Composite cabin door with combined sandwich structure

Abstract

The invention provides a composite cabin door with a combined sandwich structure. A sandwich layer in a special-shaped area of the cabin door is made of a foam sandwich material; the sandwich layer in the installation area of the accessories of the cabin door is made of filler, and the accessories need to be installed through screws and bolts; the sandwich layer in the load-bearing area of the cabin door is made of a high-density honeycomb material; a sandwich layer in a non-bearing area of the cabin door is made of a low-density honeycomb material; the density and strength of the low-density honeycomb material are smaller than those of the high-density honeycomb interlayer, so that the non-bearing area is designed to be light. The total weight of the cabin door can be reduced to the greatest extent under the condition that the equipment mounting requirement and the rigidity and strength requirements are met; meanwhile, metal parts exposed in the air are reduced, and the problems of corrosion and abrasion of cabin door parts are solved; and splicing areas of different sandwich layer materials are locally bonded and reinforced, so that the damage risk of the composite cabin door is reduced.

Description

Technical Field

[0001] The present invention belongs to the field of helicopter cargo door design, and particularly relates to a composite material door with a combined sandwich structure. Background Art

[0002] The doors of traditional helicopters mainly adopt a stiffened panel structure, and the parts of the door are assembled by means of riveting, bolt connection, etc. The traditional metal tail door is heavy, the production and assembly procedures are complex, the precision control is difficult, and the metal parts and standard parts often have rust problems. In view of this problem, a composite material tail door for helicopters has been invented.

[0003] It is difficult for metal materials to meet the requirements of helicopter weight reduction, and the proportion of composite materials on helicopters is increasing. By using composite materials to manufacture the door, the weight of the door can be reduced while meeting the requirements of stiffness and strength by adjusting the composition and arrangement between different materials.

[0004] When manufacturing the door with metal materials, a large number of molds need to be manufactured before the production of parts, and the workload of part assembly is large. Due to the accumulation of part tolerances and assembly tolerances, it is difficult to control the precision during the final assembly of the door. The composite material door is integrally formed in the production stage, reducing the number of molds and simplifying the production process, thus greatly improving the production efficiency.

[0005] The working environment of helicopters is complex and harsh, and metal materials often face problems of rust and wear. The composite material door can show stronger corrosion resistance and wear resistance in different environments.

[0006] However, the existing composite material doors have the problem of large mass. Summary of the Invention

[0007] The present invention provides a composite material door with a combined sandwich structure, which alleviates the problem of large mass existing in the existing composite material doors.

[0008] The present invention provides a composite material door with a combined sandwich structure. The sandwich layer in the special-shaped area of the door adopts a foam sandwich material;

[0009] The sandwich layer in the installation area of the accessories of the door adopts a filler, and the accessories need to be installed by screws and bolts;

[0010] The sandwich layer in the load-bearing area of the door adopts a high-density honeycomb material;

[0011] The sandwich layer in the non-load-bearing area of the door adopts a low-density honeycomb material;

[0012] The density and strength of the low-density honeycomb material are less than those of the high-density honeycomb sandwich, enabling lightweight design in the non-load-bearing area.

[0013] Optionally, at the junction of different sandwich layer materials, a splicing gap of 1-2 mm is provided between the two sandwich materials, and the splicing gap is filled with adhesive.

[0014] Optionally, the layup of the cabin door body from the film-applied surface to the non-film-applied surface is as follows:

[0015] Fiberglass cloth, carbon fiber cloth, sandwich layer, embedded metal parts, carbon fiber cloth, fiberglass cloth;

[0016] The number of carbon fiber cloth layers at the junction of different sandwich layer materials of the cabin door is at least two layers more than that in other areas, serving as a local strengthening layup;

[0017] The boundary of the layer close to the sandwich layer in the local strengthening layup is not less than 15 mm away from the junction, and the size of the local strengthening layup gradually increases from the inside to the outside, and the boundary spacing between adjacent layers is not less than 15 mm.

[0018] Optionally, the load-bearing area of the cabin door is used for carrying goods and personnel;

[0019] The load-bearing area of the cabin door is located below the equipment to be maintained and repaired in the engine room.

[0020] Optionally, the accessories of the cabin door include: hinges, handles, cabin door locks.

[0021] Optionally, the density of the high-density honeycomb material is not less than 48 kg / m 3 , the in-plane shear strength is not less than 0.9 MPa, and the in-plane compression strength is not less than 1.3 MPa;

[0022] The density of the low-density honeycomb material is not less than 29 kg / m 3 , the in-plane shear strength is not less than 0.37 MPa, and the in-plane compression strength is not less than 0.33 MPa.

[0023] Optionally, the load-bearing area of the cabin door is located at the center of the cabin door, and the non-load-bearing area of the cabin door is located on both sides of the cabin door.

[0024] Optionally, the surface of the load-bearing area of the cabin door is sprayed with an anti-slip and wear-resistant coating.

[0025] Optionally, the installation area of the accessories of the cabin door is a plane;

[0026] Through-hole inserts and blind-hole inserts are provided in the sandwich layer within the installation area of the accessories of the cabin door;

[0027] The through-hole inserts and blind-hole inserts are respectively used to connect large-load accessories and small-load accessories.

[0028] Optionally, the special-shaped area of the cabin door includes the peripheral sealing area of the cabin door.

[0029] The present invention provides a composite cabin door with a combined sandwich structure, which can minimize the total weight of the cabin door while meeting the requirements for equipment installation, stiffness, and strength. At the same time, it reduces the metal parts exposed to the air, improves the problems of rust and wear of the cabin door parts, and locally bonds and strengthens the splicing areas of different sandwich layer materials to reduce the damage risk of the composite cabin door. In the present invention, the configuration of the composite cabin door gives full play to the design advantages of composite materials and reduces the weight of the cabin door while meeting the requirements for stiffness and strength. The present invention adopts an integral molding process. Compared with traditional cabin doors, it reduces the number of parts in the cabin door assembly, reduces a large number of mechanical connections, reduces the number of processing molds, simplifies the production process, reduces the assembly workload, and improves production efficiency. The present invention reduces the number of metal parts exposed to the air and improves the problems of rust and wear of the cabin door parts. The present invention locally strengthens the splicing areas of different sandwich layers of the composite cabin door to reduce the damage risk of the composite cabin door. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a design of a tail cabin door assembly provided by the present invention;

[0031] Figure 2 It is a design of a composite cabin door with a combined sandwich structure provided by the present invention;

[0032] Figure 3 It is a sectional view A-A of the composite cabin door with a combined sandwich structure provided by the present invention;

[0033] Figure 4 It is a schematic diagram of the filler sandwich area 130 of the composite cabin door with a combined sandwich structure provided by the present invention Figure 1 ;

[0034] Figure 5 Schematic diagram of the filler sandwich area 130 of the composite cabin door with a combined sandwich structure provided by the present invention Figure 2 ;

[0035] Figure 6 Design of the splicing area of different sandwich layer materials of the composite cabin door with a combined sandwich structure provided by the present invention;

[0036] DESCRIPTION OF REFERENCE NUMERALS:

[0037] 100 Composite cabin door with a combined sandwich structure;

[0038] 200 Door installation accessories;

[0039] 110 Low-density honeycomb sandwich area;

[0040] 120 High-density honeycomb sandwich area;

[0041] 130 Filler sandwich area;

[0042] 140 Foam sandwich area;

[0043] 131 Filler block;

[0044] 132-1 Through-hole insert;

[0045] 133 Embedded metal plate;

[0046] 132-2 Blind-hole insert;

[0047] 101 General ply;

[0048] 102 Local strengthening ply;

[0049] 103 Adhesive;

[0050] 111 Low-density honeycomb;

[0051] 121 High-density honeycomb. Detailed implementation manners

[0052] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0053] The features and illustrative embodiments of various aspects of the present invention will be described in detail below. In the following detailed description, many specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those of ordinary skill in the art that the present invention may be practiced without some of these specific details. The following description of the embodiments is only intended to provide a better understanding of the present invention by showing examples of the present invention. The present invention is in no way limited to any specific settings and methods set forth below, but covers any improvements, substitutions and modifications of structures, methods, and devices without departing from the spirit of the present invention. Well-known structures and technologies are not shown in the drawings and the following description to avoid unnecessarily obscuring the present invention.

[0054] It should be noted that, without conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other, and the various embodiments may be referenced and cited with each other. The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0055] The present invention will be further described in detail below in conjunction with the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0056] AsFigures 1-6 As shown, the present invention provides a composite cabin door with a combined sandwich structure, and the door body of the cabin door is produced from integrally formed composite materials. Since different parts are installed in different areas of the cabin door, different tasks are undertaken, and different loads are borne, the flexible design advantages of composite materials are fully utilized to carry out the material and ply design of the composite cabin door, and different ply laying methods and sandwich layer materials are selected for different areas of the cabin door.

[0057] This composite cabin door with a combined sandwich structure can, while meeting the requirements for equipment installation and stiffness and strength, minimize the total weight of the cabin door to the greatest extent; at the same time, reduce the metal parts exposed to the air and improve the problems of rust and wear of the cabin door parts; perform local bonding and strengthening on the splicing areas of different sandwich layer materials to reduce the risk of damage to the composite cabin door.

[0058] Exemplarily, for the composite cabin door with a combined sandwich structure provided by the present invention, due to the different functions of different areas of the cabin door, the material and ply design of the composite cabin door is carried out specifically. Different ply laying methods are designed for different areas of the cabin door, different sandwich layer materials are selected, and they are integrally formed into a composite cabin door. This composite cabin door is produced from unidirectional or bidirectional reinforced fiber plies, a resin matrix, various sandwich materials, and auxiliary materials such as adhesives.

[0059] Exemplarily, for the door body 100 of the composite cabin door with a sandwich structure, the plies are in sequence a fiberglass cloth (film side), 2 - 4 layers of carbon fiber cloth, a sandwich layer, an embedded metal part, 2 - 4 layers of carbon fiber cloth, and a fiberglass cloth (non - film side).

[0060] Exemplarily, the fiberglass cloth of the door body 100 of the composite cabin door with a sandwich structure mainly plays the following roles:

[0061] Prevent galvanic corrosion caused by the potential difference between the carbon fiber cloth of the cabin door and the surrounding metal structures;

[0062] The fiberglass cloth (film side) is used to form the outer surface of the helicopter cabin door with good surface quality, good contour, and resistance to foreign object damage;

[0063] The fiberglass cloth (non - film side) is used to form the inner surface of the helicopter cabin door that can be stepped on and is wear - resistant.

[0064] Exemplarily, the carbon fiber cloth of the door body 100 of the composite cabin door with a sandwich structure mainly plays the following roles:

[0065] Improve the overall stiffness and strength of the cabin door, and improve the load - bearing capacity and anti - deformation ability of the cabin door;

[0066] Increase the number of layers of carbon fiber cloth in local areas of the cabin door to play a role in local strengthening.

[0067] Exemplarily, the number of layers of carbon fiber cloth is increased in the local area. The local strengthening ply 102 is not less than 2 layers. The distance between the boundary of the innermost local strengthening ply 102 and the core splicing seam is not less than 15 mm. The local strengthening ply 102 gradually becomes larger from the inside to the outside, and the boundary distance between adjacent layers is not less than 15 mm.

[0068] Exemplarily, the core layer of the composite cabin door body 100 of the sandwich structure is divided into a low-density honeycomb sandwich area 110, a high-density honeycomb sandwich area 120, a filler sandwich area 130, and a foam sandwich area 140 according to different core layer materials.

[0069] Exemplarily, at the junction of different core layer materials, a splicing gap of 1-2 mm is left between the two core materials, and then the splicing gap is bonded with an adhesive.

[0070] Exemplarily, the low-density honeycomb sandwich area 110 serves as a personnel passage. There is no long-term personnel operation requirement in this area. Therefore, a weight reduction design is carried out for this area, and the sandwich material is selected as low-density honeycomb with lower strength but smaller density.

[0071] Exemplarily, the high-density honeycomb sandwich area 120 serves as a personnel operation area. There is a need for personnel to step on and operate for a long time in this area. Therefore, the sandwich material in this area is selected as high-density honeycomb with a larger density but higher strength, and an anti-slip and wear-resistant coating is sprayed on the surface of this area to meet the needs of personnel walking, operating, and placing heavy objects in this area.

[0072] Exemplarily, the filler sandwich area 130 and the foam sandwich area 140 serve to install door accessories of the cabin door. Door accessories can be installed on the door body in this area by means of screws, bolts, or adhesives, etc.

[0073] Exemplarily, in the filler sandwich area 130, the filler has a strong adhesion to the ply and is not easily debonded, but the filler has a heavy density. When meeting the connection requirements of small areas and large loads, the filler is selected as the sandwich material, mainly including the following connections: large-load through-hole connections and small-load non-through-hole connections.

[0074] Exemplarily, the inner surface of the cabin door in the filler sandwich area 130 can be made into a flat surface, which can avoid the problem that it is difficult to assemble door accessories due to the curvature of the cabin door body, and is convenient for installing door accessories with the same flat contact surface.

[0075] Exemplarily, for large-load through-hole connection, during the production stage of the composite material hatch door, the through-hole insert 132-1 and the metal plate 133 are pre-buried. The through-hole insert 132-1 is located within the filler block 131, and the metal plate 133 is located between the filler block 131 and the ply. This method is applicable to the case where the load of the installed parts is large, and bolts and nuts can be used to install the hatch door accessories on the composite material hatch door 100.

[0076] Exemplarily, for small-load non-through-hole connection, during the production stage of the composite material hatch door, the blind-hole insert 132-2 is pre-buried, and the through-hole insert 132-1 is located within the filler block 131. This method is applicable to the case where the load of the installed parts is small, and bolts or screws can be used to install the hatch door accessories on the composite material hatch door 100.

[0077] Exemplarily, for the foam sandwich area 140, the foam has strong plasticity, can be processed into complex cross-sections, and has a low density. Therefore, the sandwich material in this area is selected as foam, which provides a sealing surface for the hatch door, and the sealing strip is installed on the composite material hatch door 100 in a direct manner.

[0078] As Figure 1 shown, the present invention provides a design of a tail hatch door assembly, mainly including a composite material hatch door 100 with a combined sandwich structure and hatch door installation accessories 200.

[0079] As Figure 2 shown, for a design of a composite material hatch door with a combined sandwich structure, the hatch door is divided into regions according to different core layer materials, mainly including a low-density honeycomb sandwich area 110, a high-density honeycomb sandwich area 120, a filler sandwich area 130, and a foam sandwich area 140.

[0080] As Figure 3 shown, the sectional view A-A of the composite sandwich material hatch door is provided as a supplementary illustration of Figure 2 ;

[0081] As Figure 4 and Figure 5 shown, according to the load conditions of the parts installed in this area, there are two configurations:

[0082] a) When the load is large, the filler sandwich area 130 includes a filler block 131, a through-hole insert 132-1, and an embedded metal plate 133;

[0083] b) When the load is small, the filler sandwich area 130 includes a filler block 131 and a blind-hole insert 132-2;

[0084] As Figure 6The design of the splicing area of different sandwich layer materials of the shown composite sandwich hatch. The figure shows a cross-sectional view of the composite material layup at the junction of the low-density honeycomb sandwich area 110 and the high-density honeycomb sandwich area 120, mainly including the low-density honeycomb 111, the high-density honeycomb 121, the general layup 101, the local strengthening layup 102 and the adhesive 103. The composite material design at the junctions of the sandwich layers in other positions is similar.

[0085] As mentioned above, it is only a further embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the scope disclosed by the present invention, according to the technical solution and concept of the present invention, makes equivalent substitutions or changes, all belong to the protection scope of the present invention.

Claims

1. A composite material cabin door with a combined sandwich structure, characterized in that, The sandwich layer within the special-shaped area of the hatch door uses foam sandwich material; The sandwich layer within the installation area of the hatch door accessories uses filler, and the accessories need to be installed through screws and bolts; The sandwich layer within the load-bearing area of the hatch door uses high-density honeycomb material; The sandwich layer within the non-load-bearing area of the hatch door uses low-density honeycomb material; The density and strength of the low-density honeycomb material are less than those of the high-density honeycomb sandwich, enabling lightweight design for the non-load-bearing area.

2. The composite material cabin door with a combined sandwich structure according to claim 1, characterized in that, At the junction of different sandwich layer materials, a splicing gap of 1 - 2 mm is provided between the two sandwich materials, and the splicing gap is filled with adhesive.

3. The composite material cabin door with a combined sandwich structure according to claim 2, characterized in that, The layering of the hatch door body from the film-applied surface to the non-film-applied surface is as follows: Fiberglass cloth, carbon fiber cloth, sandwich layer, embedded metal parts, carbon fiber cloth, fiberglass cloth; The number of carbon fiber cloth layers at the junction of different sandwich layer materials of the hatch door is at least two layers more than that in other areas, serving as a local strengthening layering; The boundary of the layer closest to the sandwich layer in the local strengthening layering is not less than 15 mm from the junction. The size of the local strengthening layering gradually increases from the inside to the outside, and the boundary spacing between adjacent layers is not less than 15 mm.

4. The composite material hatch with a combined sandwich structure according to claim 1, characterized in that The load-bearing area of the hatch door is used for carrying goods and personnel; The load-bearing area of the hatch door is located below the equipment to be maintained and repaired within the engine room.

5. The composite material cabin door with a combined sandwich structure according to claim 1, characterized in that, The accessories of the hatch door include: hinges, handles, and hatch door locks.

6. The composite material cabin door with a combined sandwich structure according to claim 1, characterized in that, The density of the high-density honeycomb material is not less than 48 kg / m 3 , the in-plane shear strength is not less than 0.9 MPa, and the in-plane compressive strength is not less than 1.3 MPa; The density of the low-density honeycomb material is not less than 29 kg / m 3 , the in-plane shear strength is not less than 0.37 MPa, and the in-plane compressive strength is not less than 0.33 MPa.

7. The composite material hatch with a combined sandwich structure according to claim 1, characterized in that, The load-bearing area of the hatch door is located at the center of the hatch door, and the non-load-bearing area of the hatch door is located on both sides of the hatch door.

8. The composite material hatch with a combined sandwich structure according to claim 1, characterized in that, The surface of the load-bearing area of the hatch door is sprayed with an anti-slip and wear-resistant coating.

9. The composite material cabin door with a combined sandwich structure according to claim 1, characterized in that, The installation area of the hatch door accessories is a flat surface; Through-hole inserts and blind-hole inserts are provided within the sandwich layer in the installation area of the hatch door accessories; The through-hole inserts and blind-hole inserts are respectively used to connect large-load accessories and small-load accessories.

10. The composite material cabin door with a combined sandwich structure according to claim 1, characterized in that, The special-shaped area of the hatch door includes the sealing area around the hatch door.

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