Parametric Modeling Of Spiral Bevel Gear Based On Machining Principle And Its Simulation Analysis Of Meshing Performance

Spiral bevel gears are widely used in transmission mechanisms in aerospace,transportation and other fields with the advantages of strong bearing capacity and meshing stably.Strength analysis of spiral bevel gear tooth plays an important role in ensuring the stable and safe operation of the transmission mechanism.When using the finite element method to simulate meshing performance and analyse tooth strength of spiral bevel gear pair,the accuracy of gear model used for simulation and the effectiveness of simulation of dynamic meshing process will affect the accuracy of simulation results.At present,the gear model created by spherical involute equation has a certain deviation from the shape of gear tooth obtained by actual machining.A few gear models created by modeling method based on machining principle mostly neglect the description of the shape of tooth root transition surface,resulting in the model is not complete.In addition,the static analysis commonly used in meshing simulation and the neglect of tooth surface contact strength and root bending strength analysis greatly affect the accuracy and completeness of simulation analysis.Aiming at the problems in existing research,this thesis firstly derived the complete and accurate equations of tooth surface tooth root transition surface and tooth root surface based on milling principle and knowlege of space coordinate transformation.A detailed derivation process and result were given for driving gear tooth surface with machining error correction and the driven gear tooth surface with opposite spiral direction.According to the accurate tooth surface equation of spiral bevel gear pair,the parametric modeling of solid model and finite element model of spiral bevel gear was realized,which effectively improved the model accuracy and efficiency of gear modeling.Meshing performance simulation analysis of precise gear pair model was implemented by using the transient simulation analysis function of ANSYS software.Tooth surface contact performance and root bending stress in simulation results were mainly discussed.The variation trend of tooth surface contact stress and root bending stress is in accordance with the basic meshing law of gear pair,which verifies the effectiveness and accuracy of parametric modeling method and tooth surface equation which accords with actual machining.In the study of tooth surface meshing performance,it was found that tooth surfaces of driving and driven gears are diagonal contact with each other slightly and the contact area is biased toward big end of gear tooth.Finally,in order to obtain a stable and ideal tooth surface contact zone and improve the contact performance of tooth surface,tooth surface modification of the spiral bevel gear pair is studied and tooth surface equation after modification was derived.Parametric modeling and meshing performance simulation analysis of spiral bevel gear pair with tooth surface modification were also carried out.After analyzing the simulation results,it was found that tooth surface contact zone of gear pair with tooth surface modification is substantially stable in the middle of the tooth width,which reflects the meshing advantages of modified gear pair.The values of tooth surface contact stress and root bending stress increase slightly,while the variation trends of these two kinds of stresses are less affected and still conform to basic meshing law.