Patent ID: 6038205
Filing Date: 2000-03-14
Classification: G11B,H02K

Abstract:
A spindle motor comprising:a fixed journal;a hub for loading disks;a ball bearing for rotatably supporting said hub;an annular member fixed on one of said fixed journal and said hub;said fixed annular member being configured to create a small space with said hub or said fixed journal which oppsite the one on which said annular member is fixed;wherein when L1 is the dimension of a space between a top surface of a top disk and a surface of a member facing said top surface of said top disk, and L2 is the dimension of a space between a bottom surface of a bottom disk and a surface of a member facing said bottom surface of said bottom disk, said annular member has grooves for generating air flow directed toward the space of longer dimension, one of said dimensions L1 and L2;said annular member being arranged with respect to said ball bearings in an axial direction of said fixed journal, and being arranged close to the space created between the top surface of said top disk and the surface of the member facing said top surface of said top disk;said annular member being fixed to said hub; when the relation between said L1 and L2 is L1>L2, said annular member having grooves on an end surface thereof on said ball bearing side for generating an air flow directed inwardly in the radial direction of said fixed journal; when L1<L2, said annular member having grooves on an end surface thereof on said ball bearing side for generating an air flow directed outwardly in a radial direction.