Abstract: A cooled piston head and method of manufacture, the piston head having a closed cooling chamber. In one embodiment, the piston head is formed of a top member, an intermediate member and a pin boss member joined to each other preferably by welding; the top and intermediate members are provided with circumferential grooves which defines the closed cooling chamber. In an alternate embodiment, the head is formed of a top member and a pin boss member joined together preferably by welding; the closed cooling chamber is defined by circumferential grooves provided on both members.

Abstract: A cooled piston head and method of manufacture, the piston head having a closed cooling chamber. In one embodiment, the piston head is formed of a top member, an intermediate member and a pin boss member joined to each other preferably by welding; the top and intermediate members are provided with circumferential grooves which defines the closed cooling chamber. In an alternate embodiment, the head is formed of a top member and a pin boss member joined together preferably by welding; the closed cooling chamber is defined by circumferential grooves provided on both members.

Abstract: A method for the manufacture of a piston head having a cooling chamber is disclosed. The two portions composing the piston head are made separately; the underside of the upper portion is provided with a circumferential peripheral groove; notches are provided on both sides of the open end of the circumferential peripheral groove; a circumferential annular plate is placed on the notches thereby closing the circumferential peripheral groove; the two portions making up the head are joined to each other by welding and cause the inner edge of the annular plate to be retained in the piston head and become an integral part thereof.

Abstract: Piston tops (1, 70), specially those provided with combustion chamber (2, 20) and ring zone (3, 30) have their cooling condition sensibly improved in such regions due to a better use of the cooling oil capacity by closing the cooling chamber (5, 50) and the region 2I under the combustion chamber by annular ring members (96, 13) in a resilient material, e.g., a polymeric material or, preferably a spring steel, which clamp under the cooling chamber (5, 50) and the region 2I with dimensional interference respectively with grooves (10, 100), notches (11, 110) and groove 15. Methods for the manufacture of such top portion having a reduced compression height are also described.

Abstract: A method for the manufacture of a two-piece piston wherein the top portion and the pin boss portion, which define the piston head, are fabricated separately by cold or hot forming, casting or sintering, and joined together by welding such as, for instance, friction welding. The top portion and the pin boss portion may be of the same material or different materials, and obtained by the same method or by different methods.