply thread-locking agent to loosen the screw and nut connection. 4) After assembly, apply high-temperature resistant silicone rubber to the pre-drilled holes at the countersunk screw positions on the compartment shell, and fill and shape them.

9. The assembly method of the aircraft thermal protection section connection structure according to claim 8, characterized in that: In step 1), the outer protective coating is fixed to the outer surface of the compartment shell by spraying, and the inner thermal insulation material is bonded to the inner wall of the compartment shell by high-temperature adhesive.

10. The assembly method of the aircraft thermal protection section connection structure according to claim 8 or 9, characterized in that: The internal insulation material is selected from lightweight, low thermal conductivity heat protection materials, including epoxy heat protection materials and aerogel.

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