Rotor Axial Vibration Caused by Gear Coupling

Abstract

This paper deals with an axial vibration of a horizontal rotor which is driven through a single craw type gear coupling under no load operating conditions. The effects of coupling misalignment on the vibration are experimentally investigated. Under good alignment conditions, remarkable axial vibrations with large amplitude and long period (in some cases 3mm in amplitude and 3sec. in period) were observed in certain narrow speed ranges. The period, which almost coincides with that of beat of the torsional vibration of a rotor, becomes larger with an increase in amplitude. When a large angular misalignment exists, the rotor axial vibration is not likely to occur. In order to illustrate the mechanisms of the axial vibration, three models are proposed on the basis of experimental results.