The present invention addresses the problem of providing a piston ring covered with a DLC coating that has excellent wear resistance and shows a low attacking property on a cylinder bore sliding surface. The problem is solved by a piston ring which is used in the presence of an engine lubricating oil and includes a DLC coating on an outer peripheral sliding surface. The DLC coating has an sp.sup.2 component ratio of 0.5 to 0.85 as determined from a TEM-EELS spectrum obtained by a combination of a transmission electron microscope (TEM) and electron energy loss spectroscopy (EELS), as well as a coating hardness of 12 GPa to 26 GPa and a Young's modulus of 250 GPa or less as measured by a nanoindentation method.

A three-piece oil ring for an internal combustion engine may include an expanding element defining at least a first side and a second side opposite the first side. A first upper annular segment may be associated with the first side of the expanding element. A second lower annular segment may be associated with the second side of the expanding element. The first annular segment and the second annular segment may each include a first internal side surface and a second external side surface. A metallic tungsten matrix coating may be disposed on at least one of the expanding element, the first annular segment and the second annular segment via chemical vapor deposition. The coating may contain a tungsten nanocarbide that may include at least one of WC, W2C, W3C and W12C. The coating may include a thickness between 5 μm and 150 μm and a hardness between 1000HV and 3500HV.

A three-piece oil ring for an internal combustion engine may include an expanding element defining at least a first side and a second side opposite the first side. A first upper annular segment may be associated with the first side of the expanding element. A second lower annular segment may be associated with the second side of the expanding element. The first annular segment and the second annular segment may each include a first internal side surface and a second external side surface. A metallic tungsten matrix coating may be disposed on at least one of the expanding element, the first annular segment and the second annular segment via chemical vapor deposition. The coating may contain a tungsten nanocarbide that may include at least one of WC, W2C, W3C and W12C. The coating may include a thickness between 5 μm and 150 μm and a hardness between 1000HV and 3500HV.

A sealing assembly for a pump includes a header ring having a tapered radially outer surface and a sloped radially inner surface. The assembly also includes a first seal configured to couple to the header ring, the first seal having a groove that receives a bead extending from the header ring. The assembly further includes a second seal axially aligned with the first seal.

A piston ring (2) having increased fatigue resistance includes a plastically deformable material. The piston ring (2) has a running face (4), which is delimited at the top by an upper running face edge (3) and at the bottom by a lower running face edge (1). Compressive stresses are introduced into the upper running face edge (3) and/or into the lower running face edge (1) along at least one part of the circumference, the compressive stresses having been produced by roller burnishing.

A piston ring (2) having increased fatigue resistance includes a plastically deformable material. The piston ring (2) has a running face (4), which is delimited at the top by an upper running face edge (3) and at the bottom by a lower running face edge (1). Compressive stresses are introduced into the upper running face edge (3) and/or into the lower running face edge (1) along at least one part of the circumference, the compressive stresses having been produced by roller burnishing.

In a method for coating a sliding element, in particular a piston ring or a cylinder liner of an internal combustion engine, DLC phases are embedded into a hard material layer as said hard material layer is deposited. A sliding element, such as a piston ring or a cylinder liner of an internal combustion engine, comprises a hard material layer with embedded DLC phases.

In a method for coating a sliding element, in particular a piston ring or a cylinder liner of an internal combustion engine, DLC phases are embedded into a hard material layer as said hard material layer is deposited. A sliding element, such as a piston ring or a cylinder liner of an internal combustion engine, comprises a hard material layer with embedded DLC phases.

A piston ring may include a metallic base, an outer slide layer and an intermediate layer disposed between the base and the outer slide layer. The base may extend between at least two end regions. The outer slide layer and the intermediate layer may be disposed on an outer radial face of each end region of the base.

A piston ring may include a metallic base, an outer slide layer and an intermediate layer disposed between the base and the outer slide layer. The base may extend between at least two end regions. The outer slide layer and the intermediate layer may be disposed on an outer radial face of each end region of the base.