Patent ID: 6137196
Filing Date: 2000-10-24
Classification: G11B,H02K

Abstract:
A motor for driving a magnetic disk, comprising:a center pole shaft having a laminated core;a flange having a dish-formed recess portion providing a pillar having a step portion in a center of the flange;a stator generating a revolving magnetic field and fixed to the flange;exciting magnetic poles having a permanent magnet disposed around the stator in a confronting relationship therewith;a rotor frame having a cup form, the exciting magnetic poles located on an inner side of a lower portion of the rotor frame and rotatably held on the center pole shaft in a cantilevered manner supporting the magnetic disk;a noise cutoff layer blocking noise and interposed between an inside of the stator and the center pole shaft; anda noise blank sheet made of a porous material and having a positioning step portion positioning the laminated core in the center of the noise blank sheet and the positioning step portion being extended upward, wherein the noise blank sheet fixed on the step portion and interposed between the stator and the flange and the positioning step portion is in the noise cutoff layer.