Bi-metallic piston ring carrier
AssigneeMahle International GmbH
InventorsThomas J. Smith, Likhit Sethi
Life of this patent
Estimating the term…
Abstract
A ring carrier for a piston for an internal combustion engine is formed by a carrier body having an outer circumferential surface, an inner circumferential surface, a top surface and a bottom surface, with at least one ring groove formed in the outer circumferential surface. An outer circumferential portion of the ring carrier is formed of gray iron, and an inner circumferential portion is formed of ductile iron. A transition region between the outer circumferential portion and the inner circumferential portion intersects upper and lower flanks of the ring groove, so that an outer circumferential extent of the flanks is formed of gray iron and an inner circumferential extent of the flanks is formed of ductile iron.
Claims10
A ring carrier for an piston for an internal combustion engine, comprising a carrier body having an outer circumferential surface, an inner circumferential surface, a top surface and a bottom surface, with at least one ring groove formed in the outer circumferential surface, the at least one ring groove having upper and lower flanks, wherein an outer circumferential portion of the ring carrier is formed of gray iron, and an inner circumferential portion is formed of ductile iron.
A method for forming a ring carrier for a piston for an internal combustion engine, comprising casting a ring carrier body using a centrifugal casting method, the ring carrier body having an inner circumference and an outer circumference, wherein in a first casting step molten gray iron is added to a casting mold, and in a second casting step, molten gray iron doped with magnesium is added to the casting mold, so that the finished ring carrier has an outer circumferential portion formed of gray iron, and an inner circumferential portion formed of ductile iron, and cutting at least one ring groove in the outer circumference so that a transition region between the outer circumferential portion and the inner circumferential portion intersects flanks the ring groove.
A method for forming a piston for an internal combustion engine, comprising:
- casting a ring carrier body using a centrifugal casting method, wherein in a first casting step molten gray iron is added to a centrifugal casting mold, and in a second casting step, molten gray iron doped with magnesium is added to the casting mold, so that the cast ring carrier has an outer circumferential portion formed of gray iron, and an inner circumferential portion formed of ductile iron,
- casting an aluminum piston body around the ring carrier in a casting process;
- and
- finishing the piston by cutting at least one ring groove in the ring carrier, so that a transition region between the outer circumferential portion and the inner circumferential portion intersects flanks of the at least one ring groove.
Dependencies are inferred from the claim text.