Patent ID: 9435345
Filing Date: 2016-09-06
CPC Classification: F04D

Claim Text:
1. An impeller for an axial flow fan that is operable in a normal rotation and in a reverse rotation, the impeller comprising: a plurality of blades arranged in a circumferential direction, wherein each of the blades has: a first face that has a first three-dimensional shape and serves as a pressure surface during the normal rotation; a second face that has a second three-dimensional shape that is different from the first three-dimensional shape and serves as a suction surface during the normal rotation; a leading edge portion that connects the first face and the second face and is located at a front side during the normal rotation; and a trailing edge portion that connects the first face and the second face and is located at a rear side during the normal rotation, wherein the first face and the second face are configured to have a different cross-sectional shape with each other, wherein the leading edge portion and the trailing edge portion are configured to have a line-symmetric shape with respect to a center point of a chord length L, wherein each of the first face and the second face is defined to have a center portion and end portions that are arranged at each of two sides of the center portion and smoothly connected with the center portion, wherein each of the end portions of the first face is formed in an arc shape having a curvature radius R wherein the center portion of the first face is formed in an arc shape having a curvature radius R wherein each of the end portions of the second face is formed in an arc shape having a curvature radius R wherein the center portion of the second face is formed in an arc shape having a curvature radius R wherein the curvature radius R wherein the curvature radius R wherein the curvature radius R wherein the curvature radius R