Joined connection on a two-piece steel piston and joining method

Abstract

A piston, in particular, a gallery-cooled piston for an internal combustion engine has a piston bottom part and a piston upper part which are connected in a joining process to produce the piston. The piston upper part has at least one ring zone and an inner wall. The piston bottom part has a radially circumferential oblique surface at the end which faces the piston upper part. The oblique surface, interacting with the inner wall of the piston upper part, brings about a centering action during the joining process of the piston parts. A joining method for manufacturing a piston is also disclosed.

What is claimed: 
     
         1 . A piston for an internal combustion engine, having a piston lower part and a piston upper part that are connected in a joining process to form the piston, wherein the piston upper part having at least one ring belt and an inner wall, comprising the piston lower part having a radially circumferential oblique surface at an end facing the piston upper part that interacts with an inner wall of the piston upper part to bring about a centering effect during the joining process of the piston upper and lower parts. 
     
     
         2 . The piston from  claim 1 , wherein the piston lower part has at least one sliding surface that interacts with the inner wall of the piston upper part in the joining process. 
     
     
         3 . The piston from  claim 1 , wherein at least contact surface is provided in the area of at least one joining seam to form a gap. 
     
     
         4 . The piston from  claim 3 , wherein the gap adjacent the contact surface acts to hold soldering material. 
     
     
         5 . The piston from  claim 1 , wherein a repository is provided to receive soldering material. 
     
     
         6 . The piston from  claim 1 , wherein a circumferential collar is provided on the piston upper part as a limit during the joining process interacting with a stop. 
     
     
         7 . The piston from  claim 6 , wherein the collar is removed after completion of the joining procedure. 
     
     
         8 . The piston from  claim 1 , wherein the piston upper part forms at least one ring belt after the joining procedure. 
     
     
         9 . A method for producing a piston, for an internal combustion engine, having a piston lower part and a piston upper part that are connected in a joining process to form the piston, wherein the piston upper part has at least one ring belt and an inner wall, the method comprising:
 preparing the piston upper part and the piston lower part; and   joining the piston parts, characterized in that wherein, during the joining process, centering of the piston upper part to the piston lower part takes place.   
     
     
         10 . The method from  claim 9 , comprising:
 removing at least one stop for the joining procedure in at least one additional procedural step.