Ball Screw : Multiple number of balls along screw ditch convert sliding
friction into rolling friction.
Motion of balls along screw ditch : Slippage of instanteneous contact point
between the ball and the screw ditch, due to the twisted geometry, as well
as the effect from the ball circulation mechanism.
2/D Circular Motion : Theoretical approach.
3/D Spiral Motion : Multi-body dynamic simulation.
Evaluation of Friction : Comparative study of friction models.
Evaluation Indices : Smoothness of ball motion.
