Periodic variation of preloading in ball screws

Abstract

The preloading is a main characteristic for the functionality of a ball screw. The path of preloading during operation with no thrust load is an indicator for the actual inner forces, the friction produced by the ball screw and finally for the quality of the unit. Due to manufacturing tolerances the preloading over the useful travel of the ball screw differs from its specified value. However, not only the overall loading of a ball screw varies, but also the local load distribution within the nut. This is expressed by a periodic variation of the internal forces which has an effect on the alignment of the nut and therefore on the uniformity and the motion characteristics of a ball screw feed drive. The following paper deals with the occurrence of these periodic force variations and offers an explanation for this particular phenomenon.

Influence of controller parameters on the life of ball screw feed drives

“…The screw shaft is mounted on a roller pack (4) fixed to a metal support (5). The ball screw assembly, composed of a screw (6) and a nut (7), transforms rotational into linear motion. The nut is fixed to the slide (8), so that the turning of the screw generates a linear movement of the slide, which is mounted on recirculating rolling guides (9) to constrain all degrees of freedom but the desired travel direction.…”

“…The rotary subsystem (A) comprises the motor shaft (1), the ball screw end (2), and the screw rotational inertia (3), which are connected by the torsion spring and damper k 12 , comprising the stiffness and damping of the motor shaft and the elastic joint, and k 23 , comprising the ball screw end and the screw. The axial subsystem (B) is composed of the screw axial inertia (4), the ball screw coupling (5), the ball nut (6), and the slide (7). Linear springs and dampers axially connect these elements in series: k 04 comprises the axial support, the bearing pack, and the screw; k 56 represents the system formed by the ball tracks on the screw and nut and the balls, whereas k 67 represents the flange that connects the ball nut to the slide.…”

“…Other authors studied some of these effects not considered in ISO that affect operating behavior of a ball screw, such as variable loads caused by misalignments due to manufacturing tolerances, 7 failure caused by impacts between the steel balls and the returning tube, 8 and optimal lubrication. 9 This work presents a theoretical analysis of the influence of the control parameters on the machine tool that affect the dynamics of the axis and the life of the ball screw as well, through a simulation approach with nominal fatigue life calculation.…”

Dynamic modeling and analysis of the nut-direct drive system

“…Ball screw feed system is widely used in the industrial production due to its large rigidity, high efficiency, and lower cost. 1,2 Dynamic characteristic of ball screw feed system is the significant influence on the positioning precision, machining performance, and vibration characteristic of machine tools. [3][4][5] In recent years, many researchers have studied the dynamic characteristics of ball screw feed systems due to their industrial significance.…”

Testing of Efficiency and Dynamic Effects of a Drive System With a Lead Screw

“…A methodology for stress state limit recovering in return system is developed in paper [1]. The author of the article [5] analysed the occurrence of the periodic force variations and explained this phenomenon. The authors of the publication [16] presented a high-frequency dynamic model of a ball screw drive.…”