Scaled model device of simple structure of strut-type landing gear and its experimental test method

Abstract

A scale model device of a simple structure of a strut-type landing gear and its experimental testing method, which relates to the field of aircraft ground dynamics test design. The present invention solves the problem that the existing landing gear performance testing method has the following shortcomings: high testing cost, large equipment scale, high testing difficulty and complex landing gear structure, which makes it difficult to achieve large-scale promotion and use in the fields of aircraft design and aircraft ground dynamics. The upper outer cylinder wall, outer cylinder flange and lower outer cylinder wall of the present invention are coaxially connected in sequence from top to bottom, the bottom end of the strut inner cylinder is installed with a wheel assembly, one end of the auxiliary crossbeam is connected to the main crossbeam connecting piece, the longitudinal beam pin is inserted in the pin hole, one end of the main longitudinal beam is hinged to the main crossbeam connecting piece through the longitudinal beam pin, the ear piece at one end of the main longitudinal beam is hinged to one end of the longitudinal beam pin, and the longitudinal beam pin, main crossbeam, auxiliary crossbeam and the other end of the main longitudinal beam are all connected to the landing gear fixture. The present invention is used to meet the needs of a large number of experiments and tests in the fields of aircraft design and aircraft ground dynamics.

Description

Technical Field

[0001] The invention relates to the field of aircraft ground dynamics test design, and in particular to a scaled model device of a simple strut-type landing gear structure and an experimental testing method thereof. Background Art

[0002] The main function of the landing gear system is to absorb and dissipate ground loads when the aircraft is parked, taking off, landing, and taxiing on the apron, preventing other structural parts of the aircraft from contacting the ground and causing damage to the aircraft structure. Traditional landing gear performance testing methods, such as landing gear drop tests, shimmy tests, retraction and extension tests, and full-aircraft ground taxi tests, involve installing newly manufactured or repaired landing gear structures with factory certificates on specific test benches for testing. However, this testing method has shortcomings such as high testing costs, large equipment scale, high testing difficulty, and complex landing gear structures, making it difficult to promote and use on a large scale in fields such as aircraft design and aircraft ground dynamics. Therefore, based on the principles of similarity and related theories of model testing, it is very necessary to establish a scaled model of a simple strut-type landing gear structure.

[0003] Because existing aircraft rely heavily on imports, the design and development of landing gear structures is relatively underdeveloped. Landing gear design is a crucial component of an aircraft's overall design, and the key lies in the design of its buffers. Currently, modern aircraft landing gear often utilizes oil-pneumatic buffers, which absorb and dissipate adverse energy during landing impact, taxiing, and takeoff through the buffers, tires, and fuselage structure. Therefore, the present invention provides a scale model device of a simple strut-type landing gear structure to address the aforementioned issues.

[0004] In summary, existing landing gear performance test methods have shortcomings such as high testing cost, large equipment scale, high test difficulty and complex landing gear structure, making it difficult to achieve large-scale promotion and use in fields such as aircraft design and aircraft ground dynamics. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems of existing landing gear performance testing methods such as high testing cost, large equipment scale, great testing difficulty and complex landing gear structure, which make it difficult to promote and use them on a large scale in fields such as aircraft design and aircraft ground dynamics, and to provide a scale model device of a simple structure of a strut-type landing gear and a test method thereof.

[0006] The technical solution of the present invention is:

[0007] A scale model device of a simple structure of a strut-type landing gear, comprising a main buffer strut, a connecting rod and two wheel assembly assemblies, wherein the main buffer strut comprises an upper outer tube wall 6, an outer tube flange 10, a lower outer tube wall 11 and a strut inner tube 13, wherein the upper outer tube wall 6 and the lower outer tube wall 11 are both cylindrical structures, and the upper outer tube wall 6, the outer tube flange 10 and the lower outer tube wall 11 are coaxially connected in sequence from top to bottom, an upper air cavity 25 is provided inside the upper outer tube wall 6, a lower oil cavity 24 is provided inside the lower outer tube wall 11, and the center of the lower outer tube wall 11 is provided. A spacer is coaxially arranged, and the top of the spacer is connected to the outer tube flange 10. The lower oil chamber 24 is divided by the spacer into an intermediate oil chamber and an outer oil chamber arranged coaxially inside and outside. An end plate with a central oil hole is provided at the bottom of the spacer, and a circular ring groove is formed between the end plate and the inner wall of the lower outer tube wall 11. The top of the support inner tube 13 is vertically inserted into the circular ring groove of the lower outer tube wall 11 from bottom to top. The support inner tube 13 and the inner wall of the lower outer tube wall 11 and the cylindrical surface of the end plate can be slidably sealed. The support inner tube 13 is provided with a hole that can be opened and closed in the lower outer tube wall. A variable-section oil needle 26 with a decreasing outer diameter from bottom to top moves up and down in the central oil hole of the middle oil chamber of the lower oil chamber 24 of the cylinder wall 11. Two coaxially arranged wheel assemblies are installed on both sides of the bottom end of the pillar inner cylinder 13. The connecting rod includes a longitudinal beam pin 2, a main crossbeam 3, an auxiliary crossbeam 4, a main longitudinal beam 5 and a main crossbeam connecting piece 18. A crossbeam assembly through hole is radially processed on the upper side wall of the outer cylinder wall 6. The outer diameter of the longitudinal beam pin 2 is consistent with the inner diameter of the crossbeam assembly through hole. One end of the auxiliary crossbeam 4 is inserted into the crossbeam assembly through hole. The main longitudinal beam 5 is hinged to the main crossbeam connector 18 through the longitudinal beam pin 2, and the ear at one end of the main longitudinal beam 5 is hinged to one end of the longitudinal beam pin 2. The other ends of the longitudinal beam pin 2, main crossbeam 3, auxiliary crossbeam 4 and main longitudinal beam 5 in the connecting rod are all connected to the landing gear fixture. By changing the position of the landing gear fixture, the simulation of different pitch angles, roll angles and offset angles of the landing gear can be achieved.

[0008] Furthermore, an oil hole for connecting the central oil chamber and the peripheral oil chamber is processed on the side wall of the partition.

[0009] Furthermore, a chamber through hole for connecting the upper air chamber 25 and the peripheral oil chamber is processed on the outer cylinder flange 10 .

[0010] Furthermore, the main buffer pillar also includes a guide sleeve flange seat 12, which is sleeved on the outside of the pillar inner tube 13, and the guide sleeve flange seat 12 is coaxially installed at the bottom end of the lower outer tube wall 11, and a sealing rubber gasket is arranged between the guide sleeve flange seat 12 and the lower outer tube wall 11.

[0011] Furthermore, the connecting rod also includes an upper resistance strut 7, a lower resistance strut 8, a lower resistance strut connecting member 19 and an upper torque arm connecting member 20. The lower resistance strut connecting member 19 is installed on the middle side wall of the lower outer cylinder wall 11, and the upper torque arm connecting member 20 is installed on the middle side wall of the guide sleeve flange seat 12. The ear pieces at both ends of the upper resistance strut 7 are hinged to the hanging holes of the main beam 3 and the upper end of the lower resistance strut 8 respectively, and the lower end of the lower resistance strut 8 is hinged to the upper torque arm connecting member 20. A cylindrical connecting rod is integrally formed on the middle side wall of the lower resistance strut 8, and the connecting rod is hinged to the lower resistance strut connecting member 19.

[0012] Furthermore, the connecting rod also includes a retractable side support 9, and both ends of the retractable side support 9 are hinged to the connecting rods of the main longitudinal beam 5 and the lower resistance support 8 respectively.

[0013] Furthermore, the connecting rod also includes an upper torque arm 14, a lower resistance arm 15 and a lower resistance arm connecting member 23. The lower resistance arm connecting member 23 is installed on the lower side wall of the pillar inner tube 13. The upper torque arm 14 is an I-shaped structure, and the lower resistance arm 15 is an inverted Y-shaped structure. The two ends of the upper torque arm 14 are respectively hinged to the upper torque arm connecting member 20 and the upper end of the lower resistance arm 15, and the lower end of the lower resistance arm 15 is hinged to the lower resistance arm connecting member 23.

[0014] Furthermore, the main buffer pillar also includes an outer tube inflation pressure relief part 1, which is a hemispherical structure. The outer tube inflation pressure relief part 1 is installed at the top of the upper outer tube wall 6. The outer tube inflation pressure relief part 1 is processed with an inflation pressure relief port for connecting the upper air cavity 25 with the external environment.

[0015] Furthermore, each wheel assembly includes a wheel hub 16, a rubber tire 17, an axle 21 and a wheel disc 22. Two coaxially arranged axial holes are processed on both sides of the lower resistance arm connecting piece 23, and a wheel axle 21 is inserted into each axial hole. The other end of the wheel axle 21 is fitted with a wheel disc 22. The inner side of the wheel hub 16 is connected to the wheel disc 22, and the rubber tire 17 is fitted on the wheel hub 16. The wheel hub 16 is connected to the rubber tire 17 by bolts distributed at equal intervals.

[0016] A test method for a scaled model device of a simplified strut-type landing gear structure based on the ninth embodiment is implemented by the following steps:

[0017] Step 1: Installation of landing gear:

[0018] A scale model of a simple strut-type landing gear structure is mounted on a gondola system 30 of a comprehensive loading test apparatus for aircraft landing gear systems in multiple motion states using a landing gear fixture assembly. The main crossbeam 3, auxiliary crossbeam 4, and main longitudinal beam 5 are mounted on the lower surface of the gondola system 30 using a resistance strut fixture 39, a shock strut end fixture 40, and a side strut fixture 41, respectively.

[0019] Step 2: Adjustment of landing gear pitch angles:

[0020] The shock strut end fixture 40 is fixed, the resistance strut fixture 39 is replaced with a fixture structure 42 with a certain bending angle, and the side strut fixture 41 is adjusted to move in the forward direction of the landing gear, thereby driving the upper resistance strut 7 and the lower resistance strut 8 of the landing gear to move, thereby achieving the change of the aircraft's pitch angle; similarly, the resistance strut fixture 39 is fixed, the shock strut end fixture 40 is replaced with a fixture structure 42 with a certain bending angle, and the side strut fixture 41 is adjusted to move in the backward direction of the landing gear, thereby driving the upper resistance strut 7 and the lower resistance strut 8 of the landing gear to move, thereby achieving the change of the aircraft's pitch angle;

[0021] Step 3: Adjustment of landing gear roll angles:

[0022] Replace the side strut fixture 41 with a fixture structure 42 with a certain bending angle, adjust the resistance strut fixture 39 and the shock strut end fixture 40 to move perpendicular to the forward direction of the landing gear, thereby driving the left and right movement of the retractable side strut 9 of the landing gear, thereby achieving the change of the aircraft's roll angle;

[0023] Step 4: Adjustment of landing gear yaw angles:

[0024] The resistance strut clamp 39, the shock absorber strut end clamp 40 and the side strut clamp 41 are respectively replaced with three rotating assembly clamps. The upper surfaces of the upper fixed seats 43 of the three rotating assembly clamps are all connected to the lower surface of the basket system 30, and the lower fixed rails 44 of the three rotating assembly clamps are respectively connected to the main crossbeam 3, the auxiliary crossbeam 4 or the main longitudinal beam 5. During adjustment, the angle between the upper fixed seat 43 and the lower fixed rail 44 is rotated by rotating the steel ball 45, so as to realize the horizontal rotation of the landing gear to simulate the adjustment of different yaw angles of the landing gear.

[0025] Compared with the prior art, the present invention has the following effects:

[0026] 1. The present invention provides a flexible and feasible test loading device for landing gear drop shock tests and aircraft ground dynamics tests. It has the advantages of small test scale, simple structure and low cost investment, which facilitates the subsequent repetition, supplementation and improvement through more detailed theoretical modeling and simulation analysis.

[0027] 2. The entire landing gear structure of the present invention is made of GR steel material, and the forging technology can ensure the overall strength of the structure and the resistance to cold and hot fatigue.

[0028] 3. One end of the longitudinal beam pin 2, main crossbeam 3, auxiliary crossbeam 4, and main longitudinal beam 5 in the connecting rod of the present invention are all connected to the landing gear fixture. By changing the position of the fixture, the simulation of different pitch angles, roll angles, and yaw angles of the landing gear can be achieved;

[0029] 4. The upper outer tube wall 6 of the present invention is provided with an air filling valve, an oil filling valve and a simple limiter with good sealing performance, which facilitates the filling process of the filler in the strut and simplifies the transportation, installation, disassembly, replacement and maintenance of the landing gear;

[0030] 5. A scaled model of the simplified landing gear structure of the present invention, wherein the upper resistance strut 7 and the lower resistance strut 8 can reduce the bending effect of the buffer strut during drop shock tests at different pitch angles of the landing gear;

[0031] 6. The lower resistance arm connector 23 of the present invention is connected to the strut inner tube 13 and the wheel axle 21, providing not only fixed support but also lateral support for the wheelset, preventing lateral stability during landing of the landing gear with initial tire rotation speed;

[0032] 7. The tire 17 of the present invention is fixed by the wheel disc 22 and the wheel hub 16. The bolts distributed at equal intervals on the wheel hub can not only play a good fixing role, but also make the tire bear the force evenly, thereby improving the reliability of the test.

[0033] 8. The present invention has a simple structure and is easy to disassemble, and is suitable for indoor loading tests of landing gear structures of general aircraft, civil airliners, military aircraft, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of the overall structure of a scaled-down model device of a simple strut-type landing gear structure of the present invention;

[0035] Figure 2 This is a schematic diagram of the main support and axle structure of the support type buffer of the present invention;

[0036] Figure 3 is a schematic structural diagram of a landing gear resistance strut of the present invention;

[0037] Figure 4 is a schematic cross-sectional view of a buffer system of a strut-type landing gear of the present invention;

[0038] Figure 5 2. It is a schematic structural diagram of a comprehensive loading test device for an aircraft landing gear system under multiple motion states in a tenth specific embodiment of the present invention;

[0039] Figure 6 is a structural schematic diagram of a landing gear clamp assembly in a tenth specific embodiment of the present invention;

[0040] Figure 7 1 is a schematic structural diagram of a clamp structure 42 with a certain bending angle in a tenth embodiment of the present invention;

[0041] Figure 81 is a schematic structural diagram of a rotating assembly fixture structure in a tenth embodiment of the present invention;

[0042] Figure 9 It is a schematic diagram of the installation of a scaled model device of a simple strut-type landing gear structure in a tenth specific embodiment of the present invention.

[0043] In the figure: outer cylinder inflation pressure relief member 1; longitudinal beam pin 2; main crossbeam 3; auxiliary crossbeam 4; main longitudinal beam 5; upper outer cylinder wall 6; upper resistance strut 7; lower resistance strut 8; retractable side strut 9; outer cylinder flange 10; lower outer cylinder wall 11; guide sleeve flange seat 12; strut inner cylinder 13; upper torque arm 14; lower resistance arm 15; wheel hub 16; rubber tire 17; main crossbeam connector 18; lower resistance strut connector 19; upper torque arm connector 20; wheel axle 21; wheel disc 22; lower resistance arm connector 23; Lower oil chamber 24; upper air chamber 25; oil needle 26; double hydraulic cylinder 27; lifting mechanism 28; sliding beam 29; hanging basket system 30; embedded table 31; three-axis force sensor 32; impact platform base plate 33; workbench 34; upper crossbeam 35; column 36; sliding beam auxiliary plate 37; flywheel table 38; resistance strut fixture 39; shock absorber strut end fixture 40; side strut fixture 41; fixture structure with a certain bending angle 42; upper fixed seat 43; lower fixed rail 44; rotating steel ball 45. DETAILED DESCRIPTION

[0044] Specific implementation method 1: Combination Figures 1 to 4The present embodiment is described. A scale model device of a simple structure of a strut-type landing gear of the present embodiment includes a main buffer strut, a connecting rod and two wheel assembly assemblies. The main buffer strut includes an upper outer tube wall 6, an outer tube flange 10, a lower outer tube wall 11 and a strut inner tube 13. The upper outer tube wall 6 and the lower outer tube wall 11 are both cylindrical structures. The upper outer tube wall 6, the outer tube flange 10 and the lower outer tube wall 11 are coaxially connected from top to bottom. The upper outer tube wall 6 is provided with an upper air cavity 25 inside, and the lower outer tube wall 11 is provided with a lower oil cavity 24 inside. , a spacer is coaxially arranged at the center of the lower outer cylinder wall 11, and the top of the spacer is connected to the outer cylinder flange 10. The lower oil chamber 24 is divided by the spacer into an intermediate oil chamber and a peripheral oil chamber arranged coaxially inside and outside. An end plate with a central oil hole is provided at the bottom of the spacer, and a circular ring groove is formed between the end plate and the inner wall of the lower outer cylinder wall 11. The top of the support inner cylinder 13 is vertically inserted into the circular ring groove of the lower outer cylinder wall 11 from bottom to top, and the support inner cylinder 13 and the inner wall of the lower outer cylinder wall 11 and the cylindrical surface of the end plate can be slidably sealed. The inside of the support inner cylinder 13 A variable-section oil needle 26 with decreasing outer diameters from bottom to top is provided, which can move up and down in the central oil hole of the middle oil chamber of the lower oil cavity 24 of the lower outer cylinder wall 11. Two coaxially arranged wheel assemblies are respectively installed on both sides of the bottom end of the pillar inner cylinder 13. The connecting rods include a longitudinal beam pin 2, a main crossbeam 3, an auxiliary crossbeam 4, a main longitudinal beam 5 and a main crossbeam connector 18. A crossbeam assembly through hole is radially processed on the upper side wall of the outer cylinder wall 6. The outer diameter of the longitudinal beam pin 2 is consistent with the inner diameter of the crossbeam assembly through hole. One end of the auxiliary crossbeam 4 is inserted in the crossbeam. The beam is assembled in the through hole and connected to the main crossbeam connector 18 on the other side. A pin hole is processed on the ear of the main crossbeam connector 18, and the longitudinal beam pin 2 is inserted into the pin hole. One end of the main longitudinal beam 5 is hinged to the main crossbeam connector 18 through the longitudinal beam pin 2, and the ear at one end of the main longitudinal beam 5 is hinged to one end of the longitudinal beam pin 2. The other end of the longitudinal beam pin 2, main crossbeam 3, auxiliary crossbeam 4, and main longitudinal beam 5 in the connecting rod are all connected to the landing gear fixture. By changing the position of the landing gear fixture, the simulation of different pitch angles, roll angles and offset angles of the landing gear can be achieved.

[0045] In this embodiment, the outer diameter of the longitudinal beam pin 2 is consistent with the inner diameter of the pin hole of the main longitudinal beam connecting member 18 on the auxiliary crossbeam 4. Its left end is connected to the landing gear fixture, and its right end is connected to the main longitudinal beam 5, playing the role of connecting the auxiliary crossbeam 4 and the main longitudinal beam 5; the left and right ends of the main crossbeam 3 are respectively connected to the landing gear fixture and the auxiliary longitudinal beam 2, and its lower part is connected to the upper resistance support 7; the auxiliary crossbeam 4 serves as an intermediate structure connecting the outer tube wall 6 and the main crossbeam 3. Its outer diameter is consistent with the inner diameter of the crossbeam assembly through hole on the outer tube wall 6, and its other end is connected to the landing gear fixture;

[0046] Specific implementation method 2: Combination Figure 4Regarding this embodiment, the sidewalls of the separator are machined with oil holes connecting the central oil chamber with the peripheral oil chambers. This arrangement allows for oil flow regulation between adjacent oil chambers, improving the buffer's efficiency. The remaining components and connections are identical to those in the first embodiment.

[0047] Specific implementation method three: Combination Figure 4 To explain this embodiment, the outer cylinder flange 10 is machined with a through-hole for connecting the upper air chamber 25 with the peripheral oil chamber. This arrangement positions the outer cylinder flange 10 between the upper outer cylinder wall 6 and the lower outer cylinder wall 11, separating the upper air chamber 25 from the lower oil chamber 24. The remaining components and connections are identical to those in the first or second embodiments.

[0048] Specific implementation method four: Combination Figure 1 、 Figure 2 and Figure 4 To describe this embodiment, the main buffer strut of this embodiment also includes a guide sleeve flange seat 12, which is sleeved on the outside of the strut inner tube 13, and is coaxially installed on the bottom end of the lower outer tube wall 11, and a sealing rubber gasket is provided between the guide sleeve flange seat 12 and the lower outer tube wall 11. With this arrangement, the outer diameter of the guide sleeve flange seat 12 is increased compared to the diameter of the upper air chamber 25 and the lower oil chamber 24, and its inner diameter is consistent with the strut inner tube 13, and a sealing rubber gasket is provided between the two to ensure its sealing. Other components and connection relationships are the same as those of specific embodiments one, two or three.

[0049] Specific implementation method five: Combination Figures 1 to 3 To explain this embodiment, the connecting rods of this embodiment also include an upper resistance strut 7, a lower resistance strut 8, a lower resistance strut connecting member 19, and an upper torque arm connecting member 20. The lower resistance strut connecting member 19 is installed on the middle side wall of the lower outer cylinder wall 11, and the upper torque arm connecting member 20 is installed on the middle side wall of the guide sleeve flange seat 12. The ears at both ends of the upper resistance strut 7 are respectively hinged to the hanging hole of the main crossbeam 3 and the upper end of the lower resistance strut 8. The lower end of the lower resistance strut 8 is hinged to the upper torque arm connecting member 20. A cylindrical connecting rod is integrally formed on the middle side wall of the lower resistance strut 8, and the connecting rod is hinged to the lower resistance strut connecting member 19. With this arrangement, the upper resistance strut 7, the lower resistance strut 8, and the lower outer cylinder wall 11 converge at the lower resistance strut connecting member 19 and are connected to the lower outer cylinder wall 11 to form a whole, preventing the buffer strut from bending due to impact during aircraft landing or landing gear structure drop shock testing. Other components and connection relationships are the same as those of specific embodiments one, two, three, or four.

[0050] Specific implementation method six: combination Figures 1 to 3To explain this embodiment, the connecting rods also include retractable struts 9, each hingedly connected to the connecting rods of the main longitudinal beam 5 and the lower resistance strut 8. This arrangement allows the main longitudinal beam 5 to serve as an intermediate structure between the auxiliary longitudinal beam 2 and the retractable struts 9. Its other end is connected to the landing gear fixture, while the other end of the retractable struts 9 is connected to the lower wall 11 of the outer tube to simplify the simulation of landing gear retraction and extension. The remaining components and connections are identical to those of Specific Embodiments 1, 2, 3, 4, or 5.

[0051] In this embodiment, the two ends of the retractable side strut 9 are respectively connected to the main longitudinal beam 5 and the lower resistance strut 8. Since this example focuses more on the dynamic test of the landing and taxiing process of the landing gear, it is set as a single rod. If it is necessary to conduct a retraction test of the landing gear system in the future, it can be replaced with two rods. In addition, the connection point at its lower end can be shifted from the forward direction of the landing gear structure to the rear side to disperse the force at the upper torque arm connector 20 of the guide sleeve flange seat 12.

[0052] Specific implementation method seven: combination Figure 1 and Figure 2 To describe this embodiment, the connecting rods of this embodiment also include an upper torque arm 14, a lower resistance arm 15, and a lower resistance arm connector 23. The lower resistance arm connector 23 is mounted on the lower side wall of the strut inner tube 13. The upper torque arm 14 is an I-shaped structure, and the lower resistance arm 15 is an inverted Y-shaped structure. The ends of the upper torque arm 14 are hinged to the upper torque arm connector 20 and the upper end of the lower resistance arm 15, respectively, and the lower end of the lower resistance arm 15 is hinged to the lower resistance arm connector 23. With this arrangement, the upper end of the upper torque arm 14 is connected to the lower resistance strut 8 at the upper torque arm connector 20, and its lower end is connected to the lower resistance arm 15. The lower end of the lower resistance arm 15 is connected to the lower resistance arm connector 23 to form a whole, thereby preventing rotation between the lower outer tube wall 11 of the main buffer and the strut inner tube 13 during landing gear movement. Other components and connection relationships are the same as those of the first, second, third, fourth, fifth, or sixth embodiments.

[0053] In this embodiment, a rubber pad is provided between the lower resistance strut 8 and the upper torque arm 14 to provide a cushioning and shock-absorbing effect. The upper and lower resistance struts 7 and 8 can be replaced with a rod structure directly forged integrally with the lower outer cylinder wall 11, thereby improving the structural integrity while ensuring that the buffer strut does not bend.

[0054] In this embodiment, the upper torque arm 14 is connected to the guide sleeve flange seat 12 and the lower resistance arm 15 in an I-shape, and the lower resistance arm 15 is an inverted Y-shaped structure. This combination has a simple structure and good symmetrical force bearing capacity, which can reduce the possibility of torsional damage. Its structure can be replaced by two triangular structures connected by vertices.

[0055] Specific implementation method eight: combination Figure 1 、 Figure 2 and Figure 4 To explain this embodiment, the main buffer pillar of this embodiment also includes an outer tube inflation pressure relief member 1. The outer tube inflation pressure relief member 1 is a hemispherical structure. The outer tube inflation pressure relief member 1 is installed at the top of the upper outer tube wall 6. The outer tube inflation pressure relief member 1 is processed with an inflation pressure relief port for connecting the upper air cavity 25 with the external environment. In this way, the outer tube inflation pressure relief member 1 is located at the top of the main buffer pillar and has the function of transmitting impact loads and resisting impacts. When the amount of nitrogen in the upper air cavity 25 is insufficient, it can be directly simulated by filling nitrogen through the outer tube inflation pressure relief member 1. The inflation amount needs to be determined according to the load level that needs to be borne. The other components and connection relationships are the same as those of specific embodiments one, two, three, four, five, six or seven.

[0056] Specific implementation method nine: Combination Figure 1 、 Figure 2 and Figure 4 To describe this embodiment, each wheel assembly of this embodiment includes a wheel hub 16, a rubber tire 17, an axle 21, and a wheel disc 22. Two coaxially arranged axial holes are machined on both sides of the lower resistance arm connecting member 23, and a wheel axle 21 is inserted into each axial hole. The other end of the wheel axle 21 is fitted with a wheel disc 22. The inner side of the wheel hub 16 is connected to the wheel disc 22. The rubber tire 17 is fitted onto the wheel hub 16, and the wheel hub 16 is connected to the rubber tire 17 via bolts distributed at equal intervals. With this arrangement, the outer diameter of the wheel axle 21 is consistent with the inner diameter of the axial hole on the lower resistance arm connecting member 23 and the wheel disc 22, which serves to fix and rotate the tire. The other components and connection relationships are the same as those of the specific embodiments one, two, three, four, five, six, seven, or eight.

[0057] Specific implementation method ten: Combination Figures 1 to 8 This embodiment is described as a test method for a scaled model device of a simple strut-type landing gear structure according to the ninth embodiment. The method is implemented by the following steps:

[0058] Step 1: Installation of landing gear:

[0059] A scale model of a simple strut-type landing gear structure is mounted on a gondola system 30 of a comprehensive loading test apparatus for aircraft landing gear systems in multiple motion states using a landing gear fixture assembly. The main crossbeam 3, auxiliary crossbeam 4, and main longitudinal beam 5 are mounted on the lower surface of the gondola system 30 using a resistance strut fixture 39, a shock strut end fixture 40, and a side strut fixture 41, respectively.

[0060] Step 2: Adjustment of landing gear pitch angles:

[0061] The shock strut end fixture 40 is fixed, the resistance strut fixture 39 is replaced with a fixture structure 42 with a certain bending angle, and the side strut fixture 41 is adjusted to move in the forward direction of the landing gear, thereby driving the upper resistance strut 7 and the lower resistance strut 8 of the landing gear to move, thereby achieving the change of the aircraft's pitch angle; similarly, the resistance strut fixture 39 is fixed, the shock strut end fixture 40 is replaced with a fixture structure 42 with a certain bending angle, and the side strut fixture 41 is adjusted to move in the backward direction of the landing gear, thereby driving the upper resistance strut 7 and the lower resistance strut 8 of the landing gear to move, thereby achieving the change of the aircraft's pitch angle;

[0062] Step 3: Adjustment of landing gear roll angles:

[0063] Replace the side strut fixture 41 with a fixture structure 42 with a certain bending angle, adjust the resistance strut fixture 39 and the shock strut end fixture 40 to move perpendicular to the forward direction of the landing gear, thereby driving the left and right movement of the retractable side strut 9 of the landing gear, thereby achieving the change of the aircraft's roll angle;

[0064] Step 4: Adjustment of landing gear yaw angles:

[0065] The resistance strut clamp 39, the shock absorber strut end clamp 40 and the side strut clamp 41 are respectively replaced with three rotating assembly clamps. The upper surfaces of the upper fixed seats 43 of the three rotating assembly clamps are all connected to the lower surface of the basket system 30, and the lower fixed rails 44 of the three rotating assembly clamps are respectively connected to the main crossbeam 3, the auxiliary crossbeam 4 or the main longitudinal beam 5. During adjustment, the angle between the upper fixed seat 43 and the lower fixed rail 44 is rotated by rotating the steel ball 45, so as to realize the horizontal rotation of the landing gear to simulate the adjustment of different yaw angles of the landing gear.

[0066] Combine Figure 8In this embodiment, the rotating assembly clamp includes an upper fixed seat 43, a lower fixed rail 44 and a rotating steel ball 45. The lower fixed rail 44 is a T-shaped block structure. The lower surface of the lower fixed rail 44 is processed into an arc surface. The middle part of the upper surface of the lower fixed rail 44 is integrally forged with a rotating steel ball 45. The rotating steel ball 45 is connected to the lower fixed rail 44 through a variable-section rotating body structure. The lower fixed rail 44 and the rotating steel ball 45 are integrally forged to ensure the integrity of the structure; the upper fixed seat 43 is a split structure, and the upper fixed seat 43 includes a left fixed block, a right fixed block and a plurality of connecting blocks. The left fixed block and the right fixed block are arranged side by side, and the left fixed block is detachably connected to the right fixed block through multiple connecting parts. The left fixed block and the right fixed block are both processed with grooves that match the rotating steel ball 45 and the variable-section rotating body structure. The rotating steel ball 45 is placed in the steel ball accommodating cavity formed by the combination of the left fixed block and the right fixed block. The outer surface of the rotating steel ball 45 and the inner surface of the steel ball accommodating cavity are tightly fitted, which ensures that the two can rotate relative to each other under the action of external force, and also has a locking function to ensure that the two can be relatively fixed at any position.

[0067] In addition, the lugs of the lower fixed rail 44 can also be replaced with a clamp structure 42 with a certain bending angle, thereby realizing complex motion posture simulation of a combination of pitch angle, roll angle and yaw angle.

[0068] The other components and connection relationships are the same as those in the first, second, third, fourth, fifth, sixth, seventh, eighth or ninth embodiment.

[0069] In this embodiment, the comprehensive loading test device for the aircraft landing gear system in multiple motion states includes a hydraulic mechanism, a lifting and hanging basket assembly, a multi-functional impact platform and a landing gear fixture assembly. The hydraulic mechanism includes a double hydraulic cylinder 27, a sliding beam 29, a workbench 34, an upper crossbeam 35, a sliding beam auxiliary plate 37 and four columns 36. The upper crossbeam 35, the sliding beam 29, the sliding beam auxiliary plate 37 and the workbench 34 are arranged horizontally from top to bottom. The four corners of the upper crossbeam 35 and the workbench 34 are connected by four vertically arranged columns 36 respectively. The sliding beam 29 and the sliding beam auxiliary plate 37 are slidable through the reserved through holes at the four corners. It is dynamically installed on four columns 36, and a reserved hole is set in the middle of the sliding beam auxiliary plate 37. The reserved hole can allow the landing gear system installed on the lifting and hanging basket assembly to pass smoothly. The upper surface of the upper beam 35 is installed with a vertical and symmetrically arranged double hydraulic cylinder 27. The two piston rod ends of the double hydraulic cylinder 27 pass through the upper beam 35 and are connected to the upper surface of the sliding beam 29. A lifting and hanging basket assembly is provided between the sliding beam 29 and the sliding beam auxiliary plate 37. The lifting and hanging basket assembly includes a lifting mechanism 28, a hanging basket system 30, a magnetic device, two snap locks and four sliding rails, the sliding beam 29 and the sliding beam auxiliary plate The four corners of 37 are connected by four vertically arranged sliding rails respectively. The hanging basket system 30 is located between the sliding beam 29 and the sliding beam auxiliary plate 37. The hanging basket system 30 can be slidably installed on the four sliding rails through the reserved through holes at the four corners. A landing gear clamp assembly is installed on the lower surface of the hanging basket system 30. A magnetic device is arranged in the middle of the upper surface of the hanging basket system 30. A hanging hole is reserved on the upper surface of the magnetic device. The lifting mechanism 28 is connected to the reserved hanging hole of the magnetic device. The lifting mechanism 28 is installed in the middle of the upper surface of the upper crossbeam 35. Two snap locks are installed on the hanging basket system 30. The hanging basket system 30 is connected by two Each snap lock is detachably connected to the corresponding sliding track. A multifunctional impact platform is arranged between the sliding beam auxiliary plate 37 and the workbench 34. The multifunctional impact platform includes a multifunctional impact platform base plate 33, a road surface test platform component and a flywheel test platform component. The multifunctional impact platform base plate 33 is located on the upper surface of the workbench 34. The lower surface of the multifunctional impact platform base plate 33 is provided with a slide rail. The multifunctional impact platform base plate 33 is slidably connected to the reserved slide groove on the workbench 34 through the slide rail. The upper surface of the multifunctional impact platform base plate 33 is provided with a road surface test platform component and a flywheel test platform component from left to right.

[0070] The pavement test platform assembly includes an embedded table top 31 and four three-dimensional force sensors 32. The embedded table top 31 is fixed to one end of the multi-functional impact platform base plate 33 through the three-dimensional force sensors 32 at the four corner points. A rectangular pavement structure placement groove is provided in the middle of the embedded table top 31, and a pavement structure paved with real materials is placed in the pavement structure placement groove.

[0071] The flywheel test platform assembly includes a flywheel table 38, a roller drive motor, two rollers and four three-dimensional force sensors 32. The flywheel table 38 is fixed to the other end of the multi-functional impact platform base plate 33 through the three-dimensional force sensors 32 at the four corner points. Two reserved rectangular holes are set in the middle of the flywheel table 38 according to the size and spacing of the landing gear wheel group. A roller drive motor is arranged between the flywheel table 38 and the multi-functional impact platform base plate 33. Two rollers are installed side by side on the motor shaft of the roller drive motor. The two rollers correspond one by one to the two reserved rectangular holes of the flywheel table 38, and the upper surfaces of the two rollers are flush with the upper surface of the flywheel table 38.

[0072] The landing gear fixture assembly includes a resistance strut fixture 39, a shock absorber strut end fixture 40 and a side strut fixture 41. The resistance strut fixture 39 and the shock absorber strut end fixture 40 have reserved shaft holes on their sides. A linear track is provided at the bottom of the shock absorber strut end fixture 40. The reserved shaft holes are used to connect with the landing gear system. The linear track is used to achieve sliding with the hanging basket system 30. The reserved shaft holes provided on the sides of the resistance strut fixture 39 and the shock absorber strut end fixture 40 are coaxially arranged. The axis is parallel to the center line of the lower surface of the hanging basket system 30 in the width direction. The resistance support clamp 39 and the shock-absorbing support end clamp 40 can slide forward and backward along the length direction of the lower surface of the hanging basket system 30 through the straight track set at the bottom. The side support clamp 41 is located on the side of the resistance support clamp 39 and the shock-absorbing support end clamp 40. The axis of the reserved shaft hole of the side support clamp 41 is parallel to the center line of the lower surface of the hanging basket system 30 in the length direction. The side support clamp 41 can slide left and right along the width direction of the lower surface of the hanging basket system 30 through the straight track set at the bottom.

[0073] As an embodiment of the present invention, a scaled model device of a simple strut-type landing gear structure is proposed. It can be used as a test subject, such as fatigue test and performance test (drop test, swing test) of the landing gear structure, etc. It can also be used as a loading device to test other objects such as the ground, such as road surface type selection, acquisition of internal response distribution law of road surface structure, tire-road interaction mechanism analysis, and research on friction coefficient of ice and snow road surfaces.

[0074] The basic scaling method and implementation steps of the present invention are as follows:

[0075] (1) Based on the similarity principle and relevant theories of model testing, the scale model design and calculation of the simple structure of the strut-type landing gear are carried out:

[0076] Based on the theory of similarity theorem, physical quantities such as landing gear geometry l, velocity v, density ρ, mass m, acceleration a, angular velocity ω, modulus E, time t, pressure p and load level F are selected, and the scaling relationship between prototype test and model test is established through dimensional analysis method: (geometric similarity) and (mechanical similarity); then by solving the dimensional matrix, 8 independent π terms are determined as follows:

[0077]

[0078]

[0079] Finally, assuming that the material density of the structure remains basically unchanged, the similarity constant of the test time is taken as 1, that is, under the premise of meeting the above mechanical conditions, assuming that the material density and time are not reduced in size, C ρ =C t =1; To satisfy the conditions of v = wl and w = 2πf, the speed ratio should satisfy C v =C l ; From this, we can get the similarity constants of each parameter as follows:

[0080]

[0081] Note: c F ,ct,c M 、c x They are force similarity constant, time similarity constant, mass similarity constant and displacement similarity constant respectively.

[0082] (2) As an embodiment of the present invention, taking the drop test as an example, the drop test condition design and test results collection and analysis are carried out on a scaled model of a simple landing gear structure; later, the drop test results of the scaled model can be restored to the prototype test according to the similarity principle, and verified with the help of theoretical calculation and simulation analysis methods, and finally the performance prediction and early warning of the full-scale landing gear prototype test can be achieved.

[0083] How it works

[0084] Combine Figures 1 to 4 The working principle of the scaled model device for a simplified strut-type landing gear structure described in this invention is explained: To meet the extensive testing needs in fields such as aircraft design and aircraft ground dynamics, a typical strut-type landing gear structure—a strut-type landing gear structure—was simplified and scaled based on the principle of similarity and relevant theories of model testing. Ultimately, a scaled model device for the simplified strut-type landing gear structure was developed. While ensuring geometric and mechanical similarity, the scaled design was performed on a full-scale aircraft landing gear. The reliability of the scaled model's external characteristics was verified through simulation analysis and prototype testing. This provides technical support for the analysis and prediction of dynamic loads and load responses in full-scale aircraft-ground interactions.

[0085] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A scale model device of a simple strut-type landing gear structure, characterized by: It includes a main buffer support, a connecting rod and two wheel assembly assemblies. The main buffer support includes an upper outer cylinder wall (6), an outer cylinder flange (10), a lower outer cylinder wall (11) and a support inner cylinder (13). The upper outer cylinder wall (6) and the lower outer cylinder wall (11) are both cylindrical structures. The upper outer cylinder wall (6), the outer cylinder flange (10) and the lower outer cylinder wall (11) are coaxially connected from top to bottom. An upper air cavity (25) is provided inside the upper outer cylinder wall (6), a lower oil cavity (24) is provided inside the lower outer cylinder wall (11), and a spacer is coaxially provided at the center of the lower outer cylinder wall (11). The top end is connected to the outer tube flange (10), and the lower oil chamber (24) is divided by the spacer into an intermediate oil chamber and an outer oil chamber arranged coaxially inside and outside. The bottom end of the spacer is provided with an end plate with a central oil hole, and a circular ring groove is formed between the end plate and the inner wall of the lower outer tube wall (11). The top end of the support inner tube (13) is vertically inserted into the circular ring groove of the lower outer tube wall (11) from bottom to top. The support inner tube (13) and the inner wall of the lower outer tube wall (11) and the cylindrical surface of the end plate can be slidably sealed. The support inner tube (13) is provided with a lower oil chamber (24) that can be opened in the lower outer tube wall (11). 4), a variable cross-section oil needle (26) with a decreasing outer diameter from bottom to top moves up and down in the central oil hole of the intermediate oil chamber, two coaxially arranged wheel assembly assemblies are respectively installed on both sides of the bottom end of the pillar inner tube (13), the connecting rod comprises a longitudinal beam pin (2), a main cross beam (3), an auxiliary cross beam (4), a main longitudinal beam (5) and a main cross beam connecting member (18), a cross beam assembly through hole is radially processed on the upper side wall of the outer tube wall (6), the outer diameter of the longitudinal beam pin (2) is consistent with the inner diameter of the cross beam assembly through hole, one end of the auxiliary cross beam (4) is inserted into the cross beam assembly through hole and connected to the other end. The main longitudinal beam (5) is connected to the main crossbeam connecting member (18) on the side, a pin hole is processed on the ear piece of the main crossbeam connecting member (18), and the longitudinal beam pin (2) is inserted into the pin hole. One end of the main longitudinal beam (5) is hinged to the main crossbeam connecting member (18) through the longitudinal beam pin (2), and the ear piece at one end of the main longitudinal beam (5) is hinged to one end of the longitudinal beam pin (2). The longitudinal beam pin (2), the main crossbeam (3), the auxiliary crossbeam (4), and the other end of the main longitudinal beam (5) in the connecting rod are all connected to the landing gear fixture. By changing the position of the landing gear fixture, simulation of different pitch angles, roll angles and offset angles of the landing gear can be achieved.

2. The scale model device of the simplified strut-type landing gear structure according to claim 1, characterized in that: An oil hole for connecting the central oil chamber and the peripheral oil chamber is processed on the side wall of the separator.

3. The scale model device of the simplified strut-type landing gear structure according to claim 1 or 2, characterized in that: A chamber through hole for connecting the upper air chamber (25) and the peripheral oil chamber is processed on the outer cylinder flange (10).

4. The scale model device of the simplified strut-type landing gear structure according to claim 3, characterized in that: The main buffer pillar further comprises a guide sleeve flange seat (12), which is sleeved on the outside of the pillar inner tube (13) and coaxially mounted on the bottom end of the lower outer tube wall (11). A sealing rubber gasket is provided between the guide sleeve flange seat (12) and the lower outer tube wall (11).

5. The scale model device of the simplified strut-type landing gear structure according to claim 4, characterized in that: The connecting rod also includes an upper resistance support (7), a lower resistance support (8), a lower resistance support connecting member (19) and an upper torque arm connecting member (20). The lower resistance support connecting member (19) is installed on the middle side wall of the lower outer cylinder wall (11), and the upper torque arm connecting member (20) is installed on the middle side wall of the guide sleeve flange seat (12). The ear pieces at both ends of the upper resistance support (7) are respectively hinged to the hanging hole of the main crossbeam (3) and the upper end of the lower resistance support (8), and the lower end of the lower resistance support (8) is hinged to the upper torque arm connecting member (20). A cylindrical connecting rod is integrally formed on the middle side wall of the lower resistance support (8), and the connecting rod is hinged to the lower resistance support connecting member (19).

6. The scale model device of the simplified strut-type landing gear structure according to claim 5, characterized in that: The connecting rod also includes a retractable side support (9), and both ends of the retractable side support (9) are respectively hinged to the connecting rods of the main longitudinal beam (5) and the lower resistance support (8).

7. The scale model device of the simplified strut-type landing gear structure according to claim 6, characterized in that: The connecting rod also includes an upper torque arm (14), a lower resistance arm (15) and a lower resistance arm connecting member (23). The lower resistance arm connecting member (23) is installed on the lower side wall of the pillar inner tube (13). The upper torque arm (14) is an I-shaped structure, and the lower resistance arm (15) is an inverted Y-shaped structure. The two ends of the upper torque arm (14) are respectively hinged to the upper torque arm connecting member (20) and the upper end of the lower resistance arm (15), and the lower end of the lower resistance arm (15) is hinged to the lower resistance arm connecting member (23).

8. The scale model device of the simplified strut-type landing gear structure according to claim 1 or 7, characterized in that: The main buffer support further comprises an outer cylinder inflation pressure relief member (1), which is a hemispherical structure and is mounted on the top of the upper outer cylinder wall (6). An inflation pressure relief port for connecting the upper air cavity (25) with the external environment is machined on the outer cylinder inflation pressure relief member (1).

9. The scale model device of the simplified strut-type landing gear structure according to claim 8, characterized in that: Each wheel assembly includes a wheel hub (16), a rubber tire (17), a wheel axle (21) and a wheel disc (22). Two coaxially arranged axial holes are processed on both sides of the lower resistance arm connecting member (23). A wheel axle (21) is inserted into each axial hole. The other end of the wheel axle (21) is sleeved with a wheel disc (22). The inner side of the wheel hub (16) is connected to the wheel disc (22). The rubber tire (17) is sleeved on the wheel hub (16). The wheel hub (16) is connected to the rubber tire (17) by bolts distributed at equal intervals.

10. A test method based on the scale model device of the simplified strut-type landing gear structure according to claim 9, characterized in that: The method is achieved by the following steps: Step 1: Installation of landing gear: A scale model device of a simple strut-type landing gear structure is mounted on a hanging basket system (30) of a comprehensive loading test device for an aircraft landing gear system in a multi-motion state by using a landing gear fixture assembly, and a main crossbeam (3), an auxiliary crossbeam (4) and a main longitudinal beam (5) are mounted on the lower surface of the hanging basket system (30) by using a resistance strut fixture (39), a shock absorber strut end fixture (40) and a side strut fixture (41). Step 2: Adjustment of landing gear pitch angles: The shock absorber strut end fixture (40) is fixed and does not move, the position of the resistance strut fixture (39) is moved, and the resistance strut fixture (39) and the shock absorber strut end fixture (40) are replaced with a fixture structure (42) with a certain bending angle, and the side strut fixture (41) is adjusted to move in the forward direction of the landing gear, thereby driving the upper resistance strut (7) and the lower resistance strut (8) of the landing gear to move, thereby realizing the change of the aircraft's pitch angle; similarly, the resistance strut fixture (39) is fixed and does not move, and the resistance strut fixture (39) and the shock absorber strut end fixture (40) are replaced with a fixture structure (42) with a certain bending angle, and the side strut fixture (41) is adjusted to move in the backward direction of the landing gear, thereby driving the upper resistance strut (7) and the lower resistance strut (8) of the landing gear to move, thereby realizing the change of the aircraft's pitch angle; Step 3: Adjustment of landing gear roll angles: The side strut fixture (41) is replaced with a fixture structure (42) with a certain bending angle, and the resistance strut fixture (39) and the shock absorber strut end fixture (40) are adjusted to move perpendicular to the forward direction of the landing gear, thereby driving the retractable side strut (9) of the landing gear to move left and right, thereby realizing the change of the aircraft's roll angle; Step 4: Adjustment of landing gear yaw angles: The resistance strut fixture (39), the shock-absorbing strut end fixture (40) and the side strut fixture (41) are respectively replaced with three rotating assembly fixtures. The upper surfaces of the upper fixing seats (43) of the three rotating assembly fixtures are all connected to the lower surface of the hanging basket system (30). The lower fixing rails (44) of the three rotating assembly fixtures are respectively connected to the main crossbeam (3), the auxiliary crossbeam (4) or the main longitudinal beam (5). During adjustment, the angle between the upper fixing seat (43) and the lower fixing rail (44) is rotated by rotating the steel ball (45), so that the horizontal rotation of the landing gear can be realized to simulate the adjustment of different yaw angles of the landing gear.

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