Fan, molding die, and fluid feeder

A fan comprising a plurality of blade portions arranged spaced apart from each other in a circumferential direction, each blade portion having a blade surface including a pressure surface disposed on a rotational direction side of the fan and a suction surface disposed on a back side of said pressure surface, wherein

• when cut along a plane orthogonal to a rotation axis of the fan, said blade portion has an inner edge portion at which a center line between said pressure surface and said suction surface intersects an inner peripheral-side blade tip, and an outer edge portion at which the center line intersects an outer peripheral-side blade tip,
• as the fan is rotated, a fluid flow is produced on said blade surface to flow between said inner edge portion and said outer edge portion,
• when an angle between a straight line passing through a rotational center of the fan and said outer edge portion and a tangent of said center line at said outer edge portion is defined as an outer peripheral blade tip angle, and an angle between a straight line passing through the rotational center of the fan and said inner edge portion and a tangent of said center line at said inner edge portion is defined as an inner peripheral blade tip angle,
• a plurality of said blade portions are provided such that said outer peripheral blade tip angle and said inner peripheral blade tip angle are each equal among a plurality of said blade portions, and
• a plurality of said blade portions include a first blade portion and a second blade portion in which when they are rotated around the rotation axis of the fan and overlapped on one blade portion, one of said inner edge portion and said outer edge portion is disposed to be coincident with each other, and the other of said inner edge portion and said outer edge portion is disposed to be displaced from each other.