DYNAMIC PRESSURE BEARING, SPINDLE MOTOR WITH DYNAMIC PRESSURE BEARING, AND DISC DRIVING DEVICE USING SPINDLE MOTOR

摘要

PROBLEM TO BE SOLVED: To discharge bubbles collected between a thrust bearing part and a radial bearing part. SOLUTION: Pump-in type spiral grooves are formed on a thrust bearing part as dynamic pressure generating grooves, an axially unbalanced herringbone groove row is formed on the radial bearing part as the dynamic pressure generating grooves, and the oil is continuously held between the thrust bearing part and the radial bearing part. At least one of the spiral grooves formed on the thrust bearing part is elongated to an inner side in the radial direction with respect to the other spiral grooves, with a wide width in the circumferential direction. COPYRIGHT: (C)2004,JPO&NCIPI