| 摘要 |
PROBLEM TO BE SOLVED: To provide means for reducing flexural stress on a radial outside portion of a disk without giving ill effects to both centrifugal force and the stability of a rotor when increasing the thickness of a blade to secure the strength against the centrifugal force.SOLUTION: An impeller includes a discoidal disk 101 integrally and rotatably mounted on a rotating shaft, and a plurality of blades 102 provided in the peripheral direction while being protruded from the surface of the disk 101, and each having a cavity 103 at least in a radial outside portion for suppressing the weight, wherein a vent hole 101d is provided which passes through the disc 101 to communicate the cavities 103 with the reverse side of the disk 101 and has a smaller diameter than the cavity 103. |
