Buffering and energy-absorbing ducted fan shell structure

Abstract

The invention discloses a buffering and energy-absorbing ducted fan shell structure which comprises a paper folding structure, an elastic hinge, a sliding rail, a supporting plate, a ducted outer wall, a ducted inner wall, an inner energy-absorbing layer and an outer energy-absorbing layer. The duct outer wall firstly deforms and absorbs energy; then the internal energy absorption unit, the inner energy absorption layer and the outer energy absorption layer further absorb energy and disperse loads; the inner wall of the duct provides support; wherein the paper folding structure provides rigid support and load dispersion, and the elastic hinge coordinates deformation of the paper folding structure, so that the elastic hinge can drive the paper folding structure to deform, a load transmission path is optimized, and the problem that load transmission is discontinuous when the paper folding structure impacts is solved; the inner energy absorption layer and the outer energy absorption layer are filled with TPU foam materials and PMI foam materials respectively, so that the energy absorption effect is enhanced, and the structural stability can be maintained to a certain extent.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ducted fan, and particularly relates to a buffer energy-absorbing ducted fan shell structure. BACKGROUND

[0002] The ducted aircraft is widely applied in the fields of aerial photography, rescue task, logistics transportation, power inspection and the like due to its compact structure, high safety and good aerodynamic efficiency. However, in the actual operation process, the ducted unmanned aerial vehicle is easily affected by external impact (such as suddenly encountering an obstacle in flight), which leads to damage of components, affects the normal work of the unmanned aerial vehicle and even causes a safety accident, and therefore a protection structure needs to be designed to protect the core components of the duct, so as to ensure the stability of the aircraft power to maintain normal flight. Therefore, the ducted fan skin needs to have the functions of anti-impact deformation and energy absorption, and the rigidity of the inner wall of the duct needs to be stable to maintain the gap between the tips of the ducted fan and prevent the propeller from being scraped with the skin to cause structural damage.

[0003] The existing duct skin is mostly made of metal or brittle composite material, although it has basic protection ability, but poor flexibility, easy to break under impact, poor energy absorption effect, and impact load is directly transmitted to the internal structure. Common buffer energy absorption structures mostly use foam sandwich structure, paper folding sandwich structure, and duct support structure similar to the internal frame of the wing. Some of the currently published duct structures, the invention patent with application number CN201920519796.X proposes a ring frame rigid structure, which is mainly made of metal or hard material, has the characteristics of high rigidity, but low elastic deformation capacity, and is difficult to absorb energy by deformation under low-speed impact, and the impact load will be directly transmitted to the internal components of the duct, causing the motor, blades and other components to be easily damaged by rigid collision, and the buffer protection function is poor; the invention patent with application number CN202411662411.7 proposes a duct fan structure beneficial to reducing noise, the duct cover is integrally formed after being coated with carbon fiber composite material, which ensures the structural strength, but the carbon fiber composite material has high rigidity, which is not conducive to the deformation and energy absorption of the duct cover, and too much energy is transmitted to the inner wall of the duct, which may cause the inner wall of the duct to deform; the invention patent with application number CN201610872892.3 proposes an electric duct rotor unmanned aerial vehicle, which proposes to set the carbon fiber plate on the outer wall of the duct body, which is also not conducive to the deformation and buffering of the duct; the invention patent with application number CN202221152134.1 provides a duct support arm and duct linkage structure, which can offset the deformation of the duct body due to the displacement of the aerodynamic force, but the support arm is large, which may increase the weight and resistance; the invention patent with application number CN201811513185.0 proposes an adjustable duct system with ultra-high stiffness-to-mass ratio, which arranges adjustable grid form stay wires in the duct, and the stiffness-to-mass ratio of the duct is large, so that when the unmanned aerial vehicle is working normally, there is no safety hazard due to the deformation of the duct, but when the duct is slightly collided, the protection effect on the inner wall of the duct is poor.

[0004] Foam sandwich structure, although has the advantages of light weight, low cost, convenient processing, can absorb impact energy through its own compression deformation, but in the low speed impact scene, the foam is easy to appear local excessive compression or compression failure problem, the energy absorption efficiency decreases rapidly with the increase of impact energy, it is difficult to sustain the buffer; at the same time, the foam structure is easy to cause irreversible plastic deformation after being impacted, which cannot be reused, and is easy to cause local parts to concentrate stress and damage. The paper sandwich structure can gradually disperse the impact load by deformation, and the structural stiffness and anti-deformation ability are better than those of the foam, and can realize certain energy absorption effect by bending and folding under low speed impact; but the structure has the problem of too large gap, and the load transmission is discontinuous at the initial stage of impact due to the hollow structure, and the buffer response lags; the energy absorption path of the structure is single, and when the impact energy is large, the structure is easy to be damaged by fracture, cannot dissipate energy by progressive deformation, the total energy absorption is limited, and the overall stability of the structure is insufficient, and the structure is easy to be dislocated and deformed after being impacted. The present application aims at the use requirement of excellent buffer energy absorption performance and structural stability under low speed impact, and provides a buffer energy absorption duct fan shell structure. SUMMARY

[0005] The present application aims to solve the technical problems in the prior art and provide a buffer energy absorption duct fan shell structure.

[0006] To achieve the above-mentioned object, the technical scheme provided by the present application is as follows: a buffer energy absorption duct fan shell structure, comprising a duct main body, the duct main body comprising a duct inner wall and a duct outer wall, a support plate is arranged on the duct inner wall, a slide rail is arranged on the support plate, and the duct inner wall, the support plate and the slide rail are integrally formed; a plurality of energy absorption units are slidably arranged on the slide rail, each energy absorption unit comprises a paper folding structure and an elastic hinge, the elastic hinge and the paper folding structure are integrally formed, the paper folding structure is V-shaped, the elastic hinge is arranged on both sides of the lower end of the paper folding structure, and the elastic hinge is slidably arranged on the slide rail, the upper end of the paper folding structure is bonded to the inner side of the duct outer wall by using an epoxy resin structure adhesive film, the plurality of paper folding structures are made into shapes suitable for the duct main body by a molding method, and the paper folding structure is made of a fiber reinforced epoxy resin composite material or a glass fiber composite material or an engineering plastic.

[0007] Preferably, a distance L is left between the elastic hinge in each energy absorption unit and the adjacent elastic hinge in the next energy absorption unit, the distance L satisfies 0.2S≤L≤0.5S, S is the distance between the elastic hinges on both sides of each energy absorption unit, the angle between the inclined surface on both sides of the paper folding structure and the normal line of the support plate is α, and 30°≤α≤60°.

[0008] Preferably, the plurality of paper folding structures form an inner energy absorption filling layer between the support plate, sliding rail and the duct inner wall, the inner energy absorption filling layer is filled with TPU foam material; the plurality of paper folding structures and the inside of the duct outer wall form an outer energy absorption filling layer, the outer energy absorption filling layer is filled with PMI foam material, and the TPU foam material and the PMI foam material are formed by die molding or on-site foaming process.

[0009] Preferably, the duct outer wall is made of flexible material, and the flexible material is one of aramid fiber composite material, glass fiber composite material, ultra-high molecular weight polyethylene fiber reinforced composite material and hybrid fiber reinforced composite material.

[0010] Preferably, the duct inner wall is made of carbon fiber reinforced epoxy resin-based composite material or carbon fiber reinforced phenolic resin composite material.

[0011] Preferably, the connecting part of the support plate and the duct inner wall is thickened.

[0012] The present application has the following beneficial effects:

[0013] 1. In the present application, through the multi-layer structure of the paper folding structure, hinge, inner energy absorption layer and outer energy absorption layer, when the present application is subjected to load, the duct outer wall is deformed to absorb energy first; then the inner energy absorption unit, the inner energy absorption layer and the outer energy absorption layer further absorb energy to disperse the load; the duct inner wall provides support; wherein the paper folding structure provides rigid support and load dispersion, the elastic hinge coordinates the deformation of the paper folding structure, which is conducive to the deformation of the elastic hinge driving the paper folding structure, optimizes the load transmission path, solves the problem of discontinuous load transmission of the paper folding structure when impacted, and the inner energy absorption layer and the outer energy absorption layer are respectively filled with TPU foam material and PMI foam material to strengthen the energy absorption effect and maintain the stability of the structure.

[0014] 2. In the present application, the duct outer wall is made of flexible material, which utilizes the high flexibility and high strength of the flexible material to quickly deform and absorb energy when impacted, thereby improving the impact resistance of the duct main body; in the present application, the duct inner wall is made of carbon fiber reinforced epoxy resin-based composite material or carbon fiber reinforced phenolic resin composite material, which relies on the advantages of high modulus and low density of the material to ensure the aerodynamic stability of the aircraft and the endurance of the unmanned aerial vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0015] The drawings described herein are used to provide further understanding of the present application, and form a part of the present application. The schematic embodiments of the present application and the description thereof are used to explain the present application, and do not constitute an improper limitation on the present application.

[0016] Figure 1 is a schematic diagram of the overall structure of the present application;

[0017] Figure 2It is the main body structure schematic diagram of the invention;

[0018] Figure 3 It is the enlarged structure schematic diagram of A in the invention;

[0019] Figure 4 It is the three view of the overall structure of the invention;

[0020] Figure 5 It is the enlarged structure schematic diagram of B in the invention;

[0021] Figure 6 It is the connection schematic diagram of paper structure, elastic hinge, slide rail and support plate in the invention;

[0022] Figure 7 It is the connection schematic diagram of elastic hinge and slide rail in the invention.

[0023] The figure mark is:

[0024] 1-folding paper structure, 2-elastic hinge, 3-slide rail, 4-support plate, 5-duct outer wall, 6-duct inner wall, 7-inner energy absorbing layer, 8-outer energy absorbing layer. Specific implementation

[0025] This part will describe the specific embodiments of the invention in detail, the preferred embodiments of the invention are shown in the drawings, the role of the drawings is to supplement the description of the text part with graphics, so that people can intuitively and visually understand each technical feature and the overall technical solution of the invention, but it cannot be understood as a limitation on the protection scope of the invention.

[0026] In the description of the invention, it should be understood that the orientation description, such as up, down, front, back, left, right, etc. The orientation or positional relationship shown in the drawing is based on the orientation or positional relationship shown in the drawing, only for the convenience of describing the invention and simplifying the description, and is not intended to indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, therefore it cannot be understood as a limitation on the invention.

[0027] In the description of the invention, several meanings are one or more, and multiple meanings are more than two, greater than, less than, more than, etc. Understand as not including the number, above, below, within, etc. Understand as including the number. If there is a description of the first, second, only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the sequence of indicated technical features.

[0028] In the description of the invention, unless otherwise explicitly limited, the words such as setting, installing, connecting, etc. Should be understood broadly, and the person skilled in the art can reasonably determine the specific meaning of the above words in the invention in combination with the specific content of the technical solution.

[0029] Referring to Figures 1-7 , the preferred embodiment of the present application, a buffer energy absorption duct fan shell structure, comprising a duct body, the duct body comprising a duct inner wall 6 and a duct outer wall 5, the duct inner wall 6 is provided with a support plate 4, the support plate 4 is provided with a slide rail 3, the duct inner wall 6, the support plate 4 and the slide rail 3 are integrally formed by the process; a plurality of energy absorption units are slidably arranged on the slide rail 3, each energy absorption unit comprises a paper folding structure 1 and an elastic hinge 2, the elastic hinge 2 and the paper folding structure 1 are integrally formed, the paper folding structure 1 is V-shaped, the elastic hinge 2 is arranged on both sides of the lower end of the paper folding structure 1, and the elastic hinge 2 is slidably arranged on the slide rail 3 (preferably, a sliding groove is formed on the elastic hinge 2 and slidably connected with the slide rail 3, as shown in Figure 7 ), when the duct body is subjected to low-speed impact, the movement of the elastic hinge 2 on the slide rail 3 under the impact load further drives the deformation of the paper folding structure 1, improves the energy absorption efficiency, and avoids the situation that the paper folding structure 1 is difficult to compress and deform or rubs with the duct inner wall 6 to hinder the structural deformation and energy absorption;

[0030] Further, the upper end of the paper folding structure 1 is bonded to the inner side of the duct outer wall 5 by an epoxy resin structure adhesive film, a plurality of paper folding structures 1 are made by a molding method to adapt to the shape of the duct body, which can better adapt to the circular wall surface of the duct body, realize uniform load transmission along the ring, and avoid stress concentration; the paper folding structure 1 is made of fiber reinforced epoxy resin composite material or glass fiber composite material or engineering plastic, so as to meet the support stiffness and deformation energy absorption requirements.

[0031] Further, an inner energy absorption filling layer 7 is formed between the plurality of paper folding structures 1 and the support plate 4, the slide rail 3 and the duct inner wall 6, the inner energy absorption filling layer 7 is filled with TPU foam material; the TPU foam material absorbs impact energy by compression deformation cooperated with the paper folding structure 1, the elastic hinge 2 and the slide rail 3, and fills the structural gap to improve the overall stability; an outer energy absorption filling layer 8 is formed between the plurality of paper folding structures 1 and the inner side of the duct outer wall 5, the outer energy absorption filling layer 8 is filled with PMI foam material, which ensures that the duct outer wall 5 can bear the aerodynamic load during work; the TPU foam material and the PMI foam material are molded or foamed on site to ensure close fit with each part.

[0032] It needs to be further explained that the paper folding structure 1 has the ability to return to the initial structure state after the collision (the TPU foam material and the PMI foam material have elasticity, will rebound under the extrusion of the two paper folding structures 1, and the material of the paper folding structure 1 itself has the characteristics of deformation energy absorption, realizing the recovery of the paper folding structure 1).

[0033] Specifically, when the duct suffers a low-speed impact, the impact load acts on the TPU foam material filled in the inner energy-absorbing filling layer 7 and the origami structure 1, the TPU foam material is compressed and deformed to absorb part of the energy, the origami structure 1 is expanded to both sides, and the origami structure 1 is further deformed by bending, stretching and other deformations to disperse energy and unload the load; the elastic hinge 2 deforms with the origami structure 1 and slides to both ends on the slide rail 3 to coordinate the movement of the origami structure 1, avoid local stress concentration, and continuously buffer and unload the force.

[0034] The present application gradually converts the impact kinetic energy into the foam compression energy, the origami structure 1 deformation energy and the energy absorbed by other components through the above three ways, realizes high-efficiency energy absorption and buffering, and protects the internal components.

[0035] In the embodiment, a spacing L is left between the elastic hinge 2 in a single energy-absorbing unit and the adjacent elastic hinge 2 in the next energy-absorbing unit, the spacing L satisfies 0.2S≤L≤0.5S, S is the distance between the elastic hinges 2 on both sides in a single energy-absorbing unit, and the angle between the slope on both sides of the origami structure 1 and the normal of the support plate 4 is α, 30°≤α≤60°.

[0036] Further, the duct outer wall 5 is made of a flexible material, the flexible material is one of aramid fiber composite material, glass fiber composite material, ultra-high molecular weight polyethylene fiber reinforced composite material and hybrid fiber reinforced composite material, the high flexibility, high specific strength and low density characteristics of the flexible material are used to absorb energy by deformation when impacted, and the impact load is avoided from being directly transmitted to the inside of the duct main body.

[0037] Further, the duct inner wall 6 is made of carbon fiber reinforced epoxy resin-based composite material or carbon fiber reinforced phenolic resin composite material, relies on the high modulus, high stiffness and low density advantages to maintain the structural stability under high-speed airflow, reduces the weight of the unmanned aerial vehicle and improves the endurance.

[0038] In the embodiment, the connection between the support plate 4 and the duct inner wall 6 is thickened to avoid stress concentration from causing structural damage.

[0039] In the use process of the present application, when the duct outer wall 5 is impacted, the impact load is conducted to the origami structure 1 through the duct outer wall 5 made of a flexible material and the PMI foam material filled in the inner energy-absorbing filling layer 7 and the outer energy-absorbing filling layer 8, the origami structure 1 is driven to deform, the deformation of the origami structure 1 deforms along the slide rail 3 through the integrally formed elastic hinge 2 to improve the deformation efficiency of the origami structure 1, thereby absorbing the impact energy, and at the same time, the deformation of the origami structure 1 can cause the load to impact the TPU foam material filled in the inner energy-absorbing filling layer to deform the internal TPU foam material to absorb the impact energy, thereby realizing multi-stage high-efficiency impact energy absorption.

[0040] The multi-layer structure of the origami structure 1, the elastic hinge 2, the inner energy absorption layer 7 and the outer energy absorption layer 8 is arranged in the application, so that when the application is subjected to a load, the outer wall 6 of the duct first deforms to absorb energy; then the inner energy absorption layer 7 and the outer energy absorption layer 8 further absorb energy to disperse the load; the inner wall 5 of the duct provides support; wherein the origami structure 1 provides rigid support and load dispersion, the elastic hinge 2 coordinates the deformation of the origami structure 1, which is conducive to the elastic hinge 2 driving the origami structure 1 to deform, optimizes the load transmission path, and solves the problem of discontinuous load transmission of the origami structure 1 when impacted; the inner energy absorption layer 7 and the outer energy absorption layer 8 are respectively filled with TPU foam material and PMI foam material to strengthen the energy absorption effect and maintain the stability of the structure.

[0041] In the application, the outer wall 5 of the duct is made of flexible material, which utilizes the dual characteristics of high flexibility and high strength of the flexible material to quickly deform and absorb energy when impacted, thereby improving the impact resistance of the duct body; in the application, the inner wall 6 of the duct is made of carbon fiber reinforced epoxy resin-based composite material or carbon fiber reinforced phenolic resin composite material, which relies on the advantages of high modulus and low density of the material to ensure the aerodynamic stability of the aircraft and the endurance capability of the unmanned aerial vehicle.

[0042] The above is only a preferred embodiment of the application, and any technical solution that achieves the same purpose by the same means, such as replacing the elastic hinge with a damping hinge, replacing the foam material with a polyethylene foam, an energy-absorbing spring or other elastic energy-absorbing structure or material, etc., all belong to the protection scope of the application.

Claims

1. A buffer-type energy-absorbing ducted fan housing structure, characterized in that: The culvert body includes an inner wall (6) and an outer wall (5). A support plate (4) is provided on the inner wall (6), and a slide rail (3) is provided on the support plate (4). The inner wall (6), support plate (4), and slide rail (3) are integrally formed. Multiple energy-absorbing units are slidably arranged on the slide rail (3). Each energy-absorbing unit includes an origami structure (1) and an elastic hinge (2). The elastic hinge (2) and origami structure (1) are integrally formed. The origami structure (1) is V-shaped. The elastic hinge (2) is set on both sides of the lower end of the origami structure (1), and the elastic hinge (2) is slidably arranged on the slide rail (3). The upper end of the origami structure (1) is bonded to the inner side of the outer wall (5) of the culvert using an epoxy resin structural film. Multiple origami structures (1) are molded to fit the shape of the culvert body by molding. The origami structure (1) is made of fiber-reinforced epoxy resin composite material, glass fiber composite material, or engineering plastic.

2. The buffer energy-absorbing ducted fan housing structure according to claim 1, characterized in that: There is a gap L between the elastic hinge (2) in a single energy-absorbing unit and the adjacent elastic hinge (2) in the next energy-absorbing unit. The gap L satisfies 0.2S≤L≤0.5S, where S is the distance between the elastic hinges (2) on both sides in a single energy-absorbing unit. The angle between the inclined planes on both sides of the origami structure (1) and the normal angle of the support plate (4) is α, where 30°≤α≤60°.

3. The buffer energy-absorbing ducted fan housing structure according to claim 1, characterized in that: An inner energy-absorbing filling layer (7) is formed between multiple origami structures (1), a support plate (4), a slide rail (3), and the inner wall of the culvert (6). The inner energy-absorbing filling layer (7) is filled with TPU foam material. An outer energy-absorbing filling layer (8) is formed between multiple origami structures (1) and between the inner side of the outer wall of the culvert (5). The outer energy-absorbing filling layer (8) is filled with PMI foam material. The TPU foam material and the PMI foam material are produced by compression molding or on-site foaming process.

4. The buffer energy-absorbing ducted fan housing structure according to claim 1, characterized in that: The outer wall of the culvert (5) is made of a flexible material, which is one of the following: aramid fiber composite material, glass fiber composite material, ultra-high molecular weight polyethylene fiber reinforced composite material, or hybrid fiber reinforced composite material.

5. The buffer energy-absorbing ducted fan housing structure according to claim 1, characterized in that: The inner wall of the culvert (6) is made of carbon fiber reinforced epoxy resin matrix composite or carbon fiber reinforced phenolic resin composite.

6. The buffer energy-absorbing ducted fan housing structure according to claim 1, characterized in that: The connection between the support plate (4) and the inner wall of the culvert (6) is thickened.

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