Exhaust-gas turbocharger

A rotor (12) of an exhaust-gas turbocharger (1), having

• a shaft (2), which has an outside diameter (A2);
• a turbine wheel (5), which is fastened to the shaft (2);
• and
• a heat throttle (8) between the shaft (2) and the turbine wheel (5), wherein
• an end face (3) of the shaft (2) is provided with a protrusion (4), which comprises an outside diameter (A4) which is smaller than the outside diameter (A2) of the shaft (2),
• the turbine wheel (5) has a hollow receiving portion (7), which is formed integrally on the wheel rear side (6) thereof and the inside diameter (I7) of which corresponds to the outside diameter (A4) of the protrusion (4) and the outside diameter (A7) of which corresponds to the outside diameter (A2) of the shaft (2), wherein the protrusion (4) engages into the receiving portion (7), and
• the heat throttle (8) is formed by a cavity (8A, 8B), which has an inside diameter (I8) which is smaller than the outside diameter (A4) of the protrusion (4) and which extends from the protrusion (4) into the receiving portion (7).