US Patent 11473429 Impeller and method of manufacturing the same

An impeller including a hub surface and a plurality of blades protruding from the hub surface. Each of the plurality of blades has a pressure surface located on a leading side of the rotation direction and a suction surface located on a trailing side of the rotation direction. Each of the plurality of blades is provided with a plurality of first concave surfaces at a boundary between the pressure surface and the hub surface, and one second concave surface at a boundary between the suction surface and the hub surface. At least two different first concave surfaces having different concave radii in cross section are included in the plurality of first concave surfaces. A first concave radius that is the largest among the different concave radii is identical to a second concave radius that is a concave radius of the second concave surface in cross section.