Abstract: 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.

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, 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 method and an apparatus for measuring the light gap tightness of a piston ring, that is provided with a joint and produced so as to be non-round by clamping the open piston ring, while substantially closing the joint, by way of an accessory device in the circumferential direction, and by exerting a defined force in the region of at least one of the joint ends of the piston ring in the direction of a wall of the accessory device, wherein optical means are used to establish whether the joint region of the piston ring which is subjected to the action of the force is seated against the wall of the accessory device in a light-tight manner.

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 method and an apparatus for measuring the light gap tightness of a piston ring, that is provided with a joint and produced so as to be non-round by clamping the open piston ring, while substantially closing the joint, by way of an accessory device in the circumferential direction, and by exerting a defined force in the region of at least one of the joint ends of the piston ring in the direction of a wall of the accessory device, wherein optical means are used to establish whether the joint region of the piston ring which is subjected to the action of the force is seated against the wall of the accessory device in a light-tight manner.

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: 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.