Drozdenko V. Improving the accuracy of dynamic parameters of a lathe machine of a relocatable spindle unit

The dissertation aims at improving the accuracy of dynamic parameters a lathe machine of a relocatable spindle unit. The main area of the research is formulated based on the analysis of the literature. Constructional features of spindle units are considered and their basic parameters affecting the accuracy are determined. The static and dynamic characteristics of contact connections and features of rotating precision of spindle units are defined. The working processes of machines are studied. A theoretical and experimental study of spatial nonstationary stochastic cutting forces are conducted. The theoretical and experimental study of deformation spindle units under stochastic cutting forces are carried out. Studies of positioning accuracy of spindle unit of lathe machine moved in two coordinates are conducted. The mathematical models of energy processes are used to estimate the basic parameters of the spindle position output. Specific dynamic processes of machine with relocatable spindle unit are studied. Processes are related to the emergence of gyroscopic moments of considerable intensity at the cross-angular fluctuations of rotating spindle. It is shown that the presence of gyroscopic moments leads to the appearance of parametric oscillations in dynamical system of machine with relocatable spindle unit. This leads to lower accuracy and occurrence of resonant vibrations at certain frequencies of spindle rotation. The measures to reduce the intensity of oscillations are proposed, and hence the increase of dynamic precision of lathe machine. The effective design of lathe machine of relocatable spindle unit is developed based on the research results.