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   the hub comprises a tight fit section and a loose fit section,   the tight fit section is provided on the rear end of the hub, and is configured to be fitted to the shaft having an fastening margin therebetween,   the loose fit section is provided on the front end of the hub with respect to the tight fit section, and   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.   
     
     
         11 . 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.   
     
     
         12 . The rotary machine according to  claim 10 , wherein
 the tight fit section is configured such that an fastening force is increased in at least a rear side of the tight fit section by a rotation of the shaft.   
     
     
         13 . 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   the hub comprises a tight fit section and a loose fit section,   the tight fit section is provided on the rear end of the hub,   the loose fit section is provided on the front end of the hub with respect to the tight fit section,   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 state in which the shaft is rotated, the rear end of the hub tilts, and the tight fit section is fixed to the shaft.