Patent ID: 6793222
Filing Date: 2004-09-21
Classification: F16J

Abstract:
An oil scraper piston ring comprising a split ring having end faces oriented toward one another and defining a ring gap, and further including(a) an inner circumferential surface; (b) a closed outer circumferential surface adapted to contact and slide along an inner wall of an engine cylinder; (c) a radial wall thickness defined by a radial distance between said inner and outer circumferential surfaces; and (d) a plurality of circumferentially distributed recesses extending exclusively from said inner circumferential surface, with each recess extending radially from said inner circumferential surface toward said outer circumferential surface for reducing said radial wall thickness; each recess including (1) a first recess region open at said inner circumferential surface and extending radially toward said outer circumferential surface; said first recess region having a first contour shape and a first area; and (2) a second recess region merging into said first recess region and having a second contour shape and a second area; said second contour shape being different from said first contour shape and said second area being larger than said first area; and (e) said ring gap has a width larger than a circumferentially measured maximum dimension of said first recess region.