DYNAMIC PRESSURE BEARING WITH IMPROVED STARTING CHARACTERISTICS

摘要

A dynamic pressure bearing with improved starting characteristics, wherein the depths of grooves (2, 5) provided in either of the opposite surfaces of a radial bearing part or a thrust bearing part are made shallower gradually along a fluid flow from the upstream to the downstream side so as to provide a uniform pressure distribution in the grooves so that a dynamic pressure in the grooves is distributed, bearing supporting force is increased, and dew condensation is minimized, a slope is provided, from the inner peripheral part to the outer peripheral part of the bearing part, on either or both of the surfaces of the thrust bearing part opposed to each other in outer radial direction and an axial clearance is increased to approx. 2 mu m on the outer peripheral part so that a contact portion between both members at the time of stoppage of the bearing is brought near the axis to reduce a resistance at the time of starting in order to reduce a power torque, a contact at the thrust bearing part by the oscillation from the outside is avoided, and a second thrust plate (11) is fixed to the end of a sleeve (3) on the opposite side to the side opposed to a thrust plate (4) and, at the time of stoppage of the bearing, a load on the rotation side is supported by the second thrust plate (11) and the end face of the shaft (1) opposed to the second thrust plate so as to reduce a resistance at the time of starting.