Ball screw has balls whose distance in between is kept small at about one-twentieth of diameter of balls

摘要

The thread grooves (2a,3a) of a screw shaft (2) and a nut (3) correspond to each other when the screw shaft and nut are screwed together, forming a spiral ball roll path (6) along which balls (4) are arranged. The variation in the spacing between the balls due to the rolling of the balls is kept small at about one-twentieth of the diameter of the balls.