Sleeve, fluid dynamic pressure bearing including the sleeve, spindle motor including the fluid dynamic pressure bearing and electronic equipment including the spindle motor

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.