Analysis Of The Mechanical Properties And Comprehensive Test Research For Bearing Assembly

The bearing assembly is one of the core components of the spacecraft for attitude control, its mechanical properties and reliability have a direct impact on the spacecraft’s running operation. Four-point contact ball bearing is its core component, the paper mainly studies its axial stiffness, its preload and start-up friction torque characteristics. The main achievements are as follow:Firstly, the axial stiffness of four-point contact ball bearing is tested. CNC machine tool is used to load the bearing, strain type force sensor is used to test the axial force and inductive micrometer is used to test the displacement. The load-displacement curve of bearing can be obtained by processing the data.3sub-samples of four-point contact ball bearing were measured for axial stiffness. The results show that the axial stiffness of the four-point contact ball bearings increases with the axial force, and the greater the absolute value of negative clearance is, the greater the axial stiffness is.Secondly, the preload of the four-point contact ball bearing is tested. The experimental principle is getting the stiffness characteristic curve by testing the axial stiffness for the inner ring of the inner ring split bearing, then looking for its axial preload by looking for the inflection point of the bearing stiffness. The experimental equipment is designed according to experimental principle and the experiment about inner ring split bearing is conducted on CNC machine tool. The preload for the bearing is determined by analyzing the experimental data and looking for the inflection point of the bearing stiffness, which provides a reference for the assembly process.Finally, the experimental program is developed according to the testing task for the start-up friction torque of four-point contact ball bearing and a set of experimental equipment is designed according to the characteristics of bearing assembly. The relationship between tightening torque and axial force can be measured by this experimental equipment, based on which the experiment about the relationship between difference tightening torque and start-up friction torque can be conducted, and the experiment about the relationship between temperature variation and start-up friction torque can be conducted in high and low temperature experiment box. The subsequent experiments can be conducted by the specific experimental equipment, which lays the foundation for grasping the characteristics of the start-up friction for four-point contact ball bearing.