Turbofan and indoor unit of air-conditioning apparatus including the same

摘要

Blades forming a turbofan included in an indoor unit each have, in a blade outer-circumferential surface of the blade and near a blade rear-edge portion, a plurality of rear-edge horizontal grooves extending horizontally (in a plane perpendicular to a center of rotation) with predetermined lengths L2 reaching the blade rear-edge portion. The rear-edge horizontal grooves are each a combination of a groove recessed portion provided with a predetermined depth in the blade outer-circumferential surface and a groove wrapping portion continuous with the groove recessed portion and provided at the terminal end of the blade rear-edge portion. The rear-edge horizontal grooves are provided in a region extending upward from the main plate defined by a distance H1 and in a region extending downward from the shroud defined by a distance H2.

主权项

1. A turbofan comprising a disc-shaped main plate having a boss projecting in a predetermined region containing a center of rotation; a ring-shaped shroud facing the main plate; and a plurality of blades each having two ends thereof joined to the main plate and the shroud, respectively,
wherein a blade rear edge of each of the plurality of blades resides on a virtual cylinder defined by an outer circumference of the main plate and an outer circumference of the shroud, a blade front edge of each of the plurality of blades resides at a position nearer to the center of rotation than the blade rear edge, and a virtual line connecting the blade rear edge and the blade front edge is angled with respect to a radial line extending from the center of rotation, wherein a blade outer-circumferential surface, that is a surface of each of the plurality of blades farther from the center of rotation, has a plurality of rear-edge horizontal grooves having predetermined lengths reaching the blade rear edge, wherein the rear-edge horizontal grooves extend perpendicularly to the center of rotation and wrap around an end of the blade rear edge to a blade inner-circumferential surface that is a surface of each of the plurality of blades nearer to the center of rotation, and wherein the blade outer-circumferential surface of each of the plurality of blades has inter-groove surface portions extending between adjacent ones of the rear-edge horizontal grooves, and one of the inter groove surface portions is larger than other inter-groove surface portions.