Parametric Design And Contact Performance Research Of Automotive Transaxle Differential Gear Based On Tooth Modification

Straight bevel gear is mainly used for circular rotation movement between low speed intersecting shafts.It is an important power transmission component in automobile drive axle differential,and its contact performance has a very important impact on the whole mechanism system.Compared with other means of gear transmission,straight bevel gear has a compact structure,precise instantaneous transmission ratio,the advantages of high transmission efficiency and easy to manufacture,the chemical industry,energy,mechanical engineering and other fields has been widely used.Gear tooth profile modification parameters directly affect the straight tooth bevel gear contact performance,due to the complexity of bevel gear tooth profile for modeling for to a lot of difficulties,and mostly in terms of design modelling using cone to modeling of involute,cause the model precision is not in conformity with the standards.With the development of CAD modeling technology,the use of spherical involute instead of conical involute in modeling becomes more and more important for improving model accuracy,optimizing gear modification parameters and improving gear meshing performance.Based on the meshing theory of bevel gear geometry,combined with the secondary development of NX model,tooth modification technology and the stress analysis of the contact area of ANSYS finite element,the parametric design and the gear pair contact performance of the differential gear are studied in this thesis.The main research contents of this thesis are as follows:1.Research is carried out around the tooth modification technology of straight cone gear(including tooth profile modification and tooth direction modification)and the selection of related parameters.In the process of meshing transmission of bevel gear,the impact of snapping in,snapping out,and the phenomenon of snapping end to end indicate the importance of tooth surface trimming.2.Formation principle of spherical involute and derivation of related expressions.The GPA technique was used to obtain the fitting point method,and the errors of spherical involute and conical involute were compared.The formula of spherical involute is derived based on the instantaneous angular velocity of intersecting shaft and the characteristics of pitch cone,which is the theoretical basis for parametric modeling of spherical involute straight bevel gears.3.Parameterized modeling of straight bevel gear.Based on the secondary development software NX as the development environment platform,the author deeply understands,grasps and skillfully uses the secondary development technology of NX software.According to the requirements of the straight bevel gear drawing,the author uses the development tool set,combines the GRIP programming language and the modeling principle of the spherical involute tooth profile,establishes the spherical bevel gear tooth profile surface and the tooth blank profile surface,and achieves the parametric accurate modeling of the straight bevel gear.Using UG/OPEN other development modules,the input parameters of the modified bevel gear dialog box are quickly modeled and assembled.4.Finite element contact stress analysis of straight bevel gear.The static contact analysis of the modified straight bevel gear is simulated by ANSYS finite element analysis software.Firstly,the straight bevel gear was divided into several parts in NX software,and after the secondary development and virtual assembly of the gear,the tooth contact analysis of the meshing bevel gear was carried out by the finite element analysis software,and the traditional theoretical calculation was compared with the ANSYS analysis results,so as to verify the correctness of the ANSYS analysis.Then the simulation of the modified gear was carried out to compare the contact stress variation law of the tooth surface of the straight bevel gear before and after the modification.5.Inspection Certificate of straight bevel gear roll.The gear was machined according to the model parameters of bevel gear,and the contact condition of the meshing contact area of bevel gear was checked by rolling machine,and the correctness of the shape modification was verified.In this thesis,NX modeling software and ANSYS stress analysis software are used comprehensively.Through the above work,the whole analysis process of bevel gear parametric modeling,rapid modification,automatic assembly and contact analysis of the modified bevel gear is completed,which greatly improves the efficiency of gear modification research and finite element simulation analysis,reduces repetitive labor,and improves the accuracy of model establishment.It lays a theoretical foundation for realizing three-dimensional parametric modeling of bevel gears,rapid modification,assembly and contact analysis of straight bevel gears,etc.