Analysis And Structural Optimization On Thermal Characteristics Of Spindle System Of ADGM NC Lath

ADGM NC lathe is the main research product, which is from the sub-topics ofNational Science and Technology Major Project:“High-end CNC machine tools andmanufacturing equipment”(2012ZX04005-021). Thermal characteristics of the spindlesystem composed of headstock and motorized spindle is analyzed and optimized toreducing the spindle thermal deformation and improving the processing accuracy ofthe NC lathe.The mathematical model for calculating the motor and bearing heat is built byanalyzing the structure and operational characteristics of the spindle system. Themathematical model of the convective heat transfer coefficient in each part of thespindle system with the cooling water, ambient air and lubricant are established basedon heat transfer theory.A model of heat transfer among support system of the spindle system isestablished based on thermal network method. Temperature distribution of the spindlesystem is tested at various working velocities and loads, and then through finiteelement software to validate the model. The results show that the error is less than4.5%between simulation result and calculation result. It shows that the establishedmodel of temperature field is reliable.Thermal-structural coupling analysis of the spindle system is carried out,meanwhile, the thermal deformation of the spindle system in the highest speed iscalculated. Five kinds of headstock design programs is proposed, and on the basis ofthermal deformation analysis of the above programs, the better program is determined.Based on the Fuzzy comprehensive evaluation method, optimization design ofheadstock is put forward. Setting wall thickness, the thickness of ribs, ribs spacing andribs location for design variables, and minimum of radial run-out, face run-out of thespindle and headstock quality for target variables, optimization design is carried out.The radial run-out, face run-out of the spindle and headstock quality are respectively decreased by2.07%,2.24%and7.04%compared with the values before optimizing.Dynamic characteristics of the optimized headstock is analyzed, the results show thatthe dynamic performances of the optimized headstock can still meet the requirements.This research work has provided support for design of ADGM NC lathe.