Friction pair disaster experiment device based on micro-particle space tribology

Abstract

A friction pair disaster experiment device based on micro particle space tribology comprises a motor, a torque sensor, a working shaft, a bearing, a bearing seat, a sealing end cover, a cooling copper plate, an air inlet pipeline and an air return pipeline, an output shaft of the motor is fixedly connected with the torque sensor, and the output shaft of the torque sensor is connected with the working shaft through a coupler. The two bearings and the sealing end cover are arranged on the working shaft through a bearing seat; the two cooling copper plates are respectively fixed on the left side and the right side of the bearing seat; a cooling flow channel is arranged in each cooling copper plate, the air inlet pipeline is connected with a cooling flow channel inlet of the cooling copper plate, and the air return pipeline is connected with a cooling flow channel outlet of the cooling copper plate. The bearing disasters experiment device is used for carrying out bearing disasters experiment on trace micro particles, is suitable for space tribology research of particle diameter micron level and particle mass milligram level, and effectively solves the problem that a large number of destructive experiments cannot be carried out due to extremely precious lunar soil samples. The invention relates to the technical field of lunar dust disasters of bearings and sealing pairs thereof.

Description

Technical Field

[0001] This invention relates to the field of bearing and sealing pair dust disaster technology, specifically to an experimental device for the disaster of friction pairs based on microparticle spatial tribology. Background Technology

[0002] Lunar regolith differs significantly from Earth's soil. Its particles are sharp, highly charged, and exhibit unique tribological properties under vacuum and microgravity conditions. These properties directly affect the mobility of lunar probes, the durability of mechanical components, and the long-term reliable operation of equipment. For example, the frictional behavior of a lunar rover's wheels or robotic arm with the lunar regolith determines its mobility, energy consumption, and wear life. In-depth research into the friction-wear mechanisms of lunar regolith can provide a scientific basis for dustproof sealing technologies and the design of wear-resistant materials, thereby extending the lifespan of the probe.

[0003] From a broader perspective, the findings of lunar regolith tribology are not only applicable to the Moon but can also provide a reference for exploration missions to Mars or other atmosphereless celestial bodies. The regolith layers of different planetary surfaces possess their own frictional properties, and lunar regolith, as the most thoroughly studied extraterrestrial soil, offers tribological insights that can help scientists analyze the surface environments of other celestial bodies.

[0004] The equipment for lunar soil tribology research is the foundation of lunar soil research. Building a typical friction pair catastrophe test bench based on microparticle spatial tribology research can conduct catastrophe experiments on a series of typical friction pairs such as lunar dust on bearings and sealing pairs, study the catastrophe threshold of lunar dust on friction pairs and the distribution state of particles after catastrophe, and analyze the catastrophe mechanism of lunar dust.

[0005] Due to the scarcity and preciousness of lunar regolith, current research mainly focuses on compositional analysis and non-destructive analysis methods such as 3DCT to understand its evolutionary mechanisms and the historical changes in the lunar environment. However, research on the engineering and tribological properties of lunar regolith particles remains relatively lacking, and experiments on the catastrophic transformation of typical friction pairs in a space environment using microparticles are almost entirely absent. This invention provides specific research equipment to address the current lack of research on lunar regolith tribology, enabling the conduct of microparticle catastrophic transformation experiments of typical friction pairs in a space environment, thus filling this gap.

[0006] Previous studies have shown that lunar dust particles have highly irregular morphologies, most with sharp edges. Existing in a high vacuum, these particles lack the lubricating effect of an adsorption layer between them (and other surfaces), making them highly susceptible to adhesion, cold welding, and dry friction. Therefore, lunar dust possesses an extremely strong abrasive ability, easily causing wear on the surfaces of moving parts in mechanisms. Bearings, as indispensable components in lunar exploration mechanisms, are also severely affected. Therefore, it is urgent to address the problem of lunar dust catastrophism in bearings and their sealing surfaces within lunar exploration mechanisms, to study the causes and processes of lunar dust catastrophism, to deduce the catastrophic mechanism of lunar dust on bearings, and to analyze the influencing factors of lunar dust damage to bearings, providing new insights into solving the problem of lunar dust catastrophism in bearings. Summary of the Invention

[0007] To address the aforementioned technical problems in the prior art, this invention proposes a method based on microparticle spatial tribology. Experimental apparatus for the disaster-causing of friction pairs.

[0008] The technical solution adopted by the present invention to solve the above problems is as follows: This invention provides a cataclysmic experimental device for friction pairs based on microparticle space tribology, comprising: The bearing drive mechanism includes a motor, a torque sensor, a working shaft, two bearings, bearing housings, and bearing sealing end caps. The motor is fixed to one side of the upper surface of the base via a mounting bracket. The output shaft of the motor is fixedly connected to the torque sensor, which is fixed to the base via a sensor bracket. The output shaft of the torque sensor is connected to the working shaft via a coupling. The two bearings are mounted on the working shaft via bearing housings. Each bearing has a bearing sealing end cap on its axial outer side. The two bearing sealing end caps are respectively fixedly installed on the outer walls of the two sides of the bearing housing by bolts.

[0009] The temperature control mechanism includes a cooling copper plate, an air inlet pipe, and a return air pipe. Two cooling copper plates are fixedly connected to the left and right sides of the bearing housing, respectively. Each cooling copper plate has a cooling channel inside. The air inlet pipe is connected to the cooling channel inlet of one cooling copper plate. The channel outlet of the cooling copper plate is connected to the cooling channel inlet of the other cooling copper plate through a connecting pipe. The cooling channel outlet of the cooling copper plate is connected to the return air pipe.

[0010] Furthermore, the experimental device for the catastrophe of friction pairs based on microparticle spatial tribology also includes a loading mechanism, which comprises a radial loading unit and an axial loading unit.

[0011] Furthermore, the radial loading unit includes a weight pan and weights. The lower end of the weight pan passes through the top cover of the aluminum profile frame and is opposite to the protruding end of the working shaft. By adding weights to the weight pan, a radial load is applied to the working shaft.

[0012] Furthermore, the load range of the radial loading unit is 0-100N.

[0013] Furthermore, the axial loading unit includes a shim with adjustable thickness, which is placed between the bearing sealing end cap and the bearing. The axial load on the bearing is changed by changing the thickness of the shim.

[0014] Furthermore, the thickness of the gasket in the axial loading unit is 0-0.8mm. Furthermore, cooling circuits are provided on the left and right side walls of the bearing housing, and cooling circuits matching the bearing housing are provided on the inner side wall of the cooling copper plate. The two cooling copper plates are welded to the two sides of the bearing housing to form a complete cooling channel.

[0015] Furthermore, a heat insulation cover is provided on the outside of the bearing housing and the cooling copper plate.

[0016] Furthermore, the heat insulation cover is made of polytetrafluoroethylene.

[0017] Furthermore, the top of the bearing housing is provided with a mounting hole for mounting a temperature sensor.

[0018] The beneficial effects of this invention are: 1. This invention relates to catastrophic experiments on bearings using trace microparticles, applicable to space tribology research with particle diameters in the micrometer range and particle masses in the milligram range. It effectively solves the problem of the inability to conduct large-scale destructive experiments due to the extreme preciousness of lunar soil samples, meeting the current needs of my country's lunar exploration program for lunar soil tribology research and filling a gap in this field.

[0019] 2. This invention employs a cooling method that uses cold nitrogen gas for convective heat exchange via a dedicated cooling copper plate, combined with a PTFE heat shield to form a highly efficient local temperature control system. This system stabilizes the working area temperature within the required experimental temperature range, significantly reduces energy consumption, saves nitrogen gas usage, and improves cooling efficiency and stability.

[0020] 3. The present invention uses weights for radial loading and shims of different thicknesses for axial loading. By simulating the forces experienced by the device during movement through radial and axial loading, the effect of microparticles entering the bearing on the bearing under different working conditions can be determined. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is an isometric view of the overall structure of the present invention; Figure 3 yes Figure 2 A sectional view; Figure 4 This is a schematic diagram of the bearing housing of the present invention; Figure 5 This is a schematic diagram of the temperature control mechanism of the present invention; Figure 6 This is a schematic diagram illustrating the environmental simulation principle of the present invention. Detailed Implementation

[0022] Combination Figure 1 This embodiment describes a tribological experimental device for friction pairs based on microparticle spatial tribology, comprising a motor 1, a torque sensor 2, a working shaft 3, two bearings 4, bearing seats 5, bearing sealing end caps 6, a base 7, a cooling copper plate 8, connecting pipes 9, a flange 10, a heat insulation cover 11, a first coupling 12, and a second coupling 13. Motor 1 is a vacuum servo motor, mounted on one side of the upper surface of base 7 via mounting bracket 1-1. The output end of motor 1 is fixedly connected to torque sensor 2 via first coupling 12. Torque sensor 2 is fixed on base 7 via sensor bracket 2-1, located on one side of motor 1. The output shaft of torque sensor 2 is fixed to working shaft 3 via second coupling 13. Working shaft 3 has a shoulder, with a bearing 4 at each end of the shoulder. The two bearings 4 are connected to working shaft 3 via bearing seats 5. The two bearings 4 are installed in bearing seats (made of copper) 5 and support working shaft 3. The bearing seats 5 have bearing mounting holes for installing the two bearings 4. Each bearing 4 has a bearing sealing end cap 6 on its axial outer side. The two bearing sealing end caps 6 are respectively installed on the front and rear sides of bearing seats 5 and fixed with bolts. Lunar dust particles are immersed in grease and added to bearings 4 and sealing surfaces. As the working shaft rotates, bearings 4 and sealing surfaces are worn by lunar dust particles, causing changes in their working state and performance, and resulting in changes in the torque of shaft rotation. The working shaft 3 is driven to rotate by a servo motor, and the torque change on the working shaft 3 is monitored by a torque sensor 2.

[0023] Preferably, the first coupling 12 and the second coupling 13 are spring couplings.

[0024] In some embodiments, the top of the bearing housing 5 is provided with a mounting hole 5-1 for mounting a temperature sensor, and each bearing 4 is provided with a corresponding mounting hole 5-1 for mounting a temperature sensor at its upper position, so that the temperature of the working area can be monitored in real time by the temperature sensor.

[0025] Cooling circuits are provided on the left and right side walls of the bearing housing 5 (milled out on the side walls, preferably serpentine circuits). Cooling circuits matching the bearing housing 5 are provided on the inner side walls of the two cooling copper plates 8. The two cooling copper plates 8 are welded to the two sides of the bearing housing 5 to form a complete cooling channel. Both the intake pipe 9 and the return pipe 10 are made of stainless steel. After passing through the heat insulation cover 11, the intake pipe 9 is connected to the cooling channel inlet of the cooling copper plate 8 on one side. The cooling channel outlet of the cooling copper plate 8 is connected to the cooling channel inlet of the cooling copper plate 8 on the other side through the connecting pipe 8-1. The return pipe 10 passes through the heat insulation cover 11 and is connected to the cooling channel outlet of the cooling copper plate on the other side. The ends of the intake pipe 9 and the return pipe 10 are connected with flanges.

[0026] A heat shield 11 covers the bearing housing 5 and the cooling copper plate 8. The heat shield 11 has through holes for the intake pipe 9 and the return pipe 10 to pass through. The heat shield 11 is preferably made of polytetrafluoroethylene (PTFE) to insulate against temperature and ensure stable temperature in the working area. Thus, after the cold nitrogen gas is delivered through the intake pipe 9 to the flow channels of the two cooling copper plates 8, it fully cools the bearing housing before being discharged through the return pipe 10.

[0027] In some embodiments, a tribological experimental apparatus for sabotaging friction pairs based on microparticle space tribology further includes a loading mechanism, which comprises a radial loading unit and an axial loading unit. The radial loading unit includes a weight pan 14 and weights 15. The lower end of the weight pan 14 passes through the top cover of the aluminum profile frame 16 and is opposite to the extended end of the working shaft 3. By adding weights 15 to the weight pan 14, a radial load is applied to the working shaft 3. Since it is a shaft end load, the load will apply an off-center load to the bearing 4, so the radial load should not be too large, and the load size is 0-100N. The axial loading unit includes an adjustable-thickness shim, which is placed between the bearing sealing end cover 6 and the bearing 4. The axial load on the bearing 4 is changed by changing the thickness of the shim. The thickness of the shim is adjustable from 0-0.8mm. By applying radial and axial loads, the effect of microparticles entering the bearing on the bearing under different working conditions can be determined.

[0028] Example: When studying materials in a space environment, it is crucial to consider the differences between the space environment and the terrestrial environment. To ensure the accuracy and reliability of the experiment, the experimental apparatus of this invention is placed in a vacuum environment simulation device, and the temperature during the experiment is strictly controlled. To meet this requirement, the vacuum environment and temperature control system are designed, and the environmental principles are as follows: Figure 6 As shown, An AS200 gas mass flow controller is used to control the flow of nitrogen into the liquid nitrogen tank for cooling. The cooled nitrogen then flows through the inlet pipe 9, through the vacuum chamber wall, and directly into the cooling copper plate to cool the experimental working area. It is then discharged from the vacuum chamber through the outlet pipe. A temperature sensor and the AS200 gas mass flow controller form a closed-loop control system, ensuring the temperature is maintained within ±1℃ of the set value. The top of the bearing housing 5 has a mounting hole 5-1 for installing a temperature sensor, which monitors the working area temperature in real time.

[0029] Taking the simulated lunar dust catastrophic experiment of the R6701-2Z deep groove ball bearing as an example, the specific experimental process is as follows: 1. Sample preparation: Thoroughly clean the bearing and its matching sealing end cap to remove rust-preventive oil and other contaminants, and then dry them. Use a precision balance to weigh out a fixed amount of Madison N-type vacuum cryogenic grease and simulated lunar dust particles, mix them thoroughly according to the predetermined mass ratio, and then fill the mixture into the bearing.

[0030] 2. Installation and Sealing: Install the prepared bearing-seal pair into the bearing housing 5 of the experimental apparatus and connect the working shaft 3. Check all pipeline interfaces and door seals to ensure good system airtightness and no air or liquid leaks.

[0031] 3. Set the operating conditions of bearing 4 and bearing sealing end cover 6: Add a predetermined number of weights 15 into the weight pan 14 to set the radial load of the bearing; select a shim of appropriate thickness and place it between bearing 4 and bearing sealing end cover 6 to set the axial load of the bearing; control the servo motor to set the operating speed of the bearing and sealing pair.

[0032] 4. Vacuuming and Cooling: Close the vacuum chamber door, start the vacuum pumping system, and pump the pressure inside the vacuum chamber to 10. -3 Below Pa. After the vacuum level reaches the experimental requirements, start the temperature control system. Set the target temperature to -120℃ in the control software. The system will automatically turn on the AS200 gas mass flow controller to introduce cold nitrogen into the cooling circuit. After the temperature sensor shows that the working area temperature has stabilized at (-120 ± 1)℃, maintain this state for 30 minutes to ensure uniform temperature across the entire friction pair.

[0033] 5. Experimental Operation: Start servo motor 1 and set the working shaft 3 to run at a predetermined speed. The experiment lasts for 3 hours, during which the computer data acquisition system records the torque data transmitted by torque sensor 2, the vibration signal from the vibration sensor, and the temperature data in real time.

[0034] 6. Post-Experiment Analysis: After the experiment, the motor, temperature control system, and vacuum system were shut down sequentially, and the vacuum inside the chamber was broken. The bearing samples after the experiment were taken out, numbered, packaged, and the corresponding records were made for the left and right bearings. Subsequently, the severely worn areas of the inner and outer rings and balls of the bearings were observed and recorded under a microscope and white light interferometer; the severely worn areas were observed and the damage was recorded using a scanning electron microscope; finally, the grease in the right bearing was taken for chemical composition analysis to comprehensively assess the degree and mechanism of lunar dust catastrophism.

[0035] This experimental setup is designed for catastrophic experiments on typical friction pairs using minute amounts of microparticles. It is suitable for space tribology research involving particles with diameters in the micrometer range and masses in the milligram range. The relevant technical specifications are shown in the table below. It meets the current needs of my country's lunar exploration program for lunar soil tribology research, filling a gap in this field.

[0036] Table 1. Main Technical Specifications of Typical Friction Pair Disaster Experimental Platform

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent substitutions, and improvements made to the above embodiments without departing from the scope of the present invention, based on the technical essence of the present invention and within the spirit and principles of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A catastrophe experimental device for friction pairs based on microparticle spatial tribology, characterized in that, include: The bearing drive mechanism includes a motor (1), a torque sensor (2), a working shaft (3), two bearings (4), a bearing housing (5), and a bearing sealing end cover (6). The motor (1) is fixed to one side of the upper surface of the base (7) by a mounting bracket (1-1). The output shaft of the motor (1) is fixedly connected to the torque sensor (2). The torque sensor (2) is fixed to the base (7) by a sensor bracket (2-1). The output shaft of the torque sensor (2) is connected to the working shaft (3) by a coupling. The two bearings (4) are mounted on the working shaft (3) by the bearing housing (5). Each bearing (4) has a bearing sealing end cover (6) on its axial outer side. The two bearing sealing end covers (6) are fixedly mounted on the outer walls of the two sides of the bearing housing (5). The temperature control mechanism includes a cooling copper plate (8), an air inlet pipe (9), and a return air pipe (10). The two cooling copper plates (8) are fixedly connected to the left and right sides of the bearing seat (5), respectively. Each cooling copper plate (8) has a cooling channel inside. The air inlet pipe (9) is connected to the cooling channel inlet of one side of the cooling copper plate (8). The channel outlet of the cooling copper plate (8) is connected to the cooling channel inlet of the other side of the cooling copper plate (8) through a connecting pipe (8-1). The cooling channel outlet of the cooling copper plate (8) is connected to the return air pipe (10).

2. The experimental device for catastropheization of friction pairs based on microparticle spatial tribology according to claim 1, characterized in that, The experimental device for the catastrophe of friction pairs based on microparticle space tribology also includes a loading mechanism, which comprises a radial loading unit and an axial loading unit.

3. The experimental device for catastropheization of friction pairs based on microparticle spatial tribology according to claim 2, characterized in that, The radial loading unit includes a weight pan (14) and weights (15). The lower end of the weight pan (14) passes through the top cover of the aluminum profile frame (16) and is opposite to the protruding end of the working shaft (3). By adding weights (15) to the weight pan (14), a radial load is applied to the working shaft (3).

4. The experimental device for the catastrophe of friction pairs based on microparticle spatial tribology according to claim 31, characterized in that, The load range of the radial loading unit is 0-100N.

5. The experimental device for catastropheization of friction pairs based on microparticle spatial tribology according to claim 4, characterized in that, The axial loading unit includes a shim with adjustable thickness, which is placed between the bearing sealing end cap (6) and the bearing (4). The axial load on the bearing (4) is changed by changing the thickness of the shim.

6. The experimental device for the catastropheization of friction pairs based on microparticle spatial tribology according to claim 5, characterized in that, The thickness of the gasket in the axial loading unit is 0-0.8mm.

7. The experimental device for catastropheization of friction pairs based on microparticle spatial tribology according to claim 6, characterized in that, The left and right side walls of the bearing housing (5) are respectively provided with cooling circuits, and the inner side wall of the cooling copper plate (8) is provided with a cooling circuit that matches the bearing housing (5). The two cooling copper plates (8) are respectively welded to the two sides of the bearing housing (5) to form a complete cooling channel.

8. The experimental device for catastropheization of friction pairs based on microparticle spatial tribology according to claim 7, characterized in that, A heat shield (11) is provided on the outside of the bearing housing (5) and the cooling copper plate (8).

9. The experimental device for catastropheization of friction pairs based on microparticle spatial tribology according to claim 8, characterized in that, The heat insulation cover (11) is made of polytetrafluoroethylene.

10. The experimental device for catastropheization of friction pairs based on microparticle spatial tribology according to claim 9, characterized in that, The bearing housing (5) has a mounting hole (5-1) on its top for mounting a temperature sensor.

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