Unmanned aerial vehicle landing gear and door linkage retracting and extending mechanism

Abstract

The present invention relates to the technical field of aircraft landing gear, and specifically discloses a linkage retracting and extending mechanism of a landing gear and a door of a UAV, comprising a landing gear connected to a fuselage at one end, and a retracting and extending actuating assembly respectively hinged to the landing gear and the fuselage; the retracting and extending actuating assembly comprises a retracting and extending actuating cylinder and a connecting rod mechanism; the landing gear comprises an upper support fixedly connected to the fuselage at one end, and a lower support hinged to the other end of the upper support; the connecting rod mechanism is respectively hinged to the upper support and the lower support of the landing gear; the lower support is connected to the door through a rope; the door is hinged to the fuselage, and an elastic member is arranged between the door and the fuselage, and the elastic member is respectively hinged to the door and the fuselage. The lower support of the present invention is a part of the retracting and extending mechanism, and can effectively realize the retracting and extending of the lower support through the mutual cooperation of the rope, the elastic member, and the retracting and extending actuating assembly, and further realize the linkage retracting and extending of the landing gear door, thereby realizing the linkage retracting and extending function of the landing gear and the door in the narrow space of the nose.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft landing gear, and more particularly to a linkage retracting and extending mechanism of an unmanned aircraft landing gear and a cabin door. Background Art

[0002] An unmanned aerial vehicle has the dual capabilities of taking off and landing on water and taking off and landing on land airports, and can be adapted to more usage scenarios. When taking off and landing at a land airport, the landing gear needs to be kept completely lowered and locked on the ground to withstand the load of the aircraft during takeoff, landing, and ground taxiing; when flying in the air, the landing gear needs to be fully retracted and stored inside the fuselage, and the cabin door is closed to keep the aircraft's aerodynamic shape intact to reduce the aircraft's flight resistance and improve the aircraft's flight performance and fuel efficiency. When taking off and landing on water, the aircraft's landing gear uses its ship-shaped fuselage to taxi on the water to complete the take-off and landing operations, and the landing gear needs to be fully retracted and stored inside the fuselage, and its cabin door is closed to avoid adverse resistance and safety risks caused by exposed landing gear and open cabin door.

[0003] There are two common landing gear and door retraction technologies:

[0004] The first type is that the landing gear and the door each use a set of independent retracting and extending mechanisms and retracting and extending actuating components. The landing gear as a whole rotates around its main axis, and the sequential retracting and extending operations of the landing gear and the door are completed through multi-process sequential control. This landing gear retracting and extending method requires a large landing gear retracting and extending space, the length of the landing gear compartment is large, and the sequential control system is complex, the reliability is poor, and the structural weight cost is large;

[0005] The second type is to set a retraction and extension actuation assembly on the side diagonal strut of the landing gear, and the landing gear as a whole rotates around its main rotation axis, and then the landing gear and the cabin door are hingedly connected through a connecting rod mechanism, so that the cabin door is driven to close and open during the process of retraction and extension of the landing gear. This form of landing gear retraction and extension requires a large landing gear retraction and extension space, and the length of the landing gear compartment is large. In addition, the force transmission path of the linkage retraction and extension mechanism of the landing gear and the cabin door is long. The stiffness of the connecting rod mechanism and its body supporting structure directly affects whether the opening and closing state of the cabin door meets the design requirements, and even affects whether the linkage retraction and extension function of the landing gear and the cabin door can be successfully realized.

[0006] Judging from the current application examples in the field of unmanned aerial vehicle landing gear, the common problems of these two retracting and extending mechanisms are: first, the space size of the aircraft landing gear body, especially the nose, is small, while the storage compartment required for the landing gear is large, making the layout of the landing gear, especially the nose landing gear, very difficult; second, the force transmission path of the connecting rod mechanism is too long, and the lightweight design makes the rigidity of the connecting rod mechanism poor, resulting in the door being unable to open properly, and the gap with the fuselage structure is too large when closed, affecting the aerodynamic shape of the body. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a linkage retracting and extending mechanism for the landing gear and the cabin door of an unmanned aerial vehicle. The landing gear strut is designed as a structure that can be separated up and down, and the lower strut is a part of the retracting and extending mechanism. Through the mutual cooperation of ropes, elastic parts, and retracting and extending actuating components, the retraction and extension of the lower strut part of the landing gear can be effectively realized, and the linkage retraction and extension of the landing gear cabin door can be further realized, thereby realizing the linkage retracting and extending function of the landing gear and the cabin door in the narrow space of the nose.

[0008] The solution adopted by the present invention to solve the technical problem is:

[0009] A linkage retracting and extending mechanism for a landing gear and a door of an unmanned aerial vehicle comprises a landing gear connected to a fuselage at one end, and a retracting and extending actuating assembly respectively hinged to the landing gear and the fuselage; the landing gear comprises an upper support column fixedly connected to the fuselage at one end, and a lower support column hinged to the other end of the upper support column and serving as a retracting and extending mechanism; the retracting and extending actuating assembly is respectively hinged to the upper support column and the lower support column of the landing gear; the lower support column is connected to the door by a rope; the door is hinged to the fuselage, an elastic member is provided between the door and the fuselage, and the elastic member is respectively hinged to the door and the fuselage.

[0010] The present invention can effectively realize the retraction and extension of the lower support part of the landing gear through the mutual cooperation of the rope, the elastic member and the retraction and extension actuation assembly, and further realize the linkage retraction and extension of the landing gear door, thereby realizing the linkage retraction and extension function of the landing gear and the door in the narrow space of the nose.

[0011] Landing gear and door retraction process:

[0012] The landing gear is in a fully extended state. When receiving the command to retract the landing gear, the retracting and extending actuating assembly drives the lower strut hinged to it to rotate clockwise around the hinge point between the lower strut and the upper strut, so that the lower strut moves in a clockwise direction and retracts in the forward direction, and finally is completely retracted into the landing gear compartment at the nose of the aircraft;

[0013] When the lower strut of the landing gear is retracted in the forward direction, the rope connected to the lower strut will drive the door to rotate inward around the hinge point between it and the fuselage, compressing the elastic member and finally closing the door. After the landing gear and door are retracted, the piston rod of the retracting and extending actuator is locked, thus keeping the landing gear and door in the retracted state during flight.

[0014] On the contrary, the landing gear and door lowering process:

[0015] When the landing gear is lowered, the piston rod in the retracting and extending actuating assembly contracts, causing the lower strut hinged to the retracting and extending actuating assembly to rotate counterclockwise around its hinge point with the upper strut, and the lower strut moves in the counterclockwise direction. At this time, the rope changes from a taut state to a slack state. Under the thrust of the elastic member and the deadweight of the hatch, the aerodynamic resistance of the hatch is overcome, and the hatch rotates outward around its hinge point with the fuselage, and the hatch opens. When the upper strut and the lower strut of the landing gear are close to each other and fully fit on one side, the lower strut of the landing gear is completely lowered, and the hatch is fully opened.

[0016] In some possible implementations, in order to effectively realize the folding of the landing gear struts and reduce the demand for the stowage space;

[0017] The upper support comprises a support column connected to the fuselage and hinged to the retractable actuating assembly, and a retractable upper support member installed on the outside of the support column;

[0018] The lower support column comprises a fork connecting member, a wheel assembly installed on the fork connecting member, and a retractable lower support member hinged to the retractable upper support member and installed on the wheel assembly.

[0019] In some possible implementations, in order to ensure that the upper support and the lower support can effectively contact and align when the landing gear is lowered, to ensure that the direction is stable during taxiing, and to ensure that the load can be effectively transferred during use;

[0020] A V-shaped docking groove is arranged at one end of the support column away from the fuselage, and the lower support column also includes a V-shaped boss installed on the retractable support member and adapted to the V-shaped docking groove.

[0021] In some possible implementations, in order to effectively realize the articulation of the upper support and the lower support, and to enable the lower support to rotate around the articulation point under the drive of the retractable actuating assembly;

[0022] The retractable upper support member comprises two sets of L-shaped plates 1 which are symmetrically arranged and clamped on the outside of the support column by bolts;

[0023] The retractable and lowerable support member comprises two groups of L-shaped plates 2 which are symmetrically arranged and clamped on the fork connecting member by bolts.

[0024] In some possible implementations,

[0025] The supporting column comprises a column body, an upper V-shaped docking cam which is installed at one end of the column body away from the fuselage and has a V-shaped docking groove at the bottom.

[0026] In some possible implementations, in order to effectively fix the upper V-shaped docking cam;

[0027] A threaded hole is provided at one end of the support column away from the fuselage, and the top of the upper V-shaped docking cam is installed in the threaded hole;

[0028] A pin hole is also provided on the support column, and the pin hole is communicated with the threaded hole;

[0029] An upper connecting piece is sleeved on the outer side of the supporting column, and a coaxial large hole and a small hole are arranged on the upper connecting piece, wherein the diameter of the small hole is smaller than the diameter of the pin; when the supporting column is fixedly connected to the upper connecting piece, the axes of the large hole, the small hole and the pin hole are colinear.

[0030] In some possible implementations, in order to effectively realize the retractable actuating assembly driving the lower strut to rotate around the hinge point between the lower strut and the upper strut, the upper strut and the lower strut are folded, thereby realizing the retractable and retractable landing gear;

[0031] The retractable actuating assembly comprises a retractable actuating cylinder with one end hinged to the fuselage, and a connecting rod mechanism arranged at the other end of the retractable actuating cylinder and hinged to the upper support and the lower support respectively.

[0032] In some possible implementations,

[0033] The connecting rod mechanism comprises an upper connecting rod with one end hinged to the upper support, a lower connecting rod with one end hinged to the lower support and the other end hinged to the upper connecting rod, and the upper connecting rod is hinged to the end of the retractable actuator away from the fuselage.

[0034] In some possible implementations, in order to effectively open or close the hatch;

[0035] A joint is arranged on the door, and the door is hinged to a rotating shaft arranged on the fuselage through the joint; the elastic member is a gas spring, and two ends of the gas spring are respectively hinged to the fuselage and the joint.

[0036] In some possible implementations, in order to effectively close the hatch through the cooperation between the lower support and the elastic member;

[0037] The wheel assembly comprises a fork assembly connected to a fork connector and a wheel mounted on the fork assembly; one end of the rope is connected to the fork assembly.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] In the present invention, the landing gear strut is designed to be an upper strut and a lower strut which are separable from each other, thus changing the structure of the traditional landing gear. The upper strut and the lower strut are respectively hingedly connected through a retracting and extending actuating assembly, and the lower strut is driven to rotate around the hinge point between the upper strut and the lower strut through the retracting and extending actuating assembly, mainly to realize the retraction and extension of the lower strut. The retracting and extending actuating assembly formed by the retracting and extending actuating cylinder and the four-bar linkage has a compact structure, thereby reducing the space required for the retracting and extending of the landing gear and greatly reducing the length of the nose landing gear compartment. A single linear retracting and extending actuating assembly is used as a power source, which has high safety and reliability.

[0040] Compared with the prior art of retracting and extending the entire landing gear strut with a larger length, the four-bar linkage formed in the present invention has a short connecting rod length and a light weight, and can significantly reduce the landing gear's requirement for the length of the storage compartment, which helps to achieve the linked retraction and extension of the landing gear and the cabin door in the narrow space of the nose.

[0041] The lower support and the upper support of the present invention cooperate with the upper V-shaped docking cam and the V-shaped boss to realize the wheel return when the landing gear is lowered, ensure that the front wheel direction is in a neutral position when the UAV lands, and ensure the directional stability of the UAV when gliding on the ground; at the same time, the upper V-shaped docking cam and the V-shaped boss work together with the connecting rod retraction and extension mechanism and the retraction and extension actuator to realize the transmission of ground load.

[0042] The present invention realizes the linkage retracting and extending function of the landing gear and its door through the iron chain and the gas spring; when the landing gear is retracted, the tension is transmitted through the iron chain to drive the door to close, the iron chain has large tensile stiffness, the force transmission method is direct and the path is short, which can effectively ensure that the door is tightly closed, the fuselage shape is intact, and the resistance of flying in the air and gliding on the water is reduced; when the landing gear is lowered, the door is automatically opened by the thrust of the gas spring, reducing the load on the retracting and extending actuator.

[0043] The present invention can effectively enable the landing gear door to be retracted and extended through a single retracting and extending actuator, requires less resources for the retracting and extending system, reduces system complexity, simplifies control logic, and improves the reliability of retracting and extending the landing gear. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the structural relationship of the present invention;

[0045] Figure 2 It is a schematic diagram of the structure of the upper support in the present invention;

[0046] Figure 3 is a cross-sectional view of the upper support in the present invention;

[0047] Figure 4 It is a structural schematic diagram of the upper pillar, the retractable upper support member, the upper connecting member and the upper V-shaped docking cam in the present invention when they are assembled;

[0048] Figure 5 It is a structural schematic diagram of the upper pillar, the retractable upper support member, the upper connecting member and the upper V-shaped docking cam in the present invention after being assembled;

[0049] Figure 6 It is a schematic diagram of the structure of the retractable support member, the V-shaped boss, the fork assembly, and the wheel in the present invention;

[0050] Figure 7 It is a schematic diagram of the connection relationship between the retractable and lowered support member, the retractable and lowered upper support member, and the retractable and lowered actuating assembly when the landing gear is lowered in the present invention;

[0051] Figure 8 It is a schematic diagram of the connection relationship between the retractable and lower support member, the retractable and upper support member, and the retractable and actuating assembly during the retracting process of the landing gear in the present invention;

[0052] Fig. 9 It is a schematic diagram of the connection relationship between the retractable and lower supporting member, the retractable and upper supporting member, and the retractable and actuating assembly after the landing gear is retracted in the present invention;

[0053] Fig.10 It is a schematic diagram of the structure of the door, landing gear, rope and elastic member after the landing gear is lowered in the present invention;

[0054] Fig.11 It is a structural schematic diagram of the hatch, the landing gear and the fuselage after the landing gear is stored in the landing gear compartment in the present invention;

[0055] Fig.12 It is a structural schematic diagram of the landing gear and fuselage after the landing gear is lowered in the present invention;

[0056] Among them: 1-upper pillar, 11-supporting column, 12-retractable upper support member, 13-upper V-shaped docking cam, 14-upper connecting member, 141-small hole, 142-large hole, 15-pin, 2-lower pillar, 21-retractable and lower support member, 22-V-shaped boss, 23-wheel fork assembly, 24-lower connecting member, 25-wheel, 26-wheel fork connecting member, 3-rope, 4-elastic member, 10-retractable actuator assembly, 100-retractable actuator cylinder, 101-upper connecting rod, 102-lower connecting rod, 103-connecting shaft, 20-cabin door. DETAILED DESCRIPTION

[0057] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. The "first", "second" and similar words mentioned in this application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, "one" or "one" and other similar words do not indicate a quantity restriction, but indicate the existence of at least one. In the implementation of this application, "and / or" describes the association relationship of the associated objects, indicating that there can be three relationships, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In the description of the embodiments of the present application, unless otherwise specified, the meaning of "multiple" refers to two or more. For example, multiple positioning columns refer to two or more positioning columns. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] The present invention is described in detail below.

[0059] like Figure 1-Figure 12 As shown:

[0060] A linkage retracting and extending mechanism for landing gear and door 20 of an unmanned aerial vehicle, used to realize linkage retracting and extending of the landing gear and door 20; comprising a landing gear connected to a fuselage at one end, and a retracting and extending actuating assembly 10 respectively hinged to the landing gear and the fuselage;

[0061] The landing gear comprises an upper support 1 with one end fixedly connected to the fuselage, and a lower support 2 hinged to the other end of the upper support 1; the retractable actuating assembly 10 is hinged to the upper support 1 and the lower support 2 respectively;

[0062] The upper support 1 is arranged vertically and fixedly connected to the fuselage; the upper support 1 is always kept in a vertical state during the landing gear retraction and extension process; the upper support 1 is not retracted;

[0063] The lower support 2 is connected to the hatch 20 via a rope 3;

[0064] The door 20 is hinged to the fuselage, and an elastic member 4 is provided between the door 20 and the fuselage. The elastic member 4 is hinged to the door 20 and the fuselage respectively.

[0065] Working principle:

[0066] The process of retracting the landing gear and the door 20: In the initial state, the landing gear is in a fully lowered state. When receiving the command to retract the landing gear, the retracting and extending actuator assembly 10 controls the lower support 2 hinged thereto to rotate clockwise around the hinge point between the lower support 2 and the upper support 1, so that the lower support 2 moves in the clockwise direction and retracts in the forward direction, and finally is completely retracted into the landing gear compartment at the nose. During the process of retracting the lower support 2 of the landing gear in the forward direction, the rope 3 connected to the lower support 2 will drive the door 20 to rotate inward around the hinge point between the lower support 2 and the fuselage, and at the same time compress the elastic member 4, and finally close the door 20; after the landing gear and the door 20 are retracted into place, the piston rod of the retracting and extending actuator assembly 10 is locked, so as to keep the landing gear and the door 20 always retracted during flight, and the rope 3 will be in a tensioned state at this time.

[0067] The process of lowering the landing gear and the door 20: in the initial state, the landing gear is retracted in the landing gear retracting compartment of the fuselage; when lowering the landing gear, the retracting actuator assembly 10 drives the lower support 2 hinged thereto to rotate counterclockwise around the hinge point between the lower support 2 and the upper support 1, and the lower support 2 will move in the counterclockwise direction. At this time, the rope 3 will change from a tightened state to a relaxed state. Under the thrust of the elastic member 4 and the deadweight of the door 20, the aerodynamic resistance of the door 20 is overcome, and the door 20 will rotate outward around the hinge point between the door 20 and the fuselage, and the door 20 will open. When the upper support 1 and the lower support 2 of the landing gear are close to each other and completely fit on one side, the lower support 2 of the landing gear is completely lowered, and the door 20 is completely opened;

[0068] Compared with the prior art, the present invention effectively realizes the retraction and extension of the landing gear column part through the cooperation of a set of retracting and extending actuating components 10 with ropes 3 and elastic members 4, and at the same time drives the hatch door 20 to realize opening and closing in linkage. Since the present invention only retracts and extends a part of the landing gear column (the lower support column 2), the retracting and extending space requirement for the landing gear is small, and the height and length of the nose landing gear retracting and extending compartment are greatly reduced; and a single linear retracting and extending actuating component 10 is used as a power source, which has high safety and reliability.

[0069] Preferably, the rope 3 is an iron chain, a steel cable, etc., and the elastic member 4 is a compression spring or a gas spring.

[0070] In some possible implementations, in order to effectively realize the retraction and extension of the landing gear lower strut 2, the demand for the retraction and extension space is reduced;

[0071] The upper support 1 comprises a support column 11 connected to the fuselage and hinged to the retractable actuating assembly 10, and a retractable upper support member 12 installed on the outside of the support column 11;

[0072] The lower support 2 includes a fork connector 26 , a wheel assembly mounted on the fork connector 26 , and a retractable support 21 hinged to the retractable upper support 12 and mounted on the wheel assembly; the wheel assembly is located below the retractable upper support 12 .

[0073] The support column 11 and the lower column 2 are hingedly connected by the retractable upper support member 12 and the retractable lower support member 21 to realize the hinged connection between the upper column 1 and the lower column 2; since the retractable actuating assembly 10 is hingedly connected to the upper column 1 and the lower column 2 respectively, the retractable action assembly can effectively control the lower column 2 to rotate around the hinge point between the retractable lower support member 21 and the retractable upper support member 12; thereby realizing the change of the angle between the lower column 2 and the upper column 1, and realizing the retraction and extension of the lower column of the landing gear; compared with the prior art in which the entire landing gear column with a larger length is rotated around the rotation axis between it and the fuselage to realize the retraction and extension of the landing gear, the present invention only retracts and extends a part of the landing gear column (the lower column 2), which makes the demand for retraction and extension space smaller during the retraction and extension process.

[0074] In some possible implementations, in order to ensure that when the landing gear is lowered, the upper support 1 and the lower support 2 can be effectively docked and the aircraft is in rotation, to ensure the stability of the flight direction during taxiing, and to ensure that the load can be effectively transferred during use;

[0075] The support column 11 is provided with a V-shaped docking groove at one end away from the fuselage, and the lower support column 2 further includes a V-shaped boss 22 installed on the retractable support member 21 and adapted to the V-shaped docking groove.

[0076] When the landing gear is lowered, the lower support 2 rotates counterclockwise around the hinge point with the upper support 1, driving the V-shaped boss 22 to rotate into the V-shaped docking groove; when the support column 11 and the lower support 2 are coaxial, the top of the V-shaped boss 22 will be mortise and tenoned in the V-shaped docking groove; this will effectively ensure that the support column 11 and the lower support 2 can be effectively aligned, and at the same time, the V-shaped surface is used to abut, so that the contact surface is larger, which can effectively transfer the vertical load, heading load and lateral load acting on the lower support 2 by the ground to the fuselage structure, and can also effectively ensure the directional stability during landing and ground movement.

[0077] In some possible implementations, in order to effectively realize the articulation of the upper support 1 and the lower support 2, and to enable the lower support 2 to rotate around the articulation point under the drive of the retractable actuating assembly 10;

[0078] The retractable upper support member 12 comprises two sets of L-shaped plates 1 which are symmetrically arranged and clamped on the outside of the support column 11 by bolts;

[0079] The retractable and lowerable support member 21 includes two groups of L-shaped plates 2 that are symmetrically arranged and clamped on the fork connecting member 26 by bolts.

[0080] In some possible implementations, in order to avoid serious wear of the V-shaped butt joint groove and the V-shaped boss 22 after long-term use, resulting in failure to properly center the support column 11 and the lower support column 2;

[0081] The support column 11 includes a column body arranged vertically and connected to the fuselage at one end, an upper V-shaped docking cam 13 installed at the end of the column body away from the fuselage and having a V-shaped docking groove at the bottom. .

[0082] The V-shaped boss 22 is fixed to the fork connector 26 by two positioning pins and a fastening bolt, and its V-shaped surface cooperates with the V-shaped docking groove of the upper V-shaped docking cam 13;

[0083] A V-shaped docking cam 13 is installed at the end of the support column 11 away from the fuselage, and a V-shaped docking groove is provided at the bottom thereof, and the top of the V-shaped boss 22 is adapted to the V-shaped docking groove; in this way, it can be replaced after long-term use, avoiding the situation where it cannot be used normally due to severe wear;

[0084] In some possible implementations, in order to effectively fix the upper V-shaped docking cam 13,

[0085] The support column 11 is provided with a threaded hole at one end away from the fuselage, and the top of the upper V-shaped docking cam 13 is installed in the threaded hole; the threaded hole is coaxially arranged with the support column 11; the top of the upper V-shaped docking cam 13 is provided with a threaded boss adapted to the threaded hole;

[0086] A pin hole is also provided on the support column 11, and the pin hole is connected to the threaded hole; the axis of the pin hole and the axis of the threaded hole are perpendicular to each other, and a through hole connected to the pin hole is provided on the threaded boss;

[0087] When installing the upper V-shaped docking cam 13, firstly, the threaded boss is screwed to the threaded hole, and the through hole is connected to the pin hole, and then one end of the pin 15 is passed through the pin hole and the through hole in sequence, so as to fix the upper V-shaped docking cam 13;

[0088] Preferably, the pin holes are in two groups and are coaxially arranged;

[0089] An upper connecting piece 14 is mounted on the outer side of the supporting column 11, and a coaxial large hole 142 and a small hole 141 are provided on the upper connecting piece 14, wherein the diameter of the small hole 141 is smaller than the diameter of the pin 15; when the supporting column 11 is fixedly connected to the upper connecting piece 14, the large hole 142, the small hole 141 and the axis of the pin hole are colinear.

[0090] like Figure 4 , Figure 5As shown, when the upper V-shaped docking cam 13 is installed, one end of the pin 15 passes through the large hole 142, the pin hole, the through hole in sequence, and then enters another pin hole; after assembly, the upper connecting member 14 is rotated so that the small hole 141 rotates 180° to the original position of the large hole 142, and the upper connecting member 14 is fixed, so that the pin 15 will not be able to withdraw from the pin hole; the reliability of the threaded connection between the upper V-shaped docking cam 13 and the supporting column 11 is ensured.

[0091] An annular chamber will be formed between the upper V-shaped docking cam 13 and the bottom of the retractable upper support member 12, and the upper connecting member 14 will be sleeved on the outer side of the supporting column 11 and located in the annular chamber.

[0092] In some possible implementations, in order to effectively realize the retractable actuation assembly 10 drives the lower support 2 to rotate around the hinge point between the upper support 1 and the lower support 2, thereby realizing the folding of the upper support 1 and the lower support 2, and then realizing the retractable landing gear;

[0093] The retractable actuator assembly 10 includes a retractable actuator cylinder 100 with one end hinged to the fuselage, and a connecting rod mechanism arranged at the other end of the retractable actuator cylinder 100 and hinged to the upper support 1 and the lower support 2 respectively.

[0094] The retractable actuator 100 adopts existing equipment, including a cylinder body and a piston rod connected to the cylinder body; its specific internal structure is not described in detail here;

[0095] like Figure 7-Figure 9 As shown, when the lowered landing gear needs to be retracted into the retractable compartment, the piston rod extends, driving the connecting rod mechanism to drive the lower support 2 to rotate in the clockwise direction around the hinge point of the retractable upper support member 12 and the retractable support member 21, and retract in the forward direction to achieve the retraction of the lower support 2. During the rotation of the lower support 2, it will drive the compartment to rotate inward, and finally be completely retracted into the nose landing gear compartment and the compartment door 20 will be closed at the same time;

[0096] In some possible implementations, in order to effectively realize the driving of the lower support 2 by the connecting assembly under the driving of the retracting and extending actuator 100, and then realize the lowering or retracting of the landing gear lower support 2 and the linkage of the door 20, so as to realize the opening and closing of the door;

[0097] The connecting rod mechanism includes an upper connecting rod 101 with one end hinged to the upper connecting piece 14 in the upper support 1, and a lower connecting rod 102 with one end hinged to the lower support 2 and the other end hinged to the upper connecting rod 101. The upper connecting rod 101 is hinged to the end of the retractable actuator 100 away from the fuselage.

[0098] like Figure 7-Figure 9As shown, the upper connecting rod 101, the lower connecting rod 102, the retractable upper support member 12, and the retractable lower support member 21 form a four-bar linkage; the upper connecting rod 101 is provided with a connecting shaft 103 hinged to the piston rod of the retractable actuator 100; the connecting shaft 103 is located between the hinge point between the upper connecting rod 101 and the upper connecting member 14 and the hinge point between the upper connecting rod 101 and the lower connecting rod 102, and is close to the hinge point between the upper connecting rod 101 and the lower connecting rod 102; the four-bar linkage is driven to move by the extension or shortening of the piston rod of the retractable actuator 100, thereby driving the lower strut 2 of the landing gear and the door 20 to complete the retracting or extending operation.

[0099] When the landing gear is in the lowered state, the piston rod of the retracting actuator 100 is in a locked state, and the upper strut 1 and the lower strut 2 of the landing gear are docked through the engagement of the upper V-shaped docking cam 13 and the V-shaped boss 22, so that the landing gear wheel 25 returns to the center and is held, ensuring the directional stability of the UAV during landing and ground movement, and at the same time transmitting the vertical load, heading load and lateral load acting on the wheel 25 by the ground to the fuselage structure.

[0100] In the present invention, since only the lower column 2 of the landing gear is retracted and extended, the length of each connecting rod in the formed connecting rod mechanism is short and light, thereby significantly reducing the landing gear's requirement for the length of the storage compartment, which helps to achieve the linked retraction and extension of the landing gear and the cabin door 20 in the narrow space of the nose.

[0101] In some possible implementations, in order to effectively realize the opening or closing of the hatch 20 under the drive of the elastic member 4, the retractable actuating assembly, and the lower column 2;

[0102] The door 20 is provided with a joint, and the door 20 is hinged to a rotating shaft provided on the fuselage through the joint; the elastic member 4 is a gas spring, and two ends of the gas spring are respectively hinged to the fuselage and the joint.

[0103] One end of the joint is mounted on the door 20, and the other end is hinged to the fuselage through a rotating shaft, and the gas spring is connected to the joint; when the lower column 2 of the landing gear is lowered, the gas spring will provide thrust to the door 20;

[0104] The lower support 2 is connected to the door 20 by an iron chain; when the landing gear is lowered, the piston rod contracts, the lower support 2 will rotate counterclockwise along the hinge point, and the iron chain will change from the original tightened state to a relaxed state. At this time, the gas spring will apply a thrust to the door 20. Under the action of the thrust and the deadweight of the door 20, the aerodynamic resistance of the door 20 is overcome, and the left and right doors 20 rotate outward around the rotation axis of the door 20, and the door 20 opens. When the upper V-shaped docking cam 13 of the upper support 1 of the landing gear is docked with the V-shaped boss 22 in the lower support 2, the lower support 2 of the landing gear is completely lowered, the door 20 is completely opened, and the landing gear is lowered.

[0105] In some possible implementations, in order to effectively close the hatch 20 through the cooperation between the lower support 2 and the elastic member 4;

[0106] The wheel assembly includes a fork assembly 23 connected to a fork connector 26 and a wheel 25 mounted on the fork assembly 23 ; one end of the rope 3 is connected to the fork assembly 23 .

[0107] In the prior art, the cabin door 20 is composed of two leaves that are set apart from each other, and both are hinged to the fuselage through the cooperation of the joint and the rotating shaft; the fork assembly 23 is connected to the fork connector to form a U-shaped structure with the opening facing downward, and its two sides will be connected to the cabin door 20 through ropes 3 respectively, and the wheel 25 will be rotatably installed in the opening groove of the U-shaped structure.

[0108] In order to facilitate the installation of the V-shaped boss 22 , a lower connecting member 24 is provided on the retractable and lowerable support member 21 ; the retractable and lowerable support member 21 is hinged to the lower connecting rod 102 via the lower connecting member 24 , and the V-shaped boss 22 is installed on the lower connecting member 24 .

[0109] When the landing gear is retracted, since the rope 3 is connected to the hatch 20 and the fork assembly 23, the pulling force can be transmitted to drive the hatch 20 to move, thereby realizing the linkage retraction operation of the landing gear and the hatch 20; in order to make the hatch 20 in a completely closed state when the landing gear is retracted into place, the number of chain links and the direction of the rotating earring bolts can be appropriately adjusted to change the effective length of the chain; when the landing gear is lowered, the thrust of the gas spring and the gravity of the hatch 20 overcome the aerodynamic resistance of the hatch 20, and push the hatch 20 to open automatically with the landing gear.

[0110] Preferably, an earring bolt is provided on the fork assembly 23, and the rope 3 is connected to the fork assembly 23 via the earring bolt.

[0111] When there are two groups of doors 20, the elastic member 4 is divided into two groups, which are respectively connected to the joints connecting the two groups of doors 20. When the landing gear is lowered, thrust is effectively applied to the two groups of doors 20 so that the doors 20 are opened.

[0112] The present invention can be used for the linkage retraction and extension of the front landing gear and the cabin door, and can also be used for the linkage retraction and extension of the main landing gear and the cabin door;

[0113] Furthermore, a locking flange is mounted on the outer side of the end of the support column 11 close to the fuselage, and the locking flange is fixed by cooperating with the flange pin through the locking nut mounted on the inner side of the support column 11. The locking flange is fixedly connected to the fuselage through the locking flange, so that when it is used as the front landing gear, it can transmit the turning servo torque to control the front wheel to turn.

[0114] The present invention is not limited to the above-mentioned specific embodiments, but extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. A linkage retractable and extending mechanism for landing gear and door of an unmanned aerial vehicle, comprising a landing gear connected to a fuselage at one end, and a retractable and extending actuating assembly (10) respectively hinged to the landing gear and the fuselage; It is characterized in that The landing gear comprises an upper support (1) with one end fixedly connected to the fuselage, and a lower support (2) hingedly connected to the other end of the upper support (1); The retractable actuating assembly (10) is hinged to the upper support (1) and the lower support (2) respectively; the lower support (2) is connected to the cabin door (20) via a rope (3); An elastic member (4) is provided between the door (20) and the fuselage, and the elastic member (4) is hinged to the door (20) and the fuselage respectively; the upper support (1) comprises a support column (11) connected to the fuselage and hinged to the retractable actuating assembly (10), and a retractable upper support member (12) installed on the outside of the support column (11); The lower support column (2) comprises a wheel fork connecting member (26), a wheel assembly mounted on the wheel fork connecting member (26), and a retractable support member (21) hingedly connected to the retractable upper support member (12) and mounted on the wheel assembly; a V-shaped docking groove is provided at one end of the support column (11) away from the fuselage; The lower support (2) also includes a V-shaped boss (22) mounted on the fork connector (26) and adapted to the V-shaped docking groove; the support column (11) includes a column body, an upper V-shaped docking cam (13) mounted on an end of the column body away from the fuselage and provided with a V-shaped docking groove; the retractable upper support (12) includes two groups of L-shaped plates symmetrically arranged and clamped on the outside of the support column (11) by bolts; The retractable and lowerable support member (21) comprises two groups of L-shaped plates 2 which are symmetrically arranged and clamped on the fork connecting member (26) by bolts.

2. The unmanned aerial vehicle landing gear and door linkage retracting and extending mechanism according to claim 1, It is characterized in that A threaded hole is provided at one end of the support column (11) away from the fuselage, and the top of the upper V-shaped docking cam (13) is installed in the threaded hole; A pin hole is also provided on the supporting column (11), and the pin hole is connected to the threaded hole; An upper connecting piece (14) is sleeved on the outer side of the supporting column (11), and the upper connecting piece (14) is provided with a coaxial large hole (142) and a small hole (141), wherein the diameter of the small hole (141) is smaller than the diameter of the pin (15); when the supporting column (11) and the upper connecting piece (14) are fixedly connected, the large hole (142), the small hole (141) and the axis of the pin hole are colinear.

3. A linkage retracting and extending mechanism for landing gear and door of an unmanned aerial vehicle according to any one of claims 1 to 2, It is characterized in that The retractable actuating assembly (10) comprises a retractable actuating cylinder (100) having one end hinged to the fuselage, and a connecting rod mechanism arranged at the other end of the retractable actuating cylinder (100) and respectively hinged to the upper support (1) and the lower support (2).

4. The unmanned aerial vehicle landing gear and door linkage retracting and extending mechanism according to claim 3, It is characterized in that The connecting rod mechanism comprises an upper connecting rod (101) having one end hinged to an upper support (1), a lower connecting rod (102) having one end hinged to a lower support (2) and the other end hinged to the upper connecting rod (101), and the upper connecting rod (101) is hinged to an end of a retractable actuator cylinder (100) away from the fuselage.

5. A linkage retracting and extending mechanism for landing gear and door of an unmanned aerial vehicle according to any one of claims 1 to 2, It is characterized in that A joint is provided on the cabin door (20), and the cabin door (20) is hinged to a rotating shaft provided on the fuselage via the joint. The elastic member (4) is a gas spring, and its two ends are respectively hinged to the fuselage and the joint.

6. The unmanned aerial vehicle landing gear and door linkage retracting and extending mechanism according to claim 1, It is characterized in that The wheel assembly comprises a fork assembly (23) connected to a fork connector (26), and a wheel (25) mounted on the fork assembly (23); one end of the rope (3) is connected to the fork assembly (23).

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