Contact Analysis of Thread Pairs in a Planetary Roller Screw Based on Finite Element Method

This paper investigates the contact characteristics of the thread pairs in the planetary roller screw mechanism. Firstly, the analytical model of thread contact based on Hertz contact theory is established. Secondly, the contact models of the screw and roller threads and of the roller and nut threads based on FE method are developed. The correctness of the numerical results is verified via the comparison with analytical results, the relative error between the two sets of results is less than or equal to 2%. Lastly, according to FE model, the contact state, contact positions and contact stresses of thread pairs at the screw-roller interface and at the roller-nut interface are derived.