Patent ID: 7311075

Claim:
Multi-part piston ( 1 ) for an internal combustion engine having an upper part ( 2 ) that has a piston crown ( 4 ), on which part a ring wall ( 6 ) having a ring belt ( 8 ) is molded on, and having a lower part ( 3 ) that is connected with the upper part ( 2 ) by way of a screw connection ( 12 , 24 - 31 ) and has pin bosses ( 17 , 17 ′) having pin bores ( 18 , 18 ′) on its lower side facing away from the upper part ( 2 ), and having piston skirt elements ( 21 ) connected with the pin bosses ( 17 , 17 ′), wherein the screw connection consists of the following elements: of an essentially tubeshaped connection projection ( 24 ) that is affixed on the underside of the piston crown ( 4 ) and is disposed coaxial to the piston longitudinal axis ( 20 ), and has an outside thread ( 25 ) on its end that faces away from the piston crown ( 4 ) in the axial direction, said thread being disposed on a circumferential side of the connection projection ( 24 ) that lies radially on the outside of the connection projection, of a support rib ( 12 ), said support rib being molded onto the lower part ( 3 ), said rib having an inside thread ( 26 ) on its piston crown end, viewed in the axial direction, said thread being disposed on a surface that lies radially on the inside of said rib, and of an essentially tube-shaped intermediate sleeve ( 27 ) having a thread ( 28 ) that lies on the inside and a thread ( 29 ) that lies on the outside, by means of which the upper part ( 2 ) can be screwed together with the lower part ( 3 ), by way of the connection projection ( 24 ), and by way of the support rib ( 12 ), and which sleeve is configured in such a manner that when this happens, the connection projection ( 24 ) can be expanded and the intermediate sleeve ( 27 ) can be compressed.