Abstract: An improved bearing for a heat dissipation fan has an oil chamber for containing lubricant. The oil chamber has a sidewall extending between one open end and one closed end. The closed end is perforated with a through hole, and an edge of the sidewall at the open end is partially recessed to form at least one notch. An external surface of the sidewall is partially recessed along an elongate direction to form at least one oil slot aligned with the notch, the recessed external sidewall is further perforated with a through hole. An O-ring is disposed adjacent to the closed end of the oil chamber. The O-ring has an aperture aligned with the through hole of the closed end. An axial column is inserted into the oil chamber through the aperture of the O-ring and the through hole of the closed end. An external sleeve is used for receiving the oil chamber therein.