Embedded special-shaped pressure-bearing auxiliary oil tank

Abstract

The embedded special-shaped pressure-bearing auxiliary fuel tank comprises a right skin, an upper skin, a left skin and a lower skin which are sequentially arranged on the peripheral side, and a front skin and a rear skin which are located at the two ends, and the adjacent skins are welded through friction stir welding; the right skin, the upper skin, the left skin and the lower skin are mutually overlapped and positioned to define a structure with a square section, annular grooves are respectively formed in two ends of the structure, and the front skin and the rear skin are respectively placed in the annular grooves to form a box section structure. The left skin and the right skin respectively comprise two end surfaces which are connected at an obtuse angle, and reinforcing ribs are arranged between the adjacent end surfaces; and the front skin and the rear skin are respectively and correspondingly of special-shaped structures. The invention has the advantages of stable pressure bearing, high connection strength, small number of weld joints, small welding deformation, reliable sealing, long fatigue life, light weight, good appearance quality, better guarantee of interface precision, good economical efficiency and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of an embedded auxiliary fuel tank for an aircraft, and particularly relates to an embedded auxiliary fuel tank with a special shape. BACKGROUND

[0002] It is necessary for an aircraft to be equipped with a hanging object, such as an auxiliary fuel tank. With the increasing requirements for flight performance of an aircraft, the hanging structure of the aircraft gradually develops from an external hanging type to an internal built-in type. The internal built-in type is an essential structure of a future aircraft. Accordingly, new requirements are proposed for the use of the auxiliary fuel tank. The structure of the auxiliary fuel tank needs to be changed from the external hanging type to the internal built-in type. In addition, in order to achieve the multifunctional application of a mission compartment of the aircraft, the internal built-in auxiliary fuel tank needs to be able to fully utilize the space of the mission compartment to store fuel, so as to increase the range of the aircraft. Since the mission compartment is usually openable and closable and has a compartment door driving mechanism inside, the conventional round fuel tank or square fuel tank cannot fully utilize the space of the mission compartment, resulting in a reduced fuel storage capacity. Therefore, the auxiliary fuel tank needs to be designed to have a special shape that matches the special shape of the mission compartment.

[0003] At present, all the auxiliary fuel tanks applied at home and abroad are round, and there is no application example of an embedded auxiliary fuel tank with a special shape. If the embedded auxiliary fuel tank with a special shape adopts the traditional structure form of a framework frame beam first and a skin plate argon arc welding later, a large number of ribs need to be welded inside the skin in order to ensure the pressure resistance performance. As a result, there are a large number of welds and a large number of longitudinal and transverse intersections. The thin skin is unevenly heated during the welding process, and is prone to defects such as weld penetration, hot cracking and depression. The weld quality is poor, the interface precision is difficult to guarantee, the sealing reliability and fatigue life of the auxiliary fuel tank are reduced, and the weight is heavy. If a composite auxiliary fuel tank structure form is adopted, the price of the composite raw material is more than 10 times that of a commonly used metal (such as an aluminum alloy). The composite material needs to be laid by using a special non-standard mold, resulting in poor economic efficiency. The composite material is a non-dense body and has low electrical conductivity. A sealing coating and an electrostatic coating need to be sprayed in order to meet the fuel storage requirements. The coating cannot meet the use in the whole life cycle and needs to be maintained regularly, which is time-consuming and labor-consuming. SUMMARY

[0004] The purpose of the present application is to provide an embedded auxiliary fuel tank with a special shape.

[0005] The present application is mainly realized by the following technical solutions. An embedded auxiliary fuel tank with a special shape comprises right skin, upper skin, left skin and lower skin arranged in sequence on the circumference, and front skin and rear skin at both ends, and adjacent skins are welded by friction stir welding. The right skin, the upper skin, the left skin and the lower skin are positioned and surrounded to form a structure with a cross section in the shape of a mouth, and both ends form annular grooves. The front skin and the rear skin are respectively placed in the annular grooves to form a box segment structure. The cross section of the overlapping area of the adjacent skins is trapezoidal step shape, and the inner sides of the right skin, the upper skin, the left skin, the lower skin, the front skin and the rear skin are integrally formed with stiffeners; the left skin and the right skin each comprise two end faces connected at an obtuse angle, and the stiffeners are arranged between the adjacent end faces; the front skin and the rear skin each correspond to a special-shaped structure.

[0006] In order to better realize the present application, further, the stiffeners comprise main stiffeners and auxiliary stiffeners, and the skins are provided with a plurality of main stiffeners in the short edge direction and a plurality of auxiliary stiffeners in the long edge direction according to the shortest force transmission path principle, for preventing structural instability; the number of the auxiliary stiffeners is less than the number of the main stiffeners.

[0007] In order to better realize the present application, further, the height of the main stiffeners located in the middle is greater than the height of the main stiffeners located at the two ends, so as to ensure the gas pressure stiffness and strength of the skin.

[0008] In order to better realize the present application, further, the left skin and the right skin each correspond to an L-shaped structure, and the adjacent end faces are at an obtuse angle, a plurality of main stiffeners are arranged between the inner sides of the adjacent end faces, and a plurality of transition stiffeners are arranged between the adjacent main stiffeners; the lower ends of the front skin and the rear skin each correspond to a matching bevel.

[0009] In order to better realize the present application, further, the two ends of the left skin and the right skin each are provided with a step structure, so as to form a ring-shaped groove.

[0010] In order to better realize the present application, further, the stiffeners on the front skin and the rear skin correspond to trapezoidal cross sections, and the stiffeners are perpendicular to the inner wall surface of the skin, and the connection part of the stiffener and the skin adopts a round corner transition.

[0011] In order to better realize the present application, further, the inner sides of the upper skin and the lower skin each are integrally formed with stiffeners and local rib strips; the upper skin and the lower skin each are provided with a functional interface mounting hole.

[0012] In order to better realize the present application, further, the right skin, the upper skin, the left skin, the lower skin, the front skin and the rear skin are each prepared from high-strength aluminum alloy with a brand of 7075-T651.

[0013] The present application has the following beneficial effects: The skin in the application is assembled and positioned mutually, and forms a box segment structure by mutual lap joint support, and is connected by friction stir welding, so that the oil tank structure is stable, the inner support process positioning tool and special non-standard mold are saved, and the application has the advantages of high connection strength, small number of welds, small welding deformation, reliable sealing, long fatigue life and the like. Specifically, the skin in the application is integrally formed by a metal plate, has a special shape, and has a rib inside, the skin adopts variable cross-section design to match the stiffness and strength requirements of different regions, and has the advantages of light weight and high interface precision. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 Fig. 1 is a structural schematic view of an inner buried special-shaped pressure-bearing auxiliary oil tank according to the application; Figure 2 Fig. 2 is a structural schematic view of a lower skin; Figure 3 Fig. 3 is a structural schematic view of an upper skin; Figure 4 Fig. 4 is a structural schematic view of a left skin; Figure 5 Fig. 5 is a structural schematic view of a right skin; Figure 6 Fig. 6 is a structural schematic view of a front skin; Figure 7 Fig. 7 is a structural schematic view of a rear skin; Figure 8 Fig. 8 is a schematic view of a friction welding seam of the inner buried special-shaped pressure-bearing auxiliary oil tank according to the application; Figure 9 Fig. 9 is a structural schematic view of a ring-shaped groove; Figure 10 Fig. 10 is a structural schematic view of mutual assembly and positioning of adjacent skin lap joint areas.

[0015] Wherein: 1-lower skin, 2-upper skin, 3-left skin, 4-right skin, 5-front skin, 6-rear skin. DETAILED DESCRIPTION

[0016] In the description of the application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the application is usually placed, and are only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.

[0017] In addition, in the description of the present application, the terms "horizontal", "vertical" and the like do not mean that the components must be absolutely horizontal or vertical, but can be slightly inclined. For example, "horizontal" only means that it is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0018] In the description of the present application, it should also be noted that, unless otherwise specified and limited, if the terms "arrangement", "installation", "connection", "connection" appear, they should be understood broadly, for example, they can be fixedly connected, or can be detachably connected, or integrally connected; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium; can be connected inside two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0019] Embodiment 1: An inner-embedded special-shaped pressure-bearing auxiliary fuel tank, as shown in Figure 1 , comprises an upper skin 2, a lower skin 1, a left skin 3, a right skin 4, a front skin 5 and a rear skin 6, the skins are integrally formed by a plurality of metal sheets, and the skins are provided with reinforcing ribs for increasing the structural rigidity of the skins. As shown in Figure 10 , the overlapping area between adjacent skins is trapezoidal in cross-section, can be mutually assembled and positioned, and can be mutually supported to form a box section structure, as shown in Figure 8 , and then welded into an auxiliary fuel tank by friction stir welding.

[0020] Preferably, the material of the skin is high-strength aluminum alloy with a grade of 7075-T651.

[0021] Preferably, as shown in Figure 2 and Figure 3 , the inner sides of the upper skin 2 and the lower skin 1 are integrally formed with reinforcing ribs and local ribs; the upper skin 2 and the lower skin 1 are respectively provided with functional interface mounting holes.

[0022] Preferably, as shown in Figure 4~Figure 7 , the reinforcing ribs comprise main reinforcing ribs and auxiliary reinforcing ribs, according to the principle of shortest force transmission path, the skin is provided with a plurality of main reinforcing ribs in the short edge direction, and a plurality of auxiliary reinforcing ribs in the long edge direction, for preventing structural instability; the number of auxiliary reinforcing ribs is less than the number of main reinforcing ribs. Further, the height of the main reinforcing ribs located in the middle is greater than the height of the main reinforcing ribs located at both ends, so as to ensure the gas pressure rigidity of the skin.

[0023] Preferably, as shown in Figure 4 and Figure 5As shown in the drawings, the left skin 3 and the right skin 4 are respectively L-shaped structures, and the adjacent end faces are obtuse angles, and a plurality of main reinforcing ribs are arranged between the inner sides of the adjacent end faces, and a plurality of transition reinforcing ribs are arranged between the adjacent main reinforcing ribs; the lower ends of the front skin 5 and the rear skin 6 are respectively provided with corresponding bevels, and the shapes of the front skin 5 and the rear skin 6 are special shapes. Figure 9 As shown in the drawings, the left skin 3 and the right skin 4 are respectively provided with step structures at the two ends to enclose annular grooves.

[0024] Preferably, as shown in the drawings, Figure 6 and Figure 7 As shown in the drawings, the reinforcing ribs on the front skin 5 and the rear skin 6 are trapezoidal in cross section, and the reinforcing ribs are perpendicular to the inner wall of the skin, and the connecting part of the reinforcing rib and the skin adopts a round corner transition.

[0025] In the assembly process, each skin is integrally formed from a metal plate, has a special shape, and has a rib integrally formed inside, the skin adopts a variable cross-section design to match the stiffness and strength requirements of different areas, has the advantages of light weight and high interface precision. Then, the skins on the periphery are positioned and spliced through trapezoidal steps, and the front skin 5 and the rear skin 6 are positioned and installed through annular grooves, and finally the auxiliary fuel tank is welded by friction stir welding. Compared with the prior art, the present application has the advantages of stable pressure bearing, high connection strength, few welds, small welding deformation, reliable sealing, high fatigue life, light weight, good appearance quality, better interface precision, good economy and the like.

[0026] The above is only a preferred embodiment of the present application, and does not limit the present application in any form, and any simple modification or equivalent change made according to the technical essence of the present application to the above embodiment falls within the protection scope of the present application.

Claims

1. An embedded special-shaped pressure-bearing auxiliary fuel tank, characterized in that, The right skin (4), the upper skin (2), the left skin (3) and the lower skin (1) are sequentially arranged on the circumference, and the front skin (5) and the rear skin (6) are arranged at the two ends, and the adjacent skins are welded by friction stir welding; the right skin (4), the upper skin (2), the left skin (3) and the lower skin (1) are positioned and surrounded to form a structure with a cross-section in the shape of a mouth, and the two ends form annular grooves, respectively, and the front skin (5) and the rear skin (6) are placed in the annular grooves, respectively, to form a box section structure. The cross section of the overlapping area of the adjacent skins is in the shape of a trapezoidal step, the inner sides of the right skin (4), the upper skin (2), the left skin (3), the lower skin (1), the front skin (5) and the rear skin (6) are integrally formed with reinforcing ribs, respectively; the left skin (3) and the right skin (4) respectively include two end faces connected at an obtuse angle, and the reinforcing ribs are arranged between the adjacent end faces; the front skin (5) and the rear skin (6) are respectively in the shape of a special structure.

2. The inner-embedded shaped pressure-bearing auxiliary fuel tank according to claim 1, characterized in that, The reinforcing ribs include main reinforcing ribs and auxiliary reinforcing ribs, and according to the shortest force transmission path principle, the skins are provided with a plurality of main reinforcing ribs in the short edge direction and a plurality of auxiliary reinforcing ribs in the long edge direction to prevent structural instability; the number of the auxiliary reinforcing ribs is less than the number of the main reinforcing ribs.

3. The recessed shaped pressure-bearing auxiliary fuel tank according to claim 2, characterized in that, The height of the main reinforcing ribs located in the middle is greater than the height of the main reinforcing ribs located at the two ends to ensure the gas pressure stiffness of the skin.

4. The recessed shaped pressure-bearing auxiliary fuel tank according to claim 2 or 3, characterized in that, The left skin (3) and the right skin (4) are respectively in the shape of an L structure, and the adjacent end faces are at an obtuse angle, a plurality of main reinforcing ribs are arranged between the inner sides of the adjacent end faces, and a plurality of transition reinforcing ribs are arranged between the adjacent main reinforcing ribs; the lower ends of the front skin (5) and the rear skin (6) are respectively provided with bevels that fit each other.

5. The recessed shaped pressure-bearing auxiliary fuel tank according to claim 4, characterized in that, The two ends of the left skin (3) and the right skin (4) are respectively provided with step structures to form annular grooves.

6. The inner-embedded shaped pressure-bearing auxiliary oil tank according to any one of claims 1-3, characterized in that, The reinforcing ribs on the front skin (5) and the rear skin (6) are in the shape of a trapezoidal cross section, and the reinforcing ribs are perpendicular to the inner wall of the skin, and the connection part of the reinforcing rib and the skin adopts a round corner transition.

7. The recessed shaped pressure-bearing auxiliary fuel tank according to claim 1, characterized in that, The inner sides of the upper skin (2) and the lower skin (1) are integrally formed with reinforcing ribs and local ribs, respectively; the upper skin (2) and the lower skin (1) are respectively provided with functional interface mounting holes.

8. The recessed shaped pressure-bearing auxiliary fuel tank according to claim 1, characterized in that, The right skin (4), the upper skin (2), the left skin (3), the lower skin (1), the front skin (5) and the rear skin (6) are all made of high-strength aluminum alloy with a brand of 7075-T651.

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