A sliding member includes a base material, and an amorphous hard carbon film formed on a surface of the base material, in which a sp.sup.2 ratio of the amorphous hard carbon film increases from an inner surface side corresponding to the base material side toward an outer surface side thereof to become a maximum value and further decreases toward the outer surface side.

A sliding member includes a base material and an amorphous hard carbon film formed on a surface of the base material, and the amorphous hard carbon film has a graded structure in which a sp.sup.2 ratio increases from an inner surface side corresponding to the base material side toward an outer surface side. A piston ring includes the sliding member.

A sliding member having a hard carbon coating that has a thickness of 3 m or more and demonstrates high peeling resistance and high wear resistance is provided. A sliding member 100 according to the present disclosure includes a base member 10 and a hard carbon coating 12 that is formed on the base member 10 and has the hydrogen content of 3 atomic % or less and a thickness of 3 m or more. When HM represents a Martens hardness of the hard carbon coating 12 and HIT represents an indentation hardness, the ratio HM/HIT is 0.40 or more.

A supporting arrangement for an eccentric member (8) of an adjusting arrangement (6) of a connecting rod (2) of a reciprocating piston internal combustion engine having at least one piston rod (18) that is guided displaceably by a piston (20) and a seal member (24) is connected to the supporting piston (20) in a supporting cylinder (12, 14) which is provided in the connecting rod (2) and has a longitudinal axis (16). The supporting piston (20) enclosing at least one cylinder chamber (22) with the supporting cylinder (12, 14). A side (28) of the supporting piston (20) that is directed toward the cylinder chamber (22) has a brake piston (30) that can be moved in the longitudinal axis (16). The brake piston (30) is mounted on the supporting piston (20) and can be prestressed by a spring (32).

A supporting arrangement for an eccentric member (8) of an adjusting arrangement (6) of a connecting rod (2) of a reciprocating piston internal combustion engine having at least one piston rod (18) that is guided displaceably by a piston (20) and a seal member (24) is connected to the supporting piston (20) in a supporting cylinder (12, 14) which is provided in the connecting rod (2) and has a longitudinal axis (16). The supporting piston (20) enclosing at least one cylinder chamber (22) with the supporting cylinder (12, 14). A side (28) of the supporting piston (20) that is directed toward the cylinder chamber (22) has a brake piston (30) that can be moved in the longitudinal axis (16). The brake piston (30) is mounted on the supporting piston (20) and can be prestressed by a spring (32).

Provided is a side rail 1 having an outer peripheral surface 14, an inner peripheral surface 13, a first axial side surface 11, and a second axial side surface 12 parallel to the first axial side surface 11, in which, a beveled portion 30 is provided between the outer peripheral surface 14 and the second axial side surface 12, the beveled portion 30 is formed in a tapered surface having a diameter gradually decreasing from the first axial side surface 11 toward the second axial side surface in an axial direction; a tapered surface 30a is provided between a first tapered surface portion 30a1 with an angle of 10 or more to the axial direction and a second tapered surface portion 30a2 provided between the first tapered surface portion 30a1 and the outer peripheral surface 14 and having a smaller angle of inclination to the axial direction than that of the first tapered surface portion.

Provided is a combined oil ring that further reduces engine oil consumption. A combined oil ring attached to an oil ring groove of a piston includes: a pair of upper and lower side rails each formed into a flat annular shape, and having a slide contact part that comes into sliding contact with a cylinder; and a spacer expander arranged between the pair of upper and lower side rails. In at least the upper side rail of the pair of upper and lower side rails, a cross-sectional shape of the slide contact part along an axial direction of the piston is a tapered shape linearly spreading from upper to lower parts of the piston; the tapered shape is at an angle of 5 to 30 degrees with respect to a central axis of the spacer expander, and has a vertex of the tapered shape within 0.15 mm from a lower end of the side rail; and a part closer to the lower end than the vertex is formed into a curved shape having a curvature of R0.01 to 0.5.

Provided is a combined oil ring that further reduces engine oil consumption. A combined oil ring attached to an oil ring groove of a piston includes: a pair of upper and lower side rails each formed into a flat annular shape, and having a slide contact part that comes into sliding contact with a cylinder; and a spacer expander arranged between the pair of upper and lower side rails. In at least the upper side rail of the pair of upper and lower side rails, a cross-sectional shape of the slide contact part along an axial direction of the piston is a tapered shape linearly spreading from upper to lower parts of the piston; the tapered shape is at an angle of 5 to 30 degrees with respect to a central axis of the spacer expander, and has a vertex of the tapered shape within 0.15 mm from a lower end of the side rail; and a part closer to the lower end than the vertex is formed into a curved shape having a curvature of R0.01 to 0.5.

Provided is a piston ring for an internal combustion engine that enables size reduction of a chamfered edge without leading to the chipping, and sufficient size reduction of a flow passage of a blow-by gas in a piston ring gap, thus effectively restraining the blow-by gas from passing through the piston ring gap. A piston ring 1 with a piston ring gap 2 used for an internal combustion engine includes a chamfered edge 3 continuous to at least one of piston ring end faces at the piston ring gap 2 and an outer peripheral surface 1a of the piston ring 1. The chamfered edge 3 has a curved shape.

Provided is a piston ring for an internal combustion engine that enables size reduction of a chamfered edge without leading to the chipping, and sufficient size reduction of a flow passage of a blow-by gas in a piston ring gap, thus effectively restraining the blow-by gas from passing through the piston ring gap. A piston ring 1 with a piston ring gap 2 used for an internal combustion engine includes a chamfered edge 3 continuous to at least one of piston ring end faces at the piston ring gap 2 and an outer peripheral surface 1a of the piston ring 1. The chamfered edge 3 has a curved shape.