Research On Accuracy Improvement Of Tooth Shape In Thin Wall Helical Ring

Thin-walled helical gear ring is a special gear power transmission mechanism used in planetary gear reducer.It is also widely used in some engineering machinery fields,such as excavators,armored vehicles and other reducers.The main structural characteristics of thin-walled helical ring gear are that the thickness of the ring gear is different from its own diameter and axial dimension,and because the ring gear is mostly designed as thin-walled parts,its rigidity is poor.When clamping,the deformation will occur due to the clamping force.During machining,the vibration and heat of cutting force generated by cutting tool and workpiece will also lead to the deformation of the part,and the clamping force and cutting force of the workpiece will also lead to the deformation of the part.The combined effect of cutting heat has a great influence on the dimension accuracy,tooth profile accuracy and surface roughness of the machined parts.In order to solve the problem of inadequate occlusion,high noise,violent vibration and low efficiency of transmission caused by the low accuracy of gear ring profile on planetary reducer used in a special vehicle,this paper studies.Firstly,according to the tooth profile error distortion in the existing tooth profile inspection report,the main error factor is the improper clamping method.According to the analysis of the change law caused by the existing clamping mode,the theoretical change law is solved by Caskilyano's theorem,virtual displacement principle and unit load method.At the same time,the actual deformation law is obtained by the finite element simulation.According to the actual deformation law and clamping conditions,the clamp applied to the actual processing field is designed,and the theoretical and finite element simulation of the designed clamp is carried out.True verification.Secondly,according to another reason of tooth profile error distortion,the influence of processing parameters on cutting force is studied.The ABAQUS dynamic module is used to simulate actual cutting,and the finite element simulation model is established,including the setting of tool and workpiece materials,the simplification and meshing of simulation model by Hypermesh,the setting of contact friction model,the selection of cutting separation and fracture criteria,and the calculation of ABAQUS after the parameter setting is completed.According to the three factors of cutting parameters affecting cutting force,simulation research is carried out.The law of cutting speed affecting cutting force,back feed affecting cutting force and feed affecting cutting force is obtained.The law of three factors affecting cutting force is analyzed,and the processing parameters of reducing cutting force are obtained to reduce the deformation of gear ring caused by cutting force.Finally,according to the influence of the cutter on the tooth profile accuracy when shaping,the finite element simulation is carried out for the two parameters that the rake angle and back angle of the cutter have a greater impact on the tooth profile accuracy.Relying on the cutting force as the reference object,the cutting force variation caused by the change of front and rear angles is simulated by finite element method.According to the change law of cutting force,the parameters of front and rear angles which reduce the cutting force are obtained,and the tooth profile accuracy error caused by the chatter of machine tools and workpieces caused by cutting force is reduced.