A central wing box and an electric tilting helicopter composite wing

Abstract

The present invention provides a central wing box and an electric tilting helicopter composite wing, belonging to the technical field of helicopter structural design. The central wing box adopts a double-beam structure, and includes a load-bearing port cover, a front beam, a rear beam, a lower skin, and wing ribs. The front beam, rear beam, and lower skin together form a battery installation room, which is divided into multiple battery compartments by multiple wing ribs. Each battery compartment is provided with multiple battery mounting bases. The load-bearing port cover is located at the upper part of the battery installation room; the front beam, rear beam, first central wing rib, and second central wing rib are connected to the fuselage. The present invention realizes an integrated wing design, achieves the goal of weight reduction, solves the problem of difficult assembly and adjustment of the fuselage and wing, solves the problem of large opening load transmission caused by battery installation, and the unified specifications of the port cover bolt connection measures greatly improve maintainability.

Description

Technical Field

[0001] The invention belongs to the technical field of helicopter structure design, and in particular relates to a central wing box and an electric tilting helicopter composite material wing. Background Art

[0002] The wing is a crucial component of an aircraft, generating aerodynamic lift and ensuring the aircraft meets the performance and maneuverability requirements specified in the technical specifications. Traditional fixed-wing aircraft wings consist primarily of a left and right wing, symmetrically arranged on either side of the fuselage. Powered by a fuel engine, they require no battery mounting interface.

[0003] The new electric tilt-rotor helicopter combines rotors and wings. In fixed-wing mode during high-speed forward flight, the rotors tilt to act as propellers. In fixed-wing mode, the wings provide lift for the entire aircraft. Because the new electric tilt-rotor helicopter uses electric drive, the central wing box of the wing needs to provide installation interfaces and space for batteries and cables. The large opening in the central wing box required to install the batteries creates significant difficulties in structural force transmission. At the same time, all-composite wings offer advantages in weight reduction, high strength, and high durability. The central wing box design of all all-composite wing structures is a key focus of electric tilt-rotor helicopters. Summary of the Invention

[0004] To address the aforementioned battery pack installation space and the significant difficulty in structural force transmission caused by the large opening structure of the central wing box created for battery installation, the present invention provides a central wing box and an electric tilting helicopter composite wing. This composite wing structure achieves an integrated wing design, achieving the goal of weight reduction, resolving the difficulty in assembling and adjusting the fuselage and wing, and resolving the load transmission problem caused by the large opening due to battery installation. The standardized bolt connection measures for the cover greatly improve maintainability. The technical solution is as follows:

[0005] In the first aspect, a central wing box is provided. The central wing box adopts a double-beam structure and includes a load-bearing cover 20, a front beam 26, a rear beam 27, a lower skin 28, and a rib 21.

[0006] The front beam 26, the rear beam 27 and the lower skin 28 together form a battery installation room, which is divided into multiple battery compartments by multiple wing ribs 21. Each battery compartment is provided with multiple battery mounting bases 29. The load-bearing opening cover 20 is located at the upper part of the battery installation room; the front beam 26, the rear beam 27, the first central wing rib 9, and the second central wing rib 10 are connected to the fuselage.

[0007] Optionally, the front beam 26 and the rear beam 27 are laminated composite parts with a C-shaped cross-section, which are used to reduce weight and transfer the aerodynamic load and axial load of the center wing box; the lower skin 28 is a honeycomb sandwich composite part, which is used to reduce weight and transfer the aerodynamic load and shear load of the center wing box; the lower skin 28 is provided with a maintenance cover and a pipe fixing interface for the environmental control system pipeline to realize the disassembly and maintenance inspection of the environmental control system;

[0008] The first and second center ribs 9 and 10, where the wing meets the fuselage, are constructed from titanium alloy to ensure structural strength. Their coefficient of expansion is similar to that of the composite parts during co-curing, ensuring co-curing quality. The remaining ribs are laminated composite components, reducing weight, increasing structural stability, and transferring the loads of the center wing box. The composite wing design reduces weight by eliminating structural connectors, increasing reliability, and avoiding the assembly difficulties associated with multiple parts, thus reducing overall manufacturing complexity and cost.

[0009] Optionally, the central wing box is connected to the fuselage using a four-point connection. Specifically, the four-point connection is as follows: the first connection point 5 is the front fuselage frame, the center plane of the left web of the front beam, and the first central rib 9, connected by a first bolt; the second connection point 6 is the front fuselage frame, the center plane of the right web of the front beam, and the second central rib 10, connected by a second bolt; the third connection point 7 is the rear fuselage frame, the center plane of the left web of the rear beam, and the first central rib 9, connected by a third bolt; and the fourth connection point 8 is the rear fuselage frame, the center plane of the right web of the rear beam, and the second central rib 10, connected by a fourth bolt. The first and second central ribs 9, 10 are provided with barrel nuts 16 that cooperate with the bolt connection; the heads of the bolts are provided with caps to facilitate the removal of the bolts 13. The present invention provides a clear and simple force transmission path, avoiding the generation of additional bending moments on the rib structure by the bolts. The barrel nuts 16 involved in the bolt connection are installed in the integrated barrel nut supports of the two central ribs 9 and 10 where the wing and fuselage meet. This structure allows for direct force transmission and simple installation and maintenance of the barrel nut, improving wing maintainability compared to traditional wing structures. A cap is provided on the bolt head to facilitate bolt removal.

[0010] Optionally, the bolts at each point in the four-point connection form cooperate with the movable bushing.

[0011] The first bolt and the second bolt are used in conjunction with the movable bushing 17 and the protective bushing 14, and are clearance fit, while the protective bushing 14 and the front center fuselage main frame 11 are interference fit;

[0012] The third and fourth bolts are both used in conjunction with fixed bushings 15, which form an interference fit with the rear center fuselage main frame 12. The fixed bushing connection at the rear end of the center wing box transmits azimuth loads, while the movable bushing connection at the front end allows for adjustment of the assembly clearance, avoiding installation difficulties caused by structural deformation. This combination of fixed and movable bushings allows for adjustment of the assembly clearance of the center wing box in azimuth, facilitating connection and assembly.

[0013] Optionally, the load-bearing port cover 20 is secured to the front beam 26, rear beam 27, and wing rib 21 via bolts 19, support plate nuts 23, and support plate nut washers 22. The support plate nut washers 22 are used to adjust the gap between the threads of the support plate nuts 23 and the sandwich structure, allowing a single-size bolt to be used with sandwich structures of varying thicknesses. The load-bearing port cover transfers the upper skin load and also meets the requirements for battery installation and removal. The use of uniform connectors reduces maintenance costs and significantly improves maintainability.

[0014] Optionally, the main body 24 of the wing rib 21 is made of composite material, while the upper flange 25 of the wing rib 21 is a machined metal flange riveted to the main body 24. The metal flange facilitates the transfer of the compressive load of the connecting bolts, thus reducing weight. The adjustable upper flange design facilitates adjustment of the assembly clearance of the battery load-bearing cover, resolving the difficulty in structural assembly caused by inconsistent assembly clearances.

[0015] Optionally, the battery mounting base 29 is designed to be integrated with the battery ribs to reduce the number of connectors for the battery mounting bracket;

[0016] The battery mounting hole on the battery base adopts a large clearance fit, and the bolts used to connect the battery in the battery mounting hole adopt a floating support nut, which facilitates the adjustment of the gap and avoids the problem of difficulty in battery installation.

[0017] In a second aspect, a composite material wing for an electric tilting helicopter is provided, comprising a central wing box 1 as described in any one of the first aspects, and a left wing assembly 2 and a right wing assembly 3, wherein the wing skeleton is an integrated design, and the wing skeleton is formed by separately forming the central wing box 1 and the left wing assembly 2 and the right wing assembly 3 and then riveting them together through a titanium alloy strip 4;

[0018] The center wing box 1, left wing assembly 2, and right wing assembly 3 are assembled using a two-stage bonding process. Specifically, the front spar 26, rear spar 27, ribs 21, and lower skin 28 of the center wing box 1 are first cured and formed. These components are then assembled using adhesive film bonding before being fully cured in an oven. The strips meet strength and stiffness requirements while allowing for clearance between the left and right wing boxes to ensure adjustable clearance. The use of inner strips enhances overall aesthetics and prevents corrosion of the outer strips from harsh environmental conditions, further enhancing structural reliability.

[0019] Optionally, the two sides of the central wing box are connected to the nacelle structure by using a double-ear joint 30, and a double-ear joint movable bushing 31 is provided in the double-ear joint to facilitate the adjustment of the installation gap; the double-ear joint is also used to connect the equipment for hoisting the wing, avoiding the need to add a separate ground protection equipment joint, and the functional integration greatly reduces the weight of the structure.

[0020] Optionally, a detachable fairing 32 is provided at the leading edge of the central wing box, which not only realizes the aerodynamic fairing function but also realizes the disassembly and maintenance inspection function of the cables inside the leading edge;

[0021] The front and rear flanges of the central wing box are provided with fixed fairings 33, which are formed by riveting the front and rear skins together, providing a cable conduit channel for the battery cables and enabling the cables to be easily assembled and disassembled.

[0022] The beneficial effects of the present invention are at least:

[0023] The wing frame is integrated into the design, and the central wing box adopts a composite material structure, which greatly reduces the weight;

[0024] The wing molding process design uses a secondary bonding molding method for each wing section, which avoids the assembly difficulties caused by the original multi-part assembly and reduces the overall processing difficulty and cost;

[0025] The central wing box features simple and efficient installation, easy disassembly and installation, high reliability, and a clear and simple force transmission path, eliminating the generation of additional bending moments on the wing rib structure by bolts. The fixed bushing combined with the movable bushing assembly scheme allows for adjustment of the wing assembly clearance in the heading direction, facilitating connection and assembly.

[0026] The central wing rib wing, barrel nut support, and battery mounting support that connect to the fuselage in the central wing box are integrated into one design, and titanium alloy metal parts ensure structural strength;

[0027] The central wing box load-bearing cover not only achieves load transfer, but also effectively integrates the battery pack with the wing structure, facilitating clearance adjustment and avoiding battery installation difficulties. The central wing box load-bearing cover has a single mounting bolt specification, making it easy to disassemble and install.

[0028] The central wing box composite rib design uses a composite body riveted to a metal flange, ensuring connection strength and providing assembly adjustment space. The central wing box composite rib design solves the structural assembly difficulties caused by inconsistent assembly clearances.

[0029] The central wing box is connected to the nacelle structure with double-ear connectors on both sides, eliminating the need for separate ground protection equipment connectors. This functional integration significantly reduces the weight of the structure.

[0030] The design of the central wing box fairing enables the disassembly and maintenance inspection of the cables inside the leading edge while providing aerodynamic fairing. The lower skin of the central wing box enables the disassembly and maintenance inspection of the environmental control system.

[0031] The central wing box structure of the electric tilt helicopter of the present invention solves the installation space problem of the battery pack and ensures the strength and reliability of the connection between the central wing box and the fuselage. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of a wing skeleton structure provided by an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of the structure of the connection between the central wing box and the fuselage provided in an embodiment of the present invention;

[0034] Figure 3 A schematic diagram illustrating the connection between the protective bushing and the front center fuselage main frame provided by an embodiment of the present invention;

[0035] Figure 4 A schematic diagram of the connection between the fixed bushing and the rear center fuselage main frame provided by an embodiment of the present invention;

[0036] Figure 5 A schematic diagram of the connection points of the load-bearing opening cover provided in an embodiment of the present invention;

[0037] Figure 6 A schematic diagram of the connection of the load-bearing cover provided in an embodiment of the present invention;

[0038] Figure 7 A schematic diagram of a rib upper flange provided in an embodiment of the present invention;

[0039] Figure 8 A schematic diagram of a double-ear connector provided in an embodiment of the present invention;

[0040] Figure 9 A schematic diagram of the wing lower skin provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0041] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work are within the scope of protection of the present invention.

[0042] The features and illustrative embodiments of various aspects of the present invention will be described in detail below. In the detailed description below, many specific details are proposed in order to provide a comprehensive understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention can be implemented without the need for some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the present invention. The present invention is in no way limited to any specific arrangement and method proposed below, but rather encompasses any improvements, replacements, and modifications to structures, methods, and devices without departing from the spirit of the present invention. In the accompanying drawings and the following description, well-known structures and techniques are not shown to avoid unnecessary ambiguity in the present invention.

[0043] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other, and the various embodiments may refer to and quote each other.

[0044] The present invention is further described in detail below through specific implementation methods and drawings.

[0045] The present invention provides a central wing box and a composite wing for an electric tilting helicopter. The composite wing structure realizes an integrated wing design, achieves the goal of weight reduction, solves the problem of difficult assembly and adjustment of the fuselage and wing, solves the problem of large opening load transmission caused by battery installation, and adopts a unified specification of cover bolt connection measures, which greatly improves maintainability.

[0046] In the present invention, the wing frame is designed as an integrated whole. The wing frame is formed by the central wing box 1 and the left wing assembly 2 and the right wing assembly 3, which are then riveted together by titanium alloy strips 4. Figure 1 、 Figure 2 The three-section wing skeleton design addresses the autoclave size requirements of the process and avoids assembly difficulties caused by large deformation of large parts. It represents a trade-off between functional performance and economic efficiency. The titanium alloy strip plate 4 meets the strength and stiffness requirements while leaving a gap between the left and right wing boxes to ensure adjustable installation clearance. The use of an inner strip plate creates an overall aesthetic, avoids corrosion problems caused by the harsh external environment of the outer strip plate, and further enhances the reliability of the structure.

[0047] The central wing box molding process is designed to use a secondary bonding molding method for each section of the wing assembly, that is, the central wing box 1 is first subjected to a secondary bonding molding method with the left wing assembly 2 and the right wing assembly 3. Specifically, the front beam 26, rear beam 27, wing ribs 21 and lower skin 28 of the central wing box 1 are first solidified and molded. The central wing box adopts a double-beam structure, with the front beam 26 and rear beam 27 of the wing being laminated composite parts, and the lower skin 28 of the wing being a honeycomb sandwich composite part. Except for the central ribs 9 and 10 where the wing connects to the fuselage, the remaining ribs 21 are laminated composite parts. The composite material wing structure design reduces structural connectors in terms of weight reduction, increases reliability, avoids the assembly difficulties caused by the original multi-part assembly, and reduces the overall processing difficulty and cost.

[0048] The central wing box is connected to the fuselage using a four-point connection. Figure 2 . The four-point connection form is specifically as follows: the first connection point 5 is the front frame of the fuselage, the center plane of the left web of the front beam, and the central wing rib 9, which are connected by the first bolt; the second connection point 6 is the front frame of the fuselage, the center plane of the right web of the front beam, and the central wing rib 10, which are connected by the second bolt; the third connection point 7 is the rear frame of the fuselage, the center plane of the left web of the rear beam, and the central wing rib 9, which are connected by the third bolt; the fourth connection point 8 is the rear frame of the fuselage, the center plane of the right web of the rear beam, and the central wing rib 10, which are connected by the fourth bolt; the central wing rib 9 and the central wing rib 10 are provided with a cylindrical nut 16 for matching bolt connection; a cap is provided on the head of the bolt to facilitate the disassembly of the bolt 13. The force transmission path of this four-point connection form is clear and simple, which avoids the generation of additional bending moment on the wing rib structure by the bolt. The central wing ribs 9 and 10 where the wing and the fuselage are connected are made of titanium alloy metal parts to ensure structural strength. The expansion coefficient is relatively close to that of the composite parts during co-curing molding, ensuring the quality of co-curing. This structural form transmits force directly, and the barrel nut is easy to install and maintain. Compared with traditional wing structures, it improves the maintainability of the wing.

[0049] The center wing box assembly gap adjustment, the first bolt and the second bolt are used in conjunction with the movable bushing 17 and the protective bushing 14, and are clearance fit, the protective bushing 14 and the front center fuselage main frame 11 are interference fit, see Figure 3 The third bolt and the fourth bolt are used in conjunction with the fixed bushing 15. The fixed bushing 15 and the rear middle fuselage main frame 12 are interference fit. Figure 4 The fixed bushing at the rear end of the wing transmits the azimuth load, while the movable bushing at the front end allows for adjustment of the assembly clearance, avoiding installation difficulties caused by structural deformation. The fixed bushing combined with the movable bushing allows for adjustment of the wing's azimuth assembly clearance, facilitating connection and assembly.

[0050] The central wing box load-bearing cover design, the battery is installed in the rib cavity of the central wing assembly, the load-bearing cover connection point 18, see Figure 5 To meet the requirements of battery pack disassembly and assembly, the load-bearing cover 20 is fixed to the front beam 26, rear beam 27 and wing rib 21 by bolts 19, support plate nuts 23 and support plate nut washers 22. Figure 6 To ensure uniformity of parts, a support nut washer 22 is used to adjust the gap between the support nut 22 thread and the sandwich structure, allowing a single-size bolt to be used in sandwich structures of varying thicknesses. The load-bearing port cover transfers the upper skin load and meets the requirements for battery installation and removal. The load-bearing port cover utilizes connectors of uniform specifications, reducing maintenance costs and significantly improving maintainability.

[0051] The central wing box is designed with composite wing ribs. The battery mounting base 29 is integrated with the central wing ribs 9 and 10 where the wing and fuselage meet to reduce the number of connectors for the battery mounting bracket. Figure 2 The battery mounting holes on the battery base are fitted with a large clearance, and the bolts used to connect the batteries in the battery mounting holes are fitted with floating support nuts, which facilitates the adjustment of the clearance and avoids the problem of difficult battery installation. The main part of the rib 21 of the central wing assembly is made of composite materials. The upper flange 25 of the rib 21 is riveted to the main part 24 by riveting a metal machined flange. Figure 7 The metal flange facilitates the transfer of the extrusion load from the connecting bolts, reducing weight. The adjustable upper flange design facilitates adjustment of the assembly gap size of the battery load-bearing cover, resolving the structural assembly difficulties caused by inconsistent assembly gaps.

[0052] The two sides of the central wing box are connected to the nacelle structure with double-ear joints 30. Double-ear joint movable bushings 31 are set in the double-ear joints to facilitate the adjustment of the installation gap. The double-ear joints 30 are also used to connect the equipment for hoisting the wing, avoiding the need to add a separate ground protection equipment joint. The functional integration greatly reduces the weight of the structure. Figure 8 .

[0053] A detachable fairing 32 is provided at the leading edge of the central wing box. The detachable fairing not only realizes the aerodynamic fairing function but also realizes the disassembly and maintenance inspection functions of the cables inside the leading edge. Fixed fairings 33 are provided at the front and rear flanges of the central wing box. The fixed fairings 33 are formed by riveting the front and rear skins, providing a cable conduit channel for the battery cables and realizing the disassembly and assembly of the cables. Figure 8 Because batteries are prone to high temperatures during long-term use, an environmental control system is required to achieve temperature control. The wing lower skin 28 is equipped with a maintenance cover and a pipe fixing interface 34 for the environmental control system pipes, which enables the disassembly and maintenance inspection of the environmental control system. Figure 9 .

[0054] The above merely describes the embodiments of the present invention, and while the description is relatively specific and detailed, it should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the scope of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Furthermore, any portions not described in detail herein are conventional techniques.

Claims

1. A central wing box, characterized in that: The central wing box adopts a double beam structure, and includes a load-bearing cover (20), a front beam (26), a rear beam (27), a lower skin (28), and a wing rib (21). The front beam (26), the rear beam (27) and the lower skin (28) together form a battery installation room, which is divided into a plurality of battery compartments by a plurality of wing ribs (21), each battery compartment is provided with a plurality of battery installation bases (29), and a load-bearing opening cover (20) is located at the upper part of the battery installation room; the front beam (26), the rear beam (27), the first central wing rib (9), and the second central wing rib (10) are connected to the fuselage; The central wing box is connected to the fuselage in a four-point connection form. Specifically, the four-point connection form is as follows: the first connection point (5) is the fuselage front frame, the left side web center plane of the front beam, and the first central wing rib (9) are connected by a first bolt; the second connection point (6) is the fuselage front frame, the right side web center plane of the front beam, and the second central wing rib (10) are connected by a second bolt; the third connection point (7) is the fuselage rear frame, the left side web center plane of the rear beam, and the first central wing rib (9) are connected by a third bolt; the fourth connection point (8) is the fuselage rear frame, the right side web center plane of the rear beam, and the second central wing rib (10) are connected by a fourth bolt. connection; the first central wing rib (9) and the second central wing rib (10) are provided with a cylindrical nut (16) connected with a matching bolt; the head of the bolt is provided with a cap for facilitating the removal of the bolt (13); the bolt at each point in the four-point connection form is matched with a bushing, the first bolt and the second bolt are used in conjunction with the movable bushing (17) and the protective bushing (14), and are clearance-matched, and the protective bushing (14) and the front middle fuselage main frame (11) are interference-matched; the third bolt and the fourth bolt are used in conjunction with the fixed bushing (15), and the fixed bushing (15) and the rear middle fuselage main frame (12) are interference-matched; The front beam (26) and the rear beam (27) are laminated composite parts with a C-shaped cross section; the lower skin (28) is a honeycomb sandwich composite part; the lower skin (28) is provided with a maintenance cover and a pipe fixing interface for the environmental control system pipeline; the first central rib (9) and the second central rib (10) for connecting the wing and the fuselage are made of titanium alloy metal parts; the remaining ribs are laminated composite parts; The load-bearing opening cover (20) is fixed on the front beam (26), the rear beam (27) and the wing rib (21) through bolts (19), support plate nuts (23) and support plate nut washers (22); The main body (24) of the wing rib (21) is made of composite material, and the upper flange (25) of the wing rib (21) is a metal machined flange and is riveted to the main body (24).

2. The center wing box according to claim 1, characterized in that: The battery mounting base (29) is designed to be integrated with the battery wing rib; the battery mounting hole on the battery mounting base adopts a large clearance fit, and the bolts in the battery mounting hole for connecting with the battery adopt a floating support plate nut.

3. An electric tilt helicopter composite wing, characterized in that: The invention comprises the central wing box (1) as claimed in claim 1, and the left wing assembly (2) and the right wing assembly (3), wherein the wing skeleton is designed as an integrated whole, and the wing skeleton is composed of the central wing box (1) and the left wing assembly (2) and the right wing assembly (3) which are respectively formed and then riveted together by titanium alloy strips (4); The central wing box (1) and the left wing assembly (2) and the right wing assembly (3) are formed by a secondary bonding method, specifically: firstly, the front beam (26), the rear beam (27), the wing rib (21) and the lower skin (28) of the central wing box (1) are subjected to part curing and forming, and then these parts are assembled by film bonding and then put into a furnace for medium-temperature curing and forming as a whole; The two sides of the central wing box are connected to the nacelle structure by using double-ear joints (30), and double-ear joint movable bushings (31) are arranged in the double-ear joints; the double-ear joints are also used to connect equipment for hoisting the wings.

4. The electric tilt helicopter composite wing according to claim 3, characterized in that: A detachable fairing (32) is provided at the leading edge of the central wing box; The front and rear flanges of the central wing box are provided with fixed fairings (33), which are formed by riveting the front and rear skins.

Images