2011 年 77 巻 783 号 p. 4100-4110
This paper studies the oil whip stability characteristics of a Jeffcott rotor supported in tilting-pad journal bearings theoretically. The effects of design parameters such as type of bearing seat, pad inertia, length to diameter ratio (L/D), pad number, load direction and stiffness of the shaft on the stability characteristics of the rotor-bearing system over the wide operating conditions are shown. Types of bearing seat make a great effect on the stability characteristics of the rotor-bearing system. In the case of pivotable bearing seat, the stability threshold shaft speeds increase with the preload factor under wide operating conditions. On the other hand, in the case of non-pivotable bearing seat, the stability characteristics do not change much with the increase in the preload factor. Increase in L/D ratio decreases the stability threshold shaft speed when Bearing Modulus λ is low. Pad inertia destabilizes the rotor at the high shaft speeds only when bearing modulus is low. Pad number and load direction make little effect on the stability.