Rotor, rotary machine, and method for assembling rotor

A rotor comprising:

• a shaft extending in an axial direction in which an axis extends centered on the axis;
• a connecting shaft connected to an end portion of the shaft on a first side in the axial direction and having a screw part formed at a tip portion of the connecting shaft;
• an impeller including an impeller body formed in a disc-like shape centered on the axis and an insertion hole which is formed in a center portion of the impeller body passing through in the axial direction and through which the connecting shaft is inserted;
• a sleeve having a tubular shape that is disposed at a position on a second side opposite to the first side in the axial direction relative to the impeller and is fixed to the shaft in such a manner as to cover the shaft on an outer side in a radial direction based on the axis relative to the shaft;
• and
• a nut that is disposed on the first side in the axial direction relative to the impeller, and pinches and fixes the impeller together with the sleeve in the axial direction by being fastened to the screw part, wherein
• a position of a sleeve end face of the sleeve facing the first side in the axial direction and a position of an impeller end face of the impeller facing the second side in the axial direction are constrained mutually in a circumferential direction around the axis and the radial direction in a state of the sleeve end face and the impeller end face being in contact with each other.