Patent ID: 9662707
Date: 2017-05-30
CPC Classifications: B22C,B22D

Claim:
1. A piston casting method for casting a piston comprising a columnar ring land part having a top wall, a pair of skirt parts extending downward from opposite end parts, in a diameter direction, of the ring land part, a pair of side wall parts extending from a lower face of the ring land part and linking opposite ends of the two skirt parts to each other, and a pair of pin boss parts formed on these side wall parts, a pair of cutout recess parts being provided in the lower face of the ring land part, an outside face of the side wall part facing the cutout recess parts, and an inside face in a radially outward direction of the cutout recess part being inclined in a direction away from a central axis of the piston in going downward, wherein the method comprises preparing a pair of main molds forming an outer peripheral face of the piston and a pair of side cores forming the pair of cutout recess parts, setting the main mold and the side core so as to form a cavity corresponding to the piston, charging the cavity with molten metal, and when the side core is moved downward and in a direction in which the side core is moved away from the central axis of the piston so as to carry out mold release from the cutout recess part after the piston within the cavity has solidified, tilting the side core in a direction in which an upper end of the side core approaches the central axis of the piston.