Analytical and experimental of planetary roller screw axial stiffness

In order to solve the problem of poor accuracy of planetary roller screw, a new type of axial stiffness model is established. This model is based on differential geometry and Hertz contact theory and improves the accuracy of static and dynamic analysis. We simulate the thread load distribution under different load. We also analyzed the roller deformation under different eccentricity. The study of effect on axial stiffness of contact angle and roller number shows that the axial stiffness increases with thread contact angle and roller number. Under same load condition, the growth rate of axial stiffness increases with the contact angle and roller number. An experiment is established to verify the stiffness model. The experiment result shows that the maximum error between the new model result and experiment result is 6.41% under heavy load condition which proves the accuracy of the new axial stiffness model.