Aircraft landing gear aerodynamic load simulation loading device

Abstract

The present invention discloses a device for simulating the pneumatic load of an aircraft landing gear, and belongs to the technical field of aircraft landing gear testing. The device includes a parallel four-bar linkage, a fixed support, a motor, a gearbox, a hydraulic loading cylinder, a connector, a force sensor, and an angular displacement sensor. The parallel four-bar linkage includes a connecting rod, a crank, and a rocker arm, and the crank and the rocker arm are respectively hinged to the fixed support; the motor cooperates with the gearbox to drive the crank to rotate around the fixed support; the hydraulic loading cylinder is installed on the connecting rod and connected to the aircraft landing gear through a connector; the force sensor is installed on the connector; and the angular displacement sensor is installed on the fixed support. Compared with the prior art, the present invention has the following advantages: it can realize the simulated loading of air resistance load, and the hydraulic loading cylinder does not need a large stroke to meet the test requirements of landing gears of various heights. While meeting the requirements of use, it has a simple structure, and is easy and convenient to control and operate.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft landing gear testing, and in particular to an aircraft landing gear aerodynamic load simulation loading device. Background Art

[0002] To improve aircraft aerodynamics, designers adapted traditional landing gear with a tail wheel or skids into a retractable design, a design that has subsequently become commonplace on nearly all aircraft. The landing gear must be retracted and extended during flight. Due to air resistance, the landing gear is subject to aerodynamic forces during retraction and extension. These forces are evenly distributed across the gear, affecting the retraction and extension functions of the landing gear strut actuators and uplocks. Therefore, during the design and development phase of an aircraft landing gear, an aerodynamic load simulator is required to conduct retraction and extension tests to simulate normal landing gear operation.

[0003] Currently, simulating aerodynamic loads during landing gear retraction and extension tests remains a challenge. This difficulty stems from the need to maintain the horizontal direction of the aerodynamic loads and simulate their magnitude. Developed countries typically test the landing gear directly in a wind tunnel. This method produces data that approximates actual landing gear extension and retraction, providing reliable results. However, this method is expensive, complex, and difficult to conduct in a short period of time.

[0004] Domestic testing is primarily conducted without wind tunnels, so accurately simulating the aerodynamic loads during landing gear retraction and extension on a ground test bench is crucial for retraction and extension fatigue testing. However, existing testing methods are complex and difficult to operate, making it difficult to simulate air resistance loads and unable to meet the testing requirements of landing gear at various heights.

[0005] Therefore, there is an urgent need for a new aircraft landing gear aerodynamic load simulation loading device to solve the above technical problems. Summary of the Invention

[0006] The object of the present invention is to provide an aircraft landing gear aerodynamic load simulation loading device, which utilizes a motor, a gearbox, a parallel four-bar linkage and a hydraulic loading cylinder to achieve simulated loading of air resistance loads. The hydraulic loading cylinder does not require a large stroke to meet the testing requirements of landing gears of various heights. While meeting the requirements of use, the structure is simple and the control and operation are simple and convenient, thereby solving at least one technical problem involved in the background technology.

[0007] In order to solve the above-mentioned technical problems, the present invention is achieved as follows:

[0008] The present invention provides an aircraft landing gear pneumatic load simulation loading device, comprising a parallel four-bar linkage, a fixed support, a motor, a gearbox, a hydraulic loading cylinder, a connecting piece, a force sensor, and an angular displacement sensor, wherein:

[0009] The parallel four-bar linkage includes a connecting rod, a crank hinged at one end to the connecting rod, and a rocker hinged at one end to the connecting rod, wherein the crank and the rocker are arranged in parallel and spaced apart, and the other ends of the crank and the rocker are respectively hinged to the fixed support;

[0010] The motor cooperates with the gearbox to drive the crank to rotate around the fixed support;

[0011] The hydraulic loading cylinder is mounted on the connecting rod, and the output end of the hydraulic loading cylinder is connected to the aircraft landing gear through the connecting member;

[0012] The force sensor is mounted on the connecting member to detect the magnitude of the loading force output by the hydraulic loading cylinder;

[0013] The angular displacement sensor is mounted on the fixed support to detect the swing angle of the crank.

[0014] Optionally, the number of the cranks is two, and they are arranged in parallel and at intervals; the number of the rocker rods is two, and they are arranged in parallel and at intervals.

[0015] Optionally, the connecting rod is in the shape of a flat plate.

[0016] Optionally, the tail end of the hydraulic loading cylinder is hinged to the connecting rod, and the head end is arranged on the connecting rod through a cylinder self-balancing mechanism.

[0017] Optionally, the cylinder self-balancing structure uses a cylindrical helical compression spring to balance the weight of the hydraulic loading cylinder.

[0018] Optionally, the crank and the rocker arm are hinged to the fixed support and the connecting rod respectively through a hinge mechanism.

[0019] Optionally, the articulated mechanism includes a support arm, a transmission shaft, a sleeve and a rolling bearing, one end of the transmission shaft is fixed on the support arm, the crank or the rocker arm is rotatably mounted on the other end of the transmission shaft through the rolling bearing, and the sleeve is mounted on the transmission shaft and located between the two rolling bearings.

[0020] Optionally, the gearbox includes an output gear, which is fixedly connected to the sleeve for fixedly connecting the crank, and the angular displacement sensor detects the rotation angle of the output gear to detect the swing angle of the crank.

[0021] Optionally, the connecting member is a steel wire rope.

[0022] Optionally, the articulated mechanism further includes an end cover which is sleeved on the transmission shaft and fixed to the crank or the rocker arm by screws.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) A parallel four-bar linkage is used to follow the load action point of the landing gear in real time. The cylinder is installed on the connecting rod, and a hydraulic loading cylinder with a large stroke is not required.

[0025] (2) The motor and gearbox drive the parallel four-bar linkage, which has large driving torque and compact structure;

[0026] (3) By configuring the cylinder deadweight balancing device, the influence of the cylinder weight on the loading accuracy can be eliminated. At the same time, it also allows the use of steel wire ropes instead of force sensor adapter rods in the loading path;

[0027] (4) A steel wire rope is used instead of the force sensor adapter rod, and the distance between the oil cylinder and the landing gear load point can be easily adjusted. When the landing gear is tested in high and low temperature environments, the oil cylinder does not need to work in high and low temperature environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work, among which:

[0029] Figure 1 This is a schematic diagram of the overall structure of the aircraft landing gear aerodynamic load simulation loading device provided by the present invention;

[0030] Figure 2 A schematic diagram of the overall structure of the parallel four-bar linkage provided by the present invention;

[0031] Figure 3 A schematic diagram of the assembly structure of the crank and the hinge structure provided by the present invention;

[0032] Figure 4 This is a schematic diagram of the assembly structure of the rocker arm and the hinge structure provided by the present invention. DETAILED DESCRIPTION

[0033] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0034] See Figures 1 to 4 As shown, an embodiment of the present invention provides an aircraft landing gear aerodynamic load simulation loading device, including a parallel four-bar linkage 1, a fixed support 2, a motor 3, a gearbox 4, a hydraulic loading cylinder 5, a connecting piece 6, a force sensor 7 and an angular displacement sensor 8.

[0035] The parallel four-bar linkage 1 includes a connecting rod 11, a crank 12 hinged at one end to the connecting rod 11, and a rocker 13 hinged at one end to the connecting rod 11. The crank 12 and the rocker 13 are arranged in parallel and spaced apart, and the other ends of the crank 12 and the rocker 13 are respectively hinged to the fixed support 2.

[0036] Furthermore, the number of the cranks 12 is two and they are arranged in parallel and spaced apart; the number of the rocker rods 13 is two and they are arranged in parallel and spaced apart; and the connecting rod 11 is in the shape of a flat plate.

[0037] It should be noted that the motion characteristics of the parallelogram linkage 1 are that the crank 12 and rocker arm 13 rotate at the same angle, while the connecting rod 11 moves horizontally and remains parallel to the frame. Furthermore, the parallelogram linkage 1 is designed as a frame structure, with the connecting rod 11 designed as a platform, and the hydraulic loading cylinder 5 is mounted on the platform. The motion objective of the parallelogram linkage 1 is to ensure that the hydraulic loading cylinder 5 follows the position of the center of gravity (equivalent load application point) of the aircraft landing gear 9 in real time as it is raised and lowered. The function of the hydraulic loading cylinder 5 is to apply an equivalent aerodynamic load to the aircraft landing gear load application point.

[0038] The motor 3 is preferably a servo motor, which cooperates with the gearbox 4 to drive the crank 12 to rotate around the fixed support 2.

[0039] The hydraulic loading cylinder 5 is mounted on the connecting rod 11 , and the output end of the hydraulic loading cylinder 5 is connected to the aircraft landing gear 9 through the connecting member 6 .

[0040] The tail end of the hydraulic loading cylinder 5 is hinged to the connecting rod 11 , and the head end is arranged on the connecting rod 11 through the cylinder self-balancing mechanism 10 .

[0041] The cylinder self-balancing structure 10 uses a cylindrical helical compression spring to balance the weight of the hydraulic loading cylinder 5. By adjusting the length of the compression spring, the elastic force is equal to the gravity of the cylinder, thereby achieving self-balancing.

[0042] In a specific embodiment, the connecting member 6 is a steel wire rope. In this way, the steel wire rope is used instead of the force sensor adapter rod, and the distance between the cylinder and the load application point of the landing gear is convenient to adjust. When testing the landing gear in high and low temperature environments, the cylinder does not need to work in high and low temperature environments.

[0043] The force sensor 7 is mounted on the connecting member 6 to detect the magnitude of the loading force output by the hydraulic loading cylinder 5 .

[0044] The angular displacement sensor 8 is mounted on the fixed support 2 to detect the swing angle of the crank 12 .

[0045] The crank 12 and the rocker arm 13 are hinged to the fixed support 2 and the connecting rod 11 respectively through hinge mechanisms.

[0046] The hinge mechanism includes a support arm 14, a transmission shaft 15, a sleeve 16 and a rolling bearing 17. One end of the transmission shaft 15 is fixed to the support arm 14, and the crank 12 or the rocker arm 13 is rotatably sleeved on the other end of the transmission shaft 15 through the rolling bearing 17. The sleeve 16 is sleeved on the rotating shaft 15 and is located between the two rolling bearings 17.

[0047] Specifically, the transmission shaft 15 and the support arm 14 are fixed via a flat key 20 .

[0048] The gearbox 4 includes an output gear 41, which is fixedly connected to the sleeve 16 used to securely connect the crank 12. The angular displacement sensor 8 detects the rotation angle of the output gear 41 to detect the swing angle of the crank 12. Thus, the rotation angle provided by the motor 3 is converted into the required rotation angle via the gearbox 4 and transmitted to the parallelogram linkage 1. The rotation angle is measured by the angular displacement sensor 8 at the output gear 41. Furthermore, the crank 12 of the parallelogram linkage 1 converts the motion into the movement of the hydraulic loading cylinder 5 following the center of gravity (equivalent load application point) of the aircraft landing gear 9. The control strategy is based on the relationship between the piston rod displacement of the landing gear actuator (9) and the landing gear swing angle, as well as the relationship between the motor rotation angle and the crank angle of the quadrilateral linkage mechanism. This relationship is then derived: actuator rod displacement, motor rotation angle, and quadrilateral linkage crank angle. The measured displacement of the landing gear actuator piston rod is converted into the input for the crank angle control of the parallelogram linkage mechanism. The crank angle (equipped with an angular displacement sensor and a test channel) is used as feedback to control the motor rotation angle, achieving closed-loop control of the equivalent load application point. The extreme positions of the load application point are at the fully retracted and fully extended positions of the landing gear (9). The stroke of the parallelogram linkage mechanism (1) must meet these extreme position requirements. While achieving load application point tracking, a simulated pneumatic load is applied to the landing gear (9) by controlling the operating pressure of the hydraulic loading cylinder (5). A force sensor (7) measures the load force. The measured value of the force sensor (7) serves as the control feedback, enabling closed-loop control of the pneumatic load.

[0049] The hinge mechanism further includes an end cover 19 which is sleeved on the transmission shaft 15 and fixed to the crank 12 or the rocker 13 via screws 18 .

[0050] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0051] Furthermore, it should be noted that the scope of the methods and systems of the present invention is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in reverse order, depending on the functions involved. For example, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Furthermore, features described with reference to certain examples may be combined in other examples.

[0052] The above describes the embodiments of the present invention, but the present invention is not limited to the above specific implementation methods. The above specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are protected by the present invention.

Claims

1. An aircraft landing gear aerodynamic load simulation loading device, characterized in that: It includes a parallel four-bar linkage, a fixed support, a motor, a gearbox, a hydraulic loading cylinder, a connecting piece, a force sensor, and an angular displacement sensor, wherein: The parallel four-bar linkage includes a connecting rod, a crank hinged at one end to the connecting rod, and a rocker hinged at one end to the connecting rod, wherein the crank and the rocker are arranged in parallel and spaced apart, and the other ends of the crank and the rocker are respectively hinged to the fixed support; The motor cooperates with the gearbox to drive the crank to rotate around the fixed support; The hydraulic loading cylinder is mounted on the connecting rod, and the output end of the hydraulic loading cylinder is connected to the aircraft landing gear through the connecting member; The force sensor is mounted on the connecting member to detect the magnitude of the loading force output by the hydraulic loading cylinder, and the crank of the parallel four-bar linkage converts the motion into the hydraulic loading cylinder following the center of gravity movement of the aircraft landing gear; The angular displacement sensor is mounted on the fixed support to detect the swing angle of the crank, and the crank swing angle measurement result is used as feedback to control the rotation angle of the motor to achieve closed-loop control of equivalent load application point following.

2. The aircraft landing gear aerodynamic load simulation loading device according to claim 1, characterized in that: There are two cranks, which are arranged in parallel and spaced apart; there are two rocker rods, which are arranged in parallel and spaced apart.

3. The aircraft landing gear aerodynamic load simulation loading device according to claim 1 or 2, characterized in that: The connecting rod is in a flat plate shape.

4. The aircraft landing gear aerodynamic load simulation loading device according to claim 3, characterized in that: The tail end of the hydraulic loading oil cylinder is hinged on the connecting rod, and the head end is arranged on the connecting rod through an oil cylinder self-balancing mechanism.

5. The aircraft landing gear aerodynamic load simulation loading device according to claim 4, characterized in that: The oil cylinder self-balancing structure uses a cylindrical helical compression spring to balance the weight of the hydraulic loading oil cylinder.

6. The aircraft landing gear aerodynamic load simulation loading device according to claim 1, characterized in that: The crank and the rocker arm are hinged to the fixed support and the connecting rod respectively through a hinge mechanism.

7. The aircraft landing gear aerodynamic load simulation loading device according to claim 6, characterized in that: The articulated mechanism includes a support arm, a transmission shaft, a sleeve and a rolling bearing. One end of the transmission shaft is fixed on the support arm, and the crank or the rocker arm is rotatably sleeved on the other end of the transmission shaft through the rolling bearing. The sleeve is sleeved on the transmission shaft and is located between the two rolling bearings.

8. The aircraft landing gear aerodynamic load simulation loading device according to claim 7, characterized in that: The gearbox includes an output gear, which is fixedly connected to the sleeve for fixedly connecting the crank. The angular displacement sensor detects the rotation angle of the output gear to detect the swing angle of the crank.

9. The aircraft landing gear aerodynamic load simulation loading device according to claim 7, characterized in that: The connecting piece is a steel wire rope.

10. The aircraft landing gear aerodynamic load simulation loading device according to claim 7, characterized in that: The hinge mechanism further includes an end cover which is sleeved on the transmission shaft and fixed to the crank or the rocker arm by screws.

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