Research On The Key Technology Of The Error Analysis Of The Raceway Profile Of The Ball Screw Pair

This paper studies two key techniques of profile error analysis of outer raceway of lead screw and inner raceway of nut.Based on the analysis of helical surface grinding,the establishment method of general precision model for internal and external thread grinder was expounded from two aspects of raceway forming error and contact Angle error of surface error.The raceway forming error model and contact Angle error model are obtained,and the key geometric error terms which have great influence on the profile error are analyzed.The abnormal phenomena of two inner raceway profiles were studied by using normal plane analysis method.The main research contents are as follows:According to the normal shape of raceway of Gothic circular arc and helicoid equation,the raceway forming mechanism of ball screw pair was established based on the contact condition of space surface.At the same time,a raceway forming analysis method based on normal plane is proposed based on the fact that the workpiece and the cutter maintain a fixed relative pose in raceway forming.The error source of raceway forming process is analyzed,and the error source is divided into general machine tool dressing error,tool dressing error and workpiece error according to the difference of error source.According to the coordinate transformation relation,the single variable models of grinding machine error,grinding wheel dressing error and workpiece error are established respectively.The influence of machining parameter error model and workpiece error on the raceway and the influence of dressing error model on the tool were studied.The numerical analysis and prediction were carried out respectively to get the mode of action of each error.The multi-body system theory is studied and the kinematic relationship of internal and external thread grinder is analyzed.Using the homogeneous error matrix,the tool position and attitude of the tool motion chain and the workpiece motion chain were studied,and the general accuracy model was established.The physical meaning of tool dressing error term was analyzed,and multiple tool dressing errors were mapped to multiple substituting geometric errors of virtual axis V,and a grinder accuracy model considering tool dressing error term was established.Secondly,based on the improved precision model of thread grinder and the contact condition formula of raceway forming,the improved contact condition formula considering the error of tool pose was established.The raceway forming error model was established based on the raceway actual and theoretical contact point deviation,and the contact Angle error model was established based on the actual contact point projection.Finally,the global sensitivity analysis method was used to analyze the sensitivity of grinding machine geometric errors affecting the profile,and the influence of linear and angular geometric errors was compared,and the key geometric errors affecting the raceway forming and contact Angle were obtained.The application of the normal plane analysis method for raceway forming was studied,and two kinds of raceway profile anomalies were simulated and verified.The analysis shows that the main reason for the raceway profile error of model 5050 is interference grinding method,which is essentially the phenomenon of tool overcutting raceway.The simulation shows that the tool diameter is an important factor.The phenomenon of raceway edge small area chamfering under the standard grinding method of the inner raceway of model 1610 is analyzed.The simulation results show that the tool upward deviation error is caused.The inner raceway of model 1610 is detected,and the detection results are in good agreement with the simulation results.