Yukio Hori

A Three-Dimensional Analysis of Thermohydrodynamic Performance of Sector-Shaped, Tilting-Pad Thrust Bearings

The thermohydrodynamic performance of the bearing is analyzed, taking into account the three-dimensional variation of lubricant viscosity and density. The effect of pivot position and operating and environmental conditions on the performance is studied. The present analysis is compared with the isoviscous or the two-dimensional analysis, and is found to predict the bearing performance more accurately.

Earthquake-Induced Instability of a Rotor Supported by Oil Film Bearings

The effect of seismic waves on the stability of a Jeffcott rotor supported by oil film bearings is investigated by calculating loci of the centers of the journal and the disk using the Runge-Kutta-Gill method. It will be shown that a linearly stable rotor can become unstable under a strong artificial shock and a real seismic wave, if it is running at speeds above twice the first critical speed, which is close to the natural frequency of the rotor

Theoretical Condition for the Cxy=Cyx Relation in Fluid Film Journal Bearings

A computer program for calculating dynamic coefficients of journal bearings is necessary in designing fluid film journal bearings and an accuracy of the program is sometimes checked by the relation that the cross terms of linear damping coefficients of journal bearings are equal to each other, namely “Cxy = Cyx ”. However, the condition for this relation has not been clear. This paper shows that the relation “Cxy = Cyx ” holds in any type of finite width journal bearing when these are calculated under the following condition: (I) The governing Reynolds equation is linear in pressure or regarded as linear in numerical calculations; (II) Film thickness is given by h = c (1 + κcosθ); and (III) Boundary condition is homogeneous such as p=0 or dp/dn=0, where n denotes a normal to the boundary.

Seismic Response of a Linearly Stable, Misaligned Multirotor System

Nonlinear behavior of a multirotor system supported by oil film bearings is investigated theoretically by calculating loci of centers of disks and journals of the system using a time marching method. The oil film force of bearings is obtained by solving the Reynolds equation at each time step by a rapid solution presented previously by the authors. It will be shown that a two-disk/four-bearing rotating system operated under the linear stability limit but above twice the first critical becomes unstable when sufficiently large external shocks, an artificial sinusoidal shock and real seismic waves are given to the system. The effect of misalignment of bearings is also examined closely in this study. Presented at the 47th Annual Meeting in Philadelphia, Pennsylvania May 4–7, 1992

A study on the static characteristcs of swing pad journal bearings applied to horizontal rotor.

Chiu studied the static characteristics of swing pad journal bearings for horizontal rotor. however, he used the experimentally obtained spring-constant values of the rubber support in his analysis. Therefore, the result can be applied only to the particular bearing he studied. For a more general treatment, in this paper, the spring constant was calculated by means of the finite element method and the influences of five geometrical parameters on the bearing characteristics were calculated.