Measurement of Dynamic Characteristics of Partially Textured Journal Bearings

Abstract

When a surface texture is formed on the bearing surface of a journal bearing, the load-carrying capacity of oil film decreases due to the increases in apparent film thickness. Besides, Yamada et al. demonstrated that the hydrodynamic force in the circumferential direction decreased, and the stability of the rotating shaft improved. Our numerical studies showed that maintaining the load-carrying capacity and improving the stability of a rotor supported in the bearing can be achieved at the same time if the texture is provided in an appropriate region, but the results have not been confirmed in the experiments. In the study, to investigate an effect of the circumferential position of the texture on the static and dynamic characteristics, experiments were conducted with a test bearing of which 80° texture is attached to the load or unload sides of the bearing surface. The experiments show that the texture is placed on the unload side of the bearing surface, the load-carrying capacity is more significant than that of the bearing with the texture placed on the load side. On the other hand, the reduction of the cross-coupled stiffness coefficient, which is the cause of the self-excited vibration, is slightly higher when the texure is placed on the loaded side.