Patent ID: 6781266
Filing Date: 2004-08-24
Classification: F16C,H02K

Abstract:
A spindle motor for use in a disk drive comprising:a shaft supporting a thrust plate at one end thereof; a sleeve surrounding the shaft and being rotatable relative to the shaft and supporting a hub on the outer surface thereof, the sleeve having a surface adjacent the thrust plate, and the sleeve cooperating with the shaft to define a journal bearing and with the thrust plate to define a first fluid dynamic thrust bearing; a counterplate welded to an upraised axial shoulder of the sleeve and having a surface located adjacent a surface of the thrust plate to define at least a second fluid dynamic thrust bearing; fluid within the first and second thrust bearings and the journal bearing supporting relative rotation of the shaft and sleeve; and a groove region defined in the shoulder of the sleeve radially aligned with the counterplate to radially weaken the sleeve.