Landing gear drop device and method

Abstract

A landing gear drop device (100), comprising: a gantry (110); the connecting rod mechanism (120) is mounted on the rack (110), and each connecting rod in the connecting rod mechanism (120) can move relative to the rack (110); the undercarriage bracket (130) can be pivotally mounted on a corresponding connecting rod in the connecting rod mechanism (120), and the undercarriage bracket (130) is configured to be used for fixedly mounting a to-be-tested undercarriage (200) on the undercarriage bracket (130) so as to enable the to-be-tested undercarriage (200) to move along with the undercarriage bracket (130), the linkage mechanism (120) is configured such that the landing gear bracket (130) can move linearly with movement of the linkage mechanism (120). According to the falling device, clearance vibration and friction of the roller components are avoided, the energy and the landing posture when the undercarriage collides with the ground are guaranteed, and the falling precision is improved. The invention further relates to an undercarriage shock falling method using the shock falling device.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of mechanical design, specifically to the field of aircraft structure test, more specifically to an aircraft landing gear drop device for landing gear drop test and the like. BACKGROUND

[0002] Landing gear drop technology belongs to ground load verification technology, which plays a very key role in aircraft design. The purpose is to verify the landing dynamic characteristics of the landing gear, verify the correctness of the landing load simulation analysis model and the reserve energy absorption capacity of the buffer system.

[0003] At present, the landing gear drop adopts the vertical drop mode. When dropped, the landing gear basket together with the landing gear to be tested below slides downward along the motion guide mechanism on the drop test stand by means of rollers, such as the Chinese invention patent application publication CN101520364A and the Chinese utility model patent CN204495533.

[0004] The following further lists other patent documents in the field to show the state of the art.

[0005] CN101532903B of Nanjing University of Aeronautics and Astronautics relates to a drop test device of a movable impact platform, which can be used in the fields of landing gear drop rotation test, taxiway characteristic test, tire static characteristic test and tire dynamic characteristic test. It includes a gantry, a ground fixing mechanism, a retracting mechanism, a basket, a landing gear, a basket guide mechanism and a gap adjusting mechanism, a movable impact platform, a hydraulic drive system and a ground guide mechanism. The movable impact platform is composed of a truss structure and a high-speed guide rail, which is bolted to the truss structure through a guide rail mounting hole. The hydraulic drive system is a high-speed servo proportional hydraulic system and is fixed to the ground through the ground fixing mechanism. The ground guide mechanism is two rows of guide blocks arranged in parallel through the gantry. The movable impact platform is connected to the hydraulic drive system and placed on the ground guide mechanism. This document realizes the basket dropping function through roller contact, which has the adverse effects of difficult-to-ignore gap vibration and friction.

[0006] In CN106644347B of Nanjing University of Aeronautics and Astronautics, a landing gear landing device drop test device and test method are involved, which includes a lifting system, a drop system, a load collection system and a rack system. The lifting system is fixed on the rack system, the drop system is arranged on the rack system and can vertically slide, and the load collection system is arranged below the drop system. The landing attitude of the landing leg in the drop system is adjusted, and the landing attitude is fixed. The drop system is lifted to a predetermined height, and the drop system freely slides along the sliding support column under the action of gravity, so that the foot pad on the landing leg contacts the six-dimensional force platform to simulate the collision process of the landing gear and the ground, and the data is recorded. The invention has the advantages of simple structure, small structure weight and high test measurement precision. The document aims to reduce the gap of structural cooperation by the sliding form of linear ball bearing, but essentially still uses rolling friction.

[0007] In CN117606731A of Xi'an Aircraft Design Institute of China Aviation Industry Group, a fall test platform hanging basket lifting control device and method are involved, belonging to the field of aircraft structure test. The device includes a fall test platform and a display control ground station. The fall test platform includes a lifting actuator, a weighing sensor, an electric control permanent magnet, a hanging basket, a position sensor, and a fall test platform frame. The fall test platform frame constitutes the support structure of the device. The lifting actuator is installed on the upper part of the fall test platform frame to provide power for the lifting operation of the landing gear test piece. The lower side of the lifting actuator is connected to the electric control permanent magnet through the weighing sensor. The electric control permanent magnet can lose or generate magnetism in the powered state, thereby releasing or attracting the hanging basket. The lower side of the hanging basket is fixed with the landing gear test piece, and the lower side of the hanging basket is provided with a displacement sensor. The display control ground station is connected to the above-mentioned components, and can control the lifting actuator to perform lifting operation and control the electric control permanent magnet to generate or lose magnetic force. The feature of this document is to lift the hanging basket through the display control ground station, focusing on the hanging basket lifting device, and not involving the vibration gap and friction problem of the above-mentioned volume.

[0008] In CN117191316A of Shenyang Aerospace University and Liaoning General Aviation Research Institute, a fall test platform for testing aircraft landing gear and a fall test method are involved. The fall test platform adopts a chain plate-roller structure, and the rotation of the driving chain plate on the impact platform is used to simulate the horizontal speed of the landing gear and the ground when the aircraft lands, greatly saving the occupied space of the equipment, and realistically simulating the speed change of the aircraft landing. The landing gear can be effectively tested. The feature of this document is to use a chain plate-roller structure fall test platform to simulate the horizontal speed of the landing gear and the ground when the aircraft lands by rotating the driving chain plate on the impact platform, focusing on the force platform, and not involving the vibration and friction during the landing motion and process of the landing gear.

[0009] In CN117141743B of China Aircraft Strength Research Institute, a kind of bearing release device for aircraft full machine drop test belongs to the field of aircraft test technology, including base, the front end of the base is provided with quick release mechanism, the rear end of the base is provided with two front height adjusting seats and two rear height adjusting seats side by side, one front hinged seat is fixedly connected above each of the two front height adjusting seats, an H-shaped support arm is hingedly connected on the two front hinged seats, one rear hinged seat is fixedly connected above each of the two rear height adjusting seats, an H-shaped crushing rod is hingedly connected on the two rear hinged seats, a vertical support arm is hingedly connected on the two sides of the upper side of the H-shaped crushing rod, and the front ends of the two vertical support arms are hingedly connected with the two sides of the top of the H-shaped support arm. The feature of this document is that the base is provided with a quick release mechanism, the dynamic response of the aircraft body in the working condition of hooking free flight of carrier-based aircraft is simulated by the H-shaped support arm and the H-shaped crushing rod, and it does not involve the drop test movement and vibration and friction of the landing gear during the process.

[0010] In CN215573665U of Zhejiang Honghu Wings Aviation Technology Co., Ltd., a small landing gear drop test bed is disclosed, which includes a test bed frame, a test bed step including a stand, a hanging basket arranged in the test bed frame and capable of sliding down along the slide of the test bed frame, a landing gear mounting seat protruding downward arranged at the bottom of the hanging basket, and an impact platform arranged at the lower end of the landing gear. The small landing gear drop test bed can test the integrated landing gear of a small aircraft taking off by sliding. The feature of this document is that the hanging basket capable of sliding down along the slide of the test bed frame is arranged in the test bed frame, which is suitable for small landing gears, but still has the vibration and friction problems of the above-mentioned rollers.

[0011] In CN112479034A of China Helicopter Design Institute, a guide rail-free release attitude control device and method are involved. The center of gravity coordinates of the test piece hanging basket are determined, the installation position of the suspension point position adjusting mechanism on the hanging basket is determined according to the relationship between the suspension point coordinates and the center of gravity coordinates. In the specific implementation of the test, the attitude angle of the hanging basket during the suspension and release process is measured in real time by a double-axis inclination sensor, and the horizontal and vertical positions of the suspension point of the hanging basket are continuously adjusted by the suspension point position adjusting mechanism, thereby adjusting the attitude angle of the hanging basket, until the horizontal and vertical attitude angles measured by the double-axis inclination sensor can stably meet the test requirements before the release operation is implemented. The feature of this document is that after the center of gravity coordinates of the test piece hanging basket are determined, the installation position of the suspension point position adjusting mechanism on the hanging basket is determined according to the relationship between the suspension point coordinates and the center of gravity coordinates, to ensure that the landing gear can fall vertically, but it does not involve the guidance of the landing gear during the falling process.

[0012] In CN110887632B of COMAC Shenfei Civil Aircraft Co., Ltd., a whole unmanned aerial vehicle drop test device is involved, which mainly consists of a frame, a triggering device, an unhooking device and a whole aircraft lifting device. A lifting arm is arranged at the top of the frame, one end of the lifting arm is provided with a manual winch, and the other end is provided with a fixed pulley. One end of a steel wire rope is connected with the manual winch, and the other end is connected with the unhooking device through the fixed pulley. The main body of the whole lifting device is a mouth-shaped frame, a positioning beam is arranged at the center of the mouth-shaped frame, a lifting ring base is connected to the positioning beam through adjusting bolts, a lifting ring is arranged on the lifting ring base, and the moving direction of the adjusting bolt drives the lifting ring to coincide with the center surface of the aircraft to be tested. The lifting ring is connected with the unhooking device, the steel wire rope pulls the unhooking device to move upwards and then contacts with the triggering device to realize the triggering and unhooking action. The drop test device can lift the whole unmanned aerial vehicle to a predetermined height in a horizontal attitude, and then release the unmanned aerial vehicle in a horizontal attitude through a release mechanism to implement the drop test. It can be seen that the document also does not involve guiding the landing gear during the falling process.

[0013] The above-mentioned various modes have the following disadvantages:

[0014] 1) The basket and the stand column are in contact through the roller, there is a large gap, which can change the attitude of the basket, and it is difficult to accurately simulate the landing attitude;

[0015] 2) There is friction between the roller and the stand slide rail, and the friction is unstable and changes with the change of temperature, weight and attitude, which can cause uncertainty of the kinetic energy of the landing gear hitting the ground;

[0016] 3) Due to the gap and friction between the roller and the column, the stand will vibrate during the falling process, which introduces additional noise and makes the result processing difficult. SUMMARY

[0017] Based on the above defects of the prior art, the present application provides a landing gear drop test device, which comprises:

[0018] a stand;

[0019] a connecting rod mechanism, which is installed on the stand, and each connecting rod in the connecting rod mechanism can move relative to the stand;

[0020] a landing gear support, which is pivotally installed on a corresponding connecting rod in the connecting rod mechanism, and the landing gear support is configured to allow a landing gear to be tested to be fixedly installed thereon so that the landing gear to be tested moves with the landing gear support,

[0021] wherein the connecting rod mechanism is configured to enable the landing gear support to move linearly with the movement of the connecting rod mechanism.

[0022] The present application realizes the release function of the landing gear drop shock through a simple connecting rod mechanism. Compared with the prior art, the landing gear drop shock device of the present application replaces the hanging basket roller mechanism with a connecting rod mechanism with a rocker arm, avoids the gap vibration and friction between the hanging basket and the stand column, ensures the energy and landing attitude when the landing gear hits the ground, and improves the precision of the drop shock. At the same time, the mechanism has simple structure, small space occupation, and strong universality. By changing the number of rocker arms, the demand of different release quality can be met, and the landing gear of various types of aircrafts can be applied.

[0023] According to the preferred embodiment of the landing gear drop shock device of the present application, further comprising: a landing gear holding device configured to be switched between a holding state of holding the landing gear to be tested at an undropped height and a release state of releasing the landing gear to be tested to allow it to freely fall.

[0024] According to the preferred embodiment of the landing gear drop shock device of the present application, further comprising: a force measuring platform fixed relative to the stand and configured to sense the load of the landing gear drop shock.

[0025] According to the preferred embodiment of the landing gear drop shock device of the present application, the connecting rod mechanism is configured to form a planar four-bar linkage with the stand, the planar four-bar linkage includes two rocking connecting rods directly connected with the stand and one intermediate connecting rod not directly connected with the stand, and wherein the landing gear support is mounted on the intermediate connecting rod.

[0026] According to the preferred embodiment of the landing gear drop shock device of the present application, the two rocking connecting rods have the same length and are configured to be simultaneously in a horizontal position.

[0027] According to the preferred embodiment of the landing gear drop shock device of the present application, each connecting rod is respectively hinged to the stand or other connecting rod in two different planes parallel to the movement plane of the planar four-bar linkage at both ends.

[0028] According to the preferred embodiment of the landing gear drop shock device of the present application, at least two groups of the connecting rod mechanisms are included, and wherein the landing gear support is respectively pivotally connected with a corresponding one of the connecting rods in each group of the connecting rod mechanisms.

[0029] The mechanism can realize various equivalent mass release requirements by increasing or decreasing the number of release rocker arm mechanisms, and is suitable for various types of aircraft landing gears.

[0030] According to the preferred embodiment of the landing gear drop shock device of the present application, at least two groups of the same connecting rod mechanisms are included.

[0031] At least two sets of the releasing rocker arm mechanism are adopted at the time of drop shock, and according to the characteristics of the planar linkage mechanism, the landing gear can further move along the center line of the releasing rocker arm mechanism.

[0032] According to the preferred embodiment of the landing gear drop shock device, the same linkage mechanism is arranged at different positions of the platform along the movement direction of the landing gear support.

[0033] In addition, the application also relates to a landing gear drop shock method, which comprises the following steps:

[0034] The landing gear drop shock device is provided as described in the foregoing embodiments.

[0035] The landing gear to be tested is installed in the landing gear drop shock device through the landing gear support.

[0036] The landing gear support together with the landing gear to be tested is lifted to a desired height, and the landing gear support is kept at the desired height through the landing gear holding device.

[0037] The landing gear support is released through the landing gear holding device, so that the landing gear support together with the landing gear to be tested falls and hits the force platform.

[0038] According to the preferred embodiment of the landing gear drop shock method, a counterweight installation step is further included, in which a counterweight with a mass of the releasing mass converted according to the work of the drop shock system minus half of the total weight of the linkage structure is installed on the landing gear drop shock device, so that the counterweight moves together with the landing gear to be tested.

[0039] In addition to the technical effects described above with respect to the drop shock device, according to the method of the application, the fixed basket is released at a specified height at the time of landing gear drop shock, the rocker arm swings downward together with the basket, the linkage rotates around the hinge point on the basket along with the swing of the rocker arm, the landing gear support falls along a straight line, hits the ground force platform, and the drop shock process is completed, which is simple and easy to operate.

[0040] In summary, the application obtains a simple structure, less space occupation, and high feasibility of the rocker arm type drop shock releasing mechanism and the corresponding test method, which can be applied to the design and development of aircraft landing gears.

[0041] The patent realizes the releasing function of the aircraft landing gear device through a simple mechanism. Compared with the prior art, the basket roller mechanism is replaced by the rocker arm mechanism, so that the gap vibration and friction problems between the basket and the platform column are avoided, and the precision of the drop shock is improved.

[0042] The mechanism of the present application is simple in structure, small in space occupation, very concise, and high in feasibility, and can be applied to the landing gear drop tests of various types of aircraft. More specifically, the specific embodiments of the present application can also ensure the vertical falling of the landing gear, can avoid the influence of the deviation of the center of gravity of the falling body from the center of the landing gear contact point, and can also fully utilize the weight of the motion mechanism itself as an additional counterweight otherwise required in the drop test. BRIEF DESCRIPTION OF DRAWINGS

[0043] The present document includes drawings to provide further understanding of various embodiments. The drawings are incorporated into and form part of the specification.

[0044] The accompanying drawings illustrate various embodiments described herein and, together with the written description, serve to explain the principles and operations of the claimed subject matter.

[0045] With reference to the above objects, the technical features of the present application are described below, and its advantages are apparent from the following detailed description with reference to the accompanying drawings, which show by way of example the preferred embodiments of the present application, without limiting the scope of the present application.

[0046] In the drawings:

[0047] Figure 1 A perspective view of a preferred embodiment of the landing gear drop test device according to the present application is shown, in which the two swing links in each group of link mechanisms are in a horizontal position.

[0048] Figure 2 A perspective view of a preferred embodiment of the landing gear drop test device according to the present application is shown, in which the two swing links in each group of link mechanisms are in a horizontal position. Figure 1 A perspective view of a preferred embodiment of the landing gear drop test device according to the present application is shown, in which the two swing links in each group of link mechanisms are in a horizontal position. Figure 1 The position of the landing gear to be tested in

[0049] List of reference signs

[0050] 100 landing gear drop test device

[0051] 110 test stand

[0052] 111 test stand column

[0053] 112 test stand beam

[0054] 113 lug

[0055] 120 link mechanism

[0056] 121 swing link

[0057] 122 intermediate link

[0058] 130 landing gear support

[0059] 131 counterweight

[0060] 140 landing gear holding device

[0061] 150 force measuring platform

[0062] 160 pivotal coupling

[0063] 200 landing gear to be measured DETAILED DESCRIPTION

[0064] Embodiments of the present application will now be described in detail, with examples shown in the drawings and described hereinafter.

[0065] Although the present application will be described with reference to the example embodiments, it is to be appreciated that the description is not intended to limit the present application to those example embodiments. Rather, the present application is intended to cover all alternatives, modifications, equivalents and other embodiments that can be included within the spirit and scope of the present application.

[0066] For the purpose of explaining and precisely defining the technical solutions of the present application, the terms "upper", "lower", "inner" and "outer" are used to describe the features of the example embodiments shown in the drawings with reference to the positions of the features.

[0067] The preferred embodiments of the landing gear shock absorbing device of the present application will be described in detail below with reference to the accompanying drawings.

[0068] As shown in Figure 1 and Figure 2 The landing gear shock absorbing device 100 according to the present application includes a platform 110, a linkage mechanism 120 and a landing gear support 130. In addition, the landing gear shock absorbing device 100 according to the present application can further include a landing gear holding device 140 and a force measuring platform 150. Figure 1 and Figure 2 The preferred embodiments of the landing gear shock absorbing device of the present application shown in

[0069] In the preferred embodiments shown in the drawings, reference is made in particular to Figure 1 It is to be appreciated that the platform 110 can include four vertically arranged platform columns 111. The four platform columns 111 are preferably arranged in a square shape. The four platform columns 111 are preferably arranged in a square shape. Figure 1The four corners of the roughly rectangular stand base shown in the figure are located at the bottom. It should be noted that the stand base shown in the figure is not required, as long as the installation environment can meet the requirements for the stable installation of the four stand columns 111. However, it is understood that an integrated stand base can be more conducive to the stable arrangement of the stand columns 111. In the case of a stand base, the stand base may include but is not limited to the rectangular, square or other polygonal shapes shown in the figure, circular, oval, elliptical, etc., which will not be described in detail here. Moreover, although the stand base shown in the figure is a roughly plate-shaped member, those skilled in the art will understand that the stand base can also take other forms, such as a block, a detachable component, etc. It should also be noted that although the figure shows four stand columns 111 arranged in a preferred rectangular shape, the number and arrangement of the stand columns 111 are not limited to this. Fewer, such as three, or more, such as five or more, can be provided. Finally, and more importantly, the basic form of the platform formed by the platform columns 111 shown in the figure is merely an illustration of a preferred embodiment. Those skilled in the art may employ various other structures to form the platform 110, such as a truss structure, a box-like structure, or the like, at least partially or entirely, as long as the various other components of the landing gear drop shock device 100 can be mounted thereon. These details will not be repeated here. Furthermore, other optional components of the platform 110 are further described below.

[0070] The linkage mechanism 120 is mounted on the platform 110, and each link in the linkage mechanism 120 is movable relative to the platform 110. According to the basic concept of the present invention, the movement of the linkage mechanism 120 is used to guide the drop motion of the landing gear 200 to be tested. Therefore, the linkage structure 120 only needs to meet basic motion requirements, including but not limited to a single independent linkage mechanism 120 having only one degree of freedom.

[0071] The landing gear support 130, also referred to as a hanging basket in the art, can be pivotally mounted on a corresponding link in the linkage 120, for example, via a pivot connection 160 such as a screw. The landing gear support 130 is configured to allow the landing gear 200 to be fixedly mounted thereon so that the landing gear 200 to be tested moves along with the landing gear support 130.

[0072] Preferably, and if Figure 1 As shown in FIG, the landing gear frame 300 may carry one or more counterweights 131, for example, inside the landing gear frame or elsewhere.

[0073] The linkage 120 is configured such that the landing gear support 130 is capable of linear movement with the movement of the linkage 120. Those skilled in the art, under the teaching of the inventive concept of the present application, can select appropriate linkages 120, including planar and non-planar linkages, four-bar or more linkages, to achieve a specific landing gear movement pattern according to the actual situation. The more preferred arrangement of the linkage 120 shown in the drawings will be further described below.

[0074] In the preferred embodiment shown in Figure 1 and Figure 2 , the linkage 120 is configured to form a planar four-bar linkage with the gantry 110. As more clearly shown in Figure 2 , the planar four-bar linkage moves in a plane parallel to or coinciding with the plane of the drawing. Figure 2

[0075] The planar four-bar linkage includes two swing links 121 directly connected to the gantry 110 and one intermediate link 122 not directly connected to the gantry 110, and wherein the landing gear support 130 is mounted on the intermediate link 122. Those skilled in the art can understand that the two swing links 121, also referred to as swing arms, can swing within a certain range in the above-mentioned plane. And the intermediate link 122 can make a combination of rotation and translation, or rotational translation, in the corresponding plane.

[0076] As shown in the embodiments in the drawings, each link can be hingedly connected to the gantry 110 or other links at two ends in two different planes parallel to the movement plane of the planar four-bar linkage. In other words, each link has two ends each provided with two hinged portions, and the two hinged portions provide the same hinged movement. It can be understood that the link mentioned herein is a concept in mechanical principles. For example, as shown in Figure 1 , each swing link 121 can be formed by a single plate, more specifically a single plate frame, and each intermediate link 122 can be formed by two parallel arranged elongated members substantially having a diamond shape. But the specific form of the swing link 121 and the intermediate link 122 of the present application is not limited thereto, but can also include various other components that can function as a linkage, such as a round bar, a block, etc., which will not be described here.

[0077] In addition, as also shown in Figure 1 , the gantry cross beams 112 can be arranged between the plurality of gantry uprights 111 on which the single swing link 121 is mounted. The gantry cross beams 112 can be arranged substantially parallel to the swing link 121, and Figure 1 ​The middle is the horizontal arrangement. Each swing link 121 can be hingedly connected relative to the trestle 110 by means of a pivot coupling 160, such as a screw, by means of a lug 113 arranged on the respective trestle beam 112.

[0078] Also, as illustratively and not limitingly, the swing links 121 and the intermediate links 122 can preferably be pivotally connected to each other by means of a pivot coupling 160, such as a screw.

[0079] It can be understood that the pivotally hingedly connecting by means of the pivot coupling 160, more specifically a screw, as described above is only illustrative, and those skilled in the art can select other common pivotally hingedly connecting means according to actual conditions, such as shape fitting and the like, which will not be described here again.

[0080] More preferably, and as shown in Figure 1 and Figure 2 The landing gear 100 of the application can comprise at least two sets of link mechanisms 120, more preferably exactly two sets of link mechanisms 120. And wherein the landing gear support 130 is pivotally connected to a respective one of the links in each set of link mechanisms 120, such as preferably the intermediate link 122 of each set of link mechanisms 120. It is further more preferable that the at least two, or exactly two, sets of the same link mechanisms 120 are exactly the same link mechanisms 120. In the case of providing multiple sets of the same link mechanisms 120, the same link mechanisms 120 can preferably be arranged at different positions of the trestle 110 along the movement direction of the landing gear support 130, i.e. Figure 1 and Figure 2 The vertical direction.

[0081] In order to conveniently achieve the desired landing gear landing movement, the two swing links 121 are of the same length and are configured to be in the horizontal position at the same time. It is pointed out that although the two swing links 121 of each set of link mechanisms 120 in the preferred embodiment shown in the figure are of the same size, the swing links 121 of different sets of link mechanisms 120 can be of different sizes. However, it can be understood that even the two swing links 121 in the same set of link mechanisms 120 can have different lengths, as long as the intermediate intermediate link 122 therebetween can achieve the desired landing movement path. In addition, it is also pointed out that in this preferred manner, although the swing links 121 of each set of link mechanisms 120 are in the horizontal position at the same time, the timing of the swing links 121 of different sets of link mechanisms 120 being in their horizontal positions can be in sequence according to actual conditions, and it is not required that the swing links 121 of all sets of link mechanisms 120 are in the horizontal position at the same time.

[0082] More preferably, the specific linkage configuration dimensions of the different sets of linkage mechanisms 120, including the length of the links and / or the manner of connection, can be identical. In this case, the movement of each linkage mechanism 120 can preferably be identical.

[0083] Furthermore, more preferably, the intermediate link 122 can be in a vertical position when the two swing links 121 are simultaneously in a horizontal position. Also, the landing gear support 130 can preferably be pivotally connected to the midpoint of the intermediate link 122. This arrangement allows for a more engineering-practical manner of ensuring the vertical drop of the landing gear, which is particularly significant for convenient on-site operation. The landing gear holding device 140 is configured to switch between a holding state in which the landing gear under test 200 is held at an undropped height, and a release state in which the landing gear under test 200 is released to allow it to freely drop. The landing gear holding device 140 can be in the form of a telescopic sleeve, for example. The landing gear holding device 140 can also be fixed to the top plate of the gantry 110 as shown in the figure. The top plate of the gantry 110 can be provided at the top end of each gantry column 111, opposite the aforementioned gantry base. The above description regarding the gantry base also applies to the top plate, including but not limited to the fact that the top plate is not necessary, and the shape and specific form of the top plate are not limited to the rectangular plate shown in the figure, and the like, which will not be described here again.

[0084] The force platform 150 is fixed relative to the gantry 110 and is configured to sense the load of the landing gear under test 200 drop.

[0085] The landing gear drop method according to the present application will be briefly described below, which can be a drop test method, and includes the following steps:

[0086] A landing gear drop device 100 according to the foregoing description of the present application is provided;

[0087] The landing gear under test 200 is installed in the landing gear drop device 100 through the landing gear support 130;

[0088] The landing gear support 130 together with the landing gear under test 200 is lifted to a desired height, and the landing gear support 130 is held at the desired height by the landing gear holding device 140; and

[0089] The landing gear support 130 is released by the landing gear holding device 140, so that the landing gear support 130 together with the landing gear under test 200 drops and hits the force platform 150.

[0090] According to the preferred embodiment, a step of installing the counterweight 131 can be included, for example, before the landing gear support 130 is installed or after the landing gear support 130 has been installed. In this step of installing the counterweight 131, a counterweight 131 having a mass equal to the drop mass according to the total work of the landing gear shock absorption system minus half the total weight of the linkage 120 can be installed on the landing gear shock absorption system 100, and more particularly on the landing gear support 130, for example, in a horizontal grid provided in the landing gear support 130, so that the counterweight moves together with the landing gear 200 to be tested.

[0091] For example, if the total work of the landing gear shock absorption system should be, according to the requirements of the landing gear shock absorption test:

[0092] W0 = m0gh,

[0093] wherein,

[0094] m0 is the drop mass, which can be calculated according to the above formula according to the total work,

[0095] h is the lifting height of the landing gear shock absorption system.

[0096] Since the center of gravity of a common linkage is approximately equivalent to the geometric center, in this case, the center of gravity of the linkage 120 can be approximately considered to be displaced by 1 / 2h after one landing.

[0097] At this time, the linkage 120 does work on the entire landing gear shock absorption system as w1 = m1g*1 / 2h = 1 / 2m1gh, and m1 is the total weight of the linkage 120, so the mass m2 of the counterweight can be calculated by the following formula, i.e.

[0098] m2 = m0 - 1 / 2m1,

[0099] That is, at this time, half the weight of the linkage 120 also acts as a counterweight in addition to the provided counterweight.

[0100] The preferred embodiments of the present application have been described in detail above, but it should be understood that aspects of the embodiments can be modified to employ aspects, features and concepts of various patents, applications and publications, if appropriate, to provide additional embodiments.

[0101] In view of the detailed description above, various modifications to the embodiments described herein can be readily apparent.

[0102] In general, the use of the terms "may" and "may" followed by a conjugation to the word "have" are used herein in their permissive sense (i.e., having the potential to, or being able to, but not necessarily doing), and accordingly the configuration and / or arrangement of one or more elements will not, by itself, invoke a permissive usage.

Claims

1. A landing gear shock device (100), include: Stand (110); a connecting rod mechanism (120), wherein the connecting rod mechanism (120) is mounted on the platform (110), and each connecting rod in the connecting rod mechanism (120) is movable relative to the platform (110); A landing gear bracket (130), wherein the landing gear bracket (130) is pivotally mounted on a corresponding link in the link mechanism (120), and the landing gear bracket (130) is configured to allow a landing gear to be tested (200) to be fixedly mounted thereon so that the landing gear to be tested (200) moves along with the landing gear bracket (130). The connecting rod mechanism (120) is configured such that the landing gear support (130) can move linearly along with the movement of the connecting rod mechanism (120).

2. The landing gear shock device (100) according to claim 1, It is characterized in that Also includes: A landing gear holding device (140) is configured to be switchable between a holding state for holding a landing gear (200) to be tested at a height where the landing gear (200) is not dropped and a releasing state for releasing the landing gear (200) to be tested and allowing it to fall freely.

3. The landing gear shock device (100) according to claim 1, It is characterized in that Also includes: A force measuring platform (150) is fixed relative to the platform (110) and is configured to sense the load of a landing gear (200) under test when it is subjected to a drop shock.

4. The landing gear shock device (100) according to claim 1, It is characterized in that The link mechanism (120) is configured to form a planar four-bar linkage with the platform (110), the planar four-bar linkage comprising two rocking links (121) directly connected to the platform (110) and an intermediate link (122) not directly connected to the platform (110), wherein the landing gear support (130) is mounted on the intermediate link (122).

5. The landing gear shock device (100) according to claim 4, It is characterized in that The two rocking connecting rods (121) have the same rod length and are configured to be in a horizontal position at the same time.

6. The landing gear shock device (100) according to claim 4, It is characterized in that Each link is hingedly connected to the platform (110) or other links at both ends in two different planes parallel to the motion plane of the planar four-bar linkage.

7. The landing gear drop shock device (100) according to any one of claims 1 to 6, It is characterized in that It comprises at least two groups of the link mechanisms (120), and wherein, The landing gear bracket (130) is pivotally connected to a corresponding link in each set of the link mechanisms (120).

8. The landing gear shock device (100) according to claim 7, It is characterized in that It comprises at least two sets of identical link mechanisms (120).

9. The landing gear shock device (100) according to claim 8, It is characterized in that The same link mechanism (120) is distributed at different positions of the platform (110) along the movement direction of the landing gear support (130).

10. A landing gear drop shock method comprising the following steps: Providing a landing gear drop shock device (100) according to any one of claims 1 to 9; The landing gear to be tested (200) is installed in the landing gear drop shock device (100) via the landing gear bracket (130); Lifting the landing gear support (130) together with the landing gear to be tested (200) to a desired height, and holding the landing gear support (130) at the desired height by a landing gear holding device (140); and The landing gear support (130) is released by the landing gear holding device (140), so that the landing gear support (130) and the landing gear to be tested (200) fall down and hit the force measuring platform (150).

11. The landing gear drop shock method according to claim 10, It is characterized by: The method further comprises a counterweight installation step, in which a counterweight having a mass equal to half the total weight of the connecting rod structure (120) minus the drop mass obtained by converting the work of the landing system is installed on the landing gear landing device (100), so that the counterweight moves together with the landing gear (200) to be tested.

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