Abstract: Each of a plurality of blades of a turbofan includes a thick wall portion, a thin wall portion and a stepped portion. The stepped portion is formed between the thick wall portion and the thin wall portion. A plate thickness of the stepped portion is progressively decreased toward a positive pressure surface of the blade in a direction that is directed from the thick wall portion toward the thin wall portion. In the blade, a first curved surface forms a negative pressure surface of the thick wall portion, and a second curved surface forms a negative pressure surface of the thin wall portion while the second curved surface is located on a side of the first curved surface where the positive pressure surface of the blade is placed, and a negative pressure surface of the stepped portion connects between the first curved surface and the second curved surface.

Abstract: A centrifugal multiblade fan includes a rotatable shaft, blades, a side shroud, and a main shroud. A front edge has a shape inclined radially outward in a direction from the main shroud toward the side shroud. When viewed from an axial direction, a corner part on a positive pressure surface-side is located on a tangential line of a positive pressure surface reference curve at a positive pressure surface side reference corner part, and when viewed from the axial direction, a curvature radius of a negative pressure surface becomes larger in a direction from the side shroud toward the main shroud.

Abstract: A centrifugal multiblade fan includes a rotatable shaft, blades, a side shroud, and a main shroud. A front edge has a shape inclined radially outward in a direction from the main shroud toward the side shroud. When viewed from an axial direction, a corner part on a positive pressure surface-side is located on a tangential line of a positive pressure surface reference curve at a positive pressure surface side reference corner part, and when viewed from the axial direction, a curvature radius of a negative pressure surface becomes larger in a direction from the side shroud toward the main shroud.