Investigation of the precision loss for ball screw raceway based on the modified Archard theory

Abstract

Purpose This paper aims to examine the precision loss of ball screw raceway under different operating conditions and geometry parameters. Design/methodology/approach Based on a new coefficient K’ introduced especially for ball screws to reflect the actual contact condition, the modified Archard theory is applied to ball screws to obtain wear volume of the ball-screw contacts. Thus, the axial precision loss can be defined as the ratio of the wear volume to the contact area. Meanwhile, a novel running bench and a precision-measuring system of ball screws are conducted. Precision variation is obtained and analyzed during the whole life running test, which agrees well with the theoretical values calculated in this paper. Findings For a given rotational speed, the increasing rate of the precision loss rate is high at low axial load and then becomes small with the increasing axial load, whereas for a given axial load, the precision loss rate is proportional to the rotational speed. Besides, the precision loss rate is reduced with the increasing contact angle between a ball and the screw raceway, and is proportional to the helix angle when the angle changes from 1 to 10 degrees. Research limitations/implications The rotational speed used in this experiment is low and the ball screw is of no-load type, although results calculated by the model and Wei’s model seem close when the axial load is high, whether the model built in the paper is applicable to the condition of high rotational speed and preload still needs to be verified in the future work. Practical implications This study provides an accurate model to predict the precision loss of the screw raceway and estimate the remaining life of ball screws, which is significant for better performance of ball screws as well as the computer numerical control machine tools. Originality/value Previous studies on the wear of ball screws mainly focused on the drag torque analysis and mechanical efficiency estimation, and the experiment to verify their theoretical analysis was almost all limited to the test of drag torque or axial rigidity, which is neither sufficient nor persuasive. However, in this paper, the authors proposed a comprehensive wear prediction model which combines the modified Archard wear theory, Hertz contact theory and kinematic theory of ball screws. To the best of the authors’ knowledge, this kind of study has never been reported in the literature. In addition, for the lack of the test bench and high cost of the experiment, the whole life operation test, which is designed and conducted to confirm the model in this paper, has never been reported in literature either.

Optimization Analysis of Structural Parameters for Ball Screw Precision Retention Based on Advanced Neural Fuzzy Network

“…To date, studies on the precision loss of ball screws due to sliding and rolling motion have typically focused on kinematic and static analyses [1][2][3][4][5][6] or creep theory [7,8]. By combining sliding motion analysis with Archard theory [9], a ball screw precision loss model for analyzing sliding motion behavior was previously established [10][11][12][13]. Wei et al [10] investigated wear rates of ball screws under various operating conditions and described the relationship between preload and wear rate.…”

Dynamic axial contact stiffness analysis of position preloaded ball screw mechanism

“…In recent years, with the growth of demand for high precision, high speed, and high durability in CNC machine tools, high performance and reliability have become the most important indexes for ball screws. [2][3][4] In order to eliminate backlash and improve the contact stiffness of the ball screw system, preloaded double-nut structure is usually adopted. The preloading method of double-nut ball screw system can mainly be divided into two categories: constant-pressure preload and position preload.…”

Investigation of the fluctuation of the static axial rigidity for double-nut preloaded ball screws

“…Ball screws, which are widely used in computer numerical control (CNC) machine tools, have a great influence on the dynamic stability and vibration of the feed systems. 1,2 With the continuous increase in the requirement of the speed and load capacity of ball screws, 3 the vibration and other problems caused by poor stiffness are becoming more and more prominent, which seriously affect the positioning accuracy of CNC machine tools. 4,5 According to ISO 3408-3-2006, 6 the fluctuation of the friction torque of preloaded ball screws can be achieved as high as 50% of the initial dynamic preloaded drag torque, which will lead to a great fluctuation in the static rigidity over the whole effective travel.…”