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 piston ring has an annular base body 2, which is preferably open at a joint, with a U-shaped cross section, the open side of which faces inwards in the radial direction. A ring spring 4 is provided which runs in a meandering manner in the axial direction, and which pretensions the base body 2 outwards in the radial direction. In one section of the ring spring 4, which is located inside the base body, meandering loops 5 bear alternately against the shanks 3 of the U-shaped cross section. In one section of the ring spring 4, which protrudes out of the base body 2, meandering loops 6 bear alternately against the radially inwardly facing edges of the shanks 3 of the U-shaped cross section.

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.

A piston ring system for an internal combustion engine includes a first compression piston ring (2), a second compression piston ring (4), and an oil scraper piston ring (6). The first compression piston ring (2) has a first ring body (8) with a first upper ring flank (10), a first lower ring flank (12), a first ring inner side (14), a first ring outer side (16), as well as two first abutting surfaces. A first contact region (18) of the first ring body (8) is arranged with a cylinder running surface (20) above a first piston ring center (22). At least one first oil pocket (24) is arranged below the first contact region (18) in the circumferential direction. The second compression piston ring (4) having a second ring body (26) a second upper ring flank (28), a second lower ring flank (30), a second ring inner side (32), a second ring outer side (34), as well as two second abutting surfaces. A second contact region (36) of the second ring body (26) is arranged with the cylinder running surface (20) above or below a second piston ring center (38). At least one second oil pocket (40) is arranged below the second contact region (36) in the circumferential direction. The oil scraper piston ring (6) is formed in one piece, two pieces, or three pieces.

An oil control ring according the present disclosure includes a pair of side rails, and a spacer expander disposed between the pair of side rails. The spacer expander includes a plurality of sets and each set includes a lug part and a rail facing part. For each set, the lug part is in contact with an inner circumferential surface of either of the pair of the side rails, and the rail facing part is provided adjacent to the lug part and faces a side surface of either of the pair of the side rails. The lug part satisfies a following condition (1):
W/H≥1.5  (1)
In condition (1), W indicates a width of the lug part at a position 0.05 mm away from a highest position of the lug part in a direction towards the rail facing part, and H indicates a height difference between a highest position of a region on the rail facing part adjacent to the lug part and the highest position of the lug part.

The invention relates to an MF expander spring 20 for a three-part oil scraper ring 2, 4, 6, 8. It comprises a steel band, which is corrugated in a trapezoidal or diamond-shaped manner in the axial direction, wherein the MF expansion spring 20 has axial protrusions 30, 32, which are intended to abut in each case against an upper or lower oil scraper ring 34, 36 from the inside in the radial direction, in order to press said axial protrusions outwards against an inner cylinder surface, comprises upper flat sections 24, which are intended to abut against an upper scraper ring 34, 36 of a three-part oil scraper ring 2, 4, 6, 8 in the axial direction, comprises lower flat sections 23, which are intended to abut against a lower scraper ring 34 of the three-part oil scraper ring 2, 4, 6, 8 in the axial direction, and comprises flank sections 26, 28, which extend between the upper flat sections 24 and the lower flat sections 22. At least every second flank section 26 forms an acute angle (α) with the associated upper or lower flat sections 22, 24.

A multi-piece piston ring includes an upper scraper ring 10 comprising two flank surfaces, an outer scraping surface/edge, and an inner spring contact surface. A lower support ring 4 includes two flank surfaces, an outer spring contact surface, and a support ring inner surface. An expander spring/spiral spring 8, which, on an upper and lower side, is operational to abut against a respective lower flank surface of the upper scraper ring 10 and against the upper flank surface of the support ring 4. Scraper ring contact projections protruding upwards on an inner spring side, and support ring contact projections protruding downwards on an outer spring side, wherein the scraper ring contact projections are to each abut against the inner spring contact surface of the scraper ring 10, and support ring contact projections protruding downwards are to abut against the outer spring contact surface.

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 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.

The present invention relates to an oil scraper ring spring (1) for an oil scraper ring (3) comprising the oil scraper ring spring (1), an upper and a lower metal ring (21, 22) and provided for being mounted in an oil ring groove of a piston. The oil scraper ring spring (1) comprises a plurality of upper regions (5) and a plurality of lower regions (7) arranged in alternating manner in a circumferential direction so as to be spaced in an axial direction; connecting regions (9) each connecting the adjacent upper and lower regions (5, 7) to each other. Each of the upper and lower regions (5, 7) comprises: a nose section (13) disposed at the inner circumferential end and adapted to push the respectively abutting upper or lower metal ring (21, 22) radially outwardly, and having a through-opening (15); an abutment section (17) extending radially between the nose section (13) and the outer circumferential end and configured to have the respective upper metal ring (21) abutting thereon or the respective lower metal ring (22) abutting thereon; wherein the abutment section (17) has a recess (19) formed therein the depth of which, relative to the abutting area of the abutment section (17), increases in the radial direction towards the through-opening (15), and the width of which increases in the radial direction towards the through-opening (15); wherein the recess (19) in the abutment section (17) has substantially the shape of a half-funnel; wherein the half-funnel has an opening angle of 30° to 150°, in particular of 30° to 60°, or wherein the upper side edges of the recess (19) span an angular segment of 5-50°, in particular 5-15°; and wherein increasing the depth and width of the recess (19) radially inwardly together with the through-opening (15) serves to increase and accelerate the oil flow to the piston center.