| In this paper,the angular contact ball bearing NSK7001AW used in the rotation joint of 3R-CPR pointing mechanism is taken as the research object:Firstly,the main reason for the increase of bearing radial clearance deformation is calculated,based on Hertz contact theory,the relationship between deformation and load of rolling element of angular contact ball bearing is calculated,and the distribution law of radial load on each rolling element of angular contact ball bearing inner ring is obtained,that is F_r=∑Q_i,the relationship between deformation and radial load of each rolling element of bearing is obtained.Based on Stribeck theory,the clearance and deformation of angular contact ball bearing under different compression conditions are calculated,and the relationship between radial load and radial approach of inner and outer rings is obtained.The clearance change of nsk7001aw bearing under the working condition of pointing mechanism is calculated,and the specific measurement method laser speckle method is proposed based on the clearance level.Secondly,the dynamic simulation of the bearing is carried out based on Adams.Taking the number of rolling elements and clearance as variables,the phenomenon of"step runout"of bearing inner ring is observed,and the correctness of theoretical analysis is verified by comparison;based on Ansys Workbench,the static characteristics of multi-body contact of bearing are simulated and analyzed with load and position angle as variables,and the static performance of bearing under different load parameters is obtained.Compared with the results of Hertz theory,the results can be used as one of the ways to verify the correctness of the theory.Then,according to the low-speed and light load conditions of the high-precision spatial parallel pointing mechanism and the measurement principle proposed in the previous paper,an experimental prototype of angular contact ball bearing deformation measurement is designed.The transmission system and sensor detection system of the measurement device are selected.The static structure analysis is carried out where the error may be introduced.The size of the prototype is optimized to ensure the real measurement of the prototype the accuracy of the test results.Finally,the laser speckle measurement optical path is built,and the bearing loading test-bed is assembled to measure the radial clearance of angular contact ball bearing.Through data processing and analysis of the experimental results,the relationship between the fringe spacing of laser speckle method and the measured real displacement is obtained.The deformation characteristics and clearance values of the bearing under different loads are obtained;the radial clearance curves of the bearing under different loads and different position angles are obtained by changing the position angle parameters,and the results are analyzed after eliminating the errors,the bearing deformation is measured indirectly.The theoretical calculation is compared with the simulation and experimental results,which verifies the correctness of each other. |
