Characteristic Analysis Of Hydrostatic Spindle Of High Precision CNC Lathe

At present, as the rapid development of science and technology, machine tool,which is the most fundamental and important production equipment in industrial fields, therefore, the high speed, high precision and high stability to machine tool is the necessity direction to develop. Spindle is one of the most important parts of machine tool, it's static and dynamic characteristics is directly related to the machining accuracy and stability of the machine tools. The performance of machine tool spindle system is directly affects the whole machine's performance index. Therefore, analyzeing the characterize of the spindle, exploreing the analysis methods and means on the characteristics of machine tool spindle has very important practical significance.This topic is one sub-projiect of the science project, "high precision CNC lathe industrialization", in Yunnan province. Contrapose the static characteristic and dynamic characteristic requirements of CNC lathe spindle in design phase, high precision CNC lathe spindle's characteristics were analyzed and researched using finite element method.The whole preliminary design fo the spindle system was did in the paper: spindle motor was used to drive the spindle system directly to improve the precision and stability of the drive shaft; using three support structure on support layout; using rolling bearing on auxiliary support; using hydrostatic bearings on main supporting, and thrust hydrostatic bearing located in both sidesof the front radial hydrostatic bearing; selected material types and structural parameter of the spindle.Based on the subject request, we designed front and bake radial double-side film throttling feedback liquid hydrostatic bearing and thrust double-side film throttling feedback liquid hydrostatic bearing. Calculated the structure sizes, performance parameters of the Film throttle device and the bearings'capacity and rigidity, flow and pump power and so on.With ANSYS,we established the finite element modeling of spindle in the paper. The kye point and difficult is how to simulate the spindle bearings; Then analysised the static characteristics of the spindle after completed the spindle's finite element modeling,gain the value of stress, strain and all kinds of rigidity of the spindle in the normal working conditions.The first 16 order modes of the spindle are calculated with ANSYS software, and the first six critical speeds were calculated basised on mode analysis; Analysed the bearings'rigidity edffection on the spindle's inherent frequency, get the graph between effect of spindle each bearing rigidity of the spindle and the natural frequency without damping of the spindle; Expounds the theory and method of harmonic response analysis'in mechanical structure analysis with ANSYS, analyzed harmonic response of the spindle at the existing stiffness. This work has realistic significance in improving the CNC lathe's performance index,guidanceing the design and retrofit on high precision CNC lathe, what is more the work of the paper has guiding significancehas in structure analysis using ANSYS.