Research On Meshing Characteristics Of Cycloid Gear Hypoid Gears With Heat Treatment Distortion

Extension epicycloids hypoid gear will exhibit tooth surface fatigue damage under high-speed and heavy-duty conditions.Usually,heat treatment will increase the hardness of the tooth surface and increase its wear resistance and fatigue resistance.Quenching with simple gears is usually done with heat treatment under a cooling medium with a uniform flow rate.The influence of thermal strain and tissue strain on its accuracy is mainly studied.For a hypocycloidal hypoid gear with a relatively complicated shape,The heat treatment also needs to consider the influence of the change of heat transfer coefficient on the tooth surface quality under the flow of the quenching cooling medium.The quality of the gear's dynamic mechanics will directly affect the comfort of the car.The bearing forces,impacts,and vibration and noise under high-speed and heavy-duty conditions are currently the main objectives of the study.Therefore,for the study of cycloidal gear hypoid gears,the whole process of carburizing quenching heat treatment and dynamic meshing was numerically simulated.The details are as follows:(1)The difficulty in the heat treatment simulation of cycloid gear hypoid gears is mainly in its microstructure evolution and thermal distortion.The heat treatment process was developed based on 20 CrMoH material properties.The use of professional material simulation software JmatPro to calculate the material phase transition and thermal physical properties;Selecting Heat Treatment Simulation Software Deform-HT to Simulate Heat Treatment of Gears;In order to make the simulation closer to the actual heat treatment effect,the dynamic boundary conditions of the heat transfer coefficients considering different flow rates of the quenching cooling medium were used for quenching,and the carbon element distribution,temperature of the gear tooth surface,tooth top,tooth root,bottom surface and tooth core were obtained.Field distribution,distribution of tissue fields and distribution of stress and strain fields;The hardness values of gear tooth surface hardness,tooth core hardness,internal hole ellipticity,and flatness of inside and outside surface after heat treatment all meet the actual heat treatment requirements of gears.(2)In order to ensure that the reconstructed tooth surface has small errors and high precision,the pre-processed cycloid hypoid gear point cloud data is pre-processed with the professional reverse processing software Imageware,and the gear tooth surface is reconstructed using the powerful inverse function of the software.The error analysis was performed on the tooth surface.It was found that the lateral deviation,negative deviation,geometric deviation and positive normal deviation of the gear's concave surface and convex surface were all less than 0.5% of the gear diameter.Finally,using UG to complete the reverse modeling of the gear model,and use Adams software to simulate the transmission error of the gear model in positive,reverse,neutral forward,and neutral reverse conditions,and the relative error of the transmission is within 0.13%.(3)Cycloid hypohedral gear model is complex,so the mesh is divided into meshes using professional meshing software Hypermesh and imported into dynamic simulation software Abaqus for contact mechanics research to obtain positive,reverse,neutral,and neutral receding.The law of contact force and contact area under working conditions.Through the analysis,it was found that the contact force between the large and small wheels is positive and small,the contact area has small fluctuations and obvious periodicity,and the gear transmission is stable.In the neutral operation,the contact force and the contact area between the large and small wheels are large and the fluctuation range is wide,the impact is significant,and the gear is greatly damaged.(4)By comparing the carburizing and quenching heat treatment and contact performance tests of the parabola hypoid hypoid gears,the numerical simulations of gear tooth surface hardness and tooth core hardness are similar to experimental measurements.The measured errors of the big-end,small-end,root,and tip of gear difference surface are the largest,and the numerical simulation is similar to the actual measurement result.The position of the digital contact impression and the actual gear contact impression is approximately the same,and the tilt rate is not much different,but there is a slight deviation in the shape of the contact area.