FLUID DYNAMIC PRESSURE BEARING, SPINDLE MOTOR USING THE FLUID DYNAMIC PRESSURE BEARING AND RECORDING DISK DRIVE UNIT USING THE SPINDLE MOTOR

摘要

A shaft body 2 of a fluid dynamic bearing having a flange portion 4 at one end is supported rotatably via radial direction micro clearances by the sleeve 5 having a dynamic pressure generating groove 11 on the inner peripheral portion. A flange portion 4 is inserted between the lower end surface of the sleeve 5 and end plate 7. A dynamic pressure generating groove 12 is formed on the lower end surface of sleeve 5, and a dynamic pressure generating groove 13 is formed on the upper surface of the endplate 7. The lower end surface of the sleeve 5 and the upper surface of the flange portion 4, and the upper surface of the end plate 7 and the lower surface of the flange portion 4 are facing each other via respective thrust direction micro clearances. Sleeve 5 is inserted into the case 6 such that the upper end surface is projected from the upper end surface of the case 6. The outer peripheral face of the sleeve is fixed at the upper end of the case 6 by filling an adhesive in an adhesive reservoir formed between the sleeve 5 and the case 6. Adhesion and leakage of the adhesive to the locations other than the specified locations to be filled can be prevented, the number of manufacturing steps for the fluid dynamic bearing is reduced, quality is maintained, mass procucibility is improved and low cost production is achieved.