Patent ID: 8251666

Claim:
A forward-swept shaped blade for a fan, comprising: a blade body made of a synthetic resin; and a metallic insert used for insert molding of the blade body and mounted to a mounting arm of a spider forming the fan, wherein: a shape of the entire insert is not homothetic with a shape of the entire blade; a bulging portion is provided on the insert at a corner on an outer side in a radial direction and a forward side in a rotary direction, the bulging portion bulging toward both the outer side in the radial direction and the forward side in the rotary direction, a bulging region of the bulging portion that most prominently bulges toward the outer side in the radial direction is located to be forward in the rotary direction relative to a mounting center of the insert and the mounting arm along the radial direction, the insert extends further toward the outer side in the radial direction at the bulging region than at a portion of the insert along the mounting center, a bulging length of the bulging portion relative to a body portion of the insert along the mounting center is set to be within a range of 2 to 10 percent of an average length of the entire insert, a bulging width of the bulging portion relative to the body portion in a direction perpendicular to the mounting center is set to be within a range of 5 to 30 percent of an average width of the entire insert, a first straight section perpendicular to the mounting center and a second straight section extending along the mounting center are provided on an outer circumference of the insert, and an outer circumference of the bulging portion comprises a first curved section of a first radius that is continuously connected with the first straight section and is dented inward in the radial direction, a second curved section of a second radius that is continuous with the first curved section and is protruded outward in the radial direction, and a third straight section tangent to the second curved section.