Rotor of an electric machine

A rotor of an electric machine, having a rotor body (3) which is rotatable about a rotor axis (2) and which comprises at least one rotor sub-body (4), and has in each case one or a plurality of cooling ducts (5) which at ends thereof have in each case one cooling duct opening (8.1, 8.2), wherein the one cooling duct opening (8.1) of one of the cooling ducts (5) is in each case disposed so as to be radially farther outside than the other cooling duct opening (8.2) of the same cooling duct (5) in such a manner that an airflow is established in the cooling duct (5) by virtue of centrifugal forces in the rotation of the rotor (1), wherein on one of two end sides of the rotor body (3) a first cover element (10) which covers a radially innermost partial cross section of at least one of the cooling duct openings (8.1) of at least one of the cooling ducts (5) is provided, characterized in that

• the first cover element (10) covers the radially innermost partial cross section of the respective cooling duct opening (8.1) by way of a peripheral portion which in terms of the rotor axis (2) is a radially outer peripheral portion (11), and in each case leaves a radially outermost partial cross section of the same cooling duct opening (8.1) uncovered as a cooling duct exit (8.1);
• in that
• the other cooling duct opening (8.2) of the same cooling duct (5) is in each case a cooling duct entrance, and in that one inflow which in terms of the rotor axis (2) is an axial inflow is in each case provided upstream of the cooling duct entrances (8.2);
• and in that
• the geometric center (S1) of the cooling duct exit (8.1) in terms of the rotor axis (2) is in each case offset in the radial direction in relation to the geometric center (S2) of the cooling duct entrance (8.2) of the same cooling duct (5).