Patent ID: 6375357
Filing Date: 2002-04-23
Classification: F16C,G11B,H02K

Abstract:
A spindle motor comprising:a fixed frame having a cylindrical holder; a cylindrical bearing sleeve having a hydrodynamic bearing surface on an inner peripheral face thereof, and disposed in the cylindrical holder; a rotary shaft rotatably supported on an inner peripheral face of the fixed bearing sleeve via a lubricating fluid provided therebetween; a rotary hub secured to a first end of the rotary shaft; an annular thrust plate integrally joined to a second end of the rotary shaft to constitute a thrust hydrodynamic bearing portion in the bearing sleeve; a disk-like counter plate for closing an opened end portion of the bearing sleeve in which the thrust hydrodynamic bearing portion is provided; and a relief portion formed on one end portion of joining surfaces of the rotary shaft and the thrust plate so as to recess in an axial direction of the rotary shaft at which the rotary shaft and the thrust plate are welded to be integrated with each other.