Hydrodynamic bearing device, motor, recording disc driving apparatus and assembly jig

摘要

A hydrodynamic bearing device 4 comprises a shaft 41, a second thrust flange 41c, a sleeve 42, a radial bearing 71, and a thrust bearing 73. The second thrust flange 41c is fixed near one end of the shaft 41. A third cylindrical protrusion 42e that protrudes farther in the axial direction than the second thrust flange is fixed to or integrally machined at one end of the sleeve 42. A notch 50 that communicates between a radial inner space and a radial outer space separated by the third cylindrical protrusion 42e is provided to the third cylindrical protrusion 42e.