Abstract: A multipart cooled piston for a combustion engine has a piston upper part of steel comprising a combustion bowl and a ring wall with ring belt, and a piston lower part comprising a piston skirt, pin bosses for receiving the piston pin connecting the piston to the connecting rod, and pin boss supports connected to the piston skirt. An inexpensive manufacture and high form stability are achieved in that a cooling channel formed in the piston upper part has holes towards the piston crown spread over its circumference, with the piston material present between such holes forming supporting ribs that each form sections of an all-round ring rib radially to the longitudinal piston axis (K), The piston lower part has an annular and all-round carrier rib with a connection surface connected to the pin boss supports.

Abstract: A single-part cooling channel piston for a combustion engine with a piston head of forged steel comprises a combustion bowl in the piston crown, a ring wall with ring belt and an all-round closed cooling channel level with the ring belt. The piston skirt is connected to the pin bosses attached to the piston head. Inexpensive manufacture together with improved cooling and good form stability of the piston is achieved by providing the cooling channel with holes spread over its circumference towards the piston crown and spaced such that the piston material present between such holes forms supporting ribs for the piston crown.