Abstract: This invention provides a compact, flat axial fan which is not limited by the shape of an incorporated rotor magnet and ensures a sufficiently large air flow and wind pressure, wherein the slide (under) piece of a mold that forms the under-molding portions of the vanes of the impeller of the axial fan is pulled out while being twisted (while performing a helical motion) in the direction of central axis of the base portion of the impeller, so that the mold can be formed simple to realize a multi-cavity mold, and the vanes can be formed into an ideal form by setting vane angles depending on different rotating peripheral velocities of the vanes, so that air can be supplied form the under-molding portions of the vanes to the vanes on the outer circumferential side during rotation of the impeller, a method of manufacturing an impeller for the axial fan, and a mold for manufacturing the impeller of the axial fan.

Abstract: This invention provides a compact, flat axial fan which is not limited by the shape of an incorporated rotor magnet and ensures a sufficiently large air flow and wind pressure, wherein the slide (under) piece of a mold that forms the under-molding portions of the vanes of the impeller of the axial fan is pulled out while being twisted (while performing a helical motion) in the direction of central axis of the base portion of the impeller, so that the mold can be formed simple to realize a multi-cavity mold, and the vanes can be formed into an ideal form by setting vane angles depending on different rotating peripheral velocities of the vanes, so that air can be supplied form the under-molding portions of the vanes to the vanes on the outer circumferential side during rotation of the impeller and a method of manufacturing an impeller for the axial fan.