JPS56117861A - Casting method of hollow cam shaft - Google Patents

Abstract

PURPOSE:To prevent a core from bending during pouring and simultaneously casting a core print together with an oil hole and core print holes that can be utilized as oil feed holes in the shaft core part by putting the barlike core having molded with core print parts in one piece beforehand into a cavity, supporting the core shaft part by the core print parts, and pouring molten metal then removing the core. CONSTITUTION:A required number of core prints 5 for the time of firing in a shell heating metal mold are beforehand formed to a barlike core 4 of a small diameter into one piece. Thence, this core 4 is set into the mold cavity. At this time, the barlike parts 4', 4' are grasped by the mold and the ends of the respective core prints 5 are inserted into the holes etc. provided in the mold or are grasped with the mold so that the core 4 is kept held to the shaft core part by means of the core prints 5. Next, molten metal is poured into the cavity and the core 4 is heated. At this time, the pouring pressure is applied but the bending of the core 5 is prevented by the supporting effect of the core prints 5 and the core 4 is inserted with good accuracy into the shaft center part of a cam shaft 1 to be cast. Next, the core sand is removed by such a method as applying vibrations after disassembling the flask, whereby an oil hole 7 and the core print holes that can be utilized as oil feed ports are formed simultaneously to the shaft core part of the shaft 1.