抄録
The effect of the spring and damping characteristics of a floating bush bearing on the stability is investigated numerically. The characteristics of the bearing's inner and outer oil film are calculated separately. In this calculation, the configuration of the bearing's surfaces, namely, the oil paths, and the increase of the temperature due to the bearing loss are taken into account. The rotor dynamics are then calculated and the characteristics of the unstable vibration of the rotor investigated. This kind of shaft-bearing system has four rigid vibration modes : two in which the bushes move in phase with the shaft and two in which the bushes move out of phase with the shaft. The spring constant of the outer oil film mostly affects the former two modes, whereas the damping characteristics of the outer oil film affects all modes. By taking the advantage of these effects, we can control the unstable vibration and eliminate the mode we need to avoid.
