Research On Cold Extrusion Forming Mechanism And Technology Of Large Lead Internal Thread

The fast-forward screw nut pair is an important functional part in modern electromechanical products and intelligent and automated production lines.It has the characteristics of large market demand and many specifications.As the core component of the fast-forward screw nut pair,the large-lead nut has the characteristics of high hardness,high precision and high manufacturing difficulty.Its processing has become the bottleneck of the fast-forward screw nut pair.This paper proposes a cold extrusion technology for large lead internal thread,which has good engineering and practical value for the realization of the manufacture of large lead nut internal thread in the fast-forward screw nut pair.The main research contents of this article are as follows:(1)Combining the theory of metal plastic deformation and the analysis of the characteristics of internal thread forming,the article studies the process of forming the thread teeth of the nut under the pressure of the tap extrusion.At the same time,the ridge load of the extrusion tap during the internal thread forming process is analyzed for further analysis The reason why the ridge behind the squeeze cone wears out faster.(2)This paper analyzes the design criteria of large-lead extrusion taps and the causes of the pitch error of large-lead extrusion taps.At the same time,the calculation formulas for the pitch error of single-end and double-end extrusion taps and the pitch error on the tap ridge are deduced.Distribution law.Finally,a method for compensating pitch error is proposed.Taking double-end extrusion taps as an example,an equal-pitch double-end extrusion tap model is established to lay the foundation for finite element numerical simulation.(3)In this paper,the DEFORM-3D finite element analysis software is used to study the cold extrusion process of large-lead internal threads with double-headed internal threads cold extrusion as the research object.This paper analyzes the changes of equivalent stress,equivalent strain,extrusion temperature and extrusion torque in the process of internal thread forming,and at the same time studies the metal flow behavior characteristics during the process of double-end internal thread forming.The research provides the basis.Finally,thechanges of the tapping torque of the tap during the forming process of single-end and double-end internal threads are compared and analyzed.(4)The article studies the process parameters of double-end internal thread forming and the structural parameters of extruded taps on the forming process,and optimizes the forming influencing factors by orthogonal experiment method,and obtains a set of process parameter values with small torque and The parameters of the tap structure and the optimization results were verified.