| 摘要 |
In a liquid-cooled, composite piston for internal-combustion engines, particularly for medium-speed diesel engines, comprising a lower part, which made of a material comprising an eutectic aluminum-silicon alloy which lower part is connected to an upper part comprised of a ferrous material, said upper part formed on its underside with a concentric top rib, which rib forces the opposite bearing surface of the lower part and is so arranged that the rib constitutes the radially inner boundary of an annular cooling channel, which is disposed in the upper part behind the top land of the piston and behind at least part of the ring-carrying portion of the piston said rib also defining a central cooling chamber, which is disposed in the upper part and which communicates with the cooling channel by radial coolant bores, the improvement comprising a ring comprised of a ferrous material concentrically disposed and gripped between the bearing surface of the bearing rib and the opposite bearing surface of the lower part of the piston in an arrangement in which the confronting bearing surfaces of the bearing rib and the gripped ring are in peripheral rolling contact with one another.
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