Research Of Sticking And Jamming Mechanism Of Thrust Ball Bearing Under Extreme Conditions

The thesis conducts a research on the sticking and jamming phenomenon of ball bearings under the combined action of extreme environment including microgravity, extreme temperature and high vacuum. In this paper, the thrust ball bearing is taken as the research object and the sticking and jamming mechanism thrust of it in the extreme environment has been studied. According to the theoretical results, establish the boundary conditions and multi-body dynamics finite element simulation model of thrust ball bearings and then simulate its startup and operation process.Following the clue of weight loss, the theory research analyses the movements and the strained status of the bearing components in gravity and zero gravity environment, establish that the motion and the strained status of the rolling are essentially different in zero gravity environment against gravity environment, and take the rolling as the research object. The basic theories of dynamics and tribology are used to study the sticking and jamming mechanism of the thrust ball bearing in extreme environment and the conclusions are that when the rolling elements are in the special synthesis environment and the specific area of raceway space, restart again and the torque will increase obviously, which will result in the sticking and jamming phenomenon, however, the emergence of such phenomenon is a very small probability event. According to the theoretical results, establish the boundary conditions and multi-body dynamics finite element simulation model of thrust ball bearings and then simulate its startup and operation process. In several examples, there is1case meeting the above criteria, which verify the results of theoretical research.In order to carry out experimental researches on the bearing in microgravity, a set of test unit and calibration device is presented, in which the microgravity environment is established by using electromagnetic suspension to balance gravity, and the force distribution of steel balls and the retainer are researched through simulation.In this paper, the project of using electromagnetic suspension to balance gravity are put forward. The force distribution of steel balls and the retainer in magnetic field is researched through simulation, and get the distributed regularity of magnetic force and the conditions balancing gravity, which shows that the project is feasible and provides theoretical basis for the design of electromagnetic field.According to the above results, the preliminary design of the electromagnet structure and bearing testing rig is completed. In order to correct the deviation of the calculated magnetic force, the calibration device is designed, and expect that the calibration results will provide a practical basis for the adjustment of the test unit parameters.