Patent ID: 8888369

Claim:
A rotating device comprising: a rotating body having a hub on which a recording disk is to be mounted and a shaft joined to a center hole of the hub; a fixed body having a base and a surrounding member that is fixed to the base and surrounds the shaft; and lubricant interposed between the rotating body and the fixed body, wherein the surrounding member has both a tubular sleeve for housing the shaft and a tubular housing for surrounding and fixing the sleeve, wherein a first radial dynamic pressure generating groove and a second radial dynamic pressure generating groove, which are used for generating radial dynamic pressure, are formed on at least one of an inner circumferential surface of the sleeve and an outer circumferential surface of the shaft, the second radial dynamic pressure generating groove being provided at a position spaced apart from the first radial dynamic pressure generating groove toward the base, wherein the sleeve has a flange portion protruding radially outward at an end portion of the sleeve near to the hub, and a sleeve concave portion, which is made by axially concaving at least part of an area corresponding to a wall thickness of the sleeve on an inner circumference side of the flange portion, is circumferentially provided, wherein a circumferential hub concave portion for housing at least part of the flange portion is circumferentially provided on a surface of the hub near to the sleeve, and a gap between the circumferential hub concave portion provided on the surface of the hub near to the sleeve and the at least part of the flange portion which is housed in the circumferential hub concave portion is filled with the lubricant, and wherein the hub has an enlarged-thickness portion that enters the sleeve concave portion and whose outer diameter is substantially equal to a diameter of a side surface of the sleeve.