Multi-piece oil ring

Patent metadata

Field	Value
Publication number	US-10330198-B2
Application number	US-201816015987-A
Country	US
Kind code	B2
Filing date	Jun 22, 2018
Priority date	Sep 30, 2009
Publication date	Jun 25, 2019
Grant date	Jun 25, 2019

Abstract

A multi-piece oil ring includes an oil ring main member in which two rails are connected together by a columnar part and which has a roughly I-shaped cross section; and a coil expander disposed in an inner circumferential groove formed on the inner circumferential surface of the columnar. Each rail in the oil ring main member possesses a sliding section protuberance whose tip possesses a jutting portion. The axial length of the jutting portion is 0.02-0.18 mm. The change rate of the axial length of the individual jutting portion is in the range of 0 to 80% at least in a region of from its sliding surface to be faced to a cylinder, which is positioned at the tip of the jutting portion, to a position of 0.03 mm away from the aforementioned sliding surface in the radial direction of the oil ring main member.

First claim

The invention claimed is:

1. A multi-piece oil ring comprising:
an oil ring main member in which two rails arranged in an axial direction are connected together by a columnar part and which has a roughly I-shaped axial cross section; and
a coil expander which is placed in an inner circumferential groove formed on an inner circumferential surface of the columnar part of the oil ring main member, and which applies force to the oil ring main member in such a way as to press the same outwardly in a radial direction of the oil ring main member,
wherein each of the two rails in the oil ring main member comprises an individual protuberance extending from a top surface of the rail outwardly in the radial direction, the protuberance having a first portion and a second portion respectively,
the first portion being formed at a tip of the protuberance as a jutting portion with a sliding surface configured to engage with an associated piston cylinder, a first surface having a taper shape, a second surface having a concave shape, and a third surface which is parallel to the sliding surface and is formed between the second portion and the second surface,
the second portion being formed between the first portion and the top surface of the rail, and having a taper shape that tapers off towards the sliding surface, the second portion having a first side and a second side opposite from the first side arranged along the axial direction,
the first side of the second portion being formed by continuously linearly connecting to the first surface and by tapering off from the top surface of the rail to the first surface, and
the second side of the second portion being formed by connecting to the second surface of the first portion via the third surface of the first portion and by continuously linearly tapering off from the top surface of the rail to the third surface;

wherein the second surface of the first portion is formed at either an outer side of the sliding surface or at an inner side of the sliding surface in the axial direction of the protuberance facing towards or away from the other protuberance, the second surface of the first portion continuously tapers off from the third surface of the first portion to the sliding surface and forms a concavity in axial cross section and in the direction towards the first surface of the first portion, the concavity of the second surface of the first portion connects to the second side of the second portion via the third surface of the first portion.

2. The multi-piece oil ring according to claim 1 , wherein at least one of the second surfaces faces away from the other protuberance.

3. The multi-piece oil ring according to claim 1 , wherein at least one of the second surfaces faces towards the other protuberance.

4. The multi-piece oil ring according to claim 1 , wherein one of the second surfaces faces away from the other protuberance, and another of the second surfaces faces towards the other protuberance.

5. The multi-piece oil ring according to claim 1 , wherein the oil ring main member has undergone a nitriding treatment.

6. The multi-piece oil ring according to claim 1 , further comprising a physical vapor deposition (PVD) coating and/or a diamond-like carbon (DLC) coating formed on each of the sliding surfaces.

7. The multi-piece oil ring according to claim 1 , wherein the axial length of each individual jutting portion is in the range of 0.05 to 0.17 mm.

8. The multi-piece oil ring according to claim 1 , wherein each individual first portion has a length in the radial direction in the range of 0.03 to 0.10 mm.

9. The multi-piece oil ring according to claim 1 , wherein the oil ring main member is made of a member selected from the group consisting of: 8Cr type steel, SUS410J1 equivalent steel, SWRH77B equivalent steel, and SUS404B equivalent steel.

Assignees

• Nippon Piston Ring Co Ltd

Inventors

• Chiba Atsushi
• Fujimura Kazuhiro
• Hiraishi Iwao
• Kajiwara Makoto

Classifications

• F16J9/062

  Coiled spring along the entire circumference · CPC title

• F16J9/206 Primary

  One-piece oil-scraping rings · CPC title