Replaceable new energy motor transmission shaft

The utility model discloses and provides a replaceable new energy motor transmission shaft, which comprises a casing, a machine cover is arranged on the outer surface of the casing, a bearing seat is arranged in the inner wall of the machine cover, one end of the bearing seat is connected with a transmission shaft, one end of the transmission shaft is connected with a clamping pipe, an external pipe is inserted into an inner wall cavity of an expansion part, and the clamping pipe is connected with the external pipe. After the external pipe is inserted and extends into the connecting pipe, the rotor is rotated to enable the connecting pipe and the clamping piece to be connected together so as to carry out first fixed connection, at the moment, through the action of the spring, the limiting pin and the limiting hole in the outer surface of the clamping pipe are clamped so as to carry out secondary fixing, and then the fixing piece is rotated to enable the expansion piece to contract to fasten the external pipe