The Analysis Of Low-rigidity Parts Gear Ring Based On Coupled Thermal-mechanical Simulation And The Validation Experiments

Low-rigidity parts are typical difficult-to-machine parts which have complexshape and high appearance coordination demand. The typical parts in high powertransmission system of vehicles, such as the planet carrier, the structure of the wheeland gear ring are the Low-rigidity parts. It is hard to control machining deformationbecause of its low stiffness, high dimensional accuracy, poor manufacturability andthe influence of many factors such as the cutting force, cutting heat, residual stress,clamping force, machine tool vibration. Particularly, interaction between variousfactors makes it harder to control the machining deformation. This article uses themethod of the theoretical analysis, numerical calculation, finite element simulationand experimental verification around cutting performance and machining deformationproblem of gear ring, based on research of cutting force and cutting heat, explore thedeformation rule of the part in the influence of cutting force and cutting heat. Themain research work includes the following aspects:In order to build the Johnson-Cook constitutive model of gear ring, for thematerial of gear ring,20Cr2Ni4, the experiments are carried out. Through theexperiments, measure material performance of this material, study the relationshipbetween stress and strain, determine the model parameters of Johnson-Cook, andbuild the constitutive relation model of the part.Based on the rough machining process of gear ring, study the key problems andkey technologies such as cutting tool and chip contact separation, heat generation andconduction. The thermal coupled model is established, by using the model to do twodimensional orthogonal cutting finite element simulation, analyze the forming processof the chip in the process of machining and its morphology, distribution regularity ofstress, strain and temperature field, and prove the rule of the chip takes the majority ofthe heat, and make the conclusion that the heat will influence the distribution of stress.Based on the two-dimensional cutting simulation, build the coupledthermal-mechanical three dimensional simulation model to simulate thethree-dimensional processing, analysis the distribution rules of stress field andtemperature field. On this basis, simulate the deformation of the gear ring considering temperature and regardless of the temperature field.Finally, analyze of the influence rule of cutting parameters on cutting heat, anddesign experiments to verify the simulation results, prove the reliability of thesimulation model. On this basis, simulate the deflection of the gear ring consideringtemperature and regardless of the temperature field, and make the conclusion that theheat will enlarge machining deformation of ring gear, but the heat will influence littlewhen the temperature ranges in a scope.