Landing gear shock absorber and method

Abstract

A landing gear drop device (100) comprises a base frame (110), a linkage mechanism (120) mounted on the base frame (110) and each linkage of the linkage mechanism (120) is movable relative to the base frame (110), and a landing gear support (130) pivotally mounted on a corresponding linkage of the linkage mechanism (120) and configured to have a landing gear (200) to be tested fixedly mounted thereon so as to move with the landing gear support (130), wherein the linkage mechanism (120) is configured to enable the landing gear support (130) to move linearly with the movement of the linkage mechanism (120). The drop device avoids clearance vibration and friction of the roller components, ensures the energy and landing attitude when the landing gear hits the ground, and improves the accuracy of the drop. A landing gear drop method using the above drop device is also disclosed.

Description

Technical Field

[0001] This invention belongs to the field of mechanical design, specifically to the field of aircraft structural testing, and more specifically relates to an aircraft landing gear drop test device for landing gear drop tests, etc. Background Technology

[0002] Landing gear landing vibration technology is a ground load verification technology that plays a crucial role in aircraft design. Its purpose is to verify the landing gear landing dynamic characteristics, the correctness of the landing load simulation analysis model, and the energy absorption capacity of the buffer system.

[0003] Currently, landing gear drop tests are conducted using a vertical drop method. During the drop test, the landing gear basket, along with the landing gear under test, slides downwards along the motion guide mechanism on the drop test platform using rollers. This method is used in Chinese invention patent application CN101520364A and Chinese utility model patent CN204495533.

[0004] The following list further illustrates the state of the prior art by providing other patent literature in this field.

[0005] CN101532903B from Nanjing University of Aeronautics and Astronautics discloses a drop test device for a movable impact platform, applicable to drop and roll tests of aircraft landing gear, taxiing characteristics tests, tire static characteristics tests, and tire dynamic characteristics tests. It includes a gantry, a ground fixing mechanism, a deployment and retraction mechanism, a basket, landing gear, a basket guide mechanism and a clearance adjustment mechanism, a movable impact platform, a hydraulic drive system, and a ground guide mechanism. The movable impact platform consists of a truss structure and high-speed guide rails. The high-speed guide rails are bolted to the truss structure through guide rail mounting holes. The hydraulic drive system is a high-speed servo proportional hydraulic system fixed to the ground by the ground fixing mechanism. The ground guide mechanism consists of two parallel rows of guide sliders passing through the gantry. The movable impact platform is connected to the hydraulic drive system and placed on the ground guide mechanism. This document achieves the basket deployment function through roller contact, which has unavoidable adverse effects from clearance vibration and friction.

[0006] CN106644347B from Nanjing University of Aeronautics and Astronautics discloses a landing gear drop test device and method, including a lifting system, a drop system, a load acquisition system, and a test platform system. The lifting system is fixed on the test platform system, the drop system is mounted on the test platform system and can slide vertically, and the load acquisition system is located below the drop system. The landing attitude of the landing legs in the drop system is adjusted and fixed. The drop system is then lifted to a predetermined height, and under the action of gravity, it slides freely along a sliding support, allowing the foot pads on the landing legs to contact a six-dimensional force measurement platform to simulate the collision process between the lander and the ground, and the data is recorded. This invention has a simple structure, low weight, and high experimental measurement accuracy. While this document aims to reduce the clearance of the structural fit through the sliding mechanism of linear ball bearings, it essentially still uses rolling friction.

[0007] CN117606731A, from the Xi'an Aircraft Design Institute of Aviation Industry Corporation of China, discloses a drop test rig basket lifting control device and method, belonging to the field of aircraft structural testing. The device includes a drop test rig frame and a display and control ground workstation. The drop test rig frame includes a lifting actuator, a weighing sensor, an electrically controlled permanent magnet, a basket, a position sensor, and a drop test rig frame. The drop test rig frame constitutes the supporting structure of the device. The lifting actuator is installed on the drop test rig frame and provides power for the lifting and lowering operation of the landing gear test piece. The lower side of the lifting actuator is connected to the electrically controlled permanent magnet via a weighing sensor. The electrically controlled permanent magnet can lose or generate magnetism when energized, thereby releasing or attracting the basket. The landing gear test piece is fixedly installed on the lower side of the basket, and a displacement sensor is provided on the lower side of the basket. The display and control ground workstation is connected to the above components and can control the lifting actuator to perform lifting operations and control the electrically controlled permanent magnet to generate or lose magnetism. The distinctive feature of this document is that it focuses on the lifting device of the suspended platform by raising the platform through a ground control workstation, without addressing the vibration gap and friction issues of the aforementioned volume.

[0008] CN117191316A, published by Shenyang Aerospace University and Liaoning General Aviation Research Institute, discloses a drop test platform and its drop test method for aircraft landing gear. The drop test platform adopts a chain-plate-roller structure, simulating the horizontal velocity of the landing gear relative to the ground during aircraft landing by rotating the transmission chain on the impact platform. This significantly saves equipment space and realistically simulates the speed changes during aircraft landing, enabling effective testing of the aircraft landing gear. The key feature of this document is its use of a chain-plate-roller structure for the drop test platform, simulating the horizontal velocity of the landing gear relative to the ground during aircraft landing by rotating the transmission chain on the impact platform. It focuses on the force measurement platform but does not address the landing gear's drop motion, vibration, or friction during the process.

[0009] CN117141743B, published by the China Aircraft Strength Research Institute, discloses a load-bearing release device for a full-aircraft drop test, belonging to the field of aircraft testing technology. It includes a base with a quick-release mechanism at its front end. At the rear end of the base are two forward height adjustment seats and two rear height adjustment seats arranged side-by-side. A forward hinge seat is fixedly connected above each of the two forward height adjustment seats, and an H-shaped support arm is hinged to both of them. A rear hinge seat is fixedly connected above each of the two rear height adjustment seats, and an H-shaped crushing rod is hinged to both of them. A vertical support arm is hinged to each of the upper sides of the H-shaped crushing rod, with the front ends of the two vertical support arms hinged to the top sides of the H-shaped support arm. The key feature of this document is the quick-release mechanism on the base. The H-shaped support arms and H-shaped crushing rod simulate the dynamic response of a carrier-based aircraft during free flight and hook-up conditions, without involving the landing gear's drop motion or the vibration and friction during the process.

[0010] CN215573665U, published by Zhejiang Honghuyi Aviation Technology Co., Ltd., discloses a small landing gear drop test bench, including a test bench frame, test steps including columns, a basket that slides down the test bench frame, a downward-protruding landing gear mounting seat at the bottom of the basket, and impact platforms on both sides of the lower end of the landing gear. This small landing gear drop test bench can perform drop tests on the integrated landing gear of small runway-takeoff aircraft. The feature of this document is the basket that slides down the test bench frame, making it suitable for small landing gears. However, the vibration and friction problems of the aforementioned rollers still exist.

[0011] CN112479034A, from the China Helicopter Design Institute, discloses a railless deployment attitude control device and method. The method involves determining the center of gravity coordinates of the test specimen basket, and then determining the installation position of the suspension point position adjustment mechanism on the basket based on the relationship between the suspension point coordinates and the center of gravity coordinates. During the test, a dual-axis tilt sensor measures the attitude angles of the basket in real time during suspension and deployment. The suspension point position adjustment mechanism continuously adjusts the lateral and longitudinal positions of the basket's suspension points, thereby adjusting the basket's attitude angles until the lateral and longitudinal attitude angles measured by the dual-axis tilt sensor stably meet the test requirements before deployment. A key feature of this document is that after determining the center of gravity coordinates of the test specimen basket, the installation position of the suspension point position adjustment mechanism on the basket is determined based on the relationship between the suspension point coordinates and the center of gravity coordinates, ensuring the landing gear can descend vertically, without addressing the guidance of the landing gear during descent.

[0012] CN110887632B, published by AVIC Shenyang Aircraft Corporation, describes a whole-aircraft drop test device for unmanned aerial vehicles (UAVs). This device mainly consists of a frame, a triggering device, a release device, and a whole-aircraft lifting frame. A boom is located at the top of the frame, with a manual winch at one end and a fixed pulley at the other. A steel cable connects to the manual winch at one end and to the release device at the other end, passing over the fixed pulley. The main body of the lifting frame is a U-shaped frame with a positioning beam at its center. A lifting ring base is connected to the positioning beam via adjusting bolts. A lifting ring is mounted on the lifting ring base, and the adjusting bolts cause the lifting ring to move in a direction aligning with the center plane of the aircraft under test. The lifting ring is connected to the release device; the steel cable pulls the release device upwards, causing it to contact the triggering device, thus triggering the release action. This drop test device can lift the entire UAV to a predetermined altitude in a horizontal attitude and then release it horizontally via a release mechanism to conduct a drop test. However, this document does not address the guidance of the landing gear during the descent.

[0013] The above methods all have the following shortcomings:

[0014] 1) The basket and the platform column are in contact through rollers, and there is a large gap, which will cause the basket's attitude to change, making it difficult to accurately simulate the landing attitude;

[0015] 2) There is friction between the rollers and the platform rails, and this friction is unstable and changes with temperature, release weight, and release attitude, which leads to uncertainty in the kinetic energy of the landing gear when it hits the ground;

[0016] 3) Due to the gap and friction between the rollers and the column, the platform will vibrate during the descent, introducing additional noise and making it difficult to process the results. Summary of the Invention

[0017] In view of the above-mentioned deficiencies in the prior art, the present invention provides a landing gear shock absorption device, comprising:

[0018] stand;

[0019] A linkage mechanism, which is mounted on the platform and whose links are movable relative to the platform;

[0020] A landing gear bracket, pivotally mounted on a corresponding link in the linkage mechanism, and configured to allow the landing gear under test to be fixedly mounted thereon so that the landing gear under test moves with the landing gear bracket.

[0021] The linkage mechanism is configured such that the landing gear support can move linearly as the linkage mechanism moves.

[0022] This invention achieves the landing gear drop function through a simple linkage mechanism. Compared with existing technologies, the landing gear drop device of this invention replaces the basket roller mechanism with a linkage mechanism with rocker arms, avoiding gap vibration and friction between the basket and the platform column, ensuring the energy and landing attitude of the landing gear upon impact with the ground, and improving the drop accuracy. At the same time, this mechanism has a simple structure, occupies little space, and is highly versatile. By changing the number of rocker arms, it can meet the requirements of different drop qualities and is suitable for landing gear of various types of aircraft.

[0023] A preferred embodiment of the landing gear drop device according to the present invention further includes: a landing gear holding device configured to switch between a holding state in which the landing gear under test is held at a height not falling and a releasing state in which the landing gear under test is released to allow it to fall freely.

[0024] A preferred embodiment of the landing gear drop device according to the present invention further includes: a force measuring table, the force measuring table being fixed relative to the frame and configured to sense the load of the landing gear drop under test.

[0025] According to a preferred embodiment of the landing gear shock device of the present invention, the linkage mechanism is configured to form a planar four-bar linkage with the platform. The planar four-bar linkage includes two rocking links directly connected to the platform and an intermediate link not directly connected to the platform, wherein the landing gear bracket is mounted on the intermediate link.

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

[0027] According to a preferred embodiment of the landing gear shock device of the present invention, each of the links is hinged at both ends to the platform or other links in two different planes parallel to the motion plane of the planar four-bar linkage.

[0028] According to a preferred embodiment of the landing gear shock device of the present invention, it includes at least two sets of the linkage mechanisms, wherein the landing gear support is pivotally connected to a corresponding link in each set of the linkage mechanisms.

[0029] This device can meet various equivalent mass delivery requirements by increasing or decreasing the number of deployment rocker arm mechanisms, and is suitable for various types of aircraft landing gear.

[0030] A preferred embodiment of the landing gear shock absorber according to the present invention includes at least two identical sets of the linkage mechanism.

[0031] During the landing, at least two sets of deployment rocker arm mechanisms are used. Based on the characteristics of planar linkage mechanisms, this can further facilitate the movement of the landing gear along the center line of the deployment rocker arm mechanisms.

[0032] According to a preferred embodiment of the landing gear shock absorber of the present invention, the same linkage mechanism is distributed at different positions on the platform along the movement direction of the landing gear support.

[0033] Furthermore, the present invention also relates to a landing gear shock method, comprising the following steps:

[0034] Provide a landing gear shock absorber as described in the foregoing embodiments;

[0035] The landing gear to be tested is installed in the landing gear shock device via the landing gear bracket;

[0036] The landing gear support, together with the landing gear under test, is raised to a desired height, and the landing gear support is held at the desired height using a landing gear holding device; and

[0037] The landing gear support is released by the landing gear retaining device, causing the landing gear support and the landing gear under test to fall and impact the force measuring platform.

[0038] According to a preferred embodiment of the landing gear drop method of the present invention, the method further includes a counterweight installation step, in which a counterweight with a mass equal to half the total weight of the linkage structure minus the release mass calculated according to the power of the drop system is installed on the landing gear drop device so that the counterweight moves together with the landing gear to be tested.

[0039] In addition to the technical effects described above regarding the drop-shock device, when the landing gear drops according to the method of the present invention, the fixed basket is released at a specified height, the rocker arm swings downward with the basket, and the connecting rod rotates around the hinge point on the basket with the swing of the rocker arm, so that the landing gear support falls in a straight line and hits the ground force measuring platform to complete the drop-shock process. The operation is simple and easy.

[0040] In summary, this invention provides a simple, space-saving, and highly feasible rocker arm-type drop-drop mechanism and corresponding testing method, which can be applied to the design and development of aircraft landing gear.

[0041] This patent implements the deployment function of the aircraft landing gear assembly through a simple mechanism. Compared with the prior art, this invention replaces the basket roller mechanism with a rocker arm mechanism, avoiding the gap vibration and friction problems between the basket and the platform column, and improving the accuracy of the drop.

[0042] The mechanism of this invention is simple in structure, occupies little space, is very concise, and highly feasible, applicable to landing gear drop tests of various types of aircraft. More specifically, the specific embodiments of this invention can also ensure that the landing gear falls vertically, avoiding the influence of the deviation between the center of gravity of the landing gear and the center of the landing gear contact point, and can also make full use of the weight of the motion mechanism itself as a counterweight that would otherwise need to be added during drop tests. Attached Figure Description

[0043] This document includes accompanying drawings to provide a further understanding of various embodiments. The drawings are incorporated in and form part of this specification.

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

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

[0046] In the attached image:

[0047] Figure 1 A perspective view of a preferred embodiment of the landing gear shock absorber according to the present invention is shown, wherein the two rocking links in each linkage mechanism are in a horizontal position.

[0048] Figure 2 It shows Figure 1 The schematic front view of the preferred embodiment of the landing gear shock device according to the present invention is shown, wherein the landing gear under test is relative to... Figure 1 The position in the middle was raised vertically upwards.

[0049] List of reference numerals

[0050] 100 Landing Gear Shock Absorption Device

[0051] 110 units

[0052] 111 support columns

[0053] 112 crossbeams

[0054] 113 Earpiece

[0055] 120 linkage mechanism

[0056] 121 Shaking the linkage

[0057] 122 Intermediate Link

[0058] 130 landing gear support

[0059] 131 counterweight

[0060] 140 Landing Gear Retention Device

[0061] 150 Force measuring table

[0062] 160 Pivoting Connector

[0063] 200 landing gears to be tested Detailed Implementation

[0064] Embodiments of the invention will now be described in detail, examples of which are shown in the accompanying drawings and described below.

[0065] Although the invention will be described in conjunction with exemplary embodiments, it should be understood that this specification is not intended to limit the invention to the embodiments illustrated. Rather, the invention is intended to cover not only these exemplary embodiments, but also various alternatives, modifications, equivalents, and other embodiments that may be included within the spirit and scope of the invention.

[0066] To facilitate explanation and precise definition of the technical solutions of the present invention, the terms "upper," "lower," "inner," and "outer" are used to describe these features with reference to the positions of features in the exemplary embodiments shown in the accompanying drawings.

[0067] The preferred embodiments of the shock-drop device of the present invention will be described in detail below with reference to the accompanying drawings.

[0068] like Figure 1 and Figure 2 As shown, the landing gear shock absorber 100 according to the present invention includes: a platform 110, a linkage mechanism 120, and a landing gear support 130. Furthermore, Figure 1 and Figure 2 The preferred embodiment of the drop device of the present invention shown may further include: a landing gear holding device 140 and a force measuring table 150.

[0069] In the preferred embodiment shown in the figure, particularly refer to Figure 1 It is understood that the platform 110 may include four vertically arranged platform columns 111. These four platform columns 111 are preferably arranged in... Figure 1The figure shows the four corners of a roughly rectangular support base. It should be noted that the support base shown is not strictly necessary; any suitable installation environment is sufficient for the stable installation of the four support columns 111. However, it is understood that an integrated support base is more conducive to the stable arrangement of the support columns 111. In the case of a support base, the base may include, but is not limited to, the rectangle, square, other polygons, circles, ovals, ellipses, etc., as shown in the figure, which will not be elaborated further here. Furthermore, although the support base shown in the figure is generally plate-shaped, those skilled in the art will understand that the support base can also take other forms, such as block-shaped pieces, detachable components, etc. It should also be noted that although the figure shows a preferred rectangular arrangement of four support columns 111, the number and arrangement of the support columns 111 are not limited to this; fewer, such as three support columns 111, or more, such as five or more support columns 111, may be used. Finally, and more importantly, the basic form of the platform constructed by the platform columns 111 shown in the figure is only a preferred embodiment. Those skilled in the art can use various other structures to construct the platform 110, such as at least partially or entirely including truss structures, box-shaped structures, etc., as long as various other components of the landing gear shock absorber 100 can be installed on it, which will not be elaborated here. In addition, other optional components of the platform 110 are further described below.

[0070] The linkage mechanism 120 is mounted on the test stand 110, and each link in the linkage mechanism 120 can move relative to the test stand 110. According to the basic concept of the present invention, the landing gear 200 under test is to be guided by the movement of the linkage mechanism 120. Therefore, the linkage structure 120 here only needs to meet the basic motion requirements, including but not limited to a single independent linkage mechanism 120 having only one degree of freedom.

[0071] The landing gear bracket 130, also referred to in the art as a basket, can be pivotally mounted on a corresponding link in the linkage 120 via a pivoting connection 160 such as a screw, and the landing gear bracket 130 is configured to allow the landing gear 200 under test to be fixedly mounted thereon so that the landing gear 200 under test moves with the landing gear bracket 130.

[0072] Preferably, and as Figure 1 As shown, the landing gear support 300 may, for example, carry one or more counterweights 131 inside or in other locations.

[0073] The linkage mechanism 120 is configured such that the landing gear support 130 can move linearly in accordance with the movement of the linkage mechanism 120. Those skilled in the art, inspired by this inventive concept, can select a suitable linkage mechanism 120 based on actual conditions, including planar and non-planar linkage mechanisms, four-bar or more linkage mechanisms, to achieve specific landing gear movement modes. The following further elaborates on the more preferred arrangement of the linkage mechanism 120 shown in the figures.

[0074] exist Figure 1 and Figure 2 In the preferred embodiment shown, the linkage 120 is configured to form a planar four-bar linkage with the platform 110. For example... Figure 2 As more clearly illustrated in the diagram, this planar four-bar linkage is in relation to... Figure 2 The figure moves in a plane that is parallel to or coincides with the plane on which it is located.

[0075] The planar four-bar linkage includes 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 bracket 130 is mounted on the intermediate link 122. Those skilled in the art will understand that the two rocking links 121, also referred to as rocker arms, can oscillate within a certain range within the aforementioned plane. Furthermore, the intermediate link 122 can perform rotational and translational movements, or a combination of rotation and translational movements, within the corresponding plane.

[0076] As shown in the embodiment, each link can be hinged at both ends to the platform 110 or other links in two different planes parallel to the motion plane of the planar four-bar linkage. In other words, each link has two hinges at both ends, and the two hinges provide the same hinged motion. It is understood that the link mentioned herein is a mechanical concept. For example, as... Figure 1 As shown, each rocking link 121 may be composed of a single plate-like member, more specifically a single plate-like frame member, while each intermediate link 122 may be composed of two parallel, generally rhomboid, elongated members. However, the specific forms of the rocking links 121 and intermediate links 122 of the present invention are not limited to this, but may also include various other components that can function as a linkage mechanism, such as round rods, block-like members, etc., which will not be described in detail here.

[0077] In addition, as in Figure 1 As shown, a platform crossbeam 112 may be provided between the multiple platform columns 111 on which a single rocking link 121 is mounted. The platform crossbeam 112 may be arranged approximately parallel to the rocking link 121. Figure 1The arrangement is horizontal. Each rocking link 121 can be hinged relative to the platform 110 by means of a lug 113 arranged on the corresponding platform beam 112 via a pivoting connector 160 such as a screw.

[0078] Furthermore, as an illustration and not a limitation, the rocking link 121 and the intermediate link 122 may preferably be pivotally connected to each other by a pivoting connector 160 such as a screw.

[0079] It is understood that the pivoting connection using pivot connector 160, or more specifically screws, described above is merely illustrative. Those skilled in the art can select other common pivoting connection methods, such as form fit, etc., according to the actual situation, which will not be elaborated here.

[0080] More preferably, and as Figure 1 and Figure 2 As shown, the landing gear support 100 of the present invention may include at least two sets of linkage mechanisms 120, more preferably exactly two sets of linkage mechanisms 120. The landing gear support 130 is pivotally connected to a corresponding link in each set of linkage mechanisms 120, for example, preferably the intermediate link 122 of each set of linkage mechanisms 120. More preferably, the aforementioned at least two sets, or exactly two sets, of identical linkage mechanisms 120 are completely identical linkage structures 120. When multiple sets of identical linkage mechanisms 120 are provided, the identical linkage mechanisms 120 are preferably along the direction of movement of the landing gear support 130, i.e. Figure 1 and Figure 2 The vertical distribution is arranged at different positions on the platform 110.

[0081] To facilitate the desired landing gear drop motion, the two rocking links 121 are of the same length and configured to be simultaneously in a horizontal position. It should be noted that although the two rocking links 121 of each group of linkages 120 shown in the preferred embodiment are of the same size, the dimensions of the rocking links 121 in different groups of linkages 120 can be different. However, it is understood that even two rocking links 121 in the same group of linkages 120 can have different lengths, as long as the intermediate link 122 can achieve the desired drop motion path. Furthermore, it should be noted that in this preferred embodiment, although the rocking links 121 of each group of linkages 120 are simultaneously in a horizontal position, the order in which the rocking links 121 of different groups of linkages 120 are in their respective horizontal positions can vary depending on the actual situation, and it is not required that all groups of linkages 120 have their rocking links 121 in a horizontal position simultaneously.

[0082] More preferably, the specific link configuration dimensions, including link length and / or connection method, of different groups of linkage mechanisms 120 can be completely identical. In this case, the motion of each linkage mechanism 120 can preferably be completely identical.

[0083] Furthermore, more preferably, when both rocking links 121 are simultaneously in a horizontal position, the intermediate link 122 can be in a vertical position. Preferably, the landing gear bracket 130 is pivotally connected to the midpoint of the intermediate link 122. This arrangement allows for vertical descent of the landing gear in a more practical engineering manner, particularly facilitating on-site operation. The landing gear holding device 140 is configured to switch between a holding state that keeps the landing gear 200 under test at a height not lowered and a released state that allows the landing gear 200 under test to fall freely. The landing gear holding device 140 can be, for example, in the form of a telescopic sleeve. The landing gear holding device 140 can also be fixed to the top plate of the platform 110 as shown in the figure. The top plate of the platform 110 can be located at the top of each platform column 111, opposite the aforementioned platform base. The above description of the stand 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, etc., which will not be elaborated here.

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

[0085] The following is a brief description of the landing gear drop test method according to the present invention, which can be a drop test method and includes the following steps:

[0086] The present invention provides a landing gear shock absorber 100 as described above;

[0087] The landing gear 200 to be tested is installed in the landing gear shock device 100 via the landing gear bracket 130;

[0088] The landing gear bracket 130, together with the landing gear 200 under test, is raised to the desired height, and the landing gear bracket 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 retaining device 140, causing the landing gear support 130 and the landing gear 200 under test to fall and impact the force measuring platform 150.

[0090] According to a preferred embodiment, for example, before installing the landing gear bracket 130 or after the landing gear bracket 130 has been installed, a counterweight 131 installation step may be included. In this counterweight 131 installation step, a counterweight 131 with a mass equal to half the total weight of the linkage mechanism 120 minus the release mass calculated according to the drop system power can be installed on the landing gear drop device 100, more specifically, on the landing gear bracket 130, for example, placed in a horizontal grid provided in the landing gear bracket 130, so that the counterweight moves together with the landing gear 200 under test.

[0091] For example, according to the requirements of the drop test, the total power of the drop test system should be:

[0092] W0 = m0gh,

[0093] in,

[0094] m0 represents the mass of the material being delivered, which can be calculated from the total work output using the formula described above.

[0095] h represents the lifting height of the drop-earthquake system.

[0096] Considering that common linkage mechanisms are geometrically regular, their center of gravity can be approximated as being at their geometric center. Therefore, in this case, it can be approximately assumed that after one drop, the center of gravity displacement of linkage mechanism 120 is 1 / 2h.

[0097] At this point, the work done by the linkage mechanism 120 in the entire drop vibration system is w1 = m1g * 1 / 2h = 1 / 2m1gh, where m1 is the total weight of the linkage mechanism 120. Therefore, the mass m2 of the counterweight can be calculated using the following formula:

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

[0099] At this point, in addition to the counterweight, half of the weight of the linkage mechanism 120 is also used as a counterweight.

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

[0101] Given the detailed description above, various readily conceivable variations can be made to the embodiments described herein.

[0102] Generally speaking, the terminology used in the claims should not be considered as limited to the specific embodiments disclosed in the specification and claims, but should be understood to include all possible embodiments together with the full scope of equivalents enjoyed by the claims.

Claims

1. A landing gear shock absorber (100). include: Stand (110); A linkage mechanism (120) is mounted on the platform (110), and each link in the linkage mechanism (120) is movable relative to the platform (110); A landing gear bracket (130) is pivotally mounted on a corresponding link in the linkage mechanism (120), and the landing gear bracket (130) is configured to allow a landing gear under test (200) to be fixedly mounted thereon so that the landing gear under test (200) moves with the landing gear bracket (130). The linkage mechanism (120) is configured such that the landing gear support (130) can move linearly with the movement of the linkage mechanism (120). The linkage mechanism (120) is configured to form a planar four-bar linkage with the platform (110). The planar four-bar linkage includes two rocking links (121) directly connected to the platform (110) and an intermediate link (122) not directly connected to the platform (110). The landing gear support (130) is mounted on the intermediate link (122).

2. The landing gear shock absorber (100) according to claim 1. Its features are, Also includes: A landing gear holding device (140) is configured to switch between a holding state in which the landing gear under test (200) is held at a height not falling and a released state in which the landing gear under test (200) is released to allow it to fall freely.

3. The landing gear shock absorber (100) according to claim 1. Its features are, Also includes: A force measuring table (150) is fixed relative to the frame (110) and configured to sense the drop load of the landing gear (200) under test.

4. The landing gear shock absorber (100) according to claim 1. Its features are, The two rocking links (121) are of the same length and are configured to be in a horizontal position at the same time.

5. The landing gear shock absorber (100) according to claim 1. Its features are, Each of the links is hinged at both ends to the platform (110) or other links in two different planes parallel to the motion plane of the planar four-bar linkage.

6. The landing gear shock absorber (100) according to any one of claims 1 to 5. Its features are, It includes at least two sets of the linkage mechanisms (120), wherein the landing gear support (130) is pivotally connected to a corresponding link in each set of the linkage mechanisms (120).

7. The landing gear shock absorber (100) according to claim 6. Its features are, Includes at least two identical sets of the linkage mechanism (120).

8. The landing gear shock absorber (100) according to claim 7. Its features are, The same linkage mechanism (120) is distributed at different positions on the platform (110) along the direction of movement of the landing gear support (130).

9. A landing gear shock method, comprising the following steps: A landing gear shock absorber (100) as described in any one of claims 1 to 8 is provided. The landing gear (200) to be tested is installed in the landing gear shock device (100) via the landing gear bracket (130); The landing gear bracket (130) together with the landing gear under test (200) is raised to the desired height, and the landing gear bracket (130) is held at the desired height by the landing gear holding device (140); and The landing gear support (130) is released by the landing gear retaining device (140), so that the landing gear support (130) together with the landing gear under test (200) falls and impacts the force measuring table (150).

10. The landing gear shock method according to claim 9, Its features are, It also includes a counterweight installation step, in which a counterweight with a mass equal to half the total weight of the connecting rod structure (120) minus the mass of the drop mass calculated according to the drop system power is installed on the landing gear drop device (100) so that the counterweight moves together with the landing gear (200) to be tested.

Images