A side slip loading and rolling device and test method for an aircraft wheel fatigue test bench

Abstract

A side slip loading device and test method for an aircraft wheel fatigue test bench. The outer surface of the drum is used to simulate the aircraft runway. The rolling movement between the movable frame and the guiding frame is realized through the guiding rollers distributed between the movable frame and the guiding frame, reducing the movement resistance, overcoming the drawback of excessive resistance in the existing rail type loading that leads to loading load deviation, and improving the reliability of the test bench and the credibility of the test parameters. A simple driving device is used to realize the side slip swing of the side slip loading device of the aircraft wheel fatigue life test bench; through the angle sensor, the accuracy of the yaw angle is improved from ±1° to ±0.1°, reducing the labor intensity of workers, increasing the operation safety of the equipment, providing a reliable and convenient test device for studying aircraft wheels and tires with better performance, capable of realizing the side slip roll test and accelerated life test of all military and civil aircraft wheels under specified conditions, and having the characteristics of low experimental cost and easy implementation.

Description

Technical Field

[0001] The present invention belongs to the technical field of aircraft wheel tests, and particularly relates to a side deviation loading and rolling device for aircraft wheel fatigue tests. Background Art

[0002] Aircraft wheels are an important part of the aircraft takeoff and landing system, bearing the dynamic loads during aircraft takeoff and landing taxiing, the impact loads at the moment of landing, and the static loads when the aircraft is parked. Their performance directly affects the aircraft's taxiing performance and braking deceleration performance, and has a great impact on the safety of aircraft takeoff and landing. With the rapid development of China's aviation technology and the continuous improvement of aircraft performance, the performance requirements for aircraft wheels have been greatly improved. It is required that the wheels be light in weight, have a large load-bearing capacity, and a long service life. In particular, the service life index of carbon brake wheels has exceeded 1000 landings. The service life requirements for the wheels of some military aircraft reach 3000 landings, and those for civil aircraft reach 5000 landings. When the static strength of the wheels meets the design requirements, the life index requirement has become the main research project in wheel design. The service life of aircraft wheels is mainly affected by dynamic load fatigue damage. This requires that the strength and fatigue life tests of aircraft wheels must simulate actual working conditions and be carried out as in-plant assessment tests before being installed and used.

[0003] An aircraft wheel life test bench is a test device used to assess whether the designed life of an aircraft wheel can meet the requirements of technical specifications before the design of the aircraft wheel product is finalized. The wheel undergoes a loading and rolling test on the life test bench according to the requirements of the load spectrum, accumulates the rolling test mileage, and evaluates its life. The current national military standards, aviation standards, and enterprise standards for aircraft wheel fatigue life tests in China basically follow the fatigue life test methods of foreign military standards. For military aircraft wheels, the test methods specified in HB5651 "General Technical Conditions for Aircraft Wheels" and GJB1184A "General Specification for Aircraft Wheels and Braking Devices" are basically used to evaluate the fatigue life of the wheels; for civil aircraft wheels, the test methods specified in the Federal Aviation Administration (FAA) TSO-C135 "Wheels and Braking Devices for Transport Category Aircraft" and the Civil Aviation Administration of China's CTSO-C135 "Wheels and Braking Devices for Transport Category Aircraft" are basically used to evaluate the fatigue life of the wheels. The above standard evaluation test methods require multiple sub-samples for testing, and the test cycle is very long. It takes at least more than one year of test time to evaluate the life of each type of wheel.

[0004] In the 1990s in the United States, ARP597(C), "Supplemental Criteria for Design Durability of Civil Transport Aircraft Wheels and Brakes", specified the accelerated fatigue life test method for aircraft wheels. This method increased the yaw lateral load and added a roll resistance load on the basis of the US military standard. According to this load spectrum method, when the wheel conducts an accelerated life test, 1 landing in the field test is equivalent to the life of 5 landings in actual flight use in the field. This can greatly shorten the fatigue life test time of aircraft wheels, and the accelerated life test method is also widely used in Western developed countries. The ARP597(C) method was also used for life assessment on the domestic-made wheels of TY154 civil aircraft. According to this method, an accelerated life test bench for aircraft wheels needs to be newly built.

[0005] For the new test method, the aircraft wheels need to simulate the actual use conditions during the test to complete the accelerated life test. When the aircraft is in different working states, the force conditions of the wheels are different.

[0006] 1. When the aircraft is in a stationary state, the bearing mainly bears the static load.

[0007] 2. When the aircraft is taxiing on the ground, it mainly bears the vertical load. Due to the non - absolute flatness of the ground, the amplitude of the aircraft's up - and - down vibration is greater than the gravity of the aircraft.

[0008] 3. When landing, at the moment the wheel touches the ground, it is first mainly subjected to a huge static vertical impact load, and then the wheel accelerates at a very high acceleration to reach the same speed as the aircraft and skids on the ground. If it touches the ground with a sideslip, such as when the cross - wind is large, the wheel will be subjected to a large lateral load. When the wheel is subjected to a lateral frictional force, due to inertia, the aircraft has a tendency to tilt to one side. Therefore, 10% of the mileage of the wheel life test needs to be carried out with a side - offset loading roll life test.

[0009] Currently, the original domestic aircraft wheel fatigue life test benches were designed and manufactured according to the test methods specified in HB5651, GJB1184A, TSO - C135, and CTSO - C135. The side - offset loading roll test uses the movable loading mechanism of a yaw test bench. The yaw angle is determined by the magnitude of the test load. When the test bench yaws and swings, the factory crane is used to pull the movable loading mechanism of the test bench to move around the center of the drum in front. The operation is cumbersome, the safety and reliability are poor, and it is difficult to adjust the side - offset angle precisely.

[0010] A lateral loading device was proposed in the invention creation with the application number 201810777177.0. A roller chain is installed around the outer edge of the outer guide rail of this lateral loading device, and a driving motor is installed at the tail of the bracket. When realizing the lateral angular yaw, the driving motor is started to drive the sprocket to rotate, and the engagement between the sprocket and the roller chain is used to push the bracket to yaw. The yaw angle is visually determined by the arranged angle scale. The deficiencies of this lateral loading device are as follows: First, because the sprocket needs to engage with the roller chain, the accuracy of the deflection angle is limited by the number of links of the roller chain. Second, for the loading method of the wheels, the solution is to install a wheel support guide rail above the large bracket. The loading load direction of the wheels and the force direction of the test bench are not in the same horizontal plane. The wheel load direction is the horizontal plane where the wheel axis is located. The force on the bracket is transmitted from the wheel support guide rail to the bracket. When the wheels are subjected to resistance loading, the direction of the resistance moment is perpendicular to the horizontal plane. In this way, the resultant force forms a lever force on the wheel support guide rail, so this loading method greatly limits its loading load. Third, for this way of installing the guide rail, there is a large gap between the upper part of the guide rail and the slider. The test bench has large vibrations during the rotation of the large-mass drum and the loading of the wheel load, which will cause the wheel mounting frame to vibrate up and down. This gap is a fatal defect of this loading method. Summary of the Invention

[0011] To overcome the deficiency in the prior art that the accelerated fatigue life test of aircraft wheels cannot be carried out, the present invention proposes a side deflection loading and rolling device and a test method for an aircraft wheel fatigue test bench.

[0012] The side slip loading and rolling device of the aircraft wheel fatigue test bench includes a drum, a main shaft, a substrate assembly, a steering frame, a wheel axle, a U-shaped loading head, a guiding frame, a movable frame, a loading oil cylinder, an outer slide rail, an inner slide rail, a side slip oil cylinder, a support oil cylinder, an outer slide rail fastening screw, an inner slide rail fastening screw, a load sensor, and a vertical guiding roller. Among them: The main shaft is installed on the upper surface of the substrate assembly. The drum is installed on the main shaft and can rotate freely. One end of the steering frame is connected to the inner surface of the substrate assembly, and the other end of the steering frame is fixedly connected to a side surface of the movable frame. An angular displacement sensor is installed on the steering axle of the bogie to cooperate with the side slip swing oil cylinder to ensure the precise positioning of the side slip angle of the movable loading head. The U-shaped loading head is fixed within the frame of the steering frame; a wheel axle for installing the wheel is installed within the frame of the U-shaped loading head. The center line of the wheel axle is parallel to the center line of the main shaft. Both the outer slide rail and the inner slide rail are located on one side of the steering frame and are parallel to each other. Support rollers are provided on the upper surface of the outer slide rail. A side slip oil cylinder is installed on the surface at one end of the outer slide rail; two support oil cylinders are installed on the end surface of the movable frame at the end of the outer guide rail. The loading oil cylinder is located at the geometric center of the guiding frame and is fixed to the cross beam of the movable frame. The guiding frame is placed in the middle of the movable frame and is in sliding fit with the surface of the guiding frame through vertical guiding rollers and lateral guiding rollers to reduce the frictional resistance when the guiding frame moves.

[0013] A side slip oil cylinder is installed on the surface at one end of the outer slide rail. Two support oil cylinders are installed on the end surface of the movable frame at the end of the outer guide rail.

[0014] The surface of the movable frame close to the drum side is fixedly connected to one end of the steering frame through a steering frame mounting plate; the other end of the steering frame is axially connected to the swing axis in the substrate assembly through a ball shaft.

[0015] Two groups of vertical guiding rollers are respectively installed on the upper surface and the lower surface within the movable frame, and two groups of lateral guiding rollers are respectively installed on the two side surfaces within the movable frame through connecting plates. The guiding frame is placed in the middle of the movable frame and is supported by each of the vertical guiding rollers and lateral guiding rollers, so that each of the vertical guiding rollers and lateral guiding rollers is in sliding fit with the surface of the guiding frame. The height of the guiding frame is equal to the height of the loading head, and one end of the guiding frame is fixedly connected to one end of the U-shaped loading head. The wheel is installed on the wheel axle at the other end of the U-shaped loading head. One end of the movable frame has a connecting lug fixed to the outer slide rail; the other end of the movable frame also has a connecting lug fixed to the inner slide rail.

[0016] The substrate assembly includes a swing shaft, an outer bearing ring, a floor plate, a retaining ring and a connecting reinforcing plate. The swing shaft passes through a through hole in the floor plate, with one end located on the upper surface of the floor plate and the other end located on the lower surface of the floor plate. The connecting reinforcing plate is located on the upper surface of the floor plate and is sleeved on the swing shaft; the connecting reinforcing plate is fixed by a retaining ring. The bearing is located on the lower surface of the floor plate and is sleeved on the swing shaft.

[0017] The radius of the outer slide rail is 5000 mm. The upper surface of the outer slide rail is the working surface, and there is a grooved track on this working surface. The inner surface width of the grooved track is 55 mm. There is a mounting hole for installing a side deviation oil cylinder on the surface at one end of the outer slide rail. The radius of the inner slide rail is 3000 mm. The upper surface of the inner slide rail is the working surface, and there is a grooved track on this working surface. The inner surface width of the grooved track is 55 mm.

[0018] The bogie is a U-shaped frame structure. Its open end is used to connect the connecting plate of the movable frame, and the other end is a bearing mounting seat. The inner surface of the bearing mounting seat is a spherical surface that fits with the outer surface of the outer bearing ring. The bearing mounting seat is sleeved on the outer bearing ring, and the two are rotationally matched. When the side deviation oil cylinder works, the bogie can horizontally rotate 20° to both sides around the center line of the swing shaft, thereby driving the lateral displacement of the movable frame, and further driving the same angle of lateral deviation of the wheel, so that a lateral deviation angle is formed between the surface of the wheel and the surface of the drum; when the support oil cylinder works, the bogie can move up and down along the outer circumferential surface of the outer bearing ring, so that the movable frame can move up 50 mm. The vertical extension line of the center line of the swing shaft is tangent to point A on the outer circumferential surface of the drum, which is the closest to the wheel.

[0019] The vertical guiding roller is a double-wheel structure, including a roller frame, a roller shaft and rollers. The roller frame is a double bracket, and there are two roller mounting grooves side by side on the roller frame. The two roller shafts are placed side by side on the upper end surface of the roller frame and are fixed by roller shaft pressing plates. Each roller is installed on the roller shaft through a bearing. The lateral guiding roller has the same structure as the vertical guiding roller.

[0020] There are 8 lateral guiding rollers, which are evenly divided into two groups; the two groups of lateral guiding rollers are symmetrically and horizontally installed on the inner surface of the movable frame. The number of vertical guiding rollers is also 8, which are evenly divided into two groups; the two groups of vertical guiding rollers are symmetrically and vertically installed on the inner side surface of the movable frame. The relative sliding between the movable frame and the guiding frame is realized through the lateral guiding rollers and the vertical guiding rollers, and the weight of the loading head and all non-vertical load masses caused by loading deformation are borne.

[0021] An angular displacement sensor is arranged at the head of the push rod of the side deflection oil cylinder; a load sensor is arranged between the guiding frame and the loading oil cylinder.

[0022] The specific process of conducting a side deflection loading and rolling experiment using the side deflection loading and rolling device proposed by the present invention is as follows:

[0023] Step 1: Install the test machine wheel. The test machine wheel is installed on the wheel axle through bearings, and the wheel axle is fixedly installed on the U-shaped loading head. After installation, a thermocouple contacts the inner ring surface of the wheel bearing, and the thermocouple is connected to a data collector through a wire; the tire temperature is detected using an infrared thermometer.

[0024] Step 2: Side deflection preparation. Start the side deflection loading and rolling system, control the support oil cylinder so that the support roller contacts the upper surface of the outer slide rail, and raise the height of the movable frame by 50 mm so that the lower surface of the movable frame and the inner and outer slide rail surfaces are in a non-contact state.

[0025] Step 3: Determine the angle of the side deflection angle α of the wheel. The side deflection angle is the side deflection angle of the aircraft. The side deflection angle α = 0 to 20°.

[0026] Step 4: Control the side deflection oil cylinder so that the movable frame deflects along the outer slide rail track around the swing axis, and adjust the angle between the radial horizontal line of the wheel and the radial direction on the drum horizontal plane from 0° to 12°. The angle feedback is measured by an angle sensor installed on the swing axis. When the side deflection angle of the wheel is adjusted in place, control the support oil cylinder to unload, lower the movable frame so that the bottom of the movable frame contacts the upper surfaces of the inner and outer slide rails respectively until the support roller leaves the upper surface of the outer slide rail; use the outer slide rail fastening screw and the inner slide rail fastening screw to fasten the movable frame and the guide rail respectively.

[0027] Step 5: Adjust the test machine wheel to the critical state of loading. Control the loading oil cylinder to push the guiding frame to move along the movable frame towards the drum at a speed of 1 mm / s so that the circumferential surface of the test machine wheel contacts the circumferential surface of the stationary drum. Zero the load sensor and record the current position of the oil cylinder piston as the initial position of the wheel. At this time, the position state of the test machine wheel is the critical state position of loading.

[0028] Step 6: Determine the side deflection loading and rolling parameters.

[0029] The loading test parameters include: the working pressure output by the oil cylinder, the test load of the test bearing. Among them:

[0030] The working pressure output by the oil cylinder is determined by formula (1):

[0031]

[0032] Where: D is the inner diameter of the hydraulic cylinder, in m; F is the thrust of the hydraulic cylinder, in N; P is the working pressure, in MPa.

[0033] The radial load F of the test bearing r is determined by formula (2):

[0034] F r = F × cosα (2)

[0035] The axial load F of the test bearing α is determined by formula (3):

[0036] F α = F × sinα (3)

[0037] Step 7: Measure the rolling radius of the tire under the rated load.

[0038] The lateral offset loading and rolling system performs lateral offset loading and rolling; the loading load is collected through a load sensor, and the loading load is controlled in a PID closed loop by the control system. The cylinder of the lateral offset loading and rolling system pushes the guiding frame, thereby pushing the wheels on the U-shaped loading head to load on the surface of the drum. When the loading load reaches the rated load value, the current position of the cylinder piston is used as the rated load loading position and the coordinates of this rated load loading position are recorded, the current tire temperature is used as the initial tire temperature value and this initial temperature value is recorded, and the current wheel bearing temperature value is used as the initial bearing temperature value and this bearing initial temperature value is recorded.

[0039] Determine the tire compression under the rated load:

[0040] The tire compression s under the rated load = the initial position value of the wheel - the rated load loading position value. Both the initial position value of the wheel and the rated load loading position value are obtained through actual measurement.

[0041] Determine the rolling radius r of the tire:

[0042] The rolling radius r of the tire = the wheel diameter - the tire compression s under the rated load

[0043] According to the obtained tire compression and the rolling radius r under the rated load, control the load of the loading cylinder so that the wheel is in the loading critical state of Step 5.

[0044] Step 8: Simulate the aircraft speed.

[0045] When simulating the aircraft speed, start the drive system so that the drum rotates at a specified speed to simulate the aircraft runway. The so-called simulated aircraft runway simulates the aircraft runway through the outer circular surface of the drum and simulates the aircraft speed through the relative motion mode between the surface of the drum and the wheels.

[0046] Based on the principle that the linear speed of the wheel is the same as that of the drum, the formula (4) is obtained:

[0047] Tire rolling radius r × π × 2 × wheel rotation speed = drum diameter × π × drum rolling speed (4)

[0048] The drum rolling speed is determined by this formula (4). When the tire rolling radius r, the wheel rotation speed, the drum diameter, and the drum rolling speed are determined, the drum is driven by a motor to reach the drum rolling speed.

[0049] When simulating the speed of the aircraft, the drive system is started so that the drum rotates at a specified speed to simulate the aircraft runway. The aircraft speed is simulated by the relative movement between the surface of the drum and the surface of the wheel.

[0050] Step 9: Side slip loading rolling test. Control the loading oil cylinder, and the oil cylinder pushes the guiding frame to move along the guiding wheels of the movable frame, so that the wheel loads on the surface of the drum, and the wheel rotates passively to the rated test rotation speed under the action of friction. The loading load needs to be loaded from 0 to the rated test load within 0.3 s.

[0051] Constant speed and constant load holding stage: When the test bearing load reaches 275 KN and the rotation speed reaches 50 km / h, the rolling test is carried out while maintaining this load and rotation speed. Record the load, rotation speed, wheel bearing temperature, tire temperature, and wheel position curves in the rolling test at a sampling rate of 10 Hz.

[0052] Thus, the side slip loading rolling test of the wheel is completed.

[0053] The side slip loading rolling device for aircraft wheels described in the present invention is used to simulate the working conditions of the wheels when the aircraft lands in a crosswind, and is also applicable to the resistance loading system in the accelerated fatigue test of aircraft wheels.

[0054] The loading mechanism in the present invention adopts an integral frame structure, which has a large load-bearing capacity. The maximum test load reaches 50T, which is 2.5 times that of the existing test equipment. To ensure the safety of the test bench design, CATIA three-dimensional forming design is adopted and assisted by finite element strength calculation and analysis to ensure the mechanical design strength. As the guiding frame for loading, the frame is equipped with loading bracket support rollers, upper limit, left limit rollers and right limit rollers. The moving mode between the frame and the movable frame is the rolling movement mode through the guiding rollers distributed between the movable frame and the guiding frame, which reduces the moving resistance. The moving resistance is improved from 5KN required by the traditional rail transmission mode to 0.5KN at present, thus overcoming the drawback of excessive resistance in the existing rail loading, which leads to deviation of the loading load, and improving the reliability of the test bench and the credibility of the test parameters. In addition, due to the lever effect of the force on the rail in the traditional loading device, the strength is limited, and the limit load is 140KN. In this loading device, through the force transmission mode of 4 groups of guiding wheels on the four surfaces of the guiding frame, the ability of the test bench to bear axial load is greatly improved. The device of the present invention is designed according to an axial loading load of 250KN and can bear the braking resistance moment of the landing gear, and can complete the simulation of the working conditions of the landing gear under high load, crosswind landing, yaw and other conditions of the aircraft, providing a feasible test environment and reliable test data for the research of landing gears with better performance.

[0055] Due to the improvement of this loading device, the overall lateral loading force that can be borne is increased, and the side slip angle is increased from the original side slip limit of 15° to the current side slip limit angle of 20°. This test device is the first side slip loading and rolling device in China to meet the side slip loading and rolling test requirements of large transport aircraft landing gears, and it is also the first test device in China with a dynamic heavy load life loading of more than 500KN for landing gears.

[0056] The present invention can realize the side slip swing of the side slip loading and rolling device of the aero-wheel fatigue life test bench by using a simple driving device, overcoming the harsh requirements of manual operation for the traditional crane to pull the side slip loading and rolling system to swing back and forth to adjust the angle and the drawback of angle error in the swing angle. It uses a spherical shaft structure as the center, and a support oil cylinder is used at the tail to reduce the resistance. The side slip is dragged by a hydraulic cylinder, and an angle sensor is used for closed-loop control to achieve precise positioning of the swing angle. The accuracy is improved from the original ±1° to the current ±0.1°, reducing the labor intensity of workers and increasing the operation safety of the equipment. It provides a reliable and convenient test device for the research of aero-wheels and tires with better performance, can realize the side slip rolling test and accelerated life test of all military and civil aircraft landing gears under specified conditions, and has the characteristics of low experimental cost and easy implementation. It is a simple and feasible side slip loading and rolling device.

[0057] Compare three domestic test benches for aero-wheel fatigue life:

[0058] Brief Description of the Drawings

[0059] Figure 1 is a top view of the present invention.

[0060] Figure 2 is Figure 1 the front view of

[0061] Figure 3 is Figure 2 the sectional view of

[0062] Figure 4 is a schematic diagram of the position of the swing shaft and the drum

[0063] Figure 5 the front view of the bogie 5

[0064] Figure 6 is Figure 5 the top view of

[0065] Figure 7 is a schematic diagram of the structure of the swing shaft

[0066] Figure 8 is a schematic diagram of the structure of the inner ring of the bearing

[0067] Figure 9 is a schematic diagram of the structure of the outer ring of the bearing

[0068] Figure 10 is the side sectional view of the connecting reinforcement plate

[0069] Figure 11 is the front sectional view of the connecting reinforcement plate

[0070] Figure 12 is the top view of the connecting reinforcement plate

[0071] Figure 13a is a schematic diagram of the structure of the guide frame

[0072] Figure 13b is Figure 13a the schematic diagram of the B-B section in

[0073] Figure 13c is Figure 13a the top view of

[0074] Figure 13d is Figure 13a the schematic diagram of the A-A section in

[0075] Figure 14a is a schematic diagram of the structure of the adapter plate

[0076] Figure 14b is Figure 14a the left view of

[0077] Figure 15a It is a schematic structural diagram of a U-shaped loading head.

[0078] Figure 15b It is Figure 15a a side view of.

[0079] Figure 16a It is a schematic structural diagram of a guide wheel.

[0080] Figure 16b It is Figure 16a a side view of.

[0081] Figure 17a It is a schematic structural diagram of a movable frame.

[0082] Figure 17b It is Figure 17a a side view.

[0083] Figure 18a It is a schematic structural diagram of an inner slide rail.

[0084] Figure 18b It is Figure 18a a left view of.

[0085] Figure 19a It is a schematic structural diagram of an outer slide rail.

[0086] Figure 19b It is Figure 19a a left view of.

[0087] Figure 20a It is a schematic structural diagram of the oil cylinder seat of a loading oil cylinder.

[0088] Figure 20b It is Figure 20a a side view.

[0089] Figure 20c It is Figure 20a a top view of.

[0090] In the figure: 1. Drum wheel; 2. Main shaft; 3. Bearing seat; 4. Substrate assembly; 5. Bogie; 6. Wheel; 7. Axle; 8. U-shaped loading head; 9. Guide frame; 10. Movable frame; 11. Loading oil cylinder; 12. Lateral guide roller; 13. Outer slide rail; 14. Inner slide rail; 15. Side deviation oil cylinder; 16. Support oil cylinder; 17. Outer slide rail fastening screw; 18. Inner slide rail fastening screw; 19. Load sensor; 20. Vertical guide roller; 21. Universal joint; 22. Adapter plate; 23. Support roller; 24. Connection reinforcement plate; 25. Swing shaft; 26. Outer bearing ring; 27. Inner bearing ring; 28. Retaining ring; 29. Washer; 30. Bearing cover; 31. Support lug; 32. Steering frame mounting plate; 33. Floor plate; 34. Vertical extension line of the swing shaft center line. Detailed implementation mode

[0091] This embodiment is a side slip test loading device for the wheels of a certain type of aircraft.

[0092] The aircraft wheel side slip test device of the present invention includes a drum 1, a main shaft 2, a bearing seat 3, a base plate assembly 4, a steering frame 5, a wheel 6, a wheel axle 7, a U-shaped loading head 8, a guiding frame 9, a movable frame 10, loading cylinders 11, 12 lateral guiding rollers, an outer slide rail 13, an inner slide rail 14, a side slip cylinder 15, a support cylinder 16, an outer slide rail fastening screw 17, an inner slide rail fastening screw 18, a load sensor 19, and a vertical guiding roller 20. Among them:

[0093] The main shaft 2 is installed on the upper surface of the base plate assembly 4 through bearings. The drum is installed on this main shaft and can rotate freely. One end of the bogie 5 is connected to the inner surface of the base plate assembly, and the other end of this steering frame is fixedly connected to a side surface of the movable frame 10. An angular displacement sensor is installed on the steering shaft of the bogie 5 and is used to cooperate with the side slip swing cylinder to ensure the precise positioning of the side slip angle of the movable loading head. The U-shaped loading head 8 is fixed within the frame of this steering frame; within the frame of this U-shaped loading head, there is a wheel axle 7 for installing the wheel 6. The center line of the wheel axle is parallel to the center line of the main shaft 2.

[0094] The outer slide rail 13 and the inner slide rail 14 are both located on one side of the bogie 5, and the outer slide rail and the inner slide rail are parallel. One end of the movable frame 10 has a connecting ear plate. After the movable frame moves into place, the outer slide rail fastening screw 17 passes through this connecting ear plate to fix the movable frame to the outer slide rail; the other end of the movable frame also has a connecting ear plate. After the movable frame moves into place, the inner slide rail fastening screw 18 passes through this connecting ear plate to fix the movable frame to the inner slide rail; the positioning of the movable frame is achieved through fixed connection. There is a support roller 23 on the upper surface of the outer slide rail; this support roller is installed on the lower surface of the support cylinder 16, and the upper end of this support cylinder is fixedly connected to a support ear plate 31 on the lower surface of the movable frame 10.

[0095] The movable frame 10 is a platform for installing the movable loading part, placed flat on the slide rail, and can rotate around the axis of the swing shaft 25 in the base plate assembly with the bogie. It is a stress-bearing member for vertical loading and side slip loading and rolling of the wheel. The main load-bearing body of the movable frame is 4 rectangular cold-formed hollow steel columns with a specification of 400X200-12. Channels with a specification of 200X70-9 are welded at the bottom, middle, and upper parts of the steel columns to form a frame body, and channels of different specifications are used as rib plates for reinforcement at the main load-bearing parts. A guiding frame is installed in the middle of the movable frame, and at one end close to the wheel, it is used to install the bogie 5.

[0096] On the upper and lower surfaces within the movable frame, two sets of vertically guiding rollers 20 are respectively installed through connecting plates, and on the two side surfaces within the movable frame, two sets of laterally guiding rollers 12 are respectively installed through connecting plates. The guiding frame 9 is placed in the middle within the movable frame 10 and is supported by the respective vertically guiding rollers and laterally guiding rollers, so that the respective vertically guiding rollers and laterally guiding rollers are in sliding fit with the surface of the guiding frame to reduce the frictional resistance when the guiding frame moves. The height of the guiding frame 9 is equal to the height of the loading head, and one end of the guiding frame is fixedly connected to one end of the U-shaped loading head 8. The wheels 6 are installed on the axle 7 at the other end of the U-shaped loading head.

[0097] The surface of the movable frame close to one side of the drum 1 is fixedly connected to one end of the bogie 5 through the steering frame mounting plate 32; the other end of the steering frame is axially connected to the swing axis in the substrate assembly 45 through a ball shaft.

[0098] The substrate assembly 4 includes a swing shaft 25, an outer bearing ring 26, an inner bearing ring 27, a floor plate 33, a retaining ring 28, and a connecting reinforcing plate 24. The swing shaft passes through the through hole on the floor plate, with one end on the upper surface of the floor plate and the other end on the lower surface of the floor plate. The connecting reinforcing plate 24 is located on the upper surface of the floor plate and is sleeved on the swing shaft; the connecting reinforcing plate is fixed by the retaining ring 28. The bearing is located on the lower surface of the floor plate and is sleeved on the swing shaft through a washer 29, and from the inside to the outside are the inner bearing ring 27, the outer bearing ring 26, and the bearing cover 30 in sequence. The washer 29 is a conventional technical washer.

[0099] The lower end face of the swing shaft 25 has a positioning boss, the middle part is used for installing the inner bearing ring, and the outer circumferential surface at the upper end head has a threaded hole for installing the retaining ring 28.

[0100] The outer bearing ring 26 and the inner bearing ring 27 form a set of spherical plain bearings. The inner radius of the outer bearing ring 26 is 210 mm and the outer radius of the inner bearing ring is 210 mm; the inner hole diameter of the inner bearing ring 27 is 240 mm, the outer diameter of the middle part of the swing shaft 25 is 240 mm, and the outer diameter of the end with the threaded hole is 190 mm; there are grooves for filling grease on the outer circumferential surface of the inner bearing ring. The upper end of the outer bearing ring has a retaining ring with a boss.

[0101] The bearing cover 30 is a circular cover plate, and the outer edge of its upper surface has a boss, and fixing threaded holes are evenly distributed on the boss. The outer diameter of the bearing cover is the same as the outer diameter of the bearing mounting seat of the bogie 5, and the inner diameter is matched with the positioning stop of the inner circular surface of the bearing mounting seat.

[0102] The U-shaped loading head 8 described is the same as the prior art and is a connecting member for installing the test machine wheel 6. The U-shaped loading head 8 is made by bending and welding a steel plate with a thickness of 20 mm.

[0103] The described outer slide rail 13 is made by bending and welding a steel plate, and its radius is 5000 mm. The upper surface of the outer slide rail is the working surface, and there is a grooved track on this working surface. The inner surface width of this grooved track is 55 mm. There is an installation hole for installing the side deviation oil cylinder 15 on the surface at one end of the outer slide rail 13.

[0104] The described inner slide rail 14 is also made by bending and welding a steel plate, and its radius is 3000 mm. The upper surface of the inner slide rail is the working surface, and there is a grooved track on this working surface. The inner surface width of this grooved track is 55 mm.

[0105] The drum 1 described is the prior art, with a circumference of 7 m. The outer circumferential surface of the drum is used to simulate an aircraft runway. During the loading test, under the action of the load, the outer circumferential surface of this drum contacts the outer circumferential surface of the wheel to form a pair of friction pairs. The drum is installed on the main shaft; both ends of the main shaft are respectively installed on the bearing seats, so that the drum can rotate freely between the bearing seats at both ends.

[0106] The described bogie 5 is a U-shaped frame structure. Its open end is used to connect the connecting plate of the movable frame, and the other end is a bearing mounting seat. The inner surface of this bearing mounting seat is a spherical surface that fits with the outer surface of the bearing outer ring. This bearing mounting seat is sleeved on the bearing outer ring 26 and makes a rotational fit between the two. When the side deviation oil cylinder works, the bogie can rotate horizontally 20° to both sides respectively around the center line of the swing shaft 25, thereby driving the movable frame 10 to have a side deviation displacement and driving the wheel to have the same side deviation angle, so that a side deviation angle is formed between the surface of this wheel and the surface of the drum; when the support oil cylinder 16 works, the bogie can move up and down along the outer circumferential surface of the bearing outer ring, so that the movable frame can move up 50 mm.

[0107] The vertical extension line 34 of the center line of the swing shaft is tangent to the point A on the outer circumferential surface of the drum that is closest to the wheel.

[0108] The described adapter plate 22 is a cylindrical shape. There are evenly distributed screw holes for installing the U-shaped loading head 8 on the end face of its small outer diameter end, and there is a connecting flange at the other end. There are evenly distributed screw holes for fixing the guide frame 9 on this connecting flange. The small outer diameter end of this adapter plate is respectively matched with the through hole at one end of the U-shaped loading head and the through hole at one end of the guide frame 9. During implementation, the small diameter end of the adapter plate sequentially passes through the through hole of the guide frame 9 and the through hole of the U-shaped loading head and is fixed with screws. One end of the load sensor is installed on the end face of the other end of the adapter plate 22 through screws.

[0109] The vertical guiding roller 20 has a double-wheel structure and includes a roller frame, a roller shaft, and rollers. The roller frame is a double bracket, and there are two roller mounting grooves side by side on the roller frame. The two roller shafts are placed side by side on the upper end surface of the roller frame and are fixed by a roller shaft pressing plate. Each of the rollers is mounted on the roller shaft through a bearing.

[0110] The lateral guiding roller has the same structure as the vertical guiding roller 20.

[0111] There are 8 lateral guiding rollers 12, which are evenly divided into two groups; the two groups of lateral guiding rollers are symmetrically and horizontally mounted on the inner surface of the movable frame 10. The number of the vertical guiding rollers 20 is also 8, which are evenly divided into two groups; the two groups of vertical guiding rollers are symmetrically and vertically mounted on the inner side surface of the movable frame 10. The relative sliding between the movable frame 10 and the guiding frame 9 is realized through the lateral guiding rollers and the vertical guiding rollers 20, and the weight of the loading head and all non-vertical load masses caused by loading deformation are borne.

[0112] There are 2 support cylinders 16, which are respectively mounted on the end faces of the movable frame located on the outer guide rails. The side deviation cylinder 15 is a three-stage cylinder, and an angular displacement sensor is provided at the head of the push rod of the side deviation cylinder 15. The offset angle is realized by controlling the stroke of the cylinder push rod. The support cylinder and the side deviation cylinder are conventional cylinders.

[0113] The load sensor is mounted between the guiding frame and the loading cylinder. One end is hinged to the cylinder piston rod through a universal joint, and the other end is fixed to the guiding frame by bolts. The load sensor bears axial thrust and tension. The lateral component forces in all directions caused by equipment installation errors or frame loading deformation are transmitted from the frame to the rollers and then to the base. The load sensor is mounted between the cylinder and the guiding frame and bears pure thrust and tension. The lateral component forces caused by installation and deformation are transmitted through the frame to the roller assembly and then to the base.

[0114] During implementation, the drum 1 is fixed on the main shaft with double flat keys, positioned by the shoulder on the main shaft on one side, and directly contacts the inner ring of the bearing through a bushing on the other side. The main shaft relies on the bearing support and the bearing to support and rotate. The bracket of the bearing seat is fixed on the base plate with M48 bolts.

[0115] The side deviation swing cylinder is a three-stage cylinder. When the push rod is retracted, the full length of the cylinder is 1300 mm, the maximum stroke of the push rod is 2100 mm, and the axial thrust is 4000 kg. An angular displacement sensor is provided at the head of the push rod of the side deviation cylinder, and the offset angle is realized by controlling the stroke of the cylinder push rod.

[0116] The supporting oil cylinder is a conventional oil cylinder with a stroke of 50 mm, a cylinder diameter of 180 mm, and a rod diameter of 100 mm. The hydraulic system meets the requirements of this test bench under a working pressure of 16 Mpa.

[0117] Before the side slip loading roll test, turn on the oil pump. After retracting the oil cylinder to the initial position, loosen the fastening nuts on the outside of the 4 columns of the movable loading frame. Control the output thrust of the two supporting oil cylinders. Under the action of the supporting oil cylinders, the movable loading part rises 5 - 15 mm with the axle of the moving frame wheel under the drum as the fulcrum, so that the movable frame leaves the sliding rail support surface. Control the yaw oil cylinder, so that the movable frame rotates the required angle along the center of the axle of the moving frame wheel under the action of the side slip swing oil cylinder. Then control the rod of the supporting oil cylinder to retract, and the movable loading part falls onto the sliding rail support surface. Then lock the fastening nuts to complete the side slip movement of the movable loading head.

[0118] During implementation, one end face of the bogie 5 is installed on the movable frame 10 through the bogie 5 mounting plate 32. One end of its bearing mounting seat installs the outer ring 26 of the bearing. The inner ring 27 of the bearing is installed inside the outer ring 26 of the bearing. The swing shaft 25 passes through the inner ring 27 of the bearing, the washer, the substrate assembly 4, and the connecting reinforcing plate 24 in sequence. Among them, the connecting reinforcing plate 24 is fixed to the substrate assembly 4 through the screw holes at both ends. The retaining ring 28 is fixed to one end face of the swing shaft 25 through the screw holes on its end face. The bearing cover 30 is fixed to the bearing mounting seat of the bogie 5 through the screw holes evenly distributed on the outer ring to achieve the blocking effect on the bearing. The bogie 5 can rotate around the swing shaft on the horizontal plane through the bearing. The vertical loading load and lateral load acting on the wheel are transmitted to the bogie 5 through the movable frame. The bogie 5 acts on the swing shaft 25 through the inner ring 27 of the bearing, and is transmitted to the substrate assembly 4 through the connecting reinforcing plate by the swing shaft 25. Because the dragging system is installed on the substrate assembly 4, the reaction force of the resultant load is formed and offset. Because the impact load borne by the aircraft wheel is quite large, ordinary ball bearings have a certain clearance and are prone to fatigue damage. This kind of structural design can bear large loads for a long time without causing permanent deformation. When the movable frame needs to move and deflect, the supporting oil cylinder 16 jacks up the tail of the movable frame, so that the bogie 5 forms a certain angle in the vertical direction and on the horizontal plane around the center of the ball of the inner ring 26 of the bearing. This spherical bearing can complete the lateral deflection of the movable frame around the swing shaft 25 on the horizontal plane, and can also make the bogie 5 form a certain angle around the center of the bearing and the horizontal plane when the movable frame moves.

[0119] In this embodiment, the guiding frame 9 is welded by channel steels and is matched with the upper surface, lower surface and two side surfaces of the fixed frame through guiding rollers to realize the horizontal movement of the guiding frame. There is a threaded hole for installing the U-shaped loading head 8 in the middle of one end of the guiding frame 9. At the geometric center position of the guiding frame 9 is the loading oil cylinder 11. The loading oil cylinder 11 is installed on the oil cylinder support. The oil cylinder support 11 is fixedly installed on the cross beam of the movable frame through the threaded holes on both end faces. The oil cylinder support is welded by channel steels and strengthened with rib plates, and transferring the thrust of the loading oil cylinder 11 to the movable frame is a conventional technology. The piston rod of the loading oil cylinder 11 is connected with a universal joint 21, and a load sensor 19 is connected to the universal joint 21; the load sensor 19 is fixed by the adapter plate 22, the loading head and the guiding frame 9.

[0120] This embodiment also proposes a method for conducting a side slip loading and rolling test on the wheels of a certain aircraft model by using the side slip loading and rolling device. The side slip fatigue rolling test simulates the usage conditions of the wheels during the side slip landing of the aircraft and the life conditions under such conditions, including whether the tire has a blowout or bulge under the rated test load and speed of the wheel, whether the wheel has cracks or irrecoverable deformations, etc., and obtaining the tire temperature change curve and the wheel bearing temperature change curve under such conditions.

[0121] During the test, the load borne by a single wheel of this aircraft model when the aircraft is fully loaded is 275 KN. In this embodiment, a loading hydraulic cylinder with a piston diameter of 180 mm and a piston rod diameter of 125 mm is selected, the wheel diameter is 1200 mm, and the drum diameter is 2228 mm.

[0122] The three-phase AC variable frequency speed regulation asynchronous motor 1 adopted has a power of 250 KW and is a four-pole motor with a speed of 1490 rpm.

[0123] The specific process of this embodiment is as follows:

[0124] The first step: Install the test wheel. The test wheel is installed on the wheel axle through bearings, and the wheel axle is fixedly installed on the U-shaped loading head. After installation, the inner ring surface of the wheel bearing is in contact with the thermocouple, and the thermocouple is connected to the data collector through a wire; the tire temperature is detected by an infrared thermometer.

[0125] The second step: Side slip preparation. Loosen the outer slide rail fastening screw 17 and the inner slide rail fastening screw 18. Start the side slip loading and rolling system, control the support oil cylinder, so that the support roller contacts the upper surface of the outer slide rail, and raise the height of the movable frame by 50 mm to make the lower surface of the movable frame and the inner and outer slide rail surfaces in a non-contact state.

[0126] Step 3: Determine the angle of the wheel sideslip angle α. The sideslip angle is the sideslip angle of the aircraft. The sideslip angle α = 0 - 20°. In this embodiment, the sideslip angle α = 12°.

[0127] Step 4: Control the sideslip cylinder so that the movable frame deflects along the outer slide rail track around the swing axis, adjusting the angle between the radial horizontal line of the wheel and the radial line on the drum horizontal plane from 0° to 12°. The angle feedback is measured by an angle sensor installed on the swing axis. When the wheel sideslip angle is adjusted in place, control the support cylinder to unload, lower the movable frame, and make the bottom of the movable frame contact the upper surfaces of the inner slide rail and the outer slide rail respectively until the support roller leaves the upper surface of the outer slide rail; use the outer slide rail tightening screw 17 and the inner slide rail tightening screw 18 to fasten the movable frame and the guide rail respectively.

[0128] Step 5: Adjust the test wheel to the critical state of loading. Control the loading cylinder to push the guide frame to move along the movable frame towards the drum at a speed of 1 mm / s, so that the circumferential surface of the test wheel contacts the circumferential surface of the stationary drum. Zero the load sensor and record the current position of the cylinder piston as the initial position of the wheel. At this time, the position state of the test wheel is the critical state position of loading.

[0129] Step 6: Determine the sideslip loading and rolling parameters.

[0130] The loading test parameters include: the working pressure output by the cylinder, the test load of the test bearing. Among them:

[0131] The working pressure output by the cylinder is determined by formula (1):

[0132]

[0133] In the formula: D is the inner diameter of the hydraulic cylinder, in m; F is the thrust of the hydraulic cylinder, in N; P is the working pressure, in MPa.

[0134] The radial load F of the test bearing r is determined by formula (2):

[0135] F r = F × cosα (2)

[0136] The axial load F of the test bearing α is determined by formula (3):

[0137] F α = F × sinα (3)

[0138] In this embodiment, the diameter of the hydraulic cylinder piston is 180 mm, the working pressure output by the oil cylinder is 10.81 MPa, the aircraft load is 275 KN, the radial load of the test bearing is 269 KN, and the axial load is 57.2 KN.

[0139] Step 7: Measure the rolling radius of the tire under the rated load.

[0140] The lateral force loading and rolling system performs lateral force loading and rolling; the loading load is collected back through a load sensor, and the loading load is controlled in a PID closed loop by the control system using a conventional method. The oil cylinder of the lateral force loading and rolling system pushes the guiding frame, thereby pushing the wheel on the U-shaped loading head to load onto the surface of the drum. When the loading load reaches the rated load value, use the current position of the oil cylinder piston as the loading position under the rated load and record the coordinates of this loading position under the rated load, use the current tire temperature as the initial tire temperature value and record this initial temperature value, and use the current wheel bearing temperature value as the initial bearing temperature value and record this bearing initial temperature value.

[0141] Determine the tire compression under the rated load:

[0142] The tire compression s under the rated load = the initial position value of the wheel - the loading position value under the rated load. Both the initial position value of the wheel and the loading position value under the rated load are obtained through actual measurement.

[0143] Determine the rolling radius r of the tire:

[0144] The rolling radius r of the tire = the wheel diameter - the tire compression s under the rated load

[0145] According to the obtained tire compression and the rolling radius r under the rated load, control the load of the loading oil cylinder so that the wheel is in the loading critical state of Step 5.

[0146] Step 8: Simulate the aircraft speed.

[0147] When simulating the aircraft speed, start the drive system so that the drum rotates at a specified speed to simulate the aircraft runway. The simulated aircraft runway is to simulate the aircraft runway through the outer circumferential surface of the drum, and simulate the aircraft speed through the relative movement mode between the drum surface and the wheel.

[0148] In this embodiment, the test speed of the wheel is 50 km / h, the wheel diameter is φ1200 mm, and the drum diameter is φ2228 mm. According to the principle that the linear speed of the wheel is the same as the linear speed of the drum, the formula (4) is obtained:

[0149] The rolling radius r of the tire × π × 2 × the wheel rotation speed = the drum diameter × π × the drum rolling speed (4)

[0150] The drum rolling speed is determined by the formula (4). After the rolling radius r of the tire, the wheel speed, the drum diameter, and the drum rolling speed are determined, the drum is driven by the motor to reach the drum rolling speed.

[0151] When simulating the speed of the aircraft, the drive system is started so that the drum rotates at a specified speed to simulate the aircraft runway. The aircraft speed is simulated by the relative movement between the surface of the drum and the surface of the wheel.

[0152] Step 9: Side slip loading rolling test. Control the loading oil cylinder, and the oil cylinder pushes the guiding frame to move along the guiding wheels of the movable frame, so that the wheel loads on the surface of the drum, and the wheel rotates passively to the rated test speed under the action of friction. The loading load needs to be loaded from 0 to the rated test load within 0.3 s.

[0153] Constant speed and constant load holding stage: When the test bearing load reaches 275 KN and the speed reaches 50 km / h, the rolling test is carried out while maintaining this load and speed. Record the curves of load, speed, wheel bearing temperature, tire temperature, and wheel position in the rolling test at a sampling rate of 10 Hz.

[0154] During the test, if abnormal phenomena such as vibration and noise caused by the wheel occur, or the temperature of the bearing or tire suddenly increases, or other abnormal phenomena such as tire blowout occur, directly unload. After unloading, check whether the wheel has cracks and deformations, and whether the tire is bulging and leaking by conventional methods. Analyze the recorded data by conventional methods to measure whether the wheel has reached the end of its life. Thus, the side slip loading rolling test of the wheel is completed.

Claims

1. Lateral deviation and roll loading device for an aircraft wheel fatigue test bench, characterized in that, it includes a drum (1), a main shaft (2), a base plate assembly (4), a steering frame (5), a wheel axle (7), a U-shaped loading head (8), a guiding frame (9), a movable frame (10), a loading oil cylinder (11), an outer slide rail (13), an inner slide rail (14), a lateral deviation oil cylinder (15), a support oil cylinder (16), a load sensor (19) and vertical guiding rollers (20); wherein: the main shaft (2) is installed on the upper surface of the base plate assembly (4); the drum is installed on the main shaft and can rotate freely; one end of the steering frame (5) is connected to the inner surface of the base plate assembly, and the other end of this steering frame is fixedly connected to a side surface of the movable frame (10); an angular displacement sensor is installed on the steering shaft of the bogie (5) for cooperating with the lateral deviation swing oil cylinder to ensure the precise positioning of the lateral deviation angle of the movable loading head; the U-shaped loading head (8) is fixed within the frame of this steering frame; a wheel axle (7) for installing the aircraft wheel is installed within the frame of this U-shaped loading head; the center line of the wheel axle is parallel to the center line of the main shaft (2); both the outer slide rail (13) and the inner slide rail (14) are located on one side of the steering frame (5) and are parallel to each other; support rollers (23) are provided on the upper surface of this outer slide rail; a lateral deviation oil cylinder (15) is installed on the surface at one end of the outer slide rail (13); two support oil cylinders (16) are installed on the end face of the movable frame at the outer guide rail end; the loading oil cylinder (11) is located at the geometric center position of the guiding frame (9) and is fixed to the cross beam of the movable frame; the surface of the movable frame near the drum (1) is fixedly connected to one end of the steering frame (5); the other end of this steering frame is connected to the swing shaft (25) in the base plate assembly through a ball shaft; the guiding frame (9) is placed in the middle of the movable frame and is in sliding fit with the surface of this guiding frame through vertical guiding rollers and lateral guiding rollers to reduce the frictional resistance when the guiding frame moves; two groups of vertical guiding rollers (20) are respectively installed on the upper surface and the lower surface within the movable frame (10), and two groups of lateral guiding rollers (12) are respectively installed on the two side surfaces within this movable frame through connecting plates; the guiding frame (9) is placed in the middle of the movable frame (10) and supports this guiding frame through each of the vertical guiding rollers and lateral guiding rollers, so that each of the vertical guiding rollers and lateral guiding rollers is in sliding fit with the surface of this guiding frame; the height of the guiding frame (9) is the same as the height of the loading head, and one end of the guiding frame is fixedly connected to one end of the U-shaped loading head (8); the aircraft wheel (6) is installed on the wheel axle (7) at the other end of this U-shaped loading head; one end of the movable frame (10) has a connecting lug fixed to the outer slide rail; the other end of the movable frame also has a connecting lug fixed to the inner slide rail; The substrate assembly (4) includes a swing shaft (25), a floor plate (33), a retaining ring (28), and a connecting reinforcement plate (24); the swing shaft passes through a through hole in the floor plate, with one end located on the upper surface of the floor plate and the other end located on the lower surface of the floor plate; the connecting reinforcement plate (24) is located on the upper surface of the floor plate and is sleeved on the swing shaft; the connecting reinforcement plate is fixed by the retaining ring (28); the bearing is located on the lower surface of the floor plate and is sleeved on the swing shaft.

2. The side slip and roll loading device of the aircraft wheel fatigue test bench according to claim 1, characterized in that, the radius of the outer slide rail (13) is 5000 mm; the upper surface of the outer slide rail is the working surface, and there is a grooved track on this working surface, and the inner surface width of the grooved track is 55 mm; there is a mounting hole for installing a side slip oil cylinder (15) on the surface at one end of the outer slide rail (13); the radius of the inner slide rail (14) is 3000 mm; the upper surface of the inner slide rail is the working surface, and there is a grooved track on this working surface, and the inner surface width of the grooved track is 55 mm.

3. The side slip and roll loading device of the aircraft wheel fatigue test bench according to claim 1, characterized in that, the bogie (5) is a U-shaped frame structure, the open end of which is used to connect the connecting plate of the movable frame, and the other end is a bearing mounting seat, and the inner surface of the bearing mounting seat is a spherical surface that fits with the outer surface of the bearing outer ring; the bearing mounting seat is sleeved on the bearing outer ring (26), and the two are rotationally matched; when the side slip oil cylinder works, the bogie (5) can rotate horizontally 20° to both sides around the center line of the swing shaft (25), so as to drive the movable frame (10) to have a side slip displacement, and further drive the wheel to have the same side slip angle, so that a side slip angle is formed between the surface of the wheel and the surface of the drum; when the support oil cylinder (16) works, the bogie (5) can move up and down along the outer circumferential surface of the bearing outer ring, so that the movable frame can move up 50 mm; the vertical extension line (34) of the center line of the swing shaft is tangent to the point A on the outer circumferential surface of the drum that is closest to the wheel.

4. The side slip and roll loading device of the aircraft wheel fatigue test bench according to claim 1, characterized in that, the vertical guiding roller (20) is a double-wheel structure, including a roller frame, a roller shaft, and rollers; the roller frame is a double support, and there are two roller mounting grooves arranged side by side on the roller frame; the two roller shafts are arranged side by side on the upper end surface of the roller frame and are fixed by roller shaft pressing plates; each roller is installed on the roller shaft through a bearing; the lateral guiding roller has the same structure as the vertical guiding roller (20).

5. The side slip and roll loading device of the aircraft wheel fatigue test bench according to claim 1, characterized in that, There are 8 lateral guiding rollers (12), which are evenly divided into two groups; the two groups of lateral guiding rollers are symmetrically and horizontally installed on the inner surface of the movable frame (10); the number of the vertical guiding rollers (20) is also 8, and they are evenly divided into two groups; the two groups of vertical guiding rollers are symmetrically and vertically installed on the inner side surface of the movable frame (10); the relative sliding between the movable frame (10) and the guiding frame (9) is realized through the lateral guiding rollers and the vertical guiding rollers (20), and the weight of the loading head and all non-vertical load masses caused by loading deformation are borne.

6. The side slip and roll loading device of the aircraft wheel fatigue test bench according to claim 1, characterized in that, an angular displacement sensor is arranged at the head of the push rod of the side slip oil cylinder; a load sensor (19) is arranged between the guiding frame and the loading oil cylinder.

7. A method for conducting a side slip and roll loading experiment using the side slip and roll loading device according to claim 1, characterized in that, the specific process is as follows: The first step: Install the test aircraft wheel; the test aircraft wheel is installed on the wheel axle through a bearing, and the wheel axle is fixedly installed on the U-shaped loading head; after installation, the inner ring surface of the wheel bearing is in contact with the thermocouple, and the thermocouple is connected to the data collector through a wire; the tire temperature is detected using an infrared thermometer. The second step: Side slip preparation; Start the side slip and roll loading system, control the support oil cylinder, so that the support roller contacts the upper surface of the outer slide rail, and raise the height of the movable frame by 50 mm, so that the lower surface of the movable frame and the inner and outer slide rail surfaces are in a non-contact state. The third step: Determine the angle of the side slip angle α of the aircraft wheel; the side slip angle is the side slip angle of the aircraft; the side slip angle α = 0 - 20°. The fourth step: Control the side slip oil cylinder, so that the movable frame deflects along the outer slide rail track around the swing axis, and adjust the angle between the radial horizontal line of the aircraft wheel and the radial direction on the drum horizontal plane from 0° to 12°, and the angle feedback is measured by the angle sensor installed on the swing axis; when the side slip angle of the aircraft wheel is adjusted in place, control the support oil cylinder to unload, lower the movable frame, so that the bottom of the movable frame contacts the upper surfaces of the inner slide rail and the outer slide rail respectively, until the support roller leaves the upper surface of the outer slide rail. The fifth step: Adjust the test aircraft wheel to the critical state of loading; Control the loading oil cylinder to push the guiding frame to move along the movable frame towards the drum at a speed of 1 mm / s, so that the circumferential surface of the test aircraft wheel contacts the circumferential surface of the stationary drum; zero the load sensor, and record the current position of the oil cylinder piston as the initial position of the aircraft wheel; the position state of the test aircraft wheel at this time is the critical state position of loading. The sixth step: Determine the side slip and roll loading parameters; the loading test parameters include: the working pressure output by the oil cylinder, the test load of the test bearing; where: The working pressure P output by the oil cylinder is determined by formula (1): In the formula: D is the inner diameter of the hydraulic cylinder, in m; F is the thrust of the hydraulic cylinder, in N; P is the working pressure, in MPa; The radial load F of the test bearing r is determined by Equation (2): F r = F × cos α (2) Axial load F of the test bearing α Determined by formula (3): F α = F × sin α (3) Step 7: Measure the rolling radius of the tire under the rated load; conduct side slip and roll loading on the side slip and roll loading system; the loading load is collected through the load sensor, and the PID closed-loop control is performed by the control system to load the load; the oil cylinder of the side slip and roll loading system pushes the guiding frame, thereby pushing the wheels on the U-shaped loading head to load onto the surface of the drum; when the loading load reaches the rated load value, take the current position of the oil cylinder piston as the loading position under the rated load and record the coordinates of this loading position under the rated load, take the current tire temperature as the initial tire temperature value and record this initial temperature value, and take the current wheel bearing temperature value as the initial bearing temperature value and record this initial bearing temperature value; Determine the tire compression under the rated load: The tire compression s under the rated load = the initial position value of the wheel - the loading position value under the rated load; both the initial position value of the wheel and the loading position value under the rated load are obtained through actual measurement; Determine the rolling radius r of the tire: The rolling radius r of the tire = the wheel diameter - the tire compression s under the rated load According to the obtained tire compression and the rolling radius r under the rated load, control the load of the loading oil cylinder so that the wheel is in the loading critical state of Step 5; Step 8: Simulate the aircraft speed; when simulating the aircraft speed, start the drive system to make the drum rotate at a specified speed to simulate the aircraft runway. The simulated aircraft runway is to simulate the aircraft runway through the outer surface of the drum, and simulate the aircraft speed through the relative movement mode between the surface of the drum and the wheel; According to the principle that the linear speed of the wheel is the same as the linear speed of the drum, the formula (4) is obtained: The rolling radius r of the tire × π × 2 × the wheel rotation speed = the drum diameter × π × the drum rolling speed (4) Determine the drum rolling speed through this formula (4); when the rolling radius r of the tire, the wheel rotation speed, the drum diameter, and the drum rolling speed are determined, drive the drum to reach the drum rolling speed through the motor; When simulating the aircraft speed, start the drive system to make the drum rotate at a specified speed to simulate the aircraft runway; simulate the aircraft speed through the relative movement between the surface of the drum and the surface of the wheel; Step 9: Side slip and roll loading test; control the loading oil cylinder to push the guiding frame to move along the guiding wheel of the movable frame, so that the wheel loads onto the surface of the drum, and the wheel is driven to rotate passively to the rated test rotation speed under the action of friction; the loading load needs to be loaded from 0 to the rated test load within 0.3 s; Constant speed and constant load holding stage: when the test bearing load reaches 275 KN and the rotation speed reaches 50 km / h, maintain this load and rotation speed for the rolling test; record the load, rotation speed, wheel bearing temperature, tire temperature, and wheel position curves in the rolling test at a sampling rate of 10 Hz; Thus, the side slip and roll loading test of the wheel is completed.

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