A multi-piece oil scraper piston ring includes a slotted spring element and at least one lamella element which is operatively connected to the slotted spring element and provided with a joint, the spring element being designed as a meander spring that axially receives and radially supports the lamella element, the two end regions of the meander spring being provided with legs that extend approximately parallel to one another and the axial length of which is designed such that the legs at least partially engage in the joint of the lamella element.

A combination oil ring includes a pair of upper and lower side rails and a spacer expander arranged there between, the spacer expander including a plurality of upper pieces and lower pieces alternately arranged in a circumferential direction with the pieces axially and circumferentially apart from each other, a coupling piece coupling pieces adjacent to each other, and flange portions formed standing at inner circumferential-side end portions of the upper pieces and the lower pieces so as to press the side rails, and a through hole being formed in the flange portions, wherein side rail support portions that project axially are formed at portions in the circumferential direction of outer circumferential-side end portions of the upper pieces and the lower pieces.

In a combination oil ring, when a line passing through a center of a segment width is a first intermediate line, a length of a line segment between a position on an engine combustion chamber side and a position on a side distant from the engine combustion chamber on a contour curve at a position at a distance of 3 m from an outer peripheral vertex toward an inner peripheral side in a segment radial direction is L, and an intermediate line of the line segment L is a second intermediate line, the second intermediate line is located on the side more distant from the engine combustion chamber than the first intermediate line, and the outer periphery vertex of the segment is located on the second intermediate line or on the side more distant from the engine combustion chamber than the second intermediate line.

A combination oil ring includes a pair of upper and lower side rails and a spacer expander arranged therebetween, the spacer expander including a plurality of upper pieces and lower pieces alternately arranged in a circumferential direction with the pieces axially and circumferentially apart from each other, a coupling piece coupling pieces adjacent to each other, and flange portions formed standing at inner circumferential-side end portions of the upper pieces and the lower pieces so as to press the side rails, and a through hole being formed in the flange portions, wherein side rail support portions that project axially are formed at portions in the circumferential direction of outer circumferential-side end portions of the upper pieces and the lower pieces.

In a combination oil ring, when a line passing through a center of a segment width is a first intermediate line, a length of a line segment between a position on an engine combustion chamber side and a position on a side distant from the engine combustion chamber on a contour curve at a position at a distance of 3 m from an outer peripheral vertex toward an inner peripheral side in a segment radial direction is L, and an intermediate line of the line segment L is a second intermediate line, the second intermediate line is located on the side more distant from the engine combustion chamber than the first intermediate line, and the outer periphery vertex of the segment is located on the second intermediate line or on the side more distant from the engine combustion chamber than the second intermediate line.

A piston ring includes an annular main body portion having an inner peripheral surface, an outer peripheral surface, and one side surface and the other side surface. The piston ring includes a first curved surface provided on the outer peripheral surface, being convexly curved outwards in a radial direction of the main body portion, a second curved surface provided on the outer peripheral surface, being convexly curved outwards in the radial direction of the main body portion, and an intermediate surface formed to extend in a direction connecting the one side surface to the other side surface connecting the first curved surface to the second curved surface. The intermediate surface has a flat portion formed in at least a part thereof. The width of the intermediate surface in the direction connecting the one side surface to the other side surface is 0.05 mm or more and 0.30 mm or less.

A combined oil control ring for automobile engines capable of keeping an excellent oil-controlling function without suffering sticking between a spacer expander and side rails for a long period of operation comprises upper and lower two side rails, and an axially corrugated spacer expander having upper and lower portions; a leg portion connecting each upper portion and each lower portion of the spacer expander having a portion having an inclination angle of 15 or more from the axial direction.

A combined oil control ring comprising a pair of circular side rails each having a gap, and a waved spacer expander longitudinally sandwiched by the side rails, which has seating tabs for pushing inner surfaces of the side rails on the inner side, (a) the radial thickness a.sub.1 of the side rail being 50-90% of the height a.sub.9 of the spacer expander, or (b) the height a.sub.10 of the seating tab being 23-60% of the height a.sub.9 of the spacer expander.

A combination oil ring includes a pair of upper and lower side rails and a spacer expander arranged there between, the spacer expander including a plurality of upper pieces and lower pieces alternately arranged in a circumferential direction with the pieces axially and circumferentially apart from each other, a coupling piece coupling pieces adjacent to each other, and flange portions formed standing at inner circumferential-side end portions of the upper pieces and the lower pieces so as to press the side rails, and a through hole being formed in the flange portions, wherein side rail support portions that project axially are formed at portions in the circumferential direction of outer circumferential-side end portions of the upper pieces and the lower pieces.

A combination oil ring includes a pair of upper and lower side rails and a spacer expander arranged there between, the spacer expander including a plurality of upper pieces and lower pieces alternately arranged in a circumferential direction with the pieces axially and circumferentially apart from each other, a coupling piece coupling pieces adjacent to each other, and flange portions formed standing at inner circumferential-side end portions of the upper pieces and the lower pieces so as to press the side rails, and a through hole being formed in the flange portions, wherein side rail support portions that project axially are formed at portions in the circumferential direction of outer circumferential-side end portions of the upper pieces and the lower pieces.