Fluid dynamic bearing apparatus

Abstract

The purpose of the invention is a bearing member comprising highly accurate dynamic pressure generating portions and stably manufacturable at low cost. Dynamic pressure grooves (8a1) and (8a2) as the dynamic pressure generating portions are formed in the inner peripheral surface of an electroformed part (10) by electroforming, and the electroformed part (10) is inserted and the bearing member (8) is injection-molded with a resin. A shaft member (2) is inserted to the inner periphery of the bearing member.

Description

technical field [0001] The invention relates to a bearing arrangement for rotatably supporting a shaft member by the action of hydrodynamic pressure generated in a bearing gap. This type of bearing device is called a "fluid dynamic bearing device" and is suitable for use on information devices such as magnetic disk devices such as HDD and FDD, optical disk devices such as CD-ROM / RAM, or such as MD / MO, etc. in a spindle motor in a magneto-optical disk device), in a polygon scanner motor in a laser beam printer (LBP) or the like, or in a small motor in an electronic device such as an axial fan. Background technique [0002] In a fluid dynamic bearing device, the shaft member is usually supported in the radial direction without being in contact with the bearing member by the action of dynamic pressure of fluid generated in the radial bearing gap. In order to generate the dynamic pressure action of the fluid in the radial bearing gap, in a predetermined area of ​​at least any o...

AI Technical Summary

Problems solved by technology

In the above-mentioned method of forming dynamic pressure grooves by forming roll pressing, the shape of the grooves tends to change due to the characteristics of the method, and it is difficult to stably mass-produce high-precision grooves at low cost

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