Coated piston ring for an internal combustion engine

Patent metadata

Field	Value
Publication number	US-2022364643-A1
Application number	US-202117318530-A
Country	US
Kind code	A1
Filing date	May 12, 2021
Priority date	May 12, 2021
Publication date	Nov 17, 2022
Grant date	—

Abstract

A coated piston ring for a piston is provided. The piston ring includes a running surface, a flank surface, and a transition surface therebetween. The transition surface curves or extends at an angle between the running surface and the flank surface. A running layer is disposed over the running surface and over at least a portion of the transition surface. A flank layer is disposed over the flank surface and over at least a portion of the transition surface. The running layer is applied by physical vapor deposition, and the running layer is applied by galvanic deposition. The running layer is formed of chromium nitride, and the flank layer is formed of chromium. A portion of the flank layer overlaps and is disposed outward of a portion of the running layer. During operation of the piston, the overlapping portion is spaced from both the piston and the cylinder.

First claim

What is claimed is:

1 . A piston ring, comprising:
a body portion including a running surface, a flank surface, and a transition surface between said running surface and said flank surface; a running layer disposed over said running surface and over at least a portion of said transition surface, said running layer being formed of chromium nitride; a flank layer disposed over said flank surface and over at least a portion of said transition surface, said flank layer being formed of chromium; and a portion of said flank layer and a portion of said running layer overlapping one another.

2 . The piston ring of claim 1 , wherein said portion of said flank layer which overlaps said running layer is disposed outward of said running layer.

3 . The piston ring of claim 1 , wherein said running layer is applied by physical vapor deposition.

4 . The piston of claim 1 , wherein said flank layer is applied by galvanic deposition.

5 . The piston of claim 1 , wherein said running layer and said flank layer provide outermost surfaces of said piston ring.

6 . The piston ring of claim 1 , wherein said body portion is formed of an iron-based material and extends around a center axis, said running surface is parallel to said center axis, and said flank surface is transverse to said center axis.

7 . The piston ring of claim 1 , wherein a majority of said transition surface extends at an angle from said flank surface toward said running surface, said body portion includes a first sharp corner between said transition surface and said flank surface, said transition surface rounds as it approaches said running surface, and said round portion of said transition surface presents a convex shape.

8 . The piston ring of claim 7 , wherein said running layer is disposed on a portion of said transition surface, and said flank layer is disposed on a portion of said running layer and over an entirely of said transition surface.

9 . The piston ring of claim 1 , wherein a majority of said transition surface is disposed at an angle between said flank surface and said running surface, said transition surface presents a concave shape as it approaches said flank surface, said body portion includes a first sharp corner between said transition surface and said flank surface, said transition surface rounds as it approaches said running surface, and said transition surface presents a convex shape as it approaches said running surface.

10 . The piston ring of claim 9 , wherein said running layer is disposed on an entirely of said transition surface, said flank layer is disposed on a portion of said running layer and over a portion of said transition surface.

11 . The piston ring of claim 1 , wherein said transition surface presents a convex shape extending from said lower flank surface to said running surface.

12 . The piston ring of claim 11 , wherein said running layer is disposed on an entirely of said transition surface, said flank layer is disposed on a portion of said running layer and over a portion of said transition surface.

13 . A piston assembly, comprising:
a piston including a ring groove; a piston ring disposed in said ring groove of said piston; said piston ring including a running surface, a flank surface, and a transition surface between said running surface and said flank surface; said piston ring including a running layer disposed over said running surface and over at least a portion of said transition surface, said running layer being formed of chromium nitride; said piston ring including a flank layer disposed over said flank surface and over at least a portion of said transition surface, said flank layer being formed of chromium; a portion of said flank layer and a portion of said running layer overlapping one another; and said overlapping portion of said flank layer and said running layer being spaced from said ring groove of said piston.

14 . The piston assembly of claim 13 , wherein said piston is disposed in a cylinder;
and said overlapping portion of said flank layer and said running layer is spaced from said cylinder.

15 . The piston assembly of claim 13 , wherein said portion of said flank layer which overlaps said running layer is disposed outward of said running layer.

16 . The piston assembly of claim 13 , wherein said running layer and said flank layer provide outermost surfaces of said piston ring.

17 . The piston assembly of claim 13 , wherein said transition surface extends at an angle or curves between said flank surface and said running surface.

18 . A method of manufacturing a piston ring, the piston ring comprising a body portion including a running surface, a flank surface, and a transition surface between said running surface and said flank surface; the method including:
applying a running layer over the running surface and over at least a portion of the transition surface by a physical vapor deposition process; applying a flank layer over the flank surface and over at least a portion of the transition surface by a galvanic deposition process such that a portion of the flank layer overlaps a portion of the running layer.

19 . The method of claim 18 , wherein the running layer is formed of chromium nitride.

20 . The method of claim 18 , wherein the flank layer is formed of chromium.

Assignees

• Tenneco Inc

Inventors

• Dufek Daniel J
• Irrgeher Marc

Classifications

• F16J9/12

  Details · CPC title

• C25D3/04

  of chromium · CPC title

• C23C28/34

  including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates · CPC title

• F16J9/26 Primary

  characterised by the use of particular materials · CPC title

• C23C14/0641

  Nitrides (C23C14/0617 takes precedence) · CPC title