Static And Dynamic Numerical Calculation And Dynamics Photoelasticity Experiment Study On Involute Spur Gear Pair

The standard involute cylinder gear is studied in this paper. The formula for the tooth shape curves of dedendum is deduced by means of the Theory of Conjugate Surfaces, and the two-dimension and three-dimension accurate models are established based on the formula. The effect to curvature and intensity of root caused by the variation of cutter tip curvature radius was analyzed. Static and dynamic FEM calculations were executed under four loading conditions and the error was analyzed for the simplified gear model.A new boundary condition is proposed in present work that the radial and axial displacement is constrained and the rotation is allowed. The inner torsion caused by the high speed rotation is applied on the initiative wheel, and the distortion load arose from the outer resistance is acted on the driven wheel. The three-dimension gear contact model is created and then is used for finite element analysis. The results indicate that the calculation according to the new boundary condition is more approach to the true value than the old one.The gear transmission is one of the most important mechanical transmissions. Well lubrication between of the gears is the key factor effecting the gear transmission. In order to analyze the influence of various parameters on film of gear lubrication, the multi-grid method is introduced by its application in the elastohydrodynamic lubrication (EHL) of involute spur gear. The results presented in this paper are satisfied and the multi-grid method has been proved as a powerful and robust algorithm for its good numerical stability and high convergence speed. The calculation and analysis indicate that the oil film thickness will be become thicker with the increase of gear modulus, transmission ratio, pressure angle, rotating velocity and oil viscosity. This would decrease the wearing and gluing of the gear.A full transient elastohydrodynamic lubrication solution of an involute spur gear was obtained by utilizing the multigrid method, which takes into account the variation of equivalent curvature, entertainment velocity and load with time along the line ofaction, without the lubricant thermal and rheological effects. The influences of load spectrum, where the load is carried by one pair of teeth and two pairs of teeth repeatedly, and impact load when the teeth come into action on the elastohydrodynamic lubrication are analyzed as well. The dynamic results are compared with static ones.The impact loadings with different pulse width are exerted on the model of polycarbonate gears in Photoelastic experiment. The dynamic photoelastic isochromatic fringe images at different moment were recorded by means of instantaneous image capturing system. The experimental results coincide well with the results calculated by FEM.