Motor rotor cooling device and motor

The utility model discloses a heat dissipation device for a motor rotor. Rotating shaft, a first channel and a second channel are formed in the rotating shaft; the first channel is annularly arrangedoutside the second channel; the first channel and the second channel are concentrically arranged; the rotating shaft is divided into a heat collection end and a heat dissipation end, the heat collection end is provided with a ring part arranged in a radial mode along the outer edge of the rotating shaft, a third channel is formed in the ring part, and at least two pairs of first communication holes communicated with the third channel are formed in the heat collection end of the rotating shaft and used for enabling the third channel to be communicated with the first channel. According to the utility model, a unique heat radiation structure is employed, heat of the heating core area in the motor is conducted to the outside of the motor to carry out forced convection heat exchange with air, the heat exchange efficien