A hydraulic system for a landing gear tire loading simulation test of an aircraft on board

Abstract

The application discloses a kind of vehicle-mounted aircraft landing gear tire loading simulation test hydraulic systems, including hydraulic oil source module, servo loading module, attitude control module and brake module;Wherein attitude control module includes lateral inclination module, vertical module, lateral movement module, the main oil way of hydraulic oil source module is divided into two roads and enters servo loading module and attitude control module respectively, each module is connected with corresponding oil cylinder by element, and each module is simulated to the different control effect of aircraft tire by each oil cylinder action, to complete corresponding test.The application can fully meet the requirements of vehicle-mounted aircraft landing gear tire loading simulation test hydraulic systems of sliding test, falling experiment and obstacle test, the application is good in universality, can simulate the lateral inclination angle range of landing gear tire under different working conditions, lateral deflection angle range, vertical loading formation, lateral adjustment stroke, detect the reliability of aircraft landing gear tire under different working conditions.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic technology, specifically a hydraulic system for simulating tire loading on vehicle-mounted aircraft landing gear. Background Technology

[0002] With the rapid development of the national economy, the annual growth rate of domestic airport traffic volume has increased rapidly, and the civil aviation industry has achieved unprecedented development. People are paying more and more attention to aircraft safety. The aircraft landing gear is an important load-bearing and controllable component of an aircraft. Landing gear tires play an extremely important role in the safe take-off and landing of aircraft. Ground testing of landing gear tires is the last line of defense for aircraft safety. However, at present, there are few test benches for aircraft landing gear tires, and their functions are relatively simple, which cannot meet the needs of comprehensive testing.

[0003] To address the problems of low loading accuracy and significant influence of varying runway conditions in current aircraft landing gear tire testing, this invention researches a precise control scheme for landing gear tire loading and proposes a vehicle-mounted hydraulic system for simulating aircraft landing gear tire loading tests. Compared to other similar systems, this invention is reasonable and feasible, exhibiting a stable and accurate loading process with good linear strain response, meeting the loading requirements of structural testing. This invention has certain application value in similar tests. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a hydraulic system for simulating the loading of vehicle-mounted aircraft landing gear tires. This system fully meets the requirements of taxiing tests, landing tests, and obstacle clearance tests. The invention is highly versatile and can simulate different operating conditions to test the roll angle range, slip angle range, vertical load formation, and lateral adjustment stroke of landing gear tires, thereby detecting the reliability of aircraft landing gear tires under various operating conditions.

[0005] This invention is achieved through the following technical solution:

[0006] A hydraulic system for simulating the loading of vehicle-mounted aircraft landing gear tires includes a hydraulic oil source module, a servo loading module that meets the loading force control requirements of the loading mechanism under dynamic and static conditions, an attitude control module, and a braking module that meets the braking action requirements.

[0007] The attitude control module includes a tilt module for controlling the tilt angle of the test bench, a vertical module for controlling the vertical feed motion of the test bench, and a lateral module for controlling the lateral movement of the test bench.

[0008] The main oil circuit of the hydraulic oil source module is divided into two paths, which enter the servo loading module and the attitude control module respectively. Each module is connected to the corresponding oil cylinder through components, and each module simulates different control effects on the aircraft tires through the actions of each oil cylinder, thereby completing the corresponding test.

[0009] Furthermore, the hydraulic oil source module includes two constant pressure variable displacement piston pumps. The two constant pressure variable displacement piston pumps are started by corresponding motor I. The oil inlet of the two constant pressure variable displacement piston pumps is connected to the oil tank I through a primary filter. The oil outlet passes through a pilot-operated proportional relief valve, a secondary filter, and a check valve in sequence. The main oil circuit is divided into two paths, which enter the servo loading module and the attitude control module respectively. One oil circuit of the attitude control module enters the tilt module, the vertical module, and the lateral movement module respectively.

[0010] Furthermore, the oil tank I is equipped with a level gauge and a temperature sensor.

[0011] Furthermore, the servo loading module includes two sets of servo loading cylinders. The two oil circuits of the servo loading module pass through the pre-valve accumulator, the three-stage filter, and the servo valve respectively, and then split into two branches to enter the two chambers of the corresponding servo loading cylinders.

[0012] A balance valve I is installed on both branches. Pressure sensors are installed in both chambers of the servo loading cylinder. An accumulator I for oil replenishment is connected to both branches through a cartridge two-position four-way directional valve. The accumulator I connected to the rod chamber of the servo loading cylinder is connected to a proportional speed control valve that performs closed-loop control of the speed of the servo loading cylinder. The two chambers of the servo loading cylinder are connected through a solenoid switch valve I.

[0013] Furthermore, the tilting module includes two sets of tilting cylinders. The two main oil circuits of the tilting module are divided into two branches after passing through an electro-hydraulic proportional valve. Each branch passes through a balance valve II, a pressure sensor, and an accumulator before entering the corresponding two chambers of the tilting cylinder. The oil circuits of the two chambers of the tilting cylinder are also connected in parallel with a solenoid switch valve II, and the oil circuits of the two chambers of the tilting cylinder are connected through a solenoid switch valve III.

[0014] Furthermore, the vertical module includes two sets of vertical cylinders. The main oil circuit of the vertical module is divided into two oil circuits after passing through an electro-hydraulic proportional valve, which enter the corresponding two chambers of the vertical cylinder respectively.

[0015] Each oil circuit is divided into two branches. Both branches pass through balance valve III, pressure sensor, and accumulator before entering the corresponding vertical cylinder chambers. The oil circuits of the two vertical cylinder chambers are also connected in parallel with solenoid switch valve IV, and the oil circuits of the two vertical cylinder chambers are connected through solenoid switch valve V.

[0016] Furthermore, the transverse shift module includes a set of transverse shift cylinders. The main oil circuit of the transverse shift module is divided into two branches after passing through an electro-hydraulic proportional valve and connected to the two chambers of the transverse shift cylinders. A balance valve IV is provided on each of the two branches.

[0017] Furthermore, the braking module includes a vane pump, a motor II, a filter mechanism, a brake cylinder, and an oil tank II. The vane pump is driven by the motor II, and the oil from the vane pump outlet passes sequentially through a check valve, a filter mechanism, and a two-position three-way solenoid directional valve into the brake cylinder.

[0018] The braking module also includes an accumulator IV, which is controlled by an electromagnetic switch valve VI to replenish oil to the inlet of the vane pump, and is also equipped with an overflow valve.

[0019] The beneficial effects of this invention are as follows:

[0020] (1) The hydraulic system for the landing gear tire test of the aircraft includes a hydraulic oil source module, a servo loading module, an attitude control module, and a braking module. The attitude control module includes a vertical module, a roll module, and a lateral movement module. It has a wide range of applications and complete functions.

[0021] (2) This hydraulic system is equipped with three oil filters to filter the hydraulic oil. A coarse oil filter is installed at the inlet of the hydraulic pump, and two fine oil filters are installed on the high-pressure pipeline of the hydraulic oil. It is required to clean the filter element of the coarse oil filter and replace the filter element of the fine oil filter regularly to ensure that the system meets the requirements of the proportional element for the cleanliness of the oil and the accuracy of pressure and flow.

[0022] (3) This hydraulic system adopts a constant pressure variable hydraulic pump plus hydraulic accumulator oil supply scheme and technically coordinates the two to make reasonable use of system power, less heat generation of system, and the response speed can meet the requirements of loading frequency response.

[0023] In summary, this invention can provide a clean oil source that meets the requirements of servo component testing, and its output pressure and flow rate are stable and adjustable. The system can fully meet the requirements of skid test, drop test and obstacle crossing test, and has the advantages of high precision, high frequency response, good voltage stability and reasonable power utilization. Attached Figure Description

[0024] Figure 1 This is the overall hydraulic schematic diagram of the system of this invention;

[0025] Figure 2 This is a schematic diagram of the hydraulic system of the servo loading module of this invention;

[0026] Figure 3 This is a schematic diagram of the hydraulic system of the tilting module of the present invention;

[0027] Figure 4 This is a schematic diagram of the vertical module hydraulic system of the present invention;

[0028] Figure 5 This is a hydraulic schematic diagram of the transverse movement module of the present invention;

[0029] Figure 6 This is the schematic diagram of the overall hydraulic braking system of this invention;

[0030] Attached reference numerals: 1. Hydraulic oil source module; 11. Constant pressure variable piston pump; 12. Primary filter; 13. Oil tank I; 14. Pilot-operated proportional relief valve; 15. Secondary filter; 16. Check valve I; 17. Motor I; 2. Servo loading module; 20. Pressure sensor I; 21. Servo loading cylinder; 22. Pre-valve accumulator; 23. Tertiary filter; 24. Servo valve; 25. Balance valve I; 26. Two-position four-way directional valve; 27. Accumulator I; 28. Proportional speed control valve; 29. ​​Solenoid switch valve I; 3. Tilt module; 31. Tilt cylinder; 32. Electro-hydraulic proportional valve I; 33. Balance valve II; 34. Pressure sensor II; 3 5. Accumulator II, 36. Solenoid valve II, 37. Solenoid valve III, 4. Vertical module, 41. Vertical cylinder, 42. Electro-hydraulic proportional valve II, 43. Balance valve III, 44. Pressure sensor III, 45. Accumulator III, 46. Solenoid valve IV, 47. Solenoid valve V, 5. Lateral module, 51. Lateral cylinder, 52. Electro-hydraulic proportional valve III, 53. Balance valve IV, 6. Braking module, 61. Motor II, 62. Vane pump, 63. Check valve II, 64. Overflow valve, 65. Accumulator IV, 66. Solenoid valve VI, 67. Filter mechanism, 68. Two-position three-way solenoid directional valve, 69. Oil tank II, 7. Attitude control module. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0032] Example 1

[0033] A hydraulic system for simulating tire loading on vehicle-mounted aircraft landing gear, such as Figure 1 As shown, it includes a hydraulic oil source module 1, a servo loading module 2 that meets the loading force control requirements of the loading mechanism under dynamic and static conditions, an attitude control module 7, and a braking module 6 that meets the braking action requirements. The attitude control module 7 includes a tilt module 3 that realizes the tilt angle control of the test bench, a vertical module 4 that realizes the vertical feed motion of the test bench, and a lateral module 5 that realizes the lateral movement of the test bench.

[0034] The servo loading module 2 includes two sets of servo loading cylinders 21, the tilting module 3 includes two sets of tilting cylinders 31, the vertical module 4 includes two sets of vertical cylinders 41, the lateral movement module 5 includes one set of lateral movement cylinders 51, and the hydraulic oil source module 1 includes two constant pressure variable piston pumps 11. The oil inlet of the two constant pressure variable piston pumps 11 is connected to the oil tank I 13 through a primary filter 15, and the oil outlet passes through a pilot-operated proportional relief valve 14, a secondary filter 12, and a one-way valve I 16 in sequence. The main oil circuit is divided into two paths and enters the servo loading module 2 and the attitude control module 7.

[0035] like Figure 2 As shown, the servo loading module 2 passes sequentially through the pre-valve accumulator 22, the three-stage filter 23, the servo valve 24, and the balance valves I 25.1 and 25.2 before splitting into two paths that enter the corresponding two chambers of the servo loading cylinder 21. The two chambers of the servo loading cylinder 21 are equipped with pressure sensors I 20, and the oil lines of the two chambers are respectively connected to accumulators I 27.1 and 27.2 through insert two-position four-way directional valves 26.1 and 26.2. The rod chamber of the servo loading cylinder 21 is connected to accumulator I 27.1 and then to a proportional speed control valve 28. The two chambers of the servo loading cylinder 21 are connected through electromagnetic switch valve I 29.

[0036] like Figure 1 As shown, the attitude control module 7 enters the tilt module 3, vertical module 4, and lateral movement module 5 respectively.

[0037] like Figure 3 As shown, one of the main oil circuits of the tilting module 3 is divided into two branches after passing through the left electro-hydraulic proportional valve 32.1, which enter the corresponding two chambers of the tilting cylinder. The two branches are respectively equipped with balance valves II 33.1 and 33.2, and both enter the two chambers of the left tilting cylinder 31.1 after passing through pressure sensor II 34 and accumulator II 35. The oil circuits of the two chambers of the left tilting cylinder 31.1 are also connected in parallel with electromagnetic switch valves II 36.1 and 36.2. The oil circuits of the two chambers of the left tilting cylinder 31.1 are connected through electromagnetic switch valve III 37.

[0038] like Figure 4 As shown, the main oil circuit of vertical module 4 is divided into two oil circuits after passing through electro-hydraulic proportional valve II 42, which enter the two chambers of the corresponding vertical cylinder 41 respectively. Each oil circuit is divided into two branches, and the two branches are equipped with balance valves III 43.1 and 43.2 respectively. Both branches enter the two chambers of the corresponding vertical cylinder 41 after passing through pressure sensor III 44 and accumulator III 45. The oil circuits of the two chambers of vertical cylinder 41 are also connected in parallel with electromagnetic switch valve IV 46. The oil circuits of the two chambers of vertical cylinder 41 are connected through electromagnetic switch valve V 47.

[0039] like Figure 5 As shown, the main oil circuit of the transverse module 5 is divided into two branches after passing through the electro-hydraulic proportional valve 52 and connected to the two chambers of the transverse cylinder 51. The two branches are respectively equipped with balance valves Ⅳ 53.1 and 53.2.

[0040] like Figure 6 As shown, the braking module includes a vane pump 62, a motor II 61, an accumulator IV 65, a check valve 63, a relief valve 64, a solenoid valve VI 66, a filter mechanism 67, a two-position three-way solenoid directional valve 68, and an oil tank II 69. The vane pump 62 is driven by the motor II 61. Oil from the outlet of the vane pump 62 enters the brake cylinder 60 via the check valve 63, the filter mechanism 67, and the two-position three-way solenoid directional valve 68. The solenoid valve VI 66 controls the accumulator IV 65 to replenish oil to the inlet of the vane pump 62.

[0041] The above structure makes this application a hydraulic system with multiple functional modules, specifically divided into the following functional modules:

[0042] The hydraulic oil source module 1 adopts the form of dual constant pressure variable piston pumps 11. The constant pressure variable piston pump 11 has the advantages of energy saving, low noise, high speed, good self-priming ability, high reliability, and light weight. Combined with the pressure holding condition requirements, it can achieve zero flow pressure holding. At the same time, oil filters are set at the inlet and outlet of the constant pressure variable piston pump 11 and before the servo valve 24 to meet the requirements of the servo system for oil accuracy. The system pressure regulation adopts a pilot-operated proportional relief valve 14, which can realize high-precision system pressure control. In addition, the system oil tank I 13 is equipped with accessories such as level gauge and temperature sensor to monitor the oil source status in real time and ensure the stable operation of the system.

[0043] Servo loading module 2 needs to meet the high-precision loading force control requirements of the loading mechanism under both dynamic and static conditions, be able to reach the required speed during rapid descent, and have certain buffering and shock absorption measures when overcoming obstacles. The schematic diagram of servo loading module 2 designed based on the above requirements is shown below. Figure 2 As shown. The system uses servo valve 24 to control the loading of servo loading cylinder 21. The accumulator 22 before the valve is used to improve the response speed of the servo system and meet the dynamic response requirements. During rapid descent, accumulators I 27.1 and 27.2 are used to replenish oil to servo loading cylinder 21 during rapid descent, and the speed of servo loading cylinder 21 is controlled in a closed loop through the proportional speed control valve 28 after accumulator I 27.1. During obstacle crossing test, solenoid switch valve I 29 is turned on, servo loading cylinder 21 enters floating state, and at the same time, two-position four-way reversing valve 26.2 is opened, allowing accumulator I 27.2 to be connected to absorb the pressure shock caused by vibration.

[0044] Tilting module 3 is used to meet the tilting action requirements, realize the tilt angle control of the test bench, and withstand the pressure fluctuations caused by road impacts. The schematic diagram of tilting module 3 designed according to the above requirements is shown below. Figure 3As shown, the system uses a left tilting cylinder 31.1 and a right tilting cylinder 31.2 to achieve movement, and the left electro-hydraulic proportional valve 32.1 and the right electro-hydraulic proportional valve 32.2 to achieve position and speed control respectively. High-precision pressure sensors II 34 are installed in the rod-side and rodless sides of the left tilting cylinder 31.1 and the right tilting cylinder 31.2 respectively to monitor pressure changes. In order to prevent the left tilting cylinder 31.1 and the right tilting cylinder 31.2 from falling due to their own weight and to enhance the stability of high-speed heavy-load movement, balance valves II 33.1, 33.2 and 33.3, 33.4 are installed in front of the left tilting cylinder 31.1 and the right tilting cylinder 31.2 respectively. The side tilting cylinder can be followed by the combined action of electromagnetic switch valves II 36.1, 36.2 and electromagnetic switch valve III 37.

[0045] Vertical module 4 is used to meet the vertical motion requirements, realize the vertical working motion of the test bench, and withstand the pressure fluctuations caused by road impacts. The schematic diagram of vertical module 4 designed according to the above requirements is shown below. Figure 4 As shown, the system uses two sets of vertical cylinders 41 to achieve movement, and an electro-hydraulic proportional valve II 42 to achieve position and speed control. High-precision pressure sensors III 44 are installed in the rod-side and rodless-side chambers of the vertical cylinders 41 to monitor pressure changes. To prevent the vertical cylinders 41 from falling due to their own weight and to enhance the stability of high-speed, heavy-load movement, upper balance valve III 43.1 and lower balance valve III 43.2 are installed in front of the vertical cylinders 41. The cylinders can be followed by the combined action of electromagnetic switch valves IV 46 and V 47.

[0046] The transverse module 5 is used to meet the transverse movement requirements and realize the transverse movement of the test bench. The schematic diagram of the transverse module 5 designed according to the above requirements is shown below. Figure 5 As shown. The system uses a transverse cylinder 51 to achieve the action, and uses an electro-hydraulic proportional valve Ⅲ 52 to achieve position and speed control. In order to enhance the stability of high-speed heavy-load motion, a two-way balance valve Ⅳ 53 is installed in front of the transverse cylinder 51.

[0047] The braking module is used to meet the braking requirements and drive the braking mechanism to perform the braking action. The vane pump 62 of the braking module is driven by motor II 61. The oil from the outlet of vane pump 62 enters the brake cylinder 60 through one-way valve 63, filter mechanism 67, and two-position three-way solenoid directional valve 68. When the test bench performs braking, solenoid switch valve VI 66 controls accumulator IV 65 to replenish oil to the inlet of vane pump 62. The output flow of vane pump 62 controls the extension of brake cylinder 60, which drives the braking mechanism to perform braking.

[0048] The following describes the application of the hydraulic system in the simulation test of tire loading on vehicle-mounted aircraft landing gear.

[0049] The taxiing test process is as follows: The vehicle-mounted test bench stops at the starting point of the test track. Motor I17 starts running, and the two constant-pressure variable displacement plunger pumps 11 work together. The pump outlet flow is regulated by the pilot-operated proportional relief valve 14, then flows through the secondary filter 12 and the one-way valve I16. One of the main oil lines enters the servo loading module 2. The servo valve 24 is in the left position. The oil flows through the upper balance valve I25.1 and then enters the rodless chamber of the servo loading cylinder 21. The servo valve 24 controls the operation of the servo loading cylinder 21. The upper balance valve I25.1 and the lower balance valve I25.2 are interlocked to prevent the servo loading cylinder 21 from moving due to its own weight, ensuring that it can withstand the load of its simulated own weight under different working conditions. The servo loading module 2 needs to be in a working state throughout the taxiing test.

[0050] Another path of the main oil circuit enters the attitude control module 7. In the tilt module 3, the left electro-hydraulic proportional valve I 32.1 and the right electro-hydraulic proportional valve I 32.2 are in the left position and have the same opening. After passing through the left electro-hydraulic proportional valve I 32.1 and the right electro-hydraulic proportional valve I 32.2, the oil enters the rodless chamber of the left tilt cylinder 31.1 and the right tilt cylinder 31.2. The balance valves II 33.1, 33.2 and 33.3, 33.4 are interlocked to prevent the tilt cylinder 31 from moving due to its own weight, ensuring that the extension length of the two cylinders is the same and that the wheel is vertical and does not tilt.

[0051] When the electro-hydraulic proportional valve 42 of the vertical module 4 is in the left position, the oil enters the rodless chamber of the vertical cylinder 41 through the upper balance valve III 43.1, controlling the vertical cylinder 41 to extend until the wheel touches the ground. The upper balance valve III 43.1 and the lower balance valve III 43.2 are interlocked to prevent the vertical cylinder 41 from moving due to its own weight. When the electro-hydraulic proportional valve 52 of the transverse module 5 is in the left position, the oil flows through the left balance valve IV 53.1 and enters the rodless chamber of the transverse cylinder 51 to extend. The left balance valve IV 53.1 and the right balance valve IV 53.2 are interlocked to prevent the transverse cylinder 51 from moving due to its own weight, so that the wheel is in the working position.

[0052] Then, the vehicle-mounted test bench accelerates to the test takeoff speed, simulating the wheels slowly lifting off the ground. The attitude control module 7 and the servo loading module 2 simultaneously change. The left electro-hydraulic proportional valve I 32.1 of the tilt module 3 operates in the right position, oil enters the rod chamber of the left tilt cylinder 31.1, and the left tilt cylinder 31.1 retracts. The right electro-hydraulic proportional valve I 32.2 operates in the left position and increases its opening, causing the left tilt cylinder 31.1 to retract and the right tilt cylinder 31.2 to extend, ensuring the wheels tilt to a horizontal position. The electro-hydraulic proportional valve II 42 of the vertical module 4 operates in the right position, oil enters the rod chamber of the vertical cylinder 41, and the vertical cylinder 41 retracts, causing the wheels to retract. Simultaneously, the electro-hydraulic proportional valve III 52 of the lateral shift module 5 operates in the right position, oil enters the rod chamber of the lateral shift cylinder 51, controlling the wheels to return to the retracted position. As the wheels slowly lift off the ground, the servo loading module 2 adjusts the opening of the servo valve 24 to control the loading force. When the wheels are fully off the ground, the servo valve 24 controls the minimum opening, resulting in the minimum loading force. Or, when the vehicle-mounted test bench accelerates to the test takeoff speed, the electromagnetic switch valve VI66 of the braking module 6 controls the accumulator IV65 to replenish oil to the inlet of the vane pump 62, the vane pump 62 outputs flow, controls the brake cylinder 60 to extend, pushes the brake mechanism to brake, so as to ensure that the wheel brake vehicle-mounted test bench is dragged and decelerated until it stops.

[0053] The landing test process is as follows: The vehicle-mounted test bench moves at a certain speed on the test runway. When it passes the starting point, it simulates an aircraft landing. The servo valve 24 of the servo loading module 2 operates in the left position, and oil enters the rodless chamber of the servo loading cylinder 21. The two-position four-way reversing valves 26.1 and 26.2 open, and the lower accumulator I 27.1 and the upper accumulator I 27.2 replenish oil to the servo loading cylinder 21. The speed of the servo loading cylinder 21 is controlled in a closed loop by the proportional speed control valve 28 after the lower accumulator I 27.1 to ensure that the servo loading module 2 works in time when the simulated landing wheel lands. At the same time, the attitude control module 7 changes the tilt module 3. The left electro-hydraulic proportional valve I 32.1 and the right electro-hydraulic proportional valve I 32.2 are in the left position and open at the same degree. Oil enters the rodless chamber of the left tilt cylinder 31.1 and the right tilt cylinder 31.2 after passing through the left electro-hydraulic proportional valve I 32.1 and the right electro-hydraulic proportional valve I 32.2, ensuring that the extension length of the two cylinders is the same and the landing wheel is vertical and does not tilt.

[0054] Vertical module 4's electro-hydraulic proportional valve 42 operates in the left position, and hydraulic fluid enters the rodless chamber of vertical cylinder 41 through upper balance valve III 43.1, controlling the vertical cylinder 41 to extend until the wheel touches the ground. Lateral module 5's electro-hydraulic proportional valve 52 operates in the left position, and hydraulic fluid flows through left balance valve IV 53.1 and then enters the rodless chamber of lateral cylinder 51 to extend, placing the wheel in the working position. Upon ground contact, servo loading module 2 bears the load on the wheel. Finally, braking module 6's electromagnetic switch valve VI 66 controls accumulator IV 65 to replenish oil to the inlet of vane pump 62. Vane pump 62 outputs flow, controlling brake cylinder 60 to extend and push the braking mechanism to apply the brakes, ensuring the wheel braking vehicle test bench is towed and decelerated until it stops.

[0055] The obstacle crossing test process is as follows: The vehicle-mounted test bench stops at the starting point of the test track. Motor I17 starts running, and the two constant-pressure variable displacement piston pumps 11 work together. The pump outlet flow is regulated by the pilot-operated proportional relief valve 14, then flows through the secondary filter 12 and the one-way valve I16. One of the main oil lines enters the servo loading module 2. The servo valve 24 is in the left position. The oil flows through the upper balance valve I25.1 and then enters the rodless chamber of the servo loading cylinder 21. The servo valve 24 controls the operation of the servo loading cylinder 21 to ensure that it can withstand the load of its own weight under different working conditions. The servo loading module 2 needs to be in a working state at all times during the skid test. Another path from the main oil circuit enters the attitude control module 7. The left and right electro-hydraulic proportional valves 32.1 and 32.2 of the tilt module 3 are in the left position with the same opening. Oil flows through these valves and enters the rodless chambers of the left and right tilt cylinders 31.1 and 31.2, ensuring the two cylinders have the same extension length and the wheel remains vertical without tilting. The electro-hydraulic proportional valve 42 of the vertical module 4 is in the left position. Oil flows through the upper balance valve III 43.1 into the rodless chamber of the vertical cylinder 41, controlling the vertical cylinder 41 to extend until the wheel touches the ground. The electro-hydraulic proportional valve 52 of the lateral movement module 5 is in the left position. Oil flows through the left balance valve IV 53.1 into the rodless chamber of the lateral movement cylinder 51, extending the wheel into the working position. Then, the vehicle-mounted test bench accelerates to the test speed and passes through an obstacle of a certain thickness. The side end face of the plate is perpendicular to the direction of the wheel's movement. The solenoid valve I 29 of the servo loading module 2 is activated, and the two chambers of the servo loading cylinder 21 are connected to the hydraulic fluid, causing the servo loading cylinder 21 to enter a floating state. At the same time, the two-position four-way reversing valve 26.2 opens, allowing the accumulator I 27.2 to connect and absorb the pressure impact caused by vibration. The left and right solenoid valves III 37.1 and III 37.2 of the tilt module 3 are opened, and the two chambers of the left tilt cylinder 31.1 and right tilt cylinder 31.2 are connected to the hydraulic fluid, causing the left tilt cylinder 31.1 and right tilt cylinder 31.2 to float. At the same time, solenoid valves 36.1, 36.2, 36.3, and 36.4 are opened, causing the tilt cylinders 31.1 and 31.2 to move accordingly. The solenoid valve 47 of the vertical module 4 is opened, and the two chambers of the vertical cylinder 41 are connected to the hydraulic fluid, causing the vertical cylinder 41 to float. At the same time, solenoid valve 46 is opened, causing the vertical cylinder 41 to move accordingly. When the wheels clear the obstacle, the servo loading module 2's solenoid valve 29 closes, the two-position four-way directional valve 26.2 closes, the tilt module 3's solenoid valves 37.1 and 37.2 close, and solenoid valves II 36.1, 36.2, 36.3, and 36.4 close. The vertical module 4's solenoid valve V47 closes, and solenoid valve IV46 closes, returning the system to its starting state. Finally, the braking module 6's solenoid valve VI66 controls the accumulator IV65 to replenish oil to the inlet of the vane pump 62. The vane pump 62 outputs flow, controlling the brake cylinder 60 to extend and push the braking mechanism to apply the brakes, ensuring that the wheel braking vehicle test bench is towed and decelerated until it stops.

[0056] The foregoing has shown and described the main features, basic principles, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention based on actual circumstances without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A hydraulic system for simulating tire loading on vehicle-mounted aircraft landing gear, characterized in that: It includes a hydraulic oil source module (1), a servo loading module (2) that meets the loading force control requirements of the loading mechanism under dynamic and static conditions, an attitude control module (7), and a braking module (6) that meets the braking action requirements. The attitude control module (7) includes a tilt module (3) for controlling the tilt angle of the test bench, a vertical module (4) for controlling the vertical feed motion of the test bench, and a lateral module (5) for controlling the lateral movement of the test bench. The tilt module (3) includes two sets of tilt cylinders (31). The two main oil circuits of the tilt module (3) are divided into two branches after passing through electro-hydraulic proportional valve I (32). The two branches pass through balance valve II (33), pressure sensor II (34), and accumulator II (35) before entering the two chambers of the corresponding tilt cylinder (31). The oil circuits of the two chambers of the tilt cylinder (31) are also connected in parallel with electromagnetic switch valve II (36), and the oil circuits of the two chambers of the tilt cylinder (31) are connected through electromagnetic switch valve III (37). The vertical module (4) includes two sets of vertical cylinders. (41) The main oil circuit of the vertical module (4) is divided into two oil circuits after passing through the electro-hydraulic proportional valve II (42), which enter the two chambers of the corresponding vertical cylinder (41) respectively; each oil circuit is divided into two branches, and the two branches are connected to the two chambers of the corresponding vertical cylinder (41) after passing through the balance valve III (43), the pressure sensor III (44), and the accumulator III (45). The oil circuits of the two chambers of the vertical cylinder (41) are also connected in parallel with the electromagnetic switch valve IV (46), and the oil circuits of the two chambers of the vertical cylinder (41) are connected through the electromagnetic switch valve V (47); the transverse module (5) includes a set of transverse cylinders (51). The main oil circuit of the transverse module (5) is divided into two branches after passing through the electro-hydraulic proportional valve III (52), which are connected to the two chambers of the transverse cylinder (51). The two branches are equipped with the balance valve IV (53); The main oil circuit of the hydraulic oil source module (1) is divided into two paths, which enter the servo loading module (2) and the attitude control module (7) respectively. Each module is connected to the corresponding oil cylinder through components, and each module simulates different control effects on the aircraft tires through the action of each oil cylinder, thereby completing the corresponding test.

2. The hydraulic system for simulating tire loading on vehicle-mounted aircraft landing gear according to claim 1, characterized in that: The hydraulic oil source module (1) includes two constant pressure variable piston pumps (11). The two constant pressure variable piston pumps (11) are started by the corresponding motor I (17). The oil inlet of the two constant pressure variable piston pumps (11) is connected to the oil tank I (13) through the first-stage filter (15). The oil outlet passes through the pilot-operated proportional relief valve (14), the second-stage filter (12), and the check valve I (16) in sequence. The main oil circuit is divided into two paths and enters the servo loading module (2) and the attitude control module (7) respectively. One oil circuit of the attitude control module (7) enters the tilt module (3), the vertical module (4), and the lateral movement module (5) respectively.

3. The hydraulic system for simulating tire loading on vehicle-mounted aircraft landing gear according to claim 2, characterized in that: The oil tank I (13) is equipped with a level gauge and a temperature sensor.

4. The hydraulic system for simulating tire loading on vehicle-mounted aircraft landing gear according to claim 1, characterized in that: The servo loading module (2) includes two sets of servo loading cylinders (21). The two oil circuits of the servo loading module (2) pass through the pre-valve accumulator (22), the three-stage filter (23), and the servo valve (24) in sequence, and then split into two branches to enter the two chambers of the corresponding servo loading cylinder (21). A balance valve I (25) is installed on both branches. A pressure sensor I (20) is installed in both chambers of the servo loading cylinder (21). An accumulator I (27) for oil replenishment is connected to both branches through a cartridge two-position four-way directional valve (26). The servo loading cylinder (21) has a proportional speed control valve (28) that performs closed-loop control of the speed of the servo loading cylinder (21) after the accumulator I connected to the rod chamber. The two chambers of the servo loading cylinder (21) are connected through an electromagnetic switch valve I (29).

5. The hydraulic system for simulating tire loading on vehicle-mounted aircraft landing gear according to claim 1, characterized in that: The braking module includes a vane pump (62), a motor II (61), a filter mechanism (67), a brake cylinder (60), and an oil tank II (69). The vane pump (62) is driven by the motor II (61). The oil from the outlet of the vane pump (62) enters the brake cylinder (60) in sequence through a one-way valve II (63), a filter mechanism (67), and a two-position three-way solenoid directional valve (68). The braking module also includes an accumulator IV (65), which is controlled by an electromagnetic switch valve VI (66) to replenish oil to the inlet of the vane pump (62), and is also equipped with an overflow valve (64).

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