ABSTRACT
When a surface texture is formed on the bearing surface of a journal bearing, the lubrication characteristics change due to changes in the fluid film thickness. According to previous studies, when the entire bearing surface is textured, 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 by the experiments. In the study, to investigate the effect of the texture position of the bearing surface on the static and dynamic characteristics of a partially textured journal bearing, experiments were conducted with a test bearing of which 90° texture is attached to the loaded or unloaded sides of the bearing surface. The experiments confirm that the load-carrying capacity depends on the circumferential position of the texture. When the texture is placed on the unloaded side of the bearing surface, the load-carrying capacity is more significant than that of the bearing with the texture placed on the loaded 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.
