Patent ID: 7375448

Claim:
A motor comprising: a housing fixed to a lower fixed body and having an inner central portion to which a core with a coil wound around it is fixed; a fixed block having one end fixed to a center of the housing and also having other end on which a coupling groove is formed; a shaft disposed at a center of the coupling groove and having a lower end fixed to the fixed block; a sleeve rotatably coupled to the shaft to form a fluid dynamic bearing by forming an oil gap between the sleeve and the shaft, and also rotatably coupled to the coupling groove; a hub having a central portion coupled to the sleeve to rotate together with the sleeve and having a downwardly extending portion to an inner surface of which a magnet generating an electromagnetic force due to an interaction with the core is attached, a first air gap between the hub and an outer surface of the fixed block forming a first air dynamic bearing, a second air gap between the hub and a top surface of the fixed block forming a second air dynamic bearing, the first air dynamic bearing and the second air dynamic bearing generating an air dynamic pressure; circular first and second thrust plates respectively fixed to upper and lower portions of the shaft and forming fluid dynamic bearing surfaces between the first and second thrust plates and the sleeve; and an upper end cap fixed to an upper end portion of the sleeve and rotatably supported on an upper end of the shaft.