Patent ID: 8651084

Claim:
A two-part piston for an internal combustion engine, comprising: an upper part forming a piston crown, and having a dead-end hole bore with inside thread, the bore lying coaxial to a piston axis and being disposed on an underside of the upper part facing away from the piston crown, and a lower part, on an underside of which pin bosses with pin bores and skirt elements that connect the pin bosses with one another are disposed, the lower part having an upper crown part with an opening that lies coaxial to the piston axis, by way of which the upper part is connected with the lower part by means of a hexagonal screw, wherein a radial inside of the opening has a ring-shaped surface disposed on the skirt side, wherein a head of the hexagonal screw has a contact surface on the piston crown side, wherein a tube-shaped intermediate piece with an upper face surface is disposed on the contact surface such that the face surface lies closer to the piston crown than the ring-shaped surface, and wherein an expansion sleeve is disposed between the face surface of the intermediate piece and the ring shaped surface, said sleeve having a collar directed radially inward on its side facing the piston crown, said collar having a radially oriented inside surface disposed on its side facing away from the piston crown, which surface rests on the face surface, and said sleeve having a contact surface that faces the piston crown in a lowermost region of the sleeve, which surface rests against the ring-shaped surface.