Meshing Characteristics Analysis And Application Research On Involute Worm And Helical Gear Drive

With the improvement of the electronic control and digitalization of automotive products,the technology of automotive wire control has the widespread application,such as Braking-by-wire,Steering-by-wire,Suspension control-by-wire,etc.As the core and key part of the application of automobile drive-by-wire technology,mechanical actuator is required higher reliability,lower noise,smaller size and lower cost.Due to large transmission ratio,compact structure,stable transmission and low manufacturing costs,the involute worm and helical gear drive is widely used in automotive wire-controlled mechanical actuator.It also has the broad application prospects and the value of use.Combined with the project of "Development and industrialization of car seat horizontal drive mechanism",this thesis takes the involute worm and helical gear drive used in the horizontal drive mechanism in the automobile drive-by-wire adjustment actuator as the research object.By using the combination method of theoretical analysis,numerical calculation,finite element simulation and test verification,it explores the rules evolution of the meshing characteristics on the involute worm and helical gear drive under the coupling of multiple physical quantities such as design parameters,assembly errors and tooth profile modification.It provides a theoretical basis for key engineering issues such as vibration and noise reduction,life extension and reliability improvement of the drive,the main research contents are as follows:(1)Based on the principle of meshing and gear manufacturing,an analysis method in the meshing theory of the involute worm and helical gear drive with the counterpart rack is proposed,the meshing equation and contact ratio of the involute worm and helical gear drive are derived by this method.According to this calculation method,the principal curvature and direction of the instantaneous meshing point are established and the mathematical model of contact ellipse and contact trajectory on the tooth surface are presented.(2)According to the meshing principle of the involute worm and helical gear drive,the influence of design parameters for the drive on the contact area,contact trace distribution,contact stress and contact ratio of the drive are researched.Furthermore,based on Visual Basic programming language,the design and analysis software of small modulus involute worm and helical gear drive is compiled,which achieves the fast parameterized design and analysis of the drive.(3)With the theoretical contact analysis model of the tooth surface and the finite element simulation analysis software,the variation rules of the contact area and contact trajectory of the drive are studied under different assembly errors.With the assembly errors under the rated load,the influence of tooth surface contact stress and contact trace are analyzed;in order to reduce the effect of tooth surface stress concentration and meshing impact which are caused by the different errors,the gear modification research of the drive is carried out,and the tooth surface contact analysis is performed on the drive after the tooth profile modification,which reveals the influence of different tooth profile modification methods and parameters on the meshing performance of the drive.At last,the modification method is given,which can improve the dynamic contact performance of the drive.(4)The prototype production,performance test and application research of the drive are carried out,the test bench for the involute worm and helical gear drive is built to test meshing performance.The contact and vibration characteristics of the drive are tested and analyzed,the correctness of the theoretical analysis method and optimization design for the meshing characteristics of the involute worm and helical gear drive are verified,the application of the involute worm and helical gear drive in related product is achieved.