Automatic connecting device for train main blast pipe

The invention discloses a train main blast pipe automatic connecting device which comprises a pipe body, a switch assembly, a connecting assembly and a positioning assembly, the switch assembly is installed at the end of the pipe body, the connecting assembly is arranged outside the pipe body, and the positioning assembly is arranged on the pipe body; the connecting assembly comprises a connecting body, an elastic piece and a fixing assembly for fixing the air pipe. The connecting body is connected to the periphery of the pipe body in a sliding mode and axially connected through an elastic piece, the fixing assembly is arranged on the connecting body, and the fixing assembly locks the connecting body under the action of pressure; the switch assembly comprises a fixing ring, a switch spring and a switch piece, the fixing ring is fixed in the pipe body, the switch piece is connected to the fixing ring through the switch spring, and the switch piece extends out of the pipe body; a plurality of vent grooves are f