Analysis Of The Method Of Champing Thin-walled Parts And The Internal Cone Expansion Chucking

When thin-walled parts are machined on the lathe,clamping thin-walled parts is a difficult problem.In order to reduce clamping deformation,this paper studies the method of champing thin-walled parts;Finite element method is used to calculate the clamping force and the clamping deformation of thin-walled parts which is clamped by the internal cone expansion chucking with different structural parameters;The orthogonal table is used to arrange modeling calculation parameters,the mathematical model of the internal cone expansion chucking is established by stepwise regression analysis.In this paper,the positioning principle is analyzed,there are four kinds of chuckings: chuck,spring jacket and spring mandrel chucking,hydraulic expansion fixture,conical elastic chucking,the working principles and applications of chuckings are analyzed,the design of the internal cone expansion chucking,automatic fixture through internal expansion positioning and end face clamping for internal gear part are described.Finite element method is used to simulate the two kinds of internal cone expansion chucking:model I(clamping petals contact bulging shaft by long conical surface)and the model II(clamping petals contact bulging shaft by short conical surface),the results of calculation are compared,the results show that the clamping force from the model II is greater than the model I,so structure of model II is more reasonable than model I.The orthogonal table is used to arrange six calculation factors:the inner diameter,the wall thickness,and the length of thin-walled parts;the half cone angle and the thickness of thin-walled part of conical elastic jacket;and the pulling force of rotary hydraulic cylinder,the clamping force and the clamping deformation based on model II are obtained through finite element method.The influence order of six factors for the clamping force and the clamping deformation is obtained by range analysis;The mathematical model of the clamping force and the clamping deformation are obtained;the relation curve and surface between each factor and the clamping force or the clamping deformation are obtained,which provides reference for determining the values of the structural parameters of the chucking,also provides basis of the clamping force prediction and the clamping deformation prediction of thin-walled parts.