Axle box shear pad heat engine coupling fatigue test bench of truck bogie

Abstract

The invention relates to a truck bogie axle box shear pad heat engine coupling fatigue test bench, and relates to the axle box shear pad technical field, the truck bogie axle box shear pad heat engine coupling fatigue test bench comprises a support, a workbench and loading devices, the loading devices are arranged on the support, the plurality of loading devices respectively provide loading forces in a plurality of directions for the axle box shear pad, a restraining assembly and a loading device are sequentially arranged on the workbench from bottom to top in the vertical direction; the loading device is connected with the restraining assembly and used for applying loading force to the axle box shearing pad. The restraining assembly is used for clamping the axle box shearing pad and is electrically connected with the heating device; the loading device, the workbench and the support are matched with one another to load the axle box shearing pad in multiple directions. By arranging the loading device and the heating device, mechanical loads and temperature loads in multiple directions can be applied to the axle box shear pad at the same time, so that the load condition of the axle box shear pad in a real working environment is simulated, and the fatigue performance of the axle box shear pad is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of axle box shear pads, and particularly to a thermal-mechanical coupling fatigue test bench for axle box shear pads of a freight car bogie. Background Art

[0002] The axle box shear pad adopts a special sandwich structure, with two thin steel plates on the upper and lower layers and rubber in an inner-inclined-eight shape in the middle layer. During application, the axle box shear pad mainly bears compressive loads in the third direction, shear loads in the first and second directions, and a large amount of thermal loads generated during vehicle braking. Due to the cyclic action of mechanical loads and thermal loads, the rubber layer of the axle box shear pad will age, which does not conform to the original design value, directly affecting the dynamic performance of the vehicle. At the same time, the rapid aging and cracking of the axle box shear pad increase the operation cost of the vehicle. The reason is that the dynamic fatigue test of the axle box shear pad is not accurately carried out. As a rubber component, both temperature loads and mechanical loads have a great impact on the fatigue characteristics and service life of the axle box shear pad. Conducting fatigue tests under mechanical loads alone or temperature loads alone is not comprehensive and cannot evaluate the fatigue performance of the axle box shear pad under the simultaneous action of mechanical loads and temperature loads in three directions. Therefore, a thermal-mechanical coupling fatigue test bench for axle box shear pads of a freight car bogie is proposed. Summary of the Invention

[0003] The present invention provides a thermal-mechanical coupling fatigue test bench for axle box shear pads of a freight car bogie, which is used to simulate the dynamic fatigue performance of the axle box shear pad in a real application environment.

[0004] The present invention provides a thermal-mechanical coupling fatigue test bench for axle box shear pads of a freight car bogie, including a bracket, a workbench and a loading device. The loading device is installed on the bracket, and there are multiple loading devices. The multiple loading devices respectively provide loading forces for the axle box shear pad in multiple directions, where:

[0005] A constraint component and a loading device are sequentially arranged on the workbench from bottom to top in the vertical direction;

[0006] The loading device is connected to the constraint component and is used to apply the loading force to the axle box shear pad;

[0007] The constraint component is used to clamp the axle box shear pad, and the constraint component is electrically connected to a heating device;

[0008] The loading device, the workbench and the bracket cooperate with each other to load the axle box shear pad in multiple directions.

[0009] In one embodiment, the loading device includes a loading crossbeam. A force transmission device is provided at the center of the bottom of the loading crossbeam. A three-dimensional force sensor is provided at the bottom of the force transmission device. An upper heat insulation plate is provided at the bottom of the three-dimensional force sensor. The constraint assembly is provided at the bottom of the upper heat insulation plate. A lower heat insulation plate is provided at the bottom of the constraint assembly.

[0010] In one embodiment, the loading device further includes a first hydraulic actuator, a second hydraulic actuator, and a third hydraulic actuator;

[0011] The first hydraulic actuator is used to provide a loading force in a first direction. The first hydraulic actuator is arranged along the first direction on one side of the axle box shear pad. The output end of the first hydraulic actuator is connected to the constraint assembly;

[0012] The second hydraulic actuator is used to provide a loading force in a second direction. The second hydraulic actuator is arranged along the second direction on one side of the axle box shear pad. The output end of the second hydraulic actuator is connected to the constraint assembly;

[0013] The third hydraulic actuator is used to provide a loading force in a third direction. The third hydraulic actuator is arranged along the third direction on the top of the loading crossbeam. The output end of the third hydraulic actuator is connected to the loading crossbeam.

[0014] In one embodiment, the workbench includes a first linear guide mechanism and a second linear guide mechanism. The second linear guide mechanism is located on the top of the first linear guide mechanism. The lower heat insulation plate is provided on the top of the second linear guide mechanism, where:

[0015] The first linear guide mechanism is used to release the degree of freedom of the axle box shear pad in the first direction;

[0016] The second linear guide mechanism is used to release the degree of freedom of the axle box shear pad in the second direction.

[0017] In one embodiment, the constraint assembly includes an upper constraint plate and a lower constraint plate which are arranged oppositely. The axle box shear pad is clamped between the upper constraint plate and the lower constraint plate.

[0018] In one embodiment, grooves are formed on the surface of the upper constraint plate close to the axle box shear pad and the surface of the lower constraint plate close to the axle box shear pad. Thermocouples are arranged in each of the grooves. Each thermocouple is electrically connected to the heating device.

[0019] In one embodiment, the bracket includes a plurality of columns and a cross-shaped crossbeam. The tops of the plurality of columns are all connected to the cross-shaped crossbeam. The lower parts of two adjacent columns are respectively installed with the first hydraulic actuator and the second hydraulic actuator. A plurality of the third hydraulic actuators are provided at the bottom of the cross-shaped crossbeam. The columns are arranged on a base.

[0020] In one embodiment, the base is further provided with the workbench.

[0021] In one embodiment, both ends of the first hydraulic actuator and the second hydraulic actuator are connected to the installation component and the constraint component installed on the column through spherical hinges. Both ends of the third hydraulic actuator are connected to the installation component installed on the cross beam and the loading beam through spherical hinges.

[0022] In one embodiment, third linear guide mechanisms are provided on the corresponding sides of two opposite columns, and the two third linear guide mechanisms are respectively connected to both ends of the loading beam.

[0023] Compared with the prior art, the advantages of the present invention are that by providing a loading device, mechanical loads in multiple directions can be applied to the axle box shear pad, and by providing a heating device, temperature loads can be applied to the axle box shear pad. The simultaneous application of mechanical loads and temperature loads can simulate the load conditions received by the axle box shear pad in the actual working environment, so as to obtain the fatigue performance of the axle box shear pad. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Hereinafter, the present invention will be described in more detail based on embodiments and with reference to the drawings.

[0025] Figure 1 is a schematic diagram of the overall structure of the thermo-mechanical coupling fatigue test bench of the present invention;

[0026] Figure 2 is a schematic diagram of the structure of the axle box shear pad in the present invention;

[0027] Figure 3 is a schematic diagram of the structure of the upper constraint plate of the present invention;

[0028] Figure 4 is a schematic diagram of the structure of the lower constraint plate of the present invention;

[0029] Figure 5 is Figure 1 a partial schematic diagram of A;

[0030] Reference Signs:

[0031] 1. Bracket; 101. Column; 102. Cross-shaped crossbeam; 2. Loading device; 201. Second hydraulic actuator; 202. First hydraulic actuator; 203. Loading crossbeam; 204. Third linear guide mechanism; 205. Force transmission device; 206. Third hydraulic actuator; 3. Constraint assembly; 301. Upper constraint plate; 302. Lower constraint plate; 4. Workbench; 401. First linear guide mechanism; 402. Second linear guide mechanism; 5. Base; 6. Upper heat insulation plate; 7. Lower heat insulation plate; 8. Three-dimensional force sensor; 9. Heating device; 10. Axle box shear pad. Detailed implementation mode

[0032] The present invention will be further described below in conjunction with the accompanying drawings.

[0033] Refer to Figures 1 to 5 , a thermal-mechanical coupling fatigue test bench for the axle box shear pad of a freight car bogie, comprising a bracket 1, a workbench 4 and a loading device 2. The loading device 2 is installed on the bracket 1 through a mounting assembly. There are multiple loading devices 2, and the multiple loading devices 2 respectively provide loading forces for the axle box shear pad 10 in multiple directions. Among them: a constraint assembly 3 and a loading device 2 are sequentially arranged on the workbench 4 from bottom to top in the vertical direction; the loading device 2 is connected to the constraint assembly 3 and is used to apply the loading force to the axle box shear pad 10; the constraint assembly 3 is used to clamp the axle box shear pad 10, and the constraint assembly 3 is electrically connected to the heating device 9; the loading device 2, the workbench 4 and the bracket 1 cooperate with each other to load the axle box shear pad 10 in multiple directions. In this embodiment, loading forces in three directions, namely the first direction, the second direction and the third direction, are set for the axle box shear pad 10. Among them, the third direction is the loading force perpendicular to the ground direction, and the three directions are perpendicular to each other in pairs.

[0034] In order to better implement the invention, refer to Figure 3 and Figure 4, in one embodiment, the constraint component 3 includes an upper constraint plate 301 and a lower constraint plate 302 which are oppositely arranged, and the axle box shear pad 10 is clamped between the upper constraint plate 301 and the lower constraint plate 302. Grooves are provided on the surface of the upper constraint plate 301 close to the axle box shear pad 10 and on the surface of the lower constraint plate 302 close to the axle box shear pad 10. Double-layer thermocouples are arranged in each groove, and each thermocouple is electrically connected to the heating device 9. To ensure that the axle box shear pad 10 can be heated evenly, the grooves can be arranged as multiple strip-shaped grooves, or arranged in an S shape along the surfaces of the upper constraint plate 301 and the lower constraint plate 302. The thermocouples are all electrically connected to the heating device 9. A temperature sensor is also provided in the constraint component 3 for obtaining the temperature of the tested axle box shear pad 10 in real time. The temperature sensor transmits the temperature signal to the control system, and the control system controls the heating device 9 according to the preset temperature and the actual temperature. The heating device 9 heats the axle box shear pad 10. To meet the fatigue test requirements, the preset temperature is 70 °C, and the axial shear pad is heated intermittently, with the number of heating times being 120,000 times. When the heating device 9 heats the axle box shear pad 10, if the temperature sensor detects that the actual temperature of the axle box shear pad 10 is lower than the preset temperature, the temperature sensor transmits a signal to the control system, and the control system controls the heating device 9 to heat the axle box shear pad 10 until the temperature sensor detects that the temperature of the axle box shear pad 10 meets the preset temperature; if the temperature sensor detects that the temperature of the axle box shear pad 10 is higher than the preset temperature, the temperature sensor transmits a signal to the control system, and the control system controls the heating device 9 to stop heating, so that the axle box shear pad 10 cools down by itself until the preset temperature.

[0035] A number of bolt holes are provided around the upper constraint plate 301 and around the lower constraint plate 302, and the bolt holes of the upper constraint plate 301 and the lower constraint plate 302 correspond to each other one by one. The axle box shear pad 10 is clamped between the upper constraint plate 301 and the lower constraint plate 302 by bolts.

[0036] To ensure the stability of the clamping of the axle box shear pad 10 by the constraint component 3, slots can also be provided on the surfaces of the upper constraint plate 301 and the lower constraint plate 302 close to the axle box shear pad 10. The convex parts of the upper and lower surface steel plates of the axle box shear pad 10 are respectively embedded into the slots of the upper constraint plate 301 and the lower constraint plate 302, and then the upper constraint plate 301 and the lower constraint plate 302 are fixed by bolts to realize the clamping of the axle box shear pad 10.

[0037] To better implement the present invention, refer to Figure 2 , the axle box shear pad 10 has a structure in which an upper steel plate and a lower steel plate sandwich rubber in the middle, and the side view of the rubber presents an "eight" shape. In this embodiment, the direction perpendicular to the side view of the rubber is the first direction, and the direction perpendicular to the front view of the rubber is the second direction, as shown in Figure 5 .

[0038] For better implementation of the present invention, with reference to Figure 1 , in one embodiment, the loading device 2 includes a first hydraulic actuator 202, a second hydraulic actuator 201, and a third hydraulic actuator 206; the first hydraulic actuator 202 is configured to provide a loading force in a first direction, the first hydraulic actuator 202 is disposed on one side of the axle box shear pad 10 along the first direction, and an output end of the first hydraulic actuator 202 is connected to the restraint assembly 3; the second hydraulic actuator 201 is configured to provide a loading force in a second direction, the second hydraulic actuator 201 is disposed on one side of the axle box shear pad 10 along the second direction, and an output end of the second hydraulic actuator 201 is connected to the restraint assembly 3, that is, the output end of the first hydraulic actuator 202 is connected to a connecting plate through a spherical hinge, the connecting plate is connected to a lower restraint plate 302 of the restraint assembly 3, and the connecting plate is mounted on a side surface of the lower restraint plate 302; the third hydraulic actuator 206 is configured to provide a loading force in a third direction, the third hydraulic actuator 206 is disposed on top of the loading cross beam 203 along the third direction, and an output end of the third hydraulic actuator 206 is connected to the loading cross beam 203 by a spherical hinge.

[0039] The first hydraulic actuator 202, the second hydraulic actuator 201, and the third hydraulic actuator 206 each include a cylinder block and an actuating rod. The cylinder block is used to store hydraulic oil. Under the pressure formed by the hydraulic oil in the cylinder block, the actuating rod is pushed to expand and contract. The ends of the actuating rods of the first hydraulic actuator 202 and the second hydraulic actuator 201 away from the cylinder block are connected to the connecting plate on the side surface of the lower restraint plate through spherical hinges, and the end of the actuating rod of the third hydraulic actuator 206 away from the cylinder block is connected to a mounting member on the loading cross beam 203 through a spherical hinge.

[0040] In the third direction, to ensure that a loading force in the third direction is applied to the axle box shear pad 10, the loading device 2 further includes a loading cross beam 203. A force transmission device 205 is provided at the center of the bottom of the loading cross beam 203. A three-dimensional force sensor 8 is provided at the bottom of the force transmission device 205. An upper heat insulation plate 6 is provided at the bottom of the three-dimensional force sensor 8. A restraint assembly 3 is provided at the bottom of the upper heat insulation plate 6. A lower heat insulation plate 7 is provided at the bottom of the restraint assembly 3, that is, an upper heat insulation plate 6 is provided between the three-dimensional force sensor 8 and the upper restraint plate 301, and a lower heat insulation plate 7 is provided between the lower restraint plate 302 and the second linear guide mechanism 402. The upper heat insulation plate 6 and the lower heat insulation plate 7 are used to prevent the heat received by the axle box shear pad 10 from being transferred outwards, thereby reducing the test error caused by a large difference between the heat received by the axle box shear pad 10 and the heat received under actual working conditions.

[0041] To ensure the accurate simulation of the stresses on the axle box shear pad 10 in three directions under actual working conditions, a three-dimensional force sensor 8 is provided at the bottom of the force transmission device 205, and an upper heat insulation plate 6 is provided between the three-dimensional force sensor 8 and the upper constraint plate 301. During the loading in the first direction and the second direction, there will inevitably be frictional forces between the first linear guide mechanism 401 and the second linear guide mechanism 402. Therefore, a part of the first-direction loading force and the second-direction loading force applied by the first hydraulic actuator 202 and the second hydraulic actuator 201 to the axle box shear pad 10 will inevitably be consumed by the frictional forces and cannot be fully loaded onto the axle box shear pad 10, that is, the loading forces generated by the first hydraulic actuator 202 and the second hydraulic actuator 201 are greater than the loading forces actually acting on the axle box shear pad 10. When the first-direction and second-direction loading forces are preset, the loading force actually received by the axle box shear pad 10 fails to meet the test requirements due to the action of the frictional forces. Therefore, a three-dimensional force sensor 8 is provided to monitor the stress condition of the axle box shear pad 10 in real time. The three-dimensional force sensor 8 transmits the force signals in the three directions received by the axle box shear pad 10 to the control system. The control system, based on the preset loading force and the actual loading force condition, transmits signals to the first hydraulic actuator 202, the second hydraulic actuator 201, and the third hydraulic actuator 206 to automatically compensate the axle box shear pad 10, so as to ensure that the simulated loading force condition is consistent with the stress condition borne by the axle box shear pad 10 under actual working conditions.

[0042] For better implementation of the present invention, with reference to Figure 1 and Figure 5 , in an embodiment, the workbench 4 includes a first linear guide mechanism 401 and a second linear guide mechanism 402. The second linear guide mechanism 402 is located on the top of the first linear guide mechanism 401, and a lower heat insulation plate 7 is provided on the top of the second linear guide mechanism 402, wherein: the first linear guide mechanism 401 is used to release the degree of freedom of the axle box shear pad 10 in the first direction; the second linear guide mechanism 402 is used to release the degree of freedom of the axle box shear pad 10 in the second direction. The first hydraulic actuator 202 applies a periodic load in the first direction to the axle box shear pad 10, which will cause the axle box shear pad 10 to generate reciprocating displacement changes along the first linear guide mechanism 401. Similarly, the second hydraulic actuator 201 applies a periodic load in the second direction to the axle box shear pad 10, which will cause the axle box shear pad 10 to generate reciprocating displacement changes along the second linear guide mechanism 402. This periodic displacement change is the key to simulating the first-direction and second-direction alternating stresses borne by the axle box shear pad 10 under actual working conditions.

[0043] For better implementation of the present invention, with reference to Figure 1, in one embodiment, the bracket 1 includes a plurality of columns 101 and a cross-shaped crossbeam 102. At least three columns 101 are provided. To ensure the stability of the entire test process, in this embodiment, four columns 101 are provided. The tops of the four columns 101 are all connected to the ends of the cross-shaped crossbeam 102. A plurality of third hydraulic actuators 206 are provided at the bottom of the cross-shaped crossbeam 102. A first hydraulic actuator 202 and a second hydraulic actuator 201 are respectively installed at the lower parts of two adjacent columns 101. The columns 101 are arranged on the base 5.

[0044] To better implement the present invention, refer to Figure 1 , in one embodiment, the base 5 is further provided with a workbench 4, and the workbench 4 and the force transmission device 205 are on the same vertical line.

[0045] To better implement the present invention, refer to Figure 1 , in one embodiment, third linear guide mechanisms 204 are provided on the corresponding sides of two opposite columns 101. The two third linear guide mechanisms 204 are respectively connected to both ends of the loading crossbeam 203. The third linear guide mechanism 204 defines the moving direction of the loading crossbeam 203, restricting the movement of the loading crossbeam 203 in the first direction and the second direction, ensuring that the loading crossbeam 203 can move up and down stably. Since the loading crossbeam 203 has a certain length, to ensure the uniform load applied by the loading crossbeam 203, two third hydraulic actuators 206 are provided in this embodiment.

[0046] The first linear guide mechanism 401, the second linear guide mechanism 402 and the third linear guide mechanism 204 all include sliders and slide rails. The sliders and the slide rails are connected by multiple rows of ball bearings. The output end of the first hydraulic actuator 202 controls the lower restraint plate 302, thereby driving the lower heat insulation plate 7, the second linear guide mechanism 402 and the slider that is connected to the bottom of the second linear guide mechanism 402 and cooperates with the slide rail of the first linear guide mechanism 401 to reciprocate along the slide rail of the first linear guide mechanism 401. The output end of the second hydraulic actuator 201 controls the lower restraint plate 302, thereby driving the lower heat insulation plate 7 and the slider of the second linear guide mechanism 402 connected to the lower heat insulation plate 7 to reciprocate along the slide rail of the second linear guide mechanism 402. The third linear guide mechanism 204 is provided with two groups, and the sliders of the two groups are respectively connected to both ends of the loading crossbeam 203. The sliders move on the corresponding slide rails, and the output end of the third hydraulic actuator 206 controls the sliders connected to both ends of the loading crossbeam 203 to move along the slide rails of the third linear guide mechanism 204.

[0047] When the third hydraulic actuator 206 works, the output end drives the loading crossbeam 203 to move downward along the third linear guide mechanism 204, thereby driving the force transmission device 205, the three-dimensional force sensor 8, the upper heat insulation plate 6 and the upper restraint plate 301 to move downward, so that the upper restraint plate 301 and the lower restraint plate 302 clamp the axle box shear pad 10, thereby applying a load in the third direction to the axle box shear pad 10. The load in the third direction is used to simulate the load in the actual situation. Regarding the standard of the fatigue load of the bogie axle box shear pad 10, the specific requirement in "TB / T - 3268 - 2011 Rubber Pad for Railway Freight Car Bearing Saddle" is that the fatigue load in the third direction is 117.6 ± 58.8 kN, where 117.6 kN is the pre-pressure in the third direction, simulating the load of the vehicle. On this basis, fatigue cyclic loading is carried out, and the load amplitude is ± 58.8 kN.

[0048] The specific requirement in "TB / T - 3268 - 2011 Rubber Pad for Railway Freight Car Bearing Saddle" is that the fatigue load in the first direction is ± 39.2 kN, and the fatigue load in the second direction is - 39.2 kN to 58.8 kN.

[0049] The fatigue loading frequencies in the first direction, the second direction and the third direction are 2 - 5 Hz. In this embodiment, 4 Hz is preferably selected. During the test, the number of cycles in both the first direction and the second direction is 500,000 times. Taking the extending direction of the output ends of the first hydraulic actuator 202 and the second hydraulic actuator 201 as positive, one positive and one negative are counted as one cycle. At this time, the number of cycles in the third direction is 2,000,000 times. Taking the downward extending direction of the output end of the third hydraulic actuator 206 as positive, one positive and one negative are counted as one cycle. Cooperating with the heating device 9 to heat the axle box shear pad 10, the temperature loading and the mechanical loading are carried out simultaneously. After the loading is completed, check whether there are cracks and delamination on the surface of the axle box shear pad 10 to evaluate the fatigue performance of the axle box shear pad 10. By simulating the stress cycle and the fatigue damage process, the fatigue performance of the axle box shear pad 10 under the three-way loading forces in the third direction, the second direction and the first direction under the actual working conditions can be evaluated.

[0050] To better implement the present invention, referring to Figure 1 , in one embodiment, both ends of the first hydraulic actuator 202 and the second hydraulic actuator 201 are respectively connected to the connecting plates on the upper sides of the mounting components and the restraint components 3 installed on the columns 101 through spherical hinges. Both ends of the third hydraulic actuator 206 are connected to the mounting components installed on the cross beam and the loading crossbeam 203 through spherical hinges. The mounting component includes two clamping plates, which clamp the bracket 1 and are fixed by a plurality of screws and nuts. The mounting ends of the first hydraulic actuator 202, the second hydraulic actuator 201 and the third hydraulic actuator 206 are connected to the clamping plates through spherical hinges, and the output end of the third hydraulic actuator 206 is connected to the clamping plate through a spherical hinge.

[0051] The loading device 2, the heating device 9, the temperature sensor, the three-dimensional force sensor 8 and the control system are electrically connected respectively.

[0052] Based on the above axle box shear pad thermo-mechanical coupling fatigue test bench for freight car bogies, its working principle is as follows:

[0053] First, place the axle box shear pad 10 between the upper restraint plate 301 and the lower restraint plate 302. Control the output end of the third hydraulic actuator 206 to move downward through the control system. The output end will drive the loading crossbeam 203 to move downward along the third linear guide mechanism 204. The loading crossbeam 203 drives the force transmission device 205, the three-dimensional sensor, the upper heat insulation plate 6 and the upper restraint plate 301 connected to the bottom to move downward until the upper restraint plate 301 and the lower restraint plate 302 clamp the axle box shear pad 10. Fix the upper restraint plate 301 and the lower restraint plate 302 with screws and bolts. Turn on the heating device 9, and the heating device 9 heats the axle box shear pad 10. The temperature sensor detects the temperature received by the axle box shear pad 10. When there is a deviation between the real-time temperature and the system preset temperature, the temperature sensor feeds back the signal to the control system, and the control system controls the heating device 9 to perform temperature compensation on the axle box shear pad 10 to ensure that the temperature environment of the axle box shear pad 10 is closest to the actual working conditions during the test. The control system controls the first hydraulic actuator 202 and the second hydraulic actuator 201 to apply periodic loading forces on the axle box shear pad 10 fixed by the constrained component 3 along the first direction and the second direction respectively, so that the axle box shear pad 10 has reciprocating displacements along the first linear guide mechanism 401 and the second linear guide mechanism 402. The three-dimensional force sensor 8 monitors the real force conditions of the axle box shear pad 10 in three directions and transmits the force signal to the control system at the same time. The control system controls the third hydraulic actuator 206, the second hydraulic actuator 201 and the first hydraulic actuator 202 to compensate the loading force on the axle box shear pad 10 according to the difference between the preset load and the real load. When applying mechanical loads in three directions and temperature loads on the axle box shear pad 10 at the same time, after applying mechanical loads in three directions and temperature loads for several times, take the axle box shear pad 10 off the test bench and observe whether there are cracks and delamination on its surface, and then the fatigue performance of the axle box shear pad 10 under the real application environment can be obtained.

[0054] Although the present invention has been described with reference to the preferred embodiments, various improvements can be made to it and components therein can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present invention is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A thermal-mechanical coupling fatigue test bench for axle box shear pads of a freight car bogie, characterized in that: It includes a bracket, a workbench and a loading device, wherein the loading device is installed on the bracket, and a plurality of loading devices are provided, and the plurality of loading devices respectively provide loading forces in multiple directions for the axle box shear pad, wherein: The workbench is provided with a restraining assembly and a loading device in sequence from bottom to top in the vertical direction; The loading device is connected to the constraint assembly and is used to apply a loading force to the axle box shear pad; The constraint assembly is used to clamp the axle box shear pad, and the constraint assembly is electrically connected to the heating device; The loading device, the workbench and the bracket cooperate with each other to load the axle box shear pad in multiple directions.

2. The axle box shear pad thermal-mechanical coupling fatigue test bench for a freight car bogie according to claim 1, characterized in that: The loading device includes a loading beam, a force transmission device is provided at the bottom center of the loading beam, a three-dimensional force sensor is provided at the bottom of the force transmission device, an upper insulation board is provided at the bottom of the three-dimensional force sensor, the constraint assembly is provided at the bottom of the upper insulation board, and a lower insulation board is provided at the bottom of the constraint assembly.

3. The axle box shear pad thermal-mechanical coupling fatigue test bench for a freight car bogie according to claim 1, characterized in that: The loading device further comprises a first hydraulic actuator, a second hydraulic actuator and a third hydraulic actuator; The first hydraulic actuator is used to provide a loading force along a first direction, the first hydraulic actuator is arranged on one side of the axle box shear pad along the first direction, and the output end of the first hydraulic actuator is connected to the constraint assembly; The second hydraulic actuator is used to provide a loading force along a second direction, the second hydraulic actuator is arranged on one side of the axle box shear pad along the second direction, and the output end of the second hydraulic actuator is connected to the constraint assembly; The third hydraulic actuator is used to provide a loading force along a third direction. The third hydraulic actuator is arranged on the top of the loading beam along the third direction. The output end of the third hydraulic actuator is connected to the loading beam.

4. The axle box shear pad thermal-mechanical coupling fatigue test bench for a freight car bogie according to claim 2 or 3, characterized in that: The workbench comprises a first linear guide mechanism and a second linear guide mechanism, the second linear guide mechanism is located on the top of the first linear guide mechanism, and the top of the second linear guide mechanism is provided with the lower heat insulation board, wherein: The first linear guide mechanism is used to release the first direction of freedom of the axle box shear pad; The second linear guide mechanism is used to release the second degree of freedom of the axle box shear pad.

5. The axle box shear pad thermal-mechanical coupling fatigue test bench for a freight car bogie according to claim 1, characterized in that: The restraint assembly comprises an upper restraint plate and a lower restraint plate which are arranged opposite to each other, and the axle box shear pad is clamped between the upper restraint plate and the lower restraint plate.

6. The axle box shear pad thermal-mechanical coupling fatigue test bench for a freight car bogie according to claim 5, characterized in that: Grooves are provided on the surface of the upper constraint plate close to the axle box shear pad and on the surface of the lower constraint plate close to the axle box shear pad. A thermocouple is provided in each of the grooves. Each of the thermocouples is electrically connected to the heating device.

7. The axle box shear pad thermal-mechanical coupling fatigue test bench for a freight car bogie according to claim 1 or 3, characterized in that: The bracket includes a plurality of columns and a cross-shaped beam, the tops of the plurality of columns are connected to the cross-shaped beam, the lower parts of two adjacent columns are respectively installed with the first hydraulic actuator and the second hydraulic actuator, the bottom of the cross-shaped beam is provided with a plurality of the third hydraulic actuators, and the columns are arranged on a base.

8. The axle box shear pad thermal-mechanical coupling fatigue test bench for a freight car bogie according to claim 7, characterized in that: The base is also provided with the workbench.

9. The axle box shear pad thermal-mechanical coupling fatigue test bench for a freight car bogie according to claim 7, characterized in that: Both ends of the first hydraulic actuator and the second hydraulic actuator are connected to the mounting assembly installed on the column and the constraint assembly through ball joints, and both ends of the third hydraulic actuator are connected to the mounting assembly installed on the cross beam and the loading beam through ball joints.

10. The axle box shear pad thermal-mechanical coupling fatigue test bench for a freight car bogie according to claim 7, characterized in that: A third linear guide mechanism is provided on one side corresponding to the two opposite columns, and the two third linear guide mechanisms are respectively connected to two ends of the loading beam.

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