MANUFACTURING METHOD OF PISTON FOR INTERNAL COMBUSTION ENGINE, PISTON FOR INTERNAL COMBUSTION ENGINE AND MANUFACTURING APPARATUS FOR PISTON FOR INTERNAL COMBUSTION ENGINE

摘要

To provide a manufacturing method of a piston for an internal combustion engine which enables an anodically oxidized coating film to be easily formed inside a piston pin hole and at a piston boss part.SOLUTION: The manufacturing method of a piston for an internal combustion engine includes the steps of: preparing a piston base material which has a piston head, and a cylindrical skirt part having one closed end connected to the piston head and the other open end, wherein a pair of piston pin holes are formed in a side surface of the skirt part; and applying anodic oxidation processing to inner surfaces of the piston pin holes by introducing electrolytes into the piston pin holes from introduction flow passages connected to the piston pin holes, and causing the electrolytes to flow into the inside of the cylindrical skit part, and while causing the electrolytes to flow out from the other end part of the skirt part.SELECTED DRAWING: Figure 1