screw

　　The bearing capacity of rolling screw mainly depends on the radius of curvature, the number of contact points, the hardness and smoothness of the contact surface.

　　Under the condition of the same contact surface hardness, smoothness and precision, roller lead screw has more contact points than ball screw, and the radius of curvature of the envelope circle of roller contact surface is far greater than that of ball screw steel ball, which determines that roller lead screw has higher bearing capacity than ordinary ball screw.

According to the different structure, roller screw pair can be divided into planetary roller screw pair and circular roller screw pair. There are essential differences in the operation mode of the two rollers: the roller of the planetary roller screw pair has no axial movement relative to the nut during the revolution and rotation, while the circular roller screw pair has the axial circular movement relative to the nut except for the revolution and rotation movement.