Precision design of ball screw:

The lead of a ball screw refers to the distance traveled by the nut after one rotation.

Ball screw lead accuracy: The lead accuracy of precision ball screw (C0-C5 level) is based on JIS specifications and specified by four characteristic item markings (E, e, e300, e2 π). The definitions and allowable values of each characteristic are shown in the figure:

If there is a cumulative lead error between the ball screw C7 and C10, the allowable error value of 300mm within the effective length of the screw is specified in Figure 3.3 e300, which is 0.05mm and 0.21mm respectively

Explanation of terms for lead curve of ball screw:

T+E: Accumulate represents the lead as a straight line, indicating the tendency of accumulated lead over time. This is calculated using the least squares method based on the data obtained from laser detection.

P: Allowable value.

A: Actual measurement value

T: Accumulated standard lead specifies the target value, which is the error obtained by subtracting the accumulated common lead from the accumulated standard lead within the effective thread range. Simultaneously consider factors such as thermal expansion and elastic deformation during the operation of the ball screw. And the accumulated positive and negative directions should be corrected in advance. And sequentially produce ball screws. This value is determined based on actual circumstances or experience.

E: Accumulate the error representing the lead. Accumulated represents the difference between the lead and the accumulated benchmark lead, which can be positive or negative.

e: Change to a maximum width of 300mm within the effective thread length range.

E300: Take a maximum width of 300mm within the effective thread length range of the screw.

E2 π: The maximum width of the difference between the measured value and the reference value of the axial rotation of the screw corresponding to any rotation angle within the range of one rotation of the ball screw.