Patent ID: 8834121
Filing Date: 2014-09-16
Classification: F04D,F05D

Abstract:
1. A turbo fan comprising: a disk-shaped main plate provided with a rotation center at the center and a projecting boss formed in the vicinity of the rotation center; a cylindrical shroud arranged opposite to the main plate and provided with a diameter expanded portion whose inner diameter becomes more expanded, the closer it becomes to the main plate; and a plurality of blades with one end and the other end joined to the main plate and the shroud respectively; wherein a blade rear edge of each blade is located on a virtual cylinder formed by an outer periphery of the main plate and an outer periphery of the shroud, a blade front edge of each blade is located closer to the rotation center than the blade rear edge of the blade, and a virtual line which connects the blade rear edge and the blade front edge is inclined with respect to a radial line of the main plate from the rotation center, wherein a blade outer face, which is a face away from the rotation center of the blade, is formed on a projecting face projecting in a direction away from the rotation center, wherein the blade front edge is divided into a main-plate-side blade front edge close to the main plate, a shroud-side blade front edge close to the shroud, and a projecting blade front edge formed between the main-plate-side blade front edge and the shroud-side blade front edge, wherein in a range of the main-plate-side blade front edge close to the main plate, a main-plate-side front-edge skirt portion is formed to distance away from the blade rear edge and incline away from the rotation center the closer it becomes to the main plate, wherein in a range farther away from the main plate than the main-plate-side front-edge skirt portion, a main-plate-side front-edge vertical portion perpendicular to the main plate is formed, wherein in a range farther away from the main plate than the main-plate-side front-edge vertical portion, with respect to the main-plate-side front-edge vertical portion, a main-plate-side front edge inclined portion is formed to distance away from the blade rear edge and incline away from the rotation center the farther it becomes to the main plate, wherein a range closer to the main plate than a projecting front-edge end point of the projecting blade front edge continuing from the main-plate-side front edge inclined portion distances away from the blade rear edge and distances away from the rotation center the farther it becomes to the main plate, and wherein a range farther away from the main plate than the projecting front edge end point of the projecting blade front edge continuing to the shroud-side blade front edge becomes closer to the blade rear edge and is distanced away from the rotation center the farther it becomes to the main plate.