| CPC F16J 9/203 (2013.01) [F16J 9/26 (2013.01)] | 5 Claims |
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1. A piston ring for an internal combustion engine formed so as to have a tapered shape by a peripheral surface that gradually projects outward from a top to a bottom, and an axial cross-sectional shape of a Napier ring,
the peripheral surface being constituted by
an outer edge end portion that has a non-tapered shape and comes into sliding contact, as a peripheral sliding surface, with a mating material,
an outer peripheral tapered part formed at a predetermined taper angle above the outer edge end portion,
a curved surface part having a diameter that gradually decreases inward from the outer edge end portion to a lower end in an axial direction, and
a lower end portion forming a section of the curved surface part,
a distance (d2) between a lower limit position of the outer edge end portion and a position of the lower end portion in a ring axial direction being within a range of 0.001 mm to 0.05 mm, and
a contact width (d1) of the outer edge end portion in the ring axial direction being within a range of 0.01 mm to 0.3 mm,
the distance (d3) between the position of the outer edge end portion and the position of the lower end portion in the ring radial direction is within a range of 0.015 mm to 0.050 mm, and
d2/d3 is within a range of 0.20 to 1.20, where d3 is a distance between a position of the outer edge end portion and a position of the lower end portion in a ring radial direction.
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