Motor casing air passage casting sand core

The invention relates to the field of motor manufacturing, in particular to a motor shell air passage casting sand core which comprises an annular upper core body and an annular lower core body which are used for forming end air passages, a plurality of forming pieces used for forming middle air passages are detachably connected between the upper core body and the lower core body, and the forming pieces are arranged in the circumferential direction. The upper core body and the lower core body are respectively provided with an inserting groove used for being matched with the end of the forming piece in an inserting mode, the positions, opposite to the inserting grooves, of the upper core body and the lower core body are bonded with the forming piece, and glue injection holes communicated with the corresponding inserting grooves are formed in the outer side walls of the upper core body and the lower core body towards the interiors of the upper core body and the lower core body. The sand core is arranged in a sp