EFFECTS OF BEARING DEFORMATION ON THE PERFORMANCE OF HYDRODYNAMIC BEARINGS

Abstract

The subject of elastohydrodynamic (ehd) lubrication, during its earlier development, conventionally included the ehd analysis of lubricated point and line contact such as in rolling element bearings, cams, and gears. However, during the last twenty years the area of 'ehd lubrication has been widened to encompass the analysis of distributed pressure 'contacts which occur where a lubricant film separates the sliding surfaces to support a load; a typical example being a slider bearing itself. Though the bearings are generally designed using the data developed with the assumption that their surfaces are rigid, the continual growth of machines, requiring their bearings to operate at high speeds and carry heavy loads, requires analysis and design of bearings taking their elastic deformation into account. The bearing deformation may quite often be of magnitudes of the order of the film thickness, thus affecting the clearance space geometry to an extent that the actual performance characteristics may become significantly different from those computed with rigid bearing assumption. The work reported in this thesis was planned in view of these forethoughts. This thesis is concerned with the analysis of some Slider and journal bearing configurations taking deformability of the bearing liner into account. The literature on the ehd studies of the self acting bearings is scant. The studies iv usually available in this area are devoted to isoviscous lubricant and laminar operating conditions. The solutions have been obtained by assuming simplified structural model for bearing deformation and by considering half or full Sommerfeld boundary for the trailing edge of the fluid film for the journal bearings. Also, the available studies are mostly limited to the determination of the static performance characteristics. With a comprehensive survey of the available literature, it was felt that a generalised analysis on ehd lubrication of hydrodynamic bearings be made unhamp,red by the restrictive assumptions hitherto commonly used...