| 摘要 |
<p>A piston ring (5) inserted in a groove in an internal combustion engine piston (3) comprises at least two materially joined piston-ring discs (6, 7) arranged axially in series. In addition, this piston ring (5) can be compressed with a uniform axial intensity over its entire circumference in a partial, outer radial region. This compressibility is provided by the presence of at least one radially encircling, outwardly open annular gap (13) at the level of the plane in which the piston-ring discs (6, 7) are joined. At low pressure in the cylinder, this gap takes up lubricating oil. When the piston ring (5) is subjected to the gas pressure acting in the combustion chamber of the internal combustion engine, this lubricating oil is forced out of the annular gap (13) into the space (25) between the sliding surface (26) of the piston ring and the sliding surface (2) of the cylinder due to an axial constriction of the annular gap resulting from the said gas pressure. The piston rings (5) thus have a self-lubricating action controlled as a function of the gas pressure in the cylinder, thereby reducing wear both on the piston rings (5) themselves and on the sliding surfaces (2) of the cylinder. <IMAGE></p> |
