Key Technology And Analysis Of Ball Screw Pair Helical Raceway Inspection

The subject of this article relies on the National Science and Technology Major Project "Functional Component Test and Test Common Technology Research and Ability Establishment(2016ZX04004007)".Through preliminary investigation,it was found that the key performances of the ball screw such as friction torque fluctuations,stiffness,and positioning accuracy are largely affected by the accuracy of the ball and raceway,but there are few studies on the relationship between ball screw performance and ball and raceway errors in the recent researches.Based on this background,this article has conducted in-depth theoretical and experimental research on the factors affecting the key performance of the ball screw and the measurement of the raceway error of the ball screw.The specific research content is as follows:A load distribution model of ball screw consisted of ball and raceway errors is established.Different from the previous view that the force is evenly applied on the ball in a ball screw,this paper establishes a calculation model of the load distribution of the ball screw based on the deformation of the screw and the nut,and further analyzes the effect of the accuracy of the ball and raceway error on load distribution.Through the simulation analysis of the sample,it is found that: the machining accuracy of the ball determines the fluctuation of the load and friction torque of the ball screw;among all the raceway errors,the lead error caused by the temperature rise in the screw process has the greatest influence on the load distribution of ball screw.By controlling the temperature rise in the screw process within 4 ° ? 5 °,the ball screw auxiliary load distribution can be more stable and rigid.Based on the principle of laser triangulation ranging,a spiral screw raceway measurement scheme for the ball screw is designed.Comprehensive consideration of the raceway measurement distance,measurement accuracy and other factors,this paper accomplishes the measurement sensor selection and tooling design.Because the inner diameter of the nut is much smaller than the size of the sensor,the sensor cannot directly measure the inner raceway of the nut.This article uses optical instruments to re-plan the path of the measurement laser.The measurement errors of the screw nut raceway detection scheme are analysed from three aspects: sensor errors,structural errors,and installation errors.The results show that the installation errors have the greatest influence on the accuracy of the measurement results.Several pre-experiments are designed to compensate for installation errors,and accuracy tests are performed on the ball screw nut raceway.The geometric model of the ball screw auxiliary raceway profile was established,and the geometric model was used to quantitatively analyze the errors of the common axial section data processing methods.The results show that shaft section has different left and right radii,and the radius of the arc raceway on the shaft section is larger than the radius of the arc raceway on the the normal section,so the normal section parameters cannot be obtained by fitting the axial section data directly.In addition,the cosine conversion method commonly used in engineering has an error of more than 1.5 ?m.An accurate axis normal transformation algorithm is proposed and verified by geometric model.The proposed algorithm is used to process the measurement data,and the data processing results are compared and analyzed.