Impeller, impeller blade wheel, air-blowing device, and method of manufacturing air-blowing device

An impeller that rotates about a vertically extending central axis, the impeller comprising:

• a base portion that extends out in a direction perpendicular to the central axis;
• and
• blades arranged on an upper surface of the base portion at spaced intervals in a circumferential direction;
• wherein
• the base portion includes, on an outer side thereof in a radial direction, an irregular portion that includes:
• one or more first irregular regions including first recessed portions with a same shape and first projecting portions with a same shape, the first recessed portions and the first projecting portions being alternately arranged one by one;
• a second irregular region located between end portions of the one or more first irregular regions and including a second recessed portion with a shape different from that of the first recessed portions and a second projecting portion with a shape different from the first projecting portions;
• and
• a third irregular region including at least one of a third recessed portion with a shape different from that of the first recessed portions and the second recessed portion and a third projecting portion with a shape different from the first projecting portions and the second projecting portion;
• the first projecting portions rind the second projecting portion include pairs of side surfaces that are provided on opposing ends of the first projecting portions and the second projecting portion in the circumferential direction;
• ones of the pairs of side surfaces of the first projecting portions and the second projecting portion which correspond to front sides of the first projecting portions and the second projecting portions in a rotation direction of the impeller are inclined with respect to the circumferential direction;
• other ones of the pairs of side surfaces of the first projecting portions and the second projecting portion which correspond to rear sides of the first projecting portions and the second projection portion in the rotation direction of the impeller are perpendicular to the circumferential direction;
• and
• widths in the circumferential direction of each of the first projecting portions and the second projecting portion at end portions outwardly away from the base portion are narrower than widths in the circumferential direction of each of the first projecting portions and the second projecting portion adjacent to the base portion.