Piston ring for internal combustion engines

Patent metadata

Field	Value
Publication number	US-10995857-B2
Application number	US-201916600487-A
Country	US
Kind code	B2
Filing date	Oct 12, 2019
Priority date	Apr 12, 2017
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

A piston ring for internal combustion engines provided with a ferrous alloy base includes an annular outer surface on which a coating including at least one outer layer is applied deposited on an adhesive layer, the outer layer being provided with a variable thickness, in such a way that the thickness of the outer layer gradually increases from 90° and 270° towards 0° and 360° respectively, with the thickness attaining its maximum value in the region of 10° and 350° and slightly decreasing towards 0° and 360° so as to ensure an optimal working condition, minimizing the contact pressure and consequently the accelerated wear in the vicinities of the ends of the ring, in addition to preventing and/or impeding the detachment of the outer layer of the coating.

First claim

What is claimed is:

1. A piston ring for an internal combustion engines, the piston ring comprising:
a ferrous alloy base including an annular outer surface on which a coating that includes at least one outer layer is applied,
the at least one outer layer being formed of amorphous carbon a-C and deposited on at least one adhesion layer, the at least one outer layer having a variable thickness along a circumference of the piston ring,
wherein a ratio that corresponds to the circumference of the piston ring between first points on the at least one outer layer at circumferential angles of 90° and 270° and second points on the at least one outer layer in vicinities of circumferential angles of 0° and 360° is from 0.20 to 0.50, and such that the thickness of the at least one outer layer gradually increases from the first points to the second points.

2. The piston ring according to claim 1 , wherein the at least one adhesion layer is formed of chromium.

3. The piston ring according to claim 1 , wherein the at least one adhesion layer has a thickness equal to or greater than 5% of the thickness of the at least one outer layer at a circumferential angle of 180°.

4. The piston ring according to claim 1 , wherein the at least one adhesion layer has a thickness of between 0.1 and 1.2 micrometers.

5. The piston ring according to claim 1 , further comprising:
a first end and a second end of the piston ring forming an opening therebetween with a center of the opening at the circumferential angles 0° and 360°;
a first half of the piston ring including the opening being defined by the circumferential angles from 270° to 360° and from 0° to 90° in a clockwise direction; and
a second half of the piston ring excluding the opening being defined by the circumferential angles from 90° to 270° in the clockwise direction, wherein:
the at least one outer layer has a thickness at the second points in regions at circumferential angles of 10° and 350° which is reduced towards the first and second ends of the piston ring, and
the at least one outer layer has a uniform thickness in the second half of the piston ring.

6. The piston ring according to claim 5 , wherein the at least one outer layer has a thickness of at least 5 micrometers in the second half of the piston ring, and from the first points to the second points, the at least one outer layer gradually becomes thicker until attaining a thickness of at least 10 micrometers at the second points, and such that a maximum thickness in the regions at the circumferential angles of 10° and 350° is 60 micrometers.

7. The piston ring according to claim 1 , wherein the annular outer surface is a sliding surface.

8. The piston ring according to claim 1 , wherein the piston ring relates to a first piston groove compression ring and/or a second piston groove compression ring.

9. An internal combustion engine comprising at least one of the piston ring according to claim 1 .

Assignees

• Mahle Metal Leve Sa
• Mahle Int Gmbh

Inventors

• Avelar Araujo Juliano
• Costa Nuno
• Da Rocha Mordente Paulo José
• Lima Sarabanda José Valentim

Classifications

• F16J9/26 Primary

  characterised by the use of particular materials · CPC title

• C23C14/588

  by mechanical treatment · CPC title

• C23C14/505

  for rotation of the substrates · CPC title

• C23C14/025

  Metallic sublayers · CPC title

• C23C14/0605

  Carbon · CPC title