Piston for an internal combustion engine

Abstract

A piston for an internal combustion engine is formed by the following steps: (a) providing a blank of a piston base body, having an outer joining surface, an inner joining surface and a circumferential lower cooling channel part that runs between the two joining surfaces, (b) providing a blank of a piston ring element, having an outer joining surface, an inner joining surface and a circumferential upper cooling channel part that runs between the two joining surfaces, (c) forming a circumferential widened region on at least one joining surface, the widened region extending toward the related cooling channel part, (d) connecting the blank of the piston base body with the blank of the piston ring element by way of their joining surfaces, by friction welding, to produce a piston blank, and (e) machining the piston blank further and/or finish-machining it to produce a piston.

What is claimed is: 
     
         1 . A piston for an internal combustion engine, comprising:
 a piston base body having at least a piston skirt;   a piston ring element having at least a piston crown, a circumferential top land, and a circumferential ring belt provided with ring grooves,   wherein the piston base body and the piston ring element form a circumferential, closed cooling channel, wherein the piston base body and piston ring element are connected with one another by friction welding, and wherein the cooling channel is essentially free of friction-welding beads.   
     
     
         2 . The piston according to  claim 1 , wherein the piston ring element has a combustion chamber bowl. 
     
     
         3 . The piston according to  claim 1 , wherein the piston ring element has at least one wall region of a combustion chamber bowl, and wherein the piston base body has at least one crown region of a combustion chamber bowl.