Detachable Structure Fuel Tank at the Leading Edge of a UAV Wing and Forming Method

Abstract

The present invention relates to the technical field of unmanned aerial vehicles, and specifically discloses a detachable structure fuel tank at the leading edge of an unmanned aerial vehicle wing and a forming method. The fuel tank includes a connection assembly, a fuel tank body, and a fuel system assembly installed on the fuel tank body; the outer side surface of the fuel tank body is coplanar with the aerodynamic contour surface of the leading edge of the wing, forming a lift characteristic surface at the leading edge of the unmanned aerial vehicle wing. The forming method specifically includes: laying and curing each component; drilling holes in each component; clamping and positioning the fuel tank skin; clamping and positioning the skeleton assembly in the fuel tank body; bonding and curing the fuel tank skin and the skeleton assembly at room temperature and non-destructive testing; construction of external sealing at the seams of the fuel tank body; installing the fuel system assembly and the sealing cover. The present invention has good interchangeability and maintainability; the leading edge fuel tank bears small load, has small deformation, and has a small risk of oil leakage; and the gravity of the fuel can offset the aerodynamic load deformation of the leading edge skin, ensuring the aerodynamic lift effect of the unmanned aerial vehicle wing and improving the aerodynamic force.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicles, and more specifically, to a detachable structure fuel tank for the leading edge of an unmanned aerial vehicle wing and a forming method thereof. Background Art

[0002] Currently, in the prior art, the structural fuel tanks of most aircraft are arranged in the wing box area of the wing, which is the main load-bearing structure of the wing. It is impossible to realize the function requirements of convenient disassembly of the whole fuel tank and low-cost replacement and maintenance. Moreover, the structure in the wing box area bears a large load. After being loaded, the structure of the fuel tank area and the mechanical connection or bonded connection between various components deform greatly. Therefore, the risk of oil leakage from the fuel tank is relatively high. For the flexible fuel tank made of thin-walled rubber material, which is a non-load-bearing structure and can be replaced, the service life of such a fuel tank is short, and more installation structures need to be designed in the internal space of the airframe to fix the flexible fuel tank, resulting in a complex structure and a large increase in weight. At the same time, it is difficult to arrange in the area with a complex internal structure of the wing, and the risk of oil leakage during use is high.

[0003] At the same time, in the prior art, the leading edge skin of the lightweight designed unmanned aerial vehicle wing is thin, and the number of wing ribs is set small. Under the action of flight aerodynamic loads, the leading edge skin is prone to deformation, so that the conformity between the leading edge shape of the wing and the designed leading edge theoretical aerodynamic shape is poor, which cannot effectively guarantee the aerodynamic lift effect of the unmanned aerial vehicle wing and reduces the aerodynamic efficiency of the wing. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a detachable structure fuel tank for the leading edge of an unmanned aerial vehicle wing and a forming method thereof. First of all, the detachable structure fuel tank for the leading edge of the wing of the present invention has a simple structure, good formability and strong practicability, and can effectively increase the fuel loading capacity of the unmanned aerial vehicle, and can meet the different requirements for fuel loading capacity of different mission configurations of large unmanned aerial vehicles. Secondly, the structural fuel tank is connected to the main wing structure through a number of panel nuts and bolts, and can be detached from the wing as a whole, with good interchangeability and maintainability. Moreover, the fuel tank is arranged at the leading edge position of the wing, the connection load between the leading edge and the wing is small, the load borne by the fuel tank structure accounts for a small proportion, the fuel tank deformation is small, and the risk of oil leakage is small. Finally, the gravity of the fuel can offset the aerodynamic load deformation of the leading edge skin, ensuring the aerodynamic lift effect of the unmanned aerial vehicle wing and improving the aerodynamic force.

[0005] The solution adopted by the present invention to solve the technical problem is as follows:

[0006] A detachable structure fuel tank for the leading edge of an unmanned aerial vehicle wing, comprising a connection assembly installed in the wing, a fuel tank body connected to the connection assembly and located on one side of the leading edge of the wing, and a fuel system assembly installed on the fuel tank body; the outer side surface of the fuel tank body is coplanar with the aerodynamic shape surface of the leading edge of the wing and forms the lift characteristic surface of the leading edge of the unmanned aerial vehicle wing.

[0007] In the present invention, a fuel tank is detachably installed inside the leading edge of the wing. Since the load borne by the leading edge of the wing accounts for a relatively small proportion, the connection load between the leading edge of the wing and the wing is small, making it easy to achieve the mechanical connection between the independent leading edge structure and the main wing structure. At the same time, due to the small load borne, the deformation of the fuel tank is small, and the risk of fuel leakage and seepage is small. At the same time, setting the fuel tank inside the leading edge of the wing will increase the weight of the leading edge of the wing, so there is no need to additionally increase the structure to reduce the deformation of the leading edge of the wing. The structure is simple and highly practical.

[0008] In some possible implementation manners, in order to effectively install the fuel tank inside the leading edge of the wing without affecting normal flight;

[0009] The fuel tank body includes a fuel tank skin connected to the connection assembly and coplanar with the aerodynamic profile surface of the leading edge of the wing, and a skeleton assembly that cooperates with the fuel tank skin to form a fuel volume cavity; the cross-section of the fuel tank skin is in a U-shaped structure and cooperates with the skeleton assembly to form a fuel volume cavity with a D-shaped cross-section.

[0010] In some possible implementation manners, in order to effectively achieve the connection between the skeleton assembly, the connecting piece, and the fuel tank skin;

[0011] The skeleton assembly includes a cross beam arranged along the wing span direction, and a rib assembly respectively connected to the cross beam and the fuel tank skin;

[0012] The rib assembly includes an outer rib arranged at the outer end of the cross beam near the leading edge of the wing, an inner rib arranged at the inner end of the cross beam near the leading edge of the wing, and an intermediate rib located between the outer rib and the inner rib; the intermediate rib divides the fuel volume cavity into two volume cavity segments.

[0013] In some possible implementation manners, in order to effectively increase the volume of the fuel volume cavity and effectively achieve the effective connection with the connection assembly;

[0014] The cross-section of the cross beam is in an arch-shaped structure, including an upper flange, an upper turning section, a web, a lower turning section, and a lower flange connected in sequence from top to bottom;

[0015] Wherein, a first card slot with an opening on the side close to the connection assembly is formed between the upper turning section and the upper flange, a second card slot with an opening on the side close to the connection assembly is formed between the lower flange and the lower turning section, and the upper turning section, the web, and the lower turning section are sequentially connected to form a U-shaped groove with an opening facing the leading edge of the wing;

[0016] The outer rib, the inner rib, and the intermediate rib are installed in the U-shaped groove and extend into the fuel volume cavity to be adhesively bonded to the inner side surface of the fuel tank skin; an oil passing hole communicating with the fuel volume cavity is formed between the outer side surface of the intermediate rib and the lower turning section.

[0017] In some possible embodiments, to effectively achieve the connection between the connection component and the fuel tank body;

[0018] The connection component includes a wing front beam arranged along the wing span direction, and two groups of mounting ribs installed on one side of the wing front beam close to the fuel tank body and arranged in parallel; the wing front beam and the two groups of mounting ribs are respectively connected to the fuel tank skin;

[0019] The cross-section of the wing front beam is in a C-shaped structure, and its opening is arranged towards the wing leading edge side and is sleeved with a cross beam; the upper turning section, the web, and the lower turning section extend into the C-shaped structure;

[0020] The fuel tank body is located between the two groups of mounting ribs.

[0021] In some possible embodiments, to make the installation and disassembly of the present invention have good operability;

[0022] The fuel tank skin is provided with a mechanical connection laminate area that is respectively screwed to the wing front beam and the two groups of mounting ribs, a fuel system component installation laminate area for installing fuel system components, and a honeycomb core area.

[0023] In some possible embodiments, to facilitate the sealing operation of the inside of the fuel tank after the fuel tank body is assembled;

[0024] Process holes communicating with the fuel volume cavity are respectively provided on the outer rib, the inner rib, and the web; a sealing cover that is fitted with the process hole is provided on the outer side of the cross beam.

[0025] In some possible embodiments,

[0026] The process holes on the web are multiple and are arranged along the wing span direction, and an annular frame is provided on the inner side of the web corresponding to the multiple process holes one by one.

[0027] In some possible embodiments,

[0028] The outer rib and the inner rib have the same structure, including a connection section sleeved in the U-shaped groove of the cross beam, and an installation section integrally formed with the connection section and extending into the fuel volume cavity to be connected to the fuel tank skin; the cross-section of the installation section is in a C-shaped structure;

[0029] A D-shaped opening and load reduction area is formed between the side away from the U-shaped groove of the middle rib and the inner side surface of the fuel tank skin;

[0030] To ensure that when the fuel tank body is assembled, the contact gaps of the bonding surfaces between the inner rib, the outer rib, the middle rib and the fuel tank skin are uniform and meet the requirements of the bonding adhesive layer thickness;

[0031] In some possible embodiments,

[0032] An outer edge strip connected to the fuel tank skin is provided on the outer side of the installation section and the middle rib, and the width D of the outer edge strip is greater than the thickness d of the outer rib or the inner rib.

[0033] In some possible implementation manners,

[0034] The fuel system assembly includes a breather float valve, a fuel filler base, a breather valve fairing installed outside the breather float valve, an oil drain base, and a fuel pipe joint installed on the fuel tank body;

[0035] The breather float valve, the fuel filler base, and the breather valve fairing are respectively installed above the fuel tank body and on the side of the fuel tank body close to the outer side of the leading edge of the wing; the oil drain base is installed at the bottom of the fuel tank body and on the side of the fuel tank body close to the inner side of the leading edge of the wing; the fuel pipe joint is arranged on the inner rib.

[0036] A forming method for a detachable structure fuel tank at the leading edge of an unmanned aircraft wing specifically includes the following steps:

[0037] Step S1: Laying and curing and forming each component in the fuel tank body;

[0038] Step S2: Drilling holes in each component in the fuel tank body;

[0039] Step S3: Clamping and positioning the fuel tank skin;

[0040] At both ends and the middle position of the fuel tank skin, hold the fuel tank skin with a contour template tooling, then adjust the contour of the fuel tank skin, make process lugs and positioning holes, and then use a pin rod and an inner mold positioning block to expand, press and fix the fuel tank skin on the contour template tooling on the inner surface of the fuel tank skin, thereby completing the clamping and positioning of the fuel tank skin;

[0041] Step S4: Clamping and positioning the skeleton assembly in the fuel tank body;

[0042] Position the inner rib, outer rib, and middle rib through positioning parts;

[0043] Check the gap distribution of the bonding surfaces to be bonded between the inner rib, outer rib, middle rib and the fuel tank skin, and according to the gap distribution, polish the outer side surface of the outer edge strip to control the fitting gap between the bonding surfaces of the inner rib and outer rib and the fuel tank skin within 0.1 - 0.3 mm;

[0044] Evenly apply a room-temperature curing structural adhesive on the bonding surfaces to be bonded between the inner rib, outer rib, middle rib and the fuel tank skin, and clamp the bonding surfaces to be bonded with a bow-shaped clamp;

[0045] Sandpaper-polish the bonding surfaces to be bonded between the cross beam and the fuel tank skin, inner rib, outer rib, middle rib to make the roughness of the bonding surfaces to be bonded meet the bonding process requirements, and position the cross beam;

[0046] Check and control the matching clearance between the cross beam and the fuel tank skin, inner rib, outer rib and middle rib to be glued within 0.1-0.3mm, apply room temperature curing structural adhesive on the cross beam and the fuel tank skin, inner rib, outer rib and middle rib to be glued, and clamp the glued surface with bow clamps;

[0047] Step S5: bonding and curing of the fuel tank skin and frame components at room temperature and non-destructive testing;

[0048] Step S6: Sealing the outer seam of the fuel tank body;

[0049] Through the process holes on the web, inner rib and outer rib, the sealant is evenly applied to the edge of the bonding interface to perform the seam sealing operation of the oil tank;

[0050] Step S7: Install the fuel system components and the sealing cover.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] The present invention can effectively improve the fuel loading capacity of the UAV by designing a detachable mounting structural fuel tank on the leading edge of the wing, and can adapt to the different requirements of large UAVs for fuel loading capacity in different mission configurations. At the same time, the fuel tank has a simple structure, good molding processability, and strong practicality.

[0053] When the wing leading edge structural fuel tank of the present invention is filled with fuel, the deformation of the leading edge skin under the action of aerodynamic load can be offset under the action of gravity, so that the aerodynamic shape of the wing leading edge in flight is more consistent with the designed aerodynamic shape, thereby ensuring the aerodynamic lift effect of the UAV wing and improving the aerodynamic efficiency of the wing;

[0054] In the present invention, the fuel tank is located at the leading edge of the wing and will serve as the load-bearing structure of the wing. It will bear the flight load of the UAV wing together with other structures of the wing. However, the load-bearing load of the leading edge structure of the wing accounts for a relatively small proportion, and the load connecting the leading edge and the wing is small, so it is easy to achieve mechanical connection. At the same time, due to the small load, the deformation of the leading edge fuel tank is small, and the risk of oil leakage and oil seepage of the fuel tank is small.

[0055] The fuel tank in the present invention is detachably mounted on the front beam and mounting rib of the wing, so that the leading edge fuel tank can be completely removed from the wing of the UAV, so as to realize the interchangeability function of the fuel tank and the convenient maintenance and replacement needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 It is a structural schematic diagram of the oil tank in the present invention;

[0057] Figure 2 A schematic diagram of the structure of the fuel tank body, the connection assembly, and the fuel system assembly of the present invention;

[0058] Figure 3 Schematic installation diagram of the fuel tank body and fuel system components in the present invention;

[0059] Figure 4 Schematic structural diagram of the frame assembly in the present invention;

[0060] Figure 5 is Figure 4 Enlarged schematic diagram at position A in

[0061] Figure 6 is Figure 4 Enlarged schematic diagram at position B in

[0062] Figure 7 Cross-sectional view of the middle rib, cross beam, and fuel tank skin in the present invention;

[0063] Figure 8 Cross-sectional view of the inner rib, cross beam, and fuel tank skin in the present invention;

[0064] Wherein: 1. Connection assembly; 11. Wing front beam; 12. Installation rib; 2. Fuel tank body; 21. Fuel tank skin; 22. Frame assembly; 221. Cross beam; 2211. Upper flange; 2212. Upper vertical plate; 2213. Upper horizontal plate; 2214. Web; 2215. Lower horizontal plate; 2216. Lower vertical plate; 2217. Lower flange; 222. Outer rib; 223. Middle rib; 2231. Middle connection section; 2232. Suppression section; 2233. Oil passing hole; 2234. Opening load reduction area; 224. Inner rib; 225. Process hole; 226. Ring-shaped port frame; 220. Outer flange; 3. Fuel system component; 4. Sealing cover; I. Upper turning section; II. Lower turning section; 100. Wing; 200. Wing leading edge. Specific implementation mode

[0065] In the present invention, unless otherwise clearly specified or limited, terms such as "installed", "connected", "joined", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components or the interaction relationship between two components. The "first", "second" and similar terms mentioned in this application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, terms such as "a" or "one" do not indicate a quantity limitation, but indicate that there is at least one. In the implementation of this application, "and / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In the description of the embodiments of this application, unless otherwise stated, the meaning of "a plurality" refers to two or more. For example, a plurality of positioning posts means two or more positioning posts. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] The following is a detailed description of the present invention.

[0067] As Figures 1-8 shown:

[0068] A fuel tank detachably installed on the leading edge 200 of a drone wing, comprising a connection component 1 installed in the wing 100, a fuel tank body 2 connected to the connection component 1 and located on one side of the leading edge 200 of the wing, and a fuel system component 3 installed on the fuel tank body 2; the outer side surface of the fuel tank body 2 is coplanar with the aerodynamic contour surface of the leading edge 200 of the wing and is the lift characteristic surface of the leading edge of the drone wing.

[0069] The fuel tank is detachably installed in the wing 100 and its outer side surface is coplanar with the aerodynamic contour surface of the leading edge 200 of the wing. The reason for setting the fuel tank in this detachable installation position in the present invention is that the load borne by the leading edge 200 of the wing is relatively small, the connection load between the leading edge 200 of the wing and the wing 100 is small, and it is easy to realize the mechanical connection between the independent structure of the leading edge 200 of the wing and the wing 100; at the same time, due to the small load borne, the deformation of the fuel tank is small, and the risk of fuel leakage and seepage of the fuel tank is small; at the same time, setting the fuel tank on the leading edge 200 of the wing will increase the weight of the leading edge 200 of the wing, so there is no need to additionally increase the structure to reduce the deformation amount of the leading edge 200 of the wing; the structure is simple and the practicability is strong.

[0070] In some possible implementation manners, in order to effectively install the fuel tank in the leading edge 200 of the wing and make it not affect normal flight;

[0071] The fuel tank body 2 includes a fuel tank skin 21 connected to the connection assembly 1 and coplanar with the aerodynamic profile of the leading edge 200 of the wing, and a frame assembly 22 that cooperates with the fuel tank skin 21 to form a fuel volume chamber; the cross-section of the fuel tank skin 21 is in a U-shaped structure, and after being adhesively bonded to the frame assembly 22, it forms a fuel volume chamber with a D-shaped cross-section.

[0072] In the present invention, the fuel tank skin 21 is the outer boundary surface of the fuel tank and also serves as the aerodynamic profile feature surface of the leading edge 200 of the wing; the fuel tank skin 21 is a composite part with a honeycomb core structure, which can effectively improve the overall stiffness. The fuel tank skin 21 is provided with a mechanically connected laminate area integrally formed with the connection assembly 1, a fuel system component installation laminate area for installing the fuel system components 3, and a honeycomb core area; among them, the honeycomb core thickness of the honeycomb core area is 4 mm, which is mainly used to increase the bending stiffness of the fuel tank skin 21 and resist deformation caused by oil pressure.

[0073] In some possible implementation manners, in order to effectively realize the connection between the frame assembly 22, the connecting piece, and the fuel tank skin 21;

[0074] The frame assembly 22 includes a cross beam 221 arranged along the length direction of the wing 100, and rib assemblies installed on the cross beam 221 and located inside the fuel tank;

[0075] As Figure 4 shown, the rib assembly includes an outer rib 222 arranged at the outer end of the cross beam 221 close to the leading edge 200 of the wing, an inner rib 224 arranged at the inner end of the cross beam 221 close to the leading edge 200 of the wing, and an intermediate rib 223 located between the outer rib 222 and the inner rib 224.

[0076] The contact surfaces between the fuel tank skin 21 and the inner rib 224, the outer rib 222, and the intermediate rib 223 are secondarily adhesively bonded and cured with structural adhesive to form a fuel volume chamber with a D-shaped cross-section;

[0077] The intermediate rib 223 divides the fuel volume chamber of the fuel tank body 2 into two volume chamber segments.

[0078] In some possible implementation manners, in order to effectively increase the volume of the fuel volume chamber and effectively realize the effective connection with the connection assembly 1;

[0079] As Figure 5 、 Figure 7 shown, the cross-section of the cross beam 221 is in an arch-shaped structure, including an upper flange 2211, an upper turning section I, a web 2214, a lower turning section II, and a lower flange 2217 connected in sequence from top to bottom;

[0080] Wherein, a first slot opening towards the side close to the connecting assembly 1 is formed between the upper turning section I and the upper flange 2211, and a second slot opening towards the side of the leading edge 200 of the wing is formed between the lower flange 2217 and the lower turning section II, that is, the second slot opens towards the side close to the connecting assembly 1. The upper turning section I, the web 2214, and the lower turning section II are sequentially connected to form a U-shaped slot opening towards the side of the leading edge 200 of the wing, that is, the opening of the U-shaped slot is arranged on the side far from the connecting assembly 1;

[0081] Wherein, the outer sides of the upper flange 2211 and the lower flange 2217 are respectively adhesively connected to the inner side of the fuel tank skin 21;

[0082] The outer ribs 222, the inner ribs 224, and the intermediate ribs 223 are installed in the U-shaped slot and extend into the fuel volume cavity and are adhesively connected to the inner side surface of the fuel tank skin 21;

[0083] Furthermore, the inner ribs 224, the outer ribs 222, and the intermediate ribs 223 are adhesively connected to the inner surface of the U-shaped slot through structural adhesive to form the longitudinal and transverse boundary surfaces of the fuel tank.

[0084] In order to ensure that there is no stagnant oil in the entire fuel volume cavity, an oil passage hole 2233 communicating with the fuel volume cavity is formed between the outer side surface of the intermediate rib 223 and the lower turning section II; of course, an oil passage hole 2233 communicating with the fuel volume cavity can also be formed between the outer side surface of the intermediate rib 223 and the upper turning section I;

[0085] The fuel volume cavity is divided into two volume cavity segments by the intermediate rib 223, and the two volume cavity segments are communicated through the oil passage hole 2233, thereby avoiding the existence of stagnant oil in the fuel volume cavity and achieving the purpose of no stagnant oil in the fuel tank body 2;

[0086] In some possible implementation manners, in order to effectively realize the connection between the connecting assembly 1 and the fuel tank body 2;

[0087] The connecting assembly 1 includes a wing front beam 11 arranged along the span direction of the wing 100 and two groups of mounting ribs 12 installed on the side of the wing front beam 11 close to the fuel tank body 2 and arranged in parallel; the wing front beam 11 and the two groups of mounting ribs 12 are respectively connected to the fuel tank skin 21;

[0088] The fuel tank body 2 is located between the two groups of mounting ribs 12, wherein the outer ribs 222 and the inner ribs 224 are located between the two groups of mounting ribs 12;

[0089] The cross-section of the front wing beam 11 is of a C-shaped structure, including an upper wing plate, a middle web plate and a lower wing plate; its opening is arranged towards the leading edge side of the wing and is sleeved with the cross beam 221 of an arch-shaped structure; that is, the upper turning section I, the web plate 2214 and the lower turning section II extend into the C-shaped structure; thereby maximizing the volume of the fuel volume cavity and improving the fuel loading capacity of the fuel tank.

[0090] The upper turning section I includes an upper cross plate 2213 connected to the top of the web plate 2214, an upper vertical plate 2212 connected to the upper cross plate 2213 and parallel to the middle web plate, and the upper edge strip 2211 is connected to the side of the upper vertical plate 2212 away from the upper cross plate 2213.

[0091] The lower turning section II includes a lower cross plate 2215 connected to the bottom of the web plate 2214, a lower vertical plate 2216 connected to the lower cross plate 2215 and parallel to the middle web plate, and the lower edge strip 2217 is connected to the side of the lower vertical plate 2216 away from the lower cross plate 2215; the upper cross plate 2213 and the lower cross plate 2215 are arranged in parallel and cooperate with the web plate 2214 to form a U-shaped groove.

[0092] The outer side surface of the upper edge strip 2211, the outer side surface of the inner side rib 224, the outer side surface of the outer side rib 222, and the outer side surface of the middle rib 223 are used as bonding surfaces to be connected to the inner side surface of the fuel tank skin 21.

[0093] As Figure 8 shown, the web plate 2214 is located inside the C-shaped structure of the front wing beam 11. One end of the upper cross plate 2213 and the lower cross plate 2215 extends into the C-shaped structure of the front wing beam 11 and is connected to the web plate 2214, and the other end of the upper cross plate 2213 and the lower cross plate 2215 extends out of the C-shaped structure of the front wing beam 11 and is connected to the corresponding upper vertical plate 2212 or lower vertical plate 2216.

[0094] The upper wing plate and the lower wing plate of the front wing beam 11 will be located outside the upper cross plate 2213 and the lower cross plate 2215 respectively, and a gap will be formed between them; the fuel tank skin 21 will be screwed to the upper wing plate and the lower wing plate; the outer side surface of the upper cross plate 2213 and the upper wing plate are coplanar to form a surface connected to the inner side surface of the top of the fuel tank skin 21, and the outer side surface of the lower cross plate 2215 and the lower wing plate are coplanar to form a surface connected to the inner side surface of the bottom of the fuel tank skin 21.

[0095] In some possible implementation manners,

[0096] Among the two groups of the mounting ribs 12, the mounting ribs 12 located inside the wing 100 are the inner fuel tank mounting ribs made of aluminum alloy material, and the mounting ribs 12 located outside the wing 100 are the outer fuel tank mounting ribs made of carbon fiber composite laminate; the cross beam 221 is made of carbon fiber laminate.

[0097] The outer side of the mechanical connection laminate area is on the same plane as the outer side of the fuel tank skin. It is the installation and connection functional area of the entire fuel tank on the wing 100, including the front spar flange connection laminate area connected to the front spar 11 of the wing through countersunk bolts and castle nuts, the inner wing fuel tank installation rib connection laminate area connected to the inner fuel tank installation rib through countersunk bolts and castle nuts, and the outer wing fuel tank installation rib connection laminate area connected to the outer fuel tank installation rib through countersunk bolts and castle nuts.

[0098] The inner fuel tank installation rib 12 is located in the inner wing fuel tank installation rib connection laminate area, and the outer fuel tank installation rib 12 is located in the outer wing fuel tank installation rib connection laminate area;

[0099] Countersunk holes are made in the inner wing fuel tank installation rib connection laminate area, and then mechanically connected to the upper wing panel and the lower wing panel through countersunk bolts and castle nut assemblies respectively; countersunk holes are made in the outer wing fuel tank installation rib connection laminate area, and then mechanically connected to the upper wing panel and the lower wing panel through a number of countersunk bolts and castle nut assemblies respectively; at the same time, at the position of the aforementioned mechanical connection area, structural adhesive will also be used for bonding connection after assembly.

[0100] In some possible implementation manners, in order to facilitate the sealing operation of the inside of the fuel tank after the fuel tank body 2 is assembled;

[0101] Process holes 225 for sealing and communicating with the fuel volume cavity are respectively provided on the outer rib 222, the inner rib 224, and the web 2214; the process holes 225 are circular, and the process holes 225 are construction channels for the subsequent sealing operation inside the fuel tank, and are used to apply sealant to the sealing boundary inside the fuel tank body after assembly to perform the out-of-seam sealing operation on the sealing seams of each part of the fuel tank.

[0102] A sealing cover 4 is provided on the outer side of the cross beam 221 and is fitted and installed with the process hole 225.

[0103] Preferably, sealing gaskets are respectively installed between the sealing cover 4 and the outer rib 222, the inner rib 224, and the web 2214.

[0104] In some possible implementation manners, in order to facilitate the application of sealant, the process holes 225 on the web 2214 are multiple and arranged along the span direction of the wing 100;

[0105] Since the cross beam 221 is made of carbon fiber laminate and has a relatively thin thickness, an annular frame 226 corresponding to the multiple process holes 225 one by one is provided on the inner side of the web 2214. The sealing cover 4 is connected to the annular frame 226 through countersunk bolts and airtight castle nut assemblies to ensure the sealing effect. The setting of the annular frame 226 will effectively strengthen the connection between the cross beam 221 and the sealing cover 4.

[0106] In some possible embodiments,

[0107] The outer rib 222 and the inner rib 224 have the same structure, including a connecting section sleeved and installed in the U-shaped groove of the cross beam 221, and an installation section integrally formed with the connecting section and extending into the fuel volume cavity to connect with the fuel tank skin 21; the cross section of the installation section is in a C-shaped structure; the U-shaped groove of the cross beam 221 described here is a U-shaped groove formed by sequentially connecting an upper turning section I, a web 2214, and a lower turning section II with an opening facing the side of the wing leading edge 200;

[0108] In order to effectively reduce the deformation of the fuel tank skin 21 caused by fuel pressure or pressurization, so as to keep the leading edge fuel tank under the action of a large fuel internal pressure during the maneuvering flight of the unmanned aerial vehicle, and the aerodynamic shape of the wing leading edge 200 of the unmanned aerial vehicle can still meet the aerodynamic performance requirements of the unmanned aerial vehicle; the middle rib 223 of the present invention will serve as a deformation suppression rib of the fuel tank body 2; a small chamber is formed between the side of the middle rib 223 far from the cross beam 221 and the inner side of the fuel tank skin 21, and the small chamber is in a D shape and is an opening unloading area 2234;

[0109] Such as Figure 6 、 7 As shown, the middle rib 223 includes a middle connecting section 2231 partially installed in the U-shaped groove and another part extending into the fuel volume cavity, and a suppression section 2232 located in the fuel volume cavity and connected to the middle connecting section 2231. The upper and lower sides of the suppression section 2232 are adhesively bonded to the fuel tank skin 21; a D-shaped opening unloading area 2234 is formed between the side of the suppression section 2232 far from the middle connecting section 2231 and the inner surface of the fuel tank skin 21; oil passing holes 2233 are formed between the side of the suppression section 2232 close to the middle connecting section 2231 and the lower vertical plate 2216 and the upper vertical plate 2212 respectively.

[0110] In order to ensure that when the fuel tank body 2 is assembled, the contact gaps of the adhesive surfaces of the inner rib 224, the outer rib 222, the middle rib 223 and the fuel tank skin 21 are uniform and meet the requirements of the adhesive layer thickness;

[0111] Such as Figure 6 As shown, an outer edge strip 220 adhesively bonded to the fuel tank skin 21 is arranged on the outer sides of the installation section and the middle rib 223, and the width D of the outer edge strip 220 is greater than the thickness d of the outer rib 222 or the inner rib 224.

[0112] In some possible embodiments,

[0113] The fuel system assembly 3 includes a ventilation float valve, a fuel filling port base, a ventilation valve fairing installed outside the ventilation float valve, an oil drain port base, and a fuel pipe joint, which are installed on the fuel tank body 2 and are respectively located in the installation laminate area of the fuel system assembly 3;

[0114] The ventilation float valve, the fuel filling port base, and the ventilation valve fairing are respectively installed above the fuel tank body 2 and on the side of the fuel tank body 2 close to the outside of the leading edge 200 of the wing; the drain port base is installed at the bottom of the fuel tank body 2 and on the side of the fuel tank body 2 close to the inside of the leading edge 200 of the wing; the fuel pipe joint is arranged on the inner rib 224.

[0115] In the present invention, the wing front beam 11 flange connecting laminate area, the inner wing fuel tank installation rib connecting laminate area, and the outer wing fuel tank installation rib connecting laminate area of the fuel tank skin 21 are the installation and connection functional areas of the fuel tank on the wing 100, and are connected to the wing front beam 11, the inner fuel tank installation rib 12, and the outer fuel tank installation rib 12 through countersunk head bolts and plate nuts; at the same time, the disassembly operation is realized through this set of countersunk head bolts. Based on this connection design, the installation and disassembly of the fuel tank of the present invention both have good operability;

[0116] A forming method for a fuel tank detachably installed on the leading edge 200 of an unmanned aerial vehicle wing specifically includes the following steps:

[0117] Step S1: Laying and curing and forming of each component in the fuel tank body;

[0118] For the laying and curing and forming of each component in the fuel tank body 2, the laying operation of each component is carried out on the forming die of each fuel tank part according to the designed laying sequence. The laid parts are moved into the autoclave, and after setting the forming process parameters such as the forming temperature and pressure, curing and forming are carried out for a certain period of time; the components here include the fuel tank skin 21, the cross beam 221, the inner rib 224, the outer rib 222, the middle rib 223, and the sealing cover 4.

[0119] Among them, process lugs are reserved at the front edges of both ends of the fuel tank skin 21, and after curing and demolding, the mold is closed and the film sticking degree is checked;

[0120] The cross beam 221, the inner rib 224, the outer rib 222, and the middle rib 223 are shrunk by 0.5 mm to reserve the demolding springback amount and the thickness of the adhesive layer;

[0121] Step S2: Drilling holes in each component in the fuel tank body;

[0122] Process holes 225 and other fuel component installation holes are made in the cured fuel tank skin 21, cross beam 221, inner rib 224, and outer rib 222;

[0123] Step S3: Clamp and position the fuel tank skin 21 using a positioning fixture. The clamping and positioning described here means: Support the fuel tank skin 21 at both ends and the middle position with a contour template fixture, then adjust the shape of the fuel tank skin 21, fabricate process lugs and positioning holes, and then use pin rods and internal positioning blocks to expand, press, and fix the fuel tank skin 21 on the contour template fixture through the inner surface of the fuel tank skin 21, thus completing the clamping and positioning of the fuel tank skin 21;

[0124] Step S4: Clamp and position the skeleton assembly 22 in the fuel tank body 2;

[0125] The skeleton assembly 22 described here includes a cross beam 221, an inner side rib 224, an outer side rib 222, and a middle rib 223;

[0126] Position the inner side rib 224 and the outer side rib 222 through the two - end positioners, and position the middle rib 223 using a positioning fixture;

[0127] Then check the gap distribution of the bonding surfaces between the inner side rib 224, the outer side rib 222, the middle rib 223 and the fuel tank skin 21, and according to the above - mentioned gap distribution, grind the outer edge strips 220 of the inner side rib 224, the outer side rib 222, and the middle rib 223 to control the mating gap between the bonding surfaces of the inner side rib 224 and the outer side rib 222 and the fuel tank skin 21 within 0.1 - 0.3 mm;

[0128] Evenly apply room - temperature - curing structural adhesive on the bonding surfaces to be bonded between the inner side rib 224, the outer side rib 222, the middle rib 223 and the fuel tank skin 21, and clamp the bonding surfaces to be bonded with an appropriate number of bow - shaped clamps;

[0129] Sand the bonding surfaces to be bonded between the cross beam 221 and the fuel tank skin 21, the inner side rib 224, the outer side rib 222, and the middle rib 223 to make the roughness of the bonding surfaces meet the bonding process requirements, and use a fixture to position the cross beam 221;

[0130] Then check and control the mating gap between the bonding surfaces to be bonded between the cross beam 221 and the fuel tank skin 21, the inner side rib 224, the outer side rib 222, and the middle rib 223 within 0.1 - 0.3 mm, evenly apply room - temperature - curing structural adhesive on the bonding surfaces to be bonded between the cross beam 221 and the fuel tank skin 21, the inner side rib 224, the outer side rib 222, and the middle rib 223, and clamp the bonding surfaces to be bonded with an appropriate number of bow - shaped clamps;

[0131] Step S5: Room - temperature adhesive bonding and curing of the fuel tank skin 21 and the skeleton assembly 22 and non - destructive testing;

[0132] Bond according to the usage specifications of the room-temperature structural adhesive used, and clamp the bonding surfaces of the frame assembly 22 and the fuel tank skin 21 with an appropriate number of bow-shaped clamps to apply an appropriate bonding pressure to the bonding surfaces. After standing for a certain period of time, the structural adhesive cures to form a self-sealing structural fuel tank;

[0133] After the curing and forming are completed, perform non-destructive testing to check for bonding defects, and perform a nail-joining operation on the bonding defect area;

[0134] Step S6: Construction of the external seam seal of the fuel tank body 2;

[0135] Through the process holes 225 on the web 2214, the inner side rib 224, and the outer side rib 222 of the cross beam 221, evenly apply the sealant to the edge line of the bonding interface to perform the external seam seal operation of the fuel tank;

[0136] Step S7: Install the fuel system assembly 3 and the sealing cover 4.

[0137] In the present invention, structural components such as the fuel tank skin 21, the cross beam 221, the inner side rib 224, the outer side rib 222, the intermediate rib 223, and the sealing cover 4 are first cured and formed separately, and then the bonding surfaces of the above structural components are secondarily bonded and cured with structural adhesive to form the fuel tank body 2. Then, through the process holes 225, the sealant is evenly applied to the edge lines of the bonding interfaces of the components to achieve the sealing operation inside the fuel tank body 2; after the application is completed, the process holes 225 are closed by the sealing cover.

[0138] Make mechanical connection bolt holes for the fuel system assembly 3 and the sealing cover 4 on the fuel tank cross beam 221, the fuel tank skin 21, the inner side rib 224, and the outer side rib 222, and install airtight backing nuts, and then install the fuel system assembly 3 and the sealing cover 4 to complete the assembly.

[0139] The present invention is not limited to the foregoing specific embodiments. The present invention extends to any new feature or any new combination disclosed in this specification, as well as any new method or process step or any new combination disclosed.

Claims

1. A detachable structure fuel tank for the leading edge of a drone wing, characterized in that It includes a connection component installed inside the wing, a fuel tank body connected to the connection component and located on one side of the leading edge of the wing, and a fuel system component installed on the fuel tank body; the outer side of the fuel tank body is coplanar with the aerodynamic profile surface of the leading edge of the wing and forms the lift characteristic surface of the leading edge of the UAV wing; the fuel tank body includes a fuel tank skin connected to the connection component and coplanar with the aerodynamic profile surface of the leading edge of the wing, and a skeleton component that cooperates with the fuel tank skin to form a fuel volume cavity; the cross-section of the fuel tank skin is in a U-shaped structure and cooperates with the skeleton component to form a fuel volume cavity with a D-shaped cross-section; the skeleton component includes a cross beam arranged along the wing span direction, and rib components respectively connected to the cross beam and the fuel tank skin; The cross-section of the cross beam is in a bow-shaped structure, including an upper flange, an upper turning section, a web, a lower turning section, and a lower flange connected in sequence from top to bottom; a first slot with an opening on the side close to the connection component is formed between the upper turning section and the upper flange, a second slot with an opening on the side close to the connection component is formed between the lower flange and the lower turning section, and the upper turning section, the web, and the lower turning section are sequentially connected to form a U-shaped groove with an opening facing the leading edge of the wing; The connection component includes a wing front beam arranged along the wing span direction, and two groups of mounting ribs installed on the side of the wing front beam close to the fuel tank body and arranged in parallel; the wing front beam and the two groups of mounting ribs are respectively connected to the fuel tank skin; The cross-section of the wing front beam is in a C-shaped structure, with its opening facing the leading edge side of the wing and sleeved with the cross beam; the upper turning section, the web, and the lower turning section extend into the C-shaped structure; the fuel tank body is located between the two groups of mounting ribs; The fuel tank skin is provided with a mechanical connection laminate area that is respectively screwed to the wing front beam and the two groups of mounting ribs, a fuel system component installation laminate area for installing the fuel system component, and a honeycomb core area; the cross beam is made of carbon fiber laminate.

2. The detachable structure fuel tank at the leading edge of the wing of an unmanned aerial vehicle according to claim 1, characterized in that The rib component includes an outer rib arranged at the outer end of the cross beam close to the leading edge of the wing, an inner rib arranged at the inner end of the cross beam close to the leading edge of the wing, and an intermediate rib located between the outer rib and the inner rib; the intermediate rib divides the fuel volume cavity into two volume cavity segments.

3. The detachable structure fuel tank at the leading edge of the wing of a drone according to claim 2, characterized in that, The outer rib, the inner rib, and the intermediate rib are installed in the U-shaped groove and extend into the fuel volume cavity to be adhesively connected to the inner side surface of the fuel tank skin; an oil passage hole communicating with the fuel volume cavity is formed between the outer side surface of the intermediate rib and the lower turning section.

4. The detachable structure fuel tank at the leading edge of the wing of an unmanned aerial vehicle according to claim 2, characterized in that, Process holes for sealing are respectively arranged on the outer rib, the inner rib, and the web; a sealing cover is arranged on the outer side of the cross beam and is installed in cooperation with the process holes.

5. The detachable structure fuel tank at the leading edge of the wing of an unmanned aerial vehicle according to claim 4, characterized in that There are multiple process holes on the web and they are arranged along the wing span direction, and an annular frame corresponding to the multiple process holes one by one is arranged on the inner side of the web.

6. The detachable structure fuel tank at the leading edge of the wing of a drone according to claim 2, wherein The outer rib and the inner rib have the same structure, including a connection section sleeved and installed in the U-shaped groove of the cross beam, and an installation section integrally formed with the connection section and extending into the fuel volume cavity to be connected to the fuel tank skin; the cross-section of the installation section is in a C-shaped structure; A D-shaped opening load reduction area is formed between the side of the intermediate rib away from the U-shaped groove and the inner side surface of the fuel tank skin; An outer edge strip connected to the fuel tank skin is provided on the outer side of the installation section and the middle rib, and the width D of the outer edge strip is greater than the thickness d of the outer rib or the inner rib.

7. A forming method for a detachable structure fuel tank at the leading edge of a drone wing as described in any one of claims 1 - 6, characterized in that, Specifically, it includes the following steps: Step S1: Laying and curing each component in the fuel tank body; Step S2: Drilling holes in each component in the fuel tank body; Step S3: Clamping and positioning the fuel tank skin; At both ends and the middle position of the fuel tank skin, support the fuel tank skin with a contour template tooling, then adjust the contour of the fuel tank skin, make process lugs and positioning holes, and then use a pin rod and an internal contour positioning block to expand, press and fix the fuel tank skin on the contour template tooling on the inner surface of the fuel tank skin, so as to complete the clamping and positioning of the fuel tank skin; Step S4: Clamping and positioning the frame assembly in the fuel tank body; Position the inner rib, outer rib and middle rib through positioning parts; Check the gap distribution of the bonding surfaces between the inner rib, outer rib and middle rib and the fuel tank skin, and according to the gap distribution, grind the outer side surface of the outer edge strip to control the mating gap between the inner rib and outer rib and the fuel tank skin within 0.1 - 0.3 mm; Evenly apply room temperature curing structural adhesive on the bonding surfaces between the inner rib, outer rib, middle rib and the fuel tank skin, and clamp the bonding surfaces with a fixture; Sand the bonding surfaces between the cross beam and the fuel tank skin, inner rib, outer rib and middle rib to make the roughness of the bonding surfaces meet the bonding process requirements, and position the cross beam; Check and control the mating gap between the cross beam and the bonding surfaces of the fuel tank skin, inner rib, outer rib and middle rib within 0.1 - 0.3 mm, apply room temperature curing structural adhesive on the bonding surfaces between the cross beam and the fuel tank skin, inner rib, outer rib and middle rib, and clamp the bonding surfaces with a fixture; Step S5: Room temperature adhesive bonding and curing and non-destructive testing of the fuel tank skin and frame assembly; Step S6: Construction of external sealing at the seams of the fuel tank body; Through the process holes on the web, inner rib and outer rib, evenly apply the sealant at the edge line of the bonding interface to perform the external sealing operation of the fuel tank; Step S7: Install the fuel system components and sealing covers.

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