HYDRODYNAMIC BEARING DEVICE

摘要

A hydrodynamic bearing device which supports a relative-rotation shaft or bearing by the hydrodynamic pressure of lubricating fluid which develops in a clearance between the bearing and the shaft, wherein leakage of the lubricating fluid to the outside of the bearing is satisfactorily prevented by a simple arrangement. A fluid pressing means applying to the lubricating fluid (5) an inward pressing force directed from the opening side of the bearing clearance toward the closed side, for example, a hydrodynamic pressure producing groove (13a) in which a hydrodynamic pressure (Pa1) having an inward vector component and a hydrodynamic pressure (Pa2) having an outward vector component are simultaneously produced, the hydrodynamic pressures being unbalanced in that the hydrodynamic pressure (Pa1) having an inward vector component is prevailing, has an inward pressing force imparting action which ensures that the lubricating fluid (5) in the bearing clearance is constantly pressed toward the closed side of the bearing clearance to hold that the gas-liquid interface (6) of the lubricating fluid (5) so that it is pushed inward. By setting the filling amount of the lubricating fluid (5) at a value with which the fluid pressing means is filled with the lubricating fluid (5) even upon occurrence of relative movement of the gas-liquid interface (6) toward the bearing clearance, which relative movement takes place upon relative upward movement of a thrust plate (16) or the like in the thrust direction, leakage of the lubricating fluid (5) through a seal portion (RS) is satisfactorily prevented.