The utility model provides a self-
locking differential assembly which comprises a shell, a planetary gear
assembly, a side gear, a first main gear and a planetary gear carrier, the planetary gear
assembly comprises a planetary gear and a rotating shaft, a semi-closed frame is arranged on the outer side of the planetary gear carrier, the frame is fixedly connected with the planetary gear carrier, a
locking mechanism is arranged on the outer side of the frame, and the side gear is fixedly connected with the side gear. The
locking mechanism comprises a shell, a motor is arranged at the end, away from the frame, of the shell, an output shaft of the motor is connected with a lead screw, a locking block assembly is arranged in the shell and comprises a connecting block and a plurality of sliding blocks, the sliding blocks are slidably connected with the shell, the connecting block is in threaded connection with the lead screw, and locking grooves matched with the sliding blocks are formed in the ends, close to the sliding blocks, of rotating shafts. The locking block assembly is inserted into the rotating shaft through the locking groove. According to the self-
locking differential mechanism assembly, the frame is installed on the planetary gear carrier, the
locking mechanism is installed on the frame, the locking block assembly is connected with the rotating shaft in an inserted mode, axial
spinning of the planetary gear assembly is locked, and therefore the self-locking function of the differential mechanism is achieved.