The invention discloses a motor rotor which comprises a rotor core, an inverted trapezoidal
copper conducting bar, an outer aluminum conducting bar and an inner aluminum conducting bar. The structure of the motor rotor is characterized in that the rotor core is formed by laminating rotor
punching sheets; an outer groove, a middle groove and an inner groove are annually distributed on the outer side of the circumference of the rotor
punching sheet; the rotor
punching sheets are stacked together to form an outer conducting bar hole, a middle conducting bar hole and an inner conducting bar hole in the rotor core; the inverted trapezoidal
copper conducting bar is inserted into the middle conducting bar hole, the outer aluminum conducting bar is casted in the outer conducting bar hole, the inner aluminum conducting bar is casted in the inner conducting bar hole, aluminum end rings are casted on both ends of the rotor core and are provided with aluminum fan blades and aluminum balance columns; the outer aluminum conducting bar, the inner aluminum conducting bar, the aluminum end rings, the aluminum fan blades and the aluminum balance columns are integrally formed and are manufactured via a cast process. The motor rotor is higher in
motor efficiency than a cast-aluminum structured rotor, improves
copper bar shake and a sealing-
off phenomenon compared with an inserted-copper-bar structure, is simpler in process and lower in cost than a cast-copper structure rotor, and has excellent locked-rotor performance of cast-aluminum rotors and double-cage rotors.