Research On The Tooth Modification Of Involute Straight Bevel Gear

The focus of this thesis is on the method of profile modification for involute straight bevel gear.By the method of analyzing characteristic of bevel gear, including the combined stiffness,transmission error,contact stress and the deformation of contact zone,to bring forward ideal profile modification curves to decrease the noise and vibration of bevel gear.It is difficult to built the model of bevel gear due to the complicated profile.At present,straight bevel gear is built with sphere involute,which is more accurate than the back cone involute.According to this case,this paper introduced a method that how to design the application of involute bevel gear with UG/OPEN API,and detailedly explained the proeess that develop a module of involute bevel gear with UG/OPEN API.It improves the precision of the model and is easy to modify,so it improves the efficiency of the modeling of the bevel gear largely.Static analysis and dynamic analysis of straight bevel gears in mesh are taken. The solid modle are divided into some parts through UG in order to conquer the problem,which the tntire solid model came down from CAD software can not be meshed using hexahedron elements.The boundary conditions and the constrain method of gear in mesh are given.Basic law is studied through the simulation of gears in mesh and some conclusions are drawn,which lay the foundations for the gear modifications.With the parametric model of the straight bevel gear,a series model of profile modified gear was developed.The non-linear infinite element model was obtained in ANSYS,An analysis was carried out on the result simulation of the gear.The simulate data demonstrated the effect of profile modified on blending strength, contact stress and bending stress.The result of research provided theoretical foundation for bevel gear modification.The necessary of profile and crown-gear modification has been shown through the phenomenon of the collision happed in the first and end time during the process of the mesh and teeth "end contact".Tooth profile modification with circular curve was developed for involute bevel gear,and the method of how to determine the maximal profile modification quantum,the center of the circular curve and correlated parameter was given.An analysis was carried out on the result of non-linear contact FEA and simulation of the gear.The simulate data demonstrated that the method of profile modification was reasonable and the amplitude of the transmission error fluctuation and the maximal contact stress of the profile modification gear was reduced efficiently.This paper also discussed the method of the crown-gear modification.The process of how to implement crown-gear modification with cure was introduced.The data of the contact zone deformation was obtained by the means of FEA,and this data was fitted to a curve.Crown-gear modification with antisymmetric curve has good result.