Automatic separating type gearbox

The invention relates to an automatic separating type gearbox comprising a gearbox body, a gearbox cover, a motor device and a transmission assembly. The transmission assembly is mounted on the gearbox body, the automatic separating type gearbox further comprises an automatic separating mechanism, and the automatic separating mechanism comprises a metal block, a stop piece and a clamp piece. A metal block is connected to an output wheel and is circular, one face of the metal block is connected with the output wheel, and the other face of the metal block is connected with the stop piece. A notch is formed in the metal block, and the clamp piece is mounted at the notch. The gearbox cover is provided with a transmission piece corresponding to the output wheel, and a limiting ring is arrangedon the transmission piece and forms a limiting clamp groove. The periphery of the metal block is sleeved with the limiting ring, and the limiting clamp groove is matched with the clamp piece. The limiting ring, the stop piece