Multi-piece oil ring

Patent metadata

Field	Value
Publication number	US-10030772-B2
Application number	US-201013497417-A
Country	US
Kind code	B2
Filing date	Mar 26, 2010
Priority date	Sep 30, 2009
Publication date	Jul 24, 2018
Grant date	Jul 24, 2018

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, the oil ring main member being made of steel; 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, a tip of the protuberance comprising a jutting portion with a sliding surface configured to engage with an associated piston cylinder and a curved surface, the protuberance having a taper shape that tapers off to the sliding surface; the protuberance having a first side and a second side opposite from the first side arranged along the axial direction, the first side continuously linearly tapering off from the top surface of the rail to the sliding surface of the jutting portion, the second side continuously linearly tapering off from the top surface of the rail to the curved surface of the jutting portion,
wherein the curved surface of the jutting portion is formed on the second side of the protuberance, the curved surface being 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 curved surface having a taper shape that continuously tapers off to the sliding surface and a concave curved shape in axial cross section, the concave curved shape being concave in the direction towards the first side of the individual protuberance, the concave curved shape connecting to the second side of the protuberance;
wherein the length of each individual jutting portion in the axial direction is in a range of from 0.02 mm to 0.18 mm; and
wherein the length in the axial direction of the jutting portion continuously increases from the sliding surface to a position 0.03 mm away from said sliding surface in the radial direction in an amount in the range of 58-67%.

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

3. The multi-piece oil ring according to claim 2 , wherein the oil ring main member has undergone a nitriding treatment.

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

5. The multi-piece oil ring according to claim 4 , wherein the oil ring main member has undergone a nitriding treatment.

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

7. The multi-piece oil ring according to claim 6 , wherein the oil ring main member has undergone a nitriding treatment.

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

9. 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.

10. The multi-piece oil ring according to claim 8 , further comprising a physical vapor deposition (PVD) coating and/or a diamond-like carbon (DLC) coating formed on each of the sliding surfaces.

11. 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.

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

13. 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.

14. The multi-piece oil ring according to claim 1 , wherein the curved surfaces of the jutting portions face away from each other.

15. The multi-piece oil ring according to claim 1 , wherein the curved surfaces of the jutting portions face towards each other.

16. The multi-piece oil ring according to claim 1 , wherein the protuberance tapers in length as it extends from the rail, such that the length of the protuberance in the axial direction decreases from a point where the protuberance extends from the rail to a point where the jutting portion is formed.

Assignees

• Chiba Atsushi
• Fujimura Kazuhiro
• Hiraishi Iwao
• Kajiwara Makoto
• Nippon Piston Ring Co Ltd

Inventors

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

Classifications

• F16J9/206 Primary

  One-piece oil-scraping rings · CPC title

• F16J9/062

  Coiled spring along the entire circumference · CPC title