Inside the spiral pair, there is a

Inside the spiral pair, there is a spiral mechanism of rolling friction, which is called rolling spiral mechanism or ball screw. The feature of this mechanism is that there is a circulation orbit between the screw and the nut, and there is a hard sphere between them, and when the screw rotates, the hard sphere rolls along a spiral orbit and moves the nut straight.According to different circulation methods, it can be divided into two forms: external circulation and internal circulation. The cycle in which the ball constantly contacts the screw during cycling is called the internal cycle. The cycle in which the balls do not come into contact with the screws when returning is called the outer cycle (Fig. 2-2). The outer circulation nut may be provided with a reverser, and when the ball enters the reverser, it is prevented from turning from the return flow path to the opposite side of the track to form a circulation loop.The lateral movement of the manipulator uses a rolling screw drive. The rolling screw mechanism has low friction resistance, high operation sensitivity, and high transmission efficiency, so it can reach 90% or more. The adjustment method can eliminate the gap and has high transmission accuracy.