SLEEVE, FLUID DYNAMIC PRESSURE BEARING INCLUDING THE SLEEVE, SPINDLE MOTOR INCLUDING THE FLUID DYNAMIC PRESSURE BEARING AND ELECTRONIC EQUIPMENT INCLUDING THE SPINDLE MOTOR

摘要

A porous oil-impregnated sleeve is used for a fluid dynamic pressure bearing. The sleeve includes an inner surface, a first axial end face, a first recessed portion, and a first dynamic pressure generating groove. The first recessed portion is positioned on the other side of a line segment, which connects one-side end portion of the inner surface with an inner end portion of the first axial end face, in a cross-section including the central axis. A bottom portion of the first recessed portion, which has the longest distance between itself and the line segment, is positioned closer to the other side than a bottom portion of the first dynamic pressure generating groove in the axial direction.

主权项

1. A porous oil-impregnated sleeve that is used for a fluid dynamic pressure bearing and extends around a central axis, the porous oil-impregnated sleeve comprising:
an outer surface; an inner surface; a first axial end face that is positioned on one side in an axial direction; a first recessed portion that is a connecting surface connecting the inner surface with the first axial end face; and a first dynamic pressure generating groove that is positioned on the first axial end face and is recessed toward the other side, wherein the sleeve is filled with a lubricant, the first recessed portion is positioned on the other side of a line segment, which connects one-side end portion of the inner surface with an inner end portion of the first axial end face, in a cross-section including the central axis, and a bottom portion of the first recessed portion, which has the longest distance between itself and the line segment, is positioned closer to the other side than a bottom portion of the first dynamic pressure generating groove in the axial direction.