Research On Contact Characteristics Of Gear Systems Considering Meshing Misalignments And Modification Design

Gearing systems are widely used in various mechanical equipment and are subject to vibration and noise due to elastic deformation of the gear teeth,installation errors and manufacturing errors,which seriously affect the stability and service life of gear systems.Therefore,the study of gear system parameters and gear structure parameters on the gear system contact characteristics of the law is essential.In this paper,we take cylindrical gears as the research object,and establish the influence of considering the mesh line extension caused by gear elastic deformation,installation error and manufacturing error on the mesh stiffness of gears;considering the influence of shaft and bearing flexibility as well as the form of gear installation on the contact characteristics of the gear system for the whole system of gear transmission;proposing the corresponding repair methods for the phenomenon of mesh extension of gears and misalignment of gear system The corresponding reshaping methods are proposed for gear pair meshing extension and for the phenomenon of gear system misalignment.The research in this paper has.(1)Based on the energy method,this paper establishes an analytical model considering the gear mesh line extension and compares the results with the 3D contact finite element simulation method to prove the accuracy of the model.Compared with the traditional analytical model,it is proposed that the actual overlap of the gear teeth increases when they are deformed by load,resulting in the stiffness curve changing from a theoretical rectangular wave to a trapezoidal wave.It was found that the meshing stiffness of gears is non-linearly related to the load;changes in gear mechanism parameters cause changes in the base stiffness of the gear.;when the overlap of spur gear pair is close to 2,the phenomenon of three-tooth meshing will occur due to the mesh extension.(2)The Timoshenko beam theory based shaft system deformation calculation method is coupled with tooth surface contact analysis to consider the effect of full flexibility of the gear system on the misalignment of the gear pair,and an analytical model is established to consider the effect of the entire gear-shaft-bearing transmission system on the gear mesh stiffness and tooth surface contact.The effects of the gear mounting,power transfer path and load torque on the gear system are analysed and compared with the finite element method.The study shows that: the support layout form has a greater influence on the tooth contact characteristics,and the deformation of the shaft system will cause the tooth surface to be deflected;by studying the influence of the working conditions on the tooth contact,it is found that the power path has less influence on the gear system,and the deflected load becomes more serious as the load torque increases.(3)Based on the tooth surface deformation coordination equation,the gear reshaping parameters are introduced into the equation in the form of initial clearance,and the effect of different reshaping methods on the contact characteristics of the gear pair was studied.It can be found that gear reshaping has a significant effect on reducing gear vibration,gear reshaping will improve the uneven distribution of tooth surface load;tooth profile reshaping will smooth the transmission error of the spur gear pair and change the form of the original transmission error curve and tooth surface load distribution;tooth direction reshaping will change the tooth surface load distribution,but will not change the form of the stiffness curve.