Laser welded piston assembly

摘要

An exemplary piston may include a piston body having radially inner and outer body mating surfaces. The piston may further include a cooling gallery ring cooperating with the piston body to form a continuous upper combustion bowl surface and a cooling gallery. The cooling gallery ring may have radially inner and outer ring mating surfaces abutted along their corresponding radially inner and outer body mating surfaces, such that the cooling gallery is substantially enclosed. The piston body and cooling gallery ring may be joined together along the radially inner and radially outer interface regions to form a generally one-piece piston assembly. The radially outer interface region may be elongated in a direction parallel to the piston axis, e.g., facilitating a laser welding joining process.

主权项

1. A method, comprising:
providing a steel piston body defining a piston axis, the piston body forming a lower surface of a cooling gallery, the body including radially inner and outer body mating surfaces; assembling a steel cooling gallery ring with the piston body such that the piston body and cooling gallery ring cooperate to form a continuous upper combustion bowl surface having a radially inner portion defined by the piston body and a radially outer portion defined by the cooling gallery ring, the cooling gallery ring including a radially inner ring mating surface and a radially outer ring mating surface, wherein all mating surfaces between the piston body and the cooling gallery ring are aligned non-perpendicular to the piston axis; joining the body to the cooling gallery ring along a radially inner interface region, the radially inner interface region including the corresponding radially inner mating surfaces of the body and the cooling gallery ring; joining the body to the cooling gallery ring along a radially outer interface region, the radially outer interface region including the radially outer mating surfaces of the body and cooling gallery ring, wherein the radially outer interface region is elongated in a direction parallel to the piston axis; and establishing at least one of joining the body to the cooling gallery ring along a radially inner interface region and joining the body to the cooling gallery ring along the radially outer interface region as including laser welding, wherein the laser welding includes directing a laser along a path, the path extending along one of the body mating surfaces and one of the ring mating surfaces, the path oriented in a direction extending through an interior of the cooling gallery, wherein the laser welding includes:
running the laser at a first laser power, and thenrunning the laser at a second laser power less than the first power; wherein the ring is interference fit to the body along the radially outer interface region including the radially outer mating surfaces of the body and cooling gallery ring.