Sand casting die for casting of lower connecting plate

The invention belongs to the technical field of machine manufacturing, in particular to a sand casting die for casting of a lower connecting plate. The sand casting die is high in production efficiency and simple in process, and comprises at least two mutually overlaid die cavity plates and N cores, wherein N is an even number; the die cavity plates are transversely arranged; a female die cavity is arranged on the left end surface of each die cavity plate, and a male die cavity is arranged on the right end surface of the die cavity plate; the male die cavity is matched with the female die cavity of the adjacent die cavity plate; two symmetrically arranged cylinders and two symmetrically arranged lug bosses are arranged in each male die cavity; two grooves I opening outwards and communicated with the male die cavity are formed in the side wall of the male die cavity; two grooves II opening outwards and communicated with the female die cavity are formed in the side wall of the female die cavity; the grooves I are respectively formed between the cylinders and the lug bosses; the grooves I are matched with the grooves II of the adjacent die cavity plate; one ends of the cores are arranged in the grooves I, and bulges are arranged at the other end of the cores; the end surfaces of the bulges are higher than the side surfaces of the lug bosses, and are propped against the side wall of the female die cavity of the adjacent die cavity plate.