METHOD FOR PRODUCING PISTON A RING

摘要

A piston ring is produced in which a piston ring base body made of cast iron or cast steel is coated with at least one PVD layer having a variable layer thickness, such that an increased layer thickness is present in the region of the ring ends compared to the remaining circumferential region of the piston ring base body, wherein the piston ring base body is configured so that, in the cold operating state with the engine not running, the radial pressure distribution of the piston ring base body is such that the ring ends exhibit substantially no radial pressure across a defined circumferential angle, and the variable layer thickness of the PVD layer is set so that a substantially uniform radial pressure distribution is present along the entire ring circumference of the piston ring at a piston ring temperature above 150° C.

主权项

1. A method for producing a piston ring, comprising providing a piston ring base body made of cast iron or cast steel and having ends separated by a gap comprising a joint, coating an outer circumferential surface of the piston ring base body with at least one PVD layer of varying thickness which is greater in a region of each of the ring ends of predetermined circumferential angle than in a remaining circumferential region of the circumferential surface thereby to produce a piston ring having a running face formed of a PVD layer, wherein the piston ring base body is configured so that, installed in a cold engine which is not running, the radial pressure distribution of the piston ring is such that the ring ends over said predetermined circumferential angle exhibit substantially no radial pressure and the varying of the thickness of the PVD layer is predetermined so that radial pressure over the entire piston ring circumference at a piston ring temperature above 150° C. is substantially uniform.