Fluid bearing apparatus including dynamic pressure grooves with striations, spindle motor, and disk drive apparatus

摘要

A fluid bearing apparatus includes a stationary member and a rotating member. A bearing surface of the stationary member and a bearing surface of the rotating member are arranged opposite to each other with a minute gap intervening therebetween. A lubricating fluid is arranged in the minute gap. At least one of the bearing surfaces includes a dynamic pressure groove, and a plurality of striations defined in a bottom portion of the dynamic pressure groove. Each of the dynamic pressure groove and the striations is arranged to extend in a direction at an angle greater than 0° to a circumferential direction. An angle defined between each striation and the circumferential direction is equal to or smaller than an angle defined between the dynamic pressure groove and the circumferential direction. Thus, an improvement in a force of dynamic pressure at the dynamic pressure groove is achieved.

主权项

1. A fluid bearing apparatus comprising:
a stationary member including a bearing surface; and a rotating member arranged to rotate about a rotation axis with respect to the stationary member, and including a bearing surface; wherein the bearing surface of the stationary member and the bearing surface of the rotating member are arranged opposite to each other with a minute gap intervening therebetween, a lubricating fluid being arranged in the minute gap; at least one of the bearing surfaces includes:
a dynamic pressure groove; anda plurality of striations defined in a bottom portion of the dynamic pressure groove; each of the plurality of striations is a groove recessed in a depth direction of the dynamic pressure groove; a depth of each striation as measured from an edge portion of the striation is smaller than a depth of the dynamic pressure groove; each of the dynamic pressure groove and the plurality of striations is arranged to extend in a direction at an angle greater than 0° to a circumferential direction; an angle defined between each striation and the circumferential direction is equal to or smaller than an angle defined between the dynamic pressure groove and the circumferential direction; and the angle defined between the dynamic pressure groove and the circumferential direction is in a range of 10° to 30° both inclusive.