Compression oil control piston ring

Patent metadata

Field	Value
Publication number	US-10969013-B2
Application number	US-201716306071-A
Country	US
Kind code	B2
Filing date	May 22, 2017
Priority date	Jun 1, 2016
Publication date	Apr 6, 2021
Grant date	Apr 6, 2021

Abstract

A compression piston ring is provided, in particular a piston ring suitable as a second piston ring in a three-ring piston ring set, which piston ring has convex sections and concave sections alternating in the circumferential direction in a middle running face region in relation to the axial height, wherein the concave sections form profile recesses in the convexly crowned running face.

First claim

The invention claimed is:

1. A piston ring for an internal combustion engine, comprising a piston ring body having, an outer running face divided into regions which extend around in the circumferential direction over different axial height regions of the running face, said regions comprising
an upper running face region on a combustion chamber side,
a lower running face region on a crankcase side, and
a middle running face region between the upper and lower running face regions;

wherein the boundary line between the upper and middle running face regions forms a scraping line,
wherein the boundary line between the middle and lower running face regions forms a crest line,
wherein the scraping line runs radially further outwards than the crest line;
wherein the upper and lower running face regions are curved convexly outwards over their entire axial height, as viewed in axial cross-section;
wherein the middle running face region has, alternating in the circumferential direction, convex sections which are curved convexly outwards as viewed in axial cross-section, and concave sections which are at least partially curved concavely inwards as viewed in axial cross-section; and
wherein the circumference of the piston ring includes a ring gap which forms an interruption in the circumference that extends fully through the radial width of the piston ring.

2. The piston ring according to claim 1 , wherein the crest line lies radially further outwards than at least one radially innermost point of the concave sections.

3. The piston ring according to claim 1 , wherein the radial distance between the scraping line and the at least one radially innermost point of the concave sections is less than five times the radial distance between the scraping line and the crest line.

4. The piston ring according to claim 1 , wherein the running face is smooth, without edges between the running face regions Bo, Bu, Bm, in every axial cross-sectional view.

5. The piston ring according to claim 1 , wherein the concave sections and the convex sections of the middle running face region merge smoothly into each other without forming edges.

6. The piston ring according to claim 1 , wherein the middle running face region has 3-30, of said concave sections in the circumferential direction.

7. The piston ring according to claim 6 , wherein there are 8-24 of said concave sections.

8. The piston ring according to claim 6 , wherein there are 2-18 of said concave sections.

9. The piston ring according to claim 1 , wherein each of the convex sections extends over an angle of at least 5° in the circumferential direction.

10. The piston ring according to claim 1 , wherein the end regions of the running face which are adjacent to the ring gap form a convex section.

11. The piston ring according to claim 1 , wherein the scraping line and the crest line have a substantially constant distance from a piston ring flank in the circumferential direction.

12. The piston ring according to claim 1 , wherein the distance in the radial direction between the scraping line and the crest line is substantially constant in the circumferential direction.

13. The piston ring according to claim 1 wherein the scraping line runs, measured from the flank on the crankcase side, at an axial height of 45-70% of the total axial height of the piston ring.

14. The piston ring according to claim 13 , wherein said axial height is 50-60% of said total axial height.

15. The piston ring according to claim 1 , wherein the running face forms a closed face, there being no openings running through the piston ring to the piston ring inner side.

16. A piston ring for an internal combustion engine, comprising:
a circumferentially extending piston body having a top, bottom inner and outer surfaces;
a ring gap forming a physically break in the piston body and extending through the top, bottom, inner and outer surfaces;
the outer surface presenting an outer running face having at least three regions, including an upper region, a lower region and a middle region of the running face;
a common boundary between the upper and middle regions forming a scraping line;
a common boundary between the middle and lower regions forming a crest line disposed radially inwardly of the scraping line;
the upper and lower regions being outwardly convexly curved over a full axial height of each of the upper and lower regions; and
wherein the middle region has convexly outwardly curved sections interrupted by intervening concave sections.

Assignees

• Fed Mogul Burscheid Gmbh

Inventors

• Mittler Richard
• Ruch Fabian

Classifications

• F16J9/206 Primary

  One-piece oil-scraping rings · CPC title

• F16J9/20

  Rings with special cross-section (L-section rings F16J9/02); Oil-scraping rings {(F16J9/06 takes precedence)} · CPC title