Rotary machine

A rotary machine comprising:

• a rotating shaft that is configured to rotate around a center axis by a rotation driving force input from an outside;
• a pair of radial bearings for rotatably supporting the rotating shaft around the center axis;
• a thrust bearing for restraining movement of the rotating shaft in a center axis direction;
• impellers that integrally rotate with the rotating shaft and are fixed to outermost positions of the rotating shaft, in the center axis direction, at positions separated from the radial bearings in the center axis direction, wherein the radial bearings are arranged only at positions sandwiched between the impellers in the center axis direction;
• and
• a pair of additional masses that are each fixed to the rotating shaft at a position separated from both the radial bearings and the impellers in the center axis direction, and that each apply a load to an entire circumference of the rotating shaft so as to move a position of an amplitude increase region where an amplitude in a radial direction of the rotating shaft starts to increase, wherein
• the impellers are fixed to the rotating shaft on outer sides of the pair of the radial bearings in the center axis direction,
• each of the pair of the additional masses is fixed to the rotating shaft between one of the impellers and one of the radial bearings in the center axis direction, and
• the thrust bearing supports a load that acts in the center axis direction with respect to the rotating shaft via a disc-shaped thrust collar that projects an outer side of the rotating shaft in the radial direction and the thrust bearing is disposed on an inside of the pair of the radial bearings in the center axis direction.