Minebea Company, Limited

Minebea Kabushiki-kaisha

Yasuhiro Mouri

Toshisada Koyama

Shinichi Mori

A pivot bearing includes a stepped shaft having an enlarged diameter shaft portion and a reduced diameter shaft portion; a plurality of balls of a lower row are interposed between the enlarged diameter shaft portion and a sleeve outer ring surrounding the enlarged diameter shaft portion; a ball bearing including inner and outer rings and a plurality of balls interposed therebetween is provided around the reduced diameter shaft portion so that the inner ring is secured around the reduced diameter shaft portion while applying an appropriate pre-load on the upper end surface of the inner ring, and the outer ring is urged to contact the lower surface thereof intimately onto the upper surface of the sleeve outer ring. The pivot bearing has a reduced number of parts, is facilitated in incorporation into a swing arm, and is expected to be manufactured at a reduced cost.

Pivot bearing for a swing arm of a hard disk drive device

A pivot bearing of the present invention comprises inner rings, outer rings surrounding the inner rings and rollable balls arranged between the inner and outer rings. This pivot bearing does not have a sleeve which is provided on the outer rings of a conventional pivot bearing. Each of the outer rings is made thicker substantially by the thickness of the sleeve of the conventional pivot bearing than the outer rings of the conventional pivot. The other components of the pivot bearing according to the present invention than the outer bearings use commercially available components or standardized components manufactured in the ordinary manufacturing line at ball bearing manufacturers' factories. Thus, a simple, inexpensive and precise pivot bearing can be manufactured.

Pivot bearing

A bearing device is used as a bearing for a pivot of a head stack assembly to thereby make a hard disc drive thin. Widths of first and second inner races 12a and 13a are set to be smaller than the widths of first and second outer races 12b and 13b. Even if first and second bearings 12 and 13 (outer races 12b and 13b) are mounted on a shaft 9 in contact with each other, a space S is formed between the first and second inner races 12a and 13a. From this structure, in the case where a pre-pressure is applied to the second inner race 13a, it is possible to adjust the pre-pressure in a wide range. In the prior art, it has been necessary to provide an annular projection or a spacer for keeping a space for application of the pre-pressure. However, the present invention makes possible to dispense with the annular projection or the spacer. Corresponding to this, the width of the bearing device 10 is shortened. Finally, the thickness of the pivot portion of the swing arm is decreased to thereby make the hard disc drive thin.

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Miyota-machi, Japan

Yasuhiro Mouri