Abstract: A scraper ring is provided with a plurality of sealing sections on the radially inner circumferential surface, each including a scraping edge, wherein the sealing sections are spaced axially apart from each other by inner circumferential grooves, with at least one recess provided on the circumference of the scraper ring which extends at least partially from a first axial ring end to a second axial ring end and extends at least partially in a direction different from the axial direction of the scraper ring. At least one drainage opening is provided on the outer circumferential surface of the scraper ring, which is connected to at least one inner circumferential groove for removing scraped oil from the inner circumferential grooves.

Abstract: Method for producing a piston ring having an axial height <2 mm, said piston ring having a radially outer running surface provided with at least one rail, a radially inner circumferential surface, and upper and lower flank surfaces extending therebetween, wherein said rail is provided with a contour that is tapered radially outwardly, thereafter the running surface, together with the flanks of the tapered rail, is provided with at least one wear-resistant layer, and then only the flank of the rail that is to form a scraping edge is subjected to at least partial material removal to form the scraping edge.

Abstract: A piston ring is formed from a ring blank, e.g., a wire, that has a cross sectional profile including upper and lower surfaces that are generally parallel and disposed between inner and outer peripheral faces. The cross sectional profile also includes a hook area at the outer portion of the lower surface that includes a nose area. The nose area is provided with a radius that is as sharp as possible, and is disposed such that a grinding operation performed on the lower surface, e.g., with a single generally planar grinding surface, will also grind the nose area, thereby truncating the nose area and increasing sharpness of the nose area without having to perform additional machining operations.

Abstract: A tangential grinding resistance measuring method includes obtaining an abrasive grain section area which is at a predetermined infeed depth from the highest top surface of abrasive grains on a grinding wheel; calculating the tangent of a half vertex angle of a conical model for cutting edges of the abrasive grains which model takes the abrasive grain section area as its bottom surface and the predetermined depth as its height; setting grinding parameters; and calculating a tangential grinding resistance from the grinding parameters and the tangent.

Abstract: A method of manufacturing an oil ring is disclosed. The oil ring includes an annular oil ring body having a pair of rail portions at its axially upper and lower portions and butt ends, and a coil expander assembled in the inner periphery of the oil ring body. A number of oil ring bodies and annular spacers having a smaller diameter than the oil ring bodies are stacked, and then aligned and retained using a jig such that an outer periphery of the oil ring bodies becomes a circle. The aligned oil ring bodies are rotated and a flat region that is substantially level with respect to the outer peripheral sliding surface of the plurality of oil ring bodies is formed. Curved regions extending on both sides of that flat region are formed using a buff or an elastic grindstone.

Abstract: The present invention relates to a piston ring (10), particularly a compression ring, for an internal combustion engine, comprising a ring-shaped body (11) having a ring joint formed by butt ends (14a, 14b), the ring-shaped body (11) further having a ring contact face (12) along its perimeter, for contacting a cylinder wall in operation. According to the invention, the ring contact face (12) has a barrel-shaped profile, the barrel-shaped profile having in any of its cross-sections an area of maximum curvature, whose radius of curvature increases in the direction of the butt ends (14a, 14b).

Abstract: A coating apparatus comprising a pocket section for spreading a coating solution across the coating width, a coating solution supply port for supplying this coating solution to the pocket section, and a slit section for discharging the coating solution from the pocket section to an object to be coated, the above-mentioned coating apparatus using a die coater incorporating at least two bars. In this coating apparatus, these bars are suspended with the end face of one them facing upward. After having been heat-treated in a heat treating furnace, these bars are treated by grinding.

Abstract: A method of making an oil scraper piston ring includes the following steps of providing a base ring body including a circumferential web having flanks and an outer circumferential surface; galvanically depositing on the web a wear resistant hard chromium layer having solid particles embedded therein; applying a break-off resistant cover layer to the hard chromium layer; and grinding the cover layer to provide the outer circumferential surface of the web with sharp bounding edges