| Non circular gear is mainly used to realize the transmission of variable ratio between two mechanisms.Compared with the cam and connecting rod transmission mechanism,the transmission is stable and high precision,so it has unique advantages compared with these traditional transmission mechanisms.Helical non-circular gear combines the advantages of straight non-circular gear and helical cylindrical gear,which has the advantages of stable transmission and strong load-bearing capacity.However,due to its complex design,manufacturing difficulties and other factors,it restricts its development in life.In recent years,with the continuous development of non-circular gear in the direction of transmission,the evaluation of dynamic characteristics and load-bearing capacity of gear teeth has become one of the main problems in its development and application.In view of this,the dynamic characteristics and load-carrying capacity of helical non-circular gear are studied in this paper.(1)Based on the gear meshing principle,the basic principle of helical non-circular gear and the closed condition of pitch curve are introduced.The calculation formula of the tooth profile curvature radius,the length of contact line and the equation of tooth crest and tooth root curve of helical non-circular gear are derived.According to the meshing principle of helical gear pair and the theory of generating method,the tooth space meshing coordinate system is established,and the tooth surface of helical non-circular gear is derived Parameter equation.(2)Based on ADAMS virtual simulation analysis software,the dynamic model of helical non-circular gear pair is established,and the change rules of mass center displacement and dynamic meshing force of helical non-circular gear under different helix angles are explored respectively.Considering the influence of manufacturing and installation errors on the dynamic characteristics of helical non-circular gear teeth,the relationship between center distance error and actual center distance,transmission ratio,pressure angle and tooth diameter is studied The relationship between curvature radius and dynamic meshing force is analyzed,and the dynamic meshing force of helical non-circular gear under different working conditions(load,speed,friction coefficient)is studied.(3)Put forward a kind of generalized helical non-circular gear bearing capacity calculation method,and has carried on the stress analysis of gear,explores the basic parameters of radial force,circumference force,and the influence law of axial force,and deduces the calculation of non-circular gear instantaneous equivalent bevel gear method and calculation formula of stress correction coefficient and tooth shape coefficient,the helical non-circular gear tooth surface contact stress and tooth root bending stress change rule,probes into the basic law of the influence of structural parameters on the carrying capacity of gear on.(4)Based on Workbench,the virtual finite element simulation model of helical non-circular gear was established,The solid model of helical non-circular gear pair is processed based on five axis CNC machine tool,and the experimental platform of helical non-circular gear is built.Finally,the finite element simulation data,experimental data and theoretical calculation data are compared to verify the correctness of the evaluation formula of helical non-circular gear bearing capacity.The vibration fluctuation of helical non-circular gear reducer under constant speed and different load torque as well as constant torque and different speed is studied,which provides experimental basis for vibration reduction and noise reduction of helical non-circular gear reducer in the subsequent optimization design process.Through the study of the above content,it provides a theoretical basis for the study of the dynamic characteristics of helical non-circular gear and the evaluation of the bearing capacity of gear teeth,and provides a reference for the subsequent optimization design and industrial application of gear teeth. |
PDF Full Text Request