| Since precision ball screw used more and more widely in aerospace industry, it is important to research its ultimate bearing capacity and stiffness. The ball loading distribution is the foundation of studying these properties. At present, the ball bearing of ball screw is simply regard as the average distribution. But it is very different from the actual situation. This topic combining with elastic-plastic theory and deformation compatibility condition establish a model to solve the load distribution of the ball screw. And the contact deformation and axial contact stiffness of the ball screw are analyzed based on this research. And some relevant structural parameters are optimized.Firstly, contact characteristics of ball screw under space working condition are analyzed based on Hertz theory. And the calculation formula between Normal load of ball and the elastic-plastic contact deformation is derived. And establish a model to solve the load distribution of the ball screw combining with the deformation compatibility condition. Besides, the influence of Geometric error on the distribution of the load is analyzed. Secondly, the axial stiffness of ball screw and the relationship between the contact angle and the axial load are analyzed according to the model. When the ball screw loaded, contact angle will have a certain amount of increase. The calculation formula of the increase of the contact angle is derived in this paper. At last, the mathematical model which set the maximum axial rigidity of ball screw as the main optimization goal is established combining with the research of the axial stiffness of ball screw. And some relevant structural parameters are optimized. Besides, through the comparison of the results between the theory model and ABAQUS finite element model verify the reliability of the theory. |
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