Rotary machine

Abstract

Provided is a rotary machine including: a shaft that rotates; a disc that has a substantially cylindrical hub fitted into the shaft and is provided so as to widen outward in a radial direction from a front end to a rear end of the hub; and an impeller having a plurality of blades provided on a surface of the disc. The hub has a tight fit section having an internal radius that is smaller than a radius of the shaft, and a loose fit section having an internal radius that is greater than the internal radius of the tight fit section. The loose fit section is provided on the front end side of the hub with respect to the tight fit section.

1 - 9 . (canceled) 
     
     
         10 . A rotary machine comprising:
 a shaft that rotates;   a disc that has a hub fitted into the shaft and is extended with the increasing distance toward outward in a radial direction from a front end to a rear end of the hub; and   an impeller having a plurality of blades provided on a surface of the disc, wherein   a rear surface of the disc is formed with a groove portion, wherein the groove portion is recessed toward the front end from the rear end so as to surround the hub, and   in the axial direction of the shaft, the hub is extended to a rear surface of the disc from a part of the most front end of the groove portion.   
     
     
         11 . The rotary machine according to  claim 10 , wherein
 a tight fit section is configured to be fitted to the shaft having an fastening margin therebetween.   
     
     
         12 . The rotary machine according to  claim 10 , wherein
 the hub protrudes to the rear side of the disc, in the axial direction of the shaft.   
     
     
         13 . The rotary machine according to  claim 10 , further comprising:
 a cover that is placed so as to be separated from the disc by a predetermined distance, wherein   the groove portion is formed to be recessed with respect to the front end of the cover.   
     
     
         14 . The rotary machine according to  claim 10 , wherein
 the thickness of the hub is constant at the rear end side of the groove portion, in the axial direction of the shaft.   
     
     
         15 . The rotary machine according to  claim 10 , wherein
 the thickness of the rear end of the tight fit section is larger than the thickness of the front end of the loose fit section, in the axial direction of the shaft.   
     
     
         16 . The rotary machine according to  claim 10 , wherein
 the hub is provided near the center of the half section of the impeller.   
     
     
         17 . The rotary machine according to  claim 10 , wherein
 the tight fit section is configured such that an fastening force is increased by a rotation of the shaft.   
     
     
         18 . The rotary machine according to  claim 10 , wherein
 in the state in which the shaft is rotated, the rear end of the hub tilts, and a tight fit section is fixed to the shaft.