Page 48 - CATALOGUE
P. 48
Features of Precision Ball Screw
1. Compared with ACME screws, the drive torque of ball screws is only 1/3
A ball screw assembly is a kind of high precision mechanical transmission part, comprising a ball
screw shaft, a ball nut, steel rolling balls, sealing parts and other components. Due to the steel
balls rolling between screw shaft and ball nut, ball screw assembly can reach a high mechanical
efficiency and only 1/3 of drive torque compared with ACME screws, converting rotary motion
into linear motion and vice versa. Chart 1 and chart 2 below have shown the efficiency comparison
of ball screw and ACME screw.
Chart 1: Efficiency of normal operation Chart 2: Back drive efficiency
( rotary motion - linear motion) (linear motion - rotary motion)
Calculation of lead angle
………………… （1 ）
Β: Lead angle (degree)
Dp: Steel ball diameter (mm)
Ρh: Feed screw lead (mm)
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