Dynamic Load Distribution of Roller Thread Considering Gear Pair Meshing Excitation

The synchronous meshing of threaded pairs and gear pairs is a typical feature of planetary roller screw transmission. To reveal the dynamic load fluctuation law of the screw pair caused by the meshing excitation of the gear pair and the inertia force generated by the roller rotating around the screw axis, this paper proposed a calculation method for the dynamic load distribution of the screw pair considering the inertia force and the meshing excitation of the gear pair. Firstly, based on the cylindrical collision theory, energy method, and time-varying spring model, the meshing excitation and time-varying meshing stiffness excitation of the gear pair were solved, respectively. Based on the spiral surface equation of the planetary roller screw, the static contact forces on the contact side of the roller screw and the roller nut were solved. Then, the force analysis was conducted on the roller, and the dynamic load distribution law of the screw pair considering the meshing excitation of the gear pair was obtained based on the deformation coordination condition of the screw pair and compared with the calculation results of the dynamic contact finite element model of the screw pair, so as to verify the correctness of the theoretical model. Finally, the paper analyzed the impact of inertia force and gear pair meshing excitation on the dynamic contact force and dynamic load distribution of threaded pairs. The results shows that: inertia force leads to a greater dynamic contact force on the roller nut side than on the roller screw side; when considering the meshing excitation of the gear pair, the contact force on the roller screw side decreases with the increase of the number of threads, while the contact force on the roller nut side increases with the increase of the number of threads; the meshing excitation of the gear pair causes the contact force between the roller screw and the roller nut side thread to fluctuate in the same pattern over time.