FORMING METHOD OF INSERTION HOLE FOR PISTON PIN

摘要

A method of shaping the gudgeon pin bores formed in gudgeon pin bosses of pistons comprises introducing into the bores portions of a pin-shaped tool before the insertion of the gudgeon pin. A load is applied to the pin-shaped tool and the direction of the load and the shape of the pin-shaped tool are chosen so that areas of bore-defining walls of the bosses subjected to high stresses by the gudgeon pin in use, and therefore liable to crack, are radially outwardly deformed to reduce the incidence of cracks.