Abstract: A lubrication structure for a rolling bearing assembly of low manufacturing cost, high speed and the environment-friendly is provided. An inclined surface portion is provided in an outer diametric surface of an inner ring of the bearing assembly, and a grease tank having a grease reservoir is arranged adjacent to an outer ring of the rolling bearing assembly. A base oil transfer medium for moving a base oil in the grease by capillary phenomenon is provided within the grease reservoir, and one end thereof contacts the inclined surface portion. Accordingly, the base oil within the grease reservoir adheres to the inclined surface portion through the base oil transfer medium, and the base oil adhering to the inclined surface portion is supplied to the bearing assembly utilizing surface tension of the base oil and the flow of the base oil induced upon rotation of the inner ring.

Abstract: A cage is made of a magnesium alloy, the magnesium alloy being molded by means of injection molding using a mold including a cavity portion having a shape corresponding to a shape of the cage, and has a shape resulting from being forcedly extracted from the mold. As a result, a cage made of a magnesium alloy of high strength and having a shape resulting from being forcedly extracted from a mold, a rolling bearing including the cage, a machine tool including the rolling bearing, and a method of manufacturing the cage can be provided.