Aircraft landing gear aerodynamic load simulation loading device

Abstract

The invention discloses an aircraft landing gear aerodynamic load simulation loading device, and belongs to the technical field of aircraft landing gear tests. The device comprises a parallel four-bar mechanism, a fixed support, a motor, a gearbox, a hydraulic loading oil cylinder, a connecting piece, a force sensor and an angular displacement sensor, the parallel four-bar mechanism comprises a connecting rod, a crank and a swing rod, and the crank and the swing rod are respectively hinged to the fixed support; the motor is matched with the gearbox to drive the crank to rotate around the fixed support; the hydraulic loading oil cylinder is mounted on the connecting rod and is connected with an aircraft landing gear through a connecting piece; the force sensor is mounted on the connecting piece; and the angular displacement sensor is arranged on the fixed support. Compared with the prior art, the air resistance load simulation test device has the advantages that air resistance load simulation loading can be achieved, the hydraulic loading oil cylinder can meet the test requirements of undercarriages of various heights without a large stroke, and the air resistance load simulation test device is simple in structure and easy and convenient to control and operate under the condition that the use requirements are met.

Description

Technical Field

[0001] The 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] In order to improve the aerodynamic characteristics of the aircraft, designers designed the traditional landing gear with a tail wheel or skid into a retractable landing gear, and almost all aircraft later adopted this design. The aircraft needs to complete the retraction and lowering of the landing gear when flying in the air. Due to the influence of air resistance, the landing gear will be affected by aerodynamic forces when it is retracted and extended. The aerodynamic force is evenly distributed on the landing gear, affecting the retraction and extension functions of the landing gear strut actuator and the upper lock. Therefore, during the design and development stage of the aircraft landing gear, an aerodynamic load simulation device is required to perform a retraction and extension test to simulate the normal use of the landing gear.

[0003] At present, the simulation of aerodynamic loads has always been a difficult point in the landing gear retraction and extension test. The difficulty lies in the need to ensure the horizontal direction of the aerodynamic load at all times and simulate the size of the load. Developed countries generally place the landing gear in a wind tunnel for direct testing. The test data obtained by this method is close to the actual landing gear retraction and extension, and the results are true and reliable, but the research cost is high, the test is complex, and it is not easy to be carried out in a short time.

[0004] Domestic tests are basically conducted without wind tunnel conditions, so it is crucial to accurately simulate the aerodynamic load of the landing gear retraction and extension process on a ground test bench for the retraction and extension fatigue test. However, the existing test method has a complex structure and is difficult to operate. It is difficult to simulate the loading of air resistance loads and cannot meet the test requirements of landing gears of various heights.

[0005] Therefore, a new type of aircraft landing gear aerodynamic load simulation loading device is urgently needed to solve the above technical problems. Summary of the invention

[0006] The purpose of the present invention is to provide an aircraft landing gear pneumatic 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, and the hydraulic loading cylinder does not require a large stroke to meet the test 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: 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: The parallel four-bar linkage mechanism comprises a connecting rod, a crank with one end hinged to the connecting rod, and a swing rod with one end hinged to the connecting rod, the crank and the swing rod are arranged in parallel and spaced apart, and the other ends of the crank and the swing rod 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 piece; The force sensor is mounted on the connecting piece to detect the magnitude of the loading force output by the hydraulic loading cylinder; The angular displacement sensor is mounted on the fixed support to detect the swing angle of the crank.

[0008] 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.

[0009] Optionally, the connecting rod is in the shape of a flat plate.

[0010] 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.

[0011] Optionally, the cylinder self-balancing structure uses a cylindrical helical compression spring to balance the weight of the hydraulic loading cylinder.

[0012] Optionally, the crank and the rocker arm are respectively hinged to the fixed support and the connecting rod through a hinge mechanism.

[0013] 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.

[0014] 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 swing angle of the crank by detecting the rotation angle of the output gear.

[0015] Optionally, the connecting member is a steel wire rope.

[0016] Optionally, the articulated mechanism further comprises an end cover which is sleeved on the transmission shaft and fixed to the crank or the rocker arm by screws.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (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. (2) The motor and gearbox are used to drive the parallel four-bar linkage, which has large driving torque and compact structure; (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, a steel wire rope can be used in the loading path to replace the force sensor adapter rod; (4) A steel wire rope is used to replace the force sensor adapter rod, and the distance between the oil cylinder and the landing gear load point can be easily adjusted. When testing the landing gear 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

[0018] 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. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which: Figure 1 The overall structural schematic diagram of the aircraft landing gear aerodynamic load simulation loading device provided by the present invention; Figure 2 The overall structural schematic diagram of the parallel four-bar linkage provided by the present invention; Figure 3 A schematic diagram of the assembly structure of the crank and the hinge structure provided by the present invention; Figure 4 This is a schematic diagram of the assembly structure of the swing arm and the hinge structure provided by the present invention. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] See also Figures 1 to 4 As shown, an embodiment of the present invention provides an aircraft landing gear pneumatic 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.

[0021] 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 rod 13 hinged at one end to the connecting rod 11. The crank 12 and the rocker rod 13 are arranged in parallel and spaced apart, and the other ends of the crank 12 and the rocker rod 13 are respectively hinged to the fixed support 2.

[0022] Furthermore, the number of the cranks 12 is two and they are arranged in parallel and at intervals; the number of the rocker rods 13 is two and they are arranged in parallel and at intervals; and the connecting rod 11 is in the shape of a plate.

[0023] It should be noted that, due to the movement characteristics of the parallel four-bar linkage 1, the crank 12 and the rocker 13 have the same rotation angle, and the connecting rod 11 moves horizontally and is always parallel to the frame. Furthermore, the parallel four-bar linkage 1 is designed as a frame structure, the connecting rod 11 is designed as a platform, and the hydraulic loading cylinder 5 is installed on the platform. The movement goal of the parallel four-bar linkage 1 is to ensure that the hydraulic loading cylinder 5 follows the center of gravity (equivalent load action point) of the aircraft landing gear 9 in real time, and the position changes with the retraction and lowering. The function of the hydraulic loading cylinder 5 is to apply an equivalent aerodynamic load to the aircraft landing gear load action point.

[0024] 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.

[0025] The hydraulic loading cylinder 5 is installed 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 .

[0026] 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 a cylinder self-balancing mechanism 10 .

[0027] The cylinder self-balancing structure 10 uses a cylindrical helical compression spring to balance the weight of the hydraulic loading cylinder 5. The length of the compression spring is adjusted to make the elastic force equal to the gravity of the cylinder, thereby achieving self-balancing.

[0028] In a specific embodiment, the connecting member 6 is made of 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 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.

[0029] The force sensor 7 is installed on the connecting member 6 to detect the magnitude of the loading force output by the hydraulic loading cylinder 5 .

[0030] The angular displacement sensor 8 is mounted on the fixed support 2 to detect the swing angle of the crank 12 .

[0031] The crank 12 and the rocker arm 13 are respectively hinged to the fixed support 2 and the connecting rod 11 through hinge mechanisms.

[0032] 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 on 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.

[0033] Specifically, the transmission shaft 15 and the support arm 14 are fixed via a flat key 20 .

[0034] The gearbox 4 includes an output gear 41, and the output gear 41 is fixedly connected to the sleeve 16 for fixedly connecting 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. In this way, the rotation angle provided by the motor 3 can be converted into the required rotation angle and transmitted to the parallel four-bar linkage 1 through the gearbox 4, and the rotation angle is obtained by measuring the output gear 41 by the angular displacement sensor 8. Then, the motion conversion is realized by the crank 12 of the parallel four-bar linkage 1 so that the hydraulic loading cylinder 5 follows the center of gravity (equivalent load application point) of the aircraft landing gear 9. The control strategy is to obtain the corresponding relationship between the displacement of the piston rod of the actuator of the aircraft landing gear 9 and the swing angle of the landing gear, as well as the relationship between the motor angle and the angle of the crank of the quadrilateral linkage mechanism, and convert the displacement measurement result of the piston rod of the actuator of the aircraft landing gear into the input of the crank angle control of the parallel four-bar linkage mechanism, and use the crank swing angle (equipped with an angular displacement sensor and a test channel) measurement result as the feedback quantity to control the motor angle to achieve the closed-loop control of the equivalent load application point following. The limit position of the load application point is at the fully retracted and fully lowered position of the aircraft landing gear 9. The stroke of the parallel four-bar linkage mechanism 1 needs to meet the requirements of the limit position. While achieving the load application point following, by controlling the working pressure of the hydraulic loading cylinder 5, a simulated pneumatic load is applied to the aircraft landing gear 9, and the force sensor 7 is used to measure the magnitude of the loading force. The measured value of the force sensor 7 is used as the control feedback quantity to achieve the closed-loop control of the pneumatic load.

[0035] 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 by screws 18 .

[0036] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0037] In addition, it should be noted that the scope of the methods and systems in the embodiments of the present invention is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved. For example, the described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. In addition, features described with reference to certain examples may be combined in other examples.

[0038] The embodiments of the present invention are described above, but the present invention is not limited to the above-mentioned specific implementation modes. The above-mentioned specific implementation modes 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 purpose of the present invention and the claims, all of which are within the protection of 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 mechanism comprises a connecting rod, a crank with one end hinged to the connecting rod, and a swing rod with one end hinged to the connecting rod, the crank and the swing rod are arranged in parallel and spaced apart, and the other ends of the crank and the swing rod 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 piece; The force sensor is mounted on the connecting piece to detect the magnitude of the loading force output by the hydraulic loading cylinder; The angular displacement sensor is mounted on the fixed support to detect the swing angle of the crank.

2. The aircraft landing gear aerodynamic load simulation loading device according to claim 1, characterized in that: 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.

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 cylinder is hinged on the connecting rod, and the head end is arranged on the connecting rod through a 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 respectively hinged to the fixed support and the connecting rod 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 comprises an output gear, and the output gear 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 also 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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