回転軸系の自励振動に関する研究(第3報)

ジャイロ効果の影響

抄録

In the present paper, some results of numerical analysis and experiments on the relation among internal damping force, gyroscopic effect and generation of self-excited vibration of rotating shaft system is described. The model used for analysis is a shaft horizontally supported on two ball bearings, with one rotor at the center of its span. The internal damping force and the gyroscopic moment are taken account in equation of motion of the system. Using asymptotic method, the equation for the first approximate solution is derived. Numerical calculation is carried out by Runge-Kutta-Gill's method. The main results obtained are as follows: (1) The characteristic amplitude and phase angle vary depending on the ratio i_p of the polar moment of inertia and the moment of inertia of the rotor. (2) With smaller i_p, maximum amplitude becomes smaller, and critical speed becomes lower, while the phase angle becomes larger. (3) When the system of rotating shaft has an internal damping force, the smaller the rotor's i_p is, speed ratio of stability limit becomes smaller, and the self-excited vibration is apt to occur.