Analysis And Research On Load Distribution And Dynamic Characteristics Of Standard Planetary Roller Screw Pair

The excellent bearing performance of planetary roller screw has attracted wide attention in the field of aeronautics and Astronautics.Compared with the traditional ball screw pair,the planetary ball screw pair has the advantages of compact structure and long service life.However,there are still some disadvantages such as uneven load distribution and low transmission efficiency,which seriously restrict its practical application.In this paper,the influence of the bending deformation of the roller,the screw thread error and the assembly error on the load distribution of the standard planetary roller screw pair is analyzed,the load optimization,axial load difference,dynamic characteristics and transmission efficiency of the rollers are studied theoretically and experimentally.In this paper,a load distribution calculation method for the standard planetary roller screw pair is presented,which takes into account the bending deformation of the roller.Based on the meshing characteristics of the screw surface and the load distribution calculation method mentioned above,the axial load distribution calculation model of each roller is established.Secondly,considering the structure parameters of the planetary roller lead screw,an optimization design model is established,which takes the load uniform distribution as the objective and the thread strength as the constraint.In order to improve the load-bearing capacity of planetary roller screw pairs,the effects of screw thread error and assembly error on load distribution of planetary roller screw pairs were analyzed and studied.The dynamic equation of the planetary roller screw is established by the simplified model,and the relationship between the number of rollers and the number of threads and the natural frequency of the system is obtained.Based on the principle of Tribology,the transmission efficiency formula of planetary roller screw was deduced,and the influence of the axial load of the screw on the transmission efficiency of planetary roller screw was analyzed.The study of this paper is of great significance to the further study of improving the bearing capacity and transmission efficiency of planetary roller screw pairs.