Dynamic characteristics analysis of a lead screw by considering the variation in thread parameters

Abstract

A lead screw is a mechanical transmission device which transforms rotary motion into translational movement. The main elements are screw and nut which establishes connection among them by the means of threads on respective element. It plays a major role in transferring the load between screw and nut during the travel stroke. This paper investigates the behavior of the lead screw, inside the withdrawal part of the circuit breaker of switchgear, by analyzing the mechanical response of the lead screw system. The various thread parameters such as thread pitch, nominal diameter etc. play an important role in force transmission as well as in overall efficiency of the mechanical system. This study is done by creating models of various thread profile such a square thread, acme thread, trapezoidal thread and simulating the results in the finite element analysis software ANSYS Workbench. This paper focuses on the effect of the thread pitch, nominal diameter, helix angle, screw length on the stress state and deformation within the screw. Also, the influence of screw pitch, screw length and screw nominal diameter on the withdrawal part of the circuit breaker’s natural frequency along its whole stroke is carried out using modal analysis.