Patent ID: 7302927

Claim:
Two-part piston ( 1 ) for an internal combustion engine, having an upper part ( 2 ) that forms a piston crown ( 4 ), and on the underside of which, facing away from the piston crown ( 4 ), a cylindrical pin ( 31 ) having an outside thread ( 32 ), which lies coaxial to the piston axis ( 12 ), is disposed, having a lower part ( 3 ), on the underside of which pin bosses ( 9 , 9 ′) with pin bores ( 10 , 10 ′) and skirt elements ( 13 , 13 ′) that connect the pin bosses ( 9 , 9 ′) with one another are disposed, whereby the lower part ( 3 ) has an opening ( 27 ), on the piston crown side, that lies coaxial to the piston axis ( 12 ), in which the pin ( 31 ) is guided, and whereby the upper part ( 2 ) and the lower part ( 3 ) are connected with one another by means of a nut ( 29 ) that is screwed onto the outside thread ( 32 ) of the pin ( 31 ) wherein the lower part ( 3 ) has an elastically resilient upper base part ( 25 ) that delimits a closed, ring-shaped cooling channel ( 24 ) disposed coaxial to the piston axis ( 12 ), having oil in-flow and out-flow openings ( 34 , 35 ), on the skirt side, which channel is delimited by the upper part ( 2 ) on the piston crown side, whereby an expansion sleeve ( 26 ) disposed coaxial to the piston axis ( 12 ), directed upward, elastic in the axial direction, is formed onto the base part ( 25 ), radially on the inside, which forms the radially inner delimitation of the cooling channel ( 24 ), and which has the opening ( 27 ) on its piston-crown-side end, whereby the opening ( 27 ) is provided with a collar ( 28 ), which is directed radially inward, and that a compression sleeve ( 30 ) that lies coaxial to the piston axis ( 12 ) and is elastic in the axial direction is formed onto the nut ( 29 ), on the piston crown side, which rests against the collar ( 28 ) on the piston crown side.