ZA Worm Drive Finite Element Analysis Based On ANSYS

As a typical drive mechanism,worm drive mechanism is widely used.In the traditional design of worm gear transmission,the formulas for the worm gear tooth contact fatigue strength,the tooth root bending strength and stiffness worm deformation and gear check are the approximate formula which are derived based on the formula for calculating gear,using Hertz contact theory in certain conditions,and assumpting that the load along the contact line is uniformly distributed.For the worm drive which instantaneous contact line is spacial curve, the Hertz contact theory,requiring the shape is the regular is difficult to study pair tooth contact intensity.Besides,the traditional method can not reflect gear tooth surface contact stress distribution.With the development of computer and growing perfect of elasticity finite element method,it provides an effective way for the study of the carrying capacity of worm drive.This paper,ZA worm drive for the object,uses finite element analysis software ANSYS to analyse ZA worm drive process.The main work was completed as follows:1,Settle the mathematical model of ZA worm,worm gear tooth surface,and based on the original mathematical model,a mathematical expression for both sides of the worm gear tooth surface is derived in accordance with modeling need,which is theoretical basisas for establishing the model of ZA worm drive.2,Study the method in which a worm drive model entity is created in a CAD software.Because the tooth surface of worm and worm gear is a complex space surface,the model created by using similar methods has the theoretical error,not suitable for finite element analysis.According to B-Spline of space surface modeling theory in computer-aided geometric design,the paper comes up with a method of establishing surface of the worm gear based on bi-cubic B-spline interpolation,and creates a entity model of ZA worm drive in SolidWorks,and analyses and caculates the model errors.Through the control of the number of rows and columns of interpolation matrix,the interpolation error can be confined to the scope needed.3,In the ANSYS,describe in detail the pre-treatment process of surface-surface contact,and according to the actual situation simplify the entity model.In ZA worm drive under the same load analyses contact state,contact stress,load distribution in different meshing locations in the cycle of the worm gear teeth rotation,obtain the ratio of load distribution between the meshing teeth in the meshing process.Analyse contact stress and deformation in the same meshing location under different load.Obtain the curve of worm gear contact stress as changes with the load,and the curve of the twist angle of the worm as changes with the input load.4,Against the three errors of the worm in the processing and installation process,analyse respectively the impact of every error on the contact state and contact stress in the process of ZA worm drive.