| 摘要 |
PURPOSE:To increase a cooling air amount, by forming, at a turbo fan, a plurality of blades and a shroud ring which is at the front end surfaces of the blades, and also, forming at the suction side end portions of the blades cross section circular portions whose diameters are larger than the blade thickness, and thus, preventing the occurrence of eddy currents at the suction side end portions of the blades. CONSTITUTION:At a turbo fan 5, a bulge portion is formed at the front face center portion of an impeller 8, and a plurality of blades 12 are provided in a radiation direction at regular intervals at the front face end perimeter edge portion of the impeller 8. Also, at the suction side end portion of each blade 12, a cross section circular portion 12a whose diameter is larger than the thickness of the blade 12, is formed, and in addition, at the front end surfaces of the blades 12, a shroud ring 13 is formed in a concentric state against a crank shaft 2. As a result, the turbo fan 5 is rotated, and outer air is made to flow in a blade 12 direction through the air intake opening 7a of an engine cover along the slope of the bulge portion of the impeller 8, and a smooth rectification is done along the shroud ring 13, and also, the occurrence of eddy currents at the suction side end portions of the blades 12 is prevented. |
