Reducing instabilities of mesh stiffness variation in two-stage gear using phasing method

Abstract

Mesh stiffness variation is a phenomenon that occurs in a mechanical system when there is a change in number of teeth within the system. This phenomenon leads to parametric instabilities and can cause gear systems to experience severe vibration. This paper investigates the effect of mesh stiffness parameters like mesh phasing and contact ratios, in reducing vibrations, when applied to two-stage gear train. Each gear pair is replaced by two gear pairs, each having half the width as that of primary gear pair. The present study has adopted a systematic approach to develop theoretical expressions for evaluation of instability regions that are created by the connections formed between stiffness variations present at the two meshes and four meshes of the primary gear pairs and replaced gear pairs, respectively. The paper has also studied primary instability, secondary instability and combined instability. Required mesh phasing to eliminate instability regions for four gear meshes was found numerically using MATLAB. It is observed that replaced four gear pairs with proper mesh phasing eliminate the instability regions of original two gear pairs of two stage gear train.