Abstract: Disclosed is a turbofan which includes a hub coupled with a rotational shaft of a driving device, a plurality of blades installed at a circumference of the hub radially, and a shroud at an opposite side to the hub so as to be coupled with a plurality of the blades wherein the blades are placed between the shroud and the hub, and wherein the hub, blades, and shroud are formed in one body and wherein the shroud comprises a first extension protruding to extend from a coupling part with a leading edge of each of the blades in an inward radial direction of the rotational shaft and a second extension extending straightly from the first extension in a direction of the rotational axis toward a side opposite to the hub.

Abstract: A blade part in a turbofan includes a hub coupled with a rotating axis of a driving part, a plurality of blades arranged radially at a circumferential part of the hub, and a shroud coupled with a plurality of the blades and arranged so as to confront the hub wherein the blades lie between the hub and the shroud, and wherein each of the blades form an airfoil constructed with a top camber line defined by an NACA 4-digit airfoil and a bottom camber line lying closer to the top camber line than a bottom camber line defined by the NACA 4-digit airfoil.

Abstract: A turbo fan comprises: a hub coupled to a rotational shaft of a driving device; a plurality of blades installed on an outer circumference of the hub in a radial direction; and a shroud connected to the plurality of blades on opposite side of the hub centering around the blades; wherein a leading edge of the blade comprises: a connection part which is connected to the shroud; an extension part which is extended as a straight line parallelly with the rotational shaft from the hub; and a curved surface part which is formed as a convex curved surface between the extension part and the connection part.

Abstract: A turbo fan comprises: a hub coupled to a rotational shaft of a driving device; a plurality of blades installed on an outer circumference of the hub in a radial direction; and a shroud connected to the plurality of blades on opposite side of the hub centering around the blades; wherein a leading edge of the blade comprises: a connection part which is connected to the shroud; an extension part which is extended as a straight line parallelly with the rotational shaft from the hub; and a curved surface part which is formed as a convex curved surface between the extension part and the connection part.

Abstract: Disclosed is a blade part in a turbofan, which includes a hub coupled with a rotating axis of a driving part, a plurality of blades arranged radially at a circumferential part of the hub, and a shroud coupled with a plurality of the blades and arranged so as to confront the hub wherein the blades lie between the hub and the shroud, and wherein each of the blades form an airfoil constructed with a top camber line defined by an NACA 4-digit airfoil and a bottom camber line lying closer to the top camber line than a bottom camber line defined by the NACA 4-digit airfoil, thereby enabling to cost and time of product.

Abstract: Disclosed is a turbofan which includes a hub coupled with a rotational shaft of a driving device, a plurality of blades installed at a circumference of the hub radially, and a shroud at an opposite side to the hub so as to be coupled with a plurality of the blades wherein the blades are placed between the shroud and the hub, and wherein the hub, blades, and shroud are formed in one body and wherein the shroud comprises a first extension protruding to extend from a coupling part with a leading edge of each of the blades in an inward radial direction of the rotational shaft and a second extension extending straightly from the first extension in a direction of the rotational axis toward a side opposite to the hub.