Core assembly moulding sand mould structure for gearbox shell castings and core assembly moulding method

The invention relates to a core assembly moulding sand mould structure for gearbox shell castings and a core assembly moulding method. The core assembly moulding sand mould structure for the gearbox shell castings comprises inner cavity sand cores, outer contour sand cores and a pouring system sand mould for core assembly moulding; The inner cavity sand cores and the outer contour sand cores are assembled to form mould cavities for the shell castings; the upper side of the upper end face of each shell casting is provided with multiple round feeders, and a plurality of chilling blocks are arranged in each outer contour sand core among the corresponding round feeders; supplement structures are arranged in each outer contour sand core corresponding to the sides of side bosses on the lower parts of the side walls of the corresponding shell casting, and an insulating layer is arranged on the outer side of each supplement structure; and ingates communicated with the mould cavities of the corresponding castings are arranged in the pouring system sand mould. According to the core assembly moulding sand mould structure disclosed by the invention, moulding and casting cost of the castings is reduced; the work load of subsequent machining of the castings is reduced; and the production efficiency is improved.