Combination Tones in a Rotating Shaft System

Abstract

The restoring force of an elastic shaft supported by ball bearings has nonlinear spring characteristics. In such a rotating shaft system, various kinds of forces due to the unbalance of a rotor, irregularity of balls, and so on, work and consequently combination tones occur. In this paper, we shall discuss the characteristics of all kinds of combination tones experimentally and theoretically. Especially, with attention to nonlinear components represented by polar coordinates, the possibility of occurrence and the shapes of resonance curves are investigated.