Thrust dynamic pressure bearing, spindle motor using thereof, and information recording/reproducing device using the spindle motor

摘要

A thrust dynamic pressure bearing with high inclination-resistant rigidity against axis runout and additionally low bearing loss torque is implemented. Herringbone grooves ( 131 ) having intermediate bends ( 132 ) are provided on rotating-side bearing surface ( 11 ) provided on the rotating-side bearing member. When rotating-side bearing surface ( 11 ) rotates in direction A (clockwise), lubricating oil generates dynamic pressure in an area centering on intermediate bend ( 132 ) along radially outer part ( 133 ) and radially inner part ( 134 ) of herringbone groove ( 131 ). As a result that groove width (G) of a dynamic pressure generating groove and width (L) of a land adjacent to the dynamic pressure generating groove holds G>L at an arbitrary radius ( 2 ) position, a thrust dynamic pressure bearing with high inclination-resistant rigidity and additionally low bearing loss torque is provided.