Rotor-cooling structure of a drive motor

A rotor-cooling structure of a drive motor including an inner shaft, a rotor shaft surrounding the inner shaft, a rotor connected to the rotor shaft, and a stator disposed to be spaced apart from the rotor, the rotor-cooling structure comprising:

• a first flow passage formed in the inner shaft;
• a second flow passage formed in the rotor shaft to receive oil through the first flow passage;
• a third flow passage formed in a plate disposed at an end of a rotor core, constituting the rotor, to be connected to the second flow passage;
• and
• a fourth flow passage formed to be connected to the third flow passage and to penetrate the rotor core in a direction in which core plates constituting the rotor core are stacked,
• wherein the third flow passage extends in a direction from the rotor shaft toward an outer circumference of the rotor core,
• wherein an uppermost portion of the rotor core that is adjacent to the plate contacts the oil flowing through the third flow passage,
• wherein the third flow passage is inclined in a direction opposite a rotating direction of the rotor at a predetermined angle with respect to a direction from a center of the inner shaft toward the outer surface of the rotor core,
• wherein the third flow passage and the fourth flow passage are provided in a plurality thereof, and the number of fourth flow passages is the same as the number of third flow passages, and
• wherein the fourth flow passages are spaced apart from permanent magnets provided in the rotor.