Hydro-Dynamic Lubrication Characteristics of Floating-Bush Bearing Used for Turbocharger. 1st Report, Approximate Analysis of Hydro-static Pressure and Oil Flow Due to High Pressurized Oil Supply.

Abstract

Hydro dynamic Lubrication analysis of floating bush bearing considering oil supply pressure is important for reducing friction loss or vibration of turbocharger. in this paper, hydro-static pressure and oil flow in the floating bush bearing due to high pressurized oil supply are investigated. From three dimensional flow calculation, it is found that static pressure is transferred not only to outer film but also to inner film through bush hole, and that the amount of static pressure in inner and outer film is force which push shaft and bush to opposite side of oil supply hole. In addition, it is clarified that influence of bush hole position on the static force and the oil flow is small enough to ignore. These calculation result has been verified by the experiment. Furthermore, based on the linearity of flow in the bearing and the independence between inner and outer film, it is shown that 2 D flow calculation of Reynold's equation considering pressure boundary condition of oil supply can approximate 3 D flow calculation results for simplicity.