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 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: 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: 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: 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 method for producing piston rings, in particular compression piston rings, in which at least one main element is machined in such a way that a circumferential surface serving as a running surface is provide with a wear-resistant layer of a predeterminable layer thickness, wherein a number of piston ring, in particular compression piston rings, brought together to form an assembly, are machined cylindrically in the region of their circumferential surface, a wear-resistant electrodeposited layer of chrome is applied to the finished machined cylindrical circumferential surface, so that the wear-resistant layer has a constant layer thickness within the assembly as a whole, and subsequently the layer is machined in such a way as to produce a running surface that has a region of maximum layer thickness and at least one region of minimum layer thickness.

Abstract: A piston ring has a piston ring basis element, of a material having a first thermal expansion coefficient, a wear protection layer, arranged on a radially outer face of the piston ring, that is made of a material having a second thermal expansion coefficient being smaller than the first thermal expansion coefficient, and including an intermediate layer, arranged between the piston ring basis element and the wear protection layer. The intermediate layer is made of a material having a third thermal expansion coefficient, that is bigger than the first thermal expansion coefficient.

Abstract: In a method for coating at least part of the inner face of a piston ring, said ring preferably consisting of cast iron or steel, a PVD and/or DLC coating is applied by means of at least one of the following methods: PA-CVD, glow discharge and/or HIPIMS. A piston ring has a coating that is formed at least on part of the inner face of said ring, said coating being a PVD and/or DLC coating that preferably has been applied by means of PA-CVD, glow discharge and/or HIPIMS.

Abstract: An oil wiper ring, comprising a body with a radially external running surface, an inner circumferential surface and an upper and lower face, and which possesses at least two slide ribs, which may be provided with a wear-resistant layer, such ribs becoming conically thinner, in the radial direction of their end faces, and which are opposite a sliding mating surface, such that they proceed from the body, at a specifiable angle, in order to form an angled side face, so that the free end of each slide rib, commencing in the region at the oil chamber side, is shaped to slope towards an area at the combustion chamber side, such that the associated transitional areas, on the one hand, from the region of the circumferential slide rib towards the angled side faces, and on the other hand, from the angled side faces to the piston ring body, are rounded, i.e. have predetermined radii.

Abstract: A method for producing piston rings, in particular compression piston rings, in which at least one main element is machined in such a way that a circumferential surface serving as a running surface is provide with a wear-resistant layer of a predeterminable layer thickness, wherein a number of piston ring, in particular compression piston rings, brought together to form an assembly, are machined cylindrically in the region of their circumferential surface, a wear-resistant electrodeposited layer of chrome is applied to the finished machined cylindrical circumferential surface, so that the wear-resistant layer has a constant layer thickness within the assembly as a whole, and subsequently the layer is machined in such a way as to produce a running surface that has a region of maximum layer thickness and at least one region of minimum layer thickness.