Patent ID: 7612476

Claim:
A motor comprising: a stator; and a rotor including a hub portion and being rotatably supported through a dynamic pressure bearing with respect to the stator, the dynamic pressure bearing including: a shaft portion; a sleeve portion including an insertion hole into which the shaft portion is inserted, the insertion hole having an open end and a sealed end; and a lubrication fluid filled portion being filled with lubrication fluid so that the shaft portion and the sleeve portion rotate relatively to each other, the lubrication fluid filled portion including: a thrust dynamic pressure bearing portion; a radial dynamic pressure bearing portion comprised of the outer circumferential surface of the shaft portion, the inner circumferential surface of the sleeve portion, and the lubrication fluid filled therebetween; and a pump-in dynamic pressure generation portion being disposed between the thrust dynamic pressure bearing portion and the radial dynamic pressure bearing portion so as to generate pressure that causes the lubrication fluid to move toward the radial dynamic pressure bearing portion to reach a gap between the shaft portion and the sealed end of the insertion hole, which floats the rotor at a position where the shaft portion is opposed to the sealed end of the insertion hole, wherein the pump-in dynamic pressure generation portion is independent of the thrust dynamic pressure bearing portion and the radial dynamic bearing portion.