Provided is a sliding member having a hard carbon coating that makes high wear resistance compatible with a low coefficient of friction and that has excellent peeling resistance. A sliding member (100) includes a base member (10) and a hard carbon coating (12) formed on the base member (10). The indentation hardness of the hard carbon coating (12) decreases gradually from the base member side to the surface side. The hard carbon coating (12) has an indentation hardness distribution at 0T/Ttotal0.6 approximated by a first line and an indentation hardness distribution at 0.9T/Ttotal1 approximated by a second line, and the intersection between the first line and the second line (T2/Ttotal, H2) satisfies Expression (1), (H3H1)T2/Ttotal+H1<H20.9H1, and Expression (2), 0.6T2/Ttotal0.9.

Provided is a sliding member having a hard carbon coating that makes high wear resistance compatible with a low coefficient of friction and that has excellent peeling resistance. A sliding member (100) includes a base member (10) and a hard carbon coating (12) formed on the base member (10). The indentation hardness of the hard carbon coating (12) decreases gradually from the base member side to the surface side. The hard carbon coating (12) has an indentation hardness distribution at 0T/Ttotal0.6 approximated by a first line and an indentation hardness distribution at 0.9T/Ttotal1 approximated by a second line, and the intersection between the first line and the second line (T2/Ttotal, H2) satisfies Expression (1), (H3H1)T2/Ttotal+H1<H20.9H1, and Expression (2), 0.6T2/Ttotal0.9.

Under a state in which the combination oil ring is mounted in an oil ring groove before inserted into a cylinder bore, when an inclined surface of an upper ear portion of an expander spacer is held in contact with an inner peripheral surface of an upper segment and an inclined surface of a lower ear portion of the expander spacer is held in contact with an inner peripheral surface of a lower segment, an upper protrusion amount (P1) from an outer peripheral-side end surface of the expander spacer to an outer peripheral surface vertex of the upper segment is larger than a lower protrusion amount (P2) from the outer peripheral-side end surface of the expander spacer to an outer peripheral surface vertex of the lower segment. When the combination oil ring is inserted into the cylinder bore, the sealing performance can be improved to reduce the oil consumption.

Provided is a combined oil ring that can provide reduction in oil consumption of the engine oil without degrading the oil sealing performance between the lower surface of the side rail and the lower surface of the oil ring groove even when the tension of the combined oil ring is reduced. The combined oil ring includes: a pair of upper and lower side rails fitted in an oil ring groove of a piston, the side rails each being formed in a planar and annular shape and having a sliding contact portion in sliding contact with a cylinder; and a spacer expander disposed between the pair of upper and lower side rails and having a seating tab portion, the seating tab portion including an upper seating tab portion and a lower seating tab portion for pressing the side rails outward, wherein, each in the pair of upper and lower side rails has, in a sectional shape of the sliding contact portion taken along an axial direction of the piston, an outermost diameter portion located below a center of an axial direction width of the side rail, and the combined oil ring includes an anti-tilt device at positions where the upper seating tab and the lower seating tab portion come into contact with inner peripheral sides of the side rails.

Provided is a combined oil ring that can provide reduction in oil consumption of the engine oil without degrading the oil sealing performance between the lower surface of the side rail and the lower surface of the oil ring groove even when the tension of the combined oil ring is reduced. The combined oil ring includes: a pair of upper and lower side rails fitted in an oil ring groove of a piston, the side rails each being formed in a planar and annular shape and having a sliding contact portion in sliding contact with a cylinder; and a spacer expander disposed between the pair of upper and lower side rails and having a seating tab portion, the seating tab portion including an upper seating tab portion and a lower seating tab portion for pressing the side rails outward, wherein, each in the pair of upper and lower side rails has, in a sectional shape of the sliding contact portion taken along an axial direction of the piston, an outermost diameter portion located below a center of an axial direction width of the side rail, and the combined oil ring includes an anti-tilt device at positions where the upper seating tab and the lower seating tab portion come into contact with inner peripheral sides of the side rails.

An engine includes a housing and a combustion assembly. The combustion assembly includes an annular bore and a combustion piston assembly disposed within the annular bore. The combustion piston assembly includes a set of pistons, a first sealing ring connected to each piston and a second sealing ring connected to each piston. The second sealing ring is configured to provide selective access between the annular bore and at least one fluid conduit carried by the engine. The engine includes at least one valve configured to move between a first position within the annular bore to allow the combustion piston assembly to travel within the annular bore from a first location proximate to the at least one valve to a second location distal to the at least one valve and a second position within the annular bore to define a combustion chamber.

An engine includes a housing and a combustion assembly. The combustion assembly includes an annular bore and a combustion piston assembly disposed within the annular bore. The combustion piston assembly includes a set of pistons, a first sealing ring connected to each piston and a second sealing ring connected to each piston. The second sealing ring is configured to provide selective access between the annular bore and at least one fluid conduit carried by the engine. The engine includes at least one valve configured to move between a first position within the annular bore to allow the combustion piston assembly to travel within the annular bore from a first location proximate to the at least one valve to a second location distal to the at least one valve and a second position within the annular bore to define a combustion chamber.

To provide a combined oil control ring for an automobile engine which is capable of maintaining an outstanding oil control function without causing the occurrence of firm sticking between the spacer expander and the side rails even when the engine is operated over an extended period of time, the crest and the trough of the spacer expander are each provided with a seating tab for pressing an inner peripheral surface of the side rail, a projection for supporting the side rail, and a middle part between the seating tab and the projection, and a ratio (S.sub.min/S.sub.0) is 1.9% or greater, where S.sub.min is a minimum axial cross-sectional area of a space formed between the middle part and the side face of the side rail opposed thereto, and S.sub.0 is an axial cross-sectional area from a groove bottom of an oil ring groove of a piston, to which the combined oil control ring is attached, to an inner wall of a cylinder liner.

The present disclosure provides a sealing ring assembly with one or more piston-integrated gap cover features, configured to seal a high-pressure region from a relatively lower pressure region of a piston and cylinder device. The sealing ring assembly may include two rings which each may include one or more ring segments. The one or more gap-cover features, which may be in the form of protrusions in the piston ring groove, may engage with corresponding flat sections of the ring segments. As the sealing ring wears, the gap-cover features may stay engaged with the ring segments, thereby maintaining a seal.

The present disclosure provides a sealing ring assembly with one or more piston-integrated gap cover features, configured to seal a high-pressure region from a relatively lower pressure region of a piston and cylinder device. The sealing ring assembly may include two rings which each may include one or more ring segments. The one or more gap-cover features, which may be in the form of protrusions in the piston ring groove, may engage with corresponding flat sections of the ring segments. As the sealing ring wears, the gap-cover features may stay engaged with the ring segments, thereby maintaining a seal.