Patent ID: 6356408
Filing Date: 2002-03-12
Classification: F16C,G11B,H02K,Y10T

Abstract:
A spindle motor used in an information storage apparatus at least to reproduce information from a rotating disk storage, comprising:a member which forms a part of a case on which the spindle motor is installed; a rotary axis; a bearing device which supports said rotary axis to be able to rotate against said member; a cup-shaped hub on which to install the disk storage, having a motor to rotate the disk storage and said bearing device inside thereof, and a passage for air circulation, which connects the inside of said hub to outside thereof; wherein said bearing device comprises a seal ring, a first radial bearing, a permanent magnet, a second radial bearing and a thrust bearing arranged along said rotary axis from a side of an opening; said first and second radial bearings are dynamic pressure sliding bearings; magnetic fluid is used as a lubricant for said first and second radial bearings; said disk storage is a plurality of magnetic disks stacked on said hub in the direction of the axis of rotation; a first spiral groove is formed either in the opening of said bearing device or on a surface of said hub opposite to said opening; a second spiral groove is formed on an inner surface of a seal ring provided at a side of said opening; said passage is provided with said hub as a penetration hole in the axial direction that connects the inside and the outside of the hub; and a filter made of a fluorine resin or comprising fibers coated with a fluorocarbon resin is positioned in said penetration hole; wherein said second spiral groove forces the fluid leaked from said bearing device back into said bearing device.