Patent ID: 7218023

Claim:
A spindle motor comprising: a rotating unitary shaft supported for rotation by a radial fluid dynamic bearing and a thrust fluid dynamic bearing; rotating means secured to said rotating unitary shaft; and a motor generating an electromagnetic force for rotating said rotating means, wherein said unitary shaft comprises a conical portion at one end of said shaft, said conical portion having an outer diameter expanding gradually toward said thrust fluid dynamic bearing and a straight portion having a fixed outer diameter; wherein said thrust fluid dynamic bearing is formed immediately at a bottom of said conical portion; wherein fluid is supplied between each of said fluid dynamic bearings and an entire surface of said rotating unitary shaft including an entire surface of said bottom of said conical portion, and wherein said radial fluid dynamic bearing comprises a conical bearing surface and a straight bearing surface, said conical bearing surface corresponding to said conical portion of the rotating unitary shaft, and said straight bearing surface corresponding to said straight portion of the rotating unitary shaft.