Lubrication Characteristic Analysis And Simulation Of Camber Indexing Cam Mechanism

The globoidal indexing cam mechanism is prone to wear and pitting corrosion in the transmission application,and improving the lubrication performance of the mechanism is the key to solve the problem.In this paper,the globoidal indexing cam mechanism is taken as the research object.Starting from the elastic lubricating oil film formed in the process of indexing period transmission,the basic parameters of mechanism lubrication and the thickness of elastic lubricating oil film formed in the meshing process of mechanism indexing period are studied,and the influence of different factors on the thickness of elastic lubricating oil film is analyzed.The main contents of this paper are as follows:(1)The structure and working principle of globoidal indexing cam mechanism are analyzed in detail.Based on the conjugate principle of spatial envelope,the method of rotation variable and differential geometry,the working profile curve of cylindrical roller globoidal indexing cam mechanism is analyzed.The equations and conjugate equations of working surface profile are derived and solved.The geometric parameters and motion parameters are set to solve the working surface coordinates.The basic parameters of the mechanism lubrication performance are studied,and the induced principal curvature,pressure angle and entrainment speed of the working surface dividing period are derived,and the correctness of the established mathematical model is verified.The three-dimensional solid model of globoidal indexing cam mechanism is established,and the assembly of mechanism is completed.(2)Aiming at the study of oil film pressure(contact stress)on the working surface of globoidal indexing cam mechanism during indexing period,a numerical analysis algorithm scheme is proposed,and the solution is calculated by combining the elastic line contact Hertz theory.In view of the correctness of the numerical analysis algorithm,the statics simulation analysis and verification of the mechanism indexing period meshing process are carried out.The same parameters are set,and the results are compared with the simulation results to verify the feasibility of the numerical analysis algorithm.(3)The theory and motion equation of Linear Contact Elastohydrodynamic Lubrication are systematically analyzed.Combined with the empirical formula of Hamrock Dowson,the relationship between the minimum oil film thickness of elastic lubrication and contact stress in indexing period of globoidal indexing cam mechanism is studied under steady condition.This paper defines different globoidal cam speed,studies the influence relationship and change law among contact stress,minimum oil film thickness and film thickness ratio,and analyzes the position where wear failure occurs most easily in indexing period meshing process of globoidal indexing cam mechanism.(4)Starting from the model of cylindrical roller globoidal indexing cam mechanism established in this paper,the shape of follower roller is changed and the parameters remain unchanged.The cone angle is added to the generatrix of cylindrical roller to form a cone.The surface equation and curvature change of tapered roller are deduced and analyzed.The same working conditions and parameters as cylindrical roller globoidal indexing cam mechanism are selected to simulate the change curve of contact length,contact stress and film formation in the meshing process of tapered roller mechanism.The comparison and analysis are carried out with cylindrical roller globoidal indexing cam mechanism,and the lubrication of globoidal indexing cam mechanism with different roller shapes is studied Performance impact.Creatively solve the contact stress in the meshing process of globoidal indexing cam mechanism in indexing period,and analyze the lubrication characteristics in the meshing process,which provides a theoretical basis for improving the transmission performance and lubrication performance of the mechanism,which has high practical value.