Abstract: 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.

Abstract: 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.

Abstract: A three-part oil scraper ring includes an upper scraper ring (24), a lower scraper ring (26), wherein the scraper rings (24, 26) are held at a distance by an expander spring (34) and pressed radially outwards. The upper scraper ring (24) has a ring body (4) having an upper flank (6), a lower flank (8), a ring inner surface (10) and a ring outer surface (12) which has a ring outer contour (14) in cross-section in axial direction (A). The ring body (4) has a height H which, when viewed in axial direction (A), corresponds to the greatest distance of the upper flank (6) from the lower flank (8). The ring outer contour (14) forms a running surface (16) which has a radius of curvature R which is smaller than the height H of the upper scraper ring (24) by a factor between 1.5 to 6.

Abstract: 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.

Abstract: A three-part oil scraper ring includes an expander spring and two scraper rings, comprising a ring body (4) having an upper flank (6), a lower flank (8), a ring inner surface (10) and a ring outer surface (12) which has a ring outer contour (14) in cross-section in axial direction (A). The ring body (4) has a height H which corresponds to the greatest distance of the upper flank (6) to the lower flank (8). The ring outer contour (14) forms a running surface (16) which has a radius of curvature R which is smaller than the height H of the scraper ring (2) by a factor between 1.5 to 6, preferably between 3 to 5 and further preferably between 3.5 to 4.5.

Abstract: A piston ring with improved wear properties has a running surface, an upper ring flank, a lower ring flank, and an inner surface. The piston ring has a radius R, and wherein in a radial section, a running surface contour includes an upper region, a central region, and a lower region. The upper region of the running surface contour has a curvature radius Ro, which lies between the ring radius R and infinity. The central region of the running surface contour has a curvature radius Rm, which lies between the ring radius R and infinity. The lower region has a curvature radius Ru, which is smaller than the ring radius R.

Abstract: A piston ring has a running surface, an inner surface, a lower ring flank, and an upper ring flank. A recess, extending across the perimeter in the shape of an internal angle, is located at the transition between the inner surface and the upper ring flank. The recess defines a conical first surface and a conical second surface at the piston ring. The first surface lies farther outward, when viewed in the radial direction, and farther above, when viewed in the axial direction, than the second surface. In an axial cross section, a first angle between the axial direction and the first surface lies in the range between 10° and 50°, and a second angle between the radial direction and the second surface lies in the range between 5° and 30°. A piston having a piston ring groove includes a projection on the groove bottom. A combination made from an above-mentioned piston ring and an above-mentioned piston are adapted to one another, so that the projection projects into the recess.

Abstract: A piston ring (10) has a running surface (12) and a flank surface (14) which are coated. The uppermost layer of the running surface (12) is a hydrogen-containing or a hydrogen-free DLC layer, and the uppermost layer of at least one flank surface (14) is a chromium layer. A method of producing a piston ring (10) includes forming a DLC layer as the uppermost layer of the running surface (12), and forming a chromium layer as the uppermost layer of at least one flank surface (14).

Abstract: A piston ring is provided, in particular a compression piston ring having at least one recess with a lower edge running obliquely to the upper piston ring flank on its upper piston ring flank, the ring flank extending radially outward from the piston ring interior and radially inward from the piston ring bearing surface. The piston ring has a chamfer, which is opposite at least one recess. At least one recess and the chamfer extend in the radial direction up to at most the center of the cross-sectional area of the piston ring.

Abstract: A play-free oil scraper ring has a cross section with a running surface leg having at least one scraper web that is situated on a running surface, an upper piston ring flank leg that is connected to the running surface leg, and the upper surface of which forms an upper piston ring flank. A lower piston ring flank leg is likewise connected to the running surface leg, the lower surface of which forms a lower piston ring flank. The upper and/or the lower piston ring flank leg are/is elastic, taper(s) inwardly in the radial direction, and their/its piston ring flank(s) essentially form(s) a conical surface in an uninstalled state. The uninstalled piston ring has an axial height that exceeds a width of a piston ring groove for which the piston ring is intended.

Abstract: A stepped piston ring (2) includes a ring outer side (5), an upper ring flank (6), and a lower ring flank (8). The ring outer side (5) on the upper edge has a notch (10, so that only a lower portion of the ring outer side (5) forms a contact surface (4).

Abstract: A three-piece piston oil control ring 2 has an upper, disc-shaped scraping ring 4, a lower, disc-shaped stabilising ring 6, and a circular expander 8 which has projections 10 protruding in the axial direction on an inner face. The circular expander 8 is arranged between the upper scraping ring 4 and the lower stabilising ring 6, wherein the projections 10 each bear inwardly against an inner face 14 of the scraping ring 4 or against an inner face 16 of the stabilising ring 6. An outer radius 18 of the scraping ring 4 is greater than an outer radius 20 of the lower stabilising ring 6, so that there is a radius difference ? between the scraping ring 4 and the stabilising ring 6.

Abstract: A piston ring, and in particular a compression piston ring, has a running face, upper and lower flank regions, an inner circumferential surface and a joint, wherein at least the running face is provided with at least one wear-resistant PVD or CVD layer, wherein the PVD or CVD layer extends at a predefinable layer thickness across a circumferential length of more than 95%, but less than 100% of the piston ring, and defined circumferential sections are designed in a layer-free manner in the region of the joint.

Abstract: A piston ring is produced from a main body made of steel or cast steel and comprising a running face, an inner circumferential surface, upper and lower flank regions, and transition regions from the running face to the respective flank region, by coating the running face and the transition regions with a first chromium layer, removing this first chromium layer at the running face down to the base material of the main body, providing at least the running face of the layer-free main body with a nitride layer, and, finally, coating the running face and the transition regions with at least one further chromium layer.

Abstract: A sliding element, in particular a piston ring, has a coating which has the following layers from the inside outwards: a polycrystalline, metal-containing adhesive layer, an intermediate layer, and at least one amorphous carbon layer, the intermediate layer having the following partial layers from the inside outward: an AxCy layer, with c standing for carbon, A standing for a metal, preferably of the metal-containing adhesive layer, and x as well as y each comprising values of 1-99, and a crystalline-containing or crystal-containing carbon layer.

Abstract: A one-piece control ring with two stripping ridges and openings that extend from the outside of the ring to the inside is provided wherein the cross section of the ring body varies in the circumferential direction. This variation is achieved with internal grooves, the cross-sectional area of which decreases in the direction of the back of the ring, and with a variation of the depth of the groove lying between the ridges.

Abstract: A compression piston ring is provided, in particular a piston ring suitable as a second piston ring in a three-ring piston ring set, which piston ring has convex sections and concave sections alternating in the circumferential direction in a middle running face region in relation to the axial height, wherein the concave sections form profile recesses in the convexly crowned running face.

Abstract: An oil wiper ring is provided having two circumferential shoulders, the running surfaces whereof are outwardly curved, wherein the shoulder of the combustion chamber side has an axial height greater by at least a factor of 2 than the axial height of the shoulder on the crankcase side and wherein the should on the combustion chamber side has an asymmetrical crowning.

Abstract: The present invention relates to a two-part oil scraper ring, which comprises an L-shaped base body and an axial stabilization element. The L-shaped base body has a ring flank leg, which is pressed against a piston ring groove flank by the axial stabilization element, and a bearing surface leg, on which a scraping web is arranged. A twist compensation is attained by means of a suitable selection—and in particular variation—of hearing surface leg length, ring flank leg length and axial position of the scraping web.

Abstract: A sliding element, in particular a piston ring has an outer circumferential running surface of the piston ring, has no nitriding layer, preferable no surface hardening the running surface has as an outermost layer, which differs from the intermediate layer, a DLC layer or a metal-based nitride layer, preferable a metal nitride layer, preferably a CrN layer. Provided between the substrate of the sliding element and the DLC layer there is at least one metal-containing intermediate layer, preferably a metal layer, particularly preferable a chromium layer, and at least one further surface of the sliding element, preferably the piston ring flanks, is surface-hardened, preferably has a nitriding layer.