1964 年 30 巻 218 号 p. 1238-1244
While oil whip phenomena can rationally be explained by Y. Hori's theory, it does not quantitatively give a good agreement for the stability of a rotor because of the assumption ; "the bearing is infinitely long". In the present paper, the oil film force on journal is derived under the short bearing approximation, and the stability chart of an elastic rotor supported by journal bearings is given by means of the Routh-Hurwitz's criterion from the equation of motion of the rotor under the action of oil film force. Experimental results by using journal bearings with L/D ratios ranging from 0.07 to 2 are comparea with calculated values from this chart. It is concluded that the chart is extensively applicable to most of practical rotating machinery with journal bearings.