Other

Daido Tokushuko Kabushiki Kaisha

Jun Yatazawa

Narito Shimizu

Takahiro Sanada

Tatsuo Hisada

Yoshiro Sakai

Shigeru Iwasa

Makio Kato

Described is a method of manufacturing a crown-shaped component having a plurality of axially extending protrusions which are formed at an end of a cylindrical portion The method comprises the steps of: upsetting the cylindrical portion into a cylindrical blank having protrusions arrayed on and along the inner circumferential surface of a remaining part annealing the cylindrical blank; removing the remaining part by cutting; and subjecting the resultant blank to a shot blasting process, whereby a magnetic characteristic of the resultant crown-shaped component is improved.

Method of manufacturing a crown-shaped component

A bearing mechanism eliminates the need for lubricating oil, is capable of generating enough radial dynamic pressure even in lower-speed regions, and yet can be easily surface-machined for the generation of radial dynamic pressure and manufactured with low cost. In at least either one of an outer circumferential surface of a first member or an inner circumferential surface of a second member (hereinafter, referred to as roughened surface), the two circumferential surfaces being opposed to each other with a bearing gap G therebetween, dot-like minute dips and bumps are formed dispersedly, by which the surface is roughened so that its center-line mean roughness is controlled within a range of 0.1 &mgr;m-1.0 &mgr;m. With this arrangement, since enough radial dynamic pressure can be generated at a relatively low rotational speed, time duration of a dynamic-pressure insufficiency upon a start-up or halt of the rotating mechanism is shortened so that members in the bearing part can be made less liable to wear.

Bearing mechanism, hard disk drive mechanism and polygon mirror drive mechanism using the bearing mechanism, and method for manufacturing herringbone groove portions of dynamic-pressure bearing

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Toukai, Japan

Jun Yatazawa