Spindle motor and hard disk drive including the same

A spindle motor comprising:

• a second thrust member fixedly installed on a base member;
• a shaft fixedly installed on the second thrust member;
• a sleeve disposed above the second thrust member and installed to be rotatable with respect to the shaft;
• a rotor hub coupled to the sleeve to thereby be rotated together with the sleeve;
• and
• a first thrust member disposed above the sleeve and fixedly installed on the shaft,
• wherein the sleeve includes a circulation hole penetrating therethrough in an axial direction,
• the sleeve and the first thrust member include a first thrust bearing formed therebetween and the sleeve and the second thrust member include a second thrust bearing formed therebetween, and
• an area by which an upper end portion of the circulation hole in the axial direction is overlapped with the first thrust bearing is larger than an area by which a lower end portion of the circulation hole in the axial direction is overlapped with the second thrust bearing.