Closing of holes in cast pistons resulting from the manufacturing process

摘要

In a cast iron piston (1) with annular cooling duct (6) in the area behind the ring grooves (5), this cooling duct (6) is formed, in the manufacture of the piston (1) by a casting process, by the provision of a removable core corresponding to the shape of the cooling duct in the casting mould. In order to support the core in the casting mould, the said core is provided with cylindrical support feet which, in the piston, cause bores (8) opening into the cooling duct. In order to close these bores (8) created in the manufacturing process, some of which, at least, are not necessary, a slotted light clamp collar (9) in accordance with DIN 7346 is used which, easily inserted, bears on the inner wall (10) of the cooling duct (6) with a positive interlock. A spiral pin in accordance with DIN 7343 can also be used in place of the light clamp collar. <IMAGE>