Thermal Characteristics Analysis And Structure Optimization For Spindle Components Of Heavy Duty Milling-boring Machine Tool

NC heavy duty milling-boring machine tool is mainly used for processing theplane and hole of large parts, which is an key equipment in the pillar industries suchas national defense industry, aerospace industry and large engineering machinery,etc. High speed has become an important development trend for NC heavy dut ymilling-boring machine tool, which has significant implications for improving theprocessing precision and efficiency of machine tool. As the core parts of NC heavyduty milling-boring machine tool, spindle components produce significanttemperature rise and thermal deformation in high speed, which directly impact theprocess accuracy and in some severe cases can cause the damage of the machine tool.This thesis is aimed at the analysis of thermal characterstics for spindle componentsof NC heavy duty milling-boring machine tool. A scheme of structure optimizationis proposed in this thesis.The mathematical model of temperature field of machine tool is establishedbasing on heat transfer theory and machine’s thermal characteristics theory. Thecalculation method of the heat of bearing and the thermal boundary conditions ofspindle components are studied. According to the actual working condition, Thefinite element model of temperature for spindle components of NC heavy dut ymilling-boring machine tool is built. The thermal characteristic of spindlecomponents in the speed of1000r/min is analyzed with the finite element model,and the temperature field and the thermal deformation field of spindle componentsare obtained.To inprove the precision of the model, orthogonal testing method is used torevise the convection coefficient of the finite element, according to the experimentalmeasurement and analysis of the key point’s temperature and thermal deformationon Spindle Components of NC Heavy Duty Milling-Boring Machine Tool in thespeed of1000r/min. By comparing the key point’s temperature and thermaldeformation of spindle components gained in the experiment with those in the finiteelement modeling, the accuracy and the applicability to different working conditionsof the finite model revised are checked.With the finite element, the temperature field and thermal deformation field o fspindle components in the speed of2500r/min are predicted and the reasons whichcause the failure of spindle components in high speed are analysed. Basing onanalysis result the finite element, measures of improving the thermal chatacteristicsof spindle components are put forward and structural optimization design isperformed. The thermal characteristics of optimized spindle components structure is analysed by the finite element model, to verify the validity of the optimization.